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Sample records for actively infected cells

  1. MAIT cells are activated during human viral infections.

    PubMed

    van Wilgenburg, Bonnie; Scherwitzl, Iris; Hutchinson, Edward C; Leng, Tianqi; Kurioka, Ayako; Kulicke, Corinna; de Lara, Catherine; Cole, Suzanne; Vasanawathana, Sirijitt; Limpitikul, Wannee; Malasit, Prida; Young, Duncan; Denney, Laura; Moore, Michael D; Fabris, Paolo; Giordani, Maria Teresa; Oo, Ye Htun; Laidlaw, Stephen M; Dustin, Lynn B; Ho, Ling-Pei; Thompson, Fiona M; Ramamurthy, Narayan; Mongkolsapaya, Juthathip; Willberg, Christian B; Screaton, Gavin R; Klenerman, Paul

    2016-01-01

    Mucosal-associated invariant T (MAIT) cells are abundant in humans and recognize bacterial ligands. Here, we demonstrate that MAIT cells are also activated during human viral infections in vivo. MAIT cells activation was observed during infection with dengue virus, hepatitis C virus and influenza virus. This activation-driving cytokine release and Granzyme B upregulation-is TCR-independent but dependent on IL-18 in synergy with IL-12, IL-15 and/or interferon-α/β. IL-18 levels and MAIT cell activation correlate with disease severity in acute dengue infection. Furthermore, HCV treatment with interferon-α leads to specific MAIT cell activation in vivo in parallel with an enhanced therapeutic response. Moreover, TCR-independent activation of MAIT cells leads to a reduction of HCV replication in vitro mediated by IFN-γ. Together these data demonstrate MAIT cells are activated following viral infections, and suggest a potential role in both host defence and immunopathology. PMID:27337592

  2. MAIT cells are activated during human viral infections

    PubMed Central

    van Wilgenburg, Bonnie; Scherwitzl, Iris; Hutchinson, Edward C.; Leng, Tianqi; Kurioka, Ayako; Kulicke, Corinna; de Lara, Catherine; Cole, Suzanne; Vasanawathana, Sirijitt; Limpitikul, Wannee; Malasit, Prida; Young, Duncan; Denney, Laura; Barnes, Eleanor; Ball, Jonathan; Burgess, Gary; Cooke, Graham; Dillon, John; Gore, Charles; Foster, Graham; Guha, Neil; Halford, Rachel; Herath, Cham; Holmes, Chris; Howe, Anita; Hudson, Emma; Irving, William; Khakoo, Salim; Koletzki, Diana; Martin, Natasha; Mbisa, Tamyo; McKeating, Jane; McLauchlan, John; Miners, Alec; Murray, Andrea; Shaw, Peter; Simmonds, Peter; Spencer, Chris; Targett-Adams, Paul; Thomson, Emma; Vickerman, Peter; Zitzmann, Nicole; Moore, Michael D.; Fabris, Paolo; Giordani, Maria Teresa; Oo, Ye Htun; Laidlaw, Stephen M.; Dustin, Lynn B.; Ho, Ling-Pei; Thompson, Fiona M.; Ramamurthy, Narayan; Mongkolsapaya, Juthathip; Willberg, Christian B.; Screaton, Gavin R.; Klenerman, Paul

    2016-01-01

    Mucosal-associated invariant T (MAIT) cells are abundant in humans and recognize bacterial ligands. Here, we demonstrate that MAIT cells are also activated during human viral infections in vivo. MAIT cells activation was observed during infection with dengue virus, hepatitis C virus and influenza virus. This activation—driving cytokine release and Granzyme B upregulation—is TCR-independent but dependent on IL-18 in synergy with IL-12, IL-15 and/or interferon-α/β. IL-18 levels and MAIT cell activation correlate with disease severity in acute dengue infection. Furthermore, HCV treatment with interferon-α leads to specific MAIT cell activation in vivo in parallel with an enhanced therapeutic response. Moreover, TCR-independent activation of MAIT cells leads to a reduction of HCV replication in vitro mediated by IFN-γ. Together these data demonstrate MAIT cells are activated following viral infections, and suggest a potential role in both host defence and immunopathology. PMID:27337592

  3. Activation of Complement by Cells Infected with Respiratory Syncytial Virus

    PubMed Central

    Smith, Thomas F.; Mcintosh, Kenneth; Fishaut, Mark; Henson, Peter M.

    1981-01-01

    The ability of respiratory syncytial virus (RSV)-infected HEp-2 cells in culture to activate complement was investigated. After incubation of cells with various complement sources and buffer, binding of C3b to surfaces of infected cells was demonstrated by immunofluorescence with a double-staining technique. Nonsyncytial and syncytial (i.e., fused, multinucleated) cells were separately enumerated. Also, lysis of RSV-infected cells was assessed by lactic dehydrogenase release. In this system only RSV-infected cells stained for C3b, and they did so only after incubation with functionally active complement. Blocking of classical pathway activation with ethylenediaminetetraacetic acid diminished the number of infected nonsyncytial cells positively stained for C3b, but had no effect on staining of syncytial cells. Blocking of alternative pathway activation with either zymosan incubation or heat treatment decreased the number of both syncytial and nonsyncytial cells stained for C3b. Decreasing immunoglobulin concentration of the serum used as the complement source also decreased numbers of both cell types stained for C3b. Eliminating specific anti-RSV antibody diminished numbers of both cell types stained for C3b, but staining was not eliminated. Lastly, incubation with functionally active complement markedly increased lactic dehydrogenase release from infected cells. This study demonstrated that RSV-infected nonsyncytial and syncytial cells are able to activate complement by both classical and alternative pathways. Activation of complement by syncytial cells appears to be less dependent on the classical pathway than is activation by nonsyncytial cells, and activation by syncytial cells may require immunoglobulin but not specific antibody. These experiments suggest the possibility of complement activation during respiratory tract infection by RSV. Implications of this are discussed. Images PMID:7263071

  4. Dengue Virus Infection of Mast Cells Triggers Endothelial Cell Activation

    PubMed Central

    Brown, Michael G.; Hermann, Laura L.; Issekutz, Andrew C.; Marshall, Jean S.; Rowter, Derek; Al-Afif, Ayham; Anderson, Robert

    2011-01-01

    Vascular perturbation is a hallmark of severe forms of dengue disease. We show here that antibody-enhanced dengue virus infection of primary human cord blood-derived mast cells (CBMCs) and the human mast cell-like line HMC-1 results in the release of factor(s) which activate human endothelial cells, as evidenced by increased expression of the adhesion molecules ICAM-1 and VCAM-1. Endothelial cell activation was prevented by pretreatment of mast cell-derived supernatants with a tumor necrosis factor (TNF)-specific blocking antibody, thus identifying TNF as the endothelial cell-activating factor. Our findings suggest that mast cells may represent an important source of TNF, promoting vascular endothelial perturbation following antibody-enhanced dengue virus infection. PMID:21068256

  5. Bacterial Manipulation of NK Cell Regulatory Activity Increases Susceptibility to Listeria monocytogenes Infection

    PubMed Central

    Guthrie, Brandon S.; Schmidt, Rebecca L.; Jamieson, Amanda; Merkel, Patricia; Knight, Vijaya; Cole, Caroline M.; Raulet, David H.; Lenz, Laurel L.

    2016-01-01

    Natural killer (NK) cells produce interferon (IFN)-γ and thus have been suggested to promote type I immunity during bacterial infections. Yet, Listeria monocytogenes (Lm) and some other pathogens encode proteins that cause increased NK cell activation. Here, we show that stimulation of NK cell activation increases susceptibility during Lm infection despite and independent from robust NK cell production of IFNγ. The increased susceptibility correlated with IL-10 production by responding NK cells. NK cells produced IL-10 as their IFNγ production waned and the Lm virulence protein p60 promoted induction of IL-10 production by mouse and human NK cells. NK cells consequently exerted regulatory effects to suppress accumulation and activation of inflammatory myeloid cells. Our results reveal new dimensions of the role played by NK cells during Lm infection and demonstrate the ability of this bacterial pathogen to exploit the induction of regulatory NK cell activity to increase host susceptibility. PMID:27295349

  6. Neutrophil cell death, activation and bacterial infection in cystic fibrosis

    PubMed Central

    Watt, A; Courtney, J; Moore, J; Ennis, M; Elborn, J

    2005-01-01

    Background: Cystic fibrosis (CF) is characterised by chronic endobronchial bacterial infection and neutrophil mediated inflammation. Neutrophil apoptosis is essential for the resolution of inflammation. This study assessed the relationship between levels of neutrophil apoptosis and sputum microbiology in matched clinically stable patients with CF. Methods: Sputum was induced from 34 patients (nine with no Gram negative infection, 10 colonised with Pseudomonas aeruginosa, 10 with Burkholderia cenocepacia, and five with other infections). Apoptotic neutrophils measured by flow cytometric Annexin V/propidium iodide staining and morphology were similar in all groups. Results: Patients infected with P aeruginosa or B cenocepacia had a significantly lower percentage of viable neutrophils in the sputum than those with no Gram negative infection (Kruskal-Wallis p = 0.01, median (interquartile range (IQR)) 14.2% (9.4–21.6), 15.8% (12.3–19.5), and 48.4% (23.0–66.4); p = 0.003 and p = 0.002, respectively). They also had significantly higher levels of secondary necrotic granulocytes in sputum than patients with no Gram negative infection (Kruskal-Wallis p<0.0001, median (IQR) 55.5% (48.4–64.5), 50.4% (44.6–61.9), and 24.8% (14.4–30.5); p<0.0001 and p<0.0001, respectively). Neutrophils (x106/g sputum) in P aeruginosa infected patients (Kruskal-Wallis p = 0.05, median (IQR) 6.3 (3.5–12.7)) and B cenocepacia infected patients (5.7 (1.5–14.5)) were significantly higher than in the group with no Gram negative infection (0.5 (0.5–4.3), p = 0.03 and 0.04, respectively). Conclusion: These results suggest that cell death and clearance may be altered in patients with CF colonised with P aeruginosa and B cenocepacia compared with those with no Gram negative infection. PMID:16061707

  7. Effects of immunomodulators on functional activity of innate immunity cells infected with Streptococcus pneumoniae.

    PubMed

    Plekhova, N G; Kondrashova, N M; Somova, L M; Drobot, E I; Lyapun, I N

    2015-02-01

    Low activity of bactericidal enzymes was found in innate immunity cells infected with S. pneumonia. The death of these cells was fastened under these conditions. On the contrary, treatment with antibiotic maxifloxacin was followed by an increase in activity of bactericidal enzymes in phagocytes and induced their death via necrosis. Analysis of the therapeutic properties of immunomodulators tinrostim and licopid in combination with maxifloxacin showed that these combinations correct functional activity of cells infected with S. pneumonia. PMID:25708326

  8. Autoimmunity, polyclonal B-cell activation and infection.

    PubMed

    Granholm, N A; Cavallo, T

    1992-02-01

    It is widely believed that autoimmunity is an integral part of the immune system, and that genetic, immunologic, hormonal, environmental and other factors contribute to the pathogenesis of autoimmune disease. Thus, autoimmune disease may represent an abnormal expression of immune functions instead of loss of tolerance to self, and it can be organ specific or systemic in its manifestations. We review the various factors that contribute to the development of autoimmune disease; we also review the mechanisms of polyclonal B-cell activation, with emphasis on the role of infectious agents. We consider systemic lupus erythematosus in humans and in experimental animals as prototypic autoimmune disease, and we summarize data to indicate that polyclonal B-cell activation is central to the pathogenesis of systemic autoimmune disease. The effect of polyclonal B-cell activation, brought about by injections of a B-cell activator-lipopolysaccharide from Gram-negative bacteria-is sufficient to cause autoimmune disease in an immunologically normal host. In fact, autoimmune disease can be arrested if excessive polyclonal B-cell activation is suppressed; alternatively, autoimmune disease can be exacerbated if polyclonal B-cell activation is enhanced. We explore the mechanism of tissue injury when autoimmune disease is induced or exacerbated, and we consider the pathogenic roles of autoantibodies, immune complexes, complement, the blood cell carrier system, and the mononuclear phagocyte system. Although polyclonal B-cell activation may be the mechanism whereby various factors can cause or exacerbate systemic autoimmune disease, polyclonal B-cell activation may cause autoimmune disease on its own.

  9. CD4 T cell activation by B cells in human Leishmania (Viannia) infection

    PubMed Central

    2014-01-01

    activate CD4 T cells and induce cytokine secretion is similar to that of all cell populations present in PBMCs. This capacity implicates B cells as a plausible target for modulation of the immune response to Leishmania infection as a therapeutic strategy. PMID:24568275

  10. Accumulation and activation of natural killer cells in local intraperitoneal HIV-1/MuLV infection results in early control of virus infected cells.

    PubMed

    Johansson, Susanne E; Brauner, Hanna; Hinkula, Jorma; Wahren, Britta; Berg, Louise; Johansson, Maria H

    2011-01-01

    Natural killer (NK) cells are important effectors in resistance to viral infections. The role of NK cells in the acute response to human immunodeficiency virus 1 (HIV-1) infected cells was investigated in a mouse model based on a HIV-1/murine leukemia virus (MuLV) pseudovirus. Splenocytes infected with HIV-1/MuLV were injected intraperitoneally and local immunologic responses and persistence of infected cells were investigated. In vivo depletion with an anti-NK1.1 antibody showed that NK cells are important in resistance to virus infected cells. Moreover, NK cell frequency in the peritoneal cavity increased in response to infected cells and these NK cells had a more mature phenotype, as determined by CD27 and Mac-1 expression. Interestingly, after injection of HIV-1/MuLV infected cells, but not MuLV infected cells, peritoneal NK cells had an increased cytotoxic activity. In conclusion, NK cells play a role in the early control of HIV-1/MuLV infected cells in vivo.

  11. Distinct activation of primary human BDCA1(+) dendritic cells upon interaction with stressed or infected β cells.

    PubMed

    Schulte, B M; Kers-Rebel, E D; Bottino, R; Piganelli, J D; Galama, J M D; Engelse, M A; de Koning, E J P; Adema, G J

    2016-06-01

    Derailment of immune responses can lead to autoimmune type 1 diabetes, and this can be accelerated or even induced by local stress caused by inflammation or infection. Dendritic cells (DCs) shape both innate and adaptive immune responses. Here, we report on the responses of naturally occurring human myeloid BDCA1(+) DCs towards differentially stressed pancreatic β cells. Our data show that BDCA1(+) DCs in human pancreas-draining lymph node (pdLN) suspensions and blood-derived BDCA1(+) DCs both effectively engulf β cells, thus mimicking physiological conditions. Upon uptake of enterovirus-infected, but not mock-infected cells, BDCA1(+) DCs induced interferon (IFN)-α/β responses, co-stimulatory molecules and proinflammatory cytokines and chemokines. Notably, induction of stress in β cells by ultraviolet irradiation, culture in serum-free medium or cytokine-induced stress did not provoke strong DC activation, despite efficient phagocytosis. DC activation correlated with the amount of virus used to infect β cells and required RNA within virally infected cells. DCs encountering enterovirus-infected β cells, but not those incubated with mock-infected or stressed β cells, suppressed T helper type 2 (Th2) cytokines and variably induced IFN-γ in allogeneic mixed lymphocyte reaction (MLR). Thus, stressed β cells have little effect on human BDCA1(+) DC activation and function, while enterovirus-infected β cells impact these cells significantly, which could help to explain their role in development of autoimmune diabetes in individuals at risk.

  12. Tetherin/BST-2 promotes dendritic cell activation and function during acute retrovirus infection

    PubMed Central

    Li, Sam X.; Barrett, Bradley S.; Guo, Kejun; Kassiotis, George; Hasenkrug, Kim J.; Dittmer, Ulf; Gibbert, Kathrin; Santiago, Mario L.

    2016-01-01

    Tetherin/BST-2 is a host restriction factor that inhibits retrovirus release from infected cells in vitro by tethering nascent virions to the plasma membrane. However, contradictory data exists on whether Tetherin inhibits acute retrovirus infection in vivo. Previously, we reported that Tetherin-mediated inhibition of Friend retrovirus (FV) replication at 2 weeks post-infection correlated with stronger natural killer, CD4+ T and CD8+ T cell responses. Here, we further investigated the role of Tetherin in counteracting retrovirus replication in vivo. FV infection levels were similar between wild-type (WT) and Tetherin KO mice at 3 to 7 days post-infection despite removal of a potent restriction factor, Apobec3/Rfv3. However, during this phase of acute infection, Tetherin enhanced myeloid dendritic cell (DC) function. DCs from infected, but not uninfected, WT mice expressed significantly higher MHC class II and the co-stimulatory molecule CD80 compared to Tetherin KO DCs. Tetherin-associated DC activation during acute FV infection correlated with stronger NK cell responses. Furthermore, Tetherin+ DCs from FV-infected mice more strongly stimulated FV-specific CD4+ T cells ex vivo compared to Tetherin KO DCs. The results link the antiretroviral and immunomodulatory activity of Tetherin in vivo to improved DC activation and MHC class II antigen presentation. PMID:26846717

  13. Activation of small ruminant aortic endothelial cells after in vitro infection by caprine arthritis encephalitis virus.

    PubMed

    Jan, C L; Greenland, T; Gounel, F; Balleydier, S; Mornex, J F

    2000-12-01

    Small ruminants infected by the lentiviruses caprine arthritis-encephalitis virus (CAEV), originally isolated from a goat, or maedi-visna virus, originally from sheep, typically develop an organising lymphoid infiltration of affected tissues. This could reflect modulation of the migration pattern of lymphocytes in infected animals. Possible active contribution by vascular endothelial cells was investigated using an in vitro model. Low-passage cultured ovine aortic endothelium proved susceptible to productive infection by CAEV without significant cytotoxicity. Infected endothelial cells maintained expression of endothelial markers, increased MHC class I antigen expression and initiated expression of the adhesion molecule VCAM -1 and, at a late stage, MHC class II antigens. Infected endothelial cells showed a two-fold increase in binding capacity for sheep peripheral blood leucocytes over uninfected controls. Such events could contribute to the tissue distribution of lymphoid cells and local immune responses in lentiviral infections of small ruminants. PMID:11124093

  14. Activated natural killer cells accelerate liver damage in patients with chronic hepatitis B virus infection.

    PubMed

    Zheng, Q; Zhu, Y Y; Chen, J; Ye, Y B; Li, J Y; Liu, Y R; Hu, M L; Zheng, Y C; Jiang, J J

    2015-06-01

    Emerging evidence indicates that natural killer (NK) cells may contribute to liver injury in patients with hepatitis B virus (HBV) infection. Because HBV infection progresses through various disease phases, the cytolytic profiles of peripheral and intrahepatic NK cells in HBV-infected patients remain to be defined. In this study, we comprehensively characterized intrahepatic and peripheral NK cells in a cohort of HBV-infected individuals, and investigated their impact on liver pathogenesis during chronic HBV infection. The study population included 34 immune-clearance (IC) patients, 36 immune-tolerant (IT) carriers and 10 healthy subjects. We found that the activity of peripheral NK cells from IC patients was functionally elevated compared to IT carriers and controls, and NK cell activation was indicated by an increased expression of CD69, CD107a, interferon (IFN)-γ and tumour necrosis factor (TNF)-α. Further analysis showed that the increased activity of both peripheral and hepatic NK cells was correlated positively with liver injury, which was assessed by serum alanine aminotransferase levels (ALT) and the liver histological activity index (HAI). Interestingly, the frequency of peripheral NK cells was reduced in IC patients (especially those with higher HAI scores of 3-4), but there was a concomitant increase in hepatic NK cells. The functionally activated NK cells are enriched preferentially in the livers of IC patients and skew towards cytolytic activity that accelerates liver injury in chronic hepatitis B (CHB) patients.

  15. IL-15 promotes activation and expansion of CD8+ T cells in HIV-1 infection

    PubMed Central

    Younes, Souheil-Antoine; Freeman, Michael L.; Mudd, Joseph C.; Shive, Carey L.; Reynaldi, Arnold; Estes, Jacob D.; Deleage, Claire; Lucero, Carissa; Anderson, Jodi; Schacker, Timothy W.; Davenport, Miles P.; McCune, Joseph M.; Hunt, Peter W.; Lee, Sulggi A.; Debernardo, Robert L.; Jacobson, Jeffrey M.; Canaday, David H.; Sekaly, Rafick-Pierre; Sieg, Scott F.; Lederman, Michael M.

    2016-01-01

    In HIV-1–infected patients, increased numbers of circulating CD8+ T cells are linked to increased risk of morbidity and mortality. Here, we identified a bystander mechanism that promotes CD8 T cell activation and expansion in untreated HIV-1–infected patients. Compared with healthy controls, untreated HIV-1–infected patients have an increased population of proliferating, granzyme B+, CD8+ T cells in circulation. Vβ expression and deep sequencing of CDR3 revealed that in untreated HIV-1 infection, cycling memory CD8 T cells possess a broad T cell repertoire that reflects the repertoire of the resting population. This suggests that cycling is driven by bystander activation, rather than specific antigen exposure. Treatment of peripheral blood mononuclear cells with IL-15 induced a cycling, granzyme B+ phenotype in CD8+ T cells. Moreover, elevated IL-15 expression in the lymph nodes of untreated HIV-1–infected patients correlated with circulating CD8+ T cell counts and was normalized in these patients following antiretroviral therapy. Together, these results suggest that IL-15 drives bystander activation of CD8+ T cells, which predicts disease progression in untreated HIV-1–infected patients and suggests that elevated IL-15 may also drive CD8+ T cell expansion that is linked to increased morbidity and mortality in treated patients. PMID:27322062

  16. Macrophage Activation Redirects Yersinia-Infected Host Cell Death from Apoptosis to Caspase-1-Dependent Pyroptosis

    PubMed Central

    Bergsbaken, Tessa; Cookson, Brad T

    2007-01-01

    Infection of macrophages by Yersinia species results in YopJ-dependent apoptosis, and naïve macrophages are highly susceptible to this form of cell death. Previous studies have demonstrated that macrophages activated with lipopolysaccharide (LPS) prior to infection are resistant to YopJ-dependent cell death; we found this simultaneously renders macrophages susceptible to killing by YopJ− Yersinia pseudotuberculosis (Yptb). YopJ− Yptb-induced macrophage death was dependent on caspase-1 activation, resulting in rapid permeability to small molecules, followed by membrane breakdown and DNA damage, and accompanied by cleavage and release of proinflammatory interleukin-18. Induction of caspase-1-dependent death, or pyroptosis, required the bacterial type III translocon but none of its known translocated proteins. Wild-type Yptb infection also triggered pyroptosis: YopJ-dependent activation of proapoptotic caspase-3 was significantly delayed in activated macrophages and resulted in caspase-1-dependent pyroptosis. The transition to susceptibility was not limited to LPS activation; it was also seen in macrophages activated with other Toll-like receptor (TLR) ligands and intact nonviable bacteria. Yptb infection triggered macrophage activation and activation of caspase-1 in vivo. Y. pestis infection of activated macrophages also stimulated caspase-1 activation. These results indicate that host signaling triggered by TLR and other activating ligands during the course of Yersinia infection redirects both the mechanism of host cell death and the downstream consequences of death by shifting from noninflammatory apoptosis to inflammatory pyroptosis. PMID:17983266

  17. Cell death, BAX activation, and HMGB1 release during infection with Chlamydia.

    PubMed

    Jungas, Thomas; Verbeke, Philippe; Darville, Toni; Ojcius, David M

    2004-11-01

    Infection by a number of Chlamydia species leads to resistance of the host cell to apoptosis, followed by induction of host-cell death. In a population of infected cells that displays protection against staurosporine-induced apoptosis among the adherent cells, we find that cells that had been recovered from the supernatant share characteristics of both apoptosis and necrosis, as assayed by the propidium iodide (PI)-annexin V double-labeling technique. Cell death was observed in both an epithelial cell line and primary fibroblasts, although the primary cells had a higher propensity to die through apoptosis than the immortalized cell line. Staurosporine-mediated activation of the pro-apoptotic BCL-2 family member, BAX, was inhibited in the epithelial cell line infected for 32 h with the lymphogranuloma venereum (LGV/L2) but not the murine pneumonitis (MoPn) strain of C. trachomatis, but inhibition of staurosporine-mediated BAX activation disappeared after 48 h of infection with the LGV/L2 strain. Conversely, infection with MoPn (C. muridarum) but not LGV/L2 led to BAX activation after 72 h, as previously reported for shorter (48 h) infection with the guinea pig inclusion conjunctivitis (GPIC) serovar of C. psittaci (C. caviae). These results suggest that the ability to inhibit staurosporine-mediated BAX activation or to activate BAX due to the infection itself may vary as a function of the chlamydial strain. Interestingly, both the epithelial cells and the fibroblasts also released high mobility group box 1 protein (HMGB1) during infection, although much less HMGB1 was released from fibroblasts, consistent with the higher level of apoptosis observed in the primary cells. HMGB1 is released preferentially by necrotic or permeabilized viable cells, but not apoptotic cells. In the extracellular space, HMGB1 promotes inflammation through interaction with specific cell-surface receptors. Higher levels of HMGB1 were also measured in the genital-tract secretions of mice

  18. EV71-infected CD14(+) cells modulate the immune activity of T lymphocytes in rhesus monkeys.

    PubMed

    Wang, Jingjing; Pu, Jing; Huang, Hongtai; Zhang, Ying; Liu, Longding; Yang, Erxia; Zhou, Xiaofang; Ma, Na; Zhao, Hongling; Wang, Lichun; Xie, Zhenfeng; Tang, Donghong; Li, Qihan

    2013-07-01

    Preliminary studies of the major pathogen enterovirus 71 (EV71), a member of the Picornaviridae family, have suggested that EV71 may be a major cause of fatal hand, foot and mouth disease cases. Currently, the role of the pathological changes induced by EV71 infection in the immunopathogenic response remains unclear. Our study focused on the interaction between this virus and immunocytes and indicated that this virus has the ability to replicate in CD14(+) cells. Furthermore, these EV71-infected CD14(+) cells have the capacity to stimulate the proliferation of T cells and to enhance the release of certain functional cytokines. An adaptive immune response induced by the back-transfusion of EV71-infected CD14(+) cells was observed in donor neonatal rhesus monkeys. Based on these observations, the proposed hypothesis is that CD14(+) cells infected by the EV71 virus might modulate the anti-EV71 adaptive immune response by inducing simultaneous T-cell activation.

  19. Exosomes Derived from HIV-1-infected Cells Contain Trans-activation Response Element RNA*

    PubMed Central

    Narayanan, Aarthi; Iordanskiy, Sergey; Das, Ravi; Van Duyne, Rachel; Santos, Steven; Jaworski, Elizabeth; Guendel, Irene; Sampey, Gavin; Dalby, Elizabeth; Iglesias-Ussel, Maria; Popratiloff, Anastas; Hakami, Ramin; Kehn-Hall, Kylene; Young, Mary; Subra, Caroline; Gilbert, Caroline; Bailey, Charles; Romerio, Fabio; Kashanchi, Fatah

    2013-01-01

    Exosomes are nano-sized vesicles produced by healthy and virus-infected cells. Exosomes derived from infected cells have been shown to contain viral microRNAs (miRNAs). HIV-1 encodes its own miRNAs that regulate viral and host gene expression. The most abundant HIV-1-derived miRNA, first reported by us and later by others using deep sequencing, is the trans-activation response element (TAR) miRNA. In this study, we demonstrate the presence of TAR RNA in exosomes from cell culture supernatants of HIV-1-infected cells and patient sera. TAR miRNA was not in Ago2 complexes outside the exosomes but enclosed within the exosomes. We detected the host miRNA machinery proteins Dicer and Drosha in exosomes from infected cells. We report that transport of TAR RNA from the nucleus into exosomes is a CRM1 (chromosome region maintenance 1)-dependent active process. Prior exposure of naive cells to exosomes from infected cells increased susceptibility of the recipient cells to HIV-1 infection. Exosomal TAR RNA down-regulated apoptosis by lowering Bim and Cdk9 proteins in recipient cells. We found 104–106 copies/ml TAR RNA in exosomes derived from infected culture supernatants and 103 copies/ml TAR RNA in the serum exosomes of highly active antiretroviral therapy-treated patients or long term nonprogressors. Taken together, our experiments demonstrated that HIV-1-infected cells produced exosomes that are uniquely characterized by their proteomic and RNA profiles that may contribute to disease pathology in AIDS. PMID:23661700

  20. Expression of bovine vitamin K-dependent carboxylase activity in baculovirus-infected insect cells.

    PubMed

    Roth, D A; Rehemtulla, A; Kaufman, R J; Walsh, C T; Furie, B; Furie, B C

    1993-09-15

    A vitamin K-dependent carboxylase has recently been purified from bovine liver microsomes and candidate cDNA clones have been isolated. Definitive identification of the carboxylase remains circumstantial since expression of candidate carboxylase cDNAs in mammalian cells is confounded by the presence of endogenous carboxylase activity. To overcome this problem, a recombinant strain of baculovirus (Autographa california nuclear polyhedrosis virus, AcMNPV) encoding a putative carboxylase (vbCbx/AcMNPV) was used to infect Sf9 insect cells, which we demonstrate have no endogenous carboxylase activity. Infection with vbCbx/AcMNPV conferred vitamin K-dependent carboxylase activity to Sf9 insect cells. Carboxylase activity was demonstrated to peak 2-3 days after infection with vbCbx/AcMNPV. Metabolic radiolabeling with L-[35S]methionine revealed that the 90-kDa recombinant protein is the major protein synthesized at the time of peak activity after infection. An anti-peptide antibody directed against residues 86-99 reacted with bovine liver carboxylase on Western blot analysis and immunoprecipitated recombinant carboxylase from infected Sf9 microsomal protein preparations. Since Sf9 insect cells lack endogenous vitamin K-dependent carboxylase activity, expression of carboxylase activity in Sf9 insect cells with recombinant baculovirus demonstrates that the protein encoded by this cDNA is a vitamin K-dependent gamma-glutamyl carboxylase. PMID:8378308

  1. Hybrid spreading mechanisms and T cell activation shape the dynamics of HIV-1 infection.

    PubMed

    Zhang, Changwang; Zhou, Shi; Groppelli, Elisabetta; Pellegrino, Pierre; Williams, Ian; Borrow, Persephone; Chain, Benjamin M; Jolly, Clare

    2015-04-01

    HIV-1 can disseminate between susceptible cells by two mechanisms: cell-free infection following fluid-phase diffusion of virions and by highly-efficient direct cell-to-cell transmission at immune cell contacts. The contribution of this hybrid spreading mechanism, which is also a characteristic of some important computer worm outbreaks, to HIV-1 progression in vivo remains unknown. Here we present a new mathematical model that explicitly incorporates the ability of HIV-1 to use hybrid spreading mechanisms and evaluate the consequences for HIV-1 pathogenenesis. The model captures the major phases of the HIV-1 infection course of a cohort of treatment naive patients and also accurately predicts the results of the Short Pulse Anti-Retroviral Therapy at Seroconversion (SPARTAC) trial. Using this model we find that hybrid spreading is critical to seed and establish infection, and that cell-to-cell spread and increased CD4+ T cell activation are important for HIV-1 progression. Notably, the model predicts that cell-to-cell spread becomes increasingly effective as infection progresses and thus may present a considerable treatment barrier. Deriving predictions of various treatments' influence on HIV-1 progression highlights the importance of earlier intervention and suggests that treatments effectively targeting cell-to-cell HIV-1 spread can delay progression to AIDS. This study suggests that hybrid spreading is a fundamental feature of HIV infection, and provides the mathematical framework incorporating this feature with which to evaluate future therapeutic strategies. PMID:25837979

  2. Highly heterogeneous, activated and short-lived regulatory T cells during chronic filarial infection

    PubMed Central

    Metenou, Simon; Coulibaly, Yaya I.; Sturdevant, Daniel; Dolo, Housseini; Diallo, Abdallah A.; Soumaoro, Lamine; Coulibaly, Michel E.; Kanakabandi, Kishore; Porcella, Stephen F.; Klion, Amy D.; Nutman, Thomas B.

    2016-01-01

    The mechanisms underlying the increase in the numbers of regulatory T (Treg) cells in chronic infection settings remain unclear. Here we have delineated the phenotype and transcriptional profiles of Treg cells from 18 filarial-infected (Fil+) and 19 filarial-uninfected (Fil-) subjects. We found that the frequencies of Foxp3+ Treg cells expressing CTLA-4, GITR, LAG-3 and IL-10 were significantly higher in Fil+ subjects compared with that in Fil- subjects. Foxp3-expressing Treg-cell populations in Fil+ subjects were also more heterogeneous and had higher expression of IL-10, CCL-4, IL-29, CTLA-4 and TGF-β than Fil- subjects, each of these cytokines having been implicated in immune suppression. Moreover, Foxp3-expressing Treg cells from Fil+ subjects had markedly upregulated expression of activation-induced apoptotic genes with concomitant downregulation of those involved in cell survival. To determine whether the expression of apoptotic genes was due to Treg-cell activation, we found that the expression of CTLA-4, CDk8, RAD50, TNFRSF1A, FOXO3 and RHOA were significantly upregulated in stimulated cells compared with unstimulated cells. Taken together, our results suggest that in patent filarial infection, the expanded Treg-cell populations are heterogeneous, short-lived, activated and express higher levels of molecules known to modulate immune responsiveness, suggesting that filarial infection is associated with high Treg-cell turnover. PMID:24737144

  3. PPARγ Is Activated during Congenital Cytomegalovirus Infection and Inhibits Neuronogenesis from Human Neural Stem Cells

    PubMed Central

    Rolland, Maude; Li, Xiaojun; Perez-Berezo, Teresa; Rauwel, Benjamin; Benchoua, Alexandra; Bessières, Bettina; Aziza, Jacqueline; Cenac, Nicolas; Luo, Minhua; Casper, Charlotte; Peschanski, Marc; Gonzalez-Dunia, Daniel; Leruez-Ville, Marianne; Davrinche, Christian; Chavanas, Stéphane

    2016-01-01

    Congenital infection by human cytomegalovirus (HCMV) is a leading cause of permanent sequelae of the central nervous system, including sensorineural deafness, cerebral palsies or devastating neurodevelopmental abnormalities (0.1% of all births). To gain insight on the impact of HCMV on neuronal development, we used both neural stem cells from human embryonic stem cells (NSC) and brain sections from infected fetuses and investigated the outcomes of infection on Peroxisome Proliferator-Activated Receptor gamma (PPARγ), a transcription factor critical in the developing brain. We observed that HCMV infection dramatically impaired the rate of neuronogenesis and strongly increased PPARγ levels and activity. Consistent with these findings, levels of 9-hydroxyoctadecadienoic acid (9-HODE), a known PPARγ agonist, were significantly increased in infected NSCs. Likewise, exposure of uninfected NSCs to 9-HODE recapitulated the effect of infection on PPARγ activity. It also increased the rate of cells expressing the IE antigen in HCMV-infected NSCs. Further, we demonstrated that (1) pharmacological activation of ectopically expressed PPARγ was sufficient to induce impaired neuronogenesis of uninfected NSCs, (2) treatment of uninfected NSCs with 9-HODE impaired NSC differentiation and (3) treatment of HCMV-infected NSCs with the PPARγ inhibitor T0070907 restored a normal rate of differentiation. The role of PPARγ in the disease phenotype was strongly supported by the immunodetection of nuclear PPARγ in brain germinative zones of congenitally infected fetuses (N = 20), but not in control samples. Altogether, our findings reveal a key role for PPARγ in neurogenesis and in the pathophysiology of HCMV congenital infection. They also pave the way to the identification of PPARγ gene targets in the infected brain. PMID:27078877

  4. Safety and Efficacy of Activated Transfected Killer Cells for Neutropenic Fungal Infections

    PubMed Central

    Lin, Lin; Ibrahim, Ashraf S.; Baquir, Beverlie; Fu, Yue; Applebaum, David; Schwartz, Julie; Wang, Amy; Avanesian, Valentina; Spellberg, Brad

    2010-01-01

    Background Invasive fungal infections cause considerable morbidity and mortality in neutropenic patients. White blood cell transfusions are a promising treatment for such infections, but technical barriers have prevented their widespread use. Methods To recapitulate white blood cell transfusions, we are developing a cell-based immunotherapy using a phagocytic cell line, HL-60. We sought to stably transfect HL-60 cells with a suicide trap (herpes simplex virus thymidine kinase), to enable purging of the cells when desired, and a bioluminescence marker, to track the cells in vivo in mice. Results Transfection was stable despite 20 months of continuous culture or storage in liquid nitrogen. Activation of these transfected cells with retinoic acid and dimethyl sulfamethoxazole enhanced their microbicidal effects. Activated transfected killer (ATAK) cells were completely eliminated after exposure to ganciclovir, confirming function of the suicide trap. ATAK cells improved the survival of neutropenic mice with lethal disseminated candidiasis and inhalational aspergillosis. Bioluminescence and histopathologic analysis confirmed that the cells were purged from surviving mice after ganciclovir treatment. Comprehensive necropsy, histopathology, and metabolomic analysis revealed no toxicity of the cells. Conclusions These results lay the groundwork for continued translational development of this promising, novel technology for the treatment of refractory infections in neutropenic hosts. PMID:20397927

  5. The activation of p38MAPK and JNK pathways in bovine herpesvirus 1 infected MDBK cells.

    PubMed

    Zhu, Liqian; Yuan, Chen; Huang, Liyuan; Ding, Xiuyan; Wang, Jianye; Zhang, Dong; Zhu, Guoqiang

    2016-01-01

    We have shown previously that BHV-1 infection activates Erk1/2 signaling. Here, we show that BHV-1 provoked an early-stage transient and late-stage sustained activation of JNK, p38MAPK and c-Jun signaling in MDBK cells. C-Jun phosphorylation was dependent on JNK. These early events were partially due to the viral entry process. Unexpectedly, reactive oxygen species were not involved in the later activation phase. Interestingly, only activated JNK facilitated the viral multiplication identified through both chemical inhibitor and siRNA. Collectively, this study provides insight into our understanding of early stages of BHV-1 infection. PMID:27590675

  6. Mechanisms by Which Interleukin-12 Corrects Defective NK Cell Anticryptococcal Activity in HIV-Infected Patients

    PubMed Central

    Kyei, Stephen K.; Ogbomo, Henry; Li, ShuShun; Timm-McCann, Martina; Xiang, Richard F.; Huston, Shaunna M.; Ganguly, Anutosh; Colarusso, Pina; Gill, M. John

    2016-01-01

    ABSTRACT Cryptococcus neoformans is a pathogenic yeast and a leading cause of life-threatening meningitis in AIDS patients. Natural killer (NK) cells are important immune effector cells that directly recognize and kill C. neoformans via a perforin-dependent cytotoxic mechanism. We previously showed that NK cells from HIV-infected patients have aberrant anticryptococcal killing and that interleukin-12 (IL-12) restores the activity at least partially through restoration of NKp30. However, the mechanisms causing this defect or how IL-12 restores the function was unknown. By examining the sequential steps in NK cell killing of Cryptococcus, we found that NK cells from HIV-infected patients had defective binding of NK cells to C. neoformans. Moreover, those NK cells that bound to C. neoformans failed to polarize perforin-containing granules to the microbial synapse compared to healthy controls, suggesting that binding was insufficient to restore a defect in perforin polarization. We also identified lower expression of intracellular perforin and defective perforin release from NK cells of HIV-infected patients in response to C. neoformans. Importantly, treatment of NK cells from HIV-infected patients with IL-12 reversed the multiple defects in binding, granule polarization, perforin content, and perforin release and restored anticryptococcal activity. Thus, there are multiple defects in the cytolytic machinery of NK cells from HIV-infected patients, which cumulatively result in defective NK cell anticryptococcal activity, and each of these defects can be reversed with IL-12. PMID:27555306

  7. Membrane-bound complement regulatory activity is decreased on vaccinia virus-infected cells.

    PubMed Central

    Baranyi, L; Okada, N; Baranji, K; Takizawa, H; Okada, H

    1994-01-01

    Decay accelerating factor (DAF), membrane cofactor protein (MCP), complement receptor 1 and mouse Crry are cell surface-bound complement regulatory proteins capable of inhibiting C3 convertase activity on cell membranes, and therefore provide a substantial protection from attack by homologous complement activated either by the classical or by the alternative pathway. Decrease in complement regulatory activity might lead to spontaneous complement deposition and subsequent cell injury. MoAb 5I2 can inhibit the complement regulatory activity of molecules on rat cells, resulting in deposition of homologous complement. The antigen recognized by 5I2 MoAb in rats is homologous to mouse Crry. Fifteen to 20 h after infection with vaccinia virus, in vitro cultured KDH-8 rat hepatoma cells show a strong decrease in expression of Crry-like antigen, and proved to be sensitive to complement deposition when 1:5 diluted normal rat serum was added to the culture medium as a source of complement. Addition of complement to the cultured KDH-8 cells infected with a very low dose of vaccinia virus (1 plaque-forming unit (PFU)/1000 cells) substantially reduced spreading of virus infection in the cell culture, while inactivation of complement by heat or zymosan treatment abrogated the protective effect. PMID:7923872

  8. PKR Activation Favors Infectious Pancreatic Necrosis Virus Replication in Infected Cells

    PubMed Central

    Gamil, Amr A.A.; Xu, Cheng; Mutoloki, Stephen; Evensen, Øystein

    2016-01-01

    The double-stranded RNA-activated protein kinase R (PKR) is a Type I interferon (IFN) stimulated gene that has important biological and immunological functions. In viral infections, in general, PKR inhibits or promotes viral replication, but PKR-IPNV interaction has not been previously studied. We investigated the involvement of PKR during infectious pancreatic necrosis virus (IPNV) infection using a custom-made rabbit antiserum and the PKR inhibitor C16. Reactivity of the antiserum to PKR in CHSE-214 cells was confirmed after IFNα treatment giving an increased protein level. IPNV infection alone did not give increased PKR levels by Western blot, while pre-treatment with PKR inhibitor before IPNV infection gave decreased eukaryotic initiation factor 2-alpha (eIF2α) phosphorylation. This suggests that PKR, despite not being upregulated, is involved in eIF2α phosphorylation during IPNV infection. PKR inhibitor pre-treatment resulted in decreased virus titers, extra- and intracellularly, concomitant with reduction of cells with compromised membranes in IPNV-permissive cell lines. These findings suggest that IPNV uses PKR activation to promote virus replication in infected cells. PMID:27338445

  9. PKR Activation Favors Infectious Pancreatic Necrosis Virus Replication in Infected Cells.

    PubMed

    Gamil, Amr A A; Xu, Cheng; Mutoloki, Stephen; Evensen, Øystein

    2016-01-01

    The double-stranded RNA-activated protein kinase R (PKR) is a Type I interferon (IFN) stimulated gene that has important biological and immunological functions. In viral infections, in general, PKR inhibits or promotes viral replication, but PKR-IPNV interaction has not been previously studied. We investigated the involvement of PKR during infectious pancreatic necrosis virus (IPNV) infection using a custom-made rabbit antiserum and the PKR inhibitor C16. Reactivity of the antiserum to PKR in CHSE-214 cells was confirmed after IFNα treatment giving an increased protein level. IPNV infection alone did not give increased PKR levels by Western blot, while pre-treatment with PKR inhibitor before IPNV infection gave decreased eukaryotic initiation factor 2-alpha (eIF2α) phosphorylation. This suggests that PKR, despite not being upregulated, is involved in eIF2α phosphorylation during IPNV infection. PKR inhibitor pre-treatment resulted in decreased virus titers, extra- and intracellularly, concomitant with reduction of cells with compromised membranes in IPNV-permissive cell lines. These findings suggest that IPNV uses PKR activation to promote virus replication in infected cells. PMID:27338445

  10. Activation and Recruitment of Regulatory T Cells via Chemokine Receptor Activation in Trichinella spiralis-Infected Mice

    PubMed Central

    Ahn, Jeong-Bin; Kang, Shin Ae; Kim, Dong-Hee; Yu, Hak Sun

    2016-01-01

    As most infections by the helminth parasite elicit the recruitment of CD4+CD25+Foxp3+ T (Treg) cells, many scientists have suggested that these cells could be used for the treatment of immune-mediated inflammation and associated diseases. In order to investigate the distribution and alteration of activated Treg cells, we compared the expression levels of Treg cell activation markers in the ileum and gastrocnemius tissues 1, 2, and 4 weeks after infection. The number of Treg cells was monitored using GFP-coded Foxp3 transgenic mice. In mice at 1 week after Trichinella spiralis infection, the number of activated Treg cells was higher than in the control group. In mice at 2 weeks after infection, there was a significant increase in the number of cells expressing Foxp3 and CTLA-4 when compared to the control group and mice at 1 week after infection. At 4 weeks after infection, T. spiralis was easily identifiable in nurse cells in mouse muscles. In the intestine, the expression of Gzmb and Klrg1 decreased over time and that of Capg remained unchanged for the first and second week, then decreased in the 4th week. However, in the muscles, the expression of most chemokine genes was increased due to T. spiralis infection, in particular the expression levels of Gzmb, OX40, and CTLA-4 increased until week 4. In addition, increased gene expression of all chemokine receptors in muscle, CXCR3, CCR4, CCR5, CCR9, and CCR10, was observed up until the 4th week. In conclusion, various chemokine receptors showed increased expressions combined with recruitment of Treg cells in the muscle tissue. PMID:27180574

  11. Activation and Recruitment of Regulatory T Cells via Chemokine Receptor Activation in Trichinella spiralis-Infected Mice.

    PubMed

    Ahn, Jeong-Bin; Kang, Shin Ae; Kim, Dong-Hee; Yu, Hak Sun

    2016-04-01

    As most infections by the helminth parasite elicit the recruitment of CD4(+)CD25(+)Foxp3(+) T (Treg) cells, many scientists have suggested that these cells could be used for the treatment of immune-mediated inflammation and associated diseases. In order to investigate the distribution and alteration of activated Treg cells, we compared the expression levels of Treg cell activation markers in the ileum and gastrocnemius tissues 1, 2, and 4 weeks after infection. The number of Treg cells was monitored using GFP-coded Foxp3 transgenic mice. In mice at 1 week after Trichinella spiralis infection, the number of activated Treg cells was higher than in the control group. In mice at 2 weeks after infection, there was a significant increase in the number of cells expressing Foxp3 and CTLA-4 when compared to the control group and mice at 1 week after infection. At 4 weeks after infection, T. spiralis was easily identifiable in nurse cells in mouse muscles. In the intestine, the expression of Gzmb and Klrg1 decreased over time and that of Capg remained unchanged for the first and second week, then decreased in the 4th week. However, in the muscles, the expression of most chemokine genes was increased due to T. spiralis infection, in particular the expression levels of Gzmb, OX40, and CTLA-4 increased until week 4. In addition, increased gene expression of all chemokine receptors in muscle, CXCR3, CCR4, CCR5, CCR9, and CCR10, was observed up until the 4th week. In conclusion, various chemokine receptors showed increased expressions combined with recruitment of Treg cells in the muscle tissue. PMID:27180574

  12. Activation-induced apoptosis in peripheral blood mononuclear cells during hepatosplenic Schistosoma mansoni infections.

    PubMed

    Ghoneim, H M; Demian, S R; Heshmat, M G; Ismail, N S; El-Sayed, Laila H

    2008-01-01

    It is well established that programmed cell death (apoptosis) is an important regulator of host responses during infection with a variety of intra- and extra-cellular pathogens. The present work aimed at assessment of in vitro spontaneous and phytohemagglutinin (PHA)-induced apoptosis in mononuclear cells isolated from patients with hepatosplenic form of S. mansoni infections. Cell death data were correlated to the degree of lymphoproliferative responses to PHA as well as to the serum anti-schistosomal antibody titers. A markedly significant increase in PHA-induced apoptosis in lymphocytes isolated from S. mansoni-infected patients was seen when compared to the corresponding healthy controls. However, a slight difference was recorded between the two studied groups regarding the spontaneous apoptosis. This was accompanied with a significant impairment of in vitro PHA-induced lymphoproliferation of T cells from S. mansoni patients. Data of the present study supports the hypothesis that activation-induced cell death (AICD) is a potentially contributing factor in T helper (Th) cell regulation during chronic stages of schistosomiasis, which represents a critically determinant factor in the host-parasite interaction and might influence the destiny of parasitic infections either towards establishment of chronic infection or towards host death.

  13. Activation-induced apoptosis in peripheral blood mononuclear cells during hepatosplenic Schistosoma mansoni infections.

    PubMed

    Ghoneim, H M; Demian, S R; Heshmat, M G; Ismail, N S; El-Sayed, Laila H

    2008-01-01

    It is well established that programmed cell death (apoptosis) is an important regulator of host responses during infection with a variety of intra- and extra-cellular pathogens. The present work aimed at assessment of in vitro spontaneous and phytohemagglutinin (PHA)-induced apoptosis in mononuclear cells isolated from patients with hepatosplenic form of S. mansoni infections. Cell death data were correlated to the degree of lymphoproliferative responses to PHA as well as to the serum anti-schistosomal antibody titers. A markedly significant increase in PHA-induced apoptosis in lymphocytes isolated from S. mansoni-infected patients was seen when compared to the corresponding healthy controls. However, a slight difference was recorded between the two studied groups regarding the spontaneous apoptosis. This was accompanied with a significant impairment of in vitro PHA-induced lymphoproliferation of T cells from S. mansoni patients. Data of the present study supports the hypothesis that activation-induced cell death (AICD) is a potentially contributing factor in T helper (Th) cell regulation during chronic stages of schistosomiasis, which represents a critically determinant factor in the host-parasite interaction and might influence the destiny of parasitic infections either towards establishment of chronic infection or towards host death. PMID:20306689

  14. Mast cell activation by conidia of Sporothrix schenckii: role in the severity of infection.

    PubMed

    Romo-Lozano, Y; Hernández-Hernández, F; Salinas, E

    2012-07-01

    Mast cells are abundant in the skin and other peripheral tissues, where they are one of the first immune cells to make contact with invading pathogens. As a result of pathogen recognition, mast cells can be activated and release different preformed and de novo-synthesized mediators. Sporothrix schenckii is the fungus that causes sporotrichosis, a worldwide-distributed subcutaneous mycosis considered as an important emerging health problem. It remains unknown whether or not mast cells are activated by S. schenckii. Here, we investigated the in vitro response of mast cells to conidia of S. schenckii and their in vivo involvement in sporotrichosis. Mast cells became activated after interaction with conidia, releasing early response cytokines as TNF-α and IL-6. Although histamine release was not significantly stimulated by S. schenckii, we determined that conidia potentiate histamine secretion induced by compound 48/80. Furthermore, functional depletion of peritoneal mast cells before S. schenckii infection significantly reduced the severity of cutaneous lesions of the sporotrichosis. These data demonstrate that mast cells are important contributors in the host response to S. schenckii infection, suggesting a role of these cells in the progress of clinical manifestations in sporotrichosis. PMID:22486186

  15. Mast cell activation by conidia of Sporothrix schenckii: role in the severity of infection.

    PubMed

    Romo-Lozano, Y; Hernández-Hernández, F; Salinas, E

    2012-07-01

    Mast cells are abundant in the skin and other peripheral tissues, where they are one of the first immune cells to make contact with invading pathogens. As a result of pathogen recognition, mast cells can be activated and release different preformed and de novo-synthesized mediators. Sporothrix schenckii is the fungus that causes sporotrichosis, a worldwide-distributed subcutaneous mycosis considered as an important emerging health problem. It remains unknown whether or not mast cells are activated by S. schenckii. Here, we investigated the in vitro response of mast cells to conidia of S. schenckii and their in vivo involvement in sporotrichosis. Mast cells became activated after interaction with conidia, releasing early response cytokines as TNF-α and IL-6. Although histamine release was not significantly stimulated by S. schenckii, we determined that conidia potentiate histamine secretion induced by compound 48/80. Furthermore, functional depletion of peritoneal mast cells before S. schenckii infection significantly reduced the severity of cutaneous lesions of the sporotrichosis. These data demonstrate that mast cells are important contributors in the host response to S. schenckii infection, suggesting a role of these cells in the progress of clinical manifestations in sporotrichosis.

  16. Activation of pulmonary and lymph node dendritic cells during chronic Pseudomonas aeruginosa lung infection in mice.

    PubMed

    Damlund, Dina Silke Malling; Christophersen, Lars; Jensen, Peter Østrup; Alhede, Morten; Høiby, Niels; Moser, Claus

    2016-06-01

    The majority of cystic fibrosis (CF) patients acquire chronic Pseudomonas aeruginosa lung infection, resulting in increased mortality and morbidity. The chronic P. aeruginosa lung infection is characterized by bacteria growing in biofilm surrounded by polymorphonuclear neutrophils (PMNs). However, the infection is not eradicated and the inflammatory response leads to gradual degradation of the lung tissue. In CF patients, a Th2-dominated adaptive immune response with a pronounced antibody response is correlated with poorer outcome. Dendritic cells (DCs) are crucial in bridging the innate immune system with the adaptive immune response. Once activated, the DCs deliver a set of signals to uncommitted T cells that induce development, such as expansion of regulatory T cells and polarization of Th1, Th2 or Th17 subsets. In this study, we characterized DCs in lungs and regional lymph nodes in BALB/c mice infected using intratracheal installation of P. aeruginosa embedded in seaweed alginate in the lungs. A significantly elevated concentration of DCs was detected earlier in the lungs than in the regional lymph nodes. To evaluate whether the chronic P. aeruginosa lung infection leads to activation of DCs, costimulatory molecules CD80 and CD86 were analyzed. During infection, the DCs showed significant elevation of CD80 and CD86 expression in both the lungs and the regional lymph nodes. Interestingly, the percentage of CD86-positive cells was significantly higher than the percentage of CD80-positive cells in the lymph nodes. In addition, cytokine production from Lipopolysaccharides (LPS)-stimulated DCs was analyzed demonstrating elevated production of IL-6, IL-10 and IL-12. However, production of IL-12 was suppressed earlier than IL-6 and IL-10. These results support that DCs are involved in skewing of the Th1/Th2 balance in CF and may be a possible treatment target. PMID:27009697

  17. Nuclear factor of activated T-cells (NFAT) plays a role in SV40 infection

    SciTech Connect

    Manley, Kate; O'Hara, Bethany A.; Atwood, Walter J.

    2008-03-01

    Recent evidence highlighted a role for the transcription factor, nuclear factor of activated T-cells (NFAT), in the transcription of the human polyomavirus JCV. Here we show that NFAT is also important in the transcriptional control of the related polyomavirus, Simian Virus 40 (SV40). Inhibition of NFAT activity reduced SV40 infection of Vero, 293A, and HeLa cells, and this block occurred at the stage of viral transcription. Both NFAT3 and NFAT4 bound to the SV40 promoter through {kappa}B sites located within the 72 bp repeated enhancer region. In Vero cells, NFAT was involved in late transcription, but in HeLa and 293A cells both early and late viral transcription required NFAT activity. SV40 large T-Ag was found to increase NFAT activity and provided a positive feedback loop to transactivate the SV40 promoter.

  18. Activated human valvular interstitial cells sustain interleukin-17 production to recruit neutrophils in infective endocarditis.

    PubMed

    Yeh, Chiou-Yueh; Shun, Chia-Tung; Kuo, Yu-Min; Jung, Chiau-Jing; Hsieh, Song-Chou; Chiu, Yen-Ling; Chen, Jeng-Wei; Hsu, Ron-Bin; Yang, Chia-Ju; Chia, Jean-San

    2015-06-01

    The mechanisms that underlie valvular inflammation in streptococcus-induced infective endocarditis (IE) remain unclear. We previously demonstrated that streptococcal glucosyltransferases (GTFs) can activate human heart valvular interstitial cells (VIC) to secrete interleukin-6 (IL-6), a cytokine involved in T helper 17 (Th17) cell differentiation. Here, we tested the hypothesis that activated VIC can enhance neutrophil infiltration through sustained IL-17 production, leading to valvular damage. To monitor cytokine and chemokine production, leukocyte recruitment, and the induction or expansion of CD4(+) CD45RA(-) CD25(-) CCR6(+) Th17 cells, primary human VIC were cultured in vitro and activated by GTFs. Serum cytokine levels were measured using an enzyme-linked immunosorbent assay (ELISA), and neutrophils and Th17 cells were detected by immunohistochemistry in infected valves from patients with IE. The expression of IL-21, IL-23, IL-17, and retinoic acid receptor-related orphan receptor C (Rorc) was upregulated in GTF-activated VIC, which may enhance the proliferation of memory Th17 cells in an IL-6-dependent manner. Many chemokines, including chemokine (C-X-C motif) ligand 1 (CXCL1), were upregulated in GTF-activated VIC, which might recruit neutrophils and CD4(+) T cells. Moreover, CXCL1 production in VIC was induced in a dose-dependent manner by IL-17 to enhance neutrophil chemotaxis. CXCL1-expressing VIC and infiltrating neutrophils could be detected in infected valves, and serum concentrations of IL-17, IL-21, and IL-23 were increased in patients with IE compared to healthy donors. Furthermore, elevated serum IL-21 levels have been significantly associated with severe valvular damage, including rupture of chordae tendineae, in IE patients. Our findings suggest that VIC are activated by bacterial modulins to recruit neutrophils and that such activities might be further enhanced by the production of Th17-associated cytokines. Together, these factors can amplify

  19. Comparative analysis of signature genes in PRRSV-infected porcine monocyte-derived dendritic cells at differential activation statuses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Activation statuses of monocytic cells including monocytes, macrophages and dendritic cells (DCs) are critically important for antiviral immunity. In particular, some devastating viruses, including porcine reproductive and respiratory syndrome virus (PRRSV), are capable of directly infecting these c...

  20. Cytokine profile and natural killer cell activity in Listeria monocytogenes infected mice treated orally with Petiveria alliacea extract.

    PubMed

    Queiroz, M L; Quadros, M R; Santos, L M

    2000-08-01

    In this work, we investigated the effects of Petiveria alliacea extract on the production of Th1-type and Th2-type cytokines and on NK cells activity in normal and Listeria monocytogenes infected mice. Our results demonstrated that in normal/non-infected mice P. alliacea administration led to increased levels of Interleukin-2 (IL-2). The infection alone enhanced INF-gamma levels and NK cell activity at 48 and 72 hours of infection. The treatment with five consecutive doses of 1000 mg/kg/day of P. alliacea extract, given previously to infection, led to further increases in IL-2 levels, in relation to normal/non-infected/P. alliacea treated controls, and in INF-gamma levels at 72 h of infection, compared to infected mice. On the other hand, the production of IL-4 and IL-10 were not altered either by the infection or by the treatment with P. alliacea extract. NK cells activity increased at 48 h and 72 h following the inoculation of the bacteria. When mice were treated with P. alliacea previously to infection, NK activity was higher than that observed at 48 h, 72 h and 120 h of infection in the infected animal. Based on these findings we suggest that P. alliacea up-regulates anti-bacterial immune response by enhancing both Th1 function and the activity of NK cells.

  1. Early Activation of Teleost B Cells in Response to Rhabdovirus Infection

    PubMed Central

    Abós, Beatriz; Castro, Rosario; González Granja, Aitor; Havixbeck, Jeffrey J.; Barreda, Daniel R.

    2014-01-01

    ABSTRACT To date, the response of teleost B cells to specific pathogens has been only scarcely addressed. In this work, we have demonstrated that viral hemorrhagic septicemia virus (VHSV), a fish rhabdovirus, has the capacity to infect rainbow trout spleen IgM-positive (IgM+) cells, although the infection is not productive. Consequently, we have studied the effects of VHSV on IgM+ cell functionality, comparing these effects to those elicited by a Toll-like receptor 3 (TLR3) ligand, poly(I·C). We found that poly(I·C) and VHSV significantly upregulated TLR3 and type I interferon (IFN) transcription in spleen and blood IgM+ cells. Further effects included the upregulated transcription of the CK5B chemokine. The significant inhibition of some of these effects in the presence of bafilomycin A1 (BAF), an inhibitor of endosomal acidification, suggests the involvement of an intracellular TLR in these responses. In the case of VHSV, these transcriptional effects were dependent on viral entry into B cells and the initiation of viral transcription. VHSV also provoked the activation of NF-κB and the upregulation of major histocompatibility complex class II (MHC-II) cell surface expression on IgM+ cells, which, along with the increased transcription of the costimulatory molecules CD80/86 and CD83, pointed to VHSV-induced IgM+ cell activation toward an antigen-presenting profile. Finally, despite the moderate effects of VHSV on IgM+ cell proliferation, a consistent effect on IgM+ cell survival was detected. IMPORTANCE Innate immune responses to pathogens established through their recognition by pattern recognition receptors (PRRs) have been traditionally ascribed to innate cells. However, recent evidence in mammals has revealed that innate pathogen recognition by B lymphocytes is a crucial factor in shaping the type of immune response that is mounted. In teleosts, these immediate effects of viral encounter on B lymphocytes have not been addressed to date. In our study, we

  2. In vitro culture of coxsackievirus group B, type 3 immune spleen cells on infected endothelial cells and biological activity of the cultured cells in vivo.

    PubMed Central

    Huber, S A; Job, L P; Woodruff, J F

    1984-01-01

    Spleen cells from male BALB/c mice infected 7 days earlier by an intraperitoneal injection of 3 X 10(4) PFU of a myocarditic strain of coxsackievirus B-3 lysed virus-infected endothelial cells in a 51Cr release assay. Cytotoxic activity in the in vivo sensitized spleen cell population could be further increased by culturing the immune spleen cells from infected mice on virus-infected or uninfected endothelial cells for 6 to 7 days in vitro. Cytotoxicity of in vitro cultured spleen cells to infected targets was mediated by T lymphocytes since reactivity was abolished by treatment of the spleen cells with anti-thy 1.2 serum and complement. Reciprocal assays with BALB/c and C57BL cells indicated that maximum cytotoxicity occurred when spleen cells were sensitized on syngeneic endothelial cells. Other experiments showed that spleen cells sensitized to coxsackievirus B-3 or encephalomyocarditis virus were selectively cytolytic to targets infected with the homologous virus. Adoptive transfer of T cells cultured in vitro on infected endothelial cells retained their ability to induce myocarditis in T-lymphocyte-deficient mice. Images PMID:6319285

  3. Stress responses in flavivirus-infected cells: activation of unfolded protein response and autophagy.

    PubMed

    Blázquez, Ana-Belén; Escribano-Romero, Estela; Merino-Ramos, Teresa; Saiz, Juan-Carlos; Martín-Acebes, Miguel A

    2014-01-01

    The Flavivirus is a genus of RNA viruses that includes multiple long known human, animal, and zoonotic pathogens such as Dengue virus, yellow fever virus, West Nile virus, or Japanese encephalitis virus, as well as other less known viruses that represent potential threats for human and animal health such as Usutu or Zika viruses. Flavivirus replication is based on endoplasmic reticulum-derived structures. Membrane remodeling and accumulation of viral factors induce endoplasmic reticulum stress that results in activation of a cellular signaling response termed unfolded protein response (UPR), which can be modulated by the viruses for their own benefit. Concomitant with the activation of the UPR, an upregulation of the autophagic pathway in cells infected with different flaviviruses has also been described. This review addresses the current knowledge of the relationship between endoplasmic reticulum stress, UPR, and autophagy in flavivirus-infected cells and the growing evidences for an involvement of these cellular pathways in the replication and pathogenesis of these viruses.

  4. Exhaustion of Activated CD8 T Cells Predicts Disease Progression in Primary HIV-1 Infection

    PubMed Central

    Hickling, Stephen; Hurst, Jacob; Meyerowitz, Jodi; Willberg, Christian B.; Robinson, Nicola; Brown, Helen; Kinloch, Sabine; Babiker, Abdel; Nwokolo, Nneka; Fox, Julie; Fidler, Sarah; Phillips, Rodney; Frater, John

    2016-01-01

    The rate at which HIV-1 infected individuals progress to AIDS is highly variable and impacted by T cell immunity. CD8 T cell inhibitory molecules are up-regulated in HIV-1 infection and associate with immune dysfunction. We evaluated participants (n = 122) recruited to the SPARTAC randomised clinical trial to determine whether CD8 T cell exhaustion markers PD-1, Lag-3 and Tim-3 were associated with immune activation and disease progression. Expression of PD-1, Tim-3, Lag-3 and CD38 on CD8 T cells from the closest pre-therapy time-point to seroconversion was measured by flow cytometry, and correlated with surrogate markers of HIV-1 disease (HIV-1 plasma viral load (pVL) and CD4 T cell count) and the trial endpoint (time to CD4 count <350 cells/μl or initiation of antiretroviral therapy). To explore the functional significance of these markers, co-expression of Eomes, T-bet and CD39 was assessed. Expression of PD-1 on CD8 and CD38 CD8 T cells correlated with pVL and CD4 count at baseline, and predicted time to the trial endpoint. Lag-3 expression was associated with pVL but not CD4 count. For all exhaustion markers, expression of CD38 on CD8 T cells increased the strength of associations. In Cox models, progression to the trial endpoint was most marked for PD-1/CD38 co-expressing cells, with evidence for a stronger effect within 12 weeks from confirmed diagnosis of PHI. The effect of PD-1 and Lag-3 expression on CD8 T cells retained statistical significance in Cox proportional hazards models including antiretroviral therapy and CD4 count, but not pVL as co-variants. Expression of ‘exhaustion’ or ‘immune checkpoint’ markers in early HIV-1 infection is associated with clinical progression and is impacted by immune activation and the duration of infection. New markers to identify exhausted T cells and novel interventions to reverse exhaustion may inform the development of novel immunotherapeutic approaches. PMID:27415828

  5. Exhaustion of Activated CD8 T Cells Predicts Disease Progression in Primary HIV-1 Infection.

    PubMed

    Hoffmann, Matthias; Pantazis, Nikos; Martin, Genevieve E; Hickling, Stephen; Hurst, Jacob; Meyerowitz, Jodi; Willberg, Christian B; Robinson, Nicola; Brown, Helen; Fisher, Martin; Kinloch, Sabine; Babiker, Abdel; Weber, Jonathan; Nwokolo, Nneka; Fox, Julie; Fidler, Sarah; Phillips, Rodney; Frater, John

    2016-07-01

    The rate at which HIV-1 infected individuals progress to AIDS is highly variable and impacted by T cell immunity. CD8 T cell inhibitory molecules are up-regulated in HIV-1 infection and associate with immune dysfunction. We evaluated participants (n = 122) recruited to the SPARTAC randomised clinical trial to determine whether CD8 T cell exhaustion markers PD-1, Lag-3 and Tim-3 were associated with immune activation and disease progression. Expression of PD-1, Tim-3, Lag-3 and CD38 on CD8 T cells from the closest pre-therapy time-point to seroconversion was measured by flow cytometry, and correlated with surrogate markers of HIV-1 disease (HIV-1 plasma viral load (pVL) and CD4 T cell count) and the trial endpoint (time to CD4 count <350 cells/μl or initiation of antiretroviral therapy). To explore the functional significance of these markers, co-expression of Eomes, T-bet and CD39 was assessed. Expression of PD-1 on CD8 and CD38 CD8 T cells correlated with pVL and CD4 count at baseline, and predicted time to the trial endpoint. Lag-3 expression was associated with pVL but not CD4 count. For all exhaustion markers, expression of CD38 on CD8 T cells increased the strength of associations. In Cox models, progression to the trial endpoint was most marked for PD-1/CD38 co-expressing cells, with evidence for a stronger effect within 12 weeks from confirmed diagnosis of PHI. The effect of PD-1 and Lag-3 expression on CD8 T cells retained statistical significance in Cox proportional hazards models including antiretroviral therapy and CD4 count, but not pVL as co-variants. Expression of 'exhaustion' or 'immune checkpoint' markers in early HIV-1 infection is associated with clinical progression and is impacted by immune activation and the duration of infection. New markers to identify exhausted T cells and novel interventions to reverse exhaustion may inform the development of novel immunotherapeutic approaches. PMID:27415828

  6. Innate immune response during Yersinia infection: critical modulation of cell death mechanisms through phagocyte activation

    PubMed Central

    Bergsbaken, Tessa; Cookson, Brad T.

    2009-01-01

    Yersinia pestis, the etiological agent of plague, is one of the most deadly pathogens on our planet. This organism shares important attributes with its ancestral progenitor, Yersinia pseudotuberculosis, including a 70-kb virulence plasmid, lymphotropism during growth in the mammalian host, and killing of host macrophages. Infections with both organisms are biphasic, where bacterial replication occurs initially with little inflammation, followed by phagocyte influx, inflammatory cytokine production, and tissue necrosis. During infection, plasmid-encoded attributes facilitate bacterial-induced macrophage death, which results from two distinct processes and corresponds to the inflammatory crescendo observed in vivo: Naïve cells die by apoptosis (noninflammatory), and later in infection, activated macrophages die by pyroptosis (inflammatory). The significance of this redirected cell death for the host is underscored by the importance of phagocyte activation for immunity to Yersinia and the protective role of pyroptosis during host responses to anthrax lethal toxin and infections with Francisella, Legionella, Pseudomonas, and Salmonella. The similarities of Y. pestis and Y. pseudotuberculosis, including conserved, plasmid-encoded functions inducing at least two distinct mechanisms of cell death, indicate that comparative studies are revealing about their critical pathogenic mechanism(s) and host innate immune responses during infection. Validation of this idea and evidence of similar interactions with the host immune system are provided by Y. pseudotuberculosis-priming, cross-protective immunity against Y. pestis. Despite these insights, additional studies indicate much remains to be understood concerning effective host responses against Yersinia, including chromosomally encoded attributes that also contribute to bacterial evasion and modulation of innate and adaptive immune responses. PMID:19734471

  7. Virion encapsidated HIV-1 Vpr induces NFAT to prime non-activated T cells for productive infection.

    PubMed

    Höhne, Kristin; Businger, Ramona; van Nuffel, Anouk; Bolduan, Sebastian; Koppensteiner, Herwig; Baeyens, Ann; Vermeire, Jolien; Malatinkova, Eva; Verhasselt, Bruno; Schindler, Michael

    2016-07-01

    The majority of T cells encountered by HIV-1 are non-activated and do not readily allow productive infection. HIV-1 Vpr is highly abundant in progeny virions, and induces signalling and HIV-1 LTR transcription. We hence hypothesized that Vpr might be a determinant of non-activated T-cell infection. Virion-delivered Vpr activated nuclear factor of activated T cells (NFAT) through Ca(2+) influx and interference with the NFAT export kinase GSK3β. This leads to NFAT translocation and accumulation within the nucleus and was required for productive infection of unstimulated primary CD4(+) T cells. A mutagenesis approach revealed correlation of Vpr-mediated NFAT activation with its ability to enhance LTR transcription and mediate cell cycle arrest. Upon NFAT inhibition, Vpr did not augment resting T-cell infection, and showed reduced G2/M arrest and LTR transactivation. Altogether, Vpr renders unstimulated T cells more permissive for productive HIV-1 infection and stimulates activation of productively infected as well as virus-exposed T cells. Therefore, it could be involved in the establishment and reactivation of HIV-1 from viral reservoirs and might have an impact on the levels of immune activation, which are determinants of HIV-1 pathogenesis.

  8. Virion encapsidated HIV-1 Vpr induces NFAT to prime non-activated T cells for productive infection

    PubMed Central

    Höhne, Kristin; Businger, Ramona; van Nuffel, Anouk; Bolduan, Sebastian; Koppensteiner, Herwig; Baeyens, Ann; Vermeire, Jolien; Malatinkova, Eva; Verhasselt, Bruno; Schindler, Michael

    2016-01-01

    The majority of T cells encountered by HIV-1 are non-activated and do not readily allow productive infection. HIV-1 Vpr is highly abundant in progeny virions, and induces signalling and HIV-1 LTR transcription. We hence hypothesized that Vpr might be a determinant of non-activated T-cell infection. Virion-delivered Vpr activated nuclear factor of activated T cells (NFAT) through Ca2+ influx and interference with the NFAT export kinase GSK3β. This leads to NFAT translocation and accumulation within the nucleus and was required for productive infection of unstimulated primary CD4+ T cells. A mutagenesis approach revealed correlation of Vpr-mediated NFAT activation with its ability to enhance LTR transcription and mediate cell cycle arrest. Upon NFAT inhibition, Vpr did not augment resting T-cell infection, and showed reduced G2/M arrest and LTR transactivation. Altogether, Vpr renders unstimulated T cells more permissive for productive HIV-1 infection and stimulates activation of productively infected as well as virus-exposed T cells. Therefore, it could be involved in the establishment and reactivation of HIV-1 from viral reservoirs and might have an impact on the levels of immune activation, which are determinants of HIV-1 pathogenesis. PMID:27383627

  9. Virion encapsidated HIV-1 Vpr induces NFAT to prime non-activated T cells for productive infection.

    PubMed

    Höhne, Kristin; Businger, Ramona; van Nuffel, Anouk; Bolduan, Sebastian; Koppensteiner, Herwig; Baeyens, Ann; Vermeire, Jolien; Malatinkova, Eva; Verhasselt, Bruno; Schindler, Michael

    2016-07-01

    The majority of T cells encountered by HIV-1 are non-activated and do not readily allow productive infection. HIV-1 Vpr is highly abundant in progeny virions, and induces signalling and HIV-1 LTR transcription. We hence hypothesized that Vpr might be a determinant of non-activated T-cell infection. Virion-delivered Vpr activated nuclear factor of activated T cells (NFAT) through Ca(2+) influx and interference with the NFAT export kinase GSK3β. This leads to NFAT translocation and accumulation within the nucleus and was required for productive infection of unstimulated primary CD4(+) T cells. A mutagenesis approach revealed correlation of Vpr-mediated NFAT activation with its ability to enhance LTR transcription and mediate cell cycle arrest. Upon NFAT inhibition, Vpr did not augment resting T-cell infection, and showed reduced G2/M arrest and LTR transactivation. Altogether, Vpr renders unstimulated T cells more permissive for productive HIV-1 infection and stimulates activation of productively infected as well as virus-exposed T cells. Therefore, it could be involved in the establishment and reactivation of HIV-1 from viral reservoirs and might have an impact on the levels of immune activation, which are determinants of HIV-1 pathogenesis. PMID:27383627

  10. Viral infection. II. Hemin induces overexpression of p67 as it partially prevents appearance of an active p67-deglycosylase in baculovirus-infected insect cells.

    PubMed

    Saha, D; Wu, S; Bose, A; Chatterjee, N; Chakraborty, A; Chatterjee, M; Gupta, N K

    1997-06-15

    The roles of p67-deglycosylase (p67-DG) in the regulation of protein synthesis in baculovirus-infected insect cells were studied. Like vaccinia viral infection, baculovirus infection of insect cells also induced the appearance of a p67-DG. However, p67-DG activity could not be detected because these cells do not contain a detectable level of p67. The baculovirus expression vector system (BEVS), however, promotes significant expression of cloned p67-cDNA. The expression of p67 was significantly enhanced by the addition of hemin to the growth medium. Maximum enhancement was observed at 5 microM hemin. Data suggest that hemin prevents the activation of latent p67-DG inside the cell and does not have any effect on p67 gene transcription. To gain a better understanding of the mechanism of p67-DG activation and hemin stimulation of p67 synthesis, we have now purified p67-DG from baculovirus-infected insect cells. We prepared antibodies against this protein. These antibodies reacted with a 105-kDa protein in cell extracts from the uninfected insect cells (Sf9), KRC-7, and L929 (animal cells). In addition, these antibodies reacted with an additional 60-kDa protein in the cell extracts of baculovirus-infected Sf9 cells and vaccinia virus-infected KRC-7 and L929 cells. Data are also presented to show that the antibodies against p67-DG reacted more efficiently (40%) with the 60-kDa protein in both hemin-deficient reticulocyte lysate and hemin-deficient baculovirus-infected cells. We suggest that hemin prevents the conversion of an inactive p67-DG into an active form possibly by covalent modification such as protein phosphorylation or protein glycosylation. The active form is more efficiently recognized by the p67-DG antibodies since these antibodies were prepared against the active form of p67-DG. PMID:9186500

  11. Innate and cytokine-driven signals, rather than microbial antigens, dominate in natural killer T cell activation during microbial infection

    PubMed Central

    Tatituri, Raju V.V.; Watts, Gerald F.M.; Bhowruth, Veemal; Leadbetter, Elizabeth A.; Barton, Nathaniel; Cohen, Nadia R.; Hsu, Fong-Fu; Besra, Gurdyal S.

