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Sample records for inhibit hemolytic complement

  1. Complement in hemolytic anemia.

    PubMed

    Brodsky, Robert A

    2015-11-26

    Complement is increasingly being recognized as an important driver of human disease, including many hemolytic anemias. Paroxysmal nocturnal hemoglobinuria (PNH) cells are susceptible to hemolysis because of a loss of the complement regulatory proteins CD59 and CD55. Patients with atypical hemolytic uremic syndrome (aHUS) develop a thrombotic microangiopathy (TMA) that in most cases is attributable to mutations that lead to activation of the alternative pathway of complement. For optimal therapy, it is critical, but often difficult, to distinguish aHUS from other TMAs, such as thrombotic thrombocytopenic purpura; however, novel bioassays are being developed. In cold agglutinin disease (CAD), immunoglobulin M autoantibodies fix complement on the surface of red cells, resulting in extravascular hemolysis by the reticuloendothelial system. Drugs that inhibit complement activation are increasingly being used to treat these diseases. This article discusses the pathophysiology, diagnosis, and therapy for PNH, aHUS, and CAD. PMID:26582375

  2. Complement in hemolytic anemia.

    PubMed

    Brodsky, Robert A

    2015-01-01

    Complement is increasingly being recognized as an important driver of human disease, including many hemolytic anemias. Paroxysmal nocturnal hemoglobinuria (PNH) cells are susceptible to hemolysis because of a loss of the complement regulatory proteins CD59 and CD55. Patients with atypical hemolytic uremic syndrome (aHUS) develop a thrombotic microangiopathy (TMA) that in most cases is attributable to mutations that lead to activation of the alternative pathway of complement. For optimal therapy, it is critical, but often difficult, to distinguish aHUS from other TMAs, such as thrombotic thrombocytopenic purpura; however, novel bioassays are being developed. In cold agglutinin disease (CAD), immunoglobulin M autoantibodies fix complement on the surface of red cells, resulting in extravascular hemolysis by the reticuloendothelial system. Drugs that inhibit complement activation are increasingly being used to treat these diseases. This article discusses the pathophysiology, diagnosis, and therapy for PNH, aHUS, and CAD. PMID:26637747

  3. Role of Complement in Autoimmune Hemolytic Anemia.

    PubMed

    Berentsen, Sigbjørn

    2015-09-01

    The classification of autoimmune hemolytic anemias and the complement system are reviewed. In autoimmune hemolytic anemia of the warm antibody type, complement-mediated cell lysis is clinically relevant in a proportion of the patients but is hardly essential for hemolysis in most patients. Cold antibody-mediated autoimmune hemolytic anemias (primary cold agglutinin disease, secondary cold agglutinin syndrome and paroxysmal cold hemoglobinuria) are entirely complement-mediated disorders. In cold agglutinin disease, efficient therapies have been developed in order to target the pathogenic B-cell clone, but complement modulation remains promising in some clinical situations. No established therapy exists for secondary cold agglutinin syndrome and paroxysmal cold hemoglobinuria, and the possibility of therapeutic complement inhibition is interesting. Currently, complement modulation is not clinically documented in any autoimmune hemolytic anemia. The most relevant candidate drugs and possible target levels of action are discussed. PMID:26696798

  4. Role of Complement in Autoimmune Hemolytic Anemia

    PubMed Central

    Berentsen, Sigbjørn

    2015-01-01

    Summary The classification of autoimmune hemolytic anemias and the complement system are reviewed. In autoimmune hemolytic anemia of the warm antibody type, complement-mediated cell lysis is clinically relevant in a proportion of the patients but is hardly essential for hemolysis in most patients. Cold antibody-mediated autoimmune hemolytic anemias (primary cold agglutinin disease, secondary cold agglutinin syndrome and paroxysmal cold hemoglobinuria) are entirely complement-mediated disorders. In cold agglutinin disease, efficient therapies have been developed in order to target the pathogenic B-cell clone, but complement modulation remains promising in some clinical situations. No established therapy exists for secondary cold agglutinin syndrome and paroxysmal cold hemoglobinuria, and the possibility of therapeutic complement inhibition is interesting. Currently, complement modulation is not clinically documented in any autoimmune hemolytic anemia. The most relevant candidate drugs and possible target levels of action are discussed. PMID:26696798

  5. Intravenous and standard immune serum globulin preparations interfere with uptake of /sup 125/I-C3 onto sensitized erythrocytes and inhibit hemolytic complement activity

    SciTech Connect

    Berger, M.; Rosenkranz, P.; Brown, C.Y.

    1985-02-01

    Antibody-sensitized sheep erythrocytes were used as a model to determine the effects of therapeutic immune serum globulin (ISG) preparations on the ability of this particulate activator to fix C3 and initiate hemolysis. Both standard and intravenous forms of ISG inhibit uptake of /sup 125/I-C3, presumably by competing for the deposition of ''nascent'' C3b molecules onto the erythrocytes. Both forms of ISG also inhibit hemolytic activity of whole serum or purified complement components. The inhibition appears to be a specific property of IgG itself, since similar inhibition was not caused by equivalent concentrations of human serum albumin, and was not affected by the buffer in which the ISG was dissolved. Interference with C3 uptake onto antibody-sensitized platelets and/or inhibition of hemolytic complement activity could contribute to the efficacy of high dose intravenous ISG in idiopathic thrombocytopenic purpura.

  6. Initiation and Regulation of Complement during Hemolytic Transfusion Reactions

    PubMed Central

    Stowell, Sean R.; Winkler, Anne M.; Maier, Cheryl L.; Arthur, C. Maridith; Smith, Nicole H.; Girard-Pierce, Kathryn R.; Cummings, Richard D.; Zimring, James C.; Hendrickson, Jeanne E.

    2012-01-01

    Hemolytic transfusion reactions represent one of the most common causes of transfusion-related mortality. Although many factors influence hemolytic transfusion reactions, complement activation represents one of the most common features associated with fatality. In this paper we will focus on the role of complement in initiating and regulating hemolytic transfusion reactions and will discuss potential strategies aimed at mitigating or favorably modulating complement during incompatible red blood cell transfusions. PMID:23118779

  7. Drugs that inhibit complement.

    PubMed

    Schrezenmeier, Hubert; Höchsmann, Britta

    2012-02-01

    The complement system is an important part of the innate immune system. Complement plays a crucial role in the pathophysiology of many disorders. Despite the pivotal role of the complement system, an approved targeted inhibitor of a complement factor became available only recently. Eculizumab is a humanized monoclonal antibody that inhibits complement factor C5. It is a targeted, disease modifying, treatment of paroxysmal nocturnal hemoglobinuria (PNH). It was approved be the US FDA and the European Commission in 2007. In this review we will update the experience with eculizumab in PNH and discuss potential use of eculizumab in other disorders (e.g. cold agglutinin disease; atypical HUS) and new approaches to complement inhibition with drugs other than eculizumab. PMID:22169380

  8. Genetic Association of the Porcine C9 Complement Component with Hemolytic Complement Activity.

    PubMed

    Khoa, D V A; Wimmers, K

    2015-09-01

    The complement system is a part of the natural immune regulation mechanism against invading pathogens. Complement activation from three different pathways (classical, lectin, and alternative) leads to the formation of C5-convertase, an enzyme for cleavage of C5 into C5a and C5b, followed by C6, C7, C8, and C9 in membrane attack complex. The C9 is the last complement component of the terminal lytic pathway, which plays an important role in lysis of the target cells depending on its self-polymerization to form transmembrane channels. To address the association of C9 with traits related to disease resistance, the complete porcine C9 cDNA was comparatively sequenced to detect single nucleotide polymorphisms (SNPs) in pigs of the breeds Hampshire (HS), Duroc (DU), Berlin miniature pig (BMP), German Landrace (LR), Pietrain (PIE), and Muong Khuong (Vietnamese potbelly pig). Genotyping was performed in 417 F2 animals of a resource population (DUMI: DU×BMP) that were vaccinated with Mycoplasma hyopneumoniae, Aujeszky diseases virus and porcine respiratory and reproductive syndrome virus at 6, 14 and 16 weeks of age, respectively. Two SNPs were detected within the third exon. One of them has an amino acid substitution. The European porcine breeds (LR and PIE) show higher allele frequency of these SNPs than Vietnamese porcine breed (MK). Association of the substitution SNP with hemolytic complement activity indicated statistically significant differences between genotypes in the classical pathway but not in the alternative pathway. The interactions between eight time points of measurement of complement activity before and after vaccinations and genotypes were significantly different. The difference in hemolytic complement activity in the both pathways depends on genotype, kind of vaccine, age and the interaction to the other complement components. These results promote the porcine C9 (pC9) as a candidate gene to improve general animal health in the future. PMID:26194222

  9. Genetic Association of the Porcine C9 Complement Component with Hemolytic Complement Activity

    PubMed Central

    Khoa, D. V. A.; Wimmers, K.

    2015-01-01

    The complement system is a part of the natural immune regulation mechanism against invading pathogens. Complement activation from three different pathways (classical, lectin, and alternative) leads to the formation of C5-convertase, an enzyme for cleavage of C5 into C5a and C5b, followed by C6, C7, C8, and C9 in membrane attack complex. The C9 is the last complement component of the terminal lytic pathway, which plays an important role in lysis of the target cells depending on its self-polymerization to form transmembrane channels. To address the association of C9 with traits related to disease resistance, the complete porcine C9 cDNA was comparatively sequenced to detect single nucleotide polymorphisms (SNPs) in pigs of the breeds Hampshire (HS), Duroc (DU), Berlin miniature pig (BMP), German Landrace (LR), Pietrain (PIE), and Muong Khuong (Vietnamese potbelly pig). Genotyping was performed in 417 F2 animals of a resource population (DUMI: DU×BMP) that were vaccinated with Mycoplasma hyopneumoniae, Aujeszky diseases virus and porcine respiratory and reproductive syndrome virus at 6, 14 and 16 weeks of age, respectively. Two SNPs were detected within the third exon. One of them has an amino acid substitution. The European porcine breeds (LR and PIE) show higher allele frequency of these SNPs than Vietnamese porcine breed (MK). Association of the substitution SNP with hemolytic complement activity indicated statistically significant differences between genotypes in the classical pathway but not in the alternative pathway. The interactions between eight time points of measurement of complement activity before and after vaccinations and genotypes were significantly different. The difference in hemolytic complement activity in the both pathways depends on genotype, kind of vaccine, age and the interaction to the other complement components. These results promote the porcine C9 (pC9) as a candidate gene to improve general animal health in the future. PMID:26194222

  10. Gain-of-function mutations in complement factor B are associated with atypical hemolytic uremic syndrome

    PubMed Central

    de Jorge, Elena Goicoechea; Harris, Claire L.; Esparza-Gordillo, Jorge; Carreras, Luis; Arranz, Elena Aller; Garrido, Cynthia Abarrategui; López-Trascasa, Margarita; Sánchez-Corral, Pilar; Morgan, B. Paul; de Córdoba, Santiago Rodríguez

    2007-01-01

    Hemolytic uremic syndrome (HUS) is an important cause of acute renal failure in children. Mutations in one or more genes encoding complement-regulatory proteins have been reported in approximately one-third of nondiarrheal, atypical HUS (aHUS) patients, suggesting a defect in the protection of cell surfaces against complement activation in susceptible individuals. Here, we identified a subgroup of aHUS patients showing persistent activation of the complement alternative pathway and found within this subgroup two families with mutations in the gene encoding factor B (BF), a zymogen that carries the catalytic site of the complement alternative pathway convertase (C3bBb). Functional analyses demonstrated that F286L and K323E aHUS-associated BF mutations are gain-of-function mutations that result in enhanced formation of the C3bBb convertase or increased resistance to inactivation by complement regulators. These data expand our understanding of the genetic factors conferring predisposition to aHUS, demonstrate the critical role of the alternative complement pathway in the pathogenesis of aHUS, and provide support for the use of complement-inhibition therapies to prevent or reduce tissue damage caused by dysregulated complement activation. PMID:17182750

  11. Alternative Pathway of Complement in Children with Diarrhea-Associated Hemolytic Uremic Syndrome

    PubMed Central

    Thurman, Joshua M.; Marians, Russell; Emlen, Woodruff; Wood, Susan; Smith, Christopher; Akana, Hillary; Holers, V. Michael; Lesser, Martin; Kline, Myriam; Hoffman, Cathy; Christen, Erica

    2009-01-01

    Background and objectives: Diarrhea-associated hemolytic uremic syndrome (D+HUS) is a common cause of acute kidney injury in children. Mutations in alternative pathway (AP) complement regulatory proteins have been identified in severe cases of thrombotic microangiopathy, but the role of the AP in D+HUS has not been studied. Therefore, we determined whether plasma levels of markers of activation of the AP are increased in D+HUS and are biomarkers of the severity of renal injury that predict the need for dialysis. Design, setting, participants, & measurements: Patients were randomly selected from among participants in the HUS-SYNSORB Pk trial. Plasma samples were collected on days 1, 4, 7, and 10 after enrollment and day 28 after discharge from the hospital. Levels of two complement pathway products, Bb and SC5b-9, were determined by ELISA. Results: Seventeen children (6 boys and 11 girls; age, 5.4 ± 3.5 yr) were studied. Eight (47%) required dialysis support, and two had serious extrarenal events. On the day of enrollment, plasma levels of Bb and SC5b-9 were significantly increased in all patients compared with healthy controls (P < 0.01). The elevated concentrations normalized by day 28 after discharge. Circulating levels of complement pathway fragments did not correlate with severity of renal injury or occurrence of complications. Conclusions: Patients with acute-onset D+HUS manifest activation of the AP of complement that is temporally related to the onset of disease and that resolves within 1 mo. Therapies to inhibit the AP of complement may be useful in attenuating the severity of renal injury and extrarenal complications. PMID:19820137

  12. Red blood cell destruction in autoimmune hemolytic anemia: role of complement and potential new targets for therapy.

    PubMed

    Berentsen, Sigbjørn; Sundic, Tatjana

    2015-01-01

    Autoimmune hemolytic anemia (AIHA) is a collective term for several diseases characterized by autoantibody-initiated destruction of red blood cells (RBCs). Exact subclassification is essential. We provide a review of the respective types of AIHA with emphasis on mechanisms of RBC destruction, focusing in particular on complement involvement. Complement activation plays a definitive but limited role in warm-antibody AIHA (w-AIHA), whereas primary cold agglutinin disease (CAD), secondary cold agglutinin syndrome (CAS), and paroxysmal cold hemoglobinuria (PCH) are entirely complement-dependent disorders. The details of complement involvement differ among these subtypes. The theoretical background for therapeutic complement inhibition in selected patients is very strong in CAD, CAS, and PCH but more limited in w-AIHA. The optimal target complement component for inhibition is assumed to be important and highly dependent on the type of AIHA. Complement modulation is currently not an evidence-based therapy modality in any AIHA, but a number of experimental and preclinical studies are in progress and a few clinical observations have been reported. Clinical studies of new complement inhibitors are probably not far ahead. PMID:25705656

  13. Red Blood Cell Destruction in Autoimmune Hemolytic Anemia: Role of Complement and Potential New Targets for Therapy

    PubMed Central

    Berentsen, Sigbjørn

    2015-01-01

    Autoimmune hemolytic anemia (AIHA) is a collective term for several diseases characterized by autoantibody-initiated destruction of red blood cells (RBCs). Exact subclassification is essential. We provide a review of the respective types of AIHA with emphasis on mechanisms of RBC destruction, focusing in particular on complement involvement. Complement activation plays a definitive but limited role in warm-antibody AIHA (w-AIHA), whereas primary cold agglutinin disease (CAD), secondary cold agglutinin syndrome (CAS), and paroxysmal cold hemoglobinuria (PCH) are entirely complement-dependent disorders. The details of complement involvement differ among these subtypes. The theoretical background for therapeutic complement inhibition in selected patients is very strong in CAD, CAS, and PCH but more limited in w-AIHA. The optimal target complement component for inhibition is assumed to be important and highly dependent on the type of AIHA. Complement modulation is currently not an evidence-based therapy modality in any AIHA, but a number of experimental and preclinical studies are in progress and a few clinical observations have been reported. Clinical studies of new complement inhibitors are probably not far ahead. PMID:25705656

  14. Quiescent complement in nonhuman primates during E coli Shiga toxin-induced hemolytic uremic syndrome and thrombotic microangiopathy.

    PubMed

    Lee, Benjamin C; Mayer, Chad L; Leibowitz, Caitlin S; Stearns-Kurosawa, D J; Kurosawa, Shinichiro

    2013-08-01

    Enterohemorrhagic Escherichia coli (EHEC) produce ribosome-inactivating Shiga toxins (Stx1, Stx2) responsible for development of hemolytic uremic syndrome (HUS) and acute kidney injury (AKI). Some patients show complement activation during EHEC infection, raising the possibility of therapeutic targeting of complement for relief. Our juvenile nonhuman primate (Papio baboons) models of endotoxin-free Stx challenge exhibit full spectrum HUS, including thrombocytopenia, hemolytic anemia, and AKI with glomerular thrombotic microangiopathy. There were no significant increases in soluble terminal complement complex (C5b-9) levels after challenge with lethal Stx1 (n = 6) or Stx2 (n = 5) in plasma samples from T0 to euthanasia at 49.5 to 128 hours post-challenge. d-dimer and cell injury markers (HMGB1, histones) confirmed coagulopathy and cell injury. Thus, complement activation is not required for the development of thrombotic microangiopathy and HUS induced by EHEC Shiga toxins in these preclinical models, and benefits or risks of complement inhibition should be studied further for this infection. PMID:23733336

  15. Postoperative atypical hemolytic uremic syndrome associated with complement c3 mutation.

    PubMed

    Matsukuma, Eiji; Imamura, Atsushi; Iwata, Yusuke; Takeuchi, Takamasa; Yoshida, Yoko; Fujimura, Yoshihiro; Fan, Xinping; Miyata, Toshiyuki; Kuwahara, Takashi

    2014-01-01

    Atypical hemolytic uremic syndrome (aHUS) can be distinguished from typical or Shiga-like toxin-induced HUS. The clinical outcome is unfavorable; up to 50% of affected patients progress to end-stage renal failure and 25% die during the acute phase. Multiple conditions have been associated with aHUS, including infections, drugs, autoimmune conditions, transplantation, pregnancy, and metabolic conditions. aHUS in the nontransplant postsurgical period, however, is rare. An 8-month-old boy underwent surgical repair of tetralogy of Fallot. Neurological disturbances, acute renal failure, thrombocytopenia, and microangiopathic hemolytic anemia developed 25 days later, and aHUS was diagnosed. Further evaluation revealed that his complement factor H (CFH) level was normal and that anti-FH antibodies were not detected in his plasma. Sequencing of his CFH, complement factor I, membrane cofactor protein, complement factor B, and thrombomodulin genes was normal. His ADAMTS-13 (a disintegrin-like and metalloprotease with thrombospondin-1 repeats 13) activity was also normal. However, he had a potentially causative mutation (R425C) in complement component C3. Restriction fragment length polymorphism analysis revealed that his father and aunt also had this mutation; however, they had no symptoms of aHUS. We herein report a case of aHUS that developed after cardiovascular surgery and was caused by a complement C3 mutation. PMID:25431709

  16. Efficacy of plasma therapy in atypical hemolytic uremic syndrome with complement factor H mutations.

    PubMed

    Lapeyraque, Anne-Laure; Wagner, Eric; Phan, Véronique; Clermont, Marie-José; Merouani, Aïcha; Frémeaux-Bacchi, Véronique; Goodship, Timothy H J; Robitaille, Pierre

    2008-08-01

    Atypical hemolytic uremic syndrome (aHUS) frequently results in end-stage renal failure and can be lethal. Several studies have established an association between quantitative or qualitative abnormalities in complement factor H and aHUS. Although plasma infusion and exchange are often advocated, guidelines have yet to be established. Long-term outcome for patients under treatment is still unknown. We describe a patient who, at 7 months of age, presented with aHUS associated with combined de novo complement factor H mutations (S1191L and V1197A) on the same allele. Laboratory investigations showed normal levels of complements C4, C3 and factor H. Plasma exchanges and large-dose infusion therapy resulted in a resolution of hemolysis and recovery of renal function. Three recurrences were successfully treated by intensification of the plasma infusion treatment to intervals of 2 or 3 days. This patient showed good response to large doses of plasma infusions and her condition remained stable for 30 months with weekly plasma infusions (30 ml/kg). Long-term tolerance and efficacy of such intensive plasma therapy are still unknown. Reported secondary failure of plasma therapy in factor H deficiency warrants the search for alternative therapeutic approaches. PMID:18425537

  17. The cytolytic C5b-9 complement complex: feedback inhibition of complement activation.

    PubMed Central

    Bhakdi, S; Maillet, F; Muhly, M; Kazatchkine, M D

    1988-01-01

    We describe a regulatory function of the terminal cytolytic C5b-9 complex [C5b-9(m)] of human complement. Purified C5b-9(m) complexes isolated from target membranes, whether in solution or bound to liposomes, inhibited lysis of sensitized sheep erythrocytes by whole human serum in a dose-dependent manner. C9 was not required for the inhibitory function since C5b-7 and C5b-8 complexes isolated from membranes were also effective. No effect was found with the cytolytically inactive, fluid-phase SC5b-9 complex. However, tryptic modification of SC5b-9 conferred an inhibitory capacity to the complex, due probably to partial removal of the S protein. Experiments using purified components demonstrated that C5b-9(m) exerts a regulatory effect on the formation of the classical- and alternative-pathway C3 convertases and on the utilization of C5 by cell-bound C5 convertases. C5b-9(m) complexes were unable to inhibit the lysis of cells bearing C5b-7(m) by C8 and C9. Addition of C5b-9(m) to whole human serum abolished its bactericidal effect on the serum-sensitive Escherichia coli K-12 strain W 3110 and suppressed its hemolytic function on antibody-sensitized, autologous erythrocytes. Feedback inhibition by C5b-9(m) represents a biologically relevant mechanism through which complement may autoregulate its effector functions. Images PMID:3162317

  18. Complement deposition in autoimmune hemolytic anemia is a footprint for difficult-to-detect IgM autoantibodies

    PubMed Central

    Meulenbroek, Elisabeth M.; de Haas, Masja; Brouwer, Conny; Folman, Claudia; Zeerleder, Sacha S.; Wouters, Diana

    2015-01-01

    In autoimmune hemolytic anemia autoantibodies against erythrocytes lead to increased clearance of the erythrocytes, which in turn results in a potentially fatal hemolytic anemia. Depending on whether IgG or IgM antibodies are involved, response to therapy is different. Proper identification of the isotype of the anti-erythrocyte autoantibodies is, therefore, crucial. However, detection of IgM autoantibodies can be challenging. We, therefore, set out to improve the detection of anti-erythrocyte IgM. Direct detection using a flow cytometry-based approach did not yield satisfactory improvements. Next, we analyzed whether the presence of complement C3 on a patient’s erythrocytes could be used for indirect detection of anti-erythrocyte IgM. To this end, we fractionated patients’ sera by size exclusion chromatography and tested which fractions yielded complement deposition on erythrocytes. Strikingly, we found that all patients with C3 on their erythrocytes according to standard diagnostic tests had an IgM anti-erythrocyte component that could activate complement, even if no such autoantibody had been detected with any other test. This also included all tested patients with only IgG and C3 on their erythrocytes, who would previously have been classified as having an IgG-only mediated autoimmune hemolytic anemia. Depleting patients’ sera of either IgG or IgM and testing the remaining complement activation confirmed this result. In conclusion, complement activation in autoimmune hemolytic anemia is mostly IgM-mediated and the presence of covalent C3 on patients’ erythrocytes can be taken as a footprint of the presence of anti-erythrocyte IgM. Based on this finding, we propose a diagnostic workflow that will aid in choosing the optimal treatment strategy. PMID:26354757

  19. Peptide Inhibitor of Complement C1 (PIC1) Rapidly Inhibits Complement Activation after Intravascular Injection in Rats

    PubMed Central

    Sharp, Julia A.; Hair, Pamela S.; Pallera, Haree K.; Kumar, Parvathi S.; Mauriello, Clifford T.; Nyalwidhe, Julius O.; Phelps, Cody A.; Park, Dalnam; Thielens, Nicole M.; Pascal, Stephen M.; Chen, Waldon; Duffy, Diane M.; Lattanzio, Frank A.; Cunnion, Kenji M.; Krishna, Neel K.

    2015-01-01

    The complement system has been increasingly recognized to play a pivotal role in a variety of inflammatory and autoimmune diseases. Consequently, therapeutic modulators of the classical, lectin and alternative pathways of the complement system are currently in pre-clinical and clinical development. Our laboratory has identified a peptide that specifically inhibits the classical and lectin pathways of complement and is referred to as Peptide Inhibitor of Complement C1 (PIC1). In this study, we determined that the lead PIC1 variant demonstrates a salt-dependent binding to C1q, the initiator molecule of the classical pathway. Additionally, this peptide bound to the lectin pathway initiator molecule MBL as well as the ficolins H, M and L, suggesting a common mechanism of PIC1 inhibitory activity occurs via binding to the collagen-like tails of these collectin molecules. We further analyzed the effect of arginine and glutamic acid residue substitution on the complement inhibitory activity of our lead derivative in a hemolytic assay and found that the original sequence demonstrated superior inhibitory activity. To improve upon the solubility of the lead derivative, a pegylated, water soluble variant was developed, structurally characterized and demonstrated to inhibit complement activation in mouse plasma, as well as rat, non-human primate and human serum in vitro. After intravenous injection in rats, the pegylated derivative inhibited complement activation in the blood by 90% after 30 seconds, demonstrating extremely rapid function. Additionally, no adverse toxicological effects were observed in limited testing. Together these results show that PIC1 rapidly inhibits classical complement activation in vitro and in vivo and is functional for a variety of animal species, suggesting its utility in animal models of classical complement-mediated diseases. PMID:26196285

  20. Peptide Inhibitor of Complement C1 (PIC1) Rapidly Inhibits Complement Activation after Intravascular Injection in Rats.

    PubMed

    Sharp, Julia A; Hair, Pamela S; Pallera, Haree K; Kumar, Parvathi S; Mauriello, Clifford T; Nyalwidhe, Julius O; Phelps, Cody A; Park, Dalnam; Thielens, Nicole M; Pascal, Stephen M; Chen, Waldon; Duffy, Diane M; Lattanzio, Frank A; Cunnion, Kenji M; Krishna, Neel K

    2015-01-01

    The complement system has been increasingly recognized to play a pivotal role in a variety of inflammatory and autoimmune diseases. Consequently, therapeutic modulators of the classical, lectin and alternative pathways of the complement system are currently in pre-clinical and clinical development. Our laboratory has identified a peptide that specifically inhibits the classical and lectin pathways of complement and is referred to as Peptide Inhibitor of Complement C1 (PIC1). In this study, we determined that the lead PIC1 variant demonstrates a salt-dependent binding to C1q, the initiator molecule of the classical pathway. Additionally, this peptide bound to the lectin pathway initiator molecule MBL as well as the ficolins H, M and L, suggesting a common mechanism of PIC1 inhibitory activity occurs via binding to the collagen-like tails of these collectin molecules. We further analyzed the effect of arginine and glutamic acid residue substitution on the complement inhibitory activity of our lead derivative in a hemolytic assay and found that the original sequence demonstrated superior inhibitory activity. To improve upon the solubility of the lead derivative, a pegylated, water soluble variant was developed, structurally characterized and demonstrated to inhibit complement activation in mouse plasma, as well as rat, non-human primate and human serum in vitro. After intravenous injection in rats, the pegylated derivative inhibited complement activation in the blood by 90% after 30 seconds, demonstrating extremely rapid function. Additionally, no adverse toxicological effects were observed in limited testing. Together these results show that PIC1 rapidly inhibits classical complement activation in vitro and in vivo and is functional for a variety of animal species, suggesting its utility in animal models of classical complement-mediated diseases. PMID:26196285

  1. Complement Factor B Mutations in Atypical Hemolytic Uremic Syndrome—Disease-Relevant or Benign?

    PubMed Central

    Marinozzi, Maria Chiara; Vergoz, Laura; Rybkine, Tania; Ngo, Stephanie; Bettoni, Serena; Pashov, Anastas; Cayla, Mathieu; Tabarin, Fanny; Jablonski, Mathieu; Hue, Christophe; Smith, Richard J.; Noris, Marina; Halbwachs-Mecarelli, Lise; Donadelli, Roberta; Fremeaux-Bacchi, Veronique

    2014-01-01

    Atypical hemolytic uremic syndrome (aHUS) is a genetic ultrarare renal disease associated with overactivation of the alternative pathway of complement. Four gain-of-function mutations that form a hyperactive or deregulated C3 convertase have been identified in Factor B (FB) ligand binding sites. Here, we studied the functional consequences of 10 FB genetic changes recently identified from different aHUS cohorts. Using several tests for alternative C3 and C5 convertase formation and regulation, we identified two gain-of-function and potentially disease-relevant mutations that formed either an overactive convertase (M433I) or a convertase resistant to decay by FH (K298Q). One mutation (R178Q) produced a partially cleaved protein with no ligand binding or functional activity. Seven genetic changes led to near-normal or only slightly reduced ligand binding and functional activity compared with the most common polymorphism at position 7, R7. Notably, none of the algorithms used to predict the disease relevance of FB mutations agreed completely with the experimental data, suggesting that in silico approaches should be undertaken with caution. These data, combined with previously published results, suggest that 9 of 15 FB genetic changes identified in patients with aHUS are unrelated to disease pathogenesis. This study highlights that functional assessment of identified nucleotide changes in FB is mandatory to confirm disease association. PMID:24652797

  2. Combined Complement Gene Mutations in Atypical Hemolytic Uremic Syndrome Influence Clinical Phenotype

    PubMed Central

    Bresin, Elena; Rurali, Erica; Caprioli, Jessica; Sanchez-Corral, Pilar; Fremeaux-Bacchi, Veronique; Rodriguez de Cordoba, Santiago; Pinto, Sheila; Goodship, Timothy H.J.; Alberti, Marta; Ribes, David; Valoti, Elisabetta; Remuzzi, Giuseppe

    2013-01-01

    Several abnormalities in complement genes reportedly contribute to atypical hemolytic uremic syndrome (aHUS), but incomplete penetrance suggests that additional factors are necessary for the disease to manifest. Here, we sought to describe genotype–phenotype correlations among patients with combined mutations, defined as mutations in more than one complement gene. We screened 795 patients with aHUS and identified single mutations in 41% and combined mutations in 3%. Only 8%–10% of patients with mutations in CFH, C3, or CFB had combined mutations, whereas approximately 25% of patients with mutations in MCP or CFI had combined mutations. The concomitant presence of CFH and MCP risk haplotypes significantly increased disease penetrance in combined mutated carriers, with 73% penetrance among carriers with two risk haplotypes compared with 36% penetrance among carriers with zero or one risk haplotype. Among patients with CFH or CFI mutations, the presence of mutations in other genes did not modify prognosis; in contrast, 50% of patients with combined MCP mutation developed end stage renal failure within 3 years from onset compared with 19% of patients with an isolated MCP mutation. Patients with combined mutations achieved remission with plasma treatment similar to patients with single mutations. Kidney transplant outcomes were worse, however, for patients with combined MCP mutation compared with an isolated MCP mutation. In summary, these data suggest that genotyping for the risk haplotypes in CFH and MCP may help predict the risk of developing aHUS in unaffected carriers of mutations. Furthermore, screening patients with aHUS for all known disease-associated genes may inform decisions about kidney transplantation. PMID:23431077

  3. Complement inhibition in C3 glomerulopathy.

    PubMed

    Nester, Carla M; Smith, Richard J H

    2016-06-01

    C3 glomerulopathy (C3G) describes a spectrum of glomerular diseases defined by shared renal biopsy pathology: a predominance of C3 deposition on immunofluorescence with electron microscopy permitting disease sub-classification. Complement dysregulation underlies the observed pathology, a causal relationship that is supported by well described studies of genetic and acquired drivers of disease. In this article, we provide an overview of the features of C3G, including a discussion of disease definition and a review of the causal role of complement. We discuss molecular markers of disease and how biomarkers are informing our evolving understanding of underlying pathology. Research advances are laying the foundation for complement inhibition as a targeted approach to treatment of C3G. PMID:27402056

  4. Hemolytic complement activity and concentrations of its third component during maturation of the immune response in colostrum-deprived foals.

    PubMed

    Bernoco, M M; Liu, I K; Willits, N H

    1994-07-01

    Six foals were deprived of colostrum for the first 36 hours after birth and, instead, received reconstituted powdered milk. Five control foals suckled their dams naturally. Blood samples were obtained from all the foals after birth and at approximately weekly intervals until at least 5.5 months of age. Sera were analyzed for hemolytic complement activity, complement component C3, and correlating IgG concentration. Hemolytic complement (P = 0.0145) and C3 (P = 0.0002) values were significantly higher in colostrum-deprived foals (CDF) than in naturally nursed foals at 2 to 5 days of age. In addition, significantly (P = 0.0149) higher IgG concentration was found in CDF than in naturally nursed foals between 3 and 5.5 months of age. It was concluded that the observed high complement activity in CDF within 2 to 5 days of age may provide an alternative in immune defense for IgG-deprived foals after failure of colostral transfer. PMID:7978631

  5. Zinc Supplementation Inhibits Complement Activation in Age-Related Macular Degeneration

    PubMed Central

    Blom, Anna M.; Mohlin, Frida C.; den Hollander, Anneke I.; van de Ven, Johannes P. H.; van Huet, Ramon A. C.; Groenewoud, Joannes M. M.; Tian, Yuan; Berendschot, Tos T. J. M.; Lechanteur, Yara T. E.; Fauser, Sascha; de Bruijn, Chris; Daha, Mohamed R.; van der Wilt, Gert Jan; Hoyng, Carel B.; Klevering, B. Jeroen

    2014-01-01

    Age-related macular degeneration (AMD) is the leading cause of blindness in the Western world. AMD is a multifactorial disorder but complement-mediated inflammation at the level of the retina plays a pivotal role. Oral zinc supplementation can reduce the progression of AMD but the precise mechanism of this protective effect is as yet unclear. We investigated whether zinc supplementation directly affects the degree of complement activation in AMD and whether there is a relation between serum complement catabolism during zinc administration and the complement factor H (CFH) gene or the Age-Related Maculopathy susceptibility 2 (ARMS2) genotype. In this open-label clinical study, 72 randomly selected AMD patients in various stages of AMD received a daily supplement of 50 mg zinc sulphate and 1 mg cupric sulphate for three months. Serum complement catabolism–defined as the C3d/C3 ratio–was measured at baseline, throughout the three months of supplementation and after discontinuation of zinc administration. Additionally, downstream inhibition of complement catabolism was evaluated by measurement of anaphylatoxin C5a. Furthermore, we investigated the effect of zinc on complement activation in vitro. AMD patients with high levels of complement catabolism at baseline exhibited a steeper decline in serum complement activation (p<0.001) during the three month zinc supplementation period compared to patients with low complement levels. There was no significant association of change in complement catabolism and CFH and ARMS2 genotype. In vitro zinc sulphate directly inhibits complement catabolism in hemolytic assays and membrane attack complex (MAC) deposition on RPE cells. This study provides evidence that daily administration of 50 mg zinc sulphate can inhibit complement catabolism in AMD patients with increased complement activation. This could explain part of the mechanism by which zinc slows AMD progression. Trial Registration The Netherlands National Trial Register

  6. The Alternative Pathway of Complement and the Evolving Clinical-Pathophysiological Spectrum of Atypical Hemolytic Uremic Syndrome.

    PubMed

    Berger, Bruce E

    2016-08-01

    Complement-mediated atypical hemolytic uremic syndrome (aHUS) comprises approximately 90% of cases of aHUS, and results from dysregulation of endothelial-anchored complement activation with resultant endothelial damage. The discovery of biomarker ADAMTS13 has enabled a more accurate diagnosis of thrombotic thrombocytopenic purpura (TTP) and an appreciation of overlapping clinical features of TTP and aHUS. Given our present understanding of the pathogenic pathways involved in aHUS, it is unlikely that a specific test will be developed. Rather the use of biomarker data, complement functional analyses, genomic analyses and clinical presentation will be required to diagnose aHUS. This approach would serve to clarify whether a thrombotic microangiopathy present in a complement-amplifying condition arises from the unmasking of a genetically driven aHUS versus a time-limited complement storm-mediated aHUS due to direct endothelial damage in which no genetic predisposition is present. Although both scenarios result in the phenotypic expression of aHUS and involve the alternate pathway of complement activation, long-term management would differ. PMID:27524217

  7. The molecular and structural bases for the association of complement C3 mutations with atypical hemolytic uremic syndrome

    PubMed Central

    Martínez-Barricarte, Rubén; Heurich, Meike; López-Perrote, Andrés; Tortajada, Agustin; Pinto, Sheila; López-Trascasa, Margarita; Sánchez-Corral, Pilar; Morgan, B. Paul; Llorca, Oscar; Harris, Claire L.; Rodríguez de Córdoba, Santiago

    2015-01-01

    Atypical hemolytic uremic syndrome (aHUS) associates with complement dysregulation caused by mutations and polymorphisms in complement activators and regulators. However, the reasons why some mutations in complement proteins predispose to aHUS are poorly understood. Here, we have investigated the functional consequences of three aHUS-associated mutations in C3, R592W, R161W and I1157T. First, we provide evidence that penetrance and disease severity for these mutations is modulated by inheritance of documented “risk” haplotypes as has been observed with mutations in other complement genes. Next, we show that all three mutations markedly reduce the efficiency of factor I-mediated C3b cleavage when catalyzed by membrane cofactor protein (MCP), but not when catalyzed by factor H. Biacore analysis showed that each mutant C3b bound sMCP (recombinant soluble MCP; CD46) at reduced affinity, providing a molecular basis for its reduced cofactor activity. Lastly, we show by electron microscopy structural analysis a displacement of the TED domain from the MG ring in C3b in two of the C3 mutants that explains these defects in regulation. As a whole our data suggest that aHUS-associated mutations in C3 selectively affect regulation of complement on surfaces and provide a structural framework to predict the functional consequences of the C3 genetic variants found in patients. PMID:25879158

  8. Complement Activation and Inhibition in Wound Healing

    PubMed Central

    Cazander, Gwendolyn; Jukema, Gerrolt N.; Nibbering, Peter H.

    2012-01-01

    Complement activation is needed to restore tissue injury; however, inappropriate activation of complement, as seen in chronic wounds can cause cell death and enhance inflammation, thus contributing to further injury and impaired wound healing. Therefore, attenuation of complement activation by specific inhibitors is considered as an innovative wound care strategy. Currently, the effects of several complement inhibitors, for example, the C3 inhibitor compstatin and several C1 and C5 inhibitors, are under investigation in patients with complement-mediated diseases. Although (pre)clinical research into the effects of these complement inhibitors on wound healing is limited, available data indicate that reduction of complement activation can improve wound healing. Moreover, medicine may take advantage of safe and effective agents that are produced by various microorganisms, symbionts, for example, medicinal maggots, and plants to attenuate complement activation. To conclude, for the development of new wound care strategies, (pre)clinical studies into the roles of complement and the effects of application of complement inhibitors in wound healing are required. PMID:23346185

  9. Disturbed sialic acid recognition on endothelial cells and platelets in complement attack causes atypical hemolytic uremic syndrome.

    PubMed

    Hyvärinen, Satu; Meri, Seppo; Jokiranta, T Sakari

    2016-06-01

    Uncontrolled activation of the complement system against endothelial and blood cells is central to the pathogenesis of atypical hemolytic uremic syndrome (aHUS). aHUS patients frequently carry mutations in the inhibitory complement regulator factor H (FH). Mutations cluster in domains 19 and 20 (FH19-20), which are critical for recognizing self surfaces. On endothelial cells, binding of FH is generally attributed to heparan sulfate. This theory, however, is questioned by the puzzling observation that some aHUS-associated mutations markedly enhance FH binding to heparin and endothelial cells. In this article, we show that, instead of disturbed heparin interactions, the impaired ability of C-terminal mutant FH molecules to recognize sialic acid in the context of surface-bound C3b explains their pathogenicity. By using recombinant FH19-20 as a competitor for FH and measuring erythrocyte lysis and deposition of complement C3b and C5b-9 on endothelial cells and platelets, we now show that several aHUS-associated mutations, which have been predicted to impair FH19-20 binding to sialic acid, prevent FH19-20 from antagonizing FH function on cells. When sialic acid was removed, the wild-type FH19-20 also lost its ability to interfere with FH function on cells. These results indicate that sialic acid is critical for FH-mediated complement regulation on erythrocytes, endothelial cells, and platelets. The inability of C-terminal mutant FH molecules to simultaneously bind sialic acid and C3b on cells provides a unifying explanation for their association with aHUS. Proper formation of FH-sialic acid-C3b complexes on surfaces exposed to plasma is essential for preventing cell damage and thrombogenesis characteristic of aHUS. PMID:27006390

  10. Human Astrovirus Coat Protein Inhibits Serum Complement Activation via C1, the First Component of the Classical Pathway▿

    PubMed Central

    Bonaparte, Rheba S.; Hair, Pamela S.; Banthia, Deepa; Marshall, Dawn M.; Cunnion, Kenji M.; Krishna, Neel K.

    2008-01-01

    Human astroviruses (HAstVs) belong to a family of nonenveloped, icosahedral RNA viruses that cause noninflammatory gastroenteritis, predominantly in infants. Eight HAstV serotypes have been identified, with a worldwide distribution. While the HAstVs represent a significant public health concern, very little is known about the pathogenesis of and host immune response to these viruses. Here we demonstrate that HAstV type 1 (HAstV-1) virions, specifically the viral coat protein (CP), suppress the complement system, a fundamental component of the innate immune response in vertebrates. HAstV-1 virions and purified CP both suppress hemolytic complement activity. Hemolytic assays utilizing sera depleted of individual complement factors as well as adding back purified factors demonstrated that HAstV CP suppresses classical pathway activation at the first component, C1. HAstV-1 CP bound the A chain of C1q and inhibited serum complement activation, resulting in decreased C4b, iC3b, and terminal C5b-9 formation. Inhibition of complement activation was also demonstrated for HAstV serotypes 2 to 4, suggesting that this phenomenon is a general feature of these human pathogens. Since complement is a major contributor to the initiation and amplification of inflammation, the observed CP-mediated inhibition of complement activity may contribute to the lack of inflammation associated with astrovirus-induced gastroenteritis. Although diverse mechanisms of inhibition of complement activation have been described for many enveloped animal viruses, this is the first report of a nonenveloped icosahedral virus CP inhibiting classical pathway activation at C1. PMID:17959658

  11. Shiga Toxin Promotes Podocyte Injury in Experimental Hemolytic Uremic Syndrome via Activation of the Alternative Pathway of Complement

    PubMed Central

    Locatelli, Monica; Buelli, Simona; Pezzotta, Anna; Corna, Daniela; Perico, Luca; Tomasoni, Susanna; Rottoli, Daniela; Rizzo, Paola; Conti, Debora; Thurman, Joshua M.; Remuzzi, Giuseppe; Zoja, Carlamaria

    2014-01-01

    Shiga toxin (Stx)–producing Escherichia coli is the offending agent of postdiarrhea-associated hemolytic uremic syndrome (HUS), a disorder of glomerular ischemic damage and widespread microvascular thrombosis. We previously documented that Stx induces glomerular complement activation, generating C3a responsible for microvascular thrombosis in experimental HUS. Here, we show that the presence of C3 deposits on podocytes is associated with podocyte damage and loss in HUS mice generated by the coinjection of Stx2 and LPS. Because podocyte adhesion to the glomerular basement membrane is mediated by integrins, the relevance of integrin-linked kinase (ILK) signals in podocyte dysfunction was evaluated. Podocyte expression of ILK increased after the injection of Stx2/LPS and preceded the upregulation of Snail and downregulation of nephrin and α-actinin-4. Factor B deficiency or pretreatment with an inhibitory antibody to factor B protected mice against Stx2/LPS-induced podocyte dysregulation. Similarly, pretreatment with a C3a receptor antagonist limited podocyte loss and changes in ILK, Snail, and α-actinin-4 expression. In cultured podocytes, treatment with C3a reduced α-actinin-4 expression and promoted ILK-dependent nuclear expression of Snail and cell motility. These results suggest that Stx-induced activation of the alternative pathway of complement and generation of C3a promotes ILK signaling, leading to podocyte dysfunction and loss in Stx-HUS. PMID:24578132

  12. Complement Inhibition for Prevention and Treatment of Antibody-Mediated Rejection in Renal Allograft Recipients.

    PubMed

    Jordan, S C; Choi, J; Kahwaji, J; Vo, A

    2016-04-01

    Therapeutic interventions aimed at the human complement system are recognized as potentially important strategies for the treatment of inflammatory and autoimmune diseases because there is often evidence of complement-mediated injury according to pathologic assessments. In addition, there are a large number of potential targets, both soluble and cell bound, that might offer potential for new drug development, but progress in this area has met with significant challenges. Currently, 2 drugs are approved aimed at inhibition of complement activation. The first option is eculizumab (anti-C5), which is approved for the treatment of paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome. Eculizumab has also been studied in human transplantation for the treatment and prevention of antibody-mediated rejection (ABMR). Initial data from uncontrolled studies suggested a significant benefit of eculizumab for the prevention of ABMR in highly HLA-sensitized patients, but a subsequent randomized, placebo-controlled trial failed to meet its primary endpoint. Anecdotal data, primarily from case studies, showed benefits in treating complement-mediated ABMR. A second approved complement-inhibiting therapy is C1 esterase inhibitor (C1-INH), which is approved for use in patients with hereditary angioedema, a condition caused by mutations in the gene that codes for C1-INH. A recent placebo-controlled trial of C1-INH for prevention of ABMR in HLA-sensitized patients found that the drug was safe, with evidence for inhibition of systemic complement activation and complement-activating donor-specific antibodies. Other drugs are now under development. PMID:27234741

  13. Complement inhibition: a promising concept for cancer treatment

    PubMed Central

    Pio, Ruben; Ajona, Daniel; Lambris, John D.

    2013-01-01

    For decades, complement has been recognized as an effector arm of the immune system that contributes to the destruction of tumor cells. In fact, many therapeutic strategies have been proposed that are based on the intensification of complement-mediated responses against tumors. However, recent studies have challenged this paradigm by demonstrating a tumor-promoting role for complement. Cancer cells seem to be able to establish a convenient balance between complement activation and inhibition, taking advantage of complement initiation without suffering its deleterious effects. Complement activation may support chronic inflammation, promote an immunosuppressive microenvironment, induce angiogenesis, and activate cancer-related signaling pathways. In this context, inhibition of complement activation would be a therapeutic option for treating cancer. This concept is relatively novel and deserves closer attention. In this paper, we will summarize the mechanisms of complement activation on cancer cells, the cancer-promoting effect of complement initiation, and the rationale behind the use of complement inhibition as a therapeutic strategy against cancer. PMID:23706991

  14. ATYPICAL HEMOLYTIC UREMIC SYNDROME AND GENETIC ABERRATIONS IN THE COMPLEMENT FACTOR H RELATED 5 GENE

    PubMed Central

    Westra, Dineke; Vernon, Katherine A.; Volokhina, Elena B.; Pickering, Matthew C.; van de Kar, Nicole C.A.J.; van den Heuvel, Lambert P.

    2012-01-01

    Atypical HUS (aHUS) is a severe renal disorder that is associated with mutations in the genes encoding proteins of the complement alternative pathway. Previously, we identified pathogenic variations in genes encoding complement regulators (CFH, CFI, and MCP) in our aHUS cohort. In this study, we screened for mutations in the alternative pathway regulator CFHR5 in 65 aHUS patients by means of PCR on genomic DNA and sequence analysis. Potential pathogenicity of genetic alterations was determined by published data on CFHR5 variants, evolutionary conservation, and in silico mutation prediction programs. Detection of serum CFHR5 was performed by western blot analysis and ELISA. A potentially pathogenic sequence variation was found in CFHR5 in three patients (4.6%). All variations were located in SCRs that might be involved in binding to C3b, heparin, or CRP. The identified CFHR5 mutations require functional studies to determine their relevance to aHUS, but they might be candidates for an altered genetic profile predisposing to the disease. PMID:22622361

  15. Trichinella spiralis Paramyosin Binds Human Complement C1q and Inhibits Classical Complement Activation

    PubMed Central

    Sun, Ran; Zhao, Xi; Wang, Zixia; Yang, Jing; Zhao, Limei; Zhan, Bin; Zhu, Xinping

    2015-01-01

    Background Trichinella spiralis expresses paramyosin (Ts-Pmy) as a defense mechanism. Ts-Pmy is a functional protein with binding activity to human complement C8 and C9 and thus plays a role in evading the attack of the host’s immune system. In the present study, the binding activity of Ts-Pmy to human complement C1q and its ability to inhibit classical complement activation were investigated. Methods and Findings The binding of recombinant and natural Ts-Pmy to human C1q were determined by ELISA, Far Western blotting and immunoprecipitation, respectively. Binding of recombinant Ts-Pmy (rTs-Pmy) to C1q inhibited C1q binding to IgM and consequently inhibited C3 deposition. The lysis of antibody-sensitized erythrocytes (EAs) elicited by the classical complement pathway was also inhibited in the presence of rTs-Pmy. In addition to inhibiting classical complement activation, rTs-Pmy also suppressed C1q binding to THP-1-derived macrophages, thereby reducing C1q-induced macrophages migration. Conclusion Our results suggest that T. spiralis paramyosin plays an important role in immune evasion by interfering with complement activation through binding to C1q in addition to C8 and C9. PMID:26720603

  16. A De Novo Deletion in the Regulators of Complement Activation Cluster Producing a Hybrid Complement Factor H/Complement Factor H-Related 3 Gene in Atypical Hemolytic Uremic Syndrome.

    PubMed

    Challis, Rachel C; Araujo, Geisilaine S R; Wong, Edwin K S; Anderson, Holly E; Awan, Atif; Dorman, Anthony M; Waldron, Mary; Wilson, Valerie; Brocklebank, Vicky; Strain, Lisa; Morgan, B Paul; Harris, Claire L; Marchbank, Kevin J; Goodship, Timothy H J; Kavanagh, David

    2016-06-01

    The regulators of complement activation cluster at chromosome 1q32 contains the complement factor H (CFH) and five complement factor H-related (CFHR) genes. This area of the genome arose from several large genomic duplications, and these low-copy repeats can cause genome instability in this region. Genomic disorders affecting these genes have been described in atypical hemolytic uremic syndrome, arising commonly through nonallelic homologous recombination. We describe a novel CFH/CFHR3 hybrid gene secondary to a de novo 6.3-kb deletion that arose through microhomology-mediated end joining rather than nonallelic homologous recombination. We confirmed a transcript from this hybrid gene and showed a secreted protein product that lacks the recognition domain of factor H and exhibits impaired cell surface complement regulation. The fact that the formation of this hybrid gene arose as a de novo event suggests that this cluster is a dynamic area of the genome in which additional genomic disorders may arise. PMID:26490391

  17. Mesenchymal stem cells inhibit complement activation by secreting factor H.

    PubMed

    Tu, Zhidan; Li, Qing; Bu, Hong; Lin, Feng

    2010-11-01

    Mesenchymal stem cells (MSCs) possess potent and broad immunosuppressive capabilities, and have shown promise in clinical trials treating many inflammatory diseases. Previous studies have found that MSCs inhibit dendritic cell, T-cell, and B-cell activities in the adaptive immunity; however, whether MSCs inhibit complement in the innate immunity, and if so, by which mechanism, have not been established. In this report, we found that MSCs constitutively secrete factor H, which potently inhibits complement activation. Depletion of factor H in the MSC-conditioned serum-free media abolishes their complement inhibitory activities. In addition, production of factor H by MSCs is augmented by inflammatory cytokines TNF-α and interferon-γ (IFN-γ) in dose- and time-dependent manners, while IL-6 does not have a significant effect. Furthermore, the factor H production from MSCs is significantly suppressed by the prostaglandin E2 (PGE2) synthesis inhibitor indomethacin and the indoleamine 2,3-dioxygenase (IDO) inhibitor 1-methyl-d-tryptophan (1-MT), both of which inhibitors are known to efficiently dampen MSCs immunosuppressive activity. These results indicate that MSCs inhibit complement activation by producing factor H, which could be another mechanism underlying MSCs broad immunosuppressive capabilities. PMID:20163251

  18. Complement

    MedlinePlus

    ... the suspected disease are done first. C3 and C4 are the complement components measured most often. A ... normal levels of the complement proteins C3 and C4 . Complement activity varies throughout the body. For example, ...

  19. Potent inhibition of the classical pathway of complement by a novel C1q-binding peptide derived from the human astrovirus coat protein.

    PubMed

    Gronemus, Jenny Q; Hair, Pamela S; Crawford, Katrina B; Nyalwidhe, Julius O; Cunnion, Kenji M; Krishna, Neel K

    2010-01-01

    Previous work from our laboratories has demonstrated that purified, recombinant human astrovirus coat protein (HAstV CP) binds C1q and mannose-binding lectin (MBL) inhibiting activation of the classical and lectin pathways of complement, respectively. Analysis of the 787 amino acid CP molecule revealed that residues 79-139 share limited sequence homology with human neutrophil defensin-1 (HNP-1), a molecule previously demonstrated to bind C1q and MBL, inhibiting activation of the classical and lectin pathways of complement, respectively. A 30 amino acid peptide derived from this region of the CP molecule competitively inhibited the binding of wild-type CP to C1q. The parent peptide and various derivatives were subsequently assayed for C1q binding, inhibition of C1 and C4 activation as well as suppression of complement activation in hemolytic assays. The parent peptide and several derivatives inhibited complement activation in these functional assays to varying degrees. One peptide derivative in particular (E23A) displayed superior inhibition of complement activation in multiple assays of classical complement pathway activation. Further analysis revealed homology to a plant defensin allowing development of a proposed structural model for E23A. Based upon these findings, we hypothesize that further rationale optimization of E23A may result in a promising therapeutic inhibitor for the treatment of inflammatory and autoimmune diseases in which dysregulated activation of the classical and lectin pathways of complement contribute to pathogenesis. PMID:20728940

  20. Structural basis for therapeutic inhibition of complement C5.

    PubMed

    Jore, Matthijs M; Johnson, Steven; Sheppard, Devon; Barber, Natalie M; Li, Yang I; Nunn, Miles A; Elmlund, Hans; Lea, Susan M

    2016-05-01

    Activation of complement C5 generates the potent anaphylatoxin C5a and leads to pathogen lysis, inflammation and cell damage. The therapeutic potential of C5 inhibition has been demonstrated by eculizumab, one of the world's most expensive drugs. However, the mechanism of C5 activation by C5 convertases remains elusive, thus limiting development of therapeutics. Here we identify and characterize a new protein family of tick-derived C5 inhibitors. Structures of C5 in complex with the new inhibitors, the phase I and phase II inhibitor OmCI, or an eculizumab Fab reveal three distinct binding sites on C5 that all prevent activation of C5. The positions of the inhibitor-binding sites and the ability of all three C5-inhibitor complexes to competitively inhibit the C5 convertase conflict with earlier steric-inhibition models, thus suggesting that a priming event is needed for activation. PMID:27018802

  1. Streptomyces-derived actinomycin D inhibits biofilm formation by Staphylococcus aureus and its hemolytic activity.

    PubMed

    Lee, Jin-Hyung; Kim, Yong-Guy; Lee, Kayeon; Kim, Chang-Jin; Park, Dong-Jin; Ju, Yoonjung; Lee, Jae-Chan; Wood, Thomas K; Lee, Jintae

    2016-01-01

    Staphylococcus aureus is a versatile human pathogen that produces diverse virulence factors, and its biofilm cells are difficult to eradicate due to their inherent ability to tolerate antibiotics. The anti-biofilm activities of the spent media of 252 diverse endophytic microorganisms were investigated using three S. aureus strains. An attempt was made to identify anti-biofilm compounds in active spent media and to assess their anti-hemolytic activities and hydrophobicities in order to investigate action mechanisms. Unlike other antibiotics, actinomycin D (0.5 μg ml(-1)) from Streptomyces parvulus significantly inhibited biofilm formation by all three S. aureus strains. Actinomycin D inhibited slime production in S. aureus and it inhibited hemolysis by S. aureus and caused S. aureus cells to become less hydrophobic, thus supporting its anti-biofilm effect. In addition, surface coatings containing actinomycin D prevented S. aureus biofilm formation on glass surfaces. Given these results, FDA-approved actinomycin D warrants further attention as a potential antivirulence agent against S. aureus infections. PMID:26785934

  2. The IgG-specific endoglycosidase EndoS inhibits both cellular and complement-mediated autoimmune hemolysis

    PubMed Central

    Briceño, Juana G.; Baudino, Lucie; Lood, Christian; Olsson, Martin L.; Izui, Shozo; Collin, Mattias

    2010-01-01

    EndoS from Streptococcus pyogenes is an immunomodulating enzyme that specifically hydrolyzes glycans from human immunoglobulin G and thereby affects antibody effector functions. Autoimmune hemolytic anemia is caused by antibody-mediated red blood cell (RBC) destruction and often resists treatment with corticosteroids that also cause frequent adverse effects. We show here that anti-RhD (anti-D) and rabbit anti–human-RBC antibodies (anti-RBC) mediated destruction of RBC, ie, phagocytosis, complement activation, and hemolysis in vitro and in vivo was inhibited by EndoS. Phagocytosis by monocytes in vitro was inhibited by pretreatment of anti-D with EndoS before sensitization of RBCs and abrogated by direct addition of EndoS to blood containing sensitized RBCs. The toxic effects of monocytes stimulated with anti-D–sensitized RBCs, as measured by interleukin-8 secretion and oxygen metabolite production, was restrained by EndoS. Agglutination of RBCs and complement-mediated hemolysis in vitro in whole human blood caused by rabbit anti-RBCs was inhibited by EndoS. Development of anemia in mice caused by a murine anti-RBC immunoglobulin G2a monoclonal autoantibody and complement activation and erythrophagocytosis by Kupffer cells in the liver were reduced by EndoS. Our data indicate that EndoS is a potential therapeutic agent that might be evaluated as an alternative to current treatment regimens against antibody-mediated destruction of RBCs. PMID:20357243

  3. Complement inhibitors to treat IgM-mediated autoimmune hemolysis.

    PubMed

    Wouters, Diana; Zeerleder, Sacha

    2015-11-01

    Complement activation in autoimmune hemolytic anemia may exacerbate extravascular hemolysis and may occasionally result in intravascular hemolysis. IgM autoantibodies as characteristically found in cold autoantibody autoimmune hemolytic anemia, in cold agglutinin disease but also in a considerable percentage of patients with warm autoantibodies are very likely to activate complement in vivo. Therapy of IgM-mediated autoimmune hemolytic anemia mainly aims to decrease autoantibody production. However, most of these treatments require time to become effective and will not stop immediate ongoing complement-mediated hemolysis nor prevent hemolysis of transfused red blood cells. Therefore pharmacological inhibition of the complement system might be a suitable approach to halt or at least attenuate ongoing hemolysis and improve the recovery of red blood cell transfusion in autoimmune hemolytic anemia. In recent years, several complement inhibitors have become available in the clinic, some of them with proven efficacy in autoimmune hemolytic anemia. In the present review, we give a short introduction on the pathogenesis of autoimmune hemolytic anemia, followed by an overview on the complement system with a special focus on its regulation. Finally, we will discuss complement inhibitors with regard to their potential efficacy to halt or attenuate hemolysis in complement-mediated autoimmune hemolytic anemia. PMID:26521297

  4. Complement inhibitors to treat IgM-mediated autoimmune hemolysis

    PubMed Central

    Wouters, Diana; Zeerleder, Sacha

    2015-01-01

    Complement activation in autoimmune hemolytic anemia may exacerbate extravascular hemolysis and may occasionally result in intravascular hemolysis. IgM autoantibodies as characteristically found in cold autoantibody autoimmune hemolytic anemia, in cold agglutinin disease but also in a considerable percentage of patients with warm autoantibodies are very likely to activate complement in vivo. Therapy of IgM-mediated autoimmune hemolytic anemia mainly aims to decrease autoantibody production. However, most of these treatments require time to become effective and will not stop immediate ongoing complement-mediated hemolysis nor prevent hemolysis of transfused red blood cells. Therefore pharmacological inhibition of the complement system might be a suitable approach to halt or at least attenuate ongoing hemolysis and improve the recovery of red blood cell transfusion in autoimmune hemolytic anemia. In recent years, several complement inhibitors have become available in the clinic, some of them with proven efficacy in autoimmune hemolytic anemia. In the present review, we give a short introduction on the pathogenesis of autoimmune hemolytic anemia, followed by an overview on the complement system with a special focus on its regulation. Finally, we will discuss complement inhibitors with regard to their potential efficacy to halt or attenuate hemolysis in complement-mediated autoimmune hemolytic anemia. PMID:26521297

  5. Degradation of Complement 3 by Streptococcal Pyrogenic Exotoxin B Inhibits Complement Activation and Neutrophil Opsonophagocytosis▿

    PubMed Central

    Kuo, Chih-Feng; Lin, Yee-Shin; Chuang, Woei-Jer; Wu, Jiunn-Jong; Tsao, Nina

    2008-01-01

    Streptococcal pyrogenic exotoxin B (SPE B), a cysteine protease, is an important virulence factor in group A streptococcus (GAS) infection. The inhibition of phagocytic activity by SPE B may help prevent bacteria from being ingested. In this study, we examined the mechanism SPE B uses to enable bacteria to resist opsonophagocytosis. Using an enzyme-linked immunosorbent assay, we found that SPE B-treated serum impaired the activation of the classical, the lectin, and the alternative complement pathways. In contrast, C192S, a SPE B mutant lacking protease activity, had no effect on complement activation. Further study showed that cleavage of serum C3 by SPE B, but not C192S, blocked zymosan-induced production of reactive oxygen species in neutrophils as a result of decreased deposition of C3 fragments on the zymosan surface. Reconstitution of C3 into SPE B-treated serum unblocked zymosan-mediated neutrophil activation dose dependently. SPE B-treated, but not C192S-treated, serum also impaired opsonization of C3 fragments on the surface of GAS strain A20. Moreover, the amount of C3 fragments on the A20 cell surface, a SPE B-producing strain, was less than that on its isogenic mutant strain, SW507, after opsonization with normal serum. A20 opsonized with SPE B-treated serum was more resistant to neutrophil killing than A20 opsonized with normal serum, and SPE B-mediated resistance was C3 dependent. These results suggest a novel SPE B mechanism, one which degrades serum C3 and enables GAS to resist complement damage and opsonophagocytosis. PMID:18174338

  6. Hemolytic anemia

    MedlinePlus

    Anemia - hemolytic ... bones that helps form all blood cells. Hemolytic anemia occurs when the bone marrow isn't making ... destroyed. There are several possible causes of hemolytic anemia. Red blood cells may be destroyed due to: ...

  7. Hemolytic Anemia

    MedlinePlus

    ... from the NHLBI on Twitter. What Is Hemolytic Anemia? Hemolytic anemia (HEE-moh-lit-ick uh-NEE-me-uh) ... blood cells to replace them. However, in hemolytic anemia, the bone marrow can't make red blood ...

  8. Hemolytic anemia

    MedlinePlus

    Anemia - hemolytic ... Hemolytic anemia occurs when the bone marrow is unable to replace the red blood cells that are being destroyed. Immune hemolytic anemia occurs when the immune system mistakenly sees your ...

  9. Oversulfated chondroitin sulfate inhibits the complement classical pathway by potentiating C1 inhibitor.

    PubMed

    Zhou, Zhao-Hua; Rajabi, Mohsen; Chen, Trina; Karnaukhova, Elena; Kozlowski, Steven

    2012-01-01

    Oversulfated chondroitin sulfate (OSCS) has become the subject of multidisciplinary investigation as a non-traditional contaminant in the heparin therapeutic preparations that were linked to severe adverse events. In this study, it was found that OSCS inhibited complement fixation on bacteria and bacterial lysis mediated by the complement classical pathway. The inhibition of complement by OSCS is not due to interference with antibody/antigen interaction or due to consumption of C3 associated with FXII-dependent contact system activation. However, OSCS complement inhibition is dependent on C1 inhibitor (C1inh) since the depletion of C1inh from either normal or FXII-deficient complement plasma prevents OSCS inhibition of complement activity. Surface plasmon resonance measurements revealed that immobilized C1inhibitor bound greater than 5-fold more C1s in the presence of OSCS than in presence of heparin. Although heparin can also inhibit complement, OSCS and OSCS contaminated heparin are more potent inhibitors of complement. Furthermore, polysulfated glycosaminoglycan (PSGAG), an anti-inflammatory veterinary medicine with a similar structure to OSCS, also inhibited complement in the plasma of dogs and farm animals. This study provides a new insight that in addition to the FXII-dependent activation of contact system, oversulfated and polysulfated chondroitin-sulfate can inhibit complement activity by potentiating the classical complement pathway regulator C1inh. This effect on C1inh may play a role in inhibiting inflammation as well as impacting bacterial clearance. PMID:23077587

  10. Engineering of human complement component C3 for catalytic inhibition of complement.

    PubMed

    Kölln, Johanna; Bredehorst, Reinhard; Spillner, Edzard

    2005-04-15

    As a novel therapeutic approach in complement-mediated pathologies, we recently developed a human C3 derivative capable of obliterating functional complement by a catalytic, non-inhibitory mechanism. In this derivative, the C-terminal region of hC3 was substituted by a 275 amino acid sequence derived from the corresponding sequence of cobra venom factor (CVF), a complement-activating C3b homologue from snake venom. In this study, we replaced shorter C-terminal sequences of hC3 by corresponding CVF sequences to further reduce potential immunogenicity and to identify domains essential for the formation of functionally stable C3 convertases. In one of these derivatives that is still capable of obliterating functional complement in vitro, the non-human portion could be reduced to a small domain located in the C-terminus of different complement proteins. This conserved NTR/C345C motif is known to be involved in assembly of different convertases of the complement system. These results suggest a major role of the C345C domain in the regulation of the half-life of the C3 convertase. Moreover, its overall identity of 96% to human C3 renders this derivative a promising candidate for therapeutic intervention in complement-mediated pathologies. PMID:15790508

  11. Disease Recurrence After Early Discontinuation of Eculizumab in a Patient With Atypical Hemolytic Uremic Syndrome With Complement C3 I1157T Mutation.

    PubMed

    Toyoda, Hidemi; Wada, Hideo; Miyata, Toshiyuki; Amano, Keishiro; Kihira, Kentaro; Iwamoto, Shotaro; Hirayama, Masahiro; Komada, Yoshihiro

    2016-04-01

    Eculizumab, terminal complement inhibitor, has become the frontline treatment for atypical hemolytic uremic syndrome (aHUS). However, the optimal treatment schedule has not yet been established. We describe here an aHUS patient with a mutation of C3 I1157T who achieved remission with eculizumab and suffered a recurrence after eculizumab discontinuation, a clinical situation that has not been previously described in patients with C3 mutation. A 9-year-old male experienced an onset of aHUS after viral gastroenteritis and was treated with hemodialysis. At 13 years of age he developed bacterial enterocolitis due to Campylobacter jejuni and experienced a recurrence of aHUS. Eculizumab was initiated on day 4 after disease onset resulting in recovering laboratory parameters. The patient received eculizumab for 5 months before its discontinuation. Second relapse induced by bacterial pharyngitis was confirmed 4 months after eculizumab discontinuation and prompt eculizumab reinitiation resulted in rapid remission. The patients carrying mutations in CFH or C3 have a high frequency of relapse and worse prognosis. More than 50% of aHUS relapses occurred during the first year after the onset. Therefore, long-term treatment with eculizumab is appropriate in patients with aHUS who have experienced a relapse or have mutations associated with poor prognosis. PMID:26840081

  12. Calcium-chelating alizarin and other anthraquinones inhibit biofilm formation and the hemolytic activity of Staphylococcus aureus

    PubMed Central

    Lee, Jin-Hyung; Kim, Yong-Guy; Yong Ryu, Shi; Lee, Jintae

    2016-01-01

    Staphylococcal biofilms are problematic and play a critical role in the persistence of chronic infections because of their abilities to tolerate antimicrobial agents. Thus, the inhibitions of biofilm formation and/or toxin production are viewed as alternative means of controlling Staphylococcus aureus infections. Here, the antibiofilm activities of 560 purified phytochemicals were examined. Alizarin at 10 μg/ml was found to efficiently inhibit biofilm formation by three S. aureus strains and a Staphylococcus epidermidis strain. In addition, two other anthraquinones purpurin and quinalizarin were found to have antibiofilm activity. Binding of Ca2+ by alizarin decreased S. aureus biofilm formation and a calcium-specific chelating agent suppressed the effect of calcium. These three anthraquinones also markedly inhibited the hemolytic activity of S. aureus, and in-line with their antibiofilm activities, increased cell aggregation. A chemical structure-activity relationship study revealed that two hydroxyl units at the C-1 and C-2 positions of anthraquinone play important roles in antibiofilm and anti-hemolytic activities. Transcriptional analyses showed that alizarin repressed the α-hemolysin hla gene, biofilm-related genes (psmα, rbf, and spa), and modulated the expressions of cid/lrg genes (the holin/antiholin system). These findings suggest anthraquinones, especially alizarin, are potentially useful for controlling biofilm formation and the virulence of S. aureus. PMID:26763935

  13. Calcium-chelating alizarin and other anthraquinones inhibit biofilm formation and the hemolytic activity of Staphylococcus aureus.

    PubMed

    Lee, Jin-Hyung; Kim, Yong-Guy; Yong Ryu, Shi; Lee, Jintae

    2016-01-01

    Staphylococcal biofilms are problematic and play a critical role in the persistence of chronic infections because of their abilities to tolerate antimicrobial agents. Thus, the inhibitions of biofilm formation and/or toxin production are viewed as alternative means of controlling Staphylococcus aureus infections. Here, the antibiofilm activities of 560 purified phytochemicals were examined. Alizarin at 10 μg/ml was found to efficiently inhibit biofilm formation by three S. aureus strains and a Staphylococcus epidermidis strain. In addition, two other anthraquinones purpurin and quinalizarin were found to have antibiofilm activity. Binding of Ca(2+) by alizarin decreased S. aureus biofilm formation and a calcium-specific chelating agent suppressed the effect of calcium. These three anthraquinones also markedly inhibited the hemolytic activity of S. aureus, and in-line with their antibiofilm activities, increased cell aggregation. A chemical structure-activity relationship study revealed that two hydroxyl units at the C-1 and C-2 positions of anthraquinone play important roles in antibiofilm and anti-hemolytic activities. Transcriptional analyses showed that alizarin repressed the α-hemolysin hla gene, biofilm-related genes (psmα, rbf, and spa), and modulated the expressions of cid/lrg genes (the holin/antiholin system). These findings suggest anthraquinones, especially alizarin, are potentially useful for controlling biofilm formation and the virulence of S. aureus. PMID:26763935

  14. Hemolytic crisis

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/003270.htm Hemolytic crisis To use the sharing features on this page, please enable JavaScript. Hemolytic crisis occurs when large numbers of red blood cells ...

  15. Complement activation induced by rabbit rheumatoid factor.

    PubMed Central

    Meyer, R R; Brown, J C

    1980-01-01

    Rabbit rheumatoid factor produced in animals by hyperimmunized with group C streptococcal vaccine activated guinea pig complement. Anti-streptococcal serum was fractionated by Sephacryl S-200 chromatography into excluded (19S) and included (7S) material and examined for hemolytic activity in a sensitive homologous hemolytic assay system. In the presence of complement, both 19S and 7S antistreptococcal serum fractions induced lysis of bovine (ox) erythrocytes coated with mildly reduced and carboxymethylated rabbit anti-erythrocyte immunoglobulin G. That rabbit rheumatoid factor was responsible for the observed hemolytic activity was substantiated by hemolytic inhibition assays. Significant inhibition of hemolysis was effected when antistreptococcal serum fractions were incubated in the presence of human immunoglobulin G, rabbit immunoglobulin G, and Fc, whereas, no inhibition was detected when the same fractions were tested in the presence of rabbit Fab or F(ab')2 fragments. Deaggregation of inhibitor preparations revealed a preferential reactivity of rheumatoid factor for rabbit immunoglobulin G. In addition to the rheumatoid factor-dependent hemolytic activity observed in humoral preparations, immunoglobulin G-specific antibody-forming cells in spleen and peripheral blood lymphocyte isolates were enumerated by plaque-forming cell assay. PMID:7399707

  16. Inhibition of the classical and lectin pathway of the complement system by recombinant LAIR-2.

    PubMed

    Olde Nordkamp, Marloes J M; Boross, Peter; Yildiz, Cafer; Jansen, J H Marco; Leusen, Jeanette H W; Wouters, Diana; Urbanus, Rolf T; Hack, C Erik; Meyaard, Linde

    2014-01-01

    Activation of complement may cause severe tissue damage in antibody-mediated allograft rejection and other antibody-mediated clinical conditions; therefore, novel potent complement inhibitors are needed. Previously, we described binding of the inhibitory receptor LAIR-1 and its soluble family member LAIR-2 to collagen. Here, we investigated binding of LAIR-1 and LAIR-2 to the complement proteins C1q and MBL, which both have collagen-like domains, and evaluated the effect of this binding on complement function. We demonstrate specific binding of recombinant LAIR proteins to both C1q and MBL. Surface plasmon resonance experiments showed that LAIR-2-Fc protein bound C1q and MBL with the highest affinity compared to LAIR-2-HIS. We, therefore, hypothesized that LAIR-2-Fc is a potent complement inhibitor. Indeed, LAIR-2-Fc inhibited C4 fixation to IgG or mannan, reduced activation of C4 by aggregated IgG in plasma and inhibited iC3b deposition on cells. Finally, LAIR-2-Fc inhibited complement-mediated lysis of cells sensitized with anti-HLA antibodies in an ex vivo model for antibody-mediated transplant rejection. Thus, LAIR-2-Fc is an effective novel complement inhibitor for the treatment and prevention of antibody-mediated allograft rejection and antibody-mediated clinical conditions. PMID:24192271

  17. Inhibition of aberrant complement activation by a dimer of acetylsalicylic acid.

    PubMed

    Lee, Moonhee; Wathier, Matthew; Love, Jennifer A; McGeer, Edith; McGeer, Patrick L

    2015-10-01

    We here report synthesis for the first time of the acetyl salicylic acid dimer 5,5'-methylenebis(2-acetoxybenzoic acid) (DAS). DAS inhibits aberrant complement activation by selectively blocking factor D of the alternative complement pathway and C9 of the membrane attack complex. We have previously identified aurin tricarboxylic and its oligomers as promising agents in this regard. DAS is much more potent, inhibiting erythrocyte hemolysis by complement-activated serum with an IC50 in the 100-170 nanomolar range. There are numerous conditions where self-damage from the complement system has been implicated in the pathology, including such chronic degenerative diseases of aging as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and age-related macular degeneration. Consequently, there is a high priority for the discovery and development of agents that can successfully treat such conditions. DAS holds considerable promise for being such an agent. PMID:26248865

  18. Hemolytic uremic syndrome

    PubMed Central

    Canpolat, Nur

    2015-01-01

    Hemolytic uremic syndrome (HUS) is a clinical syndrome characterized by the triad of thrombotic microangiopathy, thrombocytopenia, and acute kidney injury. Hemolytic uremic syndrome represents a heterogeneous group of disorders with variable etiologies that result in differences in presentation, management and outcome. In recent years, better understanding of the HUS, especially those due to genetic mutations in the alternative complement pathway have provided an update on the terminology, classification, and treatment of the disease. This review will provide the updated classification of the disease and the current diagnostic and therapeutic approaches on the complement-mediated HUS in addition to STEC-HUS which is the most common cause of the HUS in childhood. PMID:26265890

  19. Hyperglycemia inhibits complement-mediated immunological control of S. aureus in a rat model of peritonitis.

    PubMed

    Mauriello, Clifford T; Hair, Pamela S; Rohn, Reuben D; Rister, Nicholas S; Krishna, Neel K; Cunnion, Kenji M

    2014-01-01

    Hyperglycemia from diabetes is associated with increased risk of infection from S. aureus and increased severity of illness. Previous work in our laboratory demonstrated that elevated glucose (>6 mM) dramatically inhibited S. aureus-initiated complement-mediated immune effectors. Here we report in vivo studies evaluating the extent to which a hyperglycemic environment alters complement-mediated control of S. aureus infection in a rat peritonitis model. Rats were treated with streptozocin to induce diabetes or sham-treated and then inoculated i.p. with S. aureus. Rats were euthanized and had peritoneal lavage at 2 or 24 hours after infection to evaluate early and late complement-mediated effects. Hyperglycemia decreased the influx of IgG and complement components into the peritoneum in response to S. aureus infection and decreased anaphylatoxin generation. Hyperglycemia decreased C4-fragment and C3-fragment opsonization of S. aureus recovered in peritoneal fluids, compared with euglycemic or insulin-rescued rats. Hyperglycemic rats showed decreased phagocytosis efficiency compared with euglycemic rats, which correlated inversely with bacterial survival. These results suggest that hyperglycemia inhibited humoral effector recruitment, anaphylatoxin generation, and complement-mediated opsonization of S. aureus, suggesting that hyperglycemic inhibition of complement effectors may contribute to the increased risk and severity of S. aureus infections in diabetic patients. PMID:25610878

  20. Hyperglycemia Inhibits Complement-Mediated Immunological Control of S. aureus in a Rat Model of Peritonitis

    PubMed Central

    Mauriello, Clifford T.; Hair, Pamela S.; Rohn, Reuben D.; Rister, Nicholas S.; Krishna, Neel K.; Cunnion, Kenji M.

    2014-01-01

    Hyperglycemia from diabetes is associated with increased risk of infection from S. aureus and increased severity of illness. Previous work in our laboratory demonstrated that elevated glucose (>6 mM) dramatically inhibited S. aureus-initiated complement-mediated immune effectors. Here we report in vivo studies evaluating the extent to which a hyperglycemic environment alters complement-mediated control of S. aureus infection in a rat peritonitis model. Rats were treated with streptozocin to induce diabetes or sham-treated and then inoculated i.p. with S. aureus. Rats were euthanized and had peritoneal lavage at 2 or 24 hours after infection to evaluate early and late complement-mediated effects. Hyperglycemia decreased the influx of IgG and complement components into the peritoneum in response to S. aureus infection and decreased anaphylatoxin generation. Hyperglycemia decreased C4-fragment and C3-fragment opsonization of S. aureus recovered in peritoneal fluids, compared with euglycemic or insulin-rescued rats. Hyperglycemic rats showed decreased phagocytosis efficiency compared with euglycemic rats, which correlated inversely with bacterial survival. These results suggest that hyperglycemia inhibited humoral effector recruitment, anaphylatoxin generation, and complement-mediated opsonization of S. aureus, suggesting that hyperglycemic inhibition of complement effectors may contribute to the increased risk and severity of S. aureus infections in diabetic patients. PMID:25610878

  1. Distinct CD55 Isoform Synthesis and Inhibition of Complement-Dependent Cytolysis by Hepatitis C Virus.

    PubMed

    Kwon, Young-Chan; Kim, Hangeun; Meyer, Keith; Di Bisceglie, Adrian M; Ray, Ranjit

    2016-08-15

    CD55/DAF, one of the regulators of complement activation, is known to limit excess complement activation on the host cell surface by accelerating the decay of C3 convertase. We reported previously that hepatitis C virus (HCV) infection or virus core protein expression upregulates CD55 expression. CD55 associates with HCV particles, potentially protecting HCV from lysis in circulation. An increase in CD55 on the surface of HCV-infected cells may inhibit complement-mediated cell killing. In this study, we show that Abs against cancer cell surface proteins induce complement-dependent cytolysis or Ab-dependent cell-mediated cytotoxicity of immortalized human hepatocytes in the presence of CD55-blocking Ab. CD55 has a secreted isoform (sCD55) that is generated by alternative splicing. We observed that sCD55 is induced in HCV-infected or HCV replicon-harboring cells, as well as in liver biopsy samples from chronically HCV-infected patients. Conditioned medium from HCV-infected hepatoma cells (Huh7.5 cells) or immortalized human hepatocytes inhibited C3 convertase activity and complement-dependent cytolysis of sheep blood erythrocytes. Chronically HCV-infected patient sera inhibited C3 convertase activity, further implicating HCV-specific impairment of complement function in infected humans. CD55-blocking Ab inhibited erythrocyte lysis by conditioned medium, suggesting that CD55/sCD55 impairs convertase activity. Together, our data show that HCV infection induces sCD55 expression in HCV-infected cell culture-conditioned medium and inhibits C3 convertase activity. This may have implications for modulating complement-mediated immune function in the microenvironment and on HCV-harboring cells. PMID:27357152

  2. Inhibition of the classical pathway of the complement system by saliva of Amblyomma cajennense (Acari: Ixodidae).

    PubMed

    Franco, Paula F; Silva, Naylene C S; Fazito do Vale, Vladimir; Abreu, Jéssica F; Santos, Vânia C; Gontijo, Nelder F; Valenzuela, Jesus G; Pereira, Marcos H; Sant'Anna, Mauricio R V; Gomes, Alessandra P S; Araujo, Ricardo N

    2016-05-01

    Inhibition of the complement system during and after haematophagy is of utmost importance for tick success in feeding and tick development. The role of such inhibition is to minimise damage to the intestinal epithelium as well as avoiding inflammation and opsonisation of salivary molecules at the bite site. Despite its importance, the salivary anti-complement activity has been characterised only in species belonging to the Ixodes ricinus complex which saliva is able to inhibit the alternative and lectin pathways. Little is known about this activity in other species of the Ixodidae family. Thus, the aim of this study was to describe the inhibition of the classical pathway of the complement system by the saliva of Amblyomma cajennense at different stages of the haematophagy. The A. cajennense saliva and salivary gland extract (SGE) were able to inhibit the complement classical pathway through haemolytic assays with higher activity observed when saliva was used. The anti-complement activity is present in the salivary glands of starving females and also in females throughout the whole feeding process, with significant higher activity soon after tick detachment. The SGE activity from both females fed on mice or horses had no significant correlation (p > 0.05) with tick body weight. The pH found in the intestinal lumen of A. cajennense was 8.04 ± 0.08 and haemolytic assays performed at pH 8.0 showed activation of the classical pathway similarly to what occurs at pH 7.4. Consequently, inhibition could be necessary to protect the tick enterocytes. Indeed, the inhibition observed by SGE was higher in pH 8.0 in comparison to pH 7.4 reinforcing the role of saliva in protecting the intestinal cells. Further studies should be carried out in order to identify the inhibitor molecule and characterise its inhibition mechanism. PMID:26948715

  3. New insight into the effects of heparinoids on complement inhibition by C1-inhibitor.

    PubMed

    Poppelaars, F; Damman, J; de Vrij, E L; Burgerhof, J G M; Saye, J; Daha, M R; Leuvenink, H G; Uknis, M E; Seelen, M A J

    2016-06-01

    Complement activation is of major importance in numerous pathological conditions. Therefore, targeted complement inhibition is a promising therapeutic strategy. C1-esterase inhibitor (C1-INH) controls activation of the classical pathway (CP) and the lectin pathway (LP). However, conflicting data exist on inhibition of the alternative pathway (AP) by C1-INH. The inhibitory capacity of C1-INH for the CP is potentiated by heparin and other glycosaminoglycans, but no data exist for the LP and AP. The current study investigates the effects of C1-INH in the presence or absence of different clinically used heparinoids on the CP, LP and AP. Furthermore, the combined effects of heparinoids and C1-INH on coagulation were investigated. C1-INH, heparinoids or combinations were analysed in a dose-dependent fashion in the presence of pooled serum. Functional complement activities were measured simultaneously using the Wielisa(®) -kit. The activated partial thrombin time was determined using an automated coagulation analyser. The results showed that all three complement pathways were inhibited significantly by C1-INH or heparinoids. Next to their individual effects on complement activation, heparinoids also enhanced the inhibitory capacity of C1-INH significantly on the CP and LP. For the AP, significant potentiation of C1-INH by heparinoids was found; however, this was restricted to certain concentration ranges. At low concentrations the effect on blood coagulation by combining heparinoids with C1-INH was minimal. In conclusion, our study shows significant potentiating effects of heparinoids on the inhibition of all complement pathways by C1-INH. Therefore, their combined use is a promising and a potentially cost-effective treatment option for complement-mediated diseases. PMID:26874675

  4. New Compstatin Peptides Containing N-Terminal Extensions and Non-Natural Amino Acids Exhibit Potent Complement Inhibition and Improved Solubility Characteristics

    PubMed Central

    2015-01-01

    Compstatin peptides are complement inhibitors that bind and inhibit cleavage of complement C3. Peptide binding is enhanced by hydrophobic interactions; however, poor solubility promotes aggregation in aqueous environments. We have designed new compstatin peptides derived from the W4A9 sequence (Ac-ICVWQDWGAHRCT-NH2, cyclized between C2 and C12), based on structural, computational, and experimental studies. Furthermore, we developed and utilized a computational framework for the design of peptides containing non-natural amino acids. These new compstatin peptides contain polar N-terminal extensions and non-natural amino acid substitutions at positions 4 and 9. Peptides with α-modified non-natural alanine analogs at position 9, as well as peptides containing only N-terminal polar extensions, exhibited similar activity compared to W4A9, as quantified via ELISA, hemolytic, and cell-based assays, and showed improved solubility, as measured by UV absorbance and reverse-phase HPLC experiments. Because of their potency and solubility, these peptides are promising candidates for therapeutic development in numerous complement-mediated diseases. PMID:25494040

  5. Complement fixation by rheumatoid factor.

    PubMed Central

    Tanimoto, K; Cooper, N R; Johnson, J S; Vaughan, J H

    1975-01-01

    The capacity for fixation and activation of hemolytic complement by polyclonal IgM rheumatoid factors (RF) isolated from sera of patients with rheumatoid arthritis and monoclonal IgM-RF isolated from the cryoprecipitates of patients with IgM-IgG mixed cryoglobulinemia was examined. RF mixed with aggregated, reduced, and alkylated human IgG (Agg-R/A-IgG) in the fluid phase failed to significantly reduce the level of total hemolytic complement, CH50, or of individual complement components, C1, C2, C3, and C5. However, sheep erythrocytes (SRC) coated with Agg-R/A-IgG or with reduced and alkylated rabbit IgG anti-SRC antibody were hemolyzed by complement in the presence of polyclonal IgM-RF. Human and guinea pig complement worked equally well. The degree of hemolysis was in direct proportion to the hemagglutination titer of the RF against the same coated cells. Monoclonal IgM-RF, normal human IgM, and purified Waldenström macroglobulins without antiglobulin activity were all inert. Hemolysis of coated SRC by RF and complement was inhibited by prior treatment of the complement source with chelating agents, hydrazine, cobra venom factor, specific antisera to C1q, CR, C5, C6, or C8, or by heating at 56 degrees C for 30 min. Purified radiolabeled C4, C3, and C8 included in the complement source were bound to hemolysed SRC in direct proportion to the degree of hemolysis. These data indicate that polyclonal IgM-RF fix and activate complement via the classic pathway. The system described for assessing complement fixation by isolated RF is readily adaptable to use with whole human serum. PMID:1078825

  6. Monomeric C-reactive protein inhibits renal cell-directed complement activation mediated by properdin.

    PubMed

    O'Flynn, Joseph; van der Pol, Pieter; Dixon, Karen O; Prohászka, Zoltán; Daha, Mohamed R; van Kooten, Cees

    2016-06-01

    Previous studies have shown that complement activation on renal tubular cells is involved in the induction of interstitial fibrosis and cellular injury. Evidence suggests that the tubular cell damage is initiated by the alternative pathway (AP) of complement with properdin having an instrumental role. Properdin is a positive regulator of the AP, which can bind necrotic cells as well as viable proximal tubular epithelial cells (PTECs), inducing complement activation. Various studies have indicated that in the circulation there is an unidentified inhibitor of properdin. We investigated the ability of C-reactive protein (CRP), both in its monomeric (mCRP) and pentameric (pCRP) form, to inhibit AP activation and injury in vitro on renal tubular cells by fluorescent microscopy, ELISA, and flow cytometry. We demonstrated that preincubation of properdin with normal human serum inhibits properdin binding to viable PTECs. We identified mCRP as a factor able to bind to properdin in solution, thereby inhibiting its binding to PTECs. In contrast, pCRP exhibited no such binding and inhibitory effect. Furthermore, mCRP was able to inhibit properdin-directed C3 and C5b-9 deposition on viable PTECs. The inhibitory ability of mCRP was not unique for viable cells but also demonstrated for binding to necrotic Jurkat cells, a target for properdin binding and complement activation. In summary, mCRP is an inhibitor of properdin in both binding to necrotic cells and viable renal cells, regulating complement activation on the cell surface. We propose that mCRP limits amplification of tissue injury by controlling properdin-directed complement activation by damaged tissue and cells. PMID:26984957

  7. Types of Hemolytic Anemia

    MedlinePlus

    ... from the NHLBI on Twitter. Types of Hemolytic Anemia There are many types of hemolytic anemia. The ... the condition, but you develop it. Inherited Hemolytic Anemias With inherited hemolytic anemias, one or more of ...

  8. Mild hypothermia inhibits systemic and cerebral complement activation in a swine model of cardiac arrest

    PubMed Central

    Gong, Ping; Zhao, Hong; Hua, Rong; Zhang, Mingyue; Tang, Ziren; Mei, Xue; Cui, Juan; Li, Chunsheng

    2015-01-01

    Complement activation has been implicated in ischemia/reperfusion injury. This study aimed to determine whether mild hypothermia (HT) inhibits systemic and cerebral complement activation after resuscitation from cardiac arrest. Sixteen minipigs resuscitated from 8 minutes of untreated ventricular fibrillation were randomized into two groups: HT group (n=8), treated with HT (33°C) for 12 hours; and normothermia group (n=8), treated similarly as HT group except for cooling. Blood samples were collected at baseline and 0.5, 6, 12, and 24 hours after return of spontaneous circulation (ROSC). The brain cortex was harvested 24 hours after ROSC. Complement and pro-inflammatory markers were detected using enzyme-linked immunosorbent assay. Neurologic deficit scores were evaluated 24 hours after ROSC. C1q, Bb, mannose-binding lectin (MBL), C3b, C3a, C5a, interleukin-6, and tumor necrosis factor-α levels were significantly increased under normothermia within 24 hours after ROSC. However, these increases were significantly reduced by HT. Hypothermia decreased brain C1q, MBL, C3b, and C5a contents 24 hours after ROSC. Hypothermic pigs had a better neurologic outcome than normothermic pigs. In conclusion, complement is activated through classic, alternative, and MBL pathways after ROSC. Hypothermia inhibits systemic and cerebral complement activation, which may provide an additional mechanism of cerebral protection. PMID:25757755

  9. A Metalloproteinase Mirolysin of Tannerella forsythia Inhibits All Pathways of the Complement System.

    PubMed

    Jusko, Monika; Potempa, Jan; Mizgalska, Danuta; Bielecka, Ewa; Ksiazek, Miroslaw; Riesbeck, Kristian; Garred, Peter; Eick, Sigrun; Blom, Anna M

    2015-09-01

    Recent reports focusing on virulence factors of periodontal pathogens implicated proteinases as major determinants of remarkable pathogenicity of these species, with special emphasis on their capacity to modulate complement activity. In particular, bacteria-mediated cleavage of C5 and subsequent release of C5a seems to be an important phenomenon in the manipulation of the local inflammatory response in periodontitis. In this study, we present mirolysin, a novel metalloproteinase secreted by Tannerella forsythia, a well-recognized pathogen strongly associated with periodontitis. Mirolysin exhibited a strong effect on all complement pathways. It inhibited the classical and lectin complement pathways due to efficient degradation of mannose-binding lectin, ficolin-2, ficolin-3, and C4, whereas inhibition of the alternative pathway was caused by degradation of C5. This specificity toward complement largely resembled the activity of a previously characterized metalloproteinase of T. forsythia, karilysin. Interestingly, mirolysin released the biologically active C5a peptide in human plasma and induced migration of neutrophils. Importantly, we demonstrated that combination of mirolysin with karilysin, as well as a cysteine proteinase of another periodontal pathogen, Prevotella intermedia, resulted in a strong synergistic effect on complement. Furthermore, mutant strains of T. forsythia, devoid of either mirolysin or karilysin, showed diminished survival in human serum, providing further evidence for the synergistic inactivation of complement by these metalloproteinases. Taken together, our findings on interactions of mirolysin with complement significantly add to the understanding of immune evasion strategies of T. forsythia and expand the knowledge on molecular mechanisms driving pathogenic events in the infected periodontium. PMID:26209620

  10. Inhibition of the alternative complement pathway preserves photoreceptors after retinal injury

    PubMed Central

    Sweigard, J. Harry; Matsumoto, Hidetaka; Smith, Kaylee E.; Kim, Leo A.; Paschalis, Eleftherios I.; Okonuki, Yoko; Castillejos, Alexandra; Kataoka, Keiko; Hasegawa, Eiichi; Yanai, Ryoji; Husain, Deeba; Lambris, John D.; Vavvas, Demetrios; Miller, Joan W.; Connor, Kip M.

    2015-01-01

    Degeneration of photoreceptors is a primary cause of vision loss worldwide, making the underlying mechanisms surrounding photoreceptor cell death critical to developing new treatment strategies. Retinal detachment, characterized by the separation of photoreceptors from the underlying retinal pigment epithelium, is a sight-threatening event that can happen in a number of retinal diseases. The detached photoreceptors undergo apoptosis and programmed necrosis. Given that photoreceptors are nondividing cells, their loss leads to irreversible visual impairment even after successful retinal reattachment surgery. To better understand the underlying disease mechanisms, we analyzed innate immune system regulators in the vitreous of human patients with retinal detachment and correlated the results with findings in a mouse model of retinal detachment. We identified the alternative complement pathway as promoting early photoreceptor cell death during retinal detachment. Photoreceptors down-regulate membrane-bound inhibitors of complement, allowing for selective targeting by the alternative complement pathway. When photoreceptors in the detached retina were removed from the primary source of oxygen and nutrients (choroidal vascular bed), the retina became hypoxic, leading to an up-regulation of complement factor B, a key mediator of the alternative pathway. Inhibition of the alternative complement pathway in knockout mice or through pharmacological means ameliorated photoreceptor cell death during retinal detachment. Our current study begins to outline the mechanism by which the alternative complement pathway facilitates photoreceptor cell death in the damaged retina. PMID:26203084

  11. Inhibition of the alternative complement pathway preserves photoreceptors after retinal injury.

    PubMed

    Sweigard, J Harry; Matsumoto, Hidetaka; Smith, Kaylee E; Kim, Leo A; Paschalis, Eleftherios I; Okonuki, Yoko; Castillejos, Alexandra; Kataoka, Keiko; Hasegawa, Eiichi; Yanai, Ryoji; Husain, Deeba; Lambris, John D; Vavvas, Demetrios; Miller, Joan W; Connor, Kip M

    2015-07-22

    Degeneration of photoreceptors is a primary cause of vision loss worldwide, making the underlying mechanisms surrounding photoreceptor cell death critical to developing new treatment strategies. Retinal detachment, characterized by the separation of photoreceptors from the underlying retinal pigment epithelium, is a sight-threatening event that can happen in a number of retinal diseases. The detached photoreceptors undergo apoptosis and programmed necrosis. Given that photoreceptors are nondividing cells, their loss leads to irreversible visual impairment even after successful retinal reattachment surgery. To better understand the underlying disease mechanisms, we analyzed innate immune system regulators in the vitreous of human patients with retinal detachment and correlated the results with findings in a mouse model of retinal detachment. We identified the alternative complement pathway as promoting early photoreceptor cell death during retinal detachment. Photoreceptors down-regulate membrane-bound inhibitors of complement, allowing for selective targeting by the alternative complement pathway. When photoreceptors in the detached retina were removed from the primary source of oxygen and nutrients (choroidal vascular bed), the retina became hypoxic, leading to an up-regulation of complement factor B, a key mediator of the alternative pathway. Inhibition of the alternative complement pathway in knockout mice or through pharmacological means ameliorated photoreceptor cell death during retinal detachment. Our current study begins to outline the mechanism by which the alternative complement pathway facilitates photoreceptor cell death in the damaged retina. PMID:26203084

  12. The Role of Complement Inhibition in Thrombotic Angiopathies and Antiphospholipid Syndrome

    PubMed Central

    Erkan, Doruk; Salmon, Jane E.

    2016-01-01

    Antiphospholipid syndrome (APS) is characterized by thrombosis (arterial, venous, small vessel) and/or pregnancy morbidity occurring in patients with persistently positive antiphospholipid antibodies (aPL). Catastrophic APS is the most severe form of the disease, characterized by multiple organ thromboses occurring in a short period and commonly associated with thrombotic microangiopathy (TMA). Similar to patients with complement regulatory gene mutations developing TMA, increased complement activation on endothelial cells plays a role in hypercoagulability in aPL-positive patients. In mouse models of APS, activation of the complement is required and interaction of complement (C) 5a with its receptor C5aR leads to aPL-induced inflammation, placental insufficiency, and thrombosis. Anti-C5 antibody and C5aR antagonist peptides prevent aPL-mediated pregnancy loss and thrombosis in these experimental models. Clinical studies of anti-C5 monoclonal antibody in aPL-positive patients are limited to a small number of case reports. Ongoing and future clinical studies of complement inhibitors will help determine the role of complement inhibition in the management of aPL-positive patients. PMID:27020721

  13. Complement inhibition decreases early fibrogenic events in the lung of septic baboons

    PubMed Central

    Silasi-Mansat, Robert; Zhu, Hua; Georgescu, Constantin; Popescu, Narcis; Keshari, Ravi S; Peer, Glenn; Lupu, Cristina; Taylor, Fletcher B; Pereira, Heloise Anne; Kinasewitz, Gary; Lambris, John D; Lupu, Florea

    2015-01-01

    Acute respiratory distress syndrome (ARDS) induced by severe sepsis can trigger persistent inflammation and fibrosis. We have shown that experimental sepsis in baboons recapitulates ARDS progression in humans, including chronic inflammation and long-lasting fibrosis in the lung. Complement activation products may contribute to the fibroproliferative response, suggesting that complement inhibitors are potential therapeutic agents. We have been suggested that treatment of septic baboons with compstatin, a C3 convertase inhibitor protects against ARDS-induced fibroproliferation. Baboons challenged with 109 cfu/kg (LD50) live E. coli by intravenous infusion were treated or not with compstatin at the time of challenge or 5 hrs thereafter. Changes in the fibroproliferative response at 24 hrs post-challenge were analysed at both transcript and protein levels. Gene expression analysis showed that sepsis induced fibrotic responses in the lung as early as 24 hrs post-bacterial challenge. Immunochemical and biochemical analysis revealed enhanced collagen synthesis, induction of profibrotic factors and increased cell recruitment and proliferation. Specific inhibition of complement with compstatin down-regulated sepsis-induced fibrosis genes, including transforming growth factor-beta (TGF-β), connective tissue growth factor (CTGF), tissue inhibitor of metalloproteinase 1 (TIMP1), various collagens and chemokines responsible for fibrocyte recruitment (e.g. chemokine (C-C motif) ligand 2 (CCL2) and 12 (CCL12)). Compstatin decreased the accumulation of myofibroblasts and proliferating cells, reduced the production of fibrosis mediators (TGF-β, phospho-Smad-2 and CTGF) and inhibited collagen deposition. Our data demonstrate that complement inhibition effectively attenuates collagen deposition and fibrotic responses in the lung after severe sepsis. Inhibiting complement could prove an attractive strategy for preventing sepsis-induced fibrosis of the lung. PMID:26337158

  14. Potassium humate inhibits complement activation and the production of inflammatory cytokines in vitro

    SciTech Connect

    van Rensburg, C.E.J.; Naude, P.J.

    2009-08-15

    The effects of brown coal derived potassium humate on lymphocyte proliferation, cytokine production and complement activation were investigated in vitro. Potassium humate increased lymphocyte proliferation of phytohaemaglutinin A (PHA) and pokeweed mitogen (PWM) stimulated mononuclear lymphocytes (MNL) in vitro from concentrations of 20 to 80 {mu} g/ml, in a dose dependant manner. On the other hand potassium humate, at 40 {mu} g/ml, significantly inhibited the release of TNF-alpha, IL-1 beta, IL-6 and IL-10 by PHA stimulated MNL. Regarding complement activation it was found that potassium humate inhibits the activation of both the alternative and classical pathways without affecting the stability of the red blood cell membranes. These results indicate that the anti-inflammatory potential of potassium humate could be partially due to the inhibition of pro-inflammatory cytokines responsible for the initiation of these reactions as well as inhibition of complement activation. The increased lymphocyte proliferation observed, might be due to increased IL-2 production as previously been documented.

  15. [Atypical hemolytic uremic syndrome].

    PubMed

    Blasco Pelicano, Miquel; Rodríguez de Córdoba, Santiago; Campistol Plana, Josep M

    2015-11-20

    The hemolytic uremic syndrome (HUS) is a clinical entity characterized by thrombocytopenia, non-immune hemolytic anemia and renal impairment. Kidney pathology shows thrombotic microangiopathy (TMA) with endothelial cell injury leading to thrombotic occlusion of arterioles and capillaries. Traditionally, HUS was classified in 2 forms: Typical HUS, most frequently occurring in children and caused by Shiga-toxin-producing bacteria, and atypical HUS (aHUS). aHUS is associated with mutations in complement genes in 50-60% of patients and has worse prognosis, with the majority of patients developing end stage renal disease. After kidney transplantation HUS may develop as a recurrence of aHUS or as de novo disease. Over the last years, many studies have demonstrated that complement dysregulation underlies the endothelial damage that triggers the development of TMA in most of these patients. Advances in our understanding of the pathogenic mechanisms of aHUS, together with the availability of novel therapeutic options, will enable better strategies for the early diagnosis and etiological treatment, which are changing the natural history of aHUS. This review summarizes the aHUS clinical entity and describes the role of complement dysregulation in the pathogenesis of aHUS. Finally, we review the differential diagnosis and the therapeutic options available to patients with aHUS. PMID:25433773

  16. Characterization of Antibacterial and Hemolytic Activity of Synthetic Pandinin 2 Variants and Their Inhibition against Mycobacterium tuberculosis

    PubMed Central

    Rodríguez, Alexis; Villegas, Elba; Montoya-Rosales, Alejandra; Rivas-Santiago, Bruno; Corzo, Gerardo

    2014-01-01

    The contention and treatment of Mycobacterium tuberculosis and other bacteria that cause infectious diseases require the use of new type of antibiotics. Pandinin 2 (Pin2) is a scorpion venom antimicrobial peptide highly hemolytic that has a central proline residue. This residue forms a structural “kink” linked to its pore-forming activity towards human erythrocytes. In this work, the residue Pro14 of Pin2 was both substituted and flanked using glycine residues (P14G and P14GPG) based on the low hemolytic activities of antimicrobial peptides with structural motifs Gly and GlyProGly such as magainin 2 and ponericin G1, respectively. The two Pin2 variants showed antimicrobial activity against E. coli, S. aureus, and M. tuberculosis. However, Pin2 [GPG] was less hemolytic (30%) than that of Pin2 [G] variant. In addition, based on the primary structure of Pin2 [G] and Pin2 [GPG], two short peptide variants were designed and chemically synthesized keeping attention to their physicochemical properties such as hydrophobicity and propensity to adopt alpha-helical conformations. The aim to design these two short antimicrobial peptides was to avoid the drawback cost associated to the synthesis of peptides with large sequences. The short Pin2 variants named Pin2 [14] and Pin2 [17] showed antibiotic activity against E. coli and M. tuberculosis. Besides, Pin2 [14] presented only 25% of hemolysis toward human erythrocytes at concentrations as high as 100 µM, while the peptide Pin2 [17] did not show any hemolytic effect at the same concentration. Furthermore, these short antimicrobial peptides had better activity at molar concentrations against multidrug resistance M. tuberculosis than that of the conventional antibiotics ethambutol, isoniazid and rifampicin. Therefore, Pin2 [14] and Pin2 [17] have the potential to be used as an alternative antibiotics and anti-tuberculosis agents with reduced hemolytic effects. PMID:25019413

  17. Autoimmune hemolytic anemia.

    PubMed

    Dacie, J V

    1975-10-01

    Warm-type autoantibodies of autoimmune hemolytic anemia (AIHA) are usually IgG but may be IgM or IgA. They are usual Rh specific. Cold-type antibodies are IgM or IgG (Donath-Landsteiner [DL] antibody). IgM antibodies are usually anit-l (occasionally anti-i) and DL antibodies anti-P. The warm IgG antibodies do not fix complement (C); they cause red blood cell (RBC) destruction predominantly in the spleen as the result of interaction between fixing; they cause RBC destruction either by intravascular lysis (complement sequence completed) or by interaction between C3-coated RBCs and phagocytes in liver and spleen. Gentic factors, immunoglobulin deficiency, somatic mutation, viral infections and drugs, and failure of T-lymphocyte function, all probably play a part in breaking immunological tolerance and the development of AIHA. PMID:1164110

  18. Inhibition of the alternative complement pathway by antisense oligonucleotides targeting complement factor B improves lupus nephritis in mice.

    PubMed

    Grossman, Tamar R; Hettrick, Lisa A; Johnson, Robert B; Hung, Gene; Peralta, Raechel; Watt, Andrew; Henry, Scott P; Adamson, Peter; Monia, Brett P; McCaleb, Michael L

    2016-06-01

    Systemic lupus erythematosus is an autoimmune disease that manifests in widespread complement activation and deposition of complement fragments in the kidney. The complement pathway is believed to play a significant role in the pathogenesis and in the development of lupus nephritis. Complement factor B is an important activator of the alternative complement pathway and increasing evidence supports reducing factor B as a potential novel therapy to lupus nephritis. Here we investigated whether pharmacological reduction of factor B expression using antisense oligonucleotides could be an effective approach for the treatment of lupus nephritis. We identified potent and well tolerated factor B antisense oligonucleotides that resulted in significant reductions in hepatic and plasma factor B levels when administered to normal mice. To test the effects of factor B antisense oligonucleotides on lupus nephritis, we used two different mouse models, NZB/W F1 and MRL/lpr mice, that exhibit lupus nephritis like renal pathology. Antisense oligonucleotides mediated reductions in circulating factor B levels were associated with significant improvements in renal pathology, reduced glomerular C3 deposition and proteinuria, and improved survival. These data support the strategy of using factor B antisense oligonucleotides for treatment of lupus nephritis in humans. PMID:26307001

  19. An Anti-C1s Monoclonal, TNT003, Inhibits Complement Activation Induced by Antibodies Against HLA.

    PubMed

    Thomas, K A; Valenzuela, N M; Gjertson, D; Mulder, A; Fishbein, M C; Parry, G C; Panicker, S; Reed, E F

    2015-08-01

    Antibody-mediated rejection (AMR) of solid organ transplants (SOT) is characterized by damage triggered by donor-specific antibodies (DSA) binding donor Class I and II HLA (HLA-I and HLA-II) expressed on endothelial cells. While F(ab')2 portions of DSA cause cellular activation and proliferation, Fc regions activate the classical complement cascade, resulting in complement deposition and leukocyte recruitment, both hallmark features of AMR. We characterized the ability of an anti-C1s monoclonal antibody, TNT003, to inhibit HLA antibody (HLA-Ab)-induced complement activation. Complement deposition induced by HLA-Ab was evaluated using novel cell- and bead-based assays. Human aortic endothelial cells (HAEC) were cultured with HLA-Ab and human complement; production of activated complement proteins was measured by flow cytometry. Additionally, C3d deposition was measured on single antigen beads (SAB) mixed with HLA-Ab and human complement. TNT003 inhibited HLA-Ab mediated complement deposition on HAEC in a concentration-dependent manner; C3a, C4a and C5a anaphylatoxin production was also diminished by TNT003. Finally, TNT003 blocked C3d deposition induced by Class I (HLAI-Ab)- and Class II (HLAII-Ab)-specific antibodies on SAB. These data suggest TNT003 may be useful for modulating the effects of DSA, as TNT003 inhibits complement deposition and split product formation generated by HLA-I/II-Ab in vitro. PMID:25904443

  20. Current treatment of atypical hemolytic uremic syndrome

    PubMed Central

    Kaplan, Bernard S.; Ruebner, Rebecca L.; Spinale, Joann M.; Copelovitch, Lawrence

    2014-01-01

    Summary Tremendous advances have been made in understanding the pathogenesis of atypical Hemolytic Uremic Syndrome (aHUS), an extremely rare disease. Insights into the molecular biology of aHUS resulted in rapid advances in treatment with eculizumab (Soliris®, Alexion Pharmaceuticals Inc.). Historically, aHUS was associated with very high rates of mortality and morbidity. Prior therapies included plasma therapy and/or liver transplantation. Although often life saving, these were imperfect and had many complications. We review the conditions included under the rubric of aHUS: S. pneumoniae HUS (SpHUS), inborn errors of metabolism, and disorders of complement regulation, emphasizing their differences and similarities. We focus on the clinical features, diagnosis, and pathogenesis, and treatment of aHUS that results from mutations in genes encoding alternative complement regulators, SpHUS and HUS associated with inborn errors of metabolism. Mutations in complement genes, or antibodies to their protein products, result in unregulated activity of the alternate complement pathway, endothelial injury, and thrombotic microangiopathy (TMA). Eculizumab is a humanized monoclonal antibody that inhibits the production of the terminal complement components C5a and the membrane attack complex (C5b-9) by binding to complement protein C5a. This blocks the proinflammatory and cytolytic effects of terminal complement activation. Eculizumab use has been reported in many case reports, and retrospective and prospective clinical trials in aHUS. There have been few serious side effects and no reports of tachphylaxis or drug resistance. The results are very encouraging and eculizumab is now recognized as the treatment of choice for aHUS. PMID:25343125

  1. Molecular Basis for Complement Recognition and Inhibition Determined by Crystallographic Studies of the Staphylococcal Complement Inhibitor (SCIN) Bound to C3c and C3b

    SciTech Connect

    Garcia, Brandon L.; Ramyar, Kasra X.; Tzekou, Apostolia; Ricklin, Daniel; McWhorter, William J.; Lambris, John D.; Geisbrecht, Brian V.

    2010-10-22

    The human complement system plays an essential role in innate and adaptive immunity by marking and eliminating microbial intruders. Activation of complement on foreign surfaces results in proteolytic cleavage of complement component 3 (C3) into the potent opsonin C3b, which triggers a variety of immune responses and participates in a self-amplification loop mediated by a multi-protein assembly known as the C3 convertase. The human pathogen Staphylococcus aureus has evolved a sophisticated and potent complement evasion strategy, which is predicated upon an arsenal of potent inhibitory proteins. One of these, the staphylococcal complement inhibitor (SCIN), acts at the level of the C3 convertase (C3bBb) and impairs downstream complement function by trapping the convertase in a stable but inactive state. Previously, we have shown that SCIN binds C3b directly and competitively inhibits binding of human factor H and, to a lesser degree, that of factor B to C3b. Here, we report the co-crystal structures of SCIN bound to C3b and C3c at 7.5 and 3.5 {angstrom} limiting resolution, respectively, and show that SCIN binds a critical functional area on C3b. Most significantly, the SCIN binding site sterically occludes the binding sites of both factor H and factor B. Our results give insight into SCIN binding to activated derivatives of C3, explain how SCIN can recognize C3b in the absence of other complement components, and provide a structural basis for the competitive C3b-binding properties of SCIN. In the future, this may suggest templates for the design of novel complement inhibitors based upon the SCIN structure.

  2. Inhibition of the classical pathway of complement by meningococcal capsular polysaccharides

    PubMed Central

    Agarwal, Sarika; Vasudhev, Shreekant; DeOliveira, Rosane; Ram, Sanjay

    2014-01-01

    Almost all invasive Neisseria meningitidis isolates express capsular polysaccharide. Antibody (Ab) is required for complement-dependent killing of meningococci. While alternative pathway evasion has received considerable attention, little is known about classical pathway (CP) inhibition by meningococci and forms the basis of this study. We engineered capsulated and unencapsulated isogenic mutant strains of groups A, B, C, W and Y meningococci to express similar amounts of the same factor H-binding protein (fHbp; a key component of group B meningococcal vaccines) molecule. Despite similar anti-fHbp mAb binding, significantly less C4b was deposited on all five encapsulated mutants compared to their unencapsulated counterparts (P<0.01), when purified C1 and C4 were used to deposit C4b. Reduced C4b deposition was the result of capsule-mediated inhibition of C1q engagement by Ab. C4b deposition correlated linearly with C1q engagement by anti-fHbp. While B, C, W and Y capsules limited CP-mediated killing by anti-fHbp, the unencapsulated group A mutant paradoxically was more resistant than its encapsulated counterpart. Strains varied considerably in their susceptibility to anti-fHbp and complement despite similar Ab binding, which may have implications for the activity of fHbp-based vaccines. Capsule also limited C4b deposition by anti-porin A mAbs. Capsule expression decreased binding of an anti-LOS IgM mAb (~1.2 to 2-fold reduction in fluorescence). Akin to observations with IgG, capsule also decreased IgM-mediated C4b deposition when IgM binding to the mutant strain pairs was normalized. In conclusion, we show that capsular polysaccharide, a critical meningococcal virulence factor, inhibits the CP of complement. PMID:25015832

  3. Inhibition of the classical pathway of complement by meningococcal capsular polysaccharides.

    PubMed

    Agarwal, Sarika; Vasudhev, Shreekant; DeOliveira, Rosane B; Ram, Sanjay

    2014-08-15

    Almost all invasive Neisseria meningitidis isolates express capsular polysaccharide. Ab is required for complement-dependent killing of meningococci. Although alternative pathway evasion has received considerable attention, little is known about classical pathway (CP) inhibition by meningococci, which forms the basis of this study. We engineered capsulated and unencapsulated isogenic mutant strains of groups A, B, C, W, and Y meningococci to express similar amounts of the same factor H-binding protein (fHbp; a key component of group B meningococcal vaccines) molecule. Despite similar anti-fHbp mAb binding, significantly less C4b was deposited on all five encapsulated mutants compared with their unencapsulated counterparts (p < 0.01) when purified C1 and C4 were used to deposit C4b. Reduced C4b deposition was the result of capsule-mediated inhibition of C1q engagement by Ab. C4b deposition correlated linearly with C1q engagement by anti-fHbp. Whereas B, C, W, and Y capsules limited CP-mediated killing by anti-fHbp, the unencapsulated group A mutant paradoxically was more resistant than its encapsulated counterpart. Strains varied considerably in their susceptibility to anti-fHbp and complement despite similar Ab binding, which may have implications for the activity of fHbp-based vaccines. Capsule also limited C4b deposition by anti-porin A mAbs. Capsule expression decreased binding of an anti-lipooligosaccharide IgM mAb (∼ 1.2- to 2-fold reduction in fluorescence). Akin to observations with IgG, capsule also decreased IgM-mediated C4b deposition when IgM binding to the mutant strain pairs was normalized. In conclusion, we show that capsular polysaccharide, a critical meningococcal virulence factor, inhibits the CP of complement. PMID:25015832

  4. Modified bimolecular fluorescence complementation assay to study the inhibition of transcription complex formation by JAZ proteins.

    PubMed

    Qi, Tiancong; Song, Susheng; Xie, Daoxin

    2013-01-01

    The jasmonate (JA) ZIM-domain (JAZ) proteins of Arabidopsis thaliana repress JA signaling and negatively regulate the JA responses. Recently, JAZ proteins have been found to inhibit the transcriptional function of several transcription factors, among which the basic helix-loop-helix (bHLH) (GLABRA3 [GL3], ENHANCER OF GLABRA3 [EGL3], and TRANSPARENT TESTA8 [TT8]) and R2R3-MYB (GL1 and MYB75) that can interact with each other to form bHLH-MYB complexes and further control gene expression. The bimolecular fluorescence complementation (BiFC) assay is a widely used technique to study protein-protein interactions in living cells. Here we describe a modified BiFC experimental procedure to study the inhibition of the formation of the bHLH (GL3)-MYB (GL1) complex by JAZ proteins. PMID:23615997

  5. Human erythrocytes inhibit complement-mediated solubilization of immune complexes by human serum

    SciTech Connect

    Dorval, B.L.

    1987-01-01

    The aim of this study was to develop an autologus human system to evaluate the effects of human erythrocytes on solubilization of immune complex precipitates (IC) by human serum. Incubation of IC with fresh human serum or guinea pig serum resulted in solubilization of IC. When packed erythrocytes were added to human serum or guinea pig serum binding of IC to the erythrocyte occurred and IC solubilization was inhibited significantly (p <.025). Sheep erythrocytes did not bind IC or inhibit IC solubilization. To evaluate the role of human erythrocyte complement receptor (CR1) on these findings, human erythrocytes were treated with trypsin or anti-CR1 antibodies. Both treatments abrogated IC binding to human erythrocytes but did not affect the ability of the human erythrocyte to inhibit IC solubilization. Radioimmunoassay was used to measure C3, C4 and C5 activation in human serum after incubation with IC, human erythrocytes, human erythrocytes plus IC, whole blood or in whole blood plus IC.

  6. Atypical hemolytic uremic syndrome

    PubMed Central

    2011-01-01

    Hemolytic uremic syndrome (HUS) is defined by the triad of mechanical hemolytic anemia, thrombocytopenia and renal impairment. Atypical HUS (aHUS) defines non Shiga-toxin-HUS and even if some authors include secondary aHUS due to Streptococcus pneumoniae or other causes, aHUS designates a primary disease due to a disorder in complement alternative pathway regulation. Atypical HUS represents 5 -10% of HUS in children, but the majority of HUS in adults. The incidence of complement-aHUS is not known precisely. However, more than 1000 aHUS patients investigated for complement abnormalities have been reported. Onset is from the neonatal period to the adult age. Most patients present with hemolytic anemia, thrombocytopenia and renal failure and 20% have extra renal manifestations. Two to 10% die and one third progress to end-stage renal failure at first episode. Half of patients have relapses. Mutations in the genes encoding complement regulatory proteins factor H, membrane cofactor protein (MCP), factor I or thrombomodulin have been demonstrated in 20-30%, 5-15%, 4-10% and 3-5% of patients respectively, and mutations in the genes of C3 convertase proteins, C3 and factor B, in 2-10% and 1-4%. In addition, 6-10% of patients have anti-factor H antibodies. Diagnosis of aHUS relies on 1) No associated disease 2) No criteria for Shigatoxin-HUS (stool culture and PCR for Shiga-toxins; serology for anti-lipopolysaccharides antibodies) 3) No criteria for thrombotic thrombocytopenic purpura (serum ADAMTS 13 activity > 10%). Investigation of the complement system is required (C3, C4, factor H and factor I plasma concentration, MCP expression on leukocytes and anti-factor H antibodies; genetic screening to identify risk factors). The disease is familial in approximately 20% of pedigrees, with an autosomal recessive or dominant mode of transmission. As penetrance of the disease is 50%, genetic counseling is difficult. Plasmatherapy has been first line treatment until presently

  7. Borrelia burgdorferi BBK32 Inhibits the Classical Pathway by Blocking Activation of the C1 Complement Complex.

    PubMed

    Garcia, Brandon L; Zhi, Hui; Wager, Beau; Höök, Magnus; Skare, Jon T

    2016-01-01

    Pathogens that traffic in blood, lymphatics, or interstitial fluids must adopt strategies to evade innate immune defenses, notably the complement system. Through recruitment of host regulators of complement to their surface, many pathogens are able to escape complement-mediated attack. The Lyme disease spirochete, Borrelia burgdorferi, produces a number of surface proteins that bind to factor H related molecules, which function as the dominant negative regulator of the alternative pathway of complement. Relatively less is known about how B. burgdorferi evades the classical pathway of complement despite the observation that some sensu lato strains are sensitive to classical pathway activation. Here we report that the borrelial lipoprotein BBK32 potently and specifically inhibits the classical pathway by binding with high affinity to the initiating C1 complex of complement. In addition, B. burgdorferi cells that produce BBK32 on their surface bind to both C1 and C1r and a serum sensitive derivative of B. burgdorferi is protected from killing via the classical pathway in a BBK32-dependent manner. Subsequent biochemical and biophysical approaches localized the anti-complement activity of BBK32 to its globular C-terminal domain. Mechanistic studies reveal that BBK32 acts by entrapping C1 in its zymogen form by binding and inhibiting the C1 subcomponent, C1r, which serves as the initiating serine protease of the classical pathway. To our knowledge this is the first report of a spirochetal protein acting as a direct inhibitor of the classical pathway and is the only example of a biomolecule capable of specifically and noncovalently inhibiting C1/C1r. By identifying a unique mode of complement evasion this study greatly enhances our understanding of how pathogens subvert and potentially manipulate host innate immune systems. PMID:26808924

  8. Borrelia burgdorferi BBK32 Inhibits the Classical Pathway by Blocking Activation of the C1 Complement Complex

    PubMed Central

    Wager, Beau; Höök, Magnus; Skare, Jon T.

    2016-01-01

    Pathogens that traffic in blood, lymphatics, or interstitial fluids must adopt strategies to evade innate immune defenses, notably the complement system. Through recruitment of host regulators of complement to their surface, many pathogens are able to escape complement-mediated attack. The Lyme disease spirochete, Borrelia burgdorferi, produces a number of surface proteins that bind to factor H related molecules, which function as the dominant negative regulator of the alternative pathway of complement. Relatively less is known about how B. burgdorferi evades the classical pathway of complement despite the observation that some sensu lato strains are sensitive to classical pathway activation. Here we report that the borrelial lipoprotein BBK32 potently and specifically inhibits the classical pathway by binding with high affinity to the initiating C1 complex of complement. In addition, B. burgdorferi cells that produce BBK32 on their surface bind to both C1 and C1r and a serum sensitive derivative of B. burgdorferi is protected from killing via the classical pathway in a BBK32-dependent manner. Subsequent biochemical and biophysical approaches localized the anti-complement activity of BBK32 to its globular C-terminal domain. Mechanistic studies reveal that BBK32 acts by entrapping C1 in its zymogen form by binding and inhibiting the C1 subcomponent, C1r, which serves as the initiating serine protease of the classical pathway. To our knowledge this is the first report of a spirochetal protein acting as a direct inhibitor of the classical pathway and is the only example of a biomolecule capable of specifically and noncovalently inhibiting C1/C1r. By identifying a unique mode of complement evasion this study greatly enhances our understanding of how pathogens subvert and potentially manipulate host innate immune systems. PMID:26808924

  9. Anti-hemolytic, hemagglutination inhibition and bacterial membrane disruptive properties of selected herbal extracts attenuate virulence of Carbapenem Resistant Escherichia coli.

    PubMed

    Thakur, Pallavi; Chawla, Raman; Narula, Alka; Goel, Rajeev; Arora, Rajesh; Sharma, Rakesh Kumar

    2016-06-01

    Expression of a multitude of virulence factors by multi-drug resistant microbial strains, e.g., Carbapenem Resistant Escherichia coli (Family: Enterobacteriaceae; Class: Gammaproteobacteria), is responsible for resistance against beta-lactam antibiotics. Hemolysin production and induction of hemagglutination by bacterial surface receptors inflicts direct cytotoxicity by destroying host phagocytic and epithelial cells. We have previously reported that Berberis aristata, Camellia sinensis, Cyperus rotundus Holarrhena antidysenterica and Andrographis paniculata are promising herbal leads for targeting Carbapenem resistant Escherichia coli. These herbal leads were analyzed for their anti-hemolytic potential by employing spectrophotometric assay of hemoglobin liberation. Anti-hemagglutination potential of the extracts was assessed by employing qualitative assay of visible RBC aggregate formation. Camellia sinensis (PTRC-31911-A) exhibited anti-hemolytic potential of 73.97 ± 0.03%, followed by Holarrhena antidysenterica (PTRC-8111-A) i.e., 68.32 ± 0.05%, Berberis aristata (PTRC-2111-A) i.e., 60.26 ± 0.05% and Cyperus rotundus (PTRC-31811-A) i.e., 53.76 ± 0.03%. Comprehensive, visual analysis of hemagglutination inhibition revealed that only Berberis aristata (PTRC-2111-A) and Camellia sinensis (PTRC-31911-A) exhibited anti-hemagglutination activity. However, Andrographis paniculata (PTRC-11611-A) exhibited none of the inhibitory activities. Furthermore, the pair wise correlation analysis of the tested activities with quantitative phytochemical descriptors revealed that an increased content of alkaloid; flavonoids; polyphenols, and decreased content of saponins supported both the activities. Additionally, flow cytometry revealed that cell membrane structures of CRE were damaged by extracts of Berberis aristata (PTRC-2111-A) and Camellia sinensis (PTRC-31911-A) at their respective Minimum Inhibitory Concentrations, thereby confirming noteworthy antibacterial

  10. Transient complement inhibition promotes a tumor-specific immune response through the implication of natural killer cells.

    PubMed

    Janelle, Valérie; Langlois, Marie-Pierre; Tarrab, Esther; Lapierre, Pascal; Poliquin, Laurent; Lamarre, Alain

    2014-03-01

    Although the role of the complement system in cancer development has been studied, its involvement in the development of an antitumoral immune response remains poorly understood. Using cobra venom factor (CVF) to inhibit the complement cascade via C3 molecule exhaustion in immunocompetent mice bearing B16gp33 melanoma tumors, we show that transient inhibition of the complement system allowed for the development of a more robust gp33-specific antitumoral CD8(+) T-cell response. This immune response proved to be natural killer (NK) dependent, suggesting an interaction of complement proteins with this cellular subset leading to T lymphocyte activation and enhanced cytotoxic T-cell activity against tumor cells. This study demonstrates for the first time the implication of the complement system in the development of NK-mediated cytotoxic T-cell-dependent antitumoral immune responses. The complement pathway could therefore be a potent therapeutic target to improve NK-dependent antitumoral immune responses in patients with cancer. PMID:24778316

  11. BGA66 and BGA71 facilitate complement resistance of Borrelia bavariensis by inhibiting assembly of the membrane attack complex.

    PubMed

    Hammerschmidt, Claudia; Klevenhaus, Yvonne; Koenigs, Arno; Hallström, Teresia; Fingerle, Volker; Skerka, Christine; Pos, Klaas Martinus; Zipfel, Peter F; Wallich, Reinhard; Kraiczy, Peter

    2016-01-01

    Borrelia (B.) bavariensis exhibits a marked tropism for nervous tissues and frequently causes neurological manifestations in humans. The molecular mechanism by which B. bavariensis overcomes innate immunity, in particular, complement remains elusive. In contrast to other serum-resistant spirochetes, none of the B. bavariensis isolates investigated bound complement regulators of the alternative (AP) and classical pathway (CP) or proteolytically inactivated complement components. Focusing on outer surface proteins BGA66 and BGA71, we demonstrated that both molecules either inhibit AP, CP and terminal pathway (TP) activation, or block activation of the CP and TP respectively. Both molecules bind complement components C7, C8 and C9, and thereby prevent assembly of the terminal complement complex. This inhibitory activity was confirmed by the introduction of the BGA66 and BGA71 encoding genes into a serum-sensitive B. garinii strain. Transformed spirochetes producing either BGA66 or BGA71 overcome complement-mediated killing, thus indicating that both proteins independently facilitate serum resistance of B. bavariensis. The generation of C-terminally truncated proteins as well as a chimeric BGA71 protein lead to the localization of the complement-interacting binding site within the N-terminus. Collectively, our data reveal a novel immune evasion strategy of B. bavariensis that is directed against the activation of the TP. PMID:26434356

  12. Complement component 3 inhibition by an antioxidant is neuroprotective after cerebral ischemia and reperfusion in mice

    PubMed Central

    Yang, Jiwon; Ahn, Hye-na; Chang, Minsun; Narasimhan, Purnima; Chan, Pak H.; Song, Yun Seon

    2012-01-01

    Oxidative stress after stroke is associated with the inflammatory system activation in the brain. The complement cascade, especially the degradation products of complement component 3, is a key inflammatory mediator of cerebral ischemia. We have shown that proinflammatory complement component 3 is increased by oxidative stress after ischemic stroke in mice using DNA array. In this study, we investigated whether up-regulation of complement component 3 is directly related to oxidative stress after transient focal cerebral ischemia in mice and oxygen-glucose deprivation in brain cells. Persistent up-regulation of complement component 3 expression was reduced in copper/zinc-superoxide dismutase transgenic mice, and manganese-superoxide dismutase knockout mice showed highly increased complement component 3 levels after transient focal cerebral ischemia. Antioxidant N-tert-butyl-α-phenylnitrone treatment suppressed complement component 3 expression after transient focal cerebral ischemia. Accumulation of complement component 3 in neurons and microglia was decreased by N-tert-butyl-α-phenylnitrone, which reduced infarct volume and impaired neurological deficiency after cerebral ischemia and reperfusion in mice. Small interfering RNA specific for complement component 3 transfection showed a significant increase in brain cells viability after oxygen-glucose deprivation. Our study suggests that the neuroprotective effect of antioxidants through complement component 3 suppression is a new strategy for potential therapeutic approaches in stroke. PMID:23199288

  13. Complement regulation: physiology and disease relevance

    PubMed Central

    2015-01-01

    The complement system is part of the innate immune response and as such defends against invading pathogens, removes immune complexes and damaged self-cells, aids organ regeneration, confers neuroprotection, and engages with the adaptive immune response via T and B cells. Complement activation can either benefit or harm the host organism; thus, the complement system must maintain a balance between activation on foreign or modified self surfaces and inhibition on intact host cells. Complement regulators are essential for maintaining this balance and are classified as soluble regulators, such as factor H, and membrane-bound regulators. Defective complement regulators can damage the host cell and result in the accumulation of immunological debris. Moreover, defective regulators are associated with several autoimmune diseases such as atypical hemolytic uremic syndrome, dense deposit disease, age-related macular degeneration, and systemic lupus erythematosus. Therefore, understanding the molecular mechanisms by which the complement system is regulated is important for the development of novel therapies for complement-associated diseases. PMID:26300937

  14. Minor Role of Plasminogen in Complement Activation on Cell Surfaces

    PubMed Central

    Hyvärinen, Satu; Jokiranta, T. Sakari

    2015-01-01

    Atypical hemolytic uremic syndrome (aHUS) is a rare, but severe thrombotic microangiopathy. In roughly two thirds of the patients, mutations in complement genes lead to uncontrolled activation of the complement system against self cells. Recently, aHUS patients were described with deficiency of the fibrinolytic protein plasminogen. This zymogen and its protease form plasmin have both been shown to interact with complement proteins in the fluid phase. In this work we studied the potential of plasminogen to restrict complement propagation. In hemolytic assays, plasminogen inhibited complement activation, but only when it had been exogenously activated to plasmin and when it was used at disproportionately high concentrations compared to serum. Addition of only the zymogen plasminogen into serum did not hinder complement-mediated lysis of erythrocytes. Plasminogen could not restrict deposition of complement activation products on endothelial cells either, as was shown with flow cytometry. With platelets, a very weak inhibitory effect on deposition of C3 fragments was observed, but it was considered too weak to be significant for disease pathogenesis. Thus it was concluded that plasminogen is not an important regulator of complement on self cells. Instead, addition of plasminogen was shown to clearly hinder platelet aggregation in serum. This was attributed to plasmin causing disintegration of formed platelet aggregates. We propose that reduced proteolytic activity of plasmin on structures of growing thrombi, rather than on complement activation fragments, explains the association of plasminogen deficiency with aHUS. This adds to the emerging view that factors unrelated to the complement system can also be central to aHUS pathogenesis and suggests that future research on the mechanism of the disease should expand beyond complement dysregulation. PMID:26637181

  15. Complement inhibition prevents oncolytic vaccinia virus neutralization in immune humans and cynomolgus macaques.

    PubMed

    Evgin, Laura; Acuna, Sergio A; Tanese de Souza, Christiano; Marguerie, Monique; Lemay, Chantal G; Ilkow, Carolina S; Findlay, C Scott; Falls, Theresa; Parato, Kelley A; Hanwell, David; Goldstein, Alyssa; Lopez, Roberto; Lafrance, Sandra; Breitbach, Caroline J; Kirn, David; Atkins, Harold; Auer, Rebecca C; Thurman, Joshua M; Stahl, Gregory L; Lambris, John D; Bell, John C; McCart, J Andrea

    2015-06-01

    Oncolytic viruses (OVs) have shown promising clinical activity when administered by direct intratumoral injection. However, natural barriers in the blood, including antibodies and complement, are likely to limit the ability to repeatedly administer OVs by the intravenous route. We demonstrate here that for a prototype of the clinical vaccinia virus based product Pexa-Vec, the neutralizing activity of antibodies elicited by smallpox vaccination, as well as the anamnestic response in hyperimmune virus treated cancer patients, is strictly dependent on the activation of complement. In immunized rats, complement depletion stabilized vaccinia virus in the blood and led to improved delivery to tumors. Complement depletion also enhanced tumor infection when virus was directly injected into tumors in immunized animals. The feasibility and safety of using a complement inhibitor, CP40, in combination with vaccinia virus was tested in cynomolgus macaques. CP40 pretreatment elicited an average 10-fold increase in infectious titer in the blood early after the infusion and prolonged the time during which infectious virus was detectable in the blood of animals with preexisting immunity. Capitalizing on the complement dependence of antivaccinia antibody with adjunct complement inhibitors may increase the infectious dose of oncolytic vaccinia virus delivered to tumors in virus in immune hosts. PMID:25807289

  16. Cold agglutinin-mediated autoimmune hemolytic anemia.

    PubMed

    Berentsen, Sigbjørn; Randen, Ulla; Tjønnfjord, Geir E

    2015-06-01

    Cold antibody types account for about 25% of autoimmune hemolytic anemias. Primary chronic cold agglutinin disease (CAD) is characterized by a clonal lymphoproliferative disorder. Secondary cold agglutinin syndrome (CAS) complicates specific infections and malignancies. Hemolysis in CAD and CAS is mediated by the classical complement pathway and is predominantly extravascular. Not all patients require treatment. Successful CAD therapy targets the pathogenic B-cell clone. Complement modulation seems promising in both CAD and CAS. Further development and documentation are necessary before clinical use. We review options for possible complement-directed therapy. PMID:26043385

  17. Molecules Great and Small: The Complement System.

    PubMed

    Mathern, Douglas R; Heeger, Peter S

    2015-09-01

    The complement cascade, traditionally considered an effector arm of innate immunity required for host defense against pathogens, is now recognized as a crucial pathogenic mediator of various kidney diseases. Complement components produced by the liver and circulating in the plasma undergo activation through the classical and/or mannose-binding lectin pathways to mediate anti-HLA antibody-initiated kidney transplant rejection and autoantibody-initiated GN, the latter including membranous glomerulopathy, antiglomerular basement membrane disease, and lupus nephritis. Inherited and/or acquired abnormalities of complement regulators, which requisitely limit restraint on alternative pathway complement activation, contribute to the pathogenesis of the C3 nephropathies and atypical hemolytic uremic syndrome. Increasing evidence links complement produced by endothelial cells and/or tubular cells to the pathogenesis of kidney ischemia-reperfusion injury and progressive kidney fibrosis. Data emerging since the mid-2000s additionally show that immune cells, including T cells and antigen-presenting cells, produce alternative pathway complement components during cognate interactions. The subsequent local complement activation yields production of the anaphylatoxins C3a and C5a, which bind to their respective receptors (C3aR and C5aR) on both partners to augment effector T-cell proliferation and survival, while simultaneously inhibiting regulatory T-cell induction and function. This immune cell-derived complement enhances pathogenic alloreactive T-cell immunity that results in transplant rejection and likely contributes to the pathogenesis of other T cell-mediated kidney diseases. C5a/C5aR ligations on neutrophils have additionally been shown to contribute to vascular inflammation in models of ANCA-mediated renal vasculitis. New translational immunology efforts along with the development of pharmacologic agents that block human complement components and receptors now permit

  18. Tubulointerstitial injury induced in rats by a monoclonal antibody that inhibits function of a membrane inhibitor of complement.

    PubMed Central

    Nomura, A; Nishikawa, K; Yuzawa, Y; Okada, H; Okada, N; Morgan, B P; Piddlesden, S J; Nadai, M; Hasegawa, T; Matsuo, S

    1995-01-01

    The kidney widely expresses membrane-associated complement regulatory proteins (membrane inhibitors of complement). The aim of this work was to evaluate the roles of these molecules in rat kidneys in vivo. To suppress functions of rat membrane inhibitors of complement, two mAbs, 512 and 6D1, were used. 5I2 and 6D1 inhibit functions of membrane inhibitors of complement at C3 level (rat Crry/p65) and C8/9 level (rat CD59), respectively. F(ab')2 fragment of 5I2 or 6D1 was perfused in the left kidneys, and perfusate was discarded from the renal vein. After perfusion, the left kidneys were connected to systemic circulation. In rats perfused with 5I2, mouse IgG was found in glomeruli, peritubular capillaries, vascular bundles, and tubules 15 min after recirculation. Binding of C3 and C5b-9 was evident in these areas. 1 d after perfusion with 5I2, cast formation, dilatation of tubular lumen, and tubular cell degeneration were observed. At day 4 through day 7, significant mononuclear cell infiltration and proximal tubule damage were observed. These changes were completely prevented by complement depletion. Rats perfused with 6D1 showed the binding of mouse IgG in the similar areas as 5I2, but C3 or C5b-9 deposition was not observed. Rats perfused with 6D1 or vehicle only did not show any pathology in the left kidneys. These results suggest that rat Crry/p65 plays protective roles against spontaneously occurring indiscriminate attack to tubulointerstitial tissues by autologous complement and that rat Crry/p65 is one of the important factors to maintain normal integrity of the kidney in rats. Images PMID:7593622

  19. Role of complement in porphyrin-induced photosensitivity

    SciTech Connect

    Lim, H.W.; Gigli, I.

    1981-01-01

    Addition of porphyrins to sera of guinea pigs in vitro, followed by irradiation with 405 nm light, resulted in dose-dependent inhibitions of hemolytic activity of complement. With guinea pig as an animal model, we also found that systemically administered porphyrins, followed by irradiation with 405 nm light, resulted in dose-dependent inhibition of CH50 in vivo. The erythrocytes from porphyrin-treated guinea pigs showed an increased susceptibility to hemolysis induced by 405 nm irradiation in vitro. Clinical changes in these animals were limited to light-exposed areas and consisted of erythema, crusting, and delayed growth of hair. Histologically, dermal edema, dilation of blood vessels, and infiltration of mononuclear and polymorphonuclear cells were observed. Guinea pigs irradiated with ultraviolet-B developed erythema, but had no alteration of their complement profiles. It is suggested that complement products may play a specific role in the pathogenesis of the cutaneous lesions of some porphyrias.

  20. Ulex europaeus agglutinin II (UEA-II) is a novel, potent inhibitor of complement activation.

    PubMed

    Lekowski, R; Collard, C D; Reenstra, W R; Stahl, G L

    2001-02-01

    Complement is an important mediator of vascular injury following oxidative stress. We recently demonstrated that complement activation following endothelial oxidative stress is mediated by mannose-binding lectin (MBL) and activation of the lectin complement pathway. Here, we investigated whether nine plant lectins which have a binding profile similar to that of MBL competitively inhibit MBL deposition and subsequent complement activation following human umbilical vein endothelial cell (HUVEC) oxidative stress. HUVEC oxidative stress (1% O(2), 24 hr) significantly increased Ulex europaeus agglutinin II (UEA-II) binding by 72 +/- 9% compared to normoxic cells. UEA-II inhibited MBL binding to HUVEC in a concentration-dependent manner following oxidative stress. Further, MBL inhibited UEA-II binding to HUVEC in a concentration-dependent manner following oxidative stress, suggesting a common ligand. UEA-II (< or = 100 micromol/L) did not attenuate the hemolytic activity, nor did it inhibit C3a des Arg formation from alternative or classical complement pathway-specific hemolytic assays. C3 deposition (measured by ELISA) following HUVEC oxidative stress was inhibited by UEA-II in a concentration-dependent manner (IC(50) = 10 pmol/L). UEA-II inhibited C3 and MBL co-localization (confocal microscopy) in a concentration-dependent manner on HUVEC following oxidative stress (IC(50) approximately 1 pmol/L). Finally, UEA-II significantly inhibited complement-dependent neutrophil chemotaxis, but failed to inhibit fMLP-mediated chemotaxis, following endothelial oxidative stress. These data demonstrate that UEA-II is a novel, potent inhibitor of human MBL deposition and complement activation following human endothelial oxidative stress. PMID:11266613

  1. CD44 Antibody Inhibition of Macrophage Phagocytosis Targets Fcγ Receptor- and Complement Receptor 3-Dependent Mechanisms.

    PubMed

    Amash, Alaa; Wang, Lin; Wang, Yawen; Bhakta, Varsha; Fairn, Gregory D; Hou, Ming; Peng, Jun; Sheffield, William P; Lazarus, Alan H

    2016-04-15

    Targeting CD44, a major leukocyte adhesion molecule, using specific Abs has been shown beneficial in several models of autoimmune and inflammatory diseases. The mechanisms contributing to the anti-inflammatory effects of CD44 Abs, however, remain poorly understood. Phagocytosis is a key component of immune system function and can play a pivotal role in autoimmune states where CD44 Abs have shown to be effective. In this study, we show that the well-known anti-inflammatory CD44 Ab IM7 can inhibit murine macrophage phagocytosis of RBCs. We assessed three selected macrophage phagocytic receptor systems: Fcγ receptors (FcγRs), complement receptor 3 (CR3), and dectin-1. Treatment of macrophages with IM7 resulted in significant inhibition of FcγR-mediated phagocytosis of IgG-opsonized RBCs. The inhibition of FcγR-mediated phagocytosis was at an early stage in the phagocytic process involving both inhibition of the binding of the target RBC to the macrophages and postbinding events. This CD44 Ab also inhibited CR3-mediated phagocytosis of C3bi-opsonized RBCs, but it did not affect the phagocytosis of zymosan particles, known to be mediated by the C-type lectin dectin-1. Other CD44 Abs known to have less broad anti-inflammatory activity, including KM114, KM81, and KM201, did not inhibit FcγR-mediated phagocytosis of RBCs. Taken together, these findings demonstrate selective inhibition of FcγR and CR3-mediated phagocytosis by IM7 and suggest that this broadly anti-inflammatory CD44 Ab inhibits these selected macrophage phagocytic pathways. The understanding of the immune-regulatory effects of CD44 Abs is important in the development and optimization of therapeutic strategies for the potential treatment of autoimmune conditions. PMID:26944929

  2. CspA-Mediated Binding of Human Factor H Inhibits Complement Deposition and Confers Serum Resistance in Borrelia burgdorferi▿

    PubMed Central

    Kenedy, Melisha R.; Vuppala, Santosh R.; Siegel, Corinna; Kraiczy, Peter; Akins, Darrin R.

    2009-01-01

    Borrelia burgdorferi has developed efficient mechanisms for evading the innate immune response during mammalian infection and has been shown to be resistant to the complement-mediated bactericidal activity of human serum. It is well recognized that B. burgdorferi expresses multiple lipoproteins on its surface that bind the human complement inhibitors factor H and factor H-like protein 1 (FH/FHL-1). The binding of FH/FHL-1 on the surface of B. burgdorferi is thought to enhance its ability to evade serum-mediated killing during the acute phase of infection. One of the key B. burgdorferi FH/FHL-1 binding proteins identified thus far was designated CspA. While it is known that CspA binds FH/FHL-1, it is unclear how the interaction between CspA and FH/FHL-1 specifically enhances serum resistance. To better understand how CspA mediates serum resistance in B. burgdorferi, we inactivated cspA in a virulent strain of B. burgdorferi. An affinity ligand blot immunoassay and indirect immunofluorescence revealed that the CspA mutant does not efficiently bind human FH to its surface. Consistent with the lack of FH binding, the CspA mutant was also highly sensitive to killing by human serum. Additionally, the deposition of complement components C3, C6, and C5b-9 was enhanced on the surface of the CspA mutant compared to that of the wild-type strain. The combined data lead us to conclude that the CspA-mediated binding of human FH confers serum resistance by directly inhibiting complement deposition on the surface of B. burgdorferi. PMID:19451251

  3. Complement cascade and kidney transplantation: The rediscovery of an ancient enemy

    PubMed Central

    Mella, Alberto; Messina, Maria; Lavacca, Antonio; Biancone, Luigi

    2014-01-01

    The identification of complement activity in serum and immunohistochemical samples represents a core element of nephropathology. On the basis of this observation, different experimental models and molecular studies have shown the role of this cascade in glomerular disease etiology, but the absence of inhibiting drugs have limited its importance. Since 2006, the availability of target-therapies re-defined this ancient pathway, and its blockage, as the new challenging frontier in renal disease treatment. In the graft, the complement cascade is able to initiate and propagate the damage in ischemia-reperfusion injury, C3 glomerulopathy, acute and chronic rejection, atypical hemolytic uremic syndrome and, probably, in many other conditions. The importance of complement-focused research is revealed by the evidence that eculizumab, the first complement-targeting drug, is now considered a valid option in atypical hemolytic uremic syndrome treatment but it is also under investigation in all the aforementioned conditions. In this review we evaluate the importance of complement cascade in renal transplantation diseases, focusing on available treatments, and we propose a speculative identification of areas where complement inhibition may be a promising strategy. PMID:25346889

  4. Complement Blockade with a C1 Esterase Inhibitor in Paroxysmal Nocturnal Hemoglobinuria

    PubMed Central

    DeZern, Amy E.; Uknis, Marc; Yuan, Xuan; Mukhina, Galina L; Varela, Juan; Saye, JoAnne; Pu, Jeffrey; Brodsky, Robert A.

    2014-01-01

    Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, clonal, hematopoietic stem cell disorder that manifests with a complement-mediated hemolytic anemia, bone marrow failure and a propensity for thrombosis. These patients experience both intra- and extravascular hemolysis in the context of underlying complement activation. Currently eculizumab effectively blocks the intravascular hemolysis PNH. There remains an unmet clinical need for a complement inhibitor with activity early in the complement cascade to block complement at the classical and alternative pathways. C1 esterase inhibitor (C1INH) is an endogenous human plasma protein that has broad inhibitory activity in the complement pathway through inhibition of the classical pathway by binding C1r and C1s and inhibits the mannose-binding lectin-associated serine proteases in the lectin pathway. In this study, we show that commercially available plasma derived C1INH prevents lysis induced by the alternative complement pathway, of PNH erythrocytes in human serum. Importantly, C1INH was able to block the accumulation of C3 degradation products on CD55 deficient erythrocytes from PNH patient on eculizumab therapy. This could suggest a role for inhibition of earlier phases of the complement cascade than that currently inhibited by eculizumab for incomplete or non-responders to that therapy. PMID:25034232

  5. Reducing the serine availability complements the inhibition of the glutamine metabolism to block leukemia cell growth

    PubMed Central

    Polet, Florence; Corbet, Cyril; Pinto, Adan; Rubio, Laila Illan; Martherus, Ruben; Bol, Vanesa; Drozak, Xavier; Grégoire, Vincent; Riant, Olivier; Feron, Olivier

    2016-01-01

    Leukemia cells are described as a prototype of glucose-consuming cells with a high turnover rate. The role of glutamine in fueling the tricarboxylic acid cycle of leukemia cells was however recently identified confirming its status of major anaplerotic precursor in solid tumors. Here we examined whether glutamine metabolism could represent a therapeutic target in leukemia cells and whether resistance to this strategy could arise. We found that glutamine deprivation inhibited leukemia cell growth but also led to a glucose-independent adaptation maintaining cell survival. A proteomic study revealed that glutamine withdrawal induced the upregulation of phosphoglycerate dehydrogenase (PHGDH) and phosphoserine aminotransferase (PSAT), two enzymes of the serine pathway. We further documented that both exogenous and endogenous serine were critical for leukemia cell growth and contributed to cell regrowth following glutamine deprivation. Increase in oxidative stress upon inhibition of glutamine metabolism was identified as the trigger of the upregulation of PHGDH. Finally, we showed that PHGDH silencing in vitro and the use of serine-free diet in vivo inhibited leukemia cell growth, an effect further increased when glutamine metabolism was blocked. In conclusion, this study identified serine as a key pro-survival actor that needs to be handled to sensitize leukemia cells to glutamine-targeting modalities. PMID:26625201

  6. Streptococcal pyrogenic exotoxin B cleaves properdin and inhibits complement-mediated opsonophagocytosis.

    PubMed

    Tsao, Nina; Tsai, Wan-Hua; Lin, Yee-Shin; Chuang, Woei-Jer; Wang, Chiou-Huey; Kuo, Chih-Feng

    2006-01-20

    Streptococcal pyrogenic exotoxin B (SPE B), a cysteine protease, is an important virulence factor in group A streptococcal (GAS) infection. The reduction of phagocytic activity by SPE B may help prevent bacteria from being ingested. In this study, we investigated the mechanism SPE B uses to enable bacteria to resist opsonophagocytosis. Using Western blotting and an affinity column immobilized with SPE B, we found that both SPE B and C192S, an SPE B mutant lacking protease activity, bound to serum properdin, and that SPE B, but not C192S, degraded serum properdin. Further study showed that SPE B-treated, but not C192S-treated, serum blocked the alternative complement pathway. Reconstitution of properdin into SPE B-treated serum unblocked the alternative pathway. GAS opsonized with SPE B-treated serum was more resistant to neutrophil killing than GAS opsonized with C192S-treated or normal serum. These results suggest that a novel SPE B mechanism, one which degrades serum properdin, enables GAS to resist opsonophagocytosis. PMID:16329996

  7. Laboratory tests for disorders of complement and complement regulatory proteins.

    PubMed

    Shih, Angela R; Murali, Mandakolathur R

    2015-12-01

    The complement pathway is a cascade of proteases that is involved in immune surveillance and innate immunity, as well as adaptive immunity. Dysfunction of the complement cascade may be mediated by aberrations in the pathways of activation, complement regulatory proteins, or complement deficiencies, and has been linked to a number of hematologic disorders, including paroxysmal noctural hemoglobinuria (PNH), hereditary angioedema (HAE), and atypical hemolytic-uremic syndrome (aHUS). Here, current laboratory tests for disorders of the complement pathway are reviewed, and their utility and limitations in hematologic disorders and systemic diseases are discussed. Current therapeutic advances targeting the complement pathway in treatment of complement-mediated hematologic disorders are also reviewed. PMID:26437749

  8. The Complement C3a Receptor Contributes to Melanoma Tumorigenesis by Inhibiting Neutrophil and CD4+ T Cell Responses.

    PubMed

    Nabizadeh, Jamileh A; Manthey, Helga D; Steyn, Frederik J; Chen, Weiyu; Widiapradja, Alexander; Md Akhir, Fazrena N; Boyle, Glen M; Taylor, Stephen M; Woodruff, Trent M; Rolfe, Barbara E

    2016-06-01

    The complement peptide C3a is a key component of the innate immune system and a major fragment produced following complement activation. We used a murine model of melanoma (B16-F0) to identify a hitherto unknown role for C3a-C3aR signaling in promoting tumor growth. The results show that the development and growth of B16-F0 melanomas is retarded in mice lacking C3aR, whereas growth of established melanomas can be arrested by C3aR antagonism. Flow cytometric analysis showed alterations in tumor-infiltrating leukocytes in the absence of C3aR. Specifically, neutrophils and CD4(+) T lymphocyte subpopulations were increased, whereas macrophages were reduced. The central role of neutrophils was confirmed by depletion experiments that reversed the tumor inhibitory effects observed in C3aR-deficient mice and returned tumor-infiltrating CD4(+) T cells to control levels. Analysis of the tumor microenvironment showed upregulation of inflammatory genes that may contribute to the enhanced antitumor response observed in C3aR-deficient mice. C3aR deficiency/inhibition was also protective in murine models of BRAF(V600E) mutant melanoma and colon and breast cancer, suggesting a tumor-promoting role for C3aR signaling in a range of tumor types. We propose that C3aR activation alters the tumor inflammatory milieu, thereby promoting tumor growth. Therapeutic inhibition of C3aR may therefore be an effective means to trigger an antitumor response in melanoma and other cancers. PMID:27183625

  9. Amblyomma americanum tick calreticulin binds C1q but does not inhibit activation of the classical complement cascade

    PubMed Central

    Kim, Tae Kwon; Ibelli, Adriana Mércia Guaratini; Mulenga, Albert

    2014-01-01

    In this study we characterized Amblyomma americanum (Aam) tick calreticulin (CRT) homolog in tick feeding physiology. In nature, different tick species can be found feeding on the same animal host. This suggests that different tick species found feeding on the same host can modulate the same host anti-tick defense pathways to successfully feed. From this perspective it’s plausible that different tick species can utilize universally conserved proteins such as CRT to regulate and facilitate feeding. CRT is a multi-functional protein found in most taxa that is injected into the vertebrate host during tick feeding. Apart from it’s current use as a biomarker for human tick bites, role(s) of this protein in tick feeding physiology have not been elucidated. Here we show that annotated functional CRT amino acid motifs are well conserved in tick CRT. However our data show that despite high amino acid identity levels to functionally characterized CRT homologs in other organisms, AamCRT is apparently functionally different. Pichia pastoris expressed recombinant (r) AamCRT bound C1q, the first component of the classical complement system, but it did not inhibit activation of this pathway. This contrast with reports of other parasite CRT that inhibited activation of the classical complement pathway through sequestration of C1q. Furthermore rAamCRT did not bind factor Xa in contrast to reports of parasite CRT binding factor Xa, an important protease in the blood clotting system. Consistent with this observation, rAamCRT did not affect plasma clotting or platelet aggregation aggregation. We discuss our findings in the context of tick feeding physiology. PMID:25454607

  10. Does inhibiting Sur1 complement rt-PA in cerebral ischemia?

    PubMed

    Simard, J Marc; Geng, Zhihua; Silver, Frank L; Sheth, Kevin N; Kimberly, W Taylor; Stern, Barney J; Colucci, Mario; Gerzanich, Volodymyr

    2012-09-01

    Hemorrhagic transformation (HT) associated with recombinant tissue plasminogen activator (rt-PA) complicates and limits its use in stroke. Here, we provide a focused review on the involvement of matrix metalloproteinase 9 (MMP-9) in rt-PA-associated HT in cerebral ischemia, and we review emerging evidence that the selective inhibitor of the sulfonylurea receptor 1 (Sur1), glibenclamide (U.S. adopted name, glyburide), may provide protection against rt-PA-associated HT in cerebral ischemia. Glyburide inhibits activation of MMP-9, ameliorates edema formation, swelling, and symptomatic hemorrhagic transformation, and improves preclinical outcomes in several clinically relevant models of stroke, both without and with rt-PA treatment. A retrospective clinical study comparing outcomes in diabetic patients with stroke treated with rt-PA showed that those who were previously on and were maintained on a sulfonylurea fared significantly better than those whose diabetes was managed without sulfonylureas. Inhibition of Sur1 with injectable glyburide holds promise for ameliorating rt-PA-associated HT in stroke. PMID:22994227

  11. [Autoimmune hemolytic anemia in children].

    PubMed

    Becheur, M; Bouslama, B; Slama, H; Toumi, N E H

    2015-01-01

    Autoimmune hemolytic anemia is a rare condition in children which differs from the adult form. It is defined by immune-mediated destruction of red blood cells caused by autoantibodies. Characteristics of the autoantibodies are responsible for the various clinical entities. Classifications of autoimmune hemolytic anemia include warm autoimmune hemolytic anemia, cold autoimmune hemolytic anemia, and paroxysmal cold hemoglobinuria. For each classification, this review discusses the epidemiology, etiology, clinical presentation, laboratory evaluation, and treatment options. PMID:26575109

  12. Peptide inhibitors of C3 activation as a novel strategy of complement inhibition for the treatment of paroxysmal nocturnal hemoglobinuria

    PubMed Central

    Ricklin, Daniel; Huang, Yijun; Reis, Edimara S.; Chen, Hui; Ricci, Patrizia; Lin, Zhuoer; Pascariello, Caterina; Raia, Maddalena; Sica, Michela; Del Vecchio, Luigi; Pane, Fabrizio; Lupu, Florea; Notaro, Rosario; Resuello, Ranillo R. G.; DeAngelis, Robert A.; Lambris, John D.

    2014-01-01

    Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by complement-mediated intravascular hemolysis due to the lack of CD55 and CD59 on affected erythrocytes. The anti-C5 antibody eculizumab has proven clinically effective, but uncontrolled C3 activation due to CD55 absence may result in opsonization of erythrocytes, possibly leading to clinically meaningful extravascular hemolysis. We investigated the effect of the peptidic C3 inhibitor, compstatin Cp40, and its long-acting form (polyethylene glycol [PEG]-Cp40) on hemolysis and opsonization of PNH erythrocytes in an established in vitro system. Both compounds demonstrated dose-dependent inhibition of hemolysis with IC50 ∼4 µM and full inhibition at 6 µM. Protective levels of either Cp40 or PEG-Cp40 also efficiently prevented deposition of C3 fragments on PNH erythrocytes. We further explored the potential of both inhibitors for systemic administration and performed pharmacokinetic evaluation in nonhuman primates. A single intravenous injection of PEG-Cp40 resulted in a prolonged elimination half-life of >5 days but may potentially affect the plasma levels of C3. Despite faster elimination kinetics, saturating inhibitor concentration could be reached with unmodified Cp40 through repetitive subcutaneous administration. In conclusion, peptide inhibitors of C3 activation effectively prevent hemolysis and C3 opsonization of PNH erythrocytes, and are excellent, and potentially cost-effective, candidates for further clinical investigation. PMID:24497537

  13. Heme: Modulator of Plasma Systems in Hemolytic Diseases.

    PubMed

    Roumenina, Lubka T; Rayes, Julie; Lacroix-Desmazes, Sébastien; Dimitrov, Jordan D

    2016-03-01

    Hemolytic diseases such as sickle-cell disease, β-thalassemia, malaria, and autoimmune hemolytic anemia continue to present serious clinical hurdles. In these diseases, lysis of erythrocytes causes the release of hemoglobin and heme into plasma. Extracellular heme has strong proinflammatory potential and activates immune cells and endothelium, thus contributing to disease pathogenesis. Recent studies have revealed that heme can interfere with the function of plasma effector systems such as the coagulation and complement cascades, in addition to the activity of immunoglobulins. Any perturbation in such functions may have severe pathological consequences. In this review we analyze heme interactions with coagulation, complement, and immunoglobulins. Deciphering such interactions to better understand the complex pathogenesis of hemolytic diseases is pivotal. PMID:26875449

  14. Clinical significance of complement deficiencies.

    PubMed

    Pettigrew, H David; Teuber, Suzanne S; Gershwin, M Eric

    2009-09-01

    The complement system is composed of more than 30 serum and membrane-bound proteins, all of which are needed for normal function of complement in innate and adaptive immunity. Historically, deficiencies within the complement system have been suspected when young children have had recurrent and difficult-to-control infections. As our understanding of the complement system has increased, many other diseases have been attributed to deficiencies within the complement system. Generally, complement deficiencies within the classical pathway lead to increased susceptibility to encapsulated bacterial infections as well as a syndrome resembling systemic lupus erythematosus. Complement deficiencies within the mannose-binding lectin pathway generally lead to increased bacterial infections, and deficiencies within the alternative pathway usually lead to an increased frequency of Neisseria infections. However, factor H deficiency can lead to membranoproliferative glomerulonephritis and hemolytic uremic syndrome. Finally, deficiencies within the terminal complement pathway lead to an increased incidence of Neisseria infections. Two other notable complement-associated deficiencies are complement receptor 3 and 4 deficiency, which result from a deficiency of CD18, a disease known as leukocyte adhesion deficiency type 1, and CD59 deficiency, which causes paroxysmal nocturnal hemoglobinuria. Most inherited deficiencies of the complement system are autosomal recessive, but properidin deficiency is X-linked recessive, deficiency of C1 inhibitor is autosomal dominant, and mannose-binding lectin and factor I deficiencies are autosomal co-dominant. The diversity of clinical manifestations of complement deficiencies reflects the complexity of the complement system. PMID:19758139

  15. Pseudomonas aeruginosa Uses Dihydrolipoamide Dehydrogenase (Lpd) to Bind to the Human Terminal Pathway Regulators Vitronectin and Clusterin to Inhibit Terminal Pathway Complement Attack

    PubMed Central

    Hallström, Teresia; Uhde, Melanie; Singh, Birendra; Skerka, Christine; Riesbeck, Kristian; Zipfel, Peter F.

    2015-01-01

    The opportunistic human pathogen Pseudomonas aeruginosa controls host innate immune and complement attack. Here we identify Dihydrolipoamide dehydrogenase (Lpd), a 57 kDa moonlighting protein, as the first P. aeruginosa protein that binds the two human terminal pathway inhibitors vitronectin and clusterin. Both human regulators when bound to the bacterium inhibited effector function of the terminal complement, blocked C5b-9 deposition and protected the bacterium from complement damage. P. aeruginosa when challenged with complement active human serum depleted from vitronectin was severely damaged and bacterial survival was reduced by over 50%. Similarly, when in human serum clusterin was blocked by a mAb, bacterial survival was reduced by 44%. Thus, demonstrating that Pseudomonas benefits from attachment of each human regulator and controls complement attack. The Lpd binding site in vitronectin was localized to the C-terminal region, i.e. to residues 354–363. Thus, Lpd of P. aeruginosa is a surface exposed moonlighting protein that binds two human terminal pathway inhibitors, vitronectin and clusterin and each human inhibitor when attached protected the bacterial pathogen from the action of the terminal complement pathway. Our results showed insights into the important function of Lpd as a complement regulator binding protein that might play an important role in virulence of P. aeruginosa. PMID:26368530

  16. Sustained Systemic Glucocerebrosidase Inhibition Induces Brain α-Synuclein Aggregation, Microglia and Complement C1q Activation in Mice

    PubMed Central

    Rocha, Emily M.; Smith, Gaynor A.; Park, Eric; Cao, Hongmei; Graham, Anne-Renee; Brown, Eilish; McLean, Jesse R.; Hayes, Melissa A.; Beagan, Jonathan; Izen, Sarah C.; Perez-Torres, Eduardo

    2015-01-01

    Abstract Aims: Loss-of-function mutations in GBA1, which cause the autosomal recessive lysosomal storage disease, Gaucher disease (GD), are also a key genetic risk factor for the α-synucleinopathies, including Parkinson's disease (PD) and dementia with Lewy bodies. GBA1 encodes for the lysosomal hydrolase glucocerebrosidase and reductions in this enzyme result in the accumulation of the glycolipid substrates glucosylceramide and glucosylsphingosine. Deficits in autophagy and lysosomal degradation pathways likely contribute to the pathological accumulation of α-synuclein in PD. In this report we used conduritol-β-epoxide (CBE), a potent selective irreversible competitive inhibitor of glucocerebrosidase, to model reduced glucocerebrosidase activity in vivo, and tested whether sustained glucocerebrosidase inhibition in mice could induce neuropathological abnormalities including α-synucleinopathy, and neurodegeneration. Results: Our data demonstrate that daily systemic CBE treatment over 28 days caused accumulation of insoluble α-synuclein aggregates in the substantia nigra, and altered levels of proteins involved in the autophagy lysosomal system. These neuropathological changes were paralleled by widespread neuroinflammation, upregulation of complement C1q, abnormalities in synaptic, axonal transport and cytoskeletal proteins, and neurodegeneration. Innovation: A reduction in brain GCase activity has been linked to sporadic PD and normal aging, and may contribute to the susceptibility of vulnerable neurons to degeneration. This report demonstrates that systemic reduction of GCase activity using chemical inhibition, leads to neuropathological changes in the brain reminiscent of α-synucleinopathy. Conclusions: These data reveal a link between reduced glucocerebrosidase and the development of α-synucleinopathy and pathophysiological abnormalities in mice, and support the development of GCase therapeutics to reduce α-synucleinopathy in PD and related disorders

  17. A novel anticonvulsant mechanism via inhibition of complement receptor C5ar1 in murine epilepsy models.

    PubMed

    Benson, Melissa J; Thomas, Nicola K; Talwar, Sahil; Hodson, Mark P; Lynch, Joseph W; Woodruff, Trent M; Borges, Karin

    2015-04-01

    The role of complement system-mediated inflammation is of key interest in seizure and epilepsy pathophysiology, but its therapeutic potential has not yet been explored. We observed that the pro-inflammatory C5a receptor, C5ar1, is upregulated in two mouse models after status epilepticus; the pilocarpine model and the intrahippocampal kainate model. The C5ar1 antagonist, PMX53, was used to assess potential anticonvulsant actions of blocking this receptor pathway. PMX53 was found to be anticonvulsant in several acute models (6Hz and corneal kindling) and one chronic seizure model (intrahippocampal kainate model). The effects in the 6Hz model were not found in C5ar1-deficient mice, or with an inactive PMX53 analogue suggesting that the anticonvulsant effect of PMX53 is C5ar1-specific. In the pilocarpine model, inhibition or absence of C5ar1 during status epilepticus lessened seizure power and protected hippocampal neurons from degeneration as well as halved SE-associated mortality. C5ar1-deficiency during pilocarpine-induced status epilepticus also was accompanied by attenuation of TNFα upregulation by microglia, suggesting that C5ar1 activation results in TNFα release contributing to disease. Patch clamp studies showed that C5a-induced microglial K(+) outward currents were also inhibited with PMX53 providing a potential mechanism to explain acute anticonvulsant effects. In conclusion, our data indicate that C5ar1 activation plays a role in seizure initiation and severity, as well as neuronal degeneration following status epilepticus. The widespread anticonvulsant activity of PMX53 suggests that C5ar1 represents a novel target for improved anti-epileptic drug development which may be beneficial for pharmaco-resistant patients. PMID:25681535

  18. Suppression of complement regulatory protein C1 inhibitor in vascular endothelial activation by inhibiting vascular cell adhesion molecule-1 action

    SciTech Connect

    Zhang, Haimou; Qin, Gangjian; Liang, Gang; Li, Jinan; Chiu, Isaac; Barrington, Robert A.; Liu, Dongxu . E-mail: dxliu001@yahoo.com

    2007-07-13

    Increased expression of adhesion molecules by activated endothelium is a critical feature of vascular inflammation associated with the several diseases such as endotoxin shock and sepsis/septic shock. Our data demonstrated complement regulatory protein C1 inhibitor (C1INH) prevents endothelial cell injury. We hypothesized that C1INH has the ability of an anti-endothelial activation associated with suppression of expression of adhesion molecule(s). C1INH blocked leukocyte adhesion to endothelial cell monolayer in both static assay and flow conditions. In inflammatory condition, C1INH reduced vascular cell adhesion molecule (VCAM-1) expression associated with its cytoplasmic mRNA destabilization and nuclear transcription level. Studies exploring the underlying mechanism of C1INH-mediated suppression in VCAM-1 expression were related to reduction of NF-{kappa}B activation and nuclear translocation in an I{kappa}B{alpha}-dependent manner. The inhibitory effects were associated with reduction of inhibitor I{kappa}B kinase activity and stabilization of the NF-{kappa}B inhibitor I{kappa}B. These findings indicate a novel role for C1INH in inhibition of vascular endothelial activation. These observations could provide the basis for new therapeutic application of C1INH to target inflammatory processes in different pathologic situations.

  19. Novel Complement Inhibitor Limits Severity of Experimentally Myasthenia Gravis

    PubMed Central

    Soltys, Jindrich; Kusner, Linda L.; Young, Andrew; Richmonds, Chelliah; Hatala, Denise; Gong, Bendi; Shanmugavel, Vaithesh; Kaminski, Henry J.

    2011-01-01

    Objective Complement mediated injury of the neuromuscular junction is considered a primary disease mechanism in human myasthenia gravis and animal models of experimentally acquired myasthenia gravis (EAMG). We utilized active and passive models of EAMG to investigate the efficacy of a novel C5 complement inhibitor rEV576, recombinantly produced protein derived from tick saliva, in moderating disease severity. Methods Standardized disease severity assessment, serum complement hemolytic activity, serum cytotoxicity, acetylcholine receptor (AChR) antibody concentration, IgG subclassification, and C9 deposition at the neuromuscular junction were used to assess the effect of complement inhibition on EAMG induced by administration of AChR antibody or immunization with purified AChR. Results Administration of rEV576 in passive transfer EAMG limited disease severity as evidenced by 100% survival rate and a low disease severity score. In active EAMG, rats with severe and mild EAMG were protected from worsening of disease and had limited weight loss. Serum complement activity (CH50) in severe and mild EAMG was reduced to undetectable levels during treatment, and C9 deposition at the neuromuscular junction was reduced. Treatment with rEV576 resulted in reduction of toxicity of serum from severe and mild EAMG rats. Levels of total AChR IgG, and IgG2a antibodies were similar, but unexpectedly, the concentration of complement fixing IgG1 antibodies was lower in a group of rEV576-treated animals, suggesting an effect of rEV576 on cellular immunity. Interpretation Inhibition of complement significantly reduced weakness in two models of EAMG. C5 inhibition could prove to be of significant therapeutic value in human myasthenia gravis. PMID:19194881

  20. [Clinical application of blood matching with hemolytic test in vitro for transfusion treatment of crisis puerpera with acute hemolytic anemia].

    PubMed

    Yuan, Min; Tang, Cong-Hai; Gan, Wei-Wei; Wu, A-Yang; Yang, Hui-Cong; Zhang, Tian-Xin; Huang, Yan Xue; Qiu, Lu-Zhen; Chen, Hong-Pu; Lin, Feng-Li

    2014-08-01

    This study was aimed to establish the matching method of hemolytic test in vitro, and to guide the transfusion treatment for puerpera with acute hemolytic disease. The donor's erythrocytes were sensibilized by all the antibodies in plasma of patient in vitro and were added with complement, after incubation for 6.5 hours at 38 °C, the hemolysis or no hemolysis were observed. It is safe to transfuse if the hemolysis did not occur. The results showed that when the matching difficulty happened to puerpera with acute hemolytic disease, the compatible donor could be screened by hemolytic test in vitro. There were no untoward effects after transfusion of 6 U leukocyte-depleted erythrocyte suspension. The all hemoglobin, total bilirubins, indirect bilirubin, reticulocyte, D-dimex and so on were rapidly improved in patient after transfusion , showing obvious clinical efficacy of treatment. It is concluded that when the matching results can not judge accurately compatible or incompatible through the routine method of cross matching, the agglutinated and no-hemolytic erythrocytes can be screened by hemolytic test in vitro and can be transfused with good efficacy; the hemoglobin level can be promoted rapidly, and no untoward effects occur. PMID:25130835

  1. Bovine Colostrum Contains Immunoglobulin G Antibodies against Intimin, EspA, and EspB and Inhibits Hemolytic Activity Mediated by the Type Three Secretion System of Attaching and Effacing Escherichia coli▿

    PubMed Central

    Vilte, Daniel A.; Larzábal, Mariano; Cataldi, Ángel A.; Mercado, Elsa C.

    2008-01-01

    Enterohemorrhagic Escherichia coli (EHEC) is the main cause of hemolytic-uremic syndrome, an endemic disease in Argentina which had an incidence in 2005 of 13.9 cases per 100,000 children younger than 5 years old. Cattle appear to be a major reservoir of EHEC, and a serological response to EHEC antigens has been demonstrated in natural and experimental infections. In the current study, antibodies against proteins implicated in EHEC's ability to form attaching and effacing lesions, some of which are exported to the host cell via a type three secretion system (TTSS), were identified in bovine colostrum by Western blot analysis. Twenty-seven (77.0%) of the 35 samples examined contained immunoglobulin G (IgG) antibodies against the three proteins assayed in this study: EspA, EspB, and the carboxy-terminal 280 amino acids of γ-intimin, an intimin subtype associated mainly with O157:H7 and O145:H- serotypes. Every colostrum sample was able to inhibit, in a range between 45.9 and 96.7%, the TTSS-mediated hemolytic activity of attaching and effacing E. coli. The inhibitory effect was partially mediated by IgG and lactoferrin. In conclusion, we found that early colostrum from cows contains antibodies, lactoferrin, and other unidentified substances that impair TTSS function in attaching and effacing E. coli strains. Bovine colostrum might act by reducing EHEC colonization in newborn calves and could be used as a prophylactic measure to protect non-breast-fed children against EHEC infection in an area of endemicity. PMID:18562563

  2. Bovine colostrum contains immunoglobulin G antibodies against intimin, EspA, and EspB and inhibits hemolytic activity mediated by the type three secretion system of attaching and effacing Escherichia coli.

    PubMed

    Vilte, Daniel A; Larzábal, Mariano; Cataldi, Angel A; Mercado, Elsa C

    2008-08-01

    Enterohemorrhagic Escherichia coli (EHEC) is the main cause of hemolytic-uremic syndrome, an endemic disease in Argentina which had an incidence in 2005 of 13.9 cases per 100,000 children younger than 5 years old. Cattle appear to be a major reservoir of EHEC, and a serological response to EHEC antigens has been demonstrated in natural and experimental infections. In the current study, antibodies against proteins implicated in EHEC's ability to form attaching and effacing lesions, some of which are exported to the host cell via a type three secretion system (TTSS), were identified in bovine colostrum by Western blot analysis. Twenty-seven (77.0%) of the 35 samples examined contained immunoglobulin G (IgG) antibodies against the three proteins assayed in this study: EspA, EspB, and the carboxy-terminal 280 amino acids of gamma-intimin, an intimin subtype associated mainly with O157:H7 and O145:H- serotypes. Every colostrum sample was able to inhibit, in a range between 45.9 and 96.7%, the TTSS-mediated hemolytic activity of attaching and effacing E. coli. The inhibitory effect was partially mediated by IgG and lactoferrin. In conclusion, we found that early colostrum from cows contains antibodies, lactoferrin, and other unidentified substances that impair TTSS function in attaching and effacing E. coli strains. Bovine colostrum might act by reducing EHEC colonization in newborn calves and could be used as a prophylactic measure to protect non-breast-fed children against EHEC infection in an area of endemicity. PMID:18562563

  3. Sialylation of neurites inhibits complement-mediated macrophage removal in a human macrophage-neuron Co-Culture System.

    PubMed

    Linnartz-Gerlach, Bettina; Schuy, Christine; Shahraz, Anahita; Tenner, Andrea J; Neumann, Harald

    2016-01-01

    The complement system has been implicated in the removal of dysfunctional synapses and neurites during development and in disease processes in the mouse, but it is unclear how far the mouse data can be transferred to humans. Here, we co-cultured macrophages derived from human THP1 monocytes and neurons derived from human induced pluripotent stem cells, to study the role of the complement system in a human model. Components of the complement system were expressed by the human macrophages and human neuronal culture, while receptors of the complement cascade were expressed by human macrophages as shown via gene transcript analysis and flow cytometry. We mimicked pathological conditions leading to an altered glycocalyx by treatment of human neurons with sialidases. Desialylated human neurites were opsonized by the complement component C1q. Furthermore, human neurites with an intact sialic acid cap remained untouched, while desialylated human neurites were removed and ingested by human macrophages. While blockage of the complement receptor 1 (CD35) had no effect, blockage of CD11b as part of the complement receptor 3 (CR3) reversed the effect on macrophage phagocytosis of desialylated human neurites. Data demonstrate that in the human system sialylation of the neuronal glycocalyx serves as an inhibitory flag for complement binding and CR3-mediated phagocytosis by macrophages. PMID:26257016

  4. Drug-induced immune hemolytic anemia

    MedlinePlus

    Immune hemolytic anemia secondary to drugs; Anemia - immune hemolytic - secondary to drugs ... Drugs that can cause this type of hemolytic anemia include: Cephalosporins (a class of antibiotics), most common ...

  5. Sundanese Complementation

    ERIC Educational Resources Information Center

    Kurniawan, Eri

    2013-01-01

    The focus of this thesis is the description and analysis of clausal complementation in Sundanese, an Austronesian language spoken in Indonesia. The thesis examined a range of clausal complement types in Sundanese, which consists of (i) "yen/(wi)rehna" "that" complements, (ii) "pikeun" "for" complements,…

  6. Refractory IgG Warm Autoimmune Hemolytic Anemia Treated with Eculizumab: A Novel Application of Anticomplement Therapy

    PubMed Central

    Ma, Kim; Caplan, Stephen

    2016-01-01

    Warm autoimmune hemolytic anemia (wAIHA) is the most common form of AIHA, with corticosteroids in first-line treatment resulting in a 60–80% response rate. Atypical wAIHA and IgG plus complement mediated disease have a higher treatment failure rate and higher recurrence rate. We report a case of severe wAIHA secondary to Waldenström macroglobulinemia with life threatening intravascular hemolysis refractory to prednisone, rituximab, splenectomy, and plasmapheresis. A four-week treatment of eculizumab in this heavily pretreated patient resulted in a sustained increase in hemoglobin and transfusion independence, suggesting a role for complement inhibition in refractory wAIHA. PMID:27092282

  7. [Autoimmune hemolytic anemia].

    PubMed

    Karasawa, Masamitsu

    2008-03-01

    Diagnosis of autoimmune hemolytic anemia (AIHA) requires both serologic evidence of an autoantibody and hemolysis. Based on the characteristic temperature reactivity of the autoantibody to red cell membranes, AIHA is classified into warm AIHA or cold AIHA (cold agglutinin disease and paroxysmal cold hemoglobinuria). Sensitized RBCs are destructed by intravascular and/or extravascular hemolysis. On the basis of etiology, AIHA are classified as idiopathic or secondary. The common cause of secondary AIHA is lymphoproliferative disorders, autoimmune diseases, and infections. The first line therapy of patients with warm AIHA is glucocorticoids and primary treatment for cold AIHA is avoiding cold exposure. The other standard treatments include splenectomy and immunosuppressive drugs. Recently, rituximab, a monoclonal anti-CD20 antibody, has been used in refractory AIHA with excellent responses. PMID:18326320

  8. A peptide derived from the parasite receptor, complement C2 receptor inhibitor trispanning, suppresses immune complex-mediated inflammation in mice.

    PubMed

    Inal, Jameel M; Schneider, Brigitte; Armanini, Marta; Schifferli, Jürg A

    2003-04-15

    Complement C2 receptor inhibitor trispanning (CRIT) is a Schistosoma protein that binds the human complement protein, C2. We recently showed that peptides based on the ligand binding region of CRIT inhibit the classical pathway (CP) of complement activation in human serum, using hemolytic assays and so speculated that on the parasite surface CRIT has the function of evading human complement. We now show that in vitro the C2-binding 11-aa C terminus of the first extracellular domain of CRIT, a 1.3-kDa peptide termed CRIT-H17, inhibits CP activation in a species-specific manner, inhibiting mouse and rat complement but not that from guinea pig. Hitherto, the ability of CRIT to regulate complement in vivo has not been assessed. In this study we show that by inhibiting the CP, CRIT-H17 is able to reduce immune complex-mediated inflammation (dermal reversed passive Arthus reaction) in BALB/c mice. Upon intradermal injection of CRIT-H17, and similarly with recombinant soluble complement receptor type 1, there was a 41% reduction in edema and hemorrhage, a 72% reduction in neutrophil influx, and a reduced C3 deposition. Furthermore, when H17 was administered i.v. at a 1 mg/kg dose, inflammation was reduced by 31%. We propose that CRIT-H17 is a potential therapeutic agent against CP complement-mediated inflammatory tissue destruction. PMID:12682267

  9. Use of Eculizumab in Atypical Hemolytic Uremic Syndrome, Complicating Systemic Lupus Erythematosus.

    PubMed

    Bermea, Rene S; Sharma, Niharika; Cohen, Kenneth; Liarski, Vladimir M

    2016-09-01

    Atypical hemolytic uremic syndrome is characterized by the presence of thrombocytopenia, microangiopathic hemolytic anemia, and end-organ injury. In this report, we describe two patients with systemic lupus erythematosus who presented with findings compatible with atypical hemolytic uremic syndrome, complicated by acute kidney injury that was refractory to conventional therapies. Both patients exhibited a response to eculizumab, a monoclonal antibody to complement protein C5, with stabilization of their platelet count. On 1-year follow-up from their initial presentation, their hematologic disease remained in remission without recurrence. PMID:27556240

  10. Importance of Inhibition of Binding of Complement Factor H for Serum Bactericidal Antibody Responses to Meningococcal Factor H-binding Protein Vaccines

    PubMed Central

    Konar, Monica; Granoff, Dan M.; Beernink, Peter T.

    2013-01-01

    Background. Factor H (fH) binding protein (fHbp) is part of vaccines developed for prevention of meningococcal serogroup B disease. More than 610 fHbp amino acid sequence variants have been identified, which can be classified into 2 subfamilies. The extent of cross-protection within a subfamily has been difficult to assess because of strain variation in fHbp expression. Methods. Using isogenic mutant strains, we compared cross-protective serum antibody responses of mice immunized with 7 divergent fHbp variants in subfamily B, including identification numbers (ID) 1 and 55, which were chosen for vaccine development. Results and Conclusions. In the presence of the human complement downregulator fH, the ability of the anti-fHbp antibodies to deposit sufficient complement C3b on the bacterial surface to elicit bactericidal activity required inhibition of binding of fH by the anti-fHbp antibodies. With less bound fH, the bacteria became more susceptible to complement-mediated bactericidal activity. Among the different fHbp sequence variants, those more central in a phylogenic network than ID 1 or 55 elicited anti-fHbp antibodies with broader inhibition of fH binding and broader bactericidal activity. Thus, the more central variants show promise of extending protection to strains with divergent fHbp sequences that are covered poorly by fHbp variants in clinical development. PMID:23715659

  11. Complement regulator C4BP binds to Staphylococcus aureus surface proteins SdrE and Bbp inhibiting bacterial opsonization and killing☆

    PubMed Central

    Hair, Pamela S.; Foley, Caitlin K.; Krishna, Neel K.; Nyalwidhe, Julius O.; Geoghegan, Joan A.; Foster, Timothy J.; Cunnion, Kenji M.

    2013-01-01

    Staphylococcus aureus is a premier human pathogen and the most common cause of osteoarticular, wound, and implanted device infections. We recently demonstrated S. aureus efficiently binds the classical complement regulator C4b-binding protein (C4BP) inhibiting antibody-initiated complement-mediated opsonization. Here we identify S. aureus surface protein SdrE as a C4BP-binding protein. Recombinant SdrE and recombinant bone sialoprotein-binding protein (Bbp), an allelic variant of SdrE, both efficiently bound to C4BP in heat-inactivated human serum. We previously described SdrE as binding alternative pathway regulator factor H. Recombinant SdrE and Bbp efficiently bound C4BP and factor H in serum without apparent interference. Gain of function studies utilizing Lactococcus lactis clones expressing SdrE or Bbp increased serum C4BP and factor H binding, compared with empty-vector control (WT) approximately 2-fold. Correspondingly, classical pathway-mediated C3-fragment opsonization and bacterial killing by human neutrophils decreased by half for L. lactis clones expressing SdrE or Bbp compared with WT. In summary, we identify SdrE and allelic variant Bbp as S. aureus surface proteins that bind the complement regulator C4BP inhibiting classical pathway-mediated bacterial opsonization and killing. PMID:24600566

  12. Novel Compstatin Family Peptides Inhibit Complement Activation by Drusen-Like Deposits in Human Retinal Pigmented Epithelial Cell Cultures

    PubMed Central

    Gorham, Ronald D.; Forest, David L.; Tamamis, Phanourios; de Victoria, Aliana López; Kraszni, Márta; Kieslich, Chris A.; Banna, Christopher D.; Bellows-Peterson, Meghan L.; Larive, Cynthia K.; Floudas, Christodoulos A.; Archontis, Georgios; Johnson, Lincoln V.; Morikis, Dimitrios

    2013-01-01

    We have used a novel human retinal pigmented epithelial (RPE) cell-based model that mimics drusen biogenesis and the pathobiology of age-related macular degeneration to evaluate the efficacy of newly designed peptide inhibitors of the complement system. The peptides belong to the compstatin family and, compared to existing compstatin analogs, have been optimized to promote binding to their target, complement protein C3, and to enhance solubility by improving their polarity/hydrophobicity ratios. Based on analysis of molecular dynamics simulation data of peptide-C3 complexes, novel binding features were designed by introducing intermolecular salt bridge-forming arginines at the N-terminus and at position -1 of N-terminal dipeptide extensions. Our study demonstrates that the RPE cell assay has discriminatory capability for measuring the efficacy and potency of inhibitory peptides in a macular disease environment. PMID:23954241

  13. Autoimmune hemolytic anemia: classification and therapeutic approaches.

    PubMed

    Sève, Pascal; Philippe, Pierre; Dufour, Jean-François; Broussolle, Christiane; Michel, Marc

    2008-12-01

    Autoimmune hemolytic anemia (AIHA) is a relatively uncommon cause of anemia. Classifications of AIHA include warm AIHA, cold AIHA (including mainly chronic cold agglutinin disease and paroxysmal cold hemoglobinuria), mixed-type AIHA and drug-induced AIHA. AIHA may also be further subdivided on the basis of etiology. Management of AIHA is based mainly on empirical data and on small, retrospective, uncontrolled studies. The therapeutic options for treating AIHA are increasing with monoclonal antibodies and, potentially, complement inhibitory drugs. Based on data available in the literature and our experience, we propose algorithms for the treatment of warm AIHA and cold agglutinin disease in adults. Therapeutic trials are needed in order to better stratify treatment, taking into account the promising efficacy of rituximab. PMID:21082924

  14. Hemolytic activity of venom from crown-of-thorns starfish Acanthaster planci spines

    PubMed Central

    2013-01-01

    Background The crown-of-thorns starfish Acanthaster planci is a venomous species from Taiwan whose venom provokes strong hemolytic activity. To understand the hemolytic properties of A. planci venom, samples were collected from A. planci spines in the Penghu Islands, dialyzed with distilled water, and lyophilized into A. planci spine venom (ASV) powder. Results Both crude venom and ASV cause 50% hemolysis at a concentration of 20 μg/mL. The highest hemolytic activity of ASV was measured at pH 7.0-7.4; ASV-dependent hemolysis was sharply reduced when the pH was lower than 3 or greater than 8. There was almost no hemolytic activity when the Cu2+ concentration was increased to 10 mM. Furthermore, incubation at 100°C for 30 to 60 minutes sharply decreased the hemolytic activity of ASV. After treatment with the protease α-chymotrypsin, the glycoside hydrolase cellulase, and the membrane component cholesterin, the hemolytic activity of ASV was significantly inhibited. Conclusions The results of this study provide fundamental information about A. planci spine venom. The hemolytic activity was affected by pH, temperature, metal ions, EDTA, cholesterin, proteases, and glycoside hydrolases. ASV hemolysis was inhibited by Cu2+, cholesterin, α-chymotrypsin, and cellulose, factors that might prevent the hemolytic activity of venom and provide the medical treatment for sting. PMID:24063308

  15. Sulforaphane, quercetin and catechins complement each other in elimination of advanced pancreatic cancer by miR-let-7 induction and K-ras inhibition

    PubMed Central

    APPARI, MAHESH; BABU, KAMESH R.; KACZOROWSKI, ADAM; GROSS, WOLFGANG; HERR, INGRID

    2014-01-01

    Pancreatic ductal adenocarcinoma (PDA) has the worst prognosis of all malignancies, and current therapeutic options do not target cancer stem cells (CSCs), which may be the reason for the extreme aggressiveness. The dietary agents sulforaphane and quercetin enriched e.g., in broccoli, and the main and best studied green tea catechin EGCG hold promise as anti-CSC agents in PDA. We examined the efficacy of additional catechins and the combination of these bioactive agents to stem cell features and miRNA signaling. Two established and one primary PDA cell line and non-malignant pancreatic ductal cells were used. Whereas each agent strongly inhibited colony formation, the catechins ECG and CG were more effective than EGCG. A mixture of green tea catechins (GTCs) significantly inhibited viability, migration, expression of MMP-2 and -9, ALDH1 activity, colony and spheroid formation and induced apoptosis, but the combination of GTCs with sulforaphane or quercetin was superior. Following treatment with bioactive agents, the expression of miR-let7-a was specifically induced in cancer cells but not in normal cells and it was associated with K-ras inhibition. These data demonstrate that sulforaphane, quercetin and GTC complement each other in inhibition of PDA progression by induction of miR-let7-a and inhibition of K-ras. PMID:25017900

  16. Antiinflammatory effects of endotoxin. Inhibition of rabbit polymorphonuclear leukocyte responses to complement (C5)-derived peptides in vivo and in vitro.

    PubMed Central

    Rosenbaum, J. T.; Hartiala, K. T.; Webster, R. O.; Howes, E. L.; Goldstein, I. M.

    1983-01-01

    Although capable of provoking a variety of inflammatory effects, endotoxin (bacterial lipopolysaccharide) paradoxically has been reported to be antiinflammatory. The authors have found that single intravenous injections of Escherichia coli endotoxin, 24 hours before challenge, inhibit almost completely the vascular permeability changes and exudation of polymorphonuclear leukocytes induced in rabbit skin by reversed passive Arthus reactions. Whereas intravenous injections of endotoxin also caused modest inhibition of the vascular permeability changes induced in rabbit skin by the synthetic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP), exudation of polymorphonuclear leukocytes was unaffected. Polymorphonuclear leukocytes from rabbits given single injected doses of endotoxin exhibited markedly diminished chemotactic and degranulation responses to complement (C5)-derived peptides in vitro. Responses of these cells to FMLP, however, were normal. These data suggest that selective suppression of polymorphonuclear leukocyte responses to C5-derived peptides accounts, in part, for the antiinflammatory effects of endotoxin. Images Figure 1 Figure 2 PMID:6228151

  17. Complement Test

    MedlinePlus

    ... helpful? Also known as: C1; C1q; C2; C3; C4; CH50; CH100 (among others) Formal name: Complement Activity; ... whether the system is functioning normally. C3 and C4 are the most frequently measured complement proteins. Total ...

  18. [Study on hemolytic mechanism of polyphyllin II].

    PubMed

    Ning, Li-hua; Zhou, Bo; Zhang, Yao-xiang; Li, Xin-ping

    2015-09-01

    To study the hemolytic effect of polyphyllin II (PP II) mediated by anion channel protein and glucose transporter 1 (GLUT1), in order to initially reveal its hemolytic mechanism in vitro. In the experiment, the spectrophotometric method was adopted to detect the hemolysis of PP II in vitro and the effect of anion channel-related solution and blocker, glucose channel-related inhibitor and multi-target drugs dehydroepiandrosterone (DHEA) and diazepam on the hemolysis of PP II. The scanning electron microscope and transmission electron microscope were used to observe the effect of PP II on erythrocyte (RBC) morphology. The results showed that PP II -processed blood cells were severely deformed into spherocytes, acanthocyturia and vesicae. According to the results of the PP II hemolysis experiment in vitro, the anion hypertonic solution LiCl, NaHCO3, Na2SO4 and PBS significantly inhibited the hemolysis induced by PP II (P < 0.05), while blockers NPPB and DIDS remarkably promoted it (P < 0.01). Hyperosmotic sodium chloride, fructose and glucose at specific concentrations notably antagonized the hemolysis induced by PP II (P < 0.05). The glucose channel inhibitor Cytochalasin B and verapamil remarkably antagonized the hemolysis induced by PP II (P < 0.01). The hemolysis induced by PP II could also be antagonized by 1 gmol x L(1) diazepam and 100 μmol x L(-1) DHEA pretreated for 1 min (P < 0.01). In conclusion, the hemolytic mechanism of PP II in vitro may be related to the increase in intracellular osmotic pressure and rupture of erythrocytes by changing the anion channel transport activity, with GLUT1 as the major competitive interaction site. PMID:26983211

  19. Drug-induced immune hemolytic anemia

    MedlinePlus

    Immune hemolytic anemia secondary to drugs; Anemia - immune hemolytic - secondary to drugs ... In some cases, a drug can cause the immune system to mistake your own red blood cells for foreign substances. The body responds by making ...

  20. Hemolytic anemia caused by chemicals and toxins

    MedlinePlus

    Anemia - hemolytic - caused by chemicals or toxins ... Possible substances that can cause hemolytic anemia include: Anti-malaria drugs (quinine compounds) Arsenic Dapsone Intravenous water infusion (not half-normal saline or normal saline) Metals (chromium/chromates, ...

  1. Thymoma with Autoimmune Hemolytic Anemia

    PubMed Central

    Suzuki, Kensuke; Inomata, Minehiko; Shiraishi, Shiori; Hayashi, Ryuji; Tobe, Kazuyuki

    2014-01-01

    A 38-year-old Japanese male was referred to our hospital with abnormal chest X-ray results and severe Coombs-positive hemolytic anemia. He was diagnosed with a stage IV, WHO type A thymoma and was treated with oral prednisolone (1 mg/kg/day) and subsequent chemotherapy. After chemotherapy, the patient underwent surgical resection of the thymoma. Hemolysis rapidly disappeared and did not return after the discontinuation of oral corticosteroids. Corticosteroid therapy may be preferable to chemotherapy or thymoma surgical resection in the management of autoimmune hemolytic anemia with thymoma. PMID:25722666

  2. Critical appraisal of eculizumab for atypical hemolytic uremic syndrome

    PubMed Central

    Palma, Lilian M Pereira; Langman, Craig B

    2016-01-01

    The biology of atypical hemolytic uremic syndrome has been shown to involve inability to limit activation of the alternative complement pathway, with subsequent damage to systemic endothelial beds and the vasculature, resulting in the prototypic findings of a thrombotic microangiopathy. Central to this process is the formation of the terminal membrane attack complex C5b-9. Recently, application of a monoclonal antibody that specifically binds to C5, eculizumab, became available to treat patients with atypical hemolytic uremic syndrome, replacing plasma exchange or infusion as primary therapy. This review focuses on the evidence, based on published clinical trials, case series, and case reports, on the efficacy and safety of this approach. PMID:27110144

  3. Inhibition of inflammation and fibrosis by a complement C5a receptor antagonist in DOCA-salt hypertensive rats.

    PubMed

    Iyer, Abishek; Woodruff, Trent M; Wu, Mike C L; Stylianou, Con; Reid, Robert C; Fairlie, David P; Taylor, Stephen M; Brown, Lindsay

    2011-11-01

    The anaphylatoxin C5a generated by activation of the innate immunity complement system is a potent inflammatory peptide mediator through the G-protein-coupled receptor C5aR (CD88) present in immune-inflammatory cells, including monocytes, macrophages, neutrophils, T cells, and mast cells. Inflammatory cells infiltrate and initiate the development of fibrosis in the chronically hypertensive heart. In this study, we have investigated whether treatment with a selective C5aR antagonist prevents cardiovascular remodeling in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Control and DOCA-salt rats were treated with PMX53 (AcF-[OPdChaWR], 1 mg·kg·d oral gavage) for 32 days; structural and functional changes in cardiovascular system were determined. DOCA-salt hypertension increased leukocyte extravasation into ventricular tissue, increasing collagen deposition and ventricular stiffness; PMX53 treatment attenuated these changes, thereby improving cardiac function. Further, treatment with PMX53 suppressed an increased expression of C5aR in the left ventricle from DOCA-salt rats, consistent with the reduced infiltration of inflammatory cells. Vascular endothelial dysfunction in thoracic aortic rings was attenuated by PMX53 treatment, but systolic blood pressure was unchanged in DOCA-salt rats. In the heart, PMX53 treatment attenuated inflammatory cell infiltration, fibrosis, and ventricular stiffness, indicating that C5aR is critically involved in ventricular remodeling by regulating inflammatory responses in the hypertensive heart. PMID:21753735

  4. Microangiopathic Hemolytic Anemia and Thrombocytopenia in Patients With Cancer.

    PubMed

    Morton, Jordan M; George, James N

    2016-06-01

    The unexpected occurrence of thrombotic microangiopathy (TMA), characterized by microangiopathic hemolytic anemia and thrombocytopenia, in a patient with cancer requires urgent diagnosis and appropriate management. TMA is a term used to describe multiple syndromes caused by microvascular thrombosis, including thrombotic thrombocytopenic purpura (TTP), Shiga toxin-mediated hemolytic uremic syndrome, and complement-mediated TMA. In patients with cancer, systemic microvascular metastases and bone marrow involvement can cause microangiopathic hemolytic anemia and thrombocytopenia. This occurs most often in patients with known metastatic cancer, but microangiopathic hemolytic anemia and thrombocytopenia may occur unexpectedly in patients without known metastatic disease or be the presenting features of undiagnosed cancer. TMA may also be caused by commonly used chemotherapy agents, either through dose-dependent toxicity or an acute immune-mediated reaction. These causes of TMA must be distinguished from TTP, which results from a severe deficiency of ADAMTS13 and is the most common cause of TMA among adults without cancer. The importance of this distinction is to avoid inappropriate use of plasma exchange, which is associated with major complications. Plasma exchange is the essential treatment for TTP, but it has no known benefit for patients with cancer-induced or drug-induced TMA. We will describe cancer-induced and drug-induced TMA using the experience of the Oklahoma TTP-Hemolytic Uremic Syndrome Registry and data from a systematic review of all published reports of drug-induced TMA. We will illustrate the principles of evaluation and management of these disorders with patients' stories. PMID:27288467

  5. THE ROLE OF THE SKIN BIOPSY IN THE DIAGNOSIS OF ATYPICAL HEMOLYTIC UREMIC SYNDROME

    PubMed Central

    Magro, Cynthia M.; Momtahen, Shabnam; Mulvey, J. Justin; Yassin, Aminah H.; Kaplan, Robert B.; Laurence, Jeffrey C.

    2014-01-01

    Introduction Atypical hemolytic uremic syndrome (aHUS) is a prototypic thrombotic microangiopathy attributable to complement dysregulation. In the absence of complement inhibition, progressive clinical deterioration occurs. We postulated that a biopsy of normal skin could corroborate the diagnosis of aHUS via the demonstration of vascular deposits of C5b-9. Materials and methods Biopsies of normal skin from 22 patients with and without aHUS were processed for routine light microscopy as well as immunofluorescent studies. An assessment was made for vascular C5b-9 deposition immunohistochemically and by immunofluorescence. The biopsies were obtained primarily from the forearm and or deltoid. Results Patients with classic features of atypical HUS showed insidious microvascular changes including loose luminal platelet thrombi except in two patients in whom a striking thrombogenic vasculopathy was apparent in biopsied digital ulcers. Extensive microvascular deposits of the membrane attack complex (MAC)/ C5b-9 were identified excluding one patient in whom eculizumab was initiated prior to biopsy. In 5 of the 7 patients where follow-up was available, the patients exhibited an excellent treatment response to eculizumab. Patients without diagnostic clinical features of atypical HUS failed to show significant vascular deposits of complement except two patients with TTP including one in whom a Factor H mutation was identified. Conclusion In a clinical setting where aHUS is an important diagnostic consideration, extensive microvascular deposition of C5b-9 supports the diagnosis of either aHUS or a subset of TTP patients with concomitant complement dysregulation; significant vascular C5b-9 deposition predicts clinical responsiveness to eculizumab. PMID:25893747

  6. The alternative pathway of complement and the thrombotic microangiopathies.

    PubMed

    Teoh, Chia Wei; Riedl, Magdalena; Licht, Christoph

    2016-04-01

    Thrombotic microangiopathies (TMA) are disorders defined by microangiopathic hemolytic anemia, non-immune thrombocytopenia and have multi-organ involvement including the kidneys, brain, gastrointestinal, respiratory tract and skin. Emerging evidence points to the central role of complement dysregulation in leading to microvascular endothelial injury which is crucial for the development of TMAs. This key insight has led to the development of complement-targeted therapy. Eculizumab is an anti-C5 monoclonal antibody, which has revolutionized the treatment of atypical hemolytic uremic syndrome. Several other anti-complement therapeutic agents are currently in development, offering a potential armamentarium of therapies available to treat complement-mediated TMAs. The development of sensitive, reliable and easy to perform assays to monitor complement activity and therapeutic efficacy will be key to devising an individualized treatment regime with the potential of safely weaning or discontinuing treatment in the appropriate clinical setting. PMID:27160864

  7. Physicochemical signatures of nanoparticle-dependent complement activation

    NASA Astrophysics Data System (ADS)

    Thomas, Dennis G.; Chikkagoudar, Satish; Heredia-Langner, Alejandro; Tardiff, Mark F.; Xu, Zhixiang; Hourcade, Dennis E.; Pham, Christine T. N.; Lanza, Gregory M.; Weinberger, Kilian Q.; Baker, Nathan A.

    2014-01-01

    Nanoparticles are potentially powerful therapeutic tools that have the capacity to target drug payloads and imaging agents. However, some nanoparticles can activate complement, a branch of the innate immune system, and cause adverse side-effects. Recently, we employed an in vitro hemolysis assay to measure the serum complement activity of perfluorocarbon nanoparticles that differed by size, surface charge, and surface chemistry, quantifying the nanoparticle-dependent complement activity using a metric called Residual Hemolytic Activity (RHA). In the present work, we have used a decision tree learning algorithm to derive the rules for estimating nanoparticle-dependent complement response based on the data generated from the hemolytic assay studies. Our results indicate that physicochemical properties of nanoparticles, namely, size, polydispersity index, zeta potential, and mole percentage of the active surface ligand of a nanoparticle, can serve as good descriptors for prediction of nanoparticle-dependent complement activation in the decision tree modeling framework.

  8. Atypical Hemolytic-Uremic Syndrome: A Clinical Review.

    PubMed

    Nayer, Ali; Asif, Arif

    2016-01-01

    Atypical hemolytic-uremic syndrome (HUS) is a rare life-threatening disorder characterized by microangiopathic hemolytic anemia, thrombocytopenia, and ischemic injury to organs, especially the kidneys. Microvascular injury and thrombosis are the dominant histologic findings. Complement activation through the alternative pathway plays a critical role in the pathogenesis of atypical HUS. Genetic abnormalities involving complement regulatory proteins and complement components form the molecular basis for complement activation. Endothelial cell dysfunction, probably because of the effects of complement activation, is an intermediate stage in the pathophysiologic cascade. Atypical HUS has a grave prognosis. Although mortality approaches 25% during the acute phase, end-stage renal disease develops in nearly half of patients within a year. Atypical HUS has a high recurrence rate after renal transplantation, and recurrent disease often leads to graft loss. Plasma therapy in the form of plasma exchange or infusion has remained the standard treatment for atypical HUS. However, many patients do not respond to plasma therapy and some require prolonged treatment. Approved by the Food and Drug Administration in the treatment of atypical HUS, eculizumab is a humanized monoclonal antibody that blocks cleavage of complement C5 into biologically active mediators of inflammation and cytolysis. Although case reports have shown the efficacy of eculizumab, randomized clinical trials are lacking. Therapeutic strategies targeting endothelial cells have demonstrated promising results in experimental settings. Therefore, inhibitors of angiotensin-converting enzyme, HMG-CoA reductase, and xanthine oxidase as well as antioxidants, such as ascorbic acid, may have salutary effects in patients with atypical HUS. PMID:24681522

  9. [Hemolytic anemias and vitamin B12 deficieny].

    PubMed

    Dietzfelbinger, Hermann; Hubmann, Max

    2015-08-01

    Hemolytic anemias consist of corpuscular, immun-hemolytic and toxic hemolytic anemias. Within the group of corpuscular hemolytic anemias, except for the paroxysmal nocturnal hemoglobinuria (PNH), all symptoms are caused by underlying heredetiary disorders within the red blood cell membran (hereditary spherocytosis), deficiencies of red cell enzymes (G6PDH- and pyrovatkinase deficiency) or disorders in the hemoglobin molecule (thalassaemia and sickle cell disease). Immune-hemolytic anemias are acquired hemolytic anemias and hemolysis is caused by auto- or allo-antibodies which are directed against red blood cell antigens. They are classified as warm, cold, mixed type or drug-induced hemolytic anemia. Therapy consists of glucocorticoids and other immunsuppressive drugs. Pernicious anemia is the most important vitamin B12 deficiency disorder. Diagnosis relies on cobalamin deficiency and antibodies to intrinsic factor. The management should focus on a possibly life-long replacement treatment with cobalamin. PMID:26306021

  10. The novel complement inhibitor human CUB and Sushi multiple domains 1 (CSMD1) protein promotes factor I-mediated degradation of C4b and C3b and inhibits the membrane attack complex assembly.

    PubMed

    Escudero-Esparza, Astrid; Kalchishkova, Nikolina; Kurbasic, Emila; Jiang, Wen G; Blom, Anna M

    2013-12-01

    CUB and Sushi multiple domains 1 (CSMD1) is a transmembrane protein containing 15 consecutive complement control protein (CCP) domains, which are characteristic for complement inhibitors. We expressed a membrane-bound fragment of human CSMD1 composed of the 15 C-terminal CCP domains and demonstrated that it inhibits deposition of C3b by the classical pathway on the surface of Chinese hamster ovary cells by 70% at 6% serum and of C9 (component of membrane attack complex) by 90% at 1.25% serum. Furthermore, this fragment of CSMD1 served as a cofactor to factor I-mediated degradation of C3b. In all functional assays performed, well-characterized complement inhibitors were used as positive controls, whereas Coxsackie adenovirus receptor, a protein with no effect on complement, was a negative control. Moreover, attenuation of expression in human T47 breast cancer cells that express endogenous CSMD1 significantly increased C3b deposition on these cells by 45% at 8% serum compared with that for the controls. Furthermore, by expressing a soluble 17-21 CCP fragment of CSMD1, we found that CSMD1 inhibits complement by promoting factor I-mediated C4b/C3b degradation and inhibition of MAC assembly at the level of C7. Our results revealed a novel complement inhibitor for the classical and lectin pathways. PMID:23964079

  11. Complement activation by Coccidioides immitis: in vitro and clinical studies.

    PubMed Central

    Galgiani, J N; Yam, P; Petz, L D; Williams, P L; Stevens, D A

    1980-01-01

    Mycelial- or spherule-phase derivatives of Coccidioides immitis caused a decrease in vitro of total hemolytic complement in serum from a nonsensitized person. Activation involved both classic and alternative pathways as shown by deprssion of hemolytic C4 and by generation of products of activation of components C3, C4, and factor B. In addition, functional complement activity or immunoreactive levels of complement components or both were measured in 23 patients with self-limited or disseminated coccidioidomycosis. Low total hemolytic complement was found in nine, usually during the early phase of primary illness, and was transient. Hemolytic C4 was low, and the effect of inulin to decrease complement levels was blunted, suggested both classic and alternative pathways may be deficient. However, associated depression of immunoreactive levels of components assayed (C3, C4, C5, factor B, and properdin) was not consistently found. This disparity raises the possibility of enhanced in vitro inactivation analogous to activation by immune complexes. Images Fig. 2 PMID:6901703

  12. Streptococcus pneumoniae Phosphoglycerate Kinase Is a Novel Complement Inhibitor Affecting the Membrane Attack Complex Formation*

    PubMed Central

    Blom, Anna M.; Bergmann, Simone; Fulde, Marcus; Riesbeck, Kristian; Agarwal, Vaibhav

    2014-01-01

    The Gram-positive bacterium Streptococcus pneumoniae is a major human pathogen that causes infections ranging from acute otitis media to life-threatening invasive disease. Pneumococci have evolved several strategies to circumvent the host immune response, in particular the complement attack. The pneumococcal glycolytic enzyme phosphoglycerate kinase (PGK) is both secreted and bound to the bacterial surface and simultaneously binds plasminogen and its tissue plasminogen activator tPA. In the present study we demonstrate that PGK has an additional role in modulating the complement attack. PGK interacted with the membrane attack complex (MAC) components C5, C7, and C9, thereby blocking the assembly and membrane insertion of MAC resulting in significant inhibition of the hemolytic activity of human serum. Recombinant PGK interacted in a dose-dependent manner with these terminal pathway proteins, and the interactions were ionic in nature. In addition, PGK inhibited C9 polymerization both in the fluid phase and on the surface of sheep erythrocytes. Interestingly, PGK bound several MAC proteins simultaneously. Although C5 and C7 had partially overlapping binding sites on PGK, C9 did not compete with either one for PGK binding. Moreover, PGK significantly inhibited MAC deposition via both the classical and alternative pathway at the pneumococcal surface. Additionally, upon activation plasmin(ogen) bound to PGK cleaved the central complement protein C3b thereby further modifying the complement attack. In conclusion, our data demonstrate for the first time to our knowledge a novel pneumococcal inhibitor of the terminal complement cascade aiding complement evasion by this important pathogen. PMID:25281746

  13. Hemolytic activity of Borrelia burgdorferi.

    PubMed Central

    Williams, L R; Austin, F E

    1992-01-01

    Zones of beta-hemolysis occurred around colonies of Borrelia burgdorferi grown on Barbour-Stoenner-Kelly medium containing agarose and horse blood. Blood plates were inoculated with either the infective strain Sh-2-82 or noninfective strain B-31 in an overlay and incubated in a candle jar. Both strains of B. burgdorferi displayed beta-hemolysis after 1 to 2 weeks of incubation. The hemolytic activity diffused out from the borrelial colonies, eventually resulting in lysis of the entire blood plate. Hemolysis was most pronounced with horse blood and was less intense with bovine, sheep, and rabbit blood. Hemolysis was enhanced by hot-cold incubation, which is typical of phospholipase-like activities in other bacteria. Further characterization of the borrelial hemolysin by using a spectrophotometric assay revealed its presence in the supernatant fluids of stationary-phase cultures. Detection of the borrelial hemolytic activity was dependent on activation of the hemolysin by the reducing agent cysteine. This study provides the first evidence of hemolytic activity associated with B. burgdorferi. Images PMID:1639493

  14. Inhibition of the alternative pathway of nonhuman infant complement by porin B2 contributes to virulence of Neisseria meningitidis in the infant rat model.

    PubMed

    Lewis, Lisa A; Vu, David M; Granoff, Dan M; Ram, Sanjay

    2014-06-01

    Neisseria meningitidis utilizes capsular polysaccharide, lipooligosaccharide (LOS) sialic acid, factor H binding protein (fHbp), and neisserial surface protein A (NspA) to regulate the alternative pathway (AP) of complement. Using meningococcal mutants that lacked all four of the above-mentioned molecules (quadruple mutants), we recently identified a role for PorB2 in attenuating the human AP; inhibition was mediated by human fH, a key downregulatory protein of the AP. Previous studies showed that fH downregulation of the AP via fHbp or NspA is specific for human fH. Here, we report that PorB2-expressing quadruple mutants also regulate the AP of baby rabbit and infant rat complement. Blocking a human fH binding region on PorB2 of the quadruple mutant of strain 4243 with a chimeric protein that comprised human fH domains 6 and 7 fused to murine IgG Fc enhanced AP-mediated baby rabbit C3 deposition, which provided evidence for an fH-dependent mechanism of nonhuman AP regulation by PorB2. Using isogenic mutants of strain H44/76 that differed only in their PorB molecules, we confirmed a role for PorB2 in resistance to killing by infant rat serum. The PorB2-expressing strain also caused higher levels of bacteremia in infant rats than its isogenic PorB3-expressing counterpart, thus providing a molecular basis for increased survival of PorB2 isolates in this model. These studies link PorB2 expression with infection of infant rats, which could inform the choice of meningococcal strains for use in animal models, and reveals, for the first time, that PorB2-expressing strains of N. meningitidis regulate the AP of baby rabbits and rats. PMID:24686052

  15. Inhibition of the Alternative Pathway of Nonhuman Infant Complement by Porin B2 Contributes to Virulence of Neisseria meningitidis in the Infant Rat Model

    PubMed Central

    Vu, David M.; Granoff, Dan M.; Ram, Sanjay

    2014-01-01

    Neisseria meningitidis utilizes capsular polysaccharide, lipooligosaccharide (LOS) sialic acid, factor H binding protein (fHbp), and neisserial surface protein A (NspA) to regulate the alternative pathway (AP) of complement. Using meningococcal mutants that lacked all four of the above-mentioned molecules (quadruple mutants), we recently identified a role for PorB2 in attenuating the human AP; inhibition was mediated by human fH, a key downregulatory protein of the AP. Previous studies showed that fH downregulation of the AP via fHbp or NspA is specific for human fH. Here, we report that PorB2-expressing quadruple mutants also regulate the AP of baby rabbit and infant rat complement. Blocking a human fH binding region on PorB2 of the quadruple mutant of strain 4243 with a chimeric protein that comprised human fH domains 6 and 7 fused to murine IgG Fc enhanced AP-mediated baby rabbit C3 deposition, which provided evidence for an fH-dependent mechanism of nonhuman AP regulation by PorB2. Using isogenic mutants of strain H44/76 that differed only in their PorB molecules, we confirmed a role for PorB2 in resistance to killing by infant rat serum. The PorB2-expressing strain also caused higher levels of bacteremia in infant rats than its isogenic PorB3-expressing counterpart, thus providing a molecular basis for increased survival of PorB2 isolates in this model. These studies link PorB2 expression with infection of infant rats, which could inform the choice of meningococcal strains for use in animal models, and reveals, for the first time, that PorB2-expressing strains of N. meningitidis regulate the AP of baby rabbits and rats. PMID:24686052

  16. Hemolytic Uremic Syndrome: Toxins, Vessels, and Inflammation

    PubMed Central

    Cheung, Victoria; Trachtman, Howard

    2014-01-01

    Hemolytic uremic syndrome (HUS) is characterized by thrombotic microangiopathy of the glomerular microcirculation and other vascular beds. Its defining clinical phenotype is acute kidney injury (AKI), microangiopathic anemia, and thrombocytopenia. There are many etiologies of HUS including infection by Shiga toxin-producing bacterial strains, medications, viral infections, malignancy, and mutations of genes coding for proteins involved in the alternative pathway of complement. In the aggregate, although HUS is a rare disease, it is one of the most common causes of AKI in previously healthy children and accounts for a sizable number of pediatric and adult patients who progress to end stage kidney disease. There has been great progress over the past 20 years in understanding the pathophysiology of HUS and its related disorders. There has been intense focus on vascular injury in HUS as the major mechanism of disease and target for effective therapies for this acute illness. In all forms of HUS, there is evidence of both systemic and intra-glomerular inflammation and perturbations in the immune system. Renewed investigation into these aspects of HUS may prove helpful in developing new interventions that can attenuate glomerular and tubular injury and improve clinical outcomes in patients with HUS. PMID:25593915

  17. Hemolytic uremic syndrome: toxins, vessels, and inflammation.

    PubMed

    Cheung, Victoria; Trachtman, Howard

    2014-01-01

    Hemolytic uremic syndrome (HUS) is characterized by thrombotic microangiopathy of the glomerular microcirculation and other vascular beds. Its defining clinical phenotype is acute kidney injury (AKI), microangiopathic anemia, and thrombocytopenia. There are many etiologies of HUS including infection by Shiga toxin-producing bacterial strains, medications, viral infections, malignancy, and mutations of genes coding for proteins involved in the alternative pathway of complement. In the aggregate, although HUS is a rare disease, it is one of the most common causes of AKI in previously healthy children and accounts for a sizable number of pediatric and adult patients who progress to end stage kidney disease. There has been great progress over the past 20 years in understanding the pathophysiology of HUS and its related disorders. There has been intense focus on vascular injury in HUS as the major mechanism of disease and target for effective therapies for this acute illness. In all forms of HUS, there is evidence of both systemic and intra-glomerular inflammation and perturbations in the immune system. Renewed investigation into these aspects of HUS may prove helpful in developing new interventions that can attenuate glomerular and tubular injury and improve clinical outcomes in patients with HUS. PMID:25593915

  18. Fatal carboplatin-induced immune hemolytic anemia in a child with a brain tumor

    PubMed Central

    Haley, Kristina M; Russell, Thomas B; Boshkov, Lynn; Leger, Regina M; Garratty, George; Recht, Michael; Nazemi, Kellie J

    2014-01-01

    Drug-induced immune hemolytic anemia (DIIHA) is an uncommon side effect of pharmacologic intervention. A rare mediator of DIIHA, carboplatin is an agent used to treat many pediatric cancers. We describe here, the first case of fatal carboplatin induced DIIHA in a pediatric patient and a brief review of the literature. Our patient developed acute onset of multi-organ failure with evidence of complement activation, secondary to a drug induced red cell antibody. Early recognition of the systemic insult associated with carboplatin induced hemolytic anemia may allow for future affected patients to receive plasmapheresis, a potentially effective therapy. PMID:24868179

  19. A Case of Microangiopathic Hemolytic Anemia after Myxoma Excision and Mitral Valve Repair Presenting as Hemolytic Uremic Syndrome

    PubMed Central

    Park, Young Joo; Kim, Sang Pil; Shin, Ho-Jin

    2016-01-01

    Microangiopathic hemolytic anemia occurs in a diverse group of disorders, including thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, and prosthetic cardiac valves. Hemolytic anemia also occurs as a rare complication after mitral valve repair. In this report, we describe a case of microangiopathic hemolytic anemia following myxoma excision and mitral valve repair, which was presented as hemolytic uremic syndrome. PMID:27081450

  20. A Case of Microangiopathic Hemolytic Anemia after Myxoma Excision and Mitral Valve Repair Presenting as Hemolytic Uremic Syndrome.

    PubMed

    Park, Young Joo; Kim, Sang Pil; Shin, Ho-Jin; Choi, Jung Hyun

    2016-03-01

    Microangiopathic hemolytic anemia occurs in a diverse group of disorders, including thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, and prosthetic cardiac valves. Hemolytic anemia also occurs as a rare complication after mitral valve repair. In this report, we describe a case of microangiopathic hemolytic anemia following myxoma excision and mitral valve repair, which was presented as hemolytic uremic syndrome. PMID:27081450

  1. Entamoeba histolytica and E. dispar Calreticulin: Inhibition of Classical Complement Pathway and Differences in the Level of Expression in Amoebic Liver Abscess

    PubMed Central

    Ximénez, Cecilia; González, Enrique; Nieves, Miriam E.; Silva-Olivares, Angélica; Shibayama, Mineko; Galindo-Gómez, Silvia; Escobar-Herrera, Jaime; García de León, Ma del Carmen; Morán, Patricia; Valadez, Alicia; Rojas, Liliana; Hernández, Eric G.; Partida, Oswaldo; Cerritos, René

    2014-01-01

    The role of calreticulin (CRT) in host-parasite interactions has recently become an important area of research. Information about the functions of calreticulin and its relevance to the physiology of Entamoeba parasites is limited. The present work demonstrates that CRT of both pathogenic E. histolytica and nonpathogenic E. dispar species specifically interacted with human C1q inhibiting the activation of the classical complement pathway. Using recombinant EhCRT protein, we demonstrate that CRT interaction site and human C1q is located at the N-terminal region of EhCRT. The immunofluorescence and confocal microscopy experiments show that CRT and human C1q colocalize in the cytoplasmic vesicles and near to the surface membrane of previously permeabilized trophozoites or are incubated with normal human serum which is known to destroy trophozoites. In the presence of peripheral mononuclear blood cells, the distribution of EhCRT and C1q is clearly over the surface membrane of trophozoites. Nevertheless, the level of expression of CRT in situ in lesions of amoebic liver abscess (ALA) in the hamster model is different in both Entamoeba species; this molecule is expressed in higher levels in E. histolytica than in E. dispar. This result suggests that EhCRT may modulate some functions during the early moments of the host-parasite relationship. PMID:24860808

  2. Partial ADAMTS13 deficiency in atypical hemolytic uremic syndrome

    PubMed Central

    Feng, Shuju; Eyler, Stephen J.; Zhang, Yuzhou; Maga, Tara; Nester, Carla M.; Kroll, Michael H.

    2013-01-01

    Complement dysregulation leads to atypical hemolytic uremic syndrome (aHUS), while ADAMTS13 deficiency causes thrombotic thrombocytopenic purpura. We investigated whether genetic variations in the ADAMTS13 gene partially explain the reduced activity known to occur in some patients with aHUS. We measured complement activity and ADAMTS13 function, and completed mutation screening of multiple complement genes and ADAMTS13 in a large cohort of aHUS patients. In over 50% of patients we identified complement gene mutations. Surprisingly, 80% of patients also carried at least 1 nonsynonymous change in ADAMTS13, and in 38% of patients, multiple ADAMTS13 variations were found. Six of the 9 amino acid substitutions in ADAMTS13 were common single nucleotide polymorphisms; however, 3 variants—A747V, V832M, and R1096H— were rare, with minor allele frequencies of 0.0094%, 0.5%, and 0.32%, respectively. Reduced complement and ADAMTS13 activity (<60% of normal activity) were found in over 60% and 50% of patients, respectively. We concluded that partial ADAMTS13 deficiency is a common finding in aHUS patients and that genetic screening and functional tests of ADAMTS13 should be considered in these patients. PMID:23847193

  3. Peptide inhibitor of complement c1, a novel suppressor of classical pathway activation: mechanistic studies and clinical potential.

    PubMed

    Sharp, Julia A; Whitley, Pamela H; Cunnion, Kenji M; Krishna, Neel K

    2014-01-01

    The classical pathway of complement plays multiple physiological roles including modulating immunological effectors initiated by adaptive immune responses and an essential homeostatic role in the clearance of damaged self-antigens. However, dysregulated classical pathway activation is associated with antibody-initiated, inflammatory diseases processes like cold agglutinin disease, acute intravascular hemolytic transfusion reaction (AIHTR), and acute/hyperacute transplantation rejection. To date, only one putative classical pathway inhibitor, C1 esterase inhibitor (C1-INH), is currently commercially available and its only approved indication is for replacement treatment in hereditary angioedema, which is predominantly a kinin pathway disease. Given the variety of disease conditions in which the classical pathway is implicated, development of therapeutics that specifically inhibits complement initiation represents a major unmet medical need. Our laboratory has identified a peptide that specifically inhibits the classical and lectin pathways of complement. In vitro studies have demonstrated that these peptide inhibitors of complement C1 (PIC1) bind to the collagen-like region of the initiator molecule of the classical pathway, C1q. PIC1 binding to C1q blocks activation of the associated serine proteases (C1s-C1r-C1r-C1s) and subsequent downstream complement activation. Rational design optimization of PIC1 has resulted in the generation of a highly potent derivative of 15 amino acids. PIC1 inhibits classical pathway mediated complement activation in ABO incompatibility in vitro and inhibiting classical pathway activation in vivo in rats. This review will focus on the pre-clinical development of PIC1 and discuss its potential as a therapeutic in antibody-mediated classical pathway disease, specifically AIHTR. PMID:25202312

  4. Peptide Inhibitor of Complement C1, a Novel Suppressor of Classical Pathway Activation: Mechanistic Studies and Clinical Potential

    PubMed Central

    Sharp, Julia A.; Whitley, Pamela H.; Cunnion, Kenji M.; Krishna, Neel K.

    2014-01-01

    The classical pathway of complement plays multiple physiological roles including modulating immunological effectors initiated by adaptive immune responses and an essential homeostatic role in the clearance of damaged self-antigens. However, dysregulated classical pathway activation is associated with antibody-initiated, inflammatory diseases processes like cold agglutinin disease, acute intravascular hemolytic transfusion reaction (AIHTR), and acute/hyperacute transplantation rejection. To date, only one putative classical pathway inhibitor, C1 esterase inhibitor (C1-INH), is currently commercially available and its only approved indication is for replacement treatment in hereditary angioedema, which is predominantly a kinin pathway disease. Given the variety of disease conditions in which the classical pathway is implicated, development of therapeutics that specifically inhibits complement initiation represents a major unmet medical need. Our laboratory has identified a peptide that specifically inhibits the classical and lectin pathways of complement. In vitro studies have demonstrated that these peptide inhibitors of complement C1 (PIC1) bind to the collagen-like region of the initiator molecule of the classical pathway, C1q. PIC1 binding to C1q blocks activation of the associated serine proteases (C1s–C1r–C1r–C1s) and subsequent downstream complement activation. Rational design optimization of PIC1 has resulted in the generation of a highly potent derivative of 15 amino acids. PIC1 inhibits classical pathway mediated complement activation in ABO incompatibility in vitro and inhibiting classical pathway activation in vivo in rats. This review will focus on the pre-clinical development of PIC1 and discuss its potential as a therapeutic in antibody-mediated classical pathway disease, specifically AIHTR. PMID:25202312

  5. A Novel Quantitative Hemolytic Assay Coupled with Restriction Fragment Length Polymorphisms Analysis Enabled Early Diagnosis of Atypical Hemolytic Uremic Syndrome and Identified Unique Predisposing Mutations in Japan

    PubMed Central

    Yoshida, Yoko; Miyata, Toshiyuki; Matsumoto, Masanori; Shirotani-Ikejima, Hiroko; Uchida, Yumiko; Ohyama, Yoshifumi; Kokubo, Tetsuro; Fujimura, Yoshihiro

    2015-01-01

    For thrombotic microangiopathies (TMAs), the diagnosis of atypical hemolytic uremic syndrome (aHUS) is made by ruling out Shiga toxin-producing Escherichia coli (STEC)-associated HUS and ADAMTS13 activity-deficient thrombotic thrombocytopenic purpura (TTP), often using the exclusion criteria for secondary TMAs. Nowadays, assays for ADAMTS13 activity and evaluation for STEC infection can be performed within a few hours. However, a confident diagnosis of aHUS often requires comprehensive gene analysis of the alternative complement activation pathway, which usually takes at least several weeks. However, predisposing genetic abnormalities are only identified in approximately 70% of aHUS. To facilitate the diagnosis of complement-mediated aHUS, we describe a quantitative hemolytic assay using sheep red blood cells (RBCs) and human citrated plasma, spiked with or without a novel inhibitory anti-complement factor H (CFH) monoclonal antibody. Among 45 aHUS patients in Japan, 24% (11/45) had moderate-to-severe (≥50%) hemolysis, whereas the remaining 76% (34/45) patients had mild or no hemolysis (<50%). The former group is largely attributed to CFH-related abnormalities, and the latter group has C3-p.I1157T mutations (16/34), which were identified by restriction fragment length polymorphism (RFLP) analysis. Thus, a quantitative hemolytic assay coupled with RFLP analysis enabled the early diagnosis of complement-mediated aHUS in 60% (27/45) of patients in Japan within a week of presentation. We hypothesize that this novel quantitative hemolytic assay would be more useful in a Caucasian population, who may have a higher proportion of CFH mutations than Japanese patients. PMID:25951460

  6. Complement Regulatory Activity of Normal Human Intraocular Fluid Is Mediated by MCP, DAF, and CD59

    PubMed Central

    Sohn, Jeong-Hyeon; Kaplan, Henry J.; Suk, Hye-Jung; Bora, Puran S.; Bora, Nalini S.

    2007-01-01

    Purpose To identify the molecules in normal human intraocular fluid (aqueous humor and vitreous) that inhibit the functional activity of the complement system. Methods Aqueous humor and vitreous were obtained from patients with noninflammatory ocular disease at the time of surgery. Samples were incubated with normal human serum (NHS), and the mixture assayed for inhibition of the classical and alternative complement pathways using standard CH50 and AH50 hemolytic assays, respectively. Both aqueous humor and vitreous were fractionated by microconcentrators and size exclusion column chromatography. The inhibitory molecules were identified by immunoblotting as well as by studying the effect of depletion of membrane cofactor protein (MCP), decay-accelerating factor (DAF), and CD59 on inhibitory activity. Results Both aqueous humor and vitreous inhibited the activity of the classical pathway (CH50). Microcentrifugation revealed the major inhibitory activity resided in the fraction with an Mr ≥ 3 kDa. Chromatography on an S-100-HR column demonstrated that the most potent inhibition was associated with the high-molecular-weight fractions (≥ 19.5 kDa). In contrast to unfractionated aqueous and vitreous, fractions with an Mr ≥ 3 kDa also had an inhibitory effect on the alternative pathway activity (AH50). The complement regulatory activity in normal human intraocular fluid was partially blocked by monoclonal antibodies against MCP, DAF, and CD59. Immunoblot analysis confirmed the presence of these three molecules in normal intraocular fluid. Conclusions Our results demonstrate that normal human intraocular fluid (aqueous humor and vitreous) contains complement inhibitory factors. Furthermore, the high-molecular-weight factors appear to be the soluble forms of MCP, DAF, and CD59. PMID:11095615

  7. Characteristics of hemolytic activity induced by skin secretions of the frog Kaloula pulchra hainana

    PubMed Central

    2013-01-01

    Background The hemolytic activity of skin secretions obtained by stimulating the frog Kaloula pulchra hainana with diethyl ether was tested using human, cattle, rabbit, and chicken erythrocytes. The skin secretions had a significant concentration-dependent hemolytic effect on erythrocytes. The hemolytic activity of the skin secretions was studied in the presence of osmotic protectants (polyethylene glycols and carbohydrates), cations (Mg2+, Ca2+, Ba2+, Cu2+, and K+), or antioxidants (ascorbic acid, reduced glutathione, and cysteine). Results Depending on their molecular mass, osmotic protectants effectively inhibited hemolysis. The inhibition of skin hemolysis was observed after treatment with polyethylene glycols (1000, 3400, and 6000 Da). Among divalent cations, only 1 mM Cu2+ markedly inhibited hemolytic activity. Antioxidant compounds slightly reduced the hemolytic activity. Conclusions The results suggested that skin secretions of K. pulchra hainana induce a pore-forming mechanism to form pores with a diameter of 1.36-2.0 nm rather than causing oxidative damage to the erythrocyte membrane. PMID:24499077

  8. Update on hemolytic uremic syndrome: Diagnostic and therapeutic recommendations

    PubMed Central

    Salvadori, Maurizio; Bertoni, Elisabetta

    2013-01-01

    Hemolytic uremic syndrome (HUS) is a rare disease. In this work the authors review the recent findings on HUS, considering the different etiologic and pathogenetic classifications. New findings in genetics and, in particular, mutations of genes that encode the complement-regulatory proteins have improved our understanding of atypical HUS. Similarly, the complement proteins are clearly involved in all types of thrombotic microangiopathy: typical HUS, atypical HUS and thrombotic thrombocytopenic purpura (TTP). Furthermore, several secondary HUS appear to be related to abnormalities in complement genes in predisposed patients. The authors highlight the therapeutic aspects of this rare disease, examining both “traditional therapy” (including plasma therapy, kidney and kidney-liver transplantation) and “new therapies”. The latter include anti-Shiga-toxin antibodies and anti-C5 monoclonal antibody “eculizumab”. Eculizumab has been recently launched for the treatment of the atypical HUS, but it appears to be effective in the treatment of typical HUS and in TTP. Future therapies are in phases I and II. They include anti-C5 antibodies, which are more purified, less immunogenic and absorbed orally and, anti-C3 antibodies, which are more powerful, but potentially less safe. Additionally, infusions of recombinant complement-regulatory proteins are a potential future therapy. PMID:24255888

  9. Physicochemical signatures of nanoparticle-dependent complement activation

    SciTech Connect

    Thomas, Dennis G.; Chikkagoudar, Satish; Heredia-Langner, Alejandro; Tardiff, Mark F.; Xu, Zhixiang; Hourcade, Dennis; Pham, Christine; Lanza, Gregory M.; Weinberger, Kilian Q.; Baker, Nathan A.

    2014-03-21

    Nanoparticles are potentially powerful therapeutic tools that have the capacity to target drug payloads and imaging agents. However, some nanoparticles can activate complement, a branch of the innate immune system, and cause adverse side-effects. Recently, we developed an in vitro hemolytic assay protocol for measuring the nanoparticle-dependent complement activity of serum samples and applied this protocol to several nanoparticle formulations that differed in size, surface charge, and surface chemistry; quantifying the nanoparticle-dependent complement activity using a metric called Residual Hemolytic Activity (RHA). In the present work, we have used a decision tree learning algorithm to derive the rules for estimating nanoparticle-dependent complement response based on the data generated from the hemolytic assay studies. Our results indicate that physicochemical properties of nanoparticles, namely, size, polydispersity index, zeta potential, and mole percentage of the active surface ligand of a nanoparticle, can serve as good descriptors for prediction of nanoparticle-dependent complement activation in the decision tree modeling framework. The robustness and predictability of the model can be improved by training the model with additional data points that are uniformly distributed in the RHA/physicochemical descriptor space and by incorporating instability effects on nanoparticle physicochemical properties into the model.

  10. Combined Inhibition of Complement and CD14 Attenuates Bacteria-Induced Inflammation in Human Whole Blood More Efficiently Than Antagonizing the Toll-like Receptor 4–MD2 Complex

    PubMed Central

    Gustavsen, Alice; Nymo, Stig; Landsem, Anne; Christiansen, Dorte; Ryan, Liv; Husebye, Harald; Lau, Corinna; Pischke, Søren E.; Lambris, John D.; Espevik, Terje; Mollnes, Tom E.

    2016-01-01

    Background. Single inhibition of the Toll-like receptor 4 (TLR4)–MD2 complex failed in treatment of sepsis. CD14 is a coreceptor for several TLRs, including TLR4 and TLR2. The aim of this study was to investigate the effect of single TLR4-MD2 inhibition by using eritoran, compared with the effect of CD14 inhibition alone and combined with the C3 complement inhibitor compstatin (Cp40), on the bacteria-induced inflammatory response in human whole blood. Methods. Cytokines were measured by multiplex technology, and leukocyte activation markers CD11b and CD35 were measured by flow cytometry. Results. Lipopolysaccharide (LPS)–induced inflammatory markers were efficiently abolished by both anti-CD14 and eritoran. Anti-CD14 was significantly more effective than eritoran in inhibiting LPS-binding to HEK-293E cells transfected with CD14 and Escherichia coli–induced upregulation of monocyte activation markers (P < .01). Combining Cp40 with anti-CD14 was significantly more effective than combining Cp40 with eritoran in reducing E. coli–induced interleukin 6 (P < .05) and monocyte activation markers induced by both E. coli (P < .001) and Staphylococcus aureus (P < .01). Combining CP40 with anti-CD14 was more efficient than eritoran alone for 18 of 20 bacteria-induced inflammatory responses (mean P < .0001). Conclusions. Whole bacteria–induced inflammation was inhibited more efficiently by anti-CD14 than by eritoran, particularly when combined with complement inhibition. Combined CD14 and complement inhibition may prove a promising treatment strategy for bacterial sepsis. PMID:26977050

  11. Terminal Complement Blockade after Hematopoietic Stem Cell Transplantation Is Safe without Meningococcal Vaccination.

    PubMed

    Jodele, Sonata; Dandoy, Christopher E; Danziger-Isakov, Lara; Myers, Kasiani C; El-Bietar, Javier; Nelson, Adam; Wallace, Gregory; Teusink-Cross, Ashley; Davies, Stella M

    2016-07-01

    Eculizumab inhibits terminal complement-mediated intravascular hemolysis in patients with paroxysmal nocturnal hemoglobinuria and complement-mediated thrombotic microangiopathy (TMA) in patients with atypical hemolytic uremic syndrome and is now used as a first-line therapy in these diseases. Eculizumab is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS) because of an increased risk of meningococcal infections in persons without adequate functional complement. Administration of meningococcal vaccine is required at least 2 weeks before administering the first dose of eculizumab, and this advice is included in the product label. Eculizumab use for treatment of TMA in hematopoietic stem cell transplantation (HSCT) recipients brings a significant dilemma regarding REMS required meningococcal vaccination. TMA after HSCT usually occurs within the first 100 days after transplantation when patients are severely immunocompromised and are not able to mount a response to vaccines. We evaluated 30 HSCT recipients treated with eculizumab for high-risk TMA without meningococcal vaccine. All patients received antimicrobial prophylaxis adequate for Neisseria meningitides during eculizumab therapy and for 8 weeks after discontinuation of the drug. Median time to TMA diagnosis was 28 days after transplant (range, 13.8 to 48.5). Study subjects received a median of 14 eculizumab doses (range, 2 to 38 doses) for HSCT-associated TMA therapy. There were no incidences of meningococcal infections. The incidences of bacterial and fungal bloodstream infections were similar in patients treated with eculizumab (n = 30) as compared with those with HSCT-associated TMA who did not receive any complement blocking therapy (n = 39). Our data indicate that terminal complement blockade in the early post-transplant period can be performed without meningococcal vaccination while using appropriate antimicrobial prophylaxis until complement

  12. Deficiency of complement component 5 ameliorates glaucoma in DBA/2J mice

    PubMed Central

    2013-01-01

    Background Glaucoma is an age-related neurodegenerative disorder involving the loss of retinal ganglion cells (RGCs), which results in blindness. Studies in animal models have shown that activation of inflammatory processes occurs early in the disease. In particular, the complement cascade is activated very early in DBA/2J mice, a widely used mouse model of glaucoma. A comprehensive analysis of the role of the complement cascade in DBA/2J glaucoma has not been possible because DBA/2J mice are naturally deficient in complement component 5 (C5, also known as hemolytic complement, Hc), a key mediator of the downstream processes of the complement cascade, including the formation of the membrane attack complex. Methods To assess the role of C5 in DBA/2J glaucoma, we backcrossed a functional C5 gene from strain C57BL/6J to strain DBA/2J for at least 10 generations. The prevalence and severity of glaucoma was evaluated using ocular examinations, IOP measurements, and assessments of optic nerve damage and RGC degeneration. To understand how C5 affects glaucoma, C5 expression was assessed in the retinas and optic nerves of C5-sufficient DBA/2J mice, using immunofluorescence. Results C5-sufficient DBA/2J mice developed a more severe glaucoma at an earlier age than standard DBA/2J mice, which are therefore protected by C5 deficiency. Components of the membrane attack complex were found to be deposited at sites of axonal injury in the optic nerve head and associated with RGC soma in the retina. Conclusion C5 plays an important role in glaucoma, with its deficiency lessening disease severity. These results highlight the importance of fully understanding the role of the complement cascade in neurodegenerative diseases. Inhibiting C5 may be beneficial as a therapy for human glaucoma. PMID:23806181

  13. Novel hemagglutinating, hemolytic and cytotoxic activities of the intermediate subunit of Entamoeba histolytica lectin

    PubMed Central

    Kato, Kentaro; Yahata, Kazuhide; Gopal Dhoubhadel, Bhim; Fujii, Yoshito; Tachibana, Hiroshi

    2015-01-01

    Galactose and N-acetyl-D-galactosamine (Gal/GalNAc) inhibitable lectin of Entamoeba histolytica, a common protozoan parasite, has roles in pathogenicity and induction of protective immunity in mouse models of amoebiasis. The lectin consists of heavy (Hgl), light (Lgl), and intermediate (Igl) subunits. Hgl has lectin activity and Lgl does not, but little is known about the activity of Igl. In this study, we assessed various regions of Igl for hemagglutinating activity using recombinant proteins expressed in Escherichia coli. We identified a weak hemagglutinating activity of the protein. Furthermore, we found novel hemolytic and cytotoxic activities of the lectin, which resided in the carboxy-terminal region of the protein. Antibodies against Igl inhibited the hemolytic activity of Entamoeba histolytica trophozoites. This is the first report showing hemagglutinating, hemolytic and cytotoxic activities of an amoebic molecule, Igl. PMID:26354528

  14. Clinical Practice Guidelines for the Management of Atypical Hemolytic Uremic Syndrome in Korea.

    PubMed

    Cheong, Hae Il; Jo, Sang Kyung; Yoon, Sung Soo; Cho, Heeyeon; Kim, Jin Seok; Kim, Young Ok; Koo, Ja Ryong; Park, Yong; Park, Young Seo; Shin, Jae Il; Yoo, Kee Hwan; Oh, Doyeun

    2016-10-01

    Atypical hemolytic uremic syndrome (aHUS) is a rare syndrome characterized by micro-angiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. The major pathogenesis of aHUS involves dysregulation of the complement system. Eculizumab, which blocks complement C5 activation, has recently been proven as an effective agent. Delayed diagnosis and treatment of aHUS can cause death or end-stage renal disease. Therefore, a diagnosis that differentiates aHUS from other forms of thrombotic microangiopathy is very important for appropriate management. These guidelines aim to offer recommendations for the diagnosis and treatment of patients with aHUS in Korea. The guidelines have largely been adopted from the current guidelines due to the lack of evidence concerning the Korean population. PMID:27550478

  15. Complement System Part II: Role in Immunity

    PubMed Central

    Merle, Nicolas S.; Noe, Remi; Halbwachs-Mecarelli, Lise; Fremeaux-Bacchi, Veronique; Roumenina, Lubka T.

    2015-01-01

    The complement system has been considered for a long time as a simple lytic cascade, aimed to kill bacteria infecting the host organism. Nowadays, this vision has changed and it is well accepted that complement is a complex innate immune surveillance system, playing a key role in host homeostasis, inflammation, and in the defense against pathogens. This review discusses recent advances in the understanding of the role of complement in physiology and pathology. It starts with a description of complement contribution to the normal physiology (homeostasis) of a healthy organism, including the silent clearance of apoptotic cells and maintenance of cell survival. In pathology, complement can be a friend or a foe. It acts as a friend in the defense against pathogens, by inducing opsonization and a direct killing by C5b–9 membrane attack complex and by triggering inflammatory responses with the anaphylatoxins C3a and C5a. Opsonization plays also a major role in the mounting of an adaptive immune response, involving antigen presenting cells, T-, and B-lymphocytes. Nevertheless, it can be also an enemy, when pathogens hijack complement regulators to protect themselves from the immune system. Inadequate complement activation becomes a disease cause, as in atypical hemolytic uremic syndrome, C3 glomerulopathies, and systemic lupus erythematosus. Age-related macular degeneration and cancer will be described as examples showing that complement contributes to a large variety of conditions, far exceeding the classical examples of diseases associated with complement deficiencies. Finally, we discuss complement as a therapeutic target. PMID:26074922

  16. Polyphosphate suppresses complement via the terminal pathway

    PubMed Central

    Wat, Jovian M.; Foley, Jonathan H.; Krisinger, Michael J.; Ocariza, Linnette Mae; Lei, Victor; Wasney, Gregory A.; Lameignere, Emilie; Strynadka, Natalie C.; Smith, Stephanie A.; Morrissey, James H.

    2014-01-01

    Polyphosphate, synthesized by all cells, is a linear polymer of inorganic phosphate. When released into the circulation, it exerts prothrombotic and proinflammatory activities by modulating steps in the coagulation cascade. We examined the role of polyphosphate in regulating the evolutionarily related proteolytic cascade complement. In erythrocyte lysis assays, polyphosphate comprising more than 1000 phosphate units suppressed total hemolytic activity with a concentration to reduce maximal lysis to 50% that was 10-fold lower than with monophosphate. In the ion- and enzyme-independent terminal pathway complement assay, polyphosphate suppressed complement in a concentration- and size-dependent manner. Phosphatase-treated polyphosphate lost its ability to suppress complement, confirming that polymer integrity is required. Sequential addition of polyphosphate to the terminal pathway assay showed that polyphosphate interferes with complement only when added before formation of the C5b-7 complex. Physicochemical analyses using native gels, gel filtration, and differential scanning fluorimetry revealed that polyphosphate binds to and destabilizes C5b,6, thereby reducing the capacity of the membrane attack complex to bind to and lyse the target cell. In summary, we have added another function to polyphosphate in blood, demonstrating that it dampens the innate immune response by suppressing complement. These findings further establish the complex relationship between coagulation and innate immunity. PMID:24335501

  17. Recessive mutations in DGKE cause atypical hemolytic-uremic syndrome

    PubMed Central

    Lemaire, Mathieu; Frémeaux-Bacchi, Véronique; Schaefer, Franz; Choi, Murim; Tang, Wai Ho; Le Quintrec, Moglie; Fakhouri, Fadi; Taque, Sophie; Nobili, François; Martinez, Frank; Ji, Weizhen; Overton, John D.; Mane, Shrikant M.; Nürnberg, Gudrun; Altmüller, Janine; Thiele, Holger; Morin, Denis; Deschenes, Georges; Baudouin, Véronique; Llanas, Brigitte; Collard, Laure; Majid, Mohammed A.; Simkova, Eva; Nürnberg, Peter; Rioux-Leclerc, Nathalie; Moeckel, Gilbert W.; Gubler, Marie Claire; Hwa, John; Loirat, Chantal; Lifton, Richard P.

    2013-01-01

    Pathologic thrombosis is a major cause of mortality. Hemolytic-uremic syndrome (HUS) features episodes of small vessel thrombosis resulting in microangiopathic hemolytic anemia, thrombocytopenia and renal failure1. Atypical HUS (aHUS) can result from genetic or autoimmune factors2 that lead to pathologic complement cascade activation3. By exome sequencing we identify recessive mutations in DGKE (diacylglycerol kinase epsilon) that co-segregate with aHUS in 9 unrelated kindreds, defining a distinctive Mendelian disease. Affected patients present with aHUS before age 1, have persistent hypertension, hematuria and proteinuria (sometimes nephrotic range), and develop chronic kidney disease with age. DGKE is found in endothelium, platelets, and podocytes. Arachidonic acid-containing diacylglycerols (DAG) activate protein kinase C, which promotes thrombosis. DGKE normally inactivates DAG signaling. We infer that loss of DGKE function results in a pro-thrombotic state. These findings identify a new mechanism of pathologic thrombosis and kidney failure and have immediate implications for treatment of aHUS patients. PMID:23542698

  18. Renal cell carcinoma and autoimmune hemolytic anemia.

    PubMed

    Lands, R; Foust, J

    1996-04-01

    A previously healthy man who became bedridden because of malaise, fatigue, and weakness was found to have an autoimmune hemolytic anemia (AIHA). In the course of his evaluation for the AIHA, he was found, coincidentally, to have a renal cell carcinoma. The AIHA was marginally responsive to therapy with corticosteroids, but it resolved promptly after excision of the cancer. This case represents probably a rarely observed association between a nonhematologic malignancy and autoimmune hemolytic anemia. PMID:8614893

  19. [Atypical HUS caused by complement-related abnormalities].

    PubMed

    Yoshida, Yoko; Matsumoto, Masanori

    2015-02-01

    Atypical hemolytic uremic syndrome (aHUS) is a rare disease characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. The term aHUS was historically used to distinguish this disorder from Shiga-toxin producing Escherichia coli (STEC)-HUS. Many aHUS cases (approximately 70%) are reportedly caused by uncontrolled complement activation due to genetic mutations in the alternative pathway, including complement factor H (CFH), complement factor I (CFI), membrane cofactor protein (MCP), thrombomodulin (THBD), complement component C3 (C3), and complement factor B (CFB). Mutations in the coagulation pathway, such as diacylglycerol kinase ε (DGKE) and plasminogen, are also reported to be causes of aHUS. In this review, we have focused on aHUS due to complement dysfunction. aHUS is suspected based on plasma ADAMTS13 activity of 10% or more, and being negative for STEC-HUS, in addition to the aforementioned triad. Complement genetic studies provide a more specific diagnosis of aHUS. Plasma therapy is the first-line treatment for patients with aHUS and should be initiated as soon as the diagnosis is suspected. Recently, eculizumab, a humanized monoclonal antibody against C5, was shown to be an effective treatment for aHUS. Therefore, early diagnosis and identification of the underlying pathogenic mechanism is important for improving the outcome of aHUS. PMID:25765799

  20. Factor H–Related Protein 5 Interacts with Pentraxin 3 and the Extracellular Matrix and Modulates Complement Activation

    PubMed Central

    Csincsi, Ádám I.; Kopp, Anne; Zöldi, Miklós; Bánlaki, Zsófia; Uzonyi, Barbara; Hebecker, Mario; Caesar, Joseph J. E.; Pickering, Matthew C.; Daigo, Kenji; Hamakubo, Takao; Lea, Susan M.; Goicoechea de Jorge, Elena

    2015-01-01

    The physiological roles of the factor H (FH)-related proteins are controversial and poorly understood. Based on genetic studies, FH-related protein 5 (CFHR5) is implicated in glomerular diseases, such as atypical hemolytic uremic syndrome, dense deposit disease, and CFHR5 nephropathy. CFHR5 was also identified in glomerular immune deposits at the protein level. For CFHR5, weak complement regulatory activity and competition for C3b binding with the plasma complement inhibitor FH have been reported, but its function remains elusive. In this study, we identify pentraxin 3 (PTX3) as a novel ligand of CFHR5. Binding of native CFHR5 to PTX3 was detected in human plasma and the interaction was characterized using recombinant proteins. The binding of PTX3 to CFHR5 is of ∼2-fold higher affinity compared with that of FH. CFHR5 dose-dependently inhibited FH binding to PTX3 and also to the monomeric, denatured form of the short pentraxin C–reactive protein. Binding of PTX3 to CFHR5 resulted in increased C1q binding. Additionally, CFHR5 bound to extracellular matrix in vitro in a dose-dependent manner and competed with FH for binding. Altogether, CFHR5 reduced FH binding and its cofactor activity on pentraxins and the extracellular matrix, while at the same time allowed for enhanced C1q binding. Furthermore, CFHR5 allowed formation of the alternative pathway C3 convertase and supported complement activation. Thus, CFHR5 may locally enhance complement activation via interference with the complement-inhibiting function of FH, by enhancement of C1q binding, and by activating complement, thereby contributing to glomerular disease. PMID:25855355

  1. Treatment of autoimmune hemolytic anemias

    PubMed Central

    Zanella, Alberto; Barcellini, Wilma

    2014-01-01

    Autoimmune hemolytic anemia (AIHA) is a relatively uncommon disorder caused by autoantibodies directed against self red blood cells. It can be idiopathic or secondary, and classified as warm, cold (cold hemagglutinin disease (CAD) and paroxysmal cold hemoglobinuria) or mixed, according to the thermal range of the autoantibody. AIHA may develop gradually, or have a fulminant onset with life-threatening anemia. The treatment of AIHA is still not evidence-based. The first-line therapy for warm AIHA are corticosteroids, which are effective in 70–85% of patients and should be slowly tapered over a time period of 6–12 months. For refractory/relapsed cases, the current sequence of second-line therapy is splenectomy (effective approx. in 2 out of 3 cases but with a presumed cure rate of up to 20%), rituximab (effective in approx. 80–90% of cases), and thereafter any of the immunosuppressive drugs (azathioprine, cyclophosphamide, cyclosporin, mycophenolate mofetil). Additional therapies are intravenous immunoglobulins, danazol, plasma-exchange, and alemtuzumab and high-dose cyclophosphamide as last resort option. As the experience with rituximab evolves, it is likely that this drug will be located at an earlier point in therapy of warm AIHA, before more toxic immunosuppressants, and in place of splenectomy in some cases. In CAD, rituximab is now recommended as first-line treatment. PMID:25271314

  2. Atypical Hemolytic Uremic Syndrome and Chronic Ulcerative Colitis Treated with Eculizumab

    PubMed Central

    Webb, Tennille N.; Griffiths, Heidi; Miyashita, Yosuke; Bhatt, Riha; Jaffe, Ronald; Moritz, Michael; Hofer, Johannes; Swiatecka-Urban, Agnieszka

    2016-01-01

    Background Hemolytic-uremic syndrome (HUS) presents with hemolytic anemia, thrombocytopenia, and thrombotic microangiopathy of the kidney and usually results from Shiga-toxin induced activation of the alternative complement pathway. Gastroenteritis is a common feature of the Shiga-toxin producing Escherichia coli HUS, referred to as STEC-HUS. An inherited or acquired complement dysregulation may lead to HUS referred to as non-STEC or atypical (a)HUS. Although gastroenteritis is not a common presentation of aHUS, some patients develop ischemic colitis and may be misdiagnosed as acute appendicitis or acute ulcerative colitis (UC). Case Diagnosis –Treatment We present a patient with low circulating complement (C) 3 levels who developed aHUS in the course of chronic active UC. Resolution of renal and gastrointestinal manifestations in response to treatment with eculizumab, a humanized monoclonal antibody against terminal C5 protein suggests the role of alternative complement in the pathogenesis of both, aHUS and UC. Conclusion This case illustrates that dysregulation of the alternative complement pathway may manifest in other organs besides the kidney and that the circulating C3 levels do not correlate with the disease activity or the clinical response to eculizumab. PMID:27135055

  3. A Case of Atypical Hemolytic Uremic Syndrome Successfully Treated with Eculizumab

    PubMed Central

    Thajudeen, B.; Sussman, A.; Bracamonte, E.

    2013-01-01

    Atypical hemolytic uremic syndrome (aHUS) is a rare thrombotic microangiopathy (TMA) characterized by the triad of hemolytic anemia, thrombocytopenia, and acute renal failure. Eculizumab, a monoclonal complement C5 antibody which prevents the induction of the terminal complement cascade, has recently emerged as a therapeutic option for aHUS. We report a case of aHUS successfully treated with eculizumab. A 51-year-old male was admitted to the hospital following a mechanical fall. His past medical history was significant for rheumatic valve disease and mitral valve replacement; he was on warfarin for anticoagulation. A computed tomography scan of the head revealed a right-sided subdural hematoma due to coagulopathy resulting from a supratherapeutic international normalized ratio (INR). Following treatment with prothrombin complex concentrate to reverse the INR, urine output dropped and his serum creatinine subsequently increased to 247.52 μmol/l from the admission value of 70.72 μmol/l. Laboratory evaluation was remarkable for hemolytic anemia, thrombocytopenia, elevated lactate dehydrogenase (LDH), low haptoglobin, and low complement C3. A renal biopsy was consistent with TMA, favoring a diagnosis of aHUS. Treatment with eculizumab was initiated which resulted in the stabilization of his hemoglobin, platelets, and LDH. Hemodialysis was terminated after 2.5 months due to improvement in urine output and solute clearance. The interaction between thrombin and complement pathway might be responsible for the pathogenesis of aHUS in this case. Eculizumab is an effective therapeutic agent in the treatment of aHUS. Early targeting of the complement system may modify disease progression and thus treat aHUS more effectively. PMID:24570684

  4. Biochemical and physiological analyses of a hemolytic toxin isolated from a sea anemone Actineria villosa.

    PubMed

    Uechi, Gen-Ichiro; Toma, Hiromu; Arakawa, Takeshi; Sato, Yoshiya

    2005-05-01

    A species of venomous sea anemone Actineria villosa was recently found inhabiting the coastal areas of Okinawa, Japan. This marine animal produces various proteinous toxins, so that a local health organization was called for medical treatment for those who had accidental contact with this animal. In this study we analyzed the biochemical and physiological properties of hemolytic protein from A. villosa. The toxin purified from the tentacles of the animals was found to be a protein with a molecular weight of approximately 19 kDa. We named this newly found hemolytic toxin of A. villosa, Avt-I. Incubation of the toxin with sphingomyelin inhibited hemolytic activity by up to 85%, showing that Avt-I may target sphingomyelin on the erythrocyte membrane. The hemolytic activity was stably maintained at temperatures below 45 degrees C, however, a sharp linear decrease in heat stability was observed within the range of 45-55 degrees C. Our results provide the first evidence that A. villosa produces a toxin with strong hemolytic activity similar in biochemical and physiological properties to other members of actinoporin family previously isolated from related species of sea anemones. PMID:15804525

  5. Complement factor H related proteins (CFHRs).

    PubMed

    Skerka, Christine; Chen, Qian; Fremeaux-Bacchi, Veronique; Roumenina, Lubka T

    2013-12-15

    Factor H related proteins comprise a group of five plasma proteins: CFHR1, CFHR2, CFHR3, CFHR4 and CFHR5, and each member of this group binds to the central complement component C3b. Mutations, genetic deletions, duplications or rearrangements in the individual CFHR genes are associated with a number of diseases including atypical hemolytic uremic syndrome (aHUS), C3 glomerulopathies (C3 glomerulonephritis (C3GN), dense deposit disease (DDD) and CFHR5 nephropathy), IgA nephropathy, age related macular degeneration (AMD) and systemic lupus erythematosus (SLE). Although complement regulatory functions were attributed to most of the members of the CFHR protein family, the precise role of each CFHR protein in complement activation and the exact contribution to disease pathology is still unclear. Recent publications show that CFHR proteins form homo- as well as heterodimers. Genetic abnormalities within the CFHR gene locus can result in hybrid proteins with affected dimerization or recognition domains which cause defective functions. Here we summarize the recent data about CFHR genes and proteins in order to better understand the role of CFHR proteins in complement activation and in complement associated diseases. PMID:23830046

  6. Extra-Renal Manifestations of Complement-Mediated Thrombotic Microangiopathies

    PubMed Central

    Hofer, Johannes; Rosales, Alejandra; Fischer, Caroline; Giner, Thomas

    2014-01-01

    Thrombotic microangiopathies (TMA) are rare but severe disorders, characterized by endothelial cell activation and thrombus formation leading to hemolytic anemia, thrombocytopenia, and organ failure. Complement over activation in combination with defects in its regulation is described in an increasing number of TMA and if primary for the disease denominated as atypical hemolytic-uremic syndrome. Although TMA predominantly affects the renal microvasculature, extra-renal manifestations are observed in 20% of patients including involvement of the central nerve system, cardiovascular system, lungs, skin, skeletal muscle, and gastrointestinal tract. Prompt diagnosis and treatment initiation are therefore crucial for the prognosis of disease acute phase and the long-term outcome. This review summarizes the available evidence on extra-renal TMA manifestations and discusses the role of acute and chronic complement activation by highlighting its complex interaction with inflammation, coagulation, and endothelial homeostasis. PMID:25250305

  7. Methods for quantitative detection of antibody-induced complement activation on red blood cells.

    PubMed

    Meulenbroek, Elisabeth M; Wouters, Diana; Zeerleder, Sacha

    2014-01-01

    Antibodies against red blood cells (RBCs) can lead to complement activation resulting in an accelerated clearance via complement receptors in the liver (extravascular hemolysis) or leading to intravascular lysis of RBCs. Alloantibodies (e.g. ABO) or autoantibodies to RBC antigens (as seen in autoimmune hemolytic anemia, AIHA) leading to complement activation are potentially harmful and can be - especially when leading to intravascular lysis - fatal(1). Currently, complement activation due to (auto)-antibodies on RBCs is assessed in vitro by using the Coombs test reflecting complement deposition on RBC or by a nonquantitative hemolytic assay reflecting RBC lysis(1-4). However, to assess the efficacy of complement inhibitors, it is mandatory to have quantitative techniques. Here we describe two such techniques. First, an assay to detect C3 and C4 deposition on red blood cells that is induced by antibodies in patient serum is presented. For this, FACS analysis is used with fluorescently labeled anti-C3 or anti-C4 antibodies. Next, a quantitative hemolytic assay is described. In this assay, complement-mediated hemolysis induced by patient serum is measured making use of spectrophotometric detection of the released hemoglobin. Both of these assays are very reproducible and quantitative, facilitating studies of antibody-induced complement activation. PMID:24514151

  8. Solid-phase classical complement activation by C-reactive protein (CRP) is inhibited by fluid-phase CRP-C1q interaction

    SciTech Connect

    Sjoewall, Christopher; Askendal, Agneta; Almroth, Gunnel

    2007-01-05

    C-reactive protein (CRP) interacts with phosphorylcholine (PC), Fc{gamma} receptors, complement factor C1q and cell nuclear constituents, yet its biological roles are insufficiently understood. The aim was to characterize CRP-induced complement activation by ellipsometry. PC conjugated with keyhole limpet hemocyanin (PC-KLH) was immobilized to cross-linked fibrinogen. A low-CRP serum with different amounts of added CRP was exposed to the PC-surfaces. The total serum protein deposition was quantified and deposition of IgG, C1q, C3c, C4, factor H, and CRP detected with polyclonal antibodies. The binding of serum CRP to PC-KLH dose-dependently triggered activation of the classical pathway. Unexpectedly, the activation was efficiently down-regulated at CRP levels >150 mg/L. Using radial immunodiffusion, CRP-C1q interaction was observed in serum samples with high CRP concentrations. We propose that the underlying mechanism depends on fluid-phase interaction between C1q and CRP. This might constitute another level of complement regulation, which has implications for systemic lupus erythematosus where CRP is often low despite flare-ups.

  9. The OspE-Related Proteins Inhibit Complement Deposition and Enhance Serum Resistance of Borrelia burgdorferi, the Lyme Disease Spirochete ▿

    PubMed Central

    Kenedy, Melisha R.; Akins, Darrin R.

    2011-01-01

    Borrelia burgdorferi, the Lyme disease spirochete, binds the host complement inhibitors factor H (FH) and FH-like protein 1 (FHL-1). Binding of FH/FHL-1 by the B. burgdorferi proteins CspA and the OspE-related proteins is thought to enhance resistance to serum-mediated killing. While previous reports have shown that CspA confers serum resistance in B. burgdorferi, it is unclear whether the OspE-related proteins are relevant in B. burgdorferi serum resistance when OspE is expressed on the borrelial surface. To assess the role of the OspE-related proteins, we overexpressed them in a serum-sensitive CspA mutant strain. OspE overexpression enhanced serum resistance of the CspA-deficient organisms. Furthermore, FH was more efficiently bound to the B. burgdorferi surface when OspE was overexpressed. Deposition of complement components C3 and C5b-9 (the membrane attack complex), however, was reduced on the surface of the OspE-overexpressing strain compared to that on the CspA mutant strain. These data demonstrate that OspE proteins expressed on the surface of B. burgdorferi bind FH and protect the organism from complement deposition and subsequent serum-mediated destruction. PMID:21282413

  10. Mount St. Helens' volcanic ash: hemolytic activity.

    PubMed

    Vallyathan, V; Mentnech, M S; Stettler, L E; Dollberg, D D; Green, F H

    1983-04-01

    Volcanic ash samples from four Mount St. Helens' volcanic eruptions were subjected to mineralogical, analytical, and hemolytic studies in order to evaluate their potential for cytotoxicity and fibrogenicity. Plagioclase minerals constituted the major component of the ash with free crystalline silica concentrations ranging from 1.5 to 7.2%. The in vitro hemolytic activity of the volcanic ash was compared to similar concentrations of cytotoxic and inert minerals. The ash was markedly hemolytic, exhibiting an activity similar to chrysotile asbestos, a known fibrogenic agent. The hemolysis of the different ash samples varied with particle size but not with crystalline silica concentration. The results of these studies taken in conjunction with the results of our animal studies indicate a fibrogenic potential of volcanic ash in heavily exposed humans. PMID:6832120

  11. Hemolytic uremic syndrome and rhabdomyolysis in a patient with succinate coenzyme Q reductase (complex II) deficiency.

    PubMed

    Micheletti, M V; Lavoratti, G; Gasperini, S; Donati, M A; Pela, I

    2011-07-01

    Hemolytic uremic syndrome (HUS) is characterized by microangiopathic hemolytic anemia, thrombocytopenia and acute renal failure. Besides diarrhea-associated HUS, due to verotoxin-producing Escherichia coli, in children HUS without prodromal diarrhea may be associated with other infectious and autoimmune diseases, genetic defects of the complement-regulator alternative-pathway, and inborn errors of vitamin B12 metabolism. Rhabdomyolysis is the dissolution of skeletal muscle due to various causes, including inborn errors of metabolism. Recurrent rhabdomyolysis and HUS have been previously described in one patient with a genetic defect of oxidative phosphorylation. We report the case of a 2-year-old boy with recurrent HUS and rhabdomyolysis in whom a succinate coenzyme Q reductase (complex II) deficiency was diagnosed. We hypothesize that defects of oxidative phosphorylation could be another etiological factor in atypical HUS. PMID:21722608

  12. Blockade of C5a and C5b-9 generation inhibits leukocyte and platelet activation during extracorporeal circulation.

    PubMed Central

    Rinder, C S; Rinder, H M; Smith, B R; Fitch, J C; Smith, M J; Tracey, J B; Matis, L A; Squinto, S P; Rollins, S A

    1995-01-01

    Complement activation contributes to the systemic inflammatory response induced by cardiopulmonary bypass. At the cellular level, cardiopulmonary bypass activates leukocytes and platelets; however the contribution of early (3a) versus late (C5a, soluble C5b-9) complement components to this activation is unclear. We used a model of simulated extracorporeal circulation that activates complement (C3a, C5a, and C5b-9 formation), platelets (increased percentages of P-selectin-positive platelets and leukocyte-platelet conjugates), and neutrophils (upregulated CD11b expression). to specifically target complement activation in this model, we added a blocking mAb directed at the human C5 complement component and assessed its effect on complement and cellular activation. Compared with a control mAB, the anti-human C5 mAb profoundly inhibited C5a and soluble C5b-9 generation and serum complement hemolytic activity but had no effect on C3a generation. Additionally, the anti-human C5 mAb significantly inhibited neutrophil CD11b upregulation and abolished the increase in P-selectin-positive platelets and leukocyte-platelet conjugate formation compared to experiments performed with the control mAb. This suggests that the terminal components C5a and C5b-9, but not C3a, directly contribute to platelet and neutrophil activation during extracorporeal circulation. Furthermore, these data identify the C5 component as a site for therapeutic intervention in cardiopulmonary bypass. PMID:7657827

  13. In vitro and in vivo changes in human complement caused by silage.

    PubMed Central

    Olenchock, S A; May, J J; Pratt, D S; Lewis, D M; Mull, J C; Stallones, L

    1986-01-01

    Aqueous extracts of silage samples from four farms in up-state New York were reacted in vitro with normal human serum. Hemolytic levels of complement component C3 were consumed in a dose-dependent fashion, and the four extracts differed in their relative activity rankings. Studies with chelated serum indicate that the alternative complement pathway is involved in the activation, and the active fragment C3b was demonstrated. Serum levels of hemolytic C3 and C4 in vivo were quantified before and after farmers performed their normal silo unloading operations. Although the study groups were small, suggestive evidence of in vivo complement consumption was found. IgE-related allergy did not appear to be of significance to the study groups. Complement activation may be an initiator of or contributor to adverse reactions in farmers who are exposed to airborne silage dusts. Images FIGURE 2. FIGURE 3. PMID:3709488

  14. T cell deficiency in patients with autoimmune hemolytic anemia ('warm type').

    PubMed

    Krüger, J; Rahman, A; Mogk, K U; Mueller-Eckhardt, C

    1976-01-01

    19 patients with chronic 'warm type' autoimmune hemolytic anemia were studied for abnormalities of cellular immune reactions. Evidence was obtained for a reduction of rosette-forming cells (RFC). Lymphocytotoxic antibodies were present in only 8 patients and correlated, with only one exception, with a reduced number of RFC. No significant deviation from normal ranges of the three major immunoglobulin classes in the patients' sera were found. C3 and C4 complement components were also, with one exception, within normal limits. In 18 of 19 patients no apparent association existed between the type or the amount of autoantibodies and/or complement components fixed on red cells and the levels of the respective immunoglobulins or complement in the sera. PMID:1084624

  15. Collagen-binding Microbial Surface Components Recognizing Adhesive Matrix Molecule (MSCRAMM) of Gram-positive Bacteria Inhibit Complement Activation via the Classical Pathway*

    PubMed Central

    Kang, Mingsong; Ko, Ya-Ping; Liang, Xiaowen; Ross, Caná L.; Liu, Qing; Murray, Barbara E.; Höök, Magnus

    2013-01-01

    Members of a family of collagen-binding microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) from Gram-positive bacteria are established virulence factors in several infectious diseases models. Here, we report that these adhesins also can bind C1q and act as inhibitors of the classical complement pathway. Molecular analyses of Cna from Staphylococcus aureus suggested that this prototype MSCRAMM bound to the collagenous domain of C1q and interfered with the interactions of C1r with C1q. As a result, C1r2C1s2 was displaced from C1q, and the C1 complex was deactivated. This novel function of the Cna-like MSCRAMMs represents a potential immune evasion strategy that could be used by numerous Gram-positive pathogens. PMID:23720782

  16. Von Willebrand factor regulates complement on endothelial cells.

    PubMed

    Noone, Damien G; Riedl, Magdalena; Pluthero, Fred G; Bowman, Mackenzie L; Liszewski, M Kathryn; Lu, Lily; Quan, Yi; Balgobin, Steve; Schneppenheim, Reinhard; Schneppenheim, Sonja; Budde, Ulrich; James, Paula; Atkinson, John P; Palaniyar, Nades; Kahr, Walter H A; Licht, Christoph

    2016-07-01

    Atypical hemolytic uremic syndrome and thrombotic thrombocytopenic purpura have traditionally been considered separate entities. Defects in the regulation of the complement alternative pathway occur in atypical hemolytic uremic syndrome, and defects in the cleavage of von Willebrand factor (VWF)-multimers arise in thrombotic thrombocytopenic purpura. However, recent studies suggest that both entities are related as defects in the disease-causing pathways overlap or show functional interactions. Here we investigate the possible functional link of VWF-multimers and the complement system on endothelial cells. Blood outgrowth endothelial cells (BOECs) were obtained from 3 healthy individuals and 2 patients with Type 3 von Willebrand disease lacking VWF. Cells were exposed to a standardized complement challenge via the combination of classical and alternative pathway activation and 50% normal human serum resulting in complement fixation to the endothelial surface. Under these conditions we found the expected release of VWF-multimers causing platelet adhesion onto BOECs from healthy individuals. Importantly, in BOECs derived from patients with von Willebrand disease complement C3c deposition and cytotoxicity were more pronounced than on BOECs derived from normal individuals. This is of particular importance as primary glomerular endothelial cells display a heterogeneous expression pattern of VWF with overall reduced VWF abundance. Thus, our results support a mechanistic link between VWF-multimers and the complement system. However, our findings also identify VWF as a new complement regulator on vascular endothelial cells and suggest that VWF has a protective effect on endothelial cells and complement-mediated injury. PMID:27236750

  17. Efficacy and safety of eculizumab in atypical hemolytic uremic syndrome from 2-year extensions of phase 2 studies

    PubMed Central

    Licht, Christoph; Greenbaum, Larry A; Muus, Petra; Babu, Sunil; Bedrosian, Camille L; Cohen, David J; Delmas, Yahsou; Douglas, Kenneth; Furman, Richard R; Gaber, Osama A; Goodship, Timothy; Herthelius, Maria; Hourmant, Maryvonne; Legendre, Christophe M; Remuzzi, Giuseppe; Sheerin, Neil; Trivelli, Antonella; Loirat, Chantal

    2015-01-01

    Atypical hemolytic uremic syndrome (aHUS) is a rare, possibly life-threatening disease characterized by platelet activation, hemolysis and thrombotic microangiopathy (TMA) leading to renal and other end-organ damage. We originally conducted two phase 2 studies (26 weeks and 1 year) evaluating eculizumab, a terminal complement inhibitor, in patients with progressing TMA (trial 1) and those with long duration of aHUS and chronic kidney disease (trial 2). The current analysis assessed outcomes after 2 years (median eculizumab exposure 100 and 114 weeks, respectively). At all scheduled time points, eculizumab inhibited terminal complement activity. In trial 1 with 17 patients, the platelet count was significantly improved from baseline, and hematologic normalization was achieved in 13 patients at week 26, and in 15 patients at both 1 and 2 years. The estimated glomerular filtration rate (eGFR) was significantly improved compared with baseline and year 1. In trial 2 with 20 patients, TMA event-free status was achieved by 16 patients at week 26, 17 patients at year 1, and 19 patients at year 2. Criteria for hematologic normalization were met by 18 patients at each time point. Improvement of 15 ml/min per 1.73 m2 or more in eGFR was achieved by 1 patient at week 26, 3 patients at 1 year, and 8 patients at 2 years. The mean change in eGFR was not significant compared with baseline, week 26, or year 1. Eculizumab was well tolerated, with no new safety concerns or meningococcal infections. Thus, a 2-year analysis found that the earlier clinical benefits achieved by eculizumab treatment of aHUS were maintained at 2 years of follow-up. PMID:25651368

  18. Clinical Application of Immunofluorescence I. Grouping β-Hemolytic Streptococci

    PubMed Central

    Smith, Thomas B.

    1965-01-01

    Smith, Thomas B. (Armed Forces Institute of Pathology, Washington, D.C.). Clinical application of immunofluorescence. I. Grouping β-hemolytic streptococci. J. Bacteriol. 89:198–204. 1965.—Procedures are described for the production of antistreptococcal serum in rabbits and for the preparation of group-specific conjugates for Lancefield groups A, C, and G. A modification of the conventional technique of absorption and inhibition to prevent cross-reactions with common antigens was used with excellent results. In addition, a promising new approach to eliminating cross-reactions of group A conjugate with antigens of groups C and G by dilution with group A-variant antiserum was tested. A complete method is introduced that enables the clinical laboratory to report whether group A streptococci are present in a given throat culture well within 24 hr after the physician collects the sample. Images PMID:14255663

  19. No association between dysplasminogenemia with p.Ala620Thr mutation and atypical hemolytic uremic syndrome.

    PubMed

    Miyata, Toshiyuki; Uchida, Yumiko; Yoshida, Yoko; Kato, Hideki; Matsumoto, Masanori; Kokame, Koichi; Fujimura, Yoshihiro; Nangaku, Masaomi

    2016-08-01

    Atypical hemolytic uremic syndrome (aHUS), a form of thrombotic microangiopathy, is caused by the uncontrolled activation of the alternative pathway of complement on the cell surface that leads to microangiopathic hemolytic anemia, thrombocytopenia, and renal failure. A recent genetic analysis of aHUS patients identified deleterious mutations not only in complement or complement regulatory genes but also in the plasminogen gene, suggesting that subnormal plasminogen activity may be related to the degradation of thrombi in aHUS. Dysplasminogenemia, which is caused by a genetic variant in the plasminogen gene, PLG:p.Ala620Thr, is commonly observed in the northeast Asian populations, including Japanese. To examine the association between dysplasminogenemia and aHUS, we genotyped PLG:p.Ala620Thr in 103 Japanese patients with aHUS. We identified five aHUS patients with PLG:p.Ala620Thr; the minor allele frequency (MAF) was thus 0.024. The MAF in the patient group was not significantly different from those obtained from a general Japanese population (MAF = 0.020) and the Japanese genetic variation HGDV database (MAF = 0.021) (P = 0.62 and 0.61, respectively). We concluded that, although carriers with PLG:p.Ala620Thr show low plasminogen activity, this is not a predisposing variant for aHUS and that individuals of dysplasminogenemia are not at significantly increased risk of aHUS. PMID:27194432

  20. Peroxisome Proliferator-activated Receptor α Positively Regulates Complement C3 Expression but Inhibits Tumor Necrosis Factor α-mediated Activation of C3 Gene in Mammalian Hepatic-derived Cells*

    PubMed Central

    Mogilenko, Denis A.; Kudriavtsev, Igor V.; Shavva, Vladimir S.; Dizhe, Ella B.; Vilenskaya, Ekaterina G.; Efremov, Alexander M.; Perevozchikov, Andrej P.; Orlov, Sergey V.

    2013-01-01

    Complement C3 is a pivotal component of three cascades of complement activation. The liver is the main source of C3 in circulation and expression and secretion of C3 by hepatocytes is increased during acute inflammation. However, the mechanism of the regulation of the C3 gene in hepatocytes is not well elucidated. We showed that the C3 gene is the direct target for peroxisome proliferator-activated receptor α (PPARα) in human hepatoma HepG2 cells and mouse liver. Using PPARα siRNA and synthetic PPARα agonist WY-14643 and antagonist MK886 we showed that activation of PPARα results in up-regulation of C3 gene expression and protein secretion by HepG2 cells. The PPAR response element (PPRE), which is able to bind PPARα in vitro and in vivo, was found in the human C3 promoter. PPRE is conserved between human and mouse, and WY-14643 stimulates mouse C3 expression in the liver. TNFα increases C3 gene via NF-κB and, to a lesser extent, MEK1/2 signaling pathways, whereas TNFα-mediated stimulation of C3 protein secretion depends on activation of MEK1/2, p38, and JNK in HepG2 cells. Activation of PPARα abolishes TNFα-mediated up-regulation of C3 gene expression and protein secretion due to interference with NF-κB via PPRE-dependent mechanism in HepG2 cells. TNFα decreases PPARα protein content via NF-κB and MEK1/2 signaling pathways and inhibits PPARα binding with the human C3 promoter in HepG2 cells. These results suggest novel mechanism controlling C3 expression in hepatocytes during acute phase inflammation and demonstrate a crosstalk between PPARα and TNFα in the regulation of complement system. PMID:23168409

  1. [Clinical aspects of endotheliotropic (hemolytic) nephroangiopathy].

    PubMed

    Renner, E; Cohen, S

    1989-01-01

    Clinical syndromes as hemolytic-uremic-syndrome, thrombotic-thrombocytopenic-pupura and primary-malignant-hypertension not only present multiple clinical but also etiological and pathogenetical common characteristics. Thoenes and John developed in 1980 the unifying concept of endotheliotropic (hemolytic) nephroangiopathy for these diseases which are characterised by pathologic interaction between damaged endothelial cells and erythrocytes. This concept was increasingly discussed and accepted in the literature during the course of the last years. We describe the clinical manifestation of the subgroupes which were defined by Thoenes and John according to the vascular pattern of pathomorphologic intrarenal lesions. It can be shown that the classification based on pathomorphologic findings is very useful for the differentialdiagnostic characterisation and the prognostic evaluation in a given single case. PMID:2482603

  2. An international consensus approach to the management of atypical hemolytic uremic syndrome in children.

    PubMed

    Loirat, Chantal; Fakhouri, Fadi; Ariceta, Gema; Besbas, Nesrin; Bitzan, Martin; Bjerre, Anna; Coppo, Rosanna; Emma, Francesco; Johnson, Sally; Karpman, Diana; Landau, Daniel; Langman, Craig B; Lapeyraque, Anne-Laure; Licht, Christoph; Nester, Carla; Pecoraro, Carmine; Riedl, Magdalena; van de Kar, Nicole C A J; Van de Walle, Johan; Vivarelli, Marina; Frémeaux-Bacchi, Véronique

    2016-01-01

    Atypical hemolytic uremic syndrome (aHUS) emerged during the last decade as a disease largely of complement dysregulation. This advance facilitated the development of novel, rational treatment options targeting terminal complement activation, e.g., using an anti-C5 antibody (eculizumab). We review treatment and patient management issues related to this therapeutic approach. We present consensus clinical practice recommendations generated by HUS International, an international expert group of clinicians and basic scientists with a focused interest in HUS. We aim to address the following questions of high relevance to daily clinical practice: Which complement investigations should be done and when? What is the importance of anti-factor H antibody detection? Who should be treated with eculizumab? Is plasma exchange therapy still needed? When should eculizumab therapy be initiated? How and when should complement blockade be monitored? Can the approved treatment schedule be modified? What approach should be taken to kidney and/or combined liver-kidney transplantation? How should we limit the risk of meningococcal infection under complement blockade therapy? A pressing question today regards the treatment duration. We discuss the need for prospective studies to establish evidence-based criteria for the continuation or cessation of anticomplement therapy in patients with and without identified complement mutations. PMID:25859752

  3. ORF2 protein of porcine circovirus type 2 promotes phagocytic activity of porcine macrophages by inhibiting proteasomal degradation of complement component 1, q subcomponent binding protein (C1QBP) through physical interaction.

    PubMed

    Choi, Chang-Yong; Oh, Hae-Na; Lee, Suk Jun; Chun, Taehoon

    2015-11-01

    Defining how each ORF of porcine circovirus type 2 (PCV2) manipulates the host immune system may be helpful to understand the disease progression of post-weaning multisystemic wasting syndrome. In this study, we demonstrated a direct interaction between the PCV2 ORF2 and complement component 1, q subcomponent binding protein (C1QBP) within the cytoplasm of host macrophages. The physical interaction between PCV2 ORF2 and C1QBP inhibited ubiquitin-mediated proteasomal degradation of C1QBP in macrophages. Increased stability of C1QBP by the interaction with PCV2 ORF2 further enhanced the phagocytic activity of porcine macrophages through the phosphoinositol 3-kinase signalling pathway. This may explain the molecular basis of how PCV2 ORF2 enhances the phagocytic activity of host macrophages. PMID:26361775

  4. Characterization of group A Streptococcus strains recovered from Mexican children with pharyngitis by automated DNA sequencing of virulence-related genes: unexpectedly large variation in the gene (sic) encoding a complement-inhibiting protein.

    PubMed

    Mejia, L M; Stockbauer, K E; Pan, X; Cravioto, A; Musser, J M

    1997-12-01

    Sequence variation was studied in several target genes in 54 strains of group A Streptococcus (GAS) cultured from children with pharyngitis in Mexico City. Although 16 distinct emm alleles were identified, only 4 had not been previously described. Virtually all bacteria (31 of 33 [94%] with the streptococcal pyrogenic exotoxin gene (speA) had emm1-related, emm3, or emm6 alleles. The gene (sic) encoding an extracellular GAS protein that inhibits complement function was unusually variable among isolates with the emm1 family of alleles, with a total of seven variants identified. The data suggest that many GAS strains infecting Mexican children are genetically similar to organisms commonly encountered in the United States and western Europe. Sequence variation in the sic gene is useful for rapid differentiation among GAS isolates with the emm1 family of alleles. PMID:9399523

  5. Characterization of group A Streptococcus strains recovered from Mexican children with pharyngitis by automated DNA sequencing of virulence-related genes: unexpectedly large variation in the gene (sic) encoding a complement-inhibiting protein.

    PubMed Central

    Mejia, L M; Stockbauer, K E; Pan, X; Cravioto, A; Musser, J M

    1997-01-01

    Sequence variation was studied in several target genes in 54 strains of group A Streptococcus (GAS) cultured from children with pharyngitis in Mexico City. Although 16 distinct emm alleles were identified, only 4 had not been previously described. Virtually all bacteria (31 of 33 [94%] with the streptococcal pyrogenic exotoxin gene (speA) had emm1-related, emm3, or emm6 alleles. The gene (sic) encoding an extracellular GAS protein that inhibits complement function was unusually variable among isolates with the emm1 family of alleles, with a total of seven variants identified. The data suggest that many GAS strains infecting Mexican children are genetically similar to organisms commonly encountered in the United States and western Europe. Sequence variation in the sic gene is useful for rapid differentiation among GAS isolates with the emm1 family of alleles. PMID:9399523

  6. Streptolysin S of Streptococcus anginosus exhibits broad-range hemolytic activity.

    PubMed

    Asam, Daniela; Mauerer, Stefanie; Spellerberg, Barbara

    2015-04-01

    Streptococcus anginosus is a commensal of mucous membranes and an emerging human pathogen. Some strains, including the type strain, display a prominent β-hemolytic phenotype. A gene cluster (sag), encoding a variant of streptolysin S (SLS) has recently been identified as the genetic background for β-hemolysin production in S. anginosus. In this study, we further characterized the hemolytic and cytolytic activity of the S. anginosus hemolysin in comparison with other streptococcal hemolysins. The results indicate that SLS of S. anginosus is a broad-range hemolysin able to lyse erythrocytes of different species, including horse, bovine, rabbit and even chicken. The hemolytic activity is temperature dependent, and a down-regulation of the hemolysin expression is induced in the presence of high glucose levels. Survival assays indicate that in contrast to other streptococcal species, S. anginosus does not require SLS for survival in the presence of human granulocytes. Cross-complementation studies using the sagB and sagD genes of Streptococcus pyogenes and Streptococcus dysgalactiae subsp. equisimilis demonstrated functional similarities to the S. anginosus SLS. Nevertheless, distinct differences to other streptolysin S variants were noted and provide further insights into the molecular mechanisms of SLS pathogen host interactions. PMID:25381594

  7. Atypical Hemolytic-Uremic Syndrome: A Case Report and Literature Review

    PubMed Central

    Rafiq, Arsalan; Tariq, Hassan; Abbas, Naeem; Shenoy, Roopalekha

    2015-01-01

    Patient: Female, 59 Final Diagnosis: Atyipcal hemolytic uremic syndrome Symptoms: Delirium • headache Medication: — Clinical Procedure: — Specialty: Hematology Objective: Rare disease Background: Atypical hemolytic uremic syndrome (aHUS) is a rare disease characterized by hemolysis, thrombocytopenia, and renal dysfunction. It is a disease related to genetic mutations in the alternative complement pathway and has a distinct pathophysiology but is difficult to differentiate from other thrombotic microangiopathies. Case Report: We present a case of a 59-year-old female patient who presented with accelerated hypertension, acute renal failure, hemolysis, and encephalopathy. She was managed with antihypertensive medication, but her encephalopathy did not improve. Evaluation resulted in our impression of the disease being atypical hemolytic-uremic syndrome. The patient continued to be managed with good blood pressure control and later was started on eculizumab, but evaluation of response to therapy was hindered by the patient’s non-compliance with therapy and follow-up appointments. Conclusions: We have a very limited understanding of the genetics and epidemiology of atypical HUS, and the overlapping clinical features sometimes delay diagnosis and initiation of appropriate treatment of this rare disease. PMID:25708146

  8. Role of sph2 Gene Regulation in Hemolytic and Sphingomyelinase Activities Produced by Leptospira interrogans

    PubMed Central

    Narayanavari, Suneel A.; Lourdault, Kristel; Sritharan, Manjula; Haake, David A.; Matsunaga, James

    2015-01-01

    . Complementation of the mutation with the sph2 gene partially restored production of hemolytic and sphingomyelinase activities. These results indicate that the sph2 gene product contributes to the hemolytic and sphingomyelinase activities secreted by L. interrogans and most likely dominates those functions under the culture condition tested. PMID:26274394

  9. Management of hemolytic-uremic syndrome in children

    PubMed Central

    Grisaru, Silviu

    2014-01-01

    Acute renal failure associated with a fulminant, life-threatening systemic disease is rare in previously healthy young children; however, when it occurs, the most common cause is hemolytic-uremic syndrome (HUS). In most cases (90%), this abrupt and devastating illness is a result of ingestion of food or drink contaminated with pathogens that produce very potent toxins. Currently, there are no proven treatment options that can directly inactivate the toxin or effectively interfere with the cascade of destructive events triggered by the toxin once it gains access to the bloodstream and binds its receptor. However, HUS is self-limited, and effective supportive management during the acute phase is proven to be a life saver for children affected by HUS. A minority of childhood HUS cases, approximately 5%, are caused by various genetic mutations causing uncontrolled activation of the complement system. These children, who used to have a poor prognosis leading to end-stage renal disease, now have access to exciting new treatment options that can preserve kidney function and avoid disease recurrences. This review provides a summary of the current knowledge on the epidemiology, pathophysiology, and clinical presentation of childhood HUS, focusing on a practical approach to best management measures. PMID:24966691

  10. Modified Ham test for atypical hemolytic uremic syndrome

    PubMed Central

    Gavriilaki, Eleni; Yuan, Xuan; Ye, Zhaohui; Ambinder, Alexander J.; Shanbhag, Satish P.; Streiff, Michael B.; Kickler, Thomas S.; Moliterno, Alison R.; Sperati, C. John

    2015-01-01

    Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy (TMA) characterized by excessive activation of the alternative pathway of complement (APC). Atypical HUS is frequently a diagnosis of exclusion. Differentiating aHUS from other TMAs, especially thrombotic thrombocytopenic purpura (TTP), is difficult due to overlapping clinical manifestations. We sought to develop a novel assay to distinguish aHUS from other TMAs based on the hypothesis that paroxysmal nocturnal hemoglobinuria cells are more sensitive to APC-activated serum due to deficiency of glycosylphosphatidylinositol- anchored complement regulatory proteins (GPI-AP). Here, we demonstrate that phosphatidylinositol-specific phospholipase C–treated EA.hy926 cells and PIGA-mutant TF-1 cells are more susceptible to serum from aHUS patients than parental EA.hy926 and TF-1 cells. We next studied 31 samples from 25 patients with TMAs, including 9 with aHUS and 12 with TTP. Increased C5b-9 deposition was evident by confocal microscopy and flow cytometry on GPI-AP–deficient cells incubated with aHUS serum compared with heat-inactivated control, TTP, and normal serum. Differences in cell viability were observed in biochemically GPI-AP–deficient cells and were further increased in PIGA-deficient cells. Serum from patients with aHUS resulted in a significant increase of nonviable PIGA-deficient TF-1 cells compared with serum from healthy controls (P < .001) and other TMAs (P < .001). The cell viability assay showed high reproducibility, sensitivity, and specificity in detecting aHUS. In conclusion, we developed a simple, rapid, and serum-based assay that helps to differentiate aHUS from other TMAs. PMID:25862562

  11. Complement and Viral Pathogenesis

    PubMed Central

    Stoermer, Kristina A.; Morrison, Thomas E.

    2011-01-01

    The complement system functions as an immune surveillance system that rapidly responds to infection. Activation of the complement system by specific recognition pathways triggers a protease cascade, generating cleavage products that function to eliminate pathogens, regulate inflammatory responses, and shape adaptive immune responses. However, when dysregulated, these powerful functions can become destructive and the complement system has been implicated as a pathogenic effector in numerous diseases, including infectious diseases. This review highlights recent discoveries that have identified critical roles for the complement system in the pathogenesis of viral infection. PMID:21292294

  12. Genetics Home Reference: atypical hemolytic-uremic syndrome

    MedlinePlus

    ... uremic syndrome Additional NIH Resources (3 links) National Heart, Lung, and Blood Institute: Hemolytic Anemia National Heart, Lung, and Blood Institute: Thrombocytopenia National Institute of Diabetes ...

  13. Novel Twin Streptolysin S-Like Peptides Encoded in the sag Operon Homologue of Beta-Hemolytic Streptococcus anginosus

    PubMed Central

    Tabata, Atsushi; Nakano, Kota; Ohkura, Kazuto; Tomoyasu, Toshifumi; Kikuchi, Ken; Whiley, Robert A.

    2013-01-01

    Streptococcus anginosus is a member of the anginosus group streptococci, which form part of the normal human oral flora. In contrast to the pyogenic group streptococci, our knowledge of the virulence factors of the anginosus group streptococci, including S. anginosus, is not sufficient to allow a clear understanding of the basis of their pathogenicity. Generally, hemolysins are thought to be important virulence factors in streptococcal infections. In the present study, a sag operon homologue was shown to be responsible for beta-hemolysis in S. anginosus strains by random gene knockout. Interestingly, contrary to pyogenic group streptococci, beta-hemolytic S. anginosus was shown to have two tandem sagA homologues, encoding streptolysin S (SLS)-like peptides, in the sag operon homologue. Gene deletion and complementation experiments revealed that both genes were functional, and these SLS-like peptides were essential for beta-hemolysis in beta-hemolytic S. anginosus. Furthermore, the amino acid sequence of these SLS-like peptides differed from that of the typical SLS of S. pyogenes, especially in their propeptide domain, and an amino acid residue indicated to be important for the cytolytic activity of SLS in S. pyogenes was deleted in both S. anginosus homologues. These data suggest that SLS-like peptides encoded by two sagA homologues in beta-hemolytic S. anginosus may be potential virulence factors with a different structure essential for hemolytic activity and/or the maturation process compared to the typical SLS present in pyogenic group streptococci. PMID:23292771

  14. Medicago truncatula CYP716A12 Is a Multifunctional Oxidase Involved in the Biosynthesis of Hemolytic Saponins[W

    PubMed Central

    Carelli, Maria; Biazzi, Elisa; Panara, Francesco; Tava, Aldo; Scaramelli, Laura; Porceddu, Andrea; Graham, Neil; Odoardi, Miriam; Piano, Efisio; Arcioni, Sergio; May, Sean; Scotti, Carla; Calderini, Ornella

    2011-01-01

    Saponins, a group of glycosidic compounds present in several plant species, have aglycone moieties that are formed using triterpenoid or steroidal skeletons. In spite of their importance as antimicrobial compounds and their possible benefits for human health, knowledge of the genetic control of saponin biosynthesis is still poorly understood. In the Medicago genus, the hemolytic activity of saponins is related to the nature of their aglycone moieties. We have identified a cytochrome P450 gene (CYP716A12) involved in saponin synthesis in Medicago truncatula using a combined genetic and biochemical approach. Genetic loss-of-function analysis and complementation studies showed that CYP716A12 is responsible for an early step in the saponin biosynthetic pathway. Mutants in CYP716A12 were unable to produce hemolytic saponins and only synthetized soyasaponins, and were thus named lacking hemolytic activity (lha). In vitro enzymatic activity assays indicate that CYP716A12 catalyzes the oxidation of β-amyrin and erythrodiol at the C-28 position, yielding oleanolic acid. Transcriptome changes in the lha mutant showed a modulation in the main steps of triterpenic saponin biosynthetic pathway: squalene cyclization, β-amyrin oxidation, and glycosylation. The analysis of CYP716A12 expression in planta is reported together with the sapogenin content in different tissues and stages. This article provides evidence for CYP716A12 being a key gene in hemolytic saponin biosynthesis. PMID:21821776

  15. Hemolytic anemia in two patients with glioblastoma multiforme: A possible interaction between vorinostat and dapsone.

    PubMed

    Lewis, Jennifer A; Petty, William J; Harmon, Michele; Peacock, James E; Valente, Kari; Owen, John; Pirmohamed, Munir; Lesser, Glenn J

    2015-06-01

    Patients undergoing treatment for glioblastoma multiforme are routinely placed on prophylactic treatment for Pneumocystis jirovecii pneumonia because of significant therapy-induced lymphopenia. In patients with sulfa allergies, dapsone prophylaxis is often used due to its efficacy, long half-life, cost effectiveness, and general safety at low doses. However, dapsone may uncommonly induce a hemolytic anemia, particularly in patients deficient of glucose-6-phosphate dehydrogenase. This hemolysis is thought to be a result of oxidative stress on red blood cells induced by dapsone metabolites which produce reactive oxygen species that disrupt the red blood cell membrane and promote splenic sequestration. A single case report of dapsone-induced hemolytic anemia in a patient with glioblastoma multiforme has been reported. We present two patients with glioblastoma multiforme who developed severe hemolytic anemia shortly after initiating therapy with vorinostat, a pan-active histone deacetylase inhibitor, while on prophylactic dapsone. There are several potential mechanisms by which histone deacetylase inhibition may alter dapsone metabolism including changes in hepatic acetylation or N-glucuronidation leading to an increase in the bioavailability of dapsone's hematotoxic metabolites. In addition, vorinostat may lead to increased hemolysis through inhibition of heat shock protein-90, a chaperone protein that maintains the integrity of the red blood cell membrane cytoskeleton. The potential interaction between dapsone and vorinostat may have important clinical implications as more than 10 clinical trials evaluating drug combinations with vorinostat in patients with malignant glioma are either ongoing or planned in North America. PMID:24576944

  16. Cytotoxicity for porcine islet cells by complement of six animal species.

    PubMed

    Itakura, Shin; Kato, Hisamune; Wang, Pi-Chao; Matsunaga, Atsuko; Jitsukawa, Tomofumi; Edamura, Kazuya; Ohgawara, Hisako; Mochizuki, Manabu; Nishimura, Ryohei; Sasaki, Nobuo

    2003-10-01

    Complement-mediated cytotoxicity for porcine islet cells (PICs) was evaluated using sera of six animal species. Then soluble complement receptor type-1 (sCR1) as an anti-complement agent was added to those sera, and the changes in 50% hemolytic unit of complement serum (CH50) and cytotoxic effect of those sera on PICs were examined. All the sera except for that of pig showed cytotoxicity. However, the extent of toxicity was considerably different between species. In the rat and human serum, sCR1 significantly reduced CH50 and cytotoxicity, however in the dog serum, sCR1 had no suppressive effects. These results may suggest that complement contribute to humoral cytotoxicity for PICs as a main factor, and the compatibility of complement with PICs differs between animal species. PMID:14600349

  17. Clinical Applications of Hemolytic Markers in the Differential Diagnosis and Management of Hemolytic Anemia

    PubMed Central

    Barcellini, W.; Fattizzo, B.

    2015-01-01

    Several hemolytic markers are available to guide the differential diagnosis and to monitor treatment of hemolytic conditions. They include increased reticulocytes, an indicator of marrow compensatory response, elevated lactate dehydrogenase, a marker of intravascular hemolysis, reduced haptoglobin, and unconjugated hyperbilirubinemia. The direct antiglobulin test is the cornerstone of autoimmune forms, and blood smear examination is fundamental in the diagnosis of congenital membrane defects and thrombotic microangiopathies. Marked increase of lactate dehydrogenase and hemosiderinuria are typical of intravascular hemolysis, as observed in paroxysmal nocturnal hemoglobinuria, and hyperferritinemia is associated with chronic hemolysis. Prosthetic valve replacement and stenting are also associated with intravascular and chronic hemolysis. Compensatory reticulocytosis may be inadequate/absent in case of marrow involvement, iron/vitamin deficiency, infections, or autoimmune reaction against bone marrow-precursors. Reticulocytopenia occurs in 20–40% of autoimmune hemolytic anemia cases and is a poor prognostic factor. Increased reticulocytes, lactate dehydrogenase, and bilirubin, as well as reduced haptoglobin, are observed in conditions other than hemolysis that may confound the clinical picture. Hemoglobin defines the clinical severity of hemolysis, and thrombocytopenia suggests a possible thrombotic microangiopathy or Evans' syndrome. A comprehensive clinical and laboratory evaluation is advisable for a correct diagnostic and therapeutic workup of the different hemolytic conditions. PMID:26819490

  18. Targeting complement in therapy.

    PubMed

    Kirschfink, M

    2001-04-01

    With increasing evidence that complement activation significantly contributes to the pathogenesis of a large number of inflammatory diseases, strategies that interfere with its deleterious action have become a major focus in pharmacological research. Endogenous soluble complement inhibitors (C1 inhibitor, recombinant soluble complement receptor 1, antibodies) blocking key proteins of the cascade reaction, neutralizing the action of the complement-derived anaphylatoxin C5a, or interfering with complement receptor 3 (CR3, CD18/11b)-mediated adhesion of inflammatory cells to the vascular endothelium have successfully been tested in various animal models over the past years. Promising results consequently led to clinical trials. Furthermore, incorporation of membrane-bound complement regulators (decay-accelerating factor (CD55), membrane co-factor protein (CD46), CD59) in transgenic animals has provided a major step forward in protecting xenografts from hyperacute rejection. At the same time, the poor contribution of complement to the antitumor response, which is caused by multiple resistance mechanisms that hamper the efficacy of antibody-based tumor therapy, is increasingly recognized and requires pharmacologic intervention. First attempts have now been made to interfere with the resistance mechanisms, thereby improving complement-mediated tumor cell destruction. PMID:11414360

  19. Eculizumab in Typical Hemolytic Uremic Syndrome (HUS) With Neurological Involvement

    PubMed Central

    Pape, Lars; Hartmann, Hans; Bange, Franz Christoph; Suerbaum, Sebastian; Bueltmann, Eva; Ahlenstiel-Grunow, Thurid

    2015-01-01

    Abstract In typical hemolytic uremic syndrome (HUS) approximately 25% of patients show central nervous system (CNS) involvement often leading to serious long-term disabilities. We used the C5-complement inhibitor Eculizumab as rescue therapy. From 2011 to 2014, 11 children (median age 22 months, range 11–175) with enterohemorrhagic Escherichia coli-positive HUS requiring dialysis who had seizures (11/11) and/or were in a stupor or coma (10/11) were treated with Eculizumab. Two patients enrolled on the Safety and Efficacy Study of Eculizumab in Shiga-Toxin Producing E coli Hemolytic-Uremic Syndrome (STEC-HUS) each received 6 doses of Eculizumab, 3 patients 2 doses, and 6 patients 1 dose. Laboratory diagnostics of blood samples and magnetic resonance imaging (MRI) were performed as per center practice. Data were analyzed retrospectively. Cranial MRI was abnormal in 8 of 10 patients with findings in the basal ganglia and/or white matter. A 2-year-old boy with severe cardiac involvement and status epilepticus needed repeated cardio-pulmonary resuscitation and extracorporeal membrane oxygenation. He died 8 days after start of Eculizumab treatment. Two patients with hemorrhagic colitis and repeated seizures required artificial ventilation for 6 and 16 days, respectively. At the time of discharge, 1 patient showed severe neurological impairment and 1 mild neurological impairment. The 8 surviving patients experienced no further seizures after the first dose of Eculizumab. Three patients showed mild neurological impairment at discharge, whilst the remaining 5 showed no impairment. The platelets normalized 4 days (median) after the first dose of Eculizumab (range 0–20 days). The mean duration of dialysis after the first dose of Eculizumab was 14.1 ± 6.1 days. In children with typical HUS and CNS involvement early use of Eculizumab appears to improve neurological outcome. In severe HUS cases which progress rapidly with multiple organ involvement, late treatment with

  20. The Clinical Pictures of Autoimmune Hemolytic Anemia.

    PubMed

    Packman, Charles H

    2015-09-01

    Autoimmune hemolytic anemia is characterized by shortened red blood cell survival and a positive Coombs test. The responsible autoantibodies may be either warm reactive or cold reactive. The rate of hemolysis and the severity of the anemia may vary from mild to severe and life-threatening. Diagnosis is made in the laboratory by the findings of anemia, reticulocytosis, a positive Coombs test, and specific serologic tests. The prognosis is generally good but renal failure and death sometimes occur, especially in cases mediated by drugs. PMID:26696800

  1. The Clinical Pictures of Autoimmune Hemolytic Anemia

    PubMed Central

    Packman, Charles H.

    2015-01-01

    Summary Autoimmune hemolytic anemia is characterized by shortened red blood cell survival and a positive Coombs test. The responsible autoantibodies may be either warm reactive or cold reactive. The rate of hemolysis and the severity of the anemia may vary from mild to severe and life-threatening. Diagnosis is made in the laboratory by the findings of anemia, reticulocytosis, a positive Coombs test, and specific serologic tests. The prognosis is generally good but renal failure and death sometimes occur, especially in cases mediated by drugs. PMID:26696800

  2. Comparison of nephelometric and hemolytic techniques for determination of antistreptolysin O antibodies.

    PubMed

    Pacifico, L; Mancuso, G; Properzi, E; Ravagnan, G; Pasquino, A M; Chiesa, C

    1995-04-01

    The sensitivity of a newly devised nephelometric method for determining antistreptolysin O antibodies was compared with the hemolytic inhibition assay. Three hundred-thirty single serum samples from children with and without evidence of group A streptococcal infection were analyzed by the two techniques. The nephelometric method results correlated well with those of the reference test (concordance: r = 0.88). Furthermore, 134 pairs of acute and convalescent phase sera from patients with culture-proven GAS infection and 50 pairs from children who served as control subjects were examined. The nephelometric assay was more sensitive in detecting significant ASO antibody rises than the hemolytic assay. The automated nephelometric method appears to be a much simpler and sensitive procedure for testing ASO antibodies. PMID:7726133

  3. TNF Regulates Essential Alternative Complement Pathway Components and Impairs Activation of Protein C in Human Glomerular Endothelial Cells.

    PubMed

    Sartain, Sarah E; Turner, Nancy A; Moake, Joel L

    2016-01-15

    Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy with severe renal injury secondary to an overactive alternative complement pathway (AP). aHUS episodes are often initiated or recur during inflammation. We investigated gene expression of the surface complement regulatory proteins (CD55, CD59, CD46, and CD141 [thrombomodulin]) and AP components in human glomerular microvascular endothelial cells (GMVECs) and in HUVECs, a frequently used investigational model of endothelial cells. Surface complement regulatory proteins were also quantified by flow cytometry. All experiments were done with and without exposure to IL-1β or TNF. Without cytokine stimulation, we found that GMVECs had greater AP activation than did HUVECs. With TNF stimulation, THBD gene expression and corresponding CD141 surface presence in HUVECs and GMVECs were reduced, and gene expression of complement components C3 (C3) and factor B (CFB) was increased. Consequently, AP activation, measured by Ba production, was increased, and conversion of protein C (PC) to activated PC by CD141-bound thrombin was decreased, in GMVECs and HUVECs exposed to TNF. IL-1β had similar, albeit lesser, effects on HUVEC gene expression, and it only slightly affected GMVEC gene expression. To our knowledge, this is the first detailed study of the expression/display of AP components and surface regulatory proteins in GMVECs with and without cytokine stimulation. In aHUS patients with an underlying overactive AP, additional stimulation of the AP and inhibition of activated PC-mediated anticoagulation in GMVECs by the inflammatory cytokine TNF are likely to provoke episodes of renal failure. PMID:26673143

  4. Legionella pneumophila lipopolysaccharide activates the classical complement pathway.

    PubMed Central

    Mintz, C S; Schultz, D R; Arnold, P I; Johnson, W

    1992-01-01

    Legionella pneumophila is a gram-negative bacterium capable of entering and growing in alveolar macrophages and monocytes. Complement and complement receptors are important in the uptake of L. pneumophila by human mononuclear phagocytes. The surface molecules of L. pneumophila that activate the complement system are unknown. To identify these factors, we investigated the effects of L. pneumophila lipopolysaccharide (LPS) on the classical and alternative complement pathways of normal human serum by functional hemolytic assays. Although incubation of LPS in normal human serum at 37 degrees C resulted in the activation of both pathways, complement activation proceeded primarily through the classical pathway. Activation of the classical pathway by LPS was dependent on natural antibodies of the immunoglobulin M class that were present in various quantities in sera from different normal individuals but were absent in an immunoglobulin-deficient serum obtained from an agammaglobulinemic patient. Additional studies using sheep erythrocytes coated with LPS suggested that the antibodies recognized antigenic sites in the carbohydrate portion of LPS. The ability of LPS to interact with the complement system suggests a role for LPS in the uptake of L. pneumophila by mononuclear phagocytes. PMID:1612744

  5. Cd47-Signal Regulatory Protein α (Sirpα) Regulates Fcγ and Complement Receptor–Mediated Phagocytosis

    PubMed Central

    Oldenborg, Per-Arne; Gresham, Hattie D.; Lindberg, Frederik P.

    2001-01-01

    In autoimmune hemolytic anemia (AIHA), circulating red blood cells (RBCs) opsonized with autoantibody are recognized by macrophage Fcγ and complement receptors. This triggers phagocytosis and elimination of RBCs from the circulation by splenic macrophages. We recently found that CD47 on unopsonized RBCs binds macrophage signal regulatory protein α (SIRPα), generating a negative signal that prevents phagocytosis of the unopsonized RBCs. We show here that clearance and phagocytosis of opsonized RBCs is also regulated by CD47-SIRPα. The inhibition generated by CD47-SIRPα interaction is strongly attenuated but not absent in mice with only residual activity of the phosphatase Src homology 2 domain–containing protein tyrosine phosphatase (SHP)-1, suggesting that most SIRPα signaling in this system is mediated by SHP-1 phosphatase activity. The macrophage phagocytic response is controlled by an integration of the inhibitory SIRPα signal with prophagocytic signals such as from Fcγ and complement receptor activation. Thus, augmentation of inhibitory CD47-SIRPα signaling may prevent or attenuate RBC clearance in AIHA. PMID:11283158

  6. Anti-Legionella activity of staphylococcal hemolytic peptides.

    PubMed

    Marchand, A; Verdon, J; Lacombe, C; Crapart, S; Héchard, Y; Berjeaud, J M

    2011-05-01

    A collection of various Staphylococci was screened for their anti-Legionella activity. Nine of the tested strains were found to secrete anti-Legionella compounds. The culture supernatants of the strains, described in the literature to produce hemolytic peptides, were successfully submitted to a two step purification process. All the purified compounds, except one, corresponded to previously described hemolytic peptides and were not known for their anti-Legionella activity. By comparison of the minimal inhibitory concentrations, minimal permeabilization concentrations, decrease in the number of cultivable bacteria, hemolytic activity and selectivity, the purified peptides could be separated in two groups. First group, with warnericin RK as a leader, corresponds to the more hemolytic and bactericidal peptides. The peptides of the second group, represented by the PSMα from Staphylococcus epidermidis, appeared bacteriostatic and poorly hemolytic. PMID:21291938

  7. Beta-hemolytic activity of Trichomonas vaginalis correlates with virulence.

    PubMed Central

    Krieger, J N; Poisson, M A; Rein, M F

    1983-01-01

    The reasons that some women develop symptomatic trichomonal vaginitis, whereas many other infected women remain asymptomatic, are unclear, but it has been suggested that Trichomonas vaginalis strains vary in their intrinsic virulence. We describe beta-hemolytic activity in T. vaginalis which correlates with virulence in patients as well as in an animal model and in tissue culture. Fresh T. vaginalis isolates from four women with severe, symptomatic trichomoniasis had high-level (86.3 +/- 6.6%) hemolytic activity, whereas isolates from three completely asymptomatic women had low-level (45.3 +/- 8.4%) hemolytic activity (P less than 0.001). Hemolytic activity also correlated with the production of subcutaneous abscesses in mice (r = 0.74) and with destruction of CHO cell monolayers (r = 0.94). All of the 20 clinical isolates of T. vaginalis tested possessed hemolytic activity. The beta-hemolysin may be a virulence factor for T. vaginalis. Images PMID:6604026

  8. [Treatment and results of therapy in autoimmune hemolytic anemia].

    PubMed

    Tasić, J; Macukanović, L; Pavlović, M; Koraćević, S; Govedarević, N; Kitić, Lj; Tijanić, I; Bakić, M

    1994-01-01

    Basic principles in the therapy of idiopathic autoimmune hemolytic anemia induced by warm antibody were glucocorticoides and splenectomy. Immunosupresive drugs, plasmaferesis and intravenous high doses gamma globulin therapy are also useful. In secundary autoimmune hemolytic anemia induced by warm antibody we treated basic illness. During the period of 1990-1992 we treated 21 patients with primary autoimmune hemolytic anemia and 6 patients with secondary /4 CLL and 2 Non-Hodgkin's lymphoma/. Complete remission we found as a normalisation of reticulocites and hemoglobin level respectively. Complete remission by corticoides we got in 14/21 patients, partial response in 2/21 respectively. Complete response by splenectomy we got in 2/3 splenoctomized patients (idiopathic type). For successful treatment secondary hemolytic anemias we treated primary diseases (CLL and malignant lymphoma) and we got in 4/6 patients complete remission. Our results were standard in both type of autoimmune hemolytic anaemias induced by warm antibody. PMID:18173205

  9. CSF coccidioides complement fixation

    MedlinePlus

    ... eds. Henry's Clinical Diagnosis and Management by Laboratory Methods . 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 61. Read More Complement Update Date 5/1/2015 Updated by: Jatin M. Vyas, MD, ...

  10. Oxidative Damage and Energy Metabolism Disorder Contribute to the Hemolytic Effect of Amorphous Silica Nanoparticles.

    PubMed

    Jiang, Lizhen; Yu, Yongbo; Li, Yang; Yu, Yang; Duan, Junchao; Zou, Yang; Li, Qiuling; Sun, Zhiwei

    2016-12-01

    Amorphous silica nanoparticles (SiNPs) have been extensively used in biomedical applications due to their particular characteristics. The increased environmental and iatrogenic exposure of SiNPs gained great concerns on the biocompatibility and hematotoxicity of SiNPs. However, the studies on the hemolytic effects of amorphous SiNPs in human erythrocytes are still limited. In this study, amorphous SiNPs with 58 nm were selected and incubated with human erythrocytes for different times (30 min and 2 h) at various concentrations (0, 10, 20, 50, and 100 μg/mL). SiNPs induced a dose-dependent increase in percent hemolysis and significantly increased the malondialdehyde (MDA) content and decreased the superoxide dismutase (SOD) activity, leading to oxidative damage in erythrocytes. Hydroxyl radical (·OH) levels were detected by electron spin resonance (ESR), and the decreased elimination rates of ·OH showed SiNPs induced low antioxidant ability in human erythrocytes. Na(+)-K(+) ATPase activity and Ca(2+)-Mg(2+) ATPase activity were found remarkably inhibited after SiNP treatment, possibly causing energy sufficient in erythrocytes. Percent hemolysis of SiNPs was significantly decreased in the presence of N-acetyl-cysteine (NAC) and adenosine diphosphate (ADP). It was concluded that amorphous SiNPs caused dose-dependent hemolytic effects in human erythrocytes. Oxidative damage and energy metabolism disorder contributed to the hemolytic effects of SiNPs in vitro. PMID:26831695

  11. Oxidative Damage and Energy Metabolism Disorder Contribute to the Hemolytic Effect of Amorphous Silica Nanoparticles

    NASA Astrophysics Data System (ADS)

    Jiang, Lizhen; Yu, Yongbo; Li, Yang; Yu, Yang; Duan, Junchao; Zou, Yang; Li, Qiuling; Sun, Zhiwei

    2016-02-01

    Amorphous silica nanoparticles (SiNPs) have been extensively used in biomedical applications due to their particular characteristics. The increased environmental and iatrogenic exposure of SiNPs gained great concerns on the biocompatibility and hematotoxicity of SiNPs. However, the studies on the hemolytic effects of amorphous SiNPs in human erythrocytes are still limited. In this study, amorphous SiNPs with 58 nm were selected and incubated with human erythrocytes for different times (30 min and 2 h) at various concentrations (0, 10, 20, 50, and 100 μg/mL). SiNPs induced a dose-dependent increase in percent hemolysis and significantly increased the malondialdehyde (MDA) content and decreased the superoxide dismutase (SOD) activity, leading to oxidative damage in erythrocytes. Hydroxyl radical (·OH) levels were detected by electron spin resonance (ESR), and the decreased elimination rates of ·OH showed SiNPs induced low antioxidant ability in human erythrocytes. Na+-K+ ATPase activity and Ca2+-Mg2+ ATPase activity were found remarkably inhibited after SiNP treatment, possibly causing energy sufficient in erythrocytes. Percent hemolysis of SiNPs was significantly decreased in the presence of N-acetyl-cysteine (NAC) and adenosine diphosphate (ADP). It was concluded that amorphous SiNPs caused dose-dependent hemolytic effects in human erythrocytes. Oxidative damage and energy metabolism disorder contributed to the hemolytic effects of SiNPs in vitro.

  12. Functional anatomy of complement factor H.

    PubMed

    Makou, Elisavet; Herbert, Andrew P; Barlow, Paul N

    2013-06-11

    Factor H (FH) is a soluble regulator of the proteolytic cascade at the core of the evolutionarily ancient vertebrate complement system. Although FH consists of a single chain of similar protein modules, it has a demanding job description. Its chief role is to prevent complement-mediated injury to healthy host cells and tissues. This entails recognition of molecular patterns on host surfaces combined with control of one of nature's most dangerous examples of a positive-feedback loop. In this way, FH modulates, where and when needed, an amplification process that otherwise exponentially escalates the production of the pro-inflammatory, pro-phagocytic, and pro-cytolytic cleavage products of complement proteins C3 and C5. Mutations and single-nucleotide polymorphisms in the FH gene and autoantibodies against FH predispose individuals to diseases, including age-related macular degeneration, dense-deposit disease, and atypical hemolytic uremic syndrome. Moreover, deletions or variations of genes for FH-related proteins also influence the risk of disease. Numerous pathogens hijack FH and use it for self-defense. As reviewed herein, a molecular understanding of FH function is emerging. While its functional oligomeric status remains uncertain, progress has been achieved in characterizing its three-dimensional architecture and, to a lesser extent, its intermodular flexibility. Models are proposed, based on the reconciliation of older data with a wealth of recent evidence, in which a latent circulating form of FH is activated by its principal target, C3b tethered to a self-surface. Such models suggest hypotheses linking sequence variations to pathophysiology, but improved, more quantitative, functional assays and rigorous data analysis are required to test these ideas. PMID:23701234

  13. Current treatment strategies in autoimmune hemolytic disorders.

    PubMed

    Barcellini, Wilma

    2015-10-01

    Autoimmune hemolytic anemia (AIHA) is a heterogeneous disease usually classified according to the thermal range of the autoantibody in warm, cold and mixed forms. The treatment of AIHA is still not evidence-based. Corticosteroids are the first-line therapy for warm AIHA. For refractory/relapsed cases, the choice is between splenectomy (effective in ∼70% cases but with a presumed cure rate of 20%) and rituximab (effective in ∼70-80% of cases), which is becoming the preferred second-line treatment, and thereafter any of the immunosuppressive drugs (azathioprine, cyclophosphamide, cyclosporin, mycophenolate mofetil). Additional therapies are intravenous immunoglobulins and danazol. For severe or refractory cases, last option treatments are plasma-exchange, high-dose cyclophosphamide and alemtuzumab. As regards cold agglutinin disease, rituximab is now recommended as first-line treatment. PMID:26343892

  14. Complement System Part I – Molecular Mechanisms of Activation and Regulation

    PubMed Central

    Merle, Nicolas S.; Church, Sarah Elizabeth; Fremeaux-Bacchi, Veronique; Roumenina, Lubka T.

    2015-01-01

    Complement is a complex innate immune surveillance system, playing a key role in defense against pathogens and in host homeostasis. The complement system is initiated by conformational changes in recognition molecular complexes upon sensing danger signals. The subsequent cascade of enzymatic reactions is tightly regulated to assure that complement is activated only at specific locations requiring defense against pathogens, thus avoiding host tissue damage. Here, we discuss the recent advances describing the molecular and structural basis of activation and regulation of the complement pathways and their implication on physiology and pathology. This article will review the mechanisms of activation of alternative, classical, and lectin pathways, the formation of C3 and C5 convertases, the action of anaphylatoxins, and the membrane-attack-complex. We will also discuss the importance of structure–function relationships using the example of atypical hemolytic uremic syndrome. Lastly, we will discuss the development and benefits of therapies using complement inhibitors. PMID:26082779

  15. Modeling complement-driven diseases in transgenic mice: Values and limitations.

    PubMed

    Ueda, Yoshiyasu; Gullipalli, Damodar; Song, Wen-Chao

    2016-10-01

    Remarkable advances have been made over past decades in understanding the pathogenesis of complement-mediated diseases. This has led to development of new therapies for, and in some cases re-classification of, complement-driven diseases. This success is due to not only insight from human patients but also studies using transgenic animal models. Animal models that mimic human diseases are useful tools to understand the mechanism of disease and develop new therapies but there are also limitations due to species differences in their complement systems. This review provides a summary of transgenic animal models for three human diseases that are at the forefront of anti-complement therapy, paroxysmal nocturnal hemoglobinuria (PNH), atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy (C3G). They are discussed here as examples to highlight the values and limitations of animal modeling in complement-driven diseases. PMID:27371974

  16. Self-nonself discrimination by the complement system.

    PubMed

    Meri, Seppo

    2016-08-01

    The alternative pathway (AP) of complement can recognize nonself structures by only two molecules, C3b and factor H. The AP deposits C3b covalently on nonself structures via an amplification system. The actual discrimination is performed by factor H, which has binding sites for polyanions (sialic acids, glycosaminoglycans, phospholipids). This robust recognition of 'self' protects our own intact viable cells and tissues, while activating structures are recognized by default. Foreign targets are opsonized for phagocytosis or killed. Mutations in factor H predispose to severe diseases. In hemolytic uremic syndrome, they promote complement attack against blood cells and vascular endothelial cells and lead, for example, to kidney and brain damage. Even pathogens can exploit factor H. In fact, the ability to bind factor H discriminates most pathogenic microbes from nonpathogenic ones. PMID:27393384

  17. Lactobacilli Interfere with Streptococcus pyogenes Hemolytic Activity and Adherence to Host Epithelial Cells.

    PubMed

    Saroj, Sunil D; Maudsdotter, Lisa; Tavares, Raquel; Jonsson, Ann-Beth

    2016-01-01

    Streptococcus pyogenes [Group A streptococcus (GAS)], a frequent colonizer of the respiratory tract mucosal surface, causes a variety of human diseases, ranging from pharyngitis to the life-threatening streptococcal toxic shock-like syndrome. Lactobacilli have been demonstrated to colonize the respiratory tract. In this study, we investigated the interference of lactobacilli with the virulence phenotypes of GAS. The Lactobacillus strains L. rhamnosus Kx151A1 and L. reuteri PTA-5289, but not L. salivarius LMG9477, inhibited the hemolytic activity of S. pyogenes S165. The inhibition of hemolytic activity was attributed to a decrease in the production of streptolysin S (SLS). Conditioned medium (CM) from the growth of L. rhamnosus Kx151A1 and L. reuteri PTA-5289 was sufficient to down-regulate the expression of the sag operon, encoding SLS. The Lactobacillus strains L. rhamnosus Kx151A1, L. reuteri PTA-5289, and L. salivarius LMG9477 inhibited the initial adherence of GAS to host epithelial cells. Intriguingly, competition with a combination of Lactobacillus species reduced GAS adherence to host cells most efficiently. The data suggest that an effector molecule released from certain Lactobacillus strains attenuates the production of SLS at the transcriptional level and that combinations of Lactobacillus strains may protect the pharyngeal mucosa more efficiently from the initial colonization of GAS. The effector molecules released from Lactobacillus strains affecting the virulence phenotypes of pathogens hold potential in the development of a new generation of therapeutics. PMID:27524981

  18. Lactobacilli Interfere with Streptococcus pyogenes Hemolytic Activity and Adherence to Host Epithelial Cells

    PubMed Central

    Saroj, Sunil D.; Maudsdotter, Lisa; Tavares, Raquel; Jonsson, Ann-Beth

    2016-01-01

    Streptococcus pyogenes [Group A streptococcus (GAS)], a frequent colonizer of the respiratory tract mucosal surface, causes a variety of human diseases, ranging from pharyngitis to the life-threatening streptococcal toxic shock-like syndrome. Lactobacilli have been demonstrated to colonize the respiratory tract. In this study, we investigated the interference of lactobacilli with the virulence phenotypes of GAS. The Lactobacillus strains L. rhamnosus Kx151A1 and L. reuteri PTA-5289, but not L. salivarius LMG9477, inhibited the hemolytic activity of S. pyogenes S165. The inhibition of hemolytic activity was attributed to a decrease in the production of streptolysin S (SLS). Conditioned medium (CM) from the growth of L. rhamnosus Kx151A1 and L. reuteri PTA-5289 was sufficient to down-regulate the expression of the sag operon, encoding SLS. The Lactobacillus strains L. rhamnosus Kx151A1, L. reuteri PTA-5289, and L. salivarius LMG9477 inhibited the initial adherence of GAS to host epithelial cells. Intriguingly, competition with a combination of Lactobacillus species reduced GAS adherence to host cells most efficiently. The data suggest that an effector molecule released from certain Lactobacillus strains attenuates the production of SLS at the transcriptional level and that combinations of Lactobacillus strains may protect the pharyngeal mucosa more efficiently from the initial colonization of GAS. The effector molecules released from Lactobacillus strains affecting the virulence phenotypes of pathogens hold potential in the development of a new generation of therapeutics. PMID:27524981

  19. Complement component 3 (C3)

    MedlinePlus

    C3 and C4 are the most commonly measured complement components. A complement test may be used to monitor people with an ... normal levels of the complement proteins C3 and C4 . Complement activity varies throughout the body. For example, ...

  20. Utilizing complement evasion strategies to design complement-based antibacterial immunotherapeutics: Lessons from the pathogenic Neisseriae.

    PubMed

    Ram, Sanjay; Shaughnessy, Jutamas; DeOliveira, Rosane B; Lewis, Lisa A; Gulati, Sunita; Rice, Peter A

    2016-10-01

    Novel therapies are urgently needed to combat the global threat of multidrug-resistant pathogens. Complement forms an important arm of innate defenses against infections. In physiological conditions, complement activation is tightly controlled by soluble and membrane-associated complement inhibitors, but must be selectively activated on invading pathogens to facilitate microbial clearance. Many pathogens, including Neisseria gonorrhoeae and N. meningitidis, express glycans, including N-acetylneuraminic acid (Neu5Ac), that mimic host structures to evade host immunity. Neu5Ac is a negatively charged 9-cabon sugar that inhibits complement, in part by enhancing binding of the complement inhibitor factor H (FH) through C-terminal domains (19 and 20) on FH. Other microbes also bind FH, in most instances through FH domains 6 and 7 or 18-20. Here we describe two strategies to target complement activation on Neisseriae. First, microbial binding domains of FH were fused to IgG Fc to create FH18-20/Fc (binds gonococci) and FH6,7/Fc (binds meningococci). A point mutation in FH domain 19 eliminated hemolysis caused by unmodified FH18-20, but retained binding to gonococci. FH18-20/Fc and FH6,7/Fc mediated complement-dependent killing in vitro and showed efficacy in animal models of gonorrhea and meningococcal bacteremia, respectively. The second strategy utilized CMP-nonulosonate (CMP-NulO) analogs of sialic acid that were incorporated into LOS and prevented complement inhibition by physiologic CMP-Neu5Ac and resulted in attenuated gonococcal infection in mice. While studies to establish the safety of these agents are needed, enhancing complement activation on microbes may represent a promising strategy to treat antimicrobial resistant organisms. PMID:27297292

  1. Roles of the valine clusters in domain 3 of the hemolytic lectin CEL-III in its oligomerization and hemolytic abilities.

    PubMed

    Hisamatsu, Keigo; Unno, Hideaki; Goda, Shuichiro; Hatakeyama, Tomomitsu

    2009-01-01

    The hemolytic lectin CEL-III and its site-directed mutants were expressed in Escherichia coli cells. Replacement of the valine clusters in domain 3 with alanine residues led to increased self-oligomerization in solution and higher hemolytic activity. The results suggest the involvement of these valine clusters in CEL-III oligomerization and hemolytic activity. PMID:19356139

  2. Gastric Mucormycosis with Hemolytic Uremic Syndrome.

    PubMed

    Raviraj, K Sunil; Miglani, P; Garg, A; Agarwal, P K

    2015-10-01

    Mucormycosis, is an emerging fungal infection in immunocompromised and diabetic individuals, usually affects rhino-orbito-cerebral, cutaneous and pulmonary regions. But mucormycosis in immunocompetent environment is rare and occurrence of gastric mucormycosis is unusual. We report a case of 19 year old female, with no pre-existing co-morbidities, presented with fever, dysentery, vomiting, and melena for 4 days. On evaluation she was found to have pancytopenia, acute kidney injury, hemolytic anemia, coagulopathy and hepatic derangement and treated with hemodialysis, plasmapheresis along with antibiotics and packed cell RBC transfusion. Upper gastrointestinal endoscopy revealed presence of extensive esophageal and gastric ulcer. In view of persistent bleeding despite endoscopic sclerotherapy, repetition of upper gastrointestinal endoscopy and CT abdomen with oral contrast was done, which revealed perforated gastric ulcer. Exploratory laparotomy and excision of ulcer was done. The biopsy of gastric ulcer had shown the presence of granulomatous necrotic areas positive for mucormycosis. Then she was managed with amphotericin-B, posoconazole with which she improved. PMID:27608699

  3. [Drug induced hemolytic anemia associated with agranulocytosis].

    PubMed

    Satoh, S; Takahashi, T; Hayashi, T; Okada, Y; Tokunoh, T; Adachi, M; Hinoda, Y; Endoh, T; Imai, K

    1996-10-01

    A 27-year-old female was admitted to a hospital because of severe anemia (hemoglobin 4.9 g/dl) after taking PL (a drug for common cold consisted of Salicylamide, Acetaminophen, Caffeine and Promethazine methylene di-salicylate) and Cefadroxil (an oral antibiotic) for ten days. History and laboratory data leaded to a diagnosis of drug induced hemolytic anemia. 6 units of concentrated red blood cells were transfused and the suspected drugs were discontinued immediately. Though resolution of anemia and no further hemolysis were observed, progressive leukocytopenia developed since four days after the admission. Bone marrow aspiration revealed marked decrease of granulocytic series. The patient was transferred to our hospital and was isolated under laminar air-flow to prevent her from bacterial and fungal infections. She was treated with prednisolone and granulocyte-colony stimulating factor. She recovered from leukocytopenia in two weeks without suffering from any life-threatening infection. We extensively analyzed the suspected drugs and mechanism of hemolysis and granulocytopenia. Cefadroxil is turned out to be contributed to hemolysis by an immune complex mechanism. Cefadroxil and Salicylamide were suggested to be involved in granulocytopenia by the induction of antibodies against the leukocytes to which these drugs were bound. Thus Cefadroxil was regarded as a causative drug of both hemolysis and granulocytopenia. This case is of interest for analyzing drug-induced blood abnormality because it is very rare that two lineage of blood were injured by one drug at the same time as far as we know. PMID:8952318

  4. Autoimmune hemolytic anemia: From lab to bedside.

    PubMed

    Chaudhary, R K; Das, Sudipta Sekhar

    2014-01-01

    Autoimmune hemolytic anemia (AIHA) is not an uncommon clinical disorder and requires advanced, efficient immunohematological and transfusion support. Many AIHA patients have underlying disorder and therefore, it is incumbent upon the clinician to investigate these patients in detail, as the underlying condition can be of a serious nature such as lymphoproliferative disorder or connective tissue disorder. Despite advances in transfusion medicine, simple immunohematological test such as direct antiglobulin test (DAT) still remains the diagnostic hallmark of AIHA. The sensitive gel technology has enabled the immunohematologist not only to diagnose serologically such patients, but also to characterize red cell bound autoantibodies with regard to their class, subclass and titer in a rapid and simplified way. Detailed characterization of autoantibodies is important, as there is a relationship between in vivo hemolysis and strength of DAT; red cell bound multiple immunoglobulins, immunoglobulin G subclass and titer. Transfusing AIHA patient is a challenge to the immunohematologist as it is encountered with difficulties in ABO grouping and cross matching requiring specialized serological tests such as alloadsorption or autoadsorption. At times, it may be almost impossible to find a fully matched unit to transfuse these patients. However, transfusion should not be withheld in a critically ill patient even in the absence of compatible blood. The "best match" or "least incompatible units" can be transfused to such patients under close supervision without any serious side-effects. All blood banks should have the facilities to perform the necessary investigations required to issue "best match" packed red blood cells in AIHA. Specialized techniques such as elution and adsorption, which at times are helpful in enhancing blood safety in AIHA should be established in all transfusion services. PMID:24678166

  5. Pregnancy-Associated Atypical Hemolytic-Uremic Syndrome

    PubMed Central

    Saad, Antonio F.; Roman, Jorge; Wyble, Aaron; Pacheco, Luis D.

    2016-01-01

    Précis Introduction Early diagnosis of atypical uremic–hemolytic syndrome may be challenging during the puerperium period. Correct diagnosis and timely management are crucial to improve outcomes. Background Pregnancy-associated atypical hemolytic-uremic syndrome (p-aHUS) is a rare condition characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. Triggered by pregnancy, genetically predisposed women develop the syndrome, leading to a disastrous hemolytic disease characterized by diffuse endothelial damage and platelet consumption. This disease is a life-threatening condition that requires prompt diagnosis and therapy. Case A 19-year-old G1P1 Caucasian female with suspicion of HELLP syndrome was treated at our facility for severe thrombocytopenia and acute kidney injury. A diagnosis of atypical uremic–hemolytic syndrome was later confirmed. The patient's condition improved with normalization of platelets and improvement in kidney function after 14 days of plasmapheresis. She was subsequently treated with eculizumab, a monoclonal antibody against C5. The patient tolerated well the therapy and is currently in remission. Conclusion Diagnosis of p-aHUS is challenging, as it can mimic various diseases found during pregnancy and the postpartum. Plasma exchange should be promptly initiated within 24 hours of diagnosis. Eculizumab has risen to become an important tool to improve long-term comorbidities and mortality in this group population. PMID:26989566

  6. Pregnancy-Associated Atypical Hemolytic-Uremic Syndrome.

    PubMed

    Saad, Antonio F; Roman, Jorge; Wyble, Aaron; Pacheco, Luis D

    2016-03-01

    Introduction Early diagnosis of atypical uremic-hemolytic syndrome may be challenging during the puerperium period. Correct diagnosis and timely management are crucial to improve outcomes. Background Pregnancy-associated atypical hemolytic-uremic syndrome (p-aHUS) is a rare condition characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. Triggered by pregnancy, genetically predisposed women develop the syndrome, leading to a disastrous hemolytic disease characterized by diffuse endothelial damage and platelet consumption. This disease is a life-threatening condition that requires prompt diagnosis and therapy. Case A 19-year-old G1P1 Caucasian female with suspicion of HELLP syndrome was treated at our facility for severe thrombocytopenia and acute kidney injury. A diagnosis of atypical uremic-hemolytic syndrome was later confirmed. The patient's condition improved with normalization of platelets and improvement in kidney function after 14 days of plasmapheresis. She was subsequently treated with eculizumab, a monoclonal antibody against C5. The patient tolerated well the therapy and is currently in remission. Conclusion Diagnosis of p-aHUS is challenging, as it can mimic various diseases found during pregnancy and the postpartum. Plasma exchange should be promptly initiated within 24 hours of diagnosis. Eculizumab has risen to become an important tool to improve long-term comorbidities and mortality in this group population. PMID:26989566

  7. Complement-mediated antiinflammatory effect of bisbenzylisoquinoline alkaloid fangchinoline.

    PubMed

    Hristova, M; Istatkova, R

    1999-11-01

    Complement-mediated mode of action of bisbenzylisoquinoline alkaloid fangchinoline was investigated in vivo and in vitro. The application of fangchinoline intraperitoneally (i.p.) to complement normal mice, strain ICR, inhibited the complement activity in serum and peritoneal exudate. The substance activated serum complement of C5-deficient DBA/2 mice. Fangchinoline was able to provoke local inflammatory reaction in both strains after subcutaneous (s.c.) injection. The alkaloid suppressed paw swelling induced by live Candida albicans in ICR and DBA/2 mice. Its effect depended on the dose and time of injection prior to inflammatory reaction. The in vitro experiments proved the interference of fangchinoline action with post-C5 reactions. The substance augmented C5-convertase formation and functional activity. These results are in correspondence with our previous investigations, proving the complement-mediated action of fangchinoline. The antiinflammatory effect could be a consequence of the caused complement exhaustion. PMID:11962544

  8. Vitronectin-binding staphylococci enhance surface-associated complement activation.

    PubMed Central

    Lundberg, F; Lea, T; Ljungh, A

    1997-01-01

    Coagulase-negative staphylococci are well recognized in medical device-associated infections. Complement activation is known to occur at the biomaterial surface, resulting in unspecific inflammation around the biomaterial. The human serum protein vitronectin (Vn), a potent inhibitor of complement activation by formation of an inactive terminal complement complex, adsorbs to biomaterial surfaces in contact with blood. In this report, we discuss the possibility that surface-immobilized Vn inhibits complement activation and the effect of Vn-binding staphylococci on complement activation on surfaces precoated with Vn. The extent of complement activation was measured with a rabbit anti-human C3c antibody and a mouse anti-human C9 antibody, raised against the neoepitope of C9. Our data show that Vn immobilized on a biomaterial surface retains its ability to inhibit complement activation. The additive complement activation-inhibitory effect of Vn on a heparinized surface is very small. In the presence of Vn-binding strain, Staphylococcus hemolyticus SM131, complement activation on a surface precoated with Vn occurred as it did in the absence of Vn precoating. For S. epidermidis 3380, which does not express binding of Vn, complement activation on a Vn-precoated surface was significantly decreased. The results could be repeated on heparinized surfaces. These data suggest that Vn adsorbed to a biomaterial surface may serve to protect against surface-associated complement activation. Furthermore, Vn-binding staphylococcal cells may enhance surface-associated complement activation by blocking the inhibitory effect of preadsorbed Vn. PMID:9038294

  9. Construction of an immunotoxin by linking a monoclonal antibody against the human epidermal growth factor receptor and a hemolytic toxin.

    PubMed

    Avila, Ana D; Calderón, Carlos F; Pérez, Rita M; Pons, Carmen; Pereda, Celia M; Ortiz, Ana R

    2007-01-01

    Hybrid molecules obtained through conjugation of monoclonal antibodies and toxins constitute an approach under exploration to generate potential agents for the treatment of cancer and other diseases. A frequently employed toxic component in the construction of such immunotoxins is ricin, a plant toxin which inhibits protein synthesis at ribosomal level and so requires to be internalized by the cell. A hemolytic toxin isolated from the sea anemone Stichodactyla helianthus, which is active at the cell membrane level, was linked through a disulfide bond to the anti-epidermal growth factor receptor monoclonal antibody ior egf/r3. The resulting immunotoxin did not exhibit hemolytic activity except under reducing conditions. It was toxic for H125 cells that express the human epidermal growth factor receptor, but non-toxic for U1906 cells that do not express this receptor. PMID:18064354

  10. The relative merits of therapies being developed to tackle inappropriate ('self'-directed) complement activation.

    PubMed

    Antwi-Baffour, Samuel; Kyeremeh, Ransford; Adjei, Jonathan Kofi; Aryeh, Claudia; Kpentey, George

    2016-12-01

    The complement system is an enzyme cascade that helps defend against infection. Many complement proteins occur in serum as inactive enzyme precursors or reside on cell surfaces. Complement components have many biologic functions and their activation can eventually damage the plasma membranes of cells and some bacteria. Although a direct link between complement activation and autoimmune diseases has not been found, there is increasing evidence that complement activation significantly contributes to the pathogenesis of a large number of inflammatory diseases that may have autoimmune linkage. The inhibition of complement may therefore be very important in a variety of autoimmune diseases since their activation may be detrimental to the individual involved. However, a complete and long-term inhibition of complement may have some contra side effects such as increased susceptibility to infection. The site of complement activation will, however, determine the type of inhibitor to be used, its route of application and dosage level. Compared with conventional drugs, complement inhibitors may be the best option for treatment of autoimmune diseases. The review takes a critical look at the relative merits of therapies being developed to tackle inappropriate complement activation that are likely to result in sporadic autoimmune diseases or worsen already existing one. It covers the complement system, general aspects of complement inhibition therapy, therapeutic strategies and examples of complement inhibitors. It concludes by highlighting on the possibility that a better inhibitor of complement activation when found will help provide a formidable treatment for autoimmune diseases as well as preventing one. PMID:26935316

  11. Complement, complement activation and anaphylatoxins in human ovarian follicular fluid.

    PubMed Central

    Perricone, R; de Carolis, C; Moretti, C; Santuari, E; de Sanctis, G; Fontana, L

    1990-01-01

    Functionally active complement was sought and detected in human follicular fluids obtained during the pre-ovulatory period. All the functional complement activities tested, including total haemolytic complement, classical pathway activity and alternative pathway activity were present in nine fluids from four different donors with values within the normal serum range. The immunochemical analysis demonstrated the presence of complement factors from C1 to C9, of B and of C1 INH, H, I. Complement anaphylatoxins were found employing RIA techniques in amounts significantly higher than in human plasma, thus demonstrating that follicular fluid complement, at least during the pre-ovulatory period, is partially activated. A possible role for urokinase-like substances in such an activation was indicated by further in vitro experiments. The presence of active complement in follicular fluid can be relevant for the function of the enzymatic multi-factorial mechanism of ovulation. PMID:2242616

  12. Complement amplification revisited.

    PubMed

    Lutz, Hans U; Jelezarova, Emiliana

    2006-01-01

    Complement amplification in blood takes place not only on activating surfaces, but in plasma as well, where it is maintained primarily by C3b2-IgG complexes. Regular products of C3 activation in serum, these complexes are inherently very efficient precursors of the alternative pathway C3 convertase. Moreover, they can bind properdin bivalently, thus creating preferred sites for convertase formation. C3b2-IgG complexes have a half-life that is substantially longer than that of free C3b, since both C3b molecules are partially protected from inactivation by factor H and I. These complexes are preferentially generated on certain naturally occurring and induced antibodies that exhibit a paratope-independent affinity for C3/C3b. Such antibodies are known to stimulate alternative complement pathway activation. We have assembled the evidence for the generation and the functional potency of the C3b2-IgG complexes, which have been studied during the last two decades. We illustrate their roles in immune complex solubilization, phagocytosis, immune response, and their ability to initiate devastating effects in ischemia/reperfusion and in aggravating inflammation. PMID:16023211

  13. Group A β-hemolytic streptococcal pharyngotonsillitis outbreak.

    PubMed

    Culqui, Dante R; Manzanares-Laya, Sandra; Van Der Sluis, Sarah Lafuente; Fanlo, Albert Anton; Comas, Rosa Bartolomé; Rossi, Marcello; Caylá, Joán A

    2014-04-01

    The aim was to describe an outbreak of group A β-hemolytic streptococcal pharyngotonsillitis in health care professionals. This is a cross-sectional descriptive study of 17 clients who dined at the same table in a restaurant in Barcelona in July 2012. The frequency, timing and severity of symptoms were analyzed, as were demographic variables and others concerning the food ingested. The attack rate was 58.8%. Six of the 10 clients were positive for group A β-hemolytic streptococcal. Six of the 13 individuals who handled the food involved in the dinner had symptoms. No association was identified with the food consumed. There is epidemiological evidence of foodborne group A β-hemolytic streptococcal transmission, but respiratory transmission could not be ruled out. PMID:24897054

  14. Group A β-hemolytic streptococcal pharyngotonsillitis outbreak

    PubMed Central

    Culqui, Dante R; Manzanares-Laya, Sandra; Van Der Sluis, Sarah Lafuente; Fanlo, Albert Anton; Comas, Rosa Bartolomé; Rossi, Marcello; Caylá, Joán A

    2014-01-01

    The aim was to describe an outbreak of group A β-hemolytic streptococcal pharyngotonsillitis in health care professionals. This is a cross-sectional descriptive study of 17 clients who dined at the same table in a restaurant in Barcelona in July 2012. The frequency, timing and severity of symptoms were analyzed, as were demographic variables and others concerning the food ingested. The attack rate was 58.8%. Six of the 10 clients were positive for group A β-hemolytic streptococcal. Six of the 13 individuals who handled the food involved in the dinner had symptoms. No association was identified with the food consumed. There is epidemiological evidence of foodborne group A β-hemolytic streptococcal transmission, but respiratory transmission could not be ruled out. PMID:24897054

  15. Diagnosis and management of rare congenital nonimmune hemolytic disease.

    PubMed

    Gallagher, Patrick G

    2015-01-01

    Rare, congenital nonimmune hemolytic disorders of the erythrocyte, although uncommon, are important causes of anemia in the child and adult. These are a heterogeneous group of diseases that disrupt normal erythrocyte structure and function in varying ways. Predominant are abnormalities of hemoglobin stability, defects of erythrocyte metabolism, and disorders of erythrocyte hydration. Unstable hemoglobinopathies may lead to chronic or episodic hemolysis. Perturbation of critical enzymes of the Embden-Meyerhof pathway lead to altered erythrocyte metabolism and chronic hemolysis. Disorders of erythrocyte hydration are an under-recognized cause of hemolytic anemia. Beyond pathophysiologic mechanisms of disease, clinical, laboratory, and genetic heterogeneity characterize this group of disorders. Often, they are underdiagnosed or misdiagnosed. This review discusses pathophysiology, inheritance, clinical findings, laboratory manifestations, and management considerations in several rare nonimmune hemolytic diseases including the unstable hemoglobins, disorders of erythrocyte metabolism, and abnormalities of erythrocyte hydration. PMID:26637748

  16. Variation in hemolytic activity of Brachyspira hyodysenteriae strains from pigs.

    PubMed

    Mahu, Maxime; De Pauw, Nele; Vande Maele, Lien; Verlinden, Marc; Boyen, Filip; Ducatelle, Richard; Haesebrouck, Freddy; Martel, An; Pasmans, Frank

    2016-01-01

    Brachyspira hyodysenteriae is the primary cause of swine dysentery, which is responsible for major economic losses to the pig industry worldwide. The hemolytic activity of 10 B. hyodysenteriae strains isolated from stools of pigs with mild to mucohemorrhagic diarrhea was compared and seven hemolysis associated genes were sequenced. Hemolysis induced by these strains varied from strong to near absent. One weakly hemolytic B. hyodysenteriae strain showed sequence changes in five hemolysis associated genes (tlyA, tlyB, hemolysin III, hemolysin activation protein and hemolysin III channel protein) resulting in amino acid substitutions. The occurrence of weakly hemolytic strains identifiable as B. hyodysenteriae should be taken into account in swine dysentery diagnostics. The presence of these strains may affect herd dysentery status, with great impact on a farms trading opportunities. PMID:27338265

  17. Membrane cofactor protein mutations in atypical hemolytic uremic syndrome (aHUS), fatal Stx-HUS, C3 glomerulonephritis, and the HELLP syndrome

    PubMed Central

    Fang, Celia J.; Fremeaux-Bacchi, Veronique; Liszewski, M. Kathryn; Pianetti, Gaia; Noris, Marina; Goodship, Timothy H. J.

    2008-01-01

    The hemolytic uremic syndrome (HUS) is a triad of microangiopathic hemolytic anemia, thrombocytopenia, and renal impairment. Genetic studies demonstrate that heterozygous mutations of membrane cofactor protein (MCP;CD46) predispose to atypical HUS (aHUS), which is not associated with exposure to Shiga toxin (Stx). Among the initial 25 MCP mutations in patients with aHUS were 2, R69W and A304V, that were expressed normally and for which no dysfunction was found. The R69W mutation is in complement control protein module 2, while A304V is in the hydrophobic transmembrane domain. In addition to 3 patients with aHUS, the A304V mutation was identified in 1 patient each with fatal Stx-HUS, the HELLP (hemolysis, elevated liver enzymes, and low platelets) syndrome, and glomerulonephritis with C3 deposits. A major goal was to assess if these putative mutations lead to defective complement regulation. Permanent cell lines expressing the mutated proteins were complement “challenged,” and membrane control of C3 fragment deposition was monitored. Both the R69W and A304V MCP mutations were deficient in their ability to control the alternative pathway of complement activation on a cell surface, illustrating the importance of modeling transmembrane proteins in situ. PMID:17914026

  18. Coomb’s Positive Hemolytic Anemia Due To Insect Bite

    PubMed Central

    2007-01-01

    Hemolytic anemia has occasionally been described in association with insect bites. The venom of certain spiders, bees and wasps, and some snakes can rarely cause intravascular hemolysis. We report here a case of Coombs positive hemolytic anemia due to an insect bite. These bites often pose diagnostic challenges and when associated with systemic manifestations necessitate early intervention. This communication reviews the clinico- hematologic spectrum in these cases and also emphasizes the need to capture the insect as identification would help in early diagnosis and management. PMID:22400097

  19. Clinical guides for atypical hemolytic uremic syndrome in Japan.

    PubMed

    Kato, Hideki; Nangaku, Masaomi; Hataya, Hiroshi; Sawai, Toshihiro; Ashida, Akira; Fujimaru, Rika; Hidaka, Yoshihiko; Kaname, Shinya; Maruyama, Shoichi; Yasuda, Takashi; Yoshida, Yoko; Ito, Shuichi; Hattori, Motoshi; Miyakawa, Yoshitaka; Fujimura, Yoshihiro; Okada, Hirokazu; Kagami, Shoji

    2016-08-01

    Atypical hemolytic uremic syndrome (aHUS) is a rare disease characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. In 2013, we developed diagnostic criteria to enable early diagnosis and timely initiation of appropriate treatment for aHUS. Recent clinical and molecular findings have resulted in several proposed classifications and definitions of thrombotic microangiopathy and aHUS. Based on recent advances in this field and the emerging international consensus to exclude secondary TMAs from the definition of aHUS, we have redefined aHUS and proposed diagnostic algorithms, differential diagnosis, and therapeutic strategies for aHUS. PMID:27422619

  20. Clinical guides for atypical hemolytic uremic syndrome in Japan.

    PubMed

    Kato, Hideki; Nangaku, Masaomi; Hataya, Hiroshi; Sawai, Toshihiro; Ashida, Akira; Fujimaru, Rika; Hidaka, Yoshihiko; Kaname, Shinya; Maruyama, Shoichi; Yasuda, Takashi; Yoshida, Yoko; Ito, Shuichi; Hattori, Motoshi; Miyakawa, Yoshitaka; Fujimura, Yoshihiro; Okada, Hirokazu; Kagami, Shoji

    2016-07-01

    Atypical hemolytic uremic syndrome (aHUS) is a rare disease characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. In 2013, we developed diagnostic criteria to enable early diagnosis and timely initiation of appropriate treatment for aHUS. Recent clinical and molecular findings have resulted in several proposed classifications and definitions of thrombotic microangiopathy and aHUS. Based on recent advances in this field and the emerging international consensus to exclude secondary TMAs from the definition of aHUS, we have redefined aHUS and proposed diagnostic algorithms, differential diagnosis, and therapeutic strategies for aHUS. PMID:27460397

  1. Eculizumab is a safe and effective treatment in pediatric patients with atypical hemolytic uremic syndrome.

    PubMed

    Greenbaum, Larry A; Fila, Marc; Ardissino, Gianluigi; Al-Akash, Samhar I; Evans, Jonathan; Henning, Paul; Lieberman, Kenneth V; Maringhini, Silvio; Pape, Lars; Rees, Lesley; van de Kar, Nicole C A J; Vande Walle, Johan; Ogawa, Masayo; Bedrosian, Camille L; Licht, Christoph

    2016-03-01

    Atypical hemolytic uremic syndrome (aHUS) is caused by alternative complement pathway dysregulation, leading to systemic thrombotic microangiopathy (TMA) and severe end-organ damage. Based on 2 prospective studies in mostly adults and retrospective data in children, eculizumab, a terminal complement inhibitor, is approved for aHUS treatment. Here we prospectively evaluated efficacy and safety of weight-based dosing of eculizumab in eligible pediatric patients with aHUS in an open-label phase II study. The primary end point was complete TMA response by 26 weeks. Twenty-two patients (aged 5 months-17 years) were treated; 16 were newly diagnosed, 12 had no prior plasma exchange/infusion during current TMA symptomatology, 11 received baseline dialysis, and 2 had prior renal transplants. By week 26, 14 achieved a complete TMA response, 18 achieved hematologic normalization, and 16 had 25% or better improvement in serum creatinine. Plasma exchange/infusion was discontinued in all, and 9 of the 11 patients who required dialysis at baseline discontinued, whereas none initiated new dialysis. Eculizumab was well tolerated; no deaths or meningococcal infections occurred. Bone marrow failure, wrist fracture, and acute respiratory failure were reported as unrelated severe adverse events. Thus, our findings establish the efficacy and safety of eculizumab for pediatric patients with aHUS and are consistent with proposed immediate eculizumab initiation following diagnosis in children. PMID:26880462

  2. Rare Occurrence of 3 "H": Hypercalcemia, Hemolytic Anemia and Hodgkin's Lymphoma.

    PubMed

    Jain, Ankur; Malhotra, Pankaj; Prakash, Gaurav; Varma, Subhash; Kumar, Narender; Das, Asim

    2016-06-01

    Clinicians in hematology practice commonly encounter anemia, hypercalcemia and renal failure, which when present in combination evoke a diagnostic workup for multiple myeloma. We report a 71-years old lady who presented to our hematology clinic with fever and easy fatiguability of 3 months duration and on investigations was found to have anemia and hypercalcemia. Direct Coomb's test characterized the anemia as complement mediated (anti-C3d) hemolysis. Biochemical investigations revealed normal 25(OH) Vitamin D3 and suppressed Parathormone levels and a negative workup for plasma cell dyscrasias, sarcoidosis and autoimmune disorders. CT scan revealed a paravertebral mass with cervical, supraclavicular and abdominal lymphadenopathy along with splenomegaly and left pleural effusion. Biopsy from the paravertebral mass confirmed the diagnosis of Hodgkin's disease (nodular sclerosis) using immunohistochemistry. Bone marrow examination suggested infiltration by lymphoma. Hypercalcemia was managed with saline and zoledronic acid. Administration of prednisolone (1 mg/kg/day) along with chemotherapy (ABVD regimen) led to normalization of calcium and hemoglobin levels. However, hemolysis recurred 2 weeks later and hence, Rituximab (375 mg/m(2)) was administered on a weekly schedule for 4 doses and ABVD (2 weekly) was continued, which brought hemolysis under control. Co-occurrence of two paraneoplastic manifestations (complement mediated hemolytic anemia and hypercalcemia) in Hodgkin's lymphoma is very unusual. Present report aims not only to highlight a rare presentation of Hodgkin's lymphoma but also focus on the role of Rituximab in controlling hemolysis associated with this disease. PMID:27408382

  3. Complementing Gender Analysis Methods.

    PubMed

    Kumar, Anant

    2016-01-01

    The existing gender analysis frameworks start with a premise that men and women are equal and should be treated equally. These frameworks give emphasis on equal distribution of resources between men and women and believe that this will bring equality which is not always true. Despite equal distribution of resources, women tend to suffer and experience discrimination in many areas of their lives such as the power to control resources within social relationships, and the need for emotional security and reproductive rights within interpersonal relationships. These frameworks believe that patriarchy as an institution plays an important role in women's oppression, exploitation, and it is a barrier in their empowerment and rights. Thus, some think that by ensuring equal distribution of resources and empowering women economically, institutions like patriarchy can be challenged. These frameworks are based on proposed equality principle which puts men and women in competing roles. Thus, the real equality will never be achieved. Contrary to the existing gender analysis frameworks, the Complementing Gender Analysis framework proposed by the author provides a new approach toward gender analysis which not only recognizes the role of economic empowerment and equal distribution of resources but suggests to incorporate the concept and role of social capital, equity, and doing gender in gender analysis which is based on perceived equity principle, putting men and women in complementing roles that may lead to equality. In this article the author reviews the mainstream gender theories in development from the viewpoint of the complementary roles of gender. This alternative view is argued based on existing literature and an anecdote of observations made by the author. While criticizing the equality theory, the author offers equity theory in resolving the gender conflict by using the concept of social and psychological capital. PMID:25941756

  4. Examining coagulation-complement crosstalk: complement activation and thrombosis.

    PubMed

    Foley, Jonathan H

    2016-05-01

    The coagulation and complement systems are ancestrally related enzymatic cascades of the blood. Although their primary purposes have diverged over the past few hundred million years, they remain inextricably connected. Both complement and coagulation systems limit infection by pathogens through innate immune mechanisms. Recently, it has been shown that hyperactive complement (in particular, elevated C5a/C5b-9) is involved in the pathogenesis (including thrombosis) of diseases such as paroxysmal nocturnal hemoglobinuria, atypical haemolytic uremic syndrome, antiphospholipid syndrome and bacteremia. Although these diseases together account for many thrombosis cases, there are many more where complement activation is not considered a causative factor leading to thrombosis. To better understand what role complement may play in the pathogenesis of thrombosis a better understanding of the mechanisms that cause over-active complement in thrombotic disease is required. PMID:27207425

  5. Complete absence of the third component of complement in man.

    PubMed Central

    Ballow, M; Shira, J E; Harden, L; Yang, S Y; Day, N K

    1975-01-01

    A 4-yr-old female patient who has recurrent infections with encapsulated bacteria and gramnegative organisms was found to have a complete absence of total hemolytic complement and C3. Total hemolytic complement was reconstituted by the addition of functionally pure C3. With the exception of a moderately reduced homolytic C4, all other C components, measured homolytically and by radial immunodiffusion, were present in normal amounts. By Ouchterlong analysis, the patient's serum contained C3b inactivator and properdin but no antigenic C3. Activation of the alternate pathway was examined by purified cobra venom factor (CVF) and inulin. Neither of these substances led to activation of properdin factor B to B. On addition of partially purified Cordis C3, in four out of four instances and with different preparations of Cordis C3, activation of factor B to B occurred in the inulin-serum-C3 mixture. In contrast, activation of factor B to B occurred only once out of four times with CVF-serum-C3 mixtures. Immune adherence was found to be normal in the patient's serum and could be removed by anti-C4 antiserum of hydrazine treatment. A marked opsonic defect was present against Escherichia coli. Serum bactericidal activity against a rough strain of E. coli was also defective. The ability to mobilize an infalmmatory response was examined by Rebuck skin window technique. A delay in neutrophil migration occurred until the 6th h. In vitro lymphocyte transformation and serum immunoglobulins were normal. The proportion of peripheral blood T cells forming spontaneous sheep erythrocyte rosettes and the percentage of B cells forming EAC rosettes by the C3 receptor were normal. The significance of the absence of C3 in our patient is emphasized by the increased number of infections with encapsulated bacteria and the decreased functional biological activities of the C system, important in host defense mechanism(s). Images PMID:1159084

  6. IgG red blood cell autoantibodies in autoimmune hemolytic anemia bind to epitopes on red blood cell membrane band 3 glycoprotein

    SciTech Connect

    Victoria, E.J.; Pierce, S.W.; Branks, M.J.; Masouredis, S.P. )

    1990-01-01

    Red blood cell (RBC) autoantibodies from patients with IgG warm-type autoimmune hemolytic anemia were labeled with iodine 125 and their RBC binding behavior characterized. Epitope-bearing RBC membrane polypeptides were identified after autoantibody immunoprecipitation of labeled membranes and immunoblotting. Immunoaffinity isolation of labeled membrane proteins with 12 different IgG hemolytic autoantibodies with protein A-agarose revealed a major polypeptide at Mr 95 to 110 kd, which coelectrophoresed on sodium dodecylsulfate-polyacrylamide gel electrophoresis with a membrane component isolated with sheep IgG anti-band 3. Immunoprecipitation studies with chymotrypsinized RBCs resulted in the recovery of two labeled membrane polypeptides with molecular weights characteristically resulting from the chymotryptic fragmentation of band 3. Immunoblotting with sheep IgG anti-band 3 of the immunoprecipitated polypeptides confirmed that hemolytic autoantibody binding led to recovery of band 3 or its fragments. Two 125I-labeled IgG hemolytic autoantibodies showed binding behavior consistent with epitope localization on band 3. The labeled RBC autoantibodies bound immunospecifically to all types of human RBC tested, including those of rare Rh type (Rh-null, D--) at a site density of approximately 10(6) per RBC. The 125I-IgG in two labeled autoantibodies was 84% and 92% adsorbable by human and higher nonhuman primate RBCs. Antigen-negative animal RBC bound less than 10%, consistent with immunospecific RBC binding. IgG-1 was the major subclass in five autoantibodies tested; one of six fixed complement; and autoantibody IgG appeared polyclonal by isoelectric focusing. We conclude that IgG eluted from RBCs of patients with autoimmune hemolytic anemia consists predominantly of a single totally RBC-adsorbable antibody population that binds to antigenic determinants on band 3.

  7. Cationic amphiphilic non-hemolytic polyacrylates with superior antibacterial activity.

    PubMed

    Punia, Ashish; He, Edward; Lee, Kevin; Banerjee, Probal; Yang, Nan-Loh

    2014-07-01

    Acrylic copolymers with appropriate compositions of counits having cationic charge with 2-carbon and 6-carbon spacer arms can show superior antibacterial activities with concomitant very low hemolytic effect. These amphiphilic copolymers represent one of the most promising synthetic polymer antibacterial systems reported. PMID:24854366

  8. Successful treatment of neonatal atypical hemolytic uremic syndrome with C5 monoclonal antibody.

    PubMed

    Anastaze Stelle, K; Gonzalez, E; Wilhelm-Bals, A; Michelet, P-R; Korff, C M; Parvex, P

    2016-03-01

    Hemolytic uremic syndrome (HUS) is rare in neonates. We report the case of atypical HUS (aHUS) revealed by neonatal seizures. This 18-day-old baby presented with repeated clonus of the left arm and eye deviation. Four days earlier, she had suffered from gastroenteritis (non-bloody diarrhea and vomiting without fever). Her work-up revealed hemolytic anemia (120 g/L), thrombocytopenia (78 g/L), and impaired renal function (serum creatinine=102 μmol/L) compatible with the diagnosis of HUS. Levels of C3 and C4 in the serum were normal. Shiga-toxin in the stools as well as the IgM and IgG against Escherichia coli O157 were negative. ADAMTS 13 deficiency, inborn error of the cobalamin pathway, deficiency in the H and I protein, and factor H antibodies were excluded and we concluded in aHUS. Genetic screening of the alternative complement pathway was normal. Cerebral magnetic resonance imaging performed after 24 h and 1 week showed restricted diffusion areas with periventricular white matter ischemic-hemorrhagic lesions. Extensive infectious work-up was negative. Upon admission the baby received antiepileptic drugs and 2 days later C5 monoclonal antibody (eculizumab) and two transfusions of packed erythrocytes because the hemoglobin value had dropped to 55 g/L. The platelet value was minimal at 30 g/L. Renal function normalized in 48 h without dialysis and neurological examination was normal in 1 week. She was discharged from the hospital at day 10 with eculizumab perfusions (300 mg) planned every 3 weeks. After 24 months, she was relapse-free and seizure-free, with a normal neurological examination. PMID:26775886

  9. Eculizumab reduces complement activation, inflammation, endothelial damage, thrombosis, and renal injury markers in aHUS

    PubMed Central

    Cofiell, Roxanne; Kukreja, Anjli; Bedard, Krystin; Yan, Yan; Mickle, Angela P.; Ogawa, Masayo; Bedrosian, Camille L.

    2015-01-01

    Atypical hemolytic uremic syndrome (aHUS) is a genetic, life-threatening disease characterized by uncontrolled complement activation, systemic thrombotic microangiopathy (TMA), and vital organ damage. We evaluated the effect of terminal complement blockade with the anti-C5 monoclonal antibody eculizumab on biomarkers of cellular processes involved in TMA in patients with aHUS longitudinally, during up to 1 year of treatment, compared with in healthy volunteers. Biomarker levels were elevated at baseline in most patients, regardless of mutational status, plasma exchange/infusion use, platelet count, or lactate dehydrogenase or haptoglobin levels. Eculizumab reduced terminal complement activation (C5a and sC5b-9) and renal injury markers (clusterin, cystatin-C, β2-microglobulin, and liver fatty acid binding protein-1) to healthy volunteer levels and reduced inflammation (soluble tumor necrosis factor receptor-1), coagulation (prothrombin fragment F1+2 and d-dimer), and endothelial damage (thrombomodulin) markers to near-normal levels. Alternative pathway activation (Ba) and endothelial activation markers (soluble vascular cell adhesion molecule-1) decreased but remained elevated, reflecting ongoing complement activation in aHUS despite complete terminal complement blockade. These results highlight links between terminal complement activation and inflammation, endothelial damage, thrombosis, and renal injury and underscore ongoing risk for systemic TMA and progression to organ damage. Further research regarding underlying complement dysregulation is warranted. This trial was registered at www.clinicaltrials.gov as #NCT01194973. PMID:25833956

  10. Hemolytic activity of dermatophytes species isolated from clinical specimens.

    PubMed

    Aktas, E; Yıgıt, N

    2015-03-01

    Hemolytic activity was recently reported for several pathogenic fungal species, such as Aspergillus, Candida, Trichophyton, Penicillium and Fusarium. Based on a number of mechanistic and characterization studies, several fungal hemolysins have been proposed as virulence factors. Hemolysins lyse red blood cells resulting in the release of iron, an important growth factor for microbes especially during infection. The requirement of iron in fungal growth is necessary for metabolic processes and as a catalyst for various biochemical processes. Expression of a hemolytic protein with capabilities to lyse red blood cells has also been suggested to provide a survival strategy for fungi during opportunistic infections. The aims of this study were to investigate the hemolytic activities of dermatophytes species isolated from patients with dermatophytosis. Hair, skin and nail samples of patients were examined with direct microscopy using potassium hydroxide and cultivated on Mycobiotic agar and Sabouraud's dextrose agar. To determine hemolytic activities of dermatophytes species, they were subcultured on Columbia Agar with 5% sheep blood and incubated for 7-14 days at 25°C in aerobic conditions. Media which displayed hemolysis were further incubated for 1-5 days at 37°C to increase hemolytic activity. In this study, 66 dermatophytes strains were isolated from clinical specimens and were identified by six different species: 43 (65.1%) Trichophyton rubrum, 7 (10.7%) Trichophyton mentagrophytes, 5 (7.6%) Microsporum canis, 5 (7.6%) Trichophyton tonsurans, 4 (6.0%) Epidermophyton floccosum and 2 (3.0%) Trichophyton violaceum. Twenty-one T. rubrum strains showed incomplete (alpha) hemolysis and nine T. rubrum strains showed complete (beta) hemolysis, whereas hemolysis was absent in 13 T. rubrum strains. Four T. mentagrophytes strains showed complete hemolysis and three T. tonsurans strains showed incomplete hemolysis. However, M. canis, E. floccosum and T. violaceum species had

  11. Complement levles in relation to certain antibodies in polytransfused thalassaemic patients.

    PubMed

    Economidou, J; Pathouli, C; Hadziyannis, S; Fostiropoulos, G; Constantoulakis, M

    1976-01-01

    Polytransfused patients are exposed to a variety of antigenic stimuli which may eventually trigger autoimmune reactions. The relation of serum complement to the occurrence of various antibodies has been investigated in a group of 75 polytransfused thalassaemic patients. The incidence of the antibodies studied was as follows: anti-HBs 77%, anti-Gm 64%, rheumatoid factor 31%, antinuclear 13%, anti-smooth muscle 47%. Anti-perietal cell, anti-thyroid and anti-kidney were only rarely found and antimitochondrial antibodies were never detected. Total hemolytic complement was low in 6 and incidentally decreased in 21 patients. A positive correlation was found between low serum complement and presence of rheumatoid factor. The high incidence of anti-smooth muscle antibodies seems to be unrelated to liver disease. PMID:1087502

  12. Red blood cell vesiculation in hereditary hemolytic anemia

    PubMed Central

    Alaarg, Amr; Schiffelers, Raymond M.; van Solinge, Wouter W.; van Wijk, Richard

    2013-01-01

    Hereditary hemolytic anemia encompasses a heterogeneous group of anemias characterized by decreased red blood cell survival because of inherited membrane, enzyme, or hemoglobin disorders. Affected red blood cells are more fragile, less deformable, and more susceptible to shear stress and oxidative damage, and show increased vesiculation. Red blood cells, as essentially all cells, constitutively release phospholipid extracellular vesicles in vivo and in vitro in a process known as vesiculation. These extracellular vesicles comprise a heterogeneous group of vesicles of different sizes and intracellular origins. They are described in literature as exosomes if they originate from multi-vesicular bodies, or as microvesicles when formed by a one-step budding process directly from the plasma membrane. Extracellular vesicles contain a multitude of bioactive molecules that are implicated in intercellular communication and in different biological and pathophysiological processes. Mature red blood cells release in principle only microvesicles. In hereditary hemolytic anemias, the underlying molecular defect affects and determines red blood cell vesiculation, resulting in shedding microvesicles of different compositions and concentrations. Despite extensive research into red blood cell biochemistry and physiology, little is known about red cell deformability and vesiculation in hereditary hemolytic anemias, and the associated pathophysiological role is incompletely assessed. In this review, we discuss recent progress in understanding extracellular vesicles biology, with focus on red blood cell vesiculation. Also, we review recent scientific findings on the molecular defects of hereditary hemolytic anemias, and their correlation with red blood cell deformability and vesiculation. Integrating bio-analytical findings on abnormalities of red blood cells and their microvesicles will be critical for a better understanding of the pathophysiology of hereditary hemolytic anemias. PMID

  13. Impairment of Bone Health in Pediatric Patients with Hemolytic Anemia

    PubMed Central

    Schündeln, Michael M.; Goretzki, Sarah C.; Hauffa, Pia K.; Wieland, Regina; Bauer, Jens; Baeder, Lena; Eggert, Angelika; Hauffa, Berthold P.; Grasemann, Corinna

    2014-01-01

    Introduction Sickle cell anemia and thalassemia result in impaired bone health in both adults and youths. Children with other types of chronic hemolytic anemia may also display impaired bone health. Study Design To assess bone health in pediatric patients with chronic hemolytic anemia, a cross-sectional study was conducted involving 45 patients with different forms of hemolytic anemia (i.e., 17 homozygous sickle cell disease and 14 hereditary spherocytosis patients). Biochemical, radiographic and anamnestic parameters of bone health were assessed. Results Vitamin D deficiency with 25 OH-vitamin D serum levels below 20 ng/ml was a common finding (80.5%) in this cohort. Bone pain was present in 31% of patients. Analysis of RANKL, osteoprotegerin (OPG) and osteocalcin levels indicated an alteration in bone modeling with significantly elevated RANKL/OPG ratios (control: 0.08+0.07; patients: 0.26+0.2, P = 0.0007). Osteocalcin levels were found to be lower in patients compared with healthy controls (68.5+39.0 ng/ml vs. 118.0+36.6 ng/ml, P = 0.0001). Multiple stepwise regression analysis revealed a significant (P<0.025) influence of LDH (partial r2 = 0.29), diagnosis of hemolytic anemia (partial r2 = 0.05) and age (partial r2 = 0.03) on osteocalcin levels. Patients with homozygous sickle cell anemia were more frequently and more severely affected by impaired bone health than patients with hereditary spherocytosis. Conclusion Bone health is impaired in pediatric patients with hemolytic anemia. In addition to endocrine alterations, an imbalance in the RANKL/OPG system and low levels of osteocalcin may contribute to this impairment. PMID:25299063

  14. Novel Evasion Mechanisms of the Classical Complement Pathway.

    PubMed

    Garcia, Brandon L; Zwarthoff, Seline A; Rooijakkers, Suzan H M; Geisbrecht, Brian V

    2016-09-15

    Complement is a network of soluble and cell surface-associated proteins that gives rise to a self-amplifying, yet tightly regulated system with fundamental roles in immune surveillance and clearance. Complement becomes activated on the surface of nonself cells by one of three initiating mechanisms known as the classical, lectin, and alternative pathways. Evasion of complement function is a hallmark of invasive pathogens and hematophagous organisms. Although many complement-inhibition strategies hinge on hijacking activities of endogenous complement regulatory proteins, an increasing number of uniquely evolved evasion molecules have been discovered over the past decade. In this review, we focus on several recent investigations that revealed mechanistically distinct inhibitors of the classical pathway. Because the classical pathway is an important and specific mediator of various autoimmune and inflammatory disorders, in-depth knowledge of novel evasion mechanisms could direct future development of therapeutic anti-inflammatory molecules. PMID:27591336

  15. Complement System in Lung Disease

    PubMed Central

    Pandya, Pankita H.

    2014-01-01

    In addition to its established contribution to innate immunity, recent studies have suggested novel roles for the complement system in the development of various lung diseases. Several studies have demonstrated that complement may serve as a key link between innate and adaptive immunity in a variety of pulmonary conditions. However, the specific contributions of complement to lung diseases based on innate and adaptive immunity are just beginning to emerge. Elucidating the role of complement-mediated immune regulation in these diseases will help to identify new targets for therapeutic interventions. PMID:24901241

  16. Genetics and Outcome of Atypical Hemolytic Uremic Syndrome: A Nationwide French Series Comparing Children and Adults

    PubMed Central

    Fremeaux-Bacchi, Véronique; Fakhouri, Fadi; Garnier, Arnaud; Bienaimé, Frank; Dragon-Durey, Marie-Agnès; Ngo, Stéphanie; Moulin, Bruno; Servais, Aude; Provot, François; Rostaing, Lionel; Burtey, Stéphane; Niaudet, Patrick; Deschênes, Georges; Lebranchu, Yvon; Zuber, Julien; Loirat, Chantal

    2013-01-01

    Summary Background and objectives Atypical hemolytic uremic syndrome (aHUS) is a rare complement-mediated kidney disease that was first recognized in children but also affects adults. This study assessed the disease presentation and outcome in a nationwide cohort of patients with aHUS according to the age at onset and the underlying complement abnormalities. Design, setting, participants, & measurements A total of 214 patients with aHUS were enrolled between 2000 and 2008 and screened for mutations in the six susceptibility factors for aHUS and for anti–factor H antibodies. Results Onset of aHUS occurred as frequently during adulthood (58.4%) as during childhood (41.6%). The percentages of patients who developed the disease were 23%, 40%, 70%, and 98% by age 2, 18, 40, and 60 years, respectively. Mortality was higher in children than in adults (6.7% versus 0.8% at 1 year) (P=0.02), but progression to ESRD after the first aHUS episode was more frequent in adults (46% versus 16%; P<0.001). Sixty-one percent of patients had mutations in their complement genes. The renal outcome was not significantly different in adults regardless of genetic background. Only membrane cofactor protein (MCP) and undetermined aHUS were less severe in children than adults. The frequency of relapse after 1 year was 92% in children with MCP-associated HUS and approximately 30% in all other subgroups. Conclusion Mortality rate was higher in children than adults with aHUS, but renal prognosis was worse in adults than children. In children, the prognosis strongly depends on the genetic background. PMID:23307876

  17. Case report: Benefits and challenges of long-term eculizumab in atypical hemolytic uremic syndrome.

    PubMed

    Cullinan, Noelle; Gorman, Kathleen Mary; Riordan, Michael; Waldron, Mary; Goodship, Timothy H J; Awan, Atif

    2015-06-01

    Atypical hemolytic uremic syndrome (aHUS) is caused by dysregulation of the complement system, leading to complement overactivation. A humanized anti-C5 monoclonal antibody, eculizumab, has been available for the treatment of aHUS since 2011. The long-term safety and efficacy of this novel drug in the pediatric population remain under review. We present a child with a hybrid CFH/CFHR3 gene who, having had multiple disease relapses despite optimal treatment with plasma exchange, commenced eculizumab therapy in August 2010. She remains relapse free in follow-up at 52 months, and treatment has been well tolerated. The risk of meningococcal disease during this treatment is recognized. Despite vaccination against meningococcal disease and appropriate antibiotic prophylaxis, our patient developed meningococcal bacteremia 30 months into treatment. She presented with nonspecific symptoms but recovered without sequelae with appropriate treatment. We recommend that children be vaccinated against invasive meningococcal infection before beginning eculizumab therapy and take appropriate antibiotic prophylaxis during treatment, and we suggest that vaccine responses should be checked and followed annually. Clinicians need to maintain a high index of suspicion for invasive meningococcal disease. Neither vaccination nor antibiotic prophylaxis provides complete protection in patients on eculizumab therapy. The appropriate dosage of eculizumab needed to achieve remission in aHUS in the pediatric population is unknown. Having achieved remission in our patient, we monitor eculizumab and CH50 levels to evaluate ongoing blockade of the terminal complement cascade. Such information may help guide dosing intervals in the future. PMID:25941307

  18. Atypical Hemolytic Uremic Syndrome: Differential Diagnosis from TTP/HUS and Management.

    PubMed

    Yenerel, Mustafa N

    2014-09-01

    Atypical hemolytic uremic syndrome (aHUS) is a rare form of thrombotic microangiopathy (TMA). It has an unfavorable outcome with death rates as high as 25% during the acute phase and up to 50% of cases progressing to end-stage renal failure. Uncontrolled complement activation through the alternative pathway is thought to be the main underlying pathopysiology of aHUS and corresponds to all the deleterious findings of the disease. Thrombotic thrombocytopenic purpura (TTP) and Shiga toxin-associated HUS are the 2 other important TMA diseases. Although differentiating HUS from TTP is relatively easy in children with a preceding diarrheal illness or invasive S. pneumoniae, differentiating aHUS from TTP or other microangiopathic disorders can present a major diagnostic challenge in adults. ADAMTS13 analysis is currently the most informative diagnostic test for differentiating TTP, congenital TTP, and aHUS. Today empiric plasma therapy still is recommended by expert opinion to be used as early as possible in any patient with symptoms of aHUS. The overall treatment goal remains restoration of a physiological balance between activation and control of the alternative complement pathway. So it is a reasonable approach to block the terminal complement complex with eculizumab in order to prevent further organ injury and increase the likelihood organ recovery. Persistence of hemolysis or lack of improvement of renal function after 3-5 daily plasmaphereses have to be regarded as the major criteria for uncontrolled TMA even if platelet count has normalized and as an indication to switch the treatment to eculizumab. Eculizumab has changed the future perspectives of patients with aHUS and both the FDA and the EMA have approved it as life-long treatment. However, there are still some unresolved issues about the follow-up such as the optimal duration of eculizumab treatment and whether it can be stopped or how to stop the therapy. PMID:25319590

  19. Complementing T-cell Function: An Inhibitory Role of the Complement System in T-cell-Mediated Antitumor Immunity.

    PubMed

    Peng, Weiyi; McKenzie, Jodi A; Hwu, Patrick

    2016-09-01

    New data from Wang and colleagues show that complement C3 suppresses the function of CD8(+) tumor-infiltrating T cells by inhibiting IL10 production, and targeting the complement receptors C3aR and C5aR enhances the antitumor activity of immune checkpoint blockade. Their results not only define a new role of complement receptors as T-cell coinhibitory receptors, but also are useful in the development of novel strategies to improve the effectiveness of cancer immunotherapy. Cancer Discov; 6(9); 953-5. ©2016 AACR.See related article by Wang et al., p. 1022. PMID:27587467

  20. Atypical hemolytic uremic syndrome: from diagnosis to treatment.

    PubMed

    Franchini, Massimo

    2015-10-01

    Thrombotic microangiopathy (TMA) is a relatively rare condition but a medical urgency requiring immediate intervention to avoid irreversible organ damage or death. Symptoms on presentation include microangiopathic haemolytic anaemia, thrombocytopenia and organ damage. The most frequent direct causes of TMA are thrombotic thrombocytopenic purpura (TTP) and haemolytic uremic syndrome (HUS). The most common form of HUS is related to Shiga toxin producing Escherichia coli (STEC) infection while approximately 10% of cases are due to dysregulation of the complement pathway (atypical haemolytic uremic syndrome, aHUS). Optimal treatment regimens differ depending on the underlying cause; however, differential diagnosis may be difficult. The most accurate method of diagnosis is based on exclusion and should consider, beyond the symptoms common to TMA, ADAMTS13 activity levels and STEC infection status. For the management of TTP, plasma exchange (PE) is the most important acute intervention and is associated with lower mortality and better outcomes than plasma infusion. In most patients with STEC-HUS, the course of disease is self-limiting although management of acute kidney injury is often required. Until recently, the management of aHUS consisted of early and intensive PE, although this was mostly ineffective in protecting from subsequent organ damage. Eculizumab, an inhibitor of the alternative complement pathway, produces a rapid and sustained inhibition of the TMA process, with significant improvements in long-term clinical outcomes. Due to the significant improvement achieved, eculizumab has subsequently been approved as first-line therapy when an unequivocal diagnosis of aHUS has been made. PMID:25803082

  1. Anticariogenic and Hemolytic Activity of Selected Seed Protein Extracts In vitro conditions

    PubMed Central

    Ishnava, Kalpesh B; Shah, Pankit P.

    2014-01-01

    Objective: This study aimed to assess the anticariogenic and hemolytic activity of crude plant seed protein extracts against tooth decaying bacteria. Materials and Methods: The proteins from seeds of 12 different plants were extracted and used for antimicrobial assay against six different organisms. The extraction was carried out in 10mM of sodium phosphate buffer (pH 7.0). Protein concentrations were determined as described by Bradford method. Anticariogenic activity was studied by agar well diffusion method and Minimum Inhibitory Concentration (MIC) was evaluated by the two-fold serial broth dilution method. Hemolytic activity, treatment of proteinase K and Kinetic study in Mimusops elengi crude seed protein extract. Results: The anticariogenic assay demonstrated the activity of Mimusops elengi against Staphylococcus aureus and Streptococcus pyogenes. A minor activity of Glycine wightii against Streptococcus mutans was also found. The protein content of Mimusops elengi seed protein extract was 5.84mg/ml. The MIC values for Staphylococcus aureus and Streptococcus pyogenes against Mimusops elengi seed protein extract were 364.36μg/ml and 182.19μg/ml, respectively. Kinetic study further elucidated the mode of inhibition in the presence of the Mimusops elengi plant seed protein with respect to time. The concentration of crude extract which gave 50% hemolysis compared to Triton X-100 treatment (HC50) value was 1.58 mg/ml; which is more than five times larger than that of the MIC. Treatment with proteinase K of the Mimusops elengi seed protein resulted in absence of the inhibition zone; which clearly indicates that the activity was only due to protein. Conclusion: Our results showed the prominence of Mimusops elengi plant seed protein extract as an effective herbal medication against tooth decaying bacteria. PMID:25628685

  2. Bimolecular fluorescence complementation.

    PubMed

    Wong, Katy A; O'Bryan, John P

    2011-01-01

    Defining the subcellular distribution of signaling complexes is imperative to understanding the output from that complex. Conventional methods such as immunoprecipitation do not provide information on the spatial localization of complexes. In contrast, BiFC monitors the interaction and subcellular compartmentalization of protein complexes. In this method, a fluororescent protein is split into amino- and carboxy-terminal non-fluorescent fragments which are then fused to two proteins of interest. Interaction of the proteins results in reconstitution of the fluorophore (Figure 1). A limitation of BiFC is that once the fragmented fluorophore is reconstituted the complex is irreversible. This limitation is advantageous in detecting transient or weak interactions, but precludes a kinetic analysis of complex dynamics. An additional caveat is that the reconstituted flourophore requires 30min to mature and fluoresce, again precluding the observation of real time interactions. BiFC is a specific example of the protein fragment complementation assay (PCA) which employs reporter proteins such as green fluorescent protein variants (BiFC), dihydrofolate reductase, b-lactamase, and luciferase to measure protein:protein interactions. Alternative methods to study protein:protein interactions in cells include fluorescence co-localization and Förster resonance energy transfer (FRET). For co-localization, two proteins are individually tagged either directly with a fluorophore or by indirect immunofluorescence. However, this approach leads to high background of non-interacting proteins making it difficult to interpret co-localization data. In addition, due to the limits of resolution of confocal microscopy, two proteins may appear co-localized without necessarily interacting. With BiFC, fluorescence is only observed when the two proteins of interest interact. FRET is another excellent method for studying protein:protein interactions, but can be technically challenging. FRET

  3. Protective responses to sublytic complement in the retinal pigment epithelium.

    PubMed

    Tan, Li Xuan; Toops, Kimberly A; Lakkaraju, Aparna

    2016-08-01

    The retinal pigment epithelium (RPE) is a key site of injury in inherited and age-related macular degenerations. Abnormal activation of the complement system is a feature of these blinding diseases, yet how the RPE combats complement attack is poorly understood. The complement cascade terminates in the cell-surface assembly of membrane attack complexes (MACs), which promote inflammation by causing aberrant signal transduction. Here, we investigated mechanisms crucial for limiting MAC assembly and preserving cellular integrity in the RPE and asked how these are compromised in models of macular degeneration. Using polarized primary RPE and the pigmented Abca4(-/-) Stargardt disease mouse model, we provide evidence for two protective responses occurring within minutes of complement attack, which are essential for maintaining mitochondrial health in the RPE. First, accelerated recycling of the membrane-bound complement regulator CD59 to the RPE cell surface inhibits MAC formation. Second, fusion of lysosomes with the RPE plasma membrane immediately after complement attack limits sustained elevations in intracellular calcium and prevents mitochondrial injury. Cholesterol accumulation in the RPE, induced by vitamin A dimers or oxidized LDL, inhibits these defense mechanisms by activating acid sphingomyelinase (ASMase), which increases tubulin acetylation and derails organelle traffic. Defective CD59 recycling and lysosome exocytosis after complement attack lead to mitochondrial fragmentation and oxidative stress in the RPE. Drugs that stimulate cholesterol efflux or inhibit ASMase restore both these critical safeguards in the RPE and avert complement-induced mitochondrial injury in vitro and in Abca4(-/-) mice, indicating that they could be effective therapeutic approaches for macular degenerations. PMID:27432952

  4. Hemolytic C-type lectin CEL-III from sea cucumber expressed in transgenic mosquitoes impairs malaria parasite development.

    PubMed

    Yoshida, Shigeto; Shimada, Yohei; Kondoh, Daisuke; Kouzuma, Yoshiaki; Ghosh, Anil K; Jacobs-Lorena, Marcelo; Sinden, Robert E

    2007-12-01

    The midgut environment of anopheline mosquitoes plays an important role in the development of the malaria parasite. Using genetic manipulation of anopheline mosquitoes to change the environment in the mosquito midgut may inhibit development of the malaria parasite, thus blocking malaria transmission. Here we generate transgenic Anopheles stephensi mosquitoes that express the C-type lectin CEL-III from the sea cucumber, Cucumaria echinata, in a midgut-specific manner. CEL-III has strong and rapid hemolytic activity toward human and rat erythrocytes in the presence of serum. Importantly, CEL-III binds to ookinetes, leading to strong inhibition of ookinete formation in vitro with an IC(50) of 15 nM. Thus, CEL-III exhibits not only hemolytic activity but also cytotoxicity toward ookinetes. In these transgenic mosquitoes, sporogonic development of Plasmodium berghei is severely impaired. Moderate, but significant inhibition was found against Plasmodium falciparum. To our knowledge, this is the first demonstration of stably engineered anophelines that affect the Plasmodium transmission dynamics of human malaria. Although our laboratory-based research does not have immediate applications to block natural malaria transmission, these findings have significant implications for the generation of refractory mosquitoes to all species of human Plasmodium and elucidation of mosquito-parasite interactions. PMID:18159942

  5. Acute Progression of Adult-Onset Atypical Hemolytic-Uremic Syndrome due to CFH Mutation: A Case Report

    PubMed Central

    Sikorska, Dorota; Hoppe, Krzysztof; Schwermer, Krzysztof; Oko, Andrzej

    2013-01-01

    Atypical hemolytic-uremic syndrome (aHUS), unlike typical HUS, is not due to bacteria but rather to an idiopathic or genetic cause that promotes dysregulation of the alternative complement pathway. It leads to hemolytic anemia, thrombocytopenia, and renal impairment. Although aHUS secondary to a genetic mutation is relatively rare, when occurring due to a mutation in Factor H (CFH), it usually presents with younger onset and has a more severe course, which in the majority ends with end-stage renal failure. Paradoxically to most available data, our case features acute aHUS due to a CFH mutation with late onset (38-year-old) and rapid progression to end-stage renal disease. Due to current data indicating a high risk of graft failure in such patients, the diagnosis of aHUS secondary to a genetic cause has disqualified our patient from a living (family) donor renal transplantation and left her with no other option but to begin permanent renal replacement therapy. PMID:24558625

  6. Adult patent Ductus Arteriosus complicated by endocarditis and hemolytic anemia

    PubMed Central

    Sabzi, Feridoun

    2015-01-01

    An adult with a large patent ductus arteriosus may present with fatigue, dyspnea or palpitations or in rare presentation with endocarditis. The case illustrated unique role of vegetation of endocarditis in hemolytic anemia in adult with patent ductus arteriosus (PDA). Despite treatment of endocarditis with complete course of appropriate antibiotic therapy and normality of C- reactive protein, erythrocyte sedimentation rate and leukocytosis and wellness of general condition, transthoracic echocardiography revealed large vegetation in PDA lumen, surgical closure of PDA completely relieved hemolysis, and fragmented red cell disappeared from peripheral blood smear. The 3-month follow-up revealed complete occlusion of PDA and abolishment of hemolytic anemia confirmed by clinical and laboratory examination. PMID:26309344

  7. Autoimmune Hemolytic Anemia and Hodgkin's Disease: An Unusual Pediatric Association

    PubMed Central

    Gomes, Maria Miguel; Oliva, Tereza; Pinto, Armando

    2016-01-01

    Autoimmune hemolytic anemia (AIHA) is a recognized complication of lymphoproliferative disorders. AIHA associated with Hodgkin's disease (HD) is uncommon especially in the pediatric population. The diagnosis of AIHA is usually associated with HD at the time of initial presentation or during the course of disease, but it could precede it by years to months. In adults the association of AIHA and HD is more frequent in advanced stages and in the nodular sclerosis and mixed cellularity type HD. Warm immune hemolytic anemia is mainly controlled with steroids and chemotherapy. We report a case of a pediatric patient with direct antiglobulin positive test at the diagnosis of a late relapse of stage III B mixed cellularity type HD. PMID:26904342

  8. [Occurrence and drug-resistance of beta-hemolytic streptococci].

    PubMed

    Mikołajczyk, Dorota; Budzyńska, Anna; Kaczmarek, Agnieszka; Gospodarek, Eugenia

    2007-01-01

    The aim of this study was the analysis of drug-resistance and frequency appearance of beta-hemolytic streptococci strains which were isolated in 2003-2005 in the University Hospital at the L. Rydygier Collegium Medicum in Bydgoszcz University of Nicolaus Copernicus in Toruń. Among investigeted beta-hemolytic streptococci the most frequency isolated species was S. agalactiae. All isolates examined in our study were susceptible to penicillin, the higest rate of resistance was found for tetracycline. The rates of resistence to macrolide-lincosamide-streptogramin B (phenotyp MLS(B)) were as follows: S. agalactiae (18.7%), S. pyogenes (10.1%), group G streptococci (10.6%) and group C streptococci (8.0%). In our study we presented also a special case patient from which in investigeted period S. agalactiae was isolated twenty eight times. For ten chromosomal DNA isolated from this patient three different PFGE profiles were obtained. PMID:18416122

  9. Adult patent ductus arteriosus complicated by endocarditis and hemolytic anemia.

    PubMed

    Sabzi, Feridoun; Faraji, Reza

    2015-01-01

    An adult with a large patent ductus arteriosus may present with fatigue, dyspnea or palpitations or in rare presentation with endocarditis. The case illustrated unique role of vegetation of endocarditis in hemolytic anemia in adult with patent ductus arteriosus (PDA). Despite treatment of endocarditis with complete course of appropriate antibiotic therapy and normality of C- reactive protein, erythrocyte sedimentation rate and leukocytosis and wellness of general condition, transthoracic echocardiography revealed large vegetation in PDA lumen, surgical closure of PDA completely relieved hemolysis, and fragmented red cell disappeared from peripheral blood smear. The 3-month follow-up revealed complete occlusion of PDA and abolishment of hemolytic anemia confirmed by clinical and laboratory examination. PMID:26309344

  10. The Complement System in Schizophrenia

    PubMed Central

    Mayilyan, Karine R.; Weinberger, Daniel R.; Sim, Robert B.

    2009-01-01

    summary Several lines of evidence suggest that immunological factors contribute to schizophrenia. Since 1989, the role of complement, a major effector of innate immunity and an adjuvant of adaptive immunity, has been explored in schizophrenia. Increased activity of C1, C3, C4 complement components in schizophrenia has been reported by two or more groups. Two studies on different subject cohorts showed increased MBL-MASP-2 activity in patients versus controls. More then one report indicated a significant high frequency of FB*F allotype and low prevalence of the FS phenotype of complement factor B in schizophrenia. From the data reported, it is likely that the disorder is accompanied by alterations of the complement classical and lectin pathways, which undergo dynamic changes, depending on the illness course and the state of neuro-immune crosstalk. Recent findings, implicating complement in neurogenesis, synapse remodeling and pruning during brain development, suggest a reexamination of the potential role of complement in neurodevelopmental processes contributing to schizophrenia susceptibility. It is plausible that the multicomponent complement system has more than one dimensional association with schizophrenia susceptibility, pathopsychology and illness course, understanding of which will bring a new perspective for possible immunomodulation and immunocorrection of the disease. PMID:18560619

  11. Complement-activating ability of leucocytes from patients with complement factor I deficiency.

    PubMed Central

    Marquart, H V; Rasmussen, J M; Leslie, R G

    1997-01-01

    Previous studies from this laboratory have shown that normal peripheral blood B cells are capable of activating complement via the alternative pathway (AP), that the activation is associated with complement receptor type 2 (CR2) expression, and that erythrocytes at normal blood levels partially inhibit the activation. The purpose of the present study was to investigate whether factor I (FI) deficiency, which leads to continued formation of the AP convertase (C3bBb) resulting in the consumption of factor B and C3 and large scale generation of C3b fragments, affects the phenotype and/or function of the patients' B cells. Using flow cytometry, peripheral blood leucocytes (PBL) from two FI-deficient patients were investigated for expression of complement receptors and complement regulatory proteins, in vivo-deposited C3 fragments and in vitro complement-activating ability. CR1 levels on B cells were significantly lower in FI-deficient patients than in normal individuals, whereas CR2 levels were found to be reduced, although not to a significant extent. CR1 levels on monocytes and polymorphonuclear leucocytes (PMN) were found to be normal or slightly raised. All leucocyte subpopulations were found to be covered in vivo with C3b fragments. AP activation on B cells from FI-deficient patients in homologous serum was significantly reduced compared with that for normal individuals, whereas no in vitro activation was seen in autologous serum. In addition, the in vivo-bound C3b fragments were degraded to C3d,g when the patients' PBL were incubated in homologous serum containing EDTA. Finally, the patients, erythrocytes failed to exert any inhibition on AP activation in homologous serum. PMID:9301541

  12. A Web Server and Mobile App for Computing Hemolytic Potency of Peptides

    NASA Astrophysics Data System (ADS)

    Chaudhary, Kumardeep; Kumar, Ritesh; Singh, Sandeep; Tuknait, Abhishek; Gautam, Ankur; Mathur, Deepika; Anand, Priya; Varshney, Grish C.; Raghava, Gajendra P. S.

    2016-03-01

    Numerous therapeutic peptides do not enter the clinical trials just because of their high hemolytic activity. Recently, we developed a database, Hemolytik, for maintaining experimentally validated hemolytic and non-hemolytic peptides. The present study describes a web server and mobile app developed for predicting, and screening of peptides having hemolytic potency. Firstly, we generated a dataset HemoPI-1 that contains 552 hemolytic peptides extracted from Hemolytik database and 552 random non-hemolytic peptides (from Swiss-Prot). The sequence analysis of these peptides revealed that certain residues (e.g., L, K, F, W) and motifs (e.g., “FKK”, “LKL”, “KKLL”, “KWK”, “VLK”, “CYCR”, “CRR”, “RFC”, “RRR”, “LKKL”) are more abundant in hemolytic peptides. Therefore, we developed models for discriminating hemolytic and non-hemolytic peptides using various machine learning techniques and achieved more than 95% accuracy. We also developed models for discriminating peptides having high and low hemolytic potential on different datasets called HemoPI-2 and HemoPI-3. In order to serve the scientific community, we developed a web server, mobile app and JAVA-based standalone software (http://crdd.osdd.net/raghava/hemopi/).

  13. A Web Server and Mobile App for Computing Hemolytic Potency of Peptides

    PubMed Central

    Chaudhary, Kumardeep; Kumar, Ritesh; Singh, Sandeep; Tuknait, Abhishek; Gautam, Ankur; Mathur, Deepika; Anand, Priya; Varshney, Grish C.; Raghava, Gajendra P. S.

    2016-01-01

    Numerous therapeutic peptides do not enter the clinical trials just because of their high hemolytic activity. Recently, we developed a database, Hemolytik, for maintaining experimentally validated hemolytic and non-hemolytic peptides. The present study describes a web server and mobile app developed for predicting, and screening of peptides having hemolytic potency. Firstly, we generated a dataset HemoPI-1 that contains 552 hemolytic peptides extracted from Hemolytik database and 552 random non-hemolytic peptides (from Swiss-Prot). The sequence analysis of these peptides revealed that certain residues (e.g., L, K, F, W) and motifs (e.g., “FKK”, “LKL”, “KKLL”, “KWK”, “VLK”, “CYCR”, “CRR”, “RFC”, “RRR”, “LKKL”) are more abundant in hemolytic peptides. Therefore, we developed models for discriminating hemolytic and non-hemolytic peptides using various machine learning techniques and achieved more than 95% accuracy. We also developed models for discriminating peptides having high and low hemolytic potential on different datasets called HemoPI-2 and HemoPI-3. In order to serve the scientific community, we developed a web server, mobile app and JAVA-based standalone software (http://crdd.osdd.net/raghava/hemopi/). PMID:26953092

  14. A Web Server and Mobile App for Computing Hemolytic Potency of Peptides.

    PubMed

    Chaudhary, Kumardeep; Kumar, Ritesh; Singh, Sandeep; Tuknait, Abhishek; Gautam, Ankur; Mathur, Deepika; Anand, Priya; Varshney, Grish C; Raghava, Gajendra P S

    2016-01-01

    Numerous therapeutic peptides do not enter the clinical trials just because of their high hemolytic activity. Recently, we developed a database, Hemolytik, for maintaining experimentally validated hemolytic and non-hemolytic peptides. The present study describes a web server and mobile app developed for predicting, and screening of peptides having hemolytic potency. Firstly, we generated a dataset HemoPI-1 that contains 552 hemolytic peptides extracted from Hemolytik database and 552 random non-hemolytic peptides (from Swiss-Prot). The sequence analysis of these peptides revealed that certain residues (e.g., L, K, F, W) and motifs (e.g., "FKK", "LKL", "KKLL", "KWK", "VLK", "CYCR", "CRR", "RFC", "RRR", "LKKL") are more abundant in hemolytic peptides. Therefore, we developed models for discriminating hemolytic and non-hemolytic peptides using various machine learning techniques and achieved more than 95% accuracy. We also developed models for discriminating peptides having high and low hemolytic potential on different datasets called HemoPI-2 and HemoPI-3. In order to serve the scientific community, we developed a web server, mobile app and JAVA-based standalone software (http://crdd.osdd.net/raghava/hemopi/). PMID:26953092

  15. Detection of hemolytic Listeria monocytogenes by using DNA colony hybridization

    SciTech Connect

    Datta, A.R.; Wentz, B.A.; Hill, W.E.

    1987-09-01

    A fragment of about 500 base pairs of the beta-hemolysin gene from Listeria monocytogenes was used to screen different bacterial strains by DNA colony hybridization. The cells in the colonies were lysed by microwaves in the presence of sodium hydroxide. Of 52 different strains of Listeria species screened, only the DNA from beta-hemolytic (CAMP-positive) strains of L. monocytogenes hybridized with this probe.

  16. Evaluation of Neonatal Hemolytic Jaundice: Clinical and Laboratory Parameters

    PubMed Central

    Cherepnalkovski, Anet Papazovska; Krzelj, Vjekoslav; Zafirovska-Ivanovska, Beti; Gruev, Todor; Markic, Josko; Aluloska, Natasa; Zdraveska, Nikolina; Piperkovska, Katica

    2015-01-01

    BACKGROUND: Neonatal jaundice that occurs in ABO or Rhesus issoimunisation has been recognized as one of the major risk factors for development of severe hyperbilirubinemia and bilirubin neurotoxicity. AIM: Aim of our study was to investigate clinical and laboratory parameters associated with hemolytic jaundice due to Rh and ABO incompatibility and compare results with the group of unspecific jaundice. MATERIAL AND METHODS: One hundred sixty seven (167) neonatal hyperbilirubinemia cases were included in the study, 24.6% of which presented with ABO/Rhesus type hemolytic jaundice, and the rest with unspecific jaundice. Evaluation included: blood count, reticulocites, serum bilirubin, aminotransferases, blood grouping, and Coombs test, also the day of bilirubin peak, duration of the hyperbilirubinemia, and additional bilirubin measurements. RESULTS: We showed significantly lower mean values of hemoglobin, erythrocytes and hematocrit and significantly higher values of reticulocytes in the group of ABO/Rh incompatibility compared to the group of jaundice of unspecific etiology; also an earlier presentation and a higher-grade jaundice in this group. CONCLUSIONS: The laboratory profile in ABO/Rh isoimmunisation cases depicts hemolytic mechanism of jaundice. These cases carry a significant risk for early and severe hyperbilirubinemia and are eligible for neurodevelopmental follow-up. Hematological parameters and blood grouping are simple diagnostic methods that assist the etiological diagnosis of neonatal hyperbilirubinemia. PMID:27275310

  17. Hemolytic venoms from marine cnidarian jellyfish – an overview

    PubMed Central

    Mariottini, Gian Luigi

    2014-01-01

    Cnidarian jellyfish are viewed as an emergent problem in several coastal zones throughout the world. Recurrent outbreaks pose a serious threat to tourists and bathers, as well as to sea-workers, involving health and economical aspects. As a rule, cnidarian stinging as a consequence of nematocyst firing induces merely local symptoms but cardiovascular or neurological complications can also occur. Hemolysis is a frequent effect of cnidarian stinging; this dangerous condition is known to be caused by several venoms and can sometimes be lethal. At present, the bulk of data concerning hemolytic cnidarian venoms comes from the study of benthic species, such as sea anemones and soft corals, but hemolytic factors were found in venoms of several siphonophore, cubozoan and scyphozoan jellyfish, which are mainly involved in the envenomation of bathers and sea-workers. Therefore, the aim of this paper is to review the scientific literature concerning the hemolytic venoms from cnidarian jellyfish taking into consideration their importance in human pathology as well as health implications and possible therapeutic measures. PMID:25386336

  18. Hemolytic-Uremic Syndrome—An Outbreak in Sacramento, California

    PubMed Central

    Rogers, Martha F.; Schonberger, Lawrence B.; Budnick, Lawrence D.; Hurwitz, Eugene S.; Hatch, Milford H.; Gary, G. William; Bopp, Cheryl A.; Kirson, Ian; Karmali, Mohamed A.; Layne, Robert

    1986-01-01

    Between July and November 1982, 14 cases of the hemolytic-uremic syndrome occurred in the Sacramento, California, metropolitan area; 9 of the 14 patients lived within a 7.5-mile radius in northeast Sacramento, 10 were female, 12 were white non-Hispanic and 13 were children with a mean age of 3.6 years. Of the 14 patients, 13 were admitted to hospital; 7 required peritoneal dialysis. The 14th child, a 3-month-old white female infant, was found dead in her crib and had renal histopathologic findings consistent with the hemolytic-uremic syndrome. Of the 13 nonfatal cases, 12 patients had diarrhea before being admitted to hospital. A case-control study involving 11 cases and 22 controls did not show any significant differences in exposure to a variety of possible risk factors including restaurants, specific foods and water supply. Stool specimens were negative for enteric bacterial pathogens by culture and for viruses by tissue culture assay, suckling mouse inoculation and immune electron microscopy; no serologic evidence was found for infection due to enteroviruses, respiratory viruses or arenaviruses. Two of four children tested, however, showed serologic evidence of infection by Vero-cytotoxin-producing Escherichia coli. These 14 cases represent one of the largest reported outbreaks of the hemolytic-uremic syndrome in the United States. ImagesFigure 1. PMID:3953085

  19. Hemolytic disease of the newborn due to anti-U.

    PubMed

    Novaretti, Marcia Cristina Zago; Jens, Eduardo; Pagliarini, Thiago; Bonif cio, Silvia Le o; Dorlhiac-Llacer, Pedro Enrique; Chamone Dd, Dalton de Alencar Fischer

    2003-01-01

    Anti-U is a rare red blood cell alloantibody that has been found exclusively in blacks. It can cause hemolytic disease of the newborn and hemolytic transfusion reactions. We describe the case of a female newborn presenting a strongly positive direct antiglobulin test due to an IgG antibody in cord blood. Anti-U was recovered from cord blood using acid eluate technique. Her mother presented positive screening of antibodies with anti-U identified at delivery. It was of IgG1 and IgG3 subclasses and showed a titer of 32. Monocyte monolayer assay showed moderate interaction of Fc receptors with maternal serum with a positive result (3.1%). The newborn was treated only with 48 hours of phototherapy for mild hemolytic disease. She recovered well and was discharged on the 4th day of life. We conclude that whenever an antibody against a high frequency erythrocyte antigen is identified in brown and black pregnant women, anti-U must be investigated. PMID:14762491

  20. The cholesterol-dependent cytolysins pneumolysin and streptolysin O require binding to red blood cell glycans for hemolytic activity

    PubMed Central

    Shewell, Lucy K.; Harvey, Richard M.; Higgins, Melanie A.; Day, Christopher J.; Hartley-Tassell, Lauren E.; Chen, Austen Y.; Gillen, Christine M.; James, David B. A.; Alonzo, Francis; Torres, Victor J.; Walker, Mark J.; Paton, Adrienne W.; Paton, James C.; Jennings, Michael P.

    2014-01-01

    The cholesterol-dependent cytolysin (CDC) pneumolysin (Ply) is a key virulence factor of Streptococcus pneumoniae. Membrane cholesterol is required for the cytolytic activity of this toxin, but it is not clear whether cholesterol is the only cellular receptor. Analysis of Ply binding to a glycan microarray revealed that Ply has lectin activity and binds glycans, including the Lewis histo-blood group antigens. Surface plasmon resonance analysis showed that Ply has the highest affinity for the sialyl LewisX (sLeX) structure, with a Kd of 1.88 × 10−5 M. Ply hemolytic activity against human RBCs showed dose-dependent inhibition by sLeX. Flow cytometric analysis and Western blots showed that blocking binding of Ply to the sLeX glycolipid on RBCs prevents deposition of the toxin in the membrane. The lectin domain responsible for sLeX binding is in domain 4 of Ply, which contains candidate carbohydrate-binding sites. Mutagenesis of these predicted carbohydrate-binding residues of Ply resulted in a decrease in hemolytic activity and a reduced affinity for sLeX. This study reveals that this archetypal CDC requires interaction with the sLeX glycolipid cellular receptor as an essential step before membrane insertion. A similar analysis conducted on streptolysin O from Streptococcus pyogenes revealed that this CDC also has glycan-binding properties and that hemolytic activity against RBCs can be blocked with the glycan lacto-N-neotetraose by inhibiting binding to the cell surface. Together, these data support the emerging paradigm shift that pore-forming toxins, including CDCs, have cellular receptors other than cholesterol that define target cell tropism. PMID:25422425

  1. Lack of the lectin-like domain of thrombomodulin worsens Shiga toxin-associated hemolytic uremic syndrome in mice.

    PubMed

    Zoja, Carlamaria; Locatelli, Monica; Pagani, Chiara; Corna, Daniela; Zanchi, Cristina; Isermann, Berend; Remuzzi, Giuseppe; Conway, Edward M; Noris, Marina

    2012-10-01

    Shiga toxin (Stx)-producing Escherichia coli is a primary cause of diarrhea-associated hemolytic uremic syndrome (HUS), a disorder of thrombocytopenia, microangiopathic hemolytic anemia, and acute renal failure. The pathophysiology of renal microvascular thrombosis in Stx-HUS is still ill-defined. Based on evidence that abnormalities in thrombomodulin (TM), an anticoagulant endothelial glycoprotein that modulates complement and inflammation, predispose to atypical HUS, we assessed whether impaired TM function may adversely affect evolution of Stx-HUS. Disease was induced by coinjection of Stx2/LPS in wild-type mice (TM(wt/wt)) and mice that lack the lectin-like domain of TM (TM(LeD/LeD)), which is critical for its anti-inflammatory and cytoprotective properties. After Stx2/LPS, TM(LeD/LeD) mice exhibited more severe thrombocytopenia and renal dysfunction than TM(wt/wt) mice. Lack of lectin-like domain of TM resulted in a stronger inflammatory reaction after Stx2/LPS with more neutrophils and monocytes/macrophages infiltrating the kidney, associated with PECAM-1 and chemokine upregulation. After Stx2/LPS, intraglomerular fibrin(ogen) deposits were detected earlier in TM(LeD/LeD) than in TM(wt/wt) mice. More abundant fibrin(ogen) deposits were also found in brain and lungs. Under basal conditions, TM(LeD/LeD) mice exhibited excess glomerular C3 deposits, indicating impaired complement regulation in the kidney that could lead to local accumulation of proinflammatory products. TM(LeD/LeD) mice with HUS had a higher mortality rate than TM(wt/wt) mice. If applicable to humans, these findings raise the possibility that genetic or acquired TM defects might have an impact on the severity of microangiopathic lesions after exposure to Stx-producing E. coli infections and raise the potential for using soluble TM in the treatment of Stx-HUS. PMID:22942429

  2. Genetic analysis and functional characterization of novel mutations in a series of patients with atypical hemolytic uremic syndrome.

    PubMed

    Szarvas, Nóra; Szilágyi, Ágnes; Csuka, Dorottya; Takács, Beáta; Rusai, Krisztina; Müller, Thomas; Arbeiter, Klaus; Réti, Marienn; Haris, Ágnes; Wagner, László; Török, Szilárd; Kelen, Kata; Szabó, Attila J; Reusz, György S; Morgan, B Paul; Prohászka, Zoltán

    2016-03-01

    Atypical hemolytic uremic syndrome (aHUS) is a rare disorder caused by dysregulation of the complement alternative pathway, and associated with mutations in genes of complement components and regulators. In the recent years several studies have been published describing these mutations, however, no data is available from the Central and Eastern European region. In this study we present a detailed genetic analysis of our 30 patients, hospitalized with the diagnosis of aHUS in the past 7 years. We analyzed the genetic variants of genes CFH, CFI, CD46, THBD, CFB and C3; furthermore the possible effect of mutations that may alter the function or level of factor H protein was also investigated. We identified 27 (12 novel and 15 previously described) potentially disease-causing mutations in the candidate genes in 23 patients. Genetic analysis of family members revealed that in most cases the disease develops in individuals with multiple genetic risk factors, which may explain the low penetrance of the mutations. Here we showed that two novel mutations (p.W198R, p.P1161T) and a previously reported one (p.R1215Q) in CFH caused impaired regulation as indicated by increased lysis in hemolytic test, while four CFH mutations (p.V609D, p.S722X, p.T1216del and p.C448Y) were associated with decreased factor H protein level in serum as determined by allele-specific immunoassay. These results further point to the necessity of complete genetic workup of patients with aHUS and to the importance of functional characterization of novel variations. PMID:26826462

  3. Membrane-associated CD93 regulates leukocyte migration and C1q-hemolytic activity during murine peritonitis1

    PubMed Central

    Greenlee-Wacker, Mallary C.; Briseño, Carlos; Galvan, Manuel; Moriel, Gabriela; Velázquez, Peter; Bohlson, Suzanne S.

    2011-01-01

    CD93 is emerging as a novel regulator of inflammation; however, its molecular function is unknown. CD93 exists as a membrane-associated glycoprotein on the surface of cells involved in the inflammatory cascade, including endothelial and myeloid cells. A soluble form (sCD93) is detectable in blood and is elevated with inflammation. Here we demonstrate heightened susceptibility to thioglycollate-induced peritonitis in CD93−/− mice. CD93−/− mice showed a 1.6 to 1.8-fold increase in leukocyte infiltration during thioglycollate-induced peritonitis between 3 and 24 hours that returned to wildtype levels by 96 hours. Impaired vascular integrity in CD93−/− mice during peritonitis was demonstrated using fluorescence multi-photon intravital microscopy; however, no differences in cytokine or chemokine levels were detected by Luminex Multiplex or ELISA analysis. C1q-hemolytic activity in CD93−/− mice was decreased by 22% at time zero and by 46% 3 hours post thioglycollate injection suggesting a defect in the classical complement pathway. Leukocyte recruitment and C1q-hemolytic activity was restored to wildtype levels when CD93 was expressed on either hematopoietic cells or non-hematopoietic cells in bone marrow chimeric mice. However, elevated levels of sCD93 in inflammatory fluid were observed only when CD93 was expressed on non-hematopoietic cells. Since cell-associated CD93 was sufficient to restore a normal inflammatory response, these data suggest that cell-associated CD93, and not sCD93, regulates leukocyte recruitment and complement activation during murine peritonitis. PMID:21849679

  4. Membrane-associated CD93 regulates leukocyte migration and C1q-hemolytic activity during murine peritonitis.

    PubMed

    Greenlee-Wacker, Mallary C; Briseño, Carlos; Galvan, Manuel; Moriel, Gabriela; Velázquez, Peter; Bohlson, Suzanne S

    2011-09-15

    CD93 is emerging as a novel regulator of inflammation; however, its molecular function is unknown. CD93 exists as a membrane-associated glycoprotein on the surface of cells involved in the inflammatory cascade, including endothelial and myeloid cells. A soluble form (sCD93) is detectable in blood and is elevated with inflammation. In this study, we demonstrate heightened susceptibility to thioglycollate-induced peritonitis in CD93(-/-) mice. CD93(-/-) mice showed a 1.6-1.8-fold increase in leukocyte infiltration during thioglycollate-induced peritonitis between 3 and 24 h that returned to wild type levels by 96 h. Impaired vascular integrity in CD93(-/-) mice during peritonitis was demonstrated using fluorescence multiphoton intravital microscopy; however, no differences in cytokine or chemokine levels were detected with Luminex Multiplex or ELISA analysis. C1q-hemolytic activity in CD93(-/-) mice was decreased by 22% at time zero and by 46% 3 h after thioglycollate injection, suggesting a defect in the classical complement pathway. Leukocyte recruitment and C1q-hemolytic activity was restored to wild type levels when CD93 was expressed on either hematopoietic cells or nonhematopoietic cells in bone marrow chimeric mice. However, elevated levels of sCD93 in inflammatory fluid were observed only when CD93 was expressed on nonhematopoietic cells. Because cell-associated CD93 was sufficient to restore a normal inflammatory response, these data suggest that cell-associated CD93, and not sCD93, regulates leukocyte recruitment and complement activation during murine peritonitis. PMID:21849679

  5. Complement activation promotes muscle inflammation during modified muscle use

    NASA Technical Reports Server (NTRS)

    Frenette, J.; Cai, B.; Tidball, J. G.

    2000-01-01

    Modified muscle use can result in muscle inflammation that is triggered by unidentified events. In the present investigation, we tested whether the activation of the complement system is a component of muscle inflammation that results from changes in muscle loading. Modified rat hindlimb muscle loading was achieved by removing weight-bearing from the hindlimbs for 10 days followed by reloading through normal ambulation. Experimental animals were injected with the recombinant, soluble complement receptor sCR1 to inhibit complement activation. Assays for complement C4 or factor B in sera showed that sCR1 produced large reductions in the capacity for activation of the complement system through both the classical and alternative pathways. Analysis of complement C4 concentration in serum in untreated animals showed that the classical pathway was activated during the first 2 hours of reloading. Analysis of factor B concentration in untreated animals showed activation of the alternative pathway at 6 hours of reloading. Administration of sCR1 significantly attenuated the invasion of neutrophils (-49%) and ED1(+) macrophages (-52%) that occurred in nontreated animals after 6 hours of reloading. The presence of sCR1 also reduced significantly the degree of edema by 22% as compared to untreated animals. Together, these data show that increased muscle loading activated the complement system which then briefly contributes to the early recruitment of inflammatory cells during modified muscle loading.

  6. A murine model for neuropsychiatric disorders associated with group A beta-hemolytic streptococcal infection.

    PubMed

    Hoffman, Kurt L; Hornig, Mady; Yaddanapudi, Kavitha; Jabado, Omar; Lipkin, W Ian

    2004-02-18

    A syndrome of motoric and neuropsychiatric symptoms comprising various elements, including chorea, hyperactivity, tics, emotional lability, and obsessive-compulsive symptoms, can occur in association with group A beta-hemolytic streptococcal (GABHS) infection. We tested the hypothesis that an immune response to GABHS can result in behavioral abnormalities. Female SJL/J mice were immunized and boosted with a GABHS homogenate in Freund's adjuvant, whereas controls received Freund's adjuvant alone. When sera from GABHS-immunized mice were tested for immunoreactivity to mouse brain, a subset was found to be immunoreactive to several brain regions, including deep cerebellar nuclei (DCN), globus pallidus, and thalamus. GABHS-immunized mice having serum immunoreactivity to DCN also had increased IgG deposits in DCN and exhibited increased rearing behavior in open-field and hole-board tests compared with controls and with GABHS-immunized mice lacking serum anti-DCN antibodies. Rearing and ambulatory behavior were correlated with IgG deposits in the DCN and with serum immunoreactivity to GABHS proteins in Western blot. In addition, serum from a GABHS mouse reacted with normal mouse cerebellum in nondenaturing Western blots and immunoprecipitated C4 complement protein and alpha-2-macroglobulin. These results are consistent with the hypothesis that immune response to GABHS can result in motoric and behavioral disturbances and suggest that anti-GABHS antibodies cross-reactive with brain components may play a role in their pathophysiology. PMID:14973249

  7. Discontinuation of eculizumab maintenance treatment for atypical hemolytic uremic syndrome: a report of 10 cases.

    PubMed

    Ardissino, Gianluigi; Testa, Sara; Possenti, Ilaria; Tel, Francesca; Paglialonga, Fabio; Salardi, Stefania; Tedeschi, Silvana; Belingheri, Mirco; Cugno, Massimo

    2014-10-01

    Atypical hemolytic uremic syndrome (aHUS) is a life-threatening thrombotic microangiopathy, and as many as 70% of patients with aHUS have mutations in the genes encoding complement regulatory proteins. Eculizumab, a humanized recombinant monoclonal antibody targeting C5, has been used successfully in patients with aHUS since 2009. The standard maintenance treatment requires life-long eculizumab therapy, but the possibility of discontinuation has not yet been tested systematically. We report the safety of discontinuing eculizumab treatment in 10 patients who stopped treatment with the aim of minimizing the risk of adverse reactions, reducing the risk of meningitis, and improving quality of life while also reducing the considerable treatment costs. Disease activity was monitored closely at home by means of urine dipstick testing for hemoglobin. During the cumulative observation period of 95 months, 3 of the 10 patients experienced relapse within 6 weeks of discontinuation, but then immediately resumed treatment and completely recovered. Our experience supports the possibility of discontinuing eculizumab therapy with strict home monitoring for early signs of relapse in patients with aHUS who achieve stable remission. PMID:24656451

  8. A New Alkaline pH-Adjusted Medium Enhances Detection of β-Hemolytic Streptococci by Minimizing Bacterial Interference Due to Streptococcus salivarius

    PubMed Central

    Dierksen, Karen P.; Ragland, Nancy L.; Tagg, John R.

    2000-01-01

    A new selective medium (CNA-P) that reduces or eliminates the inhibitory activity of bacteriocin-producing Streptococcus salivarius against β-hemolytic streptococci has been developed and compared with sheep blood agar (SBA) for the sensitive detection of small numbers of β-hemolytic streptococci in clinical specimens. CNA-P has as its basis a commercial medium (Difco Columbia CNA agar) supplemented with 5% (vol/vol) sheep blood, and the CNA is further modified by addition of 100 mM PIPES buffer [piperazine-N,N′-bis(2-ethanesulfonic acid)] (pH 7.5) to maintain cultures at an alkaline pH during incubation. CNA-P was shown to inhibit the production and/or release of four different types of S. salivarius bacteriocins or bacteriocin-like inhibitory molecules. The efficacies of CNA-P and SBA for detection of β-hemolytic streptococci in 1,352 pharyngeal samples from 376 children were compared. The β-hemolytic streptococcal isolates recovered from the samples included 314 group A (S. pyogenes), 61 group G, 33 group B, and 5 group C streptococci. Of 314 samples that yielded S. pyogenes, 300 were positive on CNA-P (96%) and 264 (86%) were positive on SBA. A significantly greater number of S. pyogenes isolates from these samples were recovered only on CNA-P (50 of 314) compared with the number of isolates recovered only on SBA (14 of 314). In addition, the degree of positivity, a measure of the total numbers of S. pyogenes isolates on the plate, was significantly higher on CNA-P than on SBA (2.40 versus 2.07; P < 0.001). Interestingly, CNA-P was also found to enhance the hemolytic activity of streptolysin O, allowing detection of streptolysin S-deficient S. pyogenes strains which might otherwise go undetected on SBA and other isolation media. PMID:10655361

  9. Hemolytic activity in enterotoxigenic and non-enterotoxigenic strains of Escherichia coli.

    PubMed Central

    DeBoy, J M; Wachsmuth, I K; Davis, B R

    1980-01-01

    We screened 223 strains of Escherichia coli belonging to serotypes previously associated with the production of enterotoxin for hemolytic activity, using horse erythrocytes in liquid and in agar media. Thirty-eight were hemolytic. They belonged to nine different serotypes; most (65.8%) belonged to one serotype, O6: H-. Additionally, all 38 strains were specifically assayed for a filterable, heat-labile hemolytic activity previously associated with a hemolysin plasmid. A comparison of hemolytic activity and enterotoxicity showed that none of 32 strains hemolytic in both media was enterotoxigenic; 28 of the 32 expressed heat-labile hemolytic activity. Four of the six strains hemolytic in only one of the media were enterotoxigenic; none of these six expressed heat-labile hemolytic activity. Of 223 strains, 176 that were of human origin and isolated in the United States were further assayed for three traditionally plasmid-mediated characteristics: heat-labile enterotoxin, heat-stable enterotoxin, and colonization factors. The interrelationships of these characteristics, including hemolytic activity, may reflect varying degrees of plasmid compatibility. PMID:7014606

  10. Genetic variations in complement factors in patients with congenital thrombotic thrombocytopenic purpura with renal insufficiency.

    PubMed

    Fan, Xinping; Kremer Hovinga, Johanna A; Shirotani-Ikejima, Hiroko; Eura, Yuka; Hirai, Hidenori; Honda, Shigenori; Kokame, Koichi; Taleghani, Magnus Mansouri; von Krogh, Anne-Sophie; Yoshida, Yoko; Fujimura, Yoshihiro; Lämmle, Bernhard; Miyata, Toshiyuki

    2016-03-01

    The congenital form of thrombotic thrombocytopenic purpura (TTP) is caused by genetic mutations in ADAMTS13. Some, but not all, congenital TTP patients manifest renal insufficiency in addition to microangiopathic hemolysis and thrombocytopenia. We included 32 congenital TTP patients in the present study, which was designed to assess whether congenital TTP patients with renal insufficiency have predisposing mutations in complement regulatory genes, as found in many patients with atypical hemolytic uremic syndrome (aHUS). In 13 patients with severe renal insufficiency, six candidate complement or complement regulatory genes were sequenced and 11 missense mutations were identified. One of these missense mutations, C3:p.K155Q mutation, is a rare mutation located in the macroglobulin-like 2 domain of C3, where other mutations predisposing for aHUS cluster. Several of the common missense mutations identified in our study have been reported to increase disease-risk for aHUS, but were not more common in patients with as compared to those without renal insufficiency. Taken together, our results show that the majority of the congenital TTP patients with renal insufficiency studied do not carry rare genetic mutations in complement or complement regulatory genes. PMID:26830967

  11. Typical Hus: Evidence of Acute Phase Complement Activation from a Daycare Outbreak

    PubMed Central

    Brady, Tammy M; Pruette, Cozumel; Loeffler, Lauren F; Weidemann, Darcy; Strouse, John J; Gavriilaki, Eleni; Brodsky, Robert A

    2016-01-01

    The clinical manifestations of typical hemolytic uremic syndrome (HUS) encompass a wide spectrum. Despite the potentially severe sequelae from this syndrome, treatment approaches remain supportive. We present the clinical course of a child who contracted Shiga toxin-positive E. coli (STEC) from a daycare center during an outbreak. Utilizing the modified Ham test which is a rapid, serum-based functional assay used to detect activation of the alternative pathway of complement as observed in atypical HUS, patient sera revealed evidence of increased complement activation in the acute phase of the syndrome but not after resolution. Further, this complement activation was attenuated by eculizumab in vitro, an effect that was replicated in vitro utilizing Shiga toxin as a stimulus of complement activation in normal serum. Our report suggests that complement blockade may be effective in the treatment of STEC-HUS when initiated early in the disease. Given the epidemic nature of the disease that limits the feasibility of randomized clinical trials, further studies are needed to determine the value of early eculizumab treatment in STEC-HUS. PMID:27413789

  12. Down-regulation of ERK1/2 and AKT-mediated X-ray repair cross-complement group 1 protein (XRCC1) expression by Hsp90 inhibition enhances the gefitinib-induced cytotoxicity in human lung cancer cells

    SciTech Connect

    Tung, Chun-Liang; Jian, Yi-Jun; Syu, Jhan-Jhang; Wang, Tai-Jing; Chang, Po-Yuan; Chen, Chien-Yu; Jian, Yun-Ting; Lin, Yun-Wei

    2015-05-15

    Gefitinib (Iressa{sup R}, ZD1839) is a selective epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) that blocks growth factor-mediated cell proliferation and extracellular signal-regulated kinases 1/2 (ERK1/2) and AKT signaling activation. It has been shown that inhibition of Hsp90 function can enhance antitumor activity of EGFR-TKI. XRCC1 is an important scaffold protein in base excision repair, which could be regulated by ERK1/2 and AKT pathways. However, the role of ERK1/2 and AKT-mediated XRCC1 expression in gefitinib alone or combination with an Hsp90 inhibitor-induced cytotoxicity in non-small cell lung cancer (NSCLC) cells has not been identified. In this study, gefitinib treatment decreased XRCC1 mRNA and protein expression through ERK1/2 and AKT inactivation in two NSCLC cells, A549 and H1975. Knocking down XRCC1 expression by transfection with small interfering RNA of XRCC1 enhanced the cytotoxicity and cell growth inhibition of gefitinib. Combining treatment of gefitinib with an Hsp90 inhibitor resulted in enhancing the reduction of XRCC1 protein and mRNA levels in gefitinib-exposed A549 and H1975 cells. Compared to a single agent alone, gefitinib combined with an Hsp90 inhibitor resulted in cytotoxicity and cell growth inhibition synergistically in NSCLC cells. Furthermore, transfection with constitutive active MKK1 or AKT vectors rescued the XRCC1 protein level as well as the cell survival suppressed by an Hsp90 inhibitor and gefitinib. These findings suggested that down-regulation of XRCC1 can enhance the sensitivity of gefitinib for NSCLC cells. - Highlights: • Gefitinib treatment decreased XRCC1 mRNA and protein expression in NSCLC cells. • Knocking down XRCC1 expression enhanced the cytotoxic effect of gefitinib. • Gefitinib combined with an Hsp90 inhibitor resulted in synergistically cytotoxicity.

  13. Down-regulation of ERK1/2 and AKT-mediated X-ray repair cross-complement group 1 protein (XRCC1) expression by Hsp90 inhibition enhances the gefitinib-induced cytotoxicity in human lung cancer cells.

    PubMed

    Tung, Chun-Liang; Jian, Yi-Jun; Syu, Jhan-Jhang; Wang, Tai-Jing; Chang, Po-Yuan; Chen, Chien-Yu; Jian, Yun-Ting; Lin, Yun-Wei

    2015-05-15

    Gefitinib (Iressa(R), ZD1839) is a selective epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) that blocks growth factor-mediated cell proliferation and extracellular signal-regulated kinases 1/2 (ERK1/2) and AKT signaling activation. It has been shown that inhibition of Hsp90 function can enhance antitumor activity of EGFR-TKI. XRCC1 is an important scaffold protein in base excision repair, which could be regulated by ERK1/2 and AKT pathways. However, the role of ERK1/2 and AKT-mediated XRCC1 expression in gefitinib alone or combination with an Hsp90 inhibitor-induced cytotoxicity in non-small cell lung cancer (NSCLC) cells has not been identified. In this study, gefitinib treatment decreased XRCC1 mRNA and protein expression through ERK1/2 and AKT inactivation in two NSCLC cells, A549 and H1975. Knocking down XRCC1 expression by transfection with small interfering RNA of XRCC1 enhanced the cytotoxicity and cell growth inhibition of gefitinib. Combining treatment of gefitinib with an Hsp90 inhibitor resulted in enhancing the reduction of XRCC1 protein and mRNA levels in gefitinib-exposed A549 and H1975 cells. Compared to a single agent alone, gefitinib combined with an Hsp90 inhibitor resulted in cytotoxicity and cell growth inhibition synergistically in NSCLC cells. Furthermore, transfection with constitutive active MKK1 or AKT vectors rescued the XRCC1 protein level as well as the cell survival suppressed by an Hsp90 inhibitor and gefitinib. These findings suggested that down-regulation of XRCC1 can enhance the sensitivity of gefitinib for NSCLC cells. PMID:25662161

  14. Role of aniline metabolites in aniline-induced hemolytic anemia.

    PubMed

    Harrison, J H; Jollow, D J

    1986-09-01

    Hemolytic anemia after aniline and aniline-related drugs such as dapsone and primaquine is thought to be mediated by active/reactive metabolite(s) formed during the hepatic clearance of the parent compounds. To determine whether any of the known metabolites of aniline contribute to the hemolytic response seen in rats given aniline, rats were infused with isologous 51Cr-labeled erythrocytes 24 hr before administration of aniline or aniline metabolites. The time course of blood radioactivity was followed in individual rats by serial sampling from the orbital sinus and the time required for blood radioactivity to fall by 50% (T50Cr) was used as a measure of in vivo erythrocyte survival. Aniline HCl produced a dose-dependent reduction in the T50Cr. Acetanilide also reduced the T50Cr, but was less potent than aniline. Aminophenols (2-, 3- and 4-) in similar doses did not significantly alter the T50Cr. In contrast, phenylhydroxylamine produced a dose-dependent decrease in the T50Cr with approximately 10 times the potency of aniline. The T50Cr was also decreased in a concentration-dependent manner for labeled erythrocytes incubated in vitro with phenylhydroxylamine, then readministered to rats, indicating a direct toxic effect of phenylhydroxylamine on erythrocytes. In addition, the area under the blood time course curve for phenylhydroxylamine plus nitrosobenzene was equivalent in rats administered equitoxic doses of aniline or phenylhydroxylamine, indicating that sufficient phenylhydroxylamine is formed in vivo during aniline clearance to account for aniline's toxicity. These results suggest that phenylhydroxylamine is the active metabolite that mediates aniline-induced hemolytic anemia. PMID:3746658

  15. Pneumococcal hemolytic uremic syndrome and steroid resistant nephrotic syndrome.

    PubMed

    Groves, Andrew P; Reich, Patrick; Sigdel, Binayak; Davis, T Keefe

    2016-08-01

    Pneumococcal-associated hemolytic uremic syndrome (pHUS) is a rare but severe complication of invasive Streptococcus pneumoniae infection. We report the case of a 12-year-old female with steroid-resistant nephrotic syndrome treated with adrenocorticotrophic hormone (H.P. Acthar(®) Gel), who developed pneumococcal pneumonia and subsequent pHUS. While nephrotic syndrome is a well-known risk factor for invasive pneumococcal disease, this is the first reported case of pHUS in an adolescent patient with nephrotic syndrome, and reveals novel challenges in the diagnosis, treatment and potential prevention of this complication. PMID:27478599

  16. Recurrent Hemolytic and Uremic Syndrome Induced by Escherichia Coli

    PubMed Central

    Commereuc, Morgane; Weill, Francois-Xavier; Loukiadis, Estelle; Gouali, Malika; Gleizal, Audrey; Kormann, Raphaël; Ridel, Christophe; Frémeaux-Bacchi, Véronique; Rondeau, Eric; Hertig, Alexandre

    2016-01-01

    Abstract A widespread belief is that typical hemolytic and uremic syndrome (HUS) does not recur. We report the case of a patient infected twice with raw milk taken from his own cow and containing a Shiga toxin–producing Escherichia coli O174:H21 that induced recurrent HUS causing severe renal and cerebral disorders. A genomic comparison of the human and bovine Shiga toxin–producing Escherichia coli O174:H21 isolates revealed that they were identical. Typical HUS may recur. Since milk from this animal was occasionally distributed locally, thereby posing a serious threat for the whole village, this particular cow was destroyed. PMID:26735524

  17. Recurrent Hemolytic and Uremic Syndrome Induced by Escherichia Coli.

    PubMed

    Commereuc, Morgane; Weill, Francois-Xavier; Loukiadis, Estelle; Gouali, Malika; Gleizal, Audrey; Kormann, Raphaël; Ridel, Christophe; Frémeaux-Bacchi, Véronique; Rondeau, Eric; Hertig, Alexandre

    2016-01-01

    A widespread belief is that typical hemolytic and uremic syndrome (HUS) does not recur. We report the case of a patient infected twice with raw milk taken from his own cow and containing a Shiga toxin-producing Escherichia coli O174:H21 that induced recurrent HUS causing severe renal and cerebral disorders. A genomic comparison of the human and bovine Shiga toxin-producing Escherichia coli O174:H21 isolates revealed that they were identical. Typical HUS may recur. Since milk from this animal was occasionally distributed locally, thereby posing a serious threat for the whole village, this particular cow was destroyed. PMID:26735524

  18. Microangiopathic hemolytic anemia and severe thrombocytopenia in Brucella infection.

    PubMed

    Di Mario, A; Sica, S; Zini, G; Salutari, P; Leone, G

    1995-01-01

    A case of Brucella septicemia presenting at the onset as a severe microangiopathic hemolytic anemia with coexisting dramatic hemorrhagic syndrome (severe epistaxis, gross hematuria, and skin purpura) is reported. A hemogram showed severe thrombocytopenia, anemia, and leukopenia. Bone marrow morphology showed the typical features associated with Brucella infection: numerous histiocytes with signs of activation, multiple granulomata, giant cells, and hemophagocytosis. After appropriate antimicrobial therapy, the clinical and hematological status of the patient improved, and he is alive and well 1 year later with disappearance of all hematological abnormalities. PMID:7827209

  19. Enzymatic and hemolytic properties of Propionibacterium acnes and related bacteria.

    PubMed

    Hoeffler, U

    1977-12-01

    The production of chondroitin sulfatase, hyaluronidase, deoxyribonuclease, gelatinase, phosphatase, lecithinase, and hemolysins was examined in 95 strains of Propionibacterium acnes and four related species of anaerobic, respectively, microaerophilic coryneform bacteria (P. avidum, P. lymphophilum, P. granulosum, and Corynebacterium minutissimum). All enzymes could be demonstrated in at least one representative of the species tested. Those Propionibacterium species most frequently found in acne vulgaris lesions, i.e., P. acnes and P. granulosum, proved to be the most active organisms concerning the production of the enzymes tested. P. avidum, on the other hand, showed the highest rate of hemolytic activity. PMID:201661

  20. Hypothesis: Hemolytic Transfusion Reactions Represent an Alternative Type of Anaphylaxis

    PubMed Central

    Hod, Eldad A.; Sokol, Set A.; Zimring, James C.; Spitalnik, Steven L.

    2009-01-01

    Classical anaphylaxis is the most severe, and potentially fatal, type of allergic reaction, manifested by hypotension, bronchoconstriction, and vascular permeability. Similarly, a hemolytic transfusion reaction (HTR) is the most feared consequence of blood transfusion. Evidence for the existence of an alternative, IgG-mediated pathway of anaphylaxis may be relevant for explaining the pathophysiology of IgG-mediated-HTRs. The purpose of this review is to summarize the evidence for this alternative pathway of anaphylaxis and to present the hypothesis that an IgG-mediated HTR is one example of this type of anaphylaxis. PMID:18830382

  1. Early Identification of Acute Hemolytic Transfusion Reactions: Realistic Implications for Best Practice in Patient Monitoring.

    PubMed

    Menendez, Juliet Battard; Edwards, Barbara

    2016-01-01

    Acute hemolytic transfusion reactions can result in severe complications and death. Through early identification and prompt intervention, nurses can reduce the risks associated with these serious reactions. Realistic evidence-based patient monitoring protocols can help guide identification of acute hemolytic transfusion reactions and facilitate lifesaving interventions to avert critical patient situations. PMID:27323466

  2. Improvisation: A Complement to Curriculum

    ERIC Educational Resources Information Center

    Ronald, Green A.

    2006-01-01

    With the growth of standardized assessment benchmarks in both the public and private paradigms, testing performance matters to institutions more than ever. In an attempt to take as many hindering variables out of this process, such as test anxiety, socioeconomic influences, and latency in cognition, Improvisation: A Complement to Curriculum seeks…

  3. Current approaches for the treatment of autoimmune hemolytic anemia.

    PubMed

    Jaime-Pérez, José Carlos; Rodríguez-Martínez, Marisol; Gómez-de-León, Andrés; Tarín-Arzaga, Luz; Gómez-Almaguer, David

    2013-10-01

    Autoimmune hemolytic anemia (AIHA) is an infrequent group of diseases defined by autoantibody mediated red blood cell destruction. Correct diagnosis and classification of this condition are essential to provide appropriate treatment. AIHA is divided into warm and cold types according to the characteristics of the autoantibody involved and by the presence of an underlying or associated disorder into primary and secondary AIHA. Due to its low frequency, treatment for AIHA is largely based on small prospective trials, case series, and empirical observations. This review describes in detail the different treatment approaches for autoimmune hemolytic anemia. Warm antibody type AIHA should be treated with steroids, to which most patients respond, although relapse can occur and maintenance doses are frequently required. Splenectomy is an effective second line treatment and can provide long-term remission without medication. Rituximab is a useful alternative for steroid refractory patients, those requiring high maintenance doses and unfavorable candidates for surgery. Promising therapeutic modifications with this monoclonal antibody are emerging including drug combinations, lower doses, and long-term use. Primary cold agglutinin disease has been recognized as having a lymphoproliferative monoclonal origin. It is unresponsive to both steroids and splenectomy. Rituximab is currently the best therapeutic alternative for this condition, and several treatment regimens are available with variable responses. PMID:23689532

  4. Hemolytic anemia after kidney transplantation: case report and differential diagnosis.

    PubMed

    Frohn, C; Jabs, W J; Fricke, L; Goerg, S

    2002-03-01

    A 58-year-old woman presented with hemolysis and thrombocytopenia 2 weeks after receiving a kidney graft. Hemolytic uremic syndrome was initially suspected, because in addition to hematological changes the graft function was missing. Unexpectedly, the results of the direct antiglobulin test became positive (4+), which is not normally observed in the hemolytic uremic syndrome. Differentiation of the eluted antibodies revealed anti-rhesus D specificity, which had to be interpreted either as an autoantibody of patient's origin or, hypothetically, as a "graft versus host" antibody of donor origin. Gm- and Km allotyping of these antibodies demonstrated a pattern which differed from the patient's but was identical to that of the kidney donor. Therefore hemolysis could be explained unambiguously by "graft versus host" antibodies. Whether the thrombocytopenia was also due to an immune process was not clear, although some evidence favors this hypothesis. Immunosuppressive treatment remained unchanged and several red blood cell transfusions were necessary before reactivity of the direct antiglobulin test diminished and became negative 7 weeks after kidney transplantation. The occurrence of hemolysis in the early posttransplantation period should thus draw attention to the possibility of "graft versus host" antibodies directed against red cells. Concomitant thrombocytopenia may occur. Donor screening for irregular erythrocyte antibodies should be performed whenever solid organ transplantation is intended. PMID:11904742

  5. Recent approaches for reducing hemolytic activity of chemotherapeutic agents.

    PubMed

    Jeswani, Gunjan; Alexander, Amit; Saraf, Shailendra; Saraf, Swarnlata; Qureshi, Azra; Ajazuddin

    2015-08-10

    Drug induced hemolysis is a frequent complication associated with chemotherapy. It results from interaction of drug with erythrocyte membrane and leads to cell lysis. In recent past, various approaches were made to reduce drug-induced hemolysis, which includes drug polymer conjugation, drug delivery via colloidal carriers and hydrogels, co-administration of botanical agents and modification in molecular chemistry of drug molecules. The basic concept behind these strategies is to protect the red blood cells from membrane damaging effects of drugs. There are several examples of drug polymer conjugate that either are approved by Food and Drug Administration or are under clinical trial for delivering drugs with reduced toxicities. Likewise, colloidal carriers are also used successfully nowadays for the delivery of various chemotherapeutic agents like gemcitabine and amphotericin B with remarkable decrease in their hemolytic activity. Similarly, co-administration of botanical agents with drugs works as secondary system proving protection and strength to erythrocyte membranes. In addition to the above statement, interaction hindrance between RBC and drug molecule by molecular modification plays an important role in reducing hemolysis. This review predominantly describes the above recent approaches explored to achieve the reduced hemolytic activity of drugs especially chemotherapeutic agents. PMID:26047758

  6. Hemolytic mechanism of dioscin proposed by molecular dynamics simulations.

    PubMed

    Lin, Fu; Wang, Renxiao

    2010-01-01

    Saponins are a class of compounds containing a triterpenoid or steroid core with some attached carbohydrate modules. Many saponins cause hemolysis. However, the hemolytic mechanism of saponins at the molecular level is not yet fully understood. In an attempt to explore this issue, we have studied dioscin-a saponin with high hemolytic activity-through extensive molecular dynamics (MD) simulations. Firstly, all-atom MD simulations of 8 ns duration were conducted to study the stability of the dioscin-cholesterol complex and the cholesterol-cholesterol complex in water and in decane, respectively. MM-GB/SA computations indicate that the dioscin-cholesterol complex is energetically more favorable than the cholesterol-cholesterol complex in a non-polar environment. Next, several coarse-grained MD simulations of 400 ns duration were conducted to directly observe the distribution of multiple dioscin molecules on a DPPC-POPC-PSM-CHOL lipid bilayer. Our results indicate that dioscin can penetrate into the lipid bilayer, accumulate in the lipid raft micro-domain, and then bind cholesterol. This leads to the destabilization of lipid raft and consequent membrane curvature, which may eventually result in the hemolysis of red cells. This possible mechanism of hemolysis can well explain some experimental observations on hemolysis. PMID:19513766

  7. SALO, a novel classical pathway complement inhibitor from saliva of the sand fly Lutzomyia longipalpis.

    PubMed

    Ferreira, Viviana P; Fazito Vale, Vladimir; Pangburn, Michael K; Abdeladhim, Maha; Mendes-Sousa, Antonio Ferreira; Coutinho-Abreu, Iliano V; Rasouli, Manoochehr; Brandt, Elizabeth A; Meneses, Claudio; Lima, Kolyvan Ferreira; Nascimento Araújo, Ricardo; Pereira, Marcos Horácio; Kotsyfakis, Michalis; Oliveira, Fabiano; Kamhawi, Shaden; Ribeiro, Jose M C; Gontijo, Nelder F; Collin, Nicolas; Valenzuela, Jesus G

    2016-01-01

    Blood-feeding insects inject potent salivary components including complement inhibitors into their host's skin to acquire a blood meal. Sand fly saliva was shown to inhibit the classical pathway of complement; however, the molecular identity of the inhibitor remains unknown. Here, we identified SALO as the classical pathway complement inhibitor. SALO, an 11 kDa protein, has no homology to proteins of any other organism apart from New World sand flies. rSALO anti-complement activity has the same chromatographic properties as the Lu. longipalpis salivary gland homogenate (SGH)counterparts and anti-rSALO antibodies blocked the classical pathway complement activity of rSALO and SGH. Both rSALO and SGH inhibited C4b deposition and cleavage of C4. rSALO, however, did not inhibit the protease activity of C1s nor the enzymatic activity of factor Xa, uPA, thrombin, kallikrein, trypsin and plasmin. Importantly, rSALO did not inhibit the alternative or the lectin pathway of complement. In conclusion our data shows that SALO is a specific classical pathway complement inhibitor present in the saliva of Lu. longipalpis. Importantly, due to its small size and specificity, SALO may offer a therapeutic alternative for complement classical pathway-mediated pathogenic effects in human diseases. PMID:26758086

  8. SALO, a novel classical pathway complement inhibitor from saliva of the sand fly Lutzomyia longipalpis

    PubMed Central

    Ferreira, Viviana P.; Fazito Vale, Vladimir; Pangburn, Michael K.; Abdeladhim, Maha; Ferreira Mendes-Sousa, Antonio; Coutinho-Abreu, Iliano V.; Rasouli, Manoochehr; Brandt, Elizabeth A.; Meneses, Claudio; Lima, Kolyvan Ferreira; Nascimento Araújo, Ricardo; Horácio Pereira, Marcos; Kotsyfakis, Michalis; Oliveira, Fabiano; Kamhawi, Shaden; Ribeiro, Jose M. C.; Gontijo, Nelder F.; Collin, Nicolas; Valenzuela, Jesus G.

    2016-01-01

    Blood-feeding insects inject potent salivary components including complement inhibitors into their host’s skin to acquire a blood meal. Sand fly saliva was shown to inhibit the classical pathway of complement; however, the molecular identity of the inhibitor remains unknown. Here, we identified SALO as the classical pathway complement inhibitor. SALO, an 11 kDa protein, has no homology to proteins of any other organism apart from New World sand flies. rSALO anti-complement activity has the same chromatographic properties as the Lu. longipalpis salivary gland homogenate (SGH)counterparts and anti-rSALO antibodies blocked the classical pathway complement activity of rSALO and SGH. Both rSALO and SGH inhibited C4b deposition and cleavage of C4. rSALO, however, did not inhibit the protease activity of C1s nor the enzymatic activity of factor Xa, uPA, thrombin, kallikrein, trypsin and plasmin. Importantly, rSALO did not inhibit the alternative or the lectin pathway of complement. In conclusion our data shows that SALO is a specific classical pathway complement inhibitor present in the saliva of Lu. longipalpis. Importantly, due to its small size and specificity, SALO may offer a therapeutic alternative for complement classical pathway-mediated pathogenic effects in human diseases. PMID:26758086

  9. Positive predictive value of diagnosis coding for hemolytic anemias in the Danish National Patient Register

    PubMed Central

    Hansen, Dennis Lund; Overgaard, Ulrik Malthe; Pedersen, Lars; Frederiksen, Henrik

    2016-01-01

    Purpose The nationwide public health registers in Denmark provide a unique opportunity for evaluation of disease-associated morbidity if the positive predictive values (PPVs) of the primary diagnosis are known. The aim of this study was to evaluate the predictive values of hemolytic anemias registered in the Danish National Patient Register. Patients and methods All patients with a first-ever diagnosis of hemolytic anemia from either specialist outpatient clinic contact or inpatient admission at Odense University Hospital from January 1994 through December 2011 were considered for inclusion. Patients with mechanical reason for hemolysis such as an artificial heart valve, and patients with vitamin-B12 or folic acid deficiency were excluded. Results We identified 412 eligible patients: 249 with a congenital hemolytic anemia diagnosis and 163 with acquired hemolytic anemia diagnosis. In all, hemolysis was confirmed in 359 patients, yielding an overall PPV of 87.1% (95% confidence interval [CI]: 83.5%–90.2%). A diagnosis could be established in 392 patients of whom 355 patients had a hemolytic diagnosis. Diagnosis was confirmed in 197 of the 249 patients with congenital hemolytic anemia, yielding a PPV of 79.1% (95% CI: 73.5%–84.0%). Diagnosis of acquired hemolytic anemia could be confirmed in 136 of the 163 patients, resulting in a PPV of 83.4% (95% CI: 76.8%–88.8%). For hemoglobinopathy PPV was 84.1% (95% CI: 77.4%–89.4%), for hereditary spherocytosis PPV was 80.6% (95% CI: 69.5%–88.9%), and for autoimmune hemolytic anemia PPV was 78.4% (95% CI: 70.4%–85.0%). Conclusion The PPV of hemolytic anemias was moderately high. The PPVs were comparable in the three main categories of overall hemolysis, and congenital and acquired hemolytic anemia. PMID:27445504

  10. Magnesium uptake of Arabidopsis transporters, AtMRS2-10 and AtMRS2-11, expressed in Escherichia coli mutants: Complementation and growth inhibition by aluminum.

    PubMed

    Ishijima, Sumio; Uda, Misaki; Hirata, Tomohiro; Shibata, Makiko; Kitagawa, Nozomi; Sagami, Ikuko

    2015-06-01

    Magnesium (Mg2+) plays a critical role in many physiological processes. Mg2+ transport systems in Salmonella have been well documented, but those in Escherichia coli have not been fully elucidated. We examined the effects of corA, mgtA, yhiD and corC gene deletion on Mg2+ transport in E. coli. We obtained every combination of double, triple and quadruple mutants. The corA and mgtA double mutant required addition of 10 mM Mg2+ to Luria-Bertani (LB) medium for growth, and the corA, mgtA and yhiD triple mutant TM2 required a higher Mg2+ concentration. The Mg2+ requirement of the quadruple mutant was similar to that of TM2. The results demonstrated that either CorA or MgtA is necessary for normal E. coli growth in LB medium and that YhiD plays a role in Mg2+ transport under high Mg2+ growth conditions in E. coli. The Arabidopsis Mg2+ transporters, AtMRS2-10 and AtMRS2-11, were heterologously expressed in TM2 cells. TM2 cells expressing AtMRS2-10 and AtMRS2-11 could grow in LB medium that had been supplemented with 1 mM Mg2+ and without Mg2+ supplementation, respectively, and cell growth was inhibited by 2 mM AlCl3. The results indicated that the growth of TM2 expressing AtMRS2-10 and AtMRS2-11 reflected these AtMRS2 function for Mg2+ and aluminum. The E. coli TM2 cells are useful for functional analysis of Arabidopsis MRS2 proteins. PMID:25772503

  11. Bisretinoid-mediated Complement Activation on Retinal Pigment Epithelial Cells Is Dependent on Complement Factor H Haplotype*

    PubMed Central

    Radu, Roxana A.; Hu, Jane; Jiang, Zhichun; Bok, Dean

    2014-01-01

    Age-related macular degeneration (AMD) is a common central blinding disease of the elderly. Homozygosity for a sequence variant causing Y402H and I62V substitutions in the gene for complement factor H (CFH) is strongly associated with risk of AMD. CFH, secreted by many cell types, including those of the retinal pigment epithelium (RPE), is a regulatory protein that inhibits complement activation. Recessive Stargardt maculopathy is another central blinding disease caused by mutations in the gene for ABCA4, a transporter in photoreceptor outer segments (OS) that clears retinaldehyde and prevents formation of toxic bisretinoids. Photoreceptors daily shed their distal OS, which are phagocytosed by the RPE cells. Here, we investigated the relationship between the CFH haplotype of human RPE (hRPE) cells, exposure to OS containing bisretinoids, and complement activation. We show that hRPE cells of the AMD-predisposing CFH haplotype (HH402/VV62) are attacked by complement following exposure to bisretinoid-containing Abca4−/− OS. This activation was dependent on factor B, indicating involvement of the alternative pathway. In contrast, hRPE cells of the AMD-protective CFH haplotype (YY402/II62) showed no complement activation following exposure to either Abca4−/− or wild-type OS. The AMD-protective YY402/II62 hRPE cells were more resistant to the membrane attack complex, whereas HH402/VV62 hRPE cells showed significant membrane attack complex deposition following ingestion of Abca4−/− OS. These results suggest that bisretinoid accumulation in hRPE cells stimulates activation and dysregulation of complement. Cells with an intact complement negative regulatory system are protected from complement attack, whereas cells with reduced CFH synthesis because of the Y402H and I62V substitutions are vulnerable to disease. PMID:24550392

  12. C3 glomerulopathy–associated CFHR1 mutation alters FHR oligomerization and complement regulation

    PubMed Central

    Tortajada, Agustín; Yébenes, Hugo; Abarrategui-Garrido, Cynthia; Anter, Jaouad; García-Fernández, Jesús M.; Martínez-Barricarte, Rubén; Alba-Domínguez, María; Malik, Talat H.; Bedoya, Rafael; Pérez, Rocío Cabrera; Trascasa, Margarita López; Pickering, Matthew C.; Harris, Claire L.; Sánchez-Corral, Pilar; Llorca, Oscar; Rodríguez de Córdoba, Santiago

    2013-01-01

    C3 glomerulopathies (C3G) are a group of severe renal diseases with distinct patterns of glomerular inflammation and C3 deposition caused by complement dysregulation. Here we report the identification of a familial C3G-associated genomic mutation in the gene complement factor H–related 1 (CFHR1), which encodes FHR1. The mutation resulted in the duplication of the N-terminal short consensus repeats (SCRs) that are conserved in FHR2 and FHR5. We determined that native FHR1, FHR2, and FHR5 circulate in plasma as homo- and hetero-oligomeric complexes, the formation of which is likely mediated by the conserved N-terminal domain. In mutant FHR1, duplication of the N-terminal domain resulted in the formation of unusually large multimeric FHR complexes that exhibited increased avidity for the FHR1 ligands C3b, iC3b, and C3dg and enhanced competition with complement factor H (FH) in surface plasmon resonance (SPR) studies and hemolytic assays. These data revealed that FHR1, FHR2, and FHR5 organize a combinatorial repertoire of oligomeric complexes and demonstrated that changes in FHR oligomerization influence the regulation of complement activation. In summary, our identification and characterization of a unique CFHR1 mutation provides insights into the biology of the FHRs and contributes to our understanding of the pathogenic mechanisms underlying C3G. PMID:23728178

  13. MEMBRANE ATTACK BY COMPLEMENT: THE ASSEMBLY AND BIOLOGY OF TERMINAL COMPLEMENT COMPLEXES

    PubMed Central

    Tegla, Cosmin A.; Cudrici, Cornelia; Patel, Snehal; Trippe, Richard; Rus, Violeta; Niculescu, Florin; Rus, Horea

    2013-01-01

    Complement system activation plays an important role in both innate and acquired immunity. Activation of complement and the subsequent formation of C5b-9 channels (the membrane attack complex) on cell membranes lead to cell death. However, when the number of channels assembled on the surface of nucleated cells is limited, sublytic C5b-9 can induce cell cycle progression by activating signal transduction pathways and transcription factors and inhibiting apoptosis. This induction by C5b-9 is dependent upon the activation of the phosphatidylinositol 3-kinase/Akt/FOXO1 and ERK1 pathways in a Gi protein-dependent manner. C5b-9 induces sequential activation of CDK4 and CDK2, enabling the G1/S-phase transition and cellular proliferation. In addition, it induces RGC-32, a novel gene that plays a role in cell cycle activation by interacting with Akt and the cyclin B1-CDC2 complex. C5b-9 also inhibits apoptosis by inducing the phosphorylation of Bad and blocking the activation of FLIP, caspase-8, and Bid cleavage. Thus, sublytic C5b-9 plays an important role in cell activation, proliferation, and differentiation, thereby contributing to the maintenance of cell and tissue homeostasis. PMID:21850539

  14. Intracellular sensing of complement C3 activates cell autonomous immunity

    PubMed Central

    Tam, Jerry C.H.; Bidgood, Susanna R.; McEwan, William A.; James, Leo C.

    2014-01-01

    Pathogens traverse multiple barriers during infection including cell membranes. Here we show that during this transition pathogens carry covalently attached complement C3 into the cell, triggering immediate signalling and effector responses. Sensing of C3 in the cytosol activates MAVS-dependent signalling cascades and induces proinflammatory cytokine secretion. C3 also flags viruses for rapid proteasomal degradation, thereby preventing their replication. This system can detect both viral and bacterial pathogens but is antagonized by enteroviruses, such as rhinovirus and poliovirus, which cleave C3 using their 3C protease. The antiviral Rupintrivir inhibits 3C protease and prevents C3 cleavage, rendering enteroviruses susceptible to intracellular complement sensing. Thus, complement C3 allows cells to detect and disable pathogens that have invaded the cytosol. PMID:25190799

  15. Intracellular sensing of complement C3 activates cell autonomous immunity.

    PubMed

    Tam, Jerry C H; Bidgood, Susanna R; McEwan, William A; James, Leo C

    2014-09-01

    Pathogens traverse multiple barriers during infection, including cell membranes. We found that during this transition, pathogens carried covalently attached complement C3 into the cell, triggering immediate signaling and effector responses. Sensing of C3 in the cytosol activated mitochondrial antiviral signaling (MAVS)-dependent signaling cascades and induced proinflammatory cytokine secretion. C3 also flagged viruses for rapid proteasomal degradation, preventing their replication. This system could detect both viral and bacterial pathogens but was antagonized by enteroviruses, such as rhinovirus and poliovirus, which cleave C3 using their 3C protease. The antiviral rupintrivir inhibited 3C protease and prevented C3 cleavage, rendering enteroviruses susceptible to intracellular complement sensing. Thus, complement C3 allows cells to detect and disable pathogens that have invaded the cytosol. PMID:25190799

  16. Complement Activation in Placental Malaria

    PubMed Central

    McDonald, Chloe R.; Tran, Vanessa; Kain, Kevin C.

    2015-01-01

    Sixty percent of all pregnancies worldwide occur in malaria endemic regions. Pregnant women are at greater risk of malaria infection than their non-pregnant counterparts and have a higher risk of adverse birth outcomes including low birth weight resulting from intrauterine growth restriction and/or preterm birth. The complement system plays an essential role in placental and fetal development as well as the host innate immune response to malaria infection. Excessive or dysregulated complement activation has been associated with the pathobiology of severe malaria and with poor pregnancy outcomes, dependent and independent of infection. Here we review the role of complement in malaria and pregnancy and discuss its part in mediating altered placental angiogenesis, malaria-induced adverse birth outcomes, and disruptions to the in utero environment with possible consequences on fetal neurodevelopment. A detailed understanding of the mechanisms underlying adverse birth outcomes, and the impact of maternal malaria infection on fetal neurodevelopment, may lead to biomarkers to identify at-risk pregnancies and novel therapeutic interventions to prevent these complications. PMID:26733992

  17. Hereditary deficiency of the sixth component of complement in man. I. Immunochemical, biologic, and family studies.

    PubMed Central

    Leddy, J P; Frank, M M; Gaither, T; Baum, J; Klemperer, M R

    1974-01-01

    An 18-yr-old black woman in good general health was found to lack serum hemolytic complement activity. The sixth component of complement (C6) was undetectable by functional assay of serum or plasma and by immunoprecipitin analysis of serum. Functional titers of all other complement components were normal. The absence of C6 in the patient's serum could not be accounted for by a circulating C6 inhibitor, and addition of functionally pure C6 to the patient's serum restored hemolytic activity to normal. Both parents of the proband and five of six available siblings had approximately half the normal levels of functional C6. The other sibling had a normal C6 level. These data suggest that both parents and five siblings are heterozygous for C6 deficiency, while the proband is homozygous and one sibling is normal. Thus, C6 deficiency appears to follow classic mendelian inheritance, with all three possible genotypes recognizable within the family. Functional properties of the proband's C6-deficient serum included total absence of bactericidal activity against Salmonella typhi 0 901 and Hemophilus influenzae, type b, and inability to mediate lysis of red blood cells from patients with paroxysmal nocturnal hemoglobinuria in either the acidified serum or "sugar water" tests. The proband's serum did, however, exhibit a normal capacity (a) to generate chemotactic activity during incubation with bacterial endotoxin or aggregated IgG, (b) to mediate the immune adherence phenomenon, and (c) to coat human red blood cells, sensitized by cold agglutinins, with C4 and C3. Images PMID:11344568

  18. Candida tropicalis from veterinary and human sources shows similar in vitro hemolytic activity, antifungal biofilm susceptibility and pathogenesis against Caenorhabditis elegans.

    PubMed

    Brilhante, Raimunda Sâmia Nogueira; Oliveira, Jonathas Sales de; Evangelista, Antônio José de Jesus; Serpa, Rosana; Silva, Aline Lobão da; Aguiar, Felipe Rodrigues Magalhães de; Pereira, Vandbergue Santos; Castelo-Branco, Débora de Souza Collares Maia; Pereira-Neto, Waldemiro Aquino; Cordeiro, Rossana de Aguiar; Sidrim, José Júlio Costa; Rocha, Marcos Fábio Gadelha

    2016-08-30

    The aim of this study was to evaluate the in vitro hemolytic activity and biofilm antifungal susceptibility of veterinary and human Candida tropicalis strains, as well as their pathogenesis against Caenorhabditis elegans. Twenty veterinary isolates and 20 human clinical isolates of C. tropicalis were used. The strains were evaluated for their hemolytic activity and biofilm production. Biofilm susceptibility to itraconazole, fluconazole, voriconazole, amphotericin B and caspofungin was assessed using broth microdilution assay. The in vivo evaluation of strain pathogenicity was investigated using the nematode C. elegans. Hemolytic factor was observed in 95% of the strains and 97.5% of the isolates showed ability to form biofilm. Caspofungin and amphotericin B showed better results than azole antifungals against mature biofilms. Paradoxical effect on mature biofilm metabolic activity was observed at elevated concentrations of caspofungin (8-64μg/mL). Azole antifungals were not able to inhibit mature C. tropicalis biofilms, even at the higher tested concentrations. High mortality rates of C. elegans were observed when the worms were exposed to with C. tropicalis strains, reaching up to 96%, 96h after exposure of the worms to C. tropicalis strains. These results reinforce the high pathogenicity of C. tropicalis from veterinary and human sources and show the effectiveness of caspofungin and amphotericin B against mature biofilms of this species. PMID:27527785

  19. Quantitative Modeling of the Alternative Pathway of the Complement System.

    PubMed

    Zewde, Nehemiah; Gorham, Ronald D; Dorado, Angel; Morikis, Dimitrios

    2016-01-01

    The complement system is an integral part of innate immunity that detects and eliminates invading pathogens through a cascade of reactions. The destructive effects of the complement activation on host cells are inhibited through versatile regulators that are present in plasma and bound to membranes. Impairment in the capacity of these regulators to function in the proper manner results in autoimmune diseases. To better understand the delicate balance between complement activation and regulation, we have developed a comprehensive quantitative model of the alternative pathway. Our model incorporates a system of ordinary differential equations that describes the dynamics of the four steps of the alternative pathway under physiological conditions: (i) initiation (fluid phase), (ii) amplification (surfaces), (iii) termination (pathogen), and (iv) regulation (host cell and fluid phase). We have examined complement activation and regulation on different surfaces, using the cellular dimensions of a characteristic bacterium (E. coli) and host cell (human erythrocyte). In addition, we have incorporated neutrophil-secreted properdin into the model highlighting the cross talk of neutrophils with the alternative pathway in coordinating innate immunity. Our study yields a series of time-dependent response data for all alternative pathway proteins, fragments, and complexes. We demonstrate the robustness of alternative pathway on the surface of pathogens in which complement components were able to saturate the entire region in about 54 minutes, while occupying less than one percent on host cells at the same time period. Our model reveals that tight regulation of complement starts in fluid phase in which propagation of the alternative pathway was inhibited through the dismantlement of fluid phase convertases. Our model also depicts the intricate role that properdin released from neutrophils plays in initiating and propagating the alternative pathway during bacterial infection. PMID

  20. Quantitative Modeling of the Alternative Pathway of the Complement System

    PubMed Central

    Dorado, Angel; Morikis, Dimitrios

    2016-01-01

    The complement system is an integral part of innate immunity that detects and eliminates invading pathogens through a cascade of reactions. The destructive effects of the complement activation on host cells are inhibited through versatile regulators that are present in plasma and bound to membranes. Impairment in the capacity of these regulators to function in the proper manner results in autoimmune diseases. To better understand the delicate balance between complement activation and regulation, we have developed a comprehensive quantitative model of the alternative pathway. Our model incorporates a system of ordinary differential equations that describes the dynamics of the four steps of the alternative pathway under physiological conditions: (i) initiation (fluid phase), (ii) amplification (surfaces), (iii) termination (pathogen), and (iv) regulation (host cell and fluid phase). We have examined complement activation and regulation on different surfaces, using the cellular dimensions of a characteristic bacterium (E. coli) and host cell (human erythrocyte). In addition, we have incorporated neutrophil-secreted properdin into the model highlighting the cross talk of neutrophils with the alternative pathway in coordinating innate immunity. Our study yields a series of time-dependent response data for all alternative pathway proteins, fragments, and complexes. We demonstrate the robustness of alternative pathway on the surface of pathogens in which complement components were able to saturate the entire region in about 54 minutes, while occupying less than one percent on host cells at the same time period. Our model reveals that tight regulation of complement starts in fluid phase in which propagation of the alternative pathway was inhibited through the dismantlement of fluid phase convertases. Our model also depicts the intricate role that properdin released from neutrophils plays in initiating and propagating the alternative pathway during bacterial infection. PMID

  1. Diagnosis and treatment of cold agglutinin mediated autoimmune hemolytic anemia.

    PubMed

    Berentsen, Sigbjørn; Tjønnfjord, Geir E

    2012-05-01

    Exact diagnosis of the subtype has essential therapeutic consequences in autoimmune hemolytic anemia. Cold-antibody types include primary chronic cold agglutinin disease (CAD) and rare cases of cold agglutinin syndrome (CAS) secondary to cancer or acute infection. Primary CAD is a clonal lymphoproliferative disorder. Not all patients require pharmacological therapy, but treatment seems indicated more often than previously thought. Corticosteroids should not be used to treat primary CAD. Half of the patients respond to rituximab monotherapy; median response duration is 11 months. The most efficient treatment to date is fludarabine and rituximab in combination, resulting in responses in 75%, complete responses in 20% and median response duration of more than 66 months. Toxicity may be a concern, and an individualized approach is discussed. Erythrocyte transfusions can be given provided specific precautions are undertaken. No evidence-based therapy exists in secondary CAS, but optimal treatment of the underlying disorder is essential when feasible. PMID:22330255

  2. Molecular Basis for Group B β -hemolytic Streptococcal Disease

    NASA Astrophysics Data System (ADS)

    Hellerqvist, Carl G.; Sundell, Hakan; Gettins, Peter

    1987-01-01

    Group B β -hemolytic Streptococcus (GBS) is a major pathogen affecting newborns. We have investigated the molecular mechanism underlying the respiratory distress induced in sheep after intravenous injection of a toxin produced by this organism. The pathophysiological response is characterized by pulmonary hypertension, followed by granulocytopenia and increased pulmonary vascular permeability to protein. 31P NMR studies of GBS toxin and model components before and after reductive alkaline hydrolysis demonstrated that phosphodiester residues are an integral part of the GBS toxin. Reductive alkaline treatment cleaves phosphate esters from secondary and primary alcohols and renders GBS toxin nontoxic in the sheep model and inactive as a mediator of elastase release in vitro from isolated human granulocytes. We propose that the interaction of cellular receptors with mannosyl phosphodiester groups plays an essential role in the pathophysiological response to GBS toxin.

  3. [Autoimmune hemolytic anemia with normal serum lactate dehydrogenase level].

    PubMed

    Mizuno, Hideaki; Hangaishi, Akira; Saika, Makoto; Morioka, Takehiko; Ando, Yayoi; Kida, Michiko; Usuki, Kensuke

    2015-11-01

    We herein report two cases of AIHA (autoimmune hemolytic anemia), a 25-year-old woman and a 77-year-old man, who presented with normal serum LDH values. Though in these two cases, low hemoglobin and haptoglobin, high total bilirubin and positive direct Coombs' test results led to the diagnosis of AIHA, both patients had normal LDH levels (218 and 187 IU/l). Both cases were successfully treated with prednisone. In the diagnosis of AIHA, elevated LDH is usually used as a marker of hemolysis. However, medical records of 24 AIHA patients collected in our institute from January 2001 to August 2012 revealed LDH levels to have been normal in 25% of these cases. This report indicates the importance of obtaining complete information about the blood testing of patients and taking these data into account when considering the diagnosis of AIHA. PMID:26666722

  4. [Autoimmune hemolytic anemia in a patient with TAFRO syndrome].

    PubMed

    Edahiro, Yoko; Ichikawa, Kunimoto; Sunami, Yoshitaka; Koike, Michiaki; Komatsu, Norio

    2015-11-01

    TAFRO syndrome is a systemic inflammatory disorder characterized by low platelet counts, anasarca, fever, reticulin fibrosis, renal dysfunction, and organomegaly. Patients with TAFRO syndrome occasionally have courses complicated by immunological diseases. Herein, we describe a case of TAFRO syndrome associated with autoimmune hemolytic anemia (AIHA). The patient was admitted because of menorrhagia. She had thrombocytopenia, pleural effusion and ascites, hepatomegaly, and multiple lymphadenopathies. Her symptoms worsened, especially fever, pleural effusion and ascites, and she developed AIHA. Steroid pulse therapy followed by 45 mg of prednisolone (PSL) improved not only the symptoms of TAFRO syndrome but also those of AIHA. There have been no reports, to our knowledge, of AIHA associated with TAFRO syndrome, and detailed studies on this syndrome are needed. PMID:26666723

  5. Molecular basis for group B beta-hemolytic streptococcal disease.

    PubMed Central

    Hellerqvist, C G; Sundell, H; Gettins, P

    1987-01-01

    Group B beta-hemolytic Streptococcus (GBS) is a major pathogen affecting newborns. We have investigated the molecular mechanism underlying the respiratory distress induced in sheep after intravenous injection of a toxin produced by this organism. The pathophysiological response is characterized by pulmonary hypertension, followed by granulocytopenia and increased pulmonary vascular permeability to protein. 31P NMR studies of GBS toxin and model components before and after reductive alkaline hydrolysis demonstrated that phosphodiester residues are an integral part of the GBS toxin. Reductive alkaline treatment cleaves phosphate esters from secondary and primary alcohols and renders GBS toxin nontoxic in the sheep model and inactive as a mediator of elastase release in vitro from isolated human granulocytes. We propose that the interaction of cellular receptors with mannosyl phosphodiester groups plays an essential role in the pathophysiological response to GBS toxin. PMID:3540959

  6. Autoimmune Hemolytic Anemia in Children: Mayo Clinic Experience.

    PubMed

    Sankaran, Janani; Rodriguez, Vilmarie; Jacob, Eapen K; Kreuter, Justin D; Go, Ronald S

    2016-04-01

    We studied 35 pediatric patients with autoimmune hemolytic anemia seen at Mayo Clinic from 1994 to 2014. The median age was 10.0 years and 65.7% were males. Most had warm antibodies (80.0%) and some secondary to viral (14.3%) or autoimmune disorders (31.4%). Seven (20.0%) patients presented with Evans syndrome, 3 of whom also had common variable immunodeficiency. The median hemoglobin at diagnosis was 6.1 g/dL and 62.8% patients required red cell transfusions. The severity of anemia was worse among children below 10 years (median 5.5 vs. 7.0 g/dL, P=0.01). Steroid was the initial treatment for 88.5% patients, with overall response rate of 82.7% (68.5% complete, 14.2% partial) and median response duration of 10.7 months (range, 0.2 to 129.7+ mo). After median follow-up of 26.6 months, 8 (22.8%) patients relapsed. Salvage treatments included splenectomy, intravenous immunoglobulin, rituximab, and mycophenolate mofetil. Infectious complications occurred in 9 (25.7%) patients and 1 patient died of cytomegalovirus infection. Four patients had cold agglutinin disease and 3 (75.0%) responded to steroids. Autoimmune hemolytic anemia is a rare disorder in pediatric population and most respond well to steroids regardless of the type of antibody. Infectious complications are common and screening for immunodeficiency is recommended among those with Evans syndrome. PMID:26925716

  7. LPS induces pulp progenitor cell recruitment via complement activation.

    PubMed

    Chmilewsky, F; Jeanneau, C; Laurent, P; About, I

    2015-01-01

    Complement system, a major component of the natural immunity, has been recently identified as an important mediator of the dentin-pulp regeneration process through STRO-1 pulp cell recruitment by the C5a active fragment. Moreover, it has been shown recently that under stimulation with lipoteichoic acid, a complex component of the Gram-positive bacteria cell wall, human pulp fibroblasts are able to synthesize all proteins required for complement activation. However, Gram-negative bacteria, which are also involved in tooth decay, are known as powerful activators of complement system and inflammation. Here, we investigated the role of Gram-negative bacteria-induced complement activation on the pulp progenitor cell recruitment using lipopolysaccharide (LPS), a major component of all Gram-negative bacteria. Our results show that incubating pulp fibroblasts with LPS induced membrane attack complex formation and C5a release in serum-free fibroblast cultures. The produced C5a binds to the pulp progenitor cells' membrane and induces their migration toward the LPS stimulation chamber, as revealed by the dynamic transwell migration assays. The inhibition of this migration by the C5aR-specific antagonist W54011 indicates that the pulp progenitor migration is mediated by the interaction between C5a and C5aR. Our findings demonstrate, for the first time, a direct interaction between the recruitment of progenitor pulp cells and the activation of complement system generated by pulp fibroblast stimulation with LPS. PMID:25359783

  8. The complement system and adverse pregnancy outcomes.

    PubMed

    Regal, Jean F; Gilbert, Jeffrey S; Burwick, Richard M

    2015-09-01

    Adverse pregnancy outcomes significantly contribute to morbidity and mortality for mother and child, with lifelong health consequences for both. The innate and adaptive immune system must be regulated to insure survival of the fetal allograft, and the complement system is no exception. An intact complement system optimizes placental development and function and is essential to maintain host defense and fetal survival. Complement regulation is apparent at the placental interface from early pregnancy with some degree of complement activation occurring normally throughout gestation. However, a number of pregnancy complications including early pregnancy loss, fetal growth restriction, hypertensive disorders of pregnancy and preterm birth are associated with excessive or misdirected complement activation, and are more frequent in women with inherited or acquired complement system disorders or complement gene mutations. Clinical studies employing complement biomarkers in plasma and urine implicate dysregulated complement activation in components of each of the adverse pregnancy outcomes. In addition, mechanistic studies in rat and mouse models of adverse pregnancy outcomes address the complement pathways or activation products of importance and allow critical analysis of the pathophysiology. Targeted complement therapeutics are already in use to control adverse pregnancy outcomes in select situations. A clearer understanding of the role of the complement system in both normal pregnancy and complicated or failed pregnancy will allow a rational approach to future therapeutic strategies for manipulating complement with the goal of mitigating adverse pregnancy outcomes, preserving host defense, and improving long term outcomes for both mother and child. PMID:25802092

  9. THE ENDOPARASITOID Campoletis chlorideae INDUCES A HEMOLYTIC FACTOR IN THE HERBIVOROUS INSECT Helicoverpa armigera.

    PubMed

    Wang, Xiong-Ya; Bai, Su-Fen; Li, Xin; Yin, Xin-Ming; Li, Xian-Chun

    2015-09-01

    Although lysis of invading organisms is a major innate form of immunity used by invertebrates, it remains unclear whether herbivorous insects have hemolysin or not. To address this general question, we tested the hemolytic (HL) activity of the hemolymph and tissue extracts from various stages of the polyphagous insect Helicoverpa armigera (Hübner) against the erythrocytes from chicken, duck, and rabbit. An HL activity was identified in the hemolymph of H. armigera larvae. Further studies demonstrated that the HL activity is proteinaceous as it was precipitable by deproteinizing agents. Hemolysins were found in Helicoverpa egg, larva, pupa, and adult, but the activity was higher in feeding larvae than in molting or newly molted larvae. Hemolysins were distributed among a variety of larval tissues including salivary gland, fat body, epidermis, midgut, or testes, but the highest activity was found in salivary gland and fat body. Relative to nonparasitized larvae, parasitization of H. armigera larvae by the endoparasitoid Campoletis chlorideae Uchida induced a 3.4-fold increase in the HL activity in the plasma of parasitized host at day two postparasitization. The present study shows the presence of a parasitoid inducible HL factor in the parasitized insect. The HL activity increased significantly in H. armigera larvae at 12 and 24 h postinjection with Escherichia coli. We infer the HL factor(s) is inducible or due to de novo synthesis, which means that the HL factor(s) is associated with insect immune response by inhibiting or clearance of invading organisms. PMID:25929852

  10. A steryl glycoside fraction with hemolytic activity from tubers of Momordica cochinchinensis.

    PubMed

    Ng, T B; Li, W W; Yeung, H W

    1986-10-01

    A hemolytic fraction has been obtained from fresh tubers of Momordica cochinchinensis. The fraction was strongly adsorbed on DEAE-Sepharose CL6B. It did not stain with Coomassie brilliant blue in SDS-polyacrylamide gel electrophoresis and it gave no immunoprecipitin arcs in immunoelectrophoresis. The hemolytic activity of the fraction was resistant to heat and proteolytic enzymes. The behavior of the fraction in thin-layer chromatography and its positive reaction in Liebermann-Burchard test indicated that the hemolytic activity of the fraction can be attributed to a steryl glycoside(s). PMID:3821135

  11. M. leprae components induce nerve damage by complement activation: identification of lipoarabinomannan as the dominant complement activator.

    PubMed

    Bahia El Idrissi, Nawal; Das, Pranab K; Fluiter, Kees; Rosa, Patricia S; Vreijling, Jeroen; Troost, Dirk; Morgan, B Paul; Baas, Frank; Ramaglia, Valeria

    2015-05-01

    Peripheral nerve damage is the hallmark of leprosy pathology but its etiology is unclear. We previously identified the membrane attack complex (MAC) of the complement system as a key determinant of post-traumatic nerve damage and demonstrated that its inhibition is neuroprotective. Here, we determined the contribution of the MAC to nerve damage caused by Mycobacterium leprae and its components in mouse. Furthermore, we studied the association between MAC and the key M. leprae component lipoarabinomannan (LAM) in nerve biopsies of leprosy patients. Intraneural injections of M. leprae sonicate induced MAC deposition and pathological changes in the mouse nerve, whereas MAC inhibition preserved myelin and axons. Complement activation occurred mainly via the lectin pathway and the principal activator was LAM. In leprosy nerves, the extent of LAM and MAC immunoreactivity was robust and significantly higher in multibacillary compared to paucibacillary donors (p = 0.01 and p = 0.001, respectively), with a highly significant association between LAM and MAC in the diseased samples (r = 0.9601, p = 0.0001). Further, MAC co-localized with LAM on axons, pointing to a role for this M. leprae antigen in complement activation and nerve damage in leprosy. Our findings demonstrate that MAC contributes to nerve damage in a model of M. leprae-induced nerve injury and its inhibition is neuroprotective. In addition, our data identified LAM as the key pathogen associated molecule that activates complement and causes nerve damage. Taken together our data imply an important role of complement in nerve damage in leprosy and may inform the development of novel therapeutics for patients. PMID:25772973

  12. Complement fixation test to C. burnetii

    MedlinePlus

    ... ency/article/003520.htm Complement fixation test to C burnetii To use the sharing features on this ... JavaScript. The complement fixation test to Coxiella burnetii ( C burnetti ) is a blood test that checks for ...

  13. Genetics Home Reference: complement component 8 deficiency

    MedlinePlus

    ... the membranes surrounding the brain and spinal cord (meningitis). Although meningitis can be life-threatening, individuals with complement component ... leaves affected individuals prone to recurrent episodes of meningitis. Learn more about the genes associated with complement ...

  14. A novel peptide inhibitor of classical and lectin complement activation including ABO incompatibility

    PubMed Central

    Mauriello, Clifford T.; Pallera, Haree K.; Sharp, Julia A.; Woltmann, Jon L.; Qian, Shizhi; Hair, Pamela S.; van der Pol, Pieter; van Kooten, Cees; Thielens, Nicole M.; Lattanzio, Frank A.; Cunnion, Kenji M.; Krishna, Neel K.

    2012-01-01

    Previous experiments from our laboratories have identified peptides derived from the human astrovirus coat protein (CP) that bind C1q and mannose binding lectin (MBL) inhibiting activation of the classical and lectin pathways of complement, respectively. The purpose of this study was to evaluate the function of these coat protein peptides (CPPs) in an in vitro model of complement-mediated disease (ABO incompatibility), preliminarily assess their in vivo complement suppression profile and develop more highly potent derivatives of these molecules. E23A, a 30 amino acid CPP derivative previously demonstrated to inhibit classical pathway activation was able to dose-dependently inhibit lysis of AB erythrocytes treated with mismatched human O serum. Additionally, when injected into rats, E23A inhibited the animals’ serum from lysing antibody-sensitized erythrocytes, providing preliminary in vivo functional evidence that this CPP can cross the species barrier to inhibit serum complement activity in rodents. A rational drug design approach was implemented to identify more potent CPP derivatives, resulting in the identification and characterization of a 15 residue peptide (Polar Assortant (PA)), which demonstrated both superior inhibition of classical complement pathway activation and robust binding to C1q collagen-like tails. PA also inhibited ABO incompatibility in vitro and demonstrated in vivo complement suppression up to 24 hours post-injection. CPP’s ability to inhibit ABO incompatibility in vitro, proof of concept in vivo inhibitory activity in rats and the development of the highly potent PA derivative set the stage for preclinical testing of this molecule in small animal models of complement-mediated disease. PMID:22906481

  15. Papillomavirus DNA Complementation in Vivo

    PubMed Central

    Hu, Jiafen; Cladel, Nancy M.; Budgeon, Lynn; Balogh, Karla K.; Christensen, Neil D.

    2009-01-01

    Recent phylogenic studies indicate that DNA recombination could have occurred in ancient papillomaviruses types. However, no experimental data is available to demonstrate this event because of the lack of human papillomavirus infection models. We have used the cottontail rabbit papillomavirus (CRPV)/rabbit model to study pathogenesis and immunogenicity of different mutant genomes in vivo. Although the domestic rabbit is not a natural host for CRPV infection, it is possible to initiate infection with naked CRPV DNA cloned into a plasmid and monitor papilloma outgrowth on these animals. Taking advantage of a large panel of mutants based on a CRPV strain (Hershey CRPV), we tested the hypothesis that two non-viable mutant genomes could induce papillomas by either recombination or complementation. We found that co-infection with a dysfunctional mutant with an E2 transactivation domain mutation and another mutant with an E7 ATG knock out generated papillomas in rabbits. DNA extracted from these papillomas contained genotypes from both parental genomes. Three additional pairs of dysfunctional mutants also showed similar results. Individual wild type genes were also shown to rescue the function of corresponding dysfunctional mutants. Therefore, we suggest that complementation occurred between these two non-viable mutant PV genomes in vivo. PMID:19379784

  16. The first report of cabergoline-induced immune hemolytic anemia in an adolescent with prolactinoma.

    PubMed

    Gürbüz, Fatih; Yağcı-Küpeli, Begül; Kör, Yılmaz; Yüksel, Bilgin; Zorludemir, Suzan; Gürbüz, Berrak Bilginer; Küpeli, Serhan

    2014-01-01

    Prolactinomas are common pituitary tumors that can cause gonadal dysfunction and infertility related to hyperprolactinemia. Dopamine agonists are the first-line treatment in these patients. Cabergoline leads to significant reduction in serum prolactin levels and tumor size in patients with prolactinoma. Dopamine agonists have been associated with adverse effects such as nausea, vomiting and psychosis. We report here a case with cabergoline-induced immune hemolytic anemia. The patient had cabergoline treatment history for prolactinoma and presented with weakness, fatigue, nausea, and paleness. Laboratory findings revealed severe anemia-related immune hemolysis. There were no causes identified to explain hemolytic anemia except cabergoline. Therefore, cabergoline therapy was stopped and subsequently hemolytic anemia resolved and did not occur again. This is the first reported pediatric case with prolactinoma and cabergoline-induced hemolytic anemia. Clinicians should be watchful for this rare side effect induced by cabergoline. PMID:23945126

  17. Auto immune hemolytic anemia in a child precipitated by chicken pox.

    PubMed

    Billoo, Samina Shamim; Jamalvi, Syed Waseem

    2008-05-01

    Auto Immune Hemolytic Anemia (AIHA) is a rare entity in children. We report a case of an adolescent girl with AIHA, which was precipitated by chicken pox. Clinical course over 3 years, till remission is described. PMID:18541094

  18. Human complement protein C9 is a calcium binding protein. Structural and functional implications.

    PubMed

    Thielens, N M; Lohner, K; Esser, A F

    1988-05-15

    Human complement protein C9 is shown to be a metalloprotein that binds 1 mol of Ca2+/mol of C9 with a dissociation constant of 3 micron as measured by equilibrium dialysis. Incubation with EDTA removes the bound calcium, resulting in a apoprotein with decreased thermal stability. This loss in stability leads to aggregation and, therefore, to loss of hemolytic activity upon heating to a few degrees above the physiological temperature. Heat-induced aggregation of apoC9 can be prevented by salts that stabilize proteins according to the Hofmeister series of lyotropic ions, suggesting that the ion in native C9 may ligand with more than one structural element or domain of the protein. Ligand blotting indicates that the calcium binding site is located in the amino-terminal half of the protein. Removal of calcium by inclusion of EDTA in assay mixtures has no effect on the hemolytic activity of C9, and its capacity to bind to C8 in solution, or to small unilamellar lipid vesicles at temperatures at or below the physiological range. Although we do not know yet the precise structural and functional role of the bound calcium, it is clear that it provides thermal stability to C9 and it may have a function in regulation of membrane insertion. PMID:3360798

  19. Complement inhibition as a novel strategy in renal transplantation

    PubMed Central

    Drage, M; Watson, C; Nicholson, M; Sacks, S

    2013-01-01

    Affiliated to the Association of Surgeons in Training and the British Transplantation Society, the Carrel Club is the transplant trainee surgical society. The Carrel Club held a joint meeting with the Chapter of Transplant Surgeons, a subsidiary organisation of the British Transplantation Society, at the Manchester Hilton Hotel on 31 January and 1 February 2013. As part of the meeting, ten abstracts were presented. A selection is printed below. The winner of the Best Presentation award was Mr Mownah.

  20. A case of delayed hemolytic transfusion reaction in sickle cell disease patient

    PubMed Central

    Dogra, Ashu; Sidhu, Meena

    2016-01-01

    Sickle cell disease (SCD) is autosomal recessive, genetically transmitted hemoglobinopathy responsible for considerable morbidity and mortality. It is prevalent in many parts of India including Central India, where the prevalence in different communities has ranged from 9.4% to 22%. Perioperative management may include transfusion of red blood cells. Hemolytic transfusion reactions can occur, and these can be either acute or delayed. We present a case of delayed hemolytic transfusion reaction in a patient with SCD. PMID:27605854

  1. A case of delayed hemolytic transfusion reaction in sickle cell disease patient.

    PubMed

    Dogra, Ashu; Sidhu, Meena

    2016-01-01

    Sickle cell disease (SCD) is autosomal recessive, genetically transmitted hemoglobinopathy responsible for considerable morbidity and mortality. It is prevalent in many parts of India including Central India, where the prevalence in different communities has ranged from 9.4% to 22%. Perioperative management may include transfusion of red blood cells. Hemolytic transfusion reactions can occur, and these can be either acute or delayed. We present a case of delayed hemolytic transfusion reaction in a patient with SCD. PMID:27605854

  2. Effects of Ca2+ on refolding of the recombinant hemolytic lectin CEL-III.

    PubMed

    Hisamatsu, Keigo; Unno, Hideaki; Goda, Shuichiro; Hatakeyama, Tomomitsu

    2009-05-01

    CEL-III is a hemolytic lectin isolated from Cucumaria echinata. Although recombinant CEL-III (rCEL-III) expressed in Escherichia coli showed very weak hemolytic activity compared with native protein, it was considerably enhanced by refolding in the presence of Ca(2+). This suggests that Ca(2+) supported correct folding of the carbohydrate-binding domains of rCEL-III, leading to effective binding to the cell surface and subsequent self-oligomerization. PMID:19420692

  3. Hemolytic Anemia as a Presenting Feature of Wilson’s Disease: A Case Report

    PubMed Central

    Toppo, Anupa; Rath, B.; Harbhajanka, Aparna; Lalita Jyotsna, P.

    2010-01-01

    Wilson’s disease is a rare inherited disorder of copper metabolism causing severe damage to vital organs. Liver and brain disorders are the main manifestations. Severe hemolytic anemia is an unusual complication of Wilson’s disease. We present a case who developed spherocytic acute hemolytic anemia (Coomb’s negative) as the initial manifestation of Wilson’s disease. On examination Kayser- Fleischer ring was found. Laboratory data supported a diagnosis of Wilson’s disease. PMID:21886393

  4. Meningococcal disease and the complement system

    PubMed Central

    Lewis, Lisa A; Ram, Sanjay

    2014-01-01

    Despite considerable advances in the understanding of the pathogenesis of meningococcal disease, this infection remains a major cause of morbidity and mortality globally. The role of the complement system in innate immune defenses against invasive meningococcal disease is well established. Individuals deficient in components of the alternative and terminal complement pathways are highly predisposed to invasive, often recurrent meningococcal infections. Genome-wide analysis studies also point to a central role for complement in disease pathogenesis. Here we review the pathophysiologic events pertinent to the complement system that accompany meningococcal sepsis in humans. Meningococci use several often redundant mechanisms to evade killing by human complement. Capsular polysaccharide and lipooligosaccharide glycan composition play critical roles in complement evasion. Some of the newly described protein vaccine antigens interact with complement components and have sparked considerable research interest. PMID:24104403

  5. Activation of the alternative complement pathway in canine normal serum by Paracoccidioides brasiliensis

    PubMed Central

    Bianchini, A.A.C.; Petroni, T.F.; Fedatto, P.F.; Bianchini, R.R.; Venancio, E.J.; Itano, E.N.; Ono, M.A.

    2009-01-01

    The dimorphic fungus Paracoccidioides brasiliensis is the etiological agent of paracoccidioidomycosis, a human granulomatous disease. Recently the first case of natural disease in dogs was reported. The complement system is an important effector component of humoral immunity against infectious agents. Therefore, the aim of this study was to evaluate the activation of the dog alternative complement pathway by P. brasiliensis. Initially, the ability of erythrocytes of guinea pig, rabbit, sheep, chicken and swine to activate the dog alternative pathway was evaluated. The guinea pig erythrocytes showed the greatest capacity to activate dog alternative pathway. The alternative (AH50) hemolytic activity was evaluated in 27 serum samples from healthy dogs and the mean values were 87.2 AH50/ml. No significant differences were observed in relation to sex and age. The alternative pathway activation by P. brasiliensis was higher in serum samples from adult dogs when compared to puppies and aged dogs (p ≤ 0.05). This is the first report of dog alternative complement pathway activation by P. brasiliensis and suggests that it may play a protective role in canine paracoccidioidomycosis. PMID:24031350

  6. Activation of the alternative complement pathway in canine normal serum by Paracoccidioides brasiliensis.

    PubMed

    Bianchini, A A C; Petroni, T F; Fedatto, P F; Bianchini, R R; Venancio, E J; Itano, E N; Ono, M A

    2009-04-01

    The dimorphic fungus Paracoccidioides brasiliensis is the etiological agent of paracoccidioidomycosis, a human granulomatous disease. Recently the first case of natural disease in dogs was reported. The complement system is an important effector component of humoral immunity against infectious agents. Therefore, the aim of this study was to evaluate the activation of the dog alternative complement pathway by P. brasiliensis. Initially, the ability of erythrocytes of guinea pig, rabbit, sheep, chicken and swine to activate the dog alternative pathway was evaluated. The guinea pig erythrocytes showed the greatest capacity to activate dog alternative pathway. The alternative (AH50) hemolytic activity was evaluated in 27 serum samples from healthy dogs and the mean values were 87.2 AH50/ml. No significant differences were observed in relation to sex and age. The alternative pathway activation by P. brasiliensis was higher in serum samples from adult dogs when compared to puppies and aged dogs (p ≤ 0.05). This is the first report of dog alternative complement pathway activation by P. brasiliensis and suggests that it may play a protective role in canine paracoccidioidomycosis. PMID:24031350

  7. Mortalin/GRP75 Binds to Complement C9 and Plays a Role in Resistance to Complement-dependent Cytotoxicity*

    PubMed Central

    Saar Ray, Moran; Moskovich, Oren; Iosefson, Ohad; Fishelson, Zvi

    2014-01-01

    Mortalin/GRP75, the mitochondrial heat shock protein 70, plays a role in cell protection from complement-dependent cytotoxicity (CDC). As shown here, interference with mortalin synthesis enhances sensitivity of K562 erythroleukemia cells to CDC, whereas overexpression of mortalin leads to their resistance to CDC. Quantification of the binding of the C5b-9 membrane attack complex to cells during complement activation shows an inverse correlation between C5b-9 deposition and the level of mortalin in the cell. Following transfection, mortalin-enhanced GFP (EGFP) is located primarily in mitochondria, whereas mortalinΔ51-EGFP lacking the mitochondrial targeting sequence is distributed throughout the cytoplasm. Overexpressed cytosolic mortalinΔ51-EGFP has a reduced protective capacity against CDC relative to mitochondrial mortalin-EGFP. Mortalin was previously shown by us to bind to components of the C5b-9 complex. Two functional domains of mortalin, the N-terminal ATPase domain and the C-terminal substrate-binding domain, were purified after expression in bacteria. Similar to intact mortalin, the ATPase domain, but not the substrate-binding domain, was found to bind to complement proteins C8 and C9 and to inhibit zinc-induced polymerization of C9. Binding of mortalin to complement C9 and C8 occurs through an ionic interaction that is nucleotide-sensitive. We suggest that to express its full protective effect from CDC, mortalin must first reach the mitochondria. In addition, mortalin can potentially target the C8 and C9 complement components through its ATPase domain and inhibit C5b-9 assembly and stability. PMID:24719326

  8. Differences in uptake of mycobacteria by human monocytes: a role for complement.

    PubMed Central

    Swartz, R P; Naai, D; Vogel, C W; Yeager, H

    1988-01-01

    We investigated the influence of serum factors on the uptake of various species of mycobacteria by human peripheral blood monocytes (PBM). On the basis of the percentage of PBM involved during in vitro uptake, the mycobacteria were of two distinct groups. The mycobacteria of one group, which consisted of Mycobacterium avium complex and M. chelonae, were taken up by many PBM; the other group, consisting of M. tuberculosis, M. kansasii, M. fortuitum, and M. gordonae, were taken up by fewer PBM. M. scrofulaceum was intermediate to these two groups on the basis of its uptake by PBM. Serum depleted of complement by heating or treatment with cobra venom factor significantly reduced the extent of PBM involvement with M. avium complex, indicating that complement is an important serum component mediating the uptake of M. avium complex organisms. Preincubation of mycobacteria with serum containing 10 mM EGTA [ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid] and 10 mM MgCl2 resulted in uptake by a high percentage of PBM, while preincubation in heated serum or serum containing 10 mM EDTA resulted in a significantly reduced percentage of PBM involved in uptake of M. avium complex organisms, indicating that these organisms are activators of the alternative pathway of complement. Incubation of M. avium complex organisms in human serum consumed 51% of the hemolytic complement activity. Parallel experiments indicated that serum had a lesser effect on the uptake of M. tuberculosis. Thus, serum is important in in vitro M. avium complex uptake by PBM; complement has a major role in the effect of serum, but this role is less important with M. tuberculosis. PMID:3137162

  9. Classification and therapeutic approaches in autoimmune hemolytic anemia: an update.

    PubMed

    Michel, Marc

    2011-12-01

    Autoimmune hemolytic anemia (AIHA) is an uncommon autoantibody-mediated immune disorder that affects both children and adults. The diagnosis of AIHA relies mainly on the direct antiglobulin test, which is a highly sensitive and relatively specific test. The classification of AIHA is based on the pattern of the direct antiglobulin test and on the immunochemical properties of the autoantibody (warm or cold type), but also on the presence or absence of an underlying condition or disease (secondary vs primary AIHAs) that may have an impact on treatment and outcome. The distinction between AIHAs due to warm antibody (wAIHA) and AIHAs due to cold antibody is a crucial step of the diagnostic procedure as it influences the therapeutic strategy. Whereas corticosteroids are the cornerstone of treatment in wAIHA, they have no or little efficacy in cold AIHA. In wAIHA that is refractory or dependent to corticosteroids, splenectomy and rituximab are both good alternatives and the benefit?risk ratio of each option must be discussed on an individual basis. In chronic agglutinin disease, the most common variety of cold AIHA in adults, beyond supportive measures, rituximab given either alone or in combination with chemotherapy may be helpful. In this article, the classification of AIHA and the recent progress in therapeutics are discussed. PMID:22077525

  10. Hemolytic E. coli Promotes Colonic Tumorigenesis in Females.

    PubMed

    Jin, Ye; Tang, Senwei; Li, Weilin; Ng, Siew Chien; Chan, Michael W Y; Sung, Joseph J Y; Yu, Jun

    2016-05-15

    Bacterial infection is linked to colorectal carcinogenesis, but the species that contribute to a protumorigenic ecology are ill-defined. Here we report evidence that α-hemolysin-positive (hly(+)) type I Escherichia coli (E. coli) drives adenomagenesis and colorectal cancer in human females but not males. We classified E. coli into four types using a novel typing method to monitor fimH mutation patterns of fecal isolates from adenoma patients (n= 59), colorectal cancer patients (n= 83), and healthy subjects (n= 85). hly(+) type I E. coli was found to be relatively more prevalent in stools from females with adenoma and colorectal cancer, correlating with poor survival in colorectal cancer patients. In mechanistic studies in female mice, we found that hly(+) type 1 E. coli activated expression of the glucose transporter GLUT1 and repressed expression of the tumor suppressor BIM. hly-encoded alpha hemolysin partially accounted for these effects by elevating the levels of HIF1α. Notably, colon tumorigenesis in mice could be promoted by feeding hly(+) type I E. coli to female but not male subjects. Collectively, our findings point to hemolytic type I E. coli as a candidate causative factor of colorectal cancer in human females, with additional potential as a biomarker of disease susceptibility. Cancer Res; 76(10); 2891-900. ©2016 AACR. PMID:27013198

  11. Age-related penetrance of hereditary atypical hemolytic uremic syndrome.

    PubMed

    Sullivan, Maren; Rybicki, Lisa A; Winter, Aurelia; Hoffmann, Michael M; Reiermann, Stefanie; Linke, Hannah; Arbeiter, Klaus; Patzer, Ludwig; Budde, Klemens; Hoppe, Bernd; Zeier, Martin; Lhotta, Karl; Bock, Andreas; Wiech, Thorsten; Gaspert, Ariana; Fehr, Thomas; Woznowski, Magdalena; Berisha, Gani; Malinoc, Angelica; Goek, Oemer-Necmi; Eng, Charis; Neumann, Hartmut P H

    2011-11-01

    Hereditary atypical hemolytic uremic syndrome (aHUS), a dramatic disease frequently leading to dialysis, is associated with germline mutations of the CFH, CD46, or CFI genes. After identification of the mutation in an affected aHUS patient, single-site gene testing of relatives is the preventive care perspective. However, clinical data for family counselling are scarce. From the German-Speaking-Countries-aHUS-Registry, 33 index patients with mutations were approached for permission to offer relatives screening for their family-specific mutations and to obtain demographic and clinical data. Mutation screening was performed using direct sequencing. Age-adjusted penetrance of aHUS was calculated for each gene in index cases and in mutation-positive relatives. Sixty-one relatives comprising 41 parents and 20 other relatives were enrolled and mutations detected in 31/61. In total, 40 research participants had germline mutations in CFH, 19 in CD46 and in 6 CFI. Penetrance at age 40 was markedly reduced in mutation-positive relatives compared to index patients overall with 10% versus 67% (P < 0.001); 6% vs. 67% (P < 0.001) in CFH mutation carriers and 21% vs. 70% (P= 0.003) in CD46 mutation carriers. Age-adjusted penetrance for hereditary aHUS is important to understand the disease, and if replicated in the future, for genetic counselling. PMID:21906045

  12. Neonatal Sulfhemoglobinemia and Hemolytic Anemia Associated With Intestinal Morganella morganii.

    PubMed

    Murphy, Kiera; Ryan, Clodagh; Dempsey, Eugene M; O'Toole, Paul W; Ross, R Paul; Stanton, Catherine; Ryan, C Anthony

    2015-12-01

    Sulfhemoglobinemia is a rare disorder characterized by the presence of sulfhemoglobin in the blood. It is typically drug-induced and may cause hypoxia, end-organ damage, and death through oxygen deprivation. We present here a case of non-drug-induced sulfhemoglobinemia in a 7-day-old preterm infant complicated by hemolytic anemia. Microbiota compositional analysis of fecal samples to investigate the origin of hydrogen sulphide revealed the presence of Morganella morganii at a relative abundance of 38% of the total fecal microbiota at the time of diagnosis. M morganii was not detected in the fecal samples of 40 age-matched control preterm infants. M morganii is an opportunistic pathogen that can cause serious infection, particularly in immunocompromised hosts such as neonates. Strains of M morganii are capable of producing hydrogen sulphide, and virulence factors include the production of a diffusible α-hemolysin. The infant in this case survived intact through empirical oral and intravenous antibiotic therapy, probiotic administration, and red blood cell transfusions. This coincided with a reduction in the relative abundance of M morganii to 3%. Neonatologists should have a high index of suspicion for intestinal pathogens in cases of non-drug-induced sulfhemoglobinemia and consider empirical treatment of the intestinal microbiota in this potentially lethal condition. PMID:26553186

  13. Inherited deficiency of second component of complement and HLA haplotype A10,B18 associated with inflammatory bowel disease.

    PubMed

    Slade, J D; Luskin, A T; Gewurz, H; Kraft, S C; Kirsner, J B; Zeitz, H J

    1978-06-01

    A patient with inflammatory bowel disease and sacroiliitis had haplotypes A10,B18 and Aw32,b18 at the major histocompatibility locus. Serum total complement and C2 hemolytic complement activities were undetectable; levels of the remaining C1-C9 components were normal. The parents, both siblings, and a child each had half-normal levels of C2 and either the A10,B18 or the Aw32,b18 hla haplotype. In a second unrelated family, an only child and both parents developed inflammatory bowel disease. The father and child had HLA haplotype A10,B18, but, along with the mother, each had normal serum levels of hemolytic C and C2. Homozygous C2 deficiency, often in association with the A10,B18 haplotype, has previously been linked with various autoimmune diseases and with propensity to infection. Our findings suggest that C2 deficiency or this haplotype also may predispose to inflammatory diseases of the intestine. PMID:666136

  14. The Role of Complement in Tumor Growth

    PubMed Central

    Pio, Ruben; Corrales, Leticia; Lambris, John D.

    2015-01-01

    Complement is a central part of the immune system that has developed as a first defense against non-self cells. Neoplastic transformation is accompanied by an increased capacity of the malignant cells to activate complement. In fact, clinical data demonstrate complement activation in cancer patients. On the basis of the use of protective mechanisms by malignant cells, complement activation has traditionally been considered part of the body's immunosurveillance against cancer. Inhibitory mechanisms of complement activation allow cancer cells to escape from complement-mediated elimination and hamper the clinical efficacy of monoclonal antibody–based cancer immunotherapies. To overcome this limitation, many strategies have been developed with the goal of improving complement-mediated effector mechanisms. However, significant work in recent years has identified new and surprising roles for complement activation within the tumor microenvironment. Recent reports suggest that complement elements can promote tumor growth in the context of chronic inflammation. This chapter reviews the data describing the role of complement activation in cancer immunity, which offers insights that may aid the development of more effective therapeutic approaches to control cancer. PMID:24272362

  15. Eosinophil granule cationic proteins regulate the classical pathway of complement.

    PubMed Central

    Weiler, J M; Edens, R E; Bell, C S; Gleich, G J

    1995-01-01

    Major basic protein, the primary constituent of eosinophil granules, regulates the alternative and classical pathways of complement. Major basic protein and other eosinophil granule cationic proteins, which are important in mediating tissue damage in allergic disease, regulate the alternative pathway by interfering with C3b interaction with factor B to assemble an alternative pathway C3 convertase. In the present study, eosinophil peroxidase, eosinophil cationic protein and eosinophil-derived neurotoxin, as well as major basic protein, were examined for capacity to regulate the classical pathway. Eosinophil peroxidase, eosinophil cationic protein and major basic protein inhibited formation of cell-bound classical pathway C3 convertase (EAC1,4b,2a), causing 50% inhibition of complement-mediated lysis at about 0.19, 0.75 and 0.5 micrograms/10(7) cellular intermediates, respectively. Eosinophil-derived neurotoxin had no activity on this pathway of complement. The eosinophil granule proteins were examined for activity on the formation of the membrane attack complex. Major basic protein and eosinophil cationic protein had no activity on terminal lysis. In contrast, eosinophil peroxidase inhibited lysis of EAC1,4b,2a,3b,5b, but had only minimal activity on later events in complement lysis. These polycations were then examined to determine the site(s) at which they regulated the early classical pathway. Eosinophil granule polycationic proteins: (1) reduced the Zmax at all time points but had only minimal effect on the Tmax during the formation of the classical pathway C3 convertase (EAC1,4b,2a); (2) inhibited formation of EAC1,4b,2a proportional to C4 but independent of C2 concentration; (3) inhibited fluid phase formation of C1,4b,2a, as reflected by a decrease in C1-induced consumption of C2 over time; and (4) inhibited C1 activity over time without a direct effect on either C4 or C2. These observations suggest that polycations regulate the early classical pathway by

  16. Immunoconglutinin and antibody against fibrinogen products in hemolytic anemia and nephritis resulting from infection with a Haemobartonella-like agent.

    PubMed

    Thoongsuwan, S; Cox, H W

    1981-08-01

    An agent morphologically similar to Haemobartonella muris was isolated from the blood of rats infected with a strain of Trypanosoma lewisi kept at this Department. It caused acute hemolytic anemia, splenomegaly, glomerulonephritis, and death within 5 to 8 days in mature Sprague-Dawley rats. The disease was less severe in weanling rats which usually recovered within 3 to 4 wk. The anemia was accompanied by phagocytosis of erythrocytes by monocytes of the spleen and bone marrow, by high titers of cold-active hemagglutinin, high titers of antibody to the third component of fixed complement (immunoconglutinin), and antibody to fibrinogen/fibrin related products. Filtrates of blood from anemic rats passing a 0.20-micron filter did not produce disease or signs of infections, but filtrate from a 0.45-micron filter was infective. Attempts to grow the agent on rat embryo fibroblast cultures and in embryonated chicken eggs were successful. Tests for bacteria, mycoplasma, and spirochetes gave negative results. Blood of infected rats did not produce signs of infections when inoculated into laboratory mice, and normal rats housed in cages with acutely infected rats did not develop signs of infection or disease. Morphological similarity did not allow differentiation of the agent from H. muris. However, its virulence for mature rats differs markedly from that usually seen in H. muris infection. PMID:7264835

  17. Complement (C3), nutrition, and infection*

    PubMed Central

    Kielmann, A. A.; Curcio, L. M.

    1979-01-01

    Complement (C3) was determined and related to various parameters of nutritional status and past infectious disease experience in a group of 53 rural preschool children in North India. Mean complement level was 25% lower than in an age-matched European reference population. Low complement (C3) levels were associated mainly with children who were both stunted and wasted, as well as with those who had experienced frequent purulent skin infections in the past. PMID:311708

  18. Parasitic scabies mites and associated bacteria joining forces against host complement defence.

    PubMed

    Swe, P M; Reynolds, S L; Fischer, K

    2014-11-01

    Scabies is a ubiquitous and contagious skin disease caused by the parasitic mite Sarcoptes scabiei Epidemiological studies have identified scabies as a causative agent for secondary skin infections caused by Staphylococcus aureus and Streptococcus pyogenes. This is an important notion, as such bacterial infections can lead to serious downstream life-threatening complications. As the complement system is the first line of host defence that confronts invading pathogens, both the mite and bacteria produce a large array of molecules that inhibit the complement cascades. It is hypothesised that scabies mite complement inhibitors may play an important role in providing a favourable micro-environment for the establishment of secondary bacterial infections. This review aims to bring together the current literature on complement inhibition by scabies mites and bacteria associated with scabies and to discuss the proposed molecular link between scabies and bacterial co-infections. PMID:25081184

  19. Clinical hypothermia temperatures increase complement activation and cell destruction via the classical pathway

    PubMed Central

    2014-01-01

    Background Therapeutic hypothermia is a treatment modality that is increasingly used to improve clinical neurological outcomes for ischemia-reperfusion injury-mediated diseases. Antibody-initiated classical complement pathway activation has been shown to contribute to ischemia-reperfusion injury in multiple disease processes. However, how therapeutic hypothermia affects complement activation is unknown. Our goal was to measure the independent effect of temperature on complement activation, and more specifically, examine the relationship between clinical hypothermia temperatures (31–33°C), and complement activation. Methods Antibody-sensitized erythrocytes were used to assay complement activation at temperatures ranging from 0-41°C. Individual complement pathway components were assayed by ELISA, Western blot, and quantitative dot blot. Peptide Inhibitor of complement C1 (PIC1) was used to specifically inhibit activation of C1. Results Antibody-initiated complement activation resulting in eukaryotic cell lysis was increased by 2-fold at 31°C compared with 37°C. Antibody-initiated complement activation in human serum increased as temperature decreased from 37°C until dramatically decreasing at 13°C. Quantitation of individual complement components showed significantly increased activation of C4, C3, and C5 at clinical hypothermia temperatures. In contrast, C1s activation by heat-aggregated IgG decreased at therapeutic hypothermia temperatures consistent with decreased enzymatic activity at lower temperatures. However, C1q binding to antibody-coated erythrocytes increased at lower temperatures, suggesting that increased classical complement pathway activation is mediated by increased C1 binding at therapeutic hypothermia temperatures. PIC1 inhibited hypothermia-enhanced complement-mediated cell lysis at 31°C by up to 60% (P = 0.001) in a dose dependent manner. Conclusions In summary, therapeutic hypothermia temperatures increased antibody

  20. Role of complement in multiorgan failure.

    PubMed

    Rittirsch, Daniel; Redl, Heinz; Huber-Lang, Markus

    2012-01-01

    Multiorgan failure (MOF) represents the leading cause of death in patients with sepsis and systemic inflammatory response syndrome (SIRS) following severe trauma. The underlying immune response is highly complex and involves activation of the complement system as a crucial entity of innate immunity. Uncontrolled activation of the complement system during sepsis and SIRS with in excessive generation of complement activation products contributes to an ensuing dysfunction of various organ systems. In the present review, mechanisms of the inflammatory response in the development of MOF in sepsis and SIRS with particular focus on the complement system are discussed. PMID:23320021

  1. Complement and dysbiosis in periodontal disease

    PubMed Central

    Hajishengallis, George; Lambris, John D.

    2012-01-01

    Signaling crosstalk between complement and Toll-like receptors (TLRs) normally serves to coordinate host immunity. However, the periodontal bacterium Porphyromonas gingivalis expresses C5 convertase-like enzymatic activity and adeptly exploits complement-TLR crosstalk to subvert host defenses and escape elimination. Intriguingly, this defective immune surveillance leads to the remodeling of the periodontal microbiota to a dysbiotic state that causes inflammatory periodontitis. Understanding the mechanisms by which P. gingivalis modulates complement function to cause dysbiosis offers new targets for complement therapeutics. PMID:22964237

  2. Cystalysin, a 46-kilodalton cysteine desulfhydrase from Treponema denticola, with hemolytic and hemoxidative activities.

    PubMed Central

    Chu, L; Ebersole, J L; Kurzban, G P; Holt, S C

    1997-01-01

    A 46-kDa hemolytic protein, referred to as cystalysin, from Treponema denticola ATCC 35404 was overexpressed in Escherichia coli LC-67. Both the native and recombinant 46-kDa proteins were purified to homogeneity. Both proteins expressed identical biological and functional characteristics. In addition to its biological function of lysing erythrocytes and hemoxidizing the hemoglobin to methemoglobin, cystalysin was also capable of removing the sulfhydryl and amino groups from selected S-containing compounds (e.g., cysteine) producing H2S, NH3, and pyruvate. This cysteine desulfhydrase resulted in the following Michaelis-Menten kinetics: Km = 3.6 mM and k(cat) = 12 s(-1). Cystathionine and S-aminoethyl-L-cysteine were also substrates for the protein. Gas chromatography-mass spectrometry and high-performance liquid chromatography analysis of the end products revealed NH3, pyruvate, homocysteine (from cystathionine), and cysteamine (from S-aminoethyl-L-cysteine). The enzyme was active over a broad pH range, with highest activity at pH 7.8 to 8.0. The enzymatic activity was increased by beta-mercaptoethanol. It was not inhibited by the proteinase inhibitor TLCK (N alpha-p-tosyl-L-lysine chloromethyl ketone), pronase, or proteinase K, suggesting that the functional site was physically protected or located in a small fragment of the polypeptide. We hypothesize that cystalysin is a pyridoxal-5-phosphate-containing enzyme, with activity of an alphaC-N and betaC-S lyase (cystathionase) type. Since large amounts of H2S have been reported in deep periodontal pockets, cystalysin may also function in vivo as an important virulence molecule. PMID:9234780

  3. Radiation resistance of a hemolytic micrococcus isolated from chicken meat

    SciTech Connect

    Tan, S.T.

    1982-01-01

    The effects of environmental factors on a highly radiation-resistant hemolytic micrococcus isolated from chicken meat were studied. NaCl tolerance and gamma radiation resistance of the cells were growth phase-related. The cells were resistant to injury from drying or freezing/thawing. Under certain conditions, cells in the frozen state required approximately 5 Mrad to inactivate 90% of the population; 0.2 Mrad injured an equivalent proportion. Survival curve of the cells heated at 60/sup 0/C showed a unique pattern which was in three distinct phases. Heat-stressed cells were much more sensitive to radiation inactivation than unheated cells. When suspended in fresh m-Plate Count Broth (PCB), the injured cells repaired without multiplication during incubation at 32/sup 0/C. The repair process in this bacterium, however, was slower compared to thermally injured organisms studied by other workers. An improved replica-plating technique, was devised for isolation of radiation-sensitive mutants of pigmented bacteria. A simple method to demonstrate radiation-inducible radiation resistance in microbial cells was developed. The new method required neither washing/centrifugation nor procedures for cell enumeration. Mutagenesis treatment of radiation-resistant micrococcal bacterium with N-methyl-N'-nitro-N-nitrosoguanidine (NTG) followed by FPR and screening steps resulted in isolation of two radiation-sensitive mutants. The more sensitive mutant strain, designated as 702, was seven times as sensitive to gamma or UC radiation as the wild type. No apparent difference was observed between 702 and the wild type in (1) cell morphology, colonial morphology, and pigment production or (2) tolerance to NaCl, drying/storage, freezing/thawing, and heating. Sodium dodecyl sulfate treatment (for curing) of wild type did not result in isolation of a radiation-sensitive mutant.

  4. Recurrent Isolated Neonatal Hemolytic Anemia: Think About Glutathione Synthetase Deficiency.

    PubMed

    Signolet, Isabelle; Chenouard, Rachel; Oca, Florine; Barth, Magalie; Reynier, Pascal; Denis, Marie-Christine; Simard, Gilles

    2016-09-01

    Hemolytic anemia (HA) of the newborn should be considered in cases of rapidly developing, severe, or persistent hyperbilirubinemia. Several causes of corpuscular hemolysis have been described, among which red blood cell enzyme defects are of particular concern. We report a rare case of red blood cell enzyme defect in a male infant, who presented during his first months of life with recurrent and isolated neonatal hemolysis. All main causes were ruled out. At 6.5 months of age, the patient presented with gastroenteritis requiring hospitalization; fortuitously, urine organic acid chromatography revealed a large peak of 5-oxoproline. Before the association between HA and 5-oxoprolinuria was noted, glutathione synthetase deficiency was suspected and confirmed by a low glutathione synthetase concentration and a collapse of glutathione synthetase activity in erythrocytes. Moreover, molecular diagnosis revealed 2 mutations in the glutathione synthetase gene: a previously reported missense mutation (c.[656A>G]; p.[Asp219Gly]) and a mutation not yet described in the binding site of the enzyme (c.[902T>C]; p.[Leu301Pro]). However, 15 days later, a control sample revealed no signs of 5-oxoprolinuria and the clinical history discovered administration of acetaminophen in the 48 hours before hospitalization. Thus, in this patient, acetaminophen exposure allowed the diagnosis of a mild form of glutathione synthetase deficiency, characterized by isolated HA. Early diagnosis is important because treatment with bicarbonate, vitamins C and E, and elimination of trigger factors are recommended to improve long-term outcomes. Glutathione synthetase deficiency should be screened for in cases of unexplained newborn HA. PMID:27581854

  5. Expansion of CD8+ cells in autoimmune hemolytic anemia.

    PubMed

    Smirnova, S Ju; Sidorova, Ju V; Tsvetaeva, N V; Nikulina, O F; Biderman, B V; Nikulina, E E; Kulikov, S M; Sudarikov, A B

    2016-05-01

    Autoimmune hemolytic anemia (AIHA) is a rare blood disease associated with the production of auto-antibodies and autoimmune hemolysis. A critical role of B-cells in the development of AIHA has been demonstrated before. Here, we present the analysis of the clonal T-cell populations in patients with AIHA. Thirty-three patients with AIHA were included in this study. Thirteen patients with other anemias, 14 patients with other autoimmune conditions (SLE - 6, RA - 8) and 20 healthy donors were included in the study as a control group. The clonality of T-cell was evaluated by the assessment of the T-cell receptor gamma and beta chain gene rearrangements (TCRG and TCRB). The incidence of T-cell monoclonality detected in patients with AIHA was significantly higher compared to the control group. The persistence of T-cell clones did not correlate with the level of hemoglobin and other signs of remission or relapse and did not disappear after the therapy and clinical improvement (observation period was between 1 and 10 years). There was no correlation between the T-cell clonality and the gender, age, splenectomy, duration or severity of the disease. Fractionation of T-lymphocytes (CD4+, CD8+, CD4+25+) revealed that the monoclonal T-cells belonged to the CD8+ sub-population. We assume that besides a possible causative role of the T-cell clones in AIHA to autoimmune process, these clones do not directly participate in the development and maintenance of hemolysis. Most of the AIHA patients (48.5%) demonstrated a T-cell monoclonality, which requires monitoring and should be distinguished from T-cell tumors. PMID:26829107

  6. Salivary agglutinin is the major component in human saliva that modulates the lectin pathway of the complement system.

    PubMed

    Gunput, Sabrina Tg; Wouters, Diana; Nazmi, Kamran; Cukkemane, Nivedita; Brouwer, Mieke; Veerman, Enno Ci; Ligtenberg, Antoon Jm

    2016-05-01

    Saliva interacts with blood after mucosal damage or leakage of gingival crevicular fluid. Surface-adsorbed salivary agglutinin (SAG) activates the lectin pathway (LP) of the complement system via mannose-binding lectin, while SAG in solution inhibits complement activation. In the present study we investigated if, next to SAG, whole and glandular saliva itself and other salivary glycoproteins activate or inhibit the LP. Complement activation was measured by detecting C4 deposition on microtiter plates coated with saliva or purified proteins. Complement inhibition was measured after incubating serum with saliva or proteins in microtiter plates coated with mannan, an LP activator. Adsorbed whole, sublingual and submandibular saliva showed LP-dependent complement activation. Blood group secretors, but not non-secretors, activated the LP. Saliva of both secretors and non-secretors inhibited C4 deposition on mannan. After depletion of SAG, saliva no longer inhibited the LP. Other salivary proteins, including amylase, MUC5B and histatin 2, did not activate or inhibit the LP. Surface-adsorbed whole saliva and glandular saliva samples activate the LP of complement, depending on the presence of SAG and the secretor status of the donor. In solution, saliva inhibits the LP, depending on the presence of SAG, but independent of the secretor status. PMID:27048414

  7. Infectious diseases associated with complement deficiencies.

    PubMed Central

    Figueroa, J E; Densen, P

    1991-01-01

    The complement system consists of both plasma and membrane proteins. The former influence the inflammatory response, immune modulation, and host defense. The latter are complement receptors, which mediate the cellular effects of complement activation, and regulatory proteins, which protect host cells from complement-mediated injury. Complement activation occurs via either the classical or the alternative pathway, which converge at the level of C3 and share a sequence of terminal components. Four aspects of the complement cascade are critical to its function and regulation: (i) activation of the classical pathway, (ii) activation of the alternative pathway, (iii) C3 convertase formation and C3 deposition, and (iv) membrane attack complex assembly and insertion. In general, mechanisms evolved by pathogenic microbes to resist the effects of complement are targeted to these four steps. Because individual complement proteins subserve unique functional activities and are activated in a sequential manner, complement deficiency states are associated with predictable defects in complement-dependent functions. These deficiency states can be grouped by which of the above four mechanisms they disrupt. They are distinguished by unique epidemiologic, clinical, and microbiologic features and are most prevalent in patients with certain rheumatologic and infectious diseases. Ethnic background and the incidence of infection are important cofactors determining this prevalence. Although complement undoubtedly plays a role in host defense against many microbial pathogens, it appears most important in protection against encapsulated bacteria, especially Neisseria meningitidis but also Streptococcus pneumoniae, Haemophilus influenzae, and, to a lesser extent, Neisseria gonorrhoeae. The availability of effective polysaccharide vaccines and antibiotics provides an immunologic and chemotherapeutic rationale for preventing and treating infection in patients with these deficiencies. PMID

  8. Anti-complement activity of the Ixodes scapularis salivary protein Salp20.

    PubMed

    Hourcade, Dennis E; Akk, Antonina M; Mitchell, Lynne M; Zhou, Hui-fang; Hauhart, Richard; Pham, Christine T N

    2016-01-01

    Complement, a major component of innate immunity, presents a rapid and robust defense of the intravascular space. While regulatory proteins protect host cells from complement attack, when these measures fail, unrestrained complement activation may trigger self-tissue injury, leading to pathologic conditions. Of the three complement activation pathways, the alternative pathway (AP) in particular has been implicated in numerous disease and injury states. Consequently, the AP components represent attractive targets for therapeutic intervention. The common hard-bodied ticks from the family Ixodidae derive nourishment from the blood of their mammalian hosts. During its blood meal the tick is exposed to host immune effectors, including the complement system. In defense, the tick produces salivary proteins that can inhibit host immune functions. The Salp20 salivary protein of Ixodes scapularis inhibits the host AP pathway by binding properdin and dissociating C3bBbP, the active C3 convertase. In these studies we examined Salp20 activity in various complement-mediated pathologies. Our results indicate that Salp20 can inhibit AP-dependent pathogenesis in the mouse. Its efficacy may be part in due to synergic effects it provides with the endogenous AP regulator, factor H. While Salp20 itself would be expected to be highly immunogenic and therefore inappropriate for therapeutic use, its emergence speaks for the potential development of a non-immunogenic Salp20 mimic that replicates its anti-properdin activity. PMID:26675068

  9. Characterization of a New DGKE Intronic Mutation in Genetically Unsolved Cases of Familial Atypical Hemolytic Uremic Syndrome

    PubMed Central

    Mele, Caterina; Lemaire, Mathieu; Iatropoulos, Paraskevas; Piras, Rossella; Bresin, Elena; Bettoni, Serena; Bick, David; Helbling, Daniel; Veith, Regan; Valoti, Elisabetta; Donadelli, Roberta; Murer, Luisa; Neunhäuserer, Maria; Breno, Matteo; Frémeaux-Bacchi, Véronique; Lifton, Richard; Noris, Marina

    2015-01-01

    Background and objectives Genetic and acquired abnormalities causing dysregulation of the complement alternative pathway contribute to atypical hemolytic uremic syndrome (aHUS), a rare disorder characterized by thrombocytopenia, nonimmune microangiopathic hemolytic anemia, and acute kidney failure. However, in a substantial proportion of patients the disease-associated alterations are still unknown. Design, setting, participants, & measurements Whole-exome and whole-genome sequencing were performed in two unrelated families with infantile recessive aHUS. Sequencing of cDNA from affected individuals was used to test for the presence of aberrant mRNA species. Expression of mutant diacylglycerol kinase epsilon (DGKE) protein was evaluated with western blotting. Results Whole-exome sequencing analysis with conventional variant filtering parameters did not reveal any obvious candidate mutation in the first family. The report of aHUS-associated mutations in DGKE, encoding DGKE, led to re-examination of the noncoding DGKE variants obtained from next-generation sequencing, allowing identification of a novel intronic DGKE mutation (c.888+40A>G) that segregated with disease. Sequencing of cDNA from affected individuals revealed aberrant forms of DGKE mRNA predicted to cause profound abnormalities in the protein catalytic site. By whole-genome sequencing, the same mutation was found in compound heterozygosity with a second nonsense DGKE mutation in all affected siblings of another unrelated family. Homozygous and compound heterozygous patients presented similar clinical features, including aHUS presentation in the first year of life, multiple relapsing episodes, and proteinuria, which are prototypical of DGKE-associated aHUS. Conclusions This is the first report of a mutation located beyond the exon-intron boundaries in aHUS. Intronic mutations such as these are underreported because conventional filtering parameters used to process next-generation sequencing data routinely

  10. Complement resistance mechanisms of Klebsiella pneumoniae.

    PubMed

    Doorduijn, Dennis J; Rooijakkers, Suzan H M; van Schaik, Willem; Bardoel, Bart W

    2016-10-01

    The current emergence of antibiotic-resistant bacteria causes major problems in hospitals worldwide. To survive within the host, bacterial pathogens exploit several escape mechanisms to prevent detection and killing by the immune system. As a major player in immune defense, the complement system recognizes and destroys bacteria via different effector mechanisms. The complement system can label bacteria for phagocytosis or directly kill Gram-negative bacteria via insertion of a pore-forming complex in the bacterial membrane. The multi-drug resistant pathogen Klebsiella pneumoniae exploits several mechanisms to resist complement. In this review, we present an overview of strategies used by K. pneumoniae to prevent recognition and killing by the complement system. Understanding these complement evasion strategies is crucial for the development of innovative strategies to combat K. pneumoniae. PMID:27364766

  11. Detection and characterisation of Complement protein activity in bovine milk by bactericidal sequestration assay.

    PubMed

    Maye, Susan; Stanton, Catherine; Fitzgerald, Gerald F; Kelly, Philip M

    2015-08-01

    While the Complement protein system in human milk is well characterised, there is little information on its presence and activity in bovine milk. Complement forms part of the innate immune system, hence the importance of its contribution during milk ingestion to the overall defences of the neonate. A bactericidal sequestration assay, featuring a Complement sensitive strain, Escherichia coli 0111, originally used to characterise Complement activity in human milk was successfully applied to freshly drawn bovine milk samples, thus, providing an opportunity to compare Complement activities in both human and bovine milks. Although not identical in response, the levels of Complement activity in bovine milk were found to be closely comparable with that of human milk. Differential counts of Esch. coli 0111 after 2 h incubation were 6.20 and 6.06 log CFU/ml, for raw bovine and human milks, respectively - the lower value representing a stronger Complement response. Exposing bovine milk to a range of thermal treatments e.g. 42, 45, 65, 72, 85 or 95 °C for 10 min, progressively inhibited Complement activity by increasing temperature, thus confirming the heat labile nature of this immune protein system. Low level Complement activity was found, however, in 65 and 72 °C heat treated samples and in retailed pasteurised milk which highlights the outer limit to which high temperature, short time (HTST) industrial thermal processes should be applied if retention of activity is a priority. Concentration of Complement in the fat phase was evident following cream separation, and this was also reflected in the further loss of activity recorded in low fat variants of retailed pasteurised milk. Laboratory-based churning of the cream during simulated buttermaking generated an aqueous (buttermilk) phase with higher levels of Complement activity than the fat phase, thus pointing to a likely association with the milk fat globule membrane (MFGM) layer. PMID:26119290

  12. Early Cytokine Release in Response to Live Borrelia burgdorferi Sensu Lato Spirochetes Is Largely Complement Independent

    PubMed Central

    Säve, Susanne; Bergström, Sven; Forsberg, Pia; Jonsson, Nina; Ernerudh, Jan; Ekdahl, Kristina N.

    2014-01-01

    Aim Here we investigated the role of complement activation in phagocytosis and the release of cytokines and chemokines in response to two clinical isolates: Borrelia afzelii K78, which is resistant to complement-mediated lysis, and Borrelia garinii LU59, which is complement-sensitive. Methods Borrelia spirochetes were incubated in hirudin plasma, or hirudin-anticoagulated whole blood. Complement activation was measured as the generation of C3a and sC5b-9. Binding of the complement components C3, factor H, C4, and C4BP to the bacterial surfaces was analyzed. The importance of complement activation on phagocytosis, and on the release of cytokines and chemokines, was investigated using inhibitors acting at different levels of the complement cascade. Results 1) Borrelia garinii LU59 induced significantly higher complement activation than did Borrelia afzelii K78. 2) Borrelia afzelii K78 recruited higher amounts of factor H resulting in significantly lower C3 binding. 3) Both Borrelia strains were efficiently phagocytized by granulocytes and monocytes, with substantial inhibition by complement blockade at the levels of C3 and C5. 4) The release of the pro-inflammatory cytokines and chemokines IL-1β, IL-6, TNF, CCL20, and CXCL8, together with the anti-inflammatory IL-10, were increased the most (by>10-fold after exposure to Borrelia). 5) Both strains induced a similar release of cytokines and chemokines, which in contrast to the phagocytosis, was almost totally unaffected by complement blockade. Conclusions Our results show that complement activation plays an important role in the process of phagocytosis but not in the subsequent cytokine release in response to live Borrelia spirochetes. PMID:25265036

  13. Current Understanding of the Role of Complement in IgA Nephropathy.

    PubMed

    Maillard, Nicolas; Wyatt, Robert J; Julian, Bruce A; Kiryluk, Krzysztof; Gharavi, Ali; Fremeaux-Bacchi, Veronique; Novak, Jan

    2015-07-01

    Complement activation has a role in the pathogenesis of IgA nephropathy, an autoimmune disease mediated by pathogenic immune complexes consisting of galactose-deficient IgA1 bound by antiglycan antibodies. Of three complement-activation pathways, the alternative and lectin pathways are involved in IgA nephropathy. IgA1 can activate both pathways in vitro, and pathway components are present in the mesangial immunodeposits, including properdin and factor H in the alternative pathway and mannan-binding lectin, mannan-binding lectin-associated serine proteases 1 and 2, and C4d in the lectin pathway. Genome-wide association studies identified deletion of complement factor H-related genes 1 and 3 as protective against the disease. Because the corresponding gene products compete with factor H in the regulation of the alternative pathway, it has been hypothesized that the absence of these genes could lead to more potent inhibition of complement by factor H. Complement activation can take place directly on IgA1-containing immune complexes in circulation and/or after their deposition in the mesangium. Notably, complement factors and their fragments may serve as biomarkers of IgA nephropathy in serum, urine, or renal tissue. A better understanding of the role of complement in IgA nephropathy may provide potential targets and rationale for development of complement-targeting therapy of the disease. PMID:25694468

  14. Refractory atypical hemolytic uremic syndrome with monoclonal gammopathy responsive to bortezomib-based therapy.

    PubMed

    Cheungpasitporn, Wisit; Leung, Nelson; Sethi, Sanjeev; Gertz, Morie A; Fervenza, Fernando C

    2015-06-01

    Atypical hemolytic uremic syndrome (aHUS) is a relatively rare disorder described by the triad of hemolytic anemia, thrombocytopenia, and renal failure. Atypical HUS could be genetic, acquired, or idiopathic (without known genetic changes or environmental triggers). Monoclonal protein has uncommonly been reported as a cause of microangiopathic hemolytic anemia (MAHA). We report a 59-year-old white man who presented with acute kidney injury (AKI) with MAHA and was given a diagnosis of aHUS with monoclonal gammopathy. His kidney function and proteinuria worsened with persistent hemolysis despite eculizumab and later cyclophosphamide and prednisone treatment. He responded well to VRD (bortezomib, lenalidomide, and dexamethasone) regimen. Renal function, proteinuria, and hemolysis all improved, and he was been in remission for more than 15 months. To our knowledge, this is the first report of successful treatment with bortezomib-based regimen for a patient with aHUS and monoclonal protein refractory to eculizumab therapy. PMID:25345382

  15. Carbamazepine-induced hemolytic and aplastic crises associated with reduced glutathione peroxidase activity of erythrocytes.

    PubMed

    Yamamoto, Masaki; Suzuki, Nobuhiro; Hatakeyama, Naoki; Kubo, Noriaki; Tachi, Nobutada; Kanno, Hitoshi; Fujii, Hisaichi; Tsutsumi, Hiroyuki

    2007-11-01

    Although pure red cell aplasia is a well-known side effect of carbamazepine treatment, intravascular hemolytic anemia is rare. We describe a 5-year-old boy who developed concurrent intravascular hemolytic anemia and erythroblastopenia, probably due to carbamazepine. Carbamazepine treatment was subsequently discontinued, and the patient was treated with red blood cell transfusions, haptoglobin, and methylprednisolone. His hematologic abnormalities were almost fully recovered within 2 weeks. Examination of the patient's and mother's erythrocyte enzyme activities revealed mildly decreased erythrocyte glutathione peroxidase (GSH-Px) activity. We speculate that patients with reduced GSH-Px activity are at a high risk of developing carbamazepine-induced hemolytic crisis and/or aplastic crisis. PMID:18055338

  16. Hemolytic activity of plasma and urine from rabbits experimentally infected with Legionella pneumophila.

    PubMed

    Baine, W B; Rasheed, J K; Maca, H W; Kaufmann, A F

    1979-01-01

    Rabbits were infected with Legionella pneumophila by intravenous administration of allantoic fluid from eggs infected with this organism. Heated plasma from animals with severe illness caused by L. pneumophila lysed erythrocytes from guinea pigs in a radial hemolysis assay. Plasma from control rabbits did not lyse guinea pig erythrocytes in parallel assays. Urine from two of the infected animals also showed hemolytic activity. Attempts to induce illness in rabbits by intranasal administration of L. pneumohpila were less successful. Allantoic fluid from embrynated hen eggs developed hemolytic activity when maintained eithr in vitro at room temperature or in eggs whose embryos were killed by refrigeration. Hemolytic activity in filtrates of allantoic fluid from eggs infected with L. pneumophila, as previously reported, may not be due to the presence of bacterial hemolysins in the fluid. PMID:399383

  17. [Enterohemorrhagic Escherichia coli and hemolytic-uremic syndrome].

    PubMed

    Allerberger, F; Sölder, B; Caprioli, A; Karch, H

    1997-09-19

    Enterohemorrhagic Escherichia coli (EHEC) are increasingly identified as the cause of diarrhea and hemorrhagic colitis in countries with highly developed livestock. In 5-10% of patients, full-blown hemolytic uremic syndrome (HUS) occurs as a postinfectious life-threatening complication. Up to 1996, 5 out of 39 patients (12.8%) with EHEC O157 infections in Austria developed HUS. Acute complications of HUS such as brain edema may also lead to death; one fatal outcome has been observed so far in Austrian patients. Aside from the cytotoxic Shiga toxins, other different pathogenic factors are often found in clinical EHEC isolates. These include a cytolysin termed EHEC-hemolysin and a low molecular heat-stabile enterotoxin. Furthermore, most EHEC strains express an important surface protein, intimin, which is important for adherence to intestinal epithelial cells. EHEC are heterogeneous in their antigenic structure (O-, H-antigens). In Austria O157:H7 and O157:H- are the dominating serogroups; in 1997 the first Austrian case of HUS due to EHEC O26:H11 was documented. Because there are no known reliable phenotypical markers for EHEC, diagnostic strategies should focus on the demonstration of Shiga toxins or Shiga toxin genes. For epidemiological purposes it is also important to attempt to isolate the causative agent. Cows and other ruminants are reservoirs for EHEC. In the Tyrol 3% of unpasteurised milk samples, up to 10% of minced beef samples, and 6% of calves yield EHEC O157. Aside from transmission via contaminated food, direct transmission from person to person also plays a major role in the chain of EHEC infection. In contrast to Italy and Bavaria, Austria has not experienced a major outbreak due to this organism so far. A nationwide surveillance system of HUS has shown an incidence of 0.37 HUS cases per 100,000 residents in the age group 0-14 years for 1995 (Italy: 0.2 cases per 100,000; Bavaria: approx. 1.5 cases per 100,000). PMID:9381722

  18. Comparison of Hemagglutination and Hemolytic Activity of Various Bacterial Clinical Isolates Against Different Human Blood Groups

    PubMed Central

    HRV, Rajkumar; Devaki, Ramakrishna

    2016-01-01

    Among the various pathogenic determinants shown by microorganisms hemagglutination and hemolysin production assume greater significance in terms of laboratory identification. This study evaluated the hemagglutination and hemolytic activity of various bacterial isolates against different blood groups. One hundred and fifty bacterial strains, isolated from clinical specimens like urine, pus, blood, and other body fluids were tested for their hemagglutinating and hemolytic activity against human A, B, AB, and O group red blood cells. Among the 150 isolates 81 were Escherichia coli, 18 were Klebsiella pneumoniae, 19 were Pseudomonas aeruginosa, 10 were Pseudomonas spp, six were Proteus mirabilis, and the rest 16 were Staphylococcus aureus. Nearly 85% of the isolates agglutinated A group cells followed by B and AB group (59.3% and 60.6% respectively). Least number of isolates agglutinated O group cells (38.0%). When the hemolytic activity was tested, out of these 150 isolates 79 (52.6%) hemolyzed A group cells, 61 (40.6%) hemolyzed AB group cells, 46 (30.6%) hemolyzed B group cells, and 57 (38.6%) isolates hemolyzed O group cells. Forty-six percent of the isolates exhibited both hemagglutinating and hemolytic property against A group cells, followed by B and AB group cells (28.6% and 21.3% respectively). Least number of isolates i.e., 32 (21.3%) showed both the properties against O group cells. The isolates showed wide variation in their hemagglutination and hemolytic properties against different combinations of human blood group cells. The study highlights the importance of selection of the type of cells especially when human RBCs are used for studying the hemagglutination and hemolytic activity of bacterial isolates because these two properties are considered as characteristic of pathogenic strains. PMID:27014523

  19. Comparison of Hemagglutination and Hemolytic Activity of Various Bacterial Clinical Isolates Against Different Human Blood Groups.

    PubMed

    Hrv, Rajkumar; Devaki, Ramakrishna; Kandi, Venkataramana

    2016-01-01

    Among the various pathogenic determinants shown by microorganisms hemagglutination and hemolysin production assume greater significance in terms of laboratory identification. This study evaluated the hemagglutination and hemolytic activity of various bacterial isolates against different blood groups. One hundred and fifty bacterial strains, isolated from clinical specimens like urine, pus, blood, and other body fluids were tested for their hemagglutinating and hemolytic activity against human A, B, AB, and O group red blood cells. Among the 150 isolates 81 were Escherichia coli, 18 were Klebsiella pneumoniae, 19 were Pseudomonas aeruginosa, 10 were Pseudomonas spp, six were Proteus mirabilis, and the rest 16 were Staphylococcus aureus. Nearly 85% of the isolates agglutinated A group cells followed by B and AB group (59.3% and 60.6% respectively). Least number of isolates agglutinated O group cells (38.0%). When the hemolytic activity was tested, out of these 150 isolates 79 (52.6%) hemolyzed A group cells, 61 (40.6%) hemolyzed AB group cells, 46 (30.6%) hemolyzed B group cells, and 57 (38.6%) isolates hemolyzed O group cells. Forty-six percent of the isolates exhibited both hemagglutinating and hemolytic property against A group cells, followed by B and AB group cells (28.6% and 21.3% respectively). Least number of isolates i.e., 32 (21.3%) showed both the properties against O group cells. The isolates showed wide variation in their hemagglutination and hemolytic properties against different combinations of human blood group cells. The study highlights the importance of selection of the type of cells especially when human RBCs are used for studying the hemagglutination and hemolytic activity of bacterial isolates because these two properties are considered as characteristic of pathogenic strains. PMID:27014523

  20. Alpha-Methyldopa-Induced Autoimmune Hemolytic Anemia in the Third Trimester of Pregnancy

    PubMed Central

    Tympa, Aliki; Liapis, Angelos; Hassiakos, Dimitrios; Bakas, Panagiotis

    2013-01-01

    Alpha-methyldopa has been demonstrated to be safe for use during pregnancy and is now used to treat gestational hypertension. In pregnancy, alpha-methyldopa-induced autoimmune hemolytic anemia does not have typical features and the severity of symptoms ranges from mild fatigue to dyspnea, respiratory failure, and death if left untreated. A case of alpha-methyldopa-induced autoimmune hemolytic anemia in a 36-year-old gravida 2, para 1 woman at 37+6 weeks of gestation is reported herein along with the differential diagnostic procedure and the potential risks to the mother and the fetus. PMID:24175105

  1. Case of cytomegalovirus-associated direct anti-globulin test-negative autoimmune hemolytic anemia.

    PubMed

    Kaneko, Saeko; Sato, Masanori; Sasaki, Goro; Eguchi, Hiroyuki; Oishi, Tsutomu; Kamesaki, Toyomi; Kawaguchi, Hiroyuki

    2013-12-01

    A 1-year-old boy developed autoimmune hemolytic anemia after a negative direct anti-globulin test. The concentration of erythrocyte membrane-associated immunoglobulin G, determined using an immunoradiometric assay, correlated with disease activity. He was positive for cytomegalovirus (CMV) both serologically and by quantitative real-time polymerase chain reaction, indicating that his autoimmune hemolytic anemia was directly caused by CMV infection. Since anti-CMV immunoglobulin G was not absorbed by the patient's erythrocytes, cross-reaction between erythrocyte antigens and CMV was not likely a causative factor for hemolysis. PMID:24330288

  2. Hemolytic disease of the newborn caused by maternal anti-Dib: a case report in Taiwan.

    PubMed

    Chen, C C; Broadberry, R E; Chang, F C; Ding, F; Lin, M

    1993-10-01

    Possibly the first case of hemolytic disease caused by anti-Dib in a Chinese infant is reported. The infant developed jaundice soon after birth; based on study, the jaundice has been diagnosed as a result of maternal anti-Dib which was most likely induced by previous pregnancies. The phenotype of the mother's red cells was Di (a+b-). The frequency of the Dia antigen among Chinese in Taiwan is 3.2%. In Orientals, hemolytic disease of the newborn caused by maternal anti-Dib is likely to be more severe than that caused by anti-Dia. PMID:8258120

  3. Antibiotic hypersensitivity in CF: drug-induced life-threatening hemolytic anemia in a pediatric patient.

    PubMed

    Chavez, Alma; Mian, Amir; Scurlock, Amy M; Blackall, Douglas; Com, Gulnur

    2010-12-01

    Adverse reactions to antibiotics in patients with cystic fibrosis (CF) are a growing concern. We report the case of a pediatric patient with CF with multiple comorbidities and a history of drug reactions, who developed life-threatening piperacillin-induced immune hemolytic anemia. We review drug-induced hemolytic anemia (DIIHA) in particular, and antibiotic hypersensitivity in CF in general, including the frequency, pathogenesis, and risk factors. Finally, we discuss the treatment options and propose an algorithm for the management of drug-induced hypersensitivity reactions in patients with CF. PMID:20833594

  4. Alternative complement pathway and factor B activities in rats with altered blood levels of thyroid hormone

    PubMed Central

    Bitencourt, C.S.; Duarte, C.G.; Azzolini, A.E.C.S.; Assis-Pandochi, A.I.

    2012-01-01

    Evaluating the activity of the complement system under conditions of altered thyroid hormone levels might help elucidate the role of complement in triggering autoimmune processes. Here, we investigated alternative pathway (AP) activity in male Wistar rats (180 ± 10 g) after altering their thyroid hormone levels by treatment with triiodothyronine (T3), propylthiouracil (PTU) or thyroidectomy. T3 and thyroxine (T4) levels were determined by chemiluminescence assays. Hemolytic assays were performed to evaluate the lytic activity of the AP. Factor B activity was evaluated using factor B-deficient serum. An anti-human factor B antibody was used to measure factor B levels in serum by radial immunodiffusion. T3 measurements in thyroidectomized animals or animals treated with PTU demonstrated a significant reduction in hormone levels compared to control. The results showed a reduction in AP lytic activity in rats treated with increasing amounts of T3 (1, 10, or 50 µg). Factor B activity was also decreased in the sera of hyperthyroid rats treated with 1 to 50 µg T3. Additionally, treating rats with 25 µg T3 significantly increased factor B levels in their sera (P < 0.01). In contrast, increased factor B concentration and activity (32%) were observed in hypothyroid rats. We conclude that alterations in thyroid hormone levels affect the activity of the AP and factor B, which may in turn affect the roles of AP and factor B in antibody production. PMID:22370704

  5. Structural Analysis and Anti-Complement Activity of Polysaccharides from Kjellmaniella crsaaifolia

    PubMed Central

    Zhang, Wenjing; Jin, Weihua; Sun, Delin; Zhao, Luyu; Wang, Jing; Duan, Delin; Zhang, Quanbin

    2015-01-01

    Two polysaccharides, named KCA and KCW, were extracted from Kjellmaniella crassifolia using dilute hydrochloric acid and water, respectively. Composition analysis showed that these polysaccharides predominantly consisted of fucose, with galactose, mannose and glucuronic acid as minor components. After degradation and partial desulfation, electrospray ionization mass spectrometry (ESI-MS) was performed, which showed that the polysaccharides consisted of sulfated fucooligosaccharides, sulfated galactofucooligosaccharides and methyl glycosides of mono-sulfated/multi-sulfated fucooligosaccharides. The structures of the oligomeric fragments were further characterized by electrospray ionization collision-induced dissociation tandem mass spectrometry (ESI-CID-MS2 and ESI-CID-MS3). Moreover, the activity of KCA and KCW against the hemolytic activity of both the classical and alternative complement pathways was determined. The activity of KCA was found to be similar to KCW, suggesting that the method of extraction did not influence the activity. In addition, the degraded polysaccharides (DKCA and DKCW) displayed lower activity levels than the crude polysaccharides (KCA and KCW), indicating that molecular weight had an effect on activity. Moreover, the desulfated fractions (ds-DKCA and ds-DKCW) showed less or no activity, which confirmed that sulfate was important for activity. In conclusion, polysaccharides from K. crassifolia may be good candidates for the treatment of diseases involving the complement pathway. PMID:25786064

  6. Infections Revealing Complement Deficiency in Adults

    PubMed Central

    Audemard-Verger, A.; Descloux, E.; Ponard, D.; Deroux, A.; Fantin, B.; Fieschi, C.; John, M.; Bouldouyre, A.; Karkowsi, L.; Moulis, G.; Auvinet, H.; Valla, F.; Lechiche, C.; Davido, B.; Martinot, M.; Biron, C.; Lucht, F.; Asseray, N.; Froissart, A.; Buzelé, R.; Perlat, A.; Boutboul, D.; Fremeaux-Bacchi, V.; Isnard, S.; Bienvenu, B.

    2016-01-01

    Abstract Complement system is a part of innate immunity, its main function is to protect human from bacterial infection. As genetic disorders, complement deficiencies are often diagnosed in pediatric population. However, complement deficiencies can also be revealed in adults but have been poorly investigated. Herein, we describe a case series of infections revealing complement deficiency in adults to study clinical spectrum and management of complement deficiencies. A nationwide retrospective study was conducted in French university and general hospitals in departments of internal medicine, infectious diseases enrolling patients older than 15 years old who had presented at least one infection leading to a complement deficiency diagnosis. Forty-one patients included between 2002 and 2015 in 19 different departments were enrolled in this study. The male-to-female ratio was 1.3 and the mean age at diagnosis was 28 ± 14 (15–67) years. The main clinical feature was Neisseria meningitidis meningitis 75% (n = 31/41) often involving rare serotype: Y (n = 9) and W 135 (n = 7). The main complement deficiency observed was the common final pathway deficiency 83% (n = 34/41). Half of the cohort displayed severe sepsis or septic shock at diagnosis (n = 22/41) but no patient died. No patient had family history of complement deficiency. The mean follow-up was 1.15 ± 1.95 (0.1–10) years. Half of the patients had already suffered from at least one infection before diagnosis of complement deficiency: meningitis (n = 13), pneