[Immunobiological blood parameters in rabbits after addition to the diet suspensions of chlorella, sodium sulfate, citrate and chromium chloride].

PubMed

Lesyk, Ia V; Fedoruk, R S; Dolaĭchuk, O P

2013-01-01

We studied the content of glycoproteins and their individual carbohydrate components, the phagocyte activity of neutrophils, phagocyte index, phagocyte number lizotsym and bactericidal activity of the serum concentration of circulating immune complexes and middle mass molecules in the blood of rabbits following administration into the diet chlorella suspension, sodium sulfate, chromium citrate and chromium chloride. The studies were conducted on rabbits weighing 3.7-3.9 kg with altered diet from the first day of life to 118 days old. Rabbits were divided into five groups: the control one and four experimental groups. We found that in the blood of rabbits of experimental groups recieved sodium sulphate, chromium chloride and chromium citrate, the content of glycoprotein's and their carbohydrate components was significantly higher during the 118 days of the study compared with the control group. Feeding rabbits with mineral supplements likely reflected the differences compared with the control parameters of nonspecific resistance in the blood for the study period, which was more pronounced in the first two months of life.

Mononuclear phagocyte subpopulations in the mouse kidney.

PubMed

George, James F; Lever, Jeremie M; Agarwal, Anupam

2017-04-01

Mononuclear phagocytes are the most common cells in the kidney associated with immunity and inflammation. Although the presence of these cells in the kidney has been known for decades, the study of mononuclear phagocytes in the context of kidney function and dysfunction is still at an early stage. The purpose of this review is to summarize the present knowledge regarding classification of these cells in the mouse kidney and to identify relevant questions that would further advance the field and potentially lead to new opportunities for treatment of acute kidney injury and other kidney diseases.

Mononuclear phagocyte subpopulations in the mouse kidney

PubMed Central

George, James F.; Lever, Jeremie M.

2017-01-01

Mononuclear phagocytes are the most common cells in the kidney associated with immunity and inflammation. Although the presence of these cells in the kidney has been known for decades, the study of mononuclear phagocytes in the context of kidney function and dysfunction is still at an early stage. The purpose of this review is to summarize the present knowledge regarding classification of these cells in the mouse kidney and to identify relevant questions that would further advance the field and potentially lead to new opportunities for treatment of acute kidney injury and other kidney diseases. PMID:28100500

Myeloperoxidase-Mediated Iodination by Granulocytes INTRACELLULAR SITE OF OPERATION AND SOME REGULATING FACTORS

PubMed Central

Root, Richard K.; Stossel, Thomas P.

1974-01-01

The intracellular site of operation of the myeloperoxidase-H2O2-halide antibacterial system of granulocytes has been determined by utilizing measurements of the fixation of iodide to trichloracetic acid (TCA) precipitates of subcellular fractions, including intact phagocytic vesicles. Na125I was added to suspensions of guinea pig granulocytes in Krebs-Ringer phosphate buffer, and they were then permitted to phagocytize different particles. Phagocytic vesicles were formed by allowing cells to ingest a paraffin oil emulsion (POE) and collected by flotation on sucrose after homogenization. Measurement of 125I bound to TCA precipitates of the different fractions and the homogenates disclosed that the lysosome-rich fraction obtained by centrifugation from control (nonphagocytizing) cells accounted for a mean 93.1% of the total cellular activity. With phagocytosis of POE, TCA-precipitable iodination increased two- to sevenfold, and the lysosomal contribution fell to a mean 36.9% of the total. The appearance of activity within phagocytic vesicles accounted for almost the entire increase seen with phagocytosis (a mean 75.7%), and iodide was bound within these structures with high specific activity. More iodide was taken up by cells than fixed, regardless of iodide concentration, and was distributed widely throughout the cell rather than selectively trapped within the vesicles. The amount of iodide taken up and fixed varied considerably with the phagocytic particle employed. Yeast particles were found to stimulate iodination to a far greater degree than the ingestion of POE or latex. Such observations are consistent with the concept that the ingested particle is a major recipient of the iodination process. Measurements of metabolic activities related to the formation and utilization of peroxide by cells phagocytizing different particles were made and correlated with iodination. The findings suggest that mechanisms must exist within granulocytes to collect or perhaps even synthesize H2O2 within phagocytic vesicles to serve as substrate for myeloperoxidase. The simultaneous stimulation of other metabolic pathways for peroxide disposal and its release into the medium by phagocytizing cells is consistent with the high diffusability of this important bactericidal substance. PMID:4596505

Evaluation of the efficacy of photodynamic antimicrobial therapy using a phenothiazine compound and LED (red-orange) on the interface: macrophage vs S. aureus

NASA Astrophysics Data System (ADS)

Sampaio, Fernando José P.; de Oliveira, Susana C. P. S.; Monteiro, Juliana S. C.; Pires-Santos, Gustavo M.; Gesteira, Maria F. M.; Pinheiro, Antônio L. B.

2015-03-01

Antimicrobial Photodynamic therapy is a technique in which microorganisms are exposed to a photosensitizing drug and then irradiated with low-intensity visible light of the appropriate wavelength. The resulting photochemical reaction generates cytotoxic reactive oxygen species, such as singlet oxygen and free radicals, which are able to exert bactericidal effect. Much is already known about the photodynamic inactivation of microorganisms: both antibiotic-sensitive and - resistant strains can be successfully photo inactivated, and there is the additional advantage that repeated photosensitization of bacterial cells does not induce a selection of resistant strains. Recently, a series of studies have shown that it is possible to kill bacteria with a light source after the microorganisms have been sensitized with low concentration of dye, such as phenothiazines. The aim of this study was to evaluate the phagocytic function of macrophages J774 against S. aureus in the presence and absence of AmPDT with phenothiazine compound (12.5 μg/mL) and red-orange LED. Experimental groups: Control Group (L-F-), Phenothiazine group (L-F+) LED group (L+F-), Photodynamic therapy group (L+F+). The tests presented in this study were carried out in triplicate. This study demonstrated that AmPDT is able to increase about twice the phagocytic ability of macrophages; however, the bactericidal capacity of these cells did not show a substantial improvement, probably because the oxidative burst was less intense.

The bactericidal effects of anti-MRSA agents with rifampicin and sulfamethoxazole-trimethoprim against intracellular phagocytized MRSA.

PubMed

Yamaoka, Toshimori

2007-06-01

We experienced therapeutic failure with vancomycin in patients with serious methicillin-resistant Staphylococcus aureus (MRSA) infections, in some of whom the bacteria were found to be alive in the leukocytes. We therefore evaluated the antimicrobial activity of several anti-MRSA agents (vancomycin, linezolid, quinupristin/dalfopristin, arbekacin) and co-administered agents (rifampicin, sulfamethoxazole-trimethoprim) against clinically isolated MRSA in phagocytized human polymorphonuclear leukocytes. After allowing the leukocytes to phagocytize the bacteria, the mixture was separated into leukocytes and supernatant, to which MRSA agents were added, and incubated for 24 h. After incubation, the leukocytes were crushed and the intracellular MRSA was cultured quantitatively. Vancomycin resulted in a less than 1% survival ratio of extracellular MRSA, but it was one of the highest ratios of intracellular MRSA with 33.8% compared with other agents. The survival ratios of intracellular MRSA with vancomycin plus rifampicin and with vancomycin plus rifampicin plus sulfamethoxazole-trimethoprim were 0.78% and 1.02%, respectively, which is significantly lower than that of vancomycin. For linezolid, quinupristin/dalfopristin, and arbekacin, there were no significant differences in the survival ratios between monotherapy and combination therapy against either extracellular or intracellular MRSA. The results suggest that the concomitant use of rifampicin or rifampicin plus sulfamethoxazole/trimethoprim with vancomycin is effective for MRSA phagocytized in leukocytes when vancomycin monotherapy is not sufficiently effective. Combination therapy showed no difference in efficacy in the case of linezolid, quinupristin/dalfopristin, and arbekacin.

Impaired clearance of early apoptotic cells mediated by inhibitory IgG antibodies in patients with primary Sjögren's syndrome.

PubMed

Manoussakis, Menelaos N; Fragoulis, George E; Vakrakou, Aigli G; Moutsopoulos, Haralampos M

2014-01-01

Deficient efferocytosis (i.e. phagocytic clearance of apoptotic cells) has been frequently reported in systemic lupus erythematosus (SLE). Todate, patients with primary Sjögren's syndrome (SS) have not been assessed for phagocytosis of apoptotic cells (ApoCell-phagocytosis) and of particulate targets (microbeads, MB-phagocytosis). ApoCell-phagocytosis and MB-phagocytosis were comparatively assessed by flow cytometry in peripheral blood specimens and monocyte-derived macrophage (MDM) preparations from healthy blood donors (HBD) and consecutive SS, SLE and rheumatoid arthritis (RA) patients. Cross-admixture ApoCell-phagocytosis experiments were also performed using phagocytes from HBD or patients, and apoptotic cells pretreated with whole sera or purified serum IgG derived from patients or HBD. Compared to HBD, approximately half of SS and SLE patients studied (but not RA) manifested significantly reduced ApoCell-phagocytosis (p<0.001) and MB-phagocytosis (p<0.003) by blood-borne phagocytes that correlated inversely with disease activity (p≤0.004). In cross-admixture assays, healthy monocytes showed significantly reduced ApoCell-phagocytosis when fed with apoptotic cells that were pretreated with sera or purified serum IgG preparations from SS and SLE patients (p<0.0001, compared to those from HBD or RA). Such aberrant effect of the SS and SLE sera and IgG preparations correlated linearly with their content of IgG antibodies against apoptotic cells (p≤0.0001). Phagocytic dysfunction maybe also present in certain SS and SLE patients, as supported by deficient capacity of MDM for ApoCell-phagocytosis and MB-phagocytosis under patients' serum-free conditions. Similarly to SLE, efferocytosis is frequently impaired in SS and is primarily due to the presence of inhibitory IgG anti-ApoCell antibodies and secondarily to phagocytes' dysfunction.

In vivo activation of equine eosinophils and neutrophils by experimental Strongylus vulgaris infections.

PubMed

Dennis, V A; Klei, T R; Chapman, M R; Jeffers, G W

1988-12-01

Eosinophils and neutrophils from ponies with Strongylus vulgaris-induced eosinophilia (eosinophilic ponies; activated eosinophils and neutrophils) were assayed in vitro for chemotactic and chemokinetic responses to zymosan-activated serum (ZAS) using the filter system in Boyden chambers, for Fc and complement (C) receptors using the EA and EAC-rosette assays, respectively, and for phagocytic and bactericidal activities using opsonized Escherichia coli and the acridine orange method. The responses of activated eosinophils and neutrophils in the above assays were compared with those of eosinophils and neutrophils from S. vulgaris-naive ponies without eosinophilia (noneosinophilic ponies; nonactivated eosinophils and neutrophils). Differences in cell density following centrifugation in a continuous Percoll gradient were used to further characterize the heterogeneity of activated eosinophils and neutrophils. Activated and nonactivated eosinophils demonstrated similar chemotactic responses to ZAS while activated and nonactivated neutrophils demonstrated similar chemokinetic responses to ZAS. A higher percentage of activated eosinophils and neutrophils expressed Fc and C receptors compared with nonactivated cells (P less than 0.05). Generally, higher percentages of eosinophils and neutrophils expressed C than Fc receptors. However, the percentage of neutrophils with both receptors was higher than that of eosinophils. Phagocytosis and killing of E. coli by either type of eosinophil were not consistently observed. Both activated and nonactivated neutrophils phagocytized E. coli and significant differences between the two cell types were not observed. The bacterial activity, however, of activated neutrophils was significantly greater than that obtained using nonactivated neutrophils (P less than 0.05). Activated eosinophils and neutrophils were both separated into two distinct fractions based on differences in cell densities. A higher percentage of band 2 eosinophils (density of 1.106) expressed C receptors than did band 1 eosinophils (density of 1.049) (P less than 0.05). A higher percentage of band 1 neutrophils (density of 1.072) expressed both Fc and C receptors and these neutrophils were more phagocytic and bactericidal than were band 2 neutrophils (density of 1.082) (P less than 0.05). These data suggest that equine eosinophils and neutrophils are activated by chronic S. vulgaris infections.

Evolutionary and Functional Relationships of B Cells from Fish and Mammals: Insights into their Novel Roles in Phagocytosis and Presentation of Particulate Antigen

PubMed Central

Sunyer, J. Oriol

2012-01-01

The evolutionary origins of Ig-producing B cells appear to be linked to the emergence of fish in this planet. There are three major classes of living fish species, which from most primitive to modern they are referred to as agnathan (e.g., lampreys), Chondrichthyes (e.g., sharks), and teleost fish (e.g., rainbow trout). Agnathans do not have immunoglobulin-producing B cells, however these fish contain a subset of lymphocytes-like cells producing type B variable lymphocyte receptors (VLRBs) that appear to act as functional analogs of immunoglobulins. Chondrichthyes fish represent the most primitive living species containing bona-fide immunoglobulin-producing B cells. Their B cells are known to secrete three types of antibodies, IgM, IgW and IgNAR. Teleost fish are also called bony fish since they represent the most ancient living species containing true bones. Teleost B cells produce three different immunoglobulin isotypes, IgM, IgD and the recently described IgT. While teleost IgM is the principal player in systemic immunity, IgT appears to be a teleost immunoglobulin class specialized in mucosal immune responses. Thus far, three major B cell lineages have been described in teleost, those expressing either IgT or IgD, and the most common lineage which co-expresses IgD and IgM. A few years ago, the study of teleost fish B cells revealed for the first time in vertebrates the existence of B cell subsets with phagocytic and intracellular bactericidal capacities. This finding represented a paradigm shift as professional phagocytosis was believed to be exclusively performed by some cells of the myeloid lineage (i.e., macrophages, monocytes, neutrophils). This phagocytic capacity was also found in amphibians and reptiles, suggesting that this innate capacity was evolutionarily conserved in certain B cell subsets of vertebrates. Recently, the existence of subsets of B cells with phagocytic and bactericidal abilities have also been confirmed in mammals. Moreover, it has been shown that phagocytic B-1 B cells have a potent ability to present particulate antigen to CD4+ T cells. Thus, studies carried out originally on fish B cells have lead to the discovery of new innate and adaptive roles of B cells in mammals. This review will concentrate on the evolutionary and functional relationships of fish and mammalian B cells, focusing mainly on the newly discovered roles of these cells in phagocytosis, intracellular killing and presentation of particulate antigen. PMID:22394174

In Vitro and In Vivo studies of monoclonal antibodies with prominent bactericidal activity against Burkholderia pseudomallei and Burkholderia mallei.

PubMed

Zhang, Shimin; Feng, Shaw-Huey; Li, Bingjie; Kim, Hyung-Yong; Rodriguez, Joe; Tsai, Shien; Lo, Shyh-Ching

2011-05-01

Our laboratory has developed more than a hundred mouse monoclonal antibodies (MAbs) against Burkholderia pseudomallei and Burkholderia mallei. These antibodies have been categorized into different groups based on their specificities and the biochemical natures of their target antigens. The current study first examined the bactericidal activities of a number of these MAbs by an in vitro opsonic assay. Then, the in vivo protective efficacy of selected MAbs was evaluated using BALB/c mice challenged intranasally with a lethal dose of the bacteria. The opsonic assay using dimethyl sulfoxide-treated human HL-60 cells as phagocytes revealed that 19 out of 47 tested MAbs (40%) have prominent bactericidal activities against B. pseudomallei and/or B. mallei. Interestingly, all MAbs with strong opsonic activities are those with specificity against either the capsular polysaccharides (PS) or the lipopolysaccharides (LPS) of the bacteria. On the other hand, none of the MAbs reacting to bacterial proteins or glycoproteins showed prominent bactericidal activity. Further study revealed that the antigenic epitopes on either the capsular PS or LPS molecules were readily available for binding in intact bacteria, while the epitopes on proteins/glycoproteins were less accessible to the MAbs. Our in vivo study showed that four MAbs reactive to either the capsular PS or LPS were highly effective in protecting mice against lethal bacterial challenge. The result is compatible with that of our in vitro study. The MAbs with the highest protective efficacy are those reactive to either the capsular PS or LPS of the Burkholderia bacteria.

In Vitro and In Vivo Studies of Monoclonal Antibodies with Prominent Bactericidal Activity against Burkholderia pseudomallei and Burkholderia mallei▿

PubMed Central

Zhang, Shimin; Feng, Shaw-Huey; Li, Bingjie; Kim, Hyung-Yong; Rodriguez, Joe; Tsai, Shien; Lo, Shyh-Ching

2011-01-01

Our laboratory has developed more than a hundred mouse monoclonal antibodies (MAbs) against Burkholderia pseudomallei and Burkholderia mallei. These antibodies have been categorized into different groups based on their specificities and the biochemical natures of their target antigens. The current study first examined the bactericidal activities of a number of these MAbs by an in vitro opsonic assay. Then, the in vivo protective efficacy of selected MAbs was evaluated using BALB/c mice challenged intranasally with a lethal dose of the bacteria. The opsonic assay using dimethyl sulfoxide-treated human HL-60 cells as phagocytes revealed that 19 out of 47 tested MAbs (40%) have prominent bactericidal activities against B. pseudomallei and/or B. mallei. Interestingly, all MAbs with strong opsonic activities are those with specificity against either the capsular polysaccharides (PS) or the lipopolysaccharides (LPS) of the bacteria. On the other hand, none of the MAbs reacting to bacterial proteins or glycoproteins showed prominent bactericidal activity. Further study revealed that the antigenic epitopes on either the capsular PS or LPS molecules were readily available for binding in intact bacteria, while the epitopes on proteins/glycoproteins were less accessible to the MAbs. Our in vivo study showed that four MAbs reactive to either the capsular PS or LPS were highly effective in protecting mice against lethal bacterial challenge. The result is compatible with that of our in vitro study. The MAbs with the highest protective efficacy are those reactive to either the capsular PS or LPS of the Burkholderia bacteria. PMID:21450976

Neutrophil dysfunction in rats with natural gingivitis.

PubMed

Isogai, E; Wakizaka, H; Miura, H; Isogai, H; Hayashi, M

1993-01-01

The functions of polymorphonuclear neutrophils (PMN) from SUS rats with naturally occurring gingivitis were examined by the luminol-dependent chemiluminescence (CL), adherence and bactericidal tests. SUS rats with pre-gingivitis showed lower CL responses of isolated PMNs and whole blood than control rats (RES rats). After plague formation and progression of gingivitis, the CL response gradually increased in SUS rats. RES rats had healthy gingiva and showed no increase in CL responses. Impaired PMN adherence was observed in SUS rats with pre-gingivitis but not in RES rats. PMNs from SUS rats with pre-gingivitis also showed lower bactericidal activity than those from RES rats. Dysfunction of PMNs might induce gingivitis as a result of decreased protection against periodontal pathogens and an elevated level of CL response can be recognized with progression of gingivitis.

Sea urchins in a high-CO2 world: the influence of acclimation on the immune response to ocean warming and acidification

PubMed Central

Harianto, J.; McClintock, J. B.; Byrne, M.

2016-01-01

Climate-induced ocean warming and acidification may render marine organisms more vulnerable to infectious diseases. We investigated the effects of warming and acidification on the immune response of the sea urchin Heliocidaris erythrogramma. Sea urchins were gradually introduced to four combinations of temperature and pHNIST (17°C/pH 8.15, 17°C/pH 7.6, 23°C/pH 8.15 and 23°C/pH 7.6) and then held in temperature–pH treatments for 1, 15 or 30 days to determine if the immune response would adjust to stressors over time. Coelomocyte concentration and type, phagocytic capacity and bactericidal activity were measured on day 1, 15 and 30 with different sea urchins used each time. At each time point, the coelomic fluid of individuals exposed to increased temperature and acidification had the lowest coelomocyte concentrations, exhibited lower phagocytic capacities and was least effective at inhibiting bacterial growth of the pathogen Vibrio anguillarum. Over time, increased temperature alleviated the negative effects of acidification on phagocytic activity. Our results demonstrate the importance of incorporating acclimation time to multiple stressors when assessing potential responses to future ocean conditions and indicate that the immune response of H. erythrogramma may be compromised under near-future ocean warming and acidification. PMID:27559066

Sea urchins in a high-CO2 world: the influence of acclimation on the immune response to ocean warming and acidification.

PubMed

Brothers, C J; Harianto, J; McClintock, J B; Byrne, M

2016-08-31

Climate-induced ocean warming and acidification may render marine organisms more vulnerable to infectious diseases. We investigated the effects of warming and acidification on the immune response of the sea urchin Heliocidaris erythrogramma Sea urchins were gradually introduced to four combinations of temperature and pHNIST (17°C/pH 8.15, 17°C/pH 7.6, 23°C/pH 8.15 and 23°C/pH 7.6) and then held in temperature-pH treatments for 1, 15 or 30 days to determine if the immune response would adjust to stressors over time. Coelomocyte concentration and type, phagocytic capacity and bactericidal activity were measured on day 1, 15 and 30 with different sea urchins used each time. At each time point, the coelomic fluid of individuals exposed to increased temperature and acidification had the lowest coelomocyte concentrations, exhibited lower phagocytic capacities and was least effective at inhibiting bacterial growth of the pathogen Vibrio anguillarum Over time, increased temperature alleviated the negative effects of acidification on phagocytic activity. Our results demonstrate the importance of incorporating acclimation time to multiple stressors when assessing potential responses to future ocean conditions and indicate that the immune response of H. erythrogramma may be compromised under near-future ocean warming and acidification. © 2016 The Author(s).

Streptococcus suis Serotype 2 Biofilms Inhibit the Formation of Neutrophil Extracellular Traps.

PubMed

Ma, Fang; Yi, Li; Yu, Ningwei; Wang, Guangyu; Ma, Zhe; Lin, Huixing; Fan, Hongjie

2017-01-01

Invasive infections caused by Streptococcus suis serotype 2 (SS2) has emerged as a clinical problem in recent years. Neutrophil extracellular traps (NETs) are an important mechanism for the trapping and killing of pathogens that are resistant to phagocytosis. Biofilm formation can protect bacteria from being killed by phagocytes. Until now, there have only been a few studies that focused on the interactions between bacterial biofilms and NETs. SS2 in both a biofilm state and a planktonic cell state were incubated with phagocytes and NETs, and bacterial survival was assessed. DNase I and cytochalasin B were used to degrade NET DNA or suppress phagocytosis, respectively. Extracellular DNA was stained with impermeable fluorescent dye to quantify NET formation. Biofilm formation increased up to 6-fold in the presence of neutrophils, and biofilms were identified in murine tissue. Both planktonic and biofilm cells induced neutrophils chemotaxis to the infection site, with neutrophils increasing by 85.1 and 73.8%, respectively. The bacteria in biofilms were not phagocytized. The bactericidal efficacy of NETs on the biofilms and planktonic cells were equal; however, the biofilm extracellular matrix can inhibit NET release. Although biofilms inhibit NETs release, NETs appear to be an important mechanism to eliminate SS2 biofilms. This knowledge advances the understanding of biofilms and may aid in the development of treatments for persistent infections with a biofilm component.

Interaction between Salmonella typhimurium and phagocytic cells in pigs. Phagocytosis, oxidative burst and killing in polymorphonuclear leukocytes and monocytes.

PubMed

Riber, U; Lind, P

1999-02-22

Interactions between Salmonella typhimurium and peripheral blood leucocytes from healthy, Salmonella-free pigs were investigated in vitro. Both granulocytes and monocytes phagocytized FITC-labelled heat-killed Salmonella bacteria as shown by flow cytometry. Phagocytosis in whole blood and isolated leucocytes was measured as acquired fluorescence in the leukocytes and was both time and dose related. Living, serum-opsonized Salmonella bacteria induced a dose-dependent oxidative burst in PMNs and monocytes as measured by luminol-enhanced chemiluminescence (LC). When opsonized in normal serum the Salmonella bacteria, in the range of 2-5 x 10(7) cfu, induced a LC response in monocytes comparable to the level of responses induced by phorbol myristate acetate (PMA) and opsonized zymosan, and the Salmonella-induced response was only marginally reduced by superoxide dismutase (SOD). Intracellular killing of Salmonella by monocytes was assessed from plate colony counts of lysed monocytes and showed that Salmonella typhimurium was able to survive and proliferate in adherent monocytes in vitro despite a reduction in intracellular cfu during the first hour's incubation in cells from some pigs. Experiments with the exhaustion of oxidative burst in non-adherent monocytes were performed by prestimulation with PMA, heat-killed Salmonella or buffer. Prestimulation with PMA led to a strong reduction in oxidative burst induced by living opsonized Salmonella bacteria, whereas prestimulation with heat-killed bacteria gave rise to an enhanced response. In these experiments intracellular killing of the added living Salmonella gave variable results, in that monocytes from two out of three pigs showed no essential change in intracellular bactericidal activity, but with cells from one pig a less pronounced bactericidal activity was found after prestimulation with PMA.

Phagocytizing activity of PMN from severe trauma patients in different post-traumatic phases during the 10-days post-injury course.

PubMed

Sturm, Ramona; Heftrig, David; Mörs, Katharina; Wagner, Nils; Kontradowitz, Kerstin; Jurida, Katrin; Marzi, Ingo; Relja, Borna

2017-02-01

Phagocytizing leukocytes (granulocytes and monocytes) play a fundamental role in immunological defense against pathogens and clearance of cellular debris after tissue injury due to trauma. According to the "two-hit hypothesis", phagocytes become primed due to/after trauma. Subsequently, a secondary stimulus may lead to their exaggerated response. This immune dysfunction can result in serious infectious complications, also depending on trauma injury pattern. Here, we investigated the phagocytizing capacity of leukocytes, and its correlation to trauma injury pattern. Peripheral whole blood was taken daily from 29 severely injured trauma patients (TP, Injury Severity Score, ISS≥28) for ten days (1-10) following admission to the emergency department (ED). Sixteen healthy volunteers served as controls (HV). Samples were incubated with opsonized Staphylococcus aureus labelled with pHrodo fluorescent reagent and the percentage of phagocytizing activity was assessed by flow cytometry. Abbreviated Injury Scales (AIS)≥3 of head, chest and extremities were used for injury pattern analysis. Overall distribution of active phagocytes (out of 100% phagocytizing leukocytes) in TP included granulocytes with 28.6±1.5% and monocytes with 59.3±1.9% at ED, and was comparable to HV (31.5±1.6% granulocytes and 60.1±1.6% monocytes). The percentage of phagocytizing granulocytes increased significantly after D2 (39.1±1.2%), while the percentage of phagocytizing monocytes (52.0±1.2%, p<0.05) decreased after D2. These changes persisted during the whole time course. Phagocytizing activity of granulocytes (27.9±2.8%) and monocytes (55.2±3.3%) was significantly decreased at ED compared to HV (42.4±4.1% and 78.1±3.1%, respectively). After D2 up to D10, phagocytizing activity was significantly enhanced in granulocytes. Phagocytizing activity of monocytes remained decreased on D1 and has risen continuously during the ten days time course to values comparable to HV. No significant differences in phagocytosis could be associated to certain injury pattern. Our data demonstrate that the increasing percentage of phagocytizing granulocytes may indicate their enhanced mobilization out of bone marrow persisting until post-injury day 10. Furthermore, an initially decreased phagocytizing activity of granulocytes is strongly increased in the 10-days post-injury course. The altered activity of phagocytes due to injury could not be linked to any trauma injury pattern, and emerged rather as a general characteristic of phagocytes after severe trauma. Copyright © 2016. Published by Elsevier GmbH.

Impact of accessory gene regulator (agr) dysfunction on vancomycin pharmacodynamics among Canadian community and health-care associated methicillin-resistant Staphylococcus aureus

PubMed Central

2011-01-01

Background The accessory gene regulator (agr) is a quorum sensing cluster of genes which control colonization and virulence in Staphylococcus aureus. We evaluated agr function in community- (CA) and healthcare-associated (HA) MRSA, to compare the pharmacodynamics and bactericidal activity of vancomycin against agr functional and dysfunctional HA-MRSA and CA-MRSA. Methods 40 clinical isolates of MRSA from the Canadian Nosocomial Infection Surveillance Program were evaluated for delta-haemolysin production, as a surrogate marker of agr function. Time kill experiments were performed for vancomycin at 0 to 64 times the MIC against an initial inoculum of 106 and 108 cfu/ml of agr functional and dysfunctional CA-MRSA and HA-MRSA and these data were fit to a hill-type pharmacodynamic model. Results 15% isolates were agr dysfunctional, which was higher among HA-MRSA (26.3%) versus CA-MRSA (4.76%). Against a low initial inoculum of 106 cfu/ml of CA-MRSA, vancomycin pharmacodynamics were similar among agr functional and dysfunctional strains. However, against a high initial inoculum of 108 cfu/ml, killing activity was notably attenuated against agr dysfunctional CA-MRSA (USA400) and HA-MRSA (USA100). CA-MRSA displayed a 20.0 fold decrease in the maximal reduction in bacterial counts (Emax) which was 3.71 log10 CFU/ml for agr functional vs. 2.41 log10 CFU/ml for agr dysfunctional MRSA (p = 0.0007). Conclusions Dysfunction in agr was less common among CA-MRSA vs. HA-MRSA. agr dysfunction demonstrated an impact on vancomycin bactericidal activity and pharmacodynamics against a high initial inoculum of CA-MRSA and HA-MRSA, which may have implications for optimal antimicrobial therapy against persistent, difficult to treat MRSA infections. PMID:21599878

Impact of accessory gene regulator (agr) dysfunction on vancomycin pharmacodynamics among Canadian community and health-care associated methicillin-resistant Staphylococcus aureus.

PubMed

Tsuji, Brian T; MacLean, Robert D; Dresser, Linda D; McGavin, Martin J; Simor, Andrew E

2011-05-20

The accessory gene regulator (agr) is a quorum sensing cluster of genes which control colonization and virulence in Staphylococcus aureus. We evaluated agr function in community- (CA) and healthcare-associated (HA) MRSA, to compare the pharmacodynamics and bactericidal activity of vancomycin against agr functional and dysfunctional HA-MRSA and CA-MRSA. 40 clinical isolates of MRSA from the Canadian Nosocomial Infection Surveillance Program were evaluated for delta-haemolysin production, as a surrogate marker of agr function. Time kill experiments were performed for vancomycin at 0 to 64 times the MIC against an initial inoculum of 10(6) and 10(8) cfu/ml of agr functional and dysfunctional CA-MRSA and HA-MRSA and these data were fit to a hill-type pharmacodynamic model. 15% isolates were agr dysfunctional, which was higher among HA-MRSA (26.3%) versus CA-MRSA (4.76%). Against a low initial inoculum of 10(6) cfu/ml of CA-MRSA, vancomycin pharmacodynamics were similar among agr functional and dysfunctional strains. However, against a high initial inoculum of 10(8) cfu/ml, killing activity was notably attenuated against agr dysfunctional CA-MRSA (USA400) and HA-MRSA (USA100). CA-MRSA displayed a 20.0 fold decrease in the maximal reduction in bacterial counts (Emax) which was 3.71 log(10) CFU/ml for agr functional vs. 2.41 log(10) CFU/ml for agr dysfunctional MRSA (p = 0.0007). Dysfunction in agr was less common among CA-MRSA vs. HA-MRSA. agr dysfunction demonstrated an impact on vancomycin bactericidal activity and pharmacodynamics against a high initial inoculum of CA-MRSA and HA-MRSA, which may have implications for optimal antimicrobial therapy against persistent, difficult to treat MRSA infections.

Of Men Not Mice: Bactericidal/Permeability-Increasing Protein Expressed in Human Macrophages Acts as a Phagocytic Receptor and Modulates Entry and Replication of Gram-Negative Bacteria

PubMed Central

Balakrishnan, Arjun; Schnare, Markus; Chakravortty, Dipshikha

2016-01-01

Macrophages as immune cells prevent the spreading of pathogens by means of active phagocytosis and killing. We report here the presence of an antimicrobial protein, bactericidal/permeability-increasing protein (BPI) in human macrophages, which actively participates in engulfment and killing of Gram-negative pathogens. Our studies revealed increased expression of BPI in human macrophages during bacterial infection and upon stimulation with various pathogen-associated molecular patterns, viz., LPS and flagellin. Furthermore, during the course of an infection, BPI interacted with Gram-negative bacteria, resulting in enhanced phagocytosis and subsequent control of the bacterial replication. However, it was observed that bacteria which can maintain an active replicating niche (Salmonella Typhimurium) avoid the interaction with BPI during later stages of infection. On the other hand, Salmonella mutants, which cannot maintain a replicating niche, as well as Shigella flexneri, which quit the endosomal vesicle, showed interaction with BPI. These results propose an active role of BPI in Gram-negative bacterial clearance by human macrophages. PMID:27822215

Phagocytic clearance of presynaptic dystrophies by reactive astrocytes in Alzheimer's disease

PubMed Central

Gomez‐Arboledas, Angela; Davila, Jose C.; Sanchez‐Mejias, Elisabeth; Navarro, Victoria; Nuñez‐Diaz, Cristina; Sanchez‐Varo, Raquel; Sanchez‐Mico, Maria Virtudes; Trujillo‐Estrada, Laura; Fernandez‐Valenzuela, Juan Jose; Vizuete, Marisa; Comella, Joan X.; Galea, Elena

2017-01-01

Abstract Reactive astrogliosis, a complex process characterized by cell hypertrophy and upregulation of components of intermediate filaments, is a common feature in brains of Alzheimer's patients. Reactive astrocytes are found in close association with neuritic plaques; however, the precise role of these glial cells in disease pathogenesis is unknown. In this study, using immunohistochemical techniques and light and electron microscopy, we report that plaque‐associated reactive astrocytes enwrap, engulf and may digest presynaptic dystrophies in the hippocampus of amyloid precursor protein/presenilin‐1 (APP/PS1) mice. Microglia, the brain phagocytic population, was apparently not engaged in this clearance. Phagocytic reactive astrocytes were present in 35% and 67% of amyloid plaques at 6 and 12 months of age, respectively. The proportion of engulfed dystrophic neurites was low, around 7% of total dystrophies around plaques at both ages. This fact, along with the accumulation of dystrophic neurites during disease course, suggests that the efficiency of the astrocyte phagocytic process might be limited or impaired. Reactive astrocytes surrounding and engulfing dystrophic neurites were also detected in the hippocampus of Alzheimer's patients by confocal and ultrastructural analysis. We posit that the phagocytic activity of reactive astrocytes might contribute to clear dysfunctional synapses or synaptic debris, thereby restoring impaired neural circuits and reducing the inflammatory impact of damaged neuronal parts and/or limiting the amyloid pathology. Therefore, potentiation of the phagocytic properties of reactive astrocytes may represent a potential therapy in Alzheimer's disease. PMID:29178139

Dynamics of mononuclear phagocyte system Fc receptor function in systemic lupus erythematosus. Relation to disease activity and circulating immune complexes.

PubMed Central

Kimberly, R P; Parris, T M; Inman, R D; McDougal, J S

1983-01-01

Seventeen pairs of longitudinal studies of mononuclear phagocyte system (MPS) Fc receptor function in 15 patients with systemic lupus were performed to explore the dynamic range of Fc receptor dysfunction in lupus and to establish the relationships between MPS function, clinical disease activity and circulating immune complexes (CIC). Fc receptor function was measured by the clearance of IgG sensitized autologous erythrocytes. At the time of first study the degree of MPS dysfunction was correlated with both clinical activity (P less than 0.05) and CIC (P less than 0.05). At follow-up patients with a change in clinical status show significantly larger changes in clearance function compared to clinically stable patients (206 min vs 7 min; P less than 0.001). MPS function changed concordantly with a change in clinical status in all cases (P = 0.002). Longitudinal assessments did not demonstrate concordance of changes in MPS function and CIC, measured by three different assays. The MPS Fc receptor defect in systemic lupus is dynamic and closely associated with disease activity. The lack of concordance of the defect with changes in CIC suggests that either CIC does not adequately reflect receptor site saturation or that other factors may also contribute to the magnitude of MPS dysfunction. PMID:6839542

Erythrocyte and blood antibacterial defense

PubMed Central

2014-01-01

It is an axiom that blood cellular immunity is provided by leukocytes. As to erythrocytes, it is generally accepted that their main function is respiration. Our research provides objective video and photo evidence regarding erythrocyte bactericidal function. Phase-contrast immersion vital microscopy of the blood of patients with bacteremia was performed, and the process of bacteria entrapping and killing by erythrocytes was shot by means of video camera. Video evidence demonstrates that human erythrocytes take active part in blood bactericidal action and can repeatedly engulf and kill bacteria of different species and size. Erythrocytes are extremely important integral part of human blood cellular immunity. Compared with phagocytic leukocytes, the erythrocytes: a) are more numerous; b) are able to entrap and kill microorganisms repeatedly without being injured; c) are more resistant to infection and better withstand the attacks of pathogens; d) have longer life span and are produced faster; e) are inauspicious media for proliferation of microbes and do not support replication of chlamidiae, mycoplasmas, rickettsiae, viruses, etc.; and f) are more effective and uncompromised bacterial killers. Blood cellular immunity theory and traditional view regarding the function of erythrocytes in human blood should be revised. PMID:24883200

In vitro antibody-enzyme conjugates with specific bactericidal activity.

PubMed

Knowles, D M; Sulivan, T J; Parker, C W; Williams, R C

1973-06-01

IgG with antibacterial antibody opsonic activity was isolated from rabbit antisera produced by intravenous hyperimmunization with several test strains of pneumococci, Group A beta-hemolytic streptococci, Staphylococcus aureus, Proteus mirabilis, Pseudomonas aeruginosa, and Escherichia coli. Antibody-enzyme conjugates were prepared, using diethylmalonimidate to couple glucose oxidase to IgG antibacterial antibody preparations. Opsonic human IgG obtained from serum of patients with subacute bacterial endocarditis was also conjugated to glucose oxidase. Antibody-enzyme conjugates retained combining specificity for test bacteria as demonstrated by indirect immunofluorescence. In vitro test for bactericidal activity of antibody-enzyme conjugates utilized potassium iodide, lactoperoxidase, and glucose as cofactors. Under these conditions glucose oxidase conjugated to antibody generates hydrogen peroxide, and lactoperoxidase enzyme catalyzes the reduction of hydrogen peroxide with simultaneous oxidation of I(-) and halogenation and killing of test bacteria. Potent in vitro bactericidal activity of this system was repeatedly demonstrated for antibody-enzyme conjugates against pneumococci, streptococci, S. aureus, P. mirabilis, and E. coli. However, no bactericidal effect was demonstrable with antibody-enzyme conjugates and two test strains of P. aeruginosa. Bactericidal activity of antibody-enzyme conjugates appeared to parallel original opsonic potency of unconjugated IgG preparations. Antibody-enzyme conjugates at concentrations as low as 0.01 mg/ml were capable of intense bactericidal activity producing substantial drops in surviving bacterial counts within 30-60 min after initiation of assay. These in vitro bactericidal systems indicate that the concept of antibacterial antibody-enzyme conjugates may possibly be adaptable as a mechanism for treatment of patients with leukocyte dysfunction or fulminant bacteremia.

Systemic hypoxia enhances exercise-mediated bactericidal and subsequent apoptotic responses in human neutrophils.

PubMed

Wang, Jong-Shyan; Chiu, Ya-Ting

2009-10-01

Phagocytosis and oxidative burst are critical host defense mechanisms in which neutrophils clear invading pathogens. Clearing phagocytic neutrophils by triggering apoptosis is an essential process for controlling inflammation. This study elucidates how various exercise bouts with/without hypoxia affected neutrophil bactericidal activity and subsequent apoptosis in humans. Fifteen sedentary males performed six distinct experimental tests in an air-conditioned normobaric hypoxia chamber: two normoxic exercises [strenuous exercise (SE; up to maximal O2 consumption) and moderate exercise (ME; 50% maximal O2 consumption for 30 min) while exposed to 21% O2], two hypoxic exercises (ME for 30 min while exposed to 12% and 15% O2), and two hypoxic exposures (resting for 30 min while exposed to 12% and 15% O2). The results showed that 1) plasma complement-C3a desArg/C4a desArg/C5a concentrations were increased, 2) expressions of L-selectin/lymphocyte functin-associated antigen-1/Mac-1/C5aR on neutrophils were enhanced, 3) phagocytosis of neutrophils to Esherichia coli and release of neutrophil oxidant products by E. coli were elevated, and 4) E. coli-induced phosphotidylserine exposure or caspase-3 activation of neutrophils were promoted immediately and 2 h after both 12% O2 exposure at rest and with ME as well as normoxic SE. Although neither normoxic ME nor breathing 15% O2 at rest influenced these complement- and neutrophil-related immune responses, ME at both 12% and 15% O2 resulted in enhanced complement activation in the blood, expressions of opsonic/complement receptors on neutrophils, or the bactericidal activity and apoptosis of neutrophils. Moreover, the increased neutrophil oxidant production and apoptosis by normoxic SE and hypoxic ME were ameliorated by treating neutrophils with diphenylene iodonium (a NADPH oxidase inhibitor). Therefore, we conclude that ME at 12-15% O2 enhances bactericidal capacity and facilitates the subsequent apoptosis of neutrophils.

Inactivation of a subpopulation of human neutrophils by exposure to ultrahigh-molecular-weight polyethylene wear debris.

PubMed

Bernard, Louis; Vaudaux, Pierre; Huggler, Elzbieta; Stern, Richard; Fréhel, Claude; Francois, Patrice; Lew, Daniel; Hoffmeyer, Pierre

2007-04-01

Polymorphonuclear neutrophils, a first line of defence against invading microbial pathogens, may be attracted by inflammatory mediators triggered by ultrahigh-molecular-weight polyethylene (UHMWPE) wear particles released from orthopaedic prostheses. Phagocytosis of UHMWPE particles by neutrophils may indirectly compromise their phagocytic-bactericidal mechanisms, thus enhancing host susceptibility to microbial infections. In an in vitro assay, pre-exposure of purified human neutrophils to UHMWPE micrometre- and submicrometre-sized wear particles interfered with subsequent Staphylococcos aureus uptake in a heterogeneous way, as assessed by a dual label fluorescence microscopic assay that discriminated intracellular rhodamine-labelled UHMWPE particles from fluorescein isothiocyanate-labelled S. aureus. Indeed, a higher percentage (44%) of neutrophils having engulfed UHMWPE particles lost the ability to phagocytize S. aureus, compared with UHMWPE-free neutrophils (<3%). Pre-exposure of neutrophils to UHMWPE wear particles did not impair but rather stimulated their oxidative burst response in a chemoluminescence assay. The presence of UHMWPE wear particles did not lead to significant overall consumption of complement-mediated opsonic factors nor decreased surface membrane display of neutrophil complement receptors. In conclusion, engulfment of UHMWPE wear particles led to inactivation of S. aureus uptake in nearly half of the neutrophil population, which may potentially impair host clearance mechanisms against pyogenic infections.

The voltage dependence of NADPH oxidase reveals why phagocytes need proton channels

NASA Astrophysics Data System (ADS)

DeCoursey, Thomas E.; Morgan, Deri; Cherny, Vladimir V.

2003-04-01

The enzyme NADPH oxidase in phagocytes is important in the body's defence against microbes: it produces superoxide anions (O2-, precursors to bactericidal reactive oxygen species). Electrons move from intracellular NADPH, across a chain comprising FAD (flavin adenine dinucleotide) and two haems, to reduce extracellular O2 to O2-. NADPH oxidase is electrogenic, generating electron current (Ie) that is measurable under voltage-clamp conditions. Here we report the complete current-voltage relationship of NADPH oxidase, the first such measurement of a plasma membrane electron transporter. We find that Ie is voltage-independent from -100mV to >0mV, but is steeply inhibited by further depolarization, and is abolished at about +190mV. It was proposed that H+ efflux mediated by voltage-gated proton channels compensates Ie, because Zn2+ and Cd2+ inhibit both H+ currents and O2- production. Here we show that COS-7 cells transfected with four NADPH oxidase components, but lacking H+ channels, produce O2- in the presence of Zn2+ concentrations that inhibit O2- production in neutrophils and eosinophils. Zn2+ does not inhibit NADPH oxidase directly, but through effects on H+ channels. H+ channels optimize NADPH oxidase function by preventing membrane depolarization to inhibitory voltages.

Phagocytosis and Inflammation: Exploring the effects of the components of E-cigarette vapor on macrophages.

PubMed

Ween, Miranda P; Whittall, Jonathan J; Hamon, Rhys; Reynolds, Paul N; Hodge, Sandra J

2017-08-01

E-cigarettes are perceived as harmless; however, evidence of their safety is lacking. New data suggests E-cigarettes discharge a range of compounds capable of physiological damage to users. We previously established that cigarette smoke caused defective alveolar macrophage phagocytosis. The present study compared the effect E-cigarette of components; E-liquid flavors, nicotine, vegetable glycerine, and propylene glycol on phagocytosis, proinflammatory cytokine secretion, and phagocytic recognition molecule expression using differentiated THP-1 macrophages. Similar to CSE, phagocytosis of NTHi bacteria was significantly decreased by E-liquid flavoring (11.65-15.75%) versus control (27.01%). Nicotine also decreased phagocytosis (15.26%). E-liquid, nicotine, and E-liquid+ nicotine reduced phagocytic recognition molecules; SR-A1 and TLR-2. IL-8 secretion increased with flavor and nicotine, while TNF α , IL-1 β , IL-6, MIP-1 α , MIP-1 β , and MCP-1 decreased after exposure to most flavors and nicotine. PG, VG, or PG:VG mix also induced a decrease in MIP-1 α and MIP-1 β We conclude that E-cigarettes can cause macrophage phagocytic dysfunction, expression of phagocytic recognition receptors and cytokine secretion pathways. As such, E-cigarettes should be treated with caution by users, especially those who are nonsmokers. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Mononuclear Phagocytes Are Dispensable for Cardiac Remodeling in Established Pressure-Overload Heart Failure

PubMed Central

Patel, Bindiya; Ismahil, Mohamed Ameen; Hamid, Tariq; Bansal, Shyam S.; Prabhu, Sumanth D.

2017-01-01

Background Although cardiac and splenic mononuclear phagocytes (MPs), i.e., monocytes, macrophages and dendritic cells (DCs), are key contributors to cardiac remodeling after myocardial infarction, their role in pressure-overload remodeling is unclear. We tested the hypothesis that these immune cells are required for the progression of remodeling in pressure-overload heart failure (HF), and that MP depletion would ameliorate remodeling. Methods and Results C57BL/6 mice were subjected to transverse aortic constriction (TAC) or sham operation, and assessed for alterations in MPs. As compared with sham, TAC mice exhibited expansion of circulating LyC6hi monocytes and pro-inflammatory CD206− cardiac macrophages early (1 w) after pressure-overload, prior to significant hypertrophy and systolic dysfunction, with subsequent resolution during chronic HF. In contrast, classical DCs were expanded in the heart in a biphasic manner, with peaks both early, analogous to macrophages, and late (8 w), during established HF. There was no significant expansion of circulating DCs, or Ly6C+ monocytes and DCs in the spleen. Periodic systemic MP depletion from 2 to 16 w after TAC in macrophage Fas-induced apoptosis (MaFIA) transgenic mice did not alter cardiac remodeling progression, nor did splenectomy in mice with established HF after TAC. Lastly, adoptive transfer of splenocytes from TAC HF mice into naïve recipients did not induce immediate or long-term cardiac dysfunction in recipient mice. Conclusions Mononuclear phagocytes populations expand in a phasic manner in the heart during pressure-overload. However, they are dispensable for the progression of remodeling and failure once significant hypertrophy is evident and blood monocytosis has normalized. PMID:28125666

Synergistic effect of a recombinant N-terminal fragment of bactericidal/permeability-increasing protein and cefamandole in treatment of rabbit gram-negative sepsis.

PubMed

Lin, Y; Leach, W J; Ammons, W S

1996-01-01

As a consequence of their bactericidal actions, many antibiotics cause the release of endotoxin, a primary mediator of gram-negative sepsis. Bactericidal/permeability-increasing protein (BPI) has bactericidal activity and neutralizes endotoxin in vitro and in vivo. We sought to examine the effect of a recombinant N-terminal fragment of BPI (rBPI21) in conjunction with cefamandole, a cephalosporin antibiotic, in the treatment of Escherichia coli bacteremia and septic shock in rabbits. Cefamandole (100 mg/kg of body weight) was injected intravenously. This was followed by simultaneous 10-min infusions of E. coli O7:K1 (9 x 10(9) CFU/kg) and rBPI21 (10 mg/kg). rBPI21 was continuously infused for an additional 110 min at 10 mg/kg/h. The administration of rBPI21 in conjunction with the administration of cefamandole prevented the cefamandole-induced increase of free endotoxin in plasma, accelerated bacterial clearance, ameliorated cardiopulmonary dysfunction, and thereby, prevented death, whereas neither agent alone was protective in this animal model. The efficacy of the combined treatment with rBPI21 and cefamandole suggests a synergistic interaction between the two agents. The data indicate that rBPI21 may be useful in conjunction with traditional antibiotic therapy.

Therapeutic potential of carbohydrates as regulators of macrophage activation.

PubMed

Lundahl, Mimmi L E; Scanlan, Eoin M; Lavelle, Ed C

2017-12-15

It is well established for a broad range of disease states, including cancer and Mycobacterium tuberculosis infection, that pathogenesis is bolstered by polarisation of macrophages towards an anti-inflammatory phenotype, known as M2. As these innate immune cells are relatively long-lived, their re-polarisation to pro-inflammatory, phagocytic and bactericidal "classically activated" M1 macrophages is an attractive therapeutic approach. On the other hand, there are scenarios where the resolving inflammation, wound healing and tissue remodelling properties of M2 macrophages are beneficial - for example the successful introduction of biomedical implants. Although there are numerous endogenous and exogenous factors that have an impact on the macrophage polarisation spectrum, this review will focus specifically on prominent macrophage-modulating carbohydrate motifs with a view towards highlighting structure-function relationships and therapeutic potential. Copyright © 2017 Elsevier Inc. All rights reserved.

Pharmacological Targeting of the Host-Pathogen Interaction: Alternatives to Classical Antibiotics to Combat Drug-Resistant Superbugs

PubMed Central

Munguia, Jason; Nizet, Victor

2017-01-01

The rise of multidrug-resistant pathogens and the dearth of new antibiotic development place an existential strain on successful infectious disease therapy. Breakthrough strategies that go beyond classical antibiotic mechanisms are needed to combat this looming public health catastrophe. Reconceptualizing antibiotic therapy in the richer context of the host-pathogen interaction is required for innovative solutions. By defining specific virulence factors, the essence of a pathogen, and pharmacologically neutralizing their activities, one can block disease progression and sensitize microbes to immune clearance. Likewise, host-directed strategies to boost phagocyte bactericidal activity, enhance leukocyte recruitment, or reverse pathogen-induced immunosuppression seek to replicate the success of cancer immunotherapy in the field of infectious diseases. The answer to the threat of multidrug-resistant pathogens lies “outside-the-box” of current antibiotic paradigms. PMID:28283200

IFN-γ protects from apoptotic neutrophil-mediated tissue injury during acute Listeria monocytogenes infection.

PubMed

Wang, Guan; Lin, Ang; Han, Qiuju; Zhao, Huajun; Tian, Zhigang; Zhang, Jian

2018-06-23

Listeria monocytogenes (LM) is a foodborne Gram-positive intracellular pathogen that can cause listeriosis in humans and animals. Although phagocytes are known to be involved in the response to this infection, the role of neutrophils is not entirely clear. Here, we have demonstrated that soon after LM infection, a large number of IFN-γ-producing neutrophils quickly accumulated in the spleen, blood, and peritoneal cavity. Both in vivo and in vitro experiments demonstrated that neutrophils were an important source of IFN-γ. IFN-γ played a critical protective role against acute LM infection, as demonstrated by the poor survival of Ifng -/- mice. Moreover, IFN-γ promoted bacterial clearance by the neutrophils, thereby inhibiting LM-induced neutrophil apoptosis and spleen damage. In addition to this, IFN-γ could effectively drive macrophage-mediated phagocytosis of apoptotic neutrophils, which was accompanied with TGF-β secretion and was involved in protection against tissue injury. Importantly, by phagocytizing apoptotic neutrophils, macrophages obtained myeloperoxidase, an important bactericidal molecule only produced by neutrophils, which further promoted the antibacterial activity of macrophages. These findings demonstrate that neutrophils are an important source of IFN-γ at the early stage of LM infection, which is characterized by both LM elimination and tissue-protective effects. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Alternative activation modifies macrophage resistance to Mycobacterium bovis.

PubMed

Castillo-Velázquez, Uziel; Aranday-Cortés, Elihú; Gutiérrez-Pabello, José A

2011-07-05

The aim of this study was to evaluate the influence of macrophage alternative activation in the intracellular pathogen natural disease resistance phenotype of the host. Macrophage monolayers from resistant (R) (3) or susceptible (S) (3) cattle donors were treated with 10 ng/ml of bovine recombinant IL-4 (rbIL-4), and infected with virulent and avirulent Mycobacterium bovis (MOI 10:1). Bactericidal assays were performed to assess the bacterial phagocytic index and intracellular survival. Total RNA was reverse transcribed and used to analyze the relative changes in gene expression of IL-10, IL-12, IL-18 IL-1β, TNF-α, MCP-1, MCP-2, IL-6, MIP-1, MIP-3, iNOS, ARGII and SLAM by real time PCR. Cell supernatants were collected and nitric oxide and arginase production was assessed. Apoptosis induction was measured by TUNEL. IL-4 treatment increased the phagocytic index in both R and S macrophages; however intracellular survival was augmented mainly in S macrophages. Alternative activation decreased gene expression of pro-inflammatory cytokines, nitric oxide production and DNA fragmentation mainly in R macrophages. On the other hand, arginase production was not different between R and S macrophages. Alternative activation modifies the macrophage response against M. bovis. IL-4 treatment minimized the functional differences that exist between R and S macrophages. Copyright © 2011. Published by Elsevier B.V.

InhA1-Mediated Cleavage of the Metalloprotease NprA Allows Bacillus cereus to Escape From Macrophages.

PubMed

Haydar, Abbass; Tran, Seav-Ly; Guillemet, Elisabeth; Darrigo, Claire; Perchat, Stéphane; Lereclus, Didier; Coquet, Laurent; Jouenne, Thierry; Ramarao, Nalini

2018-01-01

Bacillus cereus is a Gram-positive spore-forming bacterium causing food poisoning and serious opportunistic infections. These infections are characterized by bacterial accumulation in the host despite the induction of inflammation. To circumvent inflammation, bacteria must resist the bactericidal activity of professional phagocytes, which constitute a first line of host defense against pathogens. Interactions between phagocytic cells and B. cereus are still poorly characterized and the mechanism of resistance to the host immune system is not known yet. We have previously shown that the spores are phagocytosed by macrophages but survive and escape from these cells. The metalloprotease InhA1 is a key effector involved in these processes. inhA1 -deficient spores are retained intracellularly, in contrast to the wild type strain spores. NprA is also a B. cereus metalloprotease able to cleave tissue components such as fibronectin, laminin, and collagen. Here, we show that NprA, concomitantly secreted with InhA1 in the B. cereus secretome, is essential to promote bacterial escape from macrophages. We show that InhA1 cleaves NprA at specific sites. This cleavage allows liberation of the mature form of the NprA protein in the supernatant of the wild type strain. This mature form of NprA is actually the principal effector allowing bacterial escape from host macrophages.

Cyclic AMP-Elevating Capacity of Adenylate Cyclase Toxin-Hemolysin Is Sufficient for Lung Infection but Not for Full Virulence of Bordetella pertussis

PubMed Central

Skopova, Karolina; Tomalova, Barbora; Kanchev, Ivan; Rossmann, Pavel; Svedova, Martina; Adkins, Irena; Bibova, Ilona; Tomala, Jakub; Masin, Jiri; Guiso, Nicole; Osicka, Radim; Sedlacek, Radislav; Kovar, Marek

2017-01-01

ABSTRACT The adenylate cyclase toxin-hemolysin (CyaA, ACT, or AC-Hly) of Bordetella pertussis targets phagocytic cells expressing the complement receptor 3 (CR3, Mac-1, αMβ2 integrin, or CD11b/CD18). CyaA delivers into cells an N-terminal adenylyl cyclase (AC) enzyme domain that is activated by cytosolic calmodulin and catalyzes unregulated conversion of cellular ATP into cyclic AMP (cAMP), a key second messenger subverting bactericidal activities of phagocytes. In parallel, the hemolysin (Hly) moiety of CyaA forms cation-selective hemolytic pores that permeabilize target cell membranes. We constructed the first B. pertussis mutant secreting a CyaA toxin having an intact capacity to deliver the AC enzyme into CD11b-expressing (CD11b+) host phagocytes but impaired in formation of cell-permeabilizing pores and defective in cAMP elevation in CD11b− cells. The nonhemolytic AC+ Hly− bacteria inhibited the antigen-presenting capacities of coincubated mouse dendritic cells in vitro and skewed their Toll-like receptor (TLR)-triggered maturation toward a tolerogenic phenotype. The AC+ Hly− mutant also infected mouse lungs as efficiently as the parental AC+ Hly+ strain. Hence, elevation of cAMP in CD11b− cells and/or the pore-forming capacity of CyaA were not required for infection of mouse airways. The latter activities were, however, involved in bacterial penetration across the epithelial layer, enhanced neutrophil influx into lung parenchyma during sublethal infections, and the exacerbated lung pathology and lethality of B. pertussis infections at higher inoculation doses (>107 CFU/mouse). The pore-forming activity of CyaA further synergized with the cAMP-elevating activity in downregulation of major histocompatibility complex class II (MHC-II) molecules on infiltrating myeloid cells, likely contributing to immune subversion of host defenses by the whooping cough agent. PMID:28396322

Immunomodulative properties of humic peat preparations

NASA Astrophysics Data System (ADS)

Stepchenko, L. M.; Syedykh, N. J.

2010-05-01

It is proved, that the humic peat preparations promote the resistance of plants, animals and poultry to the influence of both abyotyc and byotyc extreme factors of external environment, to action. It was shown by us before, that biologically active compounds from peat promote stability against different diseases of agricultural animals and poultry. We conducted researches of humic preparations influence (hydrohumate and oxyhumate) on several indexes of immunoreactivity of the organisms of chickens broilers, ostriches, cows and laboratory rats. It is found out, that adding of humic preparations to forage or drinking water results in the normalization of immunity indexes; in particular, leucocytes level, in the increase of the level of some classes of immunoglobuline in blood, of haemoglobin level, T- and B-lymphocytes level, as well as common unspecific resistance - lyzocymic, phagocytic and bactericidic activity. These results allow to suggest that the peat humic preparations show immunomodulative activity, influencing both on humoral and cel immunity links.

Pharmacological Targeting of the Host-Pathogen Interaction: Alternatives to Classical Antibiotics to Combat Drug-Resistant Superbugs.

PubMed

Munguia, Jason; Nizet, Victor

2017-05-01

The rise of multidrug-resistant pathogens and the dearth of new antibiotic development place an existential strain on successful infectious disease therapy. Breakthrough strategies that go beyond classical antibiotic mechanisms are needed to combat this looming public health catastrophe. Reconceptualizing antibiotic therapy in the richer context of the host-pathogen interaction is required for innovative solutions. By defining specific virulence factors, the essence of a pathogen, and pharmacologically neutralizing their activities, one can block disease progression and sensitize microbes to immune clearance. Likewise, host-directed strategies to boost phagocyte bactericidal activity, enhance leukocyte recruitment, or reverse pathogen-induced immunosuppression seek to replicate the success of cancer immunotherapy in the field of infectious diseases. The answer to the threat of multidrug-resistant pathogens lies 'outside the box' of current antibiotic paradigms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Efferocytosis is an innate antibacterial mechanism

PubMed Central

Martin, Constance J.; Booty, Matthew G.; Rosebrock, Tracy R.; Nunes-Alves, Cláudio; Desjardins, Danielle M.; Keren, Iris; Fortune, Sarah M.; Remold, Heinz G.; Behar, Samuel M.

2012-01-01

Summary Mycobacterium tuberculosis persists within macrophages in an arrested phagosome and depends upon necrosis to elude immunity and disseminate. Although apoptosis of M. tuberculosis-infected macrophages is associated with reduced bacterial growth, the bacteria are relatively resistant to death mechanisms, leaving the mechanisms underlying this observation unresolved. We find that following apoptosis, M. tuberculosis-infected macrophages are rapidly taken up by uninfected macrophages through efferocytosis, a dedicated apoptotic cell engulfment process. Efferocytosis of M. tuberculosis sequestered within an apoptotic macrophage further compartmentalizes the bacterium and delivers it along with the apoptotic cell debris to the lysosomal compartment. M. tuberculosis is killed only after efferocytosis, indicating that apoptosis itself is not intrinsically bactericidal but requires subsequent phagocytic uptake and lysosomal fusion of the apoptotic body harboring the bacterium. While efferocytosis is recognized as a constitutive housekeeping function of macrophages, these data indicate that it can also function as an antimicrobial effector mechanism. PMID:22980326

Bactericidal impact of Ag, ZnO and mixed AgZnO colloidal nanoparticles on H37Rv Mycobacterium tuberculosis phagocytized by THP-1 cell lines.

PubMed

Jafari, Alireza; Mosavari, Nader; Movahedzadeh, Farahnaz; Nodooshan, Saeedeh Jafari; Safarkar, Roya; Moro, Rossella; Kamalzadeh, Morteza; Majidpour, Ali; Boustanshenas, Mina; Mosavi, Tahereh

2017-09-01

The purpose of this research project was to infection of human macrophages (THP-1) cell lines by H 37 Rv strain of Mycobacterium tuberculosis (H 37 RvMTB) and find out the ratio/dilution of mixture silver (Ag NPs) and zinc oxide nanoparticles (ZnO NPs) whose ability to eliminate phagocytized bacteria compared to rifampicin. The colloidal Ag NPs and ZnO NPs were synthesized and their characteristics were evaluated. The THP-1 cell lines were infected with different concentration of H 37 RvMTB. Next, the infected cells were treated with different ratios/dilutions of Ag NPs, ZnO NPs and rifampicin. The THP-1 were lysed and were cultured in Lowenstein-Jensen agar medium, for eight weeks. The TEM and AFM images of NPs and H 37 RvMTB were supplied. It is observed that Ag NPs, 2 Ag :8 ZnO and 8 Ag :2 ZnO did not have any anti-tubercular effects on phagocytized H 37 RvMTB. Conversely, ZnO NPs somehow eliminated 18.7 × 10 4  CFU ml -1 of H 37 RvMTB in concentration of ∼ 0.468 ppm. To compare with 40 ppm of rifampicin, ∼ 0.663 ppm of 5 Ag :5 ZnO had the ability to kill of H 37 RvMTB, too. Based on previous research, ZnO NPs had strong anti-tubercular impact against H 37 RvMTB to in-vitro condition, but it was toxic in concentration of ∼ 0.468 ppm to both of THP-1 and normal lung (MRC-5) cell lines. It also seems that 5 Ag :5 ZnO is justified because in concentration of ∼ 0.663 ppm of 5 Ag :5 ZnO , phagocytized H 37 RvMTB into the THP-1 had died without any toxicity effects against THP-1 and also MRC-5 cell lines. It is obvious that the mixture of colloidal silver and zinc oxide NPs with ratio of 5 Ag :5 ZnO would be trustworthy options as anti-tubercular nano-drugs in future researches. Copyright © 2017. Published by Elsevier Ltd.

Enhanced bactericidal activity against Escherichia coli in calves fed Morinda citrifolia (Noni) puree.

PubMed

Schäfer, M; Sharp, P; Brooks, V J; Xu, J; Cai, J; Keuler, N S; Peek, S F; Godbee, R G; Schultz, R D; Darien, B J

2008-01-01

Although adequate colostrum intake and properly used antibiotics can provide much protection for the bovine neonate, increased antibiotic scrutiny and consumer demand for organic products have prompted investigations of natural immunomodulators for enhancing calf health. One plant-based immunomodulator, Morinda citrifolia (noni) fruit, is a well-recognized natural product that has a broad range of immunomodulatory effects. Neonatal calves fed noni puree would demonstrate whole blood phagocytic capacity in Gram-negative and Gram-positive in vitro assays. Blood samples from 18 neonatal Holstein bull calves. Calves were divided into 2 groups: Group 1 comprised control calves, whereas Group 2 received 30 mL of noni puree twice a day in milk replacer. Day 0 blood samples were obtained between 36 and 48 hours of age before the first feeding of puree. Ethylenediaminetetraacetic acid anticoagulated blood was collected from each calf on days 0, 3, 7, and 14. Bactericidal assays were performed to estimate the percentage killing of Escherichia coli and Staphylococcus epidermidis. Blood samples from noni puree-fed calves displayed significantly more E. coli bacterial killing than did controls on day 14, and although differences were not significant on days 0, 3, and 7, bacterial killing progressively increased over time. There was no significant difference between the groups for S. epidermidis killing. The immunomodulatory effect of noni puree may prove valuable in the future as production animal antibiotic use becomes more restricted. Additional clinical trials are warranted to investigate the clinical application of noni puree in promoting calf health.

Lysosomal Degradation Is Required for Sustained Phagocytosis of Bacteria by Macrophages.

PubMed

Wong, Ching-On; Gregory, Steven; Hu, Hongxiang; Chao, Yufang; Sepúlveda, Victoria E; He, Yuchun; Li-Kroeger, David; Goldman, William E; Bellen, Hugo J; Venkatachalam, Kartik

2017-06-14

Clearance of bacteria by macrophages involves internalization of the microorganisms into phagosomes, which are then delivered to endolysosomes for enzymatic degradation. These spatiotemporally segregated processes are not known to be functionally coupled. Here, we show that lysosomal degradation of bacteria sustains phagocytic uptake. In Drosophila and mammalian macrophages, lysosomal dysfunction due to loss of the endolysosomal Cl - transporter ClC-b/CLCN7 delayed degradation of internalized bacteria. Unexpectedly, defective lysosomal degradation of bacteria also attenuated further phagocytosis, resulting in elevated bacterial load. Exogenous application of bacterial peptidoglycans restored phagocytic uptake in the lysosomal degradation-defective mutants via a pathway requiring cytosolic pattern recognition receptors and NF-κB. Mammalian macrophages that are unable to degrade internalized bacteria also exhibit compromised NF-κB activation. Our findings reveal a role for phagolysosomal degradation in activating an evolutionarily conserved signaling cascade, which ensures that continuous uptake of bacteria is preceded by lysosomal degradation of microbes. Copyright © 2017 Elsevier Inc. All rights reserved.

2A4 binds soluble and insoluble light chain aggregates from AL amyloidosis patients and promotes clearance of amyloid deposits by phagocytosis †.

PubMed

Renz, Mark; Torres, Ronald; Dolan, Philip J; Tam, Stephen J; Tapia, Jose R; Li, Lauri; Salmans, Joshua R; Barbour, Robin M; Shughrue, Paul J; Nijjar, Tarlochan; Schenk, Dale; Kinney, Gene G; Zago, Wagner

2016-09-01

Amyloid light chain (AL) amyloidosis is characterized by misfolded light chain (LC) (amyloid) deposition in various peripheral organs, leading to progressive dysfunction and death. There are no regulatory agency-approved treatments for AL amyloidosis, and none of the available standard of care approaches directly targets the LC protein that constitutes the amyloid. NEOD001, currently in late-stage clinical trials, is a conformation-specific, anti-LC antibody designed to specifically target misfolded LC aggregates and promote phagocytic clearance of AL amyloid deposits. The present study demonstrated that the monoclonal antibody 2A4, the murine form of NEOD001, binds to patient-derived soluble and insoluble LC aggregates and induces phagocytic clearance of AL amyloid in vitro. 2A4 specifically labeled all 21 fresh-frozen organ samples studied, which were derived from 10 patients representing both κ and λ LC amyloidosis subtypes. 2A4 immunoreactivity largely overlapped with thioflavin T-positive labeling, and 2A4 bound both soluble and insoluble LC aggregates extracted from patient tissue. Finally, 2A4 induced macrophage engagement and phagocytic clearance of AL amyloid deposits in vitro. These findings provide further evidence that 2A4/NEOD001 can effectively clear and remove human AL-amyloid from tissue and further support the rationale for the evaluation of NEOD001 in patients with AL amyloidosis.

β-1,3 glucan derived from Euglena gracilis and Algamune™ enhances innate immune responses of red drum (Sciaenops ocellatus L.).

PubMed

Yamamoto, Fernando Y; Yin, Fei; Rossi, Waldemar; Hume, Michael; Gatlin, Delbert M

2018-06-01

To reduce susceptibility to stressors and diseases, immune-modulators such as β-glucans have been proven effective tools to enhance the innate immune responses of fish. Consequently, commercial sources of this polysaccharide are becoming increasingly more available. Algamune™ is a commercial additive produced from Euglena gracilis, as a source of linear β-1,3-glucan. In order to evaluate the immunomodulatory effects of this β-glucan product, the present study assessed the innate immune parameters of red drum (Sciaenops ocellatus) exposed to Algamune™ ex vivo and in vivo. Isolated kidney phagocytes were incubated with graded concentrations (0, 0.2, 0.4, 0.8, 1.6 and 3.2 mg L -1 ) of dried Euglena gracilis (Algamune™) as well as purified Paramylon (linear β-1,3 glucan). Increased bactericidal activity against Streptococcus iniae, and production of intracellular O 2 - anion superoxide were stimulated by both β-glucan sources. A reduced activity of extracellular anion superoxide was observed by the phagocytes incubated with Algamune ™. After corroborating the effectiveness of the glucan source ex vivo, a feeding trial was conducted using red drum juveniles (∼26.6 g initial weight). Fish were fed diets with graded levels of Algamune™ (0, 100, 200, 400 and 800 mg kg -1 ) twice daily for 21 days. No significant differences were detected regarding production performance parameters. At the end of the feeding trial, blood, intestinal content, and kidney were sampled. Intestinal microbiota from fecal material was analyzed through denaturing gradient gel electrophoresis (DGGE) and found to be similar among all treatments. No significant differences were detected for oxidative radical production from whole blood, and isolated phagocytes, and plasma lysozyme activity. However, the total hemolytic activity of red drum plasma was increased in fish fed 100 and 200 mg kg -1 of dietary Algamune™ when compared to fish fed the basal diet. Based on results from both ex vivo and in vivo trials, β-glucan from Algamune™ was demonstrated to have a moderate immunostimulatory effects on red drum. Copyright © 2018 Elsevier Ltd. All rights reserved.

Efferocytosis is an innate antibacterial mechanism.

PubMed

Martin, Constance J; Booty, Matthew G; Rosebrock, Tracy R; Nunes-Alves, Cláudio; Desjardins, Danielle M; Keren, Iris; Fortune, Sarah M; Remold, Heinz G; Behar, Samuel M

2012-09-13

Mycobacterium tuberculosis persists within macrophages in an arrested phagosome and depends upon necrosis to elude immunity and disseminate. Although apoptosis of M. tuberculosis-infected macrophages is associated with reduced bacterial growth, the bacteria are relatively resistant to other forms of death, leaving the mechanism underlying this observation unresolved. We find that after apoptosis, M. tuberculosis-infected macrophages are rapidly taken up by uninfected macrophages through efferocytosis, a dedicated apoptotic cell engulfment process. Efferocytosis of M. tuberculosis sequestered within an apoptotic macrophage further compartmentalizes the bacterium and delivers it along with the apoptotic cell debris to the lysosomal compartment. M. tuberculosis is killed only after efferocytosis, indicating that apoptosis itself is not intrinsically bactericidal but requires subsequent phagocytic uptake and lysosomal fusion of the apoptotic body harboring the bacterium. While efferocytosis is recognized as a constitutive housekeeping function of macrophages, these data indicate that it can also function as an antimicrobial effector mechanism. Copyright © 2012 Elsevier Inc. All rights reserved.

2A4 binds soluble and insoluble light chain aggregates from AL amyloidosis patients and promotes clearance of amyloid deposits by phagocytosis †

PubMed Central

Renz, Mark; Torres, Ronald; Dolan, Philip J.; Tam, Stephen J.; Tapia, Jose R.; Li, Lauri; Salmans, Joshua R.; Barbour, Robin M.; Shughrue, Paul J.; Nijjar, Tarlochan; Schenk, Dale; Kinney, Gene G.; Zago, Wagner

2016-01-01

Abstract Amyloid light chain (AL) amyloidosis is characterized by misfolded light chain (LC) (amyloid) deposition in various peripheral organs, leading to progressive dysfunction and death. There are no regulatory agency–approved treatments for AL amyloidosis, and none of the available standard of care approaches directly targets the LC protein that constitutes the amyloid. NEOD001, currently in late-stage clinical trials, is a conformation-specific, anti-LC antibody designed to specifically target misfolded LC aggregates and promote phagocytic clearance of AL amyloid deposits. The present study demonstrated that the monoclonal antibody 2A4, the murine form of NEOD001, binds to patient-derived soluble and insoluble LC aggregates and induces phagocytic clearance of AL amyloid in vitro. 2A4 specifically labeled all 21 fresh-frozen organ samples studied, which were derived from 10 patients representing both κ and λ LC amyloidosis subtypes. 2A4 immunoreactivity largely overlapped with thioflavin T–positive labeling, and 2A4 bound both soluble and insoluble LC aggregates extracted from patient tissue. Finally, 2A4 induced macrophage engagement and phagocytic clearance of AL amyloid deposits in vitro. These findings provide further evidence that 2A4/NEOD001 can effectively clear and remove human AL-amyloid from tissue and further support the rationale for the evaluation of NEOD001 in patients with AL amyloidosis. PMID:27494229

Our Immune System

MedlinePlus

... can stop now! 9 Another protector is the Phagocyte (Phag-o-cyte). Phagocytes kill germs by eating them! They also send signals to other Phagocytes Calling all Phagocytes! Calling all Phagocytes! Help! Help! ...

Effect of Excoecaria agallocha on non-specific immune responses and disease resistance of Oreochromis niloticus against Streptococcus agalactiae.

PubMed

Laith, A A; Mazlan, A G; Effendy, A W; Ambak, M A; Nurhafizah, W W I; Alia, A S; Jabar, A; Najiah, M

2017-06-01

The current study was designed to evaluate the effects of Excoecaria agallocha leaf extracts on immune mechanisms and resistance of tilapia, Oreochromis niloticus, after challenge with Streptococcus agalactiae. Fish were divided into 6 groups; groups 1-5 fed with E. agallocha leaf extracts at 10, 20, 30, 40 and 50mgkg -1 level, respectively. Group 6 were fed without extract addition and acted as control. E. agallocha extracts were administered as feed supplement in fish diet for 28days and the hematological, immunological, and growth performance studies were conducted. Fish were infected with S. agalactiae at a dose of 15×105CFUmL -1 and the total white blood cell (WBC), phagocytosis and respiratory burst activities of leukocytes, serum bactericidal activity, lysozyme, total protein, albumin, and globulin levels were monitored and mortalities recorded for 15days post infection. Results revealed that feeding O. niloticus with 50mgkg -1 of E. agallocha enhanced WBC, phagocytic, respiratory burst, serum bactericidal and lysozyme activities on day 28 pre-challenge and on 3rd, 6th, 9th, 12th and 15th day post-challenge as compared to control. Total protein and albumin were not enhanced by E. agallocha diet. E. agallocha increased the survival of fish after challenge with S. agalactiae. The highest mortality rate (97%) was observed in control fish and the lowest mortality (27%) was observed with group fed with 50mgkg -1 extract. The results indicate that dietary intake of E. agallocha methanolic leaf extract in O. niloticus enhances the non-specific immunity and disease resistance against S. agalactiae pathogen. Copyright © 2017. Published by Elsevier Ltd.

Functional Activity of Antibodies Directed towards Flagellin Proteins of Non-Typhoidal Salmonella

PubMed Central

Boyd, Mary A.; Wang, Jin Y.; Tulapurkar, Mohan E.; Pasetti, Marcela F.; Levine, Myron M.; Simon, Raphael

2016-01-01

Non-typhoidal Salmonella (NTS) serovars Typhimurium and Enteritidis are major causes of invasive bacterial infections in children under 5 years old in sub-Saharan Africa, with case fatality rates of ~20%. There are no licensed NTS vaccines for humans. Vaccines that induce antibodies against a Salmonella Typhi surface antigen, Vi polysaccharide, significantly protect humans against typhoid fever, establishing that immune responses to Salmonella surface antigens can be protective. Flagella proteins, abundant surface antigens in Salmonella serovars that cause human disease, are also powerful immunogens, but the functional capacity of elicited anti-flagellar antibodies and their role in facilitating bacterial clearance has been unclear. We examined the ability of anti-flagellar antibodies to mediate microbial killing by immune system components in-vitro and assessed their role in protecting mice against invasive Salmonella infection. Polyclonal (hyperimmune sera) and monoclonal antibodies raised against phase 1 flagellin proteins of S. Enteritidis and S. Typhimurium facilitated bacterial uptake and killing of the homologous serovar pathogen by phagocytes. Polyclonal anti-flagellar antibodies accompanied by complement also achieved direct bacterial killing. Serum bactericidal activity was restricted to Salmonella serovars expressing the same flagellin used as immunogen. Notably, individual anti-flagellin monoclonal antibodies with complement were not bactericidal, but this biological activity was restored when different monoclonal anti-flagellin antibodies were combined. Passive transfer immunization with a monoclonal IgG antibody specific for phase 1 flagellin from S. Typhimurium protected mice against lethal challenge with a representative African invasive S. Typhimurium strain. These findings have relevance for the use of flagellin proteins in NTS vaccines, and confirm the role of anti-flagellin antibodies as mediators of protective immunity. PMID:26998925

Microautophagy in nutritive phagocytes of sea urchins.

PubMed

Kalachev, Alexander V; Yurchenko, Olga V

2017-01-01

Two types of cells were observed in germinative epithelium of male and female sea urchins: germ cells and somatic accessory cells; the latter referred to as nutritive phagocytes. At the onset of gametogenesis, nutritive phagocytes accumulate nutrients and greatly increase in their size. As gametogenesis progresses, the accumulated nutrients are transferred from nutritive phagocytes into developing gametes, and size of the nutritive phagocytes decreases. An electron microscopic study of nutritive phagocytes in sea urchins, Strongylocentrotus intermedius, at different stages of annual reproductive cycle showed for the first time that both macro- and microautophagy take place in nutritive phagocytes. Both processes occur simultaneously and regulate size and composition of nutritive phagocytes in male and female sea urchins. Nutritive phagocytes consume redundant cytoplasm via macroautophagy. Microautophagy is probably involved in consumption of redundant membranes that appear within nutritive phagocytes due to destruction of nutrient-storing globules, macroautophagy, and phagocytosis of germ cells or their remnants.

Immunological characterization of pulmonary intravascular macrophages

NASA Technical Reports Server (NTRS)

Chitko-McKown, C. G.; Reddy, D. N.; Chapes, S. K.; McKown, R. D.; Blecha, F.; Spooner, B. S. (Principal Investigator)

1992-01-01

Pulmonary intravascular macrophages (PIMs) are lung macrophages found apposed to the endothelium of pulmonary capillaries. In many species, they are responsible for the clearance of blood-borne particulates and pathogens; however, little else is known about their roles as immunologic effector cells. We compared PIMs with pulmonary alveolar macrophages (PAMs) to determine the relative immunological activities of these two cell populations. Our results suggested that both populations possess similar phagocytic and bactericidal activities. In assays measuring cytotoxicity, PIMs were more cytotoxic than PAMs against virally infected target cells; however, differences between these macrophage populations were not as marked when noninfected targets were used. LPS-stimulated PIMs produced more T-cell proliferative cytokines than PAMs, and both populations of nonstimulated macrophages produced similar amounts of the cytokines. In contrast, PAMs produced more TNF alpha and NO2- than PIMs when both populations were stimulated with LPS; however, nonstimulated PAMs and PIMs produced similar amounts of TNF alpha and NO2. These data suggest that bovine PIMs are immunologically active. Differences between the degrees of activity of PIMs and PAMs indicate that these macrophage populations may have different roles in lung surveillance.

Understanding the Mechanism of Translocation of Adenylate Cyclase Toxin across Biological Membranes

PubMed Central

Ostolaza, Helena; Martín, César; González-Bullón, David; Uribe, Kepa B.; Etxaniz, Asier

2017-01-01

Adenylate cyclase toxin (ACT) is one of the principal virulence factors secreted by the whooping cough causative bacterium Bordetella pertussis, and it has a critical role in colonization of the respiratory tract and establishment of the disease. ACT targets phagocytes via binding to the CD11b/CD18 integrin and delivers its N-terminal adenylate cyclase (AC) domain directly to the cell cytosol, where it catalyzes unregulated conversion of cytosolic ATP into cAMP upon activation by binding to cellular calmodulin. High cAMP levels disrupt bactericidal functions of the immune cells, ultimately leading to cell death. In spite of its relevance in the ACT biology, the mechanism by which its ≈400 amino acid-long AC domain is transported through the target plasma membrane, and is released into the target cytosol, remains enigmatic. This article is devoted to refresh our knowledge on the mechanism of AC translocation across biological membranes. Two models, the so-called “two-step model” and the recently-proposed “toroidal pore model”, will be considered. PMID:28934133

The cytochemical and ultrastructural characteristics of phagocytes in the Pacific oyster Crassostrea gigas.

PubMed

Jiang, Shuai; Jia, Zhihao; Xin, Lusheng; Sun, Ying; Zhang, Ran; Wang, Weilin; Wang, Lingling; Song, Linsheng

2016-08-01

Phagocytes have been proved to play vital roles in the innate immune response. However, the cellular characteristics of phagocytes in invertebrates, especially in molluscs, remain largely unknown. In the present study, fluorescence activated cell sorting (FACS) was employed to sort the phagocytes from the non-phagocytic haemocytes of the Pacific oyster Crassostrea gigas. The cytochemical staining analysis revealed that phagocytes were positive staining for α-naphthyl acetate esterase and myeloperoxidase, while negative staining for toluidine blue and periodic acid-Schiff. The non-phagocytic haemocytes exhibited positive staining for periodic acid-Schiff, weak positive staining for toluidine blue, but negative staining for α-naphthyl acetate esterase and myeloperoxidase. In addition, phagocytes exhibited ultrastructural cellular features similar to those of macrophages, with large cell diameter, rough cell membrane and extended pseudopodia revealed by the scanning electron microscopy, while the non-phagocytic haemocytes exhibited small cell diameter, smooth cell surface and round spherical shape. Transmission electron microscopy further demonstrated that phagocytes were abundant of cytoplasmic bodies and mitochondria, while non-phagocytic haemocytes were characterized as the comparatively large cell nucleus with contorted and condensed heterochromatin adherent to the nuclear envelope. Moreover, compared with non-phagocytic haemocytes, phagocytes exhibited significantly higher levels of intracellular cytokines, including tumor necrosis factor, interferon-like protein and interleukin-17, and significantly higher abundance of lysosome and reactive oxygen species, which were of great importance to the activation of immune response and pathogen clearance. Taken together, these findings revealed the different cytochemical and ultrastructural features between phagocytes and non-phagocytic haemocytes in C. gigas, which would provide an important clue to investigate the mechanism of phagocytosis underlying the innate immune response. Copyright © 2016 Elsevier Ltd. All rights reserved.

Signaling pathway for phagocyte priming upon encounter with apoptotic cells

PubMed Central

Ando, Yuki; Kanetani, Takuto; Hoshi, Chiharu; Nakai, Yuji

2017-01-01

The phagocytic elimination of cells undergoing apoptosis is an evolutionarily conserved innate immune mechanism for eliminating unnecessary cells. Previous studies showed an increase in the level of engulfment receptors in phagocytes after the phagocytosis of apoptotic cells, which leads to the enhancement of their phagocytic activity. However, precise mechanisms underlying this phenomenon require further clarification. We found that the pre-incubation of a Drosophila phagocyte cell line with the fragments of apoptotic cells enhanced the subsequent phagocytosis of apoptotic cells, accompanied by an augmented expression of the engulfment receptors Draper and integrin αPS3. The DNA-binding activity of the transcription repressor Tailless was transiently raised in those phagocytes, depending on two partially overlapping signal-transduction pathways for the induction of phagocytosis as well as the occurrence of engulfment. The RNAi knockdown of tailless in phagocytes abrogated the enhancement of both phagocytosis and engulfment receptor expression. Furthermore, the hemocyte-specific RNAi of tailless reduced apoptotic cell clearance in Drosophila embryos. Taken together, we propose the following mechanism for the activation of Drosophila phagocytes after an encounter with apoptotic cells: two partially overlapping signal-transduction pathways for phagocytosis are initiated; transcription repressor Tailless is activated; expression of engulfment receptors is stimulated; and phagocytic activity is enhanced. This phenomenon most likely ensures the phagocytic elimination of apoptotic cells by stimulated phagocytes and is thus considered as a mechanism to prime phagocytes in innate immunity. PMID:28325838

Ultrastructural pathology of cortical capillary pericytes in human traumatic brain oedema.

PubMed

Castejón, Orlando J

2011-01-01

In human traumatic brain oedema pericytes exhibit remarkable oedematous changes, increased vacuolar and vesicular transport, transient transpericytal channels, and tubular structures demonstrating pericyte brain barrier dysfunction. They show nuclear invaginations, actin and myosin-like filaments, and coupled interaction with endothelial cells through the macula occludens. Some pericytes display hypertrophic and necrotic changes, and phagocytic capacity. Hypertrophic pericytes induce basement membrane splitting. Degenerated pericytes exhibit lacunar enlargement of endoplasmic reticulum, dense osmiophilic bodies, glycogen granules, vacuolization, oedematous Golgi apparatus, and pleomorphic mitochondria. Certain micropinocytotic vesicles are orientated to the Golgi complex and multivesicular bodies, suggesting that pericytes play some role in oedema resolution.

Progressive kidney failure as the sole manifestation of extrapulmonary sarcoidosis.

PubMed

Sethi, Supreet; Relia, Nitin; Syal, Gaurav; Kaushik, Chhavi; Gokden, Neriman; Malik, Ahmad B

2013-09-01

Sarcoidosis is a chronic multisystem disorder characterized by an accumulation of T lymphocytes and mononuclear phagocytes, non-caseating epitheliod granulomas and derangement of normal tissue architecture in affected organs. Sarcoidosis can affect any organ system, however approximately 90% of patients with sarcoidosis have pulmonary, lymph node, cutaneous or ocular manifestations. Renal involvement in sarcoidosis is rare and clinically significant renal dysfunction even less common. We present a case of isolated renal sarcoidosis which manifested with progressively worsening renal function and hypercalcemia. A systematic diagnostic approach with pertinent laboratory studies, imaging and renal biopsy elucidated the diagnosis of renal sarcoidosis without any evidence of systemic involvement.

Flow Cytometric Analysis of Mononuclear Phagocytes in Nondiseased Human Lung and Lung-Draining Lymph Nodes.

PubMed

Desch, A Nicole; Gibbings, Sophie L; Goyal, Rajni; Kolde, Raivo; Bednarek, Joe; Bruno, Tullia; Slansky, Jill E; Jacobelli, Jordan; Mason, Robert; Ito, Yoko; Messier, Elise; Randolph, Gwendalyn J; Prabagar, Miglena; Atif, Shaikh M; Segura, Elodie; Xavier, Ramnik J; Bratton, Donna L; Janssen, William J; Henson, Peter M; Jakubzick, Claudia V

2016-03-15

The pulmonary mononuclear phagocyte system is a critical host defense mechanism composed of macrophages, monocytes, monocyte-derived cells, and dendritic cells. However, our current characterization of these cells is limited because it is derived largely from animal studies and analysis of human mononuclear phagocytes from blood and small tissue resections around tumors. Phenotypic and morphologic characterization of mononuclear phagocytes that potentially access inhaled antigens in human lungs. We acquired and analyzed pulmonary mononuclear phagocytes from fully intact nondiseased human lungs (including the major blood vessels and draining lymph nodes) obtained en bloc from 72 individual donors. Differential labeling of hematopoietic cells via intrabronchial and intravenous administration of antibodies within the same lobe was used to identify extravascular tissue-resident mononuclear phagocytes and exclude cells within the vascular lumen. Multiparameter flow cytometry was used to identify mononuclear phagocyte populations among cells labeled by each route of antibody delivery. We performed a phenotypic analysis of pulmonary mononuclear phagocytes isolated from whole nondiseased human lungs and lung-draining lymph nodes. Five pulmonary mononuclear phagocytes were observed, including macrophages, monocyte-derived cells, and dendritic cells that were phenotypically distinct from cell populations found in blood. Different mononuclear phagocytes, particularly dendritic cells, were labeled by intravascular and intrabronchial antibody delivery, countering the notion that tissue and blood mononuclear phagocytes are equivalent systems. Phenotypic descriptions of the mononuclear phagocytes in nondiseased lungs provide a precedent for comparative studies in diseased lungs and potential targets for therapeutics.

Signaling pathway for phagocyte priming upon encounter with apoptotic cells.

PubMed

Nonaka, Saori; Ando, Yuki; Kanetani, Takuto; Hoshi, Chiharu; Nakai, Yuji; Nainu, Firzan; Nagaosa, Kaz; Shiratsuchi, Akiko; Nakanishi, Yoshinobu

2017-05-12

The phagocytic elimination of cells undergoing apoptosis is an evolutionarily conserved innate immune mechanism for eliminating unnecessary cells. Previous studies showed an increase in the level of engulfment receptors in phagocytes after the phagocytosis of apoptotic cells, which leads to the enhancement of their phagocytic activity. However, precise mechanisms underlying this phenomenon require further clarification. We found that the pre-incubation of a Drosophila phagocyte cell line with the fragments of apoptotic cells enhanced the subsequent phagocytosis of apoptotic cells, accompanied by an augmented expression of the engulfment receptors Draper and integrin αPS3. The DNA-binding activity of the transcription repressor Tailless was transiently raised in those phagocytes, depending on two partially overlapping signal-transduction pathways for the induction of phagocytosis as well as the occurrence of engulfment. The RNAi knockdown of tailless in phagocytes abrogated the enhancement of both phagocytosis and engulfment receptor expression. Furthermore, the hemocyte-specific RNAi of tailless reduced apoptotic cell clearance in Drosophila embryos. Taken together, we propose the following mechanism for the activation of Drosophila phagocytes after an encounter with apoptotic cells: two partially overlapping signal-transduction pathways for phagocytosis are initiated; transcription repressor Tailless is activated; expression of engulfment receptors is stimulated; and phagocytic activity is enhanced. This phenomenon most likely ensures the phagocytic elimination of apoptotic cells by stimulated phagocytes and is thus considered as a mechanism to prime phagocytes in innate immunity. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Mononuclear phagocytes as a target, not a barrier, for drug delivery.

PubMed

Yong, Seok-Beom; Song, Yoonsung; Kim, Hyung Jin; Ain, Qurrat Ul; Kim, Yong-Hee

2017-08-10

Mononuclear phagocytes have been generally recognized as a barrier to drug delivery. Recently, a new understanding of mononuclear phagocytes (MPS) ontogeny has surfaced and their functions in disease have been unveiled, demonstrating the need for re-evaluation of perspectives on mononuclear phagocytes in drug delivery. In this review, we described mononuclear phagocyte biology and focus on their accumulation mechanisms in disease sites with explanations of monocyte heterogeneity. In the 'MPS as a barrier' section, we summarized recent studies on mechanisms to avoid phagocytosis based on two different biological principles: protein adsorption and self-recognition. In the 'MPS as a target' section, more detailed descriptions were given on mononuclear phagocyte-targeted drug delivery systems and their applications to various diseases. Collectively, we emphasize in this review that mononuclear phagocytes are potent targets for future drug delivery systems. Mononuclear phagocyte-targeted delivery systems should be created with an understanding of mononuclear phagocyte ontogeny and pathology. Each specific subset of phagocytes should be targeted differently by location and function for improved disease-drug delivery while avoiding RES clearance such as Kupffer cells and splenic macrophages. Copyright © 2017 Elsevier B.V. All rights reserved.

Molecular Determinants in Phagocyte-Bacteria Interactions.

PubMed

Kaufmann, Stefan H E; Dorhoi, Anca

2016-03-15

Phagocytes are crucial for host defense against bacterial pathogens. As first demonstrated by Metchnikoff, neutrophils and mononuclear phagocytes share the capacity to engulf, kill, and digest microbial invaders. Generally, neutrophils focus on extracellular, and mononuclear phagocytes on intracellular, pathogens. Reciprocally, extracellular pathogens often capitalize on hindering phagocytosis and killing of phagocytes, whereas intracellular bacteria frequently allow their engulfment and then block intracellular killing. As foreseen by Metchnikoff, phagocytes become highly versatile by acquiring diverse phenotypes, but still retaining some plasticity. Further, phagocytes engage in active crosstalk with parenchymal and immune cells to promote adjunctive reactions, including inflammation, tissue healing, and remodeling. This dynamic network allows the host to cope with different types of microbial invaders. Here we present an update of molecular and cellular mechanisms underlying phagocyte functions in antibacterial defense. We focus on four exemplary bacteria ranging from an opportunistic extracellular to a persistent intracellular pathogen. Copyright © 2016 Elsevier Inc. All rights reserved.

Efferocytosis and Outside-In Signaling by Cardiac Phagocytes. Links to Repair, Cellular Programming, and Intercellular Crosstalk in Heart

PubMed Central

DeBerge, Matthew; Zhang, Shuang; Glinton, Kristofor; Grigoryeva, Luba; Hussein, Islam; Vorovich, Esther; Ho, Karen; Luo, Xunrong; Thorp, Edward B.

2017-01-01

Phagocytic sensing and engulfment of dying cells and extracellular bodies initiate an intracellular signaling cascade within the phagocyte that can polarize cellular function and promote communication with neighboring non-phagocytes. Accumulating evidence links phagocytic signaling in the heart to cardiac development, adult myocardial homeostasis, and the resolution of cardiac inflammation of infectious, ischemic, and aging-associated etiology. Phagocytic clearance in the heart may be carried out by professional phagocytes, such as macrophages, and non-professional cells, including myofibrolasts and potentially epithelial cells. During cardiac development, phagocytosis initiates growth cues for early cardiac morphogenesis. In diseases of aging, including myocardial infarction, heightened levels of cell death require efficient phagocytic debridement to salvage further loss of terminally differentiated adult cardiomyocytes. Additional risk factors, including insulin resistance and other systemic risk factors, contribute to inefficient phagocytosis, altered phagocytic signaling, and delayed cardiac inflammation resolution. Under such conditions, inflammatory presentation of myocardial antigen may lead to autoimmunity and even possible rejection of transplanted heart allografts. Increased understanding of these basic mechanisms offers therapeutic opportunities. PMID:29163503

In vitro and in vivo transfection of primary phagocytes via microbubble-mediated intraphagosomal sonoporation.

PubMed

Lemmon, Jason C M; McFarland, Ryan J; Rybicka, Joanna M; Balce, Dale R; McKeown, Kyle R; Krohn, Regina M; Matsunaga, Terry O; Yates, Robin M

2011-08-31

The professional phagocytes, such as macrophages and dendritic cells, are the subject of numerous research efforts in immunology and cell biology. The use of primary phagocytes in these investigations however, are limited by their inherent resistance to transfection with DNA constructs. As a result, the use of phagocyte-like immortalized cell lines is widespread. While these cell lines are transfection permissive, they are generally regarded as poor biological substitutes for primary phagocytes. By exploiting the phagocytic machinery of primary phagocytes, we developed a non-viral method of DNA transfection of macrophages that employs intraphagosomal sonoporation mediated by internalized lipid-based microbubbles. This approach enables the transfection of primary phagocytes in vitro, with a modest, but reliable efficiency. Furthermore, this methodology was readily adapted to transfect murine peritoneal macrophages in vivo. This technology has immediate application to current research efforts and has potential for use in gene therapy and vaccination strategies. Copyright © 2011 Elsevier B.V. All rights reserved.

CD94 of tongue sole Cynoglossus semilaevis binds a wide arrange of bacteria and possesses antibacterial activity.

PubMed

Li, Xue-Peng; Hu, Yong-Hua

2016-11-01

In this study, we examined the expression patterns and the functions of the tongue sole Cynoglossus semilaevis CD94, CsCD94. CsCD94 is composed of 209 amino acid residues and shares 43.0-50.2% overall identities with known teleost CD94 sequence. CsCD94 has a C-type lectin-like domain. Expression of CsCD94 occurred in multiple tissues and was upregulated during bacterial infection. Recombinant CsCD94 (rCsCD94) exhibited apparent binding and agglutinating activities against both Gram-positive and Gram-negative bacteria in a Ca 2+ -dependent manner. Treatment of bacteria with rCsCD94 enhanced phagocytosis of the bacteria by peripheral blood leukocytes. Furthermore, incubation of rCsCD94 with bacteria reduced the survival of the bacteria in vitro. Taken together, these results indicate that rCsCD94 is a key factor in the bactericidal and phagocytic effects of tongue sole, and reveal for the first time an essential role of fish CD94 in antibacterial immunity, thereby adding insight into the function of CD94. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enhancement of anti-Aeromonas salmonicida activity in Atlantic salmon (Salmo salar) macrophages by a mannose-binding lectin

USGS Publications Warehouse

Ottinger, C.A.; Johnson, S.C.; Ewart, K.V.; Brown, L.L.; Ross, N.W.

1999-01-01

We investigated the effects of a calcium-dependent mannose-binding lectin isolated from the serum of Atlantic salmon on Aeromonassalmonicida viability and the anti-A. salmonicida activity of Atlantic salmon macrophages. In the absence of other factors, binding of this lectin at concentrations of 0.8, 4.0 and 20.0 ng ml−1 to virulent A. salmonicida failed to significantly reduce (P>0.05) cell viability. However, binding of the lectin to A. salmonicida did result in significant (P≤0.05) dose-dependent increases in phagocytosis, and bactericidal activity. Significant increases (P≤0.05) were also observed in phagocyte respiratory burst activity within the lectin concentration range of 4.0–20.0 ng ml−1 but the stimulation was not dose dependent at these lectin concentrations. At the lowest lectin concentration tested (0.32 ng ml−1), a significant decrease (P≤0.05) in respiratory burst was observed. The structure and activity of this lectin are similar to that of mammalian mannose-binding lectins, which are known to play a pivotal role in innate immunity. The presence of this lectin may be an important defense mechanism against Gram-negative bacteria such as A. salmonicida.

A Comparison of Cytotoxicity and Oxidative Stress from Welding Fumes Generated with a New Nickel-, Copper-Based Consumable versus Mild and Stainless Steel-Based Welding in RAW 264.7 Mouse Macrophages

PubMed Central

Badding, Melissa A.; Fix, Natalie R.; Antonini, James M.; Leonard, Stephen S.

2014-01-01

Welding processes that generate fumes containing toxic metals, such as hexavalent chromium (Cr(VI)), manganese (Mn), and nickel (Ni), have been implicated in lung injury, inflammation, and lung tumor promotion in animal models. While federal regulations have reduced permissible worker exposure limits to Cr(VI), this is not always practical considering that welders may work in confined spaces and exhaust ventilation may be ineffective. Thus, there has been a recent initiative to minimize the potentially hazardous components in welding materials by developing new consumables containing much less Cr(VI) and Mn. A new nickel (Ni) and copper (Cu)-based material (Ni-Cu WF) is being suggested as a safer alternative to stainless steel consumables; however, its adverse cellular effects have not been studied. This study compared the cytotoxic effects of the newly developed Ni-Cu WF with two well-characterized welding fumes, collected from gas metal arc welding using mild steel (GMA-MS) or stainless steel (GMA-SS) electrodes. RAW 264.7 mouse macrophages were exposed to the three welding fumes at two doses (50 µg/ml and 250 µg/ml) for up to 24 hours. Cell viability, reactive oxygen species (ROS) production, phagocytic function, and cytokine production were examined. The GMA-MS and GMA-SS samples were found to be more reactive in terms of ROS production compared to the Ni-Cu WF. However, the fumes from this new material were more cytotoxic, inducing cell death and mitochondrial dysfunction at a lower dose. Additionally, pre-treatment with Ni-Cu WF particles impaired the ability of cells to phagocytize E. coli, suggesting macrophage dysfunction. Thus, the toxic cellular responses to welding fumes are largely due to the metal composition. The results also suggest that reducing Cr(VI) and Mn in the generated fume by increasing the concentration of other metals (e.g., Ni, Cu) may not necessarily improve welder safety. PMID:24977413

A comparison of cytotoxicity and oxidative stress from welding fumes generated with a new nickel-, copper-based consumable versus mild and stainless steel-based welding in RAW 264.7 mouse macrophages.

PubMed

Badding, Melissa A; Fix, Natalie R; Antonini, James M; Leonard, Stephen S

2014-01-01

Welding processes that generate fumes containing toxic metals, such as hexavalent chromium (Cr(VI)), manganese (Mn), and nickel (Ni), have been implicated in lung injury, inflammation, and lung tumor promotion in animal models. While federal regulations have reduced permissible worker exposure limits to Cr(VI), this is not always practical considering that welders may work in confined spaces and exhaust ventilation may be ineffective. Thus, there has been a recent initiative to minimize the potentially hazardous components in welding materials by developing new consumables containing much less Cr(VI) and Mn. A new nickel (Ni) and copper (Cu)-based material (Ni-Cu WF) is being suggested as a safer alternative to stainless steel consumables; however, its adverse cellular effects have not been studied. This study compared the cytotoxic effects of the newly developed Ni-Cu WF with two well-characterized welding fumes, collected from gas metal arc welding using mild steel (GMA-MS) or stainless steel (GMA-SS) electrodes. RAW 264.7 mouse macrophages were exposed to the three welding fumes at two doses (50 µg/ml and 250 µg/ml) for up to 24 hours. Cell viability, reactive oxygen species (ROS) production, phagocytic function, and cytokine production were examined. The GMA-MS and GMA-SS samples were found to be more reactive in terms of ROS production compared to the Ni-Cu WF. However, the fumes from this new material were more cytotoxic, inducing cell death and mitochondrial dysfunction at a lower dose. Additionally, pre-treatment with Ni-Cu WF particles impaired the ability of cells to phagocytize E. coli, suggesting macrophage dysfunction. Thus, the toxic cellular responses to welding fumes are largely due to the metal composition. The results also suggest that reducing Cr(VI) and Mn in the generated fume by increasing the concentration of other metals (e.g., Ni, Cu) may not necessarily improve welder safety.

Cryptococcus and Phagocytes: Complex Interactions that Influence Disease Outcome

PubMed Central

Leopold Wager, Chrissy M.; Hole, Camaron R.; Wozniak, Karen L.; Wormley, Floyd L.

2016-01-01

Cryptococcus neoformans and C. gattii are fungal pathogens that cause life-threatening disease. These fungi commonly enter their host via inhalation into the lungs where they encounter resident phagocytes, including macrophages and dendritic cells, whose response has a pronounced impact on the outcome of disease. Cryptococcus has complex interactions with the resident and infiltrating innate immune cells that, ideally, result in destruction of the yeast. These phagocytic cells have pattern recognition receptors that allow recognition of specific cryptococcal cell wall and capsule components. However, Cryptococcus possesses several virulence factors including a polysaccharide capsule, melanin production and secretion of various enzymes that aid in evasion of the immune system or enhance its ability to thrive within the phagocyte. This review focuses on the intricate interactions between the cryptococci and innate phagocytic cells including discussion of manipulation and evasion strategies used by Cryptococcus, anti-cryptococcal responses by the phagocytes and approaches for targeting phagocytes for the development of novel immunotherapeutics. PMID:26903984

Altered dynamics of Candida albicans phagocytosis by macrophages and PMNs when both phagocyte subsets are present.

PubMed

Rudkin, Fiona M; Bain, Judith M; Walls, Catriona; Lewis, Leanne E; Gow, Neil A R; Erwig, Lars P

2013-10-29

An important first line of defense against Candida albicans infections is the killing of fungal cells by professional phagocytes of the innate immune system, such as polymorphonuclear cells (PMNs) and macrophages. In this study, we employed live-cell video microscopy coupled with dynamic image analysis tools to provide insights into the complexity of C. albicans phagocytosis when macrophages and PMNs were incubated with C. albicans alone and when both phagocyte subsets were present. When C. albicans cells were incubated with only one phagocyte subtype, PMNs had a lower overall phagocytic capacity than macrophages, despite engulfing fungal cells at a higher rate once fungal cells were bound to the phagocyte surface. PMNs were more susceptible to C. albicans-mediated killing than macrophages, irrespective of the number of C. albicans cells ingested. In contrast, when both phagocyte subsets were studied in coculture, the two cell types phagocytosed and cleared C. albicans at equal rates and were equally susceptible to killing by the fungus. The increase in macrophage susceptibility to C. albicans-mediated killing was a consequence of macrophages taking up a higher proportion of hyphal cells under these conditions. In the presence of both PMNs and macrophages, C. albicans yeast cells were predominantly cleared by PMNs, which migrated at a greater speed toward fungal cells and engulfed bound cells more rapidly. These observations demonstrate that the phagocytosis of fungal pathogens depends on, and is modified by, the specific phagocyte subsets present at the site of infection. Extensive work investigating fungal cell phagocytosis by macrophages and PMNs of the innate immune system has been carried out. These studies have been informative but have examined this phenomenon only when one phagocyte subset is present. The current study employed live-cell video microscopy to break down C. albicans phagocytosis into its component parts and examine the effect of a single phagocyte subset, versus a mixed phagocyte population, on these individual stages. Through this approach, we identified that the rate of fungal cell engulfment and rate of phagocyte killing altered significantly when both macrophages and PMNs were incubated in coculture with C. albicans compared to the rate of either phagocyte subset incubated alone with the fungus. This research highlights the significance of studying pathogen-host cell interactions with a combination of phagocytes in order to gain a greater understanding of the interactions that occur between cells of the host immune system in response to fungal invasion.

[Effect of general magnetotherapy on specific activity of blood phagocytes in patients with ischemic heart disease].

PubMed

Ishutin, I S; Klemenkov, S V; Lesovskaia, M I; Spiridonova, M S; Krotova, T K; Ishutin, E I; Tsyganova, O B

2007-01-01

In general magnetotherapy for patients with hyporeactive phagocytes (less than 67% from the level of normal chelicoluminescent response) the adequate level of magnetic induction is 1 mT, for patients with normoreactive phagocytes--0.5 mT and for patients with hyperreactive phagocytes (more than 133% from the level of normal chelicoluminescent response)--0.75 mT daily.

Live Candida albicans suppresses production of reactive oxygen species in phagocytes.

PubMed

Wellington, Melanie; Dolan, Kristy; Krysan, Damian J

2009-01-01

Production of reactive oxygen species (ROS) is an important aspect of phagocyte-mediated host responses. Since phagocytes play a crucial role in the host response to Candida albicans, we examined the ability of Candida to modulate phagocyte ROS production. ROS production was measured in the murine macrophage cell line J774 and in primary phagocytes using luminol-enhanced chemiluminescence. J774 cells, murine polymorphonuclear leukocytes (PMN), human monocytes, and human PMN treated with live C. albicans produced significantly less ROS than phagocytes treated with heat-killed C. albicans. Live C. albicans also suppressed ROS production in murine bone marrow-derived macrophages from C57BL/6 mice, but not from BALB/c mice. Live C. albicans also suppressed ROS in response to external stimuli. C. albicans and Candida glabrata suppressed ROS production by phagocytes, whereas Saccharomyces cerevisiae stimulated ROS production. The cell wall is the initial point of contact between Candida and phagocytes, but isolated cell walls from both heat-killed and live C. albicans stimulated ROS production. Heat-killed C. albicans has increased surface exposure of 1,3-beta-glucan, a cell wall component that can stimulate phagocytes. To determine whether surface 1,3-beta-glucan exposure accounted for the difference in ROS production, live C. albicans cells were treated with a sublethal dose of caspofungin to increase surface 1,3-beta-glucan exposure. Caspofungin-treated C. albicans was fully able to suppress ROS production, indicating that suppression of ROS overrides stimulatory signals from 1,3-beta-glucan. These studies indicate that live C. albicans actively suppresses ROS production in phagocytes in vitro, which may represent an important immune evasion mechanism.

Transcriptomic and Quantitative Proteomic Analyses Provide Insights Into the Phagocytic Killing of Hemocytes in the Oyster Crassostrea gigas

PubMed Central

Jiang, Shuai; Qiu, Limei; Wang, Lingling; Jia, Zhihao; Lv, Zhao; Wang, Mengqiang; Liu, Conghui; Xu, Jiachao; Song, Linsheng

2018-01-01

As invertebrates lack an adaptive immune system, they depend to a large extent on their innate immune system to recognize and clear invading pathogens. Although phagocytes play pivotal roles in invertebrate innate immunity, the molecular mechanisms underlying this killing remain unclear. Cells of this type from the Pacific oyster Crassostrea gigas were classified efficiently in this study via fluorescence-activated cell sorting (FACS) based on their phagocytosis of FITC-labeled latex beads. Transcriptomic and quantitative proteomic analyses revealed a series of differentially expressed genes (DEGs) and proteins present in phagocytes; of the 352 significantly high expressed proteins identified here within the phagocyte proteome, 262 corresponding genes were similarly high expressed in the transcriptome, while 140 of 205 significantly low expressed proteins within the proteome were transcriptionally low expressed. A pathway crosstalk network analysis of these significantly high expressed proteins revealed that phagocytes were highly activated in a number of antimicrobial-related biological processes, including oxidation–reduction and lysosomal proteolysis processes. A number of DEGs, including oxidase, lysosomal protease, and immune receptors, were also validated in this study using quantitative PCR, while seven lysosomal cysteine proteases, referred to as cathepsin Ls, were significantly high expressed in phagocytes. Results show that the expression level of cathepsin L protein in phagocytes [mean fluorescence intensity (MFI): 327 ± 51] was significantly higher (p < 0.01) than that in non-phagocytic hemocytes (MFI: 83 ± 26), while the cathepsin L protein was colocalized with the phagocytosed Vibrio splendidus in oyster hemocytes during this process. The results of this study collectively suggest that oyster phagocytes possess both potent oxidative killing and microbial disintegration capacities; these findings provide important insights into hemocyte phagocytic killing as a component of C. gigas innate immunity. PMID:29942306

Effects of Mycotoxins on Mucosal Microbial Infection and Related Pathogenesis

PubMed Central

Park, Seong-Hwan; Kim, Dongwook; Kim, Juil; Moon, Yuseok

2015-01-01

Mycotoxins are fungal secondary metabolites detected in many agricultural commodities and water-damaged indoor environments. Susceptibility to mucosal infectious diseases is closely associated with immune dysfunction caused by mycotoxin exposure in humans and other animals. Many mycotoxins suppress immune function by decreasing the proliferation of activated lymphocytes, impairing phagocytic function of macrophages, and suppressing cytokine production, but some induce hypersensitive responses in different dose regimes. The present review describes various mycotoxin responses to infectious pathogens that trigger mucosa-associated diseases in the gastrointestinal and respiratory tracts of humans and other animals. In particular, it focuses on the effects of mycotoxin exposure on invasion, pathogen clearance, the production of cytokines and immunoglobulins, and the prognostic implications of interactions between infectious pathogens and mycotoxin exposure. PMID:26529017

Regulation of Phagocyte Migration by Signal Regulatory Protein-Alpha Signaling.

PubMed

Alvarez-Zarate, Julian; Matlung, Hanke L; Matozaki, Takashi; Kuijpers, Taco W; Maridonneau-Parini, Isabelle; van den Berg, Timo K

2015-01-01

Signaling through the inhibitory receptor signal regulatory protein-alpha (SIRPα) controls effector functions in phagocytes. However, there are also indications that interactions between SIRPα and its ligand CD47 are involved in phagocyte transendothelial migration. We have investigated the involvement of SIRPα signaling in phagocyte migration in vitro and in vivo using mice that lack the SIRPα cytoplasmic tail. During thioglycolate-induced peritonitis in SIRPα mutant mice, both neutrophil and macrophage influx were found to occur, but to be significantly delayed. SIRPα signaling appeared to be essential for an optimal transendothelial migration and chemotaxis, and for the amoeboid type of phagocyte migration in 3-dimensional environments. These findings demonstrate, for the first time, that SIRPα signaling can directly control phagocyte migration, and this may contribute to the impaired inflammatory phenotype that has been observed in the absence of SIRPα signaling.

The Effect of Perioperative Immunonutrition on the Phagocytic Activity of Blood Platelets in Advanced Gastric Cancer Patients

PubMed Central

Kamocki, Zbigniew; Gryko, Mariusz; Kedra, Boguslaw; Kemona, Halina

2013-01-01

Background and Aims. Perioperative immunonutrition can influence the phagocytic activity of platelets in advanced gastric cancer. Methods. 51 patients with stage IV gastric cancer divided into four groups depending on the clinical status and 40 normal donors were analyzed. Patients of groups I and II underwent palliative gastrectomy. Patients of groups III and IV had exploratory laparotomy. Perioperative immunonutrition was administered as follows: group I—TPN, II—oral arginine, peripheral TPN, III—TPN preoperatively, and IV—without nutrition. The phagocytic activity of blood platelets was determined before and after nutritional therapy and was assessed by measuring the fraction of phagocytic thrombocytes (%phag) and the phagocytic index (Ixphag). Results. The percentage of phagocytizing platelets and the phagocytic index prior to and after the surgery amounted to the following: group I—1.136–1.237, P = NS, and 1.007–1.1, P = NS, respectively, II—1.111–1.25, P < 0.05, and 1.011–1.083, P < 0.05, III—1.112–1.186, P = NS, and 0.962–1.042, P = NS, and IV—1.085–0.96, P = NS, and 1.023–1.04, P = NS. Conclusions. The phagocytic activity of platelets in patients with advanced gastric cancer is significantly impaired. Perioperative immunonutrition with oral arginine-rich diet can partially improve the phagocytic activity of blood platelets. This trial is registred with Clinicaltrials.gov-NCT01704664. PMID:24363760

Scrambled Eggs: Apoptotic Cell Clearance by Non-Professional Phagocytes in the Drosophila Ovary.

PubMed

Serizier, Sandy B; McCall, Kimberly

2017-01-01

For half of a century, it has been known that non-professional phagocytes, such as fibroblasts, endothelial, and epithelial cells, are capable of efferocytosis (engulfment of apoptotic cells). Non-professional phagocytes differ from professional phagocytes in the range and efficiency of engulfment. Much of the recognition and underlying signaling machinery between non-professional and professional phagocytes is the same, but it is not known how the engulfment capacity of non-professional phagocytes is controlled. Moreover, the signaling networks involved in cell corpse recognition, engulfment, and phagosome maturation are only partially understood. The Drosophila ovary provides an excellent system to investigate the regulation of phagocytic activity by epithelial cells, a major class of non-professional phagocytes. During Drosophila oogenesis, mid-stage egg chambers undergo apoptosis of the germline in response to nutrient deprivation. Epithelial follicle cells then undergo major cell shape changes and concomitantly engulf the germline material. Our previous work has established that Draper and the integrin α-PS3/β-PS heterodimer are required in follicle cells for germline cell clearance. In addition, we have characterized phagosome maturation pathways, and found that the JNK pathway amplifies the engulfment response. In this review, we discuss recent advances on the interplay between engulfment pathways in the follicular epithelium for cell clearance in the Drosophila ovary. We also provide a comparison to apoptotic cell clearance mechanisms in C. elegans and mammals, illustrating strong conservation of efferocytosis mechanisms by non-professional phagocytes.

Pseudomonas aeruginosa flagellar motility activates the phagocyte PI3K/Akt pathway to induce phagocytic engulfment.

PubMed

Lovewell, Rustin R; Hayes, Sandra M; O'Toole, George A; Berwin, Brent

2014-04-01

Phagocytosis of the bacterial pathogen Pseudomonas aeruginosa is the primary means by which the host controls bacterially induced pneumonia during lung infection. Previous studies have identified flagellar swimming motility as a key pathogen-associated molecular pattern (PAMP) recognized by phagocytes to initiate engulfment. Correspondingly, loss of flagellar motility is observed during chronic pulmonary infection with P. aeruginosa, and this likely reflects a selection for bacteria resistant to phagocytic clearance. However, the mechanism underlying the preferential phagocytic response to motile bacteria is unknown. Here we have identified a cellular signaling pathway in alveolar macrophages and other phagocytes that is specifically activated by flagellar motility. Genetic and biochemical methods were employed to identify that phagocyte PI3K/Akt activation is required for bacterial uptake and, importantly, it is specifically activated in response to P. aeruginosa flagellar motility. Based on these observations, the second important finding that emerged from these studies is that titration of the bacterial flagellar motility results in a proportional activation state of Akt. Therefore, the Akt pathway is responsive to, and corresponds with, the degree of bacterial flagellar motility, is independent of the actin polymerization that facilitates phagocytosis, and determines the phagocytic fate of P. aeruginosa. These findings elucidate the mechanism behind motility-dependent phagocytosis of extracellular bacteria and support a model whereby phagocytic clearance exerts a selective pressure on P. aeruginosa populations in vivo, which contributes to changes in pathogenesis during infections.

Pseudomonas aeruginosa flagellar motility activates the phagocyte PI3K/Akt pathway to induce phagocytic engulfment

PubMed Central

Lovewell, Rustin R.; Hayes, Sandra M.; O'Toole, George A.

2014-01-01

Phagocytosis of the bacterial pathogen Pseudomonas aeruginosa is the primary means by which the host controls bacterially induced pneumonia during lung infection. Previous studies have identified flagellar swimming motility as a key pathogen-associated molecular pattern (PAMP) recognized by phagocytes to initiate engulfment. Correspondingly, loss of flagellar motility is observed during chronic pulmonary infection with P. aeruginosa, and this likely reflects a selection for bacteria resistant to phagocytic clearance. However, the mechanism underlying the preferential phagocytic response to motile bacteria is unknown. Here we have identified a cellular signaling pathway in alveolar macrophages and other phagocytes that is specifically activated by flagellar motility. Genetic and biochemical methods were employed to identify that phagocyte PI3K/Akt activation is required for bacterial uptake and, importantly, it is specifically activated in response to P. aeruginosa flagellar motility. Based on these observations, the second important finding that emerged from these studies is that titration of the bacterial flagellar motility results in a proportional activation state of Akt. Therefore, the Akt pathway is responsive to, and corresponds with, the degree of bacterial flagellar motility, is independent of the actin polymerization that facilitates phagocytosis, and determines the phagocytic fate of P. aeruginosa. These findings elucidate the mechanism behind motility-dependent phagocytosis of extracellular bacteria and support a model whereby phagocytic clearance exerts a selective pressure on P. aeruginosa populations in vivo, which contributes to changes in pathogenesis during infections. PMID:24487390

Scrambled Eggs: Apoptotic Cell Clearance by Non-Professional Phagocytes in the Drosophila Ovary

PubMed Central

Serizier, Sandy B.; McCall, Kimberly

2017-01-01

For half of a century, it has been known that non-professional phagocytes, such as fibroblasts, endothelial, and epithelial cells, are capable of efferocytosis (engulfment of apoptotic cells). Non-professional phagocytes differ from professional phagocytes in the range and efficiency of engulfment. Much of the recognition and underlying signaling machinery between non-professional and professional phagocytes is the same, but it is not known how the engulfment capacity of non-professional phagocytes is controlled. Moreover, the signaling networks involved in cell corpse recognition, engulfment, and phagosome maturation are only partially understood. The Drosophila ovary provides an excellent system to investigate the regulation of phagocytic activity by epithelial cells, a major class of non-professional phagocytes. During Drosophila oogenesis, mid-stage egg chambers undergo apoptosis of the germline in response to nutrient deprivation. Epithelial follicle cells then undergo major cell shape changes and concomitantly engulf the germline material. Our previous work has established that Draper and the integrin α-PS3/β-PS heterodimer are required in follicle cells for germline cell clearance. In addition, we have characterized phagosome maturation pathways, and found that the JNK pathway amplifies the engulfment response. In this review, we discuss recent advances on the interplay between engulfment pathways in the follicular epithelium for cell clearance in the Drosophila ovary. We also provide a comparison to apoptotic cell clearance mechanisms in C. elegans and mammals, illustrating strong conservation of efferocytosis mechanisms by non-professional phagocytes. PMID:29238344

Remodeling of the mononuclear phagocyte network underlies chronic inflammation and disease progression in heart failure: critical importance of the cardiosplenic axis.

PubMed

Ismahil, Mohamed Ameen; Hamid, Tariq; Bansal, Shyam S; Patel, Bindiya; Kingery, Justin R; Prabhu, Sumanth D

2014-01-17

The role of mononuclear phagocytes in chronic heart failure (HF) is unknown. Our aim was to delineate monocyte, macrophage, and dendritic cell trafficking in HF and define the contribution of the spleen to cardiac remodeling. We evaluated C57Bl/6 mice with chronic HF 8 weeks after coronary ligation. As compared with sham-operated controls, HF mice exhibited: (1) increased proinflammatory CD11b+ F4/80+ CD206- macrophages and CD11b+ F4/80+ Gr-1(hi) monocytes in the heart and peripheral blood, respectively, and reduced CD11b+ F4/80+ Gr-1(hi) monocytes in the spleen; (2) significantly increased CD11c+ B220- classical dendritic cells and CD11c+ low)B220+ plasmacytoid dendritic cells in both the heart and spleen, and increased classic dendritic cells and plasmacytoid dendritic cells in peripheral blood and bone marrow, respectively; (3) increased CD4+ helper and CD8+ cytotoxic T-cells in the spleen; and (4) profound splenic remodeling with abundant white pulp follicles, markedly increased size of the marginal zone and germinal centers, and increased expression of alarmins. Splenectomy in mice with established HF reversed pathological cardiac remodeling and inflammation. Splenocytes adoptively transferred from mice with HF, but not from sham-operated mice, homed to the heart and induced long-term left ventricular dilatation, dysfunction, and fibrosis in naive recipients. Recipient mice also exhibited monocyte activation and splenic remodeling similar to HF mice. Activation of mononuclear phagocytes is central to the progression of cardiac remodeling in HF, and heightened antigen processing in the spleen plays a critical role in this process. Splenocytes (presumably splenic monocytes and dendritic cells) promote immune-mediated injurious responses in the failing heart and retain this memory on adoptive transfer.

Step-wise loss of bacterial flagellar torsion confers progressive phagocytic evasion.

PubMed

Lovewell, Rustin R; Collins, Ryan M; Acker, Julie L; O'Toole, George A; Wargo, Matthew J; Berwin, Brent

2011-09-01

Phagocytosis of bacteria by innate immune cells is a primary method of bacterial clearance during infection. However, the mechanisms by which the host cell recognizes bacteria and consequentially initiates phagocytosis are largely unclear. Previous studies of the bacterium Pseudomonas aeruginosa have indicated that bacterial flagella and flagellar motility play an important role in colonization of the host and, importantly, that loss of flagellar motility enables phagocytic evasion. Here we use molecular, cellular, and genetic methods to provide the first formal evidence that phagocytic cells recognize bacterial motility rather than flagella and initiate phagocytosis in response to this motility. We demonstrate that deletion of genes coding for the flagellar stator complex, which results in non-swimming bacteria that retain an initial flagellar structure, confers resistance to phagocytic binding and ingestion in several species of the gamma proteobacterial group of Gram-negative bacteria, indicative of a shared strategy for phagocytic evasion. Furthermore, we show for the first time that susceptibility to phagocytosis in swimming bacteria is proportional to mot gene function and, consequently, flagellar rotation since complementary genetically- and biochemically-modulated incremental decreases in flagellar motility result in corresponding and proportional phagocytic evasion. These findings identify that phagocytic cells respond to flagellar movement, which represents a novel mechanism for non-opsonized phagocytic recognition of pathogenic bacteria.

Step-Wise Loss of Bacterial Flagellar Torsion Confers Progressive Phagocytic Evasion

PubMed Central

Lovewell, Rustin R.; Collins, Ryan M.; Acker, Julie L.; O'Toole, George A.; Wargo, Matthew J.; Berwin, Brent

2011-01-01

Phagocytosis of bacteria by innate immune cells is a primary method of bacterial clearance during infection. However, the mechanisms by which the host cell recognizes bacteria and consequentially initiates phagocytosis are largely unclear. Previous studies of the bacterium Pseudomonas aeruginosa have indicated that bacterial flagella and flagellar motility play an important role in colonization of the host and, importantly, that loss of flagellar motility enables phagocytic evasion. Here we use molecular, cellular, and genetic methods to provide the first formal evidence that phagocytic cells recognize bacterial motility rather than flagella and initiate phagocytosis in response to this motility. We demonstrate that deletion of genes coding for the flagellar stator complex, which results in non-swimming bacteria that retain an initial flagellar structure, confers resistance to phagocytic binding and ingestion in several species of the gamma proteobacterial group of Gram-negative bacteria, indicative of a shared strategy for phagocytic evasion. Furthermore, we show for the first time that susceptibility to phagocytosis in swimming bacteria is proportional to mot gene function and, consequently, flagellar rotation since complementary genetically- and biochemically-modulated incremental decreases in flagellar motility result in corresponding and proportional phagocytic evasion. These findings identify that phagocytic cells respond to flagellar movement, which represents a novel mechanism for non-opsonized phagocytic recognition of pathogenic bacteria. PMID:21949654

B-1 phagocytes: the myeloid face of B-1 cells.

PubMed

Popi, Ana Flavia

2015-12-01

The relationship between malignant B cells and macrophages has long been established. Furthermore, evolutionary studies have demonstrated that B cells from early vertebrates have both phagocytic and antibody production capabilities. In addition to their lymphoid nature, B-1 cells retain several myeloid characteristics. Various reports have demonstrated that B-1 cells can differentiate into phagocytes. However, descriptions of B-1 cells as a novel phagocyte cell member are rarely found in the literature. This review aims to present the available data regarding B-1 cell-derived phagocytes and also discusses how their existence might be relevant to hematopoiesis and immune responses. © 2015 New York Academy of Sciences.

Bacteria-induced phagocyte secondary necrosis as a pathogenicity mechanism.

PubMed

Silva, Manuel T

2010-11-01

Triggering of phagocyte apoptosis is a major virulence mechanism used by some successful bacterial pathogens. A central issue in the apoptotic death context is that fully developed apoptosis results in necrotic cell autolysis (secondary necrosis) with release of harmful cell components. In multicellular animals, this occurs when apoptosing cells are not removed by scavengers, mainly macrophages. Secondary necrotic lysis of neutrophils and macrophages may occur in infection when extensive phagocyte apoptosis is induced by bacterial cytotoxins and removal of apoptosing phagocytes is defective because the apoptotic process exceeds the available scavenging capacity or targets macrophages directly. Induction of phagocyte secondary necrosis is an important pathogenic mechanism, as it combines the pathogen evasion from phagocyte antimicrobial activities and the release of highly cytotoxic molecules, particularly of neutrophil origin, such as neutrophil elastase. This pathogenicity mechanism therefore promotes the unrestricted multiplication of the pathogen and contributes directly to the pathology of several necrotizing infections, where extensive apoptosis and necrosis of macrophages and neutrophils are present. Here, examples of necrotizing infectious diseases, where phagocyte secondary necrosis is implicated, are reviewed.

Streptococcus pyogenes CAMP factor attenuates phagocytic activity of RAW 264.7 cells.

PubMed

Kurosawa, Mie; Oda, Masataka; Domon, Hisanori; Saitoh, Issei; Hayasaki, Haruaki; Terao, Yutaka

2016-02-01

Streptococcus pyogenes produces molecules that inhibit the function of human immune system, thus allowing the pathogen to grow and spread in tissues. It is known that S. pyogenes CAMP factor increases erythrocytosis induced by Staphylococcus aureus β-hemolysin. However, the effects of CAMP factor for immune cells are unclear. In this study, we investigated the effects of CAMP factor to macrophages. Western blotting analysis demonstrated that all examined strains expressed CAMP factor protein. In the presence of calcium or magnesium ion, CAMP factor was significantly released in the supernatant. In addition, both culture supernatant from S. pyogenes strain SSI-9 and recombinant CAMP factor dose-dependently induced vacuolation in RAW 264.7 cells, but the culture supernatant from Δcfa isogenic mutant strain did not. CAMP factor formed oligomers in RAW 264.7 cells in a time-dependent manner. CAMP factor suppressed cell proliferation via G2 phase cell cycle arrest without inducing cell death. Furthermore, CAMP factor reduced the uptake of S. pyogenes and phagocytic activity indicator by RAW 264.7 cells. These results suggest that CAMP factor works as a macrophage dysfunction factor. Therefore, we conclude that CAMP factor allows S. pyogenes to escape the host immune system, and contribute to the spread of streptococcal infection. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Morin hydrate augments phagocytosis mechanism and inhibits LPS induced autophagic signaling in murine macrophage.

PubMed

Jakhar, Rekha; Paul, Souren; Chauhan, Anil Kumar; Kang, Sun Chul

2014-10-01

Morin, a natural flavonoid that is the primary bioactive constituent of the family Moraceae, has been found to be associated with many therapeutic properties. In this study, we evaluated the immunomodulatory activities of increasing concentration of morin hydrate in vitro. Three different concentrations of morin hydrate (5, 10, and 15μM) were used to evaluate their effect on splenocyte proliferation, phagocytic activity of macrophages, cytokine secretion and complement inhibition. We also evaluated the role of morin hydrate on lipopolysaccharide (LPS) induced autophagy. Our study demonstrated that morin hydrate elicited a significant increase in splenocyte proliferation, phagocytic capacity and suppressed the production of cytokines and nitric oxide in activated macrophages. Humoral immunity measured by anti-complement activity showed an increase in inhibition of the complement system after the addition of morin hydrate, where morin hydrate at 15μM concentration induced a significant inhibition. Depending on our results, we can also conclude that morin hydrate protects macrophages from LPS induced autophagic cell death. Our findings suggest that morin hydrate represents a structurally diverse class of flavonoid and this structural variability can profoundly affect its cell-type specificity and its biological activities. Supplementation of immune cells with morin hydrate has an upregulating and immunoprotective effect that shows potential as a countermeasure to the immune dysfunction and suggests an interesting use in inflammation related diseases. Copyright © 2014 Elsevier B.V. All rights reserved.

Regulation of Phagocyte Migration by Signal Regulatory Protein-Alpha Signaling

PubMed Central

Alvarez-Zarate, Julian; Matlung, Hanke L.; Matozaki, Takashi; Kuijpers, Taco W.; Maridonneau-Parini, Isabelle; van den Berg, Timo K.

2015-01-01

Signaling through the inhibitory receptor signal regulatory protein-alpha (SIRPα) controls effector functions in phagocytes. However, there are also indications that interactions between SIRPα and its ligand CD47 are involved in phagocyte transendothelial migration. We have investigated the involvement of SIRPα signaling in phagocyte migration in vitro and in vivo using mice that lack the SIRPα cytoplasmic tail. During thioglycolate-induced peritonitis in SIRPα mutant mice, both neutrophil and macrophage influx were found to occur, but to be significantly delayed. SIRPα signaling appeared to be essential for an optimal transendothelial migration and chemotaxis, and for the amoeboid type of phagocyte migration in 3-dimensional environments. These findings demonstrate, for the first time, that SIRPα signaling can directly control phagocyte migration, and this may contribute to the impaired inflammatory phenotype that has been observed in the absence of SIRPα signaling. PMID:26057870

High temperature affects the phagocytic activity of human peripheral blood mononuclear cells.

PubMed

Djaldetti, Meir; Bessler, Hanna

2015-10-01

The ability for engulfment of pathogens and inert particles is the key hallmark of the phagocytic cells. Phagocytes play a significant role in the modulation of local or extended inflammation. Since fever activates a number of factors linked with the immune response it was the goal of this study to examine the in vitro effect of hyperthermia on the phagocytic capacity, the number of phagocytic cells and the viability of human peripheral blood mononuclear cells (PBMC) at 37 and 40°C. PBMC were incubated with 0.8 μm polysterene latex beads, for 2 hours at 37 and 40°C. The number of phagocytic cells, and that of latex particles internalized by each individual cell was counted with a light microscope. In addition, the percentage of viable cells and the number of active metabolic cells was evaluated. A temperature of 40°C significantly increased the number of phagocytic cells and the phagocytic index by 41 and 37% respectively, as compared to cells incubated at 37°C. While the number of vital cells (trypan blue test) did not differ statistically at both temperatures, the number of active metabolic cells (XTT test) after 2 h of incubation at 40°C was 17% higher as compared with that at 37°C. However, the number of active metabolic cells after 24 h of incubation at 40°C was 51% lower compared with cells incubated at 37°C. The increased phagocytic capacity of human peripheral blood monocytes at high temperature further enlightens the immunomodulatory effect of fever in the immune responses during inflammation.

Mechanisms of failed apoptotic cell clearance by phagocyte subsets in cardiovascular disease

PubMed Central

2013-01-01

Recent evidence in humans indicate that defective phagocytic clearance of dying cells is linked to progression of advanced atherosclerotic lesions, the precursor to atherothrombosis, ischemic heart disease, and leading cause of death in the industrialized world. During atherogenesis, apoptotic cell turnover in the vascular wall is counterbalanced by neighboring phagocytes with high clearance efficiency, thereby limiting cellularity and maintaining lesion integrity. However, as lesions mature, phagocytic removal of apoptotic cells (efferocytosis) becomes defective, leading to secondary necrosis, expansion of plaque necrotic cores, and susceptibility to rupture. Recent genetic causation studies in experimental rodents have implicated key molecular regulators of efferocytosis in atherosclerotic progression. These include MER tyrosine kinase (MERTK), milk fat globule-EGF factor 8 (MFGE8), and complement C1q. At the cellular level, atheromata are infiltrated by a heterogenous population of professional phagocytes, comprised of monocytes, differentiated macrophages, and CD11c+ dendritic-like cells. Each cell type is characterized by disparate clearance efficiencies and varying activities of key phagocytic signaling molecules. It is in this context that we outline a working model whereby plaque necrosis and destabilization is jointly promoted by (1) direct inhibition of core phagocytic signaling pathways and (2) expansion of phagocyte subsets with poor clearance capacity. Towards identifying targets for promoting efficient apoptotic cell clearance and resolving inflammation in atherosclerosis and during ischemic heart disease and post myocardial infarction, this review will discuss potential in vivo suppressors of efferocytosis at each stage of clearance and how these putative interventional targets may differentially affect uptake at the level of vascular phagocyte subsets. PMID:20552278

2-Chlorohexadecanoic acid induces ER stress and mitochondrial dysfunction in brain microvascular endothelial cells.

PubMed

Bernhart, Eva; Kogelnik, Nora; Prasch, Jürgen; Gottschalk, Benjamin; Goeritzer, Madeleine; Depaoli, Maria Rosa; Reicher, Helga; Nusshold, Christoph; Plastira, Ioanna; Hammer, Astrid; Fauler, Günter; Malli, Roland; Graier, Wolfgang F; Malle, Ernst; Sattler, Wolfgang

2018-05-01

Peripheral leukocytes induce blood-brain barrier (BBB) dysfunction through the release of cytotoxic mediators. These include hypochlorous acid (HOCl) that is formed via the myeloperoxidase-H 2 O 2 -chloride system of activated phagocytes. HOCl targets the endogenous pool of ether phospholipids (plasmalogens) generating chlorinated inflammatory mediators like e.g. 2-chlorohexadecanal and its conversion product 2-chlorohexadecanoic acid (2-ClHA). In the cerebrovasculature these compounds inflict damage to brain microvascular endothelial cells (BMVEC) that form the morphological basis of the BBB. To follow subcellular trafficking of 2-ClHA we synthesized a 'clickable' alkyne derivative (2-ClHyA) that phenocopied the biological activity of the parent compound. Confocal and superresolution structured illumination microscopy revealed accumulation of 2-ClHyA in the endoplasmic reticulum (ER) and mitochondria of human BMVEC (hCMEC/D3 cell line). 2-ClHA and its alkyne analogue interfered with protein palmitoylation, induced ER-stress markers, reduced the ER ATP content, and activated transcription and secretion of interleukin (IL)-6 as well as IL-8. 2-ClHA disrupted the mitochondrial membrane potential and induced procaspase-3 and PARP cleavage. The protein kinase R-like ER kinase (PERK) inhibitor GSK2606414 suppressed 2-ClHA-mediated activating transcription factor 4 synthesis and IL-6/8 secretion, but showed no effect on endothelial barrier dysfunction and cleavage of procaspase-3. Our data indicate that 2-ClHA induces potent lipotoxic responses in brain endothelial cells and could have implications in inflammation-induced BBB dysfunction. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Neuropathology of White Matter Lesions, Blood-Brain Barrier Dysfunction, and Dementia.

PubMed

Hainsworth, Atticus H; Minett, Thais; Andoh, Joycelyn; Forster, Gillian; Bhide, Ishaan; Barrick, Thomas R; Elderfield, Kay; Jeevahan, Jamuna; Markus, Hugh S; Bridges, Leslie R

2017-10-01

We tested whether blood-brain barrier dysfunction in subcortical white matter is associated with white matter abnormalities or risk of clinical dementia in older people (n=126; mean age 86.4, SD: 7.7 years) in the MRC CFAS (Medical Research Council Cognitive Function and Ageing Study). Using digital pathology, we quantified blood-brain barrier dysfunction (defined by immunohistochemical labeling for the plasma marker fibrinogen). This was assessed within subcortical white matter tissue samples harvested from postmortem T 2 magnetic resonance imaging (MRI)-detected white matter hyperintensities, from normal-appearing white matter (distant from coexistent MRI-defined hyperintensities), and from equivalent areas in MRI normal brains. Histopathologic lesions were defined using a marker for phagocytic microglia (CD68, clone PGM1). Extent of fibrinogen labeling was not significantly associated with white matter abnormalities defined either by MRI (odds ratio, 0.90; 95% confidence interval, 0.79-1.03; P =0.130) or by histopathology (odds ratio, 0.93; 95% confidence interval, 0.77-1.12; P =0.452). Among participants with normal MRI (no detectable white matter hyperintensities), increased fibrinogen was significantly related to decreased risk of clinical dementia (odds ratio, 0.74; 95% confidence interval, 0.58-0.94; P =0.013). Among participants with histological lesions, increased fibrinogen was related to increased risk of dementia (odds ratio, 2.26; 95% confidence interval, 1.25-4.08; P =0.007). Our data suggest that some degree of blood-brain barrier dysfunction is common in older people and that this may be related to clinical dementia risk, additional to standard MRI biomarkers. © 2017 American Heart Association, Inc.

Phagocytes in cell suspensions of human colon mucosa.

PubMed Central

Beeken, W; Northwood, I; Beliveau, C; Gump, D

1987-01-01

Because little is known of the phagocytes of the human colon we enumerated these cells in mucosal suspensions and studied their phagocytic activity. Phagocyte rich suspensions were made by EDTA collagenase dissociation followed by elutriation centrifugation. Phagocytosis was evaluated by measuring cellular radioactivity after incubation of phagocytes with 3H-adenine labelled E coli ON2 and checked microscopically. Dissociation of normal mucosa from colorectal neoplasms yielded means of 1.9 X 10(6) eosinophils, 1.4 X 10(6) macrophages and 2 X 10(5) neutrophils per gram of mucosa. Visually normal mucosa of inflammatory states yielded 2.2 X 10(6) eosinophils, 2.3 X 10(6) macrophages and 7 X 10(5) neutrophils per gram of mucosa. Phagocyte rich suspensions of normal mucosa from tumour patients phagocytosed 21.8% of a pool of opsonised tritiated E coli ON2 and by microscopy 100% of mucosal neutrophils ingested bacteria, 83% of eosinophils were phagocytic, and 53% of macrophages contained bacteria. These results suggest that in the human colonic mucosa, the eosinophil is more abundant than the macrophage and the per cent of those cells exhibiting phagocytosis is intermediate between that of the macrophage and the neutrophil. Thus these three types of cells are actively phagocytic and share the potential for a major role in host defence against invasive enteric bacteria. PMID:3666566

Continued clearance of apoptotic cells critically depends on the phagocyte Ucp2 protein

PubMed Central

Park, Daeho; Han, Claudia; Elliott, Michael R.; Kinchen, Jason M.; Trampont, Paul C.; Das, Soumita; Collins, Sheila; Lysiak, Jeffrey J.; Hoehn, Kyle L.; Ravichandran, Kodi S.

2012-01-01

Rapid and efficient removal of apoptotic cells by phagocytes plays a key role during development, tissue homeostasis, and in controlling immune responses1–5. An important feature of efficient clearance is the capacity of a single phagocyte to ingest multiple apoptotic cells successively, and to process the increased load of corpse-derived cellular material6–9. However, factors that influence sustained phagocytic capacity or how they in turn influence continued clearance by phagocytes are not known. Here we identify that the ability of a phagocyte to control its mitochondrial membrane potential is a critical factor in the capacity of a phagocyte to engulf apoptotic cells. Changing the phagocyte mitochondrial membrane potential (genetically or pharmacologically) significantly affected phagocytosis, with lower potential enhancing engulfment and higher membrane potential inhibiting uptake. We then identified that Ucp2, a mitochondrial membrane protein that acts to lower the mitochondrial membrane potential10–12, is upregulated in phagocytes engulfing apoptotic cells (but not synthetic targets, bacteria, or yeast). Loss of Ucp2 limited the capacity of phagocytes to continually ingest apoptotic cells, while overexpression of Ucp2 increased the capacity for engulfment and the ability to engulf multiple apoptotic cells. Mutational and pharmacological inhibition of Ucp2 uncoupling activity reversed the positive effect of Ucp2 on engulfment capacity, suggesting a direct role for Ucp2-mediated mitochondrial function in phagocytosis. Macrophages from Ucp2-deficient mice13, 14 were impaired in their capacity to engulf apoptotic cells in vitro, and Ucp2-deficient mice displayed profound in vivo defects in clearing dying cells in the thymus and the testes. Collectively, these data suggest that phagocytes alter the mitochondrial membrane potential during engulfment to regulate uptake of sequential apoptotic cells, and that Ucp2 is a key molecular determinant of this step in vivo. Since Ucp2 function has also been linked to metabolic diseases and atherosclerosis14–16, these data identifying a new role for Ucp2 in regulating apoptotic cell clearance may provide additional insights toward understanding the complex etiology and pathogenesis of these diseases. PMID:21857682

Inhibitory Effect of the Ethanol Extract of a Rice Bran Mixture Comprising Angelica gigas, Cnidium officinale, Artemisia princeps, and Camellia sinensis on Brucella abortus Uptake by Professional and Nonprofessional Phagocytes.

PubMed

Hop, Huynh Tan; Arayan, Lauren Togonon; Reyes, Alisha Wehdnesday Bernardo; Huy, Tran Xuan Ngoc; Baek, Eun Jin; Min, WonGi; Lee, Hu Jang; Lee, Chun Hee; Rhee, Man Hee; Kim, Suk

2017-10-28

In this study, we evaluated the inhibitory effect of a rice bran mixture extract (RBE) on Brucella abortus pathogenesis in professional (RAW 264.7) and nonprofessional (HeLa) phagocytes. We fermented the rice bran mixture and then extracted it with 50% ethanol followed by gas chromatography-mass spectrometry to identify the components in RBE. Our results clearly showed that RBE caused a significant reduction in the adherence of B. abortus in both cell lines. Furthermore, analysis of phagocytic signaling proteins by western blot assay revealed that RBE pretreatment resulted in inhibition of phosphorylation of JNK, ERK, and p38, leading to decline of internalization compared with the controls. Additionally, the intensity of F-actin observed by fluorescence microscopy and FACS was remarkably reduced in RBE-pretreated cells compared with control cells. However, the intracellular replication of B. abortus within phagocytes was not affected by RBE. Taken together, these findings suggest that the phagocytic receptor blocking and suppressive effects of RBE on the MAPK-linked phagocytic signaling pathway could negatively affect the invasion of B. abortus into phagocytes.

Clearance of Dying Cells by Phagocytes: Mechanisms and Implications for Disease Pathogenesis.

PubMed

Fond, Aaron M; Ravichandran, Kodi S

The efficient clearance of apoptotic cells is an evolutionarily conserved process crucial for homeostasis in multicellular organisms. The clearance involves a series of steps that ultimately facilitates the recognition of the apoptotic cell by the phagocytes and the subsequent uptake and processing of the corpse. These steps include the phagocyte sensing of "find-me" signals released by the apoptotic cell, recognizing "eat-me" signals displayed on the apoptotic cell surface, and then intracellular signaling within the phagocyte to mediate phagocytic cup formation around the corpse and corpse internalization, and the processing of the ingested contents. The engulfment of apoptotic cells by phagocytes not only eliminates debris from tissues but also produces an anti-inflammatory response that suppresses local tissue inflammation. Conversely, impaired corpse clearance can result in loss of immune tolerance and the development of various inflammation-associated disorders such as autoimmunity, atherosclerosis, and airway inflammation but can also affect cancer progression. Recent studies suggest that the clearance process can also influence antitumor immune responses. In this review, we will discuss how apoptotic cells interact with their engulfing phagocytes to generate important immune responses, and how modulation of such responses can influence pathology.

Live Candida albicans Suppresses Production of Reactive Oxygen Species in Phagocytes▿ †

PubMed Central

Wellington, Melanie; Dolan, Kristy; Krysan, Damian J.

2009-01-01

Production of reactive oxygen species (ROS) is an important aspect of phagocyte-mediated host responses. Since phagocytes play a crucial role in the host response to Candida albicans, we examined the ability of Candida to modulate phagocyte ROS production. ROS production was measured in the murine macrophage cell line J774 and in primary phagocytes using luminol-enhanced chemiluminescence. J774 cells, murine polymorphonuclear leukocytes (PMN), human monocytes, and human PMN treated with live C. albicans produced significantly less ROS than phagocytes treated with heat-killed C. albicans. Live C. albicans also suppressed ROS production in murine bone marrow-derived macrophages from C57BL/6 mice, but not from BALB/c mice. Live C. albicans also suppressed ROS in response to external stimuli. C. albicans and Candida glabrata suppressed ROS production by phagocytes, whereas Saccharomyces cerevisiae stimulated ROS production. The cell wall is the initial point of contact between Candida and phagocytes, but isolated cell walls from both heat-killed and live C. albicans stimulated ROS production. Heat-killed C. albicans has increased surface exposure of 1,3-β-glucan, a cell wall component that can stimulate phagocytes. To determine whether surface 1,3-β-glucan exposure accounted for the difference in ROS production, live C. albicans cells were treated with a sublethal dose of caspofungin to increase surface 1,3-β-glucan exposure. Caspofungin-treated C. albicans was fully able to suppress ROS production, indicating that suppression of ROS overrides stimulatory signals from 1,3-β-glucan. These studies indicate that live C. albicans actively suppresses ROS production in phagocytes in vitro, which may represent an important immune evasion mechanism. PMID:18981256

Development of an In Vitro Model for the Multi-Parametric Quantification of the Cellular Interactions between Candida Yeasts and Phagocytes

PubMed Central

Noël, Thierry

2012-01-01

We developed a new in vitro model for a multi-parameter characterization of the time course interaction of Candida fungal cells with J774 murine macrophages and human neutrophils, based on the use of combined microscopy, fluorometry, flow cytometry and viability assays. Using fluorochromes specific to phagocytes and yeasts, we could accurately quantify various parameters simultaneously in a single infection experiment: at the individual cell level, we measured the association of phagocytes to fungal cells and phagocyte survival, and monitored in parallel the overall phagocytosis process by measuring the part of ingested fungal cells among the total fungal biomass that changed over time. Candida albicans, C. glabrata, and C. lusitaniae were used as a proof of concept: they exhibited species-specific differences in their association rate with phagocytes. The fungal biomass uptaken by the phagocytes differed significantly according to the Candida species. The measure of the survival of fungal and immune cells during the interaction showed that C. albicans was the more aggressive yeast in vitro, destroying the vast majority of the phagocytes within five hours. All three species of Candida were able to survive and to escape macrophage phagocytosis either by the intraphagocytic yeast-to-hyphae transition (C. albicans) and the fungal cell multiplication until phagocytes burst (C. glabrata, C. lusitaniae), or by the avoidance of phagocytosis (C. lusitaniae). We demonstrated that our model was sensitive enough to quantify small variations of the parameters of the interaction. The method has been conceived to be amenable to the high-throughput screening of mutants in order to unravel the molecular mechanisms involved in the interaction between yeasts and host phagocytes. PMID:22479332

Mechanisms of mononuclear phagocyte recruitment in Alzheimer's disease.

PubMed

Hickman, Suzanne E; El Khoury, Joseph

2010-04-01

Alzheimer's disease (AD) is associated with a significant neuroinflammatory component. Mononuclear phagocytes including monocytes and microglia are the principal cells involved, and they accumulate at perivascular sites of beta-amyloid (Abeta) deposition and in senile plaques. Recent evidence suggests that mononuclear phagocyte accumulation in the AD brain is dependent on chemokines. CCL2, a major monocyte chemokine, is upregulated in the AD brain. Interaction of CCL2 with its receptor CCR2 regulates mononuclear phagocyte accumulation in a mouse model of AD. CCR2 deficiency leads to lower mononuclear phagocyte accumulation and is associated with higher brain Abeta levels, specifically around blood vessels, suggesting that monocytes accumulate at sites of Abeta deposition in an initial attempt to clear these deposits and stop or delay their neurotoxic effects. Indeed, enhancing mononuclear phagocyte accumulation delays progression of AD. Here we review the mechanisms of mononuclear phagocyte accumulation in AD and discuss the potential roles of additional chemokines and their receptors in this process. We also propose a multi-step model for recruitment of mononuclear phagocytes into the brain. The first step involves egress of monocyte/microglial precursors from the bone marrow into the blood. The second step is crossing the blood-brain barrier to the perivascular areas and into the brain parenchyma. The final step includes movement of monocytes/microglia from areas of the brain that lack any amyloid deposition to senile plaques. Understanding the mechanism of recruitment of mononuclear phagocytes to the AD brain is necessary to further understand the role of these cells in the pathogenesis of AD and to identify any potential therapeutic use of these cells for the treatment of this disease.

Polymeric micellar nanoplatforms for Fenton reaction as a new class of antibacterial agents.

PubMed

Park, Seong-Cheol; Kim, Nam-Hong; Yang, Wonseok; Nah, Jae-Woon; Jang, Mi-Kyeong; Lee, Dongwon

2016-01-10

Reactive oxygen species (ROS) produced by host phagocytes exert antibacterial action against a variety of pathogens and ROS-induced oxidative stress is the governing mechanism for the antibacterial activity of major bactericidal antibiotics. In particular, hydroxyl radical is a strong and nonselective oxidant which can damage biomolecules such as DNA, proteins and lipids. Ferrous ion is known to convert mild oxidant hydrogen peroxide (H2O2) into highly reactive and toxic hydroxyl radicals, referred to as Fenton reaction. Herein, we report a new class of antibacterial agents based on Fenton reaction-performing nanostructures, composed of H2O2-generating polymer (PCAE) and iron-containing ferrocene. Amphiphilic PCAE was designed to incorporate H2O2-generating cinnamaldehyde through acid-cleavable linkages and self-assemble to form thermodynamically stable micelles which could encapsulate ferrocene in their hydrophobic core. All the experiments in vitro display that ferrocene-loaded PCAE micelles produce hydroxyl radicals to kill Escherichia coli and Pseudomonas aeruginosa through membrane damages. Intraperitoneally injected ferrocene-loaded PCAE micelles significantly reduced the lung damages and therefore increased the survival rate of mice infected with drug resistant P. aeruginosa. Given their potent antibacterial activity, ferrocene-loaded PCAE micelles hold great potential as a new class of ROS-manipulating antibacterial agents. Copyright © 2015 Elsevier B.V. All rights reserved.

Characterization of phagocytic hemocytes in Ornithodoros moubata (Acari: Ixodidae).

PubMed

Inoue, N; Hanada, K; Tsuji, N; Igarashi, I; Nagasawa, H; Mikami, T; Fujisaki, K

2001-07-01

Effects of fetal bovine serum (FBS) and complement on phagocytic activity in Ornithodaros moubata (Murray 1877) hemocytes and protease activity in the hemocytes were examined. At least three morphologically different cell types, granulocytes, plasmatocytes, and prohemocytes, were detected in hemolymph of O. moubata, and granulocytes and plasmatocytes showed phagocytic activity. FBS altered phagocytic activity of granulocytes, and complement affected phagocytic activity of plasmatocytes. Ticks were inoculated with fluorescent polystyrene beads in combination with FBS or complement. The average number of beads in granulocytes was significantly higher in the FBS injected group than the control (P < 0.01). The percentage of bead-ingesting plasmatocytes in complement inoculated ticks was significantly lower than that in heat-inactivated complement inoculated and control ticks (P < 0.05). Proteases of tick hemocytes localized in small granules in the cytoplasm not only in phagocytic hemocytes but also in prohemocytes. Results suggested modulation of tick hemocyte function through serum components, and digestion of phagocytosed foreign bodies in the hemocytes.

Altered Dynamics of Candida albicans Phagocytosis by Macrophages and PMNs When Both Phagocyte Subsets Are Present

PubMed Central

Rudkin, Fiona M.; Bain, Judith M.; Walls, Catriona; Lewis, Leanne E.; Gow, Neil A. R.; Erwig, Lars P.

2013-01-01

ABSTRACT An important first line of defense against Candida albicans infections is the killing of fungal cells by professional phagocytes of the innate immune system, such as polymorphonuclear cells (PMNs) and macrophages. In this study, we employed live-cell video microscopy coupled with dynamic image analysis tools to provide insights into the complexity of C. albicans phagocytosis when macrophages and PMNs were incubated with C. albicans alone and when both phagocyte subsets were present. When C. albicans cells were incubated with only one phagocyte subtype, PMNs had a lower overall phagocytic capacity than macrophages, despite engulfing fungal cells at a higher rate once fungal cells were bound to the phagocyte surface. PMNs were more susceptible to C. albicans-mediated killing than macrophages, irrespective of the number of C. albicans cells ingested. In contrast, when both phagocyte subsets were studied in coculture, the two cell types phagocytosed and cleared C. albicans at equal rates and were equally susceptible to killing by the fungus. The increase in macrophage susceptibility to C. albicans-mediated killing was a consequence of macrophages taking up a higher proportion of hyphal cells under these conditions. In the presence of both PMNs and macrophages, C. albicans yeast cells were predominantly cleared by PMNs, which migrated at a greater speed toward fungal cells and engulfed bound cells more rapidly. These observations demonstrate that the phagocytosis of fungal pathogens depends on, and is modified by, the specific phagocyte subsets present at the site of infection. PMID:24169578

21 CFR 1240.10 - Effective bactericidal treatment.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Effective bactericidal treatment. 1240.10 Section... DISEASES General Provisions § 1240.10 Effective bactericidal treatment. Whenever, under the provisions of this part, bactericidal treatment is required, it shall be accomplished by one or more of the following...

In vivo and in vitro phagocytosis of Leishmania (Leishmania) amazonensis promastigotes by B-1 cells.

PubMed

Geraldo, M M; Costa, C R; Barbosa, F M C; Vivanco, B C; Gonzaga, W F K M; Novaes E Brito, R R; Popi, A F; Lopes, J D; Xander, P

2016-06-01

Leishmaniasis is caused by Leishmania parasites that infect several cell types. The promastigote stage of Leishmania is internalized by phagocytic cells and transformed into the obligate intracellular amastigote form. B-1 cells are a subpopulation of B cells that are able to differentiate in vitro and in vivo into mononuclear phagocyte-like cells with phagocytic properties. B-1 cells use several receptors for phagocytosis, such as the mannose receptor and third complement receptor. Leishmania binds to the same receptors on macrophages. In this study, we demonstrated that phagocytes derived from B-1 cells (B-1 CDP) were able to internalize promastigotes of L. (L.) amazonensis in vitro. The internalized promastigotes differentiated into amastigotes. Our results showed that the phagocytic index was higher in B-1 CDP compared to peritoneal macrophages and bone marrow-derived macrophages. The in vivo phagocytic ability of B-1 cells was also demonstrated. Parasites were detected inside purified B-1 cells after intraperitoneal infection with L. (L.) amazonensis promastigotes. Intraperitoneal stimulation with the parasites led to an increase in both IL-10 and TNF-α. These results highlight the importance of studying B-1 CDP cells as phagocytic cells that can participate and contribute to immunity to parasites. © 2016 John Wiley & Sons Ltd.

Comparison of fluorescence-based methods to determine nanoparticle uptake by phagocytes and non-phagocytic cells in vitro

PubMed Central

Claudia, Meindl; Kristin, Öhlinger; Jennifer, Ober; Eva, Roblegg; Eleonore, Fröhlich

2017-01-01

At many portals of entry the relative uptake by phagocytes and non-phagocytic cells has a prominent effect on availability and biological action of nanoparticles (NPs). Cellular uptake can be determined for fluorescence-labeled NPs. The present study compares three methods (plate reader, flow cytometry and image analysis) in order to investigate the influence of particle size and functionalization and medium content on cellular uptake of fluorescence–labeled polystyrene particles and to study the respective method’s suitability for uptake studies. For comparison between the techniques, ratios of macrophage to alveolar epithelial cell uptakes were used. Presence of serum protein in the exposure solution decreased uptake of carboxyl-functionalized and non-functionalized particles; there was no clear effect for the amine-functionalized particles. The 200 nm non- or carboxyl-functionalized NPs were taken up preferentially by phagocytes while for amine-functionalized particles preference was lowest. The presence of the serum slightly increased the preference for these particles. In conclusion, due to the possibility of calibration, plate reader measurements might present a better option than the other techniques to (semi)quantify differences between phagocytes and non-phagocytic cells for particles with different fluorescence. In order to obtain unbiased data the fluorescent labeling has to fulfill certain requirements. PMID:28065592

Continued clearance of apoptotic cells critically depends on the phagocyte Ucp2 protein.

PubMed

Park, Daeho; Han, Claudia Z; Elliott, Michael R; Kinchen, Jason M; Trampont, Paul C; Das, Soumita; Collins, Sheila; Lysiak, Jeffrey J; Hoehn, Kyle L; Ravichandran, Kodi S

2011-08-21

Rapid and efficient removal of apoptotic cells by phagocytes is important during development, tissue homeostasis and in immune responses. Efficient clearance depends on the capacity of a single phagocyte to ingest multiple apoptotic cells successively, and to process the corpse-derived cellular material. However, the factors that influence continued clearance by phagocytes are not known. Here we show that the mitochondrial membrane potential of the phagocyte critically controls engulfment capacity, with lower potential enhancing engulfment and vice versa. The mitochondrial membrane protein Ucp2, which acts to lower the mitochondrial membrane potential, was upregulated in phagocytes engulfing apoptotic cells. Loss of Ucp2 reduced phagocytic capacity, whereas Ucp2 overexpression enhanced engulfment. Mutational and pharmacological studies indicated a direct role for Ucp2-mediated mitochondrial function in phagocytosis. Macrophages from Ucp2-deficient mice were impaired in phagocytosis in vitro, and Ucp2-deficient mice showed profound in vivo defects in clearing dying cells in the thymus and testes. Collectively, these data indicate that mitochondrial membrane potential and Ucp2 are key molecular determinants of apoptotic cell clearance. As Ucp2 is linked to metabolic diseases and atherosclerosis, this newly discovered role for Ucp2 in apoptotic cell clearance has implications for the complex aetiology and pathogenesis of these diseases.

Nitric oxide and superoxide mediate diesel particle effects in cytokine-treated mice and murine lung epithelial cells — implications for susceptibility to traffic-related air pollution

PubMed Central

2012-01-01

Background Epidemiologic studies associate childhood exposure to traffic-related air pollution with increased respiratory infections and asthmatic and allergic symptoms. The strongest associations between traffic exposure and negative health impacts are observed in individuals with respiratory inflammation. We hypothesized that interactions between nitric oxide (NO), increased during lung inflammatory responses, and reactive oxygen species (ROS), increased as a consequence of traffic exposure ─ played a key role in the increased susceptibility of these at-risk populations to traffic emissions. Methods Diesel exhaust particles (DEP) were used as surrogates for traffic particles. Murine lung epithelial (LA-4) cells and BALB/c mice were treated with a cytokine mixture (cytomix: TNFα, IL-1β, and IFNγ) to induce a generic inflammatory state. Cells were exposed to saline or DEP (25 μg/cm2) and examined for differential effects on redox balance and cytotoxicity. Likewise, mice undergoing nose-only inhalation exposure to air or DEP (2 mg/m3 × 4 h/d × 2 d) were assessed for differential effects on lung inflammation, injury, antioxidant levels, and phagocyte ROS production. Results Cytomix treatment significantly increased LA-4 cell NO production though iNOS activation. Cytomix +  DEP-exposed cells incurred the greatest intracellular ROS production, with commensurate cytotoxicity, as these cells were unable to maintain redox balance. By contrast, saline + DEP-exposed cells were able to mount effective antioxidant responses. DEP effects were mediated by: (1) increased ROS including superoxide anion (O2˙-), related to increased xanthine dehydrogenase expression and reduced cytosolic superoxide dismutase activity; and (2) increased peroxynitrite generation related to interaction of O2˙- with cytokine-induced NO. Effects were partially reduced by superoxide dismutase (SOD) supplementation or by blocking iNOS induction. In mice, cytomix +  DEP-exposure resulted in greater ROS production in lung phagocytes. Phagocyte and epithelial effects were, by and large, prevented by treatment with FeTMPyP, which accelerates peroxynitrite catalysis. Conclusions During inflammation, due to interactions of NO and O2˙-, DEP-exposure was associated with nitrosative stress in surface epithelial cells and resident lung phagocytes. As these cell types work in concert to provide protection against inhaled pathogens and allergens, dysfunction would predispose to development of respiratory infection and allergy. Results provide a mechanism by which individuals with pre-existing respiratory inflammation are at increased risk for exposure to traffic-dominated urban air pollution. PMID:23151036

Bactericidal Action of Fresh Rabbit Blood Against Brucella abortus

PubMed Central

Joos, Richard W.; Hall, Wendell H.

1968-01-01

A photometric method was used to measure the bactericidal kinetics for Brucella abortus of freshly drawn rabbit blood during the time before clotting. This antibrucellar activity varied between rabbits in different immunologic states. Nonimmunized rabbits had moderate bactericidal activity after a lag of about 2 min. The blood of some immunized rabbits gave an immediate and strong kill, but in certain other immunized rabbits, especially when hyperimmunized, the bactericidal activity was inhibited. It appeared that serum bactericidins and complement are sometimes as active in unclotted blood as they are in serum. However, this bactericidal activity can be either increased or neutralized by immunization. The prozone bactericidal inhibition phenomenon (Neisser-Wechsberg) found in immune serum may, in fact, reflect inhibition taking place in vivo. Inhibition of the bactericidal activity in blood can contribute to the persistence of chronic infections and individual variations in resistance. PMID:4971893

One-year follow-up of the phagocytic activity of leukocytes after exposure of rats to asbestos and basalt fibers.

PubMed Central

Hurbánková, M

1994-01-01

The phagocytic activity of leukocytes in peripheral blood was investigated after 2, 24, and 48 hr; 1, 2, 4, and 8 weeks; and 6 and 12 months following intraperitoneal administration of asbestos and basalt fibers to Wistar rats. Asbestos and basalt fibers differed in their effects on the parameters studied. Both granulocyte count and phagocytic activity of leukocytes during the 1-year dynamic follow-up in both dust-exposed groups of animals changed in two phases, characterized by the initial stimulation of the acute phase I, followed by the suppression of the parameters in the chronic phase II. Exposure to asbestos and basalt fibers led, in phase II, to impairment of the phagocytic activity of granulocytes. Asbestos fibers also significantly decreased phagocytic activity of monocytes. Exposure to basalt fibers did not affect the phagocytic activity of monocytes in phase II. Results suggest that the monocytic component of leukocytes plays an important role in the development of diseases caused by exposure to fibrous dusts, but basalt fibers have lesser biological effects than asbestos fibers. PMID:7882931

MiR-155 enhances phagocytic activity of β-thalassemia/HbE monocytes via targeting of BACH1.

PubMed

Srinoun, Kanitta; Nopparatana, Chamnong; Wongchanchailert, Malai; Fucharoen, Suthat

2017-11-01

Abnormal red blood cell (RBC) clearance in β-thalassemia is triggered by activated monocytes. Recent reports indicate that miRNA (miR-) plays a role in monocyte activation. To study phagocytic function, we co-cultured monocytes of normal, non-splenectomized and splenectomized β-thalassemia/HbE individuals with RBCs obtained from normal, non-splenectomized and splenectomized β-thalassemia/HbE individuals. The phagocytic activity of β-thalassemia/HbE monocytes co-cultured with β-thalassemia/HbE RBCs was significantly higher than that of normal monocytes co-cultured with normal RBCs. Upregulation of monocyte miR-155 was observed in β-thalassemia/HbE patients. Increased miR-155 was associated with reductions in BTB and CNC Homology1 (BACH1) target gene expression and increased phagocytic activity of β-thalassemia/HbE monocytes. Taken together, these findings suggested that increased miR-155 expression in activated monocytes leads to enhanced phagocytic activity via BACH-1 regulation in β-thalassemia/HbE. This provides novel insights into the phagocytic clearance of abnormal RBCs in β-thalassemia/HbE.

Chloride flux in phagocytes.

PubMed

Wang, Guoshun

2016-09-01

Phagocytes, such as neutrophils and macrophages, engulf microbes into phagosomes and launch chemical attacks to kill and degrade them. Such a critical innate immune function necessitates ion participation. Chloride, the most abundant anion in the human body, is an indispensable constituent of the myeloperoxidase (MPO)-H2 O2 -halide system that produces the potent microbicide hypochlorous acid (HOCl). It also serves as a balancing ion to set membrane potentials, optimize cytosolic and phagosomal pH, and regulate phagosomal enzymatic activities. Deficient supply of this anion to or defective attainment of this anion by phagocytes is linked to innate immune defects. However, how phagocytes acquire chloride from their residing environment especially when they are deployed to epithelium-lined lumens, and how chloride is intracellularly transported to phagosomes remain largely unknown. This review article will provide an overview of chloride protein carriers, potential mechanisms for phagocytic chloride preservation and acquisition, intracellular chloride supply to phagosomes for oxidant production, and methods to measure chloride levels in phagocytes and their phagosomes. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Aggregation of Sea Urchin Phagocytes Is Augmented In Vitro by Lipopolysaccharide

PubMed Central

Majeske, Audrey J.; Bayne, Christopher J.; Smith, L. Courtney

2013-01-01

Development of protocols and media for culturing immune cells from marine invertebrates has not kept pace with advancements in mammalian immune cell culture, the latter having been driven by the need to understand the causes of and develop therapies for human and animal diseases. However, expansion of the aquaculture industry and the diseases that threaten these systems creates the need to develop cell and tissue culture methods for marine invertebrates. Such methods will enable us to better understand the causes of disease outbreaks and to develop means to avoid and remedy epidemics. We report a method for the short-term culture of phagocytes from the purple sea urchin, Strongylocentrotus purpuratus, by modifying an approach previously used to culture cells from another sea urchin species. The viability of cultured phagocytes from the purple sea urchin decreases from 91.6% to 57% over six days and phagocyte morphology changes from single cells to aggregates leading to the formation of syncytia-like structures. This process is accelerated in the presence of lipopolysaccharide suggesting that phagocytes are capable of detecting this molecular pattern in culture conditions. Sea urchin immune response proteins, called Sp185/333, are expressed on the surface of a subset of phagocytes and have been associated with syncytia-like structures. We evaluated their expression in cultured phagocytes to determine their possible role in cell aggregation and in the formation of syncytia-like structures. Between 0 and 3 hr, syncytia-like structures were observed in cultures when only ∼10% of the cells were positive for Sp185/333 proteins. At 24 hr, ∼90% of the nuclei were Sp185/333-positive when all of the phagocytes had aggregated into syncytia-like structures. Consequently, we conclude that the Sp185/333 proteins do not have a major role in initiating the aggregation of cultured phagocytes, however the Sp185/333 proteins are associated with the clustered nuclei within the syncytia-like structures. PMID:23613847

Aggregation of sea urchin phagocytes is augmented in vitro by lipopolysaccharide.

PubMed

Majeske, Audrey J; Bayne, Christopher J; Smith, L Courtney

2013-01-01

Development of protocols and media for culturing immune cells from marine invertebrates has not kept pace with advancements in mammalian immune cell culture, the latter having been driven by the need to understand the causes of and develop therapies for human and animal diseases. However, expansion of the aquaculture industry and the diseases that threaten these systems creates the need to develop cell and tissue culture methods for marine invertebrates. Such methods will enable us to better understand the causes of disease outbreaks and to develop means to avoid and remedy epidemics. We report a method for the short-term culture of phagocytes from the purple sea urchin, Strongylocentrotus purpuratus, by modifying an approach previously used to culture cells from another sea urchin species. The viability of cultured phagocytes from the purple sea urchin decreases from 91.6% to 57% over six days and phagocyte morphology changes from single cells to aggregates leading to the formation of syncytia-like structures. This process is accelerated in the presence of lipopolysaccharide suggesting that phagocytes are capable of detecting this molecular pattern in culture conditions. Sea urchin immune response proteins, called Sp185/333, are expressed on the surface of a subset of phagocytes and have been associated with syncytia-like structures. We evaluated their expression in cultured phagocytes to determine their possible role in cell aggregation and in the formation of syncytia-like structures. Between 0 and 3 hr, syncytia-like structures were observed in cultures when only ~10% of the cells were positive for Sp185/333 proteins. At 24 hr, ~90% of the nuclei were Sp185/333-positive when all of the phagocytes had aggregated into syncytia-like structures. Consequently, we conclude that the Sp185/333 proteins do not have a major role in initiating the aggregation of cultured phagocytes, however the Sp185/333 proteins are associated with the clustered nuclei within the syncytia-like structures.

Simultaneous flow cytometric measurement of antigen attachment to phagocytes and phagocytosis.

PubMed

Laopajon, Witida; Takheaw, Nuchjira; Kasinrerk, Watchara; Pata, Supansa

2016-01-01

The current available assays cannot differentiate the stages of phagocytosis. We, therefore, established methods for concurrent detection of antigen attachment and engulfment by phagocyte using latex beads coated with lipopolysaccharide, rabbit IgG, and carboxyfluorescein diacetate succinimidyl ester. The generated beads were incubated with whole blood at 37°C for 1 hr and stained with PE-Cy5.5 anti-rabbit IgG antibody. By flow cytometry, attachment and phagocytic processes could be detected, simultaneously. The established method is a valuable tool for diagnosis of phagocytic disorder and study of molecules involved in phagocytosis.

Is spaceflight-induced immune dysfunction linked to systemic changes in metabolism?

PubMed Central

Mao, Xiao Wen; Bellinger, Denise L.; Jonscher, Karen R.; Stodieck, Louis S.; Ferguson, Virginia L.; Bateman, Ted A.; Mohney, Robert P.; Gridley, Daila S.

2017-01-01

The Space Shuttle Atlantis launched on its final mission (STS-135) on July 8, 2011. After just under 13 days, the shuttle landed safely at Kennedy Space Center (KSC) for the last time. Female C57BL/6J mice flew as part of the Commercial Biomedical Testing Module-3 (CBTM-3) payload. Ground controls were maintained at the KSC facility. Subsets of these mice were made available to investigators as part of NASA’s Bio-specimen Sharing Program (BSP). Our group characterized cell phenotype distributions and phagocytic function in the spleen, catecholamine and corticosterone levels in the adrenal glands, and transcriptomics/metabolomics in the liver. Despite decreases in most splenic leukocyte subsets, there were increases in reactive oxygen species (ROS)-related activity. Although there were increases noted in corticosterone levels in both the adrenals and liver, there were no significant changes in catecholamine levels. Furthermore, functional analysis of gene expression and metabolomic profiles suggest that the functional changes are not due to oxidative or psychological stress. Despite changes in gene expression patterns indicative of increases in phagocytic activity (e.g. endocytosis and formation of peroxisomes), there was no corresponding increase in genes related to ROS metabolism. In contrast, there were increases in expression profiles related to fatty acid oxidation with decreases in glycolysis-related profiles. Given the clear link between immune function and metabolism in many ground-based diseases, we propose a similar link may be involved in spaceflight-induced decrements in immune and metabolic function. PMID:28542224

Inhibition of caspase activity prevents CD95-mediated hepatic microvascular perfusion failure and restores Kupffer cell clearance capacity.

PubMed

Wanner, G A; Mica, L; Wanner-Schmid, E; Kolb, S A; Hentze, H; Trentz, O; Ertel, W

1999-07-01

Using a murine model, we studied the effect of agonistic anti-CD95 antibodies (aCD95) on sinusoidal lining cells and a potential protection by caspase inhibition. C3H/HeN mice were intravenously administered aCD95 (10 microgram/mouse) or unspecific IgG (control) in the presence or absence of the caspase inhibitor z-VAD-fmk. Analysis of hepatic microcirculation using intravital fluorescence microscopy revealed severe (P<0.01) sinusoidal perfusion failure and reduced (P<0.05) phagocytic activity of Kupffer cells (KC) within 2 h. Transmission electron micrographs demonstrated loss of integrity of sinusoidal endothelial cells as early as 1 h after aCD95 application, whereas histological manifestation of hepatocellular apoptosis and hemorrhagic necrosis was most pronounced at 6 h. Blocking of caspase activity attenuated (P<0.01) both hepatic microvascular perfusion failure and KC dysfunction. Accordingly, full protection of the liver from apoptotic damage and intact microarchitecture was observed in histological sections after z-VAD-fmk treatment. Mortality rate was 40% 6 h after aCD95 administration, whereas all animals survived in the z-VAD-fmk group (P<0.05). The activation of caspases through CD95 may primarily lead to damage of sinusoidal endothelial cells and hepatic microvascular perfusion failure. Moreover, reduced phagocytic capacity of KC may contribute to accumulation of toxic metabolites released by dying cells at the local site of inflammation, further aggravating liver injury.

Alteration of Multiple Leukocyte Gene Expression Networks is Linked with Magnetic Resonance Markers of Prognosis After Acute ST-Elevation Myocardial Infarction.

PubMed

Teren, A; Kirsten, H; Beutner, F; Scholz, M; Holdt, L M; Teupser, D; Gutberlet, M; Thiery, J; Schuler, G; Eitel, I

2017-02-03

Prognostic relevant pathways of leukocyte involvement in human myocardial ischemic-reperfusion injury are largely unknown. We enrolled 136 patients with ST-elevation myocardial infarction (STEMI) after primary angioplasty within 12 h after onset of symptoms. Following reperfusion, whole blood was collected within a median time interval of 20 h (interquartile range: 15-25 h) for genome-wide gene expression analysis. Subsequent CMR scans were performed using a standard protocol to determine infarct size (IS), area at risk (AAR), myocardial salvage index (MSI) and the extent of late microvascular obstruction (lateMO). We found 398 genes associated with lateMO and two genes with IS. Neither AAR, nor MSI showed significant correlations with gene expression. Genes correlating with lateMO were strongly related to several canonical pathways, including positive regulation of T-cell activation (p = 3.44 × 10 -5 ), and regulation of inflammatory response (p = 1.86 × 10 -3 ). Network analysis of multiple gene expression alterations associated with larger lateMO identified the following functional consequences: facilitated utilisation and decreased concentration of free fatty acid, repressed cell differentiation, enhanced phagocyte movement, increased cell death, vascular disease and compensatory vasculogenesis. In conclusion, the extent of lateMO after acute, reperfused STEMI correlated with altered activation of multiple genes related to fatty acid utilisation, lymphocyte differentiation, phagocyte mobilisation, cell survival, and vascular dysfunction.

Is spaceflight-induced immune dysfunction linked to systemic changes in metabolism?

PubMed

Pecaut, Michael J; Mao, Xiao Wen; Bellinger, Denise L; Jonscher, Karen R; Stodieck, Louis S; Ferguson, Virginia L; Bateman, Ted A; Mohney, Robert P; Gridley, Daila S

2017-01-01

The Space Shuttle Atlantis launched on its final mission (STS-135) on July 8, 2011. After just under 13 days, the shuttle landed safely at Kennedy Space Center (KSC) for the last time. Female C57BL/6J mice flew as part of the Commercial Biomedical Testing Module-3 (CBTM-3) payload. Ground controls were maintained at the KSC facility. Subsets of these mice were made available to investigators as part of NASA's Bio-specimen Sharing Program (BSP). Our group characterized cell phenotype distributions and phagocytic function in the spleen, catecholamine and corticosterone levels in the adrenal glands, and transcriptomics/metabolomics in the liver. Despite decreases in most splenic leukocyte subsets, there were increases in reactive oxygen species (ROS)-related activity. Although there were increases noted in corticosterone levels in both the adrenals and liver, there were no significant changes in catecholamine levels. Furthermore, functional analysis of gene expression and metabolomic profiles suggest that the functional changes are not due to oxidative or psychological stress. Despite changes in gene expression patterns indicative of increases in phagocytic activity (e.g. endocytosis and formation of peroxisomes), there was no corresponding increase in genes related to ROS metabolism. In contrast, there were increases in expression profiles related to fatty acid oxidation with decreases in glycolysis-related profiles. Given the clear link between immune function and metabolism in many ground-based diseases, we propose a similar link may be involved in spaceflight-induced decrements in immune and metabolic function.

Comparison of fluorescence-based methods to determine nanoparticle uptake by phagocytes and non-phagocytic cells in vitro.

PubMed

Claudia, Meindl; Kristin, Öhlinger; Jennifer, Ober; Eva, Roblegg; Eleonore, Fröhlich

2017-03-01

At many portals of entry the relative uptake by phagocytes and non-phagocytic cells has a prominent effect on availability and biological action of nanoparticles (NPs). Cellular uptake can be determined for fluorescence-labeled NPs. The present study compares three methods (plate reader, flow cytometry and image analysis) in order to investigate the influence of particle size and functionalization and medium content on cellular uptake of fluorescence-labeled polystyrene particles and to study the respective method́s suitability for uptake studies. For comparison between the techniques, ratios of macrophage to alveolar epithelial cell uptakes were used. Presence of serum protein in the exposure solution decreased uptake of carboxyl-functionalized and non-functionalized particles; there was no clear effect for the amine-functionalized particles. The 200nm non- or carboxyl-functionalized NPs were taken up preferentially by phagocytes while for amine-functionalized particles preference was lowest. The presence of the serum slightly increased the preference for these particles. In conclusion, due to the possibility of calibration, plate reader measurements might present a better option than the other techniques to (semi)quantify differences between phagocytes and non-phagocytic cells for particles with different fluorescence. In order to obtain unbiased data the fluorescent labeling has to fulfill certain requirements. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

M-CSF Mediates Host Defense during Bacterial Pneumonia by Promoting the Survival of Lung and Liver Mononuclear Phagocytes.

PubMed

Bettina, Alexandra; Zhang, Zhimin; Michels, Kathryn; Cagnina, R Elaine; Vincent, Isaah S; Burdick, Marie D; Kadl, Alexandra; Mehrad, Borna

2016-06-15

Gram-negative bacterial pneumonia is a common and dangerous infection with diminishing treatment options due to increasing antibiotic resistance among causal pathogens. The mononuclear phagocyte system is a heterogeneous group of leukocytes composed of tissue-resident macrophages, dendritic cells, and monocyte-derived cells that are critical in defense against pneumonia, but mechanisms that regulate their maintenance and function during infection are poorly defined. M-CSF has myriad effects on mononuclear phagocytes but its role in pneumonia is unknown. We therefore tested the hypothesis that M-CSF is required for mononuclear phagocyte-mediated host defenses during bacterial pneumonia in a murine model of infection. Genetic deletion or immunoneutralization of M-CSF resulted in reduced survival, increased bacterial burden, and greater lung injury. M-CSF was necessary for the expansion of lung mononuclear phagocytes during infection but did not affect the number of bone marrow or blood monocytes, proliferation of precursors, or recruitment of leukocytes to the lungs. In contrast, M-CSF was essential to survival and antimicrobial functions of both lung and liver mononuclear phagocytes during pneumonia, and its absence resulted in bacterial dissemination to the liver and hepatic necrosis. We conclude that M-CSF is critical to host defenses against bacterial pneumonia by mediating survival and antimicrobial functions of mononuclear phagocytes in the lungs and liver. Copyright © 2016 by The American Association of Immunologists, Inc.

M-CSF mediates host defense during bacterial pneumonia by promoting the survival of lung and liver mononuclear phagocytes

PubMed Central

Bettina, Alexandra; Zhang, Zhimin; Michels, Kathryn; Cagnina, R. Elaine; Vincent, Isaah S.; Burdick, Marie D.; Kadl, Alexandra; Mehrad, Borna

2016-01-01

Gram-negative bacterial pneumonia is a common and dangerous infection with diminishing treatment options due to increasing antibiotic resistance among causal pathogens. The mononuclear phagocyte system is a heterogeneous group of leukocytes composed of tissue-resident macrophages, dendritic cells and monocyte-derived cells that are critical in defense against pneumonia, but mechanisms that regulate their maintenance and function during infection are poorly defined. Macrophage-colony stimulating factor (M-CSF) has myriad effects on mononuclear phagocytes but its role in pneumonia is unknown. We therefore tested the hypothesis that M-CSF is required for mononuclear phagocyte-mediated host defenses during bacterial pneumonia in a murine model of infection. Genetic deletion or immunoneutralization of M-CSF resulted in reduced survival, increased bacterial burden and greater lung injury. M-CSF was necessary for the expansion of lung mononuclear phagocytes during infection but did not affect the number of bone marrow or blood monocytes, the proliferation of precursors or the recruitment of leukocytes to the lungs. In contrast, M-CSF was essential to survival and anti-microbial functions of both lung and liver mononuclear phagocytes during pneumonia and its absence resulted in bacterial dissemination to the liver and hepatic necrosis. We conclude that M-CSF is critical to host defenses against bacterial pneumonia by mediating survival and anti-microbial functions of mononuclear phagocytes in the lungs and liver. PMID:27183631

[Modulating Effect of Extracellular HSP70 on Generation of Reactive Oxigen Species in Populations of Phagocytes].

PubMed

Troyanova, N I; Shevchenko, M A; Boyko, A A; Mirzoyev, R R; Pertseva, M A; Kovalenko, E I; Sapozhnikov, A M

2015-01-01

Reactive oxygen species (ROS) produced by phagocytic cells of the innate immune system play an important role in the first line of defense protecting the host from pathogens. The NADPH oxidase multi-subunit complex is the main source of ROS in all types of the phagocytes. Formation of the membrane-associated enzyme complex and its activity are dependent on many different factors controlling both intensification and suppression of the ROS production rate. However, the evidences are emerging in recent years indicating existence of poorly studied mechanisms of restriction of ROS generation level in phagocytes directed at protection of host tissues in the sites of inflammation from destruction caused by the oxygen free radicals. Our previous data and results of other authors demonstrate that a mechanism of the limitation of ROS production by phagocytes may by connected with immunomodulating activity of extracellular pool. of HSP70. In the present work, we used inhibitors of NADPH oxidase and in vitro cultures of different phagocytes to study a possible relationship between down-regulating effect of exogenous HSP70 on ROS generation and the interaction of the protein with the enzyme subunits. Our results confirmed the literature data concerning the ability of extracellular HSP70 to modulate NADPH oxidase activity and demonstrated for the first time an inhibitory effect of the protein on intracellular ROS generation in phagocytes.

Illuminating Phagocyte Biology: The View from Zebrafish.

PubMed

Huang, Cong; Niethammer, Philipp

2016-07-25

Many phagocyte behaviors, including vascular rolling and adhesion, migration, and oxidative bursting, are better measured in seconds or minutes than hours or days. Zebrafish is ideally suited for imaging such rapid biology within the intact animal. We discuss how this model has revealed unique insights into various aspects of phagocyte physiology. Copyright © 2016 Elsevier Inc. All rights reserved.

Polymeric stent materials dysregulate macrophage and endothelial cell functions: implications for coronary artery stent

PubMed Central

Wang, Xintong; Zachman, Angela L.; Chun, Young Wook; Shen, Fang-Wen; Hwang, Yu-Shik; Sung, Hak-Joon

2014-01-01

Background Biodegradable polymers have been applied as bulk or coating materials for coronary artery stents. The degradation of polymers, however, could induce endothelial dysfunction and aggravate neointimal formation. Here we use polymeric microparticles to simulate and demonstrate the effects of degraded stent materials on phagocytic activity, cell death and dysfunction of macrophages and endothelial cells. Methods Microparticles made of low molecular weight polyesters were incubated with human macrophages and coronary artery endothelial cells (ECs). Microparticle-induced phagocytosis, cytotoxicity, apoptosis, cytokine release and surface marker expression were determined by immunostaining or ELISA. Elastase expression was analyzed by ELISA and the elastase-mediated polymer degradation was assessed by mass spectrometry. Results We demonstrated poly(D,L-lactic acid) (PLLA) and polycaprolactone (PCL) microparticles induced cytotoxicity in macrophages and ECs, partially through cell apoptosis. The particle treatment alleviated EC phagocytosis, as opposed to macrophages, but enhanced the expression of vascular cell adhesion molecule-1 (VCAM) along with decreased nitric oxide production, indicating ECs were activated and lost their capacity to maintain homeostasis. The activation of both cell types induced release of elastase or elastase-like protease, which further accelerated polymer degradation. Conclusions This study revealed that low molecule weight PLLA and PCL microparticles increased cytotoxicity and dysregulated endothelial cell function, which in turn enhanced elastase release and polymer degradation. These indicate polymer or polymer-coated stents impose a risk of endothelial dysfunction after deployment which can potentially lead to delayed endothelialization, neointimal hyperplasia and late thrombosis. PMID:24820736

Evolutionary Conservation of Divergent Pro-Inflammatory and Homeostatic Responses in Lamprey Phagocytes

PubMed Central

Havixbeck, Jeffrey J.; Rieger, Aja M.; Wong, Michael E.; Wilkie, Michael P.; Barreda, Daniel R.

2014-01-01

In higher vertebrates, phagocytosis plays a critical role in development and immunity, based on the internalization and removal of apoptotic cells and invading pathogens, respectively. Previous studies describe the effective uptake of these particles by lower vertebrate and invertebrate phagocytes, and identify important molecular players that contribute to this internalization. However, it remains unclear if individual phagocytes mediate internalization processes in these ancient organisms, and how this impacts the balance of pro-inflammatory and homeostatic events within their infection sites. Herein we show that individual phagocytes of the jawless vertebrate Petromyzon marinus (sea lamprey), like those of teleost fish and mice, display the capacity for divergent pro-inflammatory and homeostatic responses following internalization of zymosan and apoptotic cells, respectively. Professional phagocytes (macrophages, monocytes, neutrophils) were the primary contributors to the internalization of pro-inflammatory particles among goldfish (C. auratus) and lamprey (P. marinus) hematopoietic leukocytes. However, goldfish showed a greater ability for zymosan phagocytosis when compared to their jawless counterparts. Coupled to this increase was a significantly lower sensitivity of goldfish phagocytes to homeostatic signals derived from apoptotic cell internalization. Together, this translated into a significantly greater capacity for induction of antimicrobial respiratory burst responses compared to lamprey phagocytes, but also a decreased efficacy in apoptotic cell-driven leukocyte homeostatic mechanisms that attenuate this pro-inflammatory process. Overall, our results show the long-standing evolutionary contribution of intrinsic phagocyte mechanisms for the control of inflammation, and illustrate one effective evolutionary strategy for increased responsiveness against invading pathogens. In addition, they highlight the need for development of complementary regulatory mechanisms of inflammation to ensure continued maintenance of host integrity amidst increasing challenges from invading pathogens. PMID:24465992

Evolutionary conservation of divergent pro-inflammatory and homeostatic responses in Lamprey phagocytes.

PubMed

Havixbeck, Jeffrey J; Rieger, Aja M; Wong, Michael E; Wilkie, Michael P; Barreda, Daniel R

2014-01-01

In higher vertebrates, phagocytosis plays a critical role in development and immunity, based on the internalization and removal of apoptotic cells and invading pathogens, respectively. Previous studies describe the effective uptake of these particles by lower vertebrate and invertebrate phagocytes, and identify important molecular players that contribute to this internalization. However, it remains unclear if individual phagocytes mediate internalization processes in these ancient organisms, and how this impacts the balance of pro-inflammatory and homeostatic events within their infection sites. Herein we show that individual phagocytes of the jawless vertebrate Petromyzon marinus (sea lamprey), like those of teleost fish and mice, display the capacity for divergent pro-inflammatory and homeostatic responses following internalization of zymosan and apoptotic cells, respectively. Professional phagocytes (macrophages, monocytes, neutrophils) were the primary contributors to the internalization of pro-inflammatory particles among goldfish (C. auratus) and lamprey (P. marinus) hematopoietic leukocytes. However, goldfish showed a greater ability for zymosan phagocytosis when compared to their jawless counterparts. Coupled to this increase was a significantly lower sensitivity of goldfish phagocytes to homeostatic signals derived from apoptotic cell internalization. Together, this translated into a significantly greater capacity for induction of antimicrobial respiratory burst responses compared to lamprey phagocytes, but also a decreased efficacy in apoptotic cell-driven leukocyte homeostatic mechanisms that attenuate this pro-inflammatory process. Overall, our results show the long-standing evolutionary contribution of intrinsic phagocyte mechanisms for the control of inflammation, and illustrate one effective evolutionary strategy for increased responsiveness against invading pathogens. In addition, they highlight the need for development of complementary regulatory mechanisms of inflammation to ensure continued maintenance of host integrity amidst increasing challenges from invading pathogens.

Alarmins MRP8 and MRP14 induce stress tolerance in phagocytes under sterile inflammatory conditions.

PubMed

Austermann, Judith; Friesenhagen, Judith; Fassl, Selina Kathleen; Petersen, Beatrix; Ortkras, Theresa; Burgmann, Johanna; Barczyk-Kahlert, Katarzyna; Faist, Eugen; Zedler, Siegfried; Pirr, Sabine; Rohde, Christian; Müller-Tidow, Carsten; von Köckritz-Blickwede, Maren; von Kaisenberg, Constantin S; Flohé, Stefanie B; Ulas, Thomas; Schultze, Joachim L; Roth, Johannes; Vogl, Thomas; Viemann, Dorothee

2014-12-24

Hyporesponsiveness by phagocytes is a well-known phenomenon in sepsis that is frequently induced by low-dose endotoxin stimulation of Toll-like receptor 4 (TLR4) but can also be found under sterile inflammatory conditions. We now demonstrate that the endogenous alarmins MRP8 and MRP14 induce phagocyte hyporesponsiveness via chromatin modifications in a TLR4-dependent manner that results in enhanced survival to septic shock in mice. During sterile inflammation, polytrauma and burn trauma patients initially present with high serum concentrations of myeloid-related proteins (MRPs). Human neonatal phagocytes are primed for hyporesponsiveness by increased peripartal MRP concentrations, which was confirmed in murine neonatal endotoxinemia in wild-type and MRP14(-/-) mice. Our data therefore indicate that alarmin-triggered phagocyte tolerance represents a regulatory mechanism for the susceptibility of neonates during systemic infections and sterile inflammation. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Beta cells transfer vesicles containing insulin to phagocytes for presentation to T cells.

PubMed

Vomund, Anthony N; Zinselmeyer, Bernd H; Hughes, Jing; Calderon, Boris; Valderrama, Carolina; Ferris, Stephen T; Wan, Xiaoxiao; Kanekura, Kohsuke; Carrero, Javier A; Urano, Fumihiko; Unanue, Emil R

2015-10-06

Beta cells from nondiabetic mice transfer secretory vesicles to phagocytic cells. The passage was shown in culture studies where the transfer was probed with CD4 T cells reactive to insulin peptides. Two sets of vesicles were transferred, one containing insulin and another containing catabolites of insulin. The passage required live beta cells in a close cell contact interaction with the phagocytes. It was increased by high glucose concentration and required mobilization of intracellular Ca2+. Live images of beta cell-phagocyte interactions documented the intimacy of the membrane contact and the passage of the granules. The passage was found in beta cells isolated from islets of young nonobese diabetic (NOD) mice and nondiabetic mice as well as from nondiabetic humans. Ultrastructural analysis showed intraislet phagocytes containing vesicles having the distinct morphology of dense-core granules. These findings document a process whereby the contents of secretory granules become available to the immune system.

[Bactericidal activity of serum and chemotherapy in sensitive and resistant exciter (author's transl)].

PubMed

Eyer, H; Metz, H; Preac-Mursic, V

1975-11-21

Comparing examinations with Ampicillin sensitive and resistant bacteria-strains show that the bactericidal activity of serum is dependent on the bacteria-strains, on the Ampicillin sensitivity of the particular exciter and on the number of bacteria/ml (germ count). Bactericide effect could always be obtained with sensitive strains as a result of additional chemotherapy. With several resistant strains a bactericide effect could not be obtained in this case the continuous optimal Ampicillin addition was the decisive factor. Because of the extremely complicated process of the bactericide one should not make general conclusions from the individual experimental results.

Macrophage Efferocytosis and Prostate Cancer Bone Metastasis

DTIC Science & Technology

2015-10-01

prostate cancer bone metastasis through the phagocytosis of apoptotic tumor cells (efferocytosis). Specific Aims: 1. To identify the phagocytic ...2: To identify the phagocytic /efferocytic macrophage population in the tumor microenvironment of prostate bone metastases and determine its ability...preparation for Cancer Research. We obtained an array of prostate cancer tissue including bone metastasis (N=72) and stained the tissue for the phagocytic

Effect of cefodizime and ceftriaxone on phagocytic function in patients with severe infections.

PubMed Central

Wenisch, C; Parschalk, B; Hasenhündl, M; Wiesinger, E; Graninger, W

1995-01-01

Thirty patients with severe bacterial infections were treated with 50 mg of cefodizime per kg of body weight once daily or 50 mg of ceftriaxone per kg once daily for 10 +/- 3 days. The effect of cefodizime and ceftriaxone on the phagocytic capacity and generation of reactive oxygen intermediates after phagocytosis by granulocytes was assessed prior to, during, and after therapy. Flow cytometry was used to study phagocytic capacity by measuring the uptake of fluorescein-labeled bacteria. The generation of reactive oxygen intermediates after phagocytosis was estimated by the quantification of the intracellular conversion of dihydrorhodamine 123 to rhodamine 123. Prior to therapy, patients in both groups exhibited a decreased capacity to phagocytize Escherichia coli and subsequently to generate reactive oxygen intermediates. Granulocyte function increased after the initiation of therapy and normalized within 7 days for the ceftriaxone-treated patients and within 3 days for the cefodizime group (P < 0.05). In the cefodizime group, an enhancement of phagocytic capacity was observed 14 days after the initiation of therapy (P < 0.05). Prior to therapy, phagocytic capacity was significantly correlated with the generation of reactive oxygen products (r = 0.674 and P < 0.005). PMID:7793871

SIRPα controls the activity of the phagocyte NADPH oxidase by restricting the expression of gp91(phox).

PubMed

van Beek, Ellen M; Zarate, Julian Alvarez; van Bruggen, Robin; Schornagel, Karin; Tool, Anton T J; Matozaki, Takashi; Kraal, Georg; Roos, Dirk; van den Berg, Timo K

2012-10-25

The phagocyte NADPH oxidase mediates oxidative microbial killing in granulocytes and macrophages. However, because the reactive oxygen species produced by the NADPH oxidase can also be toxic to the host, it is essential to control its activity. Little is known about the endogenous mechanism(s) that limits NADPH oxidase activity. Here, we demonstrate that the myeloid-inhibitory receptor SIRPα acts as a negative regulator of the phagocyte NADPH oxidase. Phagocytes isolated from SIRPα mutant mice were shown to have an enhanced respiratory burst. Furthermore, overexpression of SIRPα in human myeloid cells prevented respiratory burst activation. The inhibitory effect required interactions between SIRPα and its natural ligand, CD47, as well as signaling through the SIRPα cytoplasmic immunoreceptor tyrosine-based inhibitory motifs. Suppression of the respiratory burst by SIRPα was caused by a selective repression of gp91(phox) expression, the catalytic component of the phagocyte NADPH oxidase complex. Thus, SIRPα can limit gp91(phox) expression during myeloid development, thereby controlling the magnitude of the respiratory burst in phagocytes. Copyright © 2012 The Authors. Published by Elsevier Inc. All rights reserved.

Regulation of mononuclear phagocyte development by IRF8.

PubMed

Tamura, Tomohiko

2017-01-01

Mononuclear phagocytes, such as monocytes and dendritic cells (DCs), are essential for tissue homeostasis and immunity. In adults, these cells develop from hematopoietic stem cells via a common progenitor population. We have been investigating the mechanism underlying the development of mononuclear phagocytes from the viewpoint of gene expression control by transcription factors. Particularly, IRF8, the loss of which causes immunodeficiency and chronic myeloid leukemia-like neutrophilia in mice and humans, promotes the development of monocytes and DCs, while it limits neutrophil differentiation. IRF8 cooperates with the myeloid master transcription factor, PU.1, in mononuclear phagocyte progenitors. KLF4 and BATF3 serve as critical transcription factors downstream of IRF8 to induce the differentiation of monocytes and DCs, respectively. Conversely, IRF8 blocks the activity of the transcription factor C/EBPα to suppress the neutrophil differentiation program. Indeed, Irf8 -/- mononuclear phagocyte progenitors do not efficiently generate monocytes and DCs and, instead, aberrantly give rise to a large number of neutrophils. Our recent data have begun to uncover the vital role of IRF8 in the establishment of distal enhancers in mononuclear phagocyte progenitors. These results place IRF8 as a central regulator of the development of monocytes and DCs.

Effects of freezing on the bactericidal activity of human milk.

PubMed

Takci, Sahin; Gulmez, Dolunay; Yigit, Sule; Dogan, Ozlem; Dik, Kezban; Hascelik, Gulsen

2012-08-01

Storage of human milk by freezing has been recommended for long-term storage. The present study analyzed the bactericidal activity of human milk on Escherichia coli and Pseudomonas aeruginosa and determined the changes in bactericidal activity following freezing at -20°C and -80°C for 1 month and 3 months. Forty-eight milk samples were collected from 48 lactating mothers. Each sample was divided into 10 aliquots. Two of the samples were processed immediately and the others were stored at both -20°C and -80°C until analysis after 1 month and 3 months of freezing. All of the fresh milk samples showed bactericidal activity against E coli and P aeruginosa. Freezing at -20°C for 1 month did not cause statistically significant alteration in bactericidal activity (P > 0.017), whereas storage for 3 months lowered the degree of bactericidal activity significantly (P < 0.017) against E coli. Bactericidal activity was protected when the samples were stored at -80°C. There was no statistically significant difference in the bactericidal activity of human milk against E coli between freezing at -20°C and -80°C for 1 month (P > 0.017); however, when milk was stored for 3 months, -80°C was significantly more protective (P < 0.017). Freezing at -20°C and -80°C for 1 month and 3 months did not cause any significant change in bactericidal activity against P aeruginosa (P > 0.05). Storage by freezing at -80°C is more appropriate to keep bactericidal capacity of stored human milk >1 month if affordable and available, especially in intensive care settings.

The air-bubble method of locking central-vein catheters with acidified, concentrated sodium chloride as a bactericidal agent: in vitro studies.

PubMed

Moore, Harold L; Twardowski, Zbylut J

2003-10-01

Soft, cuffed indwelling catheters are used for hemodialysis access and intravenous infusions. The majority of these catheters are removed as a result of infection caused by contamination of the catheter hub during the connection/disconnection procedures. To prevent clot formation in the lumen, these catheters are routinely "locked" with heparin or some other anticoagulant. None of the anticoagulants commonly used as locking solutions demonstrates any significant bactericidal properties. The primary goal of this study was the development of a catheter locking method that retains anticoagulant properties at the catheter tip and bactericidal properties at the catheter hub. The second goal was to find a solution that possesses excellent bactericidal properties but is not detrimental in the event of injection into the patient's blood stream. The bactericidal properties of acidified, concentrated saline (ACS) were compared to concentrated trisodium citrate and to commonly used bactericidal agents such as povidone iodine, sodium hypochlorite, and chlorhexidine. In preliminary studies, the rate of diffusion of solutes was measured in glass tubes. In another set of experiments, the mixing of two solutions (anticoagulant and bactericide) separated by an air bubble ("air-bubble method") was observed in stationary and moving systems. The final series of studies compared the bactericidal properties of ACS to other bactericidal solutions mentioned above. The solutions diffused swiftly in the glass tubes, and by the third day, both solutions were mixed. The air-bubble method prevented mixing in both stationary and moving systems. The bactericidal properties of ACS were superior to all other tested solutions. The proposed method of catheter locking with anticoagulant at the catheter tip and ACS at the catheter hub separated by an air bubble is a promising technique and clinical studies are warranted.

Comparative studies of mononuclear phagocyte function in patients with Crohn's disease and colon neoplasms.

PubMed Central

Beeken, W L; St Andre-Ukena, S; Gundel, R M

1983-01-01

Phagocytosis and cellular cytotoxicity by mononuclear phagocytes of blood and intestinal mucosa were studied in patients with Crohn's disease and large bowel neoplasms. Antibody coated sheep erythrocytes were used for phagocytic assays and cellular cytotoxicity in vitro was measured by 24 hour isotope release from 75Selenium methionine-labelled RPMI 4788 human cancer cell cultures in the presence of mononuclear phagocyte-enriched effector populations. The mean percent of mononuclear phagocytes in Ficoll-Hypaque purified mononuclear cell suspensions of blood of healthy controls was 25.9 compared with 44.6 in patients with Crohn's disease, 45.6 in patients with colon neoplasms and 11.6 in intestinal mucosa. Phagocytic indices were similar in all groups, but the phagocytic capacity of mucosal macrophages was twice that of blood monocytes. Mean cytotoxicity of monocytes of patients with Crohn's disease was 12.8% compared with 22.9% for monocytes from normal controls, and 29.4% for patients with colon tumours. Mean cytotoxicity by mucosal macrophages was 18.0% compared with 13.2% by mucosal lymphocyte populations. Exposure of monocytes of Crohn's disease patients to bacterial lipopolysaccharide modestly increased cytotoxicity, but exposure did not alter phagocytosis by monocytes of patients or controls. The results indicate that monocytes of patients with Crohn's disease exhibit subnormal in vitro cytotoxicity. Mucosal macrophages from patients with various diseases show enhanced phagocytosis compared with blood monocytes, and they can mediate cellular cytotoxicity in vitro. PMID:6629113

Multi-parametric analysis of phagocyte antimicrobial responses using imaging flow cytometry.

PubMed

Havixbeck, Jeffrey J; Wong, Michael E; More Bayona, Juan A; Barreda, Daniel R

2015-08-01

We feature a multi-parametric approach based on an imaging flow cytometry platform for examining phagocyte antimicrobial responses against the gram-negative bacterium Aeromonas veronii. This pathogen is known to induce strong inflammatory responses across a broad range of animal species, including humans. We examined the contribution of A. veronii to the induction of early phagocyte inflammatory processes in RAW 264.7 murine macrophages in vitro. We found that A. veronii, both in live or heat-killed forms, induced similar levels of macrophage activation based on NF-κB translocation. Although these macrophages maintained high levels of viability following heat-killed or live challenges with A. veronii, we identified inhibition of macrophage proliferation as early as 1h post in vitro challenge. The characterization of phagocytic responses showed a time-dependent increase in phagocytosis upon A. veronii challenge, which was paired with a robust induction of intracellular respiratory burst responses. Interestingly, despite the overall increase in the production of reactive oxygen species (ROS) among RAW 264.7 macrophages, we found a significant reduction in the production of ROS among the macrophage subset that had bound A. veronii. Phagocytic uptake of the pathogen further decreased ROS production levels, even beyond those of unstimulated controls. Overall, this multi-parametric imaging flow cytometry-based approach allowed for segregation of unique phagocyte sub-populations and examination of their downstream antimicrobial responses, and should contribute to improved understanding of phagocyte responses against Aeromonas and other pathogens. Copyright © 2015 Elsevier B.V. All rights reserved.

Phagocyte dynamics in a highly regenerative urochordate: insights into development and host defense.

PubMed

Lauzon, Robert J; Brown, Christina; Kerr, Louie; Tiozzo, Stefano

2013-02-15

Phagocytosis is a cellular process by which particles and foreign bodies are engulfed and degraded by specialized cells. It is functionally involved in nutrient acquisition and represents a fundamental mechanism used to remove pathogens and cellular debris. In the marine invertebrate chordate Botryllus schlosseri, cell corpse engulfment by phagocytic cells is the recurrent mechanism of programmed cell clearance and a critical process for the successful execution of asexual regeneration and colony homeostasis. In the present study, we have utilized a naturally occurring process of vascular parabiosis coupled with intravascular microinjection of fluorescent bioparticles and liposomes as tools to investigate the dynamics of phagocyte behavior in real-time during cyclical body regeneration. Our findings indicate that B. schlosseri harbors two major populations of post-mitotic phagocytes, which display distinct phagocytic specificity and homing patterns: a static population that lines the circulatory system epithelia, and a mobile population that continuously recirculates throughout the colony and exhibits a characteristic homing pattern within mesenchymal niches called ventral islands (VI). We observed that a significant proportion of ventral island phagocytes (VIP) die and are engulfed by other VIP following takeover. Selective impairment of VIP activity curtailed zooid resorption and asexual development. Together, these findings strongly suggest that ventral islands are sites of phagocyte homing and turnover. As botryllid ascidians represent invertebrate chordates capable of whole body regeneration in a non-embryonic scenario, we discuss the pivotal role that phagocytosis plays in homeostasis, tissue renewal and host defense. Copyright © 2012 Elsevier Inc. All rights reserved.

Antibiotic efficacy is linked to bacterial cellular respiration

PubMed Central

Lobritz, Michael A.; Belenky, Peter; Porter, Caroline B. M.; Gutierrez, Arnaud; Yang, Jason H.; Schwarz, Eric G.; Dwyer, Daniel J.; Khalil, Ahmad S.; Collins, James J.

2015-01-01

Bacteriostatic and bactericidal antibiotic treatments result in two fundamentally different phenotypic outcomes—the inhibition of bacterial growth or, alternatively, cell death. Most antibiotics inhibit processes that are major consumers of cellular energy output, suggesting that antibiotic treatment may have important downstream consequences on bacterial metabolism. We hypothesized that the specific metabolic effects of bacteriostatic and bactericidal antibiotics contribute to their overall efficacy. We leveraged the opposing phenotypes of bacteriostatic and bactericidal drugs in combination to investigate their activity. Growth inhibition from bacteriostatic antibiotics was associated with suppressed cellular respiration whereas cell death from most bactericidal antibiotics was associated with accelerated respiration. In combination, suppression of cellular respiration by the bacteriostatic antibiotic was the dominant effect, blocking bactericidal killing. Global metabolic profiling of bacteriostatic antibiotic treatment revealed that accumulation of metabolites involved in specific drug target activity was linked to the buildup of energy metabolites that feed the electron transport chain. Inhibition of cellular respiration by knockout of the cytochrome oxidases was sufficient to attenuate bactericidal lethality whereas acceleration of basal respiration by genetically uncoupling ATP synthesis from electron transport resulted in potentiation of the killing effect of bactericidal antibiotics. This work identifies a link between antibiotic-induced cellular respiration and bactericidal lethality and demonstrates that bactericidal activity can be arrested by attenuated respiration and potentiated by accelerated respiration. Our data collectively show that antibiotics perturb the metabolic state of bacteria and that the metabolic state of bacteria impacts antibiotic efficacy. PMID:26100898

Bactericidal activity of wasabi (Wasabia japonica) against Helicobacter pylori.

PubMed

Shin, Il Shik; Masuda, Hideki; Naohide, Kinae

2004-08-01

In this study, the bactericidal activity of Korean and Japanese wasabi roots, stems and leaves against Helicobacter pylori were examined. Allyl isothiocyanate (AIT) in roots, stems and leaves of Korean wasabi were 0.75, 0.18 and 0.32 mg/g, respectively. AIT in roots, stems and leaves of Japanese wasabi were 1.18, 0.41 and 0.38 mg/g, respectively. All parts of wasabi showed bactericidal activities against H. pylori strain NCTC 11637, YS 27 and YS 50. The leaves of both wasabi showed the highest bactericidal activities with the minimum bactericidal concentration of 1.05-1.31 mg of dry weight/ml against three strains of H. pylori. The roots showed a little lower bactericidal activity with 2.09-4.17 mg of dry weight/ml against them. The main component related to antimicrobial activity in wasabi is well known to be AIT. In this study, the bactericidal activity of leaves was higher than that of roots, although AIT amount of leaves was lower than that of roots. These results suggest that certain components besides AIT in wasabi are effective in killing H. pylori.

Two Major Medicinal Honeys Have Different Mechanisms of Bactericidal Activity

PubMed Central

Kwakman, Paulus H. S.; te Velde, Anje A.; de Boer, Leonie; Vandenbroucke-Grauls, Christina M. J. E.; Zaat, Sebastian A. J.

2011-01-01

Honey is increasingly valued for its antibacterial activity, but knowledge regarding the mechanism of action is still incomplete. We assessed the bactericidal activity and mechanism of action of Revamil® source (RS) honey and manuka honey, the sources of two major medical-grade honeys. RS honey killed Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa within 2 hours, whereas manuka honey had such rapid activity only against B. subtilis. After 24 hours of incubation, both honeys killed all tested bacteria, including methicillin-resistant Staphylococcus aureus, but manuka honey retained activity up to higher dilutions than RS honey. Bee defensin-1 and H2O2 were the major factors involved in rapid bactericidal activity of RS honey. These factors were absent in manuka honey, but this honey contained 44-fold higher concentrations of methylglyoxal than RS honey. Methylglyoxal was a major bactericidal factor in manuka honey, but after neutralization of this compound manuka honey retained bactericidal activity due to several unknown factors. RS and manuka honey have highly distinct compositions of bactericidal factors, resulting in large differences in bactericidal activity. PMID:21394213

Unique phagocytic properties of hemocytes of Pacific oyster Crassostrea gigas against yeast and yeast cell-wall derivatives.

PubMed

Takahashi, Keisuke G; Izumi-Nakajima, Nakako; Mori, Katsuyoshi

2017-11-01

For a marine bivalve mollusk such as Pacific oyster Crassostrea gigas, the elimination of foreign particles via hemocyte phagocytosis plays an important role in host defense mechanisms. The hemocytes of C. gigas have a high phagocytic ability for baker's yeast (Saccharomyces cerevisiae) and its cell-wall product zymosan. C. gigas hemocytes might phagocytose yeast cells after binding to polysaccharides on the cell-wall surface, but it is unknown how and what kinds of polysaccharide molecules are recognized. We conducted experiments to determine differences in the phagocytic ability of C. gigas hemocytes against heat-killed yeast (HK yeast), zymosan and zymocel, which are similarly sized and shaped but differ in the polysaccharide composition of their particle surface. We found that both the agranulocytes and granulocytes exerted strong phagocytic ability on all tested particles. The phagocytic index (PI) of granulocytes for zymosan was 9.4 ± 1.7, which significantly differed with that for HK yeast and zymocel (P < 0.05). To evaluate the PI for the three types of particles, and especially to understand the outcome of the much higher PI for zymosan, PI was gauged in increments of 5 (1-5, 6-10, 11-15, and ≥16), and the phagocytic frequencies were compared according to these increments. The results show that a markedly high PI of ≥16 was exhibited by 18.1% of granulocytes for zymosan, significantly higher than 1.7% and 3.9% shown for HK yeast and zymocel, respectively (P < 0.05). These findings indicate that the relatively high PI for zymosan could not be attributed to a situation wherein all phagocytic hemocytes shared a high mean PI, but rather to the ability of some hemocytes to phagocytose a larger portion of zymosan. To determine whether the phagocytosis of these respective particles depended on the recognition of specific polysaccharide receptors on the hemocyte surface, C. gigas hemocytes were pretreated with soluble α-mannan or β-laminarin and then allowed to phagocytose the three types of the particles. The percentage of phagocytic cells of β-laminarin-treated granulocytes decreased significantly for zymosan and zymocel, but not for yeast. These results suggest that C. gigas might possess at least two types of hemocytes, and that one type of the hemocytes (granulocytes) is more active for phagocytosis. The granulocytes were found to have multiple subtypes with different phagocytic abilities and multiple phagocytic receptors. Some of the granulocyte subtypes revealed a much stronger phagocytic ability, depending on the presence of β-glucan receptors for phagocytosis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Physics of phagocytosis of foreign versus self-tolerance

NASA Astrophysics Data System (ADS)

Tsai, Richard; Rodriguez, Pia; Discher, Dennis

2009-03-01

The first cells to `attack' an implanted or injected foreign material or microbe are phagocytic cells of the innate immune system. These cells actively and rapidly phagocytose foreign cells, surfaces, or particles, but the process that is inefficient when faced with ``self'' cells. We have examined the biochemistry and some of the physics of this decision to eat or not eat. One particular protein on all animal cell membranes, called CD47, seems to engage phagocytic cell couter-receptors, and deactivate the force-generating myosin machinery that otherwise makes phagocytosis efficient. We will map the phagocytic synapse between phagocytes and particles or cells and describe the physicochemical dynamics that mediate this key decision in compatability.

Diffusion Barriers, Mechanical Forces, and the Biophysics of Phagocytosis.

PubMed

Ostrowski, Philip P; Grinstein, Sergio; Freeman, Spencer A

2016-07-25

Phagocytes recognize and eliminate pathogens, alert other tissues of impending threats, and provide a link between innate and adaptive immunity. They also maintain tissue homeostasis, consuming dead cells without causing alarm. The receptor engagement, signal transduction, and cytoskeletal rearrangements underlying phagocytosis are paradigmatic of other immune responses and bear similarities to macropinocytosis and cell migration. We discuss how the glycocalyx restricts access to phagocytic receptors, the processes that enable receptor engagement and clustering, and the remodeling of the actin cytoskeleton that controls the mobility of membrane proteins and lipids and provides the mechanical force propelling the phagocyte membrane toward and around the phagocytic prey. Copyright © 2016 Elsevier Inc. All rights reserved.

Reactivity of airway phagocytes during the development of acute pneumonia under conditions of stimulation of mononuclear phagocyte system with zymosan.

PubMed

Makarova, O P

2008-12-01

Pneumonia was induced in (CBA x C57Bl)F1 mice under conditions of stimulation of the mononuclear phagocyte system with zymosan. The number of neutrophils in airways increased after 3 days; by day 14, the number of cells in the bronchoalveolar lavage fluid further increased due to migration of macrophages. After zymosan prestimulation, the number and functional activity of neutrophils during the early period of inflammation (3 days) did not change, but the increase in phagocytic activity of macrophages was inhibited by 20%. By day 14, the effect of prestimulation manifested in 4.5-fold decreased capacity of neutrophils and macrophages to reduce NBT.

An unreported clindamycin adverse reaction: wrist monoarthritis.

PubMed

Alikhani, Ahmad; Salehifar, Ebrahim

2012-01-01

Clindamycin is a lincosamide antibiotic which is approved for the treatment of Anaerobic, Streptococcal and Staphylococcal infections. There has been an increased interest in the use of clindamycin since it achieves high intracellular levels in phagocytic cells, high levels in bone and appears to have an antitoxin effect against the toxin elaborating strains of streptococci and staphylococci. Clindamycin is considered as a bacteriostatic antibiotic, while it is bactericidal against some strains of Staphylococci, Streptococci and Anaerobes such as B. fragilis. Its major disadvantage is its propensity to cause antibiotic-associated diarrhea. In spite of expanded use of clindamycin in bone infections, the adverse reactions of this antibiotic are minor. Polyarthritis is a rare adverse effect of this antibiotic. In this case report, we studied a 75-year-old male patient with past history of drop attack and subdural hematoma who developed skull osteomyelitis after the surgery. After two weeks of intravenous antibiotic therapy, wound discharge was stopped and the patient was discharged from the hospital with the maintenance oral antibiotic therapy including clindamycin 300 mg q8 h, ciprofloxacin 500 mg q12 h and rifampin 600 mg fasting. Six days after the beginning of oral antibiotics, right wrist monoarthritis was developed. It was unresponsive to nonsteroidal anti-inflammatory drug and improved after decreased doses of clindamycin. As best as we know, monoarthritis was not reported with clindamycin previously.

Susceptibility of Escherichia coli to Bactericidal Action of Lactoperoxidase, Peroxide, and Iodide or Thiocyanate

PubMed Central

Thomas, Edwin L.; Aune, Thomas M.

1978-01-01

The bactericidal action that results from lactoperoxidase-catalyzed oxidation of iodide or thiocyanate was studied, using Escherichia coli as the test organism. The susceptibility of intact cells to bactericidal action was compared with that of cells with altered cell envelopes. Exposure to ethylenediaminetetraacetic acid, to lysozyme and ethylenediaminetetraacetic acid, or to osmotic shock were used to alter the cell envelope. Bactericidal action was greatly increased when the cells were exposed to the lactoperoxidase-peroxide-iodide system at low temperatures, low cell density, or after alteration of the cell envelope. When thiocyanate was substituted for iodide, bactericidal activity was observed only at low cell density or after osmotic shock. Low temperature and low cell density lowered the rate of destruction of peroxide by the bacteria. Therefore, competition for peroxide between the bacteria and lactoperoxidase may influence the extent of bactericidal action. Alteration of the cell envelope had only a small effect on the rate of destruction of peroxide. Instead, the increased susceptibility of these altered cells suggested that bactericidal action required permeation of a reagent through the cell envelope. In addition to altering the cell envelope, these procedures partly depleted cells of oxidizable substrates and sulfhydryl components. Adding an oxidizable substrate did not decrease the susceptibility of the altered cells. On the other hand, mild reducing agents such as sulfhydryl compounds did partly reverse bactericidal action when added after exposure of cells to the peroxidase systems. These studies indicate that alteration of the metabolism, structure, or composition of bacterial cells can greatly increase their susceptibility to peroxidase bactericidal action. PMID:348097

The many ways tissue phagocytes respond to dying cells

PubMed Central

Blander, J. Magarian

2017-01-01

Summary Apoptosis is an important component of normal tissue physiology, and the prompt removal of apoptotic cells is equally essential to avoid the undesirable consequences of their accumulation and disintegration. Professional phagocytes are highly specialized for engulfing apoptotic cells. The recent ability to track cells that have undergone apoptosis in situ has revealed a division of labor among the tissue resident phagocytes that sample them. Macrophages are uniquely programmed to process internalized apoptotic cell-derived fatty acids, cholesterol and nucleotides, as a reflection of their dominant role in clearing the bulk of apoptotic cells. Dendritic cells carry apoptotic cells to lymph nodes where they signal the emergence and expansion of highly suppressive regulatory CD4 T cells. A broad suppression of inflammation is executed through distinct phagocyte-specific mechanisms. A clever induction of negative regulatory nodes is notable in dendritic cells serving to simultaneously shut down multiple pathways of inflammation. Several of the genes and pathways modulated in phagocytes in response to apoptotic cells have been linked to chronic inflammatory and autoimmune diseases such as atherosclerosis, inflammatory bowel disease and systemic lupus erythematosus. Our collective understanding of old and new phagocyte functions after apoptotic cell phagocytosis demonstrates the enormity of ways to mediate immune suppression and enforce tissue homeostasis. PMID:28462530

The many ways tissue phagocytes respond to dying cells.

PubMed

Blander, J Magarian

2017-05-01

Apoptosis is an important component of normal tissue physiology, and the prompt removal of apoptotic cells is equally essential to avoid the undesirable consequences of their accumulation and disintegration. Professional phagocytes are highly specialized for engulfing apoptotic cells. The recent ability to track cells that have undergone apoptosis in situ has revealed a division of labor among the tissue resident phagocytes that sample them. Macrophages are uniquely programmed to process internalized apoptotic cell-derived fatty acids, cholesterol and nucleotides, as a reflection of their dominant role in clearing the bulk of apoptotic cells. Dendritic cells carry apoptotic cells to lymph nodes where they signal the emergence and expansion of highly suppressive regulatory CD4 T cells. A broad suppression of inflammation is executed through distinct phagocyte-specific mechanisms. A clever induction of negative regulatory nodes is notable in dendritic cells serving to simultaneously shut down multiple pathways of inflammation. Several of the genes and pathways modulated in phagocytes in response to apoptotic cells have been linked to chronic inflammatory and autoimmune diseases such as atherosclerosis, inflammatory bowel disease and systemic lupus erythematosus. Our collective understanding of old and new phagocyte functions after apoptotic cell phagocytosis demonstrates the enormity of ways to mediate immune suppression and enforce tissue homeostasis. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Microbiota of the Small Intestine Is Selectively Engulfed by Phagocytes of the Lamina Propria and Peyer’s Patches

PubMed Central

Morikawa, Masatoshi; Tsujibe, Satoshi; Kiyoshima-Shibata, Junko; Watanabe, Yohei; Kato-Nagaoka, Noriko; Shida, Kan; Matsumoto, Satoshi

2016-01-01

Phagocytes such as dendritic cells and macrophages, which are distributed in the small intestinal mucosa, play a crucial role in maintaining mucosal homeostasis by sampling the luminal gut microbiota. However, there is limited information regarding microbial uptake in a steady state. We investigated the composition of murine gut microbiota that is engulfed by phagocytes of specific subsets in the small intestinal lamina propria (SILP) and Peyer’s patches (PP). Analysis of bacterial 16S rRNA gene amplicon sequences revealed that: 1) all the phagocyte subsets in the SILP primarily engulfed Lactobacillus (the most abundant microbe in the small intestine), whereas CD11bhi and CD11bhiCD11chi cell subsets in PP mostly engulfed segmented filamentous bacteria (indigenous bacteria in rodents that are reported to adhere to intestinal epithelial cells); and 2) among the Lactobacillus species engulfed by the SILP cell subsets, L. murinus was engulfed more frequently than L. taiwanensis, although both these Lactobacillus species were abundant in the small intestine under physiological conditions. These results suggest that small intestinal microbiota is selectively engulfed by phagocytes that localize in the adjacent intestinal mucosa in a steady state. These observations may provide insight into the crucial role of phagocytes in immune surveillance of the small intestinal mucosa. PMID:27701454

Microbiota of the Small Intestine Is Selectively Engulfed by Phagocytes of the Lamina Propria and Peyer's Patches.

PubMed

Morikawa, Masatoshi; Tsujibe, Satoshi; Kiyoshima-Shibata, Junko; Watanabe, Yohei; Kato-Nagaoka, Noriko; Shida, Kan; Matsumoto, Satoshi

2016-01-01

Phagocytes such as dendritic cells and macrophages, which are distributed in the small intestinal mucosa, play a crucial role in maintaining mucosal homeostasis by sampling the luminal gut microbiota. However, there is limited information regarding microbial uptake in a steady state. We investigated the composition of murine gut microbiota that is engulfed by phagocytes of specific subsets in the small intestinal lamina propria (SILP) and Peyer's patches (PP). Analysis of bacterial 16S rRNA gene amplicon sequences revealed that: 1) all the phagocyte subsets in the SILP primarily engulfed Lactobacillus (the most abundant microbe in the small intestine), whereas CD11bhi and CD11bhiCD11chi cell subsets in PP mostly engulfed segmented filamentous bacteria (indigenous bacteria in rodents that are reported to adhere to intestinal epithelial cells); and 2) among the Lactobacillus species engulfed by the SILP cell subsets, L. murinus was engulfed more frequently than L. taiwanensis, although both these Lactobacillus species were abundant in the small intestine under physiological conditions. These results suggest that small intestinal microbiota is selectively engulfed by phagocytes that localize in the adjacent intestinal mucosa in a steady state. These observations may provide insight into the crucial role of phagocytes in immune surveillance of the small intestinal mucosa.

High content analysis of phagocytic activity and cell morphology with PuntoMorph.

PubMed

Al-Ali, Hassan; Gao, Han; Dalby-Hansen, Camilla; Peters, Vanessa Ann; Shi, Yan; Brambilla, Roberta

2017-11-01

Phagocytosis is essential for maintenance of normal homeostasis and healthy tissue. As such, it is a therapeutic target for a wide range of clinical applications. The development of phenotypic screens targeting phagocytosis has lagged behind, however, due to the difficulties associated with image-based quantification of phagocytic activity. We present a robust algorithm and cell-based assay system for high content analysis of phagocytic activity. The method utilizes fluorescently labeled beads as a phagocytic substrate with defined physical properties. The algorithm employs statistical modeling to determine the mean fluorescence of individual beads within each image, and uses the information to conduct an accurate count of phagocytosed beads. In addition, the algorithm conducts detailed and sophisticated analysis of cellular morphology, making it a standalone tool for high content screening. We tested our assay system using microglial cultures. Our results recapitulated previous findings on the effects of microglial stimulation on cell morphology and phagocytic activity. Moreover, our cell-level analysis revealed that the two phenotypes associated with microglial activation, specifically cell body hypertrophy and increased phagocytic activity, are not highly correlated. This novel finding suggests the two phenotypes may be under the control of distinct signaling pathways. We demonstrate that our assay system outperforms preexisting methods for quantifying phagocytic activity in multiple dimensions including speed, accuracy, and resolution. We provide a framework to facilitate the development of high content assays suitable for drug screening. For convenience, we implemented our algorithm in a standalone software package, PuntoMorph. Copyright © 2017 Elsevier B.V. All rights reserved.

Bactericidal Activity of Octenidine to Various Genospecies of Borrelia burgdorferi, Sensu Lato Spirochetes in Vitro and in Vivo.

PubMed

Tylewska-Wierzbanowska, Stanisława; Rogulska, Urszula; Lewandowska, Grażyna; Chmielewski, Tomasz

2017-07-06

The aim of our studies was to invent a reliable method for detection of the bactericidal activity of disinfectants against Borrelia burgdorferi in suspension (in vitro) and in cell line cultures (in vivo). In the suspension method, 0.01% octenidine at 20°C and 35°C was bactericidal to Borrelia afzeli; Borrelia garini, B. burgdorferi sensu stricto after 5 minutes treatment. Increase of the temperature to 35°C speed up the bactericidal effect to 1 minute. The bactericidal action of octenidine towards B. burgdorferi spirochetes growing in fibroblasts was less effective and needed a longer time to kill them than in the suspension.

Bactericidal activity of antibiotics against Legionella micdadei (Pittsburgh pneumonia agent).

PubMed Central

Dowling, J N; Weyant, R S; Pasculle, A W

1982-01-01

The bactericidal activity of five antibiotics for Legionella micdadei was determined by the construction of time-kill curves. Erythromycin, rifampin, penicillin G, cephalothin, and gentamicin were bactericidal for L. micdadei at readily achievable concentrations. The minimal bactericidal concentrations, defined as those producing 99.9% killing within 24 h, were: erythromycin, 4.6; rifampin, 0.13; penicillin G, 0.25; cephalothin, 2.5; and gentamicin, 0.25 micrograms/ml. The ratios of the minimal bactericidal to minimal inhibitory concentrations for these antibiotics ranged from 1 to 8. Thus, the poor in vivo activity of beta-lactam and aminoglycoside antibiotics against L. micdadei cannot be ascribed to a lack of killing by these agents. PMID:6927637

The Siderophore Product Ornibactin Is Required for the Bactericidal Activity of Burkholderia contaminans MS14.

PubMed

Deng, Peng; Foxfire, Adam; Xu, Jianhong; Baird, Sonya M; Jia, Jiayuan; Delgado, Keren H; Shin, Ronald; Smith, Leif; Lu, Shi-En

2017-04-15

Burkholderia contaminans MS14 was isolated from soil in Mississippi. When it is cultivated on nutrient broth-yeast extract agar, the colonies exhibit bactericidal activity against a wide range of plant-pathogenic bacteria. A bacteriostatic compound with siderophore activity was successfully purified and was determined by nuclear magnetic resonance spectroscopy to be ornibactin. Isolation of the bactericidal compound has not yet been achieved; therefore, the exact nature of the bactericidal compound is still unknown. During an attempt to isolate the bactericidal compound, an interesting relationship between the production of ornibactin and the bactericidal activity of MS14 was characterized. Transposon mutagenesis resulted in two strains that lost bactericidal activity, with insertional mutations in a nonribosomal peptide synthetase (NRPS) gene for ornibactin biosynthesis and a luxR family transcriptional regulatory gene. Coculture of these two mutant strains resulted in restoration of the bactericidal activity. Furthermore, the addition of ornibactin to the NRPS mutant restored the bactericidal phenotype. It has been demonstrated that, in MS14, ornibactin has an alternative function, aside from iron sequestration. Comparison of the ornibactin biosynthesis genes in Burkholderia species shows diversity among the regulatory elements, while the gene products for ornibactin synthesis are conserved. This is an interesting observation, given that ornibactin is thought to have the same defined function within Burkholderia species. Ornibactin is produced by most Burkholderia species, and its role in regulating the production of secondary metabolites should be investigated. IMPORTANCE Identification of the antibacterial product from strain MS14 is not the key feature of this study. We present a series of experiments that demonstrate that ornibactin is directly involved in the bactericidal phenotype of MS14. This observation provides evidence for an alternative function for ornibactin, aside from iron sequestration. Ornibactin should be further evaluated for its role in regulating the biosynthesis of secondary metabolites in other Burkholderia species. Copyright © 2017 American Society for Microbiology.

The Siderophore Product Ornibactin Is Required for the Bactericidal Activity of Burkholderia contaminans MS14

PubMed Central

Deng, Peng; Foxfire, Adam; Xu, Jianhong; Baird, Sonya M.; Jia, Jiayuan; Delgado, Keren H.; Shin, Ronald

2017-01-01

ABSTRACT Burkholderia contaminans MS14 was isolated from soil in Mississippi. When it is cultivated on nutrient broth-yeast extract agar, the colonies exhibit bactericidal activity against a wide range of plant-pathogenic bacteria. A bacteriostatic compound with siderophore activity was successfully purified and was determined by nuclear magnetic resonance spectroscopy to be ornibactin. Isolation of the bactericidal compound has not yet been achieved; therefore, the exact nature of the bactericidal compound is still unknown. During an attempt to isolate the bactericidal compound, an interesting relationship between the production of ornibactin and the bactericidal activity of MS14 was characterized. Transposon mutagenesis resulted in two strains that lost bactericidal activity, with insertional mutations in a nonribosomal peptide synthetase (NRPS) gene for ornibactin biosynthesis and a luxR family transcriptional regulatory gene. Coculture of these two mutant strains resulted in restoration of the bactericidal activity. Furthermore, the addition of ornibactin to the NRPS mutant restored the bactericidal phenotype. It has been demonstrated that, in MS14, ornibactin has an alternative function, aside from iron sequestration. Comparison of the ornibactin biosynthesis genes in Burkholderia species shows diversity among the regulatory elements, while the gene products for ornibactin synthesis are conserved. This is an interesting observation, given that ornibactin is thought to have the same defined function within Burkholderia species. Ornibactin is produced by most Burkholderia species, and its role in regulating the production of secondary metabolites should be investigated. IMPORTANCE Identification of the antibacterial product from strain MS14 is not the key feature of this study. We present a series of experiments that demonstrate that ornibactin is directly involved in the bactericidal phenotype of MS14. This observation provides evidence for an alternative function for ornibactin, aside from iron sequestration. Ornibactin should be further evaluated for its role in regulating the biosynthesis of secondary metabolites in other Burkholderia species. PMID:28188204

Cicada Wing Surface Topography: An Investigation into the Bactericidal Properties of Nanostructural Features.

PubMed

Kelleher, S M; Habimana, O; Lawler, J; O' Reilly, B; Daniels, S; Casey, E; Cowley, A

2016-06-22

Recently, the surface of the wings of the Psaltoda claripennis cicada species has been shown to possess bactericidal properties and it has been suggested that the nanostructure present on the wings was responsible for the bacterial death. We have studied the surface-based nanostructure and bactericidal activity of the wings of three different cicadas (Megapomponia intermedia, Ayuthia spectabile and Cryptotympana aguila) in order to correlate the relationship between the observed surface topographical features and their bactericidal properties. Atomic force microscopy and scanning electron microscopy performed in this study revealed that the tested wing species contained a highly uniform, nanopillar structure on the surface. The bactericidal properties of the cicada wings were investigated by assessing the viability of autofluorescent Pseudomonas fluorescens cells following static adhesion assays and targeted dead/live fluorescence staining through direct microscopic counting methods. These experiments revealed a 20-25% bacterial surface coverage on all tested wing species; however, significant bactericidal properties were observed in the M. intermedia and C. aguila species as revealed by the high dead:live cell ratio on their surfaces. The combined results suggest a strong correlation between the bactericidal properties of the wings and the scale of the nanotopography present on the different wing surfaces.

Comparative Anatomy of Phagocytic and Immunological Synapses

PubMed Central

Niedergang, Florence; Di Bartolo, Vincenzo; Alcover, Andrés

2016-01-01

The generation of phagocytic cups and immunological synapses are crucial events of the innate and adaptive immune responses, respectively. They are triggered by distinct immune receptors and performed by different cell types. However, growing experimental evidence shows that a very close series of molecular and cellular events control these two processes. Thus, the tight and dynamic interplay between receptor signaling, actin and microtubule cytoskeleton, and targeted vesicle traffic are all critical features to build functional phagosomes and immunological synapses. Interestingly, both phagocytic cups and immunological synapses display particular spatial and temporal patterns of receptors and signaling molecules, leading to the notion of “phagocytic synapse.” Here, we discuss both types of structures, their organization, and the mechanisms by which they are generated and regulated. PMID:26858721

Exploiting Uptake of Nanoparticles by Phagocytes for Cancer Treatment.

PubMed

Sheen, Mee Rie; Fiering, Steven

2017-01-01

Many cancers including ovarian, pancreatic, colon, liver, and stomach cancers are largely confined to the peritoneal cavity. Peritoneal tumors are directly accessible by intraperitoneal injections. Previously we demonstrated that intraperitoneal injection of nanoparticles and subsequent ingestion by tumor-associated phagocytes can be used to either directly impact tumors or stimulate antitumor immune responses. Here we outline methods to specifically utilize iron oxide nanoparticles with the ID8-Defb29/Vegf-A murine ovarian cancer model and discuss the tendency of phagocytes to ingest nanoparticles and the potential of phagocytes to carry nanoparticles to tumors resulting in direct killing of tumor cells or stimulate antitumor immune responses in peritoneal cancers. This basic approach can be modified as needed for different types of tumors and nanoparticles.

Protective Effect of Chitosan Oligosaccharides Against Cyclophosphamide-Induced Immunosuppression and Irradiation Injury in Mice.

PubMed

Zhai, Xingchen; Yang, Xin; Zou, Pan; Shao, Yong; Yuan, Shoujun; Abd El-Aty, A M; Wang, Jing

2018-02-01

Chitosan oligosaccharides (COS), hydrolyzed products of chitosan, was found to display various biological activities. Herein, we assessed the immunostimulatory activity of COS both in in vitro and in vivo studies. In vitro cytotoxicity studies to murine macrophage RAW264.7 revealed that COS is safe even at the maximum tested concentration of 1000 μg/mL. It also stimulates the production of nitric oxide (NO) and tumor necrosis factor (TNF-α) and enhances the phagocytosis in COS-stimulated RAW264.7. We have shown that the COS could significantly (P < 0.05) restore the reduced immune organs indices, phagocytic index, lymphocyte proliferation, natural killer cell activity, and antioxidant enzyme activities in a cyclophosphamide-induced immunosuppressed mice model. COS can also improve the survival rate in irradiation injury mice and significantly (P < 0.05) increased the spleen indices and up-regulates the CD4+/CD8+ ratio in splenocytes. In sum, the aforementioned results suggest that COS might has the potential to be used as an immunostimulatory agent in patients with immune dysfunctions or be a model for functional food development. COS might has the potential to be used as an immunostimulatory agent in patients with immune dysfunctions or be a model for functional food development. © 2018 Institute of Food Technologists®.

The biological function of antibodies induced by the RTS,S/AS01 malaria vaccine candidate is determined by their fine specificity.

PubMed

Chaudhury, Sidhartha; Ockenhouse, Christian F; Regules, Jason A; Dutta, Sheetij; Wallqvist, Anders; Jongert, Erik; Waters, Norman C; Lemiale, Franck; Bergmann-Leitner, Elke

2016-05-31

Recent vaccine studies have shown that the magnitude of an antibody response is often insufficient to explain efficacy, suggesting that characteristics regarding the quality of the antibody response, such as its fine specificity and functional activity, may play a major role in protection. Previous studies of the lead malaria vaccine candidate, RTS,S, have shown that circumsporozoite protein (CSP)-specific antibodies and CD4(+) T cell responses are associated with protection, however the role of fine specificity and biological function of CSP-specific antibodies remains to be elucidated. Here, the relationship between fine specificity, opsonization-dependent phagocytic activity and protection in RTS,S-induced antibodies is explored. A new method for measuring the phagocytic activity mediated by CSP-specific antibodies in THP-1 cells is presented and applied to samples from a recently completed phase 2 RTS,S/AS01 clinical trial. The fine specificity of the antibody response was assessed using ELISA against three antigen constructs of CSP: the central repeat region, the C-terminal domain and the full-length protein. A multi-parameter analysis of phagocytic activity and fine-specificity data was carried out to identify potential correlates of protection in RTS,S. Results from the newly developed assay revealed that serum samples from RTS,S recipients displayed a wide range of robust and repeatable phagocytic activity. Phagocytic activity was correlated with full-length CSP and C-terminal specific antibody titres, but not to repeat region antibody titres, suggesting that phagocytic activity is primarily driven by C-terminal antibodies. Although no significant difference in overall phagocytic activity was observed with respect to protection, phagocytic activity expressed as 'opsonization index', a relative measure that normalizes phagocytic activity with CS antibody titres, was found to be significantly lower in protected subjects than non-protected subjects. Opsonization index was identified as a surrogate marker of protection induced by the RTS,S/AS01 vaccine and determined how antibody fine specificity is linked to opsonization activity. These findings suggest that the role of opsonization in protection in the RTS,S vaccine may be more complex than previously thought, and demonstrate how integrating multiple immune measures can provide insight into underlying mechanisms of immunity and protection.

Tissues Use Resident Dendritic Cells and Macrophages to Maintain Homeostasis and to Regain Homeostasis upon Tissue Injury: The Immunoregulatory Role of Changing Tissue Environments

PubMed Central

Lech, Maciej; Gröbmayr, Regina; Weidenbusch, Marc; Anders, Hans-Joachim

2012-01-01

Most tissues harbor resident mononuclear phagocytes, that is, dendritic cells and macrophages. A classification that sufficiently covers their phenotypic heterogeneity and plasticity during homeostasis and disease does not yet exist because cell culture-based phenotypes often do not match those found in vivo. The plasticity of mononuclear phagocytes becomes obvious during dynamic or complex disease processes. Different data interpretation also originates from different conceptual perspectives. An immune-centric view assumes that a particular priming of phagocytes then causes a particular type of pathology in target tissues, conceptually similar to antigen-specific T-cell priming. A tissue-centric view assumes that changing tissue microenvironments shape the phenotypes of their resident and infiltrating mononuclear phagocytes to fulfill the tissue's need to maintain or regain homeostasis. Here we discuss the latter concept, for example, why different organs host different types of mononuclear phagocytes during homeostasis. We further discuss how injuries alter tissue environments and how this primes mononuclear phagocytes to enforce this particular environment, for example, to support host defense and pathogen clearance, to support the resolution of inflammation, to support epithelial and mesenchymal healing, and to support the resolution of fibrosis to the smallest possible scar. Thus, organ- and disease phase-specific microenvironments determine macrophage and dendritic cell heterogeneity in a temporal and spatial manner, which assures their support to maintain and regain homeostasis in whatever condition. Mononuclear phagocytes contributions to tissue pathologies relate to their central roles in orchestrating all stages of host defense and wound healing, which often become maladaptive processes, especially in sterile and/or diffuse tissue injuries. PMID:23251037

Phagocytosis in pup and adult harbour, grey and harp seals.

PubMed

Frouin, Héloïse; Lebeuf, Michel; Hammill, Mike; Fournier, Michel

2010-04-15

Knowledge on pinniped immunology is still in its infancy. For instance, age-related and developmental aspects of the immune system in pinnipeds need to be better described. The present study examined the phagocytic activity and efficiency of harbour, grey and harp seal leukocytes. In the first part of the study, peripheral blood was collected from captive female harbour seals of various ages. Data showed an age-related decrease in phagocytosis in female harbour seals from sub-adult to adulthood. In the second part of the study, changes in phagocytosis were quantified during lactation in wild newborn harbour, grey and harp seals and in their mothers (harp and grey seals). In newborns of the same age, leukocytes of harbour and harp seals phagocytosed less than those of grey seal pups. The phagocytic activity and efficiency increased significantly from early to mid-lactation in newborn harbour seals, and from early to late lactation in newborn grey seals, which could suggest that the transfer of phagocytosis-promoting factor(s) in colostrum is an important feature of temporary protection for pups. In contrast, no changes in phagocytic activity and efficiency were observed in lactating females of the two seal species, harp and grey, examined. At late lactation, phagocytic activity in both grey and harp seal pups and phagocytic efficiency in grey seal pups were significantly higher than in their mothers. These results could reflect either the capacity of phagocytes of the newborn harp and grey seals to respond to pathogens. Results from this study suggest that the phagocytosis of the seal species examined is not fully developed at birth as it generally increases in pups during lactation. Thereafter, the phagocytic activity of seals appears to decrease throughout adulthood. Copyright 2009 Elsevier B.V. All rights reserved.

Different tissue phagocytes sample apoptotic cells to direct distinct homeostasis programs.

PubMed

Cummings, Ryan J; Barbet, Gaetan; Bongers, Gerold; Hartmann, Boris M; Gettler, Kyle; Muniz, Luciana; Furtado, Glaucia C; Cho, Judy; Lira, Sergio A; Blander, J Magarian

2016-11-24

Recognition and removal of apoptotic cells by professional phagocytes, including dendritic cells and macrophages, preserves immune self-tolerance and prevents chronic inflammation and autoimmune pathologies. The diverse array of phagocytes that reside within different tissues, combined with the necessarily prompt nature of apoptotic cell clearance, makes it difficult to study this process in situ. The full spectrum of functions executed by tissue-resident phagocytes in response to homeostatic apoptosis, therefore, remains unclear. Here we show that mouse apoptotic intestinal epithelial cells (IECs), which undergo continuous renewal to maintain optimal barrier and absorptive functions, are not merely extruded to maintain homeostatic cell numbers, but are also sampled by a single subset of dendritic cells and two macrophage subsets within a well-characterized network of phagocytes in the small intestinal lamina propria. Characterization of the transcriptome within each subset before and after in situ sampling of apoptotic IECs revealed gene expression signatures unique to each phagocyte, including macrophage-specific lipid metabolism and amino acid catabolism, and a dendritic-cell-specific program of regulatory CD4 + T-cell activation. A common 'suppression of inflammation' signature was noted, although the specific genes and pathways involved varied amongst dendritic cells and macrophages, reflecting specialized functions. Apoptotic IECs were trafficked to mesenteric lymph nodes exclusively by the dendritic cell subset and served as critical determinants for the induction of tolerogenic regulatory CD4 + T-cell differentiation. Several of the genes that were differentially expressed by phagocytes bearing apoptotic IECs overlapped with susceptibility genes for inflammatory bowel disease. Collectively, these findings provide new insights into the consequences of apoptotic cell sampling, advance our understanding of how homeostasis is maintained within the mucosa and set the stage for development of novel therapeutics to alleviate chronic inflammatory diseases such as inflammatory bowel disease.

Specific and non-overlapping functions of testosterone and 11-ketotestosterone in the regulation of professional phagocyte responses in the teleost fish gilthead seabream.

PubMed

Aguila, S; Castillo-Briceño, P; Sánchez, M; Cabas, I; García-Alcázar, A; Meseguer, J; Mulero, V; García-Ayala, A

2013-03-01

Sex hormones, both estrogens and androgens, have a strong impact on immunity in mammals. In fish, the role of androgens in immunity has received little attention and contradictory conclusions have been obtained. However, it is well known that sex steroids are involved in fish growth, osmoregulation and gonad remodelation. In this study, we examine the in vitro effects of testosterone and 11-ketotestosterone, the two main fish androgens, on the professional phagocytes of the teleost fish gilthead seabream (Sparus aurata L.). Although both testosterone and 11-ketotestosterone failed to modulate the respiratory burst of seabream phagocytes, testosterone but not 11-ketotestosterone was able to increase the phagocytic ability of non-activated phagocytes. Curiously, 11-ketotestosterone was more powerful than testosterone at inducing the expression of its own receptor, namely androgen receptor b (ARb), in acidophilic granulocytes (AGs), but none of them affected the basal ARb expression levels in macrophages (MØ). Furthermore, although physiological concentrations of testosterone exerted a pro-inflammatory effect on both AGs and MØs, 11-ketotestosterone showed an anti-inflammatory effect in AGs and a strong pro-inflammatory effect in MØs. Interestingly, both androgens modulated the expression of toll-like receptors in these two immune cell types, suggesting that androgens might regulate the sensitivity of phagocytes to pathogens and damage signals. Testosterone and 11-ketotestosterone have a competitive effect, at least, on the modulation of the expression of some genes. Therefore, our results show for the first time a non-overlapping role for testosterone and 11-ketotestosterone in the regulation of professional phagocyte functions in fish. Copyright © 2012 Elsevier Ltd. All rights reserved.

Single sea urchin phagocytes express messages of a single sequence from the diverse Sp185/333 gene family in response to bacterial challenge.

PubMed

Majeske, Audrey J; Oren, Matan; Sacchi, Sandro; Smith, L Courtney

2014-12-01

Immune systems in animals rely on fast and efficient responses to a wide variety of pathogens. The Sp185/333 gene family in the purple sea urchin, Strongylocentrotus purpuratus, consists of an estimated 50 (±10) members per genome that share a basic gene structure but show high sequence diversity, primarily due to the mosaic appearance of short blocks of sequence called elements. The genes show significantly elevated expression in three subpopulations of phagocytes responding to marine bacteria. The encoded Sp185/333 proteins are highly diverse and have central effector functions in the immune system. In this study we report the Sp185/333 gene expression in single sea urchin phagocytes. Sea urchins challenged with heat-killed marine bacteria resulted in a typical increase in coelomocyte concentration within 24 h, which included an increased proportion of phagocytes expressing Sp185/333 proteins. Phagocyte fractions enriched from coelomocytes were used in limiting dilutions to obtain samples of single cells that were evaluated for Sp185/333 gene expression by nested RT-PCR. Amplicon sequences showed identical or nearly identical Sp185/333 amplicon sequences in single phagocytes with matches to six known Sp185/333 element patterns, including both common and rare element patterns. This suggested that single phagocytes show restricted expression from the Sp185/333 gene family and infers a diverse, flexible, and efficient response to pathogens. This type of expression pattern from a family of immune response genes in single cells has not been identified previously in other invertebrates. Copyright © 2014 by The American Association of Immunologists, Inc.

Assessment of immune response to meningococcal disease: comparison of a whole-blood assay and the serum bactericidal assay.

PubMed

Ison, C A; Anwar, N; Cole, M J; Galassini, R; Heyderman, R S; Klein, N J; West, J; Pollard, A J; Morley, S; Levin and the Meningococcal, R e

1999-10-01

A whole-blood assay (WBA), which assesses the complete bactericidal activity of blood, was compared with the serum bactericidal assay (SBA), which measures antibody and complement mediated cell lysis. Twenty children infected with serogroup B strains and 25 infected with serogroup C strains were studied 8-12 weeks after disease, and 29 healthy children were used as controls. The infecting strain (convalescent children only) and two reference strains, MC58 (B:15:P1.7, 16) and NCTC 8554 (C:NT:P1.5) were used. In children previously infected with a serogroup B strain, bactericidal activity was detected in 95% and 85% to their infecting strain by the WBA (>50% killing) and the SBA (s), respectively. Bactericidal activity to the reference serogroup B and C strain was detected by WBA in 70 and 75% of children, respectively, and the SBA in 45% and 20%. In contrast bactericidal activity was detected to both serogroup C strains in >80% of children previously infected with a serogroup C strain using either assay and in 48% (WBA) and 20% (SBA) to the reference serogroup B strain. Levels of bactericidal activity were detectable in fewer control children. Children convalescing from meningococcal disease develop an immune response to their infecting strain, detectable by both the WBA and SBA, which is independent of age. However, the WBA appears to be a more sensitive measure of bactericidal activity to heterologous strains than the SBA. Copyright 1999 Academic Press.

Translational Advancement of Somatostatin Gene Delivery for Disease Modification and Cognitive Sparing in Intractable Epilepsy

DTIC Science & Technology

2015-09-01

morphological analysis revealed significantly more activated (p < 0.001) and highly activated ( phagocytic ; p < 0.05) microglia in the dentate gyri of...process with small cell bodies (Figure 10A). Activated microglia exhibit less ramified processes and larger nuclei (Figure 10B) and phagocytic microglia...significantly increases in the dentate gyri of kindled rats along with the total number of highly activated or phagocytic microglia. We are currently

Effects of in vivo exposure of Mya arenaria to organic and inorganic mercury on phagocytic activity of hemocytes.

PubMed

Fournier, M; Pellerin, J; Clermont, Y; Morin, Y; Brousseau, P

2001-03-28

Marine bivalves are aquatic invertebrate organisms which can be used as bioindicators in environmental monitoring. In vivo effects of mercuric chloride (HgCl(2)) and methylmercury (CH(3)HgCl) on phagocytic function of Mya arenaria hemocytes were evaluated in this study. Clams were exposed to single metal in water for up to 28 days at concentrations ranging from 10(-9) to 10(-5) M. Phagocytic activity of hemocytes was determined by uptake of fluorescent microspheres and flow cytometry. All clams exposed to 10(-5) M HgCl(2) died by day 7 of exposure. The viability of hemocytes was decreased only in clams exposed to 10(-6) M HgCl(2) for 28 days. A significant decrease in phagocytic activity of hemocytes was observed in clams exposed to 10(-6) M of HgCl(2) for 28 days. A similar pattern was observed with CH(3)HgCl, but at an earlier time. Chemical analysis performed on the tissues of the animals clearly show a greater uptake of the organic form of mercury by clams. Furthermore, a clear correlation was established between body burden of mercury and effects on phagocytic activity of hemocytes. Overall, the results of this study show that both speciations of mercury inhibited phagocytic function of Mya arenaria hemocytes following in vivo exposures.

Influence of the acute alcoholism on the phagocytic function of the mononuclear phagocytic system

PubMed Central

Sabino, KR; Petroianu, A; Alberti, LR

2011-01-01

Rationale:Alcoholics are more likely to have infections, mainly in the respiratory system. Alcohol seems to inhibit the immune system. Despite the extensive literature related to alcoholism, data related to the immune system are still not conclusive. Objective: The purpose of this study was to verify the influence of acute alcohol intake on colloid distribution in the organs of the mononuclear phagocyte system. Methods and Results: Thirteen male Swiss mice were divided into two groups: Group 1 (n = 5) – control, and Group 2 (n = 8) – animals that received 0.5 ml ethanol 50%, 30 minutes before the experiment. Colloidal sulphur labeled with ⁸⁸mTc was used to evaluate colloid distribution in the liver, spleen and lungs. Colloid clearance was assessed as well. A gamma camera was used to measure the radioactivity of these organs and of a blood clot. No difference was found in the presence of colloid in the organs of both groups. The liver showed the highest phagocytic intake, followed by the spleen and lungs (p = 0.021 for Group 1 and p = 0.003 for Group 2). A minimum amount of radiation remained in the blood of both groups. Discussion: According to the experiential conditions of this work, acute ingestion of alcohol did not interfere with the phagocytic function of the mononuclear phagocyte system in mice. PMID:22514578

Sword and shield: linked group B streptococcal beta-hemolysin/cytolysin and carotenoid pigment function to subvert host phagocyte defense.

PubMed

Liu, George Y; Doran, Kelly S; Lawrence, Toby; Turkson, Nicole; Puliti, Manuela; Tissi, Luciana; Nizet, Victor

2004-10-05

Group B Streptococcus (GBS) is a major cause of pneumonia, bacteremia, and meningitis in neonates and has been found to persist inside host phagocytic cells. The pore-forming GBS beta-hemolysin/cytolysin (betaH/C) encoded by cylE is an important virulence factor as demonstrated in several in vivo models. Interestingly, cylE deletion results not only in the loss of betaH/C activity, but also in the loss of a carotenoid pigment of unknown function. In this study, we sought to define the mechanism(s) by which cylE may contribute to GBS phagocyte resistance and increased virulence potential. We found that cylE-deficient GBS was more readily cleared from a mouse's bloodstream, human whole blood, and isolated macrophage and neutrophil cultures. Survival was linked to the ability of betaH/C to induce cytolysis and apoptosis of the phagocytes. At a lower bacterial inoculum, cylE also contributed to enhanced survival within phagocytes that was attributed to the ability of carotenoid to shield GBS from oxidative damage. In oxidant killing assays, cylE mutants were shown to be more susceptible to hydrogen peroxide, hypochlorite, superoxide, and singlet oxygen. Together, these data suggest a mechanism by which the linked cylE-encoded phenotypes, betaH/C (sword) and carotenoid (shield), act in partnership to thwart the immune phagocytic defenses.

Immunomodulation of Homeopathic Thymulin 5CH in a BCG-Induced Granuloma Model

PubMed Central

Bonamin, Leoni Villano; Sato, Cesar; Zalla Neto, Ruggero; Morante, Graziela; Cardoso, Thayná Neves; de Santana, Fabiana Rodrigues; Coelho, Cideli de Paula; Osugui, Lika; Popi, Ana Flavia; Hurtado, Elizabeth Cristina Perez; Mariano, Mario

2013-01-01

The present study analyzed the immune modulation mechanisms of thymulin 5CH in a granuloma experimental model. Male adult Balb/c mice were inoculated with BCG into the footpad to induce granuloma, which was quantitatively evaluated. The phenotypic characterization of phagocyte, T- and B-lymphocyte populations in the peritoneum, and local lymph node was done by flow cytometry. During all experimental periods, thymulin 5CH and vehicle (control) were given ad libitum to mice, diluted into the drinking water (1.6 × 10−17 M). After 7 days from inoculation, thymulin-treated mice presented reduction in the number of epithelioid cytokeratine-positive cells (P = 0.0001) in the lesion, in relation to young phagocytes. After 21 days, the differentiation of B1 peritoneal stem cells into phagocytes reached the peak, being higher in thymulin-treated mice (P = 0.0001). Simultaneously, the score of infected phagocytes in the lesion decreased (P = 0.001), and the number of B1-derived phagocytes, CD4+ and CD8+ T lymphocytes in the local lymph node increased in relation to control (P = 0.0001). No difference was seen on the CD25+ Treg cells. The results show that thymulin 5CH treatment is able to improve the granuloma inflammatory process and the infection remission, by modulating local and systemic phagocyte differentiation. PMID:23431344

Flow microfluorometric analysis of phagocyte degranulation in bacteria-infected whole human blood cell cultures

NASA Astrophysics Data System (ADS)

Kravtsov, Alexander L.; Bobyleva, Elena V.; Grebenyukova, Tatyana P.; Kuznetsov, Oleg S.; Kulyash, Youri V.

2002-07-01

A quantitative flow microfluorometric method was used to study the intensity of human blood phagocyte degranulation in response to viable staphylococcus aureus or Yersinia pestis cells. Microorganisms were added directly to defibrinated whole blood. Uninfected and infected blood samples were incubated at 37 degrees C to 8 h. The results were recorded in dynamics after the staining of whole blood with acridine orange solution. Lymphocytes with a low azurophilic granule per cell content were discriminated from phagocytes by the measurement of single cell red cytoplasmic granule fluorescence. 30,000 cells in each sample were examined. S. aureus cells caused a dose-dependent decrease in the number of phagocytes having a high red cytoplasmic fluorescence intensity and a corresponding increase in the weakly fluorescence cell population. In the presence of an initial S. aureus-to-phagocyte ratio more than 1:1, degranulation was measured after 3 h of incubation and to 8 h the percentage of degranulated phagocytes was at least 100 percent Y. pestis cells grown for 48 h at 28 degrees C caused at same condition as the degranulation only about 50 percent of cells. Y.pestis EV cells preincubated in broth for 12 h at 37 degrees C did no stimulate the phahocyte degranulation. The results of these studies suggest that analysis of cell populations via flow microfluorimeter technology may be a powerful tool in analysis bacterial infection.

The modulatory role of cytokines IL-4 and IL-17 in the functional activity of phagocytes in diabetic pregnant women.

PubMed

Fagundes, Danny L G; França, Eduardo L; Gonzatti, Michelangelo B; Rugde, Marilza V C; Calderon, Iracema M P; Honorio-França, Adenilda C

2018-01-01

The study investigated the role of cytokines IL-4 and IL-17 in the modulation of the functional activity of mononuclear phagocytes in diabetic pregnant women with hyperglycemia. Sixty pregnant women were assigned to the following groups: nondiabetic (ND), mild gestational hyperglycemia (MGH), gestational diabetes mellitus (GDM), or type 2 diabetes mellitus (DM2). The functional activity of phagocytes from maternal blood, cord blood, and colostrum was assessed by determining their superoxide release, phagocytosis, microbicidal activity, and intracellular Ca 2+ release. Irrespective of glycemic status, colostrum and blood cells treated with IL-4 and IL-17 increased superoxide release in the presence of enteropathogenic Escherichia coli (EPEC). The highest phagocytosis rate was observed in cells from the DM2 group treated with IL-4. In all the groups, phagocytes from colostrum, maternal blood, and cord blood exhibited higher microbicidal activity against EPEC when treated with cytokines. IL-17 increased intracellular Ca 2+ release by colostrum phagocytes in diabetic groups. The results indicate that the IL-4 and IL-17 modulate the functional activity of phagocytes in the maternal blood, cord blood, and colostrum of diabetic mother. The natural immunity resulting from the interaction between the cells and cytokines tested may be an alternative procedure to improve the prognosis of maternal and newborn infections. © 2017 APMIS. Published by John Wiley & Sons Ltd.

[EFFICIENCY OF COMBINATION OF ROFLUMILAST AND QUERCETIN FOR CORRECTION OXYGEN- INDEPENDENT MECHANISMS AND PHAGOCYTIC ACTIVITY OF MACROPHAGE CELLS OF PATIENTS WITH ACUTE EXACERBATION OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE WHEN COMBINED WITH CORONARY HEART DISEASE].

PubMed

Gerych, P; Yatsyshyn, R

2015-01-01

Studied oxygen independent reaction and phagocytic activity of macrophage cells of patients with chronic obstructive pulmonary disease (COPD) II-III stage when combined with coronary heart disease (CHD). The increasing oxygen independent reactions monocytes and neutrophils and a decrease of the parameters that characterize the functional state of phagocytic cells, indicating a decrease in the functional capacity of macrophage phagocytic system (MPS) in patients with acute exacerbation of COPD, which runs as its own or in combination with stable coronary heart disease angina I-II. FC. Severity immunodeficiency state in terms of cellular component of nonspecific immunity in patients with acute exacerbation of COPD II-III stage in conjunction with the accompanying CHD increases with the progression of heart failure. Inclusion of basic therapy of COPD exacerbation and standard treatment of coronary artery disease and drug combinations Roflumilastand quercetin causes normalization of phagocytic indices MFS, indicating improved immune status and improves myocardial perfusion in terms of daily ECG monitoring.

Immunomagnetic isolation of pathogen-containing phagosomes and apoptotic blebs from primary phagocytes.

PubMed

Steinhäuser, Christine; Dallenga, Tobias; Tchikov, Vladimir; Schaible, Ulrich E; Schütze, Stefan; Reiling, Norbert

2014-04-02

Macrophages and polymorphonuclear neutrophils are professional phagocytes essential in the initial host response against intracellular pathogens such as Mycobacterium tuberculosis. Phagocytosis is the first step in phagocyte-pathogen interaction, where the pathogen is engulfed into a membrane-enclosed compartment termed a phagosome. Subsequent effector functions of phagocytes result in killing and degradation of the pathogen by promoting phagosome maturation, and, terminally, phago-lysosome fusion. Intracellular pathogenic microbes use various strategies to avoid detection and elimination by phagocytes, including induction of apoptosis to escape host cells, thereby generating apoptotic blebs as shuttles to other cells for pathogens and antigens thereof. Hence, phagosomes represent compartments where host and pathogen become quite intimate, and apoptotic blebs are carrier bags of the pathogen's legacy. In order to investigate the molecular mechanisms underlying these interactions, both phagosomes and apoptotic blebs are required as purified subcellular fractions for subsequent analysis of their biochemical properties. Here, we describe a lipid-based procedure to magnetically label surfaces of either pathogenic mycobacteria or apoptotic blebs for purification by a strong magnetic field in a novel free-flow system. Copyright © 2014 John Wiley & Sons, Inc.

Depletion of Phagocytic Cells during Nonlethal Plasmodium yoelii Infection Causes Severe Malaria Characterized by Acute Renal Failure in Mice

PubMed Central

Terkawi, Mohamad Alaa; Nishimura, Maki; Furuoka, Hidefumi

2016-01-01

In the current study, we examined the effects of depletion of phagocytes on the progression of Plasmodium yoelii 17XNL infection in mice. Strikingly, the depletion of phagocytic cells, including macrophages, with clodronate in the acute phase of infection significantly reduced peripheral parasitemia but increased mortality. Moribund mice displayed severe pathological damage, including coagulative necrosis in liver and thrombi in the glomeruli, fibrin deposition, and tubular necrosis in kidney. The severity of infection was coincident with the increased sequestration of parasitized erythrocytes, the systematic upregulation of inflammation and coagulation, and the disruption of endothelial integrity in the liver and kidney. Aspirin was administered to the mice to minimize the risk of excessive activation of the coagulation response and fibrin deposition in the renal tissue. Interestingly, treatment with aspirin reduced the parasite burden and pathological lesions in the renal tissue and improved survival of phagocyte-depleted mice. Our data imply that the depletion of phagocytic cells, including macrophages, in the acute phase of infection increases the severity of malarial infection, typified by multiorgan failure and high mortality. PMID:26755155

Effects of β-glucans from Coriolus versicolor on macrophage phagocytosis are related to the Akt and CK2/Ikaros.

PubMed

Kang, Se Chan; Koo, Hyun Jung; Park, Sulkyung; Lim, Jung Dae; Kim, Ye-Jin; Kim, Taeseong; Namkoong, Seung; Jang, Ki-Hyo; Pyo, Suhkneung; Jang, Seon-A; Sohn, Eun-Hwa

2013-06-01

Coriolus versicolor has been known to be an immune stimulator effects. For further understanding of the phagocytic activity and the intracellular mechanisms of β-glucan from C. versicolor (CVG), we examined the phagocytic activity, phosphorylation of Akt and CK2, nucleus translocation of p65 and Ikaros activity in β-glucan-treated macrophages using RT-PCR, western blotting, and IP assay. The role of Ikaros in regulating phagocytic effects of CVG was also determined using Ikaros dominant negative isoform cells. This study suggests that CK2/Ikaros are positive regulators and novel signaling pathway involved in phagocytosis and contributes to elucidating the mechanism underlying phagocytic activity induced by β-glucan. Copyright © 2013 Elsevier B.V. All rights reserved.

Every day I'm rufflin': Calcium sensing and actin dynamics in the growth factor-independent membrane ruffling of professional phagocytes.

PubMed

Schlam, Daniel; Canton, Johnathan

2017-04-03

Professional phagocytes continuously extend dynamic, actin-driven membrane protrusions. These protrusions, often referred to as membrane ruffles, serve a critical role in the essential phagocyte processes of macropinocytosis and phagocytosis. Small GTPases, such as RAC1/2, spatially and temporally regulate membrane ruffle formation. We have recently shown that extracellular calcium regulates the elaboration of membrane ruffles primarily through the synthesis of phosphatidic acid (PtdOH) at the plasma membrane. RAC1/2 guanine nucleotide exchange factors harbouring polybasic stretches are recruited by PtdOH to sites of ruffle formation. Here we discuss our findings and offer perspectives on how the regulation of dynamic actin structures at the plasma membrane by small GTPases is a critical component of phagocyte function.

Bactericidal catechins damage the lipid bilayer.

PubMed

Ikigai, H; Nakae, T; Hara, Y; Shimamura, T

1993-04-08

The mode of antibacterial action of, the green tea (Camellia sinensis) extracts, (-)-epigallocatechin gallate (EGCg) and (-)-epicatechin (EC) was investigated. Strong bactericidal EGCg caused leakage of 5,6-carboxyfluorescein from phosphatidylcholine liposomes (PC), but EC with very weak bactericidal activity caused little damage to the membrane. Phosphatidylserine and dicetyl phosphate partially protected the membrane from EGCg-mediated damage when reconstituted into the liposome membrane with PC. EGCg, but not EC, caused strong aggregation and NPN-fluorescence quenching of PC-liposomes and these actions were markedly lowered in the presence of negatively charged lipids. These results show that bactericidal catechins primarily act on and damage bacterial membranes. The observation that Gram-negative bacteria are more resistant to bactericidal catechins than Gram-positive bacteria can be explained to some extent by the presence of negatively charged lipopolysaccharide.

Genetics Home Reference: chronic granulomatous disease

MedlinePlus

... is primarily active in immune system cells called phagocytes. These cells catch and destroy foreign invaders such as bacteria and fungi. Within phagocytes, NADPH oxidase is involved in the production of ...

Targeting the Immune System’s Natural Response to Cell Death to Improve Therapeutic Response in Breast Cancers

DTIC Science & Technology

2015-07-01

epithelial cells (MECs) are cleared from the mammary gland through efferocytosis, a process by which macrophages and other phagocytes recognize, bind to...chronic inflammatory lung disease. Chest. 2006;129(6):1673–1682. 48. deCathelineau AM, Henson PM. The final step in programmed cell death: phagocytes ...carry apoptotic cells to the grave. Essays Biochem. 2003;39:105–117. 49. Erwig LP, Henson PM. Clearance of apop- totic cells by phagocytes . Cell Death

The Biological Function of Antibodies Induced by the RTS,S/AS01 Malaria Vaccine Candidate is Determined by Their Fine Specificity

DTIC Science & Technology

2016-05-31

specificity, opsonization‑dependent phagocytic activity and protection in RTS,S‑induced antibodies is explored. Methods: A new method for measuring...the phagocytic activity mediated by CSP‑specific antibodies in THP‑1 cells is presented and applied to samples from a recently completed phase 2 RTS,S...repeat region, the C‑terminal domain and the full‑length protein. A multi‑parameter analysis of phagocytic activity and fine‑specific‑ ity data was

Human milk bactericidal properties: effect of lyophilization and relation to maternal factors and milk components.

PubMed

Salcedo, Jaime; Gormaz, Maria; López-Mendoza, Maria C; Nogarotto, Elisabetta; Silvestre, Dolores

2015-04-01

Lyophilization appears to be a viable method for storing human milk, assuring no microbiological contamination and preserving its health benefits and antibacterial properties. The aim of the study is to evaluate and compare the effects of different storage methods (lyophilization and freezing at -20°C and -80°C) and maternal factors (gestational length or time postpartum) upon the microbiological contents and bactericidal activity of human milk. The possible relation between bactericidal activity and the content of certain nutrients and functional components is also investigated. Microbiological content, bactericidal activity, sialic acid, and ganglioside contents, as well as protein, fat, and lactose concentrations were assessed in 125 human milk samples from 65 healthy donors in the Human Milk Bank of La Fe (Valencia, Spain). Lyophilization and storage at -80°C significantly reduced the content of mesophilic aerobic microorganisms and Staphylococcus epidermidis when compared with storage at -20°C. Bactericidal activity was not significantly modified by lyophilization when compared with freezing at either -20°C or -80°C. Bactericidal activity was not correlated with fat, protein, or lactose content, but was significantly correlated to ganglioside content. The bactericidal activity was significantly greater (P < 0.05) in mature milk and in milk from women with term delivery than in milk from early lactation (days 1-7 postpartum) and milk from women with preterm delivery, respectively. Lyophilization and storage at -80°C of human milk yields similar results and are superior to storage at -20C with regard to microbial and bactericidal capacities, being a feasible alternative for human milk banks.

Evaluation of bactericidal effects of low-temperature nitrogen gas plasma towards application to short-time sterilization.

PubMed

Kawamura, Kumiko; Sakuma, Ayaka; Nakamura, Yuka; Oguri, Tomoko; Sato, Natsumi; Kido, Nobuo

2012-07-01

To develop a novel low-temperature plasma sterilizer using pure N(2) gas as a plasma source, we evaluated bactericidal ability of a prototype apparatus provided by NGK Insulators. After determination of the sterilizing conditions without the cold spots, the D value of the BI of Geobacillus stearothermophilus endospores on the filter paper was determined as 1.9 min. However, the inactivation efficiency of BI carrying the same endospores on SUS varied to some extent, suggesting that the bactericidal effect might vary by materials of sterilized instruments. Staphylococcus aureus and Escherichia coli were also exposed to the N(2) gas plasma and confirmed to be inactivated within 30 min. Through the evaluation of bactericidal efficiency in a sterilization bag, we concluded that the UV photons in the plasma and the high-voltage pulse to generate the gas plasma were not concerned with the bactericidal effect of the N(2) gas plasma. Bactericidal effect might be exhibited by activated nitrogen atoms or molecular radicals. © 2012 The Societies and Blackwell Publishing Asia Pty Ltd.

Polyhexamethylene guanidine hydrochloride shows bactericidal advantages over chlorhexidine digluconate against ESKAPE bacteria.

PubMed

Zhou, Zhongxin; Wei, Dafu; Lu, Yanhua

2015-01-01

More information regarding the bactericidal properties of polyhexamethylene guanidine hydrochloride (PHMG) against clinically important antibiotic-resistant ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens needs to be provided for its uses in infection control. The bactericidal properties of PHMG and chlorhexidine digluconate (CHG) were compared based on their minimum inhibitory concentrations (MICs), minimum bactericidal concentrations, and time-course-killing curves against clinically important antibiotic-susceptible and antibiotic-resistant ESKAPE pathogens. Results showed that PHMG exhibited significantly higher bactericidal activities against methicillin-resistant Staphylococcus aureus, carbapenem-resistant Klebsiella pneumoniae, and ceftazidime-resistant Enterobacter spp. than CHG. A slight bactericidal advantage over CHG was obtained against vancomycin-resistant Enterococcus faecium, ciprofloxacin- and levofloxacin-resistant Acinetobacter spp., and multidrug-resistant Pseudomonas aeruginosa. In previous reports, PHMG had higher antimicrobial activity against almost all tested Gram-negative bacteria and several Gram-positive bacteria than CHG using MIC test. These studies support the further development of covalently bound PHMG in sterile-surface materials and the incorporation of PHMG in novel disinfectant formulas. © 2014 International Union of Biochemistry and Molecular Biology, Inc.

Bactericidal activity against coagulase-negative staphylococci is impaired in infants receiving long-term parenteral nutrition.

PubMed

Okada, Y; Klein, N J; van Saene, H K; Webb, G; Holzel, H; Pierro, A

2000-02-01

To examine the role of total parenteral nutrition (TPN) in predisposing infants to infection caused by coagulase-negative staphylococci. Total parenteral nutrition is an important means of providing essential nutrients to newborn infants. However, its use has been associated with complications, particularly infection caused by coagulase-negative staphylococci. Recent data suggest that TPN may modulate immune function; however, reports directly indicating impaired immunity against coagulase-negative staphylococci during TPN are limited. Study 1 involved 31 infants younger than 4 months who had undergone surgery and were not receiving antibiotics; 20 were receiving TPN and 11 were receiving a normal enteral diet. An in vitro whole blood model was used to measure the host bactericidal activity against coagulase-negative staphylococci. Bacterial killing and phagocytosis were measured after a 45-minute challenge with viable coagulase-negative staphylococci. In study 2, whole blood killing and intracellular killing of coagulase-negative staphylococci were measured in five newborn infants (younger than 2 months) who were receiving long-term TPN (>10 days), five control infants receiving a normal enteral diet, and five healthy adults. In study 1, infants receiving a normal enteral diet showed a high capacity to ingest and kill coagulase-negative staphylococci. In contrast, the blood of infants receiving long-term TPN showed a reduction in coagulase-negative staphylococci phagocytosis and killing. There were significant negative linear correlations between the duration of TPN and killing of coagulase-negative staphylococci and phagocytosis of coagulase-negative staphylococci. In study 2, infants receiving long-term TPN had lower whole blood killing and intracellular killing than infants receiving a normal enteral diet and healthy adult volunteers. These data seem to indicate a neutrophil dysfunction mediated by TPN in infancy. Host defense mechanisms, including phagocytosis and killing of coagulase-negative staphylococci, are impaired during long-term TPN. The impaired bactericidal activity seems to be related to defective intracellular killing in neutrophils. These findings may explain the high rate of septicemia caused by coagulase-negative staphylococci in infants receiving TPN.

THE CONTRIBUTION OF TYRO3 FAMILY RECEPTOR TYROSINE KINASES TO THE HETEROGENEITY OF APOPTOTIC CELL UPTAKE BY MONONUCLEAR PHAGOCYTES

PubMed Central

Curtis, Jeffrey L.; Todt, Jill C.; Hu, Bin; Osterholzer, John J.; Freeman, Christine M.

2014-01-01

Mononuclear phagocytes comprise a mobile, broadly dispersed and highly adaptable system that lies at the very epicenter of host defense against pathogens and the interplay of the innate and adaptive arms of immunity. Understanding the molecular mechanisms that control the response of mononuclear phagocytes to apoptotic cells and the anti-inflammatory consequences of that response is an important goal with implications for multiple areas of biomedical sciences. This review details current understanding of the heterogeneity of apoptotic cell uptake by different members of the mononuclear phagocyte family in humans and mice. It also recounts the unique role of the Tyro3 family of receptor tyrosine kinases, best characterized for Mertk, in the signal transduction leading both to apoptotic cell ingestion and the anti-inflammatory effects that result. PMID:19273223

M-ficolin concentrations in cord blood are related to circulating phagocytes and to early-onset sepsis.

PubMed

Schlapbach, Luregn J; Kjaer, Troels R; Thiel, Steffen; Mattmann, Maika; Nelle, Mathias; Wagner, Bendicht P; Ammann, Roland A; Aebi, Christoph; Jensenius, Jens C

2012-04-01

The pattern-recognition molecule M-ficolin is synthesized by monocytes and neutrophils. M-ficolin activates the complement system in a manner similar to mannan-binding lectin (MBL), but little is known about its role in host defense. Neonates are highly vulnerable to bacterial sepsis, in particular, due to their decreased phagocytic function. M-ficolin cord blood concentration was positively correlated with the absolute phagocyte count (ρ 0.51, P < 0.001) and with immature/total neutrophil ratio (ρ 0.34, P < 0.001). When comparing infants with sepsis and controls, a high M-ficolin cord blood concentration (>1,000 ng/ml) was associated with early-onset sepsis (EOS) (multivariate odds ratio 10.92, 95% confidence interval 2.21-54.02, P = 0.003). Experimental exposure of phagocytes isolated from adult donors to Escherichia coli resulted in a significant time- and dose-dependent release of M-ficolin. In conclusion, M-ficolin concentrations were related to circulating phagocytes and EOS. Our results indicate that bacterial sepsis can trigger M-ficolin release by phagocytes. Future studies should investigate whether M-ficolin may be used as a marker of neutrophil activation during invasive infections. We investigated M-ficolin in 47 infants with culture-positive sepsis during the first 30 days of life (13 with EOS and in 94 matched controls. M-ficolin was measured in cord blood using time-resolved immunofluorometric assay (TRIFMA). Multivariate logistic regression was performed.

Silver ion bactericide system. [for Space Shuttle Orbiter potable water

NASA Technical Reports Server (NTRS)

Jasionowski, W. J.; Allen, E. T.

1974-01-01

Description of a preliminary flight prototype system which uses silver ions as the bactericide to preserve sterility of the water used for human consumption and hygiene in the Space Shuttle Orbiter. The performance of silver halide columns for passively dosing fuel cell water with silver ions is evaluated. Tests under simulated Orbiter mission conditions show that silver ion doses of 0.05 ppm are bactericidal for Pseudomonas aeruginosa and Type IIIa, the two bacteria found in Apollo potable water systems. The design of the Advance Prototype Silver Ion Water Bactericide System now under development is discussed.

KINETICS OF THE ACTION OF AMPICILLIN ON ESCHERICHIA COLI

PubMed Central

Seligman, Stephen J.; Hewitt, William L.

1963-01-01

Seligman, Stephen J. (University of California, Los Angeles) and William L. Hewitt. Kinetics of the action of ampicillin on Escherichia coli. J. Bacteriol. 85:1160–1164. 1963.—The curve of the number of viable Escherichia coli after exposure to ampicillin can be divided into three phases: a lag phase, a rapid bactericidal phase, and a slow bactericidal phase. Some of the variables affecting the magnitude of the first two of these phases were investigated. Progressive lowering of drug concentration resulted in prolongation of the lag phase and decrease in slope and extent of the rapid bactericidal phase. The production of elongated gram-negative forms and the emergence of a mutant with increased penicillinase activity complicated interpretation of the lower dose curves. With sufficient drug concentration, the length of the lag phase and the slope of the rapid bactericidal curve were independent of the size of inoculum up to 108 organisms. Varying pH revealed that maximal activity, as measured by the shortest lag phase and steepest slope of the rapid bactericidal phase, was present at slightly acid pH levels. Increasing pH resulted principally in prolongation of lag phase. With greater acidity, decrease in slope of the rapid bactericidal phase was more prominent. Cultures studied under conditions of lessened metabolic activity exhibited prolonged lag phase and decreased slope and extent of rapid bactericidal phase. PMID:14044010

Isolation and functional characteristics of adherent phagocytic cells from mouse Peyer's patches.

PubMed Central

MacDonald, T T; Carter, P B

1982-01-01

Attempts were made to isolate adherent phagocytic cells (macrophages) from mouse Peyer's patch cell suspensions. Cell suspensions prepared by teasing apart the Peyer's patches contained no adherent phagocytic cells. However, if Peyer's patch fragments were treated with collagenase to disrupt the tissue matrix, cells prepared in this way contained a subpopulation of adherent phagocytic cells. These cells comprised only 0.1-0.2% of the total nucleated cell population of the Peyer's patch. Similar cells could also be isolated from the Peyer's patches of germ-free mice, but as judged by their ability to ingest opsonized erythrocytes, these cells were less activated than cells from the Peyer's patches of normal mice. Adherent cells from the Peyer's patches of normal mice could present antigen (ovalbumin) to T cells, and Peyer's patches cell suspensions containing adherent cells could be stimulated in vitro to produce an anti-sheep red blood cell plaque-forming cell response in the absence of 2-mercaptoethanol. These studies show that although the frequency of phagocytic adherent cells is extremely low in Peyer's patches, these cells have functions consistent with that of adherent cells in other lymphoid tissues. PMID:7068173

Mechanisms of phagocytosis and host clearance of Pseudomonas aeruginosa

PubMed Central

Lovewell, Rustin R.; Patankar, Yash R.

2014-01-01

Pseudomonas aeruginosa is an opportunistic bacterial pathogen responsible for a high incidence of acute and chronic pulmonary infection. These infections are particularly prevalent in patients with chronic obstructive pulmonary disease and cystic fibrosis: much of the morbidity and pathophysiology associated with these diseases is due to a hypersusceptibility to bacterial infection. Innate immunity, primarily through inflammatory cytokine production, cellular recruitment, and phagocytic clearance by neutrophils and macrophages, is the key to endogenous control of P. aeruginosa infection. In this review, we highlight recent advances toward understanding the innate immune response to P. aeruginosa, with a focus on the role of phagocytes in control of P. aeruginosa infection. Specifically, we summarize the cellular and molecular mechanisms of phagocytic recognition and uptake of P. aeruginosa, and how current animal models of P. aeruginosa infection reflect clinical observations in the context of phagocytic clearance of the bacteria. Several notable phenotypic changes to the bacteria are consistently observed during chronic pulmonary infections, including changes to mucoidy and flagellar motility, that likely enable or reflect their ability to persist. These traits are likewise examined in the context of how the bacteria avoid phagocytic clearance, inflammation, and sterilizing immunity. PMID:24464809

Mechanisms of phagocytosis and host clearance of Pseudomonas aeruginosa.

PubMed

Lovewell, Rustin R; Patankar, Yash R; Berwin, Brent

2014-04-01

Pseudomonas aeruginosa is an opportunistic bacterial pathogen responsible for a high incidence of acute and chronic pulmonary infection. These infections are particularly prevalent in patients with chronic obstructive pulmonary disease and cystic fibrosis: much of the morbidity and pathophysiology associated with these diseases is due to a hypersusceptibility to bacterial infection. Innate immunity, primarily through inflammatory cytokine production, cellular recruitment, and phagocytic clearance by neutrophils and macrophages, is the key to endogenous control of P. aeruginosa infection. In this review, we highlight recent advances toward understanding the innate immune response to P. aeruginosa, with a focus on the role of phagocytes in control of P. aeruginosa infection. Specifically, we summarize the cellular and molecular mechanisms of phagocytic recognition and uptake of P. aeruginosa, and how current animal models of P. aeruginosa infection reflect clinical observations in the context of phagocytic clearance of the bacteria. Several notable phenotypic changes to the bacteria are consistently observed during chronic pulmonary infections, including changes to mucoidy and flagellar motility, that likely enable or reflect their ability to persist. These traits are likewise examined in the context of how the bacteria avoid phagocytic clearance, inflammation, and sterilizing immunity.

[Effect of hydroxyethyl starch, oxypolygelatin and human albumin on the phagocytic function of the reticuloendothelial system in healthy subjects].

PubMed

Lenz, G; Hempel, V; Junger, H; Werle, H; Buckenmaier, P

1986-07-01

RES phagocytic function was determined in healthy volunteers prior to and up to 5 h after application of 10 ml/kg body weight of 6% hydroxyethyl starch (450,000; 0.7), 5.5% oxypolygelatin (30,000), or 5.0% human albumin solution. Phagocytosis (phagocytic index K) was evaluated in vivo by intravascular lipid clearance (Lipofundin clearance test). Immediately after infusion, the phagocytic rate increased by 30% in the hydroxyethyl starch group (n = 10; p less than 0.05), 14% in the oxypolygelatin group (n = 10; ns), and 24% in the albumin group (n = 8; ns). 2 h after infusion phagocytosis was still increased by 35% in the hydroxyethyl starch group (n = 10; p less than 0.05), by 18% in the oxypolygelatin group (n = 10; ns), and 13% in the albumin group (n = 8; ns). 5 h after infusion, K values had returned to normal in the albumin group (n = 4), but were still increased by 40% in the hydroxyethyl starch group (n = 4; ns). No statistically significant differences could be established among the 3 groups. The increase in the phagocytic rate, particularly after application of hydroxyethyl starch, might be explained by a dilution effect.

Molecular cloning of rock bream (Oplegnathus fasciatus) tumor necrosis factor-alpha and its effect on the respiratory burst activity of phagocytes.

PubMed

Kim, Min Sun; Hwang, Yoon Jung; Yoon, Ki Joon; Zenke, Kosuke; Nam, Yoon Kwon; Kim, Sung Koo; Kim, Ki Hong

2009-11-01

Rock bream (Oplegnathus fasciatus) tumor necrosis factor-alpha (rbTNF-alpha) gene was cloned, recombinantly produced, and the effect of the recombinant rbTNF-alpha on the respiratory burst activity of rock bream phagocytes was analyzed. Structurally, genomic DNA of rbTNF-alpha was comprised with four exons and three introns, and deduced amino acid sequence of its cDNA possessed the TNF family signature, a transmembrane domain, a protease cleavage site, and two cysteine residues, which are the typical characteristics of TNF-alpha gene in mammals and fish. The chemiluminescent (CL) response of rock bream phagocytes was significantly enhanced by pre-incubation with recombinant rbTNF-alpha, when opsonized zymosan was used as a stimulant of the respiratory burst. However, CL enhancing effect of the recombinant rbTNF-alpha was very weak when the respiratory burst activity of phagocytes was triggered with phorbol-12-myristate-13-acetate (PMA) instead of zymosan. These results suggest that rock bream TNF-alpha might have an ability to prime the respiratory burst activity of phagocytes against receptor-mediated phagocytosis inducing stimulants, such as zymosan, but have little ability against stimulants not accompanying receptor-mediated phagocytosis.

Phagocyte-Myocyte Interactions and Consequences during Hypoxic Wound Healing

PubMed Central

Zhang, Shuang; Dehn, Shirley; DeBerge, Matthew; Rhee, KJ; Hudson, Barry; Thorp, Edward

2014-01-01

Myocardial infarction (MI), secondary to atherosclerotic plaque rupture and occlusive thrombi, triggers acute margination of inflammatory neutrophils and monocyte phagocyte subsets to the damaged heart, the latter of which may give rise briefly to differentiated macrophage-like or dendritic-like cells. Within the injured myocardium, a primary function of these phagocytic cells is to remove damaged extracellular matrix, necrotic and apoptotic cardiac cells, as well as immune cells that turn over. Recognition of dying cellular targets by phagocytes triggers intracellular signaling, particularly in macrophages, wherein cytokines and lipid mediators are generated to promote inflammation resolution, fibrotic scarring, angiogenesis, and compensatory organ remodeling. These actions cooperate in an effort to preserve myocardial contractility and prevent heart failure. Immune cell function is modulated by local tissue factors that include secreted protease activity, oxidative stress during clinical reperfusion, and hypoxia. Importantly, experimental evidence suggests that monocyte function and phagocytosis efficiency is compromised in the setting of MI risk factors, including hyperlipidemia and ageing, however underlying mechanisms remain unclear. Herein we review seminal phagocyte and cardiac molecular factors that lead to, and culminate in, the recognition and removal of dying injured myocardium, the effects of hypoxia, and their relationship to cardiac infarct size and heart healing. PMID:24862542

Do not let death do us part: 'find-me' signals in communication between dying cells and the phagocytes.

PubMed

Medina, C B; Ravichandran, K S

2016-06-01

The turnover and clearance of cells is an essential process that is part of many physiological and pathological processes. Improper or deficient clearance of apoptotic cells can lead to excessive inflammation and autoimmune disease. The steps involved in cell clearance include: migration of the phagocyte toward the proximity of the dying cells, specific recognition and internalization of the dying cell, and degradation of the corpse. The ability of phagocytes to recognize and react to dying cells to perform efficient and immunologically silent engulfment has been well-characterized in vitro and in vivo. However, how apoptotic cells themselves initiate the corpse removal and also influence the cells within the neighboring environment during clearance was less understood. Recent exciting observations suggest that apoptotic cells can attract phagocytes through the regulated release of 'find-me' signals. More recent studies also suggest that these find-me signals can have additional roles outside of phagocyte attraction to help orchestrate engulfment. This review will discuss our current understanding of the different find-me signals released by apoptotic cells, how they may be relevant in vivo, and their additional roles in facilitating engulfment.

Do not let death do us part: ‘find-me' signals in communication between dying cells and the phagocytes

PubMed Central

Medina, C B; Ravichandran, K S

2016-01-01

The turnover and clearance of cells is an essential process that is part of many physiological and pathological processes. Improper or deficient clearance of apoptotic cells can lead to excessive inflammation and autoimmune disease. The steps involved in cell clearance include: migration of the phagocyte toward the proximity of the dying cells, specific recognition and internalization of the dying cell, and degradation of the corpse. The ability of phagocytes to recognize and react to dying cells to perform efficient and immunologically silent engulfment has been well-characterized in vitro and in vivo. However, how apoptotic cells themselves initiate the corpse removal and also influence the cells within the neighboring environment during clearance was less understood. Recent exciting observations suggest that apoptotic cells can attract phagocytes through the regulated release of ‘find-me' signals. More recent studies also suggest that these find-me signals can have additional roles outside of phagocyte attraction to help orchestrate engulfment. This review will discuss our current understanding of the different find-me signals released by apoptotic cells, how they may be relevant in vivo, and their additional roles in facilitating engulfment. PMID:26891690

Macrophage Efferocytosis and Prostate Cancer Bone Metastasis

DTIC Science & Technology

2016-10-01

mediator of prostate cancer tumor growth. Specifically, phagocytic macrophages and efferocytosis were found to be upregulated in the blood of...patients with metastatic prostate cancer. Moreover, inhibiting phagocytic macrophages with the chemotherapeutic trabectedin reduced efferocytosis and

Bactericidal Activity and Postantibiotic Effect of Levofloxacin against Anaerobes

PubMed Central

Pendland, Susan L.; Diaz-Linares, Mariela; Garey, Kevin W.; Woodward, Jennifer G.; Ryu, Seonyoung; Danziger, Larry H.

1999-01-01

The bactericidal activity and postantibiotic effect (PAE) of levofloxacin against nine anaerobes were determined. Levofloxacin at concentrations of the MIC and twice the MIC was bactericidal at 24 h to five of nine and nine of nine strains, respectively. The PAE of levofloxacin following a 2-h exposure ranged from 0.06 to 2.88 h. PMID:10508042

THE BACTERICIDAL ACTIVITY OF NORMAL GUINEA PIG SERUM AGAINST LISTERIA MONOCYTOGENES AND ITS INHIBITION BY A LISTERIAL CELL EXTRACT,

DTIC Science & Technology

Normal guinea pig serum contains bactericidins active against Listeria monocytogenes. The listeriocidal activity of the serum did not increase after...factor. Lysozyme was not implicated in the bactericidal system. It was suggested that the bactericidal activity of guinea pig serum might be due either to

Supraependymal cells of hypothalamic third ventricle: identification as resident phagocytes of the brain.

PubMed

Bleier, R; Albrecht, R; Cruce, J A

1975-07-25

Cells lying on the ventricular surface of the hypothalamic ependyma of the tegu lizard exhibit the pseudopodial and flaplike processes characteristic of macrophages found elsewhere. Since they ingest latex beads, they may be considered a resident phagocytic system of the brain. The importance of ependyma and ventricular phagocytes as a first line of defense against viral invasion of the brain, as well as their role in the pathogenesis of certain virus-related diseases, is suggested by a number of experimental and clinical observations.

Evaluation of bactericidal efficacy of silver ions on Escherichia coli for drinking water disinfection.

PubMed

Pathak, Satya P; Gopal, K

2012-07-01

The purpose of this study is the development of a suitable process for the disinfection of drinking water by evaluating bactericidal efficacy of silver ions from silver electrodes. A prototype of a silver ioniser with silver electrodes and control unit has been fabricated. Silver ions from silver electrodes in water samples were estimated with an atomic absorption spectrophotometer. A fresh culture of Escherichia coli (1.75 × 10(3) c.f.u./ml) was exposed to 1, 2, 5, 10 and 20 ppb of silver ions in 100 ml of autoclaved tap water for 60 min. The effect of different pH and temperatures on bactericidal efficacy was observed at constant silver ion concentration (5 ppb) and contact time of 30 min. The maximum bactericidal activity (100%) was observed at 20 ppb of silver ion concentration indicating total disinfection after 20 min while minimum bactericidal activity (25%) was observed after 10 min at 01 ppb of silver ions. Likewise, 100% bactericidal activity was noticed with 2, 5 and 10 ppb of silver ions after 60, 50 and 40 min, respectively. Bactericidal activity at pH 5, 6, 7, 8 and 9 was observed at 79.9%, 79.8%, 80.5%, 100% and 100%, respectively, whereas it was 80.4%, 88.3%, 100%, 100% and 100% at 10°C, 20°C, 30°C, 40°C and 50°C, respectively. The findings of this study revealed that very low concentrations of silver ions at pH 8-9 and temperature >20°C have bactericidal efficacy for total disinfection of drinking water. Silver ionisation is suitable for water disinfection and an appropriate alternative to chlorination which forms carcinogenic disinfection by-products.

Fosfomycin: Uses and potentialities in veterinary medicine

PubMed Central

Pérez, D.S.; Tapia, M.O.; Soraci, A.L.

2014-01-01

Fosfomycin (FOS) is a natural bactericidal broad-spectrum antibiotic which acts on proliferating bacteria by inhibiting cell wall and early murein/peptidoglycan synthesis. Bactericidal activity is evident against Gram positive and Gram negative bacteria and can also act synergistically with other antibiotics. Bacterial resistance to FOS may be natural or acquired. Other properties of this drug include inhibition of bacterial adhesion to epithelial cells, exopolysaccharide biofilm penetration, immunomodulatory effect, phagocytosis promotion and protection against the nephrotoxicity caused by other drugs. FOS has chemical characteristics not typically observed in organic phosphoric compounds and its molecular weight is almost the lowest of all the antimicrobials. It tends to form salts easily due to its acidic nature (disodium salt, for intravenous (IV), intramuscular (IM) and subcutaneous (SC) administration; calcium and trometamol salt: for oral (PO) administration). FOS has a very low protein binding (<0.5%) which, along with its low molecular weight and water solubility, contributes to its good diffusion into fluids (cerebrospinal fluid, aqueous and vitreous humor, interstitial fluid) and tissues (placenta, bone, muscle, liver, kidney and skin/fat). In all species, important differences in the bioavailability have been found after administration in relation to the various derivatives of FOS salts. Pharmacokinetic profiles have been described in humans, chickens, rabbits, cows, dogs, horses and weaning piglets. The low toxicity and potential efficacy of FOS are the main factors that contribute to its use in humans and animals. Thus, it has been used to treat a broad variety of bacterial infections in humans, such as localized peritonitis, brain abscesses, severe soft tissue infections, cystitis and other conditions. In veterinary medicine, FOS is used to treat infectious diseases of broiler chickens and pigs. In broilers, it is administered for the treatment of E. coli and Salmonella spp. infections. In piglets, the drug is prescribed to treat a wide variety of bacterial infections. FOS penetration is demonstrated in phagocytic, respiratory (HEP-2) and intestinal (IPEC-J2) cells. Although not widely used in animals, the drug has shown good results in human medicine. The potentialities of FOS suggest that this drug is a promising candidate for the treatment of infections in veterinary medicine. For these reasons, the aim of this work is to provide animal health practitioners with information on a drug that is not extensively recognized. PMID:26623336

Subtle Variations in Surface Properties of Black Silicon Surfaces Influence the Degree of Bactericidal Efficiency

NASA Astrophysics Data System (ADS)

Bhadra, Chris M.; Werner, Marco; Baulin, Vladimir A.; Truong Khanh, Vi; Kobaisi, Mohammad Al; Nguyen, Song Ha; Balcytis, Armandas; Juodkazis, Saulius; Wang, James Y.; Mainwaring, David E.; Crawford, Russell J.; Ivanova, Elena P.

2018-06-01

One of the major challenges faced by the biomedical industry is the development of robust synthetic surfaces that can resist bacterial colonization. Much inspiration has been drawn recently from naturally occurring mechano-bactericidal surfaces such as the wings of cicada ( Psaltoda claripennis) and dragonfly ( Diplacodes bipunctata) species in fabricating their synthetic analogs. However, the bactericidal activity of nanostructured surfaces is observed in a particular range of parameters reflecting the geometry of nanostructures and surface wettability. Here, several of the nanometer-scale characteristics of black silicon (bSi) surfaces including the density and height of the nanopillars that have the potential to influence the bactericidal efficiency of these nanostructured surfaces have been investigated. The results provide important evidence that minor variations in the nanoarchitecture of substrata can substantially alter their performance as bactericidal surfaces.[Figure not available: see fulltext.

A pharmacologic study on the mechanism of action of Kakkon-to: body temperature elevation and phagocytic activation of macrophages in dogs.

PubMed

Muraoka, Kenichi; Yoshida, Satoshi; Hasegawa, Kazumasa; Nakanishi, Nobuo; Fukuzawa, Isao; Tomita, Akio; Cyong, Jong Chol

2004-10-01

The phagocytic activity of macrophages as a novel approach to scientific elucidation of the effects of Chinese medicines was studied through administration of a kampo preparation, by measuring the rise in body temperature, which is thought to stimulate innate defensive functions of organisms and enhance the immune systems. Using dogs as experimental models, a rise in body temperature following administration of Kakkon-to was observed, and the average number and average rate of phagocytosis of macrophages in blood using latex micro-particles was investigated. The body temperature of the treated animals significantly increased 30 minutes after administration (p<0.01), and remained elevated for more than 5 hours. A comparison of body temperatures before and after administration showed significant increases over controls from 1 to 11 hours, p<0.01; and at 12 hours, p<0.05 after administration. The average number and the average rate of phagocytosis were significantly increased 1 (p<0.05) and 2 (p<0.01) hours after administration. The mean number of phagocytized cells significantly increased (p<0.05) at 1 hour after administration compared with that before administration, and the mean phagocytic rate also increased significantly (p<0.01) 2 hours after administration. Increases (p<0.01) in both the rate of phagocytosis and the number of cells phagocytized were found at every measurement point from 2 to 24 hours after administration. Significant increases (p<0.01) were also observed in both the rate of phagocytosis and the number of cells phagocytized 3 hours after administration, when compared with the control group. This paper demonstrates that ingestion of Kakkon-to not only increases the body temperature but also enhances the phagocytic activity of macrophages, an in vivo defense mechanism, suggesting that Kakkon-to contributes to the suppression of multiplication of common cold viruses and influenza viruses, which consequently results in improvement of various symptoms during infection with common cold viruses.

Could a B-1 cell derived phagocyte "be one" of the peritoneal macrophages during LPS-driven inflammation?

PubMed

Popi, Ana Flavia; Osugui, Lika; Perez, Katia Regina; Longo-Maugéri, Ieda Maria; Mariano, Mario

2012-01-01

The inflammatory response is driven by signals that recruit and elicit immune cells to areas of tissue damage or infection. The concept of a mononuclear phagocyte system postulates that monocytes circulating in the bloodstream are recruited to inflamed tissues where they give rise to macrophages. A recent publication demonstrated that the large increase in the macrophages observed during infection was the result of the multiplication of these cells rather than the recruitment of blood monocytes. We demonstrated previously that B-1 cells undergo differentiation to acquire a mononuclear phagocyte phenotype in vitro (B-1CDP), and we propose that B-1 cells could be an alternative origin for peritoneal macrophages. A number of recent studies that describe the phagocytic and microbicidal activity of B-1 cells in vitro and in vivo support this hypothesis. Based on these findings, we further investigated the differentiation of B-1 cells into phagocytes in vivo in response to LPS-induced inflammation. Therefore, we investigated the role of B-1 cells in the composition of the peritoneal macrophage population after LPS stimulation using osteopetrotic mice, BALB/Xid mice and the depletion of monocytes/macrophages by clodronate treatment. We show that peritoneal macrophages appear in op/op((-/-)) mice after LPS stimulation and exhibit the same Ig gene rearrangement (VH11) that is often found in B-1 cells. These results strongly suggest that op/op((-/-)) peritoneal "macrophages" are B-1CDP. Similarly, the LPS-induced increase in the macrophage population was observed even following monocyte/macrophage depletion by clodronate. After monocyte/macrophage depletion by clodronate, LPS-elicited macrophages were observed in BALB/Xid mice only following the transfer of B-1 cells. Based on these data, we confirmed that B-1 cell differentiation into phagocytes also occurs in vivo. In conclusion, the results strongly suggest that B-1 cell derived phagocytes are a component of the LPS-elicited peritoneal macrophage population.

Different tissue phagocytes sample apoptotic cells to direct distinct homeostasis programs

PubMed Central

Cummings, Ryan J.; Barbet, Gaetan; Bongers, Gerold; Hartmann, Boris M.; Gettler, Kyle; Muniz, Luciana; Furtado, Glaucia C.; Cho, Judy; Lira, Sergio A.; Blander, J. Magarian

2017-01-01

Recognition and removal of apoptotic cells by professional phagocytes, including dendritic cells and macrophages, preserves immune self-tolerance and prevents chronic inflammation and autoimmune pathologies1,2. The diverse array of phagocytes that reside within different tissues, combined with the necessarily prompt nature of apoptotic cell clearance, makes it difficult to study this process in situ. The full spectrum of functions executed by tissue-resident phagocytes in response to homeostatic apoptosis, therefore, remains unclear. Here we show that mouse apoptotic intestinal epithelial cells (IECs), which undergo continuous renewal to maintain optimal barrier and absorptive functions3, are not merely extruded to maintain homeostatic cell numbers4, but are also sampled by a single subset of dendritic cells and two macrophage subsets within a well-characterized network of phagocytes in the small intestinal lamina propria5,6. Characterization of the transcriptome within each subset before and after in situ sampling of apoptotic IECs revealed gene expression signatures unique to each phagocyte, including macrophage-specific lipid metabolism and amino acid catabolism, and a dendritic-cell-specific program of regulatory CD4+ T-cell activation. A common ‘suppression of inflammation’ signature was noted, although the specific genes and pathways involved varied amongst dendritic cells and macrophages, reflecting specialized functions. Apoptotic IECs were trafficked to mesenteric lymph nodes exclusively by the dendritic cell subset and served as critical determinants for the induction of tolerogenic regulatory CD4+ T-cell differentiation. Several of the genes that were differentially expressed by phagocytes bearing apoptotic IECs overlapped with susceptibility genes for inflammatory bowel disease7. Collectively, these findings provide new insights into the consequences of apoptotic cell sampling, advance our understanding of how homeostasis is maintained within the mucosa and set the stage for development of novel therapeutics to alleviate chronic inflammatory diseases such as inflammatory bowel disease. PMID:27828940

Nanoparticles of barium induce apoptosis in human phagocytes

PubMed Central

Mores, Luana; França, Eduardo Luzia; Silva, Núbia Andrade; Suchara, Eliane Aparecida; Honorio-França, Adenilda Cristina

2015-01-01

Purpose Nutrients and immunological factors of breast milk are essential for newborn growth and the development of their immune system, but this secretion can contain organic and inorganic toxins such as barium. Colostrum contamination with barium is an important issue to investigate because this naturally occurring element is also associated with human activity and industrial pollution. The study evaluated the administration of barium nanoparticles to colostrum, assessing the viability and functional activity of colostral mononuclear phagocytes. Methods Colostrum was collected from 24 clinically healthy women (aged 18–35 years). Cell viability, superoxide release, intracellular Ca2+ release, and phagocyte apoptosis were analyzed in the samples. Results Treatment with barium lowered mononuclear phagocyte viability, increased superoxide release, and reduced intracellular calcium release. In addition, barium increased cell death by apoptosis. Conclusion These data suggest that nanoparticles of barium in colostrum are toxic to cells, showing the importance of avoiding exposure to this element. PMID:26451108

Integrins and small GTPases as modulators of phagocytosis.

PubMed

Sayedyahossein, Samar; Dagnino, Lina

2013-01-01

Phagocytosis is the mechanism whereby cells engulf large particles. This process has long been recognized as a critical component of the innate immune response, which constitutes the organism's defense against microorganisms. In addition, phagocytic internalization of apoptotic cells or cell fragments plays important roles in tissue homeostasis and remodeling. Phagocytosis requires target interactions with receptors on the plasma membrane of the phagocytic cell. Integrins have been identified as important mediators of particle clearance, in addition to their well-established roles in cell adhesion, migration and mechanotransduction. Indeed, these ubiquitously expressed proteins impart phagocytic capacity to epithelial, endothelial and mesenchymal cell types. The importance of integrins in particle internalization is emphasized by the ability of microbial and viral pathogens to exploit their signaling pathways to invade host cells, and by the wide variety of disorders that arise from abnormalities in integrin-dependent phagocytic uptake. Copyright © 2013 Elsevier Inc. All rights reserved.

Interactions of phagocytes with the Lyme disease spirochete: role of the Fc receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benach, J.L.; Fleit, H.B.; Habicht, G.S.

1984-10-01

The phagocytic capacity of murine and human mononuclear and polymorphonuclear phagocytes (including peripheral blood monocytes and neutrophils), rabbit and murine peritoneal exudate cells, and the murine macrophage cell line P388D1 against the Lyme disease spirochete was studied. All of these cells were capable of phagocytosing the spirochete; phagocytosis was measured by the uptake of radiolabeled spirochetes, the appearance of immunofluorescent bodies in phagocytic cells, and electron microscopy. Both opsonized and nonopsonized organisms were phagocytosed. The uptake of opsonized organisms by neutrophils was blocked by a monoclonal antibody specific for the Fc receptor and by immune complexes; these findings suggested thatmore » most phagocytosis is mediated by the Fc receptor. Similarly, the uptake of opsonized organisms by human monocytes was inhibited by human monomeric IgG1 and by immune complexes. These results illustrate the role of immune phagocytosis of spirochetes in host defense against Lyme disease.« less

The Role of Phagocytes and NETs in Dermatophytosis.

PubMed

Yoshikawa, Fábio Seiti Yamada; De Almeida, Sandro Rogério

2017-02-01

Innate immunity is the host first line of defense against pathogens. However, only in recent years, we are beginning to better understand the ways it operates. A key player is this branch of the immune response that are the phagocytes, as macrophages, dendritic cells and neutrophils. These cells act as sentinels, employing specialized receptors in the sensing of invaders and host injury, and readily responding to them by production of inflammatory mediators. They afford protection not only by ingesting and destroying pathogens, but also by providing a suitable biochemical environment that shapes the adaptive response. In this review, we aim to present a broad perspective about the role of phagocytes in dermatophytosis, focusing on the mechanisms possibly involved in protective and non-protective responses. A full understanding of how phagocytes fit in the pathogenesis of these infections may open the venue for the development of new and more effective therapeutic approaches.

Nanoparticles of barium induce apoptosis in human phagocytes.

PubMed

Mores, Luana; França, Eduardo Luzia; Silva, Núbia Andrade; Suchara, Eliane Aparecida; Honorio-França, Adenilda Cristina

2015-01-01

Nutrients and immunological factors of breast milk are essential for newborn growth and the development of their immune system, but this secretion can contain organic and inorganic toxins such as barium. Colostrum contamination with barium is an important issue to investigate because this naturally occurring element is also associated with human activity and industrial pollution. The study evaluated the administration of barium nanoparticles to colostrum, assessing the viability and functional activity of colostral mononuclear phagocytes. Colostrum was collected from 24 clinically healthy women (aged 18-35 years). Cell viability, superoxide release, intracellular Ca(2+) release, and phagocyte apoptosis were analyzed in the samples. Treatment with barium lowered mononuclear phagocyte viability, increased superoxide release, and reduced intracellular calcium release. In addition, barium increased cell death by apoptosis. These data suggest that nanoparticles of barium in colostrum are toxic to cells, showing the importance of avoiding exposure to this element.

Quantitative Profiling of Protein S-Glutathionylation Reveals Redox-Dependent Regulation of Macrophage Function During Nanoparticle-Induced Oxidative Stress

DOE PAGES

Duan, Jicheng; Kodali, Vamsi K.; Gaffrey, Matthew J.; ...

2015-12-23

Engineered nanoparticles (ENPs) are emerging functional materials increasingly utilized for commercial and medical applications. Due to the potential hazard effects of ENPs to human health, it is significant to assess and understand the underlying mechanisms of nanotoxicity. Here, we investigate protein S-glutathionylation (SSG) as an underlying regulatory mechanism for ENP-induced oxidative stress in macrophages by applying a recently developed quantitative redox proteomics approach for site-specific measurements of SSG. Three high-volume production ENPs (SiO 2, Fe 3O 4 and CoO) were selected as representative ENPs with low, moderate, and high reactive oxygen species (ROS) activity, respectively. Among these nanoparticles, we observemore » that CoO led to the most significant dose-dependent oxidative stress and increase of protein SSG modifications in macrophages. Our site-specific SSG changes highlighted a broad set of redox sensitive proteins and their specific Cys residues potentially implicated in stress response. Functional analysis revealed that the most significantly enriched functional categories for SSG-modified proteins were stress response, cellular structure change, and cell death or survival. Moreover, ENPs-induce oxidative stress levels (CoO > Fe 3O 4 > SiO 2) were found to correlate well with the levels of impairment of macrophage phagocytic activity and the overall degrees of increases in SSG. RNA silencing knockdown experiment of glutaredoxin 1 (Grx1) also led to a decreased phagocytic activity in macrophages, which suggested a regulatory role of SSG in phagocytosis. Together, the results provided valuable insights of protein SSG as a potential regulatory mechanism in response to nanomaterial-induced oxidative stress and immunity dysfunction.« less

Quantitative Profiling of Protein S-Glutathionylation Reveals Redox-Dependent Regulation of Macrophage Function During Nanoparticle-Induced Oxidative Stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duan, Jicheng; Kodali, Vamsi K.; Gaffrey, Matthew J.

Engineered nanoparticles (ENPs) are emerging functional materials increasingly utilized for commercial and medical applications. Due to the potential hazard effects of ENPs to human health, it is significant to assess and understand the underlying mechanisms of nanotoxicity. Here, we investigate protein S-glutathionylation (SSG) as an underlying regulatory mechanism for ENP-induced oxidative stress in macrophages by applying a recently developed quantitative redox proteomics approach for site-specific measurements of SSG. Three high-volume production ENPs (SiO 2, Fe 3O 4 and CoO) were selected as representative ENPs with low, moderate, and high reactive oxygen species (ROS) activity, respectively. Among these nanoparticles, we observemore » that CoO led to the most significant dose-dependent oxidative stress and increase of protein SSG modifications in macrophages. Our site-specific SSG changes highlighted a broad set of redox sensitive proteins and their specific Cys residues potentially implicated in stress response. Functional analysis revealed that the most significantly enriched functional categories for SSG-modified proteins were stress response, cellular structure change, and cell death or survival. Moreover, ENPs-induce oxidative stress levels (CoO > Fe 3O 4 > SiO 2) were found to correlate well with the levels of impairment of macrophage phagocytic activity and the overall degrees of increases in SSG. RNA silencing knockdown experiment of glutaredoxin 1 (Grx1) also led to a decreased phagocytic activity in macrophages, which suggested a regulatory role of SSG in phagocytosis. Together, the results provided valuable insights of protein SSG as a potential regulatory mechanism in response to nanomaterial-induced oxidative stress and immunity dysfunction.« less

Bactericidal activity of biomimetic diamond nanocone surfaces.

PubMed

Fisher, Leanne E; Yang, Yang; Yuen, Muk-Fung; Zhang, Wenjun; Nobbs, Angela H; Su, Bo

2016-03-17

The formation of biofilms on implant surfaces and the subsequent development of medical device-associated infections are difficult to resolve and can cause considerable morbidity to the patient. Over the past decade, there has been growing recognition that physical cues, such as surface topography, can regulate biological responses and possess bactericidal activity. In this study, diamond nanocone-patterned surfaces, representing biomimetic analogs of the naturally bactericidal cicada fly wing, were fabricated using microwave plasma chemical vapor deposition, followed by bias-assisted reactive ion etching. Two structurally distinct nanocone surfaces were produced, characterized, and the bactericidal ability examined. The sharp diamond nanocone features were found to have bactericidal capabilities with the surface possessing the more varying cone dimension, nonuniform array, and decreased density, showing enhanced bactericidal ability over the more uniform, highly dense nanocone surface. Future research will focus on using the fabrication process to tailor surface nanotopographies on clinically relevant materials that promote both effective killing of a broader range of microorganisms and the desired mammalian cell response. This study serves to introduce a technology that may launch a new and innovative direction in the design of biomaterials with capacity to reduce the risk of medical device-associated infections.

Following the mechanisms of bacteriostatic versus bactericidal action using Raman spectroscopy.

PubMed

Bernatová, Silvie; Samek, Ota; Pilát, Zdeněk; Serý, Mojmír; Ježek, Jan; Jákl, Petr; Siler, Martin; Krzyžánek, Vladislav; Zemánek, Pavel; Holá, Veronika; Dvořáčková, Milada; Růžička, Filip

2013-10-24

Antibiotics cure infections by influencing bacterial growth or viability. Antibiotics can be divided to two groups on the basis of their effect on microbial cells through two main mechanisms, which are either bactericidal or bacteriostatic. Bactericidal antibiotics kill the bacteria and bacteriostatic antibiotics suppress the growth of bacteria (keep them in the stationary phase of growth). One of many factors to predict a favorable clinical outcome of the potential action of antimicrobial chemicals may be provided using in vitro bactericidal/bacteriostatic data (e.g., minimum inhibitory concentrations-MICs). Consequently, MICs are used in clinical situations mainly to confirm resistance, and to determine the in vitro activities of new antimicrobials. We report on the combination of data obtained from MICs with information on microorganisms' "fingerprint" (e.g., DNA/RNA, and proteins) provided by Raman spectroscopy. Thus, we could follow mechanisms of the bacteriostatic versus bactericidal action simply by detecting the Raman bands corresponding to DNA. The Raman spectra of Staphylococcus epidermidis treated with clindamycin (a bacteriostatic agent) indeed show little effect on DNA which is in contrast with the action of ciprofloxacin (a bactericidal agent), where the Raman spectra show a decrease in strength of the signal assigned to DNA, suggesting DNA fragmentation.

A comparison of bactericidal/permeability-increasing protein variant versus recombinant endotoxin-neutralizing protein for the treatment of Escherichia coli sepsis in rats .

PubMed

Stack, A M; Saladino, R A; Siber, G R; Thompson, C; Marra, M N; Novitsky, T J; Fleisher, G R

1997-01-01

To compare a recombinant bactericidal/permeability-increasing protein variant and a recombinant endotoxin-neutralizing protein. Randomized, blinded, controlled study, using a rat model of sepsis. Animal research facility. Male Wistar rats. An inoculum of 1.5 x 10(7) to 1.8 x 10(8) Escherichia coli O18ac K1, implanted in the peritoneum, produced bacteremia in 95% of animals after 1 hr. One hour after E. coli challenge, animals received recombinant bactericidal/permeability-increasing protein variant, recombinant endotoxin-neutralizing protein, or saline intravenously, followed by ceftriaxone and gentamicin intramuscularly. Twenty-four (85.7%) of 28 animals receiving recombinant endotoxin-neutralizing protein (p < .001 vs. control) survived 7 days compared with nine (33.3%) of 27 recombinant bactericidal/permeability-increasing protein variant-treated (p < .001 vs. control) and two (6.5%) of 31 control animals. Both recombinant endotoxin-neutralizing protein and recombinant bactericidal/permeability-increasing protein variant improved survival. Recombinant endotoxin-neutralizing protein was superior to recombinant bactericidal/permeability-increasing protein variant in its protective effect at the doses tested. Our results suggest that both proteins may be useful in the treatment of human Gram-negative sepsis.

Marek's disease virus infection of phagocytes: a de novo in vitro infection model.

PubMed

Chakraborty, Pankaj; Vervelde, Lonneke; Dalziel, Robert G; Wasson, Peter S; Nair, Venugopal; Dutia, Bernadette M; Kaiser, Pete

2017-05-01

Marek's disease virus (MDV) is an alphaherpesvirus that induces T-cell lymphomas in chickens. Natural infections in vivo are caused by the inhalation of infected poultry house dust and it is presumed that MDV infection is initiated in the macrophages from where the infection is passed to B cells and activated T cells. Virus can be detected in B and T cells and macrophages in vivo, and both B and T cells can be infected in vitro. However, attempts to infect macrophages in vitro have not been successful. The aim of this study was to develop a model for infecting phagocytes [macrophages and dendritic cells (DCs)] with MDV in vitro and to characterize the infected cells. Chicken bone marrow cells were cultured with chicken CSF-1 or chicken IL-4 and chicken CSF-2 for 4 days to produce macrophages and DCs, respectively, and then co-cultured with FACS-sorted chicken embryo fibroblasts (CEFs) infected with recombinant MDV expressing EGFP. Infected phagocytes were identified and sorted by FACS using EGFP expression and phagocyte-specific mAbs. Detection of MDV-specific transcripts of ICP4 (immediate early), pp38 (early), gB (late) and Meq by RT-PCR provided evidence for MDV replication in the infected phagocytes. Time-lapse confocal microscopy was also used to demonstrate MDV spread in these cells. Subsequent co-culture of infected macrophages with CEFs suggests that productive virus infection may occur in these cell types. This is the first report of in vitro infection of phagocytic cells by MDV.

Wright-Giemsa staining to observe phagocytes in Locusta migratoria infected with Metarhizium acridum.

PubMed

Yu, Ying; Cao, Yueqing; Xia, Yuxian; Liu, Feihong

2016-09-01

Hemocytes are the first line of defense in the invertebrate immune system. Understanding their roles in cellular immunity is important for developing more efficient mycoinsecticides. However, the exact classification of hemocytes has been inconsistent and the various types of phagocytes in Locusta migratoria are poorly defined. Herein, the Wright-Giemsa staining method and microscopy were employed to characterize the hemocytes of L. migratoria following infection by Metarhizium acridum. Hemocytes were classified into four types, including granulocytes, plasmatocytes, prohemocytes, and oenocytoids, based on size, morphology, and dye-staining properties. Each type of hemocyte was classified into several subtypes according to different ultrastructural features. At least four subtypes of granulocytes or plasmatocytes, including small-nucleus plasmatocytes, basophil vacuolated plasmatocytes, homogeneous plasmatocytes, and eosinophilic granulocytes, carried out phagocytosis. The percentage of total phagocytes increased two days after infection by M. acridum, then gradually declined during the next two days, and then increased sharply again at the fifth day. Our data suggested that plasmatocytes and granulocytes may be the major phagocytes that protect against invasion by a fungal pathogen in L. migratoria. Total hemocytes in locusts significantly increased in the initial days after infection and decreased in the late period of infection compared to controls. In the hemocoel, hyphal bodies were recognized, enwrapped, and digested by the phagocytes. Then, the broken hyphal pieces were packaged as vesicles to be secreted from the cell. Moreover, locusts might have a sensitive and efficient cellular immune system that can regulate phagocyte differentiation and proliferation before fungi colonize the host hemolymph. Copyright © 2016 Elsevier Inc. All rights reserved.

Anesthetic propofol overdose causes endothelial cytotoxicity in vitro and endothelial barrier dysfunction in vivo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Ming-Chung; Department of Anesthesiology, Chi Mei Medical Center, Liouying, Tainan, Taiwan; Chen, Chia-Ling

An overdose and a prolonged treatment of propofol may cause cellular cytotoxicity in multiple organs and tissues such as brain, heart, kidney, skeletal muscle, and immune cells; however, the underlying mechanism remains undocumented, particularly in vascular endothelial cells. Our previous studies showed that the activation of glycogen synthase kinase (GSK)-3 is pro-apoptotic in phagocytes during overdose of propofol treatment. Regarding the intravascular administration of propofol, we therefore hypothesized that propofol overdose also induces endothelial cytotoxicity via GSK-3. Propofol overdose (100 μg/ml) inhibited growth in human arterial and microvascular endothelial cells. After treatment, most of the endothelial cells experienced caspase-independent necrosis-likemore » cell death. The activation of cathepsin D following lysosomal membrane permeabilization (LMP) determined necrosis-like cell death. Furthermore, propofol overdose also induced caspase-dependent apoptosis, at least in part. Caspase-3 was activated and acted downstream of mitochondrial transmembrane potential (MTP) loss; however, lysosomal cathepsins were not required for endothelial cell apoptosis. Notably, activation of GSK-3 was essential for propofol overdose-induced mitochondrial damage and apoptosis, but not necrosis-like cell death. Intraperitoneal administration of a propofol overdose in BALB/c mice caused an increase in peritoneal vascular permeability. These results demonstrate the cytotoxic effects of propofol overdose, including cathepsin D-regulated necrosis-like cell death and GSK-3-regulated mitochondrial apoptosis, on endothelial cells in vitro and the endothelial barrier dysfunction by propofol in vivo. Highlights: ► Propofol overdose causes apoptosis and necrosis in endothelial cells. ► Propofol overdose triggers lysosomal dysfunction independent of autophagy. ► Glycogen synthase kinase-3 facilitates propofol overdose-induced apoptosis. ► Propofol overdose causes an increase in peritoneal vascular permeability.« less

Recruitment of 99m-technetium- or 111-indium-labelled polymorphonuclear leucocytes in experimentally induced pyogranulomas in lambs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guilloteau, L.; Pepin, M.; Pardon, P.

1990-10-01

The recruitment of polymorphonuclear leucocytes (PMNs) during the development of experimental pyogranulomas induced by Corynebacterium pseudotuberculosis was followed in nine male lambs by scintigraphic examination. Autologous blood PMNs were labelled with 99m-technetium or 111-indium and were re-injected intravenously into infected lambs. The functional properties of the labelled cells were monitored (1) in vitro by measuring their phagocytic and bactericidal activity against C. pseudotuberculosis and their chemotaxis under agarose, and (2) in vivo by following scintigraphically their capacity to accumulate in an inflammatory focus induced by intradermal injection of latex beads coated with Salmonella abortus equi lipopolysaccharide. Following inoculation of corynebacteriamore » into the right ear of lambs, radioactive foci were observed to be localized in the right ear and in the draining lymph nodes during the 4 days following inoculation. Histopathological examination performed 32 h after inoculation confirmed the intense accumulation of PMNs at these sites. With the exception of one animal, which presented visible foci in the neck 14 days postinoculation, no radioactive foci were observed during the later phases of experimental infection, despite the presence of multiple pyogranulomas which were confirmed by bacteriological examination after necropsy of the lambs. Histopathological examination of these lesions revealed layers of fibroblasts, lymphocytes, and macrophages surrounding a necrotic centre. The results of these studies suggest that the contribution of PMNs during the chronic phase of inflammation is considerably reduced in comparison with the acute inflammatory phase of the infectious process.« less

Antiorthostatic suspension stimulates profiles of macrophage activation in mice

NASA Technical Reports Server (NTRS)

Miller, E. S.; Bates, R. A.; Koebel, D. A.; Sonnenfeld, G.

1999-01-01

The antiorthostatic suspension model simulates certain physiological effects of spaceflight. We have previously reported BDF1 mice suspended by the tail in the antiorthostatic orientation for 4 days express high levels of resistance to virulent Listeria monocytogenesinfection. In the present study, we examined whether the increased resistance to this organism correlates with profiles of macrophage activation, given the role of the macrophage in killing this pathogen in vivo. We infected BDF1 mice with a lethal dose of virulent L. monocytogenes on day 4 of antiorthostatic suspension and 24 h later constructed profiles of macrophage activation. Viable listeria could not be detected in mice suspended in the antiorthostatic orientation 24 h after infection. Flow cytometric analysis revealed the numbers of granulocytes and mononuclear phagocytes in the spleen of infected mice were not significantly altered as a result of antiorthostatic suspension. Splenocytes from antiorthostatically suspended infected mice produced increased titers of IL-1. Serum levels of neopterin, a nucleotide metabolite secreted by activated macrophages, were enhanced in mice infected during antiorthostatic suspension, but not in antiorthostatically suspended naive mice. Splenic macrophages from mice infected on day 4 of suspension produced enhanced levels of lysozyme. In contrast to the results from antiorthostatically suspended infected mice, macrophages from antiorthostatically suspended uninfected mice did not express enhanced bactericidal activities. The collective results indicate that antiorthostatic suspension can stimulate profiles of macrophage activation which correlate with increased resistance to infection by certain classes of pathogenic bacteria.

Gallium Disrupts Iron Metabolism of Mycobacteria Residing within Human Macrophages

PubMed Central

Olakanmi, Oyebode; Britigan, Bradley E.; Schlesinger, Larry S.

2000-01-01

Mycobacterium tuberculosis and M. avium complex (MAC) enter and multiply within monocytes and macrophages in phagosomes. In vitro growth studies using standard culture media indicate that siderophore-mediated iron (Fe) acquisition plays a critical role in the growth and metabolism of both M. tuberculosis and MAC. However, the applicability of such studies to conditions within the macrophage phagosome is unclear, due in part to the absence of experimental means to inhibit such a process. Based on the ability of gallium (Ga3+) to concentrate within mononuclear phagocytes and on evidence that Ga disrupts cellular Fe-dependent metabolic pathways by substituting for Fe3+ and failing to undergo redox cycling, we hypothesized that Ga could disrupt Fe acquisition and Fe-dependent metabolic pathways of mycobacteria. We find that Ga(NO3)3 and Ga-transferrin produce an Fe-reversible concentration-dependent growth inhibition of M. tuberculosis strains and MAC grown extracellularly and within human macrophages. Ga is bactericidal for M. tuberculosis growing extracellularly and within macrophages. Finally, we provide evidence that exogenously added Fe is acquired by intraphagosomal M. tuberculosis and that Ga inhibits this Fe acquisition. Thus, Ga(NO3)3 disruption of mycobacterial Fe metabolism may serve as an experimental means to study the mechanism of Fe acquisition by intracellular mycobacteria and the role of Fe in intracellular survival. Furthermore, given the inability of biological systems to discriminate between Ga and Fe, this approach could have broad applicability to the study of Fe metabolism of other intracellular pathogens. PMID:10992462

Absence of Proton Channels in COS-7 Cells Expressing Functional NADPH Oxidase Components

PubMed Central

Morgan, Deri; Cherny, Vladimir V.; Price, Marianne O.; Dinauer, Mary C.; DeCoursey, Thomas E.

2002-01-01

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is an enzyme of phagocytes that produces bactericidal superoxide anion (O2 −) via an electrogenic process. Proton efflux compensates for the charge movement across the cell membrane. The proton channel responsible for the H+ efflux was thought to be contained within the gp91phox subunit of NADPH oxidase, but recent data do not support this idea (DeCoursey, T.E., V.V. Cherny, D. Morgan, B.Z. Katz, and M.C. Dinauer. 2001. J. Biol. Chem. 276:36063–36066). In this study, we investigated electrophysiological properties and superoxide production of COS-7 cells transfected with all NADPH oxidase components required for enzyme function (COSphox). The 7D5 antibody, which detects an extracellular epitope of the gp91phox protein, labeled 96–98% of COSphox cells. NADPH oxidase was functional because COSphox (but not COSWT) cells stimulated by phorbol myristate acetate (PMA) or arachidonic acid (AA) produced superoxide anion. No proton currents were detected in either wild-type COS-7 cells (COSWT) or COSphox cells studied at pHo 7.0 and pHi 5.5 or 7.0. Anion currents that decayed at voltages positive to 40 mV were the only currents observed. PMA or AA did not elicit detectable H+ current in COSWT or COSphox cells. Therefore, gp91phox does not function as a proton channel in unstimulated cells or in activated cells with a demonstrably functional oxidase. PMID:12034764

Absence of proton channels in COS-7 cells expressing functional NADPH oxidase components.

PubMed

Morgan, Deri; Cherny, Vladimir V; Price, Marianne O; Dinauer, Mary C; DeCoursey, Thomas E

2002-06-01

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is an enzyme of phagocytes that produces bactericidal superoxide anion (O(2)(-)) via an electrogenic process. Proton efflux compensates for the charge movement across the cell membrane. The proton channel responsible for the H(+) efflux was thought to be contained within the gp91(phox) subunit of NADPH oxidase, but recent data do not support this idea (DeCoursey, T.E., V.V. Cherny, D. Morgan, B.Z. Katz, and M.C. Dinauer. 2001. J. Biol. Chem. 276:36063-36066). In this study, we investigated electrophysiological properties and superoxide production of COS-7 cells transfected with all NADPH oxidase components required for enzyme function (COS(phox)). The 7D5 antibody, which detects an extracellular epitope of the gp91(phox) protein, labeled 96-98% of COS(phox) cells. NADPH oxidase was functional because COS(phox) (but not COS(WT)) cells stimulated by phorbol myristate acetate (PMA) or arachidonic acid (AA) produced superoxide anion. No proton currents were detected in either wild-type COS-7 cells (COS(WT)) or COS(phox) cells studied at pH(o) 7.0 and pH(i) 5.5 or 7.0. Anion currents that decayed at voltages positive to 40 mV were the only currents observed. PMA or AA did not elicit detectable H(+) current in COS(WT) or COS(phox) cells. Therefore, gp91(phox) does not function as a proton channel in unstimulated cells or in activated cells with a demonstrably functional oxidase.

Macrophage P2X4 receptors augment bacterial killing and protect against sepsis

PubMed Central

Csóka, Balázs; Németh, Zoltán H.; Szabó, Ildikó; Davies, Daryl L.; Varga, Zoltán V.; Pálóczi, János; Falzoni, Simonetta; Di Virgilio, Francesco; Muramatsu, Rieko; Pacher, Pál

2018-01-01

The macrophage is a major phagocytic cell type, and its impaired function is a primary cause of immune paralysis, organ injury, and death in sepsis. An incomplete understanding of the endogenous molecules that regulate macrophage bactericidal activity is a major barrier for developing effective therapies for sepsis. Using an in vitro killing assay, we report here that the endogenous purine ATP augments the killing of sepsis-causing bacteria by macrophages through P2X4 receptors (P2X4Rs). Using newly developed transgenic mice expressing a bioluminescent ATP probe on the cell surface, we found that extracellular ATP levels increase during sepsis, indicating that ATP may contribute to bacterial killing in vivo. Studies with P2X4R-deficient mice subjected to sepsis confirm the role of extracellular ATP acting on P2X4Rs in killing bacteria and protecting against organ injury and death. Results with adoptive transfer of macrophages, myeloid-specific P2X4R-deficient mice, and P2rx4 tdTomato reporter mice indicate that macrophages are essential for the antibacterial, antiinflammatory, and organ protective effects of P2X4Rs in sepsis. Pharmacological targeting of P2X4Rs with the allosteric activator ivermectin protects against bacterial dissemination and mortality in sepsis. We propose that P2X4Rs represent a promising target for drug development to control bacterial growth in sepsis and other infections. PMID:29875325

Robust Phagocyte Recruitment Controls the Opportunistic Fungal Pathogen Mucor circinelloides in Innate Granulomas In Vivo.

PubMed

Inglesfield, Sarah; Jasiulewicz, Aleksandra; Hopwood, Matthew; Tyrrell, James; Youlden, George; Mazon-Moya, Maria; Millington, Owain R; Mostowy, Serge; Jabbari, Sara; Voelz, Kerstin

2018-03-27

Mucormycosis is an emerging fungal infection with extremely high mortality rates in patients with defects in their innate immune response, specifically in functions mediated through phagocytes. However, we currently have a limited understanding of the molecular and cellular interactions between these innate immune effectors and mucormycete spores during the early immune response. Here, the early events of innate immune recruitment in response to infection by Mucor circinelloides spores are modeled by a combined in silico modeling approach and real-time in vivo microscopy. Phagocytes are rapidly recruited to the site of infection in a zebrafish larval model of mucormycosis. This robust early recruitment protects from disease onset in vivo In silico analysis identified that protection is dependent on the number of phagocytes at the infection site, but not the speed of recruitment. The mathematical model highlights the role of proinflammatory signals for phagocyte recruitment and the importance of inhibition of spore germination for protection from active fungal disease. These in silico data are supported by an in vivo lack of fungal spore killing and lack of reactive oxygen burst, which together result in latent fungal infection. During this latent stage of infection, spores are controlled in innate granulomas in vivo Disease can be reactivated by immunosuppression. Together, these data represent the first in vivo real-time analysis of innate granuloma formation during the early stages of a fungal infection. The results highlight a potential latent stage during mucormycosis that should urgently be considered for clinical management of patients. IMPORTANCE Mucormycosis is a dramatic fungal infection frequently leading to the death of patients. We know little about the immune response to the fungus causing this infection, although evidence points toward defects in early immune events after infection. Here, we dissect this early immune response to infectious fungal spores. We show that specialized white blood cells (phagocytes) rapidly respond to these spores and accumulate around the fungus. However, we demonstrate that the mechanisms that enable phagocytes to kill the fungus fail, allowing for survival of spores. Instead a cluster of phagocytes resembling an early granuloma is formed around spores to control the latent infection. This study is the first detailed analysis of early granuloma formation during a fungal infection highlighting a latent stage that needs to be considered for clinical management of patients. Copyright © 2018 Inglesfield et al.

N-acetylcysteine improves redox status, mitochondrial dysfunction, mucin-depleted crypts and epithelial hyperplasia in dextran sulfate sodium-induced oxidative colitis in mice.

PubMed

Amrouche-Mekkioui, Ilhem; Djerdjouri, Bahia

2012-09-15

The effect of N-acetylcysteine (NAC), a pharmacological antioxidant was investigated in a murine model of chronic colitis. Male NMRI mice were given 5% dextran sulfate sodium (DSS) in drinking water for 5 days followed by 10 days of water, three times. Compared to control mice given water, DSS-treated mice displayed severe imbalanced redox status with decreased glutathione and catalase, but increased malondialdehyde, protein carbonyls, nitric oxide and myeloperoxidase levels, at days 35th (active colitis) and 45th (recovery period). It also resulted in mitochondrial dysfunction, mucosal ulcers, mucin-depleted crypts and epithelial cell apoptosis. Crypt abscesses and glandular hyperplasia occurred selectively in distal colon. NAC (150 mg/kg) given in drinking water for 45 days along with 3 DSS cycles improved the hallmarks of DSS-colitis. Interestingly, the moderate impact of NAC on lipids and proteins oxidation correlated with myeloperoxidase and nitric oxide levels.NAC as a mucoregulator and a thiol restoring agent is protective on oxidative crypt alterations, mucin depletion, epithelial cell hyperplasia and apoptosis. Taken together, our results highlight the role of NAC as a scavenger of phagocytes-derived reactive oxygen species in mice DDS-colitis, suggesting that a long term NAC diet might be beneficial in inflammatory bowel diseases and colorectal cancer. Copyright © 2012 Elsevier B.V. All rights reserved.

Myeloperoxidase-derived chlorinating species induce protein carbamylation through decomposition of thiocyanate and urea: Novel pathways generating dysfunctional high-density lipoprotein

PubMed Central

Holzer, Michael; Zangger, Klaus; El-Gamal, Dalia; Binder, Veronika; Curcic, Sanja; Konya, Viktoria; Schuligoi, Rufina; Heinemann, Akos; Marsche, Gunther

2013-01-01

Aim Protein carbamylation through cyanate is thought to have a causal role in promoting cardiovascular disease. We recently observed that the phagocyte protein myeloperoxidase (MPO) specifically induces high-density lipoprotein carbamylation, rather than chlorination, in human atherosclerotic lesions, raising the possibility that MPO-derived chlorinating species are involved in cyanate formation. Results Here we show that MPO-derived chlorinating species rapidly decompose the plasma components thiocyanate and urea thereby promoting (lipo)protein carbamylation. Strikingly, the presence of physiologic concentrations of thiocyanate completely prevented MPO-induced 3-chlorotyrosine formation in HDL. Moreover, thiocyanate scavenged a 2.5-fold molar excess of hypochlorous acid, promoting HDL carbamylation, but not chlorination. Carbamylation of HDL resulted in a loss of anti-inflammatory and anti-oxidative properties. Cyanate significantly impaired (i) HDL’s ability to activate lecithin-cholesterol acyltransferase, (ii) the activity of paraoxonase, a major HDL-associated anti-inflammatory enzyme and (iii) the anti-oxidative activity of HDL. Innovation Here we report that MPO-derived chlorinating species preferentially induce protein carbamylation - rather than chlorination - in the presence of physiologically relevant thiocyanate concentrations. Carbamylation of HDL results in the loss of its anti-inflammatory and anti-oxidative activities. Conclusion MPO-mediated decomposition of thiocyanate and/or urea might be a relevant mechanism for generating dysfunctional HDL in human disease. PMID:22462773

[Bacterial Translocation from Intestine: Microbiological, Immunological and Pathophysiological Aspects].

PubMed

Podoprigora, G I; Kafarskaya, L I; Bainov, N A; Shkoporov, A N

2015-01-01

Bacterial translocation (BT) is both pathology and physiology phenomenon. In healthy newborns it accompanies the process of establishing the autochthonous intestinal microbiota and the host microbiome. In immunodeficiency it can be an aethio-pathogenetic link and a manifestation of infection or septic complications. The host colonization resistance to exogenous microbic colonizers is provided by gastrointestinal microbiota in concert with complex constitutional and adaptive defense mechanisms. BT may be result of barrier dysfunction and self-purification mechanisms involving the host myeloid cell phagocytic system and opsonins. Dynamic cell humoral response to microbial molecular patterns that occurs on the mucous membranes initiates receptorsignalingpathways and cascade ofreactions. Their vector and results are largely determined by cross-reactivity between microbiome and the host genome. Enterocyte barriers interacting with microbiota play leading role in providing adaptive, homeostatic and stress host reactivity. Microcirculatory ischemic tissue alterations and inflammatory reactions increase the intestinal barrier permeability and BT These processes a well as mechanisms for apoptotic cells and bacteria clearance are justified to be of prospective research interest. The inflammatory and related diseases caused by alteration and dysfunction of the intestinal barrier are reasonably considered as diseases of single origin. Maternal microbiota affects theformation of the innate immune system and the microbiota of the newborn, including intestinal commensal translocation during lactation. Deeper understanding of intestinal barrier mechanisms needs complex microbiological, immunological, pathophysiological, etc. investigations using adequate biomodels, including gnotobiotic animals.

Chronic Iron Overload Results in Impaired Bacterial Killing of THP-1 Derived Macrophage through the Inhibition of Lysosomal Acidification

PubMed Central

Kao, Jun-Kai; Wang, Shih-Chung; Ho, Li-Wei; Huang, Shi-Wei; Chang, Shu-Hao; Yang, Rei-Cheng; Ke, Yu-Yuan; Wu, Chun-Ying; Wang, Jiu-Yao; Shieh, Jeng-Jer

2016-01-01

Iron is essential for living organisms and the disturbance of iron homeostasis is associated with altered immune function. Additionally, bacterial infections can cause major complications in instances of chronic iron overload, such as patients with transfusion-dependent thalassemia. Monocytes and macrophages play important roles in maintaining systemic iron homoeostasis and in defense against invading pathogens. However, the effect of iron overload on the function of monocytes and macrophages is unclear. We elucidated the effects of chronic iron overload on human monocytic cell line (THP-1) and THP-1 derived macrophages (TDM) by continuously exposing them to high levels of iron (100 μM) to create I-THP-1 and I-TDM, respectively. Our results show that iron overload did not affect morphology or granularity of I-THP-1, but increased the granularity of I-TDM. Bactericidal assays for non-pathogenic E. coli DH5α, JM109 and pathogenic P. aeruginosa all revealed decreased efficiency with increasing iron concentration in I-TDM. The impaired P. aeruginosa killing ability of human primary monocyte derived macrophages (hMDM) was also found when cells are cultured in iron contained medium. Further studies on the bactericidal activity of I-TDM revealed lysosomal dysfunction associated with the inhibition of lysosomal acidification resulting in increasing lysosomal pH, the impairment of post-translational processing of cathepsins (especially cathepsin D), and decreased autophagic flux. These findings may explain the impaired innate immunity of thalassemic patients with chronic iron overload, suggesting the manipulation of lysosomal function as a novel therapeutic approach. PMID:27244448

Inflammatory Role of Macrophage Xanthine Oxidoreductase in Pulmonary Hypertension: Implications for Novel Therapeutic Approaches

DTIC Science & Technology

2015-10-01

Lung Inflammation, Uric Acid, Chronic Obstructive Pulmonary Disease, Mononuclear Phagocyte , Monosodium Urate, XOR WT, XOR KO, Wistar Kyoto, Pulmonary...0451 Annual Report (Year 1) 4 Mononuclear Phagocyte XOR Activity and Superoxide Generation Were Reduced by

The structure of mononuclear phagocytes differentiating in vivo. III. The effect of particulate foreign substances.

PubMed

Goldner, R D; Adams, D O

1977-11-01

The response of mononuclear phagocytes to three inert particles--barium sulfate, talc, and thorium dioxide--was studied by correlated light and electron microscopy. All three particles induced maturation of the mononuclear phagocytes, which proceeded to the stage of the mature macrophage and required 7 to 9 days. Once established, maturation persisted as long as 45 days, as did the inert particles. The resultant lesions, dense aggregates of mature macrophages, were termed mature granulomas. The resultant maturation differed from that produced by digestible bacteria in tempo and extent but not in pattern.

Phagocyte-myocyte interactions and consequences during hypoxic wound healing.

PubMed

Zhang, Shuang; Dehn, Shirley; DeBerge, Matthew; Rhee, Ki-Jong; Hudson, Barry; Thorp, Edward B

2014-01-01

Myocardial infarction (MI), secondary to atherosclerotic plaque rupture and occlusive thrombi, triggers acute margination of inflammatory neutrophils and monocyte phagocyte subsets to the damaged heart, the latter of which may give rise briefly to differentiated macrophage-like or dendritic-like cells. Within the injured myocardium, a primary function of these phagocytic cells is to remove damaged extracellular matrix, necrotic and apoptotic cardiac cells, as well as immune cells that turn over. Recognition of dying cellular targets by phagocytes triggers intracellular signaling, particularly in macrophages, wherein cytokines and lipid mediators are generated to promote inflammation resolution, fibrotic scarring, angiogenesis, and compensatory organ remodeling. These actions cooperate in an effort to preserve myocardial contractility and prevent heart failure. Immune cell function is modulated by local tissue factors that include secreted protease activity, oxidative stress during clinical reperfusion, and hypoxia. Importantly, experimental evidence suggests that monocyte function and phagocytosis efficiency is compromised in the setting of MI risk factors, including hyperlipidemia and ageing, however underlying mechanisms remain unclear. Herein we review seminal phagocyte and cardiac molecular factors that lead to, and culminate in, the recognition and removal of dying injured myocardium, the effects of hypoxia, and their relationship to cardiac infarct size and heart healing. Copyright © 2014 Elsevier Inc. All rights reserved.

Mononuclear-macrophages but not neutrophils act as major infiltrating anti-leptospiral phagocytes during leptospirosis.

PubMed

Chen, Xu; Li, Shi-Jun; Ojcius, David M; Sun, Ai-Hua; Hu, Wei-Lin; Lin, Xu'ai; Yan, Jie

2017-01-01

To identify the major infiltrating phagocytes during leptospirosis and examine the killing mechanism used by the host to eliminate Leptospira interrogans. Major infiltrating phagocytes in Leptospira-infected C3H/HeJ mice were detected by immunohistochemistry. Chemokines and vascular endothelial cell adhesion molecules (VECAMs) of Leptospira-infected mice and leptospirosis patients were detected by microarray and immunohistochemistry. Leptospira-phagocytosing and -killing abilities of human or mouse macrophages and neutrophils, and the roles of intracellular ROS, NO and [Ca2+]i in Leptospira-killing process were evaluated by confocal microscopy and spectrofluorimetry. Peripheral blood mononuclear-macrophages rather than neutrophils were the main infiltrating phagocytes in the lungs, liver and kidneys of infected mice. Levels of macrophage- but not neutrophil-specific chemokines and VECAMs were significantly increased in the samples from infected mice and patients. All macrophages tested had a higher ability than neutrophils to phagocytose and kill leptospires. Higher ROS and NO levels and [Ca2+]i in the macrophages were involved in killing leptospires. Human macrophages displayed more phagolysosome formation and a stronger leptospire-killing ability to than mouse macrophages. Mononuclear-macrophages but not neutrophils represent the main infiltrating and anti-leptospiral phagocytes during leptospirosis. A lower level of phagosome-lysosome fusion may be responsible for the lower Leptospira-killing ability of human macrophages.

Peptidoglycan from the gut microbiota governs the lifespan of circulating phagocytes at homeostasis.

PubMed

Hergott, Christopher B; Roche, Aoife M; Tamashiro, Edwin; Clarke, Thomas B; Bailey, Aubrey G; Laughlin, Alice; Bushman, Frederic D; Weiser, Jeffrey N

2016-05-19

Maintenance of myeloid cell homeostasis requires continuous turnover of phagocytes from the bloodstream, yet whether environmental signals influence phagocyte longevity in the absence of inflammation remains unknown. Here, we show that the gut microbiota regulates the steady-state cellular lifespan of neutrophils and inflammatory monocytes, the 2 most abundant circulating myeloid cells and key contributors to inflammatory responses. Treatment of mice with broad-spectrum antibiotics, or with the gut-restricted aminoglycoside neomycin alone, accelerated phagocyte turnover and increased the rates of their spontaneous apoptosis. Metagenomic analyses revealed that neomycin altered the abundance of intestinal bacteria bearing γ-d-glutamyl-meso-diaminopimelic acid, a ligand for the intracellular peptidoglycan sensor Nod1. Accordingly, signaling through Nod1 was both necessary and sufficient to mediate the stimulatory influence of the flora on myeloid cell longevity. Stimulation of Nod1 signaling increased the frequency of lymphocytes in the murine intestine producing the proinflammatory cytokine interleukin 17A (IL-17A), and liberation of IL-17A was required for transmission of Nod1-dependent signals to circulating phagocytes. Together, these results define a mechanism through which intestinal microbes govern a central component of myeloid homeostasis and suggest perturbations of commensal communities can influence steady-state regulation of cell fate. © 2016 by The American Society of Hematology.

Intestinal Mononuclear Phagocytes in Health and Disease.

PubMed

Sanders, Theodore J; Yrlid, Ulf; Maloy, Kevin J

2017-01-01

The intestine is the tissue of the body with the highest constitutive exposure to foreign antigen and is also a common entry portal for many local and systemic pathogens. Therefore, the local immune system has the unenviable task of balancing efficient responses to dangerous pathogens with tolerance toward beneficial microbiota and food antigens. As in most tissues, the decision between tolerance and immunity is critically governed by the activity of local myeloid cells. However, the unique challenges posed by the intestinal environment have necessitated the development of several specialized mononuclear phagocyte populations with distinct phenotypic and functional characteristics that have vital roles in maintaining barrier function and immune homeostasis in the intestine. Intestinal mononuclear phagocyte populations, comprising dendritic cells and macrophages, are crucial for raising appropriate active immune responses against ingested pathogens. Recent technical advances, including microsurgical approaches allowing collection of cells migrating in intestinal lymph, intravital microscopy, and novel gene-targeting approaches, have led to clearer distinctions between mononuclear phagocyte populations in intestinal tissue. In this review, we present an overview of the various subpopulations of intestinal mononuclear phagocytes and discuss their phenotypic and functional characteristics. We also outline their roles in host protection from infection and their regulatory functions in maintaining immune tolerance toward beneficial intestinal antigens.

Peptidoglycan from the gut microbiota governs the lifespan of circulating phagocytes at homeostasis

PubMed Central

Hergott, Christopher B.; Roche, Aoife M.; Tamashiro, Edwin; Clarke, Thomas B.; Bailey, Aubrey G.; Laughlin, Alice; Bushman, Frederic D.

2016-01-01

Maintenance of myeloid cell homeostasis requires continuous turnover of phagocytes from the bloodstream, yet whether environmental signals influence phagocyte longevity in the absence of inflammation remains unknown. Here, we show that the gut microbiota regulates the steady-state cellular lifespan of neutrophils and inflammatory monocytes, the 2 most abundant circulating myeloid cells and key contributors to inflammatory responses. Treatment of mice with broad-spectrum antibiotics, or with the gut-restricted aminoglycoside neomycin alone, accelerated phagocyte turnover and increased the rates of their spontaneous apoptosis. Metagenomic analyses revealed that neomycin altered the abundance of intestinal bacteria bearing γ-d-glutamyl-meso-diaminopimelic acid, a ligand for the intracellular peptidoglycan sensor Nod1. Accordingly, signaling through Nod1 was both necessary and sufficient to mediate the stimulatory influence of the flora on myeloid cell longevity. Stimulation of Nod1 signaling increased the frequency of lymphocytes in the murine intestine producing the proinflammatory cytokine interleukin 17A (IL-17A), and liberation of IL-17A was required for transmission of Nod1-dependent signals to circulating phagocytes. Together, these results define a mechanism through which intestinal microbes govern a central component of myeloid homeostasis and suggest perturbations of commensal communities can influence steady-state regulation of cell fate. PMID:26989200

Ovarian phagocyte subsets and their distinct tissue distribution patterns.

PubMed

Carlock, Colin; Wu, Jean; Zhou, Cindy; Ross, April; Adams, Henry; Lou, Yahuan

2013-01-01

Ovarian macrophages, which play critical roles in various ovarian events, are probably derived from multiple lineages. Thus, a systemic classification of their subsets is a necessary first step for determination of their functions. Utilizing antibodies to five phagocyte markers, i.e. IA/IE (major histocompatibility complex class II), F4/80, CD11b (Mac-1), CD11c, and CD68, this study investigated subsets of ovarian phagocytes in mice. Three-color immunofluorescence and flow cytometry, together with morphological observation on isolated ovarian cells, demonstrated complicated phenotypes of ovarian phagocytes. Four macrophage and one dendritic cell subset, in addition to many minor phagocyte subsets, were identified. A dendritic cell-like population with a unique phenotype of CD11c(high)IA/IE⁻F4/80⁻ was also frequently observed. A preliminary age-dependent study showed dramatic increases in IA/IE⁺ macrophages and IA/IE⁺ dendritic cells after puberty. Furthermore, immunofluorescences on ovarian sections showed that each subset displayed a distinct tissue distribution pattern. The pattern for each subset may hint to their role in an ovarian function. In addition, partial isolation of ovarian macrophage subset using CD11b antibodies was attempted. Establishment of this isolation method may have provided us a tool for more precise investigation of each subset's functions at the cellular and molecular levels.

Macrophages redirect phagocytosis by non-professional phagocytes and influence inflammation.

PubMed

Han, Claudia Z; Juncadella, Ignacio J; Kinchen, Jason M; Buckley, Monica W; Klibanov, Alexander L; Dryden, Kelly; Onengut-Gumuscu, Suna; Erdbrügger, Uta; Turner, Stephen D; Shim, Yun M; Tung, Kenneth S; Ravichandran, Kodi S

2016-11-24

Professional phagocytes (such as macrophages) and non-professional phagocytes (such as epithelial cells) clear billions of apoptotic cells and particles on a daily basis. Although professional and non-professional macrophages reside in proximity in most tissues, whether they communicate with each other during cell clearance, and how this might affect inflammation, is not known. Here we show that macrophages, through the release of a soluble growth factor and microvesicles, alter the type of particles engulfed by non-professional phagocytes and influence their inflammatory response. During phagocytosis of apoptotic cells or in response to inflammation-associated cytokines, macrophages released insulin-like growth factor 1 (IGF-1). The binding of IGF-1 to its receptor on non-professional phagocytes redirected their phagocytosis, such that uptake of larger apoptotic cells was reduced whereas engulfment of microvesicles was increased. IGF-1 did not alter engulfment by macrophages. Macrophages also released microvesicles, whose uptake by epithelial cells was enhanced by IGF-1 and led to decreased inflammatory responses by epithelial cells. Consistent with these observations, deletion of IGF-1 receptor in airway epithelial cells led to exacerbated lung inflammation after allergen exposure. These genetic and functional studies reveal that IGF-1- and microvesicle-dependent communication between macrophages and epithelial cells can critically influence the magnitude of tissue inflammation in vivo.

The amelioration of phagocytic ability in microglial cells by curcumin through the inhibition of EMF-induced pro-inflammatory responses

PubMed Central

2014-01-01

Background Insufficient clearance by microglial cells, prevalent in several neurological conditions and diseases, is intricately intertwined with MFG-E8 expression and inflammatory responses. Electromagnetic field (EMF) exposure can elicit the pro-inflammatory activation and may also trigger an alteration of the clearance function in microglial cells. Curcumin has important roles in the anti-inflammatory and phagocytic process. Here, we evaluated the ability of curcumin to ameliorate the phagocytic ability of EMF-exposed microglial cells (N9 cells) and documented relative pathways. Methods N9 cells were pretreated with or without recombinant murine MFG-E8 (rmMFG-E8), curcumin and an antibody of toll-like receptor 4 (anti-TLR4), and subsequently treated with EMF or a sham exposure. Their phagocytic ability was evaluated using phosphatidylserine-containing fluorescent bioparticles. The pro-inflammatory activation of microglia was assessed via CD11b immunoreactivity and the production of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β) and nitric oxide (NO) via the enzyme-linked immunosorbent assay or the Griess test. We evaluated the ability of curcumin to ameliorate the phagocytic ability of EMF-exposed N9 cells, including checking the expression of MFG-E8, αvβ3 integrin, TLR4, nuclear factor-κB (NF-κB) and signal transducer and activator of transcription 3 (STAT3) using Western blotting. Results EMF exposure dramatically enhanced the expression of CD11b and depressed the phagocytic ability of N9 cells. rmMFG-E8 could clearly ameliorate the phagocytic ability of N9 cells after EMF exposure. We also found that EMF exposure significantly increased the secretion of pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β) and the production of NO; however, these increases were efficiently chilled by the addition of curcumin to the culture medium. This reduction led to the amelioration of the phagocytic ability of EMF-exposed N9 cells. Western blot analysis revealed that curcumin and naloxone restored the expression of MFG-E8 but had no effect on TLR4 and cytosolic STAT3. Moreover, curcumin significantly reduced the expression of NF-κB p65 in nuclei and phospho-STAT3 (p-STAT3) in cytosols and nuclei. Conclusions This study indicates that curcumin ameliorates the depressed MFG-E8 expression and the attenuated phagocytic ability of EMF-exposed N9 cells, which is attributable to the inhibition of the pro-inflammatory response through the NF-κB and STAT3 pathways. PMID:24645646

Sensitive Microplate Assay for Detection of Bactericidal Antibodies to Vibrio cholerae O139

PubMed Central

Attridge, Stephen R.; Johansson, Camilla; Trach, Dang D.; Qadri, Firdausi; Svennerholm, Ann-Mari

2002-01-01

A microplate assay for the detection of bactericidal antibodies to Vibrio cholerae O139 is described. The assay is sensitive, highly reproducible, specific, and convenient to perform. It has been used to demonstrate the induction of serum bactericidal antibodies in Vietnamese recipients of an oral, inactivated, bivalent O1/O139 vaccine, as well as in Bangladeshi patients with O139 disease. In both study groups there was a significant inverse correlation between the preexposure level of antibodies in serum and the magnitude of the subsequent bactericidal response. Although infection generated stronger responses than vaccination, the proportion of responders was similar among individuals with low background titers. PMID:11874883

Combined treatment of UVA irradiation and antibiotics induces greater bactericidal effects on Vibrio parahaemolyticus.

PubMed

Hou, Yanfei; Nakahashi, Mutsumi; Mawatari, Kazuaki; Shimohata, Takaaki; Uebanso, Takashi; Harada, Yumi; Tsunedomi, Akari; Emoto, Takahiro; Akutagawa, Masatake; Kinouchi, Yohsuke; Takahashi, Akira

2016-01-01

The presence of antibiotics in the environment and their subsequent impact on the development of multi-antibiotic resistant bacteria has raised concerns globally. Consequently, much research is focused on a method to produce a better disinfectant. We have established a disinfectant system using UVA-LED that inactivates pathogenic bacteria. We assessed the bactericidal efficiency of a combination of UVA-LED and antibiotics against Vibrio parahaemolyticus. Combined use of antibiotic drugs and UVA irradiation was more bactericidal than UVA irradiation or antibacterial drugs alone. The bactericidal synergy was observed at low concentrations of each drug that are normally unable to kill the bacteria. This combination has the potential to become a sterilization technology.

LED array designing and its bactericidal effect researching on Pseudomonas aeruginosa in vitro

NASA Astrophysics Data System (ADS)

Fang, Jing; Xing, Jin; Gao, Liucun; Shen, Benjian; Kang, Hongxiang; Jie, Liang; Peng, Chen

2015-10-01

Lights with some special waveband and output power density have a bactericidal effect to some special bacteria. In this paper, the bactericidal effect of light at wavelength of 470 nm on P. aeruginosa (ATCC 27853) is researched with different irradiation dose. The light source is a LED array which is obtained by incoherent combine of 36 LEDs with emitting wavelength of 470 nm. The P. aeruginosa suspension is exposed with the LED array at the light power density of 100 mW/cm2 with exposures time of 0, 5, 10, 20, 40, and 80 min, respectively. The numbers of CFU are then determined by serial dilutions on LB agar plates. The bactericidal effect research results of 470 nm LED on P. aeruginosa show that the killing ratio increases with increasing of the exposure time. For the 80 min irradiation, as much as 92.4% reduction of P. aeruginosa is achieved. The results indicate that, in vitro, 470-nm lights produce dose dependent bactericidal effects on P. aeruginosa.

Bactericidal activity of glutaraldehyde-like compounds from olive products.

PubMed

Medina, Eduardo; Brenes, Manuel; García, Aranzazu; Romero, Concepción; de Castro, Antonio

2009-12-01

The bactericidal effects of several olive compounds (nonenal, oleuropein, tyrosol, the dialdehydic form of decarboxymethyl elenolic acid either free [EDA] or linked to tyrosol [TyEDA] or to hydroxytyrosol [HyEDA]), other food phenolic compounds (catechin, epicatechin, eugenol, thymol, carvacrol, and carnosic acid), and commercial disinfectants (glutaraldehyde [GTA] and ortho-phthalaldehyde [OPA]), were tested against strains of Pseudomonas fluorescens, Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli. It was found that the bactericidal activities of olive GTA-like compounds (EDA, HyEDA, and TyEDA) were greater than those exerted by several food phenolic substances. Surprisingly, these olive antimicrobials were as active as the synthetic biocides GTA and OPA against the four bacteria studied. Thus, it has been proposed that the bactericidal activity of the main olive antimicrobials is primarily due to their dialdehydic structure, which is similar to that of the commercial biocides GTA and OPA. Our results clearly reveal that olive GTA-like compounds possess a strong bactericidal activity even greater than that of other food phenolic compounds or synthetic biocides.

Influence of nanoscale topology on bactericidal efficiency of black silicon surfaces

NASA Astrophysics Data System (ADS)

Linklater, Denver P.; Khuong Duy Nguyen, Huu; Bhadra, Chris M.; Juodkazis, Saulius; Ivanova, Elena P.

2017-06-01

The nanostructuring of materials to create bactericidal and antibiofouling surfaces presents an exciting alternative to common methods of preventing bacterial adhesion. The fabrication of synthetic bactericidal surfaces has been inspired by the anti-wetting and anti-biofouling properties of insect wings, and other topologies found in nature. Black silicon is one such synthetic surfaces which has established bactericidal properties. In this study we show that time-dependent plasma etching of silicon wafers using 15, 30, and 45 min etching intervals, is able to produce different surface geometries with linearly increasing heights of approximately 280, 430, and 610 nm, respectively. After incubation on these surfaces with Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa bacterial cells it was established that smaller, more densely packed pillars exhibited the greatest bactericidal activity with 85% and 89% inactivation of bacterial cells, respectively. The decrease in the pillar heights, pillar cap diameter and inter-pillar spacing corresponded to a subsequent decrease in the number of attached cells for both bacterial species.

Effect of Bromide-Hypochlorite Bactericides on Microorganisms1

PubMed Central

Shere, Lewis; Kelley, Maurice J.; Richardson, J. Harold

1962-01-01

A new principle in compounding stable, granular bactericidal products led to unique combinations of a water-soluble inorganic bromide salt with a hypochlorite-type disinfectant of either inorganic or organic type. Microbiological results are shown for an inorganic bactericide composed of chlorinated trisodium phosphate containing 3.1% “available chlorine” and 2% potassium bromide, and for an organic bactericide formulated from sodium dichloroisocyanurate so as to contain 13.4% “available chlorine” and 8% potassium bromide. Comparison of these products with their nonbromide counterparts are reported for Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Streptococcus lactis, Aerobacter aerogenes, and Proteus vulgaris. Test methods employed were the Chambers test, the A.O.A.C. Germicidal and Detergent Sanitizer-Official test, and the Available Chlorine Germicidal Equivalent Concentration test. The minimal killing concentrations for the bromide-hypochlorite bactericides against this variety of organisms were reduced by a factor 2 to 24 times those required for similar hypochlorite-type disinfectants not containing the bromide. PMID:13977149

Antagonism between Bacteriostatic and Bactericidal Antibiotics Is Prevalent

PubMed Central

Lázár, Viktória; Papp, Balázs; Arnoldini, Markus; Abel zur Wiesch, Pia; Busa-Fekete, Róbert; Fekete, Gergely; Pál, Csaba; Ackermann, Martin; Bonhoeffer, Sebastian

2014-01-01

Combination therapy is rarely used to counter the evolution of resistance in bacterial infections. Expansion of the use of combination therapy requires knowledge of how drugs interact at inhibitory concentrations. More than 50 years ago, it was noted that, if bactericidal drugs are most potent with actively dividing cells, then the inhibition of growth induced by a bacteriostatic drug should result in an overall reduction of efficacy when the drug is used in combination with a bactericidal drug. Our goal here was to investigate this hypothesis systematically. We first constructed time-kill curves using five different antibiotics at clinically relevant concentrations, and we observed antagonism between bactericidal and bacteriostatic drugs. We extended our investigation by performing a screen of pairwise combinations of 21 different antibiotics at subinhibitory concentrations, and we found that strong antagonistic interactions were enriched significantly among combinations of bacteriostatic and bactericidal drugs. Finally, since our hypothesis relies on phenotypic effects produced by different drug classes, we recreated these experiments in a microfluidic device and performed time-lapse microscopy to directly observe and quantify the growth and division of individual cells with controlled antibiotic concentrations. While our single-cell observations supported the antagonism between bacteriostatic and bactericidal drugs, they revealed an unexpected variety of cellular responses to antagonistic drug combinations, suggesting that multiple mechanisms underlie the interactions. PMID:24867991

Pathophysiology and Treatments of Oxidative Injury in Ischemic Stroke: Focus on the Phagocytic NADPH Oxidase 2

PubMed Central

Carbone, Federico; Teixeira, Priscila Camillo; Braunersreuther, Vincent; Mach, François; Vuilleumier, Nicolas

2015-01-01

Abstract Significance: Phagocytes play a key role in promoting the oxidative stress after ischemic stroke occurrence. The phagocytic NADPH oxidase (NOX) 2 is a membrane-bound enzyme complex involved in the antimicrobial respiratory burst and free radical production in these cells. Recent Advances: Different oxidants have been shown to induce opposite effects on neuronal homeostasis after a stroke. However, several experimental models support the detrimental effects of NOX activity (especially the phagocytic isoform) on brain recovery after stroke. Therapeutic strategies selectively targeting the neurotoxic ROS and increasing neuroprotective oxidants have recently produced promising results. Critical Issues: NOX2 might promote carotid plaque rupture and stroke occurrence. In addition, NOX2-derived reactive oxygen species (ROS) released by resident and recruited phagocytes enhance cerebral ischemic injury, activating the inflammatory apoptotic pathways. The aim of this review is to update evidence on phagocyte-related oxidative stress, focusing on the role of NOX2 as a potential therapeutic target to reduce ROS-related cerebral injury after stroke. Future Directions: Radical scavenger compounds (such as Ebselen and Edaravone) are under clinical investigation as a therapeutic approach against stroke. On the other hand, NOX inhibition might represent a promising strategy to prevent the stroke-related injury. Although selective NOX inhibitors are not yet available, nonselective compounds (such as apocynin and fasudil) provided encouraging results in preclinical studies. Whereas additional studies are needed to better evaluate this therapeutic potential in human beings, the development of specific NOX inhibitors (such as monoclonal antibodies, small-molecule inhibitors, or aptamers) might further improve brain recovery after stroke. Antioxid. Redox Signal. 23, 460–489. PMID:24635113

Effect of intravenous plasma transfusion on granulocyte and monocyte oxidative and phagocytic activity in dairy calves with failure of passive immunity.

PubMed

Yang, Victoria C; Rayburn, Maire C; Chigerwe, Munashe

2017-12-01

Plasma administration has been recommended in calves older than 48h with failure of passive immunity (FPI) to provide immunity consistent with adequate colostral ingestion. However, the protective serum immunoglobulin G (IgG) concentrations (≥1000mg/dL) of plasma derived IgG only lasts up to 12h. In addition to IgG, maternally derived colostral cells also confer immunity. The objective of the study was to determine the effect of intravenous plasma transfusion on granulocyte and monocyte oxidative and phagocytic activity in calves with FPI. Twenty-seven, one day-old, Jersey calves were assigned into 3 groups. The colostral (CL, N=9) group received 3L of colostrum once by oroesophageal tubing. Two other groups of calves received 1L of colostrum once by oroesophageal tubing and were assigned based on their health status (sick or non-sick) at 4days of age, as the sick-group (SG, N=7) or the non-sick (NG, N=11) groups. At 4days of age, the SG and NG groups were administered plasma intravenously at 30mL/kg. Granulocyte and monocyte oxidative and phagocytic activity was determined by flow cytometry. There was no significant difference in the granulocyte and monocyte oxidative or phagocytic activity among the 3 groups (P>0.05). Plasma administration had no significant effect on the oxidative or phagocytic activity of granulocytes or monocytes. In clinical practice, plasma administration for enhancing oxidative or phagocytic activity of granulocytes or monocytes, alone, might not be justified in calves with FPI. Copyright © 2017 Elsevier Ltd. All rights reserved.

Classification and phagocytosis of circulating haemocytes in Chinese mitten crab (Eriocheir sinensis) and the effect of extrinsic stimulation on circulating haemocytes in vivo.

PubMed

Lv, Sunjian; Xu, Jiehao; Zhao, Jing; Yin, Na; Lu, Binjie; Li, Song; Chen, Yuyin; Xu, Haisheng

2014-08-01

Eriocheir sinensis (Henri Milne Edwards 1854) is one of the most important aquaculture species in China. In this investigation, we characterised the different types of haemocytes of E. sinensis using light and electron microscopy combined with cytochemical analysis and determined the in vivo phagocytic ability of different haemocyte types by injecting polystyrene beads. The haemocytes of E. sinensis were divided into three types: hyalinocytes, semigranulocytes and granulocytes. The hyalinocytes had no or few cytoplasmic granules; the semigranulocytes contained abundant small granules and a few large refractile cytoplasmic granules; and the granulocytes contained numerous large refractile cytoplasmic granules. The hyalinocytes were demonstrated to be the most abundant circulating haemocytes and the most avid phagocytic haemocytes, accounting for approximately 88.7% of the total phagocytes. The haemocyte-containing granules displayed limited phagocytic ability, with approximately 5.0% of granulocytes and 6.3% of semigranulocytes displaying positive phagocytic ability against the invading polystyrene beads in vivo. After injection with Aeromonas hydrophila, Bacillus subtilis and different concentrations of lipopolysaccharide for 0.25, 0.5, 1, 2, 4, 6 and 8 h, all three types of haemocytes experienced dramatic decline and then rapid recovery to their initial levels. A high concentration of lipopolysaccharide and A. hydrophila were extremely toxic to the crabs, as they induced a more serious loss of haemocytes compared with a low concentration of lipopolysaccharide and B. subtilis. Overall, the results obtained in this study indicate that a small proportion of the haemocytes of E. sinensis contributed to the phagocytic process, and the migration of haemocytes and haemocyte lysis were most likely a prominent pathway for pathogen elimination. Copyright © 2014 Elsevier Ltd. All rights reserved.

Surface code—biophysical signals for apoptotic cell clearance

NASA Astrophysics Data System (ADS)

Biermann, Mona; Maueröder, Christian; Brauner, Jan M.; Chaurio, Ricardo; Janko, Christina; Herrmann, Martin; Muñoz, Luis E.

2013-12-01

Apoptotic cell death and the clearance of dying cells play an important and physiological role in embryonic development and normal tissue turnover. In contrast to necrosis, apoptosis proceeds in an anti-inflammatory manner. It is orchestrated by the timed release and/or exposure of so-called ‘find-me’, ‘eat me’ and ‘tolerate me’ signals. Mononuclear phagocytes are attracted by various ‘find-me’ signals, including proteins, nucleotides, and phospholipids released by the dying cell, whereas the involvement of granulocytes is prevented via ‘stay away’ signals. The exposure of anionic phospholipids like phosphatidylserine (PS) by apoptotic cells on the outer leaflet of the plasma membrane is one of the main ‘eat me’ signals. PS is recognized by a number of innate receptors as well as by soluble bridging molecules on the surface of phagocytes. Importantly, phagocytes are able to discriminate between viable and apoptotic cells both exposing PS. Due to cytoskeleton remodeling PS has a higher lateral mobility on the surfaces of apoptotic cells thereby promoting receptor clustering on the phagocyte. PS not only plays an important role in the engulfment process, but also acts as ‘tolerate me’ signal inducing the release of anti-inflammatory cytokines by phagocytes. An efficient and fast clearance of apoptotic cells is required to prevent secondary necrosis and leakage of intracellular danger signals into the surrounding tissue. Failure or prolongation of the clearance process leads to the release of intracellular antigens into the periphery provoking inflammation and development of systemic inflammatory autoimmune disease like systemic lupus erythematosus. Here we review the current findings concerning apoptosis-inducing pathways, important players of apoptotic cell recognition and clearance as well as the role of membrane remodeling in the engulfment of apoptotic cells by phagocytes.

Susceptibility of Meningococcal Strains Responsible for Two Serogroup B Outbreaks on U.S. University Campuses to Serum Bactericidal Activity Elicited by the MenB-4C Vaccine.

PubMed

Rossi, Raffaella; Beernink, Peter T; Giuntini, Serena; Granoff, Dan M

2015-12-01

In 2013 and 2014, two U.S. universities had meningococcal serogroup B outbreaks (a total of 14 cases) caused by strains from two different clonal complexes. To control the outbreaks, students were immunized with a serogroup B meningococcal vaccine (Novartis) that was not yet licensed in the United States. The vaccine (referred to as MenB-4C) contains four components capable of eliciting bactericidal activity. Both outbreak strains had high expression levels of two of the vaccine antigens (subfamily B factor H binding protein [FHbp] and neisserial heparin binding antigen [NHba]); the university B outbreak strain also had moderate expression of a third antigen, NadA. We investigated the bactericidal activity of sera from mice immunized with FHbp, NHba, or NadA and sera from MenB-4C-immunized infant macaques and an adult human. The postimmunization bactericidal activity of the macaque or human serum against isolates from university B with FHbp identification (ID) 1 that exactly matched the vaccine FHbp sequence variant was 8- to 21-fold higher than that against isolates from university A with FHbp ID 276 (96% identity to the vaccine antigen). Based on the bactericidal activity of mouse antisera to FHbp, NadA, or NHba and macaque or human postimmunization serum that had been depleted of anti-FHbp antibody, the bactericidal activity against both outbreak strains largely or entirely resulted from antibodies to FHbp. Thus, despite the high level of strain expression of FHbp from a subfamily that matched the vaccine antigen, there can be large differences in anti-FHbp bactericidal activity induced by MenB-4C vaccination. Further, strains with moderate to high NadA and/or NHba expression can be resistant to anti-NadA or anti-NHba bactericidal activity elicited by MenB-4C vaccination. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Activation of cathepsins B and L in mouse lymphosarcoma tissue under the effect of cyclophosphamide is associated with apoptosis induction and infiltration by mononuclear phagocytes.

PubMed

Zhanaeva, S Ya; Mel'nikova, E V; Trufakin, V A; Korolenko, T A

2013-11-01

We analyzed activities of lysosomal cystein cathepsins B and L in mouse LS lymphosarcoma and its drug-resistant RLS 40 strain and their correlations with the dynamics of the percentage of cells with fragmented DNA and CD14 (+) phagocytes over 3 days after cyclophosphamide injection. LS regression and inhibition of RLS 40 growth after cyclophosphamide injection were paralleled by an increase in cathepsins B and L activities in tumor tissues. The antitumor effect of cyclophosphamide associated with apoptosis intensity and protease activities were significantly higher in LS. Positive correlations between activities of cathepsins B and L and the LS tissue content of cells with fragmented DNA and CD14 (+) phagocytes and negative correlations thereof with tumor weight were detected. It seems that the increase in cathepsins B and L activities in LS tissues was caused by cyclophosphamide induction of apoptosis and depended on the level of tumor cell infiltration with mononuclear phagocytes.

Surface modification of nanoparticles enables selective evasion of phagocytic clearance by distinct macrophage phenotypes

NASA Astrophysics Data System (ADS)

Qie, Yaqing; Yuan, Hengfeng; von Roemeling, Christina A.; Chen, Yuanxin; Liu, Xiujie; Shih, Kevin D.; Knight, Joshua A.; Tun, Han W.; Wharen, Robert E.; Jiang, Wen; Kim, Betty Y. S.

2016-05-01

Nanomedicine is a burgeoning industry but an understanding of the interaction of nanomaterials with the immune system is critical for clinical translation. Macrophages play a fundamental role in the immune system by engulfing foreign particulates such as nanoparticles. When activated, macrophages form distinct phenotypic populations with unique immune functions, however the mechanism by which these polarized macrophages react to nanoparticles is unclear. Furthermore, strategies to selectively evade activated macrophage subpopulations are lacking. Here we demonstrate that stimulated macrophages possess higher phagocytic activities and that classically activated (M1) macrophages exhibit greater phagocytic capacity than alternatively activated (M2) macrophages. We show that modification of nanoparticles with polyethylene-glycol results in decreased clearance by all macrophage phenotypes, but importantly, coating nanoparticles with CD47 preferentially lowers phagocytic activity by the M1 phenotype. These results suggest that bio-inspired nanoparticle surface design may enable evasion of specific components of the immune system and provide a rational approach for developing immune tolerant nanomedicines.

Tunable particles alter macrophage uptake based on combinatorial effects of physical properties

PubMed Central

Garapaty, Anusha

2017-01-01

Abstract The ability to tune phagocytosis of particle‐based therapeutics by macrophages can enhance their delivery to macrophages or reduce their phagocytic susceptibility for delivery to non‐phagocytic cells. Since phagocytosis is affected by the physical and chemical properties of particles, it is crucial to identify any interplay between physical properties of particles in altering phagocytic interactions. The combinatorial effect of physical properties size, shape and stiffness was investigated on Fc receptor mediated macrophage interactions by fabrication of layer‐by‐layer tunable particles of constant surface chemistry. Our results highlight how changing particle stiffness affects phagocytic interaction intricately when combined with varying size or shape. Increase in size plays a dominant role over reduction in stiffness in reducing internalization by macrophages for spherical particles. Internalization of rod‐shaped, but not spherical particles, was highly dependent on stiffness. These particles demonstrate the interplay between size, shape and stiffness in interactions of Fc‐functionalized particles with macrophages during phagocytosis. PMID:29313025

Caspase Activity Is Required for Engulfment of Apoptotic Cells

PubMed Central

Shklyar, Boris; Levy-Adam, Flonia; Mishnaevski, Ketty

2013-01-01

Clearance of apoptotic cells by phagocytic neighbors is crucial for normal development of multicellular organisms. However, how phagocytes discriminate between healthy and dying cells remains poorly understood. We focus on glial phagocytosis of apoptotic neurons during development of the Drosophila central nervous system. We identified phosphatidylserine (PS) as a ligand on apoptotic cells for the phagocytic receptor Six Microns Under (SIMU) and report that PS alone is not sufficient for engulfment. Our data reveal that, additionally to PS exposure, caspase activity is required for clearance of apoptotic cells by phagocytes. Here we demonstrate that SIMU recognizes and binds PS on apoptotic cells through its N-terminal EMILIN (EMI), Nimrod 1 (NIM1), and NIM2 repeats, whereas the C-terminal NIM3 and NIM4 repeats control SIMU affinity to PS. Based on the structure-function analysis of SIMU, we discovered a novel mechanism of internal inhibition responsible for differential affinities of SIMU to its ligand which might prevent elimination of living cells exposing PS on their surfaces. PMID:23754750

Intracellular survival of Staphylococcus aureus during persistent infection in the insect Tenebrio molitor.

PubMed

McGonigle, John E; Purves, Joanne; Rolff, Jens

2016-06-01

Survival of bacteria within host cells and tissues presents a challenge to the immune systems of higher organisms. Escape from phagocytic immune cells compounds this issue, as immune cells become potential vehicles for pathogen dissemination. However, the duration of persistence within phagocytes and its contribution to pathogen load has yet to be determined. We investigate the immunological significance of intracellular persistence within the insect model Tenebrio molitor, assessing the extent, duration and location of bacterial recovery during a persistent infection. Relative abundance of Staphylococcus aureus in both intracellular and extracellular fractions was determined over 21 days, and live S. aureus were successfully recovered from both the hemolymph and within phagocytic immune cells across the entire time course. The proportion of bacteria recovered from within phagocytes also increased over time. Our results show that to accurately estimate pathogen load it is vital to account for bacteria persisting within immune cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

Phenotypic and functional consequences of different isolation protocols on skin mononuclear phagocytes.

PubMed

Botting, Rachel A; Bertram, Kirstie M; Baharlou, Heeva; Sandgren, Kerrie J; Fletcher, James; Rhodes, Jake W; Rana, Hafsa; Plasto, Toby M; Wang, Xin Maggie; Lim, Jake J K; Barnouti, Laith; Kohout, Mark P; Papadopoulos, Tim; Merten, Steve; Olbourne, Norman; Cunningham, Anthony L; Haniffa, Muzlifah; Harman, Andrew N

2017-06-01

Mononuclear phagocytes are present in skin and mucosa and represent one of the first lines of defense against invading pathogens, which they detect via an array of pathogen-binding receptors expressed on their surface. However, their extraction from tissue is difficult, and the isolation technique used has functional consequences on the cells obtained. Here, we compare mononuclear phagocytes isolated from human skin using either enzymatic digestion or spontaneous migration. Cells isolated via enzymatic digestion are in an immature state, and all subsets are easily defined. However, cells isolated by spontaneous migration are in a mature state, and CD141 cross-presenting DCs (cDC1) are more difficult to define. Different pathogen-binding receptors are susceptible to cleavage by blends of collagenase, demonstrating that great care must be taken in choosing the correct enzyme blend to digest tissue if carrying out pathogen-interaction assays. Finally, we have optimized mononuclear phagocyte culture conditions to enhance their survival after liberation from the tissue. © The Author(s).

Far beyond Phagocytosis: Phagocyte-Derived Extracellular Traps Act Efficiently against Protozoan Parasites In Vitro and In Vivo.

PubMed

Silva, Liliana M R; Muñoz-Caro, Tamara; Burgos, Rafael A; Hidalgo, Maria A; Taubert, Anja; Hermosilla, Carlos

2016-01-01

Professional mononuclear phagocytes such as polymorphonuclear neutrophils (PMN), monocytes, and macrophages are considered as the first line of defence against invasive pathogens. The formation of extracellular traps (ETs) by activated mononuclear phagocytes is meanwhile well accepted as an effector mechanism of the early host innate immune response acting against microbial infections. Recent investigations showed evidence that ETosis is a widely spread effector mechanism in vertebrates and invertebrates being utilized to entrap and kill bacteria, fungi, viruses, and protozoan parasites. ETs are released in response to intact protozoan parasites or to parasite-specific antigens in a controlled cell death process. Released ETs consist of nuclear DNA as backbone adorned with histones, antimicrobial peptides, and phagocyte-specific granular enzymes thereby producing a sticky extracellular matrix capable of entrapping and killing pathogens. This review summarizes recent data on protozoa-induced ETosis. Special attention will be given to molecular mechanisms of protozoa-induced ETosis and on its consequences for the parasites successful reproduction and life cycle accomplishment.

Phenotypic and functional consequences of different isolation protocols on skin mononuclear phagocytes

PubMed Central

Botting, Rachel A.; Bertram, Kirstie M.; Baharlou, Heeva; Sandgren, Kerrie J.; Fletcher, James; Rhodes, Jake W.; Rana, Hafsa; Plasto, Toby M.; Wang, Xin Maggie; Lim, Jake J. K.; Barnouti, Laith; Kohout, Mark P.; Papadopoulos, Tim; Merten, Steve; Olbourne, Norman; Cunningham, Anthony L.; Haniffa, Muzlifah; Harman, Andrew N.

2017-01-01

Mononuclear phagocytes are present in skin and mucosa and represent one of the first lines of defense against invading pathogens, which they detect via an array of pathogen-binding receptors expressed on their surface. However, their extraction from tissue is difficult, and the isolation technique used has functional consequences on the cells obtained. Here, we compare mononuclear phagocytes isolated from human skin using either enzymatic digestion or spontaneous migration. Cells isolated via enzymatic digestion are in an immature state, and all subsets are easily defined. However, cells isolated by spontaneous migration are in a mature state, and CD141 cross-presenting DCs (cDC1) are more difficult to define. Different pathogen-binding receptors are susceptible to cleavage by blends of collagenase, demonstrating that great care must be taken in choosing the correct enzyme blend to digest tissue if carrying out pathogen-interaction assays. Finally, we have optimized mononuclear phagocyte culture conditions to enhance their survival after liberation from the tissue. PMID:28270408

Immune Defenses of the Invasive Apple Snail Pomacea canaliculata (Caenogastropoda, Ampullariidae): Phagocytic Hemocytes in the Circulation and the Kidney

PubMed Central

Vega, Israel A.; Castro-Vazquez, Alfredo

2015-01-01

Hemocytes in the circulation and kidney islets, as well as their phagocytic responses to microorganisms and fluorescent beads, have been studied in Pomacea canaliculata, using flow cytometry, light microscopy (including confocal laser scanning microscopy) and transmission electron microscopy (TEM). Three circulating hemocyte types (hyalinocytes, agranulocytes and granulocytes) were distinguished by phase contrast microscopy of living cells and after light and electron microscopy of fixed material. Also, three different populations of circulating hemocytes were separated by flow cytometry, which corresponded to the three hemocyte types. Hyalinocytes showed a low nucleus/cytoplasm ratio, and no apparent granules in stained material, but showed granules of moderate electron density under TEM (L granules) and at least some L granules appear acidic when labeled with LysoTracker Red. Both phagocytic and non-phagocytic hyalinocytes lose most (if not all) L granules when exposed to microorganisms in vitro. The phagosomes formed differed whether hyalinocytes were exposed to yeasts or to Gram positive or Gram negative bacteria. Agranulocytes showed a large nucleus/cytoplasm ratio and few or no granules. Granulocytes showed a low nucleus/cytoplasm ratio and numerous eosinophilic granules after staining. These granules are electron dense and rod-shaped under TEM (R granules). Granulocytes may show merging of R granules into gigantic ones, particularly when exposed to microorganisms. Fluorescent bead exposure of sorted hemocytes showed phagocytic activity in hyalinocytes, agranulocytes and granulocytes, but the phagocytic index was significantly higher in hyalinocytes. Extensive hemocyte aggregates ('islets') occupy most renal hemocoelic spaces and hyalinocyte-like cells are the most frequent component in them. Presumptive glycogen deposits were observed in most hyalinocytes in renal islets (they also occur in the circulation but less frequently) and may mean that hyalinocytes participate in the storage and circulation of this compound. Injection of microorganisms in the foot results in phagocytosis by hemocytes in the islets, and the different phagosomes formed are similar to those in circulating hyalinocytes. Dispersed hemocytes were obtained after kidney collagenase digestion and cell sorting, and they were able to phagocytize fluorescent beads. A role for the kidney as an immune barrier is proposed for this snail. PMID:25893243

Immune Defenses of the Invasive Apple Snail Pomacea canaliculata (Caenogastropoda, Ampullariidae): Phagocytic Hemocytes in the Circulation and the Kidney.

PubMed

Cueto, Juan A; Rodriguez, Cristian; Vega, Israel A; Castro-Vazquez, Alfredo

2015-01-01

Hemocytes in the circulation and kidney islets, as well as their phagocytic responses to microorganisms and fluorescent beads, have been studied in Pomacea canaliculata, using flow cytometry, light microscopy (including confocal laser scanning microscopy) and transmission electron microscopy (TEM). Three circulating hemocyte types (hyalinocytes, agranulocytes and granulocytes) were distinguished by phase contrast microscopy of living cells and after light and electron microscopy of fixed material. Also, three different populations of circulating hemocytes were separated by flow cytometry, which corresponded to the three hemocyte types. Hyalinocytes showed a low nucleus/cytoplasm ratio, and no apparent granules in stained material, but showed granules of moderate electron density under TEM (L granules) and at least some L granules appear acidic when labeled with LysoTracker Red. Both phagocytic and non-phagocytic hyalinocytes lose most (if not all) L granules when exposed to microorganisms in vitro. The phagosomes formed differed whether hyalinocytes were exposed to yeasts or to Gram positive or Gram negative bacteria. Agranulocytes showed a large nucleus/cytoplasm ratio and few or no granules. Granulocytes showed a low nucleus/cytoplasm ratio and numerous eosinophilic granules after staining. These granules are electron dense and rod-shaped under TEM (R granules). Granulocytes may show merging of R granules into gigantic ones, particularly when exposed to microorganisms. Fluorescent bead exposure of sorted hemocytes showed phagocytic activity in hyalinocytes, agranulocytes and granulocytes, but the phagocytic index was significantly higher in hyalinocytes. Extensive hemocyte aggregates ('islets') occupy most renal hemocoelic spaces and hyalinocyte-like cells are the most frequent component in them. Presumptive glycogen deposits were observed in most hyalinocytes in renal islets (they also occur in the circulation but less frequently) and may mean that hyalinocytes participate in the storage and circulation of this compound. Injection of microorganisms in the foot results in phagocytosis by hemocytes in the islets, and the different phagosomes formed are similar to those in circulating hyalinocytes. Dispersed hemocytes were obtained after kidney collagenase digestion and cell sorting, and they were able to phagocytize fluorescent beads. A role for the kidney as an immune barrier is proposed for this snail.

Propionibacterium acnes induces an adjuvant effect in B-1 cells and affects their phagocyte differentiation via a TLR2-mediated mechanism.

PubMed

Gambero, Monica; Teixeira, Daniela; Butin, Liane; Ishimura, Mayari Eika; Mariano, Mario; Popi, Ana Flavia; Longo-Maugéri, Ieda Maria

2016-09-01

B-1 lymphocytes are present in large numbers in the mouse peritoneal cavity, as are macrophages, and are responsible for natural IgM production. These lymphocytes migrate to inflammatory foci and are also involved in innate immunity. It was also demonstrated that B-1 cells are able to differentiated into phagocytes (B-1CDP), which is characterized by expression of F4/80 and increased phagocytic activity. B-1 cell responses to antigens and adjuvants are poorly characterized. It has been shown that Propionibacterium acnes suspensions induce immunomodulatory effects in both macrophages and B-2 lymphocytes. We recently demonstrated that this bacterium has the ability to increase B-1 cell populations both in vitro and in vivo. P. acnes induces B-1CDP differentiation, increases the expression of TLR2, TLR4 and TLR9 and augments the expression of CD80, CD86 and CD40 in B-1 and B-1CDP cells. Because P. acnes has been shown to modulate TLR expression, in this study, we investigated the role of TLR2 and TLR4 in B-1 cell population, including B-1CDP differentiation and phagocytic activity in vitro and in vivo. Interestingly, we have demonstrated that TLR2 signaling could be involved in the increase in the B-1 cell population induced by P. acnes. Furthermore, the early differentiation of B-1CDP is also dependent of TLR2. It was also observed that TLR signals also interfere in the phagocytic ability of B-1 cells and their phagocytes. According to these data, it is clear that P. acnes promotes an important adjuvant effect in B-1 cells by inducing them to differentiate into B-1CDP cells and modulates their phagocytic functions both in vivo and in vitro. Moreover, most of these effects are mediated primarily via TLR2. These data reinforce the findings that such bacterial suspensions have powerful adjuvant properties. The responses of B-1 cells to exogenous stimulation indicate that these cells are important to the innate immune response. Copyright © 2016 Elsevier GmbH. All rights reserved.

A HISTOLOGICAL STUDY OF TYPHOID FEVER

PubMed Central

Mallory, F. B.

1898-01-01

The typhoid bacillus produces a mild diffusible toxine, partly within the intestinal tract, partly within the blood and organs of the body. This toxine produces proliferation of endothelial cells which acquire for a certain length of time malignant properties. The new-formed cells are epithelioid in character, have irregular, lightly staining, eccentrically situated nuclei, abundant, sharply defined, acidophilic protoplasm, and are characterized by marked phagocytic properties. These phagocytic cells are produced most abundantly along the line of absorption from the intestinal tract, both in the lymphatic apparatus and in the blood-vessels. They are also produced by distribution of the toxine through the general circulation, in greatest numbers where the circulation is slowest. Finally, they are produced all over the body in the lymphatic spaces and vessels by absorption of the toxine eliminated from the blood-vessels. The swelling of the intestinal lymphoid tissue of the mesenteric lymph nodes, and of the spleen is due almost entirely to the formation of phagocytic cells. The necrosis of the intestinal lymphoid tissue is accidental in nature and is caused through occlusion of the veins and capillaries by fibrinous thrombi, which owe their origin to degeneration of phagocytic cells beneath the lining endothelium of the vessels. Two varieties of focal lesions occur in the liver: one consists of the formation of phagocytic cells in the lymph spaces and vessels around the portal vessels under the action of the toxine absorbed by the lymphatics; the other is due to obstruction of liver capillaries by phagocytic cells derived in small part from the lining endothelium of the liver capillaries, but chiefly by embolism through the portal circulation of cells originating from the endothelium of the blood-vessels of the intestine and spleen. The liver cells lying between the occluded capillaries undergo necrosis and disappear. Later the foci of cells degenerate and fibrin forms between them. Invasion with polymorphonuclear leucocytes is rare. Many of the phagocytic cells pass through the liver and lungs, and get into the general circulation. A few come from the abdominal lymphatics through the thoracic duct. PMID:19866884

Phagocytic activities of hemocytes from the deep-sea symbiotic mussels Bathymodiolus japonicus, B. platifrons, and B. septemdierum.

PubMed

Tame, Akihiro; Yoshida, Takao; Ohishi, Kazue; Maruyama, Tadashi

2015-07-01

Deep-sea mytilid mussels harbor symbiotic bacteria in their gill epithelial cells that are horizontally or environmentally transmitted to the next generation of hosts. To understand the immune defense system in deep-sea symbiotic mussels, we examined the hemocyte populations of the symbiotic Bathymodiolus mussel species Bathymodiolus japonicus, Bathymodiolus platifrons, and Bathymodiolus septemdierum, and characterized three types of hemocytes: agranulocytes (AGs), basophilic granulocytes (BGs), and eosinophilic granulocytes (EGs). Of these, the EG cells were the largest (diameter, 8.4-10.0 μm) and had eosinophilic cytoplasm with numerous eosinophilic granules (diameter, 0.8-1.2 μm). Meanwhile, the BGs were of medium size (diameter, 6.7-8.0 μm) and contained small basophilic granules (diameter, 0.3-0.4 μm) in basophilic cytoplasm, and the AGs, the smallest of the hemocytes (diameter, 4.8-6.0 μm), had basophilic cytoplasm lacking granules. A lectin binding assay revealed that concanavalin A bound to all three hemocyte types, while wheat germ agglutinin bound exclusively to EGs and BGs. The total hemocyte population densities within the hemolymph of all three Bathymodiolus mussel species were similar (8.4-13.3 × 10(5) cells/mL), and the percentages of circulating AGs, BGs, and EGs in the hemolymph of these organisms were 44.7-48.5%, 14.3-17.6%, and 34.3-41.0%, respectively. To analyze the functional differences between these hemocytes, the phagocytic activity and post-phagocytic phagosome-lysosome fusion events were analyzed in each cell type using a fluorescent Alexa Fluor(®) 488-conjugated Escherichia coli bioparticle and a LysoTracker(®) lysosomal marker, respectively. While the AGs exhibited no phagocytic activity, both types of granulocytes were phagocytic. Of the three hemocyte types, the EGs exhibited the highest level of phagocytic activity as well as rapid phagosome-lysosome fusion, which occurred within 2 h of incubation. Meanwhile, the BGs showed lower phagocytic activity and lower rates of phagosome-lysosome fusion than the EGs. These findings indicate that the two types of granulocyte play distinct roles in the defense system. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Microarray Bactericidal Testing of Natural Products Against Yersinia intermedia and Bacillus anthracis

DTIC Science & Technology

2002-01-01

Based Preservation Systems and Probiotic Bacteria. In Food Microbiology: Fundamentals and Frontiers. M. P. Doyle, L.R. Beuchat and T.J. Montville...Microarray Bactericidal Testing of Natural Products Against Yersinia intermedia and Bacillus anthracis I.J. Fry1, F.K. Lee2, A. Turetsky2 and J.J...effective protection against biological warfare agents (BWA’s), natural products with a historical record of bactericidal efficacy such as

Vertical and horizontal transmission of tilapia larvae encephalitis virus: the bad and the ugly.

PubMed

Sinyakov, Michael S; Belotsky, Sandro; Shlapobersky, Mark; Avtalion, Ramy R

2011-02-05

Impairment of innate immunity in tilapia larvae after vertical and horizontal infection with the newly characterized tilapia larvae encephalitis virus (TLEV) was accessed by evaluation of cell-mediated reactive oxygen species (ROS) production in affected fish with the use of horseradish peroxidase-amplified luminol-dependent chemiluminescence assay. The priming in-vivo infection with TLEV resulted in downregulation of ROS response in both vertically- and horizontally-infected fish; this suppression was further exacerbated by specific in-vitro booster infection with the same virus. Application of Ca ionophore and phorbol myristate acetate as alternative nonspecific boosters enabled restoration of ROS release in vertically-infected but not in horizontally-infected larvae. The results indicate severe TLEV-imposed phagocyte dysfunction in affected larvae. The difference in restoration potential of ROS production after vertical and horizontal virus transmission is interpreted in the frame of principal distinctions between the two modes. Copyright © 2010 Elsevier Inc. All rights reserved.

Aspergillus-induced superoxide production by cystic fibrosis phagocytes is associated with disease severity.

PubMed

Brunel, Shan F; Willment, Janet A; Brown, Gordon D; Devereux, Graham; Warris, Adilia

2018-04-01

Aspergillus fumigatus infects up to 50% of cystic fibrosis (CF) patients and may play a role in progressive lung disease. As cystic fibrosis transmembrane conductance regulator is expressed in cells of the innate immune system, we hypothesised that impaired antifungal immune responses play a role in CF-related Aspergillus lung disease. Peripheral blood mononuclear cells, polymorphonuclear cells (PMN) and monocytes were isolated from blood samples taken from CF patients and healthy volunteers. Live-cell imaging and colorimetric assays were used to assess antifungal activity in vitro . Production of reactive oxygen species (ROS) was measured using luminol-induced chemiluminescence and was related to clinical metrics as collected by case report forms. CF phagocytes are as effective as those from healthy controls with regards to phagocytosis, killing and restricting germination of A. fumigatus conidia. ROS production by CF phagocytes was up to four-fold greater than healthy controls (p<0.05). This effect could not be replicated in healthy phagocytes by priming with lipopolysaccharide or serum from CF donors. Increased production of ROS against A. fumigatus by CF PMN was associated with an increased number of clinical exacerbations in the previous year (p=0.007) and reduced lung function (by forced expiratory volume in 1 s) (p=0.014). CF phagocytes mount an intrinsic exaggerated release of ROS upon A. fumigatus stimulation which is associated with clinical disease severity.

Aspergillus-induced superoxide production by cystic fibrosis phagocytes is associated with disease severity

PubMed Central

Brunel, Shan F.; Brown, Gordon D.; Devereux, Graham; Warris, Adilia

2018-01-01

Aspergillus fumigatus infects up to 50% of cystic fibrosis (CF) patients and may play a role in progressive lung disease. As cystic fibrosis transmembrane conductance regulator is expressed in cells of the innate immune system, we hypothesised that impaired antifungal immune responses play a role in CF-related Aspergillus lung disease. Peripheral blood mononuclear cells, polymorphonuclear cells (PMN) and monocytes were isolated from blood samples taken from CF patients and healthy volunteers. Live-cell imaging and colorimetric assays were used to assess antifungal activity in vitro. Production of reactive oxygen species (ROS) was measured using luminol-induced chemiluminescence and was related to clinical metrics as collected by case report forms. CF phagocytes are as effective as those from healthy controls with regards to phagocytosis, killing and restricting germination of A. fumigatus conidia. ROS production by CF phagocytes was up to four-fold greater than healthy controls (p<0.05). This effect could not be replicated in healthy phagocytes by priming with lipopolysaccharide or serum from CF donors. Increased production of ROS against A. fumigatus by CF PMN was associated with an increased number of clinical exacerbations in the previous year (p=0.007) and reduced lung function (by forced expiratory volume in 1 s) (p=0.014). CF phagocytes mount an intrinsic exaggerated release of ROS upon A. fumigatus stimulation which is associated with clinical disease severity. PMID:29651422

Interference of Antibacterial Agents with Phagocyte Functions: Immunomodulation or “Immuno-Fairy Tales”?

PubMed Central

Labro, Marie-Thérése

2000-01-01

Professional phagocytes (polymorphonuclear neutrophils and monocytes/macrophages) are a main component of the immune system. These cells are involved in both host defenses and various pathological settings characterized by excessive inflammation. Accordingly, they are key targets for immunomodulatory drugs, among which antibacterial agents are promising candidates. The basic and historical concepts of immunomodulation will first be briefly reviewed. Phagocyte complexity will then be unravelled (at least in terms of what we know about the origin, subsets, ambivalent roles, functional capacities, and transductional pathways of this cell and how to explore them). The core subject of this review will be the many possible interactions between antibacterial agents and phagocytes, classified according to demonstrated or potential clinical relevance (e.g., neutropenia, intracellular accumulation, and modulation of bacterial virulence). A detailed review of direct in vitro effects will be provided for the various antibacterial drug families, followed by a discussion of the clinical relevance of these effects in two particular settings: immune deficiency and inflammatory diseases. The prophylactic and therapeutic use of immunomodulatory antibiotics will be considered before conclusions are drawn about the emerging (optimistic) vision of future therapeutic prospects to deal with largely unknown new diseases and new pathogens by using new agents, new techniques, and a better understanding of the phagocyte in particular and the immune system in general. PMID:11023961

NADPH Oxidase-Driven Phagocyte Recruitment Controls Candida albicans Filamentous Growth and Prevents Mortality

PubMed Central

Brothers, Kimberly M.; Gratacap, Remi L.; Barker, Sarah E.; Newman, Zachary R.; Norum, Ashley; Wheeler, Robert T.

2013-01-01

Candida albicans is a human commensal and clinically important fungal pathogen that grows as both yeast and hyphal forms during human, mouse and zebrafish infection. Reactive oxygen species (ROS) produced by NADPH oxidases play diverse roles in immunity, including their long-appreciated function as microbicidal oxidants. Here we demonstrate a non-traditional mechanistic role of NADPH oxidase in promoting phagocyte chemotaxis and intracellular containment of fungi to limit filamentous growth. We exploit the transparent zebrafish model to show that failed NADPH oxidase-dependent phagocyte recruitment to C. albicans in the first four hours post-infection permits fungi to germinate extracellularly and kill the host. We combine chemical and genetic tools with high-resolution time-lapse microscopy to implicate both phagocyte oxidase and dual-specific oxidase in recruitment, suggesting that both myeloid and non-myeloid cells promote chemotaxis. We show that early non-invasive imaging provides a robust tool for prognosis, strongly connecting effective early immune response with survival. Finally, we demonstrate a new role of a key regulator of the yeast-to-hyphal switching program in phagocyte-mediated containment, suggesting that there are species-specific methods for modulation of NADPH oxidase-independent immune responses. These novel links between ROS-driven chemotaxis and fungal dimorphism expand our view of a key host defense mechanism and have important implications for pathogenesis. PMID:24098114

Morphological bactericidal fast-acting effects of peracetic acid, a high-level disinfectant, against Staphylococcus aureus and Pseudomonas aeruginosa biofilms in tubing.

PubMed

Chino, T; Nukui, Y; Morishita, Y; Moriya, K

2017-01-01

The bactericidal effect of disinfectants against biofilms is essential to reduce potential endoscopy-related infections caused by contamination. Here, we investigated the bactericidal effect of a high-level disinfectant, peracetic acid (PAA), against Staphylococcus aureus and Pseudomonas aeruginosa biofilm models in vitro. S. aureus and P. aeruginosa biofilms were cultured at 35 °C for 7 days with catheter tubes. The following high-level disinfectants (HLDs) were tested: 0.3% PAA, 0.55% ortho-phthalaldehyde (OPA), and 2.0% alkaline-buffered glutaraldehyde (GA). Biofilms were exposed to these agents for 1-60 min and observed after 5 min and 30 min by transmission and scanning electron microscopy. A Student's t test was performed to compare the exposure time required for bactericidal effectiveness of the disinfectants. PAA and GA were active within 1 min and 5 min, respectively, against S. aureus and P. aeruginosa biofilms. OPA took longer than 10 min and 30 min to act against S. aureus and P. aeruginosa biofilms, respectively ( p  < 0.01). Treatment with PAA elicited changes in cell shape after 5 min and structural damage after 30 min. Amongst the HLDs investigated, PAA elicited the most rapid bactericidal effects against both biofilms. Additionally, treatment with PAA induced morphological alterations in the in vitro biofilm models, suggesting that PAA exerts fast-acting bactericidal effects against biofilms associated with endoscopy-related infections. These findings indicate that the exposure time for bactericidal effectiveness of HLDs for endoscope reprocessing in healthcare settings should be reconsidered.

Bactericidal Effects and Mechanism of Action of Olanexidine Gluconate, a New Antiseptic

PubMed Central

Iwata, Koushi; Nii, Takuya; Nakata, Hikaru; Tsubotani, Yoshie; Inoue, Yasuhide

2015-01-01

Olanexidine gluconate [1-(3,4-dichlorobenzyl)-5-octylbiguanide gluconate] (development code OPB-2045G) is a new monobiguanide compound with bactericidal activity. In this study, we assessed its spectrum of bactericidal activity and mechanism of action. The minimal bactericidal concentrations of the compound for 30-, 60-, and 180-s exposures were determined with the microdilution method using a neutralizer against 320 bacterial strains from culture collections and clinical isolates. Based on the results, the estimated bactericidal olanexidine concentrations with 180-s exposures were 869 μg/ml for Gram-positive cocci (155 strains), 109 μg/ml for Gram-positive bacilli (29 strains), and 434 μg/ml for Gram-negative bacteria (136 strains). Olanexidine was active against a wide range of bacteria, especially Gram-positive cocci, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci, and had a spectrum of bactericidal activity comparable to that of commercial antiseptics, such as chlorhexidine and povidone-iodine. In vitro experiments exploring its mechanism of action indicated that olanexidine (i) interacts with the bacterial surface molecules, such as lipopolysaccharide and lipoteichoic acid, (ii) disrupts the cell membranes of liposomes, which are artificial bacterial membrane models, (iii) enhances the membrane permeability of Escherichia coli, (iv) disrupts the membrane integrity of S. aureus, and (v) denatures proteins at relatively high concentrations (≥160 μg/ml). These results indicate that olanexidine probably binds to the cell membrane, disrupts membrane integrity, and its bacteriostatic and bactericidal effects are caused by irreversible leakage of intracellular components. At relatively high concentrations, olanexidine aggregates cells by denaturing proteins. This mechanism differs slightly from that of a similar biguanide compound, chlorhexidine. PMID:25987609

Genetic Analysis Reveals a Longevity-Associated Protein Modulating Endothelial Function and Angiogenesis.

PubMed

Villa, Francesco; Carrizzo, Albino; Spinelli, Chiara C; Ferrario, Anna; Malovini, Alberto; Maciąg, Anna; Damato, Antonio; Auricchio, Alberto; Spinetti, Gaia; Sangalli, Elena; Dang, Zexu; Madonna, Michele; Ambrosio, Mariateresa; Sitia, Leopoldo; Bigini, Paolo; Calì, Gaetano; Schreiber, Stefan; Perls, Thomas; Fucile, Sergio; Mulas, Francesca; Nebel, Almut; Bellazzi, Riccardo; Madeddu, Paolo; Vecchione, Carmine; Puca, Annibale A

2015-07-31

Long living individuals show delay of aging, which is characterized by the progressive loss of cardiovascular homeostasis, along with reduced endothelial nitric oxide synthase activity, endothelial dysfunction, and impairment of tissue repair after ischemic injury. Exploit genetic analysis of long living individuals to reveal master molecular regulators of physiological aging and new targets for treatment of cardiovascular disease. We show that the polymorphic variant rs2070325 (Ile229Val) in bactericidal/permeability-increasing fold-containing-family-B-member-4 (BPIFB4) associates with exceptional longevity, under a recessive genetic model, in 3 independent populations. Moreover, the expression of BPIFB4 is instrumental to maintenance of cellular and vascular homeostasis through regulation of protein synthesis. BPIFB4 phosphorylation/activation by protein-kinase-R-like endoplasmic reticulum kinase induces its complexing with 14-3-3 and heat shock protein 90, which is facilitated by the longevity-associated variant. In isolated vessels, BPIFB4 is upregulated by mechanical stress, and its knock-down inhibits endothelium-dependent vasorelaxation. In hypertensive rats and old mice, gene transfer of longevity-associated variant-BPIFB4 restores endothelial nitric oxide synthase signaling, rescues endothelial dysfunction, and reduces blood pressure levels. Furthermore, BPIFB4 is implicated in vascular repair. BPIFB4 is abundantly expressed in circulating CD34(+) cells of long living individuals, and its knock-down in endothelial progenitor cells precludes their capacity to migrate toward the chemoattractant SDF-1. In a murine model of peripheral ischemia, systemic gene therapy with longevity-associated variant-BPIFB4 promotes the recruitment of hematopoietic stem cells, reparative vascularization, and reperfusion of the ischemic muscle. Longevity-associated variant-BPIFB4 may represent a novel therapeutic tool to fight endothelial dysfunction and promote vascular reparative processes. © 2015 American Heart Association, Inc.

Development of a Novel Targeted RNAi Delivery Technology in Therapies for Metabolic Diseases

DTIC Science & Technology

2016-10-01

Kupffer cells and macrophages as demonstrated in our earlier studies, for targeted delivery of the sdRNA to these phagocytes in liver as originally...conjugation to glucan shell while preserving targeting specificity to phagocytic cells observed with our existing GeRP formulations. Small

Evaluating the Effects of Stressors on Immune Function during Simulated Dives in Marine Mammals

DTIC Science & Technology

2015-04-24

differed the most from all other exposures. In contrast, human cells tended to display either smaller decreases, or increases, in phagocytic activity...phagocytosis similar to baseline samples; decreased phagocytic activity for the dive periods of pressure exposures, with increased activity following the

[Bactericidal activity of colloidal silver against grampositive and gramnegative bacteria].

PubMed

Afonina, I A; Kraeva, L A; Tseneva, G Ia

2010-01-01

It was shown that colloidal silver solution prepared in cooperation with the A. F. Ioffe Physical Technical Institute of the Russian Academy of Sciences, had significant bactericidal activity. Stable bactericidal effect on gramnegative microorganisms was observed after their 2-hour exposition in the solution of colloidal silver at a concentration of 10 ppm. Grampositive capsule-forming microorganisms were less susceptible to the colloidal silver solution: their death was observed after the 4-hour exposition in the solution.

Approach to Cultural Asset Preservation "Enzyme Filter Media Has Bactericidal Effect and Bacteriostasis Effect in Air Phase"

NASA Astrophysics Data System (ADS)

Isomae, Kazuro

Enzyme air-filter media according to the bactericidal effect as an environmental green technology acquired the high appraisal and the result in the domestic and foreign clean room and the air conditioning field. The mechanism of this enzyme technology, safety, and the bactericidal effect in the real environment are discussed by using the electron microscopic picture etc. And it proposes to apply these technologies to the cultural asset preservation.

Modification of TiO(2) nanotube surfaces by electro-spray deposition of amoxicillin combined with PLGA for bactericidal effects at surgical implantation sites.

PubMed

Lee, Jung-Hwan; Moon, Seung-Kyun; Kim, Kwang-Mahn; Kim, Kyoung-Nam

2013-01-01

To fabricate the antibiotic-releasing coatings on TiO(2) nanotube surfaces for wide applications of implant and bone plate in medical and dental surgery, the optimal deposition time of amoxicillin/PLGA solution simultaneously performing non-toxicity and a high bactericidal effect for preventing early implant failures was found. FE-SEM, ESD and FT-IR were used for confirming deposition of amoxicillin/PLGA on the TiO(2) surface. Also, the elution of amoxicillin/PLGA in a TiO(2) nanotube surface was measured by a UV-VIS spectrophotometer. The bactericidal effect of amoxicillin on the TiO(2) nanotube surface was evaluated by using Staphylococcus aureus (S. aureus). The cytotoxicity and cell proliferation were observed by WST assay using MC3T3-E1 osteoblast cells. The results indicated that the TiO(2) nanotube surface controlled by electro-spray deposition time with amoxicillin/PLGA solution could provide a high bactericidal effect against S. aureus by the bactericidal effect of amoxicillin, as well as good osteoblast cell proliferation at the TiO(2) nanotube surface without toxicity. This study used electro-spray deposition (ESD) methodology to obtain amoxicillin deposition in nanotube structures of TiO(2) and found the optimal deposition time of amoxicillin/PLGA solution simultaneously performing non-toxicity and a high bactericidal effect for preventing early implant failures.

Bactericidal and anti-adhesive properties of culinary and medicinal plants against Helicobacter pylori.

PubMed

O'Mahony, Rachel; Al-Khtheeri, Huda; Weerasekera, Deepaka; Fernando, Neluka; Vaira, Dino; Holton, John; Basset, Christelle

2005-12-21

To investigate the bactericidal and anti-adhesive properties of 25 plants against Helicobacter pylori (H. pylori). Twenty-five plants were boiled in water to produce aqueous extracts that simulate the effect of cooking. The bactericidal activity of the extracts was assessed by a standard kill-curve with seven strains of H. pylori. The anti-adhesive property was assessed by the inhibition of binding of four strains of FITC-labeled H. pylori to stomach sections. Of all the plants tested, eight plants, including Bengal quince, nightshade, garlic, dill, black pepper, coriander, fenugreek and black tea, were found to have no bactericidal effect on any of the isolates. Columbo weed, long pepper, parsley, tarragon, nutmeg, yellow-berried nightshade, threadstem carpetweed, sage and cinnamon had bactericidal activities against H. pylori, but total inhibition of growth was not achieved in this study. Among the plants that killed H. pylori, turmeric was the most efficient, followed by cumin, ginger, chilli, borage, black caraway, oregano and liquorice. Moreover, extracts of turmeric, borage and parsley were able to inhibit the adhesion of H. pylori strains to the stomach sections. Several plants that were tested in our study had bactericidal and/or anti-adhesive effects on H. pylori. Ingestion of the plants with anti-adhesive properties could therefore provide a potent alternative therapy for H. pylori infection, which overcomes the problem of resistance associated with current antibiotic treatment.

Effectiveness of disinfectants used in cooling towers against Legionella pneumophila.

PubMed

García, M T; Pelaz, C

2008-01-01

Legionella persists in man-made aquatic installations despite preventive treatments. More information about disinfectants could improve the effectiveness of treatments. This study tests the susceptibility of Legionella pneumophila serogroup (sg) 1 against 8 disinfectants used in cooling tower treatments. We determined the minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and bactericidal effect of sodium hypochlorite (A), hydrogen peroxide with silver nitrate (B), didecyldimethylammonium chloride (C), benzalkonium chloride (D), tributyltetradecylphosphonium chloride (E), tetrahydroxymethylphosphonium sulfide (F), 2,2-dibromonitropropionamide (G) and chloromethylisothiazolone (H) against 28 L. pneumophila sg 1 isolates. MIC and MBC values were equivalent. Bacteria are less susceptible to disinfectants F, B, D and A than to H, E, C and G. All disinfectants induced a bactericidal effect. The effect rate is dose dependent for G, H, F and B; the effect is fast for the rest of disinfectants at any concentration. The bactericidal activity of disinfectants A, G and F depends on the susceptibility test used. All disinfectants have bactericidal activity against L. pneumophila sg 1 at concentrations used in cooling tower treatments. Results depend on the assay for some products.

Synthesis and Complete Antimicrobial Characterization of CEOBACTER, an Ag-Based Nanocomposite

PubMed Central

Vasquez-Peña, M.; Raymond-Herrera, O.; Villavicencio-García, H.; Petranovskii, V.; Vazquez-Duhalt, R.; Huerta-Saquero, A.

2016-01-01

The antimicrobial activity of silver nanoparticles (AgNPs) is currently used as an alternative disinfectant with diverse applications, ranging from decontamination of aquatic environments to disinfection of medical devices and instrumentation. However, incorporation of AgNPs to the environment causes collateral damage that should be avoided. In this work, a novel Ag-based nanocomposite (CEOBACTER) was successfully synthetized. It showed excellent antimicrobial properties without the spread of AgNPs into the environment. The complete CEOBACTER antimicrobial characterization protocol is presented herein. It is straightforward and reproducible and could be considered for the systematic characterization of antimicrobial nanomaterials. CEOBACTER showed minimal bactericidal concentration of 3 μg/ml, bactericidal action time of 2 hours and re-use capacity of at least five times against E. coli cultures. The bactericidal mechanism is the release of Ag ions. CEOBACTER displays potent bactericidal properties, long lifetime, high stability and re-use capacity, and it does not dissolve in the solution. These characteristics point to its potential use as a bactericidal agent for decontamination of aqueous environments. PMID:27824932

Immunity to Escherichia coli in pigs: Serum Gamma Globulin Levels, Indirect Hemagglutinating Antibody Titres and Bactericidal Activity Against E. coli in pigs up to five Weeks of Age

PubMed Central

Wilson, M. R.; Svendsen, J.

1972-01-01

Serum gamma globulin levels, indirect hemagglutinating antibody titres and bactericidal activity against the 0149:K91;K88ac:H10 Serotype of Escherichia coli were determined in pigs up to five weeks of age from vaccinated and non-vaccinated sows. Gamma globulin levels at two days of age were approximately twice adult levels, by three weeks of age they were one quarter of adult levels and remained so until five weeks of age. Indirect hemagglutinating antibody activity was highest at two days of age, fell until three weeks of age and then rose. Little or no indirect hemagglutinating antibody activity was detected in sera taken at two days of age from pigs from non-vaccinated sows. Only three of 26 two day old pigs had demonstrable bactericidal activity; by three weeks of age 16 of 26 had bactericidal activity. Serum from piglets of vaccinated sows had no more bactericidal activity than did sera from non-vaccinated sows. PMID:4110608

Immune response of greenback flounder Rhombosolea tapirina after exposure to contaminated marine sediment and diet.

PubMed

Mondon, J A; Duda, S; Nowak, B F

2000-01-01

Non-specific immune response of greenback flounder, Rhombosolea tapirina, exposed to contaminated marine sediments was examined. Reference sediments from Port Sorell and contaminated sediments from Deceitful Cove, Tasmania, Australia were investigated. Hatchery-reared flounder were exposed to reference sediment, contaminated sediment or contaminated sediment and diet for 6 weeks. Phagocytic capacity and lysozyme response in flounder were examined on cessation of exposure trial. Significant differences were found in phagocytic capacity and lysozyme response between treatments. Exposure to contaminated sediment, irrespective of diet or benthic disturbance elicited inhibition of phagocytic efficiency in flounder. Disturbance of contaminated sediment stimulated lysozyme activity. The immune response in flounder indicates potential immunotoxicity of sediment from Deceitful Cove.

Hemocytes from Pediculus humanus humanus are hosts for human bacterial pathogens

PubMed Central

Coulaud, Pierre-Julien; Lepolard, Catherine; Bechah, Yassina; Berenger, Jean-Michel; Raoult, Didier; Ghigo, Eric

2015-01-01

Pediculus humanus humanus is an human ectoparasite which represents a serious public health threat because it is vector for pathogenic bacteria. It is important to understand and identify where bacteria reside in human body lice to define new strategies to counterstroke the capacity of vectorization of the bacterial pathogens by body lice. It is known that phagocytes from vertebrates can be hosts or reservoirs for several microbes. Therefore, we wondered if Pediculus humanus humanus phagocytes could hide pathogens. In this study, we characterized the phagocytes from Pediculus humanus humanus and evaluated their contribution as hosts for human pathogens such as Rickettsia prowazekii, Bartonella Quintana, and Acinetobacter baumannii. PMID:25688336

Enhancement in ex vivo phagocytic capacity of peritoneal leukocytes in mice by oral delivery of various lactic-acid-producing bacteria.

PubMed

Lee, Yeonhee; Lee, Taik-Soo

2005-01-01

Lactic-acid-producing bacteria (LABs) are known to have immunomodulating activity. In the current study, various LABs were tested for their immunity-enhancing activity, especially the phagocytic activity of leukocytes. Viable but not heat-killed cells of Weissella kimchii strain PL9001, Lactobacillus fermentum strain PL9005, and L. plantarum strain PL9011 significantly increased the ex vivo phagocytic capacity of mouse peritoneal leukocytes to ingest fluorescein isothiocyanate (FITC)-labeled Escherichia coli in a strain-dependent manner. Results of this and previous studies suggest these LABs as candidates for new probiotics. This is the first report of the enhancement of peritoneal leukocyte activity of these species.

Fungi and bacteria. [fungicide and bactericide measures for spacecraft in tropical regions

NASA Technical Reports Server (NTRS)

Daniels, G. E.

1973-01-01

Spacecraft equipment is usually protected from fungi and bacteria by incorporating a fungicide-bactericide in the material, by a fungicide-bactericide spray, or by reducing the relative humidity to a degree where growth will not take place. A unique method to protect delicate, expensive bearings in equipment was to maintain a pressure (with dry air or nitrogen) slightly above the outside atmosphere (few millibars) within the working parts of the equipment, thus preventing fungi from entering equipment.

In Vitro Antibacterial Activities of AF 3013, the Active Metabolite of Prulifloxacin, against Nosocomial and Community Italian Isolates

PubMed Central

Montanari, Maria Pia; Mingoia, Marina; Varaldo, Pietro Emanuele

2001-01-01

AF 3013, the active metabolite of prulifloxacin, was tested to determine its inhibitory and bactericidal activities against 396 nosocomial and 258 community Italian isolates. Compared with that of ciprofloxacin, its activity (assessed in MIC and minimal bactericidal concentration tests) was generally similar or greater against gram-positive bacteria and greater against gram-negative bacteria. In time-kill assays using selected isolates, its bactericidal activity was comparable to that of ciprofloxacin. PMID:11709353

Monoclonal antibodies to meningococcal factor H binding protein with overlapping epitopes and discordant functional activity.

PubMed

Giuntini, Serena; Beernink, Peter T; Reason, Donald C; Granoff, Dan M

2012-01-01

Meningococcal factor H binding protein (fHbp) is a promising vaccine candidate. Anti-fHbp antibodies can bind to meningococci and elicit complement-mediated bactericidal activity directly. The antibodies also can block binding of the human complement down-regulator, factor H (fH). Without bound fH, the organism would be expected to have increased susceptibility to bacteriolysis. Here we describe bactericidal activity of two anti-fHbp mAbs with overlapping epitopes in relation to their different effects on fH binding and bactericidal activity. Both mAbs recognized prevalent fHbp sequence variants in variant group 1. Using yeast display and site-specific mutagenesis, binding of one of the mAbs (JAR 1, IgG3) to fHbp was eliminated by a single amino acid substitution, R204A, and was decreased by K143A but not by R204H or D142A. The JAR 1 epitope overlapped that of previously described mAb (mAb502, IgG2a) whose binding to fHbp was eliminated by R204A or R204H substitutions, and was decreased by D142A but not by K143A. Although JAR 1 and mAb502 appeared to have overlapping epitopes, only JAR 1 inhibited binding of fH to fHbp and had human complement-mediated bactericidal activity. mAb502 enhanced fH binding and lacked human complement-mediated bactericidal activity. To control for confounding effects of different mouse IgG subclasses on complement activation, we created chimeric mAbs in which the mouse mAb502 or JAR 1 paratopes were paired with human IgG1 constant regions. While both chimeric mAbs showed similar binding to fHbp, only JAR 1, which inhibited fH binding, had human complement-mediated bactericidal activity. The lack of human complement-mediated bactericidal activity by anti-fHbp mAb502 appeared to result from an inability to inhibit binding of fH. These results underscore the importance of inhibition of fH binding for anti-fHbp mAb bactericidal activity.

High-dose catecholamine treatment decreases polymorphonuclear leukocyte phagocytic capacity and reactive oxygen production.

PubMed Central

Wenisch, C; Parschalk, B; Weiss, A; Zedwitz-Liebenstein, K; Hahsler, B; Wenisch, H; Georgopoulos, A; Graninger, W

1996-01-01

Flow cytometry was used to study phagocytic function (uptake of fluorescein isothiocyanate-labeled bacteria) and release of reactive oxygen products (dihydrorhodamine 123 converted to rhodamine 123) following phagocytosis by neutrophil granulocytes of heparinized whole blood treated with adrenaline, noradrenaline, dopamine, dobutamine, or orciprenaline. Reduced neutrophil phagocytosis and reactive oxygen production were seen at 12 micrograms of adrenaline per liter (72% each compared with control values); at 120 micrograms of noradrenaline (72% each), dobutamine (83 and 80%, respectively), and orciprenaline (81 and 80%, respectively) per liter; and at 100 micrograms of dopamine per liter (66 and 70%) (P < 0.05 for all). At these dosages, neutrophil chemotaxis was reduced to < 50% of control values for all catecholamines. Treatment with catecholamines at lower dosages had no significant effect on phagocytosis or generation of reactive oxygen products or chemotaxis. The phagocytic capacity of granulocytes was related to the generation of reactive oxygen products (r = 0.789; P < 0.05). The results demonstrate that catecholamines have a suppressive effect on the response of phagocytic cells to bacterial pathogens at high therapeutic levels in blood. PMID:8807207

The Neutrophil’s Choice: Phagocytose vs Make Neutrophil Extracellular Traps

PubMed Central

Manfredi, Angelo A.; Ramirez, Giuseppe A.; Rovere-Querini, Patrizia; Maugeri, Norma

2018-01-01

Neutrophils recognize particulate substrates of microbial or endogenous origin and react by sequestering the cargo via phagocytosis or by releasing neutrophil extracellular traps (NETs) outside the cell, thus modifying and alerting the environment and bystander leukocytes. The signals that determine the choice between phagocytosis and the generation of NETs are still poorly characterized. Neutrophils that had phagocytosed bulky particulate substrates, such as apoptotic cells and activated platelets, appear to be “poised” in an unresponsive state. Environmental conditions, the metabolic, adhesive and activation state of the phagocyte, and the size of and signals associated with the tethered phagocytic cargo influence the choice of the neutrophils, prompting either phagocytic clearance or the generation of NETs. The choice is dichotomic and apparently irreversible. Defects in phagocytosis may foster the intravascular generation of NETs, thus promoting vascular inflammation and morbidities associated with diseases characterized by defective phagocytic clearance, such as systemic lupus erythematosus. There is a strong potential for novel treatments based on new knowledge of the events determining the inflammatory and pro-thrombotic function of inflammatory leukocytes. PMID:29515586

Immunomodulatory effect of prolactin on Atlantic salmon (Salmo salar) macrophage function.

PubMed

Paredes, Marco; Gonzalez, Katerina; Figueroa, Jaime; Montiel-Eulefi, Enrique

2013-10-01

The in vitro and in vivo effect of prolactin (PRL) on kidney macrophages from Atlantic salmon (Salmo salar) was investigated under the assumption that PRL stimulates immune innate response in mammals. Kidney macrophages were treated two ways: first, cultured in RPMI 1640 medium containing 10, 25, 50 and 100 ng/mL of PRL and second, isolated from a fish with a PRL-injected dose of 100 ng/Kg. Reduced nitro blue tetrazolium (formazan) was used to produce intracellular superoxide anion. Phagocytic activity of PRL was determined in treated cells by optical microscopy observation of phagocytized Congo red-stained yeast. Kidney lysozyme activity was measured in PRL-injected fish. In vitro and in vivo macrophages treated with PRL presented an enhanced superoxide anion production, elevated phagocytic index and increased phagocytic activity. Treated fish showed higher levels of lysozyme activity in the head kidney compared to the control. These results indicate that PRL-stimulated innate immune response in Atlantic salmon and future studies will allow us to assess the possibility of using PRL as an immunostimulant in the Chilean salmon industry.

The Lipopolysaccharide of Brucella abortus BvrS/BvrR Mutants Contains Lipid A Modifications and Has Higher Affinity for Bactericidal Cationic Peptides

PubMed Central

Manterola, Lorea; Moriyón, Ignacio; Moreno, Edgardo; Sola-Landa, Alberto; Weiss, David S.; Koch, Michel H. J.; Howe, Jörg; Brandenburg, Klaus; López-Goñi, Ignacio

2005-01-01

The two-component BvrS/BvrR system is essential for Brucella abortus virulence. It was shown previously that its dysfunction abrogates expression of some major outer membrane proteins and increases bactericidal peptide sensitivity. Here, we report that BvrS/BvrR mutants have increased surface hydrophobicity and susceptibility to killing by nonimmune serum. The bvrS and bvrR mutant lipopolysaccharides (LPSs) bound more polymyxin B, chimeras constructed with bvrS mutant cells and parental LPS showed augmented polymyxin B resistance, and, conversely, parental cells and bvrS mutant LPS chimeras were more sensitive and displayed polymyxin B-characteristic outer membrane lesions, implicating LPS as being responsible for the phenotype of the BvrS/BvrR mutants. No qualitative or quantitative changes were detected in other envelope and outer membrane components examined: periplasmic β(1-2) glucans, native hapten polysaccharide, and phospholipids. The LPS of the mutants was similar to parental LPS in O-polysaccharide polymerization and fine structure but showed both increased underacylated lipid A species and higher acyl-chain fluidity that correlated with polymyxin B binding. These lipid A changes did not alter LPS cytokine induction, showing that in contrast to other gram-negative pathogens, recognition by innate immune receptors is not decreased by these changes in LPS structure. Transcription of Brucella genes required for incorporating long acyl chains into lipid A (acpXL and lpxXL) or implicated in lipid A acylation control (bacA) was not affected. We propose that in Brucella the outer membrane homeostasis depends on the functioning of BvrS/BvrR. Accordingly, disruption of BvrS/BvrR damages the outer membrane, thus contributing to the severe attenuation manifested by bvrS and bvrR mutants. PMID:16077108

The effect of core and lanthanide ion dopants in sodium fluoride-based nanocrystals on phagocytic activity of human blood leukocytes

NASA Astrophysics Data System (ADS)

Sojka, Bartlomiej; Liskova, Aurelia; Kuricova, Miroslava; Banski, Mateusz; Misiewicz, Jan; Dusinska, Maria; Horvathova, Mira; Ilavska, Silvia; Szabova, Michaela; Rollerova, Eva; Podhorodecki, Artur; Tulinska, Jana

2017-02-01

Sodium fluoride-based β-NaLnF4 nanoparticles (NPs) doped with lanthanide ions are promising materials for application as luminescent markers in bio-imaging. In this work, the effect of NPs doped with yttrium (Y), gadolinium (Gd), europium (Eu), thulium (Tm), ytterbium (Yb) and terbium (Tb) ions on phagocytic activity of monocytes and granulocytes and the respiratory burst was examined. The surface functionalization of <10-nm NPs was performed according to our variation of patent pending ligand exchange method that resulted in meso-2,3-dimercaptosuccinic acid (DMSA) molecules on their surface. Y-core-based NCs were doped with Eu ions, which enabled them to be excited with UV light wavelengths. Cultures of human peripheral blood ( n = 8) were in vitro treated with five different concentrations of eight NPs for 24 h. In summary, neither type of nanoparticles is found toxic with respect to conducted test; however, some cause toxic effects (they have statistically significant deviations compared to reference) in some selected doses tested. Both core types of NPs (Y-core and Gd-core) impaired the phagocytic activity of monocytes the strongest, having minimal or none whatsoever influence on granulocytes and respiratory burst of phagocytic cells. The lowest toxicity was observed in Gd-core, Yb, Tm dopants and near-infrared nanoparticles. Clear dose-dependent effect of NPs on phagocytic activity of leukocytes and respiratory burst of cells was observed for limited number of samples.

Value of phagocyte function screening for immunotoxicity of nanoparticles in vivo.

PubMed

Fröhlich, Eleonore

2015-01-01

Nanoparticles (NPs) present in the environment and in consumer products can cause immunotoxic effects. The immune system is very complex, and in vivo studies are the gold standard for evaluation. Due to the increased amount of NPs that are being developed, cellular screening assays to decrease the amount of NPs that have to be tested in vivo are highly needed. Effects on the unspecific immune system, such as effects on phagocytes, might be suitable for screening for immunotoxicity because these cells mediate unspecific and specific immune responses. They are present at epithelial barriers, in the blood, and in almost all organs. This review summarizes the effects of carbon, metal, and metal oxide NPs used in consumer and medical applications (gold, silver, titanium dioxide, silica dioxide, zinc oxide, and carbon nanotubes) and polystyrene NPs on the immune system. Effects in animal exposures through different routes are compared to the effects on isolated phagocytes. In addition, general problems in the testing of NPs, such as unknown exposure doses, as well as interference with assays are mentioned. NPs appear to induce a specific immunotoxic pattern consisting of the induction of inflammation in normal animals and aggravation of pathologies in disease models. The evaluation of particle action on several phagocyte functions in vitro may provide an indication on the potency of the particles to induce immunotoxicity in vivo. In combination with information on realistic exposure levels, in vitro studies on phagocytes may provide useful information on the health risks of NPs.

Value of phagocyte function screening for immunotoxicity of nanoparticles in vivo

PubMed Central

Fröhlich, Eleonore

2015-01-01

Nanoparticles (NPs) present in the environment and in consumer products can cause immunotoxic effects. The immune system is very complex, and in vivo studies are the gold standard for evaluation. Due to the increased amount of NPs that are being developed, cellular screening assays to decrease the amount of NPs that have to be tested in vivo are highly needed. Effects on the unspecific immune system, such as effects on phagocytes, might be suitable for screening for immunotoxicity because these cells mediate unspecific and specific immune responses. They are present at epithelial barriers, in the blood, and in almost all organs. This review summarizes the effects of carbon, metal, and metal oxide NPs used in consumer and medical applications (gold, silver, titanium dioxide, silica dioxide, zinc oxide, and carbon nanotubes) and polystyrene NPs on the immune system. Effects in animal exposures through different routes are compared to the effects on isolated phagocytes. In addition, general problems in the testing of NPs, such as unknown exposure doses, as well as interference with assays are mentioned. NPs appear to induce a specific immunotoxic pattern consisting of the induction of inflammation in normal animals and aggravation of pathologies in disease models. The evaluation of particle action on several phagocyte functions in vitro may provide an indication on the potency of the particles to induce immunotoxicity in vivo. In combination with information on realistic exposure levels, in vitro studies on phagocytes may provide useful information on the health risks of NPs. PMID:26060398

High vancomycin MICs within the susceptible range in Staphylococcus aureus bacteraemia isolates are associated with increased cell wall thickness and reduced intracellular killing by human phagocytes.

PubMed

Falcón, Rocío; Martínez, Alba; Albert, Eliseo; Madrid, Silvia; Oltra, Rosa; Giménez, Estela; Soriano, Mario; Vinuesa, Víctor; Gozalbo, Daniel; Gil, María Luisa; Navarro, David

2016-05-01

Vancomycin minimum inhibitory concentrations (MICs) at the upper end of the susceptible range for Staphylococcus aureus have been associated with poor clinical outcomes of bloodstream infections. We tested the hypothesis that high vancomycin MICs in S. aureus bacteraemia isolates are associated with increased cell wall thickness and suboptimal bacterial internalisation or lysis by human phagocytes. In total, 95 isolates were evaluated. Original vancomycin MICs were determined by Etest. The susceptibility of S. aureus isolates to killing by phagocytes was assessed in a human whole blood assay. Internalisation of bacterial cells by phagocytes was investigated by flow cytometry. Cell wall thickness was evaluated by transmission electron microscopy. Genotypic analysis of S. aureus isolates was performed using a DNA microarray system. Vancomycin MICs were significantly higher (P=0.006) in isolates that were killed suboptimally (killing index <60%) compared with those killed efficiently (killing index >70%) and tended to correlate inversely (P=0.08) with the killing indices. Isolates in both killing groups were internalised by human neutrophils and monocytes with comparable efficiency. The cell wall was significantly thicker (P=0.03) in isolates in the low killing group. No genotypic differences were found between the isolates in both killing groups. In summary, high vancomycin MICs in S. aureus bacteraemia isolates were associated with increased cell wall thickness and reduced intracellular killing by phagocytes. Copyright © 2016 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Influences of Chlorella vulgaris dietary supplementation on growth performance, hematology, immune response and disease resistance in Oreochromis niloticus exposed to sub-lethal concentrations of penoxsulam herbicide.

PubMed

Galal, Azza A A; Reda, Rasha M; Abdel-Rahman Mohamed, Amany

2018-06-01

Little is known regarding the impact of penoxsulam, a fluorinated benzenesulfonamid rice herbicide, on Oreochromis niloticus (O. niloticus). Therefore, the current study was undertaken to highlight the effects of penoxsulam exposure on O. niloticus and to evaluate the advantages of Chlorella vulgaris (CV) dietary supplementation against the induced effects. The 96-h lethal concentration 50 (LC 50 ) penoxsulam value for O. niloticus was estimated at 8.948 mg/L by probit analysis in a static bioassay experiment. Next, 360 healthy fish were randomly allocated into 6 treatment groups. The T1 group served as the negative control and was fed a basal diet. The T2 group served as the positive control and was fed a basal diet supplemented with 10% CV. The fish in the T3 and T4 groups were exposed to 1/10 the 96-h LC 50 of penoxsulam (0.8948 mg/L) and were fed the basal diet alone or the basal diet supplemented with 10% CV, respectively. The fish in the T5 and T6 groups were exposed to 1/5 the 96-h LC 50 of penoxsulam (1.7896 mg/L) and fed the basal diet alone or the basal diet supplemented with 10% CV, respectively. Sub-acute penoxsulam exposure significantly altered hematological indices, as well as compromised the fish's immune defense mechanisms, including the phagocytic percentage, phagocytic index, nitric oxide production, immunoglobulin M levels and lysozyme, anti-trypsin and bactericidal activities subsequently decreasing O. niloticus's resistance to the Aeromonus sobria challenge and increasing disease symptoms and the mortality rate. Furthermore, sub-chronic penoxsulam exposure markedly altered growth performance, oxidant/antioxidant status and liver status and down-regulated the expression of interleukin-1β (IL-1β) and tumor necrosis-α (TNF-α). Interestingly, incorporating 10% CV into the diet protects fish against sub-acute penoxsulam-induced immunotoxicity via improvement of immune responses that increases the resistance against bacterial infection. Further, it improved the growth performance, oxidant/antioxidant status, liver status and markedly up-regulated immune-related gene expression, IL-1β and TNF-α, in the spleens of fish sub-chronically exposed to penoxsulam. These outcomes showed that dietary CV supplementation can protect the commercially valuable freshwater fish O. niloticus against penoxsulam toxicity and may be a potential feed supplement for Nile tilapia in aquaculture. Copyright © 2018 Elsevier Ltd. All rights reserved.

CRISPR-Mediated Knockout of Cybb in NSG Mice Establishes a Model of Chronic Granulomatous Disease for Human Stem-Cell Gene Therapy Transplants.

PubMed

Sweeney, Colin L; Choi, Uimook; Liu, Chengyu; Koontz, Sherry; Ha, Seung-Kwon; Malech, Harry L

2017-07-01

Chronic granulomatous disease (CGD) is characterized by defects in the production of microbicidal reactive oxygen species (ROS) by phagocytes. Testing of gene and cell therapies for the treatment of CGD in human hematopoietic cells requires preclinical transplant models. The use of the lymphocyte-deficient NOD.Cg-Prkdc scid Il2rg tm1Wjl/ SzJ (NSG) mouse strain for human hematopoietic cell xenografts to test CGD therapies is complicated by the presence of functional mouse granulocytes capable of producing ROS for subsequent bacterial and fungal killing. To establish a phagocyte-defective mouse model of X-linked CGD (X-CGD) in NSG mice, clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 was utilized for targeted knockout of mouse Cybb on the X-chromosome by microinjection of NSG mouse zygotes with Cas9 mRNA and CRISPR single-guide RNA targeting Cybb exon 1 or exon 3. This resulted in a high incidence of indel formation at the CRISPR target site, with all mice exhibiting deletions in at least one Cybb allele based on sequence analysis of tail snip DNA. A female mouse heterozygous for a 235-bp deletion in Cybb exon 1 was bred to an NSG male to establish the X-CGD NSG mouse strain, NSG.Cybb[KO]. Resulting male offspring with the 235 bp deletion were found to be defective for production of ROS by neutrophils and other phagocytes, and demonstrated increased susceptibility to spontaneous bacterial and fungal infections with granulomatous inflammation. The establishment of the phagocyte-defective NSG.Cybb[KO] mouse model enables the in vivo assessment of gene and cell therapy strategies for treating CGD in human hematopoietic cell transplants without obfuscation by functional mouse phagocytes, and may also be useful for modeling other phagocyte disorders in humanized NSG mouse xenografts.

Development of a fluorescence-based in vivo phagocytosis assay to measure mononuclear phagocyte system function in the rat.

PubMed

Tartaro, Karrie; VanVolkenburg, Maria; Wilkie, Dean; Coskran, Timothy M; Kreeger, John M; Kawabata, Thomas T; Casinghino, Sandra

2015-01-01

The mononuclear phagocyte system (MPS) which provides protection against infection is made up of phagocytic cells that engulf and digest bacteria or other foreign substances. Suppression of the MPS may lead to decreased clearance of pathogenic microbes. Drug delivery systems and immunomodulatory therapeutics that target phagocytes have a potential to inhibit MPS function. Available methods to measure inhibition of MPS function use uptake of radioactively-labeled cells or labor-intensive semi-quantitative histologic techniques. The objective of this work was to develop a non-radioactive quantitative method to measure MPS function in vivo by administering heat-killed E. coli conjugated to a pH-sensitive fluorescent dye (Bioparticles(®)). Fluorescence of the Bioparticles(®) is increased at low pH when they are in phagocytic lysosomes. The amount of Bioparticles(®) phagocytosed by MPS organs in rats was determined by measuring fluorescence intensity in livers and spleens ex vivo using an IVIS(®) Spectrum Pre-clinical In Vivo Imaging System. Phagocytosis of the particles by peripheral blood neutrophils was measured by flow cytometry. To assess method sensitivity, compounds likely to suppress the MPS [clodronate-containing liposomes, carboxylate-modified latex particles, maleic vinyl ether (MVE) polymer] were administered to rats prior to injection of the Bioparticles(®). The E. coli particles consistently co-localized with macrophage markers in the liver but not in the spleen. All of the compounds tested decreased phagocytosis in the liver, but had no consistent effects on phagocytic activity in the spleen. In addition, administration of clodronate liposomes and MVE polymer increased the percentage of peripheral blood neutrophils that phagocytosed the Bioparticles(®). In conclusion, an in vivo rat model was developed that measures phagocytosis of E. coli particles in the liver and may be used to assess the impact of test compounds on MPS function. Still, the detection of inhibition of splenic macrophage function will require further assay development.

Characterization of C-type lectins reveals an unexpectedly limited interaction between Cryptococcus neoformans spores and Dectin-1

PubMed Central

Walsh, Naomi M.; Wuthrich, Marcel; Wang, Huafeng; Klein, Bruce; Hull, Christina M.

2017-01-01

Phagocytosis by innate immune cells is an important process for protection against multiple pathologies and is particularly important for resistance to infection. However, phagocytosis has also been implicated in the progression of some diseases, including the dissemination of the human fungal pathogen, Cryptococcus neoformans. Previously, we identified Dectin-1 as a likely phagocytic receptor for C. neoformans spores through the use of soluble components in receptor-ligand blocking experiments. In this study, we used gain-of-function and loss-of-function assays with intact cells to evaluate the in vivo role of Dectin-1 and other C-type lectins in interactions with C. neoformans spores and discovered stark differences in outcome when compared with previous assays. First, we found that non-phagocytic cells expressing Dectin-1 were unable to bind spores and that highly sensitive reporter cells expressing Dectin-1 were not stimulated by spores. Second, we determined that some phagocytes from Dectin-1-/- mice interacted with spores differently than wild type (WT) cells, but the effects varied among assays and were modest overall. Third, while we detected small but statistically significant reductions in phagocytosis by primary alveolar macrophages from Dectin-1-/- mice compared to WT, we found no differences in survival between WT and Dectin-1-/- mice challenged with spores. Further analyses to assess the roles of other C-type lectins and their adapters revealed very weak stimulation of Dectin-2 reporter cells by spores and modest differences in binding and phagocytosis by Dectin-2-/- bone marrow-derived phagocytes. There were no discernable defects in binding or phagocytosis by phagocytes lacking Mannose Receptor, Mincle, Card-9, or FcRγ. Taken together, these results lead to the conclusion that Dectin-1 and other C-type lectins do not individually play a major roles in phagocytosis and innate defense by phagocytes against C. neoformans spores and highlight challenges in using soluble receptor/ligand blocking experiments to recapitulate biologically relevant interactions. PMID:28282442

The Peyer’s Patch Mononuclear Phagocyte System at Steady State and during Infection

PubMed Central

Da Silva, Clément; Wagner, Camille; Bonnardel, Johnny; Gorvel, Jean-Pierre; Lelouard, Hugues

2017-01-01

The gut represents a potential entry site for a wide range of pathogens including protozoa, bacteria, viruses, or fungi. Consequently, it is protected by one of the largest and most diversified population of immune cells of the body. Its surveillance requires the constant sampling of its encounters by dedicated sentinels composed of follicles and their associated epithelium located in specialized area. In the small intestine, Peyer’s patches (PPs) are the most important of these mucosal immune response inductive sites. Through several mechanisms including transcytosis by specialized epithelial cells called M-cells, access to the gut lumen is facilitated in PPs. Although antigen sampling is critical to the initiation of the mucosal immune response, pathogens have evolved strategies to take advantage of this permissive gateway to enter the host and disseminate. It is, therefore, critical to decipher the mechanisms that underlie both host defense and pathogen subversive strategies in order to develop new mucosal-based therapeutic approaches. Whereas penetration of pathogens through M cells has been well described, their fate once they have reached the subepithelial dome (SED) remains less well understood. Nevertheless, it is clear that the mononuclear phagocyte system (MPS) plays a critical role in handling these pathogens. MPS members, including both dendritic cells and macrophages, are indeed strongly enriched in the SED, interact with M cells, and are necessary for antigen presentation to immune effector cells. This review focuses on recent advances, which have allowed distinguishing the different PP mononuclear phagocyte subsets. It gives an overview of their diversity, specificity, location, and functions. Interaction of PP phagocytes with the microbiota and the follicle-associated epithelium as well as PP infection studies are described in the light of these new criteria of PP phagocyte identification. Finally, known alterations affecting the different phagocyte subsets during PP stimulation or infection are discussed. PMID:29038658

Understanding bactericidal performance on ambient light activated TiO2-InVO4 nanostructured films.

PubMed

He, Ziming; Xu, Qingchi; Tan, Timothy Thatt Yang

2011-12-01

TiO(2)-InVO(4) nanostructured films were coated onto glass substrates and systematically investigated for their bactericidal activities using Escherichia coli (E. coli) as the model bacterium under ambient light illumination. The uniform TiO(2)-InVO(4) nanostructured films were prepared using titanium isopropoxide (TTIP) as the precursor via a simple sol-gel approach. Polyethylenimine (PEI) was used as a surfactant to ensure uniform dispersion of InVO(4) and a sacrificial pore-inducing agent, generating nanostructured films. Compared to unmodified TiO(2) film, the current TiO(2)-InVO(4) films exhibited enhanced bactericidal activities under ambient light illumination. Bacterial cell "photo-fixation" was demonstrated to be crucial in enhancing the bactericidal activity. A bacterial-nanostructured surface interaction mechanism was proposed for the current ambient-light activated nanostructured film.

The bactericidal effect of surface micro-discharge plasma under different ambient conditions

NASA Astrophysics Data System (ADS)

Shimizu, T.; Zimmermann, J. L.; Morfill, G. E.

2011-02-01

A series of experiments on the bactericidal properties of plasmas using a surface micro-discharge (SMD) device in an atmosphere under different ambient temperatures and humidities was carried out. This plasma dispenser was developed for use as a disinfection system in private and public places (hospitals, medical practices, etc). The bactericidal effect is due to the interplay of the plasma and the chemical products produced via interactions with O2/N2 and H2O vapour in air. To use this device in different countries and therefore under various ambient conditions, it is important to understand its behaviour and efficiency, especially with respect to air temperature and humidity. The experimental results obtained in this study show that the bactericidal properties of the SMD plasma dispenser are not sensitive to the different temperatures and humidities.

Synergistic bactericidal activity of chlorhexidine-loaded, silver-decorated mesoporous silica nanoparticles.

PubMed

Lu, Meng-Meng; Wang, Qiu-Jing; Chang, Zhi-Min; Wang, Zheng; Zheng, Xiao; Shao, Dan; Dong, Wen-Fei; Zhou, Yan-Min

2017-01-01

Combination of chlorhexidine (CHX) and silver ions could engender synergistic bactericidal effect and improve the bactericidal efficacy. It is highly desired to develop an efficient carrier for the antiseptics codelivery targeting infection foci with acidic microenvironment. In this work, monodisperse mesoporous silica nanoparticle (MSN) nanospheres were successfully developed as an ideal carrier for CHX and nanosilver codelivery through a facile and environmentally friendly method. The CHX-loaded, silver-decorated mesoporous silica nanoparticles (Ag-MSNs@CHX) exhibited a pH-responsive release manner of CHX and silver ions simultaneously, leading to synergistically antibacterial effect against both gram-positive Staphylococcus aureus and gram-negative Escherichia coli . Moreover, the effective antibacterial concentration of Ag-MSNs@CHX showed less cytotoxicity on normal cells. Given their synergistically bactericidal ability and good biocompatibility, these nanoantiseptics might have effective and broad clinical applications for bacterial infections.

Interactions Between Macrophages of Guinea Pigs and Salmonellae III. Bactericidal Action and Cytophilic Antibodies of Macrophages of Infected Guinea Pigs

PubMed Central

Hsu, H. S.; Mayo, Donald R.

1973-01-01

The fate of virulent Salmonella typhimurium within macrophages of guinea pigs was assessed by a suspended cell culture procedure. The present study confirmed that macrophages of normal guinea pigs were capable of inactivating the ingested salmonellae. Macrophages of previously infected guinea pigs were not endowed with any significant increase in their ability to eliminate the ingested pathogen. However, the immune macrophages were observed to clump together tightly when they were exposed to salmonellae. This phenomenon was attributed to the presence of specific cytophilic antibodies on the immune macrophages. When immune macrophages were inactivated with Merthiolate, they agglutinated with both the H and the O antigens of S. typhimurium, but not with the O antigens of other species of Salmonella nor with the O antigens of Escherichia coli. Cytophilic antibodies could be eluted from immune macrophages by incubation in the absence of immune serum. Conversely, cytophilic antibodies could be passively transferred onto normal macrophages by incubation in the presence of immune serum. Furthermore, using immune serum previously adsorbed with the O antigens of S. typhimurium, cytophilic antibodies against the H antigens alone could be transferred onto normal macrophages, or those against the O antigens alone could be eluted from immune macrophages. These data suggest that immune macrophages possess specific cytophilic antibodies against both the H and the O antigens of S. typhimurium. It is proposed that the presence of cytophilic antibodies on immune macrophages represents an expression of antibacterial cellular immunity by enhanced clumping and phagocytic activities of the macrophages. PMID:4579899

A Bioprocessed Polysaccharide from Lentinus edodes Mycelia Cultures with Turmeric Protects Chicks from a Lethal Challenge of Salmonella Gallinarum.

PubMed

Han, Dalmuri; Lee, Hyung Tae; Lee, June Bong; Kim, Yongbaek; Lee, Sang Jong; Yoon, Jang Won

2017-02-01

Our previous studies demonstrated that a bioprocessed polysaccharide (BPP) isolated from Lentinus edodes mushroom mycelia cultures supplemented with black rice bran can protect mice against Salmonella lipopolysaccharide-induced endotoxemia and reduce the mortality from Salmonella Typhimurium infection through upregulated T-helper 1 immunity. Here, we report that a BPP from L. edodes mushroom mycelia liquid cultures supplemented with turmeric (referred to as BPP-turmeric) alters chicken macrophage responses against avian-adapted Salmonella Gallinarum and protects chicks against a lethal challenge from Salmonella Gallinarum. In vitro analyses revealed that the water extract of BPP-turmeric (i) changed the protein expression or secretion profile of Salmonella Gallinarum, although it was not bactericidal, (ii) reduced the phagocytic activity of the chicken-derived macrophage cell line HD-11 when infected with Salmonella Gallinarum, and (iii) significantly activated the transcription expression of interleukin (IL)-1β, IL-10, tumor necrosis factor α, and inducible nitric oxide synthase in response to various Salmonella infections, whereas it repressed that of IL-4, IL-6, interferon-β, and interferon-γ. We also found that BPP-turmeric (0.1 g/kg of feed) as a feed additive provided significant protection to 1-day-old chicks infected with a lethal dose of Salmonella Gallinarum. Collectively, these results imply that BPP-turmeric contains biologically active component(s) that protect chicks against Salmonella Gallinarum infection, possibly by regulating macrophage immune responses. Further studies are needed to evaluate the potential efficacy of BPP-turmeric as a livestock feed additive for the preharvest control of fowl typhoid or foodborne salmonellosis.

The activity of several newer antimicrobials against logarithmically multiplying M. leprae in mice.

PubMed

Burgos, Jasmin; de la Cruz, Eduardo; Paredes, Rose; Andaya, Cora Revelyn; Gelber, Robert H

2011-09-01

Moxifloxacin, rifampicin, rifapentine, linezolid, and PA 824, alone and in combination, have been previously administered, as single doses and five times daily doses, to M. leprae infected mice during lag phase multiplication and were each found to have some bactericidal activity. The fluroquinolones, ofloxacin, moxifloxacin and gatifloxacin, (50 mg/kg, 150 mg/kg and 300 mg/kg) and the rifamycins (5 mg/kg, 10 mg/kg, and 20 mg/kg), rifampicin and rifapentine, were evaluated alone and in combination for bactericidal activity against M. leprae using the mouse footpad model during logarithmic multiplication. Linezolid and PA 824 were similarly evaluated alone and linezolid in combination with rifampicin, minocycline and ofloxacin. The three fluroquinolones and rifamycins were found alone and in combination to be bactericidal at all dosage schedules. PA 824 had no activity against M. leprae, while linezolid at a dose of 25 mg/kg was bacteriostatic, and progressively more bactericidal at doses of 50 mg/kg and 100 mg/kg. No antagonisms were detected between any of these drugs when used in combinations. Moxifloxacin, gatifloxacin, rifapentine and linezolid were found bactericidal against rapidly multiplying M. leprae.

In vitro activities of ciprofloxacin and rifampin alone and in combination against growing and nongrowing strains of methicillin-susceptible and methicillin-resistant Staphylococcus aureus.

PubMed Central

Bahl, D; Miller, D A; Leviton, I; Gialanella, P; Wolin, M J; Liu, W; Perkins, R; Miller, M H

1997-01-01

We characterized the effects of ciprofloxacin and rifampin alone and in combination on Staphylococcus aureus in vitro. The effects of drug combinations (e.g., indifferent, antagonistic, or additive interactions) on growth inhibition were compared by disk approximation studies and by determining the fractional inhibitory concentrations. Bactericidal effects in log-phase bacteria and in nongrowing isolates were characterized by time-kill methods. The effect of drug combinations was dependent upon whether or not cells were growing and whether killing or growth inhibition was the endpoint used to measure drug interaction. Despite bactericidal antagonism in time-kill experiments, our in vitro studies suggest several possible explanations for the observed benefits in patients treated with a combination of ciprofloxacin and rifampin for deep-seated staphylococcal infections. Notably, when growth inhibition rather than killing was used to characterize drug interaction, indifference rather than antagonism was observed. An additive bactericidal effect was observed in nongrowing bacteria suspended in phosphate-buffered saline. While rifampin antagonized the bactericidal effects of ciprofloxacin, ciprofloxacin did not antagonize the bactericidal effects of rifampin. Each antimicrobial prevented the emergence of subpopulations that were resistant to the other. PMID:9174186

Evaluation of the Bactericidal Activity of Plazomicin and Comparators against Multidrug-resistant Enterobacteriaceae.

PubMed

Thwaites, M; Hall, D; Shinabarger, D; Serio, A W; Krause, K M; Marra, A; Pillar, C

2018-06-04

The next-generation aminoglycoside plazomicin, in development for infections due to multi-drug resistant (MDR) Enterobacteriaceae, was evaluated alongside comparators for bactericidal activity in minimum bactericidal concentration (MBC) and time-kill (TK) assays against MDR Enterobacteriaceae isolates with characterized aminoglycoside and β-lactam resistance mechanisms. Overall, plazomicin and colistin were the most potent, with plazomicin demonstrating an MBC 50/90 of 0.5/4 μg/mL and sustained 3-log 10 kill against MDR Escherichia coli , Klebsiella pneumoniae and Enterobacter spp. Copyright © 2018 Thwaites et al.

Naturally occurring anti-Salmonella agents.

PubMed

Kubo, I; Fujita, K

2001-12-01

Polygodial and (2E)-hexenal were found to possess antibacterial activity against Salmonella choleraesuis with the minimum bactericidal concentrations (MBC) of 50 microg/mL (0.17 mM) and 100 microg/mL (0.98 mM), respectively. The time kill curve study showed that these two alpha,beta-unsaturated aldehydes were bactericidal against this food-borne bacterium at any stage of growth. However, they showed different effects on the growth of S. choleraesuis. The combination of polygodial and anethole exhibited strong synergism on their bacteriostatic action but only marginal synergism on their bactericidal action.

Combined roles of human IgG subclass, alternative complement pathway activation, and epitope density in the bactericidal activity of antibodies to meningococcal factor h binding protein.

PubMed

Giuntini, Serena; Reason, Donald C; Granoff, Dan M

2012-01-01

Meningococcal vaccines containing factor H binding protein (fHbp) are in clinical development. fHbp binds human fH, which enables the meningococcus to resist complement-mediated bacteriolysis. Previously, we found that chimeric human IgG1 mouse anti-fHbp monoclonal antibodies (MAbs) had human complement-mediated bactericidal activity only if the MAb inhibited fH binding. Since IgG subclasses differ in their ability to activate complement, we investigated the role of human IgG subclasses on antibody functional activity. We constructed chimeric MAbs in which three different murine fHbp-specific binding domains were each paired with human IgG1, IgG2, or IgG3. Against a wild-type group B isolate, all three IgG3 MAbs, irrespective of their ability to inhibit fH binding, had bactericidal activity that was >5-fold higher than the respective IgG1 MAbs, while the IgG2 MAbs had the least activity. Against a mutant with increased fHbp expression, the anti-fHbp MAbs elicited greater C4b deposition (classical pathway) and greater bactericidal activity than against the wild-type strain, and the IgG1 MAbs had similar or greater activity than the respective IgG3 MAbs. The bactericidal activity against both wild-type and mutant strains also was dependent, in part, on activation of the alternative complement pathway. Thus, at lower epitope density in the wild-type strain, the IgG3 anti-fHbp MAbs had the greatest bactericidal activity. At a higher epitope density in the mutant, the IgG1 MAbs had similar or greater bactericidal activity than the IgG3 MAbs, and the activity was less dependent on the inhibition of fH binding than at a lower epitope density.

Brucella-Salmonella lipopolysaccharide chimeras are less permeable to hydrophobic probes and more sensitive to cationic peptides and EDTA than are their native Brucella sp. counterparts.

PubMed Central

Freer, E; Moreno, E; Moriyón, I; Pizarro-Cerdá, J; Weintraub, A; Gorvel, J P

1996-01-01

A rough (R) Brucella abortus 45/20 mutant was more sensitive to the bactericidal activity of polymyxin B and lactoferricin B than was its smooth (S) counterpart but considerably more resistant than Salmonella montevideo. The outer membrane (OM) and isolated lipopolysaccharide (LPS) of S. montevideo showed a higher affinity for these cationic peptides than did the corresponding B. abortus OM and LPS. We took advantage of the moderate sensitivity of R B. abortus to cationic peptides to construct live R B. abortus-S-LPS chimeras to test the activities of polymyxin B, lactoferricin B, and EDTA. Homogeneous and abundant peripheral distribution of the heterologous S-LPS was observed on the surface of the chimeras, and this coating had no effect on the viability or morphology of the cells. When the heterologous LPS corresponded to the less sensitive bacterium S B. abortus S19, the chimeras were more resistant to cationic peptides; in contrast, when the S-LPS was from the more sensitive bacterium S. montevideo, the chimeras were more susceptible to the action of peptides and EDTA. A direct correlation between the amount of heterologous S-LPS on the surface of chimeric Brucella cells and peptide sensitivity was observed. Whereas the damage produced by polymyxin B in S. montevideo and B. abortus-S. montevideo S-LPS chimeras was manifested mainly as OM blebbing and inner membrane rolling, lactoferricin B caused inner membrane detachment, vacuolization, and the formation of internal electron-dense granules in these cells. Native S and R B. abortus strains were permeable to the hydrophobic probe N-phenyl-1-naphthylamine (NPN). In contrast, only reduced amounts of NPN partitioned into the OMs of the S. montevideo and B. abortus-S. montevideo S-LPS chimeras. Following peptide exposure, accelerated NPN uptake similar to that observed for S. montevideo was detected for the B. abortus-S. montevideo LPS chimeras. The partition of NPN into native or EDTA-, polymyxin B-, or lactoferricin B-treated LPS micelles of S. montevideo or B. abortus mimicked the effects observed with intact cells, and this was confirmed by using micelle hybrids of B. abortus and S. montevideo LPSs. The results showed that LPS is the main cause of B. abortus' resistance to bactericidal cationic peptides, the OM-disturbing action of divalent cationic chelants, and OM permeability to hydrophobic substances. It is proposed that these three features are related to the ability of Brucella bacteria to multiply within phagocytes. PMID:8830680

Brucella-Salmonella lipopolysaccharide chimeras are less permeable to hydrophobic probes and more sensitive to cationic peptides and EDTA than are their native Brucella sp. counterparts.

PubMed

Freer, E; Moreno, E; Moriyón, I; Pizarro-Cerdá, J; Weintraub, A; Gorvel, J P

1996-10-01

A rough (R) Brucella abortus 45/20 mutant was more sensitive to the bactericidal activity of polymyxin B and lactoferricin B than was its smooth (S) counterpart but considerably more resistant than Salmonella montevideo. The outer membrane (OM) and isolated lipopolysaccharide (LPS) of S. montevideo showed a higher affinity for these cationic peptides than did the corresponding B. abortus OM and LPS. We took advantage of the moderate sensitivity of R B. abortus to cationic peptides to construct live R B. abortus-S-LPS chimeras to test the activities of polymyxin B, lactoferricin B, and EDTA. Homogeneous and abundant peripheral distribution of the heterologous S-LPS was observed on the surface of the chimeras, and this coating had no effect on the viability or morphology of the cells. When the heterologous LPS corresponded to the less sensitive bacterium S B. abortus S19, the chimeras were more resistant to cationic peptides; in contrast, when the S-LPS was from the more sensitive bacterium S. montevideo, the chimeras were more susceptible to the action of peptides and EDTA. A direct correlation between the amount of heterologous S-LPS on the surface of chimeric Brucella cells and peptide sensitivity was observed. Whereas the damage produced by polymyxin B in S. montevideo and B. abortus-S. montevideo S-LPS chimeras was manifested mainly as OM blebbing and inner membrane rolling, lactoferricin B caused inner membrane detachment, vacuolization, and the formation of internal electron-dense granules in these cells. Native S and R B. abortus strains were permeable to the hydrophobic probe N-phenyl-1-naphthylamine (NPN). In contrast, only reduced amounts of NPN partitioned into the OMs of the S. montevideo and B. abortus-S. montevideo S-LPS chimeras. Following peptide exposure, accelerated NPN uptake similar to that observed for S. montevideo was detected for the B. abortus-S. montevideo LPS chimeras. The partition of NPN into native or EDTA-, polymyxin B-, or lactoferricin B-treated LPS micelles of S. montevideo or B. abortus mimicked the effects observed with intact cells, and this was confirmed by using micelle hybrids of B. abortus and S. montevideo LPSs. The results showed that LPS is the main cause of B. abortus' resistance to bactericidal cationic peptides, the OM-disturbing action of divalent cationic chelants, and OM permeability to hydrophobic substances. It is proposed that these three features are related to the ability of Brucella bacteria to multiply within phagocytes.

Plasticity of Human THP-1 Cell Phagocytic Activity during Macrophagic Differentiation.

PubMed

Kurynina, A V; Erokhina, M V; Makarevich, O A; Sysoeva, V Yu; Lepekha, L N; Kuznetsov, S A; Onishchenko, G E

2018-03-01

Studies of the role of macrophages in phagocytosis are of great theoretical and practical importance for understanding how these cells are involved in the organism's defense response and in the development of various pathologies. Here we investigated phagocytic plasticity of THP-1 (acute monocytic human leukemia) cells at different stages (days 1, 3, and 7) of phorbol ester (PMA)-induced macrophage differentiation. Analysis of cytokine profiles showed that PMA at a concentration of 100 nM induced development of the proinflammatory macrophage population. The functional activity of macrophages was assessed on days 3 and 7 of differentiation using unlabeled latex beads and latex beads conjugated with ligands (gelatin, mannan, and IgG Fc fragment) that bind to the corresponding specific receptors. The general phagocytic activity increased significantly (1.5-2.0-fold) in the course of differentiation; phagocytosis occurred mostly through the Fc receptors, as shown previously for M1 macrophages. On day 7, the levels of phagocytosis of gelatin- and Fc-covered beads were high; however, the intensity of ingestion of mannan-conjugated beads via mannose receptors increased 2.5-3.0-fold as well, which indicated formation of cells with an alternative phenotype similar to that of M2 macrophages. Thus, the type and the plasticity of phagocytic activity at certain stages of macrophage differentiation can be associated with the formation of functionally mature morphological phenotype. This allows macrophages to exhibit their phagocytic potential in response to specific ligands. These data are of fundamental importance and can be used to develop therapeutic methods for correcting the M1/M2 macrophage ratio in an organism.

Multiple roles of filopodial dynamics in particle capture and phagocytosis and phenotypes of Cdc42 and Myo10 deletion

PubMed Central

Horsthemke, Markus; Bachg, Anne C.; Groll, Katharina; Moyzio, Sven; Müther, Barbara; Hemkemeyer, Sandra A.; Wedlich-Söldner, Roland; Sixt, Michael; Tacke, Sebastian; Bähler, Martin; Hanley, Peter J.

2017-01-01

Macrophage filopodia, finger-like membrane protrusions, were first implicated in phagocytosis more than 100 years ago, but little is still known about the involvement of these actin-dependent structures in particle clearance. Using spinning disk confocal microscopy to image filopodial dynamics in mouse resident Lifeact-EGFP macrophages, we show that filopodia, or filopodia-like structures, support pathogen clearance by multiple means. Filopodia supported the phagocytic uptake of bacterial (Escherichia coli) particles by (i) capturing along the filopodial shaft and surfing toward the cell body, the most common mode of capture; (ii) capturing via the tip followed by retraction; (iii) combinations of surfing and retraction; or (iv) sweeping actions. In addition, filopodia supported the uptake of zymosan (Saccharomyces cerevisiae) particles by (i) providing fixation, (ii) capturing at the tip and filopodia-guided actin anterograde flow with phagocytic cup formation, and (iii) the rapid growth of new protrusions. To explore the role of filopodia-inducing Cdc42, we generated myeloid-restricted Cdc42 knock-out mice. Cdc42-deficient macrophages exhibited rapid phagocytic cup kinetics, but reduced particle clearance, which could be explained by the marked rounded-up morphology of these cells. Macrophages lacking Myo10, thought to act downstream of Cdc42, had normal morphology, motility, and phagocytic cup formation, but displayed markedly reduced filopodia formation. In conclusion, live-cell imaging revealed multiple mechanisms involving macrophage filopodia in particle capture and engulfment. Cdc42 is not critical for filopodia or phagocytic cup formation, but plays a key role in driving macrophage lamellipodial spreading. PMID:28289096

Phagocytic response of astrocytes to damaged neighboring cells

PubMed Central

Cruz, Gladys Mae S.; Ro, Clarissa C.; Moncada, Emmanuel G.; Khatibzadeh, Nima; Flanagan, Lisa A.; Berns, Michael W.

2018-01-01

This study aims to understand the phagocytic response of astrocytes to the injury of neurons or other astrocytes at the single cell level. Laser nanosurgery was used to damage individual cells in both primary mouse cortical astrocytes and an established astrocyte cell line. In both cases, the release of material/substances from laser-irradiated astrocytes or neurons induced a phagocytic response in near-by astrocytes. Propidium iodide stained DNA originating from irradiated cells was visible in vesicles of neighboring cells, confirming phagocytosis of material from damaged cortical cells. In the presence of an intracellular pH indicator dye, newly formed vesicles correspond to acidic pH fluorescence, thus suggesting lysosome bound degradation of cellular debris. Cells with shared membrane connections prior to laser damage had a significantly higher frequency of induced phagocytosis compared to isolated cells with no shared membrane. The increase in phagocytic response of cells with a shared membrane occurred regardless of the extent of shared membrane (a thin filopodial connection vs. a cell cluster with significant shared membrane). In addition to the presence (or lack) of a membrane connection, variation in phagocytic ability was also observed with differences in injury location within the cell and distance separating isolated astrocytes. These results demonstrate the ability of an astrocyte to respond to the damage of a single cell, be it another astrocyte, or a neuron. This single-cell level of analysis results in a better understanding of the role of astrocytes to maintain homeostasis in the CNS, particularly in the sensing and removal of debris in damaged or pathologic nervous tissue. PMID:29708987

Effects of Acer okamotoanum sap on the function of polymorphonuclear neutrophilic leukocytes in vitro and in vivo.

PubMed

An, Beum-Soo; Kang, Ji-Houn; Yang, Hyun; Yang, Mhan-Pyo; Jeung, Eui-Bae

2013-02-01

Sap is a plant fluid that primarily consists of water and small amounts of mineral elements, sugars, hormones and other nutrients. Acer mono (A. mono) is an endemic Korean mono maple which was recently suggested to have health benefits due to its abundant calcium and magnesium ion content. In the present study, we examined the effects of sap from Acer okamotoanum (A. okamotoanum) on the phagocytic response of mouse neutrophils in vivo and rat and canine neutrophils in vitro. We tested the regulation of phagocytic activity, oxidative burst activity (OBA) and the levels of filamentous polymeric actin (F-actin) in the absence and presence of dexamethasone (DEX) in vitro and in vivo. Our results showed that DEX primarily reduced OBA in the mouse neutrophils, and that this was reversed in the presence of the sap. By contrast, the phagocytic activity of the mouse cells was not regulated by either DEX or the sap. Rat and canine polymorphonuclear neutrophilic leukocytes (PMNs) responded in vitro to the sap in a similar manner by increasing OBA. However, regulation of phagocytic activity by the sap was different between the species. In canine PMNs, phagocytic activity was enhanced by the sap at a high dose, while it did not significantly modulate this activity in rat PMNs. These findings suggest that the sap of A. okamotoanum stimulates neutrophil activity in the mouse, rat and canine by increasing OBA in vivo and in vitro, and thus may have a potential antimicrobial effect in the PMNs of patients with infections.

Robust Phagocyte Recruitment Controls the Opportunistic Fungal Pathogen Mucor circinelloides in Innate Granulomas In Vivo

PubMed Central

2018-01-01

ABSTRACT Mucormycosis is an emerging fungal infection with extremely high mortality rates in patients with defects in their innate immune response, specifically in functions mediated through phagocytes. However, we currently have a limited understanding of the molecular and cellular interactions between these innate immune effectors and mucormycete spores during the early immune response. Here, the early events of innate immune recruitment in response to infection by Mucor circinelloides spores are modeled by a combined in silico modeling approach and real-time in vivo microscopy. Phagocytes are rapidly recruited to the site of infection in a zebrafish larval model of mucormycosis. This robust early recruitment protects from disease onset in vivo. In silico analysis identified that protection is dependent on the number of phagocytes at the infection site, but not the speed of recruitment. The mathematical model highlights the role of proinflammatory signals for phagocyte recruitment and the importance of inhibition of spore germination for protection from active fungal disease. These in silico data are supported by an in vivo lack of fungal spore killing and lack of reactive oxygen burst, which together result in latent fungal infection. During this latent stage of infection, spores are controlled in innate granulomas in vivo. Disease can be reactivated by immunosuppression. Together, these data represent the first in vivo real-time analysis of innate granuloma formation during the early stages of a fungal infection. The results highlight a potential latent stage during mucormycosis that should urgently be considered for clinical management of patients. PMID:29588406

Bactericidal activity of tracheal antimicrobial peptide against respiratory pathogens of cattle.

PubMed

Taha-Abdelaziz, Khaled; Perez-Casal, José; Schott, Courtney; Hsiao, Jason; Attah-Poku, Samuel; Slavić, Durđa; Caswell, Jeff L

2013-04-15

Tracheal antimicrobial peptide (TAP) is a β-defensin produced by mucosal epithelial cells of cattle. Although effective against several human pathogens, the activity of this bovine peptide against the bacterial pathogens that cause bovine respiratory disease have not been reported. This study compared the antibacterial effects of synthetic TAP against Mannheimia haemolytica, Histophilus somni, Pasteurella multocida, and Mycoplasma bovis. Bactericidal activity against M. bovis was not detected. In contrast, the Pasteurellaceae bacteria showed similar levels of susceptibility to that of Escherichia coli, with 0.125μg TAP inhibiting growth in a radial diffusion assay and minimum inhibitory concentrations of 1.56-6.25μg/ml in a bactericidal assay. Significant differences among isolates were not observed. Sequencing of exon 2 of the TAP gene from 23 cattle revealed a prevalent non-synonymous single nucleotide polymorphism (SNP) A137G, encoding either serine or asparagine at residue 20 of the mature peptide. The functional effect of this SNP was tested against M. haemolytica using synthetic peptides. The bactericidal effect of the asparagine-containing peptide was consistently higher than the serine-containing peptide. Bactericidal activities were similar for an acapsular mutant of M. haemolytica compared to the wild type. These findings indicate that the Pasteurellaceae bacteria that cause bovine respiratory disease are susceptible to killing by bovine TAP and appear not to have evolved resistance, whereas M. bovis appears to be resistant. A non-synonymous SNP was identified in the coding region of the TAP gene, and the corresponding peptides vary in their bactericidal activity against M. haemolytica. Copyright © 2013 Elsevier B.V. All rights reserved.

Comparative study of the bactericidal effects of indocyanine green- and methyl aminolevulinate-based photodynamic therapy on Propionibacterium acnes as a new treatment for acne.

PubMed

Choi, Seung-Hwan; Seo, Jeong-Wan; Kim, Ki-Ho

2018-05-03

Acne vulgaris is one of the most common dermatological problems, and its therapeutic options include topical and systemic retinoids and antibiotics. However, increase in problems associated with acne treatment, such as side-effects from conventional agents and bacterial resistance to antibiotics, has led to greater use of photodynamic therapy. The purpose of this study was to compare the bactericidal effects of indocyanine green- and methyl aminolevulinate-based photodynamic therapy on Propionibacterium acnes. P. acnes were cultured under anaerobic conditions; then they were divided into three groups (control, treated with indocyanine green and treated with methyl aminolevulinate) and illuminated with different lights (630-nm light-emitting diode, 805-nm diode laser and 830-nm light-emitting diode). The bactericidal effects were evaluated by comparing each group's colony-forming units. The cultured P. acnes were killed with an 805-nm diode laser and 830-nm light-emitting diode in the indocyanine green group. No bactericidal effects of methyl aminolevulinate-based photodynamic therapy were identified. The clinical efficacy of indocyanine green-based photodynamic therapy in 21 patients was retrospectively analyzed. The Korean Acne Grading System was used to evaluate treatment efficacy, which was significantly decreased after treatment. The difference in the efficacy of the 805-nm diode laser and 830-nm light-emitting diode was not statistically significant. Although the methyl aminolevulinate-based photodynamic therapy showed no bactericidal effect, the indocyanine green-based photodynamic therapy has bactericidal effect and clinical efficacy. © 2018 Japanese Dermatological Association.

Evaluation of antimicrobial peptides as novel bactericidal agents for room temperature-stored platelets.

PubMed

Mohan, Ketha V K; Rao, Shilpakala Sainath; Atreya, Chintamani D

2010-01-01

A single cost-effective pathogen inactivation approach would help to improve the safety of our nation's blood supply. Several methods and technologies are currently being studied to help reduce bacterial contamination of blood components. There is clearly need for simple and easy-to-use pathogen inactivation techniques specific to plasma, platelets (PLTs), and red blood cells. In this report, we introduce a novel proof of concept: using known therapeutic antimicrobial peptides (AMPs) as bactericidal agents for room temperature-stored PLT concentrates (PCs). Nine synthetic AMPs, four from PLT microbicidal protein-derived peptides (PD1-4) and five Arg-Trp (RW) repeat peptides containing one to five repeats, were tested for bactericidal activity in plasma and PC samples spiked with Staphylococcus aureus, S. epidermidis, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Bacillus cereus. A 3-log reduction of viable bacteria was considered as the bactericidal activity of a given peptide. In both plasma alone and PCs, RW3 peptide demonstrated bactericidal activity against S. aureus, S. epidermidis, E. coli, P. aeruginosa, and K. pneumoniae; PD4 and RW2 against P. aeruginosa; and RW4 against K. pneumoniae. The activity of each of these four peptides against the remaining bacterial species in the test panel resulted in less than a 3-log reduction in the number of viable bacteria and hence considered ineffective. These findings suggest a new approach to improving the safety of blood components, demonstrating the potential usefulness of screening therapeutic AMPs against selected bacteria to identify suitable bactericidal agents for stored plasma, PCs, and other blood products.

Effect of the Gc-derived macrophage-activating factor precursor (preGcMAF) on phagocytic activation of mouse peritoneal macrophages.

PubMed

Uto, Yoshihiro; Yamamoto, Syota; Takeuchi, Ryota; Nakagawa, Yoshinori; Hirota, Keiji; Terada, Hiroshi; Onizuka, Shinya; Nakata, Eiji; Hori, Hitoshi

2011-07-01

The 1f1f subtype of the Gc protein (Gc(1f1f) protein) was converted into Gc-derived macrophage-activating factor (GcMAF) by enzymatic processing in the presence of β-galactosidase of an activated B-cell and sialidase of a T-cell. We hypothesized that preGc(1f1f)MAF, the only Gc(1f1f) protein lacking galactose, can be converted to GcMAF in vivo because sialic acid is cleaved by residual sialidase. Hence, we investigated the effect of preGc(1f1f)MAF on the phagocytic activation of mouse peritoneal macrophages. We examined the sugar moiety of preGc(1f1f)MAF with a Western blot using peanut agglutinin (PNA) and Helix pomatia agglutinin (HPA) lectin. We also found that preGc(1f1f)MAF significantly enhanced phagocytic activity in mouse peritoneal macrophages but only in the presence of the mouse peritoneal fluid; the level of phagocytic activity was the same as that observed for GcMAF. PreGc(1f1f)MAF can be used as an effective macrophage activator in vivo.

Cell mediated immune response of the Mediterranean sea urchin Paracentrotus lividus after PAMPs stimulation.

PubMed

Romero, A; Novoa, B; Figueras, A

2016-09-01

The Mediterranean sea urchin (Paracentrotus lividus) is of great ecological and economic importance for the European aquaculture. Yet, most of the studies regarding echinoderm's immunological defense mechanisms reported so far have used the sea urchin Strongylocentrotus purpuratus as a model, and information on the immunological defense mechanisms of Paracentrotus lividus and other sea urchins, is scarce. To remedy this gap in information, in this study, flow cytometry was used to evaluate several cellular immune mechanisms, such as phagocytosis, cell cooperation, and ROS production in P. lividus coelomocytes after PAMP stimulation. Two cell populations were described. Of the two, the amoeboid-phagocytes were responsible for the phagocytosis and ROS production. Cooperation between amoeboid-phagocytes and non-adherent cells resulted in an increased phagocytic response. Stimulation with several PAMPs modified the phagocytic activity and the production of ROS. The premise that the coelomocytes were activated by the bacterial components was confirmed by the expression levels of two cell mediated immune genes: LPS-Induced TNF-alpha Factor (LITAF) and macrophage migration inhibitory factor (MIF). These results have helped us understand the cellular immune mechanisms in P. lividus and their modulation after PAMP stimulation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Defining Mononuclear Phagocyte Subset Homology Across Several Distant Warm-Blooded Vertebrates Through Comparative Transcriptomics

PubMed Central

Vu Manh, Thien-Phong; Elhmouzi-Younes, Jamila; Urien, Céline; Ruscanu, Suzana; Jouneau, Luc; Bourge, Mickaël; Moroldo, Marco; Foucras, Gilles; Salmon, Henri; Marty, Hélène; Quéré, Pascale; Bertho, Nicolas; Boudinot, Pierre; Dalod, Marc; Schwartz-Cornil, Isabelle

2015-01-01

Mononuclear phagocytes are organized in a complex system of ontogenetically and functionally distinct subsets, that has been best described in mouse and to some extent in human. Identification of homologous mononuclear phagocyte subsets in other vertebrate species of biomedical, economic, and environmental interest is needed to improve our knowledge in physiologic and physio-pathologic processes, and to design intervention strategies against a variety of diseases, including zoonotic infections. We developed a streamlined approach combining refined cell sorting and integrated comparative transcriptomics analyses which revealed conservation of the mononuclear phagocyte organization across human, mouse, sheep, pigs and, in some respect, chicken. This strategy should help democratizing the use of omics analyses for the identification and study of cell types across tissues and species. Moreover, we identified conserved gene signatures that enable robust identification and universal definition of these cell types. We identified new evolutionarily conserved gene candidates and gene interaction networks for the molecular regulation of the development or functions of these cell types, as well as conserved surface candidates for refined subset phenotyping throughout species. A phylogenetic analysis revealed that orthologous genes of the conserved signatures exist in teleost fishes and apparently not in Lamprey. PMID:26150816

[EFFECT OF LACTOBACILLI EXOPOLYSACCHARIDES ON PHAGOCYTE AND CYTOKINE ACTIVITY IN VITRO AND IN ANIMAL ORGANISM DURING INFECTIOUS PROCESS MODELING].

PubMed

Gorelnikova, E A; Karpunina, L V

2015-01-01

Study the effect of lactobacilli exopolysaccharides (EPS)on cytokine and phagocyte activity in vitro and in mice organism during modelling of an infectious process. Lactobacillus delbrueckii subsp. delbrueckii B-1596 (laksaran 1596), L. delbrueckii B-1936 (laksaran 1936) and L. delbrueckii ssp. bulgaricus (laksaran Z) were used in the study. EPS were administered into white mice 1 hour after the Staphylococcus aureus 209-P infection. Index of phagocyte completion and index of killing activation (IKA) were calculated during phagocyte activity study. IL-1α, TNF-α, IFN-γ and IL-4 cytokine content was determined in blood sera and macrophage supernatants. Laksaran 1596, 1936 and Z had ambiguous effect on cytokine production. Laksaran: Z and 1936, 6 hours after mice infection increased IL-1 content in blood sera. Laksaran Z had the most pronounced effect on macrophages, resulting in an increase of active macrophages, facilitating increased digestion of S. aureus 209-P and IKA increase, stimulated cytokine production. The results obtained allow to speak about a possibility of using laksaran Z as a prophylaxis immune modulating preparation for correction of animal cytokine status.

Beginnings of a good apoptotic meal: the find-me and eat-me signaling pathways

PubMed Central

Ravichandran, Kodi S.

2011-01-01

Prompt and efficient clearance of apoptotic cells is necessary to prevent secondary necrosis of dying cells, and to avoid immune responses to autoantigens. Recent studies have shed light on how apoptotic cells through soluble ‘find-me signals’ advertise their presence to phagocytes at the earliest stages of cell death. Phagocytes sense the find-me signal gradient, and in turn the presence of dying cells, and migrate to their vicinity. The apoptotic cells also expose specific eat-me signals on their surface that are recognized by phagocytes through specific engulfment receptors. This review covers the recent progress in the areas of find-me and eat-me signals, and how these relate to prompt and immunologically silent clearance of apoptotic cells. PMID:22035837

Comparison of bactericidal efficiency of 7.5 MeV X-rays, gamma-rays, and 10 MeV e-beams

NASA Astrophysics Data System (ADS)

Song, Beom-Seok; Lee, Yunjong; Moon, Byeong-Geum; Go, Seon-Min; Park, Jong-Heum; Kim, Jae-Kyung; Jung, Koo; Kim, Dong-Ho; Ryu, Sang-Ryeol

2016-08-01

This study was performed to verify the feasibility of 7.5 MeV X-rays for food pasteurization through a comparison of the bactericidal efficiency with those of other sources for selected bacterial pathogens. No significant differences were observed between the overall bactericidal efficiency for beef-inoculated pathogens based on the uncertainty of the absorbed dose and variations in bacterial counts. This result supported that all three irradiation sources were effective for inactivation of food-borne bacteria and that 7.5 MeV X-rays may be used for food pasteurization.

In vitro bactericidal activity of enrofloxacin against gyrA mutant and qnr-containing Escherichia coli isolates from animals.

PubMed

Cengiz, M; Sahinturk, P; Sonal, S; Buyukcangaz, E; Sen, A; Arslan, E

2013-05-04

The objective of this work was to investigate the bactericidal activity of enrofloxacin against gyrA mutant and qnr-containing Escherichia coli isolates from animals. The minimum inhibitory concentrations (MICs) of gyrA mutant and qnr-containing E coli isolates ranged from 1 µg/ml to 32 µg/ml for enrofloxacin. Time-kill experiments were performed using selected E coli isolates. For the time-kill experiments, the colony counts were determined by plating each diluted sample onto plate count agar and an integrated pharmacokinetic/pharmacodynamics area measure (log ratio area) was applied to the colony-forming units (cfu) data. In general, enrofloxacin exhibited bactericidal activity against all the gyrA mutant E coli isolates at all concentrations greater than four times the MIC. However, the bactericidal activity of enrofloxacin for all the qnr-containing E coli isolates was less dependent on concentration. The results of the present study indicated that the genetic mechanism of resistance might account for the different bactericidal activities of enrofloxacin observed for the gyrA mutant and the qnr-containing E coli isolates. Therefore, in addition to MIC assays, genetic mechanism-based pharmacodynamic models should be used to provide accurate predictions of the effects of drugs on resistant bacteria.

Effects of bacteriocins on methicillin-resistant Staphylococcus aureus biofilm.

PubMed

Okuda, Ken-ichi; Zendo, Takeshi; Sugimoto, Shinya; Iwase, Tadayuki; Tajima, Akiko; Yamada, Satomi; Sonomoto, Kenji; Mizunoe, Yoshimitsu

2013-11-01

Control of biofilms formed by microbial pathogens is an important subject for medical researchers, since the development of biofilms on foreign-body surfaces often causes biofilm-associated infections in patients with indwelling medical devices. The present study examined the effects of different kinds of bacteriocins, which are ribosomally synthesized antimicrobial peptides produced by certain bacteria, on biofilms formed by a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA). The activities and modes of action of three bacteriocins with different structures (nisin A, lacticin Q, and nukacin ISK-1) were evaluated. Vancomycin, a glycopeptide antibiotic used in the treatment of MRSA infections, showed bactericidal activity against planktonic cells but not against biofilm cells. Among the tested bacteriocins, nisin A showed the highest bactericidal activity against both planktonic cells and biofilm cells. Lacticin Q also showed bactericidal activity against both planktonic cells and biofilm cells, but its activity against biofilm cells was significantly lower than that of nisin A. Nukacin ISK-1 showed bacteriostatic activity against planktonic cells and did not show bactericidal activity against biofilm cells. Mode-of-action studies indicated that pore formation leading to ATP efflux is important for the bactericidal activity against biofilm cells. Our results suggest that bacteriocins that form stable pores on biofilm cells are highly potent for the treatment of MRSA biofilm infections.

Effects of Bacteriocins on Methicillin-Resistant Staphylococcus aureus Biofilm

PubMed Central

Zendo, Takeshi; Sugimoto, Shinya; Iwase, Tadayuki; Tajima, Akiko; Yamada, Satomi; Sonomoto, Kenji

2013-01-01

Control of biofilms formed by microbial pathogens is an important subject for medical researchers, since the development of biofilms on foreign-body surfaces often causes biofilm-associated infections in patients with indwelling medical devices. The present study examined the effects of different kinds of bacteriocins, which are ribosomally synthesized antimicrobial peptides produced by certain bacteria, on biofilms formed by a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA). The activities and modes of action of three bacteriocins with different structures (nisin A, lacticin Q, and nukacin ISK-1) were evaluated. Vancomycin, a glycopeptide antibiotic used in the treatment of MRSA infections, showed bactericidal activity against planktonic cells but not against biofilm cells. Among the tested bacteriocins, nisin A showed the highest bactericidal activity against both planktonic cells and biofilm cells. Lacticin Q also showed bactericidal activity against both planktonic cells and biofilm cells, but its activity against biofilm cells was significantly lower than that of nisin A. Nukacin ISK-1 showed bacteriostatic activity against planktonic cells and did not show bactericidal activity against biofilm cells. Mode-of-action studies indicated that pore formation leading to ATP efflux is important for the bactericidal activity against biofilm cells. Our results suggest that bacteriocins that form stable pores on biofilm cells are highly potent for the treatment of MRSA biofilm infections. PMID:23979748

Effects of oakmoss and its components on biofilm formation of Legionella pneumophila.

PubMed

Nomura, Harue; Isshiki, Yasunori; Sakuda, Keisuke; Sakuma, Katsuya; Kondo, Seiichi

2013-01-01

Oakmoss and its components are known as antibacterial agents, specifically against Legionella pneumophila. In the present study, we investigated the effects of oakmoss and its components (phenol, didepside and isochromen derivatives) on L. pneumophila biofilm formation, with particular reference to the bactericidal activity (minimum bactericidal concentration; MBC) of these components against the bacterial cells in the biofilm. Of the 20 compounds tested, two didepside derivatives and four phenol derivatives reduced biofilm formation by more than 50% of that observed for the control at their respective minimum inhibitory concentrations (1/2×MIC). The inhibitory activities of these compounds were either equivalent to or greater than that of the clarithromycin reference. Isochromen derivatives had no effect on biofilm formation. Analysis of bactericidal activity of didepside and isochromen derivatives revealed that three of four didepside derivatives and one of four isochromen derivatives exhibited high bactericidal activity (MBC: 32.0-74.7 µg/mL) against the L. pneumophila in the biofilm after 24 h or 48 h of co-incubation; the antibacterial activities of these compounds were almost equivalent to clarithromycin and chlorhexidine gluconate (MBC: 42.7-64.0 µg/mL) that were used as references. Thus, based on their anti-biofilm forming and bactericidal activities, didepside derivatives are considered to be good candidates for disinfectants against L. pneumophila.

Superhydrophilic nanopillar-structured quartz surfaces for the prevention of biofilm formation in optical devices

NASA Astrophysics Data System (ADS)

Han, Soo; Ji, Seungmuk; Abdullah, Abdullah; Kim, Duckil; Lim, Hyuneui; Lee, Donghyun

2018-01-01

Bacterial biofilm formation on optical devices such as contact lenses, optical glasses, endoscopic devices, and microscopic slides and lenses are major concerns in the field of medicine and biomedical engineering. To solve these problems, here we present the first report of superhydrophilic transparent nanopillar-structured surfaces with bactericidal properties. To construct bactericidal surfaces, we imitated a topological mechanism found in nature in which nanopillar-structured surfaces cause a mechanical disruption of the outer cell membranes of bacteria, resulting in bacterial cell death. We used nanosphere lithography to fabricate nanopillars with various sharpnesses and heights on a quartz substrate. Water contact angle and light reflectance measurements revealed superhydrophilic, antifogging and antireflective properties, which are important for use in optical devices. To determine bactericidal efficiency, the fabricated surfaces were incubated and tested against two Gram-negative bacteria associated with biofilm formation and various diseases in humans, Pseudomonas aeruginosa and Escherichia coli. The highest bactericidal activity was achieved with nanopillars that measured 300 nm in height and 10 nm in apex diameter. Quartz substrates patterned with such nanopillars killed ∼38,000 P. aeruginosa and ∼27,000 E. coli cells cm-2 min-1, respectively. Thus, the newly designed nanopillar-structured bactericidal surfaces are suitable for use in the development of superhydrophilic and transparent optical devices.

The Effect of Long-Term Storage on the Physiochemical and Bactericidal Properties of Electrochemically Activated Solutions

PubMed Central

Robinson, Gareth; Thorn, Robin; Reynolds, Darren

2013-01-01

Electrochemically activated solutions (ECAS) are generated by electrolysis of NaCl solutions, and demonstrate broad spectrum antimicrobial activity and high environmental compatibility. The biocidal efficacy of ECAS at the point of production is widely reported in the literature, as are its credentials as a “green biocide.” Acidic ECAS are considered most effective as biocides at the point of production and ill suited for extended storage. Acidic ECAS samples were stored at 4 °C and 20 °C in glass and polystyrene containers for 398 days, and tested for free chlorine, pH, ORP and bactericidal activity throughout. ORP and free chlorine (mg/L) in stored ECAS declined over time, declining at the fastest rate when stored at 20 °C in polystyrene and at the slowest rate when stored at 4 °C in glass. Bactericidal efficacy was also affected by storage and ECAS failed to produce a 5 log10 reduction on five occasions when stored at 20 °C. pH remained stable throughout the storage period. This study represents the longest storage evaluation of the physiochemical parameters and bactericidal efficacy of acidic ECAS within the published literature and reveals that acidic ECAS retain useful bactericidal activity for in excess of 12 months, widening potential applications. PMID:23263673

The effect of long-term storage on the physiochemical and bactericidal properties of electrochemically activated solutions.

PubMed

Robinson, Gareth; Thorn, Robin; Reynolds, Darren

2012-12-24

Electrochemically activated solutions (ECAS) are generated by electrolysis of NaCl solutions, and demonstrate broad spectrum antimicrobial activity and high environmental compatibility. The biocidal efficacy of ECAS at the point of production is widely reported in the literature, as are its credentials as a "green biocide." Acidic ECAS are considered most effective as biocides at the point of production and ill suited for extended storage. Acidic ECAS samples were stored at 4 °C and 20 °C in glass and polystyrene containers for 398 days, and tested for free chlorine, pH, ORP and bactericidal activity throughout. ORP and free chlorine (mg/L) in stored ECAS declined over time, declining at the fastest rate when stored at 20 °C in polystyrene and at the slowest rate when stored at 4 °C in glass. Bactericidal efficacy was also affected by storage and ECAS failed to produce a 5 log(10) reduction on five occasions when stored at 20 °C. pH remained stable throughout the storage period. This study represents the longest storage evaluation of the physiochemical parameters and bactericidal efficacy of acidic ECAS within the published literature and reveals that acidic ECAS retain useful bactericidal activity for in excess of 12 months, widening potential applications.

Suppression of bactericidal activity of human polymorphonuclear leukocytes by Bacteroides gingivalis.

PubMed Central

Yoneda, M; Maeda, K; Aono, M

1990-01-01

The direct effects of the culture supernatant of oral microorganisms on the bactericidal activity of human polymorphonuclear leukocytes (PMNs) were investigated. The bactericidal activity of PMNs, which were preincubated with the supernatant of Bacteroides gingivalis, Bacteroides intermedius, Bacteroides melaninogenicus or phosphate-buffered saline, was examined by counting the surviving bacteria. B. gingivalis-treated PMNs were found to have a diminished ability for killing bacteria in the presence or absence of serum. The chemiluminescence response of PMNs, which were preincubated with the culture supernatant of B. gingivalis, was strikingly reduced compared with that of PMNs preincubated with phosphate-buffered saline or other bacterial culture supernatants. The production of superoxide anion (O2-) by PMNs stimulated with either formyl-methionyl-leucyl-phenylalanine or phorbol myristate acetate was reduced in both cases after the PMNs were preincubated with the culture supernatant of B. gingivalis. However, it was observed that there was more reduction in superoxide anion (O2-) production stimulated with formyl-methionyl-leucyl-phenylalanine compared with that stimulated with phorbol myristate acetate. These results suggest that B. gingivalis releases a factor which interferes with the bactericidal activity of PMNs by modulating the generation of reactive oxygen species. These suppressive effects on bactericidal activity may be important in the pathogenesis of this microorganism. PMID:2153632

The nature of inherent bactericidal activity: insights from the nanotopology of three species of dragonfly

NASA Astrophysics Data System (ADS)

Mainwaring, David E.; Nguyen, Song Ha; Webb, Hayden; Jakubov, Timur; Tobin, Mark; Lamb, Robert N.; Wu, Alex H.-F.; Marchant, Richard; Crawford, Russell J.; Ivanova, Elena P.

2016-03-01

While insect wings are widely recognised as multi-functional, recent work showed that this extends to extensive bactericidal activity brought about by cell deformation and lysis on the wing nanotopology. We now quantitatively show that subtle changes to this topography result in substantial changes in bactericidal activity that are able to span an order of magnitude. Notably, the chemical composition of the lipid nanopillars was seen by XPS and synchrotron FTIR microspectroscopy to be similar across these activity differences. Modelling the interaction between bacterial cells and the wing surface lipids of 3 species of dragonflies, that inhabit similar environments, but with distinctly different behavioural repertoires, provided the relationship between surface structure and antibacterial functionality. In doing so, these principal behavioural patterns correlated with the demands for antimicrobial efficiency dictated by differences in their foraging strategies. This work now reveals a new feature in the design elegance of natural multi-functional surfaces as well providing insights into the bactericidal mechanism underlying inherently antimicrobial materials, while suggesting that nanotopology is related to the evolutionary development of a species through the demands of its behavioural repertoire. The underlying relationship between the processes of wetting, adhesion and capillarity of the lipid nanopillars and bactericidal efficiency suggests new prospects for purely mechano-responsive antibacterial surfaces.While insect wings are widely recognised as multi-functional, recent work showed that this extends to extensive bactericidal activity brought about by cell deformation and lysis on the wing nanotopology. We now quantitatively show that subtle changes to this topography result in substantial changes in bactericidal activity that are able to span an order of magnitude. Notably, the chemical composition of the lipid nanopillars was seen by XPS and synchrotron FTIR microspectroscopy to be similar across these activity differences. Modelling the interaction between bacterial cells and the wing surface lipids of 3 species of dragonflies, that inhabit similar environments, but with distinctly different behavioural repertoires, provided the relationship between surface structure and antibacterial functionality. In doing so, these principal behavioural patterns correlated with the demands for antimicrobial efficiency dictated by differences in their foraging strategies. This work now reveals a new feature in the design elegance of natural multi-functional surfaces as well providing insights into the bactericidal mechanism underlying inherently antimicrobial materials, while suggesting that nanotopology is related to the evolutionary development of a species through the demands of its behavioural repertoire. The underlying relationship between the processes of wetting, adhesion and capillarity of the lipid nanopillars and bactericidal efficiency suggests new prospects for purely mechano-responsive antibacterial surfaces. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08542j

Early decreased TLR2 expression on monocytes is associated with their reduced phagocytic activity and impaired maturation in a porcine polytrauma model

PubMed Central

Schimunek, Lukas; Serve, Rafael; Teuben, Michel P. J.; Störmann, Philipp; Auner, Birgit; Woschek, Mathias; Pfeifer, Roman; Horst, Klemens; Simon, Tim-P.; Kalbitz, Miriam; Sturm, Ramona; Pape, Hans-C.; Hildebrand, Frank; Marzi, Ingo

2017-01-01

In their post-traumatic course, trauma patients suffering from multiple injuries have a high risk for immune dysregulation, which may contribute to post-injury complications and late mortality. Monocytes as specific effector cells of the innate immunity play a crucial role in inflammation. Using their Pattern Recognition Receptors (PRRs), notably Toll-Like Receptors (TLR), the monocytes recognize pathogens and/or pathogen-associated molecular patterns (PAMPs) and organize their clearance. TLR2 is the major receptor for particles of gram-positive bacteria, and initiates their phagocytosis. Here, we investigated the phagocytizing capability of monocytes in a long-term porcine severe trauma model (polytrauma, PT) with regard to their TLR2 expression. Polytrauma consisted of femur fracture, unilateral lung contusion, liver laceration, hemorrhagic shock with subsequent resuscitation and surgical fracture fixation. After induction of PT, peripheral blood was withdrawn before (-1 h) and directly after trauma (0 h), as well as 3.5 h, 5.5 h, 24 h and 72 h later. CD14+ monocytes were identified and the expression levels of H(S)LA-DR and TLR2 were investigated by flow cytometry. Additionally, the phagocytizing activity of monocytes by applying S. aureus particles labelled with pHrodo fluorescent reagent was also assessed by flow cytometry. Furthermore, blood samples from 10 healthy pigs were exposed to a TLR2-neutralizing antibody and subsequently to S. aureus particles. Using flow cytometry, phagocytizing activity was determined. P below 0.05 was considered significant. The number of CD14+ monocytes of all circulating leukocytes remained constant during the observational time period, while the percentage of CD14+H(S)LA-DR+ monocytes significantly decreased directly, 3.5 h and 5.5 h after trauma. The percentage of TLR2+ expressing cells out of all monocytes significantly decreased directly, 3.5 h and 5.5 h after trauma. The percentage of phagocytizing monocytes decreased immediately and remained lower during the first 3.5 h after trauma, but increased after 24 h. Antagonizing TLR2 significantly decreased the phagocytizing activity of monocytes. Both, decreased percentage of activated as well as TLR2 expressing monocytes persisted as long as the reduced phagocytosis was observed. Moreover, neutralizing TLR2 led to a reduced capability of phagocytosis as well. Therefore, we assume that reduced TLR2 expression may be responsible for the decreased phagocytizing capacity of circulating monocytes in the early post-traumatic phase. PMID:29125848

A novel phagocytic receptor (CgNimC) from Pacific oyster Crassostrea gigas with lipopolysaccharide and gram-negative bacteria binding activity.

PubMed

Wang, Weilin; Liu, Rui; Zhang, Tao; Zhang, Ran; Song, Xuan; Wang, Lingling; Song, Linsheng

2015-03-01

Phagocytosis is an evolutionarily conserved process to ingest the invading microbes and apoptotic or necrotic corpses, playing vital roles in defensing invaders and maintenance of normal physiological conditions. In the present study, a new Nimrod family phagocytic receptor with three EGF-like domains was identified in Pacific oyster Crassostrea gigas (designated CgNimC). CgNimC shared homology with other identified multiple EGF-like domain containing proteins. The mRNA transcripts of CgNimC were mainly distributed in mantle and hemocytes. Its relative expression level in hemocytes was significantly (P < 0.01) up-regulated after the injection of bacteria Vibrio anguillarum. Different to the NimC in Drosophila and Anopheles gambiae, the recombinant protein of CgNimC (rCgNimC) could bind directly to two gram-negative bacteria V. anguillarum and Vibrio splendidus, but not to gram-positive bacteria Staphylococci aureus, Micrococcus luteus or fungi Yarrowia lipolytica and Pichia pastoris. The affinity of rCgNimC toward M. luteus and Y. lipolytica was enhanced when the microorganisms were pre-incubated with the cell free hemolymph. rCgNimC exhibited higher affinity to lipopolysaccharide (LPS) and relatively lower affinity to peptidoglycan (PGN), while no affinity to glucan (GLU). After the CgNimC receptor was blocked by anti-rCgNimC antibody in vitro, the phagocytic rate of hemocytes toward two gram-negative bacteria V. anguillarum and V. splendidus was reduced significantly (P < 0.05), but no significant change of phagocytic rate was observed toward M. luteus and Y. lipolytica. All these results implied that CgNimC, with significant binding capability to LPS and gram-negative bacteria, was a novel phagocytic receptor involved in immune response of Pacific oyster. Further, it was speculated that receptors of Nimrod family might function as a phagocytic receptor to recognize PAMPs on the invaders and its recognition could be promoted by opsonization of molecules in hemolymph. Copyright © 2014 Elsevier Ltd. All rights reserved.

Adjuvant Effect of Killed Propionibacterium acnes on Mouse Peritoneal B-1 Lymphocytes and Their Early Phagocyte Differentiation

PubMed Central

Mussalem, Juliana Sekeres; Squaiella-Baptistão, Carla Cristina; Teixeira, Daniela; Yendo, Tatiana Mina; Thies, Felipe Garutti; Popi, Ana Flavia; Mariano, Mario; Longo-Maugéri, Ieda

2012-01-01

B-1 lymphocytes are the predominant cells in mouse peritoneal cavity. They express macrophage and lymphocyte markers and are divided into B-1a, B-1b and B-1c subtypes. The role of B-1 cells is not completely clear, but they are responsible for natural IgM production and seem to play a regulatory role. An enriched B-1b cell population can be obtained from non-adherent peritoneal cell cultures, and we have previously demonstrated that these cells undergo differentiation to acquire a mononuclear phagocyte phenotype upon attachment to the substrate in vitro. Nevertheless, the B-1 cell response to antigens or adjuvants has been poorly investigated. Because killed Propionibacterium acnes exhibits immunomodulatory effects on both macrophages and B-2 lymphocytes, we analyzed whether a killed bacterial suspension or its soluble polysaccharide (PS) could modulate the absolute number of peritoneal B-1 cells in BALB/c mice, the activation status of these cells and their ability to differentiate into phagocytes in vitro. In vivo, P. acnes treatment elevated the absolute number of all B-1 subsets, whereas PS only increased B-1c. Moreover, the bacterium increased the number of B-1b cells that were positive for MHC II, TLR2, TLR4, TLR9, IL-4, IL-5 and IL-12, in addition to up-regulating TLR9, CD80 and CD86 expression. PS increased B-1b cell expression of TLR4, TLR9, CD40 and CD86, as well as IL-10 and IL-12 synthesis. Both of the treatments decreased the absolute number of B-1b cells in vitro, suggesting their early differentiation into B-1 cell-derived phagocytes (B-1CDP). We also observed a higher phagocytic activity from the phagocytes that were derived from B-1b cells after P. acnes and PS treatment. The adjuvant effect that P. acnes has on B-1 cells, mainly the B-1b subtype, reinforces the importance of B-1 cells in the innate and adaptive immune responses. PMID:22448280

Adjuvant effect of killed Propionibacterium acnes on mouse peritoneal B-1 lymphocytes and their early phagocyte differentiation.

PubMed

Mussalem, Juliana Sekeres; Squaiella-Baptistão, Carla Cristina; Teixeira, Daniela; Yendo, Tatiana Mina; Thies, Felipe Garutti; Popi, Ana Flavia; Mariano, Mario; Longo-Maugéri, Ieda

2012-01-01

B-1 lymphocytes are the predominant cells in mouse peritoneal cavity. They express macrophage and lymphocyte markers and are divided into B-1a, B-1b and B-1c subtypes. The role of B-1 cells is not completely clear, but they are responsible for natural IgM production and seem to play a regulatory role. An enriched B-1b cell population can be obtained from non-adherent peritoneal cell cultures, and we have previously demonstrated that these cells undergo differentiation to acquire a mononuclear phagocyte phenotype upon attachment to the substrate in vitro. Nevertheless, the B-1 cell response to antigens or adjuvants has been poorly investigated. Because killed Propionibacterium acnes exhibits immunomodulatory effects on both macrophages and B-2 lymphocytes, we analyzed whether a killed bacterial suspension or its soluble polysaccharide (PS) could modulate the absolute number of peritoneal B-1 cells in BALB/c mice, the activation status of these cells and their ability to differentiate into phagocytes in vitro. In vivo, P. acnes treatment elevated the absolute number of all B-1 subsets, whereas PS only increased B-1c. Moreover, the bacterium increased the number of B-1b cells that were positive for MHC II, TLR2, TLR4, TLR9, IL-4, IL-5 and IL-12, in addition to up-regulating TLR9, CD80 and CD86 expression. PS increased B-1b cell expression of TLR4, TLR9, CD40 and CD86, as well as IL-10 and IL-12 synthesis. Both of the treatments decreased the absolute number of B-1b cells in vitro, suggesting their early differentiation into B-1 cell-derived phagocytes (B-1CDP). We also observed a higher phagocytic activity from the phagocytes that were derived from B-1b cells after P. acnes and PS treatment. The adjuvant effect that P. acnes has on B-1 cells, mainly the B-1b subtype, reinforces the importance of B-1 cells in the innate and adaptive immune responses.

Evaluation of Streptococcus pneumoniae Type XIV Opsonins by Phagocytosis-Associated Chemiluminescence and a Bactericidal Assay

PubMed Central

Gardner, Susan E.; Anderson, Donald C.; Webb, Bette J.; Stitzel, Ann E.; Edwards, Morven S.; Spitzer, Roger E.; Baker, Carol J.

1982-01-01

The relative roles of serum factors required for opsonization of type XIV Streptococcus pneumoniae were investigated by means of luminol-enhanced chemiluminescence (CL), bactericidal, and immunofluorescence assays employing adult sera containing high (>1,000 ng of antibody nitrogen per ml) or low (<200 ng of antibody nitrogen per ml) antibody concentrations as determined by radioimmunoassay. Specific antibody concentration correlated directly with both total and heat-labile CL activity (P < 0.005) and with the bactericidal index (P < 0.05) at a serum concentration of 10%. The importance of specific antibody as an opsonin was confirmed by the abolition of CL activity and immunoglobulin immunofluorescence observed after absorption of heated sera with type XIV pneumococcal cells and by the dose response in CL and bactericidal activity observed with the addition of immunoglobulin G to hypogammaglobulinemic serum. A role for the classical complement pathway in opsonization was indicated by significantly greater CL integrals for high-antibody sera than for low-antibody sera depleted of factor D and by the bactericidal activity noted for untreated, but not magnesium ethylene glycol-bis(β-aminoethyl ether)-N,N-tetraacetic acid-chelated low-antibody sera. The alternative pathway contributed more than half of the CL activity of both high- and low-antibody sera. However, after magnesium ethylene glycol-bis(β-aminoethyl ether)-N,N-tetraacetic acid chelation, only sera with high antibody concentrations or agammaglobulinemic serum reconstituted with immunoglobulin G with high specific antibody levels supported significant bactericidal activity. Therefore, type-specific antibody and complement promote opsonization of type XIV S. pneumoniae, and this may occur via either complement pathway. These results suggest that CL is a suitable tool to delineate serum factors and their contribution to opsonization, but results must be related to other functional assays. PMID:6802760

[Bactericidal effect of soybean peroxidase-hydrogen peroxide-potassium iodide system].

PubMed

Jin, Jianling; Zhang, Weican; Li, Yu; Zhao, Yue; Wang, Fei; Gao, Peiji

2011-03-01

To study the bactericidal effect and the possible mechanisms of the three components system [soybean peroxidases (SBP)-hydrogen peroxide (H2O2)-potassium iodide (KI), SBP-H2O2-KI]. The inhibition and bactericidal effect of SBP-H2O2-KI system to bacteria was detected by OD600 and the number of live bacteria (CFU). The sensitivity was tested by comparing the minimum inhibitory concentration (MIC) of bacterial cultures before and after cultured under sub-lethal dose of SBP-H2O2-KI system. Oxidizing activity groups were detected with physical and chemical methods in order to explain the bactericidal mechanisms of SBP-H2O2-KI system. SBP-H2O2-KI ternary system had rapid and high efficient bactericidal effect to a variety of bacterial strains in just several minutes. The MICs had no significant changes when bacterial cultures continuously cultured in sub-lethal dose of SBP-H2O2-KI system, and no resistance/tolerance mutant strains could be isolated from them. Both physical and chemical test results showed that no hydroxyl radical produced in SBP- H2O2-KI reaction system, chemical test results showed that no superoxide anion but a singlet oxygen and iodine produced in SBP-H2O2-KI reaction system. These results suggested that singlet oxygen and iodine or the iodine intermediate state may possible be the main sterilization factors for SBP-H2O2-KI system, and hydroxyl radical and superoxide anion not. In addition, the both characteristics of SBP-H2O2-KI system: rapid and high efficient bactericidal effect, and bacteria difficultly resisting to it, indicated it would have a good potential application in medical and plant protection area.

Bactericidal Effect of Photolysis of H2O2 in Combination with Sonolysis of Water via Hydroxyl Radical Generation.

PubMed

Sheng, Hong; Nakamura, Keisuke; Kanno, Taro; Sasaki, Keiichi; Niwano, Yoshimi

2015-01-01

The bactericidal effect of hydroxyl radical (·OH) generated by combination of photolysis of hydrogen peroxide (H2O2) and sonolysis of water was examined under the condition in which the yield of ·OH increased additively when H2O2 aqueous solution was concomitantly irradiated with laser and ultrasound. The suspension of Staphylococcus aureus mixed with the different concentrations of H2O2 was irradiated simultaneously with a laser light (wavelength: 405 nm, irradiance: 46 and 91 mW/cm2) and ultrasound (power: 30 w, frequency: 1.65 MHz) at 20 ± 1°C of the water bulk temperature for 2 min. The combination of laser and ultrasound irradiation significantly reduced the viable bacterial count in comparison with the laser irradiation of H2O2 alone. By contrast, the ultrasound irradiation alone exerted almost no bactericidal effect. These results suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity was synergistic. A multi-way analysis of variance also revealed that the interaction of H2O2 concentration, laser power and ultrasound irradiation significantly affected the bactericidal activity. Since the result of oxidative DNA damage evaluation demonstrated that the combination of laser and ultrasound irradiation significantly induced oxidative damage of bacterial DNA in comparison with the laser irradiation of H2O2 alone, it was suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity would be exerted via oxidative damage of cellular components such as DNA.

Role of caspofungin in restoring the impaired phagocyte-dependent innate immunity towards Candida albicans in chronic haemodialysis patients.

PubMed

Scalas, Daniela; Banche, Giuliana; Merlino, Chiara; Giacchino, Franca; Allizond, Valeria; Garneri, Giuseppe; Patti, Rosaria; Roana, Janira; Mandras, Narcisa; Tullio, Vivian; Cuffini, Anna Maria

2012-01-01

Phagocyte-dependent cellular immunity in chronic kidney disease patients undergoing haemodialysis treatment is frequently impaired owing to the uraemic state, resulting in an intrinsic susceptibility to developing invasive fungal infections with high mortality rates. Since synergism between phagocytic cells and antifungal drugs may be crucial for successful therapy, the aim of this study was to evaluate the effects exerted by caspofungin (CAS) on the functional activities of polymorphonuclear cells (PMNs) in haemodialysed patients (HDs) towards Candida albicans compared with those of PMNs from healthy subjects (HSs). PMNs were separated from venous blood samples of 66 HDs and 30 HSs (as controls), and measurement of phagocytic and intracellular fungicidal activities of HD-PMNs and HS-PMNs was performed in the presence of CAS at the minimum inhibitory concentration (MIC) and at sub-MICs. CAS-free controls were also included. In the drug-free test condition, no significant difference between the phagocytic activity of HD-PMNs and HS-PMNs was detected. In contrast, a progressive decline in the intracellular killing activity of HD-PMNs against proliferating yeasts was observed. CAS at MIC and sub-MIC levels was able to improve significantly the intracellular fungicidal activity of HD-PMNs against C. albicans, restoring their functionality. These findings provide evidence that CAS exerts a synergistic effect on HD-PMNs against C. albicans, being able to strength the depressed intracellular killing activity. These results corroborate the use of CAS as an effective therapeutic option for the treatment of invasive fungal infections in HDs, in whom even a marginal influence of antifungal drugs on host response may have a relevant effect. Copyright © 2011 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Diversity of Human and Macaque Airway Immune Cells at Baseline and during Tuberculosis Infection

PubMed Central

Myers, Amy J.; Jarvela, Jessica; Flynn, JoAnne; Rutledge, Tara; Bonfield, Tracey

2016-01-01

Immune cells of the distal airways serve as “first responders” of host immunity to the airborne pathogen Mycobacterium tuberculosis (Mtb). Mtb infection of cynomolgus macaques recapitulates the range of human outcomes from clinically silent latent tuberculosis infection (LTBI) to active tuberculosis of various degrees of severity. To further advance the application of this model to human studies, we compared profiles of bronchoalveolar lavage (BAL) cells of humans and cynomolgus macaques before and after Mtb infection. A simple gating strategy effectively defined BAL T-cell and phagocyte populations in both species. BAL from Mtb-naive humans and macaques showed similar differential cell counts. BAL T cells of macaques were composed of fewer CD4+cells but more CD8+ and CD4+CD8+ double-positive cells than were BAL T cells of humans. The most common mononuclear phagocyte population in BAL of both species displayed coexpression of HLA-DR, CD206, CD11b, and CD11c; however, multiple phagocyte subsets displaying only some of these markers were observed as well. Macaques with LTBI displayed a marked BAL lymphocytosis that was not observed in humans with LTBI. In macaques, the prevalence of specific mononuclear phagocyte subsets in baseline BAL correlated with ultimate outcomes of Mtb infection (i.e., LTBI versus active disease). Overall, these findings demonstrate the comparability of studies of pulmonary immunity to Mtb in humans and macaques. They also indicate a previously undescribed complexity of airway mononuclear phagocyte populations that suggests further lines of investigation relevant to understanding the mechanisms of both protection from and susceptibility to the development of active tuberculosis within the lung. PMID:27509488

Effect of single oral dose of azithromycin, clarithromycin, and roxithromycin on polymorphonuclear leukocyte function assessed ex vivo by flow cytometry.

PubMed Central

Wenisch, C; Parschalk, B; Zedtwitz-Liebenstein, K; Weihs, A; el Menyawi, I; Graninger, W

1996-01-01

Azithromycin was given as a single oral dose (20 mg/kg of body weight) to 12 volunteers in a crossover study with roxithromycin (8 to 12 mg/kg) and clarithromycin (8 to 12 mg/kg). Flow cytometry was used to study the phagocytic functions and the release of reactive oxygen products following phagocytosis by neutrophil granulocytes prior to administration of the three drugs, 16 h after azithromycin administration, and 3 h after clarithromycin and roxithromycin administration. Phagocytic capacity was assessed by measuring the uptake of fluorescein isothiocyanate-labeled bacteria. Reactive oxygen generation after phagocytosis of unlabeled bacteria was estimated by the amount of dihydrorhodamine 123 converted to rhodamine 123 intracellularly. Azithromycin resulted in decreased capacities of the cells to phagocytize Escherichia coli (median [range], 62% [27 to 91%] of the control values; P < 0.01) and generate reactive oxygen products (75% [34 to 26%] of the control values; P < 0.01). Clarithromycin resulted in reduced phagocytosis (82% [75 to 98%] of control values; P < 0.01) but did not alter reactive oxygen production (84% [63 to 113%] of the control values; P > 0.05). Roxithromycin treatment did not affect granulocyte phagocytosis (92% [62 to 118%] of the control values; P > 0.05) or reactive oxygen production (94% [66 to 128%] of the control value; P > 0.05). No relation between intra- and/or extracellular concentrations of azithromycin and/or roxithromycin and the polymorphonuclear phagocyte function and/or reactive oxygen production existed (P > 0.05 for all comparisons). These results demonstrate that the accumulation of macrolides in neutrophils can suppress the response of phagocytic cells to bacterial pathogens after a therapeutic dose. PMID:8878577

Investigating Evolutionary Conservation of Dendritic Cell Subset Identity and Functions

PubMed Central

Vu Manh, Thien-Phong; Bertho, Nicolas; Hosmalin, Anne; Schwartz-Cornil, Isabelle; Dalod, Marc

2015-01-01

Dendritic cells (DCs) were initially defined as mononuclear phagocytes with a dendritic morphology and an exquisite efficiency for naïve T-cell activation. DC encompass several subsets initially identified by their expression of specific cell surface molecules and later shown to excel in distinct functions and to develop under the instruction of different transcription factors or cytokines. Very few cell surface molecules are expressed in a specific manner on any immune cell type. Hence, to identify cell types, the sole use of a small number of cell surface markers in classical flow cytometry can be deceiving. Moreover, the markers currently used to define mononuclear phagocyte subsets vary depending on the tissue and animal species studied and even between laboratories. This has led to confusion in the definition of DC subset identity and in their attribution of specific functions. There is a strong need to identify a rigorous and consensus way to define mononuclear phagocyte subsets, with precise guidelines potentially applicable throughout tissues and species. We will discuss the advantages, drawbacks, and complementarities of different methodologies: cell surface phenotyping, ontogeny, functional characterization, and molecular profiling. We will advocate that gene expression profiling is a very rigorous, largely unbiased and accessible method to define the identity of mononuclear phagocyte subsets, which strengthens and refines surface phenotyping. It is uniquely powerful to yield new, experimentally testable, hypotheses on the ontogeny or functions of mononuclear phagocyte subsets, their molecular regulation, and their evolutionary conservation. We propose defining cell populations based on a combination of cell surface phenotyping, expression analysis of hallmark genes, and robust functional assays, in order to reach a consensus and integrate faster the huge but scattered knowledge accumulated by different laboratories on different cell types, organs, and species. PMID:26082777

Cellular immune responses and phagocytic activity of fishes exposed to pollution of volcano mud.

PubMed

Risjani, Yenny; Yunianta; Couteau, Jerome; Minier, Christophe

2014-05-01

Since May 29, 2006, a mud volcano in the Brantas Delta of the Sidoarjo district has emitted mud that has inundated nearby villages. Pollution in this area has been implicated in detrimental effects on fish health. In fishes, leukocyte and phagocytic cells play a vital role in body defenses. We report for the first time the effect of "LUSI" volcano mud on the immune systems of fish in the Brantas Delta. The aim of this study was to find biomarkers to allow the evaluation of the effects of volcanic mud and anthropogenic pollution on fish health in the Brantas Delta. The study took places at the Brantas Delta, which was polluted by volcano mud, and at reference sites in Karangkates and Pasuruan. Leukocyte numbers were determined using a Neubauer hemocytometer and a light microscope. Differential leukocyte counts were determined using blood smears stained with May Grunwald-Giemsa, providing neutrophil, lymphocyte and monocyte counts. Macrophages were taken from fish kidney, and their phagocytic activity was measured. In vitro analyses revealed that leukocyte and differential leukocyte counts (DLC) were higher in Channa striata and Chanos chanos caught from the polluted area. Macrophage numbers were higher in Oreochromis mossambicus than in the other species, indicating that this species is more sensitive to pollution. In areas close to volcanic mud eruption, all specimens had lower phagocytic activity. Our results show that immune cells were changed and phagocytic activity was reduced in the polluted area indicating cytotoxicity and alteration of the innate immune system in fishes exposed to LUSI volcano mud and anthropogenic pollution. Copyright © 2014 Elsevier Ltd. All rights reserved.

Elevated Mitochondrial Reactive Oxygen Species and Cellular Redox Imbalance in Human NADPH-Oxidase-Deficient Phagocytes

PubMed Central

Sundqvist, Martina; Christenson, Karin; Björnsdottir, Halla; Osla, Veronica; Karlsson, Anna; Dahlgren, Claes; Speert, David P.; Fasth, Anders; Brown, Kelly L.; Bylund, Johan

2017-01-01

Chronic granulomatous disease (CGD) is caused by mutations in genes that encode the NADPH-oxidase and result in a failure of phagocytic cells to produce reactive oxygen species (ROS) via this enzyme system. Patients with CGD are highly susceptible to infections and often suffer from inflammatory disorders; the latter occurs in the absence of infection and correlates with the spontaneous production of inflammatory cytokines. This clinical feature suggests that NADPH-oxidase-derived ROS are not required for, or may even suppress, inflammatory processes. Experimental evidence, however, implies that ROS are in fact required for inflammatory cytokine production. By using a myeloid cell line devoid of a functional NADPH-oxidase and primary CGD cells, we analyzed intracellular oxidants, signs of oxidative stress, and inflammatory cytokine production. Herein, we demonstrate that phagocytes lacking a functional NADPH-oxidase, namely primary CGD phagocytes and a gp91phox-deficient cell line, display elevated levels of ROS derived from mitochondria. Accordingly, these cells, despite lacking the major source of cellular ROS, display clear signs of oxidative stress, including an induced expression of antioxidants and altered oxidation of cell surface thiols. These observed changes in redox state were not due to abnormalities in mitochondrial mass or membrane integrity. Finally, we demonstrate that increased mitochondrial ROS enhanced phosphorylation of ERK1/2, and induced production of IL8, findings that correlate with previous observations of increased MAPK activation and inflammatory cytokine production in CGD cells. Our data show that elevated baseline levels of mitochondria-derived oxidants lead to the counter-intuitive observation that CGD phagocytes are under oxidative stress and have enhanced MAPK signaling, which may contribute to the elevated basal production of inflammatory cytokines and the sterile inflammatory manifestations in CGD. PMID:29375548

A privileged intraphagocyte niche is responsible for disseminated infection of Staphylococcus aureus in a zebrafish model

PubMed Central

Prajsnar, Tomasz K; Hamilton, Ruth; Garcia-Lara, Jorge; McVicker, Gareth; Williams, Alexander; Boots, Michael; Foster, Simon J; Renshaw, Stephen A

2012-01-01

The innate immune system is the primary defence against the versatile pathogen, Staphylococcus aureus. How this organism is able to avoid immune killing and cause infections is poorly understood. Using an established larval zebrafish infection model, we have shown that overwhelming infection is due to subversion of phagocytes by staphylococci, allowing bacteria to evade killing and found foci of disease. Larval zebrafish coinfected with two S. aureus strains carrying different fluorescent reporter gene fusions (but otherwise isogenic) had bacterial lesions, at the time of host death, containing predominantly one strain. Quantitative data using two marked strains revealed that the strain ratios, during overwhelming infection, were often skewed towards the extremes, with one strain predominating. Infection with passaged bacterial clones revealed the phenomenon not to bedue to adventitious mutations acquired by the pathogen. After infection of the host, all bacteria are internalized by phagocytes and the skewing of population ratios is absolutely dependent on the presence of phagocytes. Mathematical modelling of pathogen population dynamics revealed the data patterns are consistent with the hypothesis that a small number of infected phagocytes serve as an intracellular reservoir for S. aureus, which upon release leads to disseminated infection. Strategies to specifically alter neutrophil/macrophage numbers were used to map the potential subpopulation of phagocytes acting as a pathogen reservoir, revealing neutrophils as the likely ‘niche’. Subsequently in a murine sepsis model, S. aureus abscesses in kidneys were also found to be predominantly clonal, therefore likely founded by an individual cell, suggesting a potential mechanism analogous to the zebrafish model with few protected niches. These findings add credence to the argument that S. aureus control regimes should recognize both the intracellular as well as extracellular facets of the S. aureus life cycle. PMID:22694745

Preliminary flight prototype potable water bactericide system

NASA Technical Reports Server (NTRS)

Jasionowski, W. J.; Allen, E. T.

1973-01-01

The development, design, and testing of a preliminary flight prototype potable water bactericide system are described. The system is an assembly of upgraded canisters composed of: (1) A biological filter; (2) an activated charcoal and ion exchange resin canister; (3) a silver chloride canister, (4) a deionizer, (5) a silver bromide canister with a partial bypass, and (6) mock-up instrumentation and circuitry. The system exhibited bactericidal activity against 10 to the 9th power Pseudomonas aeruginosa and/or Type IIIa, and reduced Bacillus subtilis by up to 5 orders of magnitude in 24 hours at ambient temperatures with a 1 ppm silver ion dose. Four efficacy tests were performed with a AgBr canister dosing anticipated fuel cell water. Tests show that a 0.05 ppm silver ion dose was bactericidal against 3 plus or minus 1 x 10 to the 9th power (5 plus or minus 1 x 10,000/ml Pseudomonas aeruginosa and/or Type IIIa in 15 minutes or less.

Influence of Scaffold Size on Bactericidal Activity of Nitric Oxide Releasing Silica Nanoparticles

PubMed Central

Carpenter, Alexis W.; Slomberg, Danielle L.; Rao, Kavitha S.; Schoenfisch, Mark H.

2011-01-01

A reverse microemulsion synthesis was used to prepare amine functionalized silica nanoparticles of three distinct sizes (i.e., 50, 100, and 200 nm) with identical amine concentrations. The resulting hybrid nanoparticles, consisting of N-(6 aminohexyl) aminopropyltrimethoxysilane and tetraethoxysilane, were highly monodisperse in size. N-diazeniumdiolate nitric oxide (NO) donors were subsequently formed on secondary amines while controlling reaction conditions to keep the total amount of nitric oxide (NO) released constant for each particle size. The bactericidal efficacy of the NO releasing nanoparticles against Pseudomonas aeruginosa increased with decreasing particle size. Additionally, smaller diameter nanoparticles were found to associate with the bacteria at a faster rate and to a greater extent than larger particles. Neither control (non-NO-releasing) nor NO releasing particles exhibited toxicity towards L929 mouse fibroblasts at concentrations above their respective minimum bactericidal concentrations. This study represents the first investigation of the bactericidal efficacy of NO-releasing silica nanoparticles as a function of particle size. PMID:21842899

In vitro modification of Candida albicans invasiveness.

PubMed

Fontenla de Petrino, S E; de Jorrat, M E; Sirena, A; Valdez, J C; Mesón, O

1986-05-01

Candida albicans produces germ-tubes (GT) when it is incubated in animal or human serum. This dimorphism is responsible for its invasive ability. The purpose of the present paper is (1) to evaluate the ability of rat peritoneal macrophages to inhibit GT production of ingested Candida albicans, obtained from immunized rats and then activated in vitro with Candida-induced lymphokines; (2) to determinate any possible alteration of phagocytic and candidacidal activities. The phagocytes were obtained from rats immunized with viable C. albicans. Some of them were exposed to Candida-induced lymphokines in order to activate the macrophages in vitro. The monolayers of activated, immune and normal macrophages were infected with a C. albicans suspension during 4 hr. Activated macrophages presented not only the highest phagocytic and candidacidal activities but a noticeable inhibition of GT formation and incremented candidacidal activity.

Staphylococcus aureus synthesizes adenosine to escape host immune responses

PubMed Central

Thammavongsa, Vilasack; Kern, Justin W.; Missiakas, Dominique M.

2009-01-01

Staphylococcus aureus infects hospitalized or healthy individuals and represents the most frequent cause of bacteremia, treatment of which is complicated by the emergence of methicillin-resistant S. aureus. We examined the ability of S. aureus to escape phagocytic clearance in blood and identified adenosine synthase A (AdsA), a cell wall–anchored enzyme that converts adenosine monophosphate to adenosine, as a critical virulence factor. Staphylococcal synthesis of adenosine in blood, escape from phagocytic clearance, and subsequent formation of organ abscesses were all dependent on adsA and could be rescued by an exogenous supply of adenosine. An AdsA homologue was identified in the anthrax pathogen, and adenosine synthesis also enabled escape of Bacillus anthracis from phagocytic clearance. Collectively, these results suggest that staphylococci and other bacterial pathogens exploit the immunomodulatory attributes of adenosine to escape host immune responses. PMID:19808256

Mononuclear Phagocyte-Mediated Antifungal Immunity: The Role of Chemotactic Receptors and Ligands

PubMed Central

Swamydas, Muthulekha; Break, Timothy J.; Lionakis, Michail S.

2015-01-01

Over the past two decades, fungal infections have emerged as significant causes of morbidity and mortality in patients with hematological malignancies, hematopoietic stem cell or solid organ transplantation and acquired immunodeficiency syndrome. Besides neutrophils and CD4+ T lymphocytes, which have long been known to play an indispensable role in promoting protective antifungal immunity, mononuclear phagocytes are now being increasingly recognized as critical mediators of host defense against fungi. Thus, a recent surge of research studies has focused on understanding the mechanisms by which resident and recruited monocytes, macrophages and dendritic cells accumulate and become activated at the sites of fungal infection. Herein, we critically review how a variety of G-protein coupled chemoattractant receptors and their ligands mediate mononuclear phagocyte recruitment and effector function during infection by the most common human fungal pathogens. PMID:25715741

Bactericidal activity of propylene glycol, glycerine, polyethylene glycol 400, and polyethylene glycol 1000 against selected microorganisms

PubMed Central

Nalawade, Triveni Mohan; Bhat, Kishore; Sogi, Suma H. P.

2015-01-01

Aim: The aim of the present study was to evaluate the bactericidal activity of propylene glycol, glycerine, polyethylene glycol 400 (PEG 400), and polyethylene glycol 1000 (PEG 1000) against selected microorganisms in vitro. Materials and Methods: Five vehicles, namely propylene glycol, glycerine, PEG 400, PEG 1000, and combination of propylene glycol with PEG 400, were tested for their bactericidal activity. The minimum bactericidal concentration was noted against four standard strains of organisms, i.e. Streptococcus mutans American Type Culture Collection (ATCC) 25175, Streptococcus mutans ATCC 12598, Enterococcus faecalis ATCC 35550, and Escherichia coli ATCC 25922, using broth dilution assay. Successful endodontic therapy depends upon thorough disinfection of root canals. In some refractory cases, routine endodontic therapy is not sufficient, so intracanal medicaments are used for proper disinfection of canals. Intracanal medicaments are dispensed with vehicles which aid in increased diffusion through the dentinal tubules and improve their efficacy. Among the various vehicles used, glycerine is easily available, whereas others like propylene glycol and polyethylene glycol have to be procured from appropriate sources. Also, these vehicles, being viscous, aid in sustained release of the medicaments and improve their handling properties. The most commonly used intracanal medicaments like calcium hydroxide are ineffective on many microorganisms, while most of the other medicaments like MTAD (Mixture of Tetracycline, an Acid, and a Detergent) and Triple Antibiotic Paste (TAP) consist of antibiotics which can lead to development of antibiotic resistance among microorganisms. Thus, in order to use safer and equally effective intracanal medicaments, newer alternatives like chlorhexidine gluconate, ozonized water, etc., are being explored. Similarly, the five vehicles mentioned above are being tested for their antimicrobial activity in this study. Results: All vehicles exhibited bactericidal activity at 100% concentration. Conclusion: Propylene glycol was effective against three organisms namely S. mutans E. faecalis and E. coli and its bactericidal activity was at 50%, 25% and 50% respectively. PEG 1000 was effective against S. mutans and E. coli at 25%. Hence propylene glycol was effective on more number of organisms of which E. faecalis is a known resistant species. PEG 1000 was bactericidal at a lower concentration but was effective on two organisms only. PMID:25992336

Bactericidal activity of propylene glycol, glycerine, polyethylene glycol 400, and polyethylene glycol 1000 against selected microorganisms.

PubMed

Nalawade, Triveni Mohan; Bhat, Kishore; Sogi, Suma H P

2015-01-01

The aim of the present study was to evaluate the bactericidal activity of propylene glycol, glycerine, polyethylene glycol 400 (PEG 400), and polyethylene glycol 1000 (PEG 1000) against selected microorganisms in vitro. Five vehicles, namely propylene glycol, glycerine, PEG 400, PEG 1000, and combination of propylene glycol with PEG 400, were tested for their bactericidal activity. The minimum bactericidal concentration was noted against four standard strains of organisms, i.e. Streptococcus mutans American Type Culture Collection (ATCC) 25175, Streptococcus mutans ATCC 12598, Enterococcus faecalis ATCC 35550, and Escherichia coli ATCC 25922, using broth dilution assay. Successful endodontic therapy depends upon thorough disinfection of root canals. In some refractory cases, routine endodontic therapy is not sufficient, so intracanal medicaments are used for proper disinfection of canals. Intracanal medicaments are dispensed with vehicles which aid in increased diffusion through the dentinal tubules and improve their efficacy. Among the various vehicles used, glycerine is easily available, whereas others like propylene glycol and polyethylene glycol have to be procured from appropriate sources. Also, these vehicles, being viscous, aid in sustained release of the medicaments and improve their handling properties. The most commonly used intracanal medicaments like calcium hydroxide are ineffective on many microorganisms, while most of the other medicaments like MTAD (Mixture of Tetracycline, an Acid, and a Detergent) and Triple Antibiotic Paste (TAP) consist of antibiotics which can lead to development of antibiotic resistance among microorganisms. Thus, in order to use safer and equally effective intracanal medicaments, newer alternatives like chlorhexidine gluconate, ozonized water, etc., are being explored. Similarly, the five vehicles mentioned above are being tested for their antimicrobial activity in this study. All vehicles exhibited bactericidal activity at 100% concentration. Propylene glycol was effective against three organisms namely S. mutans E. faecalis and E. coli and its bactericidal activity was at 50%, 25% and 50% respectively. PEG 1000 was effective against S. mutans and E. coli at 25%. Hence propylene glycol was effective on more number of organisms of which E. faecalis is a known resistant species. PEG 1000 was bactericidal at a lower concentration but was effective on two organisms only.

Powerful bacterial killing by buckwheat honeys is concentration-dependent, involves complete DNA degradation and requires hydrogen peroxide.

PubMed

Brudzynski, Katrina; Abubaker, Kamal; Wang, Tony

2012-01-01

Exposure of bacterial cells to honey inhibits their growth and may cause cell death. Our previous studies showed a cause-effect relationship between hydroxyl radical generated from honey hydrogen peroxide and growth arrest. Here we explored the role of hydroxyl radicals as inducers of bacterial cells death. The bactericidal effect of ·OH on antibiotic-resistant clinical isolates of MRSA and VRE and standard bacterial strains of E. coli and B. subtiles was examined using a broth microdilution assay supplemented with 3'-(p-aminophenyl) fluorescein (APF) as the ·OH trap, followed by colony enumeration. Bactericidal activities of eight honeys (six varieties of buckwheat, blueberry and manuka honeys) were analyzed. The MBC/MIC ratio ≤4 and the killing curves indicated that honeys exhibited powerful, concentration-dependent bactericidal effect. The extent of killing depended on the ratio of honey concentration to bacterial load, indicating that honey dose was critical for its bactericidal efficacy. The killing rate and potency varied between honeys and ranged from over a 6-log(10) to 4-log(10) CFU/ml reduction of viable cells, equivalent to complete bacterial eradication. The maximal killing was associated with the extensive degradation of bacterial DNA. Honey concentration at which DNA degradation occurred correlated with cell death observed in the concentration-dependent cell-kill on agar plates. There was no quantitative relationship between the ·OH generation by honey and bactericidal effect. At the MBC, where there was no surviving cells and no DNA was visible on agarose gels, the ·OH levels were on average 2-3x lower than at Minimum Inhibitory Concentration (MICs) (p < 0.0001). Pre-treatment of honey with catalase, abolished the bactericidal effect. This raised possibilities that either the abrupt killing prevented accumulation of ·OH (dead cells did not generate ·OH) or that DNA degradation and killing is the actual footprint of ·OH action. In conclusion, honeys of buckwheat origin exhibited powerful, concentration-dependent bactericidal effect. The killing and DNA degradation showed a cause-effect relationship. Hydrogen peroxide was an active part of honey killing mechanism.

In vitro bactericidal and bacteriolytic activity of ceragenin CSA-13 against planktonic cultures and biofilms of Streptococcus pneumoniae and other pathogenic streptococci.

PubMed

Moscoso, Miriam; Esteban-Torres, María; Menéndez, Margarita; García, Ernesto

2014-01-01

Ceragenin CSA-13, a cationic steroid, is here reported to show a concentration-dependent bactericidal/bacteriolytic activity against pathogenic streptococci, including multidrug-resistant Streptococcus pneumoniae. The autolysis promoted by CSA-13 in pneumococcal cultures appears to be due to the triggering of the major S. pneumoniae autolysin LytA, an N-acetylmuramoyl-L-alanine amidase. CSA-13 also disintegrated pneumococcal biofilms in a very efficient manner, although at concentrations slightly higher than those required for bactericidal activity on planktonic bacteria. CSA-13 has little hemolytic activity which should allow testing its antibacterial efficacy in animal models.

Intradermal reactions to purified protein derivative in patients with diabetes mellitus.

PubMed

Nwabudike, L C; Ionescu-Tîrgovişte, C

2005-01-01

Diabetes mellitus is known to adversely affect the immune system. Immune dysfunction is also associated with the etiology of diabetes mellitus. Immune dysfunction is associated with diminished chemotactic, phagocytic and monocyte activity. There is also increased T-cell activity. All these are associated with acute hyperglycemia. We investigated the cellular arm of the immune system of patients with diabetes mellitus using intradermal reactions (IDR) to purified protein derivative (PPD). Both groups high blood glucose [HBG] vs. low blood glucose [LBG]) were homogeneous in terms of size and sex and average age (24. vs. 22.; 21 F vs 25 M; 56.5yrs. vs. 54.5 yrs.). The LBG had a greater average duration of diabetes (13.6 yrs vs. 9.3 yrs), which suggests an increased tendency to complications of diabetes mellitus. The results showed an average blood glucose and IDR (HBG vs. LBG) of 235.8 +/- 46.5 mg/dl vs. 144.3 +/- 26.7 mg/dl and 18.5 +/- 8.5 mm vs. 12.2 +/- 7.0 mm respectively. These results showed that IDR is significantly affected by hyperglycemia. This increased IDR may be a consequence of the synergy between interferon-gamma and tumor necrosis factor alpha which is a significant factor in diabetes. Also, there is an accentuation of this synergy following injection of PPD. It appears to be clear that IDR to PPD may be influenced by the diabetic state, especially acute hyperglycemia. However, it also appears that IDR to PPD may not be an adequate method for assessing cutaneous cell-mediated immunity.

Magnetic Nanoparticle-Based Imaging of RNA Transcripts in Breast Cancer Cells

DTIC Science & Technology

2008-06-30

control (Months 33 – 36). These studies have not yet commenced. KEY RESEARCH ACCOMPLISHMENTS: - Synthesized dextran-coated iron oxide NPs with...Size, charge, and concentration dependent uptake of iron oxide nanoparticles by non-phagocytic cells: a comparative study of USPIO, SSPIO, and MPIO...A. (2008) Size, charge, and concentration dependent uptake of iron oxide nanoparticles by non-phagocytic cells: a comparative study of USPIO, SSPIO

[Formation of endogenous pyrogen by mononuclear phagocytes].

PubMed

Agasarov, L G; Sorokin, A V; Ukhanova, I K

1984-07-01

Production of endogenous pyrogen by human and rabbit blood monocytes in response to stimulation with agents of different origin was studied by inhibitory analysis under comparable conditions. Actinomycin D and cytochalasin B were applied. New evidence was obtained about an important role in the mechanism of activation of mononuclear phagocytes of initial interaction between a stimulating agent and the leukocyte membrane and of the biphasic process of endogenous pyrogen production.

Nano-sized and micro-sized polystyrene particles affect phagocyte function

PubMed Central

Prietl, B.; Meindl, C.; Roblegg, E.; Pieber, T. R.; Lanzer, G.; Fröhlich, E.

2015-01-01

Adverse effect of nanoparticles may include impairment of phagocyte function. To identify the effect of nanoparticle size on uptake, cytotoxicity, chemotaxis, cytokine secretion, phagocytosis, oxidative burst, nitric oxide production and myeloperoxidase release, leukocytes isolated from human peripheral blood, monocytes and macrophages were studied. Carboxyl polystyrene (CPS) particles in sizes between 20 and 1,000 nm served as model particles. Twenty nanometers CPS particles were taken up passively, while larger CPS particles entered cells actively and passively. Twenty nanometers CPS were cytotoxic to all phagocytes, ≥500 nm CPS particles only to macrophages. Twenty nanometers CPS particles stimulated IL-8 secretion in human monocytes and induced oxidative burst in monocytes. Five hundred nanometers and 1,000 nm CPS particles stimulated IL-6 and IL-8 secretion in monocytes and macrophages, chemotaxis towards a chemotactic stimulus of monocytes and phagocytosis of bacteria by macrophages and provoked an oxidative burst of granulocytes. At very high concentrations, CPS particles of 20 and 500 nm stimulated myeloperoxidase release of granulocytes and nitric oxide generation in macrophages. Cytotoxic effect could contribute to some of the observed effects. In the absence of cytotoxicity, 500 and 1,000 nm CPS particles appear to influence phagocyte function to a greater extent than particles in other sizes. PMID:24292270

Agent-based modeling approach of immune defense against spores of opportunistic human pathogenic fungi.

PubMed

Tokarski, Christian; Hummert, Sabine; Mech, Franziska; Figge, Marc Thilo; Germerodt, Sebastian; Schroeter, Anja; Schuster, Stefan

2012-01-01

Opportunistic human pathogenic fungi like the ubiquitous fungus Aspergillus fumigatus are a major threat to immunocompromised patients. An impaired immune system renders the body vulnerable to invasive mycoses that often lead to the death of the patient. While the number of immunocompromised patients is rising with medical progress, the process, and dynamics of defense against invaded and ready to germinate fungal conidia are still insufficiently understood. Besides macrophages, neutrophil granulocytes form an important line of defense in that they clear conidia. Live imaging shows the interaction of those phagocytes and conidia as a dynamic process of touching, dragging, and phagocytosis. To unravel strategies of phagocytes on the hunt for conidia an agent-based modeling approach is used, implemented in NetLogo. Different modes of movement of phagocytes are tested regarding their clearing efficiency: random walk, short-term persistence in their recent direction, chemotaxis of chemokines excreted by conidia, and communication between phagocytes. While the short-term persistence hunting strategy turned out to be superior to the simple random walk, following a gradient of chemokines released by conidial agents is even better. The advantage of communication between neutrophilic agents showed a strong dependency on the spatial scale of the focused area and the distribution of the pathogens.

Spores of two probiotic Bacillus species enhance cellular immunity in BALB/C mice.

PubMed

Gong, Li; Huang, Qin; Fu, Aikun; Wu, YanPing; Li, Yali; Xu, Xiaogang; Huang, Yi; Yu, Dongyou; Li, Weifen

2018-01-01

Previous studies found that Bacillus subtilis BS02 and B. subtilis subsp. natto BS04 isolated in our laboratory could activate the immune response of murine macrophages in vitro. This study aims to investigate the effects of dietary supplementation with Bacillus species spores on the systemic cellular immune response in BALB/C mice. Results showed that both B. subtilis BS02 and B. subtilis natto BS04 enhanced the phagocytic function of the mononuclear phagocyte system (MPS) and the cytotoxicity of natural killer (NK) cells. In addition, B. subtilis BS02 could increase the respiratory burst activity of blood phagocytes. Furthermore, B. subtilis BS02 and B. subtilis natto BS04 increased the percentage of gamma-interferon-producing CD4 + cells and CD8 + T-cells, but only BS04 increased the percentage of CD3 + cells and CD3 +  CD4 + cells in splenocytes. However, there were no effects on other subsets of splenic lymphocytes and mitogen-induced splenic lymphocyte proliferation. All data suggested that oral administration of B. subtilis BS02 or B. subtilis natto BS04 could significantly enhance cellular immunity in BALB/C mice by increasing phagocytic activity of MPS and cytotoxic activity of NK cells in a strain-specific manner.

Beta-1,3-1,6-glucan modulate the non-specific immune response to enhance the survival in the Vibrio alginolyticus infection of Taiwan abalone (Haliotis diversicolor supertexta).

PubMed

Wu, Yu-Sheng; Tseng, Tzu-Yu; Nan, Fan-Hua

2016-07-01

This research aims to investigate the non-specific immune response of Taiwan abalone (Haliotis diversicolor supertexta) which was treated with the beta-1,3-1,6-glucan to be observed in the survival impact after the Vibrio alginolyticus infection. The non-specific immune and physiological response of superoxide anion radical (O2(-)), phenoloxidase (PO), phagocytic index (PI), phagocytic rate (PR) and lucigenin-chemiluminescence for reactive oxygen intermediates (ROIs) were enhanced via in-vitro experiment. In the in-vivo experiment, the observed data presented that the haemolymph lysate supernatant (HLS), superoxide dismutase (SOD), glutamate oxalacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) were not significant enhanced, but the total haemocyte count (THC), O2(-), PO, phagocytic index (PI), phagocytic ratio (PR) and other parameters of immune were significantly promoted after treated with beta-1,3-1,6-glucan. In the challenge experiment, the survival rates of abalone in the 40 and 80 μl/ml groups of beta-1,3-1,6-glucan were observed from 6.67% up to 33.33% and 36.67% after injection with Vibrio alginolyticus, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

Flagellar motility is a key determinant of the magnitude of the inflammasome response to Pseudomonas aeruginosa.

PubMed

Patankar, Yash R; Lovewell, Rustin R; Poynter, Matthew E; Jyot, Jeevan; Kazmierczak, Barbara I; Berwin, Brent

2013-06-01

We previously demonstrated that bacterial flagellar motility is a fundamental mechanism by which host phagocytes bind and ingest bacteria. Correspondingly, loss of bacterial motility, consistently observed in clinical isolates from chronic Pseudomonas aeruginosa infections, enables bacteria to evade association and ingestion of P. aeruginosa by phagocytes both in vitro and in vivo. Since bacterial interactions with the phagocyte cell surface are required for type three secretion system-dependent NLRC4 inflammasome activation by P. aeruginosa, we hypothesized that reduced bacterial association with phagocytes due to loss of bacterial motility, independent of flagellar expression, will lead to reduced inflammasome activation. Here we report that inflammasome activation is reduced in response to nonmotile P. aeruginosa. Nonmotile P. aeruginosa elicits reduced IL-1β production as well as caspase-1 activation by peritoneal macrophages and bone marrow-derived dendritic cells in vitro. Importantly, nonmotile P. aeruginosa also elicits reduced IL-1β levels in vivo in comparison to those elicited by wild-type P. aeruginosa. This is the first demonstration that loss of bacterial motility results in reduced inflammasome activation and antibacterial IL-1β host response. These results provide a critical insight into how the innate immune system responds to bacterial motility and, correspondingly, how pathogens have evolved mechanisms to evade the innate immune system.

Flagellar Motility Is a Key Determinant of the Magnitude of the Inflammasome Response to Pseudomonas aeruginosa

PubMed Central

Patankar, Yash R.; Lovewell, Rustin R.; Poynter, Matthew E.; Jyot, Jeevan; Kazmierczak, Barbara I.

2013-01-01

We previously demonstrated that bacterial flagellar motility is a fundamental mechanism by which host phagocytes bind and ingest bacteria. Correspondingly, loss of bacterial motility, consistently observed in clinical isolates from chronic Pseudomonas aeruginosa infections, enables bacteria to evade association and ingestion of P. aeruginosa by phagocytes both in vitro and in vivo. Since bacterial interactions with the phagocyte cell surface are required for type three secretion system-dependent NLRC4 inflammasome activation by P. aeruginosa, we hypothesized that reduced bacterial association with phagocytes due to loss of bacterial motility, independent of flagellar expression, will lead to reduced inflammasome activation. Here we report that inflammasome activation is reduced in response to nonmotile P. aeruginosa. Nonmotile P. aeruginosa elicits reduced IL-1β production as well as caspase-1 activation by peritoneal macrophages and bone marrow-derived dendritic cells in vitro. Importantly, nonmotile P. aeruginosa also elicits reduced IL-1β levels in vivo in comparison to those elicited by wild-type P. aeruginosa. This is the first demonstration that loss of bacterial motility results in reduced inflammasome activation and antibacterial IL-1β host response. These results provide a critical insight into how the innate immune system responds to bacterial motility and, correspondingly, how pathogens have evolved mechanisms to evade the innate immune system. PMID:23529619

Immunomodulatory effect of ganoderma lucidum polysaccharides (GLP) on long-term heavy-load exercising mice.

PubMed

Shi, Yali; Cai, Dehua; Wang, Xiaojie; Liu, Xinshen

2012-12-01

Long-term heavy-load exercise can lead to a decrease in the organism's immune response. In this study, we used 100 Kunming (KM) mice to investigate the immune-regulatory effects of Ganoderma lucidum polysaccharides (GLP) on long-term heavy-load exercising mice. Peripheral white blood cells (WBC), the absolute value of neutrophils (NEUT), the phagocytic function of macrophages, serum agglutination valence, and the number of plaque-forming cells (PFC) were evaluated 4 weeks after gavaging long-term heavy-load exercising mice with GLP. After exercise, the WBC count in peripheral blood, absolute neutrophil count, macrophage phagocytic index, serum agglutination valence, and the number of plaque-forming cells were significantly reduced in the mice not fed GLP. Both medium and high doses of GLP drastically increased peripheral WBC, absolute neutrophil count, macrophage phagocytic index, serum agglutination valence, and the number of plaque-forming cells in long-term heavy-load exercising mice. High doses of GLP increased peritoneal macrophage phagocytic rate considerably. With this study, we demonstrate that 4 weeks of heavy-load exercise can lead to exercise-induced immunosuppression in mice. A supplement of GLP fed to these mice improves both non-specific and specific immune responses among these mice. The effect for the high-dose GLP treatment is especially significant.

Nano-sized and micro-sized polystyrene particles affect phagocyte function.

PubMed

Prietl, B; Meindl, C; Roblegg, E; Pieber, T R; Lanzer, G; Fröhlich, E

2014-02-01

Adverse effect of nanoparticles may include impairment of phagocyte function. To identify the effect of nanoparticle size on uptake, cytotoxicity, chemotaxis, cytokine secretion, phagocytosis, oxidative burst, nitric oxide production and myeloperoxidase release, leukocytes isolated from human peripheral blood, monocytes and macrophages were studied. Carboxyl polystyrene (CPS) particles in sizes between 20 and 1,000 nm served as model particles. Twenty nanometers CPS particles were taken up passively, while larger CPS particles entered cells actively and passively. Twenty nanometers CPS were cytotoxic to all phagocytes, ≥500 nm CPS particles only to macrophages. Twenty nanometers CPS particles stimulated IL-8 secretion in human monocytes and induced oxidative burst in monocytes. Five hundred nanometers and 1,000 nm CPS particles stimulated IL-6 and IL-8 secretion in monocytes and macrophages, chemotaxis towards a chemotactic stimulus of monocytes and phagocytosis of bacteria by macrophages and provoked an oxidative burst of granulocytes. At very high concentrations, CPS particles of 20 and 500 nm stimulated myeloperoxidase release of granulocytes and nitric oxide generation in macrophages. Cytotoxic effect could contribute to some of the observed effects. In the absence of cytotoxicity, 500 and 1,000 nm CPS particles appear to influence phagocyte function to a greater extent than particles in other sizes.

Comprehensive analysis of mouse retinal mononuclear phagocytes.

PubMed

Lückoff, Anika; Scholz, Rebecca; Sennlaub, Florian; Xu, Heping; Langmann, Thomas

2017-06-01

The innate immune system is activated in a number of degenerative and inflammatory retinal disorders such as age-related macular degeneration (AMD). Retinal microglia, choroidal macrophages, and recruited monocytes, collectively termed 'retinal mononuclear phagocytes', are critical determinants of ocular disease outcome. Many publications have described the presence of these cells in mouse models for retinal disease; however, only limited aspects of their behavior have been uncovered, and these have only been uncovered using a single detection method. The workflow presented here describes a comprehensive analysis strategy that allows characterization of retinal mononuclear phagocytes in vivo and in situ. We present standardized working steps for scanning laser ophthalmoscopy of microglia from MacGreen reporter mice (mice expressing the macrophage colony-stimulating factor receptor GFP transgene throughout the mononuclear phagocyte system), quantitative analysis of Iba1-stained retinal sections and flat mounts, CD11b-based retinal flow cytometry, and qRT-PCR analysis of key microglia markers. The protocol can be completed within 3 d, and we present data from retinas treated with laser-induced choroidal neovascularization (CNV), bright white-light exposure, and Fam161a-associated inherited retinal degeneration. The assays can be applied to any of the existing mouse models for retinal disorders and may be valuable for documenting immune responses in studies for immunomodulatory therapies.

The Staphylococcus aureus polysaccharide capsule and Efb-dependent fibrinogen shield act in concert to protect against phagocytosis

PubMed Central

Kuipers, Annemarie; Stapels, Daphne A. C.; Weerwind, Lleroy T.; Ko, Ya-Ping; Ruyken, Maartje; Lee, Jean C.; van Kessel, Kok P. M.

2016-01-01

Staphylococcus aureus has developed many mechanisms to escape from human immune responses. To resist phagocytic clearance, S. aureus expresses a polysaccharide capsule, which effectively masks the bacterial surface and surface-associated proteins, such as opsonins, from recognition by phagocytic cells. Additionally, secretion of the extracellular fibrinogen binding protein (Efb) potently blocks phagocytic uptake of the pathogen. Efb creates a fibrinogen shield surrounding the bacteria by simultaneously binding complement C3b and fibrinogen at the bacterial surface. By means of neutrophil phagocytosis assays with fluorescently labelled encapsulated serotype 5 (CP5) and serotype 8 (CP8) strains we compare the immune-modulating function of these shielding mechanisms. The data indicate that, in highly encapsulated S. aureus strains, the polysaccharide capsule is able to prevent phagocytic uptake at plasma concentrations <10 %, but loses its protective ability at higher concentrations of plasma. Interestingly, Efb shows a strong inhibitory effect on both capsule-negative and encapsulated strains at all tested plasma concentrations. Furthermore, the results suggest that both shielding mechanisms can exist simultaneously and collaborate to provide optimal protection against phagocytosis at a broad range of plasma concentrations. As opsonizing antibodies will be shielded from recognition by either mechanism, incorporating both capsular polysaccharides and Efb in future vaccines could be of great importance. PMID:27112346

The Staphylococcus aureus polysaccharide capsule and Efb-dependent fibrinogen shield act in concert to protect against phagocytosis.

PubMed

Kuipers, Annemarie; Stapels, Daphne A C; Weerwind, Lleroy T; Ko, Ya-Ping; Ruyken, Maartje; Lee, Jean C; van Kessel, Kok P M; Rooijakkers, Suzan H M

2016-07-01

Staphylococcus aureus has developed many mechanisms to escape from human immune responses. To resist phagocytic clearance, S. aureus expresses a polysaccharide capsule, which effectively masks the bacterial surface and surface-associated proteins, such as opsonins, from recognition by phagocytic cells. Additionally, secretion of the extracellular fibrinogen binding protein (Efb) potently blocks phagocytic uptake of the pathogen. Efb creates a fibrinogen shield surrounding the bacteria by simultaneously binding complement C3b and fibrinogen at the bacterial surface. By means of neutrophil phagocytosis assays with fluorescently labelled encapsulated serotype 5 (CP5) and serotype 8 (CP8) strains we compare the immune-modulating function of these shielding mechanisms. The data indicate that, in highly encapsulated S. aureus strains, the polysaccharide capsule is able to prevent phagocytic uptake at plasma concentrations <10 %, but loses its protective ability at higher concentrations of plasma. Interestingly, Efb shows a strong inhibitory effect on both capsule-negative and encapsulated strains at all tested plasma concentrations. Furthermore, the results suggest that both shielding mechanisms can exist simultaneously and collaborate to provide optimal protection against phagocytosis at a broad range of plasma concentrations. As opsonizing antibodies will be shielded from recognition by either mechanism, incorporating both capsular polysaccharides and Efb in future vaccines could be of great importance.

[Antibacterial actin of vinegar against food-borne pathogenic bacteria including Escherichia coli O157:H7 (Part 2). Effect of sodium chloride and temperature on bactericidal activity].

PubMed

Entani, E; Asai, M; Tsujihata, S; Tsukamoto, Y; Ohta, M

1997-05-01

Bactericidal effects of various kinds of AWASEZU (processed vinegar, 2.5% acidity) on food-borne pathogenic bacteria including Escherichia coli O157:H7 and other bacteria were examined. the order of bactericidal activities was NIHAIZU (3.5% NaCl was added) > SANBA-IZU (3.5% NaCl and 10% sucrose were added) > plain vinegar (spirit vinegar) > AMAZU (10% sucrose was added). This indicates that their activities were enhanced by the addition of sodium chloride and suppressed by the addition of sugar. On the other hand, when soy sauce was used instead of sodium chloride, the order of bactericidal activities was plain vinegar > AMAZU > NIHAIZU > SANBAIZU. This is mainly because their activities were suppressed by the increase in the pH value. The effect of sodium chloride (0.01-15%) and temperature (10-50 degrees C) on bactericidal activities against E. coli O157:H7 in spirit vinegar (0.5-2.5% acidity) was further examined. When vinegar was used in combination with sodium chloride, predominant synergism on the bactericidal activity was observed. Their activities were markedly enhanced by the addition of sodium chloride in proportion to the concentration. In addition to this, at higher temperatures spirit vinegar killed bacteria much more rapidly. It should be noted that the bactericidal activity of spirit vinegar was extremely enhanced by the combined use of the addition of sodium chloride and the rise of temperature. For example, in 2.5% acidity vinegar, the time required for 3 log decrease in viable cell numbers at 20 degrees C was shortened to 1/140-fold by the addition of 5% sodium chloride, shortened to 1/51-fold by the rise of the reaction temperature at 40 degrees C, and shortened to 1/830-fold; 0.89 minutes by both the addition of 5% sodium chloride and the rise of temperature at 40 degrees C. In order to propose the methods to prevent food poisoning by bacterial infection, bactericidal activities of vinegar solution containing sodium chloride on cooking tools and raw vegetables were examined. Vinegar solution (1-2% acidity, 3-7% NaCl) produced more than 3 log decrease in viable cell numbers of E. coli O157:H7 on the surface of cutting board, and cabbage and cucumber at 20-50 degrees C. These results suggested that the treatment with vinegar solution containing sodium chloride may be one of the useful methods to prevent food poisoning.

Selenium-mediated protection in reversing the sensitivity of bacterium to the bactericidal antibiotics.

PubMed

Li, Zhonglei; Tan, Jun; Shao, Lei; Dong, Xiaojing; Ye, Richard D; Chen, Daijie

2017-05-01

Inducing production of damaging reactive oxygen species (ROS) is an important criterion to distinguish the bactericidal antibiotics from bacteriostatic antibiotics. Selenoenzymes were generally recognized to be a powerful antioxidant capable of scavenging free radicals, protecting the cells from the harmful effects of ROS. Therefore, the present study was carried out to investigate the selenium (Se)-mediated protection in reversing antibiotic sensitivity and the role of selenoenzymes in alleviating the negative effects of oxidative stress. The cellular antioxidant activity of Se-enriched bacteria was analyzed, as well as intracellular ROS production and elimination when Se-enriched bacteria in the presence of various antibiotics. Compared to complete inhibition of the parental strain by bactericidal antibiotics, it only exhibited slight and reversible inhibition of Se-enriched Escherichia coli ATCC25922 and Staphylococcus aureus ATCC25923 at the same conditions, which indicated that intracellular selenium provided substantial protection against antibiotics. ROS generation caused by bactericidal antibiotics was confirmed by fluorescence spectrophotometry using 2', 7'-dichloro- uorescein diacetate (DCFH-DA) as substrate. The time course experiments of pretreatment with selenium showed significant decrease of ROS level at 2h. In summary, the present study provides experimental evidence supporting selenoenzymes has good scavenging effect to ROS and can protect bacteria from oxidative stress injury induced by bactericidal antibiotics. Copyright © 2017 Elsevier GmbH. All rights reserved.

PHAGOCYTIN: A BACTERICIDAL SUBSTANCE FROM POLYMORPHONUCLEAR LEUCOCYTES

PubMed Central

Hirsch, James G.

1956-01-01

A technique has been developed for collecting large numbers of polymorphonuclear leucocytes from peritoneal exudates in rabbits. These cells are obtained essentially free from other cell types and from debris. When microphages so procured are disrupted by physical methods and extracted with aqueous salt solutions, the soluble fraction manifests striking bactericidal activity, especially on Gram-negative enteric bacilli. The susceptible microorganisms are not lysed. This bactericidal substance, which has been called phagocytin, appears to be limited in distribution mainly to the polymorphonuclear leucocyte. No phagocytin is present in extracts of rabbit heart, kidney, or skeletal muscle, and rabbit liver and spleen contain much less than do packed leucocytes. Extracts of human and of guinea pig microphages show less bactericidal activity than rabbit cell preparations. Similar extracts of rat and mouse polymorphonuclear leucocytes contain no demonstrable phagocytin. As indicated by its behavior on dialysis, on exposure to proteolytic enzymes, and on salt fractionation, phagocytin appears to be a protein with general properties characteristic of a globulin. It is clearly different from lysozyme and from properdin. Although phagocytin is reasonably stable at temperatures of 65°C. and lower for several hours, solutions of it gradually lose bactericidal activity on standing for prolonged periods at 4°C. This instability, and also the ease with which phagocytin is inactivated, presumably by adsorption, on exposure to a variety of materials, have thus far rendered fruitless efforts to isolate it. PMID:13319580

Toxicity of twenty-two plant essential oils against pathogenic bacteria of vegetables and mushrooms.

PubMed

Todorović, Biljana; Potočnik, Ivana; Rekanović, Emil; Stepanović, Miloš; Kostić, Miroslav; Ristić, Mihajlo; Milijašević-Marčić, Svetlana

2016-12-01

ASBTRACT Toxicity of twenty-two essential oils to three bacterial pathogens in different horticultural systems: Xanthomonas campestris pv. phaseoli (causing blight of bean), Clavibacter michiganensis subsp. michiganensis (bacterial wilt and canker of tomato), and Pseudomonas tolaasii (causal agent of bacterial brown blotch on cultivated mushrooms) was tested. Control of bacterial diseases is very difficult due to antibiotic resistance and ineffectiveness of chemical products, to that essential oils offer a promising alternative. Minimal inhibitory and bactericidal concentrations are determined by applying a single drop of oil onto the inner side of each plate cover in macrodilution assays. Among all tested substances, the strongest and broadest activity was shown by the oils of wintergreen (Gaultheria procumbens), oregano (Origanum vulgare), and lemongrass (Cymbopogon flexuosus. Carvacrol (64.0-75.8%) was the dominant component of oregano oils, while geranial (40.7%) and neral (26.7%) were the major constituents of lemongrass oil. Xanthomonas campestris pv. phaseoli was the most sensitive to plant essential oils, being susceptible to 19 oils, while 11 oils were bactericidal to the pathogen. Sixteen oils inhibited the growth of Clavibacter michiganensis subsp. michiganensis and seven oils showed bactericidal effects to the pathogen. The least sensitive species was Pseudomonas tolaasii as five oils inhibited bacterial growth and two oils were bactericidal. Wintergreen, oregano, and lemongrass oils should be formulated as potential biochemical bactericides against different horticultural pathogens.

Understanding of gas phase deposition of reactive magnetron sputtered TiO2 thin films and its correlation with bactericidal efficiency

NASA Astrophysics Data System (ADS)

Panda, A. B.; Mahapatra, S. K.; Barhai, P. K.; Das, A. K.; Banerjee, I.

2012-10-01

Nanostructured TiO2 thin films were deposited using RF reactive magnetron sputtering at different O2 flow rates (20, 30, 50 and 60 sccm) and constant RF power of 200 W. In situ investigation of the nucleation and growth of the films was made by Optical Emission Spectroscopy (OES). The nano amorphous nature as revealed from X-ray diffraction (XRD) of the as deposited films and abundance of the Ti3+ surface oxidation states and surface hydroxyl group (OH-) in the films deposited at 50 sccm as determined from X-ray photo electron spectroscopy (XPS) was explained on the basis of emission spectra studies. The increase in band gap and decrease in particle size with O2 flow rate was observed from transmission spectra of UV-vis spectroscopy. Photoinduced hydrophilicity has been studied using Optical Contact Angle (OCA) measurement. The post irradiated films showed improved hydrophilicity. The bactericidal efficiency of these films was investigated taking Escherichia coli as model bacteria. The films deposited at 50 sccm shows better bactericidal activity as revealed from the optical density (OD) measurement. The qualitative analysis of the bactericidal efficiency was depicted from Scanning Electron Microscope images. A correlation between bactericidal efficiency and the deposited film has been established and explained on the basis of nucleation growth, band gap and hydrophilicity of the films.

Comparison and Correlation of Neisseria meningitidis Serogroup B Immunologic Assay Results and Human Antibody Responses following Three Doses of the Norwegian Meningococcal Outer Membrane Vesicle Vaccine MenBvac

PubMed Central

Findlow, Jamie; Taylor, Stephen; Aase, Audun; Horton, Rachel; Heyderman, Robert; Southern, Jo; Andrews, Nick; Barchha, Rita; Harrison, Ewan; Lowe, Ann; Boxer, Emma; Heaton, Charlotte; Balmer, Paul; Kaczmarski, Ed; Oster, Philipp; Gorringe, Andrew; Borrow, Ray; Miller, Elizabeth

2006-01-01

The prediction of efficacy of Neisseria meningitidis serogroup B (MenB) vaccines is currently hindered due to the lack of an appropriate correlate of protection. For outer membrane vesicle (OMV) vaccines, immunogenicity has primarily been determined by the serum bactericidal antibody (SBA) assay and OMV enzyme-linked immunosorbent assay (ELISA). However, the opsonophagocytic assay (OPA), surface labeling assay, whole blood assay (WBA), and salivary antibody ELISA have been developed although correlation with protection is presently undetermined. Therefore, the aim of the study was to investigate further the usefulness of, and relationships between, MenB immunologic assays. A phase II trial of the OMV vaccine, MenBvac, with proven efficacy was initiated to compare immunologic assays incorporating the vaccine and six heterologous strains. Correlations were achieved between the SBA assay, OMV ELISA, and OPA using human polymorphonuclear leukocytes and human complement but not between an OPA using HL60 phagocytic cells and baby rabbit complement. Correlations between the surface labeling assay, the SBA assay, and the OMV ELISA were promising, although target strain dependent. Correlations between the salivary antibody ELISA and other assays were poor. Correlations to the WBA were prevented since many samples had results greater than the range of the assay. The study confirmed the immunogenicity and benefit of a third dose of MenBvac against the homologous vaccine strain using a variety of immunologic assays. These results emphasize the need for standardized methodologies that would allow a more robust comparison of assays between laboratories and promote their further evaluation as correlates of protection against MenB disease. PMID:16861642

Comparative analysis of innate immune responses to Streptococcus phocae strains in Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss).

PubMed

Salazar, Soraya; Oliver, Cristian; Yáñez, Alejandro J; Avendaño-Herrera, Ruben

2016-04-01

Streptococcus phocae subsp. salmonis is a Gram-positive bacterium that causes mortality only in Atlantic salmon (Salmo salar) farmed in Chile, even when this species is co-cultured with rainbow trout (Oncorhynchus mykiss). This susceptibility could be determined by innate immune response components and their responses to bacterial infection. This fish pathogen shares subspecies status with Streptococcus phocae subsp. phocae isolated from seals. The present study compared innate immune system mechanisms in Atlantic salmon and rainbow trout when challenged with different S. phocae, including two isolates from Atlantic salmon (LM-08-Sp and LM-13-Sp) and two from seal (ATCC 51973(T) and P23). Streptococcus phocae growth was evaluated in the mucus and serum of both species, with rainbow trout samples evidencing inhibitory effects. Lysozyme activity supported this observation, with significantly higher (p < 0.01) expression in rainbow trout serum and mucus as compared to Atlantic salmon. No differences were found in phagocytic capacity between fish species when stimulated with ATCC 51973(T) and P23. Against all S. phocae strains, rainbow trout and Atlantic salmon showed up to two-fold increased bactericidal activity, and rainbow trout demonstrated up to three-fold greater reactive oxygen species production in macrophages. In conclusion, the non-specific humoral and cellular barriers of Atlantic salmon were immunologically insufficient against S. phocae subsp. salmonis, thereby facilitating streptococcosis. Moreover, the more robust response of rainbow trout to S. phocae could not be attributed to any specific component of the innate immune system, but was rather the consequence of a combined response by the evaluated components. Copyright © 2016 Elsevier Ltd. All rights reserved.

Neutralization of bactericidal activity related to antimicrobial carry-over in broiler carcass rinse samples

USDA-ARS?s Scientific Manuscript database

Chemical antimicrobial interventions used as poultry processing aids may have potential for carry-over into whole poultry carcass buffered peptone water (BPW) rinses collected for the recovery of viable Salmonella. Such carry-over may lead to false negative indications due to continuing bactericidal...

Antagonistic effects of lipids against the bactericidal activity of thymol-beta-D-glucopyranoside

USDA-ARS?s Scientific Manuscript database

The gut of food-producing animals is a reservoir for zoonotic pathogens. Thymol is bactericidal against Salmonella, E. coli, and Campylobacter, but its rapid absorption from the proximal gut reveals a need for protective technologies to deliver effective concentrations to the lower gut where the pa...

Suppressive effect of delta 9-tetrahydrocannabinol in vitro on phagocytosis by murine macrophages.

PubMed

Friedman, M; Cepero, M L; Klein, T; Friedman, H

1986-06-01

Incubation of normal mouse peritoneal cells consisting of over 90% phagocytizing macrophages with delta 9-tetrahydrocannabinol (THC) resulted in a inhibition of phagocytic function. The THC in a dose-related manner suppressed the percentage of macrophages per culture which ingested yeast and the average number of yeast particles ingested by the phagocytizing macrophages. The vehicle used to suspend the THC in vitro, i.e., DMSO, had no detectable effect on macrophage function. Suppression of phagocytosis with no effects on viability or cell number occurred with doses of 10 micrograms or less THC per milliliter culture medium. Measurable suppression also occurred after 24- to 48-hr treatment of the macrophages with the THC. This compound had little if any detectable effect on phagocytosis when added directly to the cultures shortly before testing for phagocytosis. Further studies concerning the effects of THC on macrophage function appear warranted.

[Regulation of cellular-mediated immunity by Chenopodi boni henrici herba polysaccharides in hens].

PubMed

Hanganu, Daniela; Dorhoi, Anca; Pintea, Adela; Olah, Neli; Sevastre, B

2010-01-01

The immunomodulatory effect of polysaccharides from Chenopodium bonus-henricus herba was tested on adult hens. Blood samples were harvested aseptically by punction of brachial vein; ability of circulating phagocytes was assessed by the carbon particles phagocytosis test in vitro; while reactivity of peripheral lymphocytes was evaluated by lymphocytes transformation assay in vitro. Polysaharides were dissolved in saline solution and filtered throughout Millipore. Phagocytic indexes (at 15 and 39 minutes) are variable according to polysaharides concentration; phagocytosis increased at 15 minutes for 40 microg/mL and 60 microg/mL, while for 30 minutes the phagocytic index decreased. In lymphocytes transformation assay, Chenopodium bonus-henricus polysaharides, alone, shown no stimulatory effect, and together to the classic mitogen, their influence was variable, but not statistical significant results were seen. Polysaccharides have inconstant effect on phagocytosis, and mainly inhibitory role on lymphocytes proliferation.

Brazilian Propolis: A Natural Product That Improved the Fungicidal Activity by Blood Phagocytes

PubMed Central

Possamai, Muryllo Mendes; Honorio-França, Adenilda Cristina; Reinaque, Ana Paula Barcelos; França, Eduardo Luzia; Souto, Paula Cristina de Souza

2013-01-01

Natural product incorporation into microcarriers increases the bioavailability of these compounds, consequently improving their therapeutic properties. Natural products, particularly those from bees such as propolis, are widely used in popular medicine. Propolis is a powerful treatment for several diseases. In this context, the present study evaluated the effect of propolis Scaptotrigona sp. and its fractions, alone or adsorbed to polyethylene glycol (PEG) microspheres, on the activity of human phagocytes against Candida albicans. The results show that propolis exerts a stimulatory effect on these cells to assist in combating the fungus, especially as the crude extract is compared with the fractions. However, when incorporated into microspheres, these properties were significantly potentiated. These results suggest that propolis adsorbed onto PEG microspheres has immunostimulatory effects on phagocytes in human blood. Therefore, propolis may potentially be an additional natural product that can be used for a variety of therapies. PMID:23509737

A rapid microtiter plate serum bactericidal assay method for determining serum complement-mediated killing of Mannheimia haemolytica.

PubMed

Ayalew, Sahlu; Confer, Anthony W; Shrestha, Binu; Payton, Mark E

2012-05-01

In this study, we describe a rapid microtiter serum bactericidal assay (RMSBA) that can be used to measure the functionality of immune sera. It quantifies bactericidal activity of immune sera in the presence of complement against a homologous bacterium, M. haemolytica in this case. There is high correlation between data from RMSBA and standard complement-mediated bacterial killing assay (r=0.756; p<0.0001). The RMSBA activity of sera can be generated in less than 5 h instead of overnight incubation. RMSBA costs substantially less in terms of time, labor, and resources and is highly reproducible. Copyright © 2012 Elsevier B.V. All rights reserved.

Validation of CoaBC as a Bactericidal Target in the Coenzyme A Pathway of Mycobacterium tuberculosis.

PubMed

Evans, Joanna C; Trujillo, Carolina; Wang, Zhe; Eoh, Hyungjin; Ehrt, Sabine; Schnappinger, Dirk; Boshoff, Helena I M; Rhee, Kyu Y; Barry, Clifton E; Mizrahi, Valerie

2016-12-09

Mycobacterium tuberculosis relies on its own ability to biosynthesize coenzyme A to meet the needs of the myriad enzymatic reactions that depend on this cofactor for activity. As such, the essential pantothenate and coenzyme A biosynthesis pathways have attracted attention as targets for tuberculosis drug development. To identify the optimal step for coenzyme A pathway disruption in M. tuberculosis, we constructed and characterized a panel of conditional knockdown mutants in coenzyme A pathway genes. Here, we report that silencing of coaBC was bactericidal in vitro, whereas silencing of panB, panC, or coaE was bacteriostatic over the same time course. Silencing of coaBC was likewise bactericidal in vivo, whether initiated at infection or during either the acute or chronic stages of infection, confirming that CoaBC is required for M. tuberculosis to grow and persist in mice and arguing against significant CoaBC bypass via transport and assimilation of host-derived pantetheine in this animal model. These results provide convincing genetic validation of CoaBC as a new bactericidal drug target.

Nonspecific bactericidal activity of the lactoperoxidases-thiocyanate-hydrogen peroxide system of milk against Escherichia coli and some gram-negative pathogens.

PubMed Central

Reiter, B; Marshall, V M; BjörckL; Rosén, C G

1976-01-01

Two strains of Escherichia coli and one strain each of Salmonella typhimurium and Pseudomonas aeruginosa were killed by the bactericidal activity of the lactoperoxidase-thiocyanate-hydrogen peroxide system in milk and in a synthetic medium. H2O2 was supplied exogenously by glucose oxidase, and glucose was produced at a level which was itself noninhibitory. Two phases were distinguished: the first phase was dependent on the oxidation of SCN(-) by lactoperoxidase and H2O2, which was reversed by reducing agent, and the second phase was dependent on the presence of accumulated H2O2, which was reversed by catalase. The latter enzyme could also reverse the first phase, but only when present in excessive and unphysiological levels. The bactericidal activity was greatest at pH 5 and below, and it depended on the SCN(-)concentration and on the number of organisms. Since raw or heated milk neutralizes the acid barrier against infection in the stomach, the bactericidal system discussed may contribute to the prevention of enteric infections in neonates. PMID:5374

Grouper (Epinephelus coioides) IL-34/MCSF2 and MCSFR1/MCSFR2 were involved in mononuclear phagocytes activation against Cryptocaryon irritans infection.

PubMed

Mo, Ze-Quan; Li, Yan-Wei; Zhou, Ling; Li, An-Xing; Luo, Xiao-Chun; Dan, Xue-Ming

2015-03-01

MCSF and its well-known receptor MCSFR had been well studied in humans, regulating the differentiation, proliferation, and survival of the mononuclear phagocyte system. IL-34, which is an alternative ligand of MCSF receptor, was recently identified as a novel cytokine and functionally overlaps with MCSF. However, the functional study of these receptors and their ligands in fish are largely unknown. In the present study, the cDNA of two potential grouper MCSFR ligands have been cloned, EcIL-34 (657 bp) and EcMCSF2 (804 bp), as well as an additional copy of grouper MCSFR, EcMCSFR2 (3141 bp). Sequence analysis showed that these three molecules had higher identities with other fish counterparts compared to mammals and their conserved structures and important functional residues were also analyzed. Tissue distribution analysis showed that EcIL-34 is dominant in brain, gill and spleen compared to EcMCSF2, which is dominant in head kidney, trunk kidney, skin, heart and muscle. EcMCSFR1 was dominant in the most tissues except head kidney and liver compared to EcMCSFR2. The different tissue distribution patterns of these two grouper MCSF receptors and their two ligands indicate the different mononuclear phagocyte differentiation and activation modes in different tissues. In Cryptocaryon irritans infected grouper, EcIL-34 and EcMCSFR2 were the most strongly up-regulated ligand and receptor in the infected sites, gill and skin. Their up-regulation confirmed the proliferation and activation of phagocytes in C. irritans infected sites, which would improve the antigen presentation and elicit the host local specific immune response. In C. irritans infected grouper head kidney, both ligands EcIL-34 and EcMCSF2 (especially EcMCSF2) were up-regulated, but both receptors EcMCSFR1 and EcMCSFR2 were down-regulated, which indicated that the phagocytes differentiation and proliferation may have occurred in this hemopoietic organ, and after that they migrated to the infected cites. The down-regulation of EcIL-34 and EcMCSF2 and no significant change of EcMCSFR1 and EcMCSFR2 in most time point of grouper spleen showed it was less involved in phagocytes response to C. irritans infection. Copyright © 2014 Elsevier Ltd. All rights reserved.

It takes two to tango: Phagocyte and lymphocyte numbers in a small mammalian hibernator.

PubMed

Havenstein, Nadine; Langer, Franz; Stefanski, Volker; Fietz, Joanna

2016-02-01

Immunity is energetically costly and competes for resources with other physiological body functions, which may result in trade-offs that impair fitness during demanding situations. Endocrine mediators, particularly stress hormones, play a central role in these relationships and directly impact leukocyte differentials. To determine the effects of external stressors, energetic restraints and competing physiological functions on immune parameters and their relevance for fitness, we investigated leukocyte profiles during the active season of a small obligate hibernator, the edible dormouse (Glis glis), in five different study sites in south-western Germany. The highly synchronized yearly cycle of this species and the close adaptation of its life history to the irregular abundance of food resources provide a natural experiment to elucidate mechanisms underlying variations in fitness parameters. In contrast to previous studies on hibernators, that showed an immediate recovery of all leukocyte subtypes upon emergence, our study revealed that hibernation results in depleted phagocyte (neutrophils and monocytes) stores that recovered only slowly. As the phenomenon of low phagocyte counts was even more pronounced at the beginning of a low food year and primarily immature neutrophils were present in the blood upon emergence, preparatory mechanisms seem to determine the regeneration of phagocytes before hibernation is terminated. Surprisingly, the recovery of phagocytes thereafter took several weeks, presumably due to energetic restrictions. This impaired first line of defense coincides with lowest survival probabilities during the annual cycle of our study species. Reduced survival could furthermore be linked to drastic increases in the P/L ratio (phagocytes/lymphocytes), an indicator of physiological stress, during reproduction. On the other hand, moderate augmentations in the P/L ratio occurred during periods of low food availability and were associated with increased survival, but reproductive failure. In this case, the stress response probably represents an adaptive reaction that contributes to survival by activating energy resources. In contrast to our expectation, we could not detect an amplification of stress through high population densities. Summarized, results of our study clearly reveal that the leukocyte picture of active edible dormice responds sensitively to physiological conditions associated with hibernation, reproductive activity and food availability and can be linked to fitness parameters such as survival. Thus edible dormice represent an excellent model organism to investigate regulatory mechanisms of the immune system under natural conditions. Copyright © 2015 Elsevier Inc. All rights reserved.

[Influence of corynebacteria metabolites on antagonistic activity of H2O2 producing lactobacilli].

PubMed

Bukharin, O V; Sgibnev, A V

2012-01-01

Study combined influence of Corynebacterium genus bacteria metabolites and H2O2 producing lactobacilli on survival rate of Staphylococcus aureus, Escherichia coli and Lactobacillus acidophilus. The ability to inhibit catalase of the test strains used and to reduce bactericidal effect of hydroxyl radical were determined in corynebacteria. H2O2 containing metabolites were obtained by cultivating lactobacilli in mineral medium, the amount of H2O2 was determined by oxidation of TMB by peroxidase. Bactericidal effect of lactobacilli metabolites for test strains treated by corynebacteria metabolites was evaluated by seeding results. Results. Inhibitio by corynebacteria metabolites of S. aureus catalase activity by 30-40% and E. coli catalase activ ity by 40-70% was shown. A reduction of bactericidal effect of hydroxyl radicals by corynebacteria metabolites by 30-35% for S. aureus, 38-42% for E. coli and 70-73% for L. acidophilus was noted. The enchantment of bactericidal effect of lactobacilli after treatment of the test strain by corynebacteria metabolites against S. aureus and E. coli manifested by reduction of the numbe of viable cells by 2-3 lg CFU. For L. acidophilus the bactericidal effect oflactobacilli metabolite in the same conditions reduced, and that led to the increase ofviability by 2-4 lg PFU. A conclusion on the possibility of regulation by associative bacteria the manifestations of antagonistic activity of H2O2 producing dominant microorganisms is made based on the data obtained.

Antimicrobial activity of wild mushroom extracts against clinical isolates resistant to different antibiotics.

PubMed

Alves, M J; Ferreira, I C F R; Martins, A; Pintado, M

2012-08-01

This work aimed to screen the antimicrobial activity of aqueous methanolic extracts of 13 mushroom species, collected in Bragança, against several clinical isolates obtained in Hospital Center of Trás-os-Montes and Alto Douro, Portugal. Microdilution method was used to determine the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). MIC results showed that Russula delica and Fistulina hepatica extracts inhibited the growth of gram-negative (Escherichia coli, Morganella morganni and Pasteurella multocida) and gram-positive (Staphylococcus aureus, MRSA, Enterococcus faecalis, Listeria monocytogenes, Streptococcus agalactiae and Streptococcus pyogenes) bacteria. A bactericide effect of both extracts was observed in Past. multocida, Strep. agalactiae and Strep. pyogenes with MBC of 20, 10 and 5 mg ml⁻¹, respectively. Lepista nuda extract exhibited a bactericide effect upon Past. multocida at 5 mg ml⁻¹ and inhibited Proteus mirabilis at 20 mg ml⁻¹. Ramaria botrytis extract showed activity against Enterococcus faecalis and L. monocytogenes, being bactericide for Past. multocida, Strep. agalactiae (MBCs 20 mg ml⁻¹) and Strep. pyogenes (MBC 10 mg ml⁻¹). Leucopaxillus giganteus extract inhibited the growth of E. coli and Pr. mirabilis, being bactericide for Past. multocida, Strep. pyogenes and Strep. agalactiae. Fistulina hepatica, R. botrytis and R. delica are the most promising species as antimicrobial agents. Mushroom extracts could be an alternative as antimicrobials against pathogenic micro-organisms resistant to conventional treatments. © 2012The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

Urease from Helicobacter pylori is inactivated by sulforaphane and other isothiocyanates

PubMed Central

Fahey, Jed W.; Stephenson, Katherine K.; Wade, Kristina L.; Talalay, Paul

2013-01-01

Infections by Helicobacter pylori are very common, causing gastroduodenal inflammation including peptic ulcers, and increasing the risk of gastric neoplasia. The isothiocyanate (ITC) sulforaphane [SF; 1-isothiocyanato-4-(methylsulfinyl)butane] derived from edible crucifers such as broccoli is potently bactericidal against Helicobacter, including antibiotic-resistant strains, suggesting a possible dietary therapy. Gastric H. pylori infections express high urease activity which generates ammonia, neutralizes gastric acidity, and promotes inflammation. The finding that SF inhibits (inactivates) urease (jack bean and Helicobacter) raised the issue of whether these properties might be functionally related. The rates of inactivation of urease activity depend on enzyme and SF concentrations and show first order kinetics. Treatment with SF results in time-dependent increases in the ultraviolet absorption of partially purified Helicobacter urease in the 280–340 nm region. This provides direct spectroscopic evidence for the formation of dithiocarbamates between the ITC group of SF and cysteine thiols of urease. The potencies of inactivation of Helicobacter urease by isothiocyanates structurally related to SF were surprisingly variable. Natural isothiocyanates closely related to SF, previously shown to be bactericidal (berteroin, hirsutin, phenethyl isothiocyanate, alyssin, and erucin), did not inactivate urease activity. Furthermore, SF is bactericidal against both urease positive and negative H. pylori strains. In contrast, some isothiocyanates such as benzoyl-ITC, are very potent urease inactivators, but are not bactericidal. The bactericidal effects of SF and other ITC against Helicobacter are therefore not obligatorily linked to urease inactivation, but may reduce the inflammatory component of Helicobacter infections. PMID:23583386

Mechanisms of action of escapin, a bactericidal agent in the ink secretion of the sea hare Aplysia californica: rapid and long-lasting DNA condensation and involvement of the OxyR-regulated oxidative stress pathway.

PubMed

Ko, Ko-Chun; Tai, Phang C; Derby, Charles D

2012-04-01

The marine snail Aplysia californica produces escapin, an L-amino acid oxidase, in its defensive ink. Escapin uses L-lysine to produce diverse products called escapin intermediate products of L-lysine (EIP-K), including α-amino-ε-caproic acid, Δ¹-piperidine-2-carboxylic acid, and Δ²-piperidine-2-carboxylic acid. EIP-K and H₂O₂ together, but neither alone, is a powerful bactericide. Here, we report bactericidal mechanisms of escapin products on Escherichia coli. We show that EIP-K and H₂O₂ together cause rapid and long-lasting DNA condensation: 2-min treatment causes significant DNA condensation and killing, and 10-min treatment causes maximal effect, lasting at least 70 h. We isolated two mutants resistant to EIP-K plus H₂O₂, both having a single missense mutation in the oxidation regulatory gene, oxyR. A complementation assay showed that the mutated gene, oxyR(A233V), renders resistance to EIP-K plus H₂O₂, and a gene dosage effect leads to reduction of resistance for strains carrying wild-type oxyR. Temperature stress with EIP-K does not produce the bactericidal effect, suggesting the effect is due to a specific response to oxidative stress. The null mutant for any single DNA-binding protein--Dps, H-NS, Hup, Him, or MukB--was not resistant to EIP-K plus H₂O₂, suggesting that no single DNA-binding protein is necessary to mediate this bactericidal effect, but allowing for the possibility that EIP-K plus H₂O₂ could function through a combination of DNA-binding proteins. The bactericidal effect of EIP-K plus H₂O₂ was eliminated by the ferrous ion chelator 1,10-phenanthroline, and it was reduced by the hydroxyl radical scavenger thiourea, suggesting hydroxyl radicals mediate the effects of EIP-K plus H₂O₂.

Bactericidal activity and post-antibiotic effect of ozenoxacin against Propionibacterium acnes.

PubMed

Kanayama, Shoji; Okamoto, Kazuaki; Ikeda, Fumiaki; Ishii, Ritsuko; Matsumoto, Tatsumi; Hayashi, Naoki; Gotoh, Naomasa

2017-06-01

Ozenoxacin, a novel non-fluorinated topical quinolone, is used for the treatment of acne vulgaris in Japan. We investigated bactericidal activity and post-antibiotic effect (PAE) of ozenoxacin against Propionibacterium acnes, a major causative bacterium of acne vulgaris. The minimum inhibitory concentrations (MICs) of ozenoxacin against 3 levofloxacin-susceptible strains (MIC of levofloxacin; ≤4 μg/mL) and 3 levofloxacin-resistant strains (MIC of levofloxacin; ≥8 μg/mL) ranged from 0.03 to 0.06 μg/mL and from 0.25 to 0.5 μg/mL, respectively. These MICs of ozenoxacin were almost the same or lower than nadifloxacin and clindamycin. The minimum bactericidal concentrations (MBCs) of ozenoxacin against the levofloxacin-susceptible and -resistant strains were from 0.06 to 8 μg/mL and from 0.5 to 4 μg/mL, respectively. These MBCs were lower than those of nadifloxacin and clindamycin. In time-kill assay, ozenoxacin at 1/4, 1 and 4 times the respective MIC against both levofloxacin-susceptible and -resistant strains showed a concentration-dependent bactericidal activity. Ozenoxacin at 4 times the MICs against the levofloxacin-susceptible strains showed more potent and more rapid onset of bactericidal activity compared to nadifloxacin and clindamycin at 4 times the respective MICs. The PAEs of ozenoxacin at 4 times the MICs against the levofloxacin-susceptible strains were from 3.3 to 17.1 h, which were almost the same or longer than nadifloxacin and clindamycin. In contrast, the PAEs were hardly induced by any antimicrobial agents against the levofloxacin-resistant strains. The present findings suggest that ozenoxacin has a potent bactericidal activity against both levofloxacin-susceptible and -resistant P. acnes, and a long-lasting PAE against levofloxacin-susceptible P. acnes. Copyright © 2017 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Characterization of myosin light chain in shrimp hemocytic phagocytosis.

PubMed

Han, Fang; Wang, Zhiyong; Wang, Xiaoqing

2010-11-01

Myosin light chain, a well-known cytoskeleton gene, regulates multiple processes that are involved in material transport, muscle shrink and cell division. However, its function in phagocytosis against invading pathogens in crustacean remains unknown. In this investigation, a myosin light chain gene was obtained from Marsupenaeus japonicus shrimp. The full-length cDNA of this gene was of 766 bp and an open reading frame (ORF) of 462 bp encoding a polypeptide of 153 amino acids. The myosin light chain protein was expressed in Escherichia coli and purified. Subsequently the specific antibody was raised using the purified GST fusion protein. As revealed by immuno-electron microscopy, the myosin light chain protein was only expressed in the dark bands of muscle. In the present study, the myosin light chain gene was up-regulated in the WSSV-resistant shrimp as revealed by real-time PCR and western blot. And the phagocytic percentage and phagocytic index using FITC-labeled Vibrio parahemolyticus were remarkably increased in the WSSV-resistant shrimp, suggesting that the myosin light chain protein was essential in hemocytic phagocytosis. On the other hand, RNAi assays indicated that the phagocytic percentage and phagocytic index were significantly decreased when the myosin light chain gene was silenced by sequence-specific siRNA. These findings suggested that myosin light chain protein was involved in the regulation of hemocytic phagocytosis of shrimp. Copyright 2010 Elsevier Ltd. All rights reserved.

Bruton's Tyrosine Kinase (BTK) and Vav1 Contribute to Dectin1-Dependent Phagocytosis of Candida albicans in Macrophages

PubMed Central

Strijbis, Karin; Tafesse, Fikadu G.; Fairn, Gregory D.; Witte, Martin D.; Dougan, Stephanie K.; Watson, Nicki; Spooner, Eric; Esteban, Alexandre; Vyas, Valmik K.; Fink, Gerald R.; Grinstein, Sergio; Ploegh, Hidde L.

2013-01-01

Phagocytosis of the opportunistic fungal pathogen Candida albicans by cells of the innate immune system is vital to prevent infection. Dectin-1 is the major phagocytic receptor involved in anti-fungal immunity. We identify two new interacting proteins of Dectin-1 in macrophages, Bruton's Tyrosine Kinase (BTK) and Vav1. BTK and Vav1 are recruited to phagocytic cups containing C. albicans yeasts or hyphae but are absent from mature phagosomes. BTK and Vav1 localize to cuff regions surrounding the hyphae, while Dectin-1 lines the full length of the phagosome. BTK and Vav1 colocalize with the lipid PI(3,4,5)P3 and F-actin at the phagocytic cup, but not with diacylglycerol (DAG) which marks more mature phagosomal membranes. Using a selective BTK inhibitor, we show that BTK contributes to DAG synthesis at the phagocytic cup and the subsequent recruitment of PKCε. BTK- or Vav1-deficient peritoneal macrophages display a defect in both zymosan and C. albicans phagocytosis. Bone marrow-derived macrophages that lack BTK or Vav1 show reduced uptake of C. albicans, comparable to Dectin1-deficient cells. BTK- or Vav1-deficient mice are more susceptible to systemic C. albicans infection than wild type mice. This work identifies an important role for BTK and Vav1 in immune responses against C. albicans. PMID:23825946

Bruton's Tyrosine Kinase (BTK) and Vav1 contribute to Dectin1-dependent phagocytosis of Candida albicans in macrophages.

PubMed

Strijbis, Karin; Tafesse, Fikadu G; Fairn, Gregory D; Witte, Martin D; Dougan, Stephanie K; Watson, Nicki; Spooner, Eric; Esteban, Alexandre; Vyas, Valmik K; Fink, Gerald R; Grinstein, Sergio; Ploegh, Hidde L

2013-01-01

Phagocytosis of the opportunistic fungal pathogen Candida albicans by cells of the innate immune system is vital to prevent infection. Dectin-1 is the major phagocytic receptor involved in anti-fungal immunity. We identify two new interacting proteins of Dectin-1 in macrophages, Bruton's Tyrosine Kinase (BTK) and Vav1. BTK and Vav1 are recruited to phagocytic cups containing C. albicans yeasts or hyphae but are absent from mature phagosomes. BTK and Vav1 localize to cuff regions surrounding the hyphae, while Dectin-1 lines the full length of the phagosome. BTK and Vav1 colocalize with the lipid PI(3,4,5)P3 and F-actin at the phagocytic cup, but not with diacylglycerol (DAG) which marks more mature phagosomal membranes. Using a selective BTK inhibitor, we show that BTK contributes to DAG synthesis at the phagocytic cup and the subsequent recruitment of PKCε. BTK- or Vav1-deficient peritoneal macrophages display a defect in both zymosan and C. albicans phagocytosis. Bone marrow-derived macrophages that lack BTK or Vav1 show reduced uptake of C. albicans, comparable to Dectin1-deficient cells. BTK- or Vav1-deficient mice are more susceptible to systemic C. albicans infection than wild type mice. This work identifies an important role for BTK and Vav1 in immune responses against C. albicans.

Fibrin(ogen) mediates acute inflammatory responses to biomaterials

PubMed Central

1993-01-01

Although "biocompatible" polymeric elastomers are generally nontoxic, nonimmunogenic, and chemically inert, implants made of these materials may trigger acute and chronic inflammatory responses. Early interactions between implants and inflammatory cells are probably mediated by a layer of host proteins on the material surface. To evaluate the importance of this protein layer, we studied acute inflammatory responses of mice to samples of polyester terephthalate film (PET) that were implanted intraperitoneally for short periods. Material preincubated with albumin is "passivated," accumulating very few adherent neutrophils or macrophages, whereas uncoated or plasma- coated PET attracts large numbers of phagocytes. Neither IgG adsorption nor surface complement activation is necessary for this acute inflammation; phagocyte accumulation on uncoated implants is normal in hypogammaglobulinemic mice and in severely hypocomplementemic mice. Rather, spontaneous adsorption of fibrinogen appears to be critical: (a) PET coated with serum or hypofibrinogenemic plasma attracts as few phagocytes as does albumin-coated material; (b) in contrast, PET preincubated with serum or hypofibrinogenemic plasma containing physiologic amounts of fibrinogen elicits "normal" phagocyte recruitment; (c) most importantly, hypofibrinogenemic mice do not mount an inflammatory response to implanted PET unless the material is coated with fibrinogen or the animals are injected with fibrinogen before implantation. Thus, spontaneous adsorption of fibrinogen appears to initiate the acute inflammatory response to an implanted polymer, suggesting an interesting nexus between two major iatrogenic effects of biomaterials: clotting and inflammation. PMID:8245787

Melatonin signaling affects the timing in the daily rhythm of phagocytic activity by the retinal pigment epithelium.

PubMed

Laurent, Virgine; Sengupta, Anamika; Sánchez-Bretaño, Aída; Hicks, David; Tosini, Gianluca

2017-12-01

Earlier studies in Xenopus have indicated a role for melatonin in the regulation of retinal disk shedding, but the role of melatonin in the regulation of daily rhythm in mammalian disk shedding and phagocytosis is still unclear. We recently produced a series of transgenic mice lacking melatonin receptor type 1 (MT 1 ) or type 2 (MT 2 ) in a melatonin-proficient background and have shown that removal of MT 1 and MT 2 receptors induces significant effects on daily and circadian regulation of the electroretinogram as well as on the viability of photoreceptor cells during aging. In this study we investigated the daily rhythm of phagocytic activity by the retinal pigment epithelium in MT 1 and MT 2 knock-out mice. Our data indicate that in MT 1 and MT 2 knock-out mice the peak of phagocytosis is advanced by 3 h with respect to wild-type mice and occurred in dark rather than after the onset of light, albeit the mean phagocytic activity over the 24-h period did not change among the three genotypes. Nevertheless, this small change in the profile of daily phagocytic rhythms may produce a significant effect on retinal health since MT 1 and MT 2 knock-out mice showed a significant increase in lipofuscin accumulation in the retinal pigment epithelium. Copyright © 2017 Elsevier Ltd. All rights reserved.

Insight into phagocytosis of mature sexual (gametocyte) stages of Plasmodium falciparum using a human monocyte cell line.

PubMed

Bansal, Geetha P; Weinstein, Corey S; Kumar, Nirbhay

2016-05-01

During natural infection malaria parasites are injected into the bloodstream of a human host by the bite of an infected female Anopheles mosquito. Both asexual and mature sexual stages of Plasmodium circulate in the blood. Asexual forms are responsible for clinical malaria while sexual stages are responsible for continued transmission via the mosquitoes. Immune responses generated against various life cycle stages of the parasite have important roles in resistance to malaria and in reducing malaria transmission. Phagocytosis of free merozoites and erythrocytic asexual stages has been well studied, but very little is known about similar phagocytic clearance of mature sexual stages, which are critical for transmission. We evaluated phagocytic uptake of mature sexual (gametocyte) stage parasites by a human monocyte cell line in the absence of immune sera. We found that intact mature stages do not undergo phagocytosis, unless they are either killed or freed from erythrocytes. In view of this observation, we propose that the inability of mature gametocytes to be phagocytized may actually result in malaria transmission advantage. On the other hand, mature gametocytes that are not transmitted to mosquitoes during infection will eventually die and undergo phagocytosis, initiating immune responses that may have transmission blocking potential. A better understanding of early phagocytic clearance and immune responses to gametocytes may identify additional targets for transmission blocking strategies. Copyright © 2016 Elsevier B.V. All rights reserved.

Lysosomal degradation of the carboxydextran shell of coated superparamagnetic iron oxide nanoparticles and the fate of professional phagocytes.

PubMed

Lunov, Oleg; Syrovets, Tatiana; Röcker, Carlheinz; Tron, Kyrylo; Nienhaus, G Ulrich; Rasche, Volker; Mailänder, Volker; Landfester, Katharina; Simmet, Thomas

2010-12-01

Contrast agents based on dextran-coated superparamagnetic iron oxide nanoparticles (SPIO) are internalized by professional phagocytes such as hepatic Kupffer cells, yet their role in phagocyte biology remains largely unknown. Here we investigated the effects of the SPIO ferucarbotran on murine Kupffer cells and human macrophages. Intravenous injection of ferucarbotran into mice led to rapid accumulation of the particles in phagocytes and to long-lasting increased iron deposition in liver and kidneys. Macrophages incorporate ferucarbotran in lysosomal vesicles containing α-glucosidase, which is capable of degrading the carboxydextran shell of the ferucarbotran particles. Intravenous injection of ferucarbotran into mice followed by incorporation of the nanoparticles into Kupffer cells triggered apoptosis and the subsequent depletion of Kupffer cells. In macrophages, the proinflammatory cytokine TNF-α increased the apoptosis rate, the reactive oxygen species production and the activation of c-Jun N-terminal kinase elicited by ferucarbotran, which might be mediated by the induction of cytoplasmic phospholipase A2 by TNF-α. Notably, the nanoparticle-induced apoptosis of murine Kupffer cells could be prevented by treatment of the mice with the radical scavenger edaravone. Thus, nanosized carboxydextran-coated SPIO-based contrast agents are retained for extended time periods by liver macrophages, where they elicit delayed cell death, which can be antagonized by a therapeutic radical scavenger. Copyright © 2010 Elsevier Ltd. All rights reserved.

Selective Biological Responses of Phagocytes and Lungs to Purified Histones.

PubMed

Fattahi, Fatemeh; Grailer, Jamison J; Lu, Hope; Dick, Rachel S; Parlett, Michella; Zetoune, Firas S; Nuñez, Gabriel; Ward, Peter A

2017-01-01

Histones invoke strong proinflammatory responses in many different organs and cells. We assessed biological responses to purified or recombinant histones, using human and murine phagocytes and mouse lungs. H1 had the strongest ability in vitro to induce cell swelling independent of requirements for toll-like receptors (TLRs) 2 or 4. These responses were also associated with lactate dehydrogenase release. H3 and H2B were the strongest inducers of [Ca2+]i elevations in phagocytes. Cytokine and chemokine release from mouse and human phagocytes was predominately a function of H2A and H2B. Double TLR2 and TLR4 knockout (KO) mice had dramatically reduced cytokine release induced in macrophages exposed to individual histones. In contrast, macrophages from single TLR-KO mice showed few inhibitory effects on cytokine production. Using the NLRP3 inflammasome protocol, release of mature IL-1β was predominantly a feature of H1. Acute lung injury following the airway delivery of histones suggested that H1, H2A, and H2B were linked to alveolar leak of albumin and the buildup of polymorphonuclear neutrophils as well as the release of chemokines and cytokines into bronchoalveolar fluids. These results demonstrate distinct biological roles for individual histones in the context of inflammation biology and the requirement of both TLR2 and TLR4. © 2017 S. Karger AG, Basel.

Polysialic acid blocks mononuclear phagocyte reactivity, inhibits complement activation, and protects from vascular damage in the retina.

PubMed

Karlstetter, Marcus; Kopatz, Jens; Aslanidis, Alexander; Shahraz, Anahita; Caramoy, Albert; Linnartz-Gerlach, Bettina; Lin, Yuchen; Lückoff, Anika; Fauser, Sascha; Düker, Katharina; Claude, Janine; Wang, Yiner; Ackermann, Johannes; Schmidt, Tobias; Hornung, Veit; Skerka, Christine; Langmann, Thomas; Neumann, Harald

2017-02-01

Age-related macular degeneration (AMD) is a major cause of blindness in the elderly population. Its pathophysiology is linked to reactive oxygen species (ROS) and activation of the complement system. Sialic acid polymers prevent ROS production of human mononuclear phagocytes via the inhibitory sialic acid-binding immunoglobulin-like lectin-11 (SIGLEC11) receptor. Here, we show that low-dose intravitreal injection of low molecular weight polysialic acid with average degree of polymerization 20 (polySia avDP20) in humanized transgenic mice expressing SIGLEC11 on mononuclear phagocytes reduced their reactivity and vascular leakage induced by laser coagulation. Furthermore, polySia avDP20 prevented deposition of the membrane attack complex in both SIGLEC11 transgenic and wild-type animals. In vitro, polySia avDP20 showed two independent, but synergistic effects on the innate immune system. First, polySia avDP20 prevented tumor necrosis factor-α, vascular endothelial growth factor A, and superoxide production by SIGLEC11-positive phagocytes. Second, polySia avDP20 directly interfered with complement activation. Our data provide evidence that polySia avDP20 ameliorates laser-induced damage in the retina and thus is a promising candidate to prevent AMD-related inflammation and angiogenesis. © 2016 The Authors. Published under the terms of the CC BY 4.0 license.

Evaluation of bactericidal effect of three antiseptics on bacteria isolated from wounds.

PubMed

Kumara, D U A; Fernando, S S N; Kottahachchi, J; Dissanayake, D M B T; Athukorala, G I D D A D; Chandrasiri, N S; Damayanthi, K W N; Hemarathne, M H S L; Pathirana, A A

2015-01-01

Antiseptics are widely used in wound management to prevent or treat wound infections due to their proven wound healing properties regardless of their cytotoxicity. The objective of this study was to determine the bactericidal effects of three antiseptics on pathogens known to cause wound infections. The study was carried out at a tertiary care hospital and a university microbiology laboratory in Sri Lanka in 2013. The three acids (acetic acid, ascorbic acid and boric acid) in increasing concentration (0.5%, 0.75% and 1%) were tested against bacterial suspensions equivalent to 0.5 McFarland standard. The Bacteria isolates used were isolated from wound and standard strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. There were 33 (68.8%) Coliforms, 10 (20.8%) Pseudomonas species, and 5 (10.4%) strains of Staphylococcus aureus. Acetic acid at concentration of 0.5% inhibited growth of 37 (77%) and 42 (87.5%) of tested isolates when exposed for 30 and 60 minutes, respectively. However 100% inhibition was achieved at four hours. At a concentration of 0.75%, 40 (83.3%) and 44 (91.7%) were inhibited when exposed for 30 and 60 minutes, respectively, with 100% inhibition at 4 hours. At concentration of 1%, 46 (95.8%) inhibition was seen at 30 minutes and 100% inhibition at 60 minutes. Ascorbic acid, at 0.5% and 0.75 % concentrations, inhibited growth of 45(93.7%) and 47(97.9%) of isolates respectively when exposed for 30 minutes. At these two concentrations, 100% inhibition was achieved when exposed for one hour. At 1% concentration, 100% inhibition was achieved at 30 minutes. Boric acid did not show bactericidal effect at concentrations of 0.5%, 0.75 % and 1%. Pseudomonas species were inhibited at 30 minutes by 0.5% acetic acid. Bactericidal effect against all the standard strains was seen with three acids at each concentration tested from 30 minutes onwards Ascorbic acid was bactericidal for all organisms tested within the shortest exposure time at the lowest concentration compared to other two acids. Despite promising bactericidal effects, further studies warrant, as ongoing debates on toxicity of acids on tissue epithelialisation. Application of antiseptics for a shorter duration could overcome this problem without losing bactericidal activity. The authors have no conflict of interest and no funding was received for this study.

Bactericidal activity of self-assembled palmitic and stearic fatty acid crystals on highly ordered pyrolytic graphite.

PubMed

Ivanova, Elena P; Nguyen, Song Ha; Guo, Yachong; Baulin, Vladimir A; Webb, Hayden K; Truong, Vi Khanh; Wandiyanto, Jason V; Garvey, Christopher J; Mahon, Peter J; Mainwaring, David E; Crawford, Russell J

2017-09-01

The wings of insects such as cicadas and dragonflies have been found to possess nanostructure arrays that are assembled from fatty acids. These arrays can physically interact with the bacterial cell membranes, leading to the death of the cell. Such mechanobactericidal surfaces are of significant interest, as they can kill bacteria without the need for antibacterial chemicals. Here, we report on the bactericidal effect of two of the main lipid components of the insect wing epicuticle, palmitic (C16) and stearic (C18) fatty acids. Films of these fatty acids were re-crystallised on the surface of highly ordered pyrolytic graphite. It appeared that the presence of two additional CH 2 groups in the alkyl chain resulted in the formation of different surface structures. Scanning electron microscopy and atomic force microscopy showed that the palmitic acid microcrystallites were more asymmetric than those of the stearic acid, where the palmitic acid microcrystallites were observed to be an angular abutment in the scanning electron micrographs. The principal differences between the two types of long-chain saturated fatty acid crystallites were the larger density of peaks in the upper contact plane of the palmitic acid crystallites, as well as their greater proportion of asymmetrical shapes, in comparison to that of the stearic acid film. These two parameters might contribute to higher bactericidal activity on surfaces derived from palmitic acid. Both the palmitic and stearic acid crystallite surfaces displayed activity against Gram-negative, rod-shaped Pseudomonas aeruginosa and Gram-positive, spherical Staphylococcus aureus cells. These microcrystallite interfaces might be a useful tool in the fabrication of effective bactericidal nanocoatings. Nanostructured cicada and dragonfly wing surfaces have been discovered to be able physically kill bacterial cells. Here, we report on the successful fabrication of bactericidal three-dimensional structures of two main lipid components of the epicuticle of insect wings, palmitic (C16) and stearic (C18) acids. After crystallisation onto highly ordered pyrolytic graphite, both the palmitic and stearic acid films displayed bactericidal activity against both Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus cells. The simplicity of the production of these microcrystallite interfaces suggests that a fabrication technique, based on solution deposition, could be an effective technique for the application of bactericidal nanocoatings. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Do physico-chemical properties of silver nanoparticles decide their interaction with biological media and bactericidal action? A review.

PubMed

Pareek, Vikram; Gupta, Rinki; Panwar, Jitendra

2018-09-01

The unprecedented increase in antibiotic resistance in this era has resuscitated the attention of scientific community to exploit silver and its various species as antimicrobial agents. Plenty of studies have been done to measure the antimicrobial potential of silver species (cationic silver, metallic Ag 0 or silver nanoparticles, silver oxide particulates etc.) and indicated that membrane damage, oxidative stress, protein dysfunction and DNA damage to be the possible cause of injury to the microbial cell. However, the precise molecular mechanism of their mode of action has remained unclear, which makes an obstacle towards the generation of potential antibacterial agent against various pathogenic and multidrug resistant (MDR) bacteria. In order to endeavor this issue, one should first have the complete understanding about the resistance mechanisms present in bacteria that can be a therapeutic target for the silver-based drug formulations. Apart from this, in-depth understanding of the interactions of various silver species (with the biological media) is a probable deciding factor for the synthesis of silver-based drug formulations because the particular form and physico-chemical properties of silver can ultimately decide their antimicrobial action. In context to above mentioned serious concerns, the present article aims to discuss the mechanisms behind the confrontation of bacteria against various drugs and the effect of physico-chemical properties of silver species on their bactericidal action as well as critically evaluates the available reports on bacterial transcriptomic and proteomic profiles upon the exposure of various silver species. Further, this review state the mechanism of action that needs to be followed for the complete understanding of toxic potential of silver nanoparticles, which will open a possibility to synthesize new silver nanoparticle based antimicrobial systems with desired properties to ensure their safe use, exposure over extended period and fate in human body and environment. Copyright © 2018 Elsevier B.V. All rights reserved.

Pranic meditation affects phagocyte functions and hormonal levels of recent practitioners.

PubMed

Fernandes, César A; Nóbrega, Yanna K M; Tosta, C Eduardo

2012-08-01

Despite the recognized importance of phagocytes in the maintenance and recovery of health, the influence of meditation on their functions is not properly established. This investigation aimed at evaluating the influence of pranic meditation on the functions of phagocytes, and on the levels of hormones that influence them. A pre-post design was adopted. The investigation was carried out at a university research laboratory. Twenty-nine (29) healthy individuals of both sexes, 24-67 years old (median 45), with no previous experience in meditation, received 3-hour-duration weekly training on pranic meditation during 10 weeks and agreed to engage in daily home practice for 20 minutes. Pranic meditation is a novel method of meditation, based on the Vedic tradition, which uses techniques of breathing and visualization for quieting the mind, and for capturing and intentionally directing prana ("vital energy") wherever necessary. For assessing phagocytosis, the production of hydrogen peroxide and nitric oxide by monocytes, and the concentrations of corticotrophin and cortisol, blood was collected at the beginning (week 1), at the middle (week 5), and by the end (week 10) of the practice period. At the same intervals, melatonin concentrations were evaluated in the saliva. Those who meditated for more than 980 minutes showed increased phagocytosis, their monocytes produced higher concentrations of hydrogen peroxide, and their plasma levels of corticotrophin were reduced. The production of nitric oxide by monocytes, and the levels of cortisol and melatonin were not modified by meditation. This is the first study to show that a short program of pranic meditation practice was able to upregulate the function and metabolism of phagocytes, in parallel with the reduction of the plasma levels of corticotrophin. The results of this study point to a possible causal effect between these events, and indicate that pranic meditation could be useful for stimulating the function and metabolism of phagocytes.

New Insights into the Immunobiology of Mononuclear Phagocytic Cells and Their Relevance to the Pathogenesis of Cardiovascular Diseases

PubMed Central

Sanmarco, Liliana Maria; Eberhardt, Natalia; Ponce, Nicolás Eric; Cano, Roxana Carolina; Bonacci, Gustavo; Aoki, Maria Pilar

2018-01-01

Macrophages are the primary immune cells that reside within the myocardium, suggesting that these mononuclear phagocytes are essential in the orchestration of cardiac immunity and homeostasis. Independent of the nature of the injury, the heart triggers leukocyte activation and recruitment. However, inflammation is harmful to this vital terminally differentiated organ with extremely poor regenerative capacity. As such, cardiac tissue has evolved particular strategies to increase the stress tolerance and minimize the impact of inflammation. In this sense, growing evidences show that mononuclear phagocytic cells are particularly dynamic during cardiac inflammation or infection and would actively participate in tissue repair and functional recovery. They respond to soluble mediators such as metabolites or cytokines, which play central roles in the timing of the intrinsic cardiac stress response. During myocardial infarction two distinct phases of monocyte influx have been identified. Upon infarction, the heart modulates its chemokine expression profile that sequentially and actively recruits inflammatory monocytes, first, and healing monocytes, later. In the same way, a sudden switch from inflammatory macrophages (with microbicidal effectors) toward anti-inflammatory macrophages occurs within the myocardium very shortly after infection with Trypanosoma cruzi, the causal agent of Chagas cardiomyopathy. While in sterile injury, healing response is necessary to stop tissue damage; during an intracellular infection, the anti-inflammatory milieu in infected hearts would promote microbial persistence. The balance of mononuclear phagocytic cells seems to be also dynamic in atherosclerosis influencing plaque initiation and fate. This review summarizes the participation of mononuclear phagocyte system in cardiovascular diseases, keeping in mind that the immune system evolved to promote the reestablishment of tissue homeostasis following infection/injury, and that the effects of different mediators could modulate the magnitude and quality of the immune response. The knowledge of the effects triggered by diverse mediators would serve to identify new therapeutic targets in different cardiovascular pathologies. PMID:29375564

New Insights into the Immunobiology of Mononuclear Phagocytic Cells and Their Relevance to the Pathogenesis of Cardiovascular Diseases.

PubMed

Sanmarco, Liliana Maria; Eberhardt, Natalia; Ponce, Nicolás Eric; Cano, Roxana Carolina; Bonacci, Gustavo; Aoki, Maria Pilar

2017-01-01

Macrophages are the primary immune cells that reside within the myocardium, suggesting that these mononuclear phagocytes are essential in the orchestration of cardiac immunity and homeostasis. Independent of the nature of the injury, the heart triggers leukocyte activation and recruitment. However, inflammation is harmful to this vital terminally differentiated organ with extremely poor regenerative capacity. As such, cardiac tissue has evolved particular strategies to increase the stress tolerance and minimize the impact of inflammation. In this sense, growing evidences show that mononuclear phagocytic cells are particularly dynamic during cardiac inflammation or infection and would actively participate in tissue repair and functional recovery. They respond to soluble mediators such as metabolites or cytokines, which play central roles in the timing of the intrinsic cardiac stress response. During myocardial infarction two distinct phases of monocyte influx have been identified. Upon infarction, the heart modulates its chemokine expression profile that sequentially and actively recruits inflammatory monocytes, first, and healing monocytes, later. In the same way, a sudden switch from inflammatory macrophages (with microbicidal effectors) toward anti-inflammatory macrophages occurs within the myocardium very shortly after infection with Trypanosoma cruzi , the causal agent of Chagas cardiomyopathy. While in sterile injury, healing response is necessary to stop tissue damage; during an intracellular infection, the anti-inflammatory milieu in infected hearts would promote microbial persistence. The balance of mononuclear phagocytic cells seems to be also dynamic in atherosclerosis influencing plaque initiation and fate. This review summarizes the participation of mononuclear phagocyte system in cardiovascular diseases, keeping in mind that the immune system evolved to promote the reestablishment of tissue homeostasis following infection/injury, and that the effects of different mediators could modulate the magnitude and quality of the immune response. The knowledge of the effects triggered by diverse mediators would serve to identify new therapeutic targets in different cardiovascular pathologies.

Mycobacterium avium biofilm attenuates mononuclear phagocyte function by triggering hyperstimulation and apoptosis during early infection.

PubMed

Rose, Sasha J; Bermudez, Luiz E

2014-01-01

Mycobacterium avium subsp. hominissuis is an opportunistic human pathogen that has been shown to form biofilm in vitro and in vivo. Biofilm formation in vivo appears to be associated with infections in the respiratory tract of the host. The reasoning behind how M. avium subsp. hominissuis biofilm is allowed to establish and persist without being cleared by the innate immune system is currently unknown. To identify the mechanism responsible for this, we developed an in vitro model using THP-1 human mononuclear phagocytes cocultured with established M. avium subsp. hominissuis biofilm and surveyed various aspects of the interaction, including phagocyte stimulation and response, bacterial killing, and apoptosis. M. avium subsp. hominissuis biofilm triggered robust tumor necrosis factor alpha (TNF-α) release from THP-1 cells as well as superoxide and nitric oxide production. Surprisingly, the hyperstimulated phagocytes did not effectively eliminate the cells of the biofilm, even when prestimulated with gamma interferon (IFN-γ) or TNF-α or cocultured with natural killer cells (which have been shown to induce anti-M. avium subsp. hominissuis activity when added to THP-1 cells infected with planktonic M. avium subsp. hominissuis). Time-lapse microscopy and the TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling) assay determined that contact with the M. avium subsp. hominissuis biofilm led to early, widespread onset of apoptosis, which is not seen until much later in planktonic M. avium subsp. hominissuis infection. Blocking TNF-α or TNF-R1 during interaction with the biofilm significantly reduced THP-1 apoptosis but did not lead to elimination of M. avium subsp. hominissuis. Our data collectively indicate that M. avium subsp. hominissuis biofilm induces TNF-α-driven hyperstimulation and apoptosis of surveilling phagocytes, which prevents clearance of the biofilm by cells of the innate immune system and allows the biofilm-associated infection to persist.

Preventing Ototoxic Synergy of Prior Noise Trauma during Aminoglycoside Therapy

DTIC Science & Technology

2017-06-01

with aminoglycoside antibiotics that have broad-spectrum bactericidal activity for treating or preventing life-threatening infections. However...with aminoglycoside antibiotics that have broad- spectrum bactericidal activity for treating or preventing life-threatening infections. However...aminoglycoside uptake. What was accomplished under these goals? 1) Major activities Due to lab relocation, the project was interrupted in 2015, and

EFFECT OF INORGANIC CATIONS ON BACTERICIDAL ACTIVITY OF ANIONIC SURFACTANTS

PubMed Central

Voss, J. G.

1963-01-01

Voss, J. G. (Procter & Gamble Co., Cincinnati, Ohio). Effect of inorganic cations on bactericidal activity of anionic surfactants. J. Bacteriol. 86:207–211. 1963.—The bactericidal effectiveness of two alkyl benzene sulfonates and of three other types of anionic surfactants against Staphylococcus aureus is increased in the presence of low concentrations of divalent cations, especially alkaline earths and metals of group IIB of the periodic table. The cations may act by decreasing the negative charge at the cell surface and increasing adsorption of the surfactant anions, leading to damage to the cytoplasmic membrane and death of the cell. Increased adsorption of surfactant is also found with Escherichia coli, but does not lead to death of the cell. PMID:14058942

Synthesis and characterization of bactericidal silver nanoparticles using cultural filtrate of simulated microgravity grown Klebsiella pneumoniae.

PubMed

Kalpana, Duraisamy; Lee, Yang Soo

2013-03-05

Silver nanoparticles were synthesized by biological method using cultural filtrate of Klebsiella pneumoniae cultured under simulated microgravity and silver nitrate solution as precursor. The nanoparticles exhibited typical plasmon absorption maximum of silver nanoparticles between 405 and 407 nm. Spherical silver nanoparticles were found to have size between 15 and 37 nm by TEM analysis. XRD pattern corresponding to planes (111), (200), (220) (311) revealed the crystalline nature of the biosynthesized silver nanoparticles. FTIR spectrum proposed stabilization of silver nanoparticles by the protein molecules present in the cultural filtrate. The silver nanoparticles exhibited high bactericidal activity against Salmonella enterica, Escherichia coli and moderate bactericidal activity against Streptococcus pyogenes. Copyright © 2012 Elsevier Inc. All rights reserved.

Different virulence of influenza A virus strains and susceptibility to pneumococcal otitis media in chinchillas.

PubMed Central

Giebink, G S; Wright, P F

1983-01-01

We have previously shown that chinchillas infected with a multiply passaged laboratory strain of influenza A/NWS/33 (H1N1) develop negative middle-ear pressure; polymorphonuclear leukocyte oxidative, bactericidal, and chemotactic dysfunction; and increased susceptibility to pneumococcal otitis media. Because influenza A virus strains show different virulence in humans, three such strains were compared in the chinchilla model. Negative middle-ear pressure and tympanic membrane inflammation developed significantly more often in chinchillas infected with wild-type H3N2 virus than with either wild-type H1N1 virus or an attenuated, cold-adapted H3N2 vaccine strain, CR29. Marked depression in polymorphonuclear leukocyte chemiluminescent activity also developed significantly more often in H3N2 infected animals than in H1N1- or CR29-infected animals. Intranasal challenge of influenza virus-infected animals with type 7 Streptococcus pneumoniae resulted in a significantly greater occurrence of pneumococcal otitis media in H3N2-infected animals than in H1N1-, CR29-, or non-influenza-infected control animals. Clearance of pneumococci from nasal washings of animals infected with wild-type H3N2 was significantly delayed in comparison with the other groups. Thus, the previously demonstrated increased susceptibility to otitis media among children infected with H3N2 influenza virus may relate to the capacity of this strain to induce negative middle-ear pressure, polymorphonuclear leukocyte dysfunction, and alteration in the mucosal clearance of pneumococci. PMID:6885170

Urease from Helicobacter pylori is inactivated by sulforaphane and other isothiocyanates.

PubMed

Fahey, Jed W; Stephenson, Katherine K; Wade, Kristina L; Talalay, Paul

2013-05-24

Infections by Helicobacter pylori are very common, causing gastroduodenal inflammation including peptic ulcers, and increasing the risk of gastric neoplasia. The isothiocyanate (ITC) sulforaphane [SF; 1-isothiocyanato-4-(methylsulfinyl)butane] derived from edible crucifers such as broccoli is potently bactericidal against Helicobacter, including antibiotic-resistant strains, suggesting a possible dietary therapy. Gastric H. pylori infections express high urease activity which generates ammonia, neutralizes gastric acidity, and promotes inflammation. The finding that SF inhibits (inactivates) urease (jack bean and Helicobacter) raised the issue of whether these properties might be functionally related. The rates of inactivation of urease activity depend on enzyme and SF concentrations and show first order kinetics. Treatment with SF results in time-dependent increases in the ultraviolet absorption of partially purified Helicobacter urease in the 260-320 nm region. This provides direct spectroscopic evidence for the formation of dithiocarbamates between the ITC group of SF and cysteine thiols of urease. The potencies of inactivation of Helicobacter urease by isothiocyanates structurally related to SF were surprisingly variable. Natural isothiocyanates closely related to SF, previously shown to be bactericidal (berteroin, hirsutin, phenethyl isothiocyanate, alyssin, and erucin), did not inactivate urease activity. Furthermore, SF is bactericidal against both urease positive and negative H. pylori strains. In contrast, some isothiocyanates such as benzoyl-ITC, are very potent urease inactivators, but are not bactericidal. The bactericidal effects of SF and other ITC against Helicobacter are therefore not obligatorily linked to urease inactivation, but may reduce the inflammatory component of Helicobacter infections. Copyright © 2013 Elsevier Inc. All rights reserved.

Diesel Exhaust Particles Contribute to Endothelia Apoptosis via Autophagy Pathway.

PubMed

Wang, Jhih-Syuan; Tseng, Chia-Yi; Chao, Ming-Wei

2017-03-01

Epidemiological studies suggest that an increase of PM2.5 diesel exhaust particles (DEP) in ambient air corresponds to increased myocardial infarctions and atherosclerosis. When exposed to DEP, endothelial cells exhibit increases in oxidative stress and apoptosis, but the role of autophagy in this DEP-induced cell death remains unclear. Here, we suggest that acute DEP exposure produces intracellular reactive oxygen species (ROS) leading to induction of DEP internalization, endothelial dysfunction, and pro-inflammation in an in vitro human umbilical vein endothelial cells (HUVEC) model. This study found that increases in intracellular oxidative stress and cellular internalization of DEP occurred within 2 h of exposure to DEP. After 2 h of DEP exposure, Mdm2 expression was increased, which triggered cellular autophagy after 4 h of DEP exposure and suppressed cellular senescence. Unfortunately, phagocytized DEP could not be eliminated by cellular autophagy, which led to a continuous buildup of ROS, an increased release of cytokines, and an increased expression of anchoring molecules. After 12 h of DEP exposure, HUVEC reduced Mdm2 expression leading to increased p53 expression, which triggered apoptosis and ultimately resulted in endothelial dysfunction. On the other hand, when cells lacked the ability to induce autophagy, DEP was unable to induce cell senescence and most of the cells survived with only a small percentage of the cells undergoing necrosis. The results presented in this study clearly demonstrate the role cellular autophagy plays in DEP-induced atherosclerosis. © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

The Phagocytic Function of Macrophage-Enforcing Innate Immunity and Tissue Homeostasis.

PubMed

Hirayama, Daisuke; Iida, Tomoya; Nakase, Hiroshi

2017-12-29

Macrophages are effector cells of the innate immune system that phagocytose bacteria and secrete both pro-inflammatory and antimicrobial mediators. In addition, macrophages play an important role in eliminating diseased and damaged cells through their programmed cell death. Generally, macrophages ingest and degrade dead cells, debris, tumor cells, and foreign materials. They promote homeostasis by responding to internal and external changes within the body, not only as phagocytes, but also through trophic, regulatory, and repair functions. Recent studies demonstrated that macrophages differentiate from hematopoietic stem cell-derived monocytes and embryonic yolk sac macrophages. The latter mainly give rise to tissue macrophages. Macrophages exist in all vertebrate tissues and have dual functions in host protection and tissue injury, which are maintained at a fine balance. Tissue macrophages have heterogeneous phenotypes in different tissue environments. In this review, we focused on the phagocytic function of macrophage-enforcing innate immunity and tissue homeostasis for a better understanding of the role of tissue macrophages in several pathological conditions.

NADPH oxidases: novel therapeutic targets for neurodegenerative diseases.

PubMed

Gao, Hui-Ming; Zhou, Hui; Hong, Jau-Shyong

2012-06-01

Oxidative stress is a key pathologic factor in neurodegenerative diseases such as Alzheimer and Parkinson diseases (AD, PD). The failure of free-radical-scavenging antioxidants in clinical trials pinpoints an urgent need to identify and to block major sources of oxidative stress in neurodegenerative diseases. As a major superoxide-producing enzyme complex in activated phagocytes, phagocyte NADPH oxidase (PHOX) is essential for host defense. However, recent preclinical evidence has underscored a pivotal role of overactivated PHOX in chronic neuroinflammation and progressive neurodegeneration. Deficiency in PHOX subunits mitigates neuronal damage induced by diverse insults/stresses relevant to neurodegenerative diseases. More importantly, suppression of PHOX activity correlates with reduced neuronal impairment in models of neurodegenerative diseases. The discovery of PHOX and non-phagocyte NADPH oxidases in astroglia and neurons further reinforces the crucial role of NADPH oxidases in oxidative stress-mediated chronic neurodegeneration. Thus, proper modulation of NADPH oxidase activity might hold therapeutic potential for currently incurable neurodegenerative diseases. Published by Elsevier Ltd.

Differentiation and Glucocorticoid Regulated Apopto-Phagocytic Gene Expression Patterns in Human Macrophages. Role of Mertk in Enhanced Phagocytosis

PubMed Central

Zahuczky, Gábor; Kristóf, Endre; Majai, Gyöngyike; Fésüs, László

2011-01-01

The daily clearance of physiologically dying cells is performed safely mainly by cells in the mononuclear phagocyte system. They can recognize and engulf dying cells utilizing several cooperative mechanisms. In our study we show that the expression of a broad range of apopto-phagocytic genes is strongly up-regulated during differentiation of human monocytes to macrophages with different donor variability. The glucocorticoid dexamethasone has a profound effect on this process by selectively up-regulating six genes and down-regulating several others. The key role of the up-regulated mer tyrosine kinase (Mertk) in dexamethasone induced enhancement of phagocytosis could be demonstrated in human monocyte derived macrophages by gene silencing as well as blocking antibodies, and also in a monocyte-macrophage like cell line. However, the additional role of other glucocorticoid induced elements must be also considered since the presence of autologous serum during phagocytosis could almost completely compensate for the blocked function of Mertk. PMID:21731712

Assessment of the cytotoxicity of a mineral trioxide aggregate-based sealer with respect to macrophage activity.

PubMed

Braga, Julia Mourão; Oliveira, Ricardo Reis; de Castro Martins, Renata; Vieira, Leda Quercia; Sobrinho, Antonio Paulino Ribeiro

2015-10-01

To assess the influence of co-culture with mineral trioxide aggregate (MTA) and MTA Fillapex (FLPX) on the viability, adherence, and phagocytosis activity of peritoneal macrophages from two mouse strains. Cellular viability, adherence, and phagocytosis of Saccharomyces boulardii were assayed in the presence of capillaries containing MTA and MTA Fillapex. The data were analyzed using parametric (Student's t) and non-parametric (Mann-Whitney) tests. FLPX was severely cytotoxic and decreased cell viability, adherence, and phagocytic activity of both macrophage subtypes. Cells that were treated with MTA Fillapex remained viable (>80%) for only 4 h after stimulation. Macrophages from C57BL/6 mice presented higher adherence and higher phagocytic activity compared with macrophages from BALB/c mice. Comparison of MTA and FLPX effects upon macrophages indicates that FLPX may impair macrophage activity and viability, while MTA seems to increase phagocytic activity. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Staphylococcus aureus leukocidin ED contributes to systemic infection by targeting neutrophils and promoting bacterial growth in vivo

PubMed Central

Alonzo, Francis; Benson, Meredith A.; Chen, John; Novick, Richard P.; Shopsin, Bo; Torres, Victor J.

2011-01-01

SUMMARY Bloodstream infection with Staphylococcus aureus is common and can be fatal. However, virulence factors that contribute to lethality in S. aureus bloodstream infection are poorly defined. We discovered that LukED, a commonly overlooked leukotoxin, is critical for S. aureus bloodstream infection in mice. We also determined that LukED promotes S. aureus replication in vivo by directly killing phagocytes recruited to sites of hematogenously-seeded tissue. Furthermore, we established that murine neutrophils are the primary target of LukED, as the greater virulence of wild type S. aureus compared to a lukED mutant was abrogated by depleting neutrophils. The in vivo toxicity of LukED toward murine phagocytes is unique among S. aureus leukotoxins, implying its crucial role in pathogenesis. Moreover, the tropism of LukED for murine phagocytes highlights the utility of murine models to study LukED pathobiology, including development and testing of strategies to inhibit toxin activity and control bacterial infection. PMID:22142035

Ontogeny of tick hemocytes: a comparative analysis of Ixodes ricinus and Ornithodoros moubata.

PubMed

Borovicková, Barbara; Hypsa, Václav

2005-01-01

Hemocytes of two tick species, Ixodes ricinus and Ornithodoros moubata, were investigated with the aim to determine their ultrastructural characteristics and developmental relationships. Only a limited number of ultrastructural features was shown to be unequivocally homological across all hemocyte types. The two species, representing distant groups of ticks, differ in the composition of their circular cell populations. In I. ricinus, three groups of distinct morphological types of hemocytes could be determined according to well-defined ultrastructural features: a typical non-phagocytic granular cell with electron-dense granula and homogeneous cytoplasm (Gr II), and two different types of phagocytic hemocytes, namely plasmatocytes with a low number of granula and phagocytic granolocytes, designated as Gr I. In contrast, an additional cell type resembling insect spherulocytes was determined in O. moubata. This cell type does not seem to be homologous to any I. ricinus hemocyte and may represent a cell type typical of soft ticks only. Possible ontogenetic lineages of the hemocytes of both tick-species were inferred.

Ultrastructures and classification of circulating hemocytes in 9 botryllid ascidians (chordata: ascidiacea).

PubMed

Hirose, Euichi; Shirae, Maki; Saito, Yasunori

2003-05-01

Ultrastructures of circulating hemocytes were studied in 9 botryllid ascidians. The hemocytes are classified into five types: hemoblasts, phagocytes, granulocytes, morula cells, and pigment cells. These five types are always found in the 9 species. They should represent the major hemocyte types of the circulating cells in the blood. Hemoblasts are small hemocytes having a high nucleus/cytoplasm ratio. There are few granular or vacuolar inclusions in the cytoplasm. Phagocytes have phagocytic activity and their shape is variable depending on the amount of engulfed materials. In granulocytes, shape and size of granules are different among the species. Morula cells are characterized by several vacuoles filled with electron dense materials. In pigment cells, the bulk of the cytoplasm is occupied by one or a few vacuoles containing pigment granules. We also described some other hemocyte types found in particular species. Furthermore, we encountered free oocytes circulating in the blood in two species, Botryllus primigenus and Botrylloides lentus.

Nanoblinker: Brownian Motion Powered Bio-Nanomachine for FRET Detection of Phagocytic Phase of Apoptosis

PubMed Central

Minchew, Candace L.; Didenko, Vladimir V.

2014-01-01

We describe a new type of bio-nanomachine which runs on thermal noise. The machine is solely powered by the random motion of water molecules in its environment and does not ever require re-fuelling. The construct, which is made of DNA and vaccinia virus topoisomerase protein, can detect DNA damage by employing fluorescence. It uses Brownian motion as a cyclic motor to continually separate and bring together two types of fluorescent hairpins participating in FRET. This bio-molecular oscillator is a fast and specific sensor of 5′OH double-strand DNA breaks present in phagocytic phase of apoptosis. The detection takes 30 s in solution and 3 min in cell suspensions. The phagocytic phase is critical for the effective execution of apoptosis as it ensures complete degradation of the dying cells’ DNA, preventing release of pathological, viral and tumor DNA and self-immunization. The construct can be used as a smart FRET probe in studies of cell death and phagocytosis. PMID:25268504

Phagocytic cell function in active brucellosis.

PubMed Central

Ocon, P; Reguera, J M; Morata, P; Juarez, C; Alonso, A; Colmenero, J D

1994-01-01

In this study, we analyzed phagocytic cell function in 51 patients with active brucellosis and its relationship with different clinical, serological, and evolutionary variables. A control group was made up of 30 blood donors of similar geographic extraction, age, and sex, with no previous history of brucellosis or known exposure ot the infection or specific antibodies. The investigations were carried out at the time of diagnosis, at the conclusion of treatment, and after 6 months of follow-up. Polymorphonuclear leukocyte adherence and nitroblue tetrazolium reduction in response to Brucella antigen were significantly increased in the patients at the time of diagnosis with respect to the control group. In contrast, chemotaxis in response to Brucella antigen and phagocytosis were significantly reduced in the patients with respect to the control group. The alterations in phagocytic cell function were greater in patients with bacteremia, with focal forms of the disease, or with a longer diagnostic delay. Most of these initial alterations tended to normalize with treatment, indicating their transient character. PMID:8112863

The multifaceted role of the renal mononuclear phagocyte system.

PubMed

Viehmann, Susanne F; Böhner, Alexander M C; Kurts, Christian; Brähler, Sebastian

2018-04-22

The kidney contains a large and complex network of mononuclear phagocytes, which includes dendritic cells (DCs) and macrophages (MØs). The distinction between these cell types is traditionally based on the expression of molecular markers and morphology. However, several classification systems are used in parallel to identify DCs and MØs, leading to considerable uncertainty about their identity and functional roles. The discovery that a substantial proportion of macrophages in tissues like the kidney are embryonically derived further complicates the situation. Recent studies have used newly identified transcription factors such as ZBTB46 and lineage tracing techniques for classifying mononuclear phagocytes. These approaches have shed new light on the functional specialization of these cells in health and disease, uncovered an influence of the renal microenvironment and revealed considerable cellular plasticity, especially in inflammatory situations. In this review, the current knowledge about the developmental origins and versatile functional roles of DCs and MØs in kidney homeostasis and disease is discussed. Copyright © 2018 Elsevier Inc. All rights reserved.

Divergence of macrophage phagocytic and antimicrobial programs in leprosy.

PubMed

Montoya, Dennis; Cruz, Daniel; Teles, Rosane M B; Lee, Delphine J; Ochoa, Maria Teresa; Krutzik, Stephan R; Chun, Rene; Schenk, Mirjam; Zhang, Xiaoran; Ferguson, Benjamin G; Burdick, Anne E; Sarno, Euzenir N; Rea, Thomas H; Hewison, Martin; Adams, John S; Cheng, Genhong; Modlin, Robert L

2009-10-22

Effective innate immunity against many microbial pathogens requires macrophage programs that upregulate phagocytosis and direct antimicrobial pathways, two functions generally assumed to be coordinately regulated. We investigated the regulation of these key functions in human blood-derived macrophages. Interleukin-10 (IL-10) induced the phagocytic pathway, including the C-type lectin CD209 and scavenger receptors, resulting in phagocytosis of mycobacteria and oxidized low-density lipoprotein. IL-15 induced the vitamin D-dependent antimicrobial pathway and CD209, yet the cells were less phagocytic. The differential regulation of macrophage functional programs was confirmed by analysis of leprosy lesions: the macrophage phagocytosis pathway was prominent in the clinically progressive, multibacillary form of the disease, whereas the vitamin D-dependent antimicrobial pathway predominated in the self-limited form and in patients undergoing reversal reactions from the multibacillary to the self-limited form. These data indicate that macrophage programs for phagocytosis and antimicrobial responses are distinct and differentially regulated in innate immunity to bacterial infections.

Eros is a novel transmembrane protein that controls the phagocyte respiratory burst and is essential for innate immunity

PubMed Central

Thomas, David C.; Clare, Simon; Sowerby, John M.; Juss, Jatinder K.; Goulding, David A.; van der Weyden, Louise; Prakash, Ananth; Harcourt, Katherine; Mukhopadhyay, Subhankar; Antrobus, Robin; Bateman, Alex

2017-01-01

The phagocyte respiratory burst is crucial for innate immunity. The transfer of electrons to oxygen is mediated by a membrane-bound heterodimer, comprising gp91phox and p22phox subunits. Deficiency of either subunit leads to severe immunodeficiency. We describe Eros (essential for reactive oxygen species), a protein encoded by the previously undefined mouse gene bc017643, and show that it is essential for host defense via the phagocyte NAPDH oxidase. Eros is required for expression of the NADPH oxidase components, gp91phox and p22phox. Consequently, Eros-deficient mice quickly succumb to infection. Eros also contributes to the formation of neutrophil extracellular traps (NETS) and impacts on the immune response to melanoma metastases. Eros is an ortholog of the plant protein Ycf4, which is necessary for expression of proteins of the photosynthetic photosystem 1 complex, itself also an NADPH oxio-reductase. We thus describe the key role of the previously uncharacterized protein Eros in host defense. PMID:28351984

Dysregulation of the Cytokine GM-CSF Induces Spontaneous Phagocyte Invasion and Immunopathology in the Central Nervous System.

PubMed

Spath, Sabine; Komuczki, Juliana; Hermann, Mario; Pelczar, Pawel; Mair, Florian; Schreiner, Bettina; Becher, Burkhard

2017-02-21

Chronic inflammatory diseases are influenced by dysregulation of cytokines. Among them, granulocyte macrophage colony stimulating factor (GM-CSF) is crucial for the pathogenic function of T cells in preclinical models of autoimmunity. To study the impact of dysregulated GM-CSF expression in vivo, we generated a transgenic mouse line allowing the induction of GM-CSF expression in mature, peripheral helper T (Th) cells. Antigen-independent GM-CSF release led to the invasion of inflammatory myeloid cells into the central nervous system (CNS), which was accompanied by the spontaneous development of severe neurological deficits. CNS-invading phagocytes produced reactive oxygen species and exhibited a distinct genetic signature compared to myeloid cells invading other organs. We propose that the CNS is particularly vulnerable to the attack of monocyte-derived phagocytes and that the effector functions of GM-CSF-expanded myeloid cells are in turn guided by the tissue microenvironment. Copyright © 2017 Elsevier Inc. All rights reserved.

Contribution of the autolysin AtlA to the bactericidal activity of amoxicillin against Enterococcus faecalis JH2-2.

PubMed

Bravetti, Anne-Lise; Mesnage, Stéphane; Lefort, Agnès; Chau, Françoise; Eckert, Catherine; Garry, Louis; Arthur, Michel; Fantin, Bruno

2009-04-01

The bactericidal activity of amoxicillin was investigated against Enterococcus faecalis JH2-2 and against an isogenic mutant deficient in the production of the N-acetylglucosaminidase AtlA. Comparison of the two strains indicated that this autolysin contributes to killing by amoxicillin both in vitro and in a rabbit model of experimental endocarditis.

Effect of primycin on growth-arrested cultures and cell integrity of Staphylococcus aureus.

PubMed

Feiszt, Péter; Schneider, György; Emődy, Levente

2017-06-01

Bactericidal effect against non-dividing bacteria is a very advantageous, but rare characteristic among antimicrobial agents, mostly possessed by those affecting the cell membrane. These kinds of agents can kill bacterial cells without lysis. We assessed these characteristics on primycin, a topical anti-staphylococcal agent highly effective against prevalent multiresistant strains, as it also acts on the cell membrane. In time-kill studies, primycin preserved its bactericidal activity against growth-arrested Staphylococcus aureus cultures. The bactericidal action was slower against growth-arrested cultures compared to the exponentially growing ones to different extents depending on the manner of arrest. The bactericidal effect was less influenced by stringent response and by protein synthesis inhibition, proving that it does not depend on metabolic activity. In contrast, uncoupling of the membrane potential predominantly slowed, and low temperature almost stopped killing of bacteria. In consideration of published data, these facts suggest that the antibacterial action of primycin involves disrupting of the membrane potential, and is predominantly influenced by the membrane fluidity. Optical density measurements and transmission electron microscopy verified that primycin kills bacterial cells without lysis. These results reveal favorable characteristics of primycin and point to, and broaden the knowledge on its membrane-targeted effect.

Multi-residue screening of prioritised human pharmaceuticals, illicit drugs and bactericides in sediments and sludge.

PubMed

Langford, Katherine H; Reid, Malcolm; Thomas, Kevin V

2011-08-01

A robust multi-residue method was developed for the analysis of a selection of pharmaceutical compounds, illicit drugs and personal care product bactericides in sediments and sludges. Human pharmaceuticals were selected for analysis in Scottish sewage sludge and freshwater sediments based on prescription, physico-chemical and occurrence data. The method was suitable for the analysis of the selected illicit drugs amphetamine, benzoylecgonine, cocaine, and methamphetamine, the pharmaceuticals atenolol, bendroflumethiazide, carbamazepine, citalopram, diclofenac, fluoxetine, ibuprofen, and salbutamol, and the bactericides triclosan and triclocarban in sewage sludge and freshwater sediment. The method provided an overall recovery of between 56 and 128%, RSDs of between 2 and 19% and LODs of between 1 and 50 ng g(-1). Using the methodology the human pharmaceuticals atenolol, carbamazepine and citalopram and the bactericides triclosan and triclocarban were detected in Scottish sewage sludge. The illicit drugs cocaine, its metabolite benzoylecgonine, amphetamine and methamphetamine were not detected in any of the samples analysed. Triclosan and triclocarban were present at the highest concentrations with triclocarban detected in all but one sample and showing a pattern of co-occurrence in both sludge and sediment samples.

Bactericidal effect of TiO2 photocatalyst on selected food-borne pathogenic bacteria.

PubMed

Kim, Byunghoon; Kim, Dohwan; Cho, Donglyun; Cho, Sungyong

2003-07-01

Titanium dioxide (TiO(2)) photocatalysts have attracted great attention as a material for photocatalytic sterilization in the food and environmental industry. This research aimed to design a new photobioreactor and its application to sterilize selected food borne pathogenic bacteria, Salmonella choleraesuis subsp., Vibrio parahaemolyticus, and Listeria monocytogenes. The photocatalytic reaction was carried out with various TiO(2) concentrations and Ultraviolet (UV) illumination time. A feasible synergistic effect was found that the bactericidal effect of TiO(2) on all bacterial suspension after UV light irradiation was much higher than that of without TiO(2). As the concentration of TiO(2) increased to 1.0 mg/ml, bactericidal effect increased. However, the bactericidal effect was rapidly abbreviated at TiO(2) concentration higher than 1.25 mg/ml to all selected bacteria. UV illumination time affected drastically the viability of all bacteria with different death rate. Similar trends were obtained from S. choleraesuis subsp. and V. parahaemolyticus that their complete killing was achieved after 3 h of illumination. However, L. monocytogenes was more resistant and its death ratio was about 87% at that time.

Bactericidal effect of silver nanoparticles against propagation of Clavibacter michiganensis infection in Lycopersicon esculentum Mill.

PubMed

Rivas-Cáceres, Raymundo Rene; Luis Stephano-Hornedo, Jose; Lugo, Jorge; Vaca, Rocio; Del Aguila, Pedro; Yañez-Ocampo, Gustavo; Mora-Herrera, Martha Elena; Camacho Díaz, Luis Miguel; Cipriano-Salazar, Moisés; Alaba, Peter Adeniyi

2018-02-01

This study explored the use of silver nanoparticle as a bactericidal against the propagation of Clavibacter michiganensis onto tomatoes (Lycopersicon esculentum Mill). In Mexico, tomato production covers about 73% of the total vegetable production but it is affected by outbreak of bacteria canker caused by Clavibacter michiganensis subspecies michiganensis (Cmm). Silver ions possess inhibitor properties, bactericides and high specter antimicrobials. In this study, 6 groups of culture were prepared using 6 different petri dishes where silver nanoparticles of varying concentrations (120, 84, 48, 24, 12 and 0 μg) were added. Furthermore, each group was observed for 20 min, 1, 2, 12 and 24 h. The optimum concentration is 84 μg, which shows an average of 2 Cmm colonies after 20 min. Further increase to 120 μg shows no significant change. However, the average colonies was observed for 48 μg after 1, 2, 12, and 24 h. The obtained results indicate that silver nanoparticles are a promising inhibitor, bactericide and high a specter antimicrobial for treatment or prevention of Cmm. Copyright © 2017. Published by Elsevier Ltd.

Nanoparticles as Efflux Pump and Biofilm Inhibitor to Rejuvenate Bactericidal Effect of Conventional Antibiotics

NASA Astrophysics Data System (ADS)

Gupta, Divya; Singh, Ajeet; Khan, Asad U.

2017-07-01

The universal problem of bacterial resistance to antibiotic reflects a serious threat for physicians to control infections. Evolution in bacteria results in the development of various complex resistance mechanisms to neutralize the bactericidal effect of antibiotics, like drug amelioration, target modification, membrane permeability reduction, and drug extrusion through efflux pumps. Efflux pumps acquire a wide range of substrate specificity and also the tremendous efficacy for drug molecule extrusion outside bacterial cells. Hindrance in the functioning of efflux pumps may rejuvenate the bactericidal effect of conventional antibiotics. Efflux pumps also play an important role in the exclusion or inclusion of quorum-sensing biomolecules responsible for biofilm formation in bacterial cells. This transit movement of quorum-sensing biomolecules inside or outside the bacterial cells may get interrupted by impeding the functioning of efflux pumps. Metallic nanoparticles represent a potential candidate to block efflux pumps of bacterial cells. The application of nanoparticles as efflux pump inhibitors will not only help to revive the bactericidal effect of conventional antibiotics but will also assist to reduce biofilm-forming capacity of microbes. This review focuses on a novel and fascinating application of metallic nanoparticles in synergy with conventional antibiotics for efflux pump inhibition.

Structural effect of quaternary ammonium chitin derivatives on their bactericidal activity and specificity.

PubMed

Morkaew, Tirut; Pinyakong, Onruthai; Tachaboonyakiat, Wanpen

2017-08-01

The effect of the quaternary ammonium chitin structure on the bactericidal activity and specificity against Escherichia coli and Staphylococcus aureus was investigated. Quaternary ammonium chitins were synthesized by the separate acylation of chitin (CT) with carboxymethyl trimethylammonium chloride (CMA), 3-carboxypropyl trimethylammonium chloride (CPA) and N-dodecyl-N,N-(dimethylammonio)butyrate (DDMAB). The successful acylation was confirmed by newly formed ester linkage. All three derivatives had a higher surface charge than chitin due to the additional positively charged quaternary ammonium groups. The N-short alkyl substituent (methyl) of CTCMA and CTCPA increased the hydrophilicity whilst the N-long alkyl substituent (dodecyl) of CTDDMAB increased the hydrophobicity compared to chitin. Chitin did not exhibit any bactericidal activity, while CTCMA and CTCPA completely killed E. coli and S. aureus in 30 and 60min, respectively, and CTDDMAB completely killed S. aureus in 10min but did not kill E. coli after a 2-h exposure. Therefore, the N-short alkyl substituent was more effective for killing E. coli and the N-long alkyl substituent conferred specific bactericidal activity against S. aureus. Copyright © 2017 Elsevier B.V. All rights reserved.

Availability of the basal planes of graphene oxide determines whether it is antibacterial.

PubMed

Hui, Liwei; Piao, Ji-Gang; Auletta, Jeffrey; Hu, Kan; Zhu, Yanwu; Meyer, Tara; Liu, Haitao; Yang, Lihua

2014-08-13

There are significant controversies on the antibacterial properties of graphene oxide (GO): GO was reported to be bactericidal in saline, whereas its activity in nutrient broth was controversial. To unveil the mechanisms underlying these contradictions, we performed antibacterial assays under comparable conditions. In saline, bare GO sheets were intrinsically bactericidal, yielding a bacterial survival percentage of <1% at 200 μg/mL. Supplementing saline with ≤10% Luria-Bertani (LB) broth, however, progressively deactivated its bactericidal activity depending on LB-supplementation ratio. Supplementation of 10% LB made GO completely inactive; instead, ∼100-fold bacterial growth was observed. Atomic force microscopy images showed that certain LB components were adsorbed on GO basal planes. Using bovine serum albumin and tryptophan as well-defined model adsorbates, we found that noncovalent adsorption on GO basal planes may account for the deactivation of GO's bactericidal activity. Moreover, this deactivation mechanism was shown to be extrapolatable to GO's cytotoxicity against mammalian cells. Taken together, our observations suggest that bare GO intrinsically kills both bacteria and mammalian cells and noncovalent adsorption on its basal planes may be a global deactivation mechanism for GO's cytotoxicity.

Inhaled corticosteroid treatment for 6 months was not sufficient to normalize phagocytosis in asthmatic children.

PubMed

da Silva-Martins, Carmen Lívia Faria; Couto, Shirley Claudino; Muniz-Junqueira, Maria Imaculada

2013-08-30

Corticosteroids are the first-line therapy for asthma; however, the effect of corticosteroids on the innate immune system remains unclear. This study's objective was to evaluate the effect of inhaled corticosteroid therapy (ICT) on phagocytic functions. To evaluate the impact of ICT, the phagocytosis of Saccharomyces cerevisiae by blood monocytes and neutrophils and the production of superoxide anions were assessed before and after three and six months of ICT treatment in 58 children with persistent asthma and 21 healthy controls. We showed that the phagocytic capacity of monocytes and neutrophils that occurred via pattern recognition receptors or was mediated by complement and immunoglobulin receptors in asthmatic children before treatment was significantly lower than in healthy controls (p<0.05, Mann-Whitney test) and was not influenced by the severity of the clinical form of the disease. Although there was clinical improvement with treatment, ICT for 6 months was not sufficient to normalize phagocytosis by the phagocytes. Superoxide anion production was also decreased in the asthmatic children before treatment, and ICT normalized the O- production only for children with mild persistent asthma when assessed at baseline but caused this function to decrease after stimulation (p<0.05, Kruskal-Wallis test). Our data suggest that an immunodeficiency in phagocytes remained even after treatment. However, this immunodeficiency does not appear to correspond with the clinical evolution of asthma because an improvement in clinical parameters occurred.

Origin of the phagocytic respiratory burst and its role in gut epithelial phagocytosis in a basal chordate.

PubMed

Yang, Ping; Huang, Shengfeng; Yan, Xinyu; Huang, Guangrui; Dong, Xiangru; Zheng, Tingting; Yuan, Dongjuan; Wang, Ruihua; Li, Rui; Tan, Ying; Xu, Anlong

2014-05-01

The vertebrate phagocytic respiratory burst (PRB) is a highly specific and efficient mechanism for reactive oxygen species (ROS) production. This mechanism is mediated by NADPH oxidase 2 (NOX2) and used by vertebrate phagocytic leukocytes to destroy internalized microbes. Here we demonstrate the presence of the PRB in a basal chordate, the amphioxus Branchiostoma belcheri tsingtauense (bbt). We show that using the antioxidant NAC to scavenge the production of ROS significantly decreased the survival rates of infected amphioxus, indicating that ROS are indispensable for efficient antibacterial responses. Amphioxus NOX enzymes and cytosolic factors were found to colocalize in the epithelial cells of the gill, intestine, and hepatic cecum and could be upregulated after exposure to microbial pathogens. The ROS production in epithelial cell lysates could be reconstructed by supplementing recombinant cytosolic factors, including bbt-p47phox, bbt-p67phox, bbt-p47phox, and bbt-Rac; the restored ROS production could be inhibited by anti-bbt-NOX2 and anti-bbt-p67phox antibodies. We also reveal that the gut epithelial lining cells of the amphioxus are competent at bacterial phagocytosis, and there is evidence that the PRB machinery could participate in the initiation of this phagocytic process. In conclusion, we report the presence of the classical PRB machinery in nonvertebrates and provide the first evidence for the possible role of PRB in epithelial cell immunity and phagocytosis. Copyright © 2014 Elsevier Inc. All rights reserved.

Role of the phagocytes on embryos: some morphological aspects.

PubMed

Da Silva, José Roberto Machado Cunha

2002-06-15

Phagocytosis in embryos was studied by Elie Metchnikoff more than a century ago and is a pillar of the Phagocytic Theory. Throughout the last three decades phagocytosis in embryos has been studied from different perspectives, which this review describes and analyzes. The following branches were identified: 1) the search for the origin and first identification of well-known adult phagocytes in embryos, including their role after induced injuries; 2) the search for the occurrence of phagocytosis in embryos and its role during their physiological development; and 3) the search for phagocytosis in embryos, as a tool to study identity and self-recognition. It is possible to verify that different cell types are able to undertake phagocytosis, under a variety of different stimuli, and that the nature of what is phagocytosed also varies widely. Although the overwhelming majority of species described among metazoarians are invertebrates, most published articles in this field relate to mammals (particularly mice and humans) and birds (particularly chicks). In order to enrich this field of knowledge, research using a wider variety of vertebrate and invertebrate species should be undertaken. Furthermore, the present knowledge of phagocytosis in embryos needs a revised paradigm capable of embracing all the above-mentioned research trends under a single, more general, biological theory. In this sense, Metchnikoff's Phagocytic Theory, which is based on a broad biological paradigm and is thus capable of dealing with all research trends mentioned herein, should be revisited in order to contribute to this edification. Copyright 2002 Wiley-Liss, Inc.

In vitro immunotoxicity assessment of culture-derived extracellular vesicles in human monocytes

PubMed Central

Rosas, Lucia E.; Elgamal, Ola A.; Mo, Xiaokui; Phelps, Mitch A.; Schmittgen, Thomas D.; Papenfuss, Tracey L.

2016-01-01

The potential to engineer extracellular vesicles (EV) that target specific cells and deliver a therapeutic payload has propelled a growing interest in their development as promising therapeutics. These EV are often produced from cultured cells. Very little is known about the interaction of cell culture-derived EV with cells of the immune system and their potential immunomodulatory effects. The present study evaluated potential immunotoxic effects of HEK293T-derived EV on the human monocytic cell lines THP-1 and U937. Incubation of cells with different doses of EV for 16–24 h was followed by assessment of cytotoxicity and cell function by flow cytometry. Changes in cell functionality were evaluated by the capacity of cells to phagocytize fluorescent microspheres. In addition, the internalization of labeled EV in THP-1 and U937 cells was evaluated. Exposure to EV did not affect the viability of THP-1 or U937 cells. Although lower doses of the EV increased phagocytic capacity in both cell lines, phagocytic efficiency of individual cells was not affected by EV exposure at any of the doses evaluated. This study also demonstrated that THP-1 and U937 monocytic cells are highly permissive to EV entry in a dose-response manner. These results suggest that, although HEK293T-derived EV are efficiently internalized by human monocytic cells, they do not exert a cytotoxic effect or alter phagocytic efficiency on the cell lines evaluated. PMID:27075513

The immunomodulatory effect of Zingiber cassumunar ethanolic extract on phagocytic activity, nitrit oxide and reaxtive oxygen intermediate secretions of macrophage in mice

NASA Astrophysics Data System (ADS)

Nurkhasanah; Santoso, R. D.; Fauziah, R.

2017-11-01

Immunomodulators could protect the body from a variety of infectious agents and boost immunity. Zingiber cassumunar rhizome or bangle potentially showed as an immunomodulator through increasing of macrophage activity in vitro. The objective of the study was to determine the effect of Z. cassumunar rhizome ethanolic extract on phagocytic activity, nitrite oxide (NO) and reactive oxygen intermediate (ROI) secretions in macrophages in vivo. A total of 200 g of Z. cassumunar rhizome was powdered, macerated in 96% ethanol and evaporated to get concentrated extract. Mice were divided into 5 groups as follow: the normal group was given by water only, the negative control group was given by a 0.94% CMC-Na suspension, the treatment groups were given by 250, 500 and 1000 mg/kgBW, respectively, of Z. cassumunar ethanolic extract. The extract was administered orally for 7 days. On the 8th day the mice were injected intraperitoneally 0.7 mg/kg BW of lipopolysaccharide. Four hours later macrophage was isolated. Furthermore, the determination of the phagocytic activity, NO and ROI secretions levels of macrophage were performed. The treatments of 250, 500 and 1000 mg/kg BW of Z. cassumunar ethanolic extract significantly increase the ROI and NO secretions levels (p<0.05), but did not increase the phagocytic activity (p>0.05) of macrophage. Z. cassumunar ethanolic extract have immunomodulatory effect in vivo.

CD77 levels over enzyme replacement treatment in Fabry Disease Family (V269M).

PubMed

Pereira, Ester Miranda; Silva, Adalberto Socorro da; Silva, Raimundo Nonato da; Monte Neto, José Tiburcio; Nascimento, Fernando F do; Sousa, Jackeline L M; Costa Filho, Henrique César Saraiva de Arêa Leão; Sales Filho, Herton Luiz Alves; Labilloy, Anatalia; Monte, Semiramis Jamil Hadad do

2018-06-04

Fabry disease (FD) is a disorder caused by mutations in the gene encoding for lysosomal enzyme α-galactosidase A (α-GAL). Reduced α-GAL activity leads to progressive accumulation of globotriaosylceramide (Gb3), also known as CD77. The recent report of increased expression of CD77 in blood cells of patients with FD indicated that this molecule can be used as a potential marker for monitoring enzyme replacement therapy (ERT). The purpose of this study was to evaluate the CD77 levels throughout ERT in FD patients (V269M mutation). We evaluated the fluctuations in PBMC (peripheral blood mononuclear cell) membrane CD77 expression in FD patients undergoing ERT and correlated these levels with those observed in different cell types. A greater CD77 expression was found in phagocytes of patients compared to controls at baseline. Interestingly, the variability in CD77 levels is larger in patients at baseline (340 - 1619 MIF) and after 12 months of ERT (240 - 530 MIF) compared with the control group (131 - 331 MFI). Furthermore, by analyzing the levels of CD77 in phagocytes from patients throughout ERT, we found a constant decrease in CD77 levels. The increased CD77 levels in the phagocytes of Fabry carriers together with the decrease in CD77 levels throughout ERT suggest that measuring CD77 levels in phagocytes is a promising tool for monitoring the response to ERT in FD.

Chemical studies on damages of Escherichea coli by the immune bactericidal reaction. II. Release of phosphatidylethanolamine from a phospholipase A-deficient mutant of E. coli during the immune bactericidal reaction.

PubMed

Inoue, K; Yano, K; Amano, T

1974-12-01

When an antibody-sensitized, phospholipase A-deficient mutant of Escherichia coli B/SM was treated with complement in the absence of lysozyme, bacterial phosphatidylethanolamine (PE) was liberated into the lipid fraction of the surrounding medium, but only traces of its degradation products were found in this fraction. Therefore, most of the degradation of bacterial PE to FFA and LPE observed in the usual immune bactericidal reaction (Inoue et al., 1974) must be the result of the action of bacterial phospholipase A which is activated or becomes accessible to its substrate on formation of lesions by complement. The mechanism of complement-mediated formation of membrane lesions is discussed on the basis of these results.

The effect of polyhexamethylene guanidine hydrochloride (PHMG) derivatives introduced into polylactide (PLA) on the activity of bacterial enzymes.

PubMed

Walczak, Maciej; Richert, Agnieszka; Burkowska-But, Aleksandra

2014-11-01

The present study was aimed at investigating bactericidal properties of polylactide (PLA) films containing three different polyhexamethylene guanidine hydrochloride (PHMG) derivatives and effect of the derivatives on extracellular hydrolytic enzymes and intracellular dehydrogenases. All PHMG derivatives had a slightly stronger bactericidal effect on Staphylococcus aureus than on E. coli but only PHMG granular polyethylene wax (at the concentration of at least 0.6 %) has a bactericidal effect. PHMG derivatives introduced into PLA affected the activity of microbial hydrolases to a small extent. This means that the introduction of PHMG derivatives into PLA will not reduce its enzymatic biodegradation significantly. On the other hand, PHMG derivatives introduced into PLA strongly affected dehydrogenases activity in S. aureus than in E. coli.

Obesity Increases Sensitivity to Endotoxin Liver Injury: Implications for the Pathogenesis of Steatohepatitis

NASA Astrophysics Data System (ADS)

Yang, Shi Qi; Zhi Lin, Hui; Lane, M. Daniel; Clemens, Mark; Diehl, Anna Mae

1997-03-01

Genetically obese fatty/fatty rats and obese/obese mice exhibit increased sensitivity to endotoxin hepatotoxicity, quickly developing steatohepatitis after exposure to low doses of lipopolysaccharide (LPS). Among obese animals, females are more sensitive to endotoxin liver injury than males. LPS induction of tumor necrosis factor α (TNFα ), the proven affecter of endotoxin liver injury, is no greater in the livers, white adipose tissues, or sera of obese animals than in those of lean controls. Indeed, the lowest serum concentrations of TNF occur in female obese rodents, which exhibit the most endotoxin-induced liver injury. Several cytokines that modulate the biological activity of TNF are regulated abnormally in the livers of obese animals. After exposure to LPS, mRNA of interferon γ , which sensitizes hepatocytes to TNF toxicity, is overexpressed, and mRNA levels of interleukin 10, a TNF inhibitor, are decreased. The phagocytic activity of liver macrophages and the hepatic expression of a gene encoding a macrophage-specific receptor are also decreased in obesity. This new animal model of obesity-associated liver disease demonstrates that hepatic macrophage dysfunction occurs in obesity and suggests that this might promote steatohepatitis by sensitizing hepatocytes to endotoxin.

Distribution and clinical aspects of primary immunodeficiencies in a Taiwan pediatric tertiary hospital during a 20-year period.

PubMed

Lee, Wen-I; Kuo, Ming-Ling; Huang, Jing-Long; Lin, Syh-Jae; Wu, Cheng-Jang

2005-03-01

Recent advances in immunologic techniques have lead to increased recognition of primary immunodeficiencies. A review of patients with suspected immunodeficiencies in a Taiwan tertiary hospital from January 1985 to October 2004 and molecular/genetic analyses done on some patients were investigated. Of the 403 patients selected based on the International Classification of Disease, Ninth Revision, 37 patients with PID (8 females and 29 males) were identified: 17 (46%) with antibody production deficiencies, nine (24%) with defective phagocyte function, four (11%) with combined B and T cell immunodeficiencies, seven (19%) with T cell deficiencies, but none with primary complement deficiencies. Those with secondary immunodeficiencies were excluded from the study. Recurrent sinopulmonary infections (62%) were the most common clinical manifestation, followed by sepsis (57%), severe skin infection (40%), splenomegaly/hepatomegaly (27%), central nervous system dysfunction (22%), chronic diarrhea (22%), and failure to thrive (19%). Seven (19%) patients died, five of infections, one of disseminated intravascular coagulopathy and one of hepatocellular carcinoma. Six novel mutations were found from 11 agreed patients. This is the first report on primary immunodeficiencies in Taiwan covering a 20-year period.

Rac-1 as a new therapeutic target in cerebro- and cardio-vascular diseases.

PubMed

Carrizzo, Albino; Forte, Maurizio; Lembo, Maria; Formisano, Luigi; Puca, Annibale A; Vecchione, Carmine

2014-01-01

Growing evidence indicates that overproduction of reactive oxygen species (ROS) plays a prominent role in the development of cardio- and cerebro-vascular diseases. Among the mechanisms identified to produce oxidative stress in the vascular wall, those mediated by membrane-bound NAD(P)H oxidases represent a major one. NAD(P)H oxidases are a family of enzymes that generate ROS both in phagocytic and non-phagocytic cell types. Vascular NAD(P)H oxidase contains the membrane-bound subunits Nox1, Nox2 (gp91phox), Nox4 and p22phox, the catalytic site of the oxidase, and the cytosolic components p47phox and p67phox. Rac1 (Ras-related C3 botulinum toxin substrate1) is a small GTPase essential for the assembly and activation of NADPH oxidase. Several molecular and cellular studies have reported the involvement of Rac1 in different cardiovascular pathologies, such as vascular smooth muscle proliferation, cardiomyocyte hypertrophy, endothelial cell shape change, atherosclerosis and endothelial dysfunction in hypertension. In addition, increased activation of NADPH oxidase by Rac1 has been reported in animals and humans after myocardial infarction and heart failure. The Rac1/NADPH pathway has also been found involved in different pathologies of the cerebral district, such as ischemic stroke, cognitive impairment, subaracnoid hemorrhage and neuronal oxidative damage typical of several neurodegenerative disorders. In addition, thrombotic events are an important step in the onset of cardio- and cerebrovascular diseases. Rac1 has been found involved also in platelet activation, inducing actin polymerization and lamellipodia formation, which are necessary steps for platelet aggregation. Taken together, the evidence candidates Rac1 as a new pharmacological target of cardiovascular and cerebrovascular diseases. Although the involvement of Rac1 in the beneficial pleiotropic effects of drugs such as statins is well known, and the onset of numerous side effects has raised concern for the management of some patient groups. Interestingly, a novel selective Rac1 inhibitor, NSC23766, has recently been introduced; its use has been reported mainly in the oncology field. Future studies are needed to extend its application to cardio- and cerebro-vascular diseases, and translate its use to humans.

Corneal epithelial wound healing and bactericidal effect of conditioned medium from human uterine cervical stem cells.

PubMed

Bermudez, Maria A; Sendon-Lago, Juan; Eiro, Noemi; Treviño, Mercedes; Gonzalez, Francisco; Yebra-Pimentel, Eva; Giraldez, Maria Jesus; Macia, Manuel; Lamelas, Maria Luz; Saa, Jorge; Vizoso, Francisco; Perez-Fernandez, Roman

2015-01-22

To evaluate the effect of conditioned medium from human uterine cervical stem cells (CM-hUCESCs) on corneal epithelial healing in a rat model of dry eye after alkaline corneal epithelial ulcer. We also tested the bactericidal effect of CM-hUCESCs. Dry eye was induced in rats by extraocular lacrimal gland excision, and corneal ulcers were produced using NaOH. Corneal histologic evaluation was made with hematoxylin-eosin (H&E) staining. Real-time PCR was used to evaluate mRNA expression levels of proinflammatory cytokines. We also studied the bactericidal effect of CM-hUCESCs in vitro and on infected corneal contact lenses (CLs) using Escherichia coli and Staphylococcus epidermidis bacteria. In addition, in order to investigate proteins from CM-hUCESCs that could mediate these effects, we carried out a human cytokine antibody array. After injury, dry eyes treated with CM-hUCESCs significantly improved epithelial regeneration and showed reduced corneal macrophage inflammatory protein-1 alpha (MIP-1α) and TNF-α mRNA expression as compared to untreated eyes and eyes treated with culture medium or sodium hyaluronate ophthalmic drops. In addition, we found in CM-hUCESCs high levels of proteins, such as tissue inhibitors of metalloproteinases 1 and 2, fibroblast growth factor 6 and 7, urokinase receptor, and hepatocyte growth factor, that could mediate these effects. In vitro, CM-hUCESCs showed a clear bactericidal effect on both E. coli and S. epidermidis and CLs infected with S. epidermidis. Analyses of CM-hUCESCs showed elevated levels of proteins that could be involved in the bactericidal effect, such as the chemokine (C-X-C motif) ligands 1, 6, 8, 10, and the chemokine (C-C motif) ligands 5 and 20. Treatment with CM-hUCESCs improved wound healing of alkali-injured corneas and showed a strong bactericidal effect on CLs. Patients using CLs and suffering from dry eye, allergies induced by commercial solutions, or small corneal injuries could benefit from this treatment. Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

Mechanisms of Action of Escapin, a Bactericidal Agent in the Ink Secretion of the Sea Hare Aplysia californica: Rapid and Long-Lasting DNA Condensation and Involvement of the OxyR-Regulated Oxidative Stress Pathway

PubMed Central

Ko, Ko-Chun; Tai, Phang C.

2012-01-01

The marine snail Aplysia californica produces escapin, an l-amino acid oxidase, in its defensive ink. Escapin uses l-lysine to produce diverse products called escapin intermediate products of l-lysine (EIP-K), including α-amino-ε-caproic acid, Δ1-piperidine-2-carboxylic acid, and Δ2-piperidine-2-carboxylic acid. EIP-K and H2O2 together, but neither alone, is a powerful bactericide. Here, we report bactericidal mechanisms of escapin products on Escherichia coli. We show that EIP-K and H2O2 together cause rapid and long-lasting DNA condensation: 2-min treatment causes significant DNA condensation and killing, and 10-min treatment causes maximal effect, lasting at least 70 h. We isolated two mutants resistant to EIP-K plus H2O2, both having a single missense mutation in the oxidation regulatory gene, oxyR. A complementation assay showed that the mutated gene, oxyR(A233V), renders resistance to EIP-K plus H2O2, and a gene dosage effect leads to reduction of resistance for strains carrying wild-type oxyR. Temperature stress with EIP-K does not produce the bactericidal effect, suggesting the effect is due to a specific response to oxidative stress. The null mutant for any single DNA-binding protein—Dps, H-NS, Hup, Him, or MukB—was not resistant to EIP-K plus H2O2, suggesting that no single DNA-binding protein is necessary to mediate this bactericidal effect, but allowing for the possibility that EIP-K plus H2O2 could function through a combination of DNA-binding proteins. The bactericidal effect of EIP-K plus H2O2 was eliminated by the ferrous ion chelator 1,10-phenanthroline, and it was reduced by the hydroxyl radical scavenger thiourea, suggesting hydroxyl radicals mediate the effects of EIP-K plus H2O2. PMID:22232273

Are soluble factors relevant for polymorphonuclear leukocyte dysregulation in septicemia?

PubMed Central

Wenisch, C; Graninger, W

1995-01-01

Polymorphonuclear leukocytes (PMNs) of twelve patients with gram-negative septicemia exhibited a decreased capacity to phagocytize Escherichia coli and generate reactive oxygen products which normalized within 7 days of treatment. Ex vivo exchange of plasma from age-, sex-, and blood-group-identical normal controls resulted in an increase of both phagocytic capacity and reactive oxygen intermediate generation in PMNs of septicemic patients and transiently reduced phagocytosis and reactive oxygen intermediate production in PMNs of normal controls. These results suggest that extrinsic factors are crucial for PMN function. PMID:7697538

Hacker within! Ehrlichia chaffeensis Effector Driven Phagocyte Reprogramming Strategy

PubMed Central

Lina, Taslima T.; Farris, Tierra; Luo, Tian; Mitra, Shubhajit; Zhu, Bing; McBride, Jere W.

2016-01-01

Ehrlichia chaffeensis is a small, gram negative, obligately intracellular bacterium that preferentially infects mononuclear phagocytes. It is the etiologic agent of human monocytotropic ehrlichiosis (HME), an emerging life-threatening tick-borne zoonosis. Mechanisms by which E. chaffeensis establishes intracellular infection, and avoids host defenses are not well understood, but involve functionally relevant host-pathogen interactions associated with tandem and ankyrin repeat effector proteins. In this review, we discuss the recent advances in our understanding of the molecular and cellular mechanisms that underlie Ehrlichia host cellular reprogramming strategies that enable intracellular survival. PMID:27303657

Antibacterial activity of DLC films containing TiO2 nanoparticles.

PubMed

Marciano, F R; Lima-Oliveira, D A; Da-Silva, N S; Diniz, A V; Corat, E J; Trava-Airoldi, V J

2009-12-01

Diamond-like carbon (DLC) films have been the focus of extensive research in recent years due to their potential applications as surface coatings on biomedical devices. Titanium dioxide (TiO2) in the anatase crystalline form is a strong bactericidal agent when exposed to near-UV light. In this work we investigate the bactericidal activity of DLC films containing TiO2 nanoparticles. The films were grown on 316L stainless-steel substrates from a dispersion of TiO2 in hexane using plasma-enhanced chemical vapor deposition. The composition, bonding structure, surface energy, stress, and surface roughness of these films were also evaluated. The antibacterial tests were performed against Escherichia coli (E. coli) and the results were compared to the bacterial adhesion force to the studied surfaces. The presence of TiO2 in DLC bulk was confirmed by Raman spectroscopy. As TiO2 content increased, I(D)/I(G) ratio, hydrogen content, and roughness also increased; the films became more hydrophilic, with higher surface free energy and the interfacial energy of bacteria adhesion decreased. Experimental results show that TiO2 increased DLC bactericidal activity. Pure DLC films were thermodynamically unfavorable to bacterial adhesion. However, the chemical interaction between the E. coli and the studied films increased for the films with higher TiO2 concentration. As TiO2 bactericidal activity starts its action by oxidative damage to the bacteria wall, a decrease in the interfacial energy of bacteria adhesion causes an increase in the chemical interaction between E. coli and the films, which is an additional factor for the increasing bactericidal activity. From these results, DLC with TiO2 nanoparticles can be useful for producing coatings with antibacterial properties.

Antibacterial effects of ellagitannins from Acalypha wilkesiana var. macafeana hort.: surface morphology analysis with environmental scanning electron microscopy and synergy with antibiotics.

PubMed

Din, Wardah Mustafa; Jin, Khoo Teng; Ramli, Ramliza; Khaithir, Tzar Mohd Nizam; Wiart, Christophe

2013-09-01

The present study served to gain further insight into the bactericidal effects of ellagitannins from Acalypha wilkesiana var. macafeana hort. against pathogenic bacteria. Ellagitannins from the aerial parts of A. wilkesiana var. macafeana hort. (EAW) inhibited the growth of Bacillus cereus (ATCC 11778), Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 11632) and Methicillin-resistant Staphylococcus aureus (MRSA) clinical strain with inhibition zones equal to 11.01 ± 1.53 mm, 16.63 ± 0.11 mm, 11.40 ± 1.10 mm and 8.22 ± 0.19 mm, respectively. The minimal inhibition concentration and the minimal bactericidal concentration of ellagitannins from A. wilkesiana var. macafeana hort. (EAW) against MRSA were 750 µg/mL and 3000 µg/mL, respectively. We then examined the synergistic effect of EAW with three antibiotics, i.e. ampicillin, streptomycin and tetracycline, via the checkerboard assay and time-kill assay and observed that EAW is synergistic with ampicillin against S. aureus (ATCC 11632). Environmental electron scanning microscopy analysis showed cell lysis against S. aureus (ATCC 11632) upon treatment with the ellagitannin fraction. The ellagitannin fraction from A. wilkesiana var. macafeana hort. is bactericidal against gram-positive bacteria tested and works synergistically with ampicillin against S. aureus. Morphology analysis of the cell suggests that the bactericidal property of the ellagitannin fraction mechanism involves lysis of the cell wall. In summary, our studies demonstrate that A. wilkesiana var. macafeana hort. produces bactericidal ellagitannins of clinical and/or cosmetological value. Copyright © 2012 John Wiley & Sons, Ltd.

Bactericidal efficacy of elevated pH on fish pathogenic and environmental bacteria

USGS Publications Warehouse

Starliper, Clifford E.; Watten, Barnaby J.

2013-01-01

Ship ballast water is a recognized medium for transfer and introductions of nonindigenous species. There is a need for new ballast water treatment methods that effectively and safely eliminate or greatly minimize movements of these species. The present study employed laboratory methods to evaluate the bactericidal efficacy of increased pH (pH 10.0–12.0) for exposure durations of up to 72 h to kill a variety of Gram-negative and Gram-positive bacteria including fish pathogens (Aeromonas spp., Yersinia ruckeri, Edwardsiella ictaluri, Serratia liquefaciens, Carnobacterium sp.), other common aquatic-inhabitant bacteria (Serratia marcescens, Pseudomonas fluorescens, Staphylococcus sp., Bacillus sp.) and indicators listed in International Maritime Organization D2 Standards; namely, Vibrio cholera (an environmental isolate from fish), Escherichia coli and Enterococcus faecalis. Volumes of 5 N NaOH were added to tryptic soy broth to obtain desired pH adjustments. Viable cells were determined after 0, 4, 12, 24, 48, and 72 h. Initial (0 h) cell numbers ranged from 3.40 × 104 cfu/mL for Bacillus sp. to 2.44 × 107 cfu/mL for E. faecalis. The effective endpoints of pH and treatment duration necessary to realize 100% bactericidal effect varied; however, all bacteria tested were killed within 72 h at pH 12.0 or lower. The lowest parameters examined, 4 h at pH 10.0, were bactericidal to V. cholera, E. ictaluri, three of four isolates of E. coli, and (three of four) Aeromonas salmonicida subsp. salmonicida. Bactericidal effect was attained at pH 10.0 within 12 h for the other A. salmonicida subsp. salmonicida, and within 24 h for P. fluorescens, and the remaining E. coli.

Urinary bactericidal activity of single doses (250, 500, 750 and 1000 mg) of levofloxacin against fluoroquinolone-resistant strains of Escherichia coli.

PubMed

Stein, Gary E; Schooley, Sharon L; Nicolau, David P

2008-10-01

Increasing resistance to fluoroquinolones in uropathogens has become a clinical concern. The purpose of this study was to analyse the urinary bactericidal activity (UBA) of levofloxacin against fluoroquinolone-resistant strains of Escherichia coli. Ten healthy adult subjects (aged 23-60 years) received single doses of levofloxacin (250, 500, 750 and 1000 mg) and then blood and urine samples were collected in intervals (0-1.5, 1.5-4, 4-8, 8-12 and 12-24h) over 24h. Both serum and urine concentrations were measured by a validated high-performance liquid chromatography assay. Bactericidal titres in urine were determined against E. coli isolates with minimum inhibitory concentrations of 0.125, 4, 8, 16, 32 and 64microg/mL for levofloxacin. The mean serum pharmacokinetic parameters for these doses of levofloxacin were similar to previously published values. The mean peak urinary concentrations (0-1.5h) were 210, 347, 620 and 536microg/mL for the 250, 500, 750 and 1000 mg dose, respectively. Each dose of levofloxacin exhibited early (0-1.5h time period) bactericidal activity in urine in virtually all subjects against E. coli strains with MICs

Bactericidal Efficacy of Hydrogen Peroxide-Based Disinfectants Against Gram-Positive and Gram-Negative Bacteria on Stainless Steel Surfaces.

PubMed

Ríos-Castillo, Abel G; González-Rivas, Fabián; Rodríguez-Jerez, José J

2017-10-01

In order to develop disinfectant formulations that leverage the effectiveness of hydrogen peroxide (H 2 O 2 ), this study evaluated the bactericidal efficacy of hydrogen peroxide-based disinfectants against Gram-positive and Gram-negative bacteria on stainless steel surfaces. Low concentration of hydrogen peroxide as 0.5% with a cationic polymer, ethoxylated fatty alcohol, and ethyl alcohol had bactericidal efficacy (reductions ≥ 4 log 10 CFU/mL) against Escherichia coli, Staphylococcus aureus, Enterococcus hirae, and Pseudomonas aeruginosa. Hydrogen peroxide-based disinfectants were more effective against E. hirae and P. aeruginosa than to S. aureus. However, the efficacy of hydrogen peroxide against catalase positive bacteria such as S. aureus was increased when this compound was formulated with low concentrations of benzalkonium chloride or ethyl alcohol, lactic acid, sodium benzoate, cationic polymer, and salicylic acid. This study demonstrates that the use of hydrogen peroxide with other antimicrobial products, in adequate concentrations, had bactericidal efficacy in Gram-positive and Gram-negative bacteria on stainless steel surfaces, enabling to reduce the effective concentration of hydrogen peroxide. In the same way, the use of hydrogen peroxide-based disinfectants could reduce the concentrations of traditional disinfectants as quaternary ammonium compounds and therefore a reduction of their chemical residues in the environment after being used. The study of the bactericidal properties of environmentally nontoxic disinfectants such as hydrogen peroxide, sole or in formulations with other disinfectants against Gram-positive and Gram-negative bacteria can enhance the efficacy of various commonly used disinfectant formulations with the hygiene benefits that it entails. Also, the use of hydrogen peroxide formulations can reduce the concentration levels of products that generate environmental residues. © 2017 Institute of Food Technologists®.

Peptide fragments of a beta-defensin derivative with potent bactericidal activity.

PubMed

Reynolds, Natalie L; De Cecco, Martin; Taylor, Karen; Stanton, Chloe; Kilanowski, Fiona; Kalapothakis, Jason; Seo, Emily; Uhrin, Dusan; Campopiano, Dominic; Govan, John; Macmillan, Derek; Barran, Perdita; Dorin, Julia R

2010-05-01

Beta-defensins are known to be both antimicrobial and able to chemoattract various immune cells. Although the sequences of paralogous genes are not highly conserved, the core defensin structure is retained. Defb14-1C(V) has bactericidal activity similar to that of its parent peptide (murine beta-defensin Defb14) despite all but one of the canonical six cysteines being replaced with alanines. The 23-amino-acid N-terminal half of Defb14-1C(V) is a potent antimicrobial while the C-terminal half is not. Here, we use a library of peptide derivatives to demonstrate that the antimicrobial activity can be localized to a particular region. Overlapping fragments of the N-terminal region were tested for their ability to kill Gram-positive and Gram-negative bacteria. We demonstrate that the most N-terminal fragments (amino acids 1 to 10 and 6 to 17) are potent antimicrobials against Gram-negative bacteria whereas fragments based on sequence more C terminal than amino acid 13 have very poor activity against both Gram-positive and -negative types. We further test a series of N-terminal deletion peptides in both their monomeric and dimeric forms. We find that bactericidal activity is lost against both Gram types as the deletion region increases, with the point at which this occurs varying between bacterial strains. The dimeric form of the peptides is more resistant to the peptide deletions, but this is not due just to increased charge. Our results indicate that the primary sequence, together with structure, is essential in the bactericidal action of this beta-defensin derivative peptide and importantly identifies a short fragment from the peptide that is a potent bactericide.

Peptide Fragments of a β-Defensin Derivative with Potent Bactericidal Activity ▿

PubMed Central

Reynolds, Natalie L.; De Cecco, Martin; Taylor, Karen; Stanton, Chloe; Kilanowski, Fiona; Kalapothakis, Jason; Seo, Emily; Uhrin, Dusan; Campopiano, Dominic; Govan, John; Macmillan, Derek; Barran, Perdita; Dorin, Julia R.

2010-01-01

β-Defensins are known to be both antimicrobial and able to chemoattract various immune cells. Although the sequences of paralogous genes are not highly conserved, the core defensin structure is retained. Defb14-1CV has bactericidal activity similar to that of its parent peptide (murine β-defensin Defb14) despite all but one of the canonical six cysteines being replaced with alanines. The 23-amino-acid N-terminal half of Defb14-1CV is a potent antimicrobial while the C-terminal half is not. Here, we use a library of peptide derivatives to demonstrate that the antimicrobial activity can be localized to a particular region. Overlapping fragments of the N-terminal region were tested for their ability to kill Gram-positive and Gram-negative bacteria. We demonstrate that the most N-terminal fragments (amino acids 1 to 10 and 6 to 17) are potent antimicrobials against Gram-negative bacteria whereas fragments based on sequence more C terminal than amino acid 13 have very poor activity against both Gram-positive and -negative types. We further test a series of N-terminal deletion peptides in both their monomeric and dimeric forms. We find that bactericidal activity is lost against both Gram types as the deletion region increases, with the point at which this occurs varying between bacterial strains. The dimeric form of the peptides is more resistant to the peptide deletions, but this is not due just to increased charge. Our results indicate that the primary sequence, together with structure, is essential in the bactericidal action of this β-defensin derivative peptide and importantly identifies a short fragment from the peptide that is a potent bactericide. PMID:20176896

Synergistic antibacterial effects of β-lactam antibiotic combined with silver nanoparticles

NASA Astrophysics Data System (ADS)

Li, Ping; Li, Juan; Wu, Changzhu; Wu, Qingsheng; Li, Jian

2005-09-01

The bactericidal action of silver (0) nanoparticles and amoxicillin on Escherichia coli is studied, respectively. Increasing concentration of both amoxicillin (0-0.525 mg ml-1) and silver nanoparticles (0-40 µg ml-1) showed a higher antibacterial effect in Luria-Bertani (LB) medium. Escherichia coli cells have different bactericidal sensitivity to them. When amoxicillin and silver nanoparticles are combined, it results in greater bactericidal efficiency on Escherichia coli cells than when they were applied separately. Dynamic tests on bacterial growth indicated that exponential and stationary phases are greatly decreased and delayed in the synergistic effect of amoxicillin and silver nanoparticles. In addition, the effect induced by a preincubation with silver nanoparticles is examined. The results show that solutions with more silver nanoparticles have better antimicrobial effects. One hypothesized mechanism is proposed to explain this phenomenon.

Effect of amino acid substitution in the staphylococcal peptides warnericin RK and PSMα on their anti-Legionella and hemolytic activities.

PubMed

Marchand, Adrienne; Augenstreich, Jacques; Loiseau, Clémence; Verdon, Julien; Lecomte, Sophie; Berjeaud, Jean-Marc

2015-07-01

Warnericin RK from Staphylococcus warneri and PSMα from Staphylococcus epidermidis are anti-Legionella peptides which were differently classified in a previous study according to their mode of action. Indeed, warnericin RK is highly hemolytic with a bactericidal mode of action, whereas PSMα is poorly hemolytic with a bacteriostatic mode of action toward L. pneumophila. In order to find anti-Legionella peptides which are not hemolytic, a collection of peptides varying in sequence from warnericin RK to PSMα were designed and synthesized, and their anti-Legionella activities, in terms of growth inhibition, permeabilization, and bactericidal effect, as well as their hemolytic activities, were measured and compared. The results showed that some residues, at position 14 for both peptides for instance, were of major importance for bactericidal and hemolytic activities.

Fe-S cluster biosynthesis controls uptake of aminoglycosides in a ROS-less death pathway.

PubMed

Ezraty, Benjamin; Vergnes, Alexandra; Banzhaf, Manuel; Duverger, Yohann; Huguenot, Allison; Brochado, Ana Rita; Su, Shu-Yi; Espinosa, Leon; Loiseau, Laurent; Py, Béatrice; Typas, Athanasios; Barras, Frédéric

2013-06-28

All bactericidal antibiotics were recently proposed to kill by inducing reactive oxygen species (ROS) production, causing destabilization of iron-sulfur (Fe-S) clusters and generating Fenton chemistry. We find that the ROS response is dispensable upon treatment with bactericidal antibiotics. Furthermore, we demonstrate that Fe-S clusters are required for killing only by aminoglycosides. In contrast to cells, using the major Fe-S cluster biosynthesis machinery, ISC, cells using the alternative machinery, SUF, cannot efficiently mature respiratory complexes I and II, resulting in impendence of the proton motive force (PMF), which is required for bactericidal aminoglycoside uptake. Similarly, during iron limitation, cells become intrinsically resistant to aminoglycosides by switching from ISC to SUF and down-regulating both respiratory complexes. We conclude that Fe-S proteins promote aminoglycoside killing by enabling their uptake.

Comparative in vitro susceptibilities and bactericidal activities of investigational fluoroquinolone ABT-492 and other antimicrobial agents against human mycoplasmas and ureaplasmas.

PubMed

Waites, Ken B; Crabb, Donna M; Duffy, Lynn B

2003-12-01

We determined in vitro susceptibilities for ABT-492 and other antimicrobials against Mycoplasma pneumoniae, Mycoplasma fermentans, Mycoplasma hominis, and Ureaplasma species. ABT-492 MICs were < or =1 microg/ml, and the agent was bactericidal against selected isolates of M. pneumoniae and M. hominis. ABT-492 has potential for treatment of infections due to these microorganisms.

In vitro and bactericidal activities of ABT-492, a novel fluoroquinolone, against Gram-positive and Gram-negative organisms.

PubMed

Almer, Laurel S; Hoffrage, Jennifer B; Keller, Erika L; Flamm, Robert K; Shortridge, Virginia D

2004-07-01

In vitro activities of ABT-492, ciprofloxacin, levofloxacin, trovafloxacin, moxifloxacin, gatifloxacin, and gemifloxacin were compared. ABT-492 was more potent against quinolone-susceptible and -resistant gram-positive organisms, had activity similar to that of ciprofloxacin against certain members of the family Enterobacteriaceae, and had comparable activity against quinolone-susceptible, nonfermentative, gram-negative organisms. Bactericidal activity of ABT-492 was also evaluated.

Comparative In Vitro Susceptibilities and Bactericidal Activities of Investigational Fluoroquinolone ABT-492 and Other Antimicrobial Agents against Human Mycoplasmas and Ureaplasmas

PubMed Central

Waites, Ken B.; Crabb, Donna M.; Duffy, Lynn B.

2003-01-01

We determined in vitro susceptibilities for ABT-492 and other antimicrobials against Mycoplasma pneumoniae, Mycoplasma fermentans, Mycoplasma hominis, and Ureaplasma species. ABT-492 MICs were ≤1 μg/ml, and the agent was bactericidal against selected isolates of M. pneumoniae and M. hominis. ABT-492 has potential for treatment of infections due to these microorganisms. PMID:14638513

Green-Tea and Epigallocatechin-3-Gallate are Bactericidal against Bacillus anthracis

DTIC Science & Technology

2017-06-13

EGCG, catechins such 245 as epigallocatechin and epicatechin gallate are also antibacterial agents. Moreover, the 246 bactericidal activity of green...Sharma A, Gupta S, Sarethy IP, Dang S, Gabrani R. 2012. Green tea extract: possible mechanism 285 and antibacterial activity on skin pathogens. Food...was shown to be responsible for this activity , against 30 both the attenuated B. anthracis ANR and the virulent, encapsulated strain B. anthracis

Bactericidal active ingredient in cryopreserved plasma-treated water with the reduced-pH method for plasma disinfection

NASA Astrophysics Data System (ADS)

Kitano, Katsuhisa; Ikawa, Satoshi; Nakashima, Yoichi; Tani, Atsushi; Yokoyama, Takashi; Ohshima, Tomoko

2016-09-01

For the plasma disinfection of human body, plasma sterilization in liquid is crucial. We found that the plasma-treated water (PTW) has strong bactericidal activity under low pH condition. Physicochemical properties of PTW is discussed based on chemical kinetics. Lower temperature brings longer half-life and the bactericidal activity of PTW can be kept by cryopreservation. High performance PTW, corresponding to the disinfection power of 22 log reduction (B. subtilis spore), can be obtained by special plasma system equipped with cooling device. This is equivalent to 65% H2O2, 14% sodium hypochlorite and 0.33% peracetic acid, which are deadly poison for human. But, it is deactivated soon at higher temperature (4 sec. at body temperature), and toxicity to human body seems low. For dental application, PTW was effective on infected models of human extracted tooth. Although PTW has many chemical components, respective chemical components in PTW were isolated by ion chromatography. In addition to peaks of H2O2, NO2- and NO3-, a specific peak was detected. and only this fraction had bactericidal activity. Purified active ingredient of PTW is the precursor of HOO, and further details will be discussed in the presentation. MEXT (15H03583, 23340176, 25108505). NCCE (23-A-15).

Bactericidal activities of woven cotton and nonwoven polypropylene fabrics coated with hydroxyapatite-binding silver/titanium dioxide ceramic nanocomposite “Earth-plus”

PubMed Central

Kasuga, Eriko; Kawakami, Yoshiyuki; Matsumoto, Takehisa; Hidaka, Eiko; Oana, Kozue; Ogiwara, Naoko; Yamaki, Dai; Sakurada, Tsukasa; Honda, Takayuki

2011-01-01

Background Bacteria from the hospital environment, including linens and curtains, are often responsible for hospital-associated infections. The aim of the present study was to evaluate the bactericidal effects of fabrics coated with the hydroxyapatite-binding silver/titanium dioxide ceramic nanocomposite “Earth-plus”. Methods Bactericidal activities of woven and nonwoven fabrics coated with Earth-plus were investigated by the time-kill curve method using nine bacterial strains, including three Staphylococcus aureus, three Escherichia coli, and three Pseudomonas aeruginosa strains. Results The numbers of viable S. aureus and E. coli cells on both fabrics coated with Earth-plus decreased to below 2 log10 colony-forming units/mL in six hours and reached the detection limit in 18 hours. Viable cell counts of P. aeruginosa on both fabrics coated with Earth-plus could not be detected after 3–6 hours. Viable cells on woven fabrics showed a more rapid decline than those on nonwoven fabrics. Bacterial cell counts of the nine strains on fabrics without Earth-plus failed to decrease even after 18 hours. Conclusion Woven cotton and nonwoven polypropylene fabrics were shown to have excellent antibacterial potential. The woven fabric was more bactericidal than the nonwoven fabric. PMID:21931489

Phagocytosis, bacterial killing, and cytokine activation of circulating blood neutrophils in horses with severe equine asthma and control horses.

PubMed

Vanderstock, Johanne M; Lecours, Marie-Pier; Lavoie-Lamoureux, Annouck; Gottschalk, Marcelo; Segura, Mariela; Lavoie, Jean-Pierre; Jean, Daniel

2018-04-01

OBJECTIVE To evaluate in vitro phagocytosis and bactericidal activity of circulating blood neutrophils in horses with severe equine asthma and control horses and to determine whether circulating blood neutrophils in horses with severe equine asthma have an increase in expression of the proinflammatory cytokine tumor necrosis factor (TNF)-α and the chemokine interleukin (IL)-8 and a decrease in expression of the anti-inflammatory cytokine IL-10 in response to bacteria. ANIMALS 6 horses with severe equine asthma and 6 control horses. PROCEDURES Circulating blood neutrophils were isolated from horses with severe equine asthma and control horses. Phagocytosis was evaluated by use of flow cytometry. Bactericidal activity of circulating blood neutrophils was assessed by use of Streptococcus equi and Streptococcus zooepidemicus as targets, whereas the cytokine mRNA response was assessed by use of a quantitative PCR assay. RESULTS Circulating blood neutrophils from horses with severe equine asthma had significantly lower bactericidal activity toward S zooepidemicus but not toward S equi, compared with results for control horses. Phagocytosis and mRNA expression of TNF-α, IL-8, and IL-10 were not different between groups. CONCLUSIONS AND CLINCAL RELEVANCE Impairment of bactericidal activity of circulating blood neutrophils in horses with severe equine asthma could contribute to an increased susceptibility to infections.

Damage of Escherichia coli membrane by bactericidal agent polyhexamethylene guanidine hydrochloride: micrographic evidences.

PubMed

Zhou, Z X; Wei, D F; Guan, Y; Zheng, A N; Zhong, J J

2010-03-01

The purpose of this study was to provide micrographic evidences for the damaged membrane structure and intracellular structure change of Escherichia coli strain 8099, induced by polyhexamethylene guanidine hydrochloride (PHMG). The bactericidal effect of PHMG on E. coli was investigated based on beta-galactosidase activity assay, fluorescein-5-isothiocyanate confocal laser scanning microscopy, field emission scanning electron microscopy and transmission electron microscopy. The results revealed that a low dose (13 microg ml(-1)) of PHMG slightly damaged the outer membrane structure of the treated bacteria and increased the permeability of the cytoplasmic membrane, while no significant damage was observed to the morphological structure of the cells. A high dose (23 microg ml(-1)) of PHMG collapsed the outer membrane structure, led to the formation of a local membrane pore across the membrane and badly damaged the internal structure of the cells. Subsequently, intracellular components were leaked followed by cell inactivation. Dose-dependent membrane disruption was the main bactericidal mechanism of PHMG. The formation of the local membrane pores was probable after exposure to a high dose (23 microg ml(-1)) of PHMG. Micrographic evidences were provided about the damaged membrane structure and intracellular structure change of E. coli. The presented information helps understand the bactericidal mechanism of PHMG by membrane damage.

Bactericidal activity of herbal volatile oil extracts against multidrug-resistant Acinetobacter baumannii.

PubMed

Intorasoot, Amornrat; Chornchoem, Piyaorn; Sookkhee, Siriwoot; Intorasoot, Sorasak

2017-01-01

The aim of the study is to investigate the antibacterial activity of 10 volatile oils extracted from medicinal plants, including galangal ( Alpinia galanga Linn.), ginger ( Zingiber officinale ), plai ( Zingiber cassumunar Roxb.), lime ( Citrus aurantifolia ), kaffir lime ( Citrus hystrix DC.), sweet basil ( Ocimum basilicum Linn.), tree basil ( Ocimum gratissimum ), lemongrass ( Cymbopogon citratus DC.), clove ( Syzygium aromaticum ), and cinnamon ( Cinnamomum verum ) against four standard strains of Staphylococcus aureus , Escherichia coli , Pseudomonas aeruginosa , Acinetobacter baumannii , and 30 clinical isolates of multidrug-resistant A. baumannii (MDR- A. baumannii ). Agar diffusion, minimum inhibitory concentration, and minimum bactericidal concentration (MBC) were employed for the determination of bactericidal activity of water distilled medicinal plants. Tea tree oil ( Melaleuca alternifolia ) was used as positive control in this study. The results indicated the volatile oil extracted from cinnamon exhibited potent antibacterial activity against the most common human pathogens, S. aureus , E. coli , P. aeruginosa , and A. baumannii . Most of volatile oil extracts were less effective against non-fermentative bacteria, P. aeruginosa . In addition, volatile oil extracted from cinnamon, clove, and tree basil possessed potent bactericidal activity against MDR- A. baumannii with MBC 90 of 0.5, 1, and 2 mg/mL, respectively. The volatile oil extracts would be useful as alternative natural product for the treatment of the most common human pathogens and MDR- A. baumannii infections.

Green synthesis and characterization of Carica papaya leaf extract coated silver nanoparticles through X-ray diffraction, electron microscopy and evaluation of bactericidal properties

PubMed Central

Banala, Rajkiran Reddy; Nagati, Veera Babu; Karnati, Pratap Reddy

2015-01-01

The evolution of nanotechnology and the production of nanomedicine from various sources had proven to be of intense value in the field of biomedicine. The smaller size of nanoparticles is gaining importance in research for the treatment of various diseases. Moreover the production of nanoparticles is eco-friendly and cost effective. In the present study silver nanoparticles were synthesized from Carica papaya leaf extract (CPL) and characterized for their size and shape using scanning electron microscopy and transmission electron microscopy, respectively. Fourier transform infrared spectroscopy (FTIR), Energy dispersive X-ray spectroscopy (EDS/EDX) and X-ray diffraction spectroscopy (XRD) were conducted to determine the concentration of metal ions, the shape of molecules. The bactericidal activity was evaluated using Luria Bertani broth cultures and the minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) were estimated using turbidimetry. The data analysis showed size of 50–250 nm spherical shaped nanoparticles. The turbidimetry analysis showed MIC and MBC was >25 μg/mL against both Gram positive and Gram negative bacteria in Luria Bertani broth cultures. In summary the synthesized silver nanoparticles from CPL showed acceptable size and shape of nanoparticles and effective bactericidal activity. PMID:26288570

Green synthesis and characterization of Carica papaya leaf extract coated silver nanoparticles through X-ray diffraction, electron microscopy and evaluation of bactericidal properties.

PubMed

Banala, Rajkiran Reddy; Nagati, Veera Babu; Karnati, Pratap Reddy

2015-09-01

The evolution of nanotechnology and the production of nanomedicine from various sources had proven to be of intense value in the field of biomedicine. The smaller size of nanoparticles is gaining importance in research for the treatment of various diseases. Moreover the production of nanoparticles is eco-friendly and cost effective. In the present study silver nanoparticles were synthesized from Carica papaya leaf extract (CPL) and characterized for their size and shape using scanning electron microscopy and transmission electron microscopy, respectively. Fourier transform infrared spectroscopy (FTIR), Energy dispersive X-ray spectroscopy (EDS/EDX) and X-ray diffraction spectroscopy (XRD) were conducted to determine the concentration of metal ions, the shape of molecules. The bactericidal activity was evaluated using Luria Bertani broth cultures and the minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) were estimated using turbidimetry. The data analysis showed size of 50-250 nm spherical shaped nanoparticles. The turbidimetry analysis showed MIC and MBC was >25 μg/mL against both Gram positive and Gram negative bacteria in Luria Bertani broth cultures. In summary the synthesized silver nanoparticles from CPL showed acceptable size and shape of nanoparticles and effective bactericidal activity.

An investigation of the bactericidal activity of chlorhexidine digluconateagainst multidrug-resistant hospital isolates.

PubMed

Ekizoğlu, Melike; Sağiroğlu, Meral; Kiliç, Ekrem; Hasçelik, Ayşe Gülşen

2016-04-19

Hospital infections are among the most prominent medical problems around the world. Using proper biocides in an appropriate way is critically important in overcoming this problem. Several reports have suggested that microorganisms may develop resistance or reduce their susceptibility to biocides, similar to the case with antibiotics. In this study we aimed to determine the antimicrobial activity of chlorhexidine digluconate against clinical isolates. The susceptibility of 120 hospital isolated strains of 7 bacterial genera against chlorhexidine digluconate was determined by agar dilution test, using minimum inhibitory concentration (MIC) values and the EN 1040 Basic Bactericidal Activity Test to determine the bactericidal activity. According to MIC values, Pseudomonas aeruginosa and Stenotrophomonas maltophilia were found to be less susceptible to chlorhexidine digluconate. Quantitative suspension test results showed that 4% chlorhexidine digluconate was effective against antibiotic resistant and susceptible bacteria after 5 min of contact time and can be safely used in our hospital. However, concentrations below 4% chlorhexidine digluconate caused a decrease in bactericidal activity, especially for Staphylococcus aureus and P. aeruginosa. It is crucial to use biocides at appropriate concentrations and to perform surveillance studies to trace resistance or low susceptibility patterns of S. aureus, P. aeruginosa, and other hospital isolates.

Inhibition of intracellular bacterial replication in fibroblasts is dependent on the perforin-like protein (Perforin-2) encoded by macrophage expressed gene 1

PubMed Central

McCormack, Ryan; de Armas, Lesley R.; Shiratsuchi, Motoaki; Ramos, Jay; Podack, Eckhard R.

2013-01-01

Fibroblasts are known to eliminate intracellular bacteria, but the lethal hit of the bactericidal mechanism has not been defined. We show that primary embryonic and established fibroblasts can be induced by interferons or by intracellular bacterial infection to express a perforin-like mRNA previously described as macrophage expressed gene 1 (mpeg1). The presence and level of the perforin-like mRNA correlate with the ability of primary mouse embryonic fibroblasts (MEF) to eliminate intracellular bacteria. In addition, siRNA knock-down of the perforin-like molecule abolishes bactericidal activity and allows intracellular bacterial replication. Complementation of MEF in which the endogenous perforin-like molecule has been knocked down with an RFP-tagged version restores bactericidal activity. The perforin-like molecule has broad bactericidal specificity for pathogenic and non-pathogenic bacteria including Gram positive, Gram negative and acid fast bacteria. The perforin-like molecule renders previously lysozyme-resistant bacteria sensitive to lysis by lysozyme suggesting physical damage of the outer cell wall by the perforin-like protein. MEFs damage cell walls of intracellular bacteria by insertion, polymerization and pore-formation of the perforin-like protein, analogous to pore-formers of complement and Perforin-1 of cytolytic lymphocytes. We propose the name Perforin-2. PMID:23257510

Colloidal metal oxide nanoparticle systems: the new promising way to prevent antibiotic resistance during treatment of local infectious processes

NASA Astrophysics Data System (ADS)

Karasenkov, Y.; Frolov, G.; Pogorelsky, I.; Latuta, N.; Gusev, A.; Kuznetsov, D.; Leont'ev, V.

2015-11-01

New bactericidal containing nanoparticles colloids for application in dentistry, maxillofacial surgery, urology, obstetrics, gynaecology, ENT, proctology have been developed. The various water colloidal nanodispersive systems of metals and oxides have been obtained by means of electric impulse - condensation (electroerosion) method. These systems are based pure elements and alloys of argentum (Ag), titanium dioxide (TiO2), iron oxide (Fe2O3), tantalum oxide (TaO), vanadium oxide (VO2), cobalt oxide (CoO), tantalum dioxide TaO2, zinc oxide (ZnO), copper oxide (CuO) and mixed suspensions of titanium, aluminium and molybdenum oxides. The research has been made on culture of dentobacterial plaque and mixed culture issued from gingival spaces. The composition of culture was identified with S.aureus, S.epidermidis and nonfermentable kinds of E.coli. The observation period lasted more than nineteen days. All solutions showed highly prolonged bactericidal activity in dilutions from the whole solution 1-20 mg/L. The bactericidal activity of powder specimen of silica containing Ag and Fe2O3 nanoparticles used as dental filling material and disintegrates of composite materials (produced by “StomaDent” CJSC) have been studied. Tested materials have long (up to 19 days and more) bactericidal activity.

Bactericidal activity of electrolyzed acid water from solution containing sodium chloride at low concentration, in comparison with that at high concentration.

PubMed

Kiura, Hiromasa; Sano, Kouichi; Morimatsu, Shinichi; Nakano, Takashi; Morita, Chizuko; Yamaguchi, Masaki; Maeda, Toyoyuki; Katsuoka, Yoji

2002-05-01

Electrolyzed strong acid water (ESW) containing free chlorine at various concentrations is becoming to be available in clinical settings as a disinfectant. ESW is prepared by electrolysis of a NaCl solution, and has a corrosive activity against medical instruments. Although lower concentrations of NaCl and free chlorine are desired to eliminate corrosion, the germicidal effect of ESW with low NaCl and free-chlorine concentrations (ESW-L) has not been fully clarified. In this study, we demonstrated that ESW-L possesses bactericidal activity against Mycobacteria and spores of Bacillus subtilis. The effect was slightly weaker than that of ESW containing higher NaCl and free-chlorine concentrations (ESW-H), but acceptable as a disinfectant. To clarify the mechanism of the bactericidal activity, we investigated ESW-L-treated Pseudomonas aeruginosa by transmission electron microscopy, a bacterial enzyme assay and restriction fragment length polymorphism pattern (RFLP) assay. Since the bacterium, whose growth was completely inhibited by ESW-L, revealed the inactivation of cytoplasmic enzyme, blebs and breaks in its outer membrane and remained complete RFLP of DNA, damage of the outer membrane and inactivation of cytoplasmic enzyme are the important determinants of the bactericidal activity.