    2011-01-01

    Invariant natural killer T cells (iNKT cells) are critical for host defense against a variety of microbial pathogens. However, the central question of how iNKT cells are activated by microbes has not been fully explained. The example of adaptive MHC-restricted T cells, studies using synthetic pharmacological α-galactosylceramides, and the recent discovery of microbial iNKT cell ligands have all suggested that recognition of foreign lipid antigens is the main driver for iNKT cell activation during infection. However, when we compared the role of microbial antigens versus innate cytokine-driven mechanisms, we found that iNKT cell interferon-γ production after in vitro stimulation or infection with diverse bacteria overwhelmingly depended on toll-like receptor–driven IL-12. Importantly, activation of iNKT cells in vivo during infection with Sphingomonas yanoikuyae or Streptococcus pneumoniae, pathogens which are known to express iNKT cell antigens and which require iNKT cells for effective protection, also predominantly depended on IL-12. Constitutive expression of high levels of IL-12 receptor by iNKT cells enabled instant IL-12–induced STAT4 activation, demonstrating that among T cells, iNKT cells are uniquely equipped for immediate, cytokine-driven activation. These findings reveal that innate and cytokine-driven signals, rather than cognate microbial antigen, dominate in iNKT cell activation during microbial infections. PMID:21555485

  12. Porcine parvovirus infection induces apoptosis in PK-15 cells through activation of p53 and mitochondria-mediated pathway

    SciTech Connect

    Zhang, Hongling; Huang, Yong; Du, Qian; Luo, Xiaomao; Zhang, Liang; Zhao, Xiaomin; Tong, Dewen

    2015-01-09

    Highlights: • PPV reduces PK-15 cells viability by inducing apoptosis. • PPV infection induces apoptosis through mitochondria-mediated pathway. • PPV infection activates p53 to regulate the mitochondria apoptotic signaling. - Abstract: Porcine parvovirus (PPV) infection has been reported to induce the cytopathic effects (CPE) in some special host cells and contribute the occurrence of porcine parvovirus disease, but the molecular mechanisms underlying PPV-induced CPE are not clear. In this study, we investigated the morphological and molecular changes of porcine kidney cell line (PK-15 cells) infected with PPV. The results showed that PPV infection inhibited the viability of PK-15 cells in a time and concentration dependent manner. PPV infection induced typical apoptotic features including chromatin condensation, apoptotic body formation, nuclear fragmentation, and Annexin V-binding activity. Further studies showed that Bax was increased and translocated to mitochondria, whereas Bcl-2 was decreased in PPV-infected cells, which caused mitochondrial outer-membrane permeabilization, resulting in the release of mitochondrial cytochrome c, followed by caspase-9 and caspase-3 activation. However, the expression of Fas and Fas ligand (FasL) did not appear significant changes in the process of PPV-induced apoptosis. Moreover, PPV infection activated p53 signaling, which was involved in the activation of apoptotic signaling induced by PPV infection via regulation of Bax and Bcl-2. Taken together, our results demonstrated that PPV infection induced apoptosis in PK-15 cells through activation of p53 and mitochondria-mediated apoptosis pathway. This study may contribute to shed light on the molecular pathogenesis of PPV infection.

  13. Phenotypic and Functional Analysis of Activated Regulatory T Cells Isolated from Chronic Lymphocytic Choriomeningitis Virus-infected Mice.

    PubMed

    Park, Hyo Jin; Oh, Ji Hoon; Ha, Sang-Jun

    2016-01-01

    Regulatory T (Treg) cells, which express Foxp3 as a transcription factor, are subsets of CD4(+) T cells. Treg cells play crucial roles in immune tolerance and homeostasis maintenance by regulating the immune response. The primary role of Treg cells is to suppress the proliferation of effector T (Teff) cells and the production of cytokines such as IFN-γ, TNF-α, and IL-2. It has been demonstrated that Treg cells' ability to inhibit the function of Teff cells is enhanced during persistent pathogen infection and cancer development. To clarify the function of Treg cells under resting or inflamed conditions, a variety of in vitro suppression assays using mouse or human Treg cells have been devised. The main aim of this study is to develop a method to compare the differences in phenotype and suppressive function between resting and activated Treg cells. To isolate activated Treg cells, mice were infected with lymphocytic choriomeningitis virus (LCMV) clone 13 (CL13), a chronic strain of LCMV. Treg cells isolated from the spleen of LCMV CL13-infected mice exhibited both the activated phenotype and enhanced suppressive activity compared with resting Treg cells isolated from naïve mice. Here, we describe the basic protocol for ex vivo phenotype analysis to distinguish activated Treg cells from resting Treg cells. Furthermore, we describe a protocol for the measurement of the suppressive activity of fully activated Treg cells. PMID:27404802

  14. Controlled infection with a therapeutic virus defines the activation kinetics of human natural killer cells in vivo

    PubMed Central

    El-Sherbiny, Y M; Holmes, T D; Wetherill, L F; Black, E V I; Wilson, E B; Phillips, S L; Scott, G B; Adair, R A; Dave, R; Scott, K J; Morgan, R S M; Coffey, M; Toogood, G J; Melcher, A A; Cook, G P

    2015-01-01

    Human natural killer (NK) cells play an important role in anti-viral immunity. However, studying their activation kinetics during infection is highly problematic. A clinical trial of a therapeutic virus provided an opportunity to study human NK cell activation in vivo in a controlled manner. Ten colorectal cancer patients with liver metastases received between one and five doses of oncolytic reovirus prior to surgical resection of their tumour. NK cell surface expression of the interferon-inducible molecules CD69 and tetherin peaked 24–48 h post-infection, coincident with a peak of interferon-induced gene expression. The interferon response and NK cell activation were transient, declining by 96 h post-infection. Furthermore, neither NK cell activation nor the interferon response were sustained in patients undergoing multiple rounds of virus treatment. These results show that reovirus modulates human NK cell activity in vivo and suggest that this may contribute to any therapeutic effect of this oncolytic virus. Detection of a single, transient peak of activation, despite multiple treatment rounds, has implications for the design of reovirus-based therapy. Furthermore, our results suggest the existence of a post-infection refractory period when the interferon response and NK cell activation are blunted. This refractory period has been observed previously in animal models and may underlie the enhanced susceptibility to secondary infections that is seen following viral infection. PMID:25469725

  15. Inhibition of caspase-8 activity reduces IFN-gamma expression by T cells from Leishmania major infection.

    PubMed

    Pereira, Wânia F; Guillermo, Landi V C; Ribeiro-Gomes, Flávia L; Lopes, Marcela F

    2008-03-01

    Following infection with Leishmania major, T cell activation and apoptosis can be detected in draining lymph nodes of C57BL/6-infected mice. We investigated the mechanisms involved in apoptosis and cytokine expression following T cell activation. After two weeks of infection, apoptotic T cells were not detected in draining lymph nodes but activation with anti-CD3 induced apoptosis in both CD4 and CD8 T cells. Treatment with anti-Fas Ligand, caspase-8 or caspase- 9 inhibitors did not block activation-induced T-cell death. We also investigated whether the blockade of caspase-8 activity would affect the expression of type-1 or type-2 cytokines. At early stages of infection, both CD4 and CD8 T cells expressed IFN-gamma upon activation. Treatment with the caspase-8 inhibitor zIETD-fmk (benzyl-oxycarbonyl-Ile- Glu(OMe)-Thr-Asp(OMe)-fluoromethyl ketone) reduced the proportion of CD8 T cells and IFN-gamma expression in both CD4 and CD8 T cells. We conclude that a non apoptotic role of caspase-8 activity may be required for T cell-mediated type-1 responses during L. major infection.

  16. CD4+ T cells with an activated and exhausted phenotype distinguish immunodeficiency during aviremic HIV-2 infection

    PubMed Central

    Buggert, Marcus; Frederiksen, Juliet; Lund, Ole; Betts, Michael R.; Biague, Antonio; Nielsen, Morten; Tauriainen, Johanna; Norrgren, Hans; Medstrand, Patrik; Karlsson, Annika C.; Jansson, Marianne

    2016-01-01

    Objective: HIV type 2 (HIV-2) represents an attenuated form of HIV, in which many infected individuals remain ‘aviremic’ without antiretroviral therapy. However, aviremic HIV-2 disease progression exists, and in the current study, we therefore aimed to examine if specific pathological characteristics of CD4+ T cells are linked to such outcome. Design: HIV-seronegative (n = 25), HIV type 1 (HIV-1) (n = 33), HIV-2 (n = 39, of whom 26 were aviremic), and HIV-1/2 dually (HIV-D) (n = 13)-infected study participants were enrolled from an occupational cohort in Guinea-Bissau. Methods: CD4+ T-cell differentiation, activation, exhaustion, senescence, and transcription factors were assessed by polychromatic flow cytometry. Multidimensional clustering bioinformatic tools were used to identify CD4+ T-cell subpopulations linked to infection type and disease stage. Results: HIV-2-infected individuals had early and late-differentiated CD4+ T-cell clusters with lower activation (CD38+HLA-DR+) and exhaustion programmed death-1 (PD-1) than HIV-1 and HIV-D-infected individuals. We also noted that aviremic HIV-2-infected individuals possessed fewer individuals. CD4+ T cells with pathological signs compared to other HIV-infected groups. Still, compared to HIV-seronegative individuals, aviremic HIV-2-infected individuals had T-bet+ CD4+ T cells that showed elevated immune activation/exhaustion, and particularly the frequencies of PD-1+ cells were associated with a suboptimal percentage of CD4+ T cells. Conclusion: Increased frequencies of CD4+ T cells with an activated/exhausted phenotype correlate with exacerbated immunodeficiency in aviremic HIV-2-infected individuals. Thus, these findings encourage studies on the introduction of antiretroviral therapy also to individuals with aviremic HIV-2 infection. PMID:27525551

  17. Neisseria gonorrhoeae enhances HIV-1 infection of primary resting CD4+ T cells through TLR2 activation.

    PubMed

    Ding, Jian; Rapista, Aprille; Teleshova, Natalia; Mosoyan, Goar; Jarvis, Gary A; Klotman, Mary E; Chang, Theresa L

    2010-03-15

    Sexually transmitted infections increase the likelihood of HIV-1 transmission. We investigated the effect of Neisseria gonorrheae (gonococcus [GC]) exposure on HIV replication in primary resting CD4(+) T cells, a major HIV target cell during the early stage of sexual transmission of HIV. GC and TLR2 agonists, such as peptidylglycan (PGN), Pam(3)CSK(4), and Pam(3)C-Lip, a GC-derived synthetic lipopeptide, but not TLR4 agonists including LPS or GC lipooligosaccharide enhanced HIV-1 infection of primary resting CD4(+) T cells after viral entry. Pretreatment of CD4(+) cells with PGN also promoted HIV infection. Anti-TLR2 Abs abolished the HIV enhancing effect of GC and Pam(3)C-Lip, indicating that GC-mediated enhancement of HIV infection of resting CD4(+) T cells was through TLR2. IL-2 was required for TLR2-mediated HIV enhancement. PGN and GC induced cell surface expression of T cell activation markers and HIV coreceptors, CCR5 and CXCR4. The maximal postentry HIV enhancing effect was achieved when PGN was added immediately after viral exposure. Kinetic studies and analysis of HIV DNA products indicated that GC exposure and TLR2 activation enhanced HIV infection at the step of nuclear import. We conclude that GC enhanced HIV infection of primary resting CD4(+) T cells through TLR2 activation, which both increased the susceptibility of primary CD4(+) T cells to HIV infection as well as enhanced HIV-infected CD4(+) T cells at the early stage of HIV life cycle after entry. This study provides a molecular mechanism by which nonulcerative sexually transmitted infections mediate enhancement of HIV infection and has implication for HIV prevention and therapeutics. PMID:20147631

  18. Antigen-dependent and -independent contributions to primary memory CD8 T cell activation and protection following infection.

    PubMed

    Martin, Matthew D; Badovinac, Vladimir P

    2015-12-10

    Memory CD8 T-cell activation, including expression of IFN-γ and granzymeB, can be induced by antigen (Ag)-dependent signals through the T-cell-receptor, or by pathogen-derived inflammatory cytokines in an Ag-independent manner. Recent studies have come to conflicting results regarding the contributions of Ag and/or inflammation to memory CD8 T-cell activation. Additionally, research has indicated that inflammation-driven CD8 T-cell responses during un-related infections (bystander activation) have the potential to provide protection, but whether protection occurs in immuno-competent hosts is unclear. To investigate these questions, we examined activation of virus-specific memory CD8 T-cells following infection with L. monocytogenes either expressing or not cognate Ag. We show that Ag and inflammation act synergistically in vitro to induce memory activation. In vivo, we found that when memory CD8 T-cells significantly contribute to clearance of infection, early activation and continued responses by these cells are enhanced by cognate Ag recognition. Mechanistically, we show that bystander responses by memory are dependent upon the dose of infection and the amount of inflammation elicited following infection and are able to provide protection in IFN-γ deficient mice, but not in immuno-competent hosts. The data elucidate the requirements for memory CD8 T-cell activation and the protective role of bystander responses.

  19. Antigen-dependent and –independent contributions to primary memory CD8 T cell activation and protection following infection

    PubMed Central

    Martin, Matthew D.; Badovinac, Vladimir P.

    2015-01-01

    Memory CD8 T-cell activation, including expression of IFN-γ and granzymeB, can be induced by antigen (Ag)-dependent signals through the T-cell-receptor, or by pathogen-derived inflammatory cytokines in an Ag-independent manner. Recent studies have come to conflicting results regarding the contributions of Ag and/or inflammation to memory CD8 T-cell activation. Additionally, research has indicated that inflammation-driven CD8 T-cell responses during un-related infections (bystander activation) have the potential to provide protection, but whether protection occurs in immuno-competent hosts is unclear. To investigate these questions, we examined activation of virus-specific memory CD8 T-cells following infection with L. monocytogenes either expressing or not cognate Ag. We show that Ag and inflammation act synergistically in vitro to induce memory activation. In vivo, we found that when memory CD8 T-cells significantly contribute to clearance of infection, early activation and continued responses by these cells are enhanced by cognate Ag recognition. Mechanistically, we show that bystander responses by memory are dependent upon the dose of infection and the amount of inflammation elicited following infection and are able to provide protection in IFN-γ deficient mice, but not in immuno-competent hosts. The data elucidate the requirements for memory CD8 T-cell activation and the protective role of bystander responses. PMID:26658291

  20. Dengue Virus Infection-Enhancing Activity in Serum Samples with Neutralizing Activity as Determined by Using FcγR-Expressing Cells

    PubMed Central

    Moi, Meng Ling; Lim, Chang-Kweng; Chua, Kaw Bing; Takasaki, Tomohiko; Kurane, Ichiro

    2012-01-01

    Background Progress in dengue vaccine development has been hampered by limited understanding of protective immunity against dengue virus infection. Conventional neutralizing antibody titration assays that use FcγR-negative cells do not consider possible infection-enhancement activity. We reasoned that as FcγR-expressing cells are the major target cells of dengue virus, neutralizing antibody titration assays using FcγR-expressing cells that determine the sum of neutralizing and infection-enhancing activity, may better reflect the biological properties of antibodies in vivo. Methods and Findings We evaluated serum samples from 80 residents of a dengue endemic country, Malaysia, for neutralizing activity, and infection-enhancing activity at 1∶10 serum dilution by using FcγR-negative BHK cells and FcγR-expressing BHK cells. The serum samples consisted of a panel of patients with acute DENV infection (31%, 25/80) and a panel of donors without acute DENV infection (69%, 55/80). A high proportion of the tested serum samples (75%, 60/80) demonstrated DENV neutralizing activity (PRNT50≥10) and infection-enhancing activity. Eleven of 18 serum samples from patients with acute secondary DENV infection demonstrated neutralizing activity to the infecting serotype determined by using FcγR-negative BHK cells (PRNT50≥10), but not when determined by using FcγR-expressing cells. Conclusion Human serum samples with low neutralizing activity determined by using FcγR-negative cells showed DENV infection-enhancing activity using FcγR-expressing cells, whereas those with high neutralizing activity determined by using FcγR-negative cells demonstrate low or no infection-enhancing activity using FcγR-expressing cells. The results suggest an inverse relationship between neutralizing antibody titer and infection-enhancing activity, and that neutralizing activity determined by using FcγR-expressing cells, and not the activity determined by using FcγR-negative cells, may

  1. Suppression of NYVAC Infection in HeLa Cells Requires RNase L but Is Independent of Protein Kinase R Activity.

    PubMed

    Fernández-Escobar, Mercedes; Nájera, José Luis; Baldanta, Sara; Rodriguez, Dolores; Way, Michael; Esteban, Mariano; Guerra, Susana

    2015-12-09

    Protein kinase R (PKR) and RNase L are host cell components that function to contain viral spread after infections. In this study, we analyzed the role of both proteins in the abortive infection of human HeLa cells with the poxvirus strain NYVAC, for which an inhibition of viral A27L and B5R gene expression is described. Specifically, the translation of these viral genes is independent of PKR activation, but their expression is dependent on the RNase L activity.

  2. Infection of vascular endothelial cells with herpes simplex virus enhances tissue factor activity and reduces thrombomodulin expression.

    PubMed Central

    Key, N S; Vercellotti, G M; Winkelmann, J C; Moldow, C F; Goodman, J L; Esmon, N L; Esmon, C T; Jacob, H S

    1990-01-01

    Latent infection of vascular cells with herpes-viruses may play a pathogenic role in the development of human atherosclerosis. In a previous study, we found that cultured human umbilical vein endothelial cells (HUVECs) infected with herpes simplex virus 1 (HSV-1) became procoagulant, exemplified both by their enhanced assembly of the prothrombinase complex and by their inability to reduce adhesion of platelets. We now report two further procoagulant consequences of endothelial HSV infection: loss of surface thrombomodulin (TM) activity and induction of synthesis of tissue factor. Within 4 hr of infection of HUVECs, TM activity measured by thrombin-dependent protein C activation declined 21 +/- 3% (P less than 0.05) and by 18 hr, 48 +/- 5% (P less than 0.001). Similar significant TM decrements accompanied infection of bovine aortic endothelial cells. Identical TM loss was induced with HSV-2 infection but not with adenovirus infection. Decreased surface expression of TM antigen (measured by the specific binding of a polyclonal antibody to bovine TM) closely paralleled the loss of TM activity. As examined by Northern blotting, these losses apparently reflected rapid onset (within 4 hr of HSV infection) loss of mRNA for TM. In contrast, HSV infection induced a viral-dose-dependent increase in synthesis of tissue factor protein, adding to the procoagulant state. The results indicate that loss of endothelial protein-synthetic capacity is not a universal effect of HSV infection. We suggest that the procoagulant state induced by reduction in TM activity and amplified tissue factor activity accompanying HSV infection of endothelium could contribute to deposition of thrombi on atherosclerotic plaques and to the "coagulant-necrosis" state that characterizes HSV-infected mucocutaneous lesions. Images PMID:2169619

  3. Bovine viral diarrhea virus 2 infection activates the unfolded protein response in MDBK cells, leading to apoptosis.

    PubMed

    Maeda, Kouji; Fujihara, Masatoshi; Harasawa, Ryô

    2009-06-01

    Bovine viral diarrhea virus 2 (BVDV-2) strains are divided into cytopathic and non-cytopathic biotypes based on the ablity to induce cytopathic effects in cultured cells. The mechanism of cytopathogenicity of BVDV-2 is not well understood. We examined cytopathogenesis in MDBK cells resulting from BVDV-2 infections by microscopic examinations and microarray analysis. We found that BVDV-2 activates endoplasmic reticulum (ER) stress signaling pathways that contribute to apoptosis of infected cells. We also monitored the expression of ER stress marker gene by RT-PCR during BVDV-2 infection and demonstrated that infection of MDBK cells with a cytopathic strain of BVDV-2 induces glucose-regulated protein 78 expression. Infection with BVDV-2 also induces DNA-damage-inducible transcript 3 expression and downregulates the lectin-galactoside-binding soluble 1 level. These results show that cytopathic strains of BVDV-2 induce an ER stress response resulting in apoptosis.

  4. Stress responses in flavivirus-infected cells: activation of unfolded protein response and autophagy

    PubMed Central

    Blázquez, Ana-Belén; Escribano-Romero, Estela; Merino-Ramos, Teresa; Saiz, Juan-Carlos; Martín-Acebes, Miguel A.

    2014-01-01

    The Flavivirus is a genus of RNA viruses that includes multiple long known human, animal, and zoonotic pathogens such as Dengue virus, yellow fever virus, West Nile virus, or Japanese encephalitis virus, as well as other less known viruses that represent potential threats for human and animal health such as Usutu or Zika viruses. Flavivirus replication is based on endoplasmic reticulum-derived structures. Membrane remodeling and accumulation of viral factors induce endoplasmic reticulum stress that results in activation of a cellular signaling response termed unfolded protein response (UPR), which can be modulated by the viruses for their own benefit. Concomitant with the activation of the UPR, an upregulation of the autophagic pathway in cells infected with different flaviviruses has also been described. This review addresses the current knowledge of the relationship between endoplasmic reticulum stress, UPR, and autophagy in flavivirus-infected cells and the growing evidences for an involvement of these cellular pathways in the replication and pathogenesis of these viruses. PMID:24917859

  5. Activation of peripheral blood mononuclear cells by dengue virus infection depotentiates balapiravir.

    PubMed

    Chen, Yen-Liang; Abdul Ghafar, Nahdiyah; Karuna, Ratna; Fu, Yilong; Lim, Siew Pheng; Schul, Wouter; Gu, Feng; Herve, Maxime; Yokohama, Fumiaki; Wang, Gang; Cerny, Daniela; Fink, Katja; Blasco, Francesca; Shi, Pei-Yong

    2014-02-01

    In a recent clinical trial, balapiravir, a prodrug of a cytidine analog (R1479), failed to achieve efficacy (reducing viremia after treatment) in dengue patients, although the plasma trough concentration of R1479 remained above the 50% effective concentration (EC(50)). Here, we report experimental evidence to explain the discrepancy between the in vitro and in vivo results and its implication for drug development. R1479 lost its potency by 125-fold when balapiravir was used to treat primary human peripheral blood mononuclear cells (PBMCs; one of the major cells targeted for viral replication) that were preinfected with dengue virus. The elevated EC(50) was greater than the plasma trough concentration of R1479 observed in dengue patients treated with balapiravir and could possibly explain the efficacy failure. Mechanistically, dengue virus infection triggered PBMCs to generate cytokines, which decreased their efficiency of conversion of R1479 to its triphosphate form (the active antiviral ingredient), resulting in decreased antiviral potency. In contrast to the cytidine-based compound R1479, the potency of an adenosine-based inhibitor of dengue virus (NITD008) was much less affected. Taken together, our results demonstrate that viral infection in patients before treatment could significantly affect the conversion of the prodrug to its active form; such an effect should be calculated when estimating the dose efficacious for humans.

  6. Gut Dendritic Cell Activation Links an Altered Colonic Microbiome to Mucosal and Systemic T Cell Activation in Untreated HIV-1 infection

    PubMed Central

    Dillon, SM; Lee, EJ; Kotter, CV; Austin, GL; Gianella, S; Siewe, B; Smith, DM; Landay, AL; McManus, MC; Robertson, CE; Frank, DN; McCarter, MD; Wilson, CC

    2015-01-01

    HIV-1-associated disruption of intestinal homeostasis is a major factor contributing to chronic immune activation and inflammation. Dendritic cells (DCs) are crucial in maintaining intestinal homeostasis, but the impact of HIV-1 infection on intestinal DC number and function has not been extensively studied. We compared the frequency and activation/maturation status of colonic myeloid DC (mDC) subsets (CD1c+ and CD1cneg) and plasmacytoid DCs in untreated HIV-1-infected subjects with uninfected controls. Colonic mDCs in HIV-1-infected subjects had increased CD40 but decreased CD83 expression, and CD40 expression on CD1c+ mDCs positively correlated with mucosal HIV-1 viral load, with mucosal and systemic cytokine production, and with frequencies of activated colon and blood T cells. Percent of CD83+CD1c+ mDCs negatively correlated with frequencies of IFN-γ-producing colon CD4+ and CD8+ T cells. CD40 expression on CD1c+ mDCs positively associated with abundance of high prevalence mucosal Prevotella copri and P. stercorea, but negatively associated with a number of low prevalence mucosal species including Rumminococcus bromii. CD1c+ mDC cytokine production was greater in response to in vitro stimulation with Prevotella species relative to R. bromii. These findings suggest that during HIV infection, colonic mDCs become activated upon exposure to mucosal pathobiont bacteria leading to mucosal and systemic immune activation. PMID:25921339

  7. Prostate tumor cells infected with a recombinant influenza virus expressing a truncated NS1 protein activate cytolytic CD8+ cells to recognize noninfected tumor cells.

    PubMed

    Efferson, Clay L; Tsuda, Naotake; Kawano, Kouichiro; Nistal-Villán, Estanislao; Sellappan, Shankhar; Yu, Dihua; Murray, James L; García-Sastre, Adolfo; Ioannides, Constantin G

    2006-01-01

    Many viral oncolytic approaches against cancer are based on the ability of specific viruses to replicate in tumors expressing components of the constitutively activated Ras/mitogen-activated protein kinase (MAPK) pathways and/or inhibited or dysregulated alpha/beta interferon (IFN-alpha/beta) response pathways. A major issue when considering these approaches is their applicability to tumors that lack activated Ras. To identify the effector mechanisms activated by oncolytic viruses, we investigated inhibition of proliferation of the prostate cancer line LNCap by the recombinant TR-NS1 influenza A virus, a genetically attenuated influenza A/PR8/34 virus expressing a truncated nonstructural protein (NS1) of 126 amino acids. LNCap cells lack constitutively activated MAPK, extracellular signal-regulated kinase (ERK), and p38 and are resistant to death by IFN-alpha. Truncation of the NS1 protein of influenza viruses is known to result in viral attenuation due to a reduced ability of the NS1 to inhibit the IFN-alpha/beta response. Infection with TR-NS1 virus rapidly activated ERK-1 more than ERK-2 in LNCap cells. Importantly, TR-NS1 virus infection transiently inhibited cell proliferation and induced apoptosis in LNCap cells. Addition of peripheral blood mononuclear cells (PBMC) and interleukin 12 (IL-12) to TR-NS1 virus-infected LNCap cells (TR-NS1-LNCap) resulted in faster elimination of TR-NS1-LNCap cells compared with LNCap cells. Moreover, TR-NS1-LNCap cells induced IFN-gamma in PBMC. The levels of IFN-gamma were amplified by IL-12. TR-NS1-LNCap cells also induced tumor-lytic cytotoxic T lymphocytes (CTL). These CTL lysed noninfected LNCap cells in a CD8-dependent manner. Activation of cellular immunity to tumor cells by viruses is an intriguing effector pathway, which should be especially significant for elimination of human tumors that lack activated Ras.

  8. Infection-induced type I interferons activate CD11b on B-1 cells for subsequent lymph node accumulation

    PubMed Central

    Waffarn, Elizabeth E.; Hastey, Christine J.; Dixit, Neha; Choi, Youn Soo; Cherry, Simon; Kalinke, Ulrich; Simon, Scott I.; Baumgarth, Nicole

    2016-01-01

    Innate-like B-1a lymphocytes rapidly redistribute to regional mediastinal lymph nodes (MedLN) during influenza infection to generate protective IgM. Here we demonstrate that influenza infection-induced type I interferons directly stimulate body cavity B-1 cells and are a necessary signal required for B-1 cell accumulation in MedLN. Vascular mimetic flow chamber studies show that type I interferons increase ligand-mediated B-1 cell adhesion under shear stress by inducing high-affinity conformation shifts of surface-expressed integrins. In vivo trafficking experiments identify CD11b as the non-redundant, interferon-activated integrin required for B-1 cell accumulation in MedLN. Thus CD11b on B-1 cells senses infection-induced innate signals and facilitates their rapid sequester into secondary lymphoid tissues, thereby regulating the accumulation of polyreactive IgM producers at sites of infection. PMID:26612263

  9. Endothelial cell permeability during hantavirus infection involves factor XII-dependent increased activation of the kallikrein-kinin system.

    PubMed

    Taylor, Shannon L; Wahl-Jensen, Victoria; Copeland, Anna Maria; Jahrling, Peter B; Schmaljohn, Connie S

    2013-01-01

    Hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS) are diseases caused by hantavirus infections and are characterized by vascular leakage due to alterations of the endothelial barrier. Hantavirus-infected endothelial cells (EC) display no overt cytopathology; consequently, pathogenesis models have focused either on the influx of immune cells and release of cytokines or on increased degradation of the adherens junction protein, vascular endothelial (VE)-cadherin, due to hantavirus-mediated hypersensitization of EC to vascular endothelial growth factor (VEGF). To examine endothelial leakage in a relevant in vitro system, we co-cultured endothelial and vascular smooth muscle cells (vSMC) to generate capillary blood vessel-like structures. In contrast to results obtained in monolayers of cultured EC, we found that despite viral replication in both cell types as well as the presence of VEGF, infected in vitro vessels neither lost integrity nor displayed evidence of VE-cadherin degradation. Here, we present evidence for a novel mechanism of hantavirus-induced vascular leakage involving activation of the plasma kallikrein-kinin system (KKS). We show that incubation of factor XII (FXII), prekallikrein (PK), and high molecular weight kininogen (HK) plasma proteins with hantavirus-infected EC results in increased cleavage of HK, higher enzymatic activities of FXIIa/kallikrein (KAL) and increased liberation of bradykinin (BK). Measuring cell permeability in real-time using electric cell-substrate impedance sensing (ECIS), we identified dramatic increases in endothelial cell permeability after KKS activation and liberation of BK. Furthermore, the alterations in permeability could be prevented using inhibitors that directly block BK binding, the activity of FXIIa, or the activity of KAL. Lastly, FXII binding and autoactivation is increased on the surface of hantavirus-infected EC. These data are the first to demonstrate KKS activation during

  10. Involvement of fish signal transducer and activator of transcription 3 (STAT3) in nodavirus infection induced cell death.

    PubMed

    Huang, Youhua; Huang, Xiaohong; Yang, Ying; Wang, Wei; Yu, Yepin; Qin, Qiwei

    2015-03-01

    The Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway is an important signaling pathway activated by interferons in response to virus infection. Fish STAT3 has been demonstrated to be involved in Singapore grouper iridovirus (SGIV) infection and virus induced paraptosis, but its effects on the replication of other fish viruses still remained uncertain. Here, the roles of grouper STAT3 (Ec-STAT3) in red spotted grouper nervous necrosis virus (RGNNV) infection were investigated. The present data showed that the distribution of phosphorylated Ec-STAT3 was altered in RGNNV infected fish cells, and the promoter activity of STAT3 was significantly increased during virus infection, suggesting that STAT3 activation was involved in RGNNV infection. Using STAT3 specific inhibitor, we found that inhibition of Ec-STAT3 in vitro did not affect the transcription and protein synthesis of RGNNV coat protein (CP), however, the severity of RGNNV induced vacuolation and autophagy was significantly increased. Meanwhile, at the late stage of virus infection, RGNNV induced necrotic cell death was significantly decreased after inhibition of Ec-STAT3. Further studies indicated that Ec-STAT3 inhibition significantly increased the transcript level of autophagy related genes, including UNC-51-like kinase 2 (ULK2) and microtubule-associated protein 1 light chain 3-II (LC3-II) induced by RGNNV infection. Moreover, the expression of several pro-inflammatory factors, including TNFα, IL-1β and IL-8 were mediated by Ec-STAT3 during RGNNV infection. Together, our results not only firstly revealed that STAT3 exerted novel roles in response to fish virus infection, but also provided new insights into understanding the roles of STAT3 in different forms of programmed cell death. PMID:25555814

  11. Involvement of fish signal transducer and activator of transcription 3 (STAT3) in nodavirus infection induced cell death.

    PubMed

    Huang, Youhua; Huang, Xiaohong; Yang, Ying; Wang, Wei; Yu, Yepin; Qin, Qiwei

    2015-03-01

    The Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway is an important signaling pathway activated by interferons in response to virus infection. Fish STAT3 has been demonstrated to be involved in Singapore grouper iridovirus (SGIV) infection and virus induced paraptosis, but its effects on the replication of other fish viruses still remained uncertain. Here, the roles of grouper STAT3 (Ec-STAT3) in red spotted grouper nervous necrosis virus (RGNNV) infection were investigated. The present data showed that the distribution of phosphorylated Ec-STAT3 was altered in RGNNV infected fish cells, and the promoter activity of STAT3 was significantly increased during virus infection, suggesting that STAT3 activation was involved in RGNNV infection. Using STAT3 specific inhibitor, we found that inhibition of Ec-STAT3 in vitro did not affect the transcription and protein synthesis of RGNNV coat protein (CP), however, the severity of RGNNV induced vacuolation and autophagy was significantly increased. Meanwhile, at the late stage of virus infection, RGNNV induced necrotic cell death was significantly decreased after inhibition of Ec-STAT3. Further studies indicated that Ec-STAT3 inhibition significantly increased the transcript level of autophagy related genes, including UNC-51-like kinase 2 (ULK2) and microtubule-associated protein 1 light chain 3-II (LC3-II) induced by RGNNV infection. Moreover, the expression of several pro-inflammatory factors, including TNFα, IL-1β and IL-8 were mediated by Ec-STAT3 during RGNNV infection. Together, our results not only firstly revealed that STAT3 exerted novel roles in response to fish virus infection, but also provided new insights into understanding the roles of STAT3 in different forms of programmed cell death.

  12. Provirus activation plus CD59 blockage triggers antibody-dependent complement-mediated lysis of latently HIV-1-infected cells.

    PubMed

    Lan, Jie; Yang, Kai; Byrd, Daniel; Hu, Ningjie; Amet, Tohti; Shepherd, Nicole; Desai, Mona; Gao, Jimin; Gupta, Samir; Sun, Yongtao; Yu, Qigui

    2014-10-01

    Latently HIV-1-infected cells are recognized as the last barrier toward viral eradication and cure. To purge these cells, we combined a provirus stimulant with a blocker of human CD59, a key member of the regulators of complement activation, to trigger Ab-dependent complement-mediated lysis. Provirus stimulants including prostratin and histone deacetylase inhibitors such as romidepsin and suberoylanilide hydroxamic acid activated proviruses in the latently HIV-1-infected T cell line ACH-2 as virion production and viral protein expression on the cell surface were induced. Romidepsin was the most attractive provirus stimulant as it effectively activated proviruses at nanomolar concentrations that can be achieved clinically. Antiretroviral drugs including two protease inhibitors (atazanavir and darunavir) and an RT inhibitor (emtricitabine) did not affect the activity of provirus stimulants in the activation of proviruses. However, saquinavir (a protease inhibitor) markedly suppressed virus production, although it did not affect the percentage of cells expressing viral Env on the cell surface. Provirus-activated ACH-2 cells expressed HIV-1 Env that colocalized with CD59 in lipid rafts on the cell surface, facilitating direct interaction between them. Blockage of CD59 rendered provirus-activated ACH-2 cells and primary human CD4(+) T cells that were latently infected with HIV-1 sensitive to Ab-dependent complement-mediated lysis by anti-HIV-1 polyclonal Abs or plasma from HIV-1-infected patients. Therefore, a combination of provirus stimulants with regulators of complement activation blockers represents a novel approach to eliminate HIV-1.

  13. Normal T-Cell Turnover in Sooty Mangabeys Harboring Active Simian Immunodeficiency Virus Infection

    PubMed Central

    Chakrabarti, Lisa A.; Lewin, Sharon R.; Zhang, Linqi; Gettie, Agegnehu; Luckay, Amara; Martin, Louis N.; Skulsky, Eva; Ho, David D.; Cheng-Mayer, Cecilia; Marx, Preston A.

    2000-01-01

    Sooty mangabeys naturally infected with simian immunodeficiency virus (SIV) remain healthy though they harbor viral loads comparable to those in rhesus macaques that progress to AIDS. To assess the immunologic basis of disease resistance in mangabeys, we compared the effect of SIV infection on T-cell regeneration in both monkey species. Measurement of the proliferation marker Ki-67 by flow cytometry showed that mangabeys harbored proliferating T cells at a level of 3 to 4% in peripheral blood irrespective of their infection status. In contrast, rhesus macaques demonstrated a naturally high fraction of proliferating T cells (7%) that increased two- to threefold following SIV infection. Ki-67+ T cells were predominantly CD45RA−, indicating increased proliferation of memory cells in macaques. Quantitation of an episomal DNA product of T-cell receptor α rearrangement (termed α1 circle) showed that the concentration of recent thymic emigrants in blood decreased with age over a 2-log unit range in both monkey species, consistent with age-related thymic involution. SIV infection caused a limited decrease of α1 circle numbers in mangabeys as well as in macaques. Dilution of α1 circles by T-cell proliferation likely contributed to this decrease, since α1 circle numbers and Ki-67+ fractions correlated negatively. These findings are compatible with immune exhaustion mediated by abnormal T-cell proliferation, rather than with early thymic failure, in SIV-infected macaques. Normal T-cell turnover in SIV-infected mangabeys provides an explanation for the long-term maintenance of a functional immune system in these hosts. PMID:10627531

  14. Control of Viremia Enables Acquisition of Resting Memory B Cells with Age and Normalization of Activated B Cell Phenotypes in HIV-Infected Children

    PubMed Central

    Muema, Daniel M.; Macharia, Gladys N.; Hassan, Amin S.; Mwaringa, Shalton M.; Fegan, Greg W.; Berkley, James A.; Urban, Britta C.

    2015-01-01

    HIV affects the function of all lymphocyte populations, including B cells. Phenotypic and functional defects of B cells in HIV-infected adults have been well characterized, but defects in children have not been studied to the same extent. We determined the proportion of B cell subsets and frequencies of Ag-specific memory B cells in peripheral blood from HIV-infected children and healthy controls, using flow cytometry and B cell ELISPOT, respectively. In addition, we measured the quantities and avidities of plasma Abs against various Ags by ELISA. We also determined plasma levels of BAFF and expression of BAFF receptors on B cells. Children with high HIV viremia had increased proportions of activated mature B cells, tissue-like memory B cells and plasmablasts, and low proportions of naive B cells when compared with community controls and children with low HIV viremia, similar to adults infected with HIV. HIV-infected groups had lower proportions of resting memory B cells than did community controls. Notably, high HIV viremia prevented the age-dependent accumulation of class-switched resting memory B cells. HIV-infected children, regardless of the level of viremia, showed lower quantities and avidities of IgG and lower frequencies of memory B cells against Expanded Program on Immunization vaccines. The HIV-infected children had an altered BAFF profile that could have affected their B cell compartment. Therefore, B cell defects in HIV-infected children are similar to those seen in HIV-infected adults. However, control of HIV viremia is associated with normalization of activated B cell subsets and allows age-dependent accumulation of resting memory B cells. PMID:26116511

  15. Control of Viremia Enables Acquisition of Resting Memory B Cells with Age and Normalization of Activated B Cell Phenotypes in HIV-Infected Children.

    PubMed

    Muema, Daniel M; Macharia, Gladys N; Hassan, Amin S; Mwaringa, Shalton M; Fegan, Greg W; Berkley, James A; Nduati, Eunice W; Urban, Britta C

    2015-08-01

    HIV affects the function of all lymphocyte populations, including B cells. Phenotypic and functional defects of B cells in HIV-infected adults have been well characterized, but defects in children have not been studied to the same extent. We determined the proportion of B cell subsets and frequencies of Ag-specific memory B cells in peripheral blood from HIV-infected children and healthy controls, using flow cytometry and B cell ELISPOT, respectively. In addition, we measured the quantities and avidities of plasma Abs against various Ags by ELISA. We also determined plasma levels of BAFF and expression of BAFF receptors on B cells. Children with high HIV viremia had increased proportions of activated mature B cells, tissue-like memory B cells and plasmablasts, and low proportions of naive B cells when compared with community controls and children with low HIV viremia, similar to adults infected with HIV. HIV-infected groups had lower proportions of resting memory B cells than did community controls. Notably, high HIV viremia prevented the age-dependent accumulation of class-switched resting memory B cells. HIV-infected children, regardless of the level of viremia, showed lower quantities and avidities of IgG and lower frequencies of memory B cells against Expanded Program on Immunization vaccines. The HIV-infected children had an altered BAFF profile that could have affected their B cell compartment. Therefore, B cell defects in HIV-infected children are similar to those seen in HIV-infected adults. However, control of HIV viremia is associated with normalization of activated B cell subsets and allows age-dependent accumulation of resting memory B cells.

  16. Enhanced Follicular Dendritic Cell-B Cell Interaction in HIV and SIV Infections and its Potential Role in Polyclonal B Cell Activation

    PubMed Central

    Lewis, Mark. G.; Kosco-Vilbois, Marie H.

    1998-01-01

    Human immunodeficiency virus (HIV) infections have been characterized by both polyclonal Bcell activation and enhanced responsiveness to B-cell growth factors on one hand and the loss of specific antibody (Ab) responses and refractoriness to the normal signals for B-cell activation on the other. Histopathological studies of lymph node from HIV- and simian immunodeficiency virus (SIV)-infected individuals have indicated initial follicular hyperplasia and the appearance of large irregular germinal centers that undergo progressive involution concomitant with follicular dendritic-cell (FDC) disruption. During this process, follicular dendritic-cell -enriched lymph-node-cell cultures exhibit increased ability to induce cluster formation (“in vitro germinal centers”), lymphocyte proliferation and antibody production compared to uninfected controls. This paper discusses how enhanced FDC-B-cell interaction within SIV-infected germinal centers may result in a reduced ability to select high-affinity B cells and alter the dynamics of antibodyproducing- cell and memory-cell generation resulting in the observed hyperactivity. PMID:9716906

  17. Preserved dendritic cell HLA-DR expression and reduced regulatory T cell activation in asymptomatic Plasmodium falciparum and P. vivax infection.

    PubMed

    Kho, Steven; Marfurt, Jutta; Noviyanti, Rintis; Kusuma, Andreas; Piera, Kim A; Burdam, Faustina H; Kenangalem, Enny; Lampah, Daniel A; Engwerda, Christian R; Poespoprodjo, Jeanne R; Price, Ric N; Anstey, Nicholas M; Minigo, Gabriela; Woodberry, Tonia

    2015-08-01

    Clinical illness with Plasmodium falciparum or Plasmodium vivax compromises the function of dendritic cells (DC) and expands regulatory T (Treg) cells. Individuals with asymptomatic parasitemia have clinical immunity, restricting parasite expansion and preventing clinical disease. The role of DC and Treg cells during asymptomatic Plasmodium infection is unclear. During a cross-sectional household survey in Papua, Indonesia, we examined the number and activation of blood plasmacytoid DC (pDC), CD141(+), and CD1c(+) myeloid DC (mDC) subsets and Treg cells using flow cytometry in 168 afebrile children (of whom 15 had P. falciparum and 36 had P. vivax infections) and 162 afebrile adults (of whom 20 had P. falciparum and 20 had P. vivax infections), alongside samples from 16 patients hospitalized with uncomplicated malaria. Unlike DC from malaria patients, DC from children and adults with asymptomatic, microscopy-positive P. vivax or P. falciparum infection increased or retained HLA-DR expression. Treg cells in asymptomatic adults and children exhibited reduced activation, suggesting increased immune responsiveness. The pDC and mDC subsets varied according to clinical immunity (asymptomatic or symptomatic Plasmodium infection) and, in asymptomatic infection, according to host age and parasite species. In conclusion, active control of asymptomatic infection was associated with and likely contingent upon functional DC and reduced Treg cell activation.

  18. Long-term kinetics of T cell production in HIV-infected subjects treated with highly active antiretroviral therapy

    PubMed Central

    Fleury, S.; Rizzardi, G. P.; Chapuis, A.; Tambussi, G.; Knabenhans, C.; Simeoni, E.; Meuwly, J.-Y.; Corpataux, J.-M.; Lazzarin, A.; Miedema, F.; Pantaleo, G.

    2000-01-01

    The long-term kinetics of T cell production following highly active antiretroviral therapy (HAART) were investigated in blood and lymph node in a group of HIV-infected subjects at early stage of established infection and prospectively studied for 72 wk. Before HAART, CD4 and CD8 T cell turnover was increased. However, the total number of proliferating CD4+ T lymphocytes, i.e., CD4+Ki67+ T lymphocytes, was not significantly different in HIV-infected (n = 73) and HIV-negative (n = 15) subjects, whereas proliferating CD8+Ki67+ T lymphocytes were significantly higher in HIV-infected subjects. After HAART, the total body number of proliferating CD4+Ki67+ T lymphocytes increased over time and was associated with an increase of both naive and memory CD4+ T cells. The maximal increase (2-fold) was observed at week 36, whereas at week 72 the number of proliferating CD4+ T cells dropped to baseline levels, i.e., before HAART. The kinetics of the fraction of proliferating CD4 and CD8 T cells were significantly correlated with the changes in the total body number of these T cell subsets. These results demonstrate a direct relationship between ex vivo measures of T cell production and quantitative changes in total body T lymphocyte populations. This study provides advances in the delineation of the kinetics of T cell production in HIV infection in the presence and/or in the absence of HAART. PMID:10805798

  19. Lymphoid cells in the spleens of woodchuck hepatitis virus-infected woodchucks are a site of active viral replication.

    PubMed Central

    Korba, B E; Wells, F; Tennant, B C; Cote, P J; Gerin, J L

    1987-01-01

    Lymphoid cells were purified from the spleens of 15 woodchucks and examined for the presence of woodchuck hepatitis virus (WHV). Lymphoid cells from the spleens of eight of eight chronically infected animals contained high levels of WHV RNA and DNA. A 100-fold lower level of WHV DNA was found in the spleen from one of five animals that had recovered from acute WHV infections 2 years before this analysis. No WHV nucleic acids were observed in either of two uninfected animals. WHV DNA patterns in the lymphoid cells from the spleens of the chronically infected animals, which included the presence of single-stranded DNA and RNA-DNA hybrid molecules, were identical to those observed in WHV-infected liver. WHV DNA in these cells was present in intact, 27-nm core particles which also contained the endogenous DNA polymerase activity. These results indicate that the spleen is a site of active WHV DNA replication and is most likely a major source of WHV-infected cells in the circulating lymphoid cell population. Images PMID:3573141

  20. Caspase-8 activity is part of the BeWo trophoblast cell defense mechanisms against Trypanosoma cruzi infection.

    PubMed

    Carrillo, Ileana; Droguett, Daniel; Castillo, Christian; Liempi, Ana; Muñoz, Lorena; Maya, Juan Diego; Galanti, Norbel; Kemmerling, Ulrike

    2016-09-01

    Congenital Chagas disease is caused by the protozoan parasite Trypanosoma cruzi that must cross the placental barrier during transmission. The trophoblast constitutes the first tissue in contact with the maternal-blood circulating parasite. Importantly, the congenital transmission rates are low, suggesting the presence of local placental defense mechanisms. Cellular proliferation and differentiation as well as apoptotic cell death are induced by the parasite and constitute part of the epithelial turnover of the trophoblast, which has been suggested to be part of those placental defenses. On the other hand, caspase-8 is an essential molecule in the modulation of trophoblast turnover by apoptosis and by epithelial differentiation. As an approach to study whether T. cruzi induced trophoblast turnover and infection is mediated by caspase-8, we infected BeWo cells (a trophoblastic cell line) with the parasite and determined in the infected cells the expression and enzymatic activity of caspase-8, DNA synthesis (as proliferation marker), β-human chorionic gonadotropin (β-hCG) (as differentiation marker) and activity of Caspase-3 (as apoptotic death marker). Parasite load in BeWo cells was measured by DNA quantification using qPCR and cell counting. Our results show that T. cruzi induces caspase-8 activity and that its inhibition increases trophoblast cells infection while decreases parasite induced cellular differentiation and apoptotic cell death, but not cellular proliferation. Thus, caspase-8 activity is part of the BeWo trophoblast cell defense mechanisms against T. cruzi infection. Together with our previous results, we suggest that the trophoblast turnover is part of local placental anti-parasite mechanisms.

  1. Comparative analysis of signature genes in porcine reproductive and respiratory syndrome virus (PRRSV)-infected porcine monocyte-derived dendritic cells at differential activation statuses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Activation statuses of monocytic cells, e.g. monocytes, macrophages and dendritic cells (DCs), are critically important for antiviral immunity. In particular, some devastating viruses, including porcine reproductive and respiratory syndrome virus (PRRSV), are capable of directly infecting these cell...

  2. Dysfunctional B-cell activation in cirrhosis due to hepatitis C infection associated with disappearance of CD27+ B-cell population

    PubMed Central

    Doi, Hiroyoshi; Iyer, Tara K.; Carpenter, Erica; Li, Hong; Chang, Kyong-Mi; Vonderheide, Robert H.; Kaplan, David E.

    2011-01-01

    Background Chronic hepatitis C virus infection is a leading cause of cirrhosis and hepatocellular carcinoma. Both advanced solid tumors and hepatitis C have previously been associated with memory B-cell dysfunction. In this study we sought to dissect the impact of viral infection, cirrhosis and liver cancer on memory B-cell frequency and function in the spectrum of HCV disease. Methods Peripheral blood from healthy donors, HCV-infected patients with F1–F2 liver fibrosis, HCV-infected patients with cirrhosis, patients with HCV-related hepatocellular carcinoma and non-HCV-infected cirrhotics were assessed for B-cell phenotype by flow cytometry. Isolated B-cells were stimulated with anti-CD40 antibodies and TLR9 agonist for assessment of costimulation marker expression, cytokine production, immunoglobulin production and CD4+ T-cell allostimulatory capacity. Results CD27+ memory B-cells, and more specifically CD27+IgM+ B-cells, were markedly less frequent in cirrhotic patients independent of HCV infection. Circulating B-cells in cirrhotics were hyporesponsive to CD40/TLR9 activation as characterized by CD70 upregulation, TNFβ secretion, IgG production and T-cell allostimulation. Lastly, blockade of TLR4 and TLR9 signaling abrogated the activation of normal donor B-cells by cirrhotic plasma suggesting a role for bacterial translocation in driving B-cell changes in cirrhosis. Conclusion Profound abnormalities in B-cell phenotype and function occur in cirrhosis independent of hepatitis C viral infection. These B-cell defects may explain in part the vaccine hyporesponsiveness and susceptibility to bacterial infection in this population. PMID:21932384

  3. TAK1 regulates NF-{Kappa}B and AP-1 activation in airway epithelial cells following RSV infection

    SciTech Connect

    Dey, Nilay; Liu Tianshuang; Garofalo, Roberto P.; Casola, Antonella

    2011-09-30

    Respiratory syncytial virus (RSV) is the most common cause of epidemic respiratory diseases in infants and young children. RSV infection of airway epithelial cells induces the expression of immune/inflammatory genes through the activation of a subset of transcription factors, including Nuclear Factor-{kappa}B (NF-{kappa}B) and AP-1. In this study, we have investigated the signaling pathway leading to activation of these two transcription factors in response to RSV infection. Our results show that IKK{beta} plays a key role in viral-induced NF-{kappa}B activation, while JNK regulates AP-1-dependent gene transcription, as demonstrated by using kinase inactive proteins and chemical inhibitors of the two kinases. Inhibition of TAK1 activation, by overexpression of kinase inactive TAK1 or using cells lacking TAK1 expression, significantly reduced RSV-induced NF-{kappa}B and AP-1 nuclear translocation and DNA-binding activity, as well as NF-{kappa}B-dependent gene expression, identifying TAK1 as an important upstream signaling molecule regulating RSV-induced NF-{kappa}B and AP-1 activation. - Highlights: > IKK{beta} is a major kinase involved in RSV-induced NF-{kappa}B activation. > JNK regulates AP-1-dependent gene transcription in RSV infection. > TAK1 is a critical upstream signaling molecule for both pathways in infected cells.

  4. Application of speckle image correlation for real-time assessment of metabolic activity in herpes virus-infected cells

    NASA Astrophysics Data System (ADS)

    Vladimirov, A. P.; Malygin, A. S.; Mikhailova, J. A.; Borodin, E. M.; Bakharev, A. A.; Poryvayeva, A. P.

    2014-09-01

    Earlier we reported developing a speckle interferometry technique and a device designed to assess the metabolic activity of a cell monolayer cultivated on a glass substrate. This paper aimed at upgrading the technique and studying its potential for real-time assessment of herpes virus development process. Speckle dynamics was recorded in the image plane of intact and virus-infected cell monolayer. HLE-3, L-41 and Vero cells were chosen as research targets. Herpes simplex virus-1-(HSV-1)- infected cell cultures were studied. For 24 h we recorded the digital value of optical signal I in one pixel and parameter η characterizing change in the distribution of the optical signal on 10 × 10-pixel areas. The coefficient of multiple determination calculated by η time dependences for three intact cell cultures equals 0.94. It was demonstrated that the activity parameters are significantly different for intact and virus-infected cells. The difference of η value for intact and HSV-1-infected cells is detectable 10 minutes from the experiment start.

  5. High-risk oncogenic HPV genotype infection associates with increased immune activation and T cell exhaustion in ART-suppressed HIV-1-infected women.

    PubMed

    Papasavvas, Emmanouil; Surrey, Lea F; Glencross, Deborah K; Azzoni, Livio; Joseph, Jocelin; Omar, Tanvier; Feldman, Michael D; Williamson, Anna-Lise; Siminya, Maureen; Swarts, Avril; Yin, Xiangfan; Liu, Qin; Firnhaber, Cynthia; Montaner, Luis J

    2016-05-01

    Persistence of human papillomavirus (HPV) and cervical disease in the context of HIV co-infection can be influenced by introduction of antiretroviral therapy (ART) and sustained immune activation despite ART. We conducted a cross-sectional study in order to evaluate immune activation/exhaustion in ART-suppressed HIV(+) women with or without high-risk (HR) HPV-related cervical intraepithelial neoplasia (CIN). 55 South African women were recruited in three groups: HR (-) (n = 16) and HR (+) (n = 15) HPV with negative cervical histopathology, and HR (+) HPV with CIN grade 1/2/3 (n = 24). Sampling included endocervical brushing (HPV DNA genotyping), Pap smear (cytology), colposcopic punch biopsy (histopathology, histochemical evaluation of immune cells), and peripheral blood (clinical assessment, flow cytometry-based immune subset characterization). Statistics were done using R2.5.1. Irrespective of the presence of CIN, HR (+) HPV women had higher circulating levels of T cells expressing markers of activation/exhaustion (CD38, PD1, CTLA-4, BTLA, CD160), Tregs, and myeloid subsets expressing corresponding ligands (PDL1, PDL2, CD86, CD40, HVEM) than HR (-) HPV women. A decrease in circulating NK cells was associated with CIN grade. CD4(+) T cell count associated negatively with T cell exhaustion and expression of negative regulators on myeloid cells. Women with CIN when compared to HR (-) HPV women, had higher cervical cell density in stroma and epithelium for CD4(+), CD68(+), and CD11c(+) cells, and only in stroma for CD8(+) cells. We conclude that in ART-suppressed HIV-infected women with HPV co-infection the levels of T and myeloid cell activation/exhaustion are associated with the presence of HR HPV genotypes. PMID:27467943

  6. Nuclease Activity of Legionella pneumophila Cas2 Promotes Intracellular Infection of Amoebal Host Cells

    PubMed Central

    Gunderson, Felizza F.; Mallama, Celeste A.; Fairbairn, Stephanie G.

    2014-01-01

    Legionella pneumophila, the primary agent of Legionnaires' disease, flourishes in both natural and man-made environments by growing in a wide variety of aquatic amoebae. Recently, we determined that the Cas2 protein of L. pneumophila promotes intracellular infection of Acanthamoeba castellanii and Hartmannella vermiformis, the two amoebae most commonly linked to cases of disease. The Cas2 family of proteins is best known for its role in the bacterial and archeal clustered regularly interspaced short palindromic repeat (CRISPR)–CRISPR-associated protein (Cas) system that constitutes a form of adaptive immunity against phage and plasmid. However, the infection event mediated by L. pneumophila Cas2 appeared to be distinct from this function, because cas2 mutants exhibited infectivity defects in the absence of added phage or plasmid and since mutants lacking the CRISPR array or any one of the other cas genes were not impaired in infection ability. We now report that the Cas2 protein of L. pneumophila has both RNase and DNase activities, with the RNase activity being more pronounced. By characterizing a catalytically deficient version of Cas2, we determined that nuclease activity is critical for promoting infection of amoebae. Also, introduction of Cas2, but not its catalytic mutant form, into a strain of L. pneumophila that naturally lacks a CRISPR-Cas locus caused that strain to be 40- to 80-fold more infective for amoebae, unequivocally demonstrating that Cas2 facilitates the infection process independently of any other component encoded within the CRISPR-Cas locus. Finally, a cas2 mutant was impaired for infection of Willaertia magna but not Naegleria lovaniensis, suggesting that Cas2 promotes infection of most but not all amoebal hosts. PMID:25547789

  7. Cytomegalovirus Infection of the Rat Developing Brain In Utero Prominently Targets Immune Cells and Promotes Early Microglial Activation

    PubMed Central

    Cloarec, Robin; Bauer, Sylvian; Luche, Hervé; Buhler, Emmanuelle; Pallesi-Pocachard, Emilie; Salmi, Manal; Courtens, Sandra; Massacrier, Annick; Grenot, Pierre; Teissier, Natacha; Watrin, Françoise; Schaller, Fabienne; Adle-Biassette, Homa; Gressens, Pierre; Malissen, Marie; Stamminger, Thomas; Streblow, Daniel N.; Bruneau, Nadine; Szepetowski, Pierre

    2016-01-01

    Background Congenital cytomegalovirus infections are a leading cause of neurodevelopmental disorders in human and represent a major health care and socio-economical burden. In contrast with this medical importance, the pathophysiological events remain poorly known. Murine models of brain cytomegalovirus infection, mostly neonatal, have brought recent insights into the possible pathogenesis, with convergent evidence for the alteration and possible involvement of brain immune cells. Objectives and Methods In order to confirm and expand those findings, particularly concerning the early developmental stages following infection of the fetal brain, we have created a model of in utero cytomegalovirus infection in the developing rat brain. Rat cytomegalovirus was injected intraventricularly at embryonic day 15 (E15) and the brains analyzed at various stages until the first postnatal day, using a combination of gene expression analysis, immunohistochemistry and multicolor flow cytometry experiments. Results Rat cytomegalovirus infection was increasingly seen in various brain areas including the choroid plexi and the ventricular and subventricular areas and was prominently detected in CD45low/int, CD11b+ microglial cells, in CD45high, CD11b+ cells of the myeloid lineage including macrophages, and in CD45+, CD11b– lymphocytes and non-B non-T cells. In parallel, rat cytomegalovirus infection of the developing rat brain rapidly triggered a cascade of pathophysiological events comprising: chemokines upregulation, including CCL2-4, 7 and 12; infiltration by peripheral cells including B-cells and monocytes at E17 and P1, and T-cells at P1; and microglia activation at E17 and P1. Conclusion In line with previous findings in neonatal murine models and in human specimen, our study further suggests that neuroimmune alterations might play critical roles in the early stages following cytomegalovirus infection of the brain in utero. Further studies are now needed to determine which

  8. Exosomes from HIV-1-infected Cells Stimulate Production of Pro-inflammatory Cytokines through Trans-activating Response (TAR) RNA.

    PubMed

    Sampey, Gavin C; Saifuddin, Mohammed; Schwab, Angela; Barclay, Robert; Punya, Shreya; Chung, Myung-Chul; Hakami, Ramin M; Zadeh, Mohammad Asad; Lepene, Benjamin; Klase, Zachary A; El-Hage, Nazira; Young, Mary; Iordanskiy, Sergey; Kashanchi, Fatah

    2016-01-15

    HIV-1 infection results in a chronic illness because long-term highly active antiretroviral therapy can lower viral titers to an undetectable level. However, discontinuation of therapy rapidly increases virus burden. Moreover, patients under highly active antiretroviral therapy frequently develop various metabolic disorders, neurocognitive abnormalities, and cardiovascular diseases. We have previously shown that exosomes containing trans-activating response (TAR) element RNA enhance susceptibility of undifferentiated naive cells to HIV-1 infection. This study indicates that exosomes from HIV-1-infected primary cells are highly abundant with TAR RNA as detected by RT-real time PCR. Interestingly, up to a million copies of TAR RNA/μl were also detected in the serum from HIV-1-infected humanized mice suggesting that TAR RNA may be stable in vivo. Incubation of exosomes from HIV-1-infected cells with primary macrophages resulted in a dramatic increase of proinflammatory cytokines, IL-6 and TNF-β, indicating that exosomes containing TAR RNA could play a direct role in control of cytokine gene expression. The intact TAR molecule was able to bind to PKR and TLR3 effectively, whereas the 5' and 3' stems (TAR microRNAs) bound best to TLR7 and -8 and none to PKR. Binding of TAR to PKR did not result in its phosphorylation, and therefore, TAR may be a dominant negative decoy molecule in cells. The TLR binding through either TAR RNA or TAR microRNA potentially can activate the NF-κB pathway and regulate cytokine expression. Collectively, these results imply that exosomes containing TAR RNA could directly affect the proinflammatory cytokine gene expression and may explain a possible mechanism of inflammation observed in HIV-1-infected patients under cART.

  9. Bactericidal Activity of Ceragenin CSA-13 in Cell Culture and in an Animal Model of Peritoneal Infection

    PubMed Central

    Niemirowicz, Katarzyna; Wnorowska, Urszula; Byfield, Fitzroy J.; Piktel, Ewelina; Wątek, Marzena; Janmey, Paul A.; Savage, Paul B.

    2015-01-01

    Ceragenins constitute a novel family of cationic antibiotics characterized by a broad spectrum of antimicrobial activities, which have mostly been assessed in vitro. Using a polarized human lung epithelial cell culture system, we evaluated the antibacterial activities of the ceragenin CSA-13 against two strains of Pseudomonas aeruginosa (PAO1 and Xen5). Additionally, the biodistribution and bactericidal activity of a CSA-13–IRDye 800CW derivate were assessed using an animal model of peritoneal infection after PAO1 challenge. In cell culture, CSA-13 bactericidal activities against PAO1 and Xen5 were higher than the activities of the human cathelicidin peptide LL-37. Increased CSA-13 activity was observed in polarized human lung epithelial cell cultures subjected to butyric acid treatment, which is known to increase endogenous LL-37 production. Eight hours after intravenous or intraperitoneal injection, the greatest CSA-13–IRDye 800CW accumulation was observed in mouse liver and kidneys. CSA-13–IRDye 800CW administration resulted in decreased bacterial outgrowth from abdominal fluid collected from animals subjected to intraperitoneal PAO1 infection. These observations indicate that CSA-13 may synergistically interact with antibacterial factors that are naturally present at mucosal surfaces and it maintains its antibacterial activity in the infected abdominal cavity. Cationic lipids such as CSA-13 represent excellent candidates for the development of new antibacterial compounds. PMID:26248361

  10. Frequency of IFNγ-producing T cells correlates with seroreactivity and activated T cells during canine Trypanosoma cruzi infection.

    PubMed

    Hartley, Ashley N; Cooley, Gretchen; Gwyn, Sarah; Orozco, Marcela M; Tarleton, Rick L

    2014-01-01

    Vaccines to prevent Trypanosoma cruzi infection in humans or animals are not available, and in many settings, dogs are an important source of domestic infection for the insect vector. Identification of infected canines is crucial for evaluating peridomestic transmission dynamics and parasite control strategies. As immune control of T. cruzi infection is dependent on humoral and cell-mediated immune responses, we aimed to define a serodiagnostic assay and T cell phenotypic markers for identifying infected dogs and studying the canine T. cruzi-specific immune response. Plasma samples and peripheral blood mononuclear cells (PBMCs) were obtained from forty-two dogs living in a T. cruzi-endemic region. Twenty dogs were known to be seropositive and nine seronegative by conventional serologic tests two years prior to our study. To determine canine seroreactivity, we tested sera or plasma samples in a multiplex bead array against eleven recombinant T. cruzi proteins. Ninety-four percent (17/18) of dogs positive by multiplex serology were initially positive by conventional serology. The frequency of IFNγ-producing cells in PBMCs responding to T. cruzi correlated to serological status, identifying 95% of multiplex seropositive dogs. Intracellular staining identified CD4+ and CD8+ T cell populations as the sources of T. cruzi lysate-induced IFNγ. Low expression of CCR7 and CD62L on CD4+ and CD8+ T cells suggested a predominance of effector/effector memory T cells in seropositive canines. These results are the first, to our knowledge, to correlate T. cruzi-specific antibody responses with T cell responses in naturally infected dogs and validate these methods for identifying dogs exposed to T. cruzi. PMID:24456537

  11. Transient activation of human cytomegalovirus lytic gene expression during latency allows cytotoxic T cell killing of latently infected cells

    PubMed Central

    Krishna, B. A.; Lau, B.; Jackson, S. E.; Wills, M. R.; Sinclair, J. H.; Poole, E.

    2016-01-01

    Human cytomegalovirus (HCMV) latency in the myeloid lineage is maintained by repressive histone modifications around the major immediate early promoter (MIEP), which results in inhibition of the lytic viral life cycle. We now show that pharmacological inhibition of histone deacetylases (HDACs) relieves this repression of the MIEP and induces transient expression of the viral lytic immediate early (IE) antigens but, importantly, not full virus reactivation. In turn, these latently infected cells now become targets for IE-specific cytotoxic T cells (CTLs) which are present at high frequency in all normal healthy HCMV positive carriers but would normally be unable to target latent (lytic antigen-negative) cells. This approach of transiently inducing viral lytic gene expression by HDAC inhibition, in otherwise latently infected cells, offers a window of opportunity to target and purge the latent myeloid cell reservoir by making these normally immunologically undetectable cells visible to pre-existing host immune responses to viral lytic antigens. PMID:27091512

  12. Transient activation of human cytomegalovirus lytic gene expression during latency allows cytotoxic T cell killing of latently infected cells.

    PubMed

    Krishna, B A; Lau, B; Jackson, S E; Wills, M R; Sinclair, J H; Poole, E

    2016-01-01

    Human cytomegalovirus (HCMV) latency in the myeloid lineage is maintained by repressive histone modifications around the major immediate early promoter (MIEP), which results in inhibition of the lytic viral life cycle. We now show that pharmacological inhibition of histone deacetylases (HDACs) relieves this repression of the MIEP and induces transient expression of the viral lytic immediate early (IE) antigens but, importantly, not full virus reactivation. In turn, these latently infected cells now become targets for IE-specific cytotoxic T cells (CTLs) which are present at high frequency in all normal healthy HCMV positive carriers but would normally be unable to target latent (lytic antigen-negative) cells. This approach of transiently inducing viral lytic gene expression by HDAC inhibition, in otherwise latently infected cells, offers a window of opportunity to target and purge the latent myeloid cell reservoir by making these normally immunologically undetectable cells visible to pre-existing host immune responses to viral lytic antigens. PMID:27091512

  13. Transient activation of human cytomegalovirus lytic gene expression during latency allows cytotoxic T cell killing of latently infected cells.

    PubMed

    Krishna, B A; Lau, B; Jackson, S E; Wills, M R; Sinclair, J H; Poole, E

    2016-01-01

    Human cytomegalovirus (HCMV) latency in the myeloid lineage is maintained by repressive histone modifications around the major immediate early promoter (MIEP), which results in inhibition of the lytic viral life cycle. We now show that pharmacological inhibition of histone deacetylases (HDACs) relieves this repression of the MIEP and induces transient expression of the viral lytic immediate early (IE) antigens but, importantly, not full virus reactivation. In turn, these latently infected cells now become targets for IE-specific cytotoxic T cells (CTLs) which are present at high frequency in all normal healthy HCMV positive carriers but would normally be unable to target latent (lytic antigen-negative) cells. This approach of transiently inducing viral lytic gene expression by HDAC inhibition, in otherwise latently infected cells, offers a window of opportunity to target and purge the latent myeloid cell reservoir by making these normally immunologically undetectable cells visible to pre-existing host immune responses to viral lytic antigens.

  14. Bos taurus papillomavirus activity in peripheral blood mononuclear cells: demonstrating a productive infection.

    PubMed

    Melo, T C; Araldi, R P; Pessoa, N S D; de-Sá-Júnior, P L; Carvalho, R F; Beçak, W; Stocco, R C

    2015-12-11

    Bovine papillomavirus (BPV) is an oncogenic virus with mucous and epithelial tropism. Possible productive virus infection in other tissues, such as blood, has been hypothesized. In order to investigate this possibility, three samples of skin papillomas and blood were collected from bovines with BPV infection and five samples of peripheral blood and one sample of normal tissue were collected from a calf without BPV infection. Peripheral blood mononuclear cells (PBMCs) were isolated from whole blood and examined by reverse transcription-polymerase chain reaction, immunofluorescence, in situ hybridization, and electron microscopy. The tissue samples were examined for histopathological and immunohistochemical features. The skin papillomas showed the presence of DNA sequences of BPV-2, BPV-11, and a putative virus type. The blood samples showed DNA sequences of BPV-1, 2, and 4 simultaneously. Immunohistochemistry showed BPV L1 protein in both epithelium and stroma and BPV E2 protein in koilocytes. In situ hybridization confirmed the presence of BPV DNA in PBMCs and immunofluorescence showed nuclear labeling of E2 and L1 BPV proteins in PBMCs. The transcription analysis revealed transcripts of BPV-1 L1, BPV-2 L2, and BPV-4 E7 in blood and papilloma samples of BPV-infected cattle. The comet assay revealed high levels of host cell DNA damage upon BPV infection. Electron microscopy analysis of PBMCs identified the presence of particles in the cytoplasm that are consistent with papillomavirus in size and shape. The productive infection of PBMCs with BPV has been previously discussed and this study provides evidence indicating that PBMCs are a target of BPV.

  15. Mechanisms of liver fibrosis associated with experimental Fasciola hepatica infection: roles of Fas2 proteinase and hepatic stellate cell activation.

    PubMed

    Marcos, Luis A; Terashima, Angélica; Yi, Pedro; Andrade, Roy; Cubero, Francisco J; Albanis, Efsevia; Gotuzzo, Eduardo; Espinoza, Jose R; Friedman, Scott L

    2011-02-01

    We have evaluated the possible mechanisms of liver fibrosis caused by Fasciola hepatica in an animal model and in culture using immortalized human stellate cells. Liver biopsies of F. hepatica-infected rats were performed at wk 8 and 16. Serum-starved LX-2 cells, a human stellate cell line, were exposed to increasing concentrations of Fas2 antigen. The expression of key fibrosis-related genes was evaluated by qRT-PCR. There was a significant correlation between fibrogenic gene expression and both intensity and duration of infection. LX-2 cells exposed to Fas2 showed progressively increased expression of mRNAs for Collagen I, alpha-smooth muscle-actin, platelet-derived growth factor beta receptor, and tissue inhibitor of metalloproteinase II; inhibition of Fas2 cysteine proteinase activity by E-64 abrogated these increases, suggesting that the protease activity of Fas2 is involved in fibrogenic stimulation. In summary, F. hepatica infection is associated with up-regulation of mRNAs associated with hepatic fibrogenesis in vivo and in activated hepatic stellate cells.

  16. Peroxisome-proliferator-activated receptor-{gamma} agonists inhibit the release of proinflammatory cytokines from RSV-infected epithelial cells

    SciTech Connect

    Arnold, Ralf . E-mail: ralf.arnold@medizin.uni-magdeburg.de; Koenig, Wolfgang

    2006-03-15

    The epithelial cells of the airways are the target cells for respiratory syncytial virus (RSV) infection and the site of the majority of the inflammation associated with the disease. Recently, peroxisome-proliferator-activated receptor {gamma} (PPAR{gamma}), a member of the nuclear hormone receptor superfamily, has been shown to possess anti-inflammatory properties. Therefore, we investigated the role of PPAR{gamma} agonists (15d-PGJ{sub 2}, ciglitazone and troglitazone) on the synthesis of RSV-induced cytokine release from RSV-infected human lung epithelial cells (A549). We observed that all PPAR{gamma} ligands inhibited dose-dependently the release of TNF-{alpha}, GM-CSF, IL-1{alpha}, IL-6 and the chemokines CXCL8 (IL-8) and CCL5 (RANTES) from RSV-infected A549 cells. Concomitantly, the PPAR{gamma} ligands diminished the cellular amount of mRNA encoding for IL-6, CXCL8 and CCL5 and the RSV-induced binding activity of the transcription factors NF-{kappa}B (p65/p50) and AP-1 (c-fos), respectively. Our data presented herein suggest a potential application of PPAR{gamma} ligands in the anti-inflammatory treatment of RSV infection.

  17. Identification and characterization of a DNA primase activity present in herpes simplex virus type 1-infected HeLa cells.

    PubMed

    Holmes, A M; Wietstock, S M; Ruyechan, W T

    1988-03-01

    A novel DNA primase activity has been identified in HeLa cells infected with herpes simplex virus type 1 (HSV-1). Such an activity has not been detected in mock-infected cells. The primase activity coeluted with a portion of HSV-1 DNA polymerase from single-stranded DNA agarose columns loaded with high-salt extracts derived from infected cells. This DNA primase activity could be distinguished from host HeLa cell DNA primase by several criteria. First, the pH optimum of the HSV primase was relatively broad and peaked at 8.2 to 8.7 pH units. In contrast, the pH optimum of the HeLa DNA primase was very sharp and fell between pH 7.9 and 8.2. Second, freshly isolated HSV DNA primase was less salt sensitive than the HeLa primase and was eluted from single-stranded DNA agarose at higher salt concentrations than the host primase. Third, antibodies raised against individual peptides of the calf thymus DNA polymerase:primase complex cross-reacted with the HeLa primase but did not react with the HSV DNA primase. Fourth, freshly prepared HSV DNA primase appeared to be associated with the HSV polymerase, but after storage at 4 degrees C for several weeks, the DNA primase separated from the viral DNA polymerase. Separation or decoupling could also be achieved by gel filtration of the HSV polymerase:primase. This free DNA primase had an apparent molecular size of approximately 40 kilodaltons, whereas free HeLa DNA primase had an apparent molecular size of approximately 110 kilodaltons. On the basis of these data, we believe that the novel DNA primase activity in HSV-infected cells may be virus coded and that this enzyme represents a new and important function involved in the replication of HSV DNA.

  18. Rapid and transient activation of γδ T cells to IFN-γ production, NK cell-like killing, and antigen processing during acute virus infection.

    PubMed

    Toka, Felix N; Kenney, Mary A; Golde, William T

    2011-04-15

    γδ T cells are the majority peripheral blood T cells in young cattle. The role of γδ T cells in innate responses against infection with foot-and-mouth disease virus was analyzed on consecutive 5 d following infection. Before infection, bovine WC1(+) γδ T cells expressed a nonactivated phenotype relative to CD62L, CD45RO, and CD25 expression and did not produce IFN-γ ex vivo. Additionally, CD335 expression was lacking and no spontaneous target cell lysis could be detected in vitro, although perforin was detectable at a very low level. MHC class II and CD13 expression were also lacking. Following infection with foot-and-mouth disease virus, expression of CD62L and CD45RO was greatly reduced on WC1(+) γδ T cells, and unexpectedly, CD45RO expression did not recover. A transient increase in expression of CD25 correlated with production of IFN-γ. Expression of CD335 and production of perforin were detected on a subset of γδ T cells, and this correlated with an increased spontaneous killing of xenogeneic target cells. Furthermore, increased MHC class II expression was detected on WC1(+) γδ T cells, and these cells processed protein Ags. These activities are rapidly induced, within 3 d, and wane by 5 d following infection. All of these functions, NK-like killing, Ag processing, and IFN-γ production, have been demonstrated for these cells in various species. However, these results are unique in that all these functions are detected in the same samples of WC1(+) γδ T cells, suggesting a pivotal role of these cells in controlling virus infection.

  19. Magnitude and kinetics of CD8+ T cell activation during hyperacute HIV infection impacts viral set point

    PubMed Central

    Ndhlovu, Zaza; Kamya, Philomena; Mewalal, Nikoshia; Kløverpris, Henrik N.; Nkosi, Thandeka; Pretorius, Karyn; Laher, Faatima; Ogunshola, Funsho; Chopera, Denis; Shekhar, Karthik; Ghebremichael, Musie; Ismail, Nasreen; Moodley, Amber; Malik, Amna; Leslie, Alasdair; Goulder, Philip J.R; Buus, Søren; Chakraborty, Arup; Dong, Krista; Ndung’u, Thumbi; Walker, Bruce D.

    2015-01-01

    Summary CD8+ T cells contribute to the control of HIV, but it is not clear whether initial immune responses modulate the viral set point. We screened high-risk uninfected women twice a week for plasma HIV RNA and identified twelve hyperacute infections. Onset of viremia elicited a massive HIV-specific CD8+ T cell response, with limited bystander activation of non-HIV memory CD8+ T cells. HIV-specific CD8+ T cells secreted little interferon-γ, underwent rapid apoptosis and failed to upregulate the interleukin 7 receptor, known to be important for T cell survival. The rapidity to peak CD8+ T cell activation and the absolute magnitude of activation induced by the exponential rise in viremia were inversely correlated with set point viremia. These data indicate that rapid, high magnitude HIV-induced CD8+ T cell responses are crucial for subsequent immune control of acute infection, which has important implications for HIV vaccine design. PMID:26362266

  20. A primary cell model of HIV-1 latency that uses activation through the T cell receptor and return to quiescence to establish latent infection

    PubMed Central

    Kim, Michelle; Hosmane, Nina N.; Bullen, C. Korin; Capoferri, Adam; Yang, Hung-Chih; Siliciano, Janet D.; Siliciano, Robert F.

    2015-01-01

    A mechanistic understanding of HIV-1 latency depends upon a model system that recapitulates the in vivo condition of latently infected, resting CD4+ T lymphocytes. Latency appears to be established after activated CD4+ T cells, the principal targets of HIV-1 infection, become productively infected and survive long enough to return to a resting memory state in which viral expression is inhibited by changes in the cellular environment. This protocol describes an ex vivo primary cell system that is generated under conditions that reflect the in vivo establishment of latency. Creation of these latency model cells takes 12 weeks and, once established, the cells can be maintained and used for several months. The resulting cell population contains both uninfected and latently infected cells. This primary cell model can be used to perform drug screens, study CTL responses to HIV-1, compare viral alleles, or to expand the ex vivo lifespan of cells from HIV-1 infected individuals for extended study. PMID:25375990

  1. CD4 T-Cell Responses in Primary HIV Infection: Interrelationship with Immune Activation and Virus Burden

    PubMed Central

    Chevalier, Mathieu F.; Didier, Céline; Girard, Pierre-Marie; Manea, Maria E.; Campa, Pauline; Barré-Sinoussi, Françoise; Scott-Algara, Daniel; Weiss, Laurence

    2016-01-01

    Early events during primary HIV infection (PHI) are thought to influence disease outcome. Although a growing body of evidence suggests a beneficial role of HIV-specific CD4 help in HIV infection, it is unclear how early viral replication, systemic immune activation, and antiretroviral therapy (ART) may shape CD4 T-cell responses during PHI, and whether HIV-specific CD4 responses contribute to the high immune activation observed in PHI. Twenty-seven patients with early PHI were included in a prospective longitudinal study and 12 of them received ART after enrollment. Fresh peripheral blood mononuclear cells were used for measurement of ex vivo T-cell activation and of cytokine-producing CD4 T-cells following stimulation with PMA/ionomycin or HIV-1-gag-p24 antigen. Patients were segregated based on CD8 T-cell activation level (i.e., % HLA-DR+CD38+ CD8 T-cells) at baseline (BL). Patients with lower immune activation exhibited higher frequency of bulk CD4 T-cells producing IFN-γ or IL-17 and higher effector-to-regulatory cell ratios. No differences were found in HIV-specific CD4 T-cell frequencies. In contrast, segregation of patients based on plasma viral load (pVL) revealed that patients with higher pVL showed higher cytokine-producing HIV-specific CD4 responses. Of note, the frequency of IFN-γ+ HIV-specific CD4 T cells significantly diminished between BL and month 6 only in ART-treated patients. However, early treatment initiation was associated with better maintenance of HIV-specific IFN-γ+ CD4 T-cells. These data suggest that HIV-specific CD4 responses do not fuel systemic T-cell activation and are driven by viral replication but not able to contribute to its control in the early phase of infection. Moreover, our data also suggest a benefit of early treatment for the maintenance of HIV-specific CD4 T-cell help. PMID:27746782

  2. Functional profile of CD4+ and CD8+ T cells in latently infected individuals and patients with active TB.

    PubMed

    Marín, Nancy D; París, Sara C; Rojas, Mauricio; García, Luis F

    2013-03-01

    Tuberculosis (TB) is one of the most important infectious diseases around the world. Several studies have focused on the identification of correlates of protection against TB. Most of them have concentrated on the study of IFN-γ due to its robust association with protection against TB. However, given the complexity of the immune response elicited after Mtb infection, other cytokines should also be considered. In the present study, we evaluated Th1 and Th17 responses and their association with the protection or development of active disease. Therefore, non infected individuals (nonTBi), latently infected individuals (LTBi) and patients with active TB (ATB) were studied. The evaluation of the number of cytokine producing cells by ELISPOT showed a higher number of IFN-γ-producing cells in ATB patients, but no differences were found regarding the number of IL-17 producing cells among studied groups. The evaluation of IFN-γ, IL-2, TNF-α and IL-17 producing CD4+ and CD8+ T cells at 1 day and 6 days of stimulation with mycobacterial antigens suggests the presence of functional signatures associated with latency or active TB. The results presented herein suggest the possible use of the evaluation of Th1-type cytokines, such as IFN-γ and/or TNF-α, as a correlate of protection against TB; however, these results need to be validated for other groups.

  3. Inhibition of host extracellular signal-regulated kinase (ERK) activation decreases new world alphavirus multiplication in infected cells

    SciTech Connect

    Voss, Kelsey; Amaya, Moushimi; Mueller, Claudius; Roberts, Brian; Kehn-Hall, Kylene; Bailey, Charles; Petricoin, Emanuel; Narayanan, Aarthi

    2014-11-15

    New World alphaviruses belonging to the family Togaviridae are classified as emerging infectious agents and Category B select agents. Our study is focused on the role of the host extracellular signal-regulated kinase (ERK) in the infectious process of New World alphaviruses. Infection of human cells by Venezuelan equine encephalitis virus (VEEV) results in the activation of the ERK-signaling cascade. Inhibition of ERK1/2 by the small molecule inhibitor Ag-126 results in inhibition of viral multiplication. Ag-126-mediated inhibition of VEEV was due to potential effects on early and late stages of the infectious process. While expression of viral proteins was down-regulated in Ag-126 treated cells, we did not observe any influence of Ag-126 on the nuclear distribution of capsid. Finally, Ag-126 exerted a broad-spectrum inhibitory effect on New World alphavirus multiplication, thus indicating that the host kinase, ERK, is a broad-spectrum candidate for development of novel therapeutics against New World alphaviruses. - Highlights: • VEEV infection activated multiple components of the ERK signaling cascade. • Inhibition of ERK activation using Ag-126 inhibited VEEV multiplication. • Activation of ERK by Ceramide C6 increased infectious titers of TC-83. • Ag-126 inhibited virulent strains of all New World alphaviruses. • Ag-126 treatment increased percent survival of infected cells.

  4. The predominance of alternatively activated macrophages following challenge with cell wall peptide-polysaccharide after prior infection with Sporothrix schenckii.

    PubMed

    Alegranci, Pamela; de Abreu Ribeiro, Livia Carolina; Ferreira, Lucas Souza; Negrini, Thais de Cássia; Maia, Danielle Cardoso Geraldo; Tansini, Aline; Gonçalves, Amanda Costa; Placeres, Marisa Campos Polesi; Carlos, Iracilda Zeppone

    2013-08-01

    Sporotrichosis is a subcutaneous mycosis that is caused by the dimorphic fungus Sporothrix schenckii. This disease generally occurs within the skin and subcutaneous tissues, causing lesions that can spread through adjacent lymphatic vessels and sometimes leading to systemic diseases in immunocompromised patients. Macrophages are crucial for proper immune responses against a variety of pathogens. Furthermore, macrophages can play different roles in response to different microorganisms and forms of activation, and they can be divided into "classic" or "alternatively" activated populations, as also known as M1 and M2 macrophages. M1 cells can lead to tissue injury and contribute to pathogenesis, whereas M2 cells promote angiogenesis, tissue remodeling, and repair. The aim of this study was to investigate the roles of M1 and M2 macrophages in a sporotrichosis model. Toward this end, we performed phenotyping of peritoneal exudate cells and evaluated the concomitant production of several immunomediators, including IL-12, IL-10, TGF-β, nitric oxide, and arginase-I activity, which were stimulated ex vivo with cell wall peptide-polysaccharide. Our results showed the predominance of the M2 macrophage population, indicated by peaks of arginase-I activity as well as IL-10 and TGF-β production during the 6th and 8th weeks after infection. These results were consistent with cellular phenotyping that revealed increases in CD206-positive cells over this period. This is the first report of the participation of M2 macrophages in sporotrichosis infections.

  5. Lymphotoxin activation by human T-cell leukemia virus type I-infected cell lines: role for NF-kappa B.

    PubMed

    Paul, N L; Lenardo, M J; Novak, K D; Sarr, T; Tang, W L; Ruddle, N H

    1990-11-01

    Human T-cell leukemia virus type I (HTLV-I)-infected T-cell lines constitutively produce high levels of biologically active lymphotoxin (LT; tumor necrosis factor-beta) protein and LT mRNA. To understand the regulation of LT transcription by HTLV-I, we analyzed the ability of a series of deletions of the LT promoter to drive the chloramphenicol acetyltransferase (CAT) reporter gene in HTLV-I-positive MT-2 cells. The smallest LT promoter fragment (-140 to +77) that was able to drive CAT activity contained a site that was similar to the immunoglobulin kappa-chain NF-kappa B-binding site. Since the HTLV-I tax gene activates the nuclear form of NF-kappa B, this finding suggested a possible means of HTLV-I activation of LT production. We found that the LT kappa B-like site specifically formed a complex with NF-kappa B-containing nuclear extract from MT-2, C81-66-45, and other activated T cells. Mutation of the LT kappa B site in the context of the LT promoter (-293 to +77) (mutant M1) reduced the ability of the promoter to drive the CAT gene in HTLV-I-infected and noninfected human T-cell lines. These data suggest a general role for NF-kappa B activation in the induction of LT gene transcription. Activation of LT in HTLV-I-infected cells may explain the pathology associated with HTLV-I infection, including the hypercalcemia that is prevalent in adult T-cell leukemia.

  6. CIP2A Promotes T-Cell Activation and Immune Response to Listeria monocytogenes Infection.

    PubMed

    Côme, Christophe; Cvrljevic, Anna; Khan, Mohd Moin; Treise, Irina; Adler, Thure; Aguilar-Pimentel, Juan Antonio; Au-Yeung, Byron; Sittig, Eleonora; Laajala, Teemu Daniel; Chen, Yiling; Oeder, Sebastian; Calzada-Wack, Julia; Horsch, Marion; Aittokallio, Tero; Busch, Dirk H; Ollert, Markus W; Neff, Frauke; Beckers, Johannes; Gailus-Durner, Valerie; Fuchs, Helmut; Hrabě de Angelis, Martin; Chen, Zhi; Lahesmaa, Riitta; Westermarck, Jukka

    2016-01-01

    The oncoprotein Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A) is overexpressed in most malignancies and is an obvious candidate target protein for future cancer therapies. However, the physiological importance of CIP2A-mediated PP2A inhibition is largely unknown. As PP2A regulates immune responses, we investigated the role of CIP2A in normal immune system development and during immune response in vivo. We show that CIP2A-deficient mice (CIP2AHOZ) present a normal immune system development and function in unchallenged conditions. However when challenged with Listeria monocytogenes, CIP2AHOZ mice display an impaired adaptive immune response that is combined with decreased frequency of both CD4+ T-cells and CD8+ effector T-cells. Importantly, the cell autonomous effect of CIP2A deficiency for T-cell activation was confirmed. Induction of CIP2A expression during T-cell activation was dependent on Zap70 activity. Thus, we reveal CIP2A as a hitherto unrecognized mediator of T-cell activation during adaptive immune response. These results also reveal CIP2AHOZ as a possible novel mouse model for studying the role of PP2A activity in immune regulation. On the other hand, the results also indicate that CIP2A targeting cancer therapies would not cause serious immunological side-effects.

  7. CIP2A Promotes T-Cell Activation and Immune Response to Listeria monocytogenes Infection

    PubMed Central

    Cvrljevic, Anna; Khan, Mohd Moin; Treise, Irina; Adler, Thure; Aguilar-Pimentel, Juan Antonio; Au-Yeung, Byron; Sittig, Eleonora; Laajala, Teemu Daniel; Chen, Yiling; Oeder, Sebastian; Calzada-Wack, Julia; Horsch, Marion; Aittokallio, Tero; Busch, Dirk H.; Ollert, Markus W.; Neff, Frauke; Beckers, Johannes; Gailus-Durner, Valerie; Fuchs, Helmut; de Angelis, Martin Hrabě; Chen, Zhi; Lahesmaa, Riitta; Westermarck, Jukka

    2016-01-01

    The oncoprotein Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A) is overexpressed in most malignancies and is an obvious candidate target protein for future cancer therapies. However, the physiological importance of CIP2A-mediated PP2A inhibition is largely unknown. As PP2A regulates immune responses, we investigated the role of CIP2A in normal immune system development and during immune response in vivo. We show that CIP2A-deficient mice (CIP2AHOZ) present a normal immune system development and function in unchallenged conditions. However when challenged with Listeria monocytogenes, CIP2AHOZ mice display an impaired adaptive immune response that is combined with decreased frequency of both CD4+ T-cells and CD8+ effector T-cells. Importantly, the cell autonomous effect of CIP2A deficiency for T-cell activation was confirmed. Induction of CIP2A expression during T-cell activation was dependent on Zap70 activity. Thus, we reveal CIP2A as a hitherto unrecognized mediator of T-cell activation during adaptive immune response. These results also reveal CIP2AHOZ as a possible novel mouse model for studying the role of PP2A activity in immune regulation. On the other hand, the results also indicate that CIP2A targeting cancer therapies would not cause serious immunological side-effects. PMID:27100879

  8. Control of pathogenic effector T-cell activities in situ by PD-L1 expression on respiratory inflammatory dendritic cells during respiratory syncytial virus infection

    PubMed Central

    Yao, S; Jiang, L; Moser, EK; Jewett, LB; Wright, J; Du, J; Zhou, B; Davis, SD; Krupp, NL; Braciale, TJ; Sun, J

    2015-01-01

    Respiratory syncytial virus (RSV) infection is a leading cause of severe lower respiratory tract illness in young infants, the elderly and immunocompromised individuals. We demonstrate here that the co-inhibitory molecule programmed cell death 1 (PD-1) is selectively upregulated on T cells within the respiratory tract during both murine and human RSV infection. Importantly, the interaction of PD-1 with its ligand PD-L1 is vital to restrict the pro-inflammatory activities of lung effector T cells in situ, thereby inhibiting the development of excessive pulmonary inflammation and injury during RSV infection. We further identify that PD-L1 expression on lung inflammatory dendritic cells is critical to suppress inflammatory T-cell activities, and an interferon–STAT1–IRF1 axis is responsible for increased PD-L1 expression on lung inflammatory dendritic cells. Our findings suggest a potentially critical role of PD-L1 and PD-1 interactions in the lung for controlling host inflammatory responses and disease progression in clinical RSV infection. PMID:25465101

  9. Longitudinal characterization of dysfunctional T cell-activation during human acute Ebola infection

    PubMed Central

    Agrati, C; Castilletti, C; Casetti, R; Sacchi, A; Falasca, L; Turchi, F; Tumino, N; Bordoni, V; Cimini, E; Viola, D; Lalle, E; Bordi, L; Lanini, S; Martini, F; Nicastri, E; Petrosillo, N; Puro, V; Piacentini, M; Di Caro, A; Kobinger, G P; Zumla, A; Ippolito, G; Capobianchi, M R

    2016-01-01

    Data on immune responses during human Ebola virus disease (EVD) are scanty, due to limitations imposed by biosafety requirements and logistics. A sustained activation of T-cells was recently described but functional studies during the acute phase of human EVD are still missing. Aim of this work was to evaluate the kinetics and functionality of T-cell subsets, as well as the expression of activation, autophagy, apoptosis and exhaustion markers during the acute phase of EVD until recovery. Two EVD patients admitted to the Italian National Institute for Infectious Diseases, Lazzaro Spallanzani, were sampled sequentially from soon after symptom onset until recovery and analyzed by flow cytometry and ELISpot assay. An early and sustained decrease of CD4 T-cells was seen in both patients, with an inversion of the CD4/CD8 ratio that was reverted during the recovery period. In parallel with the CD4 T-cell depletion, a massive T-cell activation occurred and was associated with autophagic/apoptotic phenotype, enhanced expression of the exhaustion marker PD-1 and impaired IFN-gamma production. The immunological impairment was accompanied by EBV reactivation. The association of an early and sustained dysfunctional T-cell activation in parallel to an overall CD4 T-cell decline may represent a previously unknown critical point of Ebola virus (EBOV)-induced immune subversion. The recent observation of late occurrence of EBOV-associated neurological disease highlights the importance to monitor the immuno-competence recovery at discharge as a tool to evaluate the risk of late sequelae associated with resumption of EBOV replication. Further studies are required to define the molecular mechanisms of EVD-driven activation/exhaustion and depletion of T-cells. PMID:27031961

  10. Longitudinal characterization of dysfunctional T cell-activation during human acute Ebola infection.

    PubMed

    Agrati, C; Castilletti, C; Casetti, R; Sacchi, A; Falasca, L; Turchi, F; Tumino, N; Bordoni, V; Cimini, E; Viola, D; Lalle, E; Bordi, L; Lanini, S; Martini, F; Nicastri, E; Petrosillo, N; Puro, V; Piacentini, M; Di Caro, A; Kobinger, G P; Zumla, A; Ippolito, G; Capobianchi, M R

    2016-01-01

    Data on immune responses during human Ebola virus disease (EVD) are scanty, due to limitations imposed by biosafety requirements and logistics. A sustained activation of T-cells was recently described but functional studies during the acute phase of human EVD are still missing. Aim of this work was to evaluate the kinetics and functionality of T-cell subsets, as well as the expression of activation, autophagy, apoptosis and exhaustion markers during the acute phase of EVD until recovery. Two EVD patients admitted to the Italian National Institute for Infectious Diseases, Lazzaro Spallanzani, were sampled sequentially from soon after symptom onset until recovery and analyzed by flow cytometry and ELISpot assay. An early and sustained decrease of CD4 T-cells was seen in both patients, with an inversion of the CD4/CD8 ratio that was reverted during the recovery period. In parallel with the CD4 T-cell depletion, a massive T-cell activation occurred and was associated with autophagic/apoptotic phenotype, enhanced expression of the exhaustion marker PD-1 and impaired IFN-gamma production. The immunological impairment was accompanied by EBV reactivation. The association of an early and sustained dysfunctional T-cell activation in parallel to an overall CD4 T-cell decline may represent a previously unknown critical point of Ebola virus (EBOV)-induced immune subversion. The recent observation of late occurrence of EBOV-associated neurological disease highlights the importance to monitor the immuno-competence recovery at discharge as a tool to evaluate the risk of late sequelae associated with resumption of EBOV replication. Further studies are required to define the molecular mechanisms of EVD-driven activation/exhaustion and depletion of T-cells.

  11. Longitudinal characterization of dysfunctional T cell-activation during human acute Ebola infection.

    PubMed

    Agrati, C; Castilletti, C; Casetti, R; Sacchi, A; Falasca, L; Turchi, F; Tumino, N; Bordoni, V; Cimini, E; Viola, D; Lalle, E; Bordi, L; Lanini, S; Martini, F; Nicastri, E; Petrosillo, N; Puro, V; Piacentini, M; Di Caro, A; Kobinger, G P; Zumla, A; Ippolito, G; Capobianchi, M R

    2016-01-01

    Data on immune responses during human Ebola virus disease (EVD) are scanty, due to limitations imposed by biosafety requirements and logistics. A sustained activation of T-cells was recently described but functional studies during the acute phase of human EVD are still missing. Aim of this work was to evaluate the kinetics and functionality of T-cell subsets, as well as the expression of activation, autophagy, apoptosis and exhaustion markers during the acute phase of EVD until recovery. Two EVD patients admitted to the Italian National Institute for Infectious Diseases, Lazzaro Spallanzani, were sampled sequentially from soon after symptom onset until recovery and analyzed by flow cytometry and ELISpot assay. An early and sustained decrease of CD4 T-cells was seen in both patients, with an inversion of the CD4/CD8 ratio that was reverted during the recovery period. In parallel with the CD4 T-cell depletion, a massive T-cell activation occurred and was associated with autophagic/apoptotic phenotype, enhanced expression of the exhaustion marker PD-1 and impaired IFN-gamma production. The immunological impairment was accompanied by EBV reactivation. The association of an early and sustained dysfunctional T-cell activation in parallel to an overall CD4 T-cell decline may represent a previously unknown critical point of Ebola virus (EBOV)-induced immune subversion. The recent observation of late occurrence of EBOV-associated neurological disease highlights the importance to monitor the immuno-competence recovery at discharge as a tool to evaluate the risk of late sequelae associated with resumption of EBOV replication. Further studies are required to define the molecular mechanisms of EVD-driven activation/exhaustion and depletion of T-cells. PMID:27031961

  12. Active hepatitis C virus infection in bone marrow and peripheral blood mononuclear cells from patients with mixed cryoglobulinaemia.

    PubMed Central

    Gabrielli, A; Manzin, A; Candela, M; Caniglia, M L; Paolucci, S; Danieli, M G; Clementi, M

    1994-01-01

    The presence of hepatitis C virus (HCV) genomic sequences was checked in plasma, liver, peripheral blood mononuclear cells (PBMC) and bone marrow cells from 11 patients with mixed cryoglobulinaemia positive for anti-HCV antibodies, and from 11 patients with chronic HCV hepatitis without serological evidence of cryoglobulinaemia. HCV RNA sequences were demonstrated by reverse transcription polymerase chain reaction in seven plasma samples, in six PBMC samples, and in seven bone marrow cell samples from the 11 cryoglobulinaemic subjects; otherwise, viral specific nucleic acids were detected in 10 plasma samples, in one PBMC sample, and in two bone marrow cell samples from the 11 patients with chronic hepatitis. The HCV replicative intermediate was evidenced in four of the six PBMC and in five of the seven bone marrow aspirate HCV RNA-positive samples. Analysis of subpopulations isolated from bone marrow and peripheral blood samples showed HCV RNA sequences in mononuclear cells belonging either the CD2+ subset or to the CD19+ subpopulation or to the adherent cells. Finally, we compared the nucleotide sequences of a large portion (-270 to -59) of the HCV 5'-untranslated region from five patients with mixed cryoglobulinaemia and from seven patients with chronic hepatitis without cryoglobulinaemia; the degree of heterogeneity, compared with the prototype HCV sequence, was similar in both groups. These findings from two groups of HCV-infected patients indicate that transient or permanent active HCV infection of bone marrow and PBMC is frequent in anti-HCV-positive patients with mixed cryoglobulinaemia, and suggest that extra-hepatic infection may play a major role in influencing the pathophysiology of this infection as well as the viral persistence. Images Fig. 1 PMID:8033425

  13. Suppression of ERK activation in urethral epithelial cells infected with Neisseria gonorrhoeae and its isogenic minD mutant contributes to anti-apoptosis.

    PubMed

    Liu, GuanQun L; Parti, Rajinder P; Dillon, Jo-Anne R

    2015-04-01

    In gonococci-infected transduced human urethral epithelial cells (THUEC), the role of ERK, a mitogen-activated protein kinase (MAPK), in apoptosis is unknown. We observed lowering of ERK activation in THUEC following infection with anti-apoptosis-inducing Neisseria gonorrhoeae strain CH811. An isogenic cell division mutant of this strain, Ng CJSD1 (minD deficient), which is large and abnormally shaped, reduced ERK phosphorylation levels even more than its parental strain in THUEC. This led to higher anti-apoptosis in mutant-infected cells as compared to the parental strain-infected cells. Our results suggest that N. gonorrhoeae infection reduces ERK activation in THUEC contributing to anti-apoptosis.

  14. Effects of co-infection with hepatitis C virus and GB virus C on CD4 cell count and HIV-RNA level among HIV-infected patients treated with highly active antiretroviral therapy.

    PubMed

    Voirin, Nicolas; Trépo, Christian; Estève, Jacques; Chevallier, Philippe; Ritter, Jacques; Fabry, Jacques; Vanhems, Philippe

    2002-07-26

    The effects of co-infection with hepatitis C virus (HCV) and GB virus C (GBV-C) on CD4 cell counts and plasma HIV-RNA levels has been investigated in HIV-infected patients treated with highly active antiretroviral therapy (HAART). Patients co-infected with HCV and GBV-C experienced a CD4 cell increase during 4 years of HAART, whereas the increase stopped after 2 years in the other groups.

  15. Phosphoproteomic Analysis of KSHV-Infected Cells Reveals Roles of ORF45-Activated RSK during Lytic Replication

    PubMed Central

    Avey, Denis; Tepper, Sarah; Li, Wenwei; Turpin, Zachary; Zhu, Fanxiu

    2015-01-01

    Kaposi’s Sarcoma-Associated Herpesvirus (KSHV) is an oncogenic virus which has adapted unique mechanisms to modulate the cellular microenvironment of its human host. The pathogenesis of KSHV is intimately linked to its manipulation of cellular signaling pathways, including the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) pathway. We have previously shown that KSHV ORF45 contributes to the sustained activation of both ERK and p90 ribosomal S6 kinase (RSK, a major functional mediator of ERK/MAPK signaling) during KSHV lytic replication. ORF45-activated RSK is required for optimal KSHV lytic gene expression and progeny virion production, though the underlying mechanisms downstream of this activation are still unclear. We hypothesized that the activation of RSK by ORF45 causes differential phosphorylation of cellular and viral substrates, affecting biological processes essential for efficient KSHV lytic replication. Accordingly, we observed widespread and significant differences in protein phosphorylation upon induction of lytic replication. Mass-spectrometry-based phosphoproteomic screening identified putative substrates of ORF45-activated RSK in KSHV-infected cells. Bioinformatic analyses revealed that nuclear proteins, including several transcriptional regulators, were overrepresented among these candidates. We validated the ORF45/RSK-dependent phosphorylation of several putative substrates by employing KSHV BAC mutagenesis, kinase inhibitor treatments, and/or CRISPR-mediated knockout of RSK in KSHV-infected cells. Furthermore, we assessed the consequences of knocking out these substrates on ORF45/RSK-dependent regulation of gene expression and KSHV progeny virion production. Finally, we show data to support that ORF45 regulates the translational efficiency of a subset of viral/cellular genes with complex secondary structure in their 5’ UTR. Altogether, these data shed light on the mechanisms by which KSHV ORF45 manipulates

  16. Chronic active Epstein-Barr virus infection with marked pericardial effusion successfully treated with allogeneic peripheral blood stem cell transplantation.

    PubMed

    Matsui, Shinichiro; Takeda, Yusuke; Isshiki, Yusuke; Yamazaki, Atsuko; Nakao, Sanshiro; Takaishi, Koji; Nagao, Yuhei; Hasegawa, Nagisa; Togasaki, Emi; Shimizu, Ryoh; Kawajiri, Chika; Sakai, Shio; Mimura, Naoya; Takeuchi, Masahiro; Ohwada, Chikako; Sakaida, Emiko; Iseki, Tohru; Imadome, Ken-Ichi; Nakaseko, Chiaki

    2016-05-01

    A 23-year-old woman presented with a persistent fever and shortness of breath. Computed tomography showed marked pericardial effusion, hepatosplenomegaly, and cervical and mediastinal lymph node swelling. Epstein-Barr virus (EBV) antibody titers were abnormally elevated, and the copy number of EBV-DNA was increased in peripheral blood. Based on these observations, she was diagnosed with chronic active EBV infection (CAEBV). The EBV-infected cells in her peripheral blood were CD4(+)T lymphocytes. Fever and pericardial effusion improved following treatment with a combination of prednisolone, etoposide, and cyclosporine; however, peripheral blood EBV-DNA levels remained high. The patient underwent allogeneic peripheral blood stem cell transplantation from an EBV-seronegative, HLA-matched sibling donor, with fludarabine and melphalan conditioning. The post-transplantation course was uneventful, except for mild skin acute graft-versus-host disease (grade 2). EBV-DNA became undetectable in peripheral blood 98 days post transplantation. She has since been in good health without disease recurrence. CAEBV is a potentially fatal disease caused by persistent EBV infection of T lymphocytes or natural killer cells, thus requiring prompt treatment and allogeneic transplantation. Pericardial effusion is rarely observed in CAEBV and can impede its diagnosis. Therefore, we should be aware that patients may present with marked pericardial effusion as an initial manifestation of CAEBV. PMID:27263789

  17. Lower activation-induced T-cell apoptosis is related to the pathological immune response in secondary infection with hetero-serotype dengue virus.

    PubMed

    Yang, Wang; Yan, Huacheng; Ma, Yuling; Yu, Tiantian; Guo, Hongxia; Kuang, Yuchan; Ren, Ruiwen; Li, Jintao

    2016-03-01

    The available evidence suggests that dengue virus-specific T lymphocytes and cytokine storm play a pivotal role in the immunopathogenesis of plasma leakage. Investigations are underway to identify the immune profiles associated with increased or decreased risk for severe disease. In this study, CD14+ cells from the peripheral blood mononuclear cells (PBMCs) of patients who recovered from DENV-1 infection were infected with DENV-1 or DENV-2 and co-cultured with memory T cells. We found that secondary infection with DENV-2 suppresses the cell reproductive capacity but forms more cell clones and more functional cells to produce more proinflammatory factors (IFN-γ, TNF-α, IL-6, IL-8, IL-12 and IL-17) and less regulatory cytokines (IL-10, TGF-β) which results in higher viral replication compared to secondary infection with DENV-1. Memory dengue virus-specific T cells which are induced in a primary dengue virus infection are reactivated by the heterologous serotype of dengue virus and antigen-presenting cells (APCs) during a secondary infection. Dramatically, less apoptosis and more continuous activation of T cells in secondary infection with hetero-serotype DENV were observed. This discovery which has not been reported previously may be the reasonable and vital interpretation for the cytokine storm and severe symptoms observed in secondary infection with DENV. In summary, secondary infection with hetero-serotype DENV elicits the relatively pathological immune response while secondary infection with homologous-serotype DENV induces the relatively protective immune response by activation-induced cell death (AICD) of T cells.

  18. Expression and characterization of biologically active human hepatocyte growth factor (HGF) by insect cells infected with HGF-recombinant baculovirus.

    PubMed

    Yee, C J; DeFrances, M C; Bell, A; Bowen, W; Petersen, B; Michalopoulos, G K; Zarnegar, R

    1993-08-10

    A cDNA containing the entire coding sequence of human hepatocyte growth factor (HGF) [also known as scatter factor (SF)] was inserted into the genome of Autographa california nuclear polyhedrosis virus (baculovirus) adjacent to the polyhedrin promoter by homologous recombination. Insect cells (Spodoptera frugiperda) infected with the recombinant virus secrete relatively high levels (3-8 mg/L) of biologically active HGF into the culture medium. The recombinant HGF induces pronounced morphological changes and scattering of primary cultures of rat, mouse, and human hepatocytes within 24 h after plating and stimulates DNA synthesis in these cells with the same magnitude as native HGF derived from human placenta or rabbit serum. The human recombinant HGF produced by the insect cells is N-glycosylated, binds to heparin like native HGF, and is recognized by polyclonal antiserums raised against human or rabbit HGF as assessed by immunoblot, ELISA, and immunoneutralization experiments. Metabolic radiolabeling with L-[35S]methionine (pulse-chase experiments) as well as Western blot analysis indicates that the recombinant HGF is synthesized and secreted by the infected insect cells as the unprocessed single-chain form (pro-HGF) when the cells are cultured in serum-free medium. However, when the infected insect cells are cultured in insect culture medium (Grace's medium) containing fetal bovine serum, the secreted HGF is present mainly in the mature heterodimeric form. Addition of serum to the baculovirus-expressed single-chain [125I]HGF in a cell-free system results in conversion to the heterodimeric two-chain form, and the activation is prevented by the serine protease inhibitor PMSF. Incubation of 125I-labeled pro-HGF with rat liver or spleen extracts resulted in conversion of pro-HGF to the heterodimeric two-chain form. A truncated form of HGF containing the N-terminal portion of HGF (kringles 1-3) was also produced in the same expression system. This deleted HGF, by

  19. Transcription factor AP-1 in esophageal squamous cell carcinoma: Alterations in activity and expression during Human Papillomavirus infection

    PubMed Central

    2009-01-01

    Background Esophageal squamous cell carcinoma (ESCC) is a leading cause of cancer-related deaths in Jammu and Kashmir (J&K) region of India. A substantial proportion of esophageal carcinoma is associated with infection of high-risk HPV type 16 and HPV18, the oncogenic expression of which is controlled by host cell transcription factor Activator Protein-1 (AP-1). We, therefore, have investigated the role of DNA binding and expression pattern of AP-1 in esophageal cancer with or without HPV infection. Methods Seventy five histopathologically-confirmed esophageal cancer and an equal number of corresponding adjacent normal tissue biopsies from Kashmir were analyzed for HPV infection, DNA binding activity and expression of AP-1 family of proteins by PCR, gel shift assay and immunoblotting respectively. Results A high DNA binding activity and elevated expression of AP-1 proteins were observed in esophageal cancer, which differed between HPV positive (19%) and HPV negative (81%) carcinomas. While JunB, c-Fos and Fra-1 were the major contributors to AP-1 binding activity in HPV negative cases, Fra-1 was completely absent in HPV16 positive cancers. Comparison of AP-1 family proteins demonstrated high expression of JunD and c-Fos in HPV positive tumors, but interestingly, Fra-1 expression was extremely low or nil in these tumor tissues. Conclusion Differential AP-1 binding activity and expression of its specific proteins between HPV - positive and HPV - negative cases indicate that AP-1 may play an important role during HPV-induced esophageal carcinogenesis. PMID:19758438

  20. Caspase-8 activity prevents type 2 cytokine responses and is required for protective T cell-mediated immunity against Trypanosoma cruzi infection.

    PubMed

    Silva, Elisabeth M; Guillermo, Landi V C; Ribeiro-Gomes, Flávia L; De Meis, Juliana; Pereira, Renata M S; Wu, Zhengqi; Calegari-Silva, Teresa C; Seabra, Sérgio H; Lopes, Ulisses G; Siegel, Richard M; Dosreis, George A; Lopes, Marcela F

    2005-05-15

    During Trypanosoma cruzi infection, T cells up-regulate caspase-8 activity. To assess the role of caspase-8 in T cell-mediated immunity, we investigated the effects of caspase-8 inhibition on T cells in viral FLIP (v-FLIP) transgenic mice. Compared with wild-type controls, increased parasitemia was observed in v-FLIP mice infected with T. cruzi. There was a profound decrease in expansion of both CD4 and CD8 T cell subsets in the spleens of infected v-FLIP mice. We did not find differences in activation ratios of T cells from transgenic or wild-type infected mice. However, the numbers of memory/activated CD4 and CD8 T cells were markedly reduced in v-FLIP mice, possibly due to defective survival. We also found decreased production of IL-2 and increased secretion of type 2 cytokines, IL-4 and IL-10, which could enhance susceptibility to infection. Similar, but less pronounced, alterations were observed in mice treated with the caspase-8 inhibitor, zIETD. Furthermore, blockade of caspase-8 by zIETD in vitro mimicked the effects observed on T. cruzi infection in vivo, affecting the generation of activated/memory T cells and T cell cytokine production. Caspase-8 is also required for NF-kappaB signaling upon T cell activation. Blockade of caspase-8 by either v-FLIP expression or treatment with zIETD peptide decreased NF-kappaB responses to TCR:CD3 engagement in T cell cultures. These results suggest a critical role for caspase-8 in the establishment of T cell memory, cell signaling, and regulation of cytokine responses during protozoan infection.

  1. Lysis of HIV-1 Infected Autologous CD4+ Primary T cells by Interferon-alpha Activated NK cells Requires NKp46 and NKG2D

    PubMed Central

    Tomescu, Costin; Mavilio, Domenico; Montaner, Luis J.

    2015-01-01

    Objective Autologous HIV-1 infected CD4+ primary T cells (aHIV+CD4) have been shown to be largely resistant to Natural Killer (NK) cell mediated lysis due to viral strategies of immune evasion. We have previously shown that a pre-activation of NK cells with Plasmacytoid Dendritic Cells can significantly augment lysis of aHIV+CD4 through a mechanism dependent on Interferon-alpha (IFN-α). Design The goal of the present study is to identify the specific NK activating receptors involved in NK lysis of aHIV+CD4 following IFN-α activation. Methods PBMC were incubated with aHIV+CD4 to induce the secretion of endogenous levels of IFN-α and drive NK activation. We then utilized a standard chromium lysis assay to assess the degree of IFN-α activated lysis of aHIV+CD4 in the presence or absence of masking antibodies to a panel of NK activating receptors and co-receptors. Results Direct recognition of HIV-1 infected, but not uninfected, autologous CD4+ primary T cells by PBMC induced the secretion IFN-α (Median 2280 pg/ml, p<0.001, n=9) that, in turn, activated NK cells (p<0.001, n=12) and significantly increased their cytolytic potential against aHIV+CD4 (p<0.01, n=12). The masking of NKp46 (p<0.01, n=8) and NKG2D (p<0.05, n=8), but not 2B4, NTBA, NKp30 or NKp44, significantly reduced IFN-α activated lysis of aHIV+CD4. Conclusions Taken together, these results demonstrate that endogenous levels of IFN-α secreted by pDCs induce NK cells to lyse aHIV+CD4 via the engagement of NKp46 and NKG2D. PMID:26372382

  2. In-cell infection: a novel pathway for Epstein-Barr virus infection mediated by cell-in-cell structures

    PubMed Central

    Ni, Chao; Chen, Yuhui; Zeng, Musheng; Pei, Rongjuan; Du, Yong; Tang, Linquan; Wang, Mengyi; Hu, Yazhuo; Zhu, Hanyu; He, Meifang; Wei, Xiawei; Wang, Shan; Ning, Xiangkai; Wang, Manna; Wang, Jufang; Ma, Li; Chen, Xinwen; Sun, Qiang; Tang, Hong; Wang, Ying; Wang, Xiaoning

    2015-01-01

    Epstein-Barr virus (EBV) can infect both susceptible B lymphocytes and non-susceptible epithelial cells (ECs). Viral tropism analyses have revealed two intriguing means of EBV infection, either by a receptor-mediated infection of B cells or by a cell-to-cell contact-mediated infection of non-susceptible ECs. Herein, we report a novel “in-cell infection” mechanism for EBV infection of non-susceptible ECs through the formation of cell-in-cell structures. Epithelial CNE-2 cells were invaded by EBV-infected Akata B cells to form cell-in-cell structures in vitro. Such unique cellular structures could be readily observed in the specimens of nasopharyngeal carcinoma. Importantly, the formation of cell-in-cell structures led to the autonomous activation of EBV within Akata cells and subsequent viral transmission to CNE-2 cells, as evidenced by the expression of viral genes and the presence of virion particles in CNE-2 cells. Significantly, EBV generated from in-cell infected ECs displayed altered tropism with higher infection efficacy to both B cells and ECs. In addition to CNE-2 tumor cells, cell-in-cell structure formation could also mediate EBV infection of NPEC1-Bmi1 cells, an immortalized nasopharyngeal epithelial cell line. Furthermore, efficient infection by this mechanism involved the activation of the PI3K/AKT signaling pathway. Thus, our study identified “in-cell infection” as a novel mechanism for EBV infection. Given the diversity of virus-infected cells and the prevalence of cell-in-cell structures during chronic infection, we speculate that “in-cell infection” is likely a general mechanism for EBV and other viruses to infect non-susceptible ECs. PMID:25916549

  3. Trypanosoma cruzi Infection Modulates In Vivo Expression of Major Histocompatibility Complex Class II Molecules on Antigen-Presenting Cells and T-Cell Stimulatory Activity of Dendritic Cells in a Strain-Dependent Manner

    PubMed Central

    Alba Soto, Catalina D.; Mirkin, Gerardo A.; Solana, Maria E.; González Cappa, Stella M.

    2003-01-01

    A striking feature of Chagas' disease is the diversity of clinical presentations. Such variability may be due to the heterogeneity among Trypanosoma cruzi isolates or to the host immune response. Employing two strains which differ in their virulence, we investigated the effect of in vivo infection on professional antigen-presenting cells (APC). Acute infection with the virulent RA strain downregulated the expression of major histocompatibility complex (MHC) class II on splenic dendritic cells (DC) and inhibited its induction on peritoneal macrophages and splenic B cells. It also impaired the ability of DC to prime allogeneic T cells and to form homotypic clusters, suggesting a low maturation state of these cells. In contrast, the low-virulence K98 strain maintained the expression of MHC class II on DC or stimulated it on peritoneal macrophages and B cells and preserved DC's T-cell priming capacity and homotypic clustering. DC from RA-infected mice elicited a lower activation of T. cruzi-specific T-cell proliferation than those from K98-infected mice. APC from RA-infected mice that reached the chronic phase of infection restored MHC class II levels to those found in K98-infected mice and upregulated costimulatory molecules expression, suggesting that the immunosuppression caused by this strain is only transient. Taken together, the results indicate that in vivo infection with T. cruzi modulates APC functionality and that this is accomplished in a strain-dependent manner. PMID:12595432

  4. Activation of hypoxia-inducible factor 1 in human T-cell leukaemia virus type 1-infected cell lines and primary adult T-cell leukaemia cells

    PubMed Central

    Tomita, Mariko; Semenza, Gregg L.; Michiels, Canine; Matsuda, Takehiro; Uchihara, Jun-Nosuke; Okudaira, Taeko; Tanaka, Yuetsu; Taira, Naoya; Ohshiro, Kazuiku; Mori, Naoki

    2007-01-01

    HTLV-1 (human T-cell leukaemia virus type 1) is the causative agent for ATL (adult T-cell leukaemia). HTLV-1 Tax can activate the PI3K (phosphoinositide 3-kinase)/Akt signalling pathway, which is responsible for survival of HTLV-1-infected T-cells. HIFs (hypoxia-inducible factors) are transcriptional regulators that play a central role in the response to hypoxia. Overexpression of HIF-1α in many cancers is associated with a poor response to treatment and increased patient mortality. Our objectives in the present study were to investigate whether HIF-1 was activated in HTLV-1-infected T-cells and to elucidate the molecular mechanisms of HIF-1 activation by focusing on the PI3K/Akt signalling pathway. We detected a potent pathway that activated HIF-1 in the HTLV-1-infected T-cells under a normal oxygen concentration. Enhanced HIF-1α protein expression and HIF-1 DNA-binding activity were exhibited in HTLV-1-infected T-cell lines. Knockdown of HIF-1α by siRNA (small interfering RNA) suppressed the growth and VEGF (vascular endothelial growth factor) expression of the HTLV-1-infected T-cell line. HIF-1 protein accumulation and transcriptional activity were enhanced by Tax, which was inhibited by dominant-negative Akt. Importantly, mutant forms of Tax that are defective in activation of the PI3K/Akt pathway failed to induce HIF-1 transcriptional activity. The PI3K inhibitor LY294002 suppressed HIF-1α protein expression, HIF-1 DNA-binding and HIF-1 transcriptional activity in HTLV-1-infected T-cell lines. In primary ATL cells, HIF-1α protein levels were strongly correlated with levels of phosphorylated Akt. The results of the present study suggest that PI3K/Akt activation induced by Tax leads to activation of HIF-1. As HIF-1 plays a major role in tumour progression, it may represent a molecular target for the development of novel ATL therapeutics. PMID:17576198

  5. Physical activity, immunity and infection.

    PubMed

    Romeo, J; Wärnberg, J; Pozo, T; Marcos, A

    2010-08-01

    During the last few decades, scientific evidence has confirmed a wide range of health benefits related to regular physical activity. How physical activity affects the immune function and infection risk is, however, still under debate. Commonly, intensive exercise suppresses the activity and levels of several immune cells, while other immune functions may be stimulated by moderate physical activity. With this knowledge, the understanding of the relationship between different levels of physical activity on the immune function has been raised as a potential tool to protect health not only in athletes but also in the general population; the mechanisms that translate a physically active lifestyle into good health continue to be investigated. Reviewing the literature, although several outcomes (i.e. the mechanisms by which different levels and duration of physical activity programmes affect numerous cell types and responses) remain unclear, given that the additional benefits encompass healthy habits including exercise, the use of physical activity programmes may result in improved health of elderly populations. Moderate physical activity or moderate-regulated training may enhance the immune function mainly in less fit subjects or sedentary population and the pre-event fitness status also seems to be an important individual factor regarding this relationship. Although adequate nutrition and regular physical activity habits may synergistically improve health, clinical trials in athletes using nutritional supplements to counteract the immune suppression have been inconclusive so far.Further research is necessary to find out to what extent physical activity training can exert an effect on the immune function.

  6. An active intracellular device to prevent lethal disease outcomes in virus-infected bacterial cells.

    PubMed

    Bagh, Sangram; Mandal, Mahuya; Ang, Jordan; McMillen, David R

    2011-03-01

    Synthetic biology includes an effort to logically control cellular behavior. One long-term goal is to implement medical interventions inside living cells, creating intracellular "disease fighters"; one may imagine a system that detects viral infection and responds to halt the spread of the virus. Here, we explore a system designed to display some of the qualitative features that such disease prevention systems should have, while not claiming that the system itself has any medical application. An intracellular disease prevention mechanism should: lie dormant in the absence of the disease state; detect the onset of a lethal disease pathway; respond to halt or mitigate the disease's effects; and be subject to external deactivation when required. We have created a device that displays these properties, in the highly simplified case of a bacterial viral disease. Our system detects the onset of the lytic phase of bacteriophage lambda in Escherichia coli, responds by preventing this lethal pathway from being followed, and is deactivated by a temperature shift. We have formulated a mathematical model of the engineered system, using parameters obtained from the literature and by local experimental measurement, and shown that the model captures the essential experimental behavior of the system in most parameter regimes.

  7. Induction of interleukin-8 production via nuclear factor-kappaB activation in human intestinal epithelial cells infected with Vibrio vulnificus.

    PubMed

    Lee, B C; Kim, S H; Choi, S H; Kim, T S

    2005-08-01

    Vibrio vulnificus, a Gram-negative estuarine bacterium, is a causative agent of food-borne diseases, such as life-threatening septicaemia and wound infection disease. V. vulnificus penetrating into the epithelial barrier stimulates an inflammatory response in the adjacent mucosa. Therefore, interaction between V. vulnificus and epithelial cells is important for understanding of both the immunology of mucosal surfaces and V. vulnificus. In this study, we investigated the effect and action mechanism of V. vulnificus infection on production of interleukin (IL)-8, a proinflammatory cytokine, in human intestinal epithelial INT-407 cells. V. vulnificus infection significantly induced IL-8 production in a time- and multiplicity of infection (MOI)-dependent manner, as determined by human IL-8 enzyme-linked immunosorbent assay (ELISA). In addition, V. vulnificus infection significantly increased IL-8 mRNA levels in INT-407 cells, indicating that the increased IL-8 production by V. vulnificus occurred at the transcriptional level. V. vulnificus infection also enhanced IL-8 gene promoter activity in INT-407 cells transiently transfected with IL-8 promoter constructs, but this effect was impaired in INT-407 cells transfected with IL-8 promoter constructs deleted or mutated of a kappaB site. V. vulnificus infection increased the nuclear factor-kappaB (NF-kappaB) binding activity to a kappaB site and the degradation of IkappaB-alpha protein in a time- and a MOI-dependent manner. Furthermore, BAY11-7082, an inhibitor of NF-kappaB activation, significantly reduced the IL-8 production, NF-kappaB binding activity and IkappaB-alpha degradation induced by V. vulnificus infection. Taken together, these results indicate clearly that V. vulnificus infection significantly induces IL-8 production in human intestinal epithelial cells via NF-kappaB activation.

  8. Identification of candidate agents active against N. ceranae infection in honey bees: establishment of a medium throughput screening assay based on N. ceranae infected cultured cells.

    PubMed

    Gisder, Sebastian; Genersch, Elke

    2015-01-01

    Many flowering plants in both natural ecosytems and agriculture are dependent on insect pollination for fruit set and seed production. Managed honey bees (Apis mellifera) and wild bees are key pollinators providing this indispensable eco- and agrosystem service. Like all other organisms, bees are attacked by numerous pathogens and parasites. Nosema apis is a honey bee pathogenic microsporidium which is widely distributed in honey bee populations without causing much harm. Its congener Nosema ceranae was originally described as pathogen of the Eastern honey bee (Apis cerana) but jumped host from A. cerana to A. mellifera about 20 years ago and spilled over from A. mellifera to Bombus spp. quite recently. N. ceranae is now considered a deadly emerging parasite of both Western honey bees and bumblebees. Hence, novel and sustainable treatment strategies against N. ceranae are urgently needed to protect honey and wild bees. We here present the development of an in vitro medium throughput screening assay for the identification of candidate agents active against N. ceranae infections. This novel assay is based on our recently developed cell culture model for N. ceranae and coupled with an RT-PCR-ELISA protocol for quantification of N. ceranae in infected cells. The assay has been adapted to the 96-well microplate format to allow automated analysis. Several substances with known (fumagillin) or presumed (surfactin) or no (paromomycin) activity against N. ceranae were tested as well as substances for which no data concerning N. ceranae inhibition existed. While fumagillin and two nitroimidazoles (metronidazole, tinidazole) totally inhibited N. ceranae proliferation, all other test substances were inactive. In summary, the assay proved suitable for substance screening and demonstrated the activity of two synthetic antibiotics against N. ceranae.

  9. Identification of candidate agents active against N. ceranae infection in honey bees: establishment of a medium throughput screening assay based on N. ceranae infected cultured cells.

    PubMed

    Gisder, Sebastian; Genersch, Elke

    2015-01-01

    Many flowering plants in both natural ecosytems and agriculture are dependent on insect pollination for fruit set and seed production. Managed honey bees (Apis mellifera) and wild bees are key pollinators providing this indispensable eco- and agrosystem service. Like all other organisms, bees are attacked by numerous pathogens and parasites. Nosema apis is a honey bee pathogenic microsporidium which is widely distributed in honey bee populations without causing much harm. Its congener Nosema ceranae was originally described as pathogen of the Eastern honey bee (Apis cerana) but jumped host from A. cerana to A. mellifera about 20 years ago and spilled over from A. mellifera to Bombus spp. quite recently. N. ceranae is now considered a deadly emerging parasite of both Western honey bees and bumblebees. Hence, novel and sustainable treatment strategies against N. ceranae are urgently needed to protect honey and wild bees. We here present the development of an in vitro medium throughput screening assay for the identification of candidate agents active against N. ceranae infections. This novel assay is based on our recently developed cell culture model for N. ceranae and coupled with an RT-PCR-ELISA protocol for quantification of N. ceranae in infected cells. The assay has been adapted to the 96-well microplate format to allow automated analysis. Several substances with known (fumagillin) or presumed (surfactin) or no (paromomycin) activity against N. ceranae were tested as well as substances for which no data concerning N. ceranae inhibition existed. While fumagillin and two nitroimidazoles (metronidazole, tinidazole) totally inhibited N. ceranae proliferation, all other test substances were inactive. In summary, the assay proved suitable for substance screening and demonstrated the activity of two synthetic antibiotics against N. ceranae. PMID:25658121

  10. Identification of Candidate Agents Active against N. ceranae Infection in Honey Bees: Establishment of a Medium Throughput Screening Assay Based on N. ceranae Infected Cultured Cells

    PubMed Central

    Gisder, Sebastian; Genersch, Elke

    2015-01-01

    Many flowering plants in both natural ecosytems and agriculture are dependent on insect pollination for fruit set and seed production. Managed honey bees (Apis mellifera) and wild bees are key pollinators providing this indispensable eco- and agrosystem service. Like all other organisms, bees are attacked by numerous pathogens and parasites. Nosema apis is a honey bee pathogenic microsporidium which is widely distributed in honey bee populations without causing much harm. Its congener Nosema ceranae was originally described as pathogen of the Eastern honey bee (Apis cerana) but jumped host from A. cerana to A. mellifera about 20 years ago and spilled over from A. mellifera to Bombus spp. quite recently. N. ceranae is now considered a deadly emerging parasite of both Western honey bees and bumblebees. Hence, novel and sustainable treatment strategies against N. ceranae are urgently needed to protect honey and wild bees. We here present the development of an in vitro medium throughput screening assay for the identification of candidate agents active against N. ceranae infections. This novel assay is based on our recently developed cell culture model for N. ceranae and coupled with an RT-PCR-ELISA protocol for quantification of N. ceranae in infected cells. The assay has been adapted to the 96-well microplate format to allow automated analysis. Several substances with known (fumagillin) or presumed (surfactin) or no (paromomycin) activity against N. ceranae were tested as well as substances for which no data concerning N. ceranae inhibition existed. While fumagillin and two nitroimidazoles (metronidazole, tinidazole) totally inhibited N. ceranae proliferation, all other test substances were inactive. In summary, the assay proved suitable for substance screening and demonstrated the activity of two synthetic antibiotics against N. ceranae. PMID:25658121

  11. Activation of NF-κB and AP-1 Mediates Hyperproliferation by Inducing β-Catenin and c-Myc in Helicobacter pylori-Infected Gastric Epithelial Cells

    PubMed Central

    Byun, Eunyoung; Park, Bohye; Lim, Joo Weon

    2016-01-01

    Purpose In the gastric mucosa of Helicobacter pylori (H. pylori)-infected patients with gastritis or adenocarcinoma, proliferation of gastric epithelial cells is increased. Hyperproliferation is related to induction of oncogenes, such as β-catenin and c-myc. Even though transcription factors NF-κB and AP-1 are activated in H. pylori-infected cells, whether NF-κB or AP-1 regulates the expression of β-catenein or c-myc in H. pylori-infected cells has not been clarified. The present study was undertaken to investigate whether H. pylori-induced activation of NF-κB and AP-1 mediates the expression of oncogenes and hyperproliferation of gastric epithelial cells. Materials and Methods Gastric epithelial AGS cells were transiently transfected with mutant genes for IκBα (MAD3) and c-Jun (TAM67) or treated with a specific NF-κB inhibitor caffeic acid phenethyl ester (CAPE) or a selective AP-1 inhibitor SR-11302 to suppress activation of NF-κB or AP-1, respecively. As reference cells, the control vector pcDNA was transfected to the cells. Wild-type cells or transfected cells were cultured with or without H. pylori. Results H. pylori induced activation of NF-κB and AP-1, cell proliferation, and expression of oncogenes (β-catenein, c-myc) in AGS cells, which was inhibited by transfection of MAD3 and TAM67. Wild-type cells and the cells transfected with pcDNA showed similar activities of NF-κB and AP-1, proliferation, and oncogene expression regardless of treatment with H. pylori. Both CAPE and SR-11302 inhibited cell proliferation and expression of oncogenes in H. pylori-infected cells. Conclusion H. pylori-induced activation of NF-κB and AP-1 regulates transcription of oncogenes and mediates hyperproliferation in gastric epithelial cells. PMID:26996564

  12. T cell anergy and activation are associated with suboptimal humoral responses to measles revaccination in HIV-infected children on anti-retroviral therapy in Nairobi, Kenya.

    PubMed

    Buechler, M B; Newman, L P; Chohan, B H; Njoroge, A; Wamalwa, D; Farquhar, C

    2015-09-01

    HIV-infected children are less capable of mounting and maintaining protective humoral responses to vaccination against measles compared to HIV-uninfected children. This poses a public health challenge in countries with high HIV burdens. Administration of anti-retroviral therapy (ART) and revaccinating children against measles is one approach to increase measles immunity in HIV-infected children, yet it is not effective in all cases. Immune anergy and activation during HIV infection are factors that could influence responses to measles revaccination. We utilized a flow cytometry-based approach to examine whether T cell anergy and activation were associated with the maintenance of measles-specific immunoglobulin (Ig)G antibodies generated in response to measles revaccination in a cohort of HIV-infected children on ART in Nairobi, Kenya. Children who sustained measles-specific IgG for at least 1 year after revaccination displayed significantly lower programmed cell death 1 (PD-1) surface expression on CD8(+) T cells on a per-cell basis and exhibited less activated CD4(+) T cells compared to those unable to maintain detectable measles-specific antibodies. Children in both groups were similar in age and sex, CD4(+) T cell frequency, duration of ART treatment and HIV viral load at enrolment. These data suggest that aberrant T cell anergy and activation are associated with the impaired ability to sustain an antibody response to measles revaccination in HIV-infected children on ART. PMID:25739813

  13. Modeling the effects of vorinostat in vivo reveals both transient and delayed HIV transcriptional activation and minimal killing of latently infected cells

    SciTech Connect

    Ke, Ruian; Lewin, Sharon R.; Elliott, Julian H.; Perelson, Alan S.; Chakraborty, Arup K.

    2015-10-23

    Recent efforts to cure human immunodeficiency virus type-1 (HIV-1) infection have focused on developing latency reversing agents as a first step to eradicate the latent reservoir. The histone deacetylase inhibitor, vorinostat, has been shown to activate HIV RNA transcription in CD4+ T-cells and alter host cell gene transcription in HIV-infected individuals on antiretroviral therapy. In order to understand how latently infected cells respond dynamically to vorinostat treatment and determine the impact of vorinostat on reservoir size in vivo, we have constructed viral dynamic models of latency that incorporate vorinostat treatment. We fitted these models to data collected from a recent clinical trial in which vorinostat was administered daily for 14 days to HIV-infected individuals on suppressive ART. The results show that HIV transcription is increased transiently during the first few hours or days of treatment and that there is a delay before a sustained increase of HIV transcription, whose duration varies among study participants and may depend on the long term impact of vorinostat on host gene expression. Parameter estimation suggests that in latently infected cells, HIV transcription induced by vorinostat occurs at lower levels than in productively infected cells. Lastly, the estimated loss rate of transcriptionally induced cells remains close to baseline in most study participants, suggesting vorinostat treatment does not induce latently infected cell killing and thus reduce the latent reservoir in vivo.

  14. Modeling the effects of vorinostat in vivo reveals both transient and delayed HIV transcriptional activation and minimal killing of latently infected cells

    DOE PAGES

    Ke, Ruian; Lewin, Sharon R.; Elliott, Julian H.; Perelson, Alan S.; Chakraborty, Arup K.

    2015-10-23

    Recent efforts to cure human immunodeficiency virus type-1 (HIV-1) infection have focused on developing latency reversing agents as a first step to eradicate the latent reservoir. The histone deacetylase inhibitor, vorinostat, has been shown to activate HIV RNA transcription in CD4+ T-cells and alter host cell gene transcription in HIV-infected individuals on antiretroviral therapy. In order to understand how latently infected cells respond dynamically to vorinostat treatment and determine the impact of vorinostat on reservoir size in vivo, we have constructed viral dynamic models of latency that incorporate vorinostat treatment. We fitted these models to data collected from a recentmore » clinical trial in which vorinostat was administered daily for 14 days to HIV-infected individuals on suppressive ART. The results show that HIV transcription is increased transiently during the first few hours or days of treatment and that there is a delay before a sustained increase of HIV transcription, whose duration varies among study participants and may depend on the long term impact of vorinostat on host gene expression. Parameter estimation suggests that in latently infected cells, HIV transcription induced by vorinostat occurs at lower levels than in productively infected cells. Lastly, the estimated loss rate of transcriptionally induced cells remains close to baseline in most study participants, suggesting vorinostat treatment does not induce latently infected cell killing and thus reduce the latent reservoir in vivo.« less

  15. Modeling the Effects of Vorinostat In Vivo Reveals both Transient and Delayed HIV Transcriptional Activation and Minimal Killing of Latently Infected Cells.

    PubMed

    Ke, Ruian; Lewin, Sharon R; Elliott, Julian H; Perelson, Alan S

    2015-10-01

    Recent efforts to cure human immunodeficiency virus type-1 (HIV-1) infection have focused on developing latency reversing agents as a first step to eradicate the latent reservoir. The histone deacetylase inhibitor, vorinostat, has been shown to activate HIV RNA transcription in CD4+ T-cells and alter host cell gene transcription in HIV-infected individuals on antiretroviral therapy. In order to understand how latently infected cells respond dynamically to vorinostat treatment and determine the impact of vorinostat on reservoir size in vivo, we have constructed viral dynamic models of latency that incorporate vorinostat treatment. We fitted these models to data collected from a recent clinical trial in which vorinostat was administered daily for 14 days to HIV-infected individuals on suppressive ART. The results show that HIV transcription is increased transiently during the first few hours or days of treatment and that there is a delay before a sustained increase of HIV transcription, whose duration varies among study participants and may depend on the long term impact of vorinostat on host gene expression. Parameter estimation suggests that in latently infected cells, HIV transcription induced by vorinostat occurs at lower levels than in productively infected cells. Furthermore, the estimated loss rate of transcriptionally induced cells remains close to baseline in most study participants, suggesting vorinostat treatment does not induce latently infected cell killing and thus reduce the latent reservoir in vivo.

  16. Modeling the Effects of Vorinostat In Vivo Reveals both Transient and Delayed HIV Transcriptional Activation and Minimal Killing of Latently Infected Cells

    PubMed Central

    Ke, Ruian; Lewin, Sharon R.; Elliott, Julian H; Perelson, Alan S.

    2015-01-01

    Recent efforts to cure human immunodeficiency virus type-1 (HIV-1) infection have focused on developing latency reversing agents as a first step to eradicate the latent reservoir. The histone deacetylase inhibitor, vorinostat, has been shown to activate HIV RNA transcription in CD4+ T-cells and alter host cell gene transcription in HIV-infected individuals on antiretroviral therapy. In order to understand how latently infected cells respond dynamically to vorinostat treatment and determine the impact of vorinostat on reservoir size in vivo, we have constructed viral dynamic models of latency that incorporate vorinostat treatment. We fitted these models to data collected from a recent clinical trial in which vorinostat was administered daily for 14 days to HIV-infected individuals on suppressive ART. The results show that HIV transcription is increased transiently during the first few hours or days of treatment and that there is a delay before a sustained increase of HIV transcription, whose duration varies among study participants and may depend on the long term impact of vorinostat on host gene expression. Parameter estimation suggests that in latently infected cells, HIV transcription induced by vorinostat occurs at lower levels than in productively infected cells. Furthermore, the estimated loss rate of transcriptionally induced cells remains close to baseline in most study participants, suggesting vorinostat treatment does not induce latently infected cell killing and thus reduce the latent reservoir in vivo. PMID:26496627

  17. The virion host shutoff RNase plays a key role in blocking the activation of protein kinase R in cells infected with herpes simplex virus 1.

    PubMed

    Sciortino, Maria Teresa; Parisi, Tiziana; Siracusano, Gabriel; Mastino, Antonio; Taddeo, Brunella; Roizman, Bernard

    2013-03-01

    Earlier studies have shown that active MEK blocks the activation of protein kinase R (PKR), a component of antiviral innate immune responses. In this report we show that the herpes simplex virus 1 virion host shutoff (VHS) RNase protein and MEK (mitogen-activated protein kinase kinase) act cooperatively in blocking the activation of PKR. This conclusion is based on the following. (i) In contrast to viral gene expression in the parental cell line or a cell line expressing a constitutively active MEK, the replication of a VHS mutant is particularly impaired in cells expressing dominant negative MEK. In this cell line PKR is activated by phosphorylation, and the accumulation of several viral proteins is delayed. (ii) In transfected cells, wild-type VHS blocked the activation of PKR, whereas PKR was activated in cells transfected with a mutant VHS or with plasmids encoding the VHS RNase and VP16 and VP22, the two viral proteins that neutralize the RNase activity of VHS. The results suggest that early in infection the VHS RNase degrades RNAs that activate PKR. Coupled with published data, the results suggest that inhibition of activation of PKR or its effect on viral replication is staged early in infection by VHS, postsynthesis of VP16 and VP22 by the γ(1)34.5 protein, and very late in infection by the U(S)11 protein.

  18. Fluorescence Activated Cell Sorting of Rickettsia prowazekii-Infected Host Cells Based on Bacterial Burden and Early Detection of Fluorescent Rickettsial Transformants

    PubMed Central

    Driskell, Lonnie O.; Tucker, Aimee M.; Woodard, Andrew; Wood, Raphael R.; Wood, David O.

    2016-01-01

    Rickettsia prowazekii, the causative agent of epidemic typhus, is an obligate intracellular bacterium that replicates only within the cytosol of a eukaryotic host cell. Despite the barriers to genetic manipulation that such a life style creates, rickettsial mutants have been generated by transposon insertion as well as by homologous recombination mechanisms. However, progress is hampered by the length of time required to identify and isolate R. prowazekii transformants. To reduce the time required and variability associated with propagation and harvesting of rickettsiae for each transformation experiment, characterized frozen stocks were used to generate electrocompetent rickettsiae. Transformation experiments employing these rickettsiae established that fluorescent rickettsial populations could be identified using a fluorescence activated cell sorter within one week following electroporation. Early detection was improved with increasing amounts of transforming DNA. In addition, we demonstrate that heterogeneous populations of rickettsiae-infected cells can be sorted into distinct sub-populations based on the number of rickettsiae per cell. Together our data suggest the combination of fluorescent reporters and cell sorting represent an important technical advance that will facilitate isolation of distinct R. prowazekii mutants and allow for closer examination of the effects of infection on host cells at various infectious burdens. PMID:27010457

  19. Pulmonary paracoccidioidomycosis in resistant and susceptible mice: relationship among progression of infection, bronchoalveolar cell activation, cellular immune response, and specific isotype patterns.

    PubMed Central

    Cano, L E; Singer-Vermes, L M; Vaz, C A; Russo, M; Calich, V L

    1995-01-01

    Using the intraperitoneal route of infection, we demonstrated previously that A/Sn mice are resistant and B10.A mice are susceptible to Paracoccidioides brasiliensis infection. Since paracoccidioidomycosis is a deep systemic granulomatous disorder that involves primarily the lungs and then disseminates to other organs and systems, we herein investigated the course of the infection and the resulting immune responses developed by A/Sn and B10.A mice after intratracheal infection with P. brasiliensis yeast cells. It was observed that A/Sn mice develop a chronic benign pulmonary-restricted infection, whereas B10.A mice present a chronic progressive disseminated disease. A/Sn animals were able to restrict fungal infection to the lungs despite the increased fungal load at the beginning of the infection. This behavior was associated with low mortality rates, the presence of adequate and persistent delayed-type hypersensitivity reactions, oxidative burst by bronchoalveolar cells, and production of high levels of specific antibodies in which immunoglobulin G2a (IgG2a) and IgG3 isotype titers were significantly higher than those observed in the susceptible mice. In contrast, B10.A animals showed a constant pulmonary fungal load and dissemination to the liver and spleen. This infection pattern resulted in high mortality rates, discrete delayed-type hypersensitivity reactivity, poorly activated or nonactivated bronchoalveolar cells, and production of specific IgG2b isotype titers significantly higher than those observed in the resistant mice at week 4 of infection. Thus, A/Sn and B10.A mice maintain the same resistance patterns as those observed previously with the intraperitoneal route of infection. Furthermore, the obtained results suggest that resistance to paracoccidioidomycosis is associated with T-cell, macrophage, and B-cell activities that are known to be mediated by gamma interferon. PMID:7729885

  20. Macrophage-activating T-cell factor(s) produced in an early phase of Legionella pneumophila infection in guinea pigs.

    PubMed Central

    Nikaido, Y; Yoshida, S; Goto, Y; Mizuguchi, Y; Kuroiwa, A

    1989-01-01

    Protective immunity of guinea pigs against Legionella pneumophila was studied by infecting the animals with a sublethal dose (about 2 x 10(4) CFU) of the organism. The bacteria multiplied in the liver, spleen, and lungs up to day 4 after the intraperitoneal infection. The live bacteria in these organs decreased quickly thereafter and were eliminated by day 7. A delayed-type skin reaction and lymphoproliferation of spleen cells to Formalin-killed L. pneumophila were detected from days 5 and 6, respectively, after infection. Peritoneal macrophages obtained from guinea pigs infected 6 days previously inhibited the intracellular growth of L. pneumophila. Antigen-stimulated spleen cell factor prepared from infected guinea pigs inhibited the intracellular growth of the organism in macrophages obtained from uninfected animals. Antigen-stimulated spleen cell factor prepared from spleen cells treated with anti-guinea pig T-cell monoclonal antibody did not inhibit growth. The activity of antigen-stimulated spleen cell factor was labile to pH 2 treatment, and the factor could not be absorbed by L. pneumophila antigen, suggesting that it contains gamma interferon. Our data show that T-cell-mediated immunity begins to work from an early period of infection with L. pneumophila in guinea pigs. PMID:2807531

  1. Bovine natural killer cells are present in Escherichia coli infected mammary gland tissue and show antimicrobial activity in vitro.

    PubMed

    Sipka, Anja; Pomeroy, Brianna; Klaessig, Suzanne; Schukken, Ynte

    2016-10-01

    Natural killer (NK) cells are early responders in bacterial infections but their role in bovine mastitis has not been characterized. For the first time, we show the presence of NK cells (NKp46(+)/CD3(-)) in bovine mammary gland tissue after an intramammary challenge with Escherichia (E.) coli. A small number of NK cells was detected in milk from quarters before and during an E. coli challenge. In vitro cultures of primary bovine mammary gland epithelial cells stimulated with UV irradiated E. coli induced significant migration of peripheral blood NK cells (pbNK) within 2h. Furthermore, pbNK cells significantly reduced counts of live E. coli in vitro within 2h of culture. The results show that bovine NK cells have the capacity to migrate to the site of infection and produce antibacterial mediators. These findings introduce NK cells as a leukocyte population in the mammary gland with potential functions in the innate immune response in bovine mastitis. PMID:27638120

  2. Heligmosomoides polygyrus bakeri infection activates colonic FoxP3+ T cells enhancing their capacity to prevent colitis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Helminthic infections protect mice from colitis in murine models of inflammatory bowel disease and also may protect people. Helminths like Heligmosomoides bakeri (Hpb) can induce Tregs. Experiments explored if Hpb infection could protect mice from colitis through activation of colonic Treg and exam...

  3. Quantitative evaluation of T-cell response after specific antigen stimulation in active and latent tuberculosis infection in adults and children.

    PubMed

    Latorre, Irene; De Souza-Galvão, Malú; Ruiz-Manzano, Juan; Lacoma, Alicia; Prat, Cristina; Fuenzalida, Loreto; Altet, Neus; Ausina, Vicente; Domínguez, Jose

    2009-11-01

    We have evaluated the quantitative T-cell response after specific Mycobacterium tuberculosis antigen stimulation in active tuberculosis (TB) and latent TB infection (LTBI) patients. In adults, the median number of T cells after RD1 antigen stimulation was significantly higher in active TB patients than in LTBI patients. In children, the number of responder T cells against the specific antigens was higher in active TB than in LTBI patients, although the differences were not significant. In summary, in patients with suspected clinical TB, although there is overlapping in the number of responder T cells between both groups, a T-cell count above the described threshold could suggest active TB, especially in patients with a high probability of having active TB and low probability of having LTBI. In addition, the results are consistent with the current evidence that T-cell response may indicate mycobacterial burden and disease activity.

  4. Infection, Stem Cells and Cancer Signals

    PubMed Central

    Sell, S.

    2013-01-01

    The association of cancer with preceding parasitic infections has been observed for over 200 years. Some such cancers arise from infection of tissue stem cells by viruses with insertion of viral oncogenes into the host DNA (mouse polyoma virus, mouse mammary tumor virus). In other cases the virus does not insert its DNA into the host cells, but rather commandeers the metabolism of the infected cells, so that the cells continue to proliferate and do not differentiate (human papilloma virus and cervical cancer). Cytoplasmic Epstein Barr virus infection is associated with a specific gene translocation (Ig/c-myc) that activates proliferation of affected cells (Burkitt lymphoma). In chronic osteomyelitis an inflammatory reaction to the infection appears to act through production of inflammatory cytokines and oxygen radical formation to induce epithelial cancers. Infection with Helicobacter pylori leads to epigenetic changes in methylation and infection by a parasite. Clonorchis sinensis also acts as a promoter of cancer of the bile ducts of the liver (cholaniocarcinoma). The common thread among these diverse pathways is that the infections act to alter tissue stem cell signaling with continued proliferation of tumor transit amplifying cells. PMID:21044009

  5. Activation of Langerhans-Type Dendritic Cells Alters Human Cytomegalovirus Infection and Reactivation in a Stimulus-Dependent Manner

    PubMed Central

    Coronel, Roxanne; Jesus, Desyree M.; Dalle Ore, Lucia; Mymryk, Joe S.; Hertel, Laura

    2016-01-01

    Oral mucosal Langerhans cells (LC) are likely to play important roles in host defense against infection by human cytomegalovirus (CMV). We previously showed that in vitro-differentiated immature LC (iLC) populations contain smaller amounts of infected cells but produce higher yields than mature LC (mLC) cultures, obtained by iLC stimulation with fetal bovine serum (FBS), CD40 ligand (CD40L) and lipopolysaccharide (LPS). Here, we sought to determine if exposure to select stimuli can improve LC permissiveness to infection, if specific components of the mLC cocktail are responsible for lowering viral yields, if this is due to defects in progeny production or release, and if these restrictions are also effective against reactivated virus. None of the stimuli tested extended the proportion of infected cells to 100%, suggesting that the block to infection onset cannot be fully removed. While CD40L and FBS exerted positive effects on viral progeny production per cell, stimulation with LPS alone or in combination with CD40L was detrimental. Reductions in viral titers were not due to defects in progeny release, and the permissive or restrictive intracellular environment established upon exposure to each stimulus appeared to act in a somewhat similar way toward lytic and latent infections. PMID:27683575

  6. Activation of Langerhans-Type Dendritic Cells Alters Human Cytomegalovirus Infection and Reactivation in a Stimulus-Dependent Manner.

    PubMed

    Coronel, Roxanne; Jesus, Desyree M; Dalle Ore, Lucia; Mymryk, Joe S; Hertel, Laura

    2016-01-01

    Oral mucosal Langerhans cells (LC) are likely to play important roles in host defense against infection by human cytomegalovirus (CMV). We previously showed that in vitro-differentiated immature LC (iLC) populations contain smaller amounts of infected cells but produce higher yields than mature LC (mLC) cultures, obtained by iLC stimulation with fetal bovine serum (FBS), CD40 ligand (CD40L) and lipopolysaccharide (LPS). Here, we sought to determine if exposure to select stimuli can improve LC permissiveness to infection, if specific components of the mLC cocktail are responsible for lowering viral yields, if this is due to defects in progeny production or release, and if these restrictions are also effective against reactivated virus. None of the stimuli tested extended the proportion of infected cells to 100%, suggesting that the block to infection onset cannot be fully removed. While CD40L and FBS exerted positive effects on viral progeny production per cell, stimulation with LPS alone or in combination with CD40L was detrimental. Reductions in viral titers were not due to defects in progeny release, and the permissive or restrictive intracellular environment established upon exposure to each stimulus appeared to act in a somewhat similar way toward lytic and latent infections. PMID:27683575

  7. Activation of Langerhans-Type Dendritic Cells Alters Human Cytomegalovirus Infection and Reactivation in a Stimulus-Dependent Manner

    PubMed Central

    Coronel, Roxanne; Jesus, Desyree M.; Dalle Ore, Lucia; Mymryk, Joe S.; Hertel, Laura

    2016-01-01

    Oral mucosal Langerhans cells (LC) are likely to play important roles in host defense against infection by human cytomegalovirus (CMV). We previously showed that in vitro-differentiated immature LC (iLC) populations contain smaller amounts of infected cells but produce higher yields than mature LC (mLC) cultures, obtained by iLC stimulation with fetal bovine serum (FBS), CD40 ligand (CD40L) and lipopolysaccharide (LPS). Here, we sought to determine if exposure to select stimuli can improve LC permissiveness to infection, if specific components of the mLC cocktail are responsible for lowering viral yields, if this is due to defects in progeny production or release, and if these restrictions are also effective against reactivated virus. None of the stimuli tested extended the proportion of infected cells to 100%, suggesting that the block to infection onset cannot be fully removed. While CD40L and FBS exerted positive effects on viral progeny production per cell, stimulation with LPS alone or in combination with CD40L was detrimental. Reductions in viral titers were not due to defects in progeny release, and the permissive or restrictive intracellular environment established upon exposure to each stimulus appeared to act in a somewhat similar way toward lytic and latent infections.

  8. Experimental scrapie in golden Syrian hamsters: temporal comparison of in vitro cell-fusing activity with brain infectivity and histopathological changes.

    PubMed Central

    Moreau-Dubois, M C; Brown, P; Rohwer, R G; Masters, C L; Franko, M; Gajdusek, D C

    1982-01-01

    Golden Syrain hamsters were inoculated intracerebrally with the hamster-adapted 263K strain of scrapie virus, and the evolution of in vitro cell fusing activity induced by brain suspensions was compared with brain infectivity titers and histological changes. Cell-fusing activity abruptly appeared 4 weeks after inoculation, 1 week before the earliest detectable histopathological changes, at an infectivity level of 7.6 log 50% lethal doses per g of brain. Cell-fusing activity was sustained throughout the remaining 4 weeks of the incubation period and the subsequent 1- to 3-week stage of clinical illness but did not increase with the logarithmic progression of infectivity, which reached a level of 11 log 50% lethal doses per g in the agonal stage of disease. Gliosis was most sensitively detected by a monoclonal antibody reacting with astrocyte intermediate filaments in an indirect immunofluorescence test, anticipating histological recognition of gliosis and spongiform change by 1 to 2 weeks. In vitro cell-fusing activity is thus one of the earliest known biological markers (apart from infectivity itself) of experimental scrapie infection. PMID:6809626

  9. Early Gag Immunodominance of the HIV-Specific T-Cell Response during Acute/Early Infection Is Associated with Higher CD8+ T-Cell Antiviral Activity and Correlates with Preservation of the CD4+ T-Cell Compartment

    PubMed Central

    Ghiglione, Yanina; Falivene, Juliana; Socias, María Eugenia; Laufer, Natalia; Coloccini, Romina Soledad; Rodriguez, Ana María; Ruiz, María Julia; Pando, María Ángeles; Giavedoni, Luis David; Cahn, Pedro; Sued, Omar; Salomon, Horacio; Gherardi, María Magdalena

    2013-01-01

    The important role of the CD8+ T-cell response on HIV control is well established. Moreover, the acute phase of infection represents a proper scenario to delineate the antiviral cellular functions that best correlate with control. Here, multiple functional aspects (specificity, ex vivo viral inhibitory activity [VIA] and polyfunctionality) of the HIV-specific CD8+ T-cell subset arising early after infection, and their association with disease progression markers, were examined. Blood samples from 44 subjects recruited within 6 months from infection (primary HIV infection [PHI] group), 16 chronically infected subjects, 11 elite controllers (EC), and 10 healthy donors were obtained. Results indicated that, although Nef dominated the anti-HIV response during acute/early infection, a higher proportion of early anti-Gag T cells correlated with delayed progression. Polyfunctional HIV-specific CD8+ T cells were detected at early time points but did not associate with virus control. Conversely, higher CD4+ T-cell set points were observed in PHI subjects with higher HIV-specific CD8+ T-cell VIA at baseline. Importantly, VIA levels correlated with the magnitude of the anti-Gag cellular response. The advantage of Gag-specific cells may result from their enhanced ability to mediate lysis of infected cells (evidenced by a higher capacity to degranulate and to mediate VIA) and to simultaneously produce IFN-γ. Finally, Gag immunodominance was associated with elevated plasma levels of interleukin 2 (IL-2) and macrophage inflammatory protein 1β (MIP-1β). All together, this study underscores the importance of CD8+ T-cell specificity in the improved control of disease progression, which was related to the capacity of Gag-specific cells to mediate both lytic and nonlytic antiviral mechanisms at early time points postinfection. PMID:23616666

  10. Activated platelet–T-cell conjugates in peripheral blood of patients with HIV infection: coupling coagulation/inflammation and T cells

    PubMed Central

    Green, Samantha A.; Smith, Mindy; Hasley, Rebecca B.; Stephany, David; Harned, Adam; Nagashima, Kunio; Abdullah, Shahed; Pittaluga, Stefania; Imamichi, Tomozumi; Qin, Jing; Rupert, Adam; Ober, Alex; Lane, H. Clifford; Catalfamo, Marta

    2015-01-01

    Background: Despite successfully suppressed viremia by treatment, patients with high levels of biomarkers of coagulation/inflammation are at an increased risk of developing non-AIDS defining serious illnesses such as cardiovascular diseases. Thus, there is a relationship between persistent immune activation and coagulation/inflammation, although the mechanisms are poorly understood. Platelets play an important role in this process. Although interactions between platelets and elements of the innate immune system, such as monocytes, are well described, little is known about the interaction between platelets and the adaptive immune system. Design: We investigated the interaction of a component of the coagulation system, platelets, and the adaptive immune system T cells. Methods: Healthy controls and combination antiretroviral therapy (cART)-treated HIV-infected patients with viral loads of less than 40 copies/ml for more than 15 months were analysed for platelet–T-cell conjugate formation. Results: Platelets can form conjugates with T cells and were preferentially seen in CD4+ and CD8+ T-cell subsets with more differentiated phenotypes [memory, memory/effector and terminal effector memory (TEM)]. Compared with healthy controls, these conjugates in patients with HIV infection were more frequent, more often composed of activated platelets (CD42b+CD62P+), and were significantly associated with the D-dimer serum levels. Conclusion: These data support a model in which platelet–T-cell conjugates may play a critical role in the fast recruitment of antigen-experienced T cells to the place of injury. This mechanism can contribute in maintaining a state of coagulation/inflammation observed in these patients contributing to the pathology of the disease. PMID:26002800

  11. Infection of human monocyte-derived dendritic cells by ANDES Hantavirus enhances pro-inflammatory state, the secretion of active MMP-9 and indirectly enhances endothelial permeability

    PubMed Central

    2011-01-01

    Background Andes virus (ANDV), a rodent-borne Hantavirus, is the major etiological agent of Hantavirus cardiopulmonary syndrome (HCPS) in South America, which is mainly characterized by a vascular leakage with high rate of fatal outcomes for infected patients. Currently, neither specific therapy nor vaccines are available against this pathogen. ANDV infects both dendritic and epithelial cells, but in despite that the severity of the disease directly correlates with the viral RNA load, considerable evidence suggests that immune mechanisms rather than direct viral cytopathology are responsible for plasma leakage in HCPS. Here, we assessed the possible effect of soluble factors, induced in viral-activated DCs, on endothelial permeability. Activated immune cells, including DC, secrete gelatinolytic matrix metalloproteases (gMMP-2 and -9) that modulate the vascular permeability for their trafficking. Methods A clinical ANDES isolate was used to infect DC derived from primary PBMC. Maturation and pro-inflammatory phenotypes of ANDES-infected DC were assessed by studying the expression of receptors, cytokines and active gMMP-9, as well as some of their functional status. The ANDES-infected DC supernatants were assessed for their capacity to enhance a monolayer endothelial permeability using primary human vascular endothelial cells (HUVEC). Results Here, we show that in vitro primary DCs infected by a clinical isolate of ANDV shed virus RNA and proteins, suggesting a competent viral replication in these cells. Moreover, this infection induces an enhanced expression of soluble pro-inflammatory factors, including TNF-α and the active gMMP-9, as well as a decreased expression of anti-inflammatory cytokines, such as IL-10 and TGF-β. These viral activated cells are less sensitive to apoptosis. Moreover, supernatants from ANDV-infected DCs were able to indirectly enhance the permeability of a monolayer of primary HUVEC. Conclusions Primary human DCs, that are primarily

  12. A pathogenic long noncoding RNA redesigns the epigenetic landscape of the infected cells by subverting host Histone Deacetylase 6 activity.

    PubMed

    Castellano, Mayte; Pallas, Vicente; Gomez, Gustavo

    2016-09-01

    Viroids - ancient plant-pathogenic long noncoding RNAs - have developed a singular evolutionary strategy based on reprogramming specific phases of host-metabolism to ensure that their infection cycle can be completed in infected cells. However, the molecular aspects governing this transregulatory phenomenon remain elusive. Here, we use immunoprecipitation assays and bisulfite sequencing of rDNA to shown that, in infected cucumber and Nicotiana benthamina plants, Hop stunt viroid (HSVd) recruits and functionally subverts Histone Deacetylase 6 (HDA6) to promote host-epigenetic alterations that trigger the transcriptional alterations observed during viroid pathogenesis. This notion is supported by the demonstration that, during infection, the HSVd-HDA6 complex occurs in vivo and that endogenous HDA6 expression is increased in HSVd-infected cells. Moreover, transient overexpression of recombinant HDA6 reverts the hypomethylation status of rDNA observed in HSVd-infected plants and reduces viroid accumulation. We hypothesize that the host-transcriptional alterations induced as a consequence of viroid-mediated HDA6 recruitment favor spurious recognition of HSVd-RNA as an RNA Pol II template, thereby improving viroid replication. Our results constitute the first description of a physical and functional interaction between a pathogenic RNA and a component of the host RNA silencing mechanism, providing novel evidence of the potential of these pathogenic lncRNAs to physically redesign the host-cell environment and reprogram their regulatory mechanisms. PMID:27174164

  13. Gammaherpesvirus Infection of Human Neuronal Cells

    PubMed Central

    Jha, Hem Chandra; Mehta, Devan; Lu, Jie; El-Naccache, Darine; Shukla, Sanket K.; Kovacsics, Colleen; Kolson, Dennis

    2015-01-01

    ABSTRACT Gammaherpesviruses human herpesvirus 4 (HHV4) and HHV8 are two prominent members of the herpesvirus family associated with a number of human cancers. HHV4, also known as Epstein-Barr virus (EBV), a ubiquitous gammaherpesvirus prevalent in 90 to 95% of the human population, is clinically associated with various neurological diseases such as primary central nervous system lymphoma, multiple sclerosis, Alzheimer’s disease, cerebellar ataxia, and encephalitis. However, the possibility that EBV and Kaposi’s sarcoma-associated herpesvirus (KSHV) can directly infect neurons has been largely overlooked. This study has, for the first time, characterized EBV infection in neural cell backgrounds by using the Sh-Sy5y neuroblastoma cell line, teratocarcinoma Ntera2 neurons, and primary human fetal neurons. Furthermore, we also demonstrated KSHV infection of neural Sh-Sy5y cells. These neuronal cells were infected with green fluorescent protein-expressing recombinant EBV or KSHV. Microscopy, genetic analysis, immunofluorescence, and Western blot analyses for specific viral antigens supported and validated the infection of these cells by EBV and KSHV and showed that the infection was efficient and productive. Progeny virus produced from infected neuronal cells efficiently infected fresh neuronal cells, as well as peripheral blood mononuclear cells. Furthermore, acyclovir was effective at inhibiting the production of virus from neuronal cells similar to lymphoblastoid cell lines; this suggests active lytic replication in infected neurons in vitro. These studies represent a potentially new in vitro model of EBV- and KSHV-associated neuronal disease development and pathogenesis. PMID:26628726

  14. Failure of antigen-stimulated gammadelta T cells and CD4+ T cells from sensitized cattle to upregulate nitric oxide and mycobactericidal activity of autologous Mycobacterium avium subsp. paratuberculosis-infected macrophages.

    PubMed

    Simutis, Frank J; Jones, Douglas E; Hostetter, Jesse M

    2007-03-15

    The function of gammadelta T cells during ruminant paratuberculosis (Johne's disease) is presently unknown. An ex vivo system was used to test the hypothesis that gammadelta T cells are capable of activating Mycobacterium avium subsp. paratuberculosis-(M. paratuberculosis)-infected macrophages. Peripheral blood-derived macrophages were infected in vitro with live M. paratuberculosis, and autologous LN-derived gammadelta T cells or CD4+ T cells were co-cultured with infected macrophages for 48h, at which time bacterial survival as well as production of nitrites and IFN-gamma was evaluated. Incubation of M. paratuberculosis-infected macrophages with autologous gammadelta T cells did not result in reduced intracellular bacterial viability compared to infected macrophage cultures without added T cells. IFN-gamma production by-infected cultures containing added gammadelta T cells was not enhanced compared to that of infected macrophages alone. Although infection of macrophage cultures caused increased production of nitrites at both post-infection day (PID) 0 and PID 60, the addition of gammadelta T cells did not further increase nitrite production. In contrast, addition of PPD-stimulated CD4+ T cells obtained at PID 60 to M. paratuberculosis-infected macrophages resulted in significantly increased IFN-gamma production compared to cultures without added T cells or cultures containing unstimulated CD4+ T cells or unstimulated or antigen-stimulated gammadelta T cells. However, the increased production of IFN-gamma by co-cultures containing PPD-stimulated CD4+ T cells did not result in increased bacterial killing or increased production of nitrites compared to cultures without added T cells. In additional in vitro experiments, M. paratuberculosis-infected macrophages, but not uninfected macrophages, were unable to increase nitrite production when stimulated with recombinant IFN-gamma. Taken together, the data suggest that (1) gammadelta T cells do not produce significant

  15. Suppression of Foxo1 Activity and Down-Modulation of CD62L (L-Selectin) in HIV-1 Infected Resting CD4 T Cells

    PubMed Central

    Trinité, Benjamin; Chan, Chi N.; Lee, Caroline S.; Mahajan, Saurabh; Luo, Yang; Muesing, Mark A.; Folkvord, Joy M.; Pham, Michael; Connick, Elizabeth; Levy, David N.

    2014-01-01

    HIV-1 hijacks and disrupts many processes in the cells it infects in order to suppress antiviral immunity and to facilitate its replication. Resting CD4 T cells are important early targets of HIV-1 infection in which HIV-1 must overcome intrinsic barriers to viral replication. Although resting CD4 T cells are refractory to infection in vitro, local environmental factors within lymphoid and mucosal tissues such as cytokines facilitate viral replication while maintaining the resting state. These factors can be utilized in vitro to study HIV-1 replication in resting CD4 T cells. In vivo, the migration of resting naïve and central memory T cells into lymphoid tissues is dependent upon expression of CD62L (L-selectin), a receptor that is subsequently down-modulated following T cell activation. CD62L gene transcription is maintained in resting T cells by Foxo1 and KLF2, transcription factors that maintain T cell quiescence and which regulate additional cellular processes including survival, migration, and differentiation. Here we report that HIV-1 down-modulates CD62L in productively infected naïve and memory resting CD4 T cells while suppressing Foxo1 activity and the expression of KLF2 mRNA. Partial T cell activation was further evident as an increase in CD69 expression. Several other Foxo1- and KLF2-regulated mRNA were increased or decreased in productively infected CD4 T cells, including IL-7rα, Myc, CCR5, Fam65b, S1P1 (EDG1), CD52, Cyclin D2 and p21CIP1, indicating a profound reprogramming of these cells. The Foxo1 inhibitor AS1842856 accelerated de novo viral gene expression and the sequella of infection, supporting the notion that HIV-1 suppression of Foxo1 activity may be a strategy to promote replication in resting CD4 T cells. As Foxo1 is an investigative cancer therapy target, the development of Foxo1 interventions may assist the quest to specifically suppress or activate HIV-1 replication in vivo. PMID:25330112

  16. Indoleamine 2,3-dioxygenase (IDO) activity during the primary immune response to influenza infection modifies the memory T cell response to influenza challenge.

    PubMed

    Sage, Leo K; Fox, Julie M; Mellor, Andrew L; Tompkins, Stephen M; Tripp, Ralph A

    2014-04-01

    The generation of a heterosubtypic memory T cell response is important for cross-protective immunity against unrelated strains of influenza virus. One way to facilitate the generation of the memory T cell population is to control the activity of immune modulatory agents. The enzyme, indoleamine 2,3-dioxygenase (IDO), is upregulated during influenza infection by the interferon response where IDO activity depletes tryptophan required in T cell response. In this study, IDO activity was pharmacologically inhibited with 1-methyl-tryptophan (1MT) during the primary response to influenza virus infection and the effect on the memory T cell response was evaluated. 1MT treatment improved the memory T cell response to influenza virus challenge by increasing interferon gamma expression by CD4 and CD8 T cells, and numbers of lung virus-specific CD8+ T cells, and increased the Th1 response as well as modifying the immunodominance hierarchy to increase the number of subdominant epitope specific CD8+ T cells, a feature which may be linked to decreased regulatory T cell function. These changes also accompanied evidence of accelerated lung tissue repair upon virus challenge. These findings suggest that modulation of IDO activity could be exploited in influenza vaccine development to enhance memory T cell responses and reduce disease burden. PMID:24702331

  17. Deep transcriptional sequencing of mucosal challenge compartment from rhesus macaques acutely infected with simian immunodeficiency virus implicates loss of cell adhesion preceding immune activation.

    PubMed

    Barrenas, Fredrik; Palermo, Robert E; Agricola, Brian; Agy, Michael B; Aicher, Lauri; Carter, Victoria; Flanary, Leon; Green, Richard R; McLain, Randy; Li, Qingsheng; Lu, Wuxun; Murnane, Robert; Peng, Xinxia; Thomas, Matthew J; Weiss, Jeffrey M; Anderson, David M; Katze, Michael G

    2014-07-01

    Pathology resulting from human immunodeficiency virus (HIV) infection is driven by protracted inflammation; the primary loss of CD4(+) T cells is caused by activation-driven apoptosis. Recent studies of nonhuman primates (NHPs) have suggested that during the acute phase of infection, antiviral mucosal immunity restricts viral replication in the primary infection compartment. These studies imply that HIV achieves systemic infection as a consequence of a failure in host antiviral immunity. Here, we used high-dose intrarectal inoculation of rhesus macaques with simian immunodeficiency virus (SIV) SIVmac251 to examine how the mucosal immune system is overcome by SIV during acute infection. The host response in rectal mucosa was characterized by deep mRNA sequencing (mRNA-seq) at 3 and 12 days postinoculation (dpi) in 4 animals for each time point. While we observed a strong host transcriptional response at 3 dpi, functions relating to antiviral immunity were absent. Instead, we observed a significant number of differentially expressed genes relating to cell adhesion and reorganization of the cytoskeleton. We also observed downregulation of genes encoding members of the claudin family of cell adhesion molecules, which are coexpressed with genes associated with pathology in the colorectal mucosa, and a large number of noncoding transcripts. In contrast, at 12 dpi the differentially expressed genes were enriched in those involved with immune system functions, in particular, functions relating to T cells, B cells, and NK cells. Our findings indicate that host responses that negatively affect mucosal integrity occur before inflammation. Consequently, when inflammation is activated at peak viremia, mucosal integrity is already compromised, potentially enabling rapid tissue damage, driving further inflammation. Importance: The HIV pandemic is one of the major threats to human health, causing over a million deaths per year. Recent studies have suggested that mucosal antiviral

  18. Activation of H2AX and ATM in varicella-zoster virus (VZV)-infected cells is associated with expression of specific VZV genes.

    PubMed

    Yamamoto, Takenobu; Ali, Mir A; Liu, XueQiao; Cohen, Jeffrey I

    2014-03-01

    Mammalian cells activate DNA damage response pathways in response to virus infections. Activation of these pathways can enhance replication of many viruses, including herpesviruses. Activation of cellular ATM results in phosphorylation of H2AX and recruits proteins to sites of DNA damage. We found that varicella-zoster (VZV) infected cells had elevated levels of phosphorylated H2AX and phosphorylated ATM and that these levels increased in cells infected with VZV deleted for ORF61 or ORF63, but not deleted for ORF67. Expression of VZV ORF61, ORF62, or ORF63 alone did not result in phosphorylation of H2AX. While BGLF4, the Epstein-Barr virus homolog of VZV ORF47 protein kinase, phosphorylates H2AX and ATM, neither VZV ORF47 nor ORF66 protein kinase phosphorylated H2AX or ATM. Cells lacking ATM had no reduction in VZV replication. Thus, VZV induces phosphorylation of H2AX and ATM and this effect is associated with the presence of specific VZV genes in virus-infected cells.

  19. Abortive infection of snakehead fish vesiculovirus in ZF4 cells was associated with the RLRs pathway activation by viral replicative intermediates.

    PubMed

    Wang, Wenwen; Asim, Muhammad; Yi, Lizhu; Hegazy, Abeer M; Hu, Xianqin; Zhou, Yang; Ai, Taoshan; Lin, Li

    2015-03-18

    Snakehead fish vesiculovirus (SHVV) is a negative strand RNA virus which can cause great economic losses in fish culture. To facilitate the study of SHVV-host interactions, the susceptibility of zebrafish embryonic fibroblast cell line (ZF4) to the SHVV was investigated in this report. The results showed that high amount of viral mRNAs and cRNAs were detected at the 3 h post-infection. However, the expressions of the viral mRNAs and cRNA were decreased dramatically after 6 h post-infection. In addition, the expressions of interferon (IFN) and interferon-induced GTP-binding protein Mx were all up regulated significantly at the late stage of the infection. Meanwhile, the expressions of Retinoic acid-inducible gene I (RIG-I) and Melanoma differentiation-associated gene 5 (MDA5) were also all up-regulated significantly during the infection. Two isoforms of DrLGP2 from zebrafish were also cloned and analyzed. Interestingly, the expression of DrLGP2a but not DrLGP2b was significantly up-regulated at both mRNA and protein levels, indicating that the two DrLGP2 isoforms might play different roles during the SHVV infection. Transfection experiment showed that viral replicative intermediates were required for the activation of IFN-α expression. Taken together, the abortive infection of SHVV in ZF4 cells was associated with the activation of RLRs pathway, which was activated by viral replicative intermediates.

  20. Regulation of de novo translation of host cells by manipulation of PERK/PKR and GADD34-PP1 activity during Newcastle disease virus infection.

    PubMed

    Liao, Ying; Gu, Feng; Mao, Xiang; Niu, Qiaona; Wang, Huaxia; Sun, Yingjie; Song, Cuiping; Qiu, Xusheng; Tan, Lei; Ding, Chan

    2016-04-01

    Viral infections result in cellular stress responses, which can trigger protein translation shutoff via phosphorylation of eukaryotic initiation factor 2 alpha (eIF2α). Newcastle disease virus (NDV) causes severe disease in poultry and selectively kills human tumour cells. In this report, we determined that infection of HeLa human cervical cancer cells and DF-1 chicken fibroblast cells with NDV maintained protein at early infection times, 0-12 h post-infection (p.i.), and gradually inhibited global protein translation at late infection times, 12-24 h p.i. Mechanistic studies showed that translation inhibition at late infection times was accompanied by phosphorylation of eIF2α, a checkpoint of translation initiation. Meanwhile, the eIF2α kinase, PKR, was upregulated and activated by phosphorylation and another eIF2α kinase, PERK, was phosphorylated and cleaved into two fragments. Pharmacological inhibition experiments revealed that only PKR activity was required for eIF2α phosphorylation, suggesting that recognition of viral dsRNA by PKR was responsible for translation shutoff. High levels of phospho-eIF2α led to preferential translation of the transcription factor ATF4 and an increase in GADD34 expression. Functionally, GADD34, in conjunction with PP1, dephosphorylated eIF2a and restored protein translation, benefiting virus protein synthesis. However, PP1 was degraded at late infection times, functionally counteracting the upregulation of GADD34. Taken together, our data support that NDV-induced translation shutoff at late infection times was attributed to sustaining phosphorylation of eIF2α, which is mediated by continual activation of PKR and degradation of PP1.

  1. In vitro activation of peripheral mononuclear cells by zinc in HIV-infected patients and healthy controls.

    PubMed Central

    Harrer, T; Wolf, B; Näger, W; Schwarz, W; Bergner, D; Kalden, J R

    1992-01-01

    Zinc is a mitogen for peripheral blood mononuclear cells (PBMC). The optimal mitogenic concentration was found to be 0.05 mmol/l (327 micrograms/dl), four times higher than physiological serum levels. Maximal proliferation was observed after 6 days. Limited dilution technique revealed a frequency of zinc reactive cells of 1:3467 (median; range 1:1628-1:6235). Cord blood mononuclear cells from four of six healthy children could be stimulated to proliferate by zinc. A normal zinc-induced proliferative response could be demonstrated in all six HIV-infected patients in the Walter-Reed-stage I, in nine of 11 patients in Walter-Reed II and in only two of five patients in Walter-Reed III. In Walter-Reed IV to VI all eight patients showed a weak response to zinc (less than 50% of the healthy day control). Decreased zinc serum levels were found in 10 of 28 patients and in one of 16 controls. There was a significant correlation of a diminished zinc-induced proliferation with lower serum levels of zinc and a reduced proportion of CD4 helper cells in HIV-1-infected men. Because of a suppression of mitogenesis by high dose of zinc an excessive intake of zinc as used by some HIV-1-infected patients can presently not be recommended. The value of zinc-induced proliferation for monitoring HIV-infected patients has still to be established. PMID:1638772

  2. A species-specific activation of Toll-like receptor signaling in bovine and sheep bronchial epithelial cells triggered by Mycobacterial infections.

    PubMed

    Ma, Yan; Han, Fei; Liang, Jinping; Yang, Jiali; Shi, Juan; Xue, Jing; Yang, Li; Li, Yong; Luo, Meihui; Wang, Yujiong; Wei, Jun; Liu, Xiaoming

    2016-03-01

    Pulmonary tuberculosis caused by a Mycobacterium infection remains a major public health problem in most part of the world, in part owing to the transmission of its pathogens between hosts including human, domestic and wild animals. To date, molecular mechanisms of the pathogenesis of TB are still incompletely understood. In addition to alveolar macrophages, airway epithelial cells have also been recently recognized as main targets for Mycobacteria infections. In an effort to understand the pathogen-host interaction between Mycobacteria and airway epithelial cells in domestic animals, in present study, we investigated the Toll-like receptor (TLR) signaling in bovine and sheep airway epithelial cells in response to an infection of Mycobacterium tuberculosis avirulent H37Ra stain or Mycobacterium bovis BCG vaccine strain, using primary air-liquid interface (ALI) bronchial epithelial culture models. Our results revealed a host and pathogen species-specific TLR-mediated recognition of pathogen-associated molecular patterns (PAMPs), induction and activation of TLR signaling pathways, and substantial induction of inflammatory response in bronchial epithelial cells in response to Mycobacteria infections between these two species. Interestingly, the activation TLR signaling in bovine bronchial epithelial cells induced by Mycobacteria infection was mainly through a myeloid differentiation factor 88 (MyD88)-independent TLR signaling pathway, while both MyD88-dependent and independent TLR signaling cascades could be induced in sheep epithelial cells. Equally noteworthy, a BCG infection was able to induce both MyD88-dependent and independent signaling in sheep and bovine airway epithelial cells, but more robust inflammatory responses were induced in sheep epithelial cells relative to the bovines; whereas an H37Ra infection displayed an ability to mainly trigger a MyD88-independent TLR signaling cascade in these two host species, and induce a more extent expression of

  3. Natural Killer cell activation distinguishes M. tuberculosis-mediated Immune reconstitution syndrome (IRIS) from chronic HIV and HIV-MTB co-infection

    PubMed Central

    Conradie, F.; Foulkes, A.S.; Ive, P.; Yin, X.; Roussos, K.; Glencross, D.K.; Lawrie, D.; Stevens, W.; Montaner, L.J.; Sanne; Azzoni, L.

    2011-01-01

    Background With increased access to antiretroviral treatment (ART), Immune Reconstitution Inflammatory Syndrome (IRIS) in Mycobacterium tuberculosis (MTB)-infected populations remains a clinical challenge. We studied a cross-sectional cohort of HIV-infected subjects in Johannesburg (South Africa) to help define the immune correlates that best distinguish IRIS from ongoing MTB cases. Methods We studied HIV+ subjects developing MTB-related unmasking IRIS (u-TB-IRIS) after ART initiation; control groups were HIV subjects and HIV-TB co-infected subjects with comparable ART treatment. Testing was conducted with whole blood-based 4-color flow cytometry and plasma-based Luminex cytokine assessment. Results NK cell activation, C-reactive protein and IL-8 serum concentration were significantly higher in u-TB-IRIS subjects as compared to both control groups. In addition, all MTB co-infected subjects, independent of clinical presentation, had higher neutrophils and T cell activation, together with lower lymphocytes, CD4+ T cell and myeloid DC counts. Using conditional inference tree analysis we show that elevated NK cell activation in combination with lymphocyte count characterizes the immunological profile of u-TB-IRIS. Conclusions Our results support a role for innate immune effectors in the immunopathogenesis of unmasking MTB-related IRIS, and identify new immune parameters defining this pathology. PMID:21826013

  4. Disruption of Early Tumor Necrosis Factor Alpha Signaling Prevents Classical Activation of Dendritic Cells in Lung-Associated Lymph Nodes and Development of Protective Immunity against Cryptococcal Infection

    PubMed Central

    Xu, Jintao; Eastman, Alison J.; Flaczyk, Adam; Neal, Lori M.; Zhao, Guolei; Carolan, Jacob; Malachowski, Antoni N.; Stolberg, Valerie R.; Yosri, Mohammed; Chensue, Stephen W.; Curtis, Jeffrey L.; Osterholzer, John J.

    2016-01-01

    ABSTRACT Anti-tumor necrosis factor alpha (anti-TNF-α) therapies have been increasingly used to treat inflammatory diseases and are associated with increased risk of invasive fungal infections, including Cryptococcus neoformans infection. Using a mouse model of cryptococcal infection, we investigated the mechanism by which disruption of early TNF-α signaling results in the development of nonprotective immunity against C. neoformans. We found that transient depletion of TNF-α inhibited pulmonary fungal clearance and enhanced extrapulmonary dissemination of C. neoformans during the adaptive phase of the immune response. Higher fungal burdens in TNF-α-depleted mice were accompanied by markedly impaired Th1 and Th17 responses in the infected lungs. Furthermore, early TNF-α depletion also resulted in disrupted transcriptional initiation of the Th17 polarization program and subsequent upregulation of Th1 genes in CD4+ T cells in the lung-associated lymph nodes (LALN) of C. neoformans-infected mice. These defects in LALN T cell responses were preceded by a dramatic shift from a classical toward an alternative activation of dendritic cells (DC) in the LALN of TNF-α-depleted mice. Taken together, our results indicate that early TNF-α signaling is required for optimal DC activation, and the initial Th17 response followed by Th1 transcriptional prepolarization of T cells in the LALN, which further drives the development of protective immunity against cryptococcal infection in the lungs. Thus, administration of anti-TNF-α may introduce a particularly greater risk for newly acquired fungal infections that require generation of protective Th1/Th17 responses for their containment and clearance. PMID:27406560

  5. [Identification of Env-specific monoclonal antibodies from Chinese HIV-1 infected person by B cell activation and RT-PCR cloning].

    PubMed

    Wang, Hui-Min; Xu, Ke; Yu, Shuang-Qing; Ding, Lin-Lin; Luo, Hai-Yan; Flinko, Robin; Lewis, George K; Feng, Xia; Shao, Ji-Rong; Guan, Yong-Jun; Zeng, Yi

    2012-06-01

    To obtain protective human monoclonal antibody from HIV-1 infected person, we adapted a technology for isolating antigen specific monoclonal antibody from human memory B cells through in vitro B cell activation coupled with RT-PCT and expression cloning. Human B cells were purified by negative sorting from PBMCs of HIV-1 infected individuals and memory B cells were further enriched using anti-CD27 microbeads. Two hundred memory B cells per well were cultured in 96-well round-bottom plates Env-specific antibodies in supernatants were with feeder cells in medium containing EBV and CpG. screened by ELISA after 1-2 weeks' culture. Cells from positive wells of Env-specific antibody were harvested and total RNA was isolated. Human VH and Vkappa or Vlambda genes were amplified by RT-PCR and cloned into IgG1 and kappa or lambda expressing vectors. Functional VH and Vkappa or Vlambda were identified by cotransfecting 293T cells with individual heavy chain and light chain clones followed by analysis of culture supernatants by ELISA for Env-specific antibodies. Finally, corresponding mAb was produced by transient transfection of 293T cells with the identified VH and Vkappa/lambda pair and purified by protein A affinity chromatography. Purified monocolonal antibodies were used for HIV-1 specific antibody-dependent cell-mediated cytotoxicity (ADCC) and neutralizing activity assay. Four monocolonal Env-specific antibodies were isolated from one HIV-1 subtype B' infected individual. Two of them showed strong ADCC activity and one showed weak neutralizing activity against HIV-1. Its further studies on their application in therapeutic or prophylactic vaccines against HIV-1 should be grounded. PMID:22978159

  6. Glial Cell-Elicited Activation of Brain Microvasculature in Response to Brucella abortus Infection Requires ASC Inflammasome-Dependent IL-1β Production.

    PubMed

    Miraglia, M Cruz; Costa Franco, Miriam M; Rodriguez, Ana M; Bellozi, Paula M Q; Ferrari, Carina C; Farias, Maria I; Dennis, Vida A; Barrionuevo, Paula; de Oliveira, Antonio C P; Pitossi, Fernando; Kim, Kwang Sik; Delpino, M Victoria; Oliveira, Sergio Costa; Giambartolomei, Guillermo H

    2016-05-01

    Blood-brain barrier activation and/or dysfunction are a common feature of human neurobrucellosis, but the underlying pathogenic mechanisms are largely unknown. In this article, we describe an immune mechanism for inflammatory activation of human brain microvascular endothelial cells (HBMEC) in response to infection with Brucella abortus Infection of HBMEC with B. abortus induced the secretion of IL-6, IL-8, and MCP-1, and the upregulation of CD54 (ICAM-1), consistent with a state of activation. Culture supernatants (CS) from glial cells (astrocytes and microglia) infected with B. abortus also induced activation of HBMEC, but to a greater extent. Although B. abortus-infected glial cells secreted IL-1β and TNF-α, activation of HBMEC was dependent on IL-1β because CS from B. abortus-infected astrocytes and microglia deficient in caspase-1 and apoptosis-associated speck-like protein containing a CARD failed to induce HBMEC activation. Consistently, treatment of CS with neutralizing anti-IL-1β inhibited HBMEC activation. Both absent in melanoma 2 and Nod-like receptor containing a pyrin domain 3 are partially required for caspase-1 activation and IL-1β secretion, suggesting that multiple apoptosis-associated speck-like protein containing CARD-dependent inflammasomes contribute to IL-1β-induced activation of the brain microvasculature. Inflammasome-mediated IL-1β secretion in glial cells depends on TLR2 and MyD88 adapter-like/TIRAP. Finally, neutrophil and monocyte migration across HBMEC monolayers was increased by CS from Brucella-infected glial cells in an IL-1β-dependent fashion, and the infiltration of neutrophils into the brain parenchyma upon intracranial injection of B. abortus was diminished in the absence of Nod-like receptor containing a pyrin domain 3 and absent in melanoma 2. Our results indicate that innate immunity of the CNS set in motion by B. abortus contributes to the activation of the blood-brain barrier in neurobrucellosis and IL-1β mediates

  7. Endothelial Cell Proteomic Response to Rickettsia conorii Infection Reveals Activation of the Janus Kinase (JAK)-Signal Transducer and Activator of Transcription (STAT)-Inferferon Stimulated Gene (ISG)15 Pathway and Reprogramming Plasma Membrane Integrin/Cadherin Signaling.

    PubMed

    Zhao, Yingxin; Valbuena, Gustavo; Walker, David H; Gazi, Michal; Hidalgo, Marylin; DeSousa, Rita; Oteo, Jose Antonio; Goez, Yenny; Brasier, Allan R

    2016-01-01

    Rickettsia conorii is the etiologic agent of Mediterranean spotted fever, a re-emerging infectious disease with significant mortality. This Gram-negative, obligately intracellular pathogen is transmitted via tick bites, resulting in disseminated vascular endothelial cell infection with vascular leakage. In the infected human, Rickettsia conorii infects endothelial cells, stimulating expression of cytokines and pro-coagulant factors. However, the integrated proteomic response of human endothelial cells to R. conorii infection is not known. In this study, we performed quantitative proteomic profiling of primary human umbilical vein endothelial cells (HUVECs) with established R conorii infection versus those stimulated with endotoxin (LPS) alone. We observed differential expression of 55 proteins in HUVEC whole cell lysates. Of these, we observed induction of signal transducer and activator of transcription (STAT)1, MX dynamin-like GTPase (MX1), and ISG15 ubiquitin-like modifier, indicating activation of the JAK-STAT signaling pathway occurs in R. conorii-infected HUVECs. The down-regulated proteins included those involved in the pyrimidine and arginine biosynthetic pathways. A highly specific biotinylated cross-linking enrichment protocol was performed to identify dysregulation of 11 integral plasma membrane proteins that included up-regulated expression of a sodium/potassium transporter and down-regulation of α-actin 1. Analysis of Golgi and soluble Golgi fractions identified up-regulated proteins involved in platelet-endothelial adhesion, phospholipase activity, and IFN activity. Thirty four rickettsial proteins were identified with high confidence in the Golgi, plasma membrane, or secreted protein fractions. The host proteins associated with rickettsial infections indicate activation of interferon-STAT signaling pathways; the disruption of cellular adhesion and alteration of antigen presentation pathways in response to rickettsial infections are distinct from

  8. P47phox−/− Mice Are Compromised in Expansion and Activation of CD8+ T Cells and Susceptible to Trypanosoma cruzi Infection

    PubMed Central

    Dhiman, Monisha; Garg, Nisha Jain

    2014-01-01

    Macrophage activation of NAD(P)H oxidase (NOX2) and reactive oxygen species (ROS) is suggested to kill Trypanosoma cruzi that causes Chagas disease. However, the role of NOX2 in generation of protective immunity and whether these mechanisms are deregulated in the event of NOX2 deficiency are not known, and examined in this study. Our data showed that C57BL/6 p47phox−/− mice (lack NOX2 activity), as compared to wild-type (WT) mice, succumbed within 30 days post-infection (pi) to low doses of T. cruzi and exhibited inability to control tissue parasites. P47phox−/− bone-marrow and splenic monocytes were not compromised in maturation, phagocytosis and parasite uptake capacity. The deficiency of NOX2 mediated ROS was compensated by higher level of inducible nitric oxide synthase (iNOS) expression, and nitric oxide and inflammatory cytokine (TNF-α, IFN-γ, IL-1β) release by p47phox−/− macrophages as compared to that noted in WT controls infected by T. cruzi. Splenic activation of Th1 CD4+T cells and tissue infiltration of immune cells in T. cruzi infected p47phox−/− mice were comparable to that noted in infected control mice. However, generation and activation of type 1 CD8+T cells was severely compromised in p47phox−/− mice. In comparison, WT mice exhibited a robust T. cruzi-specific CD8+T cell response with type 1 (IFN-γ+TNF-α>IL-4+IL-10), cytolytic effector (CD8+CD107a+IFN-γ+) phenotype. We conclude that NOX2/ROS activity in macrophages signals the development of antigen-specific CD8+T cell response. In the event of NOX2 deficiency, a compromised CD8+T cell response is generated, leading to increased parasite burden, tissue pathogenesis and mortality in chagasic mice. PMID:25474113

  9. Comparative Analysis of Immune Activation Markers of CD8+ T Cells in Lymph Nodes of Different Origins in SIV-Infected Chinese Rhesus Macaques

    PubMed Central

    Liu, Jinbiao; Xiao, Qianhao; Zhou, Runhong; Wang, Yong; Xian, Qiaoyang; Ma, Tongcui; Zhuang, Ke; Zhou, Li; Guo, Deyin; Wang, Xu; Ho, Wen-Zhe; Li, Jieliang

    2016-01-01

    Altered T-cell homeostasis, such as expansion of CD8+ T cells to the secondary lymphatic compartments, has been suggested as a mechanism of HIV/simian immunodeficiency virus (SIV)-pathogenesis. However, the role of immune activation of CD8+ T cells in the CD4/CD8 turnover and viral replication in these tissues is not completely understood. In this study, we compared the expression of immune activation markers (CD69 and HLA-DR) on CD8+ T cells in the peripheral blood and lymph nodes (LNs) of SIV-infected/uninfected Chinese rhesus macaques. SIV-infected macaques had significantly higher percentages of CD8+CD69+ and CD8+HLA-DR+ T cells in all these anatomical compartments than uninfected macaques. LNs that located close to the gastrointestinal (GI) tract (colon, mesenteric, and iliac LNs) of SIV-infected macaques had profoundly lower numbers of CD4+ T cells, but no significant difference in expression of activation marker (CD8+CD69+ and CD8+HLA-DR+) as compared with the peripheral lymphatic tissues (axillary and inguinal LNs). The CD4/CD8 ratios were negatively correlated with the activation of CD8+ T cells in the overall LNs, with further associations with CD8+HLA-DR+ in GI LNs while CD8+CD69+ in peripheral LNs. These observations demonstrate that the increase of CD8+ T cell activation is a contributing factor for the decline of CD4/CD8 ratios in GI system. PMID:27708644

  10. Low Thymic Activity and Dendritic Cell Numbers Are Associated with the Immune Response to Primary Viral Infection in Elderly Humans.

    PubMed

    Schulz, Axel Ronald; Mälzer, Julia Nora; Domingo, Cristina; Jürchott, Karsten; Grützkau, Andreas; Babel, Nina; Nienen, Mikalai; Jelinek, Tomas; Niedrig, Matthias; Thiel, Andreas

    2015-11-15

    Immunological competence declines progressively with age, resulting in increased susceptibility of the elderly to infection and impaired responses to vaccines. Underlying mechanisms remain largely obscure as they have been related to complex, individual systemic immune properties that are challenging to investigate. In this study, we explored age-related changes in human immunity during a primary virus infection experimentally induced by immunization with live-attenuated yellow fever (YF) vaccine. Applying detailed serology, advanced FACS analysis, and systems biology, we discovered that aged subjects developed fewer neutralizing Abs, mounted diminished YF-specific CD8(+) T cell responses, and showed quantitatively and qualitatively altered YF-specific CD4(+) T cell immunity. Among numerous immune signatures, low in vivo numbers of naive CD4(+) recent thymic emigrants and peripheral dendritic cells correlated well with reduced acute responsiveness and altered long-term persistence of human cellular immunity to YF vaccination. Hence, we reveal in this article that essential elements of immune responses such as recent thymic emigrants and dendritic cells strongly relate to productive immunity in the elderly, providing a conceivable explanation for diminished responsiveness to vaccination with neoantigens and infection with de novo pathogens in the aged population. PMID:26459351

  11. Microarray analysis of Etrog citron (Citrus medica L.) reveals changes in chloroplast, cell wall, peroxidase and symporter activities in response to viroid infection.

    PubMed

    Rizza, Serena; Conesa, Ana; Juarez, José; Catara, Antonino; Navarro, Luis; Duran-Vila, Nuria; Ancillo, Gema

    2012-10-01

    Viroids are small (246-401 nucleotides), single-stranded, circular RNA molecules that infect several crop plants and can cause diseases of economic importance. Citrus are the hosts in which the largest number of viroids have been identified. Citrus exocortis viroid (CEVd), the causal agent of citrus exocortis disease, induces considerable losses in citrus crops. Changes in the gene expression profile during the early (pre-symptomatic) and late (post-symptomatic) stages of Etrog citron infected with CEVd were investigated using a citrus cDNA microarray. MaSigPro analysis was performed and, on the basis of gene expression profiles as a function of the time after infection, the differentially expressed genes were classified into five clusters. FatiScan analysis revealed significant enrichment of functional categories for each cluster, indicating that viroid infection triggers important changes in chloroplast, cell wall, peroxidase and symporter activities.

  12. Effects of Developmental Activation of the AhR on CD4+ T-Cell Responses to Influenza Virus Infection in Adult Mice

    PubMed Central

    Boule, Lisbeth A.; Winans, Bethany

    2014-01-01

    Background: Epidemiological and animal studies indicate that maternal exposure to pollutants that bind the aryl hydrocarbon receptor (AhR) correlates with poorer ability to combat respiratory infection and lower antibody levels in the offspring. These observations point to an impact on CD4+ T cells. Yet, the consequence of developmental exposure to AhR ligands on the activation and differentiation of CD4+ T cells has not been directly examined. Objectives: Our goal was to determine whether maternal exposure to an AhR ligand directly alters CD4+ T cell differentiation and function later in life. Methods: C57BL/6 mice were exposed to a prototypical AhR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), in utero and via suckling. We then measured CD4+ T-cell activation and differentiation into distinct effector populations in adult offspring that were infected with influenza A virus (IAV). Reciprocal adoptive transfers were used to define whether modifications in CD4+ T-cell responses resulted from direct effects of developmental TCDD exposure on CD4+ T cells. Results: Developmental exposure skewed CD4+ T-cell responses to IAV infection. We observed fewer virus-specific, activated CD4+ T cells and a reduced frequency of conventional CD4+ effector-cell subsets. However, there was an increase in regulatory CD4+ T cells. Direct effects of AhR activation on CD4+ T cells resulted in impaired differentiation into conventional effector subsets; this defect was transferred to mice that had not been developmentally exposed to TCDD. Conclusions: Maternal exposure to TCDD resulted in durable changes in the responsive capacity and differentiation of CD4+ T cells in adult C57BL/6 mice. Citation: Boule LA, Winans B, Lawrence BP. 2014. Effects of developmental activation of the AhR on CD4+ T-cell responses to influenza virus infection in adult mice. Environ Health Perspect 122:1201–1208; http://dx.doi.org/10.1289/ehp.1408110 PMID:25051576

  13. Nodavirus infection induces a great innate cell-mediated cytotoxic activity in resistant, gilthead seabream, and susceptible, European sea bass, teleost fish.

    PubMed

    Chaves-Pozo, Elena; Guardiola, Francisco A; Meseguer, José; Esteban, María A; Cuesta, Alberto

    2012-11-01

    Viral nervous necrosis (VNN) virus produces great mortalities in fish having susceptible and reservoir species between the most important marine aquaculture species. Cell-mediated cytotoxicity (CMC) is considered, towards the interferon (IFN), the most important mechanism of the immune response to fight against viral infections but it has been very scarcely evaluated. We aimed to evaluate the effects of VNNV infection in the reservoir gilthead seabream (Sparus aurata) and susceptible European sea bass (Dicentrarchus labrax). Firstly, after experimental infection we found mortalities in the sea bass (55%) but no in the seabream. Moreover, VNN virus replicates in the brain of both species as it was reflected by the high up-regulation of the Mx gene expression. Interestingly, the head-kidney leucocyte cell-mediated cytotoxic activity was significantly increased in both species reaching highest activity at 7 days: 3.65- and 2.7-fold increase in seabream and sea bass, respectively. This is supported by the significant up-regulation of the non-specific cytotoxic cell receptor (NCCRP-1) in the two fish species. By contrast, phagocytosis was unaffected in both species. The respiratory burst was increased in seabream 7 days post-infection whilst in sea bass this activity was significantly decreased at days 7 and 15. Our results demonstrate the significance of the CMC activity in both gilthead seabream and European sea bass against nodavirus infections but further studies are still needed to understand the role of cytotoxic cells in the antiviral immune response and the mechanisms involved in either reservoir or susceptible fish species. PMID:22981914

  14. Biphasic activation of PI3K/Akt and MAPK/Erk1/2 signaling pathways in bovine herpesvirus type 1 infection of MDBK cells.

    PubMed

    Zhu, Liqian; Ding, Xiuyan; Zhu, Xiaofang; Meng, Songshu; Wang, Jianye; Zhou, Hong; Duan, Qiangde; Tao, Jie; Schifferli, Dieter M; Zhu, Guoqiang

    2011-04-14

    Many viruses have been known to control key cellular signaling pathways to facilitate the virus infection. The possible involvement of signaling pathways in bovine herpesvirus type 1 (BoHV-1) infection is unknown. This study indicated that infection of MDBK cells with BoHV-1 induced an early-stage transient and a late-stage sustained activation of both phosphatidylinositol 3-kinase (PI3K)/Akt and mitogen activated protein kinases/extracellular signal-regulated kinase 1/2 (MAPK/Erk1/2) signaling pathways. Analysis with the stimulation of UV-irradiated virus indicated that the virus binding and/or entry process was enough to trigger the early phase activations, while the late phase activations were viral protein expression dependent. Biphasic activation of both pathways was suppressed by the selective inhibitor, Ly294002 for PI3K and U0126 for MAPK kinase (MEK1/2), respectively. Furthermore, treatment of MDBK cells with Ly294002 caused a 1.5-log reduction in virus titer, while U0126 had little effect on the virus production. In addition, the inhibition effect of Ly294002 mainly occurred at the post-entry stage of the virus replication cycle. This revealed for the first time that BoHV-1 actively induced both PI3K/Akt and MAPK/Erk1/2 signaling pathways, and the activation of PI3K was important for fully efficient replication, especially for the post-entry stage.

  15. Increase in frequencies of circulating Th-17 cells correlates with microbial translocation, immune activation and exhaustion in HIV-1 infected patients with poor CD4 T-cell reconstitution.

    PubMed

    Valiathan, Ranjini; Asthana, Deshratn

    2016-05-01

    We analyzed the association of circulating Th-17 cells (cTh-17) with immune activation (IA), immune exhaustion (IE) and regulatory T-cells (T-regs) in 20 human immunodeficiency virus-1 (HIV-1) infected patients with impaired restoration of CD4 T-cell counts despite prolonged suppression of plasma viremia (discordant) and compared it with 20 HIV-1 infected patients showing good immunologic and virologic responses (concordant) following highly active antiretroviral therapy (HAART). Discordant HIV-1 infected patients showed significantly higher frequencies of cTh-17 cells compared to concordant patients and healthy controls after PMA+Ionomicin stimulation. Discordant patients also showed higher CD4 T-cell immune activation (HLA-DR+CD38+) than concordant patients which directly correlated with microbial translocation. Additionally, CD4 T-cells of discordant patients showed higher frequencies of CD4 T-cells expressing multiple immune exhaustion markers (Tim3+PD-1+) which correlated with immune activation indicating that combined analysis of inhibitory molecules along with PD-1 might be a better predictor for immune exhaustion of CD4 T-cells. Increased cTh-17 cell frequency correlated inversely with CD4 T-cell percentages and absolute counts and directly with CD4 T-cell immune activation and T-reg frequencies. Persistent CD4 T-cell immune activation might favor differentiation of activated CD4 T-cells toward cTh-17 phenotype in discordant patients. Discordant patients had significantly lower baseline CD4 T-cell counts and higher viral load at the initiation of HAART and higher immune activation and immune exhaustion after being on HAART for long time indicating that these factors might be associated with an increase in cTh-17 cell frequency, thus, increasing the risk of disease progression despite virologic control.

  16. CD81 controls immunity to Listeria infection through rac-dependent inhibition of proinflammatory mediator release and activation of cytotoxic T cells.

    PubMed

    Martínez del Hoyo, Gloria; Ramírez-Huesca, Marta; Levy, Shoshana; Boucheix, Claude; Rubinstein, Eric; Minguito de la Escalera, María; González-Cintado, Leticia; Ardavín, Carlos; Veiga, Esteban; Yáñez-Mó, María; Sánchez-Madrid, Francisco

    2015-06-15

    Despite recent evidence on the involvement of CD81 in pathogen binding and Ag presentation by dendritic cells (DCs), the molecular mechanism of how CD81 regulates immunity during infection remains to be elucidated. To investigate the role of CD81 in the regulation of defense mechanisms against microbial infections, we have used the Listeria monocytogenes infection model to explore the impact of CD81 deficiency in the innate and adaptive immune response against this pathogenic bacteria. We show that CD81(-/-) mice are less susceptible than wild-type mice to systemic Listeria infection, which correlates with increased numbers of inflammatory monocytes and DCs in CD81(-/-) spleens, the main subsets controlling early bacterial burden. Additionally, our data reveal that CD81 inhibits Rac/STAT-1 activation, leading to a negative regulation of the production of TNF-α and NO by inflammatory DCs and the activation of cytotoxic T cells by splenic CD8α(+) DCs. In conclusion, this study demonstrates that CD81-Rac interaction exerts an important regulatory role on the innate and adaptive immunity against bacterial infection and suggests a role for CD81 in the development of novel therapeutic targets during infectious diseases.

  17. The Immunomodulator VacA Promotes Immune Tolerance and Persistent Helicobacter pylori Infection through Its Activities on T-Cells and Antigen-Presenting Cells

    PubMed Central

    Djekic, Aleksandra; Müller, Anne

    2016-01-01

    VacA is a pore-forming toxin that has long been known to induce vacuolization in gastric epithelial cells and to be linked to gastric disorders caused by H. pylori infection. Its role as a major colonization and persistence determinant of H. pylori is less well-understood. The purpose of this review is to discuss the various target cell types of VacA and its mechanism of action; specifically, we focus on the evidence showing that VacA targets myeloid cells and T-cells to directly and indirectly prevent H. pylori-specific T-cell responses and immune control of the infection. In particular, the ability of VacA-proficient H. pylori to skew T-cell responses towards regulatory T-cells and the effects of Tregs on H. pylori chronicity are highlighted. The by-stander effects of VacA-driven immunomodulation on extragastric diseases are discussed as well. PMID:27322319

  18. Bcl-3 suppresses Tax-induced NF-κB activation through p65 nuclear translocation blockage in HTLV-1-infected cells.

    PubMed

    Wang, Jinheng; Li, Junying; Huang, Yanmei; Song, Xiangfeng; Niu, Zhiguo; Gao, Zhitao; Wang, Hui

    2013-01-01

    Human T cell leukemia virus type 1 (HTLV-1) Tax-induced persistent activation of the NF-κB pathway is perceived as the primary cause of adult T cell leukemia (ATL), an aggressive leukemia caused by HTLV-1. Although elevated oncoprotein Bcl-3 levels are found in many HTLV-1-infectedcell lines and ATL cells, the role of Bcl-3 in the malignant progression caused by HTLV-1 retrovirus remains poorly understood. We confirmed, in the present study, that the Tax-induced NF-κB activation involves the regulation of Bcl-3. Both knockdown and overexpression of Bcl-3 inhibit the Tax-induced NF-κB activation. Similarly, excessive Bcl-3 inhibits the NF-κB/DNA binding activity and significantly decreases Tax-induced p65 nuclear translocation. The present results demonstrate the pleiotropic roles of Bcl-3 in Tax-induced NF-κB activation and indicate that a balance in the aberrant Bcl-3 expression may be established to play an important role in the maintenance of proliferation and inhibition of apoptosis in HTLV-1-infected and ATL cells.

  19. Quantitative proteomic analysis of HIV-1 infected CD4+ T cells reveals an early host response in important biological pathways: Protein synthesis, cell proliferation, and T-cell activation

    SciTech Connect

    Navare, Arti T.; Sova, Pavel; Purdy, David E.; Weiss, Jeffrey M.; Wolf-Yadlin, Alejandro; Korth, Marcus J.; Chang, Stewart T.; Proll, Sean C.; Jahan, Tahmina A.; Krasnoselsky, Alexei L.; Palermo, Robert E.; Katze, Michael G.

    2012-07-20

    Human immunodeficiency virus (HIV-1) depends upon host-encoded proteins to facilitate its replication while at the same time inhibiting critical components of innate and/or intrinsic immune response pathways. To characterize the host cell response on protein levels in CD4+ lymphoblastoid SUP-T1 cells after infection with HIV-1 strain LAI, we used mass spectrometry (MS)-based global quantitation with iTRAQ (isobaric tag for relative and absolute quantification). We found 266, 60 and 22 proteins differentially expressed (DE) (P-value{<=}0.05) at 4, 8, and 20 hours post-infection (hpi), respectively, compared to time-matched mock-infected samples. The majority of changes in protein abundance occurred at an early stage of infection well before the de novo production of viral proteins. Functional analyses of these DE proteins showed enrichment in several biological pathways including protein synthesis, cell proliferation, and T-cell activation. Importantly, these early changes before the time of robust viral production have not been described before.

  20. Ureaplasma infection of cell cultures.

    PubMed Central

    Kotani, H; McGarrity, G J

    1986-01-01

    Studies were performed to characterize the effects of ureaplasmas in HeLa, 3T6, and CV-1 cell cultures. The ureaplasmas studied were human Ureaplasma urealyticum T960 (serotype VIII), bovine U. diversum T95, simian strain T167-2, ovine strain 1202, canine strain D1M-C, and feline strains 382 and FT2-B. FT2-B was the only ureaplasma to grow in the cell free culture medium, Dulbecco modified Eagle-Earle medium containing 10% fetal bovine serum. The growth pattern of the ureaplasmas varied in the different cell cultures, but each strain grew in at least two of the cell cultures, suggesting a requirement for a product of the cell culture and for low concentrations of urea. When growth occurred, organisms grew to concentrations that approached, but did not equal, those observed in 10B broth. Most, but not all, ureaplasmas grew quickly, reaching peak titers 2 days after infection. Canine strain D1M-C did not grow in 3T6, but showed rapid growth in HeLa and CV-1 cells, killing both cultures, In some systems, e.g., U. urealyticum T960 and simian strain T167-2, the infection persisted, and ureaplasmas could be recovered from cell cultures four passages after infection, when studies were terminated. The cell culture ureaplasmas grew on T agar, but not on mycoplasma agar medium. Images PMID:3699891

  1. Abortive infection of snakehead fish vesiculovirus in ZF4 cells was associated with the RLRs pathway activation by viral replicative intermediates.

    PubMed

    Wang, Wenwen; Asim, Muhammad; Yi, Lizhu; Hegazy, Abeer M; Hu, Xianqin; Zhou, Yang; Ai, Taoshan; Lin, Li

    2015-01-01

    Snakehead fish vesiculovirus (SHVV) is a negative strand RNA virus which can cause great economic losses in fish culture. To facilitate the study of SHVV-host interactions, the susceptibility of zebrafish embryonic fibroblast cell line (ZF4) to the SHVV was investigated in this report. The results showed that high amount of viral mRNAs and cRNAs were detected at the 3 h post-infection. However, the expressions of the viral mRNAs and cRNA were decreased dramatically after 6 h post-infection. In addition, the expressions of interferon (IFN) and interferon-induced GTP-binding protein Mx were all up regulated significantly at the late stage of the infection. Meanwhile, the expressions of Retinoic acid-inducible gene I (RIG-I) and Melanoma differentiation-associated gene 5 (MDA5) were also all up-regulated significantly during the infection. Two isoforms of DrLGP2 from zebrafish were also cloned and analyzed. Interestingly, the expression of DrLGP2a but not DrLGP2b was significantly up-regulated at both mRNA and protein levels, indicating that the two DrLGP2 isoforms might play different roles during the SHVV infection. Transfection experiment showed that viral replicative intermediates were required for the activation of IFN-α expression. Taken together, the abortive infection of SHVV in ZF4 cells was associated with the activation of RLRs pathway, which was activated by viral replicative intermediates. PMID:25794284

  2. Abortive Infection of Snakehead Fish Vesiculovirus in ZF4 Cells Was Associated with the RLRs Pathway Activation by Viral Replicative Intermediates

    PubMed Central

    Wang, Wenwen; Asim, Muhammad; Yi, Lizhu; Hegazy, Abeer M.; Hu, Xianqin; Zhou, Yang; Ai, Taoshan; Lin, Li

    2015-01-01

    Snakehead fish vesiculovirus (SHVV) is a negative strand RNA virus which can cause great economic losses in fish culture. To facilitate the study of SHVV-host interactions, the susceptibility of zebrafish embryonic fibroblast cell line (ZF4) to the SHVV was investigated in this report. The results showed that high amount of viral mRNAs and cRNAs were detected at the 3 h post-infection. However, the expressions of the viral mRNAs and cRNA were decreased dramatically after 6 h post-infection. In addition, the expressions of interferon (IFN) and interferon-induced GTP-binding protein Mx were all up regulated significantly at the late stage of the infection. Meanwhile, the expressions of Retinoic acid-inducible gene I (RIG-I) and Melanoma differentiation-associated gene 5 (MDA5) were also all up-regulated significantly during the infection. Two isoforms of DrLGP2 from zebrafish were also cloned and analyzed. Interestingly, the expression of DrLGP2a but not DrLGP2b was significantly up-regulated at both mRNA and protein levels, indicating that the two DrLGP2 isoforms might play different roles during the SHVV infection. Transfection experiment showed that viral replicative intermediates were required for the activation of IFN-α expression. Taken together, the abortive infection of SHVV in ZF4 cells was associated with the activation of RLRs pathway, which was activated by viral replicative intermediates. PMID:25794284

  3. Presence of Rheumatoid Factor during Chronic HCV Infection Is Associated with Expansion of Mature Activated Memory B-Cells that Are Hypo-Responsive to B-Cell Receptor Stimulation and Persist during the Early Stage of IFN Free Therapy

    PubMed Central

    Reyes-Avilés, Elane; Kostadinova, Lenche; Rusterholtz, Anne; Cruz-Lebrón, Angelica; Falck-Ytter, Yngve; Anthony, Donald D.

    2015-01-01

    Approximately half of those with chronic hepatitis C virus (HCV) infection have circulating rheumatoid factor (RF), and a portion of these individuals develop cryoglobulinemic vasculitis. B cell phenotype/function in relation to RF in serum has been unclear. We examined B cell subset distribution, activation state (CD86), cell cycle state (Ki67), and ex-vivo response to BCR, TLR9 and TLR7/8 stimulation, in chronic HCV-infected donors with or without RF, and uninfected donors. Mature-activated B-cells of HCV-infected donors had lower CD86 expression compared to uninfected donors, and in the presence of RF they also showed reduced CD86 expression in response to BCR and TLR9 stimulation. Additionally, mature activated memory B cells of HCV RF+ donors less commonly expressed Ki67+ than HCV RF- donors, and did not proliferate as well in response to BCR stimulation. Proportions of mature-activated B cells were enhanced, while naïve B-cells were lower in the peripheral blood of HCV-RF+ compared to RF- and uninfected donors. None of these parameters normalize by week 8 of IFN free direct acting antiviral (DAA) therapy in HCV RF+ donors, while in RF- donors, mature activated B cell proportions did normalize. These data indicate that while chronic HCV infection alone results in a lower state of activation in mature activated memory B cells, the presence of RF in serum is associated with a more pronounced state of unresponsiveness and an overrepresentation of these B cells in the blood. This phenotype persists at least during the early time window after removal of HCV from the host. PMID:26649443

  4. Intracellular demonstration of active TGFbeta1 in B cells and plasma cells of autoimmune mice. IgG-bound TGFbeta1 suppresses neutrophil function and host defense against Staphylococcus aureus infection.

    PubMed Central

    Caver, T E; O'Sullivan, F X; Gold, L I; Gresham, H D

    1996-01-01

    Infection remains a leading cause of morbidity and mortality in patients with SLE. To investigate this, previously we assessed the host defense status of autoimmune MRL/lpr mice and found that elaboration of active TGFbeta suppressed neutrophil function and decreased survival in response to Staphylococcus aureus infection. The purpose of the present work was to elucidate the molecular form and the cellular source of the active TGFbeta involved. Here, we report for the first time that TGFbeta1 is found in the active form inside B cells and plasma cells and that it circulates in the plasma complexed with IgG in two murine models of systemic autoimmunity and in some patients with SLE. IgG-bound active TGFbeta1 is many times more potent than uncomplexed active TGFbeta1 for suppression of neutrophil function in vitro and host defense against S. aureus infection in vivo. These data indicate that TGFbeta1 is in the active form inside B cells and plasma cells, that the formation of a complex of IgG and active TGFbeta1 is greatly accelerated in autoimmunity, and that this complex is extremely potent for suppression of PMN function and host defense against bacterial infection. PMID:8958212

  5. Interferon Regulator Factor 8 (IRF8) Limits Ocular Pathology during HSV-1 Infection by Restraining the Activation and Expansion of CD8+ T Cells

    PubMed Central

    Yu, Cheng-Rong; He, Chang; Mahdi, Rashid M.; Chan, Chi-Chao; Wang, Hongsheng; Morse, Herbert C.; Egwuagu, Charles E.

    2016-01-01

    Interferon Regulatory Factor-8 (IRF8) is constitutively expressed in monocytes and B cell lineages and plays important roles in immunity to pathogens and cancer. Although IRF8 expression is induced in activated T cells, the functional relevance of IRF8 in T cell-mediated immunity is not well understood. In this study, we used mice with targeted deletion of Irf8 in T-cells (IRF8KO) to investigate the role of IRF8 in T cell-mediated responses during herpes simplex virus 1 (HSV-1) infection of the eye. In contrast to wild type mice, HSV-1-infected IRF8KO mice mounted a more robust anti-HSV-1 immune response, which included marked expansion of HSV-1-specific CD8+ T cells, increased infiltration of inflammatory cells into the cornea and trigeminal ganglia (TG) and enhanced elimination of virus within the trigeminal ganglion. However, the consequence of the enhanced immunological response was the development of ocular inflammation, limbitis, and neutrophilic infiltration into the cornea of HSV-1-infected IRF8KO mice. Surprisingly, we observed a marked increase in virus-specific memory precursor effector cells (MPEC) in IRF8KO mice, suggesting that IRF8 might play a role in regulating the differentiation of effector CD8+ T cells to the memory phenotype. Together, our data suggest that IRF8 might play a role in restraining excess lymphocyte proliferation. Thus, modulating IRF8 levels in T cells can be exploited therapeutically to prevent immune-mediated ocular pathology during autoimmune and infectious diseases of the eye. PMID:27171004

  6. The Microvesicle Component of HIV-1 Inocula Modulates Dendritic Cell Infection and Maturation and Enhances Adhesion to and Activation of T Lymphocytes

    PubMed Central

    Mercier, Sarah K.; Donaghy, Heather; Botting, Rachel A.; Turville, Stuart G.; Harman, Andrew N.; Nasr, Najla; Ji, Hong; Kusebauch, Ulrike; Mendoza, Luis; Shteynberg, David; Sandgren, Kerrie; Simpson, Richard J.; Moritz, Robert L.; Cunningham, Anthony L.

    2013-01-01

    HIV-1 is taken up by immature monocyte derived dendritic cells (iMDDCs) into tetraspanin rich caves from which the virus can either be transferred to T lymphocytes or enter into endosomes resulting in degradation. HIV-1 binding and fusion with the DC membrane results in low level de novo infection that can also be transferred to T lymphocytes at a later stage. We have previously reported that HIV-1 can induce partial maturation of iMDDCs at both stages of trafficking. Here we show that CD45+ microvesicles (MV) which contaminate purified HIV-1 inocula due to similar size and density, affect DC maturation, de novo HIV-1 infection and transfer to T lymphocytes. Comparing iMDDCs infected with CD45-depleted HIV-1BaL or matched non-depleted preparations, the presence of CD45+ MVs was shown to enhance DC maturation and ICAM-1 (CD54) expression, which is involved in DC∶T lymphocyte interactions, while restricting HIV-1 infection of MDDCs. Furthermore, in the DC culture HIV-1 infected (p24+) MDDCs were more mature than bystander cells. Depletion of MVs from the HIV-1 inoculum markedly inhibited DC∶T lymphocyte clustering and the induction of alloproliferation as well as limiting HIV-1 transfer from DCs to T lymphocytes. The effects of MV depletion on these functions were reversed by the re-addition of purified MVs from activated but not non-activated SUPT1.CCR5-CL.30 or primary T cells. Analysis of the protein complement of these MVs and of these HIV-1 inocula before and after MV depletion showed that Heat Shock Proteins (HSPs) and nef were the likely DC maturation candidates. Recombinant HSP90α and β and nef all induced DC maturation and ICAM-1 expression, greater when combined. These results suggest that MVs contaminating HIV-1 released from infected T lymphocytes may be biologically important, especially in enhancing T cell activation, during uptake by DCs in vitro and in vivo, particularly as MVs have been detected in the circulation of HIV-1 infected subjects

  7. Kaposi's-sarcoma-associated-herpesvirus-activated dendritic cells promote HIV-1 trans-infection and suppress CD4{sup +} T cell proliferation

    SciTech Connect

    Liu, Wan; Qin, Yan; Bai, Lei; Lan, Ke; Wang, Jian-Hua

    2013-06-05

    Infection of Kaposi's sarcoma-associated herpesvirus (KSHV) is commonly occurred in AIDS patients. KSHV and HIV-1 act cooperatively in regulating infection with each other and in human carcinogenesis. Dendritic cells (DCs), as the pivotal cells in host immunity, may be modulated by both viruses, for immunoevasion and dissemination, therefore, the interaction between DCs and each virus has been a prior focus for pathogenesis elucidation. Here, we assessed the potential effect of KSHV on DC–HIV-1 interaction. We found that KSHV stimulation could promote maturation of monocyte-derived DCs (MDDCs) and impaired the ability of MDDCs to drive proliferation of resting CD4{sup +} T cells, demonstrating the immunosuppression induced by KSHV. More importantly, KSHV-stimulated MDDCs could capture more HIV-1 and efficiently transferred these infectious viruses to Hut/CCR5 T cell line. Our results reveal the novel modulation of DC-mediated HIV-1 dissemination by KSHV, and highlight the importance of studying DC–HIV-1 interaction to elucidate HIV/AIDS pathogenesis. - Highlights: ► KSHV impaired the ability of MDDCs to drive proliferation of resting CD4{sup +} T cells. ► KSHV stimulation matured MDDCs and enhanced HIV-1 endocytosis. ► KSHV stimulated MDDCs increased ICAM-1 expression and tighten contact with T cells. ► KSHV-stimulated MDDCs promoted HIV-1 trans-infection of CD4{sup +} T cells.

  8. Oral Cyclosporin A Inhibits CD4 T cell P-glycoprotein Activity in HIV-Infected Adults Initiating Treatment with Nucleoside Reverse Transcriptase Inhibitors

    PubMed Central

    Hulgan, Todd; Donahue, John P.; Smeaton, Laura; Pu, Minya; Wang, Hongying; Lederman, Michael M.; Smith, Kimberly; Valdez, Hernan; Pilcher, Christopher; Haas, David W.

    2010-01-01

    Purpose P-glycoprotein limits tissue penetration of many antiretroviral drugs. We characterized effects of the P-glycoprotein substrate cyclosporin A on T cell P-glycoprotein activity in HIV-infected AIDS Clinical Trials Group study A5138 participants. Methods We studied P-glycoprotein activity on CD4 and CD8 T cells in 16 participants randomized to receive oral cyclosporin A (n=9) or not (n=7) during initiation antiretroviral therapy (ART) that did not include protease or non-nucleoside reverse transcriptase inhibitors. Results CD4 T cell P-glycoprotein activity decreased by a median of 8 percentage points with cyclosporin A/ART (difference between cyclosporin A/ART versus ART only P=0.001). Plasma trough cyclosporin A concentrations correlated with change in P-glycoprotein activity in several T cell subsets. Conclusions Oral cyclosporin A can inhibit peripheral blood CD4 T cell P-glycoprotein activity. Targeted P-glycoprotein inhibition might enhance delivery of ART to T cells. PMID:19779705

  9. Plasmodium falciparum Infection of Human Volunteers Activates Monocytes and CD16+ Dendritic Cells and Induces Upregulation of CD16 and CD1c Expression

    PubMed Central

    Teirlinck, Anne C.; Roestenberg, Meta; Bijker, Else M.; Hoffman, Stephen L.

    2015-01-01

    Antigen-presenting cells (APCs) are key players in the induction and regulation of immune responses. In Plasmodium falciparum malaria, determination of which cells and pathways are activated in the network of APCs remains elusive. We therefore investigated the effects of a controlled human malaria infection in healthy, malaria-naive volunteers on the subset composition and activation status of dendritic cells (DCs) and monocytes. While subsets of monocytes increased in frequency during blood-stage infection, DC frequencies remained largely stable. Activation markers classically associated with peptide presentation to and priming of αβT cells, HLA-DR and CD86, were upregulated in monocytes and inflammatory CD16 myeloid DCs (mDCs) but not in the classical CD1c, BDCA2, or BDCA3 DC subsets. In addition, these activated APC subsets showed increased expression of CD1c, which is involved in glycolipid antigen presentation, and of the immune complex binding Fcγ receptor III (CD16). Our data show that P. falciparum asexual parasites do not activate classical DC subsets but instead activate mainly monocytes and inflammatory CD16 mDCs and appear to prime alternative activation pathways via induction of CD16 and/or CD1c. Changes in expression of these surface molecules might increase antigen capture and enhance glycolipid antigen presentation in addition to the classical major histocompatibility complex class II (MHC-II) peptide presentation and thereby contribute to the initiation of T-cell responses in malaria. (This study has been registered at Clinicaltrials.gov under registration no. NCT01086917.) PMID:26169270

  10. NK Cell Activity Differs between Patients with Localized and Diffuse Cutaneous Leishmaniasis Infected with Leishmania mexicana: A Comparative Study of TLRs and Cytokines

    PubMed Central

    Cañeda-Guzmán, Isabel Cristina; Salaiza-Suazo, Norma; Fernández-Figueroa, Edith A.; Carrada-Figueroa, Georgina; Aguirre-García, Magdalena; Becker, Ingeborg

    2014-01-01

    Leishmania mexicana causes localized (LCL) or diffuse cutaneous leishmaniasis (DCL). The cause of dissemination in DCL remains unknown, yet NK cells possibly play a role in activating leishmanicidal mechanisms during innate and adaptive immune responses. We had previously shown that Leishmania lipophosphoglycan (LPG) is a ligand for TLR2, activating human NK cells. We have now analyzed NK cells in LCL and DCL patients. NK numbers and effector mechanisms differed drastically between both groups of patients: DCL patients showed reduced NK cell numbers; diminished IFN-γ and TNF-α production; and lower TLR2, TLR1, and TLR6 expression as compared to LCL patients. The altered protein expression found in NK cells of DCL patients correlated with their down-regulation of IFN-γ gene expression in LPG-stimulated and non-stimulated cells as compared to LCL patients. NK cell response was further analyzed according to gender, age, and disease evolution in LCL patients showing that female patients produced higher IFN-γ levels throughout the disease progression, whereas TLR2 expression diminished in both genders with prolonged disease evolution and age. We furthermore show the activation pathway of LPG binding to TLR2 and demonstrated that TLR2 forms immunocomplexes with TLR1 and TLR6. In addition to the reduced NK cell numbers in peripheral blood, DCL patients also showed reduced NK cell numbers in the lesions. They were randomly scattered within the lesions, showing diminished cytokine production, which contrasts with those of LCL lesions, where NK cells produced IFN-γ and TNF-α and were found within organized granulomas. We conclude that in DCL patients the reduced NK-cell numbers and their diminished activity, evidenced by low TLR expression and low cytokine production, are possibly involved in the severity of the disease. Our results provide new information on the contribution of NK cells in Leishmania infections of the human host. PMID:25397678

  11. NK cell activity differs between patients with localized and diffuse cutaneous leishmaniasis infected with Leishmania mexicana: a comparative study of TLRs and cytokines.

    PubMed

    Cañeda-Guzmán, Isabel Cristina; Salaiza-Suazo, Norma; Fernández-Figueroa, Edith A; Carrada-Figueroa, Georgina; Aguirre-García, Magdalena; Becker, Ingeborg

    2014-01-01

    Leishmania mexicana causes localized (LCL) or diffuse cutaneous leishmaniasis (DCL). The cause of dissemination in DCL remains unknown, yet NK cells possibly play a role in activating leishmanicidal mechanisms during innate and adaptive immune responses. We had previously shown that Leishmania lipophosphoglycan (LPG) is a ligand for TLR2, activating human NK cells. We have now analyzed NK cells in LCL and DCL patients. NK numbers and effector mechanisms differed drastically between both groups of patients: DCL patients showed reduced NK cell numbers; diminished IFN-γ and TNF-α production; and lower TLR2, TLR1, and TLR6 expression as compared to LCL patients. The altered protein expression found in NK cells of DCL patients correlated with their down-regulation of IFN-γ gene expression in LPG-stimulated and non-stimulated cells as compared to LCL patients. NK cell response was further analyzed according to gender, age, and disease evolution in LCL patients showing that female patients produced higher IFN-γ levels throughout the disease progression, whereas TLR2 expression diminished in both genders with prolonged disease evolution and age. We furthermore show the activation pathway of LPG binding to TLR2 and demonstrated that TLR2 forms immunocomplexes with TLR1 and TLR6. In addition to the reduced NK cell numbers in peripheral blood, DCL patients also showed reduced NK cell numbers in the lesions. They were randomly scattered within the lesions, showing diminished cytokine production, which contrasts with those of LCL lesions, where NK cells produced IFN-γ and TNF-α and were found within organized granulomas. We conclude that in DCL patients the reduced NK-cell numbers and their diminished activity, evidenced by low TLR expression and low cytokine production, are possibly involved in the severity of the disease. Our results provide new information on the contribution of NK cells in Leishmania infections of the human host. PMID:25397678

  12. Rapid activation of spleen dendritic cell subsets following lymphocytic choriomeningitis virus infection of mice: analysis of the involvement of type 1 IFN.

    PubMed

    Montoya, Maria; Edwards, Matthew J; Reid, Delyth M; Borrow, Persephone

    2005-02-15

    In this study, we report the dynamic changes in activation and functions that occur in spleen dendritic cell (sDC) subsets following infection of mice with a natural murine pathogen, lymphocytic choriomeningitis virus (LCMV). Within 24 h postinfection (pi), sDCs acquired the ability to stimulate naive LCMV-specific CD8+ T cells ex vivo. Conventional (CD11chigh CD8+ and CD4+) sDC subsets rapidly up-regulated expression of costimulatory molecules and began to produce proinflammatory cytokines. Their tendency to undergo apoptosis ex vivo simultaneously increased, and in vivo the number of conventional DCs in the spleen decreased markedly, dropping approximately 2-fold by day 3 pi. Conversely, the number of plasmacytoid (CD11clowB220+) DCs in the spleen increased, so that they constituted almost 40% of sDCs by day 3 pi. Type 1 IFN production was up-regulated in plasmacytoid DCs by 24 h pi. Analysis of DC activation and maturation in mice unable to respond to type 1 IFNs implicated these cytokines in driving infection-associated phenotypic activation of conventional DCs and their enhanced tendency to undergo apoptosis, but also indicated the existence of type 1 IFN-independent pathways for the functional maturation of DCs during LCMV infection. PMID:15699111

  13. Comparative proteomic analyses demonstrate enhanced interferon and STAT-1 activation in reovirus T3D-infected HeLa cells

    PubMed Central

    Ezzati, Peyman; Komher, Krysten; Severini, Giulia; Coombs, Kevin M.

    2015-01-01

    As obligate intracellular parasites, viruses are exclusively and intimately dependent upon their host cells for replication. During replication viruses induce profound changes within cells, including: induction of signaling pathways, morphological changes, and cell death. Many such cellular perturbations have been analyzed at the transcriptomic level by gene arrays and recent efforts have begun to analyze cellular proteomic responses. We recently described comparative stable isotopic (SILAC) analyses of reovirus, strain type 3 Dearing (T3D)-infected HeLa cells. For the present study we employed the complementary labeling strategy of iTRAQ (isobaric tags for relative and absolute quantitation) to examine HeLa cell changes induced by T3D, another reovirus strain, type 1 Lang, and UV-inactivated T3D (UV-T3D). Triplicate replicates of cytosolic and nuclear fractions identified a total of 2375 proteins, of which 50, 57, and 46 were significantly up-regulated, and 37, 26, and 44 were significantly down-regulated by T1L, T3D, and UV-T3D, respectively. Several pathways, most notably the Interferon signaling pathway and the EIF2 and ILK signaling pathways, were induced by virus infection. Western blots confirmed that cells were more strongly activated by live T3D as demonstrated by elevated levels of key proteins like STAT-1, ISG-15, IFIT-1, IFIT-3, and Mx1. This study expands our understanding of reovirus-induced host responses. PMID:25905045

  14. Brucella abortus-infected B cells induce osteoclastogenesis.

    PubMed

    Pesce Viglietti, Ayelén Ivana; Arriola Benitez, Paula Constanza; Giambartolomei, Guillermo Hernán; Delpino, María Victoria

    2016-09-01

    Brucella abortus is an intracellular bacterium that establishes lifelong infections in livestock and humans although the mechanisms of its chronicity are poorly understood. Activated B cells have long lifespan and B. abortus infection activates B cells. Our results indicate that the direct infection of B cells with B. abortus induced matrix metalloproteinase-9 (MMP-9), receptor activator for NF κB ligand (RANKL), tumor necrosis factor (TNF)-α and interleukin (IL)-6 secretion. In addition, supernatants from B. abortus-infected B cells induced bone marrow-derived monocytes to undergo osteoclastogenesis. Using osteoprotegerin, RANKL's decoy receptor, we determined that RANKL is involved in osteoclastogenesis induced by supernatants from B. abortus-infected B cells. The results presented here shed light on how the interactions of B. abortus with B cells may have a role in the pathogenesis of brucellar osteoarticular disease.

  15. Stem Cell Transplant Patients and Fungal Infections

    MedlinePlus

    ... Foodborne, Waterborne, and Environmental Diseases Mycotic Diseases Branch Stem Cell Transplant Patients and Fungal Infections Recommend on Facebook ... Mold . Top of Page Preventing fungal infections in stem cell transplant patients Fungi are difficult to avoid because ...

  16. I kappa B kinase alpha (IKKα) activity is required for functional maturation of dendritic cells and acquired immunity to infection.

    PubMed

    Mancino, Alessandra; Habbeddine, Mohamed; Johnson, Ella; Luron, Lionel; Bebien, Magali; Memet, Sylvie; Fong, Carol; Bajenoff, Marc; Wu, Xuefeng; Karin, Michael; Caamano, Jorge; Chi, Hongbo; Seed, Michael; Lawrence, Toby

    2013-03-20

    Dendritic cells (DC) are required for priming antigen-specific T cells and acquired immunity to many important human pathogens, including Mycobacteriuim tuberculosis (TB) and influenza. However, inappropriate priming of auto-reactive T cells is linked with autoimmune disease. Understanding the molecular mechanisms that regulate the priming and activation of naïve T cells is critical for development of new improved vaccines and understanding the pathogenesis of autoimmune diseases. The serine/threonine kinase IKKα (CHUK) has previously been shown to have anti-inflammatory activity and inhibit innate immunity. Here, we show that IKKα is required in DC for priming antigen-specific T cells and acquired immunity to the human pathogen Listeria monocytogenes. We describe a new role for IKKα in regulation of IRF3 activity and the functional maturation of DC. This presents a unique role for IKKα in dampening inflammation while simultaneously promoting adaptive immunity that could have important implications for the development of new vaccine adjuvants and treatment of autoimmune diseases.

  17. Physcomitrella patens activates reinforcement of the cell wall, programmed cell death and accumulation of evolutionary conserved defense signals...upon Botrytis cinerea infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The moss Physcomitrella patens is an evolutionarily basal model system suitable to analyze plant defense responses activated after pathogen assault. Upon infection with the necrotroph Botrytis cinerea (B. cinerea), several defense mechanisms are induced in P. patens, including the fortification of t...

  18. Dengue-2 and yellow fever 17DD viruses infect human dendritic cells, resulting in an induction of activation markers, cytokines and chemokines and secretion of different TNF-α and IFN-α profiles.

    PubMed

    Gandini, Mariana; Reis, Sonia Regina Nogueira Ignacio; Torrentes-Carvalho, Amanda; Azeredo, Elzinandes Leal; Freire, Marcos da Silva; Galler, Ricardo; Kubelka, Claire Fernandes

    2011-08-01

    Flaviviruses cause severe acute febrile and haemorrhagic infections, including dengue and yellow fever and the pathogenesis of these infections is caused by an exacerbated immune response. Dendritic cells (DCs) are targets for dengue virus (DENV) and yellow fever virus (YF) replication and are the first cell population to interact with these viruses during a natural infection, which leads to an induction of protective immunity in humans. We studied the infectivity of DENV2 (strain 16681), a YF vaccine (YF17DD) and a chimeric YF17D/DENV2 vaccine in monocyte-derived DCs in vitro with regard to cell maturation, activation and cytokine production. Higher viral antigen positive cell frequencies were observed for DENV2 when compared with both vaccine viruses. Flavivirus-infected cultures exhibited dendritic cell activation and maturation molecules. CD38 expression on DCs was enhanced for both DENV2 and YF17DD, whereas OX40L expression was decreased as compared to mock-stimulated cells, suggesting that a T helper 1 profile is favoured. Tumor necrosis factor (TNF)-α production in cell cultures was significantly higher in DENV2-infected cultures than in cultures infected with YF17DD or YF17D/DENV. In contrast, the vaccines induced higher IFN-α levels than DENV2. The differential cytokine production indicates that DENV2 results in TNF induction, which discriminates it from vaccine viruses that preferentially stimulate interferon expression. These differential response profiles may influence the pathogenic infection outcome.

  19. Chronic rabies virus infection of cell cultures.

    PubMed

    Wiktor, T J; Clark, H F

    1972-12-01

    Exposure of both mammalian and reptilian cells in tissue culture to different strains of fixed rabies virus resulted in a carrier type of infection. No cytopathic effect was observed in either type of culture; infected cultures could be maintained by cell transfer for unlimited numbers of passages. A consistent pattern of cyclically rising and falling levels of viral infection was observed by fluorescent-antibody staining techniques and by titration of released infectious virus. Resistance to super-infection by vesicular stomatis virus and the production of an interferon-like substance by infected cells indicated that the maintenance of a carrier type of infection may be interferon-mediated. The degree of susceptibility of rabies-infected cells to immunolysis by antirabies antibody in the presence of complement was found to be correlated with the amount of virus maturation occurring by budding through the cell membrane and not with the presence of immunofluorescent antigen in the cytoplasm of infected cells.

  20. Long-Term Effects of Highly Active Antiretroviral Therapy on CD4+ Cell Evolution among Children and Adolescents Infected with HIV: 5 Years and Counting

    PubMed Central

    Patel, Kunjal; Hernán, Miguel A.; Williams, Paige L.; Seeger, John D.; McIntosh, Kenneth; Van Dyke, Russell B.; Seage, George R.

    2011-01-01

    Background Lower percentages of CD4+ T lymphocytes are associated with adverse clinical outcomes among children and adolescents infected with human immunodeficiency virus (HIV). CD4+ lymphocyte percentage generally increases with receipt of highly active antiretroviral therapy (HAART), but long-term follow-up is required to assess whether these increases in CD4+ cell percentage are maintained and whether they lead to normal CD4+ cell percentages in children with severe immunosuppression. Methods The study population included 1236 children and adolescents perinatally infected with HIV who were enrolled in a US-based multicenter prospective cohort study (Pediatric AIDS Clinical Trials Group 219/219C) and who were not receiving HAART at study initiation. We estimated the effects of HAART, HAART with protease inhibitors, and HAART with nonnucleoside reverse-transcriptase inhibitors on CD4+ cell percentage, using marginal structural models to account for confounding by severity. Results Initiation of any type of HAART increased CD4+ cell percentage by 2.34% (95% confidence interval, 1.35%–3.33%) in the first year, relative to noninitiation of HAART. The substantial increases in CD4+ cell percentage observed after the first year of experience with these combination therapies were followed by relatively smaller increases that continued for 5 years after initiation. Although larger increases in CD4+ cell percentage were observed among children with a greater degree of immunosuppression at baseline, the mean CD4+ cell percentage after 5 years of HAART did not reach normal levels. Conclusions Our study supports the initiation of HAART in children before severe immunosuppression occurs for long-term maintenance of normal CD4+ cell percentages. This beneficial result must be weighed against the evidence of potential adverse events associated with the prolonged use of such therapy. PMID:18426371

  1. Active Immunization with Extracellular Vesicles Derived from Staphylococcus aureus Effectively Protects against Staphylococcal Lung Infections, Mainly via Th1 Cell-Mediated Immunity.

    PubMed

    Choi, Seng Jin; Kim, Min-Hye; Jeon, Jinseong; Kim, Oh Youn; Choi, Youngwoo; Seo, Jihye; Hong, Sung-Wook; Lee, Won-Hee; Jeon, Seong Gyu; Gho, Yong Song; Jee, Young-Koo; Kim, Yoon-Keun

    2015-01-01

    Staphylococcus aureus is an important pathogenic bacterium that causes various infectious diseases. Extracellular vesicles (EVs) released from S. aureus contain bacterial proteins, nucleic acids, and lipids. These EVs can induce immune responses leading to similar symptoms as during staphylococcal infection condition and have the potential as vaccination agent. Here, we show that active immunization (vaccination) with S. aureus-derived EVs induce adaptive immunity of antibody and T cell responses. In addition, these EVs have the vaccine adjuvant ability to induce protective immunity such as the up-regulation of co-stimulatory molecules and the expression of T cell polarizing cytokines in antigen-presenting cells. Moreover, vaccination with S. aureus EVs conferred protection against lethality induced by airway challenge with lethal dose of S. aureus and also pneumonia induced by the administration of sub-lethal dose of S. aureus. These protective effects were also found in mice that were adoptively transferred with splenic T cells isolated from S. aureus EV-immunized mice, but not in serum transferred mice. Furthermore, this protective effect of S. aureus EVs was significantly reduced by the absence of interferon-gamma, but not by the absence of interleukin-17. Together, the study herein suggests that S. aureus EVs are a novel vaccine candidate against S. aureus infections, mainly via Th1 cellular response.

  2. TNF-Mediated Restriction of Arginase 1 Expression in Myeloid Cells Triggers Type 2 NO Synthase Activity at the Site of Infection

    PubMed Central

    Obermeyer, Stephanie; König, Till; Kling, Jessica C.; Ribechini, Eliana; Dudziak, Diana; Mougiakakos, Dimitrios; Murray, Peter J.; Ostuni, Renato; Körner, Heinrich; Bogdan, Christian

    2016-01-01

    Neutralization or deletion of tumor necrosis factor (TNF) causes loss of control of intracellular pathogens in mice and humans, but the underlying mechanisms are incompletely understood. Here, we found that TNF antagonized alternative activation of macrophages and dendritic cells by IL-4. TNF inhibited IL-4-induced arginase (Arg) 1 expression by decreasing histone acetylation, without affecting STAT6 phosphorylation and nuclear translocation. In Leishmania major-infected C57BL/6 wild-type mice, type 2 nitric oxide (NO) synthase (NOS2) was detected in inflammatory dendritic cells/macrophages, some of which coexpressed Arg1. In TNF-deficient mice Arg1 was hyperexpressed causing an impaired production of NO in situ. A similar phenotype was seen in L. major-infected BALB/c mice. Arg1 deletion in hematopoietic cells protected these mice from an otherwise lethal disease, although their disease-mediating T cell response (Th2, Treg) was maintained. Thus, deletion or TNF-mediated restriction of Arg1 unleashes the production of NO by NOS2 which is critical for pathogen control. PMID:27117406

  3. TNF-Mediated Restriction of Arginase 1 Expression in Myeloid Cells Triggers Type 2 NO Synthase Activity at the Site of Infection.

    PubMed

    Schleicher, Ulrike; Paduch, Katrin; Debus, Andrea; Obermeyer, Stephanie; König, Till; Kling, Jessica C; Ribechini, Eliana; Dudziak, Diana; Mougiakakos, Dimitrios; Murray, Peter J; Ostuni, Renato; Körner, Heinrich; Bogdan, Christian

    2016-05-01

    Neutralization or deletion of tumor necrosis factor (TNF) causes loss of control of intracellular pathogens in mice and humans, but the underlying mechanisms are incompletely understood. Here, we found that TNF antagonized alternative activation of macrophages and dendritic cells by IL-4. TNF inhibited IL-4-induced arginase 1 (Arg1) expression by decreasing histone acetylation, without affecting STAT6 phosphorylation and nuclear translocation. In Leishmania major-infected C57BL/6 wild-type mice, type 2 nitric oxide (NO) synthase (NOS2) was detected in inflammatory dendritic cells or macrophages, some of which co-expressed Arg1. In TNF-deficient mice, Arg1 was hyperexpressed, causing an impaired production of NO in situ. A similar phenotype was seen in L. major-infected BALB/c mice. Arg1 deletion in hematopoietic cells protected these mice from an otherwise lethal disease, although their disease-mediating T cell response (Th2, Treg) was maintained. Thus, deletion or TNF-mediated restriction of Arg1 unleashes the production of NO by NOS2, which is critical for pathogen control.

  4. Heparinase I-specific disaccharide unit of heparin is a key structure but insufficient for exerting anti-prion activity in prion-infected cells.

    PubMed

    Teruya, Kenta; Wakao, Masahiro; Sato, Masaki; Hamanaka, Taichi; Nishizawa, Keiko; Funayama, Yukino; Sakasegawa, Yuji; Suda, Yasuo; Doh-ura, Katsumi

    2015-05-15

    Glycosaminoglycans reportedly play important roles in prion formation, but because of their structural complexity, the chemical structures affecting prion formation have not been fully evaluated. Here, we compared two types of low molecular weight heparins and found that heparinase I-sensitive structures influenced anti-prion activity in prion-infected cells. Surface plasmon resonance analyses showed significant binding of a representative heparinase I substrate disaccharide unit, GlcNS6S-IdoA2S, to recombinant prion protein (PrP) fragments, such as full-length PrP23-231 and N-terminal domain PrP23-89, but not to PrP89-230. This binding was competitively inhibited by heparin or pentosan polysulfate, but not by Cu(2+). These PrP binding profiles of the disaccharide unit are consistent with those previously reported for heparin. However, synthetic compounds comprising disaccharide unit alone or its multimers exhibited no anti-prion activity in prion-infected cells. Consequently, the findings suggest that the heparin disaccharide unit that binds to the N-terminal region of PrP is a key structure, but it is insufficient for exerting anti-prion activity.

  5. Parvovirus infection-induced cell death and cell cycle arrest

    PubMed Central

    Chen, Aaron Yun; Qiu, Jianming

    2011-01-01

    The cytopathic effects induced during parvovirus infection have been widely documented. Parvovirus infection-induced cell death is often directly associated with disease outcomes (e.g., anemia resulting from loss of erythroid progenitors during parvovirus B19 infection). Apoptosis is the major form of cell death induced by parvovirus infection. However, nonapoptotic cell death, namely necrosis, has also been reported during infection of the minute virus of mice, parvovirus H-1 and bovine parvovirus. Recent studies have revealed multiple mechanisms underlying the cell death during parvovirus infection. These mechanisms vary in different parvoviruses, although the large nonstructural protein (NS)1 and the small NS proteins (e.g., the 11 kDa of parvovirus B19), as well as replication of the viral genome, are responsible for causing infection-induced cell death. Cell cycle arrest is also common, and contributes to the cytopathic effects induced during parvovirus infection. While viral NS proteins have been indicated to induce cell cycle arrest, increasing evidence suggests that a cellular DNA damage response triggered by an invading single-stranded parvoviral genome is the major inducer of cell cycle arrest in parvovirus-infected cells. Apparently, in response to infection, cell death and cell cycle arrest of parvovirus-infected cells are beneficial to the viral cell lifecycle (e.g., viral DNA replication and virus egress). In this article, we will discuss recent advances in the understanding of the mechanisms underlying parvovirus infection-induced cell death and cell cycle arrest. PMID:21331319

  6. Elevation of Alanine Aminotransferase Activity Occurs after Activation of the Cell-Death Signaling Initiated by Pattern-Recognition Receptors ‎but before Activation of Cytolytic Effectors in NK or CD8+ T Cells in the Liver During Acute HCV Infection

    PubMed Central

    Choi, Youkyung H.; Jin, Nancy; Kelly, Fiona; Sakthivel, SenthilKumar K.; Yu, Tianwei

    2016-01-01

    Pattern-recognition receptors (PRRs) promote host defenses against HCV infection by binding to their corresponding adapter molecules leading to the initiation of innate immune responses including cell death. We investigated the expression of PRR genes, biomarkers of liver cell-death, and T cell and NK cell activation/inhibition-related genes in liver and serum obtained from three experimentally infected chimpanzees with acute HCV infection, and analyzed the correlation between gene expression levels and clinical profiles. Our results showed that expression of hepatic RIG-I, TLR3, TLR7, 2OAS1, and CXCL10 mRNAs was upregulated as early as 7 days post-inoculation and peaked 12 to 83 days post-inoculation. All of the three HCV infected chimpanzees exhibited significant elevations of serum alanine aminotransferase (ALT) activity between 70 and 95 days after inoculation. Elevated levels of serum cytokeratin 18 (CK-18) and caspases 3 and 7 activity coincided closely with the rise of ALT activity, and were preceded by significant increases in levels of caspase 3 and caspase 7 mRNAs in the liver. Particularly we found that significant positive auto-correlations were observed between RIG-I, TLR3, CXCL10, 2OAS1, and PD-L1 mRNA and ALT activity at 3 to 12 days before the peak of ALT activity. However, we observed substantial negative auto-correlations between T cell and NK cell activation/inhibition-related genes and ALT activity at 5 to 32 days after the peak of ALT activity. Our results indicated cell death signaling is preceded by early induction of RIG-I, TLR3, 2OAS1, and CXCL10 mRNAs which leads to elevation of ALT activity and this signaling pathway occurs before the activation of NK and T cells during acute HCV infection. Our study suggests that PRRs and type I IFN response may play a critical role in development of liver cell injury related to viral clearance during acute HCV infection. PMID:27788241

  7. Inactivated E. coli transformed with plasmids that produce dsRNA against infectious salmon anemia virus hemagglutinin show antiviral activity when added to infected ASK cells

    PubMed Central

    García, Katherine; Ramírez-Araya, Sebastián; Díaz, Álvaro; Reyes-Cerpa, Sebastián; Espejo, Romilio T.; Higuera, Gastón; Romero, Jaime

    2015-01-01

    Infectious salmon anemia virus (ISAV) has caused great losses to the Chilean salmon industry, and the success of prevention and treatment strategies is uncertain. The use of RNA interference (RNAi) is a promising approach because during the replication cycle, the ISAV genome must be transcribed to mRNA in the cytoplasm. We explored the capacity of E. coli transformed with plasmids that produce double-stranded RNA (dsRNA) to induce antiviral activity when added to infected ASK cells. We transformed the non-pathogenic Escherichia coli HT115 (DE3) with plasmids that expressed highly conserved regions of the ISAV genes encoding the nucleoprotein (NP), fusion (F), hemagglutinin (HE), and matrix (M) proteins as dsRNA, which is the precursor of the RNAi mechanism. The inactivated transformed bacteria carrying dsRNA were tested for their capacity to silence the target ISAV genes, and the dsRNA that were able to inhibit gene expression were subsequently tested for their ability to attenuate the cytopathic effect (CPE) and reduce the viral load. Of the four target genes tested, inactivated E. coli transformed with plasmids producing dsRNA targeting HE showed antiviral activity when added to infected ASK cells. PMID:25932022

  8. Inactivated E. coli transformed with plasmids that produce dsRNA against infectious salmon anemia virus hemagglutinin show antiviral activity when added to infected ASK cells.

    PubMed

    García, Katherine; Ramírez-Araya, Sebastián; Díaz, Álvaro; Reyes-Cerpa, Sebastián; Espejo, Romilio T; Higuera, Gastón; Romero, Jaime

    2015-01-01

    Infectious salmon anemia virus (ISAV) has caused great losses to the Chilean salmon industry, and the success of prevention and treatment strategies is uncertain. The use of RNA interference (RNAi) is a promising approach because during the replication cycle, the ISAV genome must be transcribed to mRNA in the cytoplasm. We explored the capacity of E. coli transformed with plasmids that produce double-stranded RNA (dsRNA) to induce antiviral activity when added to infected ASK cells. We transformed the non-pathogenic Escherichia coli HT115 (DE3) with plasmids that expressed highly conserved regions of the ISAV genes encoding the nucleoprotein (NP), fusion (F), hemagglutinin (HE), and matrix (M) proteins as dsRNA, which is the precursor of the RNAi mechanism. The inactivated transformed bacteria carrying dsRNA were tested for their capacity to silence the target ISAV genes, and the dsRNA that were able to inhibit gene expression were subsequently tested for their ability to attenuate the cytopathic effect (CPE) and reduce the viral load. Of the four target genes tested, inactivated E. coli transformed with plasmids producing dsRNA targeting HE showed antiviral activity when added to infected ASK cells.

  9. Activation of a beta-galactosidase recombinant provirus: application to titration of human immunodeficiency virus (HIV) and HIV-infected cells.

    PubMed

    Rocancourt, D; Bonnerot, C; Jouin, H; Emerman, M; Nicolas, J F

    1990-06-01

    A quantitative bioassay for human immunodeficiency viruses has been developed on the basis of the ability of the tat gene to transactivate the expression of an integrated beta-galactosidase gene in a HeLa-CD4+ cell line. Infection by a single virion of HIV-1 or HIV-2 corresponds to a unique blue syncytium or a cell cluster detected after fixation and addition of 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (a beta-galactosidase substrate). The number of infected lymphoid cells in a culture (stimulated human peripheral blood lymphocytes and cell lines) can also be quantified by cell-to-cell transmission of HIV into the HeLa-CD4(+)-beta-galactosidase monolayer. Infections by simian immunodeficiency viruses are similarly detected. This assay has been used to determine the dose response of drugs, the half-life of HIV at 37 degrees C, and the appearance of infectious particles after virus infection.

  10. Dengue Virus Infection Perturbs Lipid Homeostasis in Infected Mosquito Cells

    SciTech Connect

    Perera, Rushika M.; Riley, Catherine; Isaac, Georgis; Hopf- Jannasch, Amber; Moore, Ronald J.; Weitz, Karl K.; Pasa-Tolic, Ljiljana; Metz, Thomas O.; Adamec, Jiri; Kuhn, Richard J.

    2012-03-22

    Dengue virus causes {approx}50-100 million infections per year and thus is considered one of the most aggressive arthropod-borne human pathogen worldwide. During its replication, dengue virus induces dramatic alterations in the intracellular membranes of infected cells. This phenomenon is observed both in human and vector-derived cells. Using high-resolution mass spectrometry of mosquito cells, we show that this membrane remodeling is directly linked to a unique lipid repertoire induced by dengue virus infection. Specifically, 15% of the metabolites detected were significantly different between DENV infected and uninfected cells while 85% of the metabolites detected were significantly different in isolated replication complex membranes. Furthermore, we demonstrate that intracellular lipid redistribution induced by the inhibition of fatty acid synthase, the rate-limiting enzyme in lipid biosynthesis, is sufficient for cell survival but is inhibitory to dengue virus replication. Lipids that have the capacity to destabilize and change the curvature of membranes as well as lipids that change the permeability of membranes are enriched in dengue virus infected cells. Several sphingolipids and other bioactive signaling molecules that are involved in controlling membrane fusion, fission, and trafficking as well as molecules that influence cytoskeletal reorganization are also up regulated during dengue infection. These observations shed light on the emerging role of lipids in shaping the membrane and protein environments during viral infections and suggest membrane-organizing principles that may influence virus-induced intracellular membrane architecture.

  11. Activation of the 2-5OAS/RNase L pathway in CVB1 or HAV/18f infected FRhK-4 cells does not require induction of OAS1 or OAS2 expression

    SciTech Connect

    Kulka, Michael; Calvo, Mona S.; Ngo, Diana T.; Wales, Samantha Q.; Goswami, Biswendu B.

    2009-05-25

    The latent, constitutively expressed protein RNase L is activated in coxsackievirus and HAV strain 18f infected FRhK-4 cells. Endogenous oligoadenylate synthetase (OAS) from uninfected and virus infected cell extracts synthesizes active forms of the triphosphorylated 2-5A oligomer (the only known activator of RNase L) in vitro and endogenous 2-5A is detected in infected cell extracts. However, only the largest OAS isoform, OAS3, is readily detected throughout the time course of infection. While IFNbeta treatment results in an increase in the level of all three OAS isoforms in FRhK-4 cells, IFNbeta pretreatment does not affect the temporal onset or enhancement of RNase L activity nor inhibit virus replication. Our results indicate that CVB1 and HAV/18f activate the 2-5OAS/RNase L pathway in FRhK-4 cells during permissive infection through endogenous levels of OAS, but contrary to that reported for some picornaviruses, CVB1 and HAV/18f replication is insensitive to this activated antiviral pathway.

  12. Induction of an Epithelial Integrin αvβ6 in Human Cytomegalovirus-Infected Endothelial Cells Leads to Activation of Transforming Growth Factor-β1 and Increased Collagen Production

    PubMed Central

    Tabata, Takako; Kawakatsu, Hisaaki; Maidji, Ekaterina; Sakai, Takao; Sakai, Keiko; Fang-Hoover, June; Aiba, Motohiko; Sheppard, Dean; Pereira, Lenore

    2008-01-01

    Human cytomegalovirus (CMV) infection is a major cause of morbidity in immunosuppressed individuals, and congenital CMV infection is a leading cause of birth defects in newborns. Infection with pathogenic viral strains alters cell-cell and cell-matrix interactions, affecting extracellular matrix remodeling and endothelial cell migration. The multifunctional cytokine transforming growth factor (TGF)-β1 regulates cell proliferation, differentiation, and extracellular matrix remodeling. Secreted as a latent protein complex, TGF-β1 requires activation before binding to receptors that phosphorylate intracellular effectors. TGF-β1 is activated by integrin αvβ6, which is strongly induced in the epithelium by injury and inflammation but has not previously been found in endothelial cells. Here, we report that CMV infection induces integrin αvβ6 expression in endothelial cells, leading to activation of TGF-β1, signaling through its receptor ALK5, and phosphorylation of its intracellular effector Smad3. Infection of endothelial cells was also found to stimulate collagen synthesis through a mechanism dependent on both TGF-β1 and integrin αvβ6. Immunohistochemical analysis showed integrin αvβ6 up-regulation in capillaries proximal to foci of CMV infection in lungs, salivary glands, uterine decidua, and injured chorionic villi of the placenta, demonstrating both its induction in endothelium and up-regulation in epithelium in vivo. Our results suggest that activation of TGF-β1 by integrin αvβ6 contributes to pathological changes and may impair endothelial cell functions in tissues that are chronically infected with CMV. PMID:18349127

  13. Bovine colostrum enhances natural killer cell activity and immune response in a mouse model of influenza infection and mediates intestinal immunity through toll-like receptors 2 and 4.

    PubMed

    Wong, Eric B; Mallet, Jean-François; Duarte, Jairo; Matar, Chantal; Ritz, Barry W

    2014-04-01

    Oral administration of bovine colostrum affects intestinal immunity, including an increased percentage of natural killer (NK) cells. However, effects on NK cell cytotoxic activity and resistance to infection as well as a potential mechanism remain unclear. Therefore, we investigated the effects of bovine colostrum (La Belle, Inc, Bellingham, WA) on the NK cytotoxic response to influenza infection and on toll-like receptor (TLR) activity in a primary intestinal epithelial cell culture. We hypothesized that colostrum would increase NK cell activity and that TLR-2 and TLR-4 blocking would reduce interleukin 6 production by epithelial cells in response to contact stimulation with colostrum. Four-month-old female C57BL/6 mice were supplemented with 1 g of colostrum per kilogram of body weight before and after infection with influenza A virus (H1N1). Animals were assessed for weight loss, splenic NK cell activity, and lung virus titers. Colostrum-supplemented mice demonstrated less reduction in body weight after influenza infection, indicating a less severe infection, increased NK cell cytotoxicity, and less virus burden in the lungs compared with controls. Colostrum supplementation enhanced NK cell cytotoxicity and improved the immune response to primary influenza virus infection in mice. To investigate a potential mechanism, a primary culture of small intestine epithelial cells was then stimulated with colostrum. Direct activation of epithelial cells resulted in increased interleukin 6 production, which was inhibited with TLR-2 and TLR-4 blocking antibodies. The interaction between colostrum and immunity may be dependent, in part, on the interaction of colostrum components with innate receptors at the intestinal epithelium, including TLR-2 and TLR-4. PMID:24774068

  14. Bovine colostrum enhances natural killer cell activity and immune response in a mouse model of influenza infection and mediates intestinal immunity through toll-like receptors 2 and 4.

    PubMed

    Wong, Eric B; Mallet, Jean-François; Duarte, Jairo; Matar, Chantal; Ritz, Barry W

    2014-04-01

    Oral administration of bovine colostrum affects intestinal immunity, including an increased percentage of natural killer (NK) cells. However, effects on NK cell cytotoxic activity and resistance to infection as well as a potential mechanism remain unclear. Therefore, we investigated the effects of bovine colostrum (La Belle, Inc, Bellingham, WA) on the NK cytotoxic response to influenza infection and on toll-like receptor (TLR) activity in a primary intestinal epithelial cell culture. We hypothesized that colostrum would increase NK cell activity and that TLR-2 and TLR-4 blocking would reduce interleukin 6 production by epithelial cells in response to contact stimulation with colostrum. Four-month-old female C57BL/6 mice were supplemented with 1 g of colostrum per kilogram of body weight before and after infection with influenza A virus (H1N1). Animals were assessed for weight loss, splenic NK cell activity, and lung virus titers. Colostrum-supplemented mice demonstrated less reduction in body weight after influenza infection, indicating a less severe infection, increased NK cell cytotoxicity, and less virus burden in the lungs compared with controls. Colostrum supplementation enhanced NK cell cytotoxicity and improved the immune response to primary influenza virus infection in mice. To investigate a potential mechanism, a primary culture of small intestine epithelial cells was then stimulated with colostrum. Direct activation of epithelial cells resulted in increased interleukin 6 production, which was inhibited with TLR-2 and TLR-4 blocking antibodies. The interaction between colostrum and immunity may be dependent, in part, on the interaction of colostrum components with innate receptors at the intestinal epithelium, including TLR-2 and TLR-4.

  15. The Unenlarged Lymph Nodes of HIV-1–infected, Asymptomatic Patients with High CD4 T Cell Counts Are Sites for Virus Replication and CD4 T Cell Proliferation. The Impact of Highly Active Antiretroviral Therapy

    PubMed Central

    Tenner-Racz, Klara; Stellbrink, Hans-Jürgen; van Lunzen, Jan; Schneider, Claus; Jacobs, Jan-Peter; Raschdorff, Birgit; Großschupff, Gudrun; Steinman, Ralph M.; Racz, Paul

    1998-01-01

    The efficacy of triple drug therapy for HIV-1 infection encourages its early use to prevent damage to the immune system. We monitored the effects of such therapy on 12 patients with 14–75-mo histories of minimal disease, i.e., CD4+ counts constantly >500/μl and little or no lymph node enlargement. In this way, we could first determine the extent of viral replication and immunoarchitectural changes in unenlarged nodes early in disease, and second follow the response to triple therapy in plasma and lymphoid tissue in tandem. As is known for lymph nodes with more advanced disease, the germinal centers showed productively infected T cells, i.e., CD4+CD1a−CD68− cells labeling intensely for HIV-1 RNA after in situ hybridization. The unenlarged nodes also showed extensive HIV-1 RNA retention on a well-preserved, follicular dendritic cell (FDC) network, and the follicles were abnormal. There were numerous CD8+ cells, many expressing TIA-1 granule antigen. Also, in contrast to normal follicles, CD4+ T cell proliferation was active, with marked increases in the number of cycling, Ki-67+CD4+CD45R0+ cells. After 28 d and 3 mo of therapy, productively infected T cells decreased dramatically and often were not apparent. The labeling of the FDC network for viral RNA also decreased, but not for gag protein. We conclude that HIV-1 replicates and accumulates in lymphoid organs before damage of the immune system, that at this stage of disease de novo production of T cells occurs in the lymphoid tissue, and that the infection is sensitive to triple drug therapy in both plasma and lymph nodes. PMID:9500797

  16. Suppressor cells in Trypanosoma congolense-infected mice.

    PubMed

    Pearson, T W; Roelants, G E; Lundin, L B; Mayor-Withey, K S

    1979-01-01

    Spleen cells from mice infected with T. congolense strongly suppressed lymphocyte stimulation induced in normal spleen cells by incubation with mitogens or allogeneic cells. Cell dilution studies showed that suppressor activity was extremely strong. Suppressor cell activity was markedly reduced by treatment of spleen cell populations with mitomycin-C and was unaffected by treatment with anti-Thy.1 sera and complement. Removal of cells which bound carbonyl iron or which bound to nylon columns, decreased but did not abolish suppressor activity. PMID:313686

  17. Cytotoxic cells induced after Chlamydia psittaci infection in mice

    SciTech Connect

    Lammert, J.K.

    1982-03-01

    The ability of spleen cells from Chlamydia psittaci-infected mice to lyse C. psittaci-infected and uninfected target cell monolayers was studied. The cytotoxicity assay used was a terminal label method in which the number of adherent target cells surviving the interaction with effector cells was determined by measuring the uptake of (3H)uridine by such cells. It was observed that in the first few days postinfection (3 to 5), spleens contained cells that lysed infected and uninfected targets with equal efficiency. Subsequently, infected targets were killed primarily. The activity of effector spleen cells for infected targets continued, although at a reduced level, beyond 21 days postinfection. Intact effector cells were required since a disruption by sonication resulted in a loss of cytotoxicity. The enhanced killing observed with infected targets was also observed when target cells were sensitized with heat- or UV-inactivated C. psittaci. This study suggests that the induction of cytotoxic cells after C. psittaci infection may contribute to the ability of the host to control multiplication of the microorganism.

  18. Late cytomegalovirus infection after hematopoietic stem cell transplantation: case reports

    PubMed Central

    Pinheiro, Sâmara Grapiuna; de Matos, Sócrates Bezerra; Botura, Mônica Borges; Meyer, Roberto; Lima, Fernanda Washington de Mendonça

    2013-01-01

    Cytomegalovirus is related to high rates of morbidity and mortality after hematopoietic stem cell transplantation. This report highlights the importance of adequate monitoring and management of this infection. We report on two cases of patients with late subclinical cytomegalovirus infection. These patients were monitored for antigenemia by indirect immunofluorescence assay. Active cytomegalovirus infection is most common in the first three months after transplantation however the cases reported herein show the importance of monitoring for active infection after Day +100 post-transplantation. Early detection of active infection enables quick preemptive therapy. In conclusion, we emphasize that patients with risk factors for developing severe or late cytomegalovirus disease should be monitored for more than 100 post-transplant days as late active infection is a reality. PMID:24478611

  19. Discriminating Active Tuberculosis from Latent Tuberculosis Infection by flow cytometric measurement of CD161-expressing T cells

    PubMed Central

    Yang, Qianting; Xu, Qian; Chen, Qi; Li, Jin; Zhang, Mingxia; Cai, Yi; Liu, Haiying; Zhou, Yiping; Deng, Guofang; Deng, Qunyi; Zhou, Boping; Kornfeld, Hardy; Chen, Xinchun

    2015-01-01

    Interferon-gamma Release Assays (IGRAs) significantly increases the possibility for early diagnosis of tuberculosis, but IGRAs alone cannot discriminate active TB from LTBI. Therefore, fast and reliable discrimination of active tuberculosis, especially bacteriology negative tuberculosis, from LTBI is a great necessity. Here we established an assay based on flow cytometric multiparameter assay assessing expression of CD161 along with CD3, CD4, and CD8, whereby a set of indices formulated by the percentages of CD3+CD161+, CD3+CD4+CD161+ and CD3+CD8+CD161+ T cells multiplied with lymphocyte/monocyte ratio were established. Application of the CD3+CD8+CD161+ index to compare a cohort of active tuberculosis with a cohort of LTBI or health control yielded 0.7662 (95% confidence interval [CI] 0.6559–0.8552) or 0.7922 (95%  CI 0.6846–0.8763) for sensitivity and 0.9048 (95%  CI 0.8209–0.9580) or 0.8939 (95% CI 0.8392–0.9349) for specificity when the TB cohort was AFB+; the corresponding results were 0.7481 (95%  CI 0.6648–0.8198) or 0.7557 (95%  CI 0.6730–0.8265) for sensitivity and 0.8571 (95%  CI 0.7637–0.9239) or 0.8603 (95%  CI 0.8008–0.9075) for specificity when the TB cohort was AFB−. Our results reveal that in combination with IGRAs, CD161-based indices provide a novel, fast diagnostic solution addressing the limitation of current tuberculosis diagnostics. PMID:26643453

  20. Discriminating Active Tuberculosis from Latent Tuberculosis Infection by flow cytometric measurement of CD161-expressing T cells.

    PubMed

    Yang, Qianting; Xu, Qian; Chen, Qi; Li, Jin; Zhang, Mingxia; Cai, Yi; Liu, Haiying; Zhou, Yiping; Deng, Guofang; Deng, Qunyi; Zhou, Boping; Kornfeld, Hardy; Chen, Xinchun

    2015-12-08

    Interferon-gamma Release Assays (IGRAs) significantly increases the possibility for early diagnosis of tuberculosis, but IGRAs alone cannot discriminate active TB from LTBI. Therefore, fast and reliable discrimination of active tuberculosis, especially bacteriology negative tuberculosis, from LTBI is a great necessity. Here we established an assay based on flow cytometric multiparameter assay assessing expression of CD161 along with CD3, CD4, and CD8, whereby a set of indices formulated by the percentages of CD3(+)CD161(+), CD3(+)CD4(+)CD161(+) and CD3(+)CD8(+)CD161(+) T cells multiplied with lymphocyte/monocyte ratio were established. Application of the CD3(+)CD8(+)CD161(+) index to compare a cohort of active tuberculosis with a cohort of LTBI or health control yielded 0.7662 (95% confidence interval [CI] 0.6559-0.8552) or 0.7922 (95% CI 0.6846-0.8763) for sensitivity and 0.9048 (95% CI 0.8209-0.9580) or 0.8939 (95% CI 0.8392-0.9349) for specificity when the TB cohort was AFB(+); the corresponding results were 0.7481 (95% CI 0.6648-0.8198) or 0.7557 (95% CI 0.6730-0.8265) for sensitivity and 0.8571 (95% CI 0.7637-0.9239) or 0.8603 (95% CI 0.8008-0.9075) for specificity when the TB cohort was AFB(-). Our results reveal that in combination with IGRAs, CD161-based indices provide a novel, fast diagnostic solution addressing the limitation of current tuberculosis diagnostics.

  1. Therapeutic depletion of natural killer cells controls persistent infection.

    PubMed

    Waggoner, Stephen N; Daniels, Keith A; Welsh, Raymond M

    2014-02-01

    Persistent viral infections are associated with host and viral factors that impair effective antiviral immunity. Natural killer (NK) cells contribute to establishment of persistent lymphocytic choriomeningitis virus (LCMV) infection in mice through suppression of virus-specific T cell responses during the first few days of infection, but NK cell depletion during those early time points can enable severe T cell-mediated immune pathology and death of the host. Here we show that long after their peak in cytolytic activation, NK cells continue to support viral persistence at later times of infection. Delayed depletion of NK cells, 2 to 3 weeks after infection, enhanced virus-specific T cell responses and viral control. This enhancing effect of delayed NK cell depletion on antiviral immunity, in contrast to early NK cell depletion, was not associated with increased morbidity and mortality, and mice quickly regained weight after treatment. The efficacy of the depletion depended in part upon the size of the original virus inoculum, the viral load at the time of depletion, and the presence of CD4 T cells. Each of these factors is an important contributor to the degree of CD8 T cell dysfunction during viral persistence. Thus, NK cells may continuously contribute to exhaustion of virus-specific T cells during chronic infection, possibly by depleting CD4 T cells. Targeting of NK cells could thus be considered in combination with blockade of other immunosuppressive pathways, such as the interleukin-10 (IL-10) and programmed death 1 (PD-1) pathways, as a therapy to cure chronic human infections, including those with HIV or hepatitis C virus. IMPORTANCE Persistent virus infections are a major threat to global human health. The capacity of viruses, including HIV and hepatitis C virus, to overwhelm or subvert host immune responses contributes to a prolonged state of dampened antiviral immune functionality, which in turn facilitates viral persistence. Recent efforts have focused on

  2. Efficacy and Safety of a Preemptive Antiviral Therapy Strategy Based on Combined Virological and Immunological Monitoring for Active Cytomegalovirus Infection in Allogeneic Stem Cell Transplant Recipients

    PubMed Central

    Navarro, David; Amat, Paula; de la Cámara, Rafael; López, Javier; Vázquez, Lourdes; Serrano, David; Nieto, José; Rovira, Monserrat; Piñana, José Luis; Giménez, Estela; Solano, Carlos

    2016-01-01

    Background. Preemptive antiviral therapy for active cytomegalovirus (CMV) infection in allogeneic stem cell transplant recipients (Allo-SCT) results in overtreatment and a high rate of recurrences. Monitoring of CMV-specific T-cell immunity may help to individualize treatments and minimize these problems. Methods. We conducted a prospective, multicenter, matched comparison-group study to evaluate the efficacy and safety of a novel strategy that consisted of interrupting anti-CMV therapy upon CMV DNAemia clearance and concurrent detection of phosphoprotein 65/immediate-early-1-specific interferon-γ-producing CD8+ T cells at levels of >1 cell/µL (within 30 days after the initiation of therapy). Immunological monitoring was performed on days +7, +14, +21, and +28 after treatment initiation. The primary endpoint was the cumulative incidence of recurrent DNAemia within 2 months after treatment cessation. Secondary endpoints were the length of antiviral treatment courses and the incidence of hematological toxicity. Results. Sixty-one patients were enrolled in the study group. Fifty-six patients were included in the matched-control group. Eleven patients (18%) fulfilled the criteria for antiviral treatment interruption. The cumulative incidence of recurrent CMV DNAemia was significantly lower (P = .02) in these patients than in patients in the comparative groups. Likewise, the length of antiviral treatment courses was significantly shorter in these patients than that in patients in the matched-control group (P = .003). No significant differences in the incidence of hematological toxicity was observed between the comparative groups. Conclusions. Our data support the clinical utility of combining immunological and virological monitoring for the management of CMV infection in a subset of Allo-SCT recipients. PMID:27419179

  3. Viral Evasion of Natural Killer Cell Activation

    PubMed Central

    Ma, Yi; Li, Xiaojuan; Kuang, Ersheng

    2016-01-01

    Natural killer (NK) cells play a key role in antiviral innate defenses because of their abilities to kill infected cells and secrete regulatory cytokines. Additionally, NK cells exhibit adaptive memory-like antigen-specific responses, which represent a novel antiviral NK cell defense mechanism. Viruses have evolved various strategies to evade the recognition and destruction by NK cells through the downregulation of the NK cell activating receptors. Here, we review the recent findings on viral evasion of NK cells via the impairment of NK cell-activating receptors and ligands, which provide new insights on the relationship between NK cells and viral actions during persistent viral infections. PMID:27077876

  4. Viral Evasion of Natural Killer Cell Activation.

    PubMed

    Ma, Yi; Li, Xiaojuan; Kuang, Ersheng

    2016-04-12

    Natural killer (NK) cells play a key role in antiviral innate defenses because of their abilities to kill infected cells and secrete regulatory cytokines. Additionally, NK cells exhibit adaptive memory-like antigen-specific responses, which represent a novel antiviral NK cell defense mechanism. Viruses have evolved various strategies to evade the recognition and destruction by NK cells through the downregulation of the NK cell activating receptors. Here, we review the recent findings on viral evasion of NK cells via the impairment of NK cell-activating receptors and ligands, which provide new insights on the relationship between NK cells and viral actions during persistent viral infections.

  5. Identification of a cellular repressor of transcription of the adenoviral late IVa(2) gene that is unaltered in activity in infected cells.

    PubMed

    Lin, H J; Flint, S J

    2000-11-25

    The gene encoding the adenovirus type 2 IVa(2) protein, a sequence-specific activator of transcription from the viral major late promoter, is itself transcribed only during the late phase of infection. We previously identified a cellular protein (IVa(2)-RF) that binds specifically to an intragenic sequence of the IVa(2) transcription unit. We now report that precise substitutions within the IVa(2)-RF-binding site that decreased binding affinity increased the efficiency of IVa(2) transcription in in vitro reactions containing IVa(2)-RF. Consistent with the conclusion that this cellular protein represses IVa(2) transcription, mutations that led to more efficient transcription in the presence of IVa(2)-RF were without effect in reactions lacking this cellular protein. No change in the concentration or activity of IVa(2)-RF could be detected in adenovirus-infected cells during the period in which the IVa(2) gene is transcribed. We therefore propose that restriction of IVa(2) transcription to the late phase is the result of titration of this cellular repressor as the number of copies of the IVa(2) promoter increases upon replication of the viral genome.

  6. Human NK Cell Diversity in Viral Infection: Ramifications of Ramification

    PubMed Central

    Strauss-Albee, Dara M.; Blish, Catherine A.

    2016-01-01

    Natural killer (NK) cells are a unique lymphocyte lineage with remarkable agility in the rapid destruction of virus-infected cells. They are also the most poorly understood class of lymphocyte. A spectrum of activating and inhibitory receptors at the NK cell surface leads to an unusual and difficult-to-study mechanism of cellular recognition, as well as a very high capacity for diversity at the single-cell level. Here, we review the evidence for the role of NK cells in the earliest stage of human viral infection, and in its prevention. We argue that single-cell diversity is a logical evolutionary adaptation for their position in the immune response and contributes to their ability to kill virus-infected cells. Finally, we look to the future, where emerging single-cell technologies will enable a new generation of rigorous and clinically relevant studies on NK cells accounting for all of their unique and diverse characteristics. PMID:26973646

  7. Comparison of the effect of semen from HIV-infected and uninfected men on CD4+ T-cell infection

    PubMed Central

    Camus, Céline; Matusali, Giulia; Bourry, Olivier; Mahe, Dominique; Aubry, Florence; Bujan, Louis; Pasquier, Christophe; Massip, Patrice; Ravel, Célia; Zirafi, Onofrio; Munch, Jan; Roan, Nadia R.; Pineau, Charles; Dejucq-Rainsford, Nathalie

    2016-01-01

    Objectives: Semen composition is influenced by HIV-1 infection, yet the impact of semen components on HIV infection of primary target cells has only been studied in samples from HIV-uninfected donors. Design: We compared the effect of seminal plasma (SP) from chronically HIV-infected (SP+) versus uninfected donors (SP–) on HIV-1 infection of peripheral blood mononuclear cells (PBMCs) and CD4+ T cells. Methods: Primary cells were infected with HIV-1 in the presence of SP+ or SP– and analyzed for infection level, metabolic activity, HIV receptor expression, proliferation and activation. SP+ and SP– were compared for infection-enhancing peptides, cytokines and prostaglandin E2 levels. Results: SP– efficiently enhanced HIV-1 R5 infection of CD4+ T cells, whereas SP+ enhancing activity was significantly reduced. RANTES (CCL5) concentrations were elevated in SP+ relative to SP–, whereas the concentrations of infectivity-enhancing peptides [semen-derived enhancer of viral infection (SEVI), SEM1, SEM2] were similar. CCR5 membrane expression levels were reduced on CD4+ T cells shortly postexposure to SP+ compared with SP– and correlated to R5-tropic HIV-1 infection levels, and CCR5 ligands’ concentrations in semen. SP+ and SP– displayed similar enhancing activity on PBMC infection by X4-tropic HIV-1. Addition/depletion of RANTES (regulated on activation, normal T-cell expressed and secreted) from SPs modulated their effect on PBMC infection by R5-tropic HIV-1. Conclusion: Semen from HIV-infected donors exhibits a significantly reduced enhancing potential on CD4+ T-cell infection by R5-tropic HIV-1 when compared with semen from uninfected donors. Our data indicate that elevated seminal concentrations of RANTES in HIV-infected men can influence the ability of semen to enhance infection. PMID:26854806

  8. Co-infection by human immunodeficiency virus type 1 (HIV-1) and human T cell leukemia virus type 1 (HTLV-1): does immune activation lead to a faster progression to AIDS?

    PubMed Central

    2009-01-01

    Background Recent data have shown that HTLV-1 is prevalent among HIV positive patients in Mozambique, although the impact of HTLV-1 infection on HIV disease progression remains controversial. Our aim was to determine the phenotypic profile of T lymphocytes subsets among Mozambican patients co-infected by HIV and HTLV-1. Methods We enrolled 29 patients co-infected by HTLV-1 and HIV (co-infected), 59 patients mono-infected by HIV (HIV) and 16 healthy controls (HC), respectively. For phenotypic analysis, cells were stained with the following fluorochrome-labeled anti-human monoclonal antibodies CD4-APC, CD8-PerCP, CD25-PE, CD62L-FITC, CD45RA-FITC. CD45RO-PE, CD38-PE; being analysed by four-colour flow cytometry. Results We initially found that CD4+ T cell counts were significantly higher in co-infected, as compared to HIV groups. Moreover, CD4+ T Lymphocytes from co-infected patients presented significantly higher levels of CD45RO and CD25, but lower levels of CD45RA and CD62L, strongly indicating that CD4+ T cells are more activated under HTLV-1 plus HIV co-infection. Conclusion Our data indicate that HTLV-1/HIV co-infected patients progress with higher CD4+ T cell counts and higher levels of activation markers. In this context, it is conceivable that in co-infected individuals, these higher levels of activation may account for a faster progression to AIDS. PMID:20028500

  9. CD4 Depletion in SIV-Infected Macaques Results in Macrophage and Microglia Infection with Rapid Turnover of Infected Cells

    PubMed Central

    Ortiz, Alexandra M.; Ryan, Emily S.; McGary, Colleen S.; Deleage, Claire; McAtee, Brigitte B.; He, Tianyu; Apetrei, Cristian; Easley, Kirk; Pahwa, Savita; Collman, Ronald G.; Derdeyn, Cynthia A.; Davenport, Miles P.; Estes, Jacob D.; Silvestri, Guido; Lackner, Andrew A.; Paiardini, Mirko

    2014-01-01

    In rhesus macaques (RMs), experimental depletion of CD4+ T-cells prior to SIV infection results in higher viremia and emergence of CD4-independent SIV-envelopes. In this study we used the rhesus recombinant anti-CD4 antibody CD4R1 to deplete RM CD4+ T-cells prior to SIVmac251 infection and investigate the sources of the increased viral burden and the lifespan of productively infected cells. CD4-depleted animals showed (i) set-point viral load two-logs higher than controls; (ii) macrophages constituting 80% of all SIV vRNA+ cells in lymph node and mucosal tissues; (iii) substantial expansion of pro-inflammatory monocytes; (iv) aberrant activation and infection of microglial cells; and (v) lifespan of productively infected cells significantly longer in comparison to controls, but markedly shorter than previously estimated for macrophages. The net effect of CD4+ T-cell depletion is an inability to control SIV replication and a shift in the tropism of infected cells to macrophages, microglia, and, potentially, other CD4-low cells which all appear to have a shortened in vivo lifespan. We believe these findings have important implications for HIV eradication studies. PMID:25356757

  10. Physcomitrella patens activates reinforcement of the cell wall, programmed cell death and accumulation of evolutionary conserved defence signals, such as salicylic acid and 12-oxo-phytodienoic acid, but not jasmonic acid, upon Botrytis cinerea infection.

    PubMed

    Ponce De León, Inés; Schmelz, Eric A; Gaggero, Carina; Castro, Alexandra; Álvarez, Alfonso; Montesano, Marcos

    2012-10-01

    The moss Physcomitrella patens is an evolutionarily basal model system suitable for the analysis of plant defence responses activated after pathogen assault. Upon infection with the necrotroph Botrytis cinerea, several defence mechanisms are induced in P. patens, including the fortification of the plant cell wall by the incorporation of phenolic compounds and the induced expression of related genes. Botrytis cinerea infection also activates the accumulation of reactive oxygen species and cell death with hallmarks of programmed cell death in moss tissues. Salicylic acid (SA) levels also increase after fungal infection, and treatment with SA enhances transcript accumulation of the defence gene phenylalanine ammonia-lyase (PAL) in P. patens colonies. The expression levels of the genes involved in 12-oxo-phytodienoic acid (OPDA) synthesis, including lipoxygenase (LOX) and allene oxide synthase (AOS), increase in P. patens gametophytes after pathogen assault, together with a rise in free linolenic acid and OPDA concentrations. However, jasmonic acid (JA) could not be detected in healthy or infected tissues of this plant. Our results suggest that, although conserved defence signals, such as SA and OPDA, are synthesized and are probably involved in the defence response of P. patens against B. cinerea infection, JA production appears to be missing. Interestingly, P. patens responds to OPDA and methyl jasmonate by reducing moss colony growth and rhizoid length, suggesting that jasmonate perception is present in mosses. Thus, P. patens can provide clues with regard to the evolution of different defence pathways in plants, including signalling and perception of OPDA and jasmonates in nonflowering and flowering plants.

  11. Modulation of telomerase activity, bTERT and c-Myc induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin during Bovine Herpesvirus 1 infection in MDBK cells.

    PubMed

    Fiorito, Filomena; Cantiello, Antonietta; Granato, Giovanna Elvira; Marfè, Gabriella; Ciarcia, Roberto; Florio, Salvatore; Pagnini, Ugo; De Martino, Luisa; Iovane, Giuseppe

    2014-02-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) influences infection of kidney cells (MDBK) with Bovine Herpesvirus 1 (BHV-1) through an increase in virus replication and an acceleration of BHV-1-induced apoptosis. Previously our group demonstrated that BHV-1, in the early stages of infection, significantly up-regulates telomerase activity in MDBK cells, while, in the late phases of infection, when BHV-1-induced apoptosis occurred, a down-regulation of telomerase activity was detected. Hence, herein, for the first time, we described the influences of TCDD on telomerase activity during virus infection. In kidney cells (MDBK) infected with BHV-1 and exposed to different doses of TCDD we explored telomerase activity by TRAP assay. Concomitantly, we examined protein levels of both bTERT and c-Myc by Western blot analysis. In all groups, TCDD induced an acceleration in down-regulation of telomerase activity. Particularly, TCDD drastically and significantly decreased telomerase activity when virus-induced apoptosis took place. This result was accompanied from an accelerated down-regulation of bTERT and c-Myc. Finally, in the presence of TCDD, we evidenced a dose-dependent overexpression of aryl hydrocarbon receptor. Hence, our data suggest that TCDD, through a significant acceleration in down-regulation of telomerase activity, bTERT and c-Myc, may contribute to accelerated BHV-1-induced apoptosis.

  12. Key role of regulated upon activation normal T-cell expressed and secreted, nonstructural protein1 and myeloperoxidase in cytokine storm induced by influenza virus PR-8 (A/H1N1) infection in A549 bronchial epithelial cells.

    PubMed

    Phung, Thuy Thi Bich; Sugamata, Ryuichi; Uno, Kazuko; Aratani, Yasuaki; Ozato, Keiko; Kawachi, Shoji; Thanh Nguyen, Liem; Nakayama, Toshinori; Suzuki, Kazuo

    2011-12-01

    Influenza virus infection causes severe respiratory disease such as that due to avian influenza (H5N1). Influenza A viruses proliferate in human epithelial cells, which produce inflammatory cytokines/chemokines as a "cytokine storm" attenuated with the viral nonstructural protein 1 (NS1). Cytokine/chemokine production in A549 epithelial cells infected with influenza A/H1N1 virus (PR-8) or nonstructural protein 1 (NS1) plasmid was examined in vitro. Because tumor necrosis factor-α (TNF-α) and regulated upon activation normal T-cell expressed and secreted (RANTES) are predominantly produced from cells infected with PR-8 virus, the effects of mRNA knockdown of these cytokines were investigated. Small interfering (si)TNF-α down-regulated RANTES expression and secretion of RANTES, interleukin (IL)-8, and monocyte chemotactic protein-1 (MCP-1). In addition, siRANTES suppressed interferon (IFN)-γ expression and secretion of RANTES, IL-8, and MCP-1, suggesting that TNF-α stimulates production of RANTES, IL-8, MCP-1, and IFN-γ, and RANTES also increased IL-8, MCP-1, and IFN-γ. Furthermore, administration of TNF-α promoted increased secretion of RANTES, IL-8, and MCP-1. Administration of RANTES enhanced IL-6, IL-8, and MCP-1 production without PR-8 infection. These results strongly suggest that, as an initial step, TNF-α regulates RANTES production, followed by increase of IL-6, IL-8, and MCP-1 and IFNs concentrations. At a later stage, cells transfected with viral NS1 plasmid showed production of a large amount of IL-8 and MCP-1 in the presence of the H(2)O(2)-myeloperoxidse (MPO) system, suggesting that NS1 of PR-8 may induce a "cytokine storm" from epithelial cells in the presence of an H(2)O(2)-MPO system.

  13. Invariant NKT Cell Response to Dengue Virus Infection in Human

    PubMed Central

    Matangkasombut, Ponpan; Chan-in, Wilawan; Opasawaschai, Anunya; Pongchaikul, Pisut; Tangthawornchaikul, Nattaya; Vasanawathana, Sirijitt; Limpitikul, Wannee; Malasit, Prida; Duangchinda, Thaneeya; Screaton, Gavin; Mongkolsapaya, Juthathip

    2014-01-01

    Background Dengue viral infection is a global health threat without vaccine or specific treatment. The clinical outcome varies from asymptomatic, mild dengue fever (DF) to severe dengue hemorrhagic fever (DHF). While adaptive immune responses were found to be detrimental in the dengue pathogenesis, the roles of earlier innate events remain largely uninvestigated. Invariant natural killer T (iNKT) cells represent innate-like T cells that could dictate subsequent adaptive response but their role in human dengue virus infection is not known. We hypothesized that iNKT cells play a role in human dengue infection. Methods Blood samples from a well-characterized cohort of children with DF, DHF, in comparison to non-dengue febrile illness (OFI) and healthy controls at various time points were studied. iNKT cells activation were analyzed by the expression of CD69 by flow cytometry. Their cytokine production was then analyzed after α-GalCer stimulation. Further, the CD1d expression on monocytes, and CD69 expression on conventional T cells were measured. Results iNKT cells were activated during acute dengue infection. The level of iNKT cell activation associates with the disease severity. Furthermore, these iNKT cells had altered functional response to subsequent ex vivo stimulation with α-GalCer. Moreover, during acute dengue infection, monocytic CD1d expression was also upregulated and conventional T cells also became activated. Conclusion iNKT cells might play an early and critical role in the pathogenesis of severe dengue viral infection in human. Targeting iNKT cells and CD1d serve as a potential therapeutic strategy for severe dengue infection in the future. PMID:24945350

  14. Heat Shock Enhances the Expression of the Human T Cell Leukemia Virus Type-I (HTLV-I) Trans-Activator (Tax) Antigen in Human HTLV-I Infected Primary and Cultured T Cells

    PubMed Central

    Kunihiro, Marie; Fujii, Hideki; Miyagi, Takuya; Takahashi, Yoshiaki; Tanaka, Reiko; Fukushima, Takuya; Ansari, Aftab A.; Tanaka, Yuetsu

    2016-01-01

    The environmental factors that lead to the reactivation of human T cell leukemia virus type-1 (HTLV-I) in latently infected T cells in vivo remain unknown. It has been previously shown that heat shock (HS) is a potent inducer of HTLV-I viral protein expression in long-term cultured cell lines. However, the precise HTLV-I protein(s) and mechanisms by which HS induces its effect remain ill-defined. We initiated these studies by first monitoring the levels of the trans-activator (Tax) protein induced by exposure of the HTLV-I infected cell line to HS. HS treatment at 43 °C for 30 min for 24 h led to marked increases in the level of Tax antigen expression in all HTLV-I-infected T cell lines tested including a number of HTLV-I-naturally infected T cell lines. HS also increased the expression of functional HTLV-I envelope gp46 antigen, as shown by increased syncytium formation activity. Interestingly, the enhancing effect of HS was partially inhibited by the addition of the heat shock protein 70 (HSP70)-inhibitor pifithlin-μ (PFT). In contrast, the HSP 70-inducer zerumbone (ZER) enhanced Tax expression in the absence of HS. These data suggest that HSP 70 is at least partially involved in HS-mediated stimulation of Tax expression. As expected, HS resulted in enhanced expression of the Tax-inducible host antigens, such as CD83 and OX40. Finally, we confirmed that HS enhanced the levels of Tax and gp46 antigen expression in primary human CD4+ T cells isolated from HTLV-I-infected humanized NOD/SCID/γc null (NOG) mice and HTLV-I carriers. In summary, the data presented herein indicate that HS is one of the environmental factors involved in the reactivation of HTLV-I in vivo via enhanced Tax expression, which may favor HTLV-I expansion in vivo. PMID:27409630

  15. Heat Shock Enhances the Expression of the Human T Cell Leukemia Virus Type-I (HTLV-I) Trans-Activator (Tax) Antigen in Human HTLV-I Infected Primary and Cultured T Cells.

    PubMed

    Kunihiro, Marie; Fujii, Hideki; Miyagi, Takuya; Takahashi, Yoshiaki; Tanaka, Reiko; Fukushima, Takuya; Ansari, Aftab A; Tanaka, Yuetsu

    2016-07-11

    The environmental factors that lead to the reactivation of human T cell leukemia virus type-1 (HTLV-I) in latently infected T cells in vivo remain unknown. It has been previously shown that heat shock (HS) is a potent inducer of HTLV-I viral protein expression in long-term cultured cell lines. However, the precise HTLV-I protein(s) and mechanisms by which HS induces its effect remain ill-defined. We initiated these studies by first monitoring the levels of the trans-activator (Tax) protein induced by exposure of the HTLV-I infected cell line to HS. HS treatment at 43 °C for 30 min for 24 h led to marked increases in the level of Tax antigen expression in all HTLV-I-infected T cell lines tested including a number of HTLV-I-naturally infected T cell lines. HS also increased the expression of functional HTLV-I envelope gp46 antigen, as shown by increased syncytium formation activity. Interestingly, the enhancing effect of HS was partially inhibited by the addition of the heat shock protein 70 (HSP70)-inhibitor pifithlin-μ (PFT). In contrast, the HSP 70-inducer zerumbone (ZER) enhanced Tax expression in the absence of HS. These data suggest that HSP 70 is at least partially involved in HS-mediated stimulation of Tax expression. As expected, HS resulted in enhanced expression of the Tax-inducible host antigens, such as CD83 and OX40. Finally, we confirmed that HS enhanced the levels of Tax and gp46 antigen expression in primary human CD4⁺ T cells isolated from HTLV-I-infected humanized NOD/SCID/γc null (NOG) mice and HTLV-I carriers. In summary, the data presented herein indicate that HS is one of the environmental factors involved in the reactivation of HTLV-I in vivo via enhanced Tax expression, which may favor HTLV-I expansion in vivo.

  16. Heat Shock Enhances the Expression of the Human T Cell Leukemia Virus Type-I (HTLV-I) Trans-Activator (Tax) Antigen in Human HTLV-I Infected Primary and Cultured T Cells.

    PubMed

    Kunihiro, Marie; Fujii, Hideki; Miyagi, Takuya; Takahashi, Yoshiaki; Tanaka, Reiko; Fukushima, Takuya; Ansari, Aftab A; Tanaka, Yuetsu

    2016-01-01

    The environmental factors that lead to the reactivation of human T cell leukemia virus type-1 (HTLV-I) in latently infected T cells in vivo remain unknown. It has been previously shown that heat shock (HS) is a potent inducer of HTLV-I viral protein expression in long-term cultured cell lines. However, the precise HTLV-I protein(s) and mechanisms by which HS induces its effect remain ill-defined. We initiated these studies by first monitoring the levels of the trans-activator (Tax) protein induced by exposure of the HTLV-I infected cell line to HS. HS treatment at 43 °C for 30 min for 24 h led to marked increases in the level of Tax antigen expression in all HTLV-I-infected T cell lines tested including a number of HTLV-I-naturally infected T cell lines. HS also increased the expression of functional HTLV-I envelope gp46 antigen, as shown by increased syncytium formation activity. Interestingly, the enhancing effect of HS was partially inhibited by the addition of the heat shock protein 70 (HSP70)-inhibitor pifithlin-μ (PFT). In contrast, the HSP 70-inducer zerumbone (ZER) enhanced Tax expression in the absence of HS. These data suggest that HSP 70 is at least partially involved in HS-mediated stimulation of Tax expression. As expected, HS resulted in enhanced expression of the Tax-inducible host antigens, such as CD83 and OX40. Finally, we confirmed that HS enhanced the levels of Tax and gp46 antigen expression in primary human CD4⁺ T cells isolated from HTLV-I-infected humanized NOD/SCID/γc null (NOG) mice and HTLV-I carriers. In summary, the data presented herein indicate that HS is one of the environmental factors involved in the reactivation of HTLV-I in vivo via enhanced Tax expression, which may favor HTLV-I expansion in vivo. PMID:27409630

  17. Bovine viral diarrhea virus infection induces autophagy in MDBK cells.

    PubMed

    Fu, Qiang; Shi, Huijun; Ren, Yan; Guo, Fei; Ni, Wei; Qiao, Jun; Wang, Pengyan; Zhang, Hui; Chen, Chuangfu

    2014-07-01

    Bovine viral diarrhea virus (BVDV) is an enveloped, positive-sense, single-stranded RNA virus that belongs to the genus Pestivirus (Flaviviridae). The signaling pathways and levels of signaling molecules are altered in Madin-Darby Bovine Kidney (MDBK) cells infected with BVDV. Autophagy is a conservative biological degradation pathway that mainly eliminates and degrades damaged or superfluous organelles and macromolecular complexes for intracellular recycling in eukaryotic cells. Autophagy can also be induced as an effective response to maintain cellular homeostasis in response to different stresses, such as nutrient or growth factor deprivation, hypoxia, reactive oxygen species exposure and pathogen infection. However, the effects of BVDV infection on autophagy in MDBK cells remain unclear. Therefore, we performed an analysis of autophagic activity after BVDV NADL infection using real-time PCR, electron microscopy, laser confocal microscopy, and Western blotting analysis. The results demonstrated that BVDV NADL infection increased autophagic activity and significantly elevated the expression levels of the autophagy-related genes Beclin1 and ATG14 in MDBK cells. However, the knockdown of Beclin1 and ATG14 by RNA interference (RNAi) did not affect BVDV NADL infection-related autophagic activity. These findings provided a novel perspective to elaborate the effects of viral infection on the host cells.

  18. Huntingtons Disease Mice Infected with Toxoplasma gondii Demonstrate Early Kynurenine Pathway Activation, Altered CD8+ T-Cell Responses, and Premature Mortality

    PubMed Central

    Donley, David W.; Olson, Andrew R.; Raisbeck, Merl F.; Fox, Jonathan H.; Gigley, Jason P.

    2016-01-01

    Huntington's disease (HD) is a progressive neurodegenerative disorder caused by a polyglutamine-repeat expansion in the huntingtin protein. Activation of the kynurenine pathway of tryptophan degradation is implicated in the pathogenesis of HD. Indoleamine-2,3-dioxygenase (IDO) catalyzes the oxidation of tryptophan to kynurenine, the first step in this pathway. The prevalent, neuroinvasive protozoal pathogen Toxoplasma gondii (T. gondii) results in clinically silent life-long infection in immune-competent individuals. T. gondii infection results in activation of IDO which provides some protection against the parasite by depleting tryptophan which the parasite cannot synthesize. The kynurenine pathway may therefore represent a point of synergism between HD and T. gondii infection. We show here that IDO activity is elevated at least four-fold in frontal cortex and striata of non-infected N171-82Q HD mice at 14-weeks corresponding to early–advanced HD. T. gondii infection at 5 weeks resulted in elevation of cortical IDO activity in HD mice. HD-infected mice died significantly earlier than wild-type infected and HD control mice. Prior to death, infected HD mice demonstrated decreased CD8+ T-lymphocyte proliferation in brain and spleen compared to wild-type infected mice. We demonstrate for the first time that HD mice have an altered response to an infectious agent that is characterized by premature mortality, altered immune responses and early activation of IDO. Findings are relevant to understanding how T. gondii infection may interact with pathways mediating neurodegeneration in HD. PMID:27611938

  19. Huntingtons Disease Mice Infected with Toxoplasma gondii Demonstrate Early Kynurenine Pathway Activation, Altered CD8+ T-Cell Responses, and Premature Mortality.

    PubMed

    Donley, David W; Olson, Andrew R; Raisbeck, Merl F; Fox, Jonathan H; Gigley, Jason P

    2016-01-01

    Huntington's disease (HD) is a progressive neurodegenerative disorder caused by a polyglutamine-repeat expansion in the huntingtin protein. Activation of the kynurenine pathway of tryptophan degradation is implicated in the pathogenesis of HD. Indoleamine-2,3-dioxygenase (IDO) catalyzes the oxidation of tryptophan to kynurenine, the first step in this pathway. The prevalent, neuroinvasive protozoal pathogen Toxoplasma gondii (T. gondii) results in clinically silent life-long infection in immune-competent individuals. T. gondii infection results in activation of IDO which provides some protection against the parasite by depleting tryptophan which the parasite cannot synthesize. The kynurenine pathway may therefore represent a point of synergism between HD and T. gondii infection. We show here that IDO activity is elevated at least four-fold in frontal cortex and striata of non-infected N171-82Q HD mice at 14-weeks corresponding to early-advanced HD. T. gondii infection at 5 weeks resulted in elevation of cortical IDO activity in HD mice. HD-infected mice died significantly earlier than wild-type infected and HD control mice. Prior to death, infected HD mice demonstrated decreased CD8+ T-lymphocyte proliferation in brain and spleen compared to wild-type infected mice. We demonstrate for the first time that HD mice have an altered response to an infectious agent that is characterized by premature mortality, altered immune responses and early activation of IDO. Findings are relevant to understanding how T. gondii infection may interact with pathways mediating neurodegeneration in HD. PMID:27611938

  20. Apoptotic activity and anti-Toxoplasma effects of artemether on the tachyzoites and experimental infected Vero and J774 cell lines by Toxoplasma gondii

    PubMed Central

    Mikaeiloo, Hajar; Ghaffarifar, Fatemeh; Dalimi, Abdolhossein; Sharifi, Zohreh; Hassan, Zuhair Mohammad

    2016-01-01

    Objectives: Drugs used for toxoplasmosis have limited efficacy and also severe side effects. A new drug with good efficacy and limited side effects is need of the hour. We studied the effects of artemether on Toxoplasma gondii in vitro conditions. Materials and Methods: Artemether (methyl-ether-qinghaosu) was tested for tachyzoites, J774, and Vero cell lines infected by T. gondii. For evaluating the effect of drugs on Vero cells infected with T. gondii, we designed two separate experiments; in the first experiment, the Vero cells were infected with tachyzoites and then treated with artemether; while in the second one, the tachyzoites were exposed to artemether and then Vero cells were infected with treated tachyzoites. For evaluating the apoptotic effect of artemether on tachyzoites and infected J774 macrophages cell line with T. gondii, we used flow cytometry method. Inhibitory concentration (IC50) was evaluated by intracellular replication of tachyzoites in Vero cells. Results: IC50 for infected Vero cells with tachyzoites was determined as 49.13 μg/ml. In pretreated tachyzoites with artemether before entering into Vero cells, IC50 was calculated as 13.15 μg/ml. In both experiments, artemether showed a higher inhibitory effect than sulfadiazine (positive control). Artemether even at the highest concentrations only showed low cytotoxicity on Vero and J774 cell lines. Apoptosis in tachyzoites rise with an increasing concentration of artemether. Conclusions: Our findings indicate that artemether is effective to control the tachyzoites of T. gondii in vitro and maybe a good alternative drug for toxoplasmosis. PMID:27127321

  1. Effect of parasitic infection on dopamine biosynthesis in dopaminergic cells

    PubMed Central

    Martin, H.L.; Alsaady, I.; Howell, G.; Prandovszky, E.; Peers, C.; Robinson, P.; McConkey, G.A.

    2015-01-01

    Infection by the neurotropic agent Toxoplasma gondii alters rodent behavior and can result in neuropsychiatric symptoms in humans. Little is understood regarding the effects of infection on host neural processes but alterations to dopaminergic neurotransmission are implicated. We have previously reported elevated levels of dopamine (DA) in infected dopaminergic cells however the involvement of the host enzymes and fate of the produced DA were not defined. In order to clarify the effects of infection on host DA biosynthetic enzymes and DA packaging we examined enzyme levels and activity and DA accumulation and release in T. gondii-infected neurosecretory cells. Although the levels of the host tyrosine hydroxylase (TH) and DOPA decarboxylase and AADC (DDC) did not change significantly in infected cultures, DDC was found within the parasitophorous vacuole (PV), the vacuolar compartment where the parasites reside, as well as in the host cytosol in infected dopaminergic cells. Strikingly, DDC was found within the intracellular parasite cysts in infected brain tissue. This finding could provide some explanation for observations of DA within tissue cysts in infected brain as a parasite-encoded enzyme with TH activity was also localized within tissue cysts. In contrast, cellular DA packaging appeared unchanged in single-cell microamperometry experiments and only a fraction of the increased DA was accessible to high potassium-induced release. This study provides some understanding of how this parasite produces elevated DA within dopaminergic cells without the toxic ramifications of free cytosolic DA. The mechanism for synthesis and packaging of DA by T. gondii-infected dopaminergic cells may have important implications for the effects of chronic T. gondii infection on humans and animals. PMID:26297895

  2. Novel Inhaled Combination Powder Containing Amorphous Colistin and Crystalline Rifapentine with Enhanced Antimicrobial Activities against Planktonic Cells and Biofilm of Pseudomonas aeruginosa for Respiratory Infections.

    PubMed

    Zhou, Qi Tony; Sun, Si-Ping; Chan, John Gar Yan; Wang, Ping; Barraud, Nicolas; Rice, Scott A; Wang, Jiping; Li, Jian; Chan, Hak-Kim

    2015-08-01

    Colistin has been increasingly used for the treatment of respiratory infections caused by Gram-negative bacteria. Unfortunately parenteral administration of colistin can cause severe adverse effects. This study aimed to develop an inhaled combination dry powder formulation of colistin and rifapentine for the treatment of respiratory infections. The combination formulation was produced by spray-drying rifapentine particles suspended in an aqueous colistin solution. The combination dry powder had enhanced antimicrobial activities against planktonic cells and biofilm cultures of Pseudomonas aeruginosa, with both minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC) values (2 and 4 mg/L, respectively) being half that of pure colistin (MIC 4 mg/L and MBIC 8 mg/L) and 1/16th that of pure rifapentine (MIC 32 mg/L and MBIC 64 mg/L). High aerosol performance, as measured via an Aerolizer device, was observed with emitted doses>89% and fine particle fraction (FPF) total>76%. The proportion of submicron particles of rifapentine particles was minimized by the attachment of colistin, which increased the overall particle mass and aerodynamic size distribution. Using the spray-drying method described here, stable particles of amorphous colistin and crystalline rifapentine were distributed homogeneously in each stage of the impinger. Unlike the colistin alone formulation, no deterioration in aerosol performance was found for the combination powder when exposed to a high relative humidity of 75%. In our previous study, surface coating by rifampicin contributed to the moisture protection of colistin. Here, a novel approach with a new mechanism was proposed whereby moisture protection was attributed to the carrier effect of elongated crystalline rifapentine particles, which minimized contact between hygroscopic colistin particles. This inhaled combination antibiotic formulation with enhanced aerosol dispersion efficiency and in vitro efficacy

  3. The viral non-structural protein 1 alpha (Nsp1α) inhibits p53 apoptosis activity by increasing murine double minute 2 (mdm2) expression in porcine reproductive and respiratory syndrome virus (PRRSV) early-infected cells.

    PubMed

    Wang, Xiaodu; Shao, Chunyan; Wang, Luyan; Li, Qunjing; Song, Houhui; Fang, Weihuan

    2016-02-29

    Apoptosis is one of the most important mechanisms of pathogenesis in porcine reproductive and respiratory syndrome virus (PRRSV)-infected cells. The tumor suppressor p53 plays a critical role in apoptotic induction in viral infections. In the present study, we found that p53 activity was inhibited at the early stage of PRRSV infection in both the highly pathogenic (HP) and lowly pathogenic (LP) PRRSV isolates. Bax expression showed a similar change pattern to that of p53. Murine double minute 2 (mdm2) expressed higher in PRRSV-infected cells than in uninfected cells at the early stage of infection and promoted p53 degradation. We show for the first time that the non-structural protein 1 alpha (Nsp1α) of PRRSV is a negative regulator of p53 activity through increasing mdm2 expression and p53 ubiquitination, while p53 is inhibitory to PRRSV replication at the early stage of infection. We conclude that PRRSV manipulates the host factors mdm2 and p53 via its Nsp1α for increased replication at the early stage of infection. These provide a novel perspective to understand the interaction between apoptosis and replication of PRRSV.

  4. NK Cells and Their Ability to Modulate T Cells during Virus Infections

    PubMed Central

    Cook, Kevin D.; Waggoner, Stephen N.; Whitmire, Jason K.

    2014-01-01

    Natural killer (NK) cells are important in protection against virus infections, and many viruses have evolved mechanisms to thwart NK cell activity. NK cells respond to inflammatory signals at an early stage of virus infection, resulting in proliferation, cytokine production, and cytolytic activity that can reduce virus loads. Moreover, the rapid kinetics of the NK cell response enables NK cells to influence other populations of innate immune cells, affect the inflammatory milieu, and guide adaptive immune responses to infection. Early NK cell interactions with other leukocytes can have long-lasting effects on the number and quality of memory T cells, as well as impact the exhaustion of T cells during chronic infections. The ability of NK cells to modulate T cell responses can be mediated through direct T-NK interactions, cytokine production, or indirectly through dendritic cells and other cell types. Herein, we summarize our current understanding of how NK cells interact with T cells, dendritic cells, B cells, and other cell types involved in adaptive immune responses to virus infection. We outline several mechanisms by which NK cells enhance or suppress adaptive immune response and long-lived immunological memory. PMID:25404045

  5. Infection of human THP-1 cells with dormant Mycobacterium tuberculosis.

    PubMed

    Iona, Elisabetta; Pardini, Manuela; Gagliardi, Maria Cristina; Colone, Marisa; Stringaro, Anna Rita; Teloni, Raffaela; Brunori, Lara; Nisini, Roberto; Fattorini, Lanfranco; Giannoni, Federico

    2012-09-01

    Dormant, non-replicating Mycobacterium tuberculosis H37Rv strain cultured in hypoxic conditions was used to infect THP-1 cells. CFUs counting, Kinyoun staining and electron microscopy showed that dormant bacilli infected THP-1 cells at a rate similar to replicating M. tuberculosis, but failed to grow during the first 6 days of infection. The absence of growth was specific to the intracellular compartment, as demonstrated by efficient growth in liquid medium. Quantification of β-actin mRNA recovered from infected cells showed that, in contrast with log-phase bacteria, infection with dormant bacilli determined a reduced THP-1 cell death. Gene expression of intracellular non-replicating bacteria showed a pattern typical of a dormant state. Intracellular dormant bacteria induced the activation of genes associated to a proinflammatory response in THP-1 cells. Though, higher levels of TNFα, IL-1β and IL-8 mRNAs compared to aerobic H37Rv infected cells were not paralleled by increased cytokine accumulation in the supernatants. Moreover, dormant bacilli induced a higher expression of inducible cox-2 gene, accompanied by increased PGE2 secretion. Overall, our data describe a new model of in vitro infection using dormant M. tuberculosis that could provide the basis for understanding how non-replicating bacilli survive intracellularly and influence the maintenance of the hypoxic granuloma.

  6. HIV Infection of Monocytes-Derived Dendritic Cells Inhibits Vγ9Vδ2 T Cells Functions

    PubMed Central

    Sacchi, Alessandra; Rinaldi, Alessandra; Tumino, Nicola; Casetti, Rita; Agrati, Chiara; Turchi, Federica; Bordoni, Veronica; Cimini, Eleonora; Martini, Federico

    2014-01-01

    DCs act as sentinel cells against incoming pathogens and represent the most potent antigen presenting cells, having the unique capability to prime naïve T cells. In addition to their role in induction of adaptive immune responses, DC are also able to activate innate cells as γδ T cells; in particular, a reciprocal crosstalk between DC and γδ T cells was demonstrated. However, whether HIV infection may alter DC-Vγ9Vδ2 T cells cross-talk was not yet described. To clarify this issue, we cultured activated Vγ9Vδ2 T cells with HIV infected monocyte derived DC (MoDC). After 5 days we evaluated MoDC phenotype, and Vγ9Vδ2 T cells activation and proliferation. In our model, Vγ9Vδ2 T cells were not able to proliferate in response to HIV-infected MoDC, although an up-regulation of CD69 was observed. Upon phosphoantigens stimulation, Vγ9Vδ2 T cells proliferation and cytokine production were inhibited when cultured with HIV-infected MoDC in a cell-contact dependent way. Moreover, HIV-infected MoDC are not able to up-regulate CD86 molecules when cultured with activated Vγ9Vδ2 T cells, compared with uninfected MoDC. Further, activated Vγ9Vδ2 T cells are not able to induce HLA DR up-regulation and CCR5 down-regulation on HIV-infected MoDC. These data indicate that HIV-infected DC alter the capacity of Vγ9Vδ2 T cells to respond to their antigens, pointing out a new mechanisms of induction of Vγ9Vδ2 T cells anergy carried out by HIV, that could contribute to immune evasion. PMID:25340508

  7. Type 1 IFN-independent activation of a subset of interferon stimulated genes in West Nile virus Eg101-infected mouse cells

    SciTech Connect

    Pulit-Penaloza, Joanna A.; Scherbik, Svetlana V.; Brinton, Margo A.

    2012-04-10

    Although infection of mouse embryofibroblasts (MEFs) with WNV Eg101 induced interferon (IFN) beta production and STAT1 and STAT2 phosphorylation, these transcription factors (TFs) were not detected in the nucleus or on the promoters of four IRF-3-independent interferon stimulated genes (ISGs): Oas1a and Irf7 (previously characterized as IFN/ISGF3-dependent), Oas1b and Irf1. These ISGs were upregulated in WNV Eg101-infected STAT1-/-, STAT2-/-, and IFN alpha/beta receptor -/- MEFs. Although either IRF-3 or IRF-7 could amplify/sustain Oas1a and Oas1b upregulation at later times after infection, these factors were not required for the initial gene activation. The lack of upregulation of these ISGs in WNV Eg101-infected IRF-3/9-/- MEFs suggested the involvement of IRF-9. Activation of Irf1 in infected MEFs did not depend on any of these IRFs. The data indicate that additional alternative activation mechanisms exist for subsets of ISGs when a virus infection has blocked ISG activation by the canonical IFN-mediated pathway.

  8. T cell responses to DosR and Rpf proteins in actively and latently infected individuals from Colombia.

    PubMed

    Riaño, Felipe; Arroyo, Leonar; París, Sara; Rojas, Mauricio; Friggen, Annemieke H; van Meijgaarden, Krista E; Franken, Kees L M C; Ottenhoff, Tom H M; García, Luis F; Barrera, Luis F

    2012-03-01

    Mycobacterium tuberculosis DosR regulon-encoded proteins elicit strong immune T-cell responses in individuals with latent tuberculosis (LTBI). Also, resuscitation (Rpf) proteins can induce such responses. However, variations in the immunogenicity of the DosR and Rpf proteins have been observed in European and African populations, and no data are published from other geographic areas. In Colombian LTBI and patients with recently diagnosed PTB, we therefore studied the immune response to DosR, Rpf, stress, and nominal antigens from Mtb, in 7-day stimulated cultures. Three DosR (Rv1737c, Rv2029c, Rv2628c) and 2 Rpf (Rv0867 and Rv2389c) antigens were recognized most prominently on the basis of the net IFNγ production (DosR) or the percentage of responding individuals (Rpf). Results show that the selected DosR antigens induced a higher proportion of CD4-T cells producing IFNγ from LTBI, compared to pulmonary TB patients (PTB), while there were no differences in the proportion of CD8-T cells. An increased frequency of CD4, but not CD8 T-cells with a CD45RO(+)CD27(+) phenotype was observed in LTBI in response to Rv2029c, Rv0867c, and Rv2389c, compared to PTB. The levels of cytokines and chemokines in the supernatants of stimulated cells, showed that the DosR and Rpf antigens induced higher levels of IFNγ in cultures from LTBI compared to PTB, although the induced pattern of cytokines and chemokines was also antigen dependent. In summary, our results are consistent with the significant immunogenicity of Mtb DosR and Rpf antigens in LTBI individuals, and confirm and extend previously reported data from other TB affected human populations.

  9. Invariant NKT cells: regulation and function during viral infection.

    PubMed

    Juno, Jennifer A; Keynan, Yoav; Fowke, Keith R

    2012-01-01

    Natural killer T cells (NKT cells) represent a subset of T lymphocytes that express natural killer (NK) cell surface markers. A subset of NKT cells, termed invariant NKT cells (iNKT), express a highly restricted T cell receptor (TCR) and respond to CD1d-restricted lipid ligands. iNKT cells are now appreciated to play an important role in linking innate and adaptive immune responses and have been implicated in infectious disease, allergy, asthma, autoimmunity, and tumor surveillance. Advances in iNKT identification and purification have allowed for the detailed study of iNKT activity in both humans and mice during a variety of chronic and acute infections. Comparison of iNKT function between non-pathogenic simian immunodeficiency virus (SIV) infection models and chronic HIV-infected patients implies a role for iNKT activity in controlling immune activation. In vitro studies of influenza infection have revealed novel effector functions of iNKT cells including IL-22 production and modulation of myeloid-derived suppressor cells, but ex vivo characterization of human iNKT cells during influenza infection are lacking. Similarly, as recent evidence suggests iNKT involvement in dengue virus pathogenesis, iNKT cells may modulate responses to a number of emerging pathogens. This Review will summarize current knowledge of iNKT involvement in responses to viral infections in both human and mouse models and will identify critical gaps in knowledge and opportunities for future study. We will also highlight recent efforts to harness iNKT ligands as vaccine adjuvants capable of improving vaccination-induced cellular immune responses.

  10. Invariant NKT cells: regulation and function during viral infection.

    PubMed

    Juno, Jennifer A; Keynan, Yoav; Fowke, Keith R

    2012-01-01

    Natural killer T cells (NKT cells) represent a subset of T lymphocytes that express natural killer (NK) cell surface markers. A subset of NKT cells, termed invariant NKT cells (iNKT), express a highly restricted T cell receptor (TCR) and respond to CD1d-restricted lipid ligands. iNKT cells are now appreciated to play an important role in linking innate and adaptive immune responses and have been implicated in infectious disease, allergy, asthma, autoimmunity, and tumor surveillance. Advances in iNKT identification and purification have allowed for the detailed study of iNKT activity in both humans and mice during a variety of chronic and acute infections. Comparison of iNKT function between non-pathogenic simian immunodeficiency virus (SIV) infection models and chronic HIV-infected patients implies a role for iNKT activity in controlling immune activation. In vitro studies of influenza infection have revealed novel effector functions of iNKT cells including IL-22 production and modulation of myeloid-derived suppressor cells, but ex vivo characterization of human iNKT cells during influenza infection are lacking. Similarly, as recent evidence suggests iNKT involvement in dengue virus pathogenesis, iNKT cells may modulate responses to a number of emerging pathogens. This Review will summarize current knowledge of iNKT involvement in responses to viral infections in both human and mouse models and will identify critical gaps in knowledge and opportunities for future study. We will also highlight recent efforts to harness iNKT ligands as vaccine adjuvants capable of improving vaccination-induced cellular immune responses. PMID:22916008

  11. Mucosal SIV Vaccines Comprising Inactivated Virus Particles and Bacterial Adjuvants Induce CD8+ T-Regulatory Cells that Suppress SIV-Positive CD4+ T-Cell Activation and Prevent SIV Infection in the Macaque Model

    PubMed Central

    Andrieu, Jean-Marie; Chen, Song; Lai, Chunhui; Guo, Weizhong; Lu, Wei

    2014-01-01

    A new paradigm of mucosal vaccination against human immunodeficiency virus (HIV) infection has been investigated in the macaque model. A vaccine consisting of inactivated simian immunodeficiency virus (SIV)mac239 particles together with a living bacterial adjuvant (either the Calmette and Guerin bacillus, Lactobacillus plantarum or Lactobacillus rhamnosus) was administered to macaques via the vaginal or oral/intragastric route. In contrast to all established human and veterinary vaccines, these three vaccine regimens did not elicit SIV-specific antibodies nor cytotoxic T-lymphocytes but induced a previously unrecognized population of non-cytolytic MHCIb/E-restricted CD8+ T-regulatory cells that suppressed the activation of SIV-positive CD4+ T-lymphocytes. SIV reverse transcription was thereby blocked in inactivated CD4+ T-cells; the initial burst of virus replication was prevented and the vaccinated macaques were protected from a challenge infection. For 3–14 months after intragastric immunization, 24 macaques were challenged intrarectally with a high dose of SIVmac239 or with the heterologous strain SIV B670 (both strains grown on macaques PBMC). Twenty-three of these animals were found to be protected for up to 48 months while all 24 control macaques became infected. This protective effect against SIV challenge together with the concomitant identification of a robust ex vivo correlate of protection suggests a new approach for developing an HIV vaccine in humans. The induction of this new class of CD8+ T-regulatory cells could also possibly be used therapeutically for suppressing HIV replication in infected patients and this novel tolerogenic vaccine paradigm may have potential applications for treating a wide range of immune disorders and is likely to may have profound implications across immunology generally. PMID:25071760

  12. Molecular characteristics of diffuse large B-cell lymphoma in human immunodeficiency virus-infected and -uninfected patients in the pre-highly active antiretroviral therapy and pre-rituximab era.

    PubMed

    Morton, Lindsay M; Kim, Clara J; Weiss, Lawrence M; Bhatia, Kishor; Cockburn, Myles; Hawes, Debra; Wang, Sophia S; Chang, Cindy; Altekruse, Sean F; Engels, Eric A; Cozen, Wendy

    2014-03-01

    Human immunodeficiency virus (HIV) infection substantially elevates diffuse large B-cell lymphoma (DLBCL) risk, but its impact on the distinct DLBCL subtypes defined by cell of origin is unclear. We compared DLBCL molecular characteristics and prognosis in 51 HIV-infected and 116 HIV-uninfected cases diagnosed during 1977-2003. Using immunohistochemistry to classify cell of origin based on the Tally algorithm, activated B-cell (ABC)-DLBCL was substantially more common in HIV-infected (83%) than in HIV-uninfected (54%) cases (p < 0.001). Epstein-Barr virus (EBV) was detected in 63% of DLBCLs in HIV-infected cases, occurring almost exclusively in ABC-DLBCL (74% vs. 13% of germinal center B-cell [GCB]-DLBCL, p = 0.002), but was rarely detected in DLBCLs among HIV-uninfected cases (3%). Among HIV-uninfected cases, MYC/IgH [t(8;14)(q24;q32)] and IgH/BCL2 [t(14;18)(q32;q21)] translocations were significantly more common and BCL6/IgH [t(3;14)(q27;q32)] significantly less common in GCB-DLBCL than in ABC-DLBCL (p = 0.010, < 0.001 and = 0.039, respectively). Among HIV-infected cases, translocations other than MYC/IgH [t(8;14)(q24;q32)] (21%) were rare (≤ 6%) and unrelated to cell of origin. ABC-DLBCL was associated with adverse overall survival compared with GCB-DLBCL regardless of HIV status (pHIV-infected = 0.066; pHIV-uninfected = 0.038). Our data demonstrate key differences in the molecular characteristics, cell of origin and prognosis of DLBCL by HIV status in the pre-highly active antiretroviral therapy (HAART) and pre-rituximab era, supporting biologic differences in lymphomagenesis in the presence of HIV. PMID:23772639

  13. High yield expression of biologically active recombinant full length human tuftelin protein in baculovirus-infected insect cells.

    PubMed

    Shay, B; Gruenbaum-Cohen, Y; Tucker, A S; Taylor, A L; Rosenfeld, E; Haze, A; Dafni, L; Leiser, Y; Fermon, E; Danieli, T; Blumenfeld, A; Deutsch, D

    2009-11-01

    Tuftelin is an acidic protein expressed at very early stages of mouse odontogenesis. It was suggested to play a role during epithelial-mesenchymal interactions, and later, when enamel formation commences, to be involved in enamel mineralization. Tuftelin was also detected in several normal soft tissues of different origins and some of their corresponding cancerous tissues. Tuftelin is expressed in low quantities, and undergoes degradation in the enamel extracellular matrix. To investigate the structure and function of tuftelin, the full length recombinant human tuftelin protein was produced. The full length human tuftelin cDNA was cloned using Gateway recombination into the Bac-to-Bac system compatible transfer vector pDest10. This vector adds a hexahistidine tag to the N-terminus of the expressed protein, enabling one-step affinity purification on nickel column. The recombinant human tuftelin protein was transposed into the bacmid and expressed in Spodoptera frugiperda (Sf9) insect cells. The yield of the purified, his-tagged recombinant full length human Tuftelin (rHTuft+) was 5-8 mg/L culture. rHTuft+ was characterized by SDS-PAGE, Western blot, ESI-TOF spectrometry, restriction mapping and MS/MS sequencing. The availability of the purified, full length recombinant human tuftelin protein opened up the possibility to investigate novel functions of tuftelin. Application of rHTuft+ agarose beads onto embryonic mouse mandibular explants caused changes in the surrounding epithelial cells, including morphology, orientation and spatial organization. Further studies using DiI labeling, revealed that rHTuft+, placed on the tooth germ region, brought about recruitment of adjacent embryonic mesenchymal cells. These findings support the hypothesis that tuftelin plays an important role during embryogenesis.

  14. Fungal Cell Gigantism during Mammalian Infection

    PubMed Central

    Zaragoza, Oscar; García-Rodas, Rocío; Nosanchuk, Joshua D.; Cuenca-Estrella, Manuel; Rodríguez-Tudela, Juan Luis; Casadevall, Arturo

    2010-01-01

    The interaction between fungal pathogens with the host frequently results in morphological changes, such as hyphae formation. The encapsulated pathogenic fungus Cryptococcus neoformans is not considered a dimorphic fungus, and is predominantly found in host tissues as round yeast cells. However, there is a specific morphological change associated with cryptococcal infection that involves an increase in capsule volume. We now report another morphological change whereby gigantic cells are formed in tissue. The paper reports the phenotypic characterization of giant cells isolated from infected mice and the cellular changes associated with giant cell formation. C. neoformans infection in mice resulted in the appearance of giant cells with cell bodies up to 30 µm in diameter and capsules resistant to stripping with γ-radiation and organic solvents. The proportion of giant cells ranged from 10 to 80% of the total lung fungal burden, depending on infection time, individual mice, and correlated with the type of immune response. When placed on agar, giant cells budded to produce small daughter cells that traversed the capsule of the mother cell at the speed of 20–50 m/h. Giant cells with dimensions that approximated those in vivo were observed in vitro after prolonged culture in minimal media, and were the oldest in the culture, suggesting that giant cell formation is an aging-dependent phenomenon. Giant cells recovered from mice displayed polyploidy, suggesting a mechanism by which gigantism results from cell cycle progression without cell fission. Giant cell formation was dependent on cAMP, but not on Ras1. Real-time imaging showed that giant cells were engaged, but not engulfed by phagocytic cells. We describe a remarkable new strategy for C. neoformans to evade the immune response by enlarging cell size, and suggest that gigantism results from replication without fission, a phenomenon that may also occur with other fungal pathogens. PMID:20585557

  15. Fungal cell gigantism during mammalian infection.

    PubMed

    Zaragoza, Oscar; García-Rodas, Rocío; Nosanchuk, Joshua D; Cuenca-Estrella, Manuel; Rodríguez-Tudela, Juan Luis; Casadevall, Arturo

    2010-01-01

    The interaction between fungal pathogens with the host frequently results in morphological changes, such as hyphae formation. The encapsulated pathogenic fungus Cryptococcus neoformans is not considered a dimorphic fungus, and is predominantly found in host tissues as round yeast cells. However, there is a specific morphological change associated with cryptococcal infection that involves an increase in capsule volume. We now report another morphological change whereby gigantic cells are formed in tissue. The paper reports the phenotypic characterization of giant cells isolated from infected mice and the cellular changes associated with giant cell formation. C. neoformans infection in mice resulted in the appearance of giant cells with cell bodies up to 30 microm in diameter and capsules resistant to stripping with gamma-radiation and organic solvents. The proportion of giant cells ranged from 10 to 80% of the total lung fungal burden, depending on infection time, individual mice, and correlated with the type of immune response. When placed on agar, giant cells budded to produce small daughter cells that traversed the capsule of the mother cell at the speed of 20-50 m/h. Giant cells with dimensions that approximated those in vivo were observed in vitro after prolonged culture in minimal media, and were the oldest in the culture, suggesting that giant cell formation is an aging-dependent phenomenon. Giant cells recovered from mice displayed polyploidy, suggesting a mechanism by which gigantism results from cell cycle progression without cell fission. Giant cell formation was dependent on cAMP, but not on Ras1. Real-time imaging showed that giant cells were engaged, but not engulfed by phagocytic cells. We describe a remarkable new strategy for C. neoformans to evade the immune response by enlarging cell size, and suggest that gigantism results from replication without fission, a phenomenon that may also occur with other fungal pathogens.

  16. In vivo activation of the intracrine vitamin D pathway in innate immune cells and mammary tissue during a bacterial infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The active vitamin D metabolite, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), is an important regulator of immune function. The enzyme that synthesizes 1,25(OH)2D3 from 25-hydroxyvitamin D3 is 1alpha-hydroxylase (1alpha-OHase; CYP27B1). Several in vitro studies have shown that TLR signaling induces expre...

  17. Dengue Virus Infection Causes the Activation of Distinct NF-κB Pathways for Inducible Nitric Oxide Synthase and TNF-α Expression in RAW264.7 Cells.

    PubMed

    Cheng, Yi-Lin; Lin, Yee-Shin; Chen, Chia-Ling; Wan, Shu-Wen; Ou, Yi-Dan; Yu, Chia-Yi; Tsai, Tsung-Ting; Tseng, Po-Chun; Lin, Chiou-Feng

    2015-01-01

    Infection with dengue virus (DENV) causes an increase in proinflammatory responses, such as nitric oxide (NO) generation and TNF-α expression; however, the molecular mechanism underlying this inflammatory activation remains undefined, although the activation of the transcription factor NF-κB is generally involved. In addition to TNF-α production in DENV-infected murine macrophage RAW264.7 cells, inducible NO synthase was transcriptionally and posttranslationally elevated and accompanied by NO generation. NF-κB is known to be activated by DENV infection. Pharmacologically inhibiting NF-κB activation abolishes iNOS/NO biosynthesis and TNF-α production. With inhibition, the potential role of NF-κB in oxidative signaling regulation was prevented during DENV infection. Heat-inactivated DENV failed to cause the identified inflammatory responses. Pharmacological inhibition of TLR3 partly decreased NF-κB activation; however, it effectively abolished inducible iNOS/NO biosynthesis but did not inhibit TNF-α production. In contrast to TLR3, viral protein NS2B3 also independently contributed to NF-κB activation to regulate TNF-α production. These results show the distinct pathways for NF-κB activation caused by DENV infection individually for the regulation of iNOS/NO and TNF-α expression. PMID:26199460

  18. HIV-1 infection, microenvironment and endothelial cell dysfunction.

    PubMed

    Mazzuca, Pietro; Caruso, Arnaldo; Caccuri, Francesca

    2016-09-01

    HIV-1 promotes a generalized immune activation that involves the main targets of HIV-1 infection but also cells that are not sensitive to viral infection. ECs display major dysfunctions in HIV+ patients during long-standing viral infection that persist even in the current cART era, in which new-generation drugs have reduced dysmetabolic side effects and successfully impeded viral replication. In vivo studies have failed to demonstrate the presence of replicating virus in ECs suggesting that a direct role of the virus is unlikely, and implying that the mechanism accounting for vascular dysfunction may rely on the indirect action of molecules released in the microenvironment by HIV-1-infected cells. This article reviews the current understanding of how HIV-1 infection can contribute to vascular dysfunction. In particular, we discuss the emerging role played by different HIV-1 proteins in driving inflammation and EC dysregulation, and highlight the need to target them for therapeutic benefit. PMID:27602413

  19. Alternatively Activated Mononuclear Phagocytes from the Skin Site of Infection and the Impact of IL-4Rα Signalling on CD4+T Cell Survival in Draining Lymph Nodes after Repeated Exposure to Schistosoma mansoni Cercariae

    PubMed Central

    Prendergast, Catriona T.; Sanin, David E.; Mountford, Adrian P.

    2016-01-01

    In a murine model of repeated exposure of the skin to infective Schistosoma mansoni cercariae, events leading to the priming of CD4 cells in the skin draining lymph nodes were examined. The dermal exudate cell (DEC) population recovered from repeatedly (4x) exposed skin contained an influx of mononuclear phagocytes comprising three distinct populations according to their differential expression of F4/80 and MHC-II. As determined by gene expression analysis, all three DEC populations (F4/80-MHC-IIhigh, F4/80+MHC-IIhigh, F4/80+MHC-IIint) exhibited major up-regulation of genes associated with alternative activation. The gene encoding RELMα (hallmark of alternatively activated cells) was highly up-regulated in all three DEC populations. However, in 4x infected mice deficient in RELMα, there was no change in the extent of inflammation at the skin infection site compared to 4x infected wild-type cohorts, nor was there a difference in the abundance of different mononuclear phagocyte DEC populations. The absence of RELMα resulted in greater numbers of CD4+ cells in the skin draining lymph nodes (sdLN) of 4x infected mice, although they remained hypo-responsive. Using mice deficient for IL-4Rα, in which alternative activation is compromised, we show that after repeated schistosome infection, levels of regulatory IL-10 in the skin were reduced, accompanied by increased numbers of MHC-IIhigh cells and CD4+ T cells in the skin. There were also increased numbers of CD4+ T cells in the sdLN in the absence of IL-4Rα compared to cells from singly infected mice. Although their ability to proliferate was still compromised, increased cellularity of sdLN from 4x IL-4RαKO mice correlated with reduced expression of Fas/FasL, resulting in decreased apoptosis and cell death but increased numbers of viable CD4+ T cells. This study highlights a mechanism through which IL-4Rα may regulate the immune system through the induction of IL-10 and regulation of Fas/FasL mediated cell death

  20. Epithelial Cell Responses to Infection with Human Papillomavirus

    PubMed Central

    2012-01-01

    Summary: Human papillomavirus (HPV) infection of the genital tract is common in young sexually active individuals, the majority of whom clear the infection without overt clinical disease. Most of those who do develop benign lesions eventually mount an effective cell-mediated immune (CMI) response, and the lesions regress. Regression of anogenital warts is accompanied histologically by a CD4+ T cell-dominated Th1 response; animal models support this and provide evidence that the response is modulated by antigen-specific CD4+ T cell-dependent mechanisms. Failure to develop an effective CMI response to clear or control infection results in persistent infection and, in the case of the oncogenic HPVs, an increased probability of progression to high-grade intraepithelial neoplasia and invasive carcinoma. Effective evasion of innate immune recognition seems to be the hallmark of HPV infections. The viral infectious cycle is exclusively intraepithelial: there is no viremia and no virus-induced cytolysis or cell death, and viral replication and release are not associated with inflammation. HPV globally downregulates the innate immune signaling pathways in the infected keratinocyte. Proinflammatory cytokines, particularly the type I interferons, are not released, and the signals for Langerhans cell (LC) activation and migration, together with recruitment of stromal dendritic cells and macrophages, are either not present or inadequate. This immune ignorance results in chronic infections that persist over weeks and months. Progression to high-grade intraepithelial neoplasia with concomitant upregulation of the E6 and E7 oncoproteins is associated with further deregulation of immunologically relevant molecules, particularly chemotactic chemokines and their receptors, on keratinocytes and endothelial cells of the underlying microvasculature, limiting or preventing the ingress of cytotoxic effectors into the lesions. Recent evidence suggests that HPV infection of basal

  1. LAG3 Expression in Active Mycobacterium tuberculosis Infections

    PubMed Central

    Phillips, Bonnie L.; Mehra, Smriti; Ahsan, Muhammad H.; Selman, Moises; Khader, Shabaana A.; Kaushal, Deepak

    2016-01-01

    Mycobacterium tuberculosis (MTB) is a highly successful pathogen because of its ability to persist in human lungs for long periods of time. MTB modulates several aspects of the host immune response. Lymphocyte-activation gene 3 (LAG3) is a protein with a high affinity for the CD4 receptor and is expressed mainly by regulatory T cells with immunomodulatory functions. To understand the function of LAG3 during MTB infection, a nonhuman primate model of tuberculosis, which recapitulates key aspects of natural human infection in rhesus macaques (Macaca mulatta), was used. We show that the expression of LAG3 is highly induced in the lungs and particularly in the granulomatous lesions of macaques experimentally infected with MTB. Furthermore, we show that LAG3 expression is not induced in the lungs and lung granulomas of animals exhibiting latent tuberculosis infection. However, simian immunodeficiency virus–induced reactivation of latent tuberculosis infection results in an increased expression of LAG3 in the lungs. This response is not observed in nonhuman primates infected with non-MTB bacterial pathogens, nor with simian immunodeficiency virus alone. Our data show that LAG3 was expressed primarily on CD4+ T cells, presumably by regulatory T cells but also by natural killer cells. The expression of LAG3 coincides with high bacterial burdens and changes in the host type 1 helper T-cell response. PMID:25549835

  2. LAG3 expression in active Mycobacterium tuberculosis infections.

    PubMed

    Phillips, Bonnie L; Mehra, Smriti; Ahsan, Muhammad H; Selman, Moises; Khader, Shabaana A; Kaushal, Deepak

    2015-03-01

    Mycobacterium tuberculosis (MTB) is a highly successful pathogen because of its ability to persist in human lungs for long periods of time. MTB modulates several aspects of the host immune response. Lymphocyte-activation gene 3 (LAG3) is a protein with a high affinity for the CD4 receptor and is expressed mainly by regulatory T cells with immunomodulatory functions. To understand the function of LAG3 during MTB infection, a nonhuman primate model of tuberculosis, which recapitulates key aspects of natural human infection in rhesus macaques (Macaca mulatta), was used. We show that the expression of LAG3 is highly induced in the lungs and particularly in the granulomatous lesions of macaques experimentally infected with MTB. Furthermore, we show that LAG3 expression is not induced in the lungs and lung granulomas of animals exhibiting latent tuberculosis infection. However, simian immunodeficiency virus-induced reactivation of latent tuberculosis infection results in an increased expression of LAG3 in the lungs. This response is not observed in nonhuman primates infected with non-MTB bacterial pathogens, nor with simian immunodeficiency virus alone. Our data show that LAG3 was expressed primarily on CD4(+) T cells, presumably by regulatory T cells but also by natural killer cells. The expression of LAG3 coincides with high bacterial burdens and changes in the host type 1 helper T-cell response.

  3. Tracking and treating activated T cells

    PubMed Central

    Kim, N.H.; Nadithe, V.; Elsayed, M.; Merkel, O.M.

    2014-01-01

    Upon activation, T cells of various subsets are the most important mediators in cell-mediated immune responses. Activated T cells play an important role in immune system related diseases such as chronic inflammatory diseases, viral infections, autoimmune disease, transplant rejection, Crohn disease, diabetes, and many more. Therefore, efforts have been made to both visualize and treat activated T cells specifically. This review summarizes imaging approaches and selective therapeutics for activated T cells and gives an outlook on how tracking and treating can be combined into theragnositc agents for activated T cells. PMID:24660025

  4. TMEM2 inhibits hepatitis B virus infection in HepG2 and HepG2.2.15 cells by activating the JAK-STAT signaling pathway.

    PubMed

    Zhu, X; Xie, C; Li, Y-M; Huang, Z-L; Zhao, Q-Y; Hu, Z-X; Wang, P-P; Gu, Y-R; Gao, Z-L; Peng, L

    2016-01-01

    We have previously observed the downregulation of TMEM2 in the liver tissue of patients with chronic hepatitis B virus (HBV) infection and in HepG2.2.15 cells with HBV genomic DNA. In the present study, we investigated the role and mechanism of TMEM2 in HepG2 and HepG2.2.15 during HBV infection HepG2 and HepG2.2.15. HepG2 shTMEM2 cells with stable TMEM2 knockdown and HepG2 TMEM2 and HepG2.2.15 TMEM2 cells with stable TMEM2 overexpression were established using lentivirus vectors. We observed reduced expression of TMEM2 in HBV-infected liver tissues and HepG2.2.15 cells. HBsAg, HBcAg, HBV DNA, and HBV cccDNA levels were significantly increased in HepG2 shTMEM2 cells but decreased in HepG2 TMEM2 and HepG2.2.15 TMEM2 cells compared with naive HepG2 cells. On the basis of the western blotting results, the JAK-STAT signaling pathway was inhibited in HepG2 shTMEM2 cells but activated in HepG2 TMEM2 and HepG2.2.15 TMEM2 cells. In addition, reduced and increased expression of the antiviral proteins MxA and OAS1 was observed in TMEM2-silenced cells (HepG2 shTMEM2 cells) and TMEM2-overexpressing cells (HepG2 TMEM2 and HepG2.2.15 TMEM2 cells), respectively. The expression of Interferon regulatory factor 9 (IRF9) was not affected by TMEM2. However, we found that overexpression and knockdown of TMEM2, respectively, promoted and inhibited importation of IRF9 into nuclei. The luciferase reporter assay showed that IRF9 nuclear translocation affected interferon-stimulated response element activities. In addition, the inhibitory effects of TMEM2 on HBV infection in HepG2 shTMEM2 cells was significantly enhanced by pre-treatment with interferon but significantly inhibited in HepG2.2.15 TMEM2 cells by pre-treatment with JAK1 inhibitor. TMEM2 inhibits HBV infection in HepG2 and HepG2.2.15 by activating the JAK-STAT signaling pathway. PMID:27253403

  5. Peripheral Blood Cell Signatures of Plasmodium falciparum Infection during Pregnancy

    PubMed Central

    Ibitokou, Samad; Oesterholt, Mayke; Brutus, Laurent; Borgella, Sophie; Agbowaï, Carine; Ezinmègnon, Sèm; Lusingu, John; Schmiegelow, Christentze; Massougbodji, Achille; Deloron, Philippe; Troye-Blomberg, Marita; Varani, Stefania; Luty, Adrian J. F.; Fievet, Nadine

    2012-01-01

    Sequestration of Plasmodium falciparum-infected erythrocytes in placental intervillous spaces causes inflammation and pathology. Knowledge of the profiles of immune cells associated with the physiopathology of pregnancy-associated malaria (PAM) is scarce. We conducted a longitudinal, prospective study, both in Benin and Tanzania, including ∼1000 pregnant women in each site with systematic follow-up at scheduled antenatal visits until delivery. We used ex vivo flow cytometry to identify peripheral blood mononuclear cell (PBMC) profiles that are associated with PAM and anaemia, determining the phenotypic composition and activation status of PBMC in selected sub-groups with and without PAM both at inclusion and at delivery in a total of 302 women. Both at inclusion and at delivery PAM was associated with significantly increased frequencies both of B cells overall and of activated B cells. Infection-related profiles were otherwise quite distinct at the two different time-points. At inclusion, PAM was associated with anaemia, with an increased frequency of immature monocytes and with a decreased frequency of regulatory T cells (Treg). At delivery, infected women presented with significantly fewer plasmacytoid dendritic cells (DC), more myeloid DC expressing low levels of HLA-DR, and more effector T cells (Teff) compared to uninfected women. Independent associations with an increased risk of anaemia were found for altered antigen-presenting cell frequencies at inclusion, but for an increased frequency of Teff at delivery. Our findings emphasize the prominent role played by B cells during PAM whenever it arises during pregnancy, whilst also revealing signature changes in other circulating cell types that, we conclude, primarily reflect the relative duration of the infections. Thus, the acute, recently-acquired infections present at delivery were marked by changes in DC and Teff frequencies, contrasting with infections at inclusion, considered chronic in nature, that

  6. Activation of Plasmacytoid Dendritic Cells in Colon-Draining Lymph Nodes during Citrobacter rodentium Infection Involves Pathogen-Sensing and Inflammatory Pathways Distinct from Conventional Dendritic Cells.

    PubMed

    Toivonen, Raine; Kong, Lingjia; Rasool, Omid; Lund, Riikka J; Lahesmaa, Riitta; Hänninen, Arno

    2016-06-01

    Dendritic cells (DCs) bear the main responsibility for initiation of adaptive immune responses necessary for antimicrobial immunity. In the small intestine, afferent lymphatics convey Ags and microbial signals to mesenteric lymph nodes (LNs) to induce adaptive immune responses against microbes and food Ags derived from the small intestine. Whether the large intestine is covered by the same lymphatic system or represents its own lymphoid compartment has not been studied until very recently. We identified three small mesenteric LNs, distinct from small intestinal LNs, which drain lymph specifically from the colon, and studied DC responses to the attaching and effacing pathogen Citrobacter rodentium in these. Transcriptional profiling of conventional (CD11c(high)CD103(high)) DC and plasmacytoid (plasmacytoid DC Ag-1(high)B220(+)CD11c(int)) DC (pDC) populations during steady-state conditions revealed activity of distinct sets of genes in these two DC subsets, both in small intestinal and colon-draining LNs. C. rodentium activated DC especially in colon-draining LNs, and gene expression changed in pDC more profoundly than in conventional DC. Among the genes most upregulated in pDC were C-type lectin receptor CLEC4E, IL-1Rs (IL-1R1 and -2), proinflammatory cytokines (IL-1a and IL-6), and TLR6. Our results indicate that colon immune surveillance is distinct from that of the small intestine in terms of draining LNs, and identify pDC as active sentinels of colonic inflammation and/or microbial dysbiosis. PMID:27183629

  7. MAIT Cells Detect and Efficiently Lyse Bacterially-Infected Epithelial Cells

    PubMed Central

    Bohineust, Armelle; Bessoles, Stéphanie; Martin, Emmanuel; Premel, Virginie; Coré, Maxime; Sleurs, David; Serriari, Nacer-Eddine; Treiner, Emmanuel; Hivroz, Claire; Sansonetti, Philippe; Gougeon, Marie-Lise; Soudais, Claire; Lantz, Olivier

    2013-01-01

    Mucosal associated invariant T cells (MAIT) are innate T lymphocytes that detect a large variety of bacteria and yeasts. This recognition depends on the detection of microbial compounds presented by the evolutionarily conserved major-histocompatibility-complex (MHC) class I molecule, MR1. Here we show that MAIT cells display cytotoxic activity towards MR1 overexpressing non-hematopoietic cells cocultured with bacteria. The NK receptor, CD161, highly expressed by MAIT cells, modulated the cytokine but not the cytotoxic response triggered by bacteria infected cells. MAIT cells are also activated by and kill epithelial cells expressing endogenous levels of MRI after infection with the invasive bacteria Shigella flexneri. In contrast, MAIT cells were not activated by epithelial cells infected by Salmonella enterica Typhimurium. Finally, MAIT cells are activated in human volunteers receiving an attenuated strain of Shigella dysenteriae-1 tested as a potential vaccine. Thus, in humans, MAIT cells are the most abundant T cell subset able to detect and kill bacteria infected cells. PMID:24130485

  8. Aberrant CD8+ T-Cell Responses and Memory Differentiation upon Viral Infection of an Ataxia-Telangiectasia Mouse Model Driven by Hyper-Activated Akt and mTORC1 Signaling

    PubMed Central

    D'Souza, Anthony D.; Parish, Ian A.; McKay, Sharen E.; Kaech, Susan M.; Shadel, Gerald S.

    2011-01-01

    Immune system-related pathology is common in ataxia-telangiectasia (A-T) patients and mice that lack the protein kinase, A-T mutated (ATM). However, it has not been studied how ATM influences immune responses to a viral infection. Using the lymphocytic choriomeningitis virus (LCMV) infection model, we show that ATM−/− mice, despite having fewer naïve CD8+ T cells, effectively clear the virus. However, aberrant CD8+ T-cell responses are observed, including defective expansion and contraction, effector-to-memory differentiation, and a switch in viral-epitope immunodominance. T-cell receptor-activated, but not naïve, ATM−/− splenic CD8+ T cells have increased ribosomal protein S6 and Akt phosphorylation and do not proliferate well in response to IL-15, a cytokine important for memory T-cell development. Accordingly, pharmacological Akt or mammalian target of rapamycin complex 1 (mTORC1) inhibition during T-cell receptor activation alone rescues the IL-15 proliferation defect. Finally, rapamycin treatment during LCMV infection in vivo increases the number of memory T cells in ATM−/− mice. Altogether, these results show that CD8+ T cells lacking ATM have hyperactive Akt and mTORC1 signaling in response to T-cell receptor activation, which results in aberrant cytokine responses and memory T-cell development. We speculate that similar signaling defects contribute to the immune system pathology of A-T, and that inhibition of Akt and/or mTORC1 may be of therapeutic value. PMID:21641396

  9. T helper cell-mediated interferon-gamma expression after human parvovirus B19 infection: persisting VP2-specific and transient VP1u-specific activity.

    PubMed

    Franssila, R; Auramo, J; Modrow, S; Möbs, M; Oker-Blom, C; Käpylä, P; Söderlund-Venermo, M; Hedman, K

    2005-10-01

    Human parvovirus B19 is a small non-enveloped DNA virus with an icosahedral capsid consisting of proteins of only two species, the major protein VP2 and the minor protein VP1. VP2 is contained within VP1, which has an additional unique portion (VP1u) of 227 amino acids. We determined the ability of eukaryotically expressed parvovirus B19 virus-like particles consisting of VP1 and VP2 in the ratio recommended for vaccine use, or of VP2 alone, to stimulate, in an HLA class II restricted manner, peripheral blood mononuclear cells (PBMC) to proliferate and to secrete interferon gamma (IFN-gamma) and interleukin (IL)-10 cytokines among recently and remotely B19 infected subjects. PBMC reactivity with VP1u was determined specifically with a prokaryotically expressed VP1u antigen. In general, B19-specific IFN-gamma responses were stronger than IL-10 responses in both recent and remote infection; however, IL-10 responses were readily detectable among both groups, with the exception of patients with relapsed or persisting symptoms who showed strikingly low IL-10 responses. Whereas VP1u-specific IFN-gamma responses were very strong among the recently infected subjects, the VP1u-specific IFN-gamma and IL-10 responses were virtually absent among the remotely infected subjects. The disappearance of VP1u-specific IFN-gamma expression is surprising, as B-cell immunity against VP1u is well maintained.

  10. T helper cell-mediated interferon-gamma expression after human parvovirus B19 infection: persisting VP2-specific and transient VP1u-specific activity

    PubMed Central

    Franssila, R; Auramo, J; Modrow, S; Möbs, M; Oker-Blom, C; Käpylä, P; Söderlund-Venermo, M; Hedman, K

    2005-01-01

    Human parvovirus B19 is a small non-enveloped DNA virus with an icosahedral capsid consisting of proteins of only two species, the major protein VP2 and the minor protein VP1. VP2 is contained within VP1, which has an additional unique portion (VP1u) of 227 amino acids. We determined the ability of eukaryotically expressed parvovirus B19 virus-like particles consisting of VP1 and VP2 in the ratio recommended for vaccine use, or of VP2 alone, to stimulate, in an HLA class II restricted manner, peripheral blood mononuclear cells (PBMC) to proliferate and to secrete interferon gamma (IFN-γ) and interleukin (IL)-10 cytokines among recently and remotely B19 infected subjects. PBMC reactivity with VP1u was determined specifically with a prokaryotically expressed VP1u antigen. In general, B19-specific IFN-γ responses were stronger than IL-10 responses in both recent and remote infection; however, IL-10 responses were readily detectable among both groups, with the exception of patients with relapsed or persisting symptoms who showed strikingly low IL-10 responses. Whereas VP1u-specific IFN-γ responses were very strong among the recently infected subjects, the VP1u-specific IFN-γ and IL-10 responses were virtually absent among the remotely infected subjects. The disappearance of VP1u-specific IFN-γ expression is surprising, as B-cell immunity against VP1u is well maintained. PMID:16178856

  11. Pandemic Influenza A (H1N1) Virus Infection Increases Apoptosis and HIV-1 Replication in HIV-1 Infected Jurkat Cells.

    PubMed

    Wang, Xue; Tan, Jiying; Biswas, Santanu; Zhao, Jiangqin; Devadas, Krishnakumar; Ye, Zhiping; Hewlett, Indira

    2016-02-02

    Influenza virus infection has a significant impact on public health, since it is a major cause of morbidity and mortality. It is not well-known whether influenza virus infection affects cell death and human immunodeficiency virus (HIV)-1 replication in HIV-1-infected patients. Using a lymphoma cell line, Jurkat, we examined the in vitro effects of pandemic influenza A (H1N1) virus (pH1N1) infection on cell death and HIV-1 RNA production in infected cells. We found that pH1N1 infection increased apoptotic cell death through Fas and Bax-mediated pathways in HIV-1-infected Jurkat cells. Infection with pH1N1 virus could promote HIV-1 RNA production by activating host transcription factors including nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ĸB), nuclear factor of activated T-cells (NFAT) and activator protein 1 (AP-1) through mitogen-activated protein kinases (MAPK) pathways and T-cell antigen receptor (TCR)-related pathways. The replication of HIV-1 latent infection could be reactivated by pH1N1 infection through TCR and apoptotic pathways. These data indicate that HIV-1 replication can be activated by pH1N1 virus in HIV-1-infected cells resulting in induction of cell death through apoptotic pathways.

  12. 2-Octynoic Acid Inhibits Hepatitis C Virus Infection through Activation of AMP-Activated Protein Kinase

    PubMed Central

    Yang, Darong; Xue, Binbin; Wang, Xiaohong; Yu, Xiaoyan; Liu, Nianli; Gao, Yimin; Liu, Chen; Zhu, Haizhen

    2013-01-01

    Many chronic hepatitis C virus (HCV)-infected patients with current therapy do not clear the virus. It is necessary to find novel treatments. The effect of 2-octynoic acid (2-OA) on HCV infection in human hepatocytes was examined. The mechanism of 2-OA antiviral activity was explored. Our data showed that 2-OA abrogated lipid accumulation in HCV replicon cells and virus-infected hepatocytes. It suppressed HCV RNA replication and infectious virus production with no cytotoxicity to the host cells. 2-OA did not affect hepatitis B virus replication in HepG2.2.15 cells derived from HepG2 cells transfected with full genome of HBV. Further study demonstrated that 2-OA activated AMP-activated protein kinase (AMPK) and inhibited acetyl-CoA carboxylase in viral-infected cells. Compound C, a specific inhibitor of AMPK, inhibited AMPK activity and reversed the reduction of intracellular lipid accumulation and the antiviral effect of 2-OA. Knockdown of AMPK expression by RNA interference abolished the activation of AMPK by 2-OA and blocked 2-OA antiviral activity. Interestingly, 2-OA induced interferon-stimulated genes (ISGs) and inhibited microRNA-122 (miR-122) expression in virus-infected hepatocytes. MiR-122 overexpression reversed the antiviral effect of 2-OA. Furthermore, knockdown of AMPK expression reversed both the induction of ISGs and suppression of miR-122 by 2-OA, implying that activated AMPK induces the intracellular innate response through the induction of ISGs and inhibiting miR-122 expression. 2-OA inhibits HCV infection through regulation of innate immune response by activated AMPK. These findings reveal a novel mechanism by which active AMPK inhibits HCV infection. 2-OA and its derivatives hold promise for novel drug development for chronic hepatitis C. PMID:23741428

  13. Reconstitution of Intestinal CD4 and Th17 T Cells in Antiretroviral Therapy Suppressed HIV-Infected Subjects: Implication for Residual Immune Activation from the Results of a Clinical Trial

    PubMed Central

    d'Ettorre, Gabriella; Baroncelli, Silvia; Micci, Luca; Ceccarelli, Giancarlo; Andreotti, Mauro; Sharma, Prachi; Fanello, Gianfranco; Fiocca, Fausto; Cavallari, Eugenio Nelson; Giustini, Noemi; Mallano, Alessandra; Galluzzo, Clementina M.; Vella, Stefano; Mastroianni, Claudio M.; Silvestri, Guido; Paiardini, Mirko; Vullo, Vincenzo

    2014-01-01

    Introduction During HIV infection the severe depletion of intestinal CD4+ T-cells is associated with microbial translocation, systemic immune activation, and disease progression. This study examined intestinal and peripheral CD4+ T-cell subsets reconstitution under combined antiretroviral therapy (cART), and systemic immune activation markers. Methods This longitudinal single-arm pilot study evaluates CD4+ T cells, including Th1 and Th17, in gut and blood and soluble markers for inflammation in HIV-infected individuals before (M0) and after eight (M8) months of cART. From January 2010 to December 2011, 10 HIV-1 naïve patients were screened and 9 enrolled. Blood and gut CD4+ T-cells subsets and cellular immune activation were determined by flow-cytometry and plasma soluble CD14 by ELISA. CD4+ Th17 cells were detected in gut biopsies by immunohistochemistry. Microbial translocation was measured by limulus-amebocyte-lysate assay to detect bacterial lipopolysaccharide (LPS) and PCR Real Time to detect plasma bacterial 16S rDNA. Results Eight months of cART increased intestinal CD4+ and Th17 cells and reduced levels of T-cell activation and proliferation. The magnitude of intestinal CD4+ T-cell reconstitution correlated with the reduction of plasma LPS. Importantly, the magnitude of Th17 cells reconstitution correlated directly with blood CD4+ T-cell recovery. Conclusion Short-term antiretroviral therapy resulted in a significant increase in the levels of total and Th17 CD4+ T-cells in the gut mucosa and in decline of T-cell activation. The observation that pre-treatment levels of CD4+ and of CD8+ T-cell activation are predictors of the magnitude of Th17 cell reconstitution following cART provides further rationale for an early initiation of cART in HIV-infected individuals. Trial Registration ClinicalTrials.gov NCT02097381 PMID:25340778

  14. N-3 polyunsaturated fatty acids modulate B cell activity in pre-clinical models: Implications for the immune response to infections.

    PubMed

    Whelan, Jarrett; Gowdy, Kymberly M; Shaikh, Saame Raza

    2016-08-15

    B cell antigen presentation, cytokine production, and antibody production are targets of pharmacological intervention in inflammatory and infectious diseases. Here we review recent pre-clinical evidence demonstrating that pharmacologically relevant levels of n-3 polyunsaturated fatty acids (PUFA) derived from marine fish oils influence key aspects of B cell function through multiple mechanisms. N-3 PUFAs modestly diminish B cell mediated stimulation of classically defined naïve CD4(+) Th1 cells through the major histocompatibility complex (MHC) class II pathway. This is consistent with existing data showing that n-3 PUFAs suppress the activation of Th1/Th17 cells through direct effects on helper T cells and indirect effects on antigen presenting cells. Mechanistically, n-3 PUFAs lower antigen presentation and T cell signaling by disrupting the formation of lipid microdomains within the immunological synapse. We then review data to show that n-3 PUFAs boost B cell activation and antibody production in the absence and presence of antigen stimulation. This has potential benefits for several clinical populations such as the aged and obese that have poor humoral immunity. The mode of action by which n-3 PUFA boost B cell activation and antibody production remains unclear, but may involve Th2 cytokines, enhanced production of specialized proresolving lipid mediators, and targeting of protein lateral organization in lipid microdomains. Finally, we highlight evidence to show that different n-3 PUFAs are not biologically equivalent, which has implications for the development of future interventions to target B cell activity.

  15. EGFR regulates macrophage activation and function in bacterial infection.

    PubMed

    Hardbower, Dana M; Singh, Kshipra; Asim, Mohammad; Verriere, Thomas G; Olivares-Villagómez, Danyvid; Barry, Daniel P; Allaman, Margaret M; Washington, M Kay; Peek, Richard M; Piazuelo, M Blanca; Wilson, Keith T

    2016-09-01

    EGFR signaling regulates macrophage function, but its role in bacterial infection has not been investigated. Here, we assessed the role of macrophage EGFR signaling during infection with Helicobacter pylori, a bacterial pathogen that causes persistent inflammation and gastric cancer. EGFR was phosphorylated in murine and human macrophages during H. pylori infection. In human gastric tissues, elevated levels of phosphorylated EGFR were observed throughout the histologic cascade from gastritis to carcinoma. Deleting Egfr in myeloid cells attenuated gastritis and increased H. pylori burden in infected mice. EGFR deficiency also led to a global defect in macrophage activation that was associated with decreased cytokine, chemokine, and NO production. We observed similar alterations in macrophage activation and disease phenotype in the Citrobacter rodentium model of murine infectious colitis. Mechanistically, EGFR signaling activated NF-κB and MAPK1/3 pathways to induce cytokine production and macrophage activation. Although deletion of Egfr had no effect on DC function, EGFR-deficient macrophages displayed impaired Th1 and Th17 adaptive immune responses to H. pylori, which contributed to decreased chronic inflammation in infected mice. Together, these results indicate that EGFR signaling is central to macrophage function in response to enteric bacterial pathogens and is a potential therapeutic target for infection-induced inflammation and associated carcinogenesis.

  16. EGFR regulates macrophage activation and function in bacterial infection.

    PubMed

    Hardbower, Dana M; Singh, Kshipra; Asim, Mohammad; Verriere, Thomas G; Olivares-Villagómez, Danyvid; Barry, Daniel P; Allaman, Margaret M; Washington, M Kay; Peek, Richard M; Piazuelo, M Blanca; Wilson, Keith T

    2016-09-01

    EGFR signaling regulates macrophage function, but its role in bacterial infection has not been investigated. Here, we assessed the role of macrophage EGFR signaling during infection with Helicobacter pylori, a bacterial pathogen that causes persistent inflammation and gastric cancer. EGFR was phosphorylated in murine and human macrophages during H. pylori infection. In human gastric tissues, elevated levels of phosphorylated EGFR were observed throughout the histologic cascade from gastritis to carcinoma. Deleting Egfr in myeloid cells attenuated gastritis and increased H. pylori burden in infected mice. EGFR deficiency also led to a global defect in macrophage activation that was associated with decreased cytokine, chemokine, and NO production. We observed similar alterations in macrophage activation and disease phenotype in the Citrobacter rodentium model of murine infectious colitis. Mechanistically, EGFR signaling activated NF-κB and MAPK1/3 pathways to induce cytokine production and macrophage activation. Although deletion of Egfr had no effect on DC function, EGFR-deficient macrophages displayed impaired Th1 and Th17 adaptive immune responses to H. pylori, which contributed to decreased chronic inflammation in infected mice. Together, these results indicate that EGFR signaling is central to macrophage function in response to enteric bacterial pathogens and is a potential therapeutic target for infection-induced inflammation and associated carcinogenesis. PMID:27482886

  17. Preventing Infections in Sickle Cell Disease: The Unfinished Business.

    PubMed

    Obaro, Stephen K; Tam, P Y Iroh

    2016-05-01

    While encapsulated bacterial agents, particularly Streptococcus pneumoniae, are recognized as important microbes that are associated with serious illness in hosts with sickle cell disease (SCD), multiple pathogens are implicated in infectious manifestations of SCD. Variations in clinical practice have been an obstacle to the universal implementation of infection preventive management through active, targeted vaccination of these individuals and routine usage of antibiotic prophylaxis. Paradoxically, in low-income settings, there is evidence that SCD also increases the risk for several other infections that warrant additional infection preventive measures. The infection preventive care among patients with SCD in developed countries does not easily translate to the adoption of these recommendations globally, which must take into account the local epidemiology of infections, available vaccines and population-specific vaccine efficacy, environment, health care behaviors, and cultural beliefs, as these are all factors that play a complex role in the manifestation of SCD and the prevention of infectious disease morbidity.

  18. Preventing Infections in Sickle Cell Disease: The Unfinished Business.

    PubMed

    Obaro, Stephen K; Tam, P Y Iroh

    2016-05-01

    While encapsulated bacterial agents, particularly Streptococcus pneumoniae, are recognized as important microbes that are associated with serious illness in hosts with sickle cell disease (SCD), multiple pathogens are implicated in infectious manifestations of SCD. Variations in clinical practice have been an obstacle to the universal implementation of infection preventive management through active, targeted vaccination of these individuals and routine usage of antibiotic prophylaxis. Paradoxically, in low-income settings, there is evidence that SCD also increases the risk for several other infections that warrant additional infection preventive measures. The infection preventive care among patients with SCD in developed countries does not easily translate to the adoption of these recommendations globally, which must take into account the local epidemiology of infections, available vaccines and population-specific vaccine efficacy, environment, health care behaviors, and cultural beliefs, as these are all factors that play a complex role in the manifestation of SCD and the prevention of infectious disease morbidity. PMID:26840500

  19. Studying NK cell responses to ectromelia virus infections in mice.

    PubMed

    Fang, Min; Sigal, Luis

    2010-01-01

    Here we describe methods for the in vivo study of antiviral NK cell responses using the mouse Orthopoxvirus ectromelia virus as a model, the agent of mousepox. The methods include those specific for the preparation and use of ectromelia virus such as the production of virus stocks in tissue culture and in live mice, the purification of virus stocks, the titration of virus stocks and virus loads in organs, and the infection of mice. The chapter also includes methods for the specific study of NK cell responses in infected mice such as the preparation of organs (lymph nodes, spleen, and liver) for analysis, the study of NK cell responses by flow cytometry, the adoptive transfer of NK cells, the measurement of NK cell cytolytic activity ex vivo and in vivo, and the determination of NK cell proliferation by bromodeoxyuridine loading or by dilution of carboxyfluorescein diacetate succinimidyl ester (CFSE).

  20. Dual-color HIV reporters trace a population of latently infected cells and enable their purification.

    PubMed

    Calvanese, Vincenzo; Chavez, Leonard; Laurent, Timothy; Ding, Sheng; Verdin, Eric

    2013-11-01

    HIV latency constitutes the main barrier for clearing HIV infection from patients. Our inability to recognize and isolate latently infected cells hinders the study of latent HIV. We engineered two HIV-based viral reporters expressing different fluorescent markers: one HIV promoter-dependent marker for productive HIV infection, and a second marker under a constitutive promoter independent of HIV promoter activity. Infection of cells with these viruses allows the identification and separation of latently infected cells from uninfected and productively infected cells. These reporters are sufficiently sensitive and robust for high-throughput screening to identify drugs that reactivate latent HIV. These reporters can be used in primary CD4 T lymphocytes and reveal a rare population of latently infected cells responsive to physiological stimuli. In summary, our HIV-1 reporters enable visualization and purification of latent-cell populations and open up new perspectives for studies of latent HIV infection.

  1. Creation and characterization of a cell-death reporter cell line for hepatitis C virus infection

    PubMed Central

    Chen, Zhilei; Simeon, Rudo; Chockalingam, Karuppiah; Rice, Charles M.

    2010-01-01

    The present study describes the creation and characterization of a hepatoma cell line, n4mBid, that supports all stages of the hepatitis C virus (HCV) life cycle and strongly reports HCV infection by a cell-death phenotype. The n4mBid cell line is derived from the highly HCV-permissive Huh-7.5 hepatoma cell line and contains a modified Bid protein (mBid) that is cleaved and activated by the HCV serine protease NS3-4A. N4mBid exhibited a 10–20 fold difference in cell viability between the HCV-infected and mock-infected states, while the parental Huh-7.5 cells showed <2 fold difference under the same conditions. The pronounced difference in n4mBid cell viability between the HCV- and mock-infected states in a 96-well plate format points to its usefulness in cell survival-based high-throughput screens for anti-HCV molecules. The degree of cell death was found to be proportional to the intracellular load of HCV. HCV-low n4mBid cells, expressing an anti-HCV short hairpin RNA, showed a significant growth advantage over naïve cells and could be rapidly enriched after HCV infection, suggesting the possibility of using n4mBid cells for the cell survival-based selection of genetic anti-HCV factors. PMID:20188762

  2. Toxoplasma gondii Actively Inhibits Neuronal Function in Chronically Infected Mice

    PubMed Central

    Haroon, Fahad; Händel, Ulrike; Angenstein, Frank; Goldschmidt, Jürgen; Kreutzmann, Peter; Lison, Holger; Fischer, Klaus-Dieter; Scheich, Henning; Wetzel, Wolfram; Schlüter, Dirk; Budinger, Eike

    2012-01-01

    Upon infection with the obligate intracellular parasite Toxoplasma gondii, fast replicating tachyzoites infect a broad spectrum of host cells including neurons. Under the pressure of the immune response, tachyzoites convert into slow-replicating bradyzoites, which persist as cysts in neurons. Currently, it is unclear whether T. gondii alters the functional activity of neurons, which may contribute to altered behaviour of T. gondii–infected mice and men. In the present study we demonstrate that upon oral infection with T. gondii cysts, chronically infected BALB/c mice lost over time their natural fear against cat urine which was paralleled by the persistence of the parasite in brain regions affecting behaviour and odor perception. Detailed immunohistochemistry showed that in infected neurons not only parasitic cysts but also the host cell cytoplasm and some axons stained positive for Toxoplasma antigen suggesting that parasitic proteins might directly interfere with neuronal function. In fact, in vitro live cell calcium (Ca2+) imaging studies revealed that tachyzoites actively manipulated Ca2+ signalling upon glutamate stimulation leading either to hyper- or hypo-responsive neurons. Experiments with the endoplasmatic reticulum Ca2+ uptake inhibitor thapsigargin indicate that tachyzoites deplete Ca2+ stores in the endoplasmatic reticulum. Furthermore in vivo studies revealed that the activity-dependent uptake of the potassium analogue thallium was reduced in cyst harbouring neurons indicating their functional impairment. The percentage of non-functional neurons increased over time In conclusion, both bradyzoites and tachyzoites functionally silence infected neurons, which may significantly contribute to the altered behaviour of the host. PMID:22530040

  3. Modulation of MICA on the surface of Chlamydia trachomatis-infected endocervical epithelial cells promotes NK cell-mediated killing

    PubMed Central

    Ibana, Joyce Altamarino; Aiyar, Ashok; Quayle, Alison Jane; Schust, Danny Joseph

    2012-01-01

    Chlamydia trachomatis serovars D-K are obligate intracellular bacteria that have tropism for the columnar epithelial cells of the genital tract. Chlamydia trachomatis infection has been reported to induce modifications in immune cell ligand expression on epithelial host cells. In this study, we used an in vitro infection model that resulted in a partial infection of C. trachomatis-exposed primary-like immortalized endocervical epithelial cells (A2EN). Using this model, we demonstrated that expression of the natural killer (NK) cell activating ligand, MHC class I-related protein A (MICA), was upregulated on C. trachomatis-infected, but not on noninfected bystander cells. MICA upregulation was concomitant with MHC class I downregulation and impacted the susceptibility of C. trachomatis-infected cells to NK cell activity. The specificity of MICA upregulation was reflected by a higher cytolytic activity of an NK cell line (NK92MI) against C. trachomatis-infected cells compared with uninfected control cells. Significantly, data also indicated that NK cells exerted a partial, but incomplete sterilizing effect on C. trachomatis as shown by the reduction in recoverable inclusion forming units (IFU) when cocultured with C. trachomatis-infected cells. Taken together, our data suggest that NK cells may play a significant role in the ability of the host to counter C. trachomatis infection. PMID:22251247

  4. Immune parameters differentiating active from latent tuberculosis infection in humans.

    PubMed

    Lee, Ji Yeon; Jung, Young Won; Jeong, Ina; Joh, Joon-Sung; Sim, Soo Yeon; Choi, Boram; Jee, Hyeon-Gun; Lim, Dong-Gyun

    2015-12-01

    Tuberculosis remains a highly prevalent infectious disease worldwide. Identification of the immune parameters that differentiate active disease from latent infection will facilitate the development of efficient control measures as well as new diagnostic modalities for tuberculosis. Here, we investigated the cytokine production profiles of monocytes and CD4(+) T lymphocytes upon encountering mycobacterial antigens. In addition, cytokines and lipid mediators with immune-modulating activities were examined in plasma samples ex vivo. Comparison of these parameters in active tuberculosis patients and healthy subjects with latent infection revealed that, active tuberculosis was associated with diminished Th1-type cytokine secretion from CD4(+) T cells and less augmented inflammatory cytokine secretion from monocytes induced by IFN-γ than that in latent tuberculosis infection. In addition, a higher plasma concentration of lipoxin A4 and lower ratio of prostaglandin E2 to lipoxin A4 were observed in active cases than in latent infections. These findings have implications for preparing new therapeutic strategies and for differential diagnosis of the two types of tuberculosis infection.

  5. Kaposi's sarcoma-associated herpesvirus induces sustained NF-kappaB activation during de novo infection of primary human dermal microvascular endothelial cells that is essential for viral gene expression.

    PubMed

    Sadagopan, Sathish; Sharma-Walia, Neelam; Veettil, Mohanan Valiya; Raghu, Hari; Sivakumar, Ramu; Bottero, Virginie; Chandran, Bala

    2007-04-01

    In vitro Kaposi's sarcoma-associated herpesvirus (KSHV) infection of primary human dermal microvascular endothelial (HMVEC-d) cells and human foreskin fibroblast (HFF) cells is characterized by the induction of preexisting host signal cascades, sustained expression of latency-associated genes, transient expression of a limited number of lytic genes, and induction of several cytokines, growth factors, and angiogenic factors. Since NF-kappaB is a key molecule involved in the regulation of several of these factors, here, we examined NF-kappaB induction during de novo infection of HMVEC-d and HFF cells. Activation of NF-kappaB was observed as early as 5 to 15 min postinfection by KSHV, and translocation of p65-NF-kappaB into nuclei was detected by immunofluorescence assay, electrophoretic mobility shift assay, and p65 enzyme-linked immunosorbent assay. IkappaB phosphorylation inhibitor (Bay11-7082) reduced this activation significantly. A sustained moderate level of NF-kappaB induction was seen during the observed 72 h of in vitro KSHV latency. In contrast, high levels of ERK1/2 activation at earlier time points and a moderate level of activation at later times were observed. p38 mitogen-activated protein kinase was activated only at later time points, and AKT was activated in a cyclic manner. Studies with UV-inactivated KSHV suggested a role for virus entry stages in NF-kappaB induction and a requirement for KSHV viral gene expression in sustained induction. Inhibition of NF-kappaB did not affect target cell entry by KSHV but significantly reduced the expression of viral latent open reading frame 73 and lytic genes. KSHV infection induced the activation of several host transcription factors, including AP-1 family members, as well as several cytokines, growth factors, and angiogenic factors, which were significantly affected by NF-kappaB inhibition. These results suggest that during de novo infection, KSHV induces sustained levels of NF-kappaB to regulate viral and

  6. Dendritic Cells and Their Multiple Roles during Malaria Infection

    PubMed Central

    Amorim, Kelly N. S.; Chagas, Daniele C. G.; Sulczewski, Fernando B.

    2016-01-01

    Dendritic cells (DCs) play a central role in the initiation of adaptive immune responses, efficiently presenting antigens to T cells. This ability relies on the presence of numerous surface and intracellular receptors capable of sensing microbial components as well as inflammation and on a very efficient machinery for antigen presentation. In this way, DCs sense the presence of a myriad of pathogens, including Plasmodium spp., the causative agent of malaria. Despite many efforts to control this infection, malaria is still responsible for high rates of morbidity and mortality. Different groups have shown that DCs act during Plasmodium infection, and data suggest that the phenotypically distinct DCs subsets are key factors in the regulation of immunity during infection. In this review, we will discuss the importance of DCs for the induction of immunity against the different stages of Plasmodium, the outcomes of DCs activation, and also what is currently known about Plasmodium components that trigger such activation. PMID:27110574

  7. Secretion of Antonospora (Paranosema) locustae proteins into infected cells suggests an active role of microsporidia in the control of host programs and metabolic processes.

    PubMed

    Senderskiy, Igor V; Timofeev, Sergey A; Seliverstova, Elena V; Pavlova, Olga A; Dolgikh, Viacheslav V

    2014-01-01

    Molecular tools of the intracellular protozoan pathogens Apicomplexa and Kinetoplastida for manipulation of host cell machinery have been the focus of investigation for approximately two decades. Microsporidia, fungi-related microorganisms forming another large group of obligate intracellular parasites, are characterized by development in direct contact with host cytoplasm (the majority of species), strong minimization of cell machinery, and acquisition of unique transporters to exploit host metabolic system. All the aforementioned features are suggestive of the ability of microsporidia to modify host metabolic and regulatory pathways. Seven proteins of the microsporidium Antonospora (Paranosema) locustae with predicted signal peptides but without transmembrane domains were overexpressed in Escherichia coli. Western-blot analysis with antibodies against recombinant products showed secretion of parasite proteins from different functional categories into the infected host cell. Secretion of parasite hexokinase and α/β-hydrolase was confirmed by immunofluorescence microscopy. In addition, this method showed specific accumulation of A. locustae hexokinase in host nuclei. Expression of hexokinase, trehalase, and two leucine-rich repeat proteins without any exogenous signal peptide led to their secretion in the yeast Pichia pastoris. In contrast, α/β-hydrolase was not found in the culture medium, though a significant amount of this enzyme accumulated in the yeast membrane fraction. These results suggest that microsporidia possess a broad set of enzymes and regulatory proteins secreted into infected cells to control host metabolic processes and molecular programs. PMID:24705470

  8. Secretion of Antonospora (Paranosema) locustae Proteins into Infected Cells Suggests an Active Role of Microsporidia in the Control of Host Programs and Metabolic Processes

    PubMed Central

    Senderskiy, Igor V.; Timofeev, Sergey A.; Seliverstova, Elena V.; Pavlova, Olga A.; Dolgikh, Viacheslav V.

    2014-01-01

    Molecular tools of the intracellular protozoan pathogens Apicomplexa and Kinetoplastida for manipulation of host cell machinery have been the focus of investigation for approximately two decades. Microsporidia, fungi-related microorganisms forming another large group of obligate intracellular parasites, are characterized by development in direct contact with host cytoplasm (the majority of species), strong minimization of cell machinery, and acquisition of unique transporters to exploit host metabolic system. All the aforementioned features are suggestive of the ability of microsporidia to modify host metabolic and regulatory pathways. Seven proteins of the microsporidium Antonospora (Paranosema) locustae with predicted signal peptides but without transmembrane domains were overexpressed in Escherichia coli. Western-blot analysis with antibodies against recombinant products showed secretion of parasite proteins from different functional categories into the infected host cell. Secretion of parasite hexokinase and α/β-hydrolase was confirmed by immunofluorescence microscopy. In addition, this method showed specific accumulation of A. locustae hexokinase in host nuclei. Expression of hexokinase, trehalase, and two leucine-rich repeat proteins without any exogenous signal peptide led to their secretion in the yeast Pichia pastoris. In contrast, α/β-hydrolase was not found in the culture medium, though a significant amount of this enzyme accumulated in the yeast membrane fraction. These results suggest that microsporidia possess a broad set of enzymes and regulatory proteins secreted into infected cells to control host metabolic processes and molecular programs. PMID:24705470

  9. Human Ebola virus infection results in substantial immune activation.

    PubMed

    McElroy, Anita K; Akondy, Rama S; Davis, Carl W; Ellebedy, Ali H; Mehta, Aneesh K; Kraft, Colleen S; Lyon, G Marshall; Ribner, Bruce S; Varkey, Jay; Sidney, John; Sette, Alessandro; Campbell, Shelley; Ströher, Ute; Damon, Inger; Nichol, Stuart T; Spiropoulou, Christina F; Ahmed, Rafi

    2015-04-14

    Four Ebola patients received care at Emory University Hospital, presenting a unique opportunity to examine the cellular immune responses during acute Ebola virus infection. We found striking activation of both B and T cells in all four patients. Plasmablast frequencies were 10-50% of B cells, compared with less than 1% in healthy individuals. Many of these proliferating plasmablasts were IgG-positive, and this finding coincided with the presence of Ebola virus-specific IgG in the serum. Activated CD4 T cells ranged from 5 to 30%, compared with 1-2% in healthy controls. The most pronounced responses were seen in CD8 T cells, with over 50% of the CD8 T cells expressing markers of activation and proliferation. Taken together, these results suggest that all four patients developed robust immune responses during the acute phase of Ebola virus infection, a finding that would not have been predicted based on our current assumptions about the highly immunosuppressive nature of Ebola virus. Also, quite surprisingly, we found sustained immune activation after the virus was cleared from the plasma, observed most strikingly in the persistence of activated CD8 T cells, even 1 mo after the patients' discharge from the hospital. These results suggest continued antigen stimulation after resolution of the disease. From these convalescent time points, we identified CD4 and CD8 T-cell responses to several Ebola virus proteins, most notably the viral nucleoprotein. Knowledge of the viral proteins targeted by T cells during natural infection should be useful in designing vaccines against Ebola virus. PMID:25775592

  10. Human Ebola virus infection results in substantial immune activation.

    PubMed

    McElroy, Anita K; Akondy, Rama S; Davis, Carl W; Ellebedy, Ali H; Mehta, Aneesh K; Kraft, Colleen S; Lyon, G Marshall; Ribner, Bruce S; Varkey, Jay; Sidney, John; Sette, Alessandro; Campbell, Shelley; Ströher, Ute; Damon, Inger; Nichol, Stuart T; Spiropoulou, Christina F; Ahmed, Rafi

    2015-04-14

    Four Ebola patients received care at Emory University Hospital, presenting a unique opportunity to examine the cellular immune responses during acute Ebola virus infection. We found striking activation of both B and T cells in all four patients. Plasmablast frequencies were 10-50% of B cells, compared with less than 1% in healthy individuals. Many of these proliferating plasmablasts were IgG-positive, and this finding coincided with the presence of Ebola virus-specific IgG in the serum. Activated CD4 T cells ranged from 5 to 30%, compared with 1-2% in healthy controls. The most pronounced responses were seen in CD8 T cells, with over 50% of the CD8 T cells expressing markers of activation and proliferation. Taken together, these results suggest that all four patients developed robust immune responses during the acute phase of Ebola virus infection, a finding that would not have been predicted based on our current assumptions about the highly immunosuppressive nature of Ebola virus. Also, quite surprisingly, we found sustained immune activation after the virus was cleared from the plasma, observed most strikingly in the persistence of activated CD8 T cells, even 1 mo after the patients' discharge from the hospital. These results suggest continued antigen stimulation after resolution of the disease. From these convalescent time points, we identified CD4 and CD8 T-cell responses to several Ebola virus proteins, most notably the viral nucleoprotein. Knowledge of the viral proteins targeted by T cells during natural infection should be useful in designing vaccines against Ebola virus.

  11. Alteration of cell cycle progression by Sindbis virus infection

    SciTech Connect

    Yi, Ruirong; Saito, Kengo; Isegawa, Naohisa; Shirasawa, Hiroshi

    2015-07-10

    We examined the impact of Sindbis virus (SINV) infection on cell cycle progression in a cancer cell line, HeLa, and a non-cancerous cell line, Vero. Cell cycle analyses showed that SINV infection is able to alter the cell cycle progression in both HeLa and Vero cells, but differently, especially during the early stage of infection. SINV infection affected the expression of several cell cycle regulators (CDK4, CDK6, cyclin E, p21, cyclin A and cyclin B) in HeLa cells and caused HeLa cells to accumulate in S phase during the early stage of infection. Monitoring SINV replication in HeLa and Vero cells expressing cell cycle indicators revealed that SINV which infected HeLa cells during G{sub 1} phase preferred to proliferate during S/G{sub 2} phase, and the average time interval for viral replication was significantly shorter in both HeLa and Vero cells infected during G{sub 1} phase than in cells infected during S/G{sub 2} phase. - Highlights: • SINV infection was able to alter the cell cycle progression of infected cancer cells. • SINV infection can affect the expression of cell cycle regulators. • SINV infection exhibited a preference for the timing of viral replication among the cell cycle phases.

  12. Activation of the PI3K-Akt pathway by human T cell leukemia virus type 1 (HTLV-1) oncoprotein Tax increases Bcl3 expression, which is associated with enhanced growth of HTLV-1-infected T cells

    SciTech Connect

    Saito, Kousuke; Saito, Mineki; Taniura, Naoko; Okuwa, Takako; Ohara, Yoshiro

    2010-08-01

    Bcl3 is a member of the I{kappa}B family that regulates genes involved in cell proliferation and apoptosis. Recent reports indicated that Bcl3 is overexpressed in HTLV-1-infected T cells via Tax-mediated transactivation, and acts as a negative regulator of viral transcription. However, the role of Bcl3 in cellular signal transduction and the growth of HTLV-1-infected T cells have not been reported. In this study, we showed that the knockdown of Bcl3 by short hairpin RNA inhibited the growth of HTLV-1-infected T cells. Although phosphatidylinositol-3 kinase (PI3K) inhibitor reduced Bcl3 expression, inactivation of glycogen synthase kinase 3 (GSK3), an effector kinase of the PI3K/Akt signaling pathway, restored Bcl3 expression in Tax-negative but not in Tax-positive T cells. Our results indicate that the overexpression of Bcl3 in HTLV-1-infected T cells is regulated not only by transcriptional but also by post-transcriptional mechanisms, and is involved in overgrowth of HTLV-1-infected T cells.

  13. Combatting bacterial infections by killing persister cells with mitomycin C.

    PubMed

    Kwan, Brian W; Chowdhury, Nityananda; Wood, Thomas K

    2015-11-01

    Persister cells are a multi-drug tolerant subpopulation of bacteria that contribute to chronic and recalcitrant clinical infections such as cystic fibrosis and tuberculosis. Persisters are metabolically dormant, so they are highly tolerant to all traditional antibiotics which are mainly effective against actively growing cells. Here, we show that the FDA-approved anti-cancer drug mitomycin C (MMC) eradicates persister cells through a growth-independent mechanism. MMC is passively transported and bioreductively activated, leading to spontaneous cross-linking of DNA, which we verify in both active and dormant cells. We find MMC effectively eradicates cells grown in numerous different growth states (e.g. planktonic cultures and highly robust biofilm cultures) in both rich and minimal media. Additionally, MMC is a potent bactericide for a broad range of bacterial persisters, including commensal Escherichia coli K-12 as well as pathogenic species of E. coli, Staphylococcus aureus and Pseudomonas aeruginosa. We also demonstrate the efficacy of MMC in an animal model and a wound model, substantiating the clinical applicability of MMC against bacterial infections. Therefore, MMC is the first broad-spectrum compound capable of eliminating persister cells, meriting investigation as a new approach for the treatment of recalcitrant infections. PMID:25858802

  14. Combatting bacterial infections by killing persister cells with mitomycin C.

    PubMed

    Kwan, Brian W; Chowdhury, Nityananda; Wood, Thomas K

    2015-11-01

    Persister cells are a multi-drug tolerant subpopulation of bacteria that contribute to chronic and recalcitrant clinical infections such as cystic fibrosis and tuberculosis. Persisters are metabolically dormant, so they are highly tolerant to all traditional antibiotics which are mainly effective against actively growing cells. Here, we show that the FDA-approved anti-cancer drug mitomycin C (MMC) eradicates persister cells through a growth-independent mechanism. MMC is passively transported and bioreductively activated, leading to spontaneous cross-linking of DNA, which we verify in both active and dormant cells. We find MMC effectively eradicates cells grown in numerous different growth states (e.g. planktonic cultures and highly robust biofilm cultures) in both rich and minimal media. Additionally, MMC is a potent bactericide for a broad range of bacterial persisters, including commensal Escherichia coli K-12 as well as pathogenic species of E. coli, Staphylococcus aureus and Pseudomonas aeruginosa. We also demonstrate the efficacy of MMC in an animal model and a wound model, substantiating the clinical applicability of MMC against bacterial infections. Therefore, MMC is the first broad-spectrum compound capable of eliminating persister cells, meriting investigation as a new approach for the treatment of recalcitrant infections.

  15. 6K2-induced vesicles can move cell to cell during turnip mosaic virus infection.

    PubMed

    Grangeon, Romain; Jiang, Jun; Wan, Juan; Agbeci, Maxime; Zheng, Huanquan; Laliberté, Jean-François

    2013-01-01

    To successfully infect plants, viruses replicate in an initially infected cell and then move to neighboring cells through plasmodesmata (PDs). However, the nature of the viral entity that crosses over the cell barrier into non-infected ones is not clear. The membrane-associated 6K2 protein of turnip mosaic virus (TuMV) induces the formation of vesicles involved in the replication and intracellular movement of viral RNA. This study shows that 6K2-induced vesicles trafficked toward the plasma membrane and were associated with plasmodesmata (PD). We demonstrated also that 6K2 moved cell-to-cell into adjoining cells when plants were infected with TuMV. 6K2 was then fused to photo-activable GFP (6K2:PAGFP) to visualize how 6K2 moved intercellularly during TuMV infection. After activation, 6K2:PAGFP-tagged vesicles moved to the cell periphery and across the cell wall into adjacent cells. These vesicles were shown to contain the viral RNA-dependent RNA polymerase and viral RNA. Symplasmic movement of TuMV may thus be achieved in the form of a membrane-associated viral RNA complex induced by 6K2. PMID:24409170

  16. Glycosaminoglycan receptors facilitate infection of mammalian cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A growing list of viruses has been reported to use more than one receptor for binding and internalization during infection of the host cell. Sialic acid residues or glycosaminoglycans, such as heparin sulfate, frequently function in this scenario, as a first contact, charge based, low affinity bindi...

  17. Demonstration of NK cell-mediated lysis of varicella-zoster virus (VZV)-infected cells: characterization of the effector cells

    SciTech Connect

    Tilden, A.B.; Cauda, R.; Grossi, C.E.; Balch, C.M.; Lakeman, A.D.; Whitley, R.J.

    1986-06-01

    Infection with varicella-zoster virus (VZV) rendered RAJI cells more susceptible to lysis by non-adherent blood lymphocytes. At an effector to target ratio of 80:1 the mean percentage of /sup 51/Cr release of VZV-infected RAJI cells was 41 +/- 12%, whereas that of uninfected RAJI cells was 15 +/- 6%. The increased susceptibility to lysis was associated with increased effector to target conjugate formation in immunofluorescence binding assays. The effector cells cytotoxic for VZV-infected RAJI cells were predominantly Leu-11a/sup +/ Leu-4/sup -/ granular lymphocytes as demonstrated by fluorescence-activated cell sorting. The effector cell active against VZV-infected RAJI cells appeared similar to those active against herpes simplex virus (HSV)-infected cells, because in cold target competition experiments the lysis of /sup 51/Cr-labeled VZV-infected RAJI cells was efficiently inhibited by either unlabeled VZV-infected RAJI cells (mean 71% inhibition, 2:1 ratio unlabeled to labeled target) or HSV-infected RAJI cells (mean 69% inhibition) but not by uninfected RAJI cells (mean 10% inhibition). In contrast, competition experiments revealed donor heterogeneity in the overlap between effector cells for VZV- or HSV-infected RAJI vs K-562 cells.

  18. Glycolytic control of vacuolar-type ATPase activity: A mechanism to regulate influenza viral infection

    SciTech Connect

    Kohio, Hinissan P.; Adamson, Amy L.

    2013-09-15

    As new influenza virus strains emerge, finding new mechanisms to control infection is imperative. In this study, we found that we could control influenza infection of mammalian cells by altering the level of glucose given to cells. Higher glucose concentrations induced a dose-specific increase in influenza infection. Linking influenza virus infection with glycolysis, we found that viral replication was significantly reduced after cells were treated with glycolytic inhibitors. Addition of extracellular ATP after glycolytic inhibition restored influenza infection. We also determined that higher levels of glucose promoted the assembly of the vacuolar-type ATPase within cells, and increased vacuolar-type ATPase proton-transport activity. The increase of viral infection via high glucose levels could be reversed by inhibition of the proton pump, linking glucose metabolism, vacuolar-type ATPase activity, and influenza viral infection. Taken together, we propose that altering glucose metabolism may be a potential new approach to inhibit influenza viral infection. - Highlights: • Increased glucose levels increase Influenza A viral infection of MDCK cells. • Inhibition of the glycolytic enzyme hexokinase inhibited Influenza A viral infection. • Inhibition of hexokinase induced disassembly the V-ATPase. • Disassembly of the V-ATPase and Influenza A infection was bypassed with ATP. • The state of V-ATPase assembly correlated with Influenza A infection of cells.

  19. Spectroscopic investigation of herpes simplex viruses infected cells and their response to antiviral therapy

    NASA Astrophysics Data System (ADS)

    Erukhimovitch, Vitaly; Talyshinsky, Marina; Souprun, Yelena; Huleihel, Mahmoud

    2006-07-01

    In the present study, we used microscopic Fourier transform infrared spectroscopy (FTIR) to evaluate the antiviral activity of known antiviral agents against herpes viruses. The antiviral activity of Caffeic acid phenethyl ester (CAPE) (which is an active compound of propolis) against herpes simplex type 1 and 2 was examined in cell culture. The advantage of microscopic FTIR spectroscopy over conventional FTIR spectroscopy is that it facilitates inspection of restricted regions of cell culture or tissue. Our results showed significant spectral differences at early stages of infection between infected and non-infected cells, and between infected cells treated with the used antiviral agent and those not treated. In infected cells, there was a considerable increase in phosphate levels. Our results show that treatment with used antiviral agent considerably abolish the spectral changes induced by the viral infection. In addition, it is possible to track by FTIR microscopy method the deferential effect of various doses of the drug.

  20. Dengue-2 virus infection of human mononuclear cell lines and establishment of persistent infections.

    PubMed

    Kurane, I; Kontny, U; Janus, J; Ennis, F A

    1990-01-01

    Twenty three human mononuclear cell lines including ten myelomonocytic cell lines, eight B cell lines and five T cell lines, were examined to determine whether they could be infected with dengue-2 virus. All the cell lines were infected with dengue-2 virus as determined by immunofluorescent staining and by virus titration of culture supernatant fluids. K562, Jiyoye and Jurkat, respectively, showed the highest percentage of infected cells of these myelomonocytic, B and T cell lines. Antibody to dengue-2 virus at subneutralizing concentrations augmented dengue-2 virus infection of myelomonocytic cell lines, but not of B cell lines or of T cell lines. Persistent dengue-2 virus infection was established using a myelomonocytic cell line (K562), a B cell line (Raji), and a T cell line (HSB-2). These cell lines maintained a high percentage (more than 70%) of dengue-2 virus antigen-positive cells for at least 25 weeks. Very low titers of infectious dengue-2 virus were detected in the culture supernatant fluids of the persistently infected cells. Dengue-2 virus antigen-positive Raji cell clones were established from persistently-infected Raji cells using limiting dilutions and all of the cells in these clones were dengue-2 virus antigen-positive. These findings demonstrate that a variety of human mononuclear cell lines can be infected with dengue-2 virus and may be useful as models for the analysis of dengue virus-human cell interactions in dengue virus infections.

  1. Infection of human synovial cells by human T cell lymphotropic virus type I. Proliferation and granulocyte/macrophage colony-stimulating factor production by synovial cells.

    PubMed Central

    Sakai, M; Eguchi, K; Terada, K; Nakashima, M; Yamashita, I; Ida, H; Kawabe, Y; Aoyagi, T; Takino, H; Nakamura, T

    1993-01-01

    The present study was performed to clarify the relationship between human T cell lymphotropic virus type I (HTLV-I) infection and chronic inflammatory arthropathy. To determine the ability of HTLV-I to infect synovial cells and the effect on synovial cell proliferation, synovial cells were cocultured with the HTLV-I-producing T cell lines (MT-2 or HCT-1). After coculture with HTLV-I-infected T cells, the synovial cells expressed HTLV-I-specific core antigens, and HTLV-I proviral DNA was detected from the synovial cells by polymerase chain reaction. These cocultured synovial cells with HTLV-I-infected T cells proliferated more actively than the synovial cells cocultured with uninfected T cells. This stimulatory effect of HTLV-I-infected T cells on synovial cell proliferation seems necessary to contact each other. After being cocultured with MT-2 cells, synovial cells proliferated more actively than control cells even after several passages. Furthermore, HTLV-I-infected synovial cells produced significant amounts of granulocyte/macrophage colony-stimulating factor. These results suggest that HTLV-I can infect synovial cells, resulting their active proliferation and may be involved in the pathogenesis of proliferative synovitis similar to that found in rheumatoid arthritis. Images PMID:8408648

  2. T cell exhaustion during persistent viral infections.

    PubMed

    Kahan, Shannon M; Wherry, E John; Zajac, Allan J

    2015-05-01

    Although robust and highly effective anti-viral T cells contribute to the clearance of many acute infections, viral persistence is associated with the development of functionally inferior, exhausted, T cell responses. Exhaustion develops in a step-wise and progressive manner, ranges in severity, and can culminate in the deletion of the anti-viral T cells. This disarming of the response is consequential as it compromises viral control and potentially serves to dampen immune-mediated damage. Exhausted T cells are unable to elaborate typical anti-viral effector functions. They are characterized by the sustained upregulation of inhibitory receptors and display a gene expression profile that distinguishes them from prototypic effector and memory T cell populations. In this review we discuss the properties of exhausted T cells; the virological and immunological conditions that favor their development; the cellular and molecular signals that sustain the exhausted state; and strategies for preventing and reversing exhaustion to favor viral control.

  3. Bioactive Molecules Released From Cells Infected with the Human Cytomegalovirus.

    PubMed

    Luganini, Anna; Terlizzi, Maria E; Gribaudo, Giorgio

    2016-01-01

    Following primary infection in humans, the human cytomegalovirus (HCMV) persists in a latent state throughout the host's lifetime despite a strong and efficient immune response. If the host experiences some form of immune dysregulation, such as immunosuppression or immunodeficiency, HCMV reactivates, thereby emerging from latency. Thus, in the absence of effective functional immune responses, as occurs in immunocompromised or immunoimmature individuals, both HCMV primary infections and reactivations from latency can cause significant morbidity and mortality. However, even in immunocompetent hosts, HCMV represents a relevant risk factor for the development of several chronic inflammatory diseases and certain forms of neoplasia. HCMV infection may shift between the lytic and latent state, regulated by a delicate and intricate balance between virus-mediated immunomodulation and host immune defenses. Indeed, HCMV is a master in manipulating innate and adaptive host defense pathways, and a large portion of its genome is devoted to encoding immunomodulatory proteins; such proteins may thus represent important virulence determinants. However, the pathogenesis of HCMV-related diseases is strengthened by the activities of bioactive molecules, of both viral and cellular origin, that are secreted from infected cells and collectively named as the secretome. Here, we review the state of knowledge on the composition and functions of HCMV-derived secretomes. In lytic infections of fibroblasts and different types of endothelial cells, the majority of HCMV-induced secreted proteins act in a paracrine fashion to stimulate the generation of an inflammatory microenvironment around infected cells; this may lead to vascular inflammation and angiogenesis that, in turn, foster HCMV replication and its dissemination through host tissues. Conversely, the HCMV secretome derived from latently infected hematopoietic progenitor cells induces an immunosuppressive extracellular environment that

  4. Bioactive Molecules Released From Cells Infected with the Human Cytomegalovirus

    PubMed Central

    Luganini, Anna; Terlizzi, Maria E.; Gribaudo, Giorgio

    2016-01-01

    Following primary infection in humans, the human cytomegalovirus (HCMV) persists in a latent state throughout the host’s lifetime despite a strong and efficient immune response. If the host experiences some form of immune dysregulation, such as immunosuppression or immunodeficiency, HCMV reactivates, thereby emerging from latency. Thus, in the absence of effective functional immune responses, as occurs in immunocompromised or immunoimmature individuals, both HCMV primary infections and reactivations from latency can cause significant morbidity and mortality. However, even in immunocompetent hosts, HCMV represents a relevant risk factor for the development of several chronic inflammatory diseases and certain forms of neoplasia. HCMV infection may shift between the lytic and latent state, regulated by a delicate and intricate balance between virus-mediated immunomodulation and host immune defenses. Indeed, HCMV is a master in manipulating innate and adaptive host defense pathways, and a large portion of its genome is devoted to encoding immunomodulatory proteins; such proteins may thus represent important virulence determinants. However, the pathogenesis of HCMV-related diseases is strengthened by the activities of bioactive molecules, of both viral and cellular origin, that are secreted from infected cells and collectively named as the secretome. Here, we review the state of knowledge on the composition and functions of HCMV-derived secretomes. In lytic infections of fibroblasts and different types of endothelial cells, the majority of HCMV-induced secreted proteins act in a paracrine fashion to stimulate the generation of an inflammatory microenvironment around infected cells; this may lead to vascular inflammation and angiogenesis that, in turn, foster HCMV replication and its dissemination through host tissues. Conversely, the HCMV secretome derived from latently infected hematopoietic progenitor cells induces an immunosuppressive extracellular environment that

  5. Infection-mimicking materials to program dendritic cells in situ

    NASA Astrophysics Data System (ADS)

    Ali, Omar A.; Huebsch, Nathaniel; Cao, Lan; Dranoff, Glenn; Mooney, David J.

    2009-02-01

    Cancer vaccines typically depend on cumbersome and expensive manipulation of cells in the laboratory, and subsequent cell transplantation leads to poor lymph-node homing and limited efficacy. We propose that materials mimicking key aspects of bacterial infection may instead be used to directly control immune-cell trafficking and activation in the body. It is demonstrated that polymers can be designed to first release a cytokine to recruit and house host dendritic cells, and subsequently present cancer antigens and danger signals to activate the resident dendritic cells and markedly enhance their homing to lymph nodes. Specific and protective anti-tumour immunity was generated with these materials, as 90% survival was achieved in animals that otherwise die from cancer within 25days. These materials show promise as cancer vaccines, and more broadly suggest that polymers may be designed to program and control the trafficking of a variety of cell types in the body.

  6. Activities of dl-α-Difluoromethylarginine and Polyamine Analogues against Cryptosporidium parvum Infection in a T-Cell Receptor Alpha-Deficient Mouse Model▿

    PubMed Central

    Yarlett, Nigel; Waters, W. Ray; Harp, James A.; Wannemuehler, Michael J.; Morada, Mary; Bellcastro, Josephine; Upton, Steve J.; Marton, Laurence J.; Frydman, Benjamin J.

    2007-01-01

    The in vivo effectiveness of a series of conformationally restricted polyamine analogues alone and selected members in combination with dl-α-difluoromethylarginine against Cryptosporidium parvum infection in a T-cell receptor alpha-deficient mouse model was tested. Polyamine analogues were selected from the extended bis(ethyl)-sym-homospermidine or bis(ethyl)-spermine backbone having cis or trans double bonds at the center of the molecule. The cis isomers were found to have significantly greater efficacy in both preventing and curing infection in a mouse model than the trans polyamine analogues when tested in a T-cell receptor alpha-deficient mouse model. When tested in combination with dl-α-difluoromethylarginine, the cis-restricted analogues were found to be more effective in preventing oocyst shedding. This study demonstrates the potential of polyamine analogues as anticryptosporidial agents and highlights the presence of multiple points in polyamine synthesis by this parasite that are susceptible to inhibition resulting in growth inhibition. PMID:17242149

  7. Human Papillomavirus Infections in Nonsexually Active Perinatally HIV Infected Children

    PubMed Central

    Puga, Ana; Farhat, Sepideh; Ma, Yifei

    2014-01-01

    Abstract Although human papillomavirus (HPV) infections are common in HIV-infected adults, little is known about children. Our objective was to examine the prevalence of and risks for HPV of the oral mucosal and external genital areas in nonsexually active (NSA) perinatally (P) HIV+ children and compare with HIV-exposed but uninfected (HEU) children. A convenience sample attending a pediatric clinic were enrolled. Samples for HPV were obtained from the oral and anogenital areas and tested for one of 37 HPV types. The mean age of the 48 PHIV+ children was 14.3±3.9 years vs. 6.2±4.8 for the 52 HEU (p<0.001). Of the 23 PHIV+ girls, 30.4% had anogenital and 17% had oral HPV, and of the 27 HEU girls, 2 (7.4%) anogenital and 0 had oral HPV. Of the boys, 4/23 (17.4%) and 1/25 (4%) PHIV+ had anogenital and oral HPV, respectively, and 3/24 (12.5%) and 1/25 (4%) HEU had anogenital and oral HPV, respectively. Rates of HPV did not differ by age among the PHIV+, whereas older HEU were more likely to have HPV than younger HEU (p=0.07). This large age gap precluded statistical comparison by HIV status. The presence of HPV in NSA PHIV+ children may have implications regarding HPV vaccination efficacy. PMID:24460009

  8. Modelling and analysis of dynamics of viral infection of cells and of interferon resistance

    NASA Astrophysics Data System (ADS)

    Getto, Ph.; Kimmel, M.; Marciniak-Czochra, A.

    2008-08-01

    Interferons are active biomolecules, which help fight viral infections by spreading from infected to uninfected cells and activate effector molecules, which confer resistance from the virus on cells. We propose a new model of dynamics of viral infection, including endocytosis, cell death, production of interferon and development of resistance. The novel element is a specific biologically justified mechanism of interferon action, which results in dynamics different from other infection models. The model reflects conditions prevailing in liquid cultures (ideal mixing), and the absence of cells or virus influx from outside. The basic model is a nonlinear system of five ordinary differential equations. For this variant, it is possible to characterise global behaviour, using a conservation law. Analytic results are supplemented by computational studies. The second variant of the model includes age-of-infection structure of infected cells, which is described by a transport-type partial differential equation for infected cells. The conclusions are: (i) If virus mortality is included, the virus becomes eventually extinct and subpopulations of uninfected and resistant cells are established. (ii) If virus mortality is not included, the dynamics may lead to extinction of uninfected cells. (iii) Switching off the interferon defense results in a decrease of the sum total of uninfected and resistant cells. (iv) Infection-age structure of infected cells may result in stabilisation or destabilisation of the system, depending on detailed assumptions. Our work seems to constitute the first comprehensive mathematical analysis of the cell-virus-interferon system based on biologically plausible hypotheses.

  9. SAMHD1 controls cell cycle status, apoptosis and HIV-1 infection in monocytic THP-1 cells.

    PubMed

    Bonifati, Serena; Daly, Michele B; St Gelais, Corine; Kim, Sun Hee; Hollenbaugh, Joseph A; Shepard, Caitlin; Kennedy, Edward M; Kim, Dong-Hyun; Schinazi, Raymond F; Kim, Baek; Wu, Li

    2016-08-01

    SAMHD1 limits HIV-1 infection in non-dividing myeloid cells by decreasing intracellular dNTP pools. HIV-1 restriction by SAMHD1 in these cells likely prevents activation of antiviral immune responses and modulates viral pathogenesis, thus highlighting a critical role of SAMHD1 in HIV-1 physiopathology. Here, we explored the function of SAMHD1 in regulating cell proliferation, cell cycle progression and apoptosis in monocytic THP-1 cells. Using the CRISPR/Cas9 technology, we generated THP-1 cells with stable SAMHD1 knockout. We found that silencing of SAMHD1 in cycling cells stimulates cell proliferation, redistributes cell cycle population in the G1/G0 phase and reduces apoptosis. These alterations correlated with increased dNTP levels and more efficient HIV-1 infection in dividing SAMHD1 knockout cells relative to control. Our results suggest that SAMHD1, through its dNTPase activity, affects cell proliferation, cell cycle distribution and apoptosis, and emphasize a key role of SAMHD1 in the interplay between cell cycle regulation and HIV-1 infection. PMID:27183329

  10. Canine Distemper Virus Epithelial Cell Infection Is Required for Clinical Disease but Not for Immunosuppression

    PubMed Central

    Sawatsky, Bevan; Wong, Xiao-Xiang; Hinkelmann, Sarah; Cattaneo, Roberto

    2012-01-01

    To characterize the importance of infection of epithelial cells for morbillivirus pathogenesis, we took advantage of the severe disease caused by canine distemper virus (CDV) in ferrets. To obtain a CDV that was unable to enter epithelial cells but retained the ability to enter immune cells, we transferred to its attachment (H) protein two mutations shown to interfere with the interaction of measles virus H with its epithelial receptor, human nectin-4. As expected for an epithelial receptor (EpR)-blind CDV, this virus infected dog and ferret epithelial cells inefficiently and did not cause cell fusion or syncytium formation. On the other hand, the EpR-blind CDV replicated in cells expressing canine signaling lymphocyte activation molecule (SLAM), the morbillivirus immune cell receptor, with similar kinetics to those of wild-type CDV. While ferrets infected with wild-type CDV died within 12 days after infection, after developing severe rash and fever, animals infected with the EpR-blind virus showed no clinical signs of disease. Nevertheless, both viruses spread rapidly and efficiently in immune cells, causing similar levels of leukopenia and inhibition of lymphocyte proliferation activity, two indicators of morbillivirus immunosuppression. Infection was documented for airway epithelia of ferrets infected with wild-type CDV but not for those of animals infected with the EpR-blind virus, and only animals infected with wild-type CDV shed virus. Thus, epithelial cell infection is necessary for clinical disease and efficient virus shedding but not for immunosuppression. PMID:22278252

  11. Plasmodium Infection Promotes Genomic Instability and AID Dependent B Cell Lymphoma

    PubMed Central

    Robbiani, Davide F.; Deroubaix, Stephanie; Feldhahn, Niklas; Oliveira, Thiago Y.; Callen, Elsa; Wang, Qiao; Jankovic, Mila; Silva, Israel T.; Rommel, Philipp C.; Bosque, David; Eisenreich, Tom; Nussenzweig, André; Nussenzweig, Michel C.

    2015-01-01

    Summary Chronic infection with Plasmodium falciparum was epidemiologically associated with endemic Burkitt’s lymphoma, a mature B cell cancer characterized by chromosome translocation between the c-myc oncogene and Igh, over 50 years ago. Whether infection promotes B cell lymphoma, and if so by what mechanism remains unknown. To investigate the relationship between parasitic disease and lymphomagenesis we used Plasmodium chabaudi (Pc) to produce chronic malaria infection in mice. Pc induces prolonged expansion of germinal centers (GCs), unique compartments where B cells undergo rapid clonal expansion and express activation-induced cytidine deaminase (AID), a DNA mutator. GC B cells elicited during Pc infection suffer widespread DNA damage leading to chromosome translocations. Although infection does not change the overall rate, it modifies lymphomagenesis to favor mature B cell lymphomas that are AID dependent and show chromosome translocations. Thus, malaria infection favors mature B cell cancers by eliciting protracted AID expression in GC B cells. PMID:26276629

  12. Airway epithelial cell response to human metapneumovirus infection

    SciTech Connect

    Bao, X.; Liu, T.; Spetch, L.; Kolli, D.; Garofalo, R.P.; Casola, A.

    2007-11-10

    Human metapneumovirus (hMPV) is a major cause of lower respiratory tract infections (LRTIs) in infants, elderly and immunocompromised patients. In this study, we show that hMPV can infect in a similar manner epithelial cells representative of different tracts of the airways. hMPV-induced expression of chemokines IL-8 and RANTES in primary small alveolar epithelial cells (SAE) and in a human alveolar type II-like epithelial cell line (A549) was similar, suggesting that A549 cells can be used as a model to study lower airway epithelial cell responses to hMPV infection. A549 secreted a variety of CXC and CC chemokines, cytokines and type I interferons, following hMPV infection. hMPV was also a strong inducer of transcription factors belonging to nuclear factor (NF)-{kappa}B, interferon regulatory factors (IRFs) and signal transducers and activators of transcription (STATs) families, which are known to orchestrate the expression of inflammatory and immunomodulatory mediators.

  13. Regulatory T cells and the immune pathogenesis of prenatal infection.

    PubMed

    Rowe, Jared H; Ertelt, James M; Xin, Lijun; Way, Sing Sing

    2013-12-01

    Pregnancy in placental mammals offers exceptional comprehensive benefits of in utero protection, nutrition, and metabolic waste elimination for the developing fetus. However, these benefits also require durable strategies to mitigate maternal rejection of fetal tissues expressing foreign paternal antigens. Since the initial postulate of expanded maternal immune tolerance by Sir Peter Medawar 60 years ago, an amazingly elaborate assortment of molecular and cellular modifications acting both locally at the maternal-placental interface and systemically have been shown to silence potentially detrimental maternal immune responses. In turn, simultaneously maintaining host defense against the infinite array of potential pathogens during pregnancy is equally important. Fortunately, resistance against most infections is preserved seamlessly throughout gestation. On the other hand, recent studies on pathogens with unique predisposition for prenatal infections have uncovered distinctive holes in host defense associated with the reproductive process. Using these infections to probe the response during pregnancy, the immune suppressive regulatory subset of maternal CD4 T cells has been increasingly shown to dictate the inter-workings between prenatal infection susceptibility and pathogenesis of ensuing pregnancy complications. Herein, the recent literature suggesting a necessity for maternal regulatory T cells (Tregs) in pregnancy-induced immunological shifts that sustain fetal tolerance is reviewed. Additional discussion is focused on how expansion of maternal Treg suppression may become exploited by pathogens that cause prenatal infections and the perilous potential of infection-induced immune activation that may mitigate fetal tolerance and inadvertently inject hostility into the protective in utero environment.

  14. Disseminated rhodococcus equi infection in HIV infection despite highly active antiretroviral therapy

    PubMed Central

    2011-01-01

    Background Rhodococcus equi (R.equi) is an acid fast, GRAM + coccobacillus, which is widespread in the soil and causes pulmonary and extrapulmonary infections in immunocompromised people. In the context of HIV infection, R.equi infection (rhodococcosis) is regarded as an opportunistic disease, and its outcome is influenced by highly active antiretroviral therapy (HAART). Case presentation We report two cases of HIV-related rhodococcosis that disseminated despite suppressive HAART and anti-rhodococcal treatment; in both cases there was no immunological recovery, with CD4+ cells count below 200/μL. In the first case, pulmonary rhodococcosis presented 6 months after initiation of HAART, and was followed by an extracerebral intracranial and a cerebral rhodococcal abscess 1 and 8 months, respectively, after onset of pulmonary infection. The second case was characterized by a protracted course with spread of infection to various organs, including subcutaneous tissue, skin, colon and other intra-abdominal tissues, and central nervous system; the spread started 4 years after clinical resolution of a first pulmonary manifestation and progressed over a period of 2 years. Conclusions Our report highlights the importance of an effective immune recovery, despite fully suppressive HAART, along with anti-rhodococcal therapy, in order to clear rhodococcal infection. PMID:22168333

  15. T helper cell activation and human retroviral pathogenesis.

    PubMed Central

    Copeland, K F; Heeney, J L

    1996-01-01

    T helper (Th) cells are of central importance in regulating many critical immune effector mechanisms. The profile of cytokines produced by Th cells correlates with the type of effector cells induced during the immune response to foreign antigen. Th1 cells induce the cell-mediated immune response, while Th2 cells drive antibody production. Th cells are the preferential targets of human retroviruses. Infections with human T-cell leukemia virus (HTLV) or human immunodeficiency virus (HIV) result in the expansion of Th cells by the action of HTLV (adult T-cell leukemia) or the progressive loss of T cells by the action of HIV (AIDS). Both retrovirus infections impart a high-level activation state in the host immune cells as well as systemically. However, diverging responses to this activation state have contrasting effects on the Th-cell population. In HIV infection, Th-cell loss has been attributed to several mechanisms, including a selective elimination of cells by apoptosis. The induction of apoptosis in HIV infection is complex, with many different pathways able to induce cell death. In contrast, infection of Th cells with HTLV-1 affords the cell a protective advantage against apoptosis. This advantage may allow the cell to escape immune surveillance, providing the opportunity for the development of Th-cell cancer. In this review, we will discuss the impact of Th-cell activation and general immune activation on human retrovirus expression with a focus upon Th-cell function and the progression to disease. PMID:8987361

  16. ERas protein is overexpressed and binds to the activated platelet-derived growth factor β receptor in bovine urothelial tumour cells associated with papillomavirus infection.

    PubMed

    Russo, Valeria; Roperto, Franco; Esposito, Iolanda; Ceccarelli, Dora Maria; Zizzo, Nicola; Leonardi, Leonardo; Capparelli, Rosanna; Borzacchiello, Giuseppe; Roperto, Sante

    2016-06-01

    Embryonic stem cell-expressed Ras (ERas) encodes a constitutively active form of guanosine triphosphatase (GTPase) that binds to and activates phosphatidylinositol 3 kinase (PI3K), which in turn phosphorylates and activates downstream targets such as Akt. The current study evaluated ERas regulation and expression in papillomavirus-associated urothelial tumours in cattle grazing on lands rich in bracken fern. ERas was found upregulated and overexpressed by PCR, real time PCR and Western blot. Furthermore, protein overexpression was also confirmed by immunohistochemistry. ERas was found to interact physically and colocalise with the activated platelet derived growth factor β receptor (PDGFβR) by coimmunoprecipitation and laser scanning confocal investigations. Phosphorylation of Akt, a downstream effector both of ERas and PDGFβR, appeared to be increased in urothelial tumour cells. Altogether, these data indicate that ERas/PDGFβR complex could play a role in the pathogenesis of bovine papillomavirus-associated bladder neoplasia. PMID:27256024

  17. Directly Infected Resting CD4+T Cells Can Produce HIV Gag without Spreading Infection in a Model of HIV Latency

    PubMed Central

    Pace, Matthew J.; Graf, Erin H.; Agosto, Luis M.; Mexas, Angela M.; Male, Frances; Brady, Troy; Bushman, Frederic D.; O'Doherty, Una

    2012-01-01

    Despite the effectiveness of highly active antiretroviral therapy (HAART) in treating individuals infected with HIV, HAART is not a cure. A latent reservoir, composed mainly of resting CD4+T cells, drives viral rebound once therapy is stopped. Understanding the formation and maintenance of latently infected cells could provide clues to eradicating this reservoir. However, there have been discrepancies regarding the susceptibility of resting cells to HIV infection in vitro and in vivo. As we have previously shown that resting CD4+T cells are susceptible to HIV integration, we asked whether these cells were capable of producing viral proteins and if so, why resting cells were incapable of supporting productive infection. To answer this question, we spinoculated resting CD4+T cells with or without prior stimulation, and measured integration, transcription, and translation of viral proteins. We found that resting cells were capable of producing HIV Gag without supporting spreading infection. This block corresponded with low HIV envelope levels both at the level of protein and RNA and was not an artifact of spinoculation. The defect was reversed upon stimulation with IL-7 or CD3/28 beads. Thus, a population of latent cells can produce viral proteins without resulting in spreading infection. These results have implications for therapies targeting the latent reservoir and suggest that some latent cells could be cleared by a robust immune response. PMID:22911005

  18. Gelsolin activity controls efficient early HIV-1 infection

    PubMed Central

    2013-01-01

    Background HIV-1 entry into target lymphocytes requires the activity of actin adaptors that stabilize and reorganize cortical F-actin, like moesin and filamin-A. These alterations are necessary for the redistribution of CD4-CXCR4/CCR5 to one pole of the cell, a process that increases the probability of HIV-1 Envelope (Env)-CD4/co-receptor interactions and that generates the tension at the plasma membrane necessary to potentiate fusion pore formation, thereby favouring early HIV-1 infection. However, it remains unclear whether the dynamic processing of F-actin and the amount of cortical actin available during the initial virus-cell contact are required to such events. Results Here we show that gelsolin restructures cortical F-actin during HIV-1 Env-gp120-mediated signalling, without affecting cell-surface expression of receptors or viral co-receptor signalling. Remarkably, efficient HIV-1 Env-mediated membrane fusion and infection of permissive lymphocytes were impaired when gelsolin was either overexpressed or silenced, which led to a loss or gain of cortical actin, respectively. Indeed, HIV-1 Env-gp120-induced F-actin reorganization and viral receptor capping were impaired under these experimental conditions. Moreover, gelsolin knockdown promoted HIV-1 Env-gp120-mediated aberrant pseudopodia formation. These perturbed-actin events are responsible for the inhibition of early HIV-1 infection. Conclusions For the first time we provide evidence that through its severing of cortical actin, and by controlling the amount of actin available for reorganization during HIV-1 Env-mediated viral fusion, entry and infection, gelsolin can constitute a barrier that restricts HIV-1 infection of CD4+ lymphocytes in a pre-fusion step. These findings provide important insights into the complex molecular and actin-associated dynamics events that underlie early viral infection. Thus, we propose that gelsolin is a new factor that can limit HIV-1 infection acting at a pre-fusion step

  19. Roles and relevance of mast cells in infection and vaccination

    PubMed Central

    Fang, Yu; Xiang, Zou

    2016-01-01

    Abstract In addition to their well-established role in allergy mast cells have been described as contributing to functional regulation of both innate and adaptive immune responses in host defense. Mast cells are of hematopoietic origin but typically complete their differentiation in tissues where they express immune regulatory functions by releasing diverse mediators and cytokines. Mast cells are abundant at mucosal tissues which are portals of entry for common infectious agents in addition to allergens. Here, we review the current understanding of the participation of mast cells in defense against infection. We also discuss possibilities of exploiting mast cell activation to provide adequate adjuvant activity that is needed in high-quality vaccination against infectious diseases. PMID:26565602

  20. Evaluation of Functional NK Cell Responses in Vaccinated and SIV-Infected Rhesus Macaques.

    PubMed

    Vargas-Inchaustegui, Diego A; Ying, Olivia; Demberg, Thorsten; Robert-Guroff, Marjorie

    2016-01-01

    NK cells are crucial components of the innate immune system due to their capacity to exert rapid cytotoxic and immunomodulatory function in the absence of prior sensitization. NK cells can become activated by exposure to target cells and/or by cytokines produced by antigen-presenting cells. In this study, we examined the effects of a simian immunodeficiency virus (SIV) vaccine regimen and subsequent SIV infection on the cytotoxic and immunomodulatory functions of circulatory NK cells. While vaccination did not significantly impact the capacity of NK cells to kill MHC-devoid 721.221 target cells, SIV-infection led to a significant decrease in target cell killing. NK cells from uninfected macaques were responsive to a low dose (5 ng/ml) of IL-15 pre-activation, leading to significant increases in their cytotoxic potential, however, NK cells from SIV-infected macaques required a higher dose (50 ng/ml) of IL-15 pre-activation in order to significantly increase their cytotoxic potential. By contrast, no differences were observed in the capacity of NK cells from vaccinated and SIV-infected macaques to respond to IL-12 and IL-18. Similarly, NK cells both before and after infection exhibited equivalent responses to Fc-mediated activation. Collectively, our results show that early SIV-infection impairs the natural cytotoxic capacity of circulatory NK cells without affecting Fc-mediated or cytokine-producing function. PMID:27630641

  1. Evaluation of Functional NK Cell Responses in Vaccinated and SIV-Infected Rhesus Macaques

    PubMed Central

    Vargas-Inchaustegui, Diego A.; Ying, Olivia; Demberg, Thorsten; Robert-Guroff, Marjorie

    2016-01-01

    NK cells are crucial components of the innate immune system due to their capacity to exert rapid cytotoxic and immunomodulatory function in the absence of prior sensitization. NK cells can become activated by exposure to target cells and/or by cytokines produced by antigen-presenting cells. In this study, we examined the effects of a simian immunodeficiency virus (SIV) vaccine regimen and subsequent SIV infection on the cytotoxic and immunomodulatory functions of circulatory NK cells. While vaccination did not significantly impact the capacity of NK cells to kill MHC-devoid 721.221 target cells, SIV-infection led to a significant decrease in target cell killing. NK cells from uninfected macaques were responsive to a low dose (5 ng/ml) of IL-15 pre-activation, leading to significant increases in their cytotoxic potential, however, NK cells from SIV-infected macaques required a higher dose (50 ng/ml) of IL-15 pre-activation in order to significantly increase their cytotoxic potential. By contrast, no differences were observed in the capacity of NK cells from vaccinated and SIV-infected macaques to respond to IL-12 and IL-18. Similarly, NK cells both before and after infection exhibited equivalent responses to Fc-mediated activation. Collectively, our results show that early SIV-infection impairs the natural cytotoxic capacity of circulatory NK cells without affecting Fc-mediated or cytokine-producing function.

  2. Evaluation of Functional NK Cell Responses in Vaccinated and SIV-Infected Rhesus Macaques

    PubMed Central

    Vargas-Inchaustegui, Diego A.; Ying, Olivia; Demberg, Thorsten; Robert-Guroff, Marjorie

    2016-01-01

    NK cells are crucial components of the innate immune system due to their capacity to exert rapid cytotoxic and immunomodulatory function in the absence of prior sensitization. NK cells can become activated by exposure to target cells and/or by cytokines produced by antigen-presenting cells. In this study, we examined the effects of a simian immunodeficiency virus (SIV) vaccine regimen and subsequent SIV infection on the cytotoxic and immunomodulatory functions of circulatory NK cells. While vaccination did not significantly impact the capacity of NK cells to kill MHC-devoid 721.221 target cells, SIV-infection led to a significant decrease in target cell killing. NK cells from uninfected macaques were responsive to a low dose (5 ng/ml) of IL-15 pre-activation, leading to significant increases in their cytotoxic potential, however, NK cells from SIV-infected macaques required a higher dose (50 ng/ml) of IL-15 pre-activation in order to significantly increase their cytotoxic potential. By contrast, no differences were observed in the capacity of NK cells from vaccinated and SIV-infected macaques to respond to IL-12 and IL-18. Similarly, NK cells both before and after infection exhibited equivalent responses to Fc-mediated activation. Collectively, our results show that early SIV-infection impairs the natural cytotoxic capacity of circulatory NK cells without affecting Fc-mediated or cytokine-producing function. PMID:27630641

  3. Parasitic Infections in Hematopoietic Stem Cell Transplantation.

    PubMed

    Jarque, Isidro; Salavert, Miguel; Pemán, Javier

    2016-01-01

    Parasitic infections are rarely documented in hematopoietic stem cell transplant recipients. However they may be responsible for fatal complications that are only diagnosed at autopsy. Increased awareness of the possibility of parasitic diseases both in autologous and allogeneic stem cell transplant patients is relevant not only for implementing preventive measures but also for performing an early diagnosis and starting appropriate therapy for these unrecognized but fatal infectious complications in hematopoietic transplant recipients. In this review, we will focus on parasitic diseases occurring in this population especially those with major clinical relevance including toxoplasmosis, American trypanosomiasis, leishmaniasis, malaria, and strongyloidiasis, among others, highlighting the diagnosis and management in hematopoietic transplant recipients. PMID:27413527

  4. Parasitic Infections in Hematopoietic Stem Cell Transplantation

    PubMed Central

    Jarque, Isidro; Salavert, Miguel; Pemán, Javier

    2016-01-01

    Parasitic infections are rarely documented in hematopoietic stem cell transplant recipients. However they may be responsible for fatal complications that are only diagnosed at autopsy. Increased awareness of the possibility of parasitic diseases both in autologous and allogeneic stem cell transplant patients is relevant not only for implementing preventive measures but also for performing an early diagnosis and starting appropriate therapy for these unrecognized but fatal infectious complications in hematopoietic transplant recipients. In this review, we will focus on parasitic diseases occurring in this population especially those with major clinical relevance including toxoplasmosis, American trypanosomiasis, leishmaniasis, malaria, and strongyloidiasis, among others, highlighting the diagnosis and management in hematopoietic transplant recipients. PMID:27413527

  5. Target Cell Cyclophilins Facilitate Human Papillomavirus Type 16 Infection

    PubMed Central

    Sapp, Martin

    2009-01-01

    Following attachment to primary receptor heparan sulfate proteoglycans (HSPG), human papillomavirus type 16 (HPV16) particles undergo conformational changes affecting the major and minor capsid proteins, L1 and L2, respectively. This results in exposure of the L2 N-terminus, transfer to uptake receptors, and infectious internalization. Here, we report that target cell cyclophilins, peptidyl-prolyl cis/trans isomerases, are required for efficient HPV16 infection. Cell surface cyclophilin B (CyPB) facilitates conformational changes in capsid proteins, resulting in exposure of the L2 N-terminus. Inhibition of CyPB blocked HPV16 infection by inducing noninfectious internalization. Mutation of a putative CyP binding site present in HPV16 L2 yielded exposed L2 N-terminus in the absence of active CyP and bypassed the need for cell surface CyPB. However, this mutant was still sensitive to CyP inhibition and required CyP for completion of infection, probably after internalization. Taken together, these data suggest that CyP is required during two distinct steps of HPV16 infection. Identification of cell surface CyPB will facilitate the study of the complex events preceding internalization and adds a putative drug target for prevention of HPV–induced diseases. PMID:19629175

  6. Hospital infection control in hematopoietic stem cell transplant recipients.

    PubMed Central

    Dykewicz, C. A.

    2001-01-01

    Guidelines for Preventing Opportunistic Infections Among Hematopoietic Stem Cell Transplant Recipients contains a section on hospital infection control including evidence-based recommendations regarding ventilation, construction, equipment, plants, play areas and toys, health-care workers, visitors, patient skin and oral care, catheter-related infections, drug-resistant organisms, and specific nosocomial infections. These guidelines are intended to reduce the number and severity of hospital infections in hematopoietic stem cell transplant recipients. PMID:11294720

  7. Comparative antibiotic eradication of mycoplasma infections from continuous cell lines.

    PubMed

    Uphoff, Cord C; Drexler, Hans G

    2002-02-01

    Accumulating data implicate mycoplasma contamination as the single biggest problem in the culture of continuous cell lines. Mycoplasma infection can affect virtually every parameter and functional activity of the eukaryotic cells. A successful alternative to discarding infected cultures is to attempt to eliminate the contaminants by treatment with specific and efficient antimycoplasma antibiotics. The addition of antibiotics to the culture medium during a limited period of time (1-3 wk) is a simple, inexpensive, and very practical approach for decontaminating continuous cell lines. Here, we examined the effectiveness of several antibiotic treatment protocols that we have employed routinely in our cell lines bank. On an aggregate, 673 cultures from 236 chronically mycoplasma-positive cell lines were exposed to one of the following five antibiotic regimens: mycoplasma removal agent (quinolone; a 1-wk treatment), enrofloxacin (quinolone; 1 wk), sparfloxacin (quinolone; 1 wk), ciprofloxacin (quinolone; 2 wk), and BM-Cyclin (alternating tiamulin and minocycline; 3 wk). The mycoplasma infection was permanently (as determined by three solid mycoplasma detection assays) eliminated by the various antibiotics in 66-85% of the cultures treated. Mycoplasma resistance was seen in 7-21%, and loss of the culture as a result of cytotoxically caused cell death occurred in 3-11% of the cultures treated. Overall, 223 of the 236 mycoplasma-positive cell lines could be cured in a first round of antibiotic treatment with at least one regimen. Taken together, 95% of the mycoplasma-infected cell lines were permanently cleansed of the contaminants by antibiotic treatment, which validates this approach as an efficient and technically simple mycoplasma eradication method.

  8. Comparative antibiotic eradication of mycoplasma infections from continuous cell lines.

    PubMed

    Uphoff, Cord C; Drexler, Hans G

    2002-02-01

    Accumulating data implicate mycoplasma contamination as the single biggest problem in the culture of continuous cell lines. Mycoplasma infection can affect virtually every parameter and functional activity of the eukaryotic cells. A successful alternative to discarding infected cultures is to attempt to eliminate the contaminants by treatment with specific and efficient antimycoplasma antibiotics. The addition of antibiotics to the culture medium during a limited period of time (1-3 wk) is a simple, inexpensive, and very practical approach for decontaminating continuous cell lines. Here, we examined the effectiveness of several antibiotic treatment protocols that we have employed routinely in our cell lines bank. On an aggregate, 673 cultures from 236 chronically mycoplasma-positive cell lines were exposed to one of the following five antibiotic regimens: mycoplasma removal agent (quinolone; a 1-wk treatment), enrofloxacin (quinolone; 1 wk), sparfloxacin (quinolone; 1 wk), ciprofloxacin (quinolone; 2 wk), and BM-Cyclin (alternating tiamulin and minocycline; 3 wk). The mycoplasma infection was permanently (as determined by three solid mycoplasma detection assays) eliminated by the various antibiotics in 66-85% of the cultures treated. Mycoplasma resistance was seen in 7-21%, and loss of the culture as a result of cytotoxically caused cell death occurred in 3-11% of the cultures treated. Overall, 223 of the 236 mycoplasma-positive cell lines could be cured in a first round of antibiotic treatment with at least one regimen. Taken together, 95% of the mycoplasma-infected cell lines were permanently cleansed of the contaminants by antibiotic treatment, which validates this approach as an efficient and technically simple mycoplasma eradication method. PMID:11929000

  9. Association of alpha interferon production with natural killer cell lysis of U937 cells infected with human immunodeficiency virus.

    PubMed Central

    Rappocciolo, G; Toso, J F; Torpey, D J; Gupta, P; Rinaldo, C R

    1989-01-01

    Mononuclear leukocytes from human immunodeficiency virus (HIV)-seronegative and -seropositive homosexual men lysed HIV-infected U937 cells to a significantly greater degree than uninfected U937 cells. Depletion of cell subsets with monoclonal antibodies and complement indicated that the effector cells were primarily of the CD16+ phenotype. Acid-stable alpha interferon (IFN-alpha) production induced by the HIV-infected cells correlated with, although was not an absolute requisite for, preferential lysis of the infected targets. The activity of these CD16+, natural killer (NK) cells decreased in relation to the duration of HIV infection and the presence of acquired immunodeficiency syndrome. Pretreatment of peripheral blood mononuclear cells from HIV-seronegative subjects, but not HIV-seropositive men, with IFN-alpha or recombinant interleukin-2 enhanced lysis of both uninfected and HIV-infected U937 cells. These results suggest that IFN-alpha-associated, NK-like mechanisms are active in the cytotoxic response against HIV-infected cells and that HIV infection results in an early and progressive depression of such responses. Prospective investigations may be useful in determining the role of this NK cell response in the natural history and pathogenesis of HIV infection and the efficacy of therapeutic modalities. PMID:2913035

  10. Alterations in T Cell Subsets in Human Immunodeficiency Virus–Infected Adults with Co-infections in Southern Mozambique

    PubMed Central

    Naniche, Denise; Letang, Emilio; Nhampossa, Tacilta; David, Catarina; Menendez, Clara; Alonso, Pedro

    2011-01-01

    T cell activation and depletion of naive T cells are hallmarks of human immunodeficiency virus (HIV) pathogenesis. This study explored the relationships between certain co-infections (including syphilis, hepatitis B and C, human T cell lymphotrophic viruses I and II [HTLV-I/II], Kaposi sarcoma–associated herpesvirus [KSHV], Plasmodium falciparum malaria, and tuberculosis), and levels of activated CD8 and CD4 T cell subsets as well as naive and memory CD4 T cells in HIV-infected adults in a rural area of southern Mozambique. We found that syphilis infection and to a lesser extent HTLV-I/II seropositivity were independently associated with higher CD8 T cell activation (CD8+ CD38+ HLA-DR+) whereas only syphilis was associated with higher CD4 T cell activation. Furthermore, KSHV and HTLV-I/II seropositivities were independently associated with a lower percentage of naive CD4 T cells (CD4+ CD45RA+ CD62L+). These results highlight the importance of screening and prompt treatment of syphilis, and raise questions as to whether HIV-positive persons with certain chronic viral co-infections should initiate combined antiretroviral therapy at higher CD4 cell counts. PMID:21976586

  11. Human dendritic cells as targets of dengue virus infection.

    PubMed

    Marovich, M; Grouard-Vogel, G; Louder, M; Eller, M; Sun, W; Wu, S J; Putvatana, R; Murphy, G; Tassaneetrithep, B; Burgess, T; Birx, D; Hayes, C; Schlesinger-Frankel, S; Mascola, J

    2001-12-01

    Dengue virus infections are an emerging global threat. Severe dengue infection is manifested as dengue hemorrhagic fever and dengue shock syndrome, both of which can be fatal complications. Factors predisposing to complicated disease and pathogenesis of severe infections are discussed. Using immunohistochemistry, immunofluorescence, flow cytometry, and ELISA techniques, we studied the cellular targets of dengue virus infection, at both the clinical (in vivo) and the laboratory (in vitro) level. Resident skin dendritic cells are targets of dengue virus infection as demonstrated in a skin biopsy from a dengue vaccine recipient. We show that factors influencing infection of monocytes/macrophages and dendritic cells are different. Immature dendritic cells were found to be the cells most permissive for dengue infection and maybe early targets for infection. Immature dendritic cells exposed to dengue virus produce TNF-alpha protein. Some of these immature dendritic cells undergo TNF-alpha mediated maturation as a consequence of exposure to the dengue virus. PMID:11924831

  12. α-Lipoic Acid Inhibits Expression of IL-8 by Suppressing Activation of MAPK, Jak/Stat, and NF-κB in H. pylori-Infected Gastric Epithelial AGS Cells.

    PubMed

    Choi, Ji Hyun; Cho, Soon Ok; Kim, Hyeyoung

    2016-01-01

    The epithelial cytokine response, associated with reactive oxygen species (ROS), is important in Helicobacter pylori (H. pylori)-induced inflammation. H. pylori induces the production of ROS, which may be involved in the activation of mitogen-activated protein kinases (MAPK), janus kinase/signal transducers and activators of transcription (Jak/Stat), and oxidant-sensitive transcription factor, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and thus, expression of interleukin-8 (IL-8) in gastric epithelial cells. α-lipoic acid, a naturally occurring thiol compound, is a potential antioxidant. It shows beneficial effects in treatment of oxidant-associated diseases including diabetes. The present study is purposed to investigate whether α-lipoic acid inhibits expression of inflammatory cytokine IL-8 by suppressing activation of MAPK, Jak/Stat, and NF-κB in H. pylori-infected gastric epithelial cells. Gastric epithelial AGS cells were pretreated with or without α-lipoic acid for 2 h and infected with H. pylori in a Korean isolate (HP99) at a ratio of 300:1. IL-8 mRNA expression was analyzed by RT-PCR analysis. IL-8 levels in the medium were determined by enzyme-linked immunosorbent assay. NF-κB-DNA binding activity was determined by electrophoretic mobility shift assay. Phospho-specific and total forms of MAPK and Jak/Stat were assessed by Western blot analysis. ROS levels were determined using dichlorofluorescein fluorescence. As a result, H. pylori induced increases in ROS levels, mRNA, and protein levels of IL-8, as well as the activation of MAPK [extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun NH2-terminal kinase 1/2 (JNK1/2), p38], Jak/Stat (Jak1/2, Stat3), and NF-κB in AGS cells, which was inhibited by α-lipoic acid. In conclusion, α-lipoic acid may be beneficial for prevention and/or treatment of H. pylori infection-associated gastric inflammation.

  13. α-Lipoic Acid Inhibits Expression of IL-8 by Suppressing Activation of MAPK, Jak/Stat, and NF-κB in H. pylori-Infected Gastric Epithelial AGS Cells

    PubMed Central

    Choi, Ji Hyun; Cho, Soon Ok

    2016-01-01

    The epithelial cytokine response, associated with reactive oxygen species (ROS), is important in Helicobacter pylori (H. pylori)-induced inflammation. H. pylori induces the production of ROS, which may be involved in the activation of mitogen-activated protein kinases (MAPK), janus kinase/signal transducers and activators of transcription (Jak/Stat), and oxidant-sensitive transcription factor, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and thus, expression of interleukin-8 (IL-8) in gastric epithelial cells. α-lipoic acid, a naturally occurring thiol compound, is a potential antioxidant. It shows beneficial effects in treatment of oxidant-associated diseases including diabetes. The present study is purposed to investigate whether α-lipoic acid inhibits expression of inflammatory cytokine IL-8 by suppressing activation of MAPK, Jak/Stat, and NF-κB in H. pylori-infected gastric epithelial cells. Gastric epithelial AGS cells were pretreated with or without α-lipoic acid for 2 h and infected with H. pylori in a Korean isolate (HP99) at a ratio of 300:1. IL-8 mRNA expression was analyzed by RT-PCR analysis. IL-8 levels in the medium were determined by enzyme-linked immunosorbent assay. NF-κB-DNA binding activity was determined by electrophoretic mobility shift assay. Phospho-specific and total forms of MAPK and Jak/Stat were assessed by Western blot analysis. ROS levels were determined using dichlorofluorescein fluorescence. As a result, H. pylori induced increases in ROS levels, mRNA, and protein levels of IL-8, as well as the activation of MAPK [extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun NH2-terminal kinase 1/2 (JNK1/2), p38], Jak/Stat (Jak1/2, Stat3), and NF-κB in AGS cells, which was inhibited by α-lipoic acid. In conclusion, α-lipoic acid may be beneficial for prevention and/or treatment of H. pylori infection-associated gastric inflammation. PMID:26632410

  14. Infection of XC cells by MLVs and Ebola virus is endosome-dependent but acidification-independent.

    PubMed

    Kamiyama, Haruka; Kakoki, Katsura; Yoshii, Hiroaki; Iwao, Masatomo; Igawa, Tsukasa; Sakai, Hideki; Hayashi, Hideki; Matsuyama, Toshifumi; Yamamoto, Naoki; Kubo, Yoshinao

    2011-01-01

    Inhibitors of endosome acidification or cathepsin proteases attenuated infections mediated by envelope proteins of xenotropic murine leukemia virus-related virus (XMRV) and Ebola virus, as well as ecotropic, amphotropic, polytropic, and xenotropic murine leukemia viruses (MLVs), indicating that infections by these viruses occur through acidic endosomes and require cathepsin proteases in the susceptible cells such as TE671 cells. However, as previously shown, the endosome acidification inhibitors did not inhibit these viral infections in XC cells. It is generally accepted that the ecotropic MLV infection in XC cells occurs at the plasma membrane. Because cathepsin proteases are activated by low pH in acidic endosomes, the acidification inhibitors may inhibit the viral infections by suppressing cathepsin protease activation. The acidification inhibitors attenuated the activities of cathepsin proteases B and L in TE671 cells, but not in XC cells. Processing of cathepsin protease L was suppressed by the acidification inhibitor in NIH3T3 cells, but again not in XC cells. These results indicate that cathepsin proteases are activated without endosome acidification in XC cells. Treatment with an endocytosis inhibitor or knockdown of dynamin 2 expression by siRNAs suppressed MLV infections in all examined cells including XC cells. Furthermore, endosomal cathepsin proteases were required for these viral infections in XC cells as other susceptible cells. These results suggest that infections of XC cells by the MLVs and Ebola virus occur through endosomes and pH-independent cathepsin activation induces pH-independent infection in XC cells.

  15. Universal cytotoxic activity of a HTLV-1 Tax-specific T cell clone from an HLA-A*24:02⁺ patient with adult T-cell leukemia against a variety of HTLV-I-infected T-cells.

    PubMed

    Tanaka, Yukie; Yamazaki, Rie; Terasako-Saito, Kiriko; Nakasone, Hideki; Akahoshi, Yu; Nakano, Hirofumi; Ugai, Tomotaka; Wada, Hidenori; Yamasaki, Ryoko; Ishihara, Yuko; Kawamura, Koji; Sakamoto, Kana; Ashizawa, Masahiro; Sato, Miki; Kimura, Shun-ichi; Kikuchi, Misato; Kako, Shinichi; Kanda, Junya; Tanihara, Aki; Nishida, Junji; Kanda, Yoshinobu

    2014-01-01

    Adult T cell leukemia/lymphoma (ATL) is an aggressive mature T cell malignancy that is causally associated with human T cell lymphotropic virus type 1 (HTLV-1) infection. The HTLV-1 regulatory protein Tax aggressively accelerates the proliferation of host cells and is also an important target antigen for CD8(+) cytotoxic T cells (CTLs). We previously reported that several predominant HLA-A*24:02-restricted HTLV-1 Tax301-309-specific CTL clones commonly expressed a particular amino acid sequence motif (P-D-R) in complementarity-determining region 3 of T-cell receptor (TCR)-β chain among unrelated ATL patients who underwent allogeneic stem cell transplantation (allo-HSCT). Furthermore, a PDR-motif(+) CTL clone persistently existed in a long-term survivor as a central CTL clone with strong CTL activities after HSCT. Although a larger analysis of the relationship between PDR-motif(+) CTLs and the clinical course is required, the expression of PDR-motif(+) TCR on CD8(+) T cells may play a critical role in the management of anti-HTLV-1 activities for HLA-A24:02(+) ATL patients. Therefore, in this study, we prepared an HTLV-1 Tax301-309 peptide-specific CTL clone (HT-9) expressing PDR-motif(+) TCR isolated from a long-term survivor after HSCT, and evaluated its CTL activity against a variety of HTLV-1-infected T-cells from HLA-A*24:02(+) ATL patients. Before the assay of CTL function, we confirmed that HT-9 expressed less-differentiated effector-memory phenotypes (CD45RA(-)CCR7(-)CD27(+)CD28(+/-)CD57(+/-)) and T-cell exhaustion marker PD-1(+). In assays of CTL function, HT-9 recognized HTLV-1 Tax in an HLA-restricted fashion and demonstrated strong CTL activities against a variety of HTLV-1-infected T-cells from HLA-A*24:02(+) ATL patients regardless of whether the sources were autologous or allogeneic, but not normal cells. These data indicate that PDR-motif(+) TCR could be an important TCR candidate for TCR-gene immunotherapy for HLA-A24:02(+) ATL patients, provided

  16. Elimination of HIV-1-infected cells by broadly neutralizing antibodies.

    PubMed

    Bruel, Timothée; Guivel-Benhassine, Florence; Amraoui, Sonia; Malbec, Marine; Richard, Léa; Bourdic, Katia; Donahue, Daniel Aaron; Lorin, Valérie; Casartelli, Nicoletta; Noël, Nicolas; Lambotte, Olivier; Mouquet, Hugo; Schwartz, Olivier

    2016-01-01

    The Fc region of HIV-1 Env-specific broadly neutralizing antibodies (bNAbs) is required for suppressing viraemia, through mechanisms which remain poorly understood. Here, we identify bNAbs that exert antibody-dependent cellular cytotoxicity (ADCC) in cell culture and kill HIV-1-infected lymphocytes through natural killer (NK) engagement. These antibodies target the CD4-binding site, the glycans/V3 and V1/V2 loops on gp120, or the gp41 moiety. The landscape of Env epitope exposure at the surface and the sensitivity of infected cells to ADCC vary considerably between viral strains. Efficient ADCC requires sustained cell surface binding of bNAbs to Env, and combining bNAbs allows a potent killing activity. Furthermore, reactivated infected cells from HIV-positive individuals expose heterogeneous Env epitope patterns, with levels that are often but not always sufficient to trigger killing by bNAbs. Our study delineates the parameters controlling ADCC activity of bNAbs, and supports the use of the most potent antibodies to clear the viral reservoir. PMID:26936020

  17. Elimination of HIV-1-infected cells by broadly neutralizing antibodies

    PubMed Central

    Bruel, Timothée; Guivel-Benhassine, Florence; Amraoui, Sonia; Malbec, Marine; Richard, Léa; Bourdic, Katia; Donahue, Daniel Aaron; Lorin, Valérie; Casartelli, Nicoletta; Noël, Nicolas; Lambotte, Olivier; Mouquet, Hugo; Schwartz, Olivier

    2016-01-01

    The Fc region of HIV-1 Env-specific broadly neutralizing antibodies (bNAbs) is required for suppressing viraemia, through mechanisms which remain poorly understood. Here, we identify bNAbs that exert antibody-dependent cellular cytotoxicity (ADCC) in cell culture and kill HIV-1-infected lymphocytes through natural killer (NK) engagement. These antibodies target the CD4-binding site, the glycans/V3 and V1/V2 loops on gp120, or the gp41 moiety. The landscape of Env epitope exposure at the surface and the sensitivity of infected cells to ADCC vary considerably between viral strains. Efficient ADCC requires sustained cell surface binding of bNAbs to Env, and combining bNAbs allows a potent killing activity. Furthermore, reactivated infected cells from HIV-positive individuals expose heterogeneous Env epitope patterns, with levels that are often but not always sufficient to trigger killing by bNAbs. Our study delineates the parameters controlling ADCC activity of bNAbs, and supports the use of the most potent antibodies to clear the viral reservoir. PMID:26936020

  18. Follicular dendritic cells and human immunodeficiency virus infectivity

    NASA Astrophysics Data System (ADS)

    Heath, Sonya L.; Tew, J. Grant; Tew, John G.; Szakal, Andras K.; Burton, Gregory F.

    1995-10-01

    LARGE amounts of human immunodeficiency virus (HIV) localize on follicular dendritic cells (FDC) in the follicles of secondary lymphoid tissues following viral infection1,2. During clinical latency, active viral infection occurs primarily at these sites3,4. As HIV on FDC is in the form of immune complexes5, some of which may be formed with neutralizing antibody, we investigated whether HIV on FDC is infectious. We report here that HIV on FDC is highly infectious. Furthermore, FDC can convert neutralized HIV into an infectious form even in the presence of a vast excess of neutralizing antibody. Thus FDC may provide a mechanism whereby HIV infection can continue in the presence of neutralizing antibody.

  19. Changed iron regulation in scrapie-infected neuroblastoma cells.

    PubMed

    Fernaeus, Sandra; Hälldin, Jonas; Bedecs, Katarina; Land, Tiit

    2005-02-18

    Prion diseases are characterized by the conversion of the normal cellular prion protein PrP(C) into a pathogenic isoform, PrP(Sc). The mechanisms involved in neuronal cell death in prion diseases are largely unknown, but accumulating evidence has demonstrated oxidative impairment along with metal imbalances in scrapie-infected brains. In this study, we report changes in cellular iron metabolism in scrapie-infected mouse neuroblastoma N2a cells (ScN2a). We detected twofold lower total cellular iron and calcein-chelatable cytosolic labile iron pool (LIP) in ScN2a cells as compared to the N2a cells. We also measured in ScN2a cells significantly lower activities of iron regulatory proteins 1 and 2 (IRP1 and IRP2, respectively), regulators of cellular iron by sensing cytosolic free iron levels and controlling posttranscriptionally the expression of the major iron transport protein transferrin receptor 1 (TfR1) and the iron sequestration protein ferritin. IRP1 and IRP2 protein levels were decreased by 40% and 50%, respectively, in ScN2a cells. TfR1 protein levels were fourfold reduced and ferritin levels were threefold reduced in ScN2a cells. TfR1 and ferritin mRNA levels were significantly reduced in ScN2a cells. ScN2a cells responded normally to iron and iron chelator treatment with respect to the activities of IRP1 and IRP2, and biosynthesis of TfR1 and ferritin. However, the activities of IRP1 and IRP2, and protein levels of TfR1 and ferritin, were still significantly lower in iron-depleted ScN2a cells as compared to the N2a cells, suggesting lower need for iron in ScN2a cells. Our results demonstrate that scrapie infection leads to changes in cellular iron metabolism, affecting both total cellular and cytosolic free iron, and the activities and expression of major regulators of cellular iron homeostasis. PMID:15710243

  20. Efficient Infection of a Human B Cell Line with Cell-Free Kaposi's Sarcoma-Associated Herpesvirus

    PubMed Central

    Dollery, Stephen J.; Santiago-Crespo, Rey J.; Kardava, Lela; Moir, Susan

    2014-01-01

    ABSTRACT Kaposi's sarcoma-associated herpesvirus (KSHV) is causatively linked to two B cell lymphoproliferative disorders, multicentric Castleman's disease and primary effusion lymphoma. Latently infected B cells are a major KSHV reservoir, and virus activation from tonsillar B cells can result in salivary shedding and virus transmission. Paradoxically, human B cells (primary and continuous) are notoriously refractory to infection, thus posing a major obstacle to the study of KSHV in this cell type. By performing a strategic search of human B cell lymphoma lines, we found that MC116 cells were efficiently infected by cell-free KSHV. Upon exposure to recombinant KSHV.219, enhanced green fluorescent protein reporter expression was detected in 17 to 20% of MC116 cells. Latent-phase transcription and protein synthesis were detected by reverse transcription-PCR and detection of latency-associated nuclear antigen expression, respectively, in cell lysates and individual cells. Selection based on the puromycin resistance gene in KSHV.219 yielded cultures with all cells infected. After repeated passaging of the selected KSHV-infected cells without puromycin, latent KSHV was maintained in a small fraction of cells. Infected MC116 cells could be induced into lytic phase with histone deacetylase inhibitors, as is known for latently infected non-B cell lines, and also selectively by the B cell-specific pathway involving B cell receptor cross-linking. Lytic-phase transition was documented by red fluorescent protein reporter expression, late structural glycoprotein (K8.1A, gH) detection, and infectious KSHV production. MC116 cells were CD27−/CD10+, characteristic of transitional B cells. These findings represent an important step in the establishment of an efficient continuous B cell line model to study the biologically relevant steps of KSHV infection. IMPORTANCE PMID:24257608

  1. Trypsin activation pathway of rotavirus infectivity.

    PubMed Central

    Arias, C F; Romero, P; Alvarez, V; López, S

    1996-01-01

    The infectivity of rotaviruses is increased by and most probably is dependent on trypsin treatment of the virus. This proteolytic treatment specifically cleaves VP4, the protein that forms the spikes on the surface of the virions, to polypeptides VP5 and VP8. This cleavage has been reported to occur in rotavirus SA114fM at two conserved, closely spaced arginine residues located at VP4 amino acids 241 and 247. In this work, we have characterized the VP4 cleavage products of rotavirus SA114S generated by in vitro treatment of the virus with increasing concentrations of trypsin and with proteases AspN and alpha-chymotrypsin. The VP8 and VP5 polypeptides were analyzed by gel electrophoresis and by Western blotting (immunoblotting) with antibodies raised to synthetic peptides that mimic the terminal regions of VP4 generated by the trypsin cleavage. It was shown that in addition to arginine residues 241 and 247, VP4 is cleaved at arginine residue 231. These three sites were found to have different susceptibilities to trypsin, Arg-241 > Arg-231 > Arg-247, with the enhancement of infectivity correlating with cleavage at Arg-247 rather than at Arg-231 or Arg-241. Proteases AspN and alpha-chymotrypsin cleaved VP4 at Asp-242 and Tyr-246, respectively, with no significant enhancement of infectivity, although this enhancement could be achieved by further treatment of the virus with trypsin. The VP4 end products of trypsin treatment were a homogeneous VP8 polypeptide comprising VP4 amino acids 1 to 231 and a heterogeneous VP5, which is formed by two polypeptide species (present at a ratio of approximately 1:5) as a result of cleavage at either Arg-241 or Arg-247. A pathway for the trypsin activation of rotavirus infectivity is proposed. PMID:8709201

  2. Cellulose Acetate 1,2-Benzenedicarboxylate Inhibits Infection by Cell-Free and Cell-Associated Primary HIV-1 Isolates

    PubMed Central

    LU, HONG; ZHAO, QIAN; WALLACE, GREG; LIU, SHUWEN; HE, YUXIAN; SHATTOCK, ROBIN; NEURATH, A. ROBERT; JIANG, SHIBO

    2009-01-01

    Cellulose acetate 1,2-benzenedicarboxylate (CAP), a pharmaceutical excipient used for enteric film coating of capsules and tablets, was previously shown to have potent inhibitory activity against infection by human immunodeficiency virus type 1 (HIV-1) T cell line-adapted (TCLA) strains. In the present study, we determined the inhibitory activity of CAP against infection by cell-free and cell-associated primary HIV-1 isolates with distinct genotypes and biotypes in cervical explants, peripheral blood mononuclear cells (PBMCs), monocyte-derived macrophages (MDMs), and CEMx174 5.25M7 cells. CAP blocked infection by cell-free and cell-associated HIV-1 in cervical explants. It inhibited infection by cell-free primary HIV-1 isolates (clades A to G and group O) in PBMCs, MDMs, and CEMx174 5.25M7 cells and blocked transmissions of the cell-associated primary HIV-1 isolates from dendritic cells (DCs) to PBMCs, from MDMs to PBMCs, and from PBMCs to CEMx174 5.25M7 cells. The inhibitory activity of CAP on infection by the cell-free and cell-associated primary HIV-1 isolates is independent of viral subtypes and coreceptor usage. These data suggest that CAP is a good microbicide candidate that can be further developed for preventing sexual transmission of HIV-1. PMID:16706617

  3. Interferon Response in Hepatitis C Virus (HCV) Infection: Lessons from Cell Culture Systems of HCV Infection.

    PubMed

    Sung, Pil Soo; Shin, Eui-Cheol; Yoon, Seung Kew

    2015-01-01

    Hepatitis C virus (HCV) is a positive-stranded RNA virus that infects approximately 130-170 million people worldwide. In 2005, the first HCV infection system in cell culture was established using clone JFH-1, which was isolated from a Japanese patient with fulminant HCV infection. JFH-1 replicates efficiently in hepatoma cells and infectious virion particles are released into the culture supernatant. The development of cell culture-derived HCV (HCVcc) systems has allowed us to understand how hosts respond to HCV infection and how HCV evades host responses. Although the mechanisms underlying the different outcomes of HCV infection are not fully understood, innate immune responses seem to have a critical impact on the outcome of HCV infection, as demonstrated by the prognostic value of IFN-λ gene polymorphisms among patients with chronic HCV infection. Herein, we review recent research on interferon response in HCV infection, particularly studies using HCVcc infection systems.

  4. Parvovirus Infection Suppresses Long-Term Repopulating Hematopoietic Stem Cells

    PubMed Central

    Segovia, José C.; Guenechea, Guillermo; Gallego, Jesús M.; Almendral, José M.; Bueren, Juan A.

    2003-01-01

    The functional disturbance of self-renewing and multipotent hematopoietic stem cells (HSCs) in viral diseases is poorly understood. In this report, we have assessed the susceptibility of mouse HSCs to strain i of the autonomous parvovirus minute virus of mice (MVMi) in vitro and during persistent infection of an immunodeficient host. Purified 5FUr Lin− Sca-1+ primitive hematopoietic precursors were permissive for MVMi genome replication and the expression of viral gene products. The lymphoid and myeloid repopulating capacity of bone marrow (BM) cells was significantly impaired after in vitro infection, although the degree of functional effect proportionally decreased with the posttransplantation time. This indicated that MVMi targets the heterogeneous compartment of repopulating cells with differential affinity and suggests that the virus may persist in some primitive HSCs in the quiescent stage, killing those eventually recruited for proliferative activity. Immunodeficient SCID mice oronasally infected with MVMi were cured of the characteristic virus-induced lethal leukopenia by transplantation of immunocompetent BM grafts. However, two double-stranded viral DNA species, probably uncommon replicative intermediates, remained in the marrow of every transplanted mouse months after infectious virus clearance. Genetic analysis of the rescued mice showed that the infection ensured a stable engraftment of donor hematopoiesis by markedly depleting the pool of endogenous HSCs. The MVMi-induced suppression of HSC functions illustrates the accessibility of this compartment to infection during a natural viral hematological disease. These results may provide clues to understanding delayed hematopoietic syndromes associated with persistent viral infections and to prospective gene delivery to HSCs in vivo. PMID:12857918

  5. CD8+ T Cells in Leishmania Infections: Friends or Foes?

    PubMed Central

    Stäger, Simona; Rafati, Sima

    2012-01-01

    Host protection against several intracellular pathogens requires the induction of CD8+ T cell responses. CD8+ T cells are potent effector cells that can produce high amounts of pro-inflammatory cytokines and kill infected target cells efficiently. However, a protective role for CD8+ T cells during Leishmania infections is still controversial and largely depends on the infection model. In this review, we discuss the role of CD8+ T cells during various types of Leishmania infections, following vaccination, and as potential immunotherapeutic targets. PMID:22566891

  6. Cell-mediated Protection in Influenza Infection

    PubMed Central

    Thomas, Paul G.; Keating, Rachael; Hulse-Post, Diane J.

    2006-01-01

    Current vaccine strategies against influenza focus on generating robust antibody responses. Because of the high degree of antigenic drift among circulating influenza strains over the course of a year, vaccine strains must be reformulated specifically for each influenza season. The time delay from isolating the pandemic strain to large-scale vaccine production would be detrimental in a pandemic situation. A vaccine approach based on cell-mediated immunity that avoids some of these drawbacks is discussed here. Specifically, cell-mediated responses typically focus on peptides from internal influenza proteins, which are far less susceptible to antigenic variation. We review the literature on the role of CD4+ and CD8+ T cell–mediated immunity in influenza infection and the available data on the role of these responses in protection from highly pathogenic influenza infection. We discuss the advantages of developing a vaccine based on cell-mediated immune responses toward highly pathogenic influenza virus and potential problems arising from immune pressure. PMID:16494717

  7. Nanotechnology as a New Therapeutic Approach to Prevent the HIV-Infection of Treg Cells

    PubMed Central

    Jaramillo-Ruiz, Didiana; De La Mata, Francisco Javier; Gómez, Rafael; Correa-Rocha, Rafael; Muñoz-Fernández, Mª Ángeles

    2016-01-01

    Background HIV-1 has proved to infect regulatory T cells (Treg) modifying their phenotype and impairing their suppressive capacity. As Treg cells are a crucial component in the preservation of the immune homeostasis, we researched that the antiviral capacity of carboxilan dendrimers prevents the HIV-1 infection of Treg and their effects. The phenotype and suppressive capacity of Treg treated or non-treated with carbosilane dendrimers were studied by flow cytometry. Treated and non-treated Treg from healthy donors were infected with HIV-1NL4.3. The infection of Treg cells by HIV-1, and protective effect of two dendrimers were determined by measuring antigen p24gag in the supernatant of the culture and intracellular. Results The Treg cells were treated with cationic and anionic carbosilane dendrimers. The results showed that both dendrimers did not modify the phenotype and functionality of Treg cells compared with non- treated Treg cells. Anionic dendrimers showed high biocompatibility with normal activity of the Treg cells and in antiviral assays. These dendrimers were highly active against HIV-1 preventing the infection of Treg, and were able to protect the Treg from the Foxp3 downregulation induced by the HIV-1 infection. Conclusions This is the first work showing that the in vitro use of anionic dendrimers prevent the HIV-1 replication and the infection of expanded Treg cells in culture, which raises the possibility to use Treg cells therapeutically in HIV-1-infected subjects. PMID:26785250

  8. Infection with Toxoplasma gondii results in dysregulation of the host cell cycle

    PubMed Central

    Molestina, Robert E.; El-Guendy, Nadia; Sinai, Anthony P.

    2009-01-01

    SUMMARY Mammalian cells infected with Toxoplasma gondii are characterized by a profound reprogramming of gene expression. We examined whether such transcriptional responses were linked to changes in the cell cycle of the host. Human foreskin fibroblasts (HFF) in the G0/G1 phase of the cell cycle were infected with T. gondii and FACS analysis of DNA content was performed. Cell cycle profiles revealed a promotion into the S phase followed by an arrest towards the G2/M boundary with infection. This response was markedly different from that of growth factor stimulation which caused cell cycle entry and completion. Transcriptional profiles of T. gondii-infected HFF showed sustained increases in transcripts associated with a G1/S transition and DNA synthesis coupled to an abrogation of cell cycle regulators critical in G2/M transition relative to growth factor stimulation. These divergent responses correlated with a distinct temporal modulation of the critical cell cycle regulator kinase ERK by infection. While the kinetics of ERK phosphorylation by EGF showed rapid and sustained activation, infected cells displayed an oscillatory pattern of activation. Our results suggest that T. gondii infection induces and maintains a “proliferation response” in the infected cell which may fulfill critical growth requirements of the parasite during intracellular residence. PMID:18182087

  9. Comparative Proteomic Analysis of Wild-Type and SAP Domain Mutant Foot-and-Mouth Disease Virus-Infected Porcine Cells Identifies the Ubiquitin-Activating Enzyme UBE1 Required for Virus Replication.

    PubMed

    Zhu, Zixiang; Yang, Fan; Zhang, Keshan; Cao, Weijun; Jin, Ye; Wang, Guoqing; Mao, Ruoqing; Li, Dan; Guo, Jianhong; Liu, Xiangtao; Zheng, Haixue

    2015-10-01

    Leader protein (L(pro)) of foot-and-mouth disease virus (FMDV) manipulates the activities of several host proteins to promote viral replication and pathogenicity. L(pro) has a conserved protein domain SAP that is suggested to subvert interferon (IFN) production to block antiviral responses. However, apart from blocking IFN production, the roles of the SAP domain during FMDV infection in host cells remain unknown. Therefore, we identified host proteins associated with the SAP domain of L(pro) by a high-throughput quantitative proteomic approach [isobaric tags for relative and absolute quantitation (iTRAQ) in conjunction with liquid chromatography/electrospray ionization tandem mass spectrometry]. Comparison of the differentially regulated proteins in rA/FMDVΔmSAP- versus rA/FMDV-infected SK6 cells revealed 45 down-regulated and 32 up-regulated proteins that were mostly associated with metabolic, ribosome, spliceosome, and ubiquitin-proteasome pathways. The results also imply that the SAP domain has a function similar to SAF-A/B besides its potential protein inhibitor of activated signal transducer and activator of transcription (PIAS) function. One of the identified proteins UBE1 was further analyzed and displayed a novel role for the SAP domain of L(pro). Overexpression of UBE1 enhanced the replication of FMDV, and knockdown of UBE1 decreased FMDV replication. This shows that FMDV manipulates UBE1 for increased viral replication, and the SAP domain was involved in this process.

  10. Dichotomy between T Cell and B Cell Tolerance to Neonatal Retroviral Infection Permits T Cell Therapy

    PubMed Central

    Mavrommatis, Bettina; Baudino, Lucie; Levy, Prisca; Merkenschlager, Julia; Eksmond, Urszula; Donnarumma, Tiziano; Young, George; Stoye, Jonathan

    2016-01-01

    Elucidation of the immune requirements for control or elimination of retroviral infection remains an important aim. We studied the induction of adaptive immunity to neonatal infection with a murine retrovirus, under conditions leading to immunological tolerance. We found that the absence of either maternal or offspring adaptive immunity permitted efficient vertical transmission of the retrovirus. Maternal immunodeficiency allowed the retrovirus to induce central Th cell tolerance in the infected offspring. In turn, this compromised the offspring’s ability to mount a protective Th cell–dependent B cell response. However, in contrast to T cells, offspring B cells were not centrally tolerized and retained their ability to respond to the infection when provided with T cell help. Thus, escape of retrovirus-specific B cells from deletional tolerance offers the opportunity to induce protective retroviral immunity by restoration of retrovirus-specific T cell help, suggesting similar T cell immunotherapies for persistent viral infections. PMID:27647833

  11. Sensing of Immature Particles Produced by Dengue Virus Infected Cells Induces an Antiviral Response by Plasmacytoid Dendritic Cells

    PubMed Central

    Hillaire, Marine L. B.; Dejnirattisai, Wanwisa; Mongkolsapaya, Juthathip; Screaton, Gavin R.; Davidson, Andrew D.; Dreux, Marlène

    2014-01-01

    Dengue virus (DENV) is the leading cause of mosquito-borne viral illness and death in humans. Like many viruses, DENV has evolved potent mechanisms that abolish the antiviral response within infected cells. Nevertheless, several in vivo studies have demonstrated a key role of the innate immune response in controlling DENV infection and disease progression. Here, we report that sensing of DENV infected cells by plasmacytoid dendritic cells (pDCs) triggers a robust TLR7-dependent production of IFNα, concomitant with additional antiviral responses, including inflammatory cytokine secretion and pDC maturation. We demonstrate that unlike the efficient cell-free transmission of viral infectivity, pDC activation depends on cell-to-cell contact, a feature observed for various cell types and primary cells infected by DENV, as well as West Nile virus, another member of the Flavivirus genus. We show that the sensing of DENV infected cells by pDCs requires viral envelope protein-dependent secretion and transmission of viral RNA. Consistently with the cell-to-cell sensing-dependent pDC activation, we found that DENV structural components are clustered at the interface between pDCs and infected cells. The actin cytoskeleton is pivotal for both this clustering at the contacts and pDC activation, suggesting that this structural network likely contributes to the transmission of viral components to the pDCs. Due to an evolutionarily conserved suboptimal cleavage of the precursor membrane protein (prM), DENV infected cells release uncleaved prM containing-immature particles, which are deficient for membrane fusion function. We demonstrate that cells releasing immature particles trigger pDC IFN response more potently than cells producing fusion-competent mature virus. Altogether, our results imply that immature particles, as a carrier to endolysosome-localized TLR7 sensor, may contribute to regulate the progression of dengue disease by eliciting a strong innate response. PMID

  12. Macrophage cell death upon intracellular bacterial infection

    PubMed Central

    Lai, Xin-He; Xu, Yunsheng; Chen, Xiao-Ming; Ren, Yi

    2015-01-01

    Macrophage-pathogen interaction is a complex process and the outcome of this tag-of-war for both sides is to live or die. Without attempting to be comprehensive, this review will discuss the complexity and significance of the interaction outcomes between macrophages and some facultative intracellular bacterial pathogens as exemplified by Francisella, Salmonella, Shigella and Yersinia. Upon bacterial infection, macrophages can die by a variety of ways, such as apoptosis, autophagic cell death, necrosis, necroptosis, oncosis, pyronecrosis, pyroptosis etc, which is the focus of this review. PMID:26690967

  13. Reduced Frequencies and Activation of Regulatory T Cells After the Treatment of HIV-1-Infected Individuals with the CCR5 Antagonist Maraviroc Are Associated with a Reduction in Viral Loads Rather Than a Direct Effect of the Drug on Regulatory T Cells.

    PubMed

    Joedicke, Jara J; Dirks, Miriam; Esser, Stefan; Verheyen, Jens; Dittmer, Ulf

    2016-04-01

    Regulatory T cells (Tregs) play an important role in the pathogenesis of HIV-1 infection and they frequently express the chemokine receptor CCR5. We therefore investigated whether antiretroviral treatment with the CCR5 antagonist Maraviroc affected Tregs in chronically HIV-1-infected individuals. HIV-1-infected patients with high viral loads had elevated frequencies of activated Tregs in the peripheral blood compared with healthy controls. In patients successfully treated with antiretroviral drugs (undetectable viral loads), the frequency and the activation status of Tregs were comparable with healthy controls without any specific effect related to the treatment with Maraviroc. These results indicate that the control of viral replication in general rather than a direct binding of Maraviroc to CCR5-positive Tregs influences Treg responses in successfully treated chronically HIV-1-infected individuals.

  14. Cumulative mechanisms of lymphoid tissue fibrosis and T cell depletion in HIV-1 and SIV infections

    PubMed Central

    Zeng, Ming; Smith, Anthony J.; Wietgrefe, Stephen W.; Southern, Peter J.; Schacker, Timothy W.; Reilly, Cavan S.; Estes, Jacob D.; Burton, Gregory F.; Silvestri, Guido; Lifson, Jeffrey D.; Carlis, John V.; Haase, Ashley T.

    2011-01-01

    The hallmark of HIV-1 and SIV infections is CD4+ T cell depletion. Both direct cell killing and indirect mechanisms related to immune activation have been suggested to cause the depletion of T cells. We have now identified a mechanism by which immune activation-induced fibrosis of lymphoid tissues leads to depletion of naive T cells in HIV-1 infected patients and SIV-infected rhesus macaques. The T regulatory cell response to immune activation increased procollagen production and subsequent deposition as fibrils via the TGF-β1 signaling pathway and chitinase 3-like-1 activity in fibroblasts in lymphoid tissues from patients infected with HIV-1. Collagen deposition restricted T cell access to the survival factor IL-7 on the fibroblastic reticular cell (FRC) network, resulting in apoptosis and depletion of T cells, which, in turn, removed a major source of lymphotoxin-β, a survival factor for FRCs during SIV infection in rhesus macaques. The resulting loss of FRCs and the loss of IL-7 produced by FRCs may thus perpetuate a vicious cycle of depletion of T cells and the FRC network. Because this process is cumulative, early treatment and antifibrotic therapies may offer approaches to moderate T cell depletion and improve immune reconstitution during HIV-1 infection. PMID:21393864

  15. Latent Membrane Protein LMP2A Impairs Recognition of EBV-Infected Cells by CD8+ T Cells.

    PubMed

    Rancan, Chiara; Schirrmann, Leah; Hüls, Corinna; Zeidler, Reinhard; Moosmann, Andreas

    2015-06-01

    The common pathogen Epstein-Barr virus (EBV) transforms normal human B cells and can cause cancer. Latent membrane protein 2A (LMP2A) of EBV supports activation and proliferation of infected B cells and is expressed in many types of EBV-associated cancer. It is not clear how latent EBV infection and cancer escape elimination by host immunity, and it is unknown whether LMP2A can influence the interaction of EBV-infected cells with the immune system. We infected primary B cells with EBV deleted for LMP2A, and established lymphoblastoid cell lines (LCLs). We found that CD8+ T cell clones showed higher reactivity against LMP2A-deficient LCLs compared to LCLs infected with complete EBV. We identified several potential mediators of this immunomodulatory effect. In the absence of LMP2A, expression of some EBV latent antigens was elevated, and cell surface expression of MHC class I was marginally increased. LMP2A-deficient LCLs produced lower amounts of IL-10, although this did not directly affect CD8+ T cell recognition. Deletion of LMP2A led to several changes in the cell surface immunophenotype of LCLs. Specifically, the agonistic NKG2D ligands MICA and ULBP4 were increased. Blocking experiments showed that NKG2D activation contributed to LCL recognition by CD8+ T cell clones. Our results demonstrate that LMP2A reduces the reactivity of CD8+ T cells against EBV-infected cells, and we identify several relevant mechanisms.

  16. Tyrosine phosphorylation of measles virus nucleocapsid protein in persistently infected neuroblastoma cells.

    PubMed Central

    Segev, Y; Ofir, R; Salzberg, S; Heller, A; Weinstein, Y; Isakov, N; Udem, S; Wolfson, M; Rager-Zisman, B

    1995-01-01

    Subacute sclerosing panencephalitis is a slowly progressing fatal human disease of the central nervous system which is a delayed sequel of measles virus (MV) infection. A typical pathological feature of this disease is the presence of viral ribonucleocapsid structures in the form of inclusion bodies and the absence of infectious virus or budding viral particles. The mechanisms governing the establishment and maintenance of a persistent MV infection in brain cells are still largely unknown. To understand the mechanisms underlying MV persistence in neuronal cells, a tissue culture model was studied. Clone NS20Y/MS of the murine neuroblastoma C1300 persistently infected with the wild-type Edmonston strain of MV secretes relatively high levels of alpha/beta interferon (IFN). As shown previously, treatment of the persistently infected cultures with anti-IFN serum converted the persistent state into a productive infection indicated by the appearance of multinucleated giant cells. In this study, we have investigated whether alpha/beta IFN produced by NS20Y/MS cells activates cellular protein tyrosine kinases which will induce tyrosine phosphorylating activity specific to virus-infected cells. We present data to show augmented protein tyrosine kinase activity in the persistently infected cells. We demonstrate that the MV N protein is phosphorylated on tyrosine in addition to serine and threonine in the persistent state but not in NS20Y cells acutely infected with MV. PMID:7884896

  17. Tyrosine phosphorylation of measles virus nucleocapsid protein in persistently infected neuroblastoma cells.

    PubMed

    Segev, Y; Ofir, R; Salzberg, S; Heller, A; Weinstein, Y; Isakov, N; Udem, S; Wolfson, M; Rager-Zisman, B

    1995-04-01

    Subacute sclerosing panencephalitis is a slowly progressing fatal human disease of the central nervous system which is a delayed sequel of measles virus (MV) infection. A typical pathological feature of this disease is the presence of viral ribonucleocapsid structures in the form of inclusion bodies and the absence of infectious virus or budding viral particles. The mechanisms governing the establishment and maintenance of a persistent MV infection in brain cells are still largely unknown. To understand the mechanisms underlying MV persistence in neuronal cells, a tissue culture model was studied. Clone NS20Y/MS of the murine neuroblastoma C1300 persistently infected with the wild-type Edmonston strain of MV secretes relatively high levels of alpha/beta interferon (IFN). As shown previously, treatment of the persistently infected cultures with anti-IFN serum converted the persistent state into a productive infection indicated by the appearance of multinucleated giant cells. In this study, we have investigated whether alpha/beta IFN produced by NS20Y/MS cells activates cellular protein tyrosine kinases which will induce tyrosine phosphorylating activity specific to virus-infected cells. We present data to show augmented protein tyrosine kinase activity in the persistently infected cells. We demonstrate that the MV N protein is phosphorylated on tyrosine in addition to serine and threonine in the persistent state but not in NS20Y cells acutely infected with MV.

  18. Targeted cytotoxic therapy kills persisting HIV infected cells during ART.

    PubMed

    Denton, Paul W; Long, Julie M; Wietgrefe, Stephen W; Sykes, Craig; Spagnuolo, Rae Ann; Snyder, Olivia D; Perkey, Katherine; Archin, Nancie M; Choudhary, Shailesh K; Yang, Kuo; Hudgens, Michael G; Pastan, Ira; Haase, Ashley T; Kashuba, Angela D; Berger, Edward A; Margolis, David M; Garcia, J Victor

    2014-01-01

    Antiretroviral therapy (ART) can reduce HIV levels in plasma to undetectable levels, but rather little is known about the effects of ART outside of the peripheral blood regarding persistent virus production in tissue reservoirs. Understanding the dynamics of ART-induced reductions in viral RNA (vRNA) levels throughout the body is important for the development of strategies to eradicate infectious HIV from patients. Essential to a successful eradication therapy is a component capable of killing persisting HIV infected cells during ART. Therefore, we determined the in vivo efficacy of a targeted cytotoxic therapy to kill infected cells that persist despite long-term ART. For this purpose, we first characterized the impact of ART on HIV RNA levels in multiple organs of bone marrow-liver-thymus (BLT) humanized mice and found that antiretroviral drug penetration and activity was sufficient to reduce, but not eliminate, HIV production in each tissue tested. For targeted cytotoxic killing of these persistent vRNA(+) cells, we treated BLT mice undergoing ART with an HIV-specific immunotoxin. We found that compared to ART alone, this agent profoundly depleted productively infected cells systemically. These results offer proof-of-concept that targeted cytotoxic therapies can be effective components of HIV eradication strategies.

  19. Impaired Phenotype and Function of T Follicular Helper Cells in HIV-1-Infected Children Receiving ART

    PubMed Central

    Bekele, Yonas; Amu, Sylvie; Bobosha, Kidist; Lantto, Rebecka; Nilsson, Anna; Endale, Birtukan; Gebre, Meseret; Aseffa, Abraham; Rethi, Bence; Howe, Rawleigh; Chiodi, Francesca

    2015-01-01

    Abstract T follicular helper (Tfh) cells are important components in development of specific humoral immune responses; whether the number and biology of Tfh cells is impaired in HIV-1-infected children is not yet studied. The frequency, phenotype, and function of Tfh cells and B cells were determined in blood of HIV-1-infected children receiving antiretroviral therapy (ART) and age-matched controls. Flow cytometry was used to characterize the frequency of Tfh cells and B cell subsets. Cytokine expression was measured after in vitro activation of Tfh cells. A reduced frequency of memory Tfh cells (P < 0.001) was identified in HIV-1-infected children and, on these cells, a reduced expression of programmed death-1 (PD-1) and inducible T cell costimulator (ICOS) (P < 0.001 and P < 0.01). Upon activation, the capacity of Tfh cells to express IL-4, an important cytokine for B cell function, was impaired in HIV-1-infected children. B cell subpopulations in HIV-1-infected children displayed significant differences from the control group: the frequency of resting memory (RM) B cells was reduced (P < 0.01) whereas the frequency of exhausted memory B cells increased (P < 0.001). Interestingly, the decline of RM cells correlated with the reduction of memory Tfh cells (P = 0.02). Our study shows that function and phenotype of Tfh cells, pivotal cells for establishment of adaptive B cell responses, are impaired during HIV-1 infection in children. A consistent reduction of memory Tfh cells is associated with declined frequencies of RM B cells, creating a novel link between dysfunctional features of these cell types, major players in establishment of humoral immunity. PMID:26166114

  20. Apoptosis and necrosis in vaccinia virus-infected HeLa G and BSC-40 cells.

    PubMed

    Liskova, Jana; Knitlova, Jarmila; Honner, Richard; Melkova, Zora

    2011-09-01

    In most cells, vaccinia virus (VACV) infection is considered to cause a lytic cell death, an equivalent of necrosis. However, upon infection of the epithelial cell lines HeLa G and BSC-40 with VACV strain Western Reserve (WR), we have previously observed an increased activation of and activity attributable to caspases, a typical sign of apoptosis. In this paper, we have further analyzed the type of cell death in VACV-infected cells HeLa G and BSC-40. In a cell-based flow cytometric assay, we showed a specific activation of caspase-2 and 4 in HeLa G and BSC-40 cells infected with VACV, strain WR, while we did not find any effects of inhibitors of calpain and cathepsin D and E. The actual activity of the two caspases, but also of caspase-3, was then confirmed in lysates of infected HeLa G, but not in BSC-40 cells. Accordingly, poly(ADP)-ribose polymerase (PARP) cleavage was found increased only in infected HeLa G cells. Consequently, we have determined morphological features of apoptosis and/or activity of the executioner caspase-3 in infected HeLa G cells in situ, while only a background apoptosis was observed in infected BSC-40 cells. Finally, vaccination strains Dryvax and Praha were found to induce apoptosis in both HeLa G and BSC-40 cells, as characterized morphologically and by PARP cleavage. These findings may be important for understanding the differences in VACV-host interactions and post-vaccination complications in different individuals.

  1. Differences between Mycobacterium-Host Cell Relationships in Latent Tuberculous Infection of Mice Ex Vivo and Mycobacterial Infection of Mouse Cells In Vitro

    PubMed Central

    Ufimtseva, Elena

    2016-01-01

    The search for factors that account for the reproduction and survival of mycobacteria, including vaccine strains, in host cells is the priority for studies on tuberculosis. A comparison of BCG-mycobacterial loads in granuloma cells obtained from bone marrow and spleens of mice with latent tuberculous infection and cells from mouse bone marrow and peritoneal macrophage cultures infected with the BCG vaccine in vitro has demonstrated that granuloma macrophages each normally contained a single BCG-Mycobacterium, while those acutely infected in vitro had increased mycobacterial loads and death rates. Mouse granuloma cells were observed to produce the IFNγ, IL-1α, GM-CSF, CD1d, CD25, CD31, СD35, and S100 proteins. None of these activation markers were found in mouse cell cultures infected in vitro or in intact macrophages. Lack of colocalization of lipoarabinomannan-labeled BCG-mycobacteria with the lysosomotropic LysoTracker dye in activated granuloma macrophages suggests that these macrophages were unable to destroy BCG-mycobacteria. However, activated mouse granuloma macrophages could control mycobacterial reproduction in cells both in vivo and in ex vivo culture. By contrast, a considerable increase in the number of BCG-mycobacteria was observed in mouse bone marrow and peritoneal macrophages after BCG infection in vitro, when no expression of the activation-related molecules was detected in these cells. PMID:27066505

  2. Cell death by pyroptosis drives CD4 T-cell depletion in HIV-1 infection

    NASA Astrophysics Data System (ADS)

    Doitsh, Gilad; Galloway, Nicole L. K.; Geng, Xin; Yang, Zhiyuan; Monroe, Kathryn M.; Zepeda, Orlando; Hunt, Peter W.; Hatano, Hiroyu; Sowinski, Stefanie; Muñoz-Arias, Isa; Greene, Warner C.

    2014-01-01

    The pathway causing CD4 T-cell death in HIV-infected hosts remains poorly understood although apoptosis has been proposed as a key mechanism. We now show that caspase-3-mediated apoptosis accounts for the death of only a small fraction of CD4 T cells corresponding to those that are both activated and productively infected. The remaining over 95% of quiescent lymphoid CD4 T cells die by caspase-1-mediated pyroptosis triggered by abortive viral infection. Pyroptosis corresponds to an intensely inflammatory form of programmed cell death in which cytoplasmic contents and pro-inflammatory cytokines, including IL-1β, are released. This death pathway thus links the two signature events in HIV infection--CD4 T-cell depletion and chronic inflammation--and creates a pathogenic vicious cycle in which dying CD4 T cells release inflammatory signals that attract more cells to die. This cycle can be broken by caspase 1 inhibitors shown to be safe in humans, raising the possibility of a new class of `anti-AIDS' therapeutics targeting the host rather than the virus.

  3. Comparative study of human and rabbit cell infection with cell-free HTLV-I.

    PubMed

    Yamade, I; Isono, T; Ishiguro, T; Yoshida, Y

    1993-01-01

    Infection of human and rabbit cells with cell-free HTLV-I was studied by PCR analysis. Both human and rabbit PBL were infected similarly by cell-free virus of both human and rabbit cell origin. Cells were infected with the cell-free virus without prior treatment and regardless of the concentration of the culture supernatant containing the virus. Human and rabbit cell lines were also infected similarly by the cell-free virus, the proviral DNA persisting for more than two months. The culture supernatants of HTLV-I-producing cells could thus be a potential cause of laboratory infections. PMID:8423456

  4. Lactic dehydrogenase virus infection enhances parasite egg production and inhibits eosinophil and mast cell responses in mice infected with the nematode Nippostrongylus brasiliensis.

    PubMed Central

    Morimoto, M; Yamada, M; Arizono, N; Hayashi, T

    1998-01-01

    The effects of lactic dehydrogenase virus (LDV) infection on the protective immune responses to the nematode Nippostrongylus brasiliensis were studied. Mice with chronic LDV infection showed significantly higher levels of parasite egg production than non-LDV-infected (control) mice after N. brasiliensis infection. Concurrent LDV infection also suppressed peripheral blood eosinophilia and the lung mastocytosis induced by this nematode. LDV infection showed higher expression levels of the interferon-gamma (IFN-gamma) mRNA in lymph nodes compared with control mice before N. brasiliensis infection. In addition, the IgG2a production in LDV-infected mice was higher than that in control mice before and after N. brasiliensis infection. These results suggest that LDV infection modulates protective immune responses against N. brasiliensis infection by the activation of T-helper type 1 cells. PMID:9659227

  5. Macrophage Activation by Ursolic and Oleanolic Acids during Mycobacterial Infection.

    PubMed

    López-García, Sonia; Castañeda-Sanchez, Jorge Ismael; Jiménez-Arellanes, Adelina; Domínguez-López, Lilia; Castro-Mussot, Maria Eugenia; Hernández-Sanchéz, Javier; Luna-Herrera, Julieta

    2015-08-06

    Oleanolic (OA) and ursolic acids (UA) are triterpenes that are abundant in vegetables, fruits and medicinal plants. They have been described as active moieties in medicinal plants used for the treatment of tuberculosis. In this study, we analyzed the effects of these triterpenes on macrophages infected in vitro with Mycobacterium tuberculosis (MTB). We evaluated production of nitric oxide (NO), reactive oxygen species (ROS), and cytokines (TNF-α and TGF-β) as well as expression of cell membrane receptors (TGR5 and CD36) in MTB-infected macrophages following treatment with OA and UA. Triterpenes caused reduced MTB growth in macrophages, stimulated production of NO and ROS in the early phase, stimulated TNF-α, suppressed TGF-β and caused over-expression of CD36 and TGR5 receptors. Thus, our data suggest immunomodulatory properties of OA and UA on MTB infected macrophages. In conclusion, antimycobacterial effects induced by these triterpenes may be attributable to the conversion of macrophages from stage M2 (alternatively activated) to M1 (classically activated).

  6. Localised mitogenic activity in horses following infection with Streptococcus equi.

    PubMed

    McLean, R; Rash, N L; Robinson, C; Waller, A S; Paillot, R

    2015-06-01

    Streptococcus equi subspecies equi (S. equi) is the causative agent of strangles, a highly contagious upper respiratory disease of equids. Streptococcus equi produces superantigens (sAgs), which are thought to contribute to strangles pathogenicity through non-specific T-cell activation and pro-inflammatory response. Streptococcus equi infection induces abscesses in the lymph nodes of the head and neck. In some individuals, some abscess material remains into the guttural pouch and inspissates over time to form chondroids which can harbour live S. equi. The aim of this study was to determine the sites of sAg production during infection and therefore improve our understanding of their role. Abscess material, chondroids and serum collected from Equidae with signs of strangles were tested in mitogenic assays. Mitogenic sAg activity was only detected in abscess material and chondroids. Our data support the localised in vivo activity of sAg during both acute and carrier phases of S. equi infection.

  7. Macrophage Activation by Ursolic and Oleanolic Acids during Mycobacterial Infection.

    PubMed

    López-García, Sonia; Castañeda-Sanchez, Jorge Ismael; Jiménez-Arellanes, Adelina; Domínguez-López, Lilia; Castro-Mussot, Maria Eugenia; Hernández-Sanchéz, Javier; Luna-Herrera, Julieta

    2015-01-01

    Oleanolic (OA) and ursolic acids (UA) are triterpenes that are abundant in vegetables, fruits and medicinal plants. They have been described as active moieties in medicinal plants used for the treatment of tuberculosis. In this study, we analyzed the effects of these triterpenes on macrophages infected in vitro with Mycobacterium tuberculosis (MTB). We evaluated production of nitric oxide (NO), reactive oxygen species (ROS), and cytokines (TNF-α and TGF-β) as well as expression of cell membrane receptors (TGR5 and CD36) in MTB-infected macrophages following treatment with OA and UA. Triterpenes caused reduced MTB growth in macrophages, stimulated production of NO and ROS in the early phase, stimulated TNF-α, suppressed TGF-β and caused over-expression of CD36 and TGR5 receptors. Thus, our data suggest immunomodulatory properties of OA and UA on MTB infected macrophages. In conclusion, antimycobacterial effects induced by these triterpenes may be attributable to the conversion of macrophages from stage M2 (alternatively activated) to M1 (classically activated). PMID:26287131

  8. Combination of Antiretroviral Drugs and Radioimmunotherapy Specifically Kills Infected Cells from HIV-Infected Individuals

    PubMed Central

    Tsukrov, Dina; McFarren, Alicia; Morgenstern, Alfred; Bruchertseifer, Frank; Dolce, Eugene; Gorny, Miroslaw K.; Zolla-Pazner, Susan; Berman, Joan W.; Schoenbaum, Ellie; Zingman, Barry S.; Casadevall, Arturo; Dadachova, Ekaterina

    2016-01-01

    Eliminating virally infected cells is an essential component of any HIV eradication strategy. Radioimmunotherapy (RIT), a clinically established method for killing cells using radiolabeled antibodies, was recently applied to target HIV-1 gp41 antigen expressed on the surface of infected cells. Since gp41 expression by infected cells is likely downregulated in patients on antiretroviral therapy (ART), we evaluated the ability of RIT to kill ART-treated infected cells using both in vitro models and lymphocytes isolated from HIV-infected subjects. Human peripheral blood mononuclear cells (PBMCs) were infected with HIV and cultured in the presence of two clinically relevant ART combinations. Scatchard analysis of the 2556 human monoclonal antibody to HIV gp41 binding to the infected and ART-treated cells demonstrated sufficient residual expression of gp41 on the cell surface to warrant subsequent RIT. This is the first time the quantification of gp41 post-ART is being reported. Cells were then treated with Bismuth-213-labeled 2556 antibody. Cell survival was quantified by Trypan blue and residual viremia by p24 ELISA. Cell surface gp41 expression was assessed by Scatchard analysis. The experiments were repeated using PBMCs isolated from blood specimens obtained from 15 HIV-infected individuals: 10 on ART and 5 ART-naïve. We found that 213Bi-2556 killed ART-treated infected PBMCs and reduced viral production to undetectable levels. ART and RIT co-treatment was more effective at reducing viral load in vitro than either therapy alone, indicating that gp41 expression under ART was sufficient to allow 213Bi-2556 to deliver cytocidal doses of radiation to infected cells. This study provides proof of concept that 213Bi-2556 may represent an innovative and effective targeting method for killing HIV-infected cells treated with ART and supports continued development of 213Bi-2556 for co-administration with ART toward an HIV eradication strategy. PMID:27725930

  9. CD4 T Cell-Derived IFN-γ Plays a Minimal Role in Control of Pulmonary Mycobacterium tuberculosis Infection and Must Be Actively Repressed by PD-1 to Prevent Lethal Disease

    PubMed Central

    Sakai, Shunsuke; Kauffman, Keith D.; Sallin, Michelle A.; Sharpe, Arlene H.; Young, Howard A.; Ganusov, Vitaly V.; Barber, Daniel L.

    2016-01-01

    IFN-γ–producing CD4 T cells are required for protection against Mycobacterium tuberculosis (Mtb) infection, but the extent to which IFN-γ contributes to overall CD4 T cell-mediated protection remains unclear. Furthermore, it is not known if increasing IFN-γ production by CD4 T cells is desirable in Mtb infection. Here we show that IFN-γ accounts for only ~30% of CD4 T cell-dependent cumulative bacterial control in the lungs over the first six weeks of infection, but >80% of control in the spleen. Moreover, increasing the IFN-γ–producing capacity of CD4 T cells by ~2 fold exacerbates lung infection and leads to the early death of the host, despite enhancing control in the spleen. In addition, we show that the inhibitory receptor PD-1 facilitates host resistance to Mtb by preventing the detrimental over-production of IFN-γ by CD4 T cells. Specifically, PD-1 suppressed the parenchymal accumulation of and pathogenic IFN-γ production by the CXCR3+KLRG1-CX3CR1- subset of lung-homing CD4 T cells that otherwise mediates control of Mtb infection. Therefore, the primary role for T cell-derived IFN-γ in Mtb infection is at extra-pulmonary sites, and the host-protective subset of CD4 T cells requires negative regulation of IFN-γ production by PD-1 to prevent lethal immune-mediated pathology. PMID:27244558

  10. NK Cell Responses to Human Tick-Borne Encephalitis Virus Infection.

    PubMed

    Blom, Kim; Braun, Monika; Pakalniene, Jolita; Lunemann, Sebastian; Enqvist, Monika; Dailidyte, Laura; Schaffer, Marie; Lindquist, Lars; Mickiene, Aukse; Michaëlsson, Jakob; Ljunggren, Hans-Gustaf; Gredmark-Russ, Sara

    2016-10-01

    Tick-borne encephalitis virus (TBEV) is a flavivirus that is transferred to humans by infected ticks. The virus causes tick-borne encephalitis, a severe infection of the CNS with a high risk for long-lasting sequelae. Currently, no treatment exists for the disease. Understanding the cellular immune response to this infection is important to gain further understanding into the pathogenesis, treatment, and prevention of the disease. NK cells are known to participate in the control of viral infections. We performed a longitudinal analysis of the human NK cell response to TBEV infection in a cohort of infected individuals from the onset of severe clinical symptoms to the convalescence phase. NK cell activation, as measured by expression of Ki67, was apparent at the time of hospitalization. By 3 wk after hospitalization, it decreased to levels seen in healthy controls. Concomitant with the increase in NK cell activation, augmented levels of IL-12, IL-15, IL-18, IFN-γ, and TNF were detected in patient plasma. This TBEV-induced NK cell activation was restricted predominantly to differentiated CD57(+)CD56(dim) NK cells. Functionally, CD56(dim) NK cells responded poorly to target cells at the time of hospitalization, but they recovered functional capacity to control levels during the convalescent phase. In contrast, the responsiveness of NK cells to cytokine stimulation remained intact throughout the disease. These findings demonstrate that NK cells respond to TBEV infection with characteristics that are distinct from those of other human viral infections and provide insights into the NK cell response to clinical TBEV infection. PMID:27543616

  11. Apoptosis in response to microbial infection induces autoreactive TH17 cells.

    PubMed

    Campisi, Laura; Barbet, Gaetan; Ding, Yi; Esplugues, Enric; Flavell, Richard A; Blander, J Magarian

    2016-09-01

    Microbial infections often precede the onset of autoimmunity. How infections trigger autoimmunity remains poorly understood. We investigated the possibility that infection might create conditions that allow the stimulatory presentation of self peptides themselves and that this might suffice to elicit autoreactive T cell responses that lead to autoimmunity. Self-reactive CD4(+) T cells are major drivers of autoimmune disease, but their activation is normally prevented through regulatory mechanisms that limit the immunostimulatory presentation of self antigens. Here we found that the apoptosis of infected host cells enabled the presentation of self antigens by major histocompatibility complex class II molecules in an inflammatory context. This was sufficient for the generation of an autoreactive TH17 subset of helper T cells, prominently associated with autoimmune disease. Once induced, the self-reactive TH17 cells promoted auto-inflammation and autoantibody generation. Our findings have implications for how infections precipitate autoimmunity. PMID:27455420

  12. Massive Activation of Archaeal Defense Genes during Viral Infection

    PubMed Central

    Voet, Marleen; Sismeiro, Odile; Dillies, Marie-Agnes; Jagla, Bernd; Coppée, Jean-Yves; Sezonov, Guennadi; Forterre, Patrick; van der Oost, John; Lavigne, Rob

    2013-01-01

    Archaeal viruses display unusually high genetic and morphological diversity. Studies of these viruses proved to be instrumental for the expansion of knowledge on viral diversity and evolution. The Sulfolobus islandicus rod-shaped virus 2 (SIRV2) is a model to study virus-host interactions in Archaea. It is a lytic virus that exploits a unique egress mechanism based on the formation of remarkable pyramidal structures on the host cell envelope. Using whole-transcriptome sequencing, we present here a global map defining host and viral gene expression during the infection cycle of SIRV2 in its hyperthermophilic host S. islandicus LAL14/1. This information was used, in combination with a yeast two-hybrid analysis of SIRV2 protein interactions, to advance current understanding of viral gene functions. As a consequence of SIRV2 infection, transcription of more than one-third of S. islandicus genes was differentially regulated. While expression of genes involved in cell division decreased, those genes playing a role in antiviral defense were activated on a large scale. Expression of genes belonging to toxin-antitoxin and clustered regularly interspaced short palindromic repeat (CRISPR)-Cas systems was specifically pronounced. The observed different degree of activation of various CRISPR-Cas systems highlights the specialized functions they perform. The information on individual gene expression and activation of antiviral defense systems is expected to aid future studies aimed at detailed understanding of the functions and interplay of these systems in vivo. PMID:23698312

  13. Waking up T cells to counteract chronic infections.

    PubMed

    Rouse, Barry T; Masopust, David

    2006-05-01

    Memory T-cell responses generated in chronic viral infections can show functional defects contributing to poor viral control. Recently, signaling through the PD-1 receptor on CD8+ T cells was shown to cause cells to express an exhausted phenotype in an animal model of chronic infection. By blocking the interaction of PD-1 with its ligand PD-L1, virus-specific CD8+ T cells exhibited expansion and improved infection control. This approach could prove valuable to manage chronic infections.

  14. The Aspergillus fumigatus pkcAG579R Mutant Is Defective in the Activation of the Cell Wall Integrity Pathway but Is Dispensable for Virulence in a Neutropenic Mouse Infection Model

    PubMed Central

    Rocha, Marina Campos; de Godoy, Krissia Franco; de Castro, Patrícia Alves; Hori, Juliana Issa; Bom, Vinícius Leite Pedro; Brown, Neil Andrew; da Cunha, Anderson Ferreira; Goldman, Gustavo Henrique; Malavazi, Iran

    2015-01-01

    Aspergillus fumigatus is an opportunistic human pathogen, which causes the life-threatening disease, invasive pulmonary aspergillosis. In fungi, cell wall homeostasis is controlled by the conserved Cell Wall Integrity (CWI) pathway. In A. fumigatus this signaling cascade is partially characterized, but the mechanisms by which it is activated are not fully elucidated. In this study we investigated the role of protein kinase C (PkcA) in this signaling cascade. Our results suggest that pkcA is an essential gene and is activated in response to cell wall stress. Subsequently, we constructed and analyzed a non-essential A. fumigatus pkcAG579R mutant, carrying a Gly579Arg substitution in the PkcA C1B regulatory domain. The pkcAG579R mutation has a reduced activation of the downstream Mitogen-Activated Protein Kinase, MpkA, resulting in the altered expression of genes encoding cell wall-related proteins, markers of endoplasmic reticulum stress and the unfolded protein response. Furthermore, PkcAG579R is involved in the formation of proper conidial architecture and protection to oxidative damage. The pkcAG579R mutant elicits increased production of TNF-α and phagocytosis but it has no impact on virulence in a murine model of invasive pulmonary aspergillosis. These results highlight the importance of PkcA to the CWI pathway but also indicated that additional regulatory circuits may be involved in the biosynthesis and/or reinforcement of the A. fumigatus cell wall during infection. PMID:26295576

  15. Propofol Increases Host Susceptibility to Microbial Infection by Reducing Subpopulations of Mature Immune Effector Cells at Sites of Infection

    PubMed Central

    Visvabharathy, Lavanya; Xayarath, Bobbi; Weinberg, Guy; Shilling, Rebecca A.; Freitag, Nancy E.

    2015-01-01

    Anesthetics are known to modulate host immune responses, but separating the variables of surgery from anesthesia when analyzing hospital acquired infections is often difficult. Here, the bacterial pathogen Listeria monocytogenes (Lm) was used to assess the impact of the common anesthetic propofol on host susceptibility to infection. Brief sedation of mice with physiologically relevant concentrations of propofol increased bacterial burdens in target organs by more than 10,000-fold relative to infected control animals. The adverse effects of propofol sedation on immune clearance of Lm persisted after recovery from sedation, as animals given the drug remained susceptible to infection for days following anesthesia. In contrast to propofol, sedation with alternative anesthetics such as ketamine/xylazine or pentobarbital did not increase susceptibility to systemic Lm infection. Propofol altered systemic cytokine and chemokine expression during infection, and prevented effective bacterial clearance by inhibiting the recruitment and/or activity of immune effector cells at sites of infection. Propofol exposure induced a marked reduction in marginal zone macrophages in the spleens of Lm infected mice, resulting in bacterial dissemination into deep tissue. Propofol also significantly increased mouse kidney abscess formation following infection with the common nosocomial pathogen Staphylococcus aureus. Taken together, these data indicate that even brief exposure to propofol severely compromises host resistance to microbial infection for days after recovery from sedation. PMID:26381144

  16. Subgroup J avian leukosis virus infection inhibits autophagy in DF-1 cells

    PubMed Central

    2013-01-01

    Background Subgroup J avian leukosis virus (ALV-J) infection can induce tumor-related diseases in chickens. Previous studies by our laboratory demonstrated that ALV-J infection of DF-1 cells resulted in altered activity and phosphorylation of AKT. However, little is known about the subsequent activation of host DF-1 cells. Results In the current study, autophagy inhibition was observed for ALV-J infected DF-1 cells. Our data showed that the autophagosome protein, microtubule-associated protein 1 light chain 3-II (LC3-II), was reduced considerably in DF-1 cells infected with active ALV-J, while no change was observed for cells infected with inactivated ALV-J. Autophagy inhibition was also confirmed by fluorescence microscopy and transmission electron microscopy. Interestingly, when autophagy was promoted by rapamycin, the titers of ALV-J replication were decreased, and the replication level of ALV-J was significantly enhanced when atg5 (autophagy-related gene 5) was knocked out. Conclusions These results suggested that ALV-J infection could down-regulate autophagy in DF-1 cells during viral replication. This study is the first to report on the relationship between ALV-J infection and autophagy in DF-1 cells. PMID:23773913

  17. Retroviral infection of non-dividing cells: Old and new perspectives

    SciTech Connect

    Yamashita, Masahiro; Emerman, Michael . E-mail: memerman@fhcrc.org

    2006-01-05

    The dependence of retroviral replication on cell proliferation was described as early as 1958, although different classes of retroviruses are able to infect non-dividing cells with different efficiencies. For example, the human immunodeficiency virus (HIV) and other lentiviruses infect most non-dividing cells nearly as well as dividing cells, while the gammaretroviruses such as the murine leukemia virus (MLV) cannot infect non-dividing cells, and other retroviruses have intermediate phenotypes. One exception to the ability of HIV to infect non-dividing cells involves resting CD4+ T cells in vitro where there are multiple restrictions. However, recent data show that there is massive infection of non-activated CD4+ T cell during acute infection which suggests that the situation is different in vivo. Finally, much work trying to explain the difference between HIV and MLV in non-dividing cells has focused on describing the ability of HIV to enter the nucleus during interphase. However, we suggest that events in the viral lifecycle other than nuclear import may be more important in determining the ability of a given retrovirus to infect non-dividing cells.

  18. Norovirus Antagonism of B cell Antigen Presentation Results in Impaired Control of Acute Infection

    PubMed Central

    Zhu, Shu; Jones, Melissa K.; Hickman, Danielle; Han, Shuhong; Reeves, Westley; Karst, Stephanie M.

    2016-01-01

    Human noroviruses are a leading cause of gastroenteritis so vaccine development is desperately needed. Elucidating viral mechanisms of immune antagonism can provide key insight into designing effective immunization platforms. We recently revealed that B cells are targets of norovirus infection. Because noroviruses can regulate antigen presentation by infected macrophages and B cells can function as antigen presenting cells, we tested whether noroviruses regulate B cell-mediated antigen presentation and the biological consequence of such regulation. Indeed, murine noroviruses could prevent B cell expression of antigen presentation molecules and this directly correlated with impaired control of acute infection. In addition to B cells, acute control required MHC class I molecules, CD8+ T cells, and granzymes, supporting a model whereby B cells act as antigen presenting cells to activate cytotoxic CD8+ T cells. This immune pathway was active prior to the induction of antiviral antibody responses. As in macrophages, the minor structural protein VP2 regulated B cell antigen presentation in a virus-specific manner. Commensal bacteria were not required for activation of this pathway and ultimately only B cells were required for clearance of viral infection. These findings provide new insight into the role of B cells in stimulating antiviral CD8+ T cell responses. PMID:27007673

  19. Antiviral activity of lanatoside C against dengue virus infection.

    PubMed

    Cheung, Yan Yi; Chen, Karen Caiyun; Chen, Huixin; Seng, Eng Khuan; Chu, Justin Jang Hann

    2014-11-01

    Dengue infection poses a serious threat globally due to its recent rapid spread and rise in incidence. Currently, there is no approved vaccine or effective antiviral drug for dengue virus infection. In response to the urgent need for the development of an effective antiviral for dengue virus, the US Drug Collection library was screened in this study to identify compounds with anti-dengue activities. Lanatoside C, an FDA approved cardiac glycoside was identified as a candidate anti-dengue compound. Our data revealed that lanatoside C has an IC50 of 0.19μM for dengue virus infection in HuH-7 cells. Dose-dependent reduction in dengue viral RNA and viral proteins synthesis were also observed upon treatment with increasing concentrations of lanatoside C. Time of addition study indicated that lanatoside C inhibits the early processes of the dengue virus replication cycle. Furthermore, lanatoside C can effectively inhibit all four serotypes of dengue virus, flavivirus Kunjin, alphavirus Chikungunya and Sindbis virus as well as the human enterovirus 71. These findings suggest that lanatoside C possesses broad spectrum antiviral activity against several groups of positive-sense RNA viruses.

  20. Pathogenic hantaviruses direct the adherence of quiescent platelets to infected endothelial cells.

    PubMed

    Gavrilovskaya, Irina N; Gorbunova, Elena E; Mackow, Erich R

    2010-05-01

    Hantavirus infections are noted for their ability to infect endothelial cells, cause acute thrombocytopenia, and trigger 2 vascular-permeability-based diseases. However, hantavirus infections are not lytic, and the mechanisms by which hantaviruses cause capillary permeability and thrombocytopenia are only partially understood. The role of beta(3) integrins in hemostasis and the inactivation of beta(3) integrin receptors by pathogenic hantaviruses suggest the involvement of hantaviruses in altered platelet and endothelial cell functions that regulate permeability. Here, we determined that pathogenic hantaviruses bind to quiescent platelets via a beta(3) integrin-dependent mechanism. This suggests that platelets may contribute to hantavirus dissemination within infected patients and provides a means by which hantavirus binding to beta(3) integrin receptors prevents platelet activation. The ability of hantaviruses to bind platelets further suggested that cell-associated hantaviruses might recruit platelets to the endothelial cell surface. Our findings indicate that Andes virus (ANDV)- or Hantaan virus (HTNV)-infected endothelial cells specifically direct the adherence of calcein-labeled platelets. In contrast, cells comparably infected with nonpathogenic Tula virus (TULV) failed to recruit platelets to the endothelial cell surface. Platelet adherence was dependent on endothelial cell beta(3) integrins and neutralized by the addition of the anti-beta(3) Fab fragment, c7E3, or specific ANDV- or HTNV-neutralizing antibodies. These findings indicate that pathogenic hantaviruses displayed on the surface of infected endothelial cells bind platelets and that a platelet layer covers the surface of infected endothelial cells. This fundamentally changes the appearance of endothelial cells and has the potential to alter cellular immune responses, platelet activation, and endothelial cell functions that affect vascular permeability. Hantavirus-directed platelet quiescence and

  1. Gammaherpesvirus-driven plasma cell differentiation regulates virus reactivation from latently infected B lymphocytes.

    PubMed

    Liang, Xiaozhen; Collins, Christopher M; Mendel, Justin B; Iwakoshi, Neal N; Speck, Samuel H

    2009-11-01

    Gammaherpesviruses chronically infect their host and are tightly associated with the development of lymphoproliferative diseases and lymphomas, as well as several other types of cancer. Mechanisms involved in maintaining chronic gammaherpesvirus infections are poorly understood and, in particular, little is known about the mechanisms involved in controlling gammaherpesvirus reactivation from latently infected B cells in vivo. Recent evidence has linked plasma cell differentiation with reactivation of the human gammaherpesviruses EBV and KSHV through induction of the immediate-early viral transcriptional activators by the plasma cell-specific transcription factor XBP-1s. We now extend those findings to document a role for a gammaherpesvirus gene product in regulating plasma cell differentiation and thus virus reactivation. We have previously shown that the murine gammaherpesvirus 68 (MHV68) gene product M2 is dispensable for virus replication in permissive cells, but plays a critical role in virus reactivation from latently infected B cells. Here we show that in mice infected with wild type MHV68, virus infected plasma cells (ca. 8% of virus infected splenocytes at the peak of viral latency) account for the majority of reactivation observed upon explant of splenocytes. In contrast, there is an absence of virus infected plasma cells at the peak of latency in mice infected with a M2 null MHV68. Furthermore, we show that the M2 protein can drive plasma cell differentiation in a B lymphoma cell line in the absence of any other MHV68 gene products. Thus, the role of M2 in MHV68 reactivation can be attributed to its ability to manipulate plasma cell differentiation, providing a novel viral strategy to regulate gammaherpesvirus reactivation from latently infected B cells. We postulate that M2 represents a new class of herpesvirus gene products (reactivation conditioners) that do not directly participate in virus replication, but rather facilitate virus reactivation by

  2. Interleukin-1 alpha production during Rickettsia rickettsii infection of cultured endothelial cells: potential role in autocrine cell stimulation.

    PubMed Central

    Sporn, L A; Marder, V J

    1996-01-01

    Rickettsia rickettsii infection results in numerous responses by cultured endothelial cells, among them a rapid, transient increase in steady-state levels of tissue factor mRNA (L.A. Sporn, P.J. Haidaris, R.-J. Shi, Y. Nemerson, D.J. Silverman, and V.J. Marder, Blood 83:1527-1534, 1994). In this study, production of interleukin-1 (IL-1) was measured during infection and its potential role in autocrine cell stimulation was investigated. A fivefold increase in levels of IL-1 alpha antigen was measured in cell lysate samples by enzyme-linked immunosorbent assay at 18 h of infection. The majority of IL-1 alpha remained cell associated, as no significant increase was detected in culture medium. No IL-1 beta antigen was detected in cell lysates or culture medium from either control or infected cultures. A dramatic increase in the levels of IL-1 alpha mRNA occurred following infection, as measured by reverse transcriptase PCR, which revealed the appearance of the expected 421-kb product with RNA extracted from cells infected for 4 h and no detectable product from control cell samples. The presence of functional, cell-associated IL-1 alpha activity in infected cells was confirmed, following disruption, by the ability of the infected cells to induce tissue factor expression in target endothelial cells. Such induction was eliminated by pretreatment of the disrupted cell samples with neutralizing antibodies against IL-1 alpha but not against IL-1 beta. To investigate whether endogenously produced IL-1 participates in the stimulation of tissue factor expression, neutralizing antibodies against IL-1 or the IL-1 receptor antagonist were added to culture medium during infection. Both anti-IL-1 alpha and the IL-1 receptor antagonist resulted in approximately 40% inhibition of tissue factor expression, thus implicating IL-1 alpha in autocrine cell stimulation. PMID:8613368

  3. Inhibition of Interjacent Ribonucleic Acid (26S) Synthesis in Cells Infected by Sindbis Virus

    PubMed Central

    Scheele, Christina M.; Pfefferkorn, E. R.

    1969-01-01

    The interrelationship of viral ribonucleic acid (RNA) and protein synthesis in cells infected by Sindbis virus was investigated. When cultures were treated with puromycin early in the course of infection, the synthesis of interjacent RNA (26S) was preferentially inhibited. A similar result was obtained by shifting cells infected by one temperature-sensitive mutant defective in RNA synthesis from the permissive (29 C) to the nonpermissive (41.5 C) temperature. Under both conditions, the viral RNA produced appeared to be fully active biologically. Once underway, the synthesis of viral RNA in wild-type Sindbis infections did not require concomitant protein synthesis. PMID:5817400

  4. Treatment of primary HIV-1 infection with cyclosporin A coupled with highly active antiretroviral therapy

    PubMed Central

    Rizzardi, G. Paolo; Harari, Alexandre; Capiluppi, Brunella; Tambussi, Giuseppe; Ellefsen, Kim; Ciuffreda, Donatella; Champagne, Patrick; Bart, Pierre-Alexandre; Chave, Jean-Philippe; Lazzarin, Adriano; Pantaleo, Giuseppe

    2002-01-01

    Primary HIV-1 infection causes extensive immune activation, during which CD4+ T cell activation supports massive HIV-1 production. We tested the safety and the immune-modulating effects of combining cyclosporin A (CsA) treatment with highly active antiretroviral therapy (HAART) during primary HIV-1 infection. Nine adults with primary HIV-1 infection were treated with CsA along with HAART. At week 8, all patients discontinued CsA but maintained HAART. Viral replication was suppressed to a comparable extent in the CsA + HAART cohort and in 29 control patients whose primary infection was treated with HAART alone. CsA restored normal CD4+ T cell levels, both in terms of percentage and absolute numbers. The increase in CD4+ T cells was apparent within a week and persisted throughout the study period. CsA was not detrimental to virus-specific CD8+ or CD4+ T cell responses. At week 48, the proportion of IFN-γ–secreting CD4+ and CD4+CCR7– T cells was significantly higher in the CsA + HAART cohort than in the HAART-alone cohort. In conclusion, rapid shutdown of T cell activation in the early phases of primary HIV-1 infection can have long-term beneficial effects and establish a more favorable immunologic set-point. Appropriate, immune-based therapeutic interventions may represent a valuable complement to HAART for treating HIV infection. PMID:11877476

  5. The Differentiation and Protective Function of Cytolytic CD4 T Cells in Influenza Infection

    PubMed Central

    Brown, Deborah M.; Lampe, Anna T.; Workman, Aspen M.

    2016-01-01

    CD4 T cells that recognize peptide antigen in the context of class II MHC can differentiate into various subsets that are characterized by their helper functions. However, increasing evidence indicates that CD4 cells with direct cytolytic activity (CD4 CTL) play a role in chronic as well as acute infections, such as influenza A virus (IAV) infection. In the last couple of decades, techniques to measure the frequency and activity of these cytolytic cells has demonstrated their abundance in infections, such as human immunodeficiency virus, mouse pox, murine gamma herpes virus, cytomegalovirus, Epstein–Barr virus, and influenza among others. We now appreciate a greater role for CD4 CTL as direct effectors in viral infections and antitumor immunity through their ability to acquire perforin-mediated cytolytic activity and contribution to lysis of virally infected targets or tumors. As early as the 1980s, CD4 T cell clones with cytolytic potential were identified after influenza virus infection, yet much of this early work was dependent on in vitro culture and little was known about the physiological relevance of CD4 CTL. Here, we discuss the direct role CD4 CTL play in protection against lethal IAV infection and the factors that drive the generation of perforin-mediated lytic activity in CD4 cells in vivo during IAV infection. While focusing on CD4 CTL generated during IAV infection, we pull comparisons from the literature in other antiviral and antitumor systems. Further, we highlight what is currently known about CD4 CTL secondary and memory responses, as well as vaccination strategies to induce these potent killer cells that provide an extra layer of cell-mediated immune protection against heterosubtypic IAV infection. PMID:27014272

  6. The Differentiation and Protective Function of Cytolytic CD4 T Cells in Influenza Infection.

    PubMed

    Brown, Deborah M; Lampe, Anna T; Workman, Aspen M

    2016-01-01

    CD4 T cells that recognize peptide antigen in the context of class II MHC can differentiate into various subsets that are characterized by their helper functions. However, increasing evidence indicates that CD4 cells with direct cytolytic activity (CD4 CTL) play a role in chronic as well as acute infections, such as influenza A virus (IAV) infection. In the last couple of decades, techniques to measure the frequency and activity of these cytolytic cells has demonstrated their abundance in infections, such as human immunodeficiency virus, mouse pox, murine gamma herpes virus, cytomegalovirus, Epstein-Barr virus, and influenza among others. We now appreciate a greater role for CD4 CTL as direct effectors in viral infections and antitumor immunity through their ability to acquire perforin-mediated cytolytic activity and contribution to lysis of virally infected targets or tumors. As early as the 1980s, CD4 T cell clones with cytolytic potential were identified after influenza virus infection, yet much of this early work was dependent on in vitro culture and little was known about the physiological relevance of CD4 CTL. Here, we discuss the direct role CD4 CTL play in protection against lethal IAV infection and the factors that drive the generation of perforin-mediated lytic activity in CD4 cells in vivo during IAV infection. While focusing on CD4 CTL generated during IAV infection, we pull comparisons from the literature in other antiviral and antitumor systems. Further, we highlight what is currently known about CD4 CTL secondary and memory responses, as well as vaccination strategies to induce these potent killer cells that provide an extra layer of cell-mediated immune protection against heterosubtypic IAV infection. PMID:27014272

  7. The Differentiation and Protective Function of Cytolytic CD4 T Cells in Influenza Infection.

    PubMed

    Brown, Deborah M; Lampe, Anna T; Workman, Aspen M

    2016-01-01

    CD4 T cells that recognize peptide antigen in the context of class II MHC can differentiate into various subsets that are characterized by their helper functions. However, increasing evidence indicates that CD4 cells with direct cytolytic activity (CD4 CTL) play a role in chronic as well as acute infections, such as influenza A virus (IAV) infection. In the last couple of decades, techniques to measure the frequency and activity of these cytolytic cells has demonstrated their abundance in infections, such as human immunodeficiency virus, mouse pox, murine gamma herpes virus, cytomegalovirus, Epstein-Barr virus, and influenza among others. We now appreciate a greater role for CD4 CTL as direct effectors in viral infections and antitumor immunity through their ability to acquire perforin-mediated cytolytic activity and contribution to lysis of virally infected targets or tumors. As early as the 1980s, CD4 T cell clones with cytolytic potential were identified after influenza virus infection, yet much of this early work was dependent on in vitro culture and little was known about the physiological relevance of CD4 CTL. Here, we discuss the direct role CD4 CTL play in protection against lethal IAV infection and the factors that drive the generation of perforin-mediated lytic activity in CD4 cells in vivo during IAV infection. While focusing on CD4 CTL generated during IAV infection, we pull comparisons from the literature in other antiviral and antitumor systems. Further, we highlight what is currently known about CD4 CTL secondary and memory responses, as well as vaccination strategies to induce these potent killer cells that provide an extra layer of cell-mediated immune protection against heterosubtypic IAV infection.

  8. Activation of Hypoxia Inducible Factor 1 Is a General Phenomenon in Infections with Human Pathogens

    PubMed Central

    Werth, Nadine; Beerlage, Christiane; Rosenberger, Christian; Yazdi, Amir S.; Edelmann, Markus; Amr, Amro; Bernhardt, Wanja; von Eiff, Christof; Becker, Karsten; Schäfer, Andrea; Peschel, Andreas; Kempf, Volkhard A. J.

    2010-01-01

    Background Hypoxia inducible factor (HIF)-1 is the key transcriptional factor involved in the adaptation process of cells and organisms to hypoxia. Recent findings suggest that HIF-1 plays also a crucial role in inflammatory and infectious diseases. Methodology/Principal Findings Using patient skin biopsies, cell culture and murine infection models, HIF-1 activation was determined by immunohistochemistry, immunoblotting and reporter gene assays and was linked to cellular oxygen consumption. The course of a S. aureus peritonitis was determined upon pharmacological HIF-1 inhibition. Activation of HIF-1 was detectable (i) in all ex vivo in biopsies of patients suffering from skin infections, (ii) in vitro using cell culture infection models and (iii) in vivo using murine intravenous and peritoneal S. aureus infection models. HIF-1 activation by human pathogens was induced by oxygen-dependent mechanisms. Small colony variants (SCVs) of S. aureus known to cause chronic infections did not result in cellular hypoxia nor in HIF-1 activation. Pharmaceutical inhibition of HIF-1 activation resulted in increased survival rates of mice suffering from a S. aureus peritonitis. Conclusions/Significance Activation of HIF-1 is a general phenomenon in infections with human pathogenic bacteria, viruses, fungi and protozoa. HIF-1-regulated pathways might be an attractive target to modulate the course of life-threatening infections. PMID:20644645

  9. Impairment in natural killer cells editing of immature dendritic cells by infection with a virulent Trypanosoma cruzi population.

    PubMed

    Batalla, Estela I; Pino Martínez, Agustina M; Poncini, Carolina V; Duffy, Tomás; Schijman, Alejandro G; González Cappa, Stella M; Alba Soto, Catalina D

    2013-01-01

    Early interactions between natural killer (NK) and dendritic cells (DC) shape the immune response at the frontier of innate and adaptive immunity. Activated NK cells participate in maturation or deletion of DCs that remain immature. We previously demonstrated that infection with a high virulence (HV) population of the protozoan parasite Trypanosoma cruzi downmodulates DC maturation and T-cell activation capacity. Here, we evaluated the role of NK cells in regulating the maturation level of DCs. Shortly after infection with HV T. cruzi, DCs in poor maturation status begin to accumulate in mouse spleen. Although infection induces NK cell cytotoxicity and cytokine production, NK cells from mice infected with HV T. cruzi exhibit reduced ability to lyse and fail to induce maturation of bone marrow-derived immature DCs (iDCs). NK-mediated lysis of iDCs is restored by in vitro blockade of the IL-10 receptor during NK-DC interaction or when NK cells are obtained from T. cruzi-infected IL-10 knockout mice. These results suggest that infection with a virulent T. cruzi strain alters NK cell-mediated regulation of the adaptive immune response induced by DCs. This regulatory circuit where IL-10 appears to participate might lead to parasite persistence but can also limit the induction of a vigorous tissue-damaging T-cell response.

  10. Type I interferon regulation of natural killer cell function in primary and secondary infections.

    PubMed

    Stackaruk, Michele L; Lee, Amanda J; Ashkar, Ali A

    2013-08-01

    The priming of natural killer (NK) cells by type I interferon (IFN) is necessary for protection against primary and secondary viral infections. However, the pathway by which type I IFN activates NK cells to elicit antiviral responses is controversial. There is evidence to suggest that type I IFN priming of NK cells occurs through both direct and indirect pathways. As with many innate mechanisms, type I IFN and NK cells also orchestrate the adaptive immune response and thus aid in protection against secondary infections. Type I IFN can shape CD4(+) T cell, B cell and humoral memory formation. In addition, long-lived NK cells can perform specific and enhanced memory-like protection in secondary infections. This review outlines the different mechanisms underlying type I IFN regulation of NK cells and how type I IFN and NK cells can be used as a therapeutic target in vaccinations.

  11. Highly active antiretroviral therapy potently suppresses HIV infection in humanized Rag2-/-gammac-/- mice.

    PubMed

    Sango, Kaori; Joseph, Aviva; Patel, Mahesh; Osiecki, Kristin; Dutta, Monica; Goldstein, Harris

    2010-07-01

    Humanized Rag2(-/-)gamma(c)(-/-) mice (Hu-DKO mice) become populated with functional human T cells, B cells, and dendritic cells following transplantation with human hematopoietic stem cells (HSC) and represent an improved model for studying HIV infection in vivo. In the current study we demonstrated that intrasplenic inoculation of hu-DKO mice with HIV-1 initiated a higher level of HIV infection than intravenous or intraperitoneal inoculation, associated with a reciprocal decrease in peripheral CD4(+) T cells and increase in peripheral CD8(+) T cells. HIV infection by intrasplenic injection increased serum levels of human IgG and IgM including human IgM and IgG specific for HIV-1 gp120. There was a significant inverse correlation between the level of HIV-1 infection and the extent of CD4(+) T cell depletion. Highly active antiretroviral therapy (HAART) initiated 1 week after HIV-1 inoculation markedly suppressed HIV-1 infection and prevented CD4(+) T cell depletion. Taken together, these findings demonstrate that intrasplenic injection of hu-DKO mice with HIV is a more efficient route of HIV infection than intravenous or intraperitoneal injection and generates increased infection associated with an increased anti-HIV humoral response. This animal model can serve as a valuable in vivo model to study the efficacy of anti-HIV therapies.

  12. Chlamydia muridarum infection-induced destruction of male germ cells and sertoli cells is partially prevented by Chlamydia major outer membrane protein-specific immune CD4 cells.

    PubMed

    Sobinoff, Alexander P; Dando, Samantha J; Redgrove, Kate A; Sutherland, Jessie M; Stanger, Simone J; Armitage, Charles W; Timms, Peter; McLaughlin, Eileen A; Beagley, Kenneth W

    2015-01-01

    Chlamydia trachomatis infections are increasingly prevalent worldwide. Male chlamydial infections are associated with urethritis, epididymitis, and orchitis; however, the role of Chlamydia in prostatitis and male factor infertility remains controversial. Using a model of Chlamydia muridarum infection in male C57BL/6 mice, we investigated the effects of chlamydial infection on spermatogenesis and determined the potential of immune T cells to prevent infection-induced outcomes. Antigen-specific CD4 T cells significantly reduced the infectious burden in the penile urethra, epididymis, and vas deferens. Infection disrupted seminiferous tubules, causing loss of germ cells at 4 and 8 wk after infection, with the most severely affected tubules containing only Sertoli cells. Increased mitotic proliferation, DNA repair, and apoptosis in spermatogonial cells and damaged germ cells were evident in atrophic tubules. Activated caspase 3 (casp3) staining revealed increased (6-fold) numbers of Sertoli cells with abnormal morphology that were casp3 positive in tubules of infected mice, indicating increased levels of apoptosis. Sperm count and motility were both decreased in infected mice, and there was a significant decrease in morphologically normal spermatozoa. Assessment of the spermatogonial stem cell population revealed a decrease in promyelocytic leukemia zinc finger (PLZF)-positive cells in the seminiferous tubules. Interestingly, adoptive transfer of antigen-specific CD4 cells, particularly T-helper 2-like cells, prior to infection prevented these effects in spermatogenesis and Sertoli cells. These data suggest that chlamydial infection adversely affects spermatogenesis and male fertility, and that vaccination can potentially prevent the spread of infection and these adverse outcomes.

  13. Natural Killer Cell Evasion Is Essential for Infection by Rhesus Cytomegalovirus.

    PubMed

    Sturgill, Elizabeth R; Malouli, Daniel; Hansen, Scott G; Burwitz, Benjamin J; Seo, Seongkyung; Schneider, Christine L; Womack, Jennie L; Verweij, Marieke C; Ventura, Abigail B; Bhusari, Amruta; Jeffries, Krystal M; Legasse, Alfred W; Axthelm, Michael K; Hudson, Amy W; Sacha, Jonah B; Picker, Louis J; Früh, Klaus

    2016-08-01

    The natural killer cell receptor NKG2D activates NK cells by engaging one of several ligands (NKG2DLs) belonging to either the MIC or ULBP families. Human cytomegalovirus (HCMV) UL16 and UL142 counteract this activation by retaining NKG2DLs and US18 and US20 act via lysomal degradation but the importance of NK cell evasion for infection is unknown. Since NKG2DLs are highly conserved in rhesus macaques, we characterized how NKG2DL interception by rhesus cytomegalovirus (RhCMV) impacts infection in vivo. Interestingly, RhCMV lacks homologs of UL16 and UL142 but instead employs Rh159, the homolog of UL148, to prevent NKG2DL surface expression. Rh159 resides in the endoplasmic reticulum and retains several NKG2DLs whereas UL148 does not interfere with NKG2DL expression. Deletion of Rh159 releases human and rhesus MIC proteins, but not ULBPs, from retention while increasing NK cell stimulation by infected cells. Importantly, RhCMV lacking Rh159 cannot infect CMV-naïve animals unless CD8+ cells, including NK cells, are depleted. However, infection can be rescued by replacing Rh159 with HCMV UL16 suggesting that Rh159 and UL16 perform similar functions in vivo. We therefore conclude that cytomegaloviral interference with NK cell activation is essential to establish but not to maintain chronic infection. PMID:27580123

  14. Natural Killer Cell Evasion Is Essential for Infection by Rhesus Cytomegalovirus.

    PubMed

    Sturgill, Elizabeth R; Malouli, Daniel; Hansen, Scott G; Burwitz, Benjamin J; Seo, Seongkyung; Schneider, Christine L; Womack, Jennie L; Verweij, Marieke C; Ventura, Abigail B; Bhusari, Amruta; Jeffries, Krystal M; Legasse, Alfred W; Axthelm, Michael K; Hudson, Amy W; Sacha, Jonah B; Picker, Louis J; Früh, Klaus

    2016-08-01

    The natural killer cell receptor NKG2D activates NK cells by engaging one of several ligands (NKG2DLs) belonging to either the MIC or ULBP families. Human cytomegalovirus (HCMV) UL16 and UL142 counteract this activation by retaining NKG2DLs and US18 and US20 act via lysomal degradation but the importance of NK cell evasion for infection is unknown. Since NKG2DLs are highly conserved in rhesus macaques, we characterized how NKG2DL interception by rhesus cytomegalovirus (RhCMV) impacts infection in vivo. Interestingly, RhCMV lacks homologs of UL16 and UL142 but instead employs Rh159, the homolog of UL148, to prevent NKG2DL surface expression. Rh159 resides in the endoplasmic reticulum and retains several NKG2DLs whereas UL148 does not interfere with NKG2DL expression. Deletion of Rh159 releases human and rhesus MIC proteins, but not ULBPs, from retention while increasing NK cell stimulation by infected cells. Importantly, RhCMV lacking Rh159 cannot infect CMV-naïve animals unless CD8+ cells, including NK cells, are depleted. However, infection can be rescued by replacing Rh159 with HCMV UL16 suggesting that Rh159 and UL16 perform similar functions in vivo. We therefore conclude that cytomegaloviral interference with NK cell activation is essential to establish but not to maintain chronic infection.

  15. Natural Killer Cell Evasion Is Essential for Infection by Rhesus Cytomegalovirus

    PubMed Central

    Sturgill, Elizabeth R.; Malouli, Daniel; Hansen, Scott G.; Burwitz, Benjamin J.; Schneider, Christine L.; Womack, Jennie L.; Verweij, Marieke C.; Ventura, Abigail B.; Bhusari, Amruta; Jeffries, Krystal M.; Legasse, Alfred W.; Axthelm, Michael K.; Hudson, Amy W.; Sacha, Jonah B.; Picker, Louis J.; Früh, Klaus

    2016-01-01

    The natural killer cell receptor NKG2D activates NK cells by engaging one of several ligands (NKG2DLs) belonging to either the MIC or ULBP families. Human cytomegalovirus (HCMV) UL16 and UL142 counteract this activation by retaining NKG2DLs and US18 and US20 act via lysomal degradation but the importance of NK cell evasion for infection is unknown. Since NKG2DLs are highly conserved in rhesus macaques, we characterized how NKG2DL interception by rhesus cytomegalovirus (RhCMV) impacts infection in vivo. Interestingly, RhCMV lacks homologs of UL16 and UL142 but instead employs Rh159, the homolog of UL148, to prevent NKG2DL surface expression. Rh159 resides in the endoplasmic reticulum and retains several NKG2DLs whereas UL148 does not interfere with NKG2DL expression. Deletion of Rh159 releases human and rhesus MIC proteins, but not ULBPs, from retention while increasing NK cell stimulation by infected cells. Importantly, RhCMV lacking Rh159 cannot infect CMV-naïve animals unless CD8+ cells, including NK cells, are depleted. However, infection can be rescued by replacing Rh159 with HCMV UL16 suggesting that Rh159 and UL16 perform similar functions in vivo. We therefore conclude that cytomegaloviral interference with NK cell activation is essential to establish but not to maintain chronic infection. PMID:27580123

  16. Salmonella typhimurium infection increases p53 acetylation in intestinal epithelial cells.

    PubMed

    Wu, Shaoping; Ye, Zhongde; Liu, Xingyin; Zhao, Yun; Xia, Yinglin; Steiner, Andrew; Petrof, Elaine O; Claud, Erika C; Sun, Jun

    2010-05-01

    The ability of Salmonella typhimurium to enter intestinal epithelial cells constitutes a crucial step in pathogenesis. Salmonella invasion of the intestinal epithelium requires bacterial type three secretion system. Type three secretion system is a transport device that injects virulence proteins, called effectors, to paralyze or reprogram the eukaryotic cells. Avirulence factor for Salmonella (AvrA) is a Salmonella effector that inhibits the host's inflammatory responses. The mechanism by which AvrA modulates host cell signaling is not entirely clear. p53 is situated at the crossroads of a network of signaling pathways that are essential for genotoxic and nongenotoxic stress responses. We hypothesized that Salmonella infection activates the p53 pathway. We demonstrated that Salmonella infection increased p53 acetylation. Cells infected with AvrA-sufficient Salmonella have increased p53 acetylation, whereas cells infected with AvrA-deficient Salmonella have less p53 acetylation. In a cell-free system, AvrA possessed acetyltransferase activity and used p53 as a substrate. AvrA expression increased p53 transcriptional activity and induced cell cycle arrest. HCT116 p53-/- cells had less inflammatory responses. In a mouse model of Salmonella infection, intestinal epithelial p53 acetylation was increased by AvrA expression. Our studies provide novel mechanistic evidence that Salmonella modulates the p53 pathway during intestinal inflammation and infection.

  17. Suppression of human immunodeficiency virus replication by ascorbate in chronically and acutely infected cells.

    PubMed Central

    Harakeh, S; Jariwalla, R J; Pauling, L

    1990-01-01

    We have studied the action of ascorbate (vitamin C) on human immunodeficiency virus type 1 (HIV-1), the etiological agent clinically associated with AIDS. We report the suppression of virus production and cell fusion in HIV-infected T-lymphocytic cell lines grown in the presence of nontoxic concentrations of ascorbate. In chronically infected cells expressing HIV at peak levels, ascorbate reduced the levels of extracellular reverse transcriptase (RT) activity (by greater than 99%) and of p24 antigen (by 90%) in the culture supernatant. Under similar conditions, no detectable inhibitory effects on cell viability, host metabolic activity, and protein synthesis were observed. In freshly infected CD4+ cells, ascorbate inhibited the formation of giant-cell syncytia (by approximately 93%). Exposure of cell-free virus to ascorbate at 37 degrees C for 1 day had no effect on its RT activity or syncytium-forming ability. Prolonged exposure of virus (37 degrees C for 4 days) in the presence of ascorbate (100-150 micrograms/ml) resulted in the drop by a factor of 3-14 in RT activity as compared to a reduction by a factor of 25-172 in extracellular RT released from chronically infected cells. These results indicate that ascorbate mediates an anti-HIV effect by diminishing viral protein production in infected cells and RT stability in extracellular virions. Images PMID:1698293

  18. Natural killer cells in hepatitis B virus infection.

    PubMed

    Wu, Shao-fei; Wang, Wen-jing; Gao, Yue-qiu

    2015-01-01

    Natural killer cells are a unique type of lymphocytes with cytotoxic capacity, and play important roles against tumors and infections. Recently, natural killer cells have been increasingly valued in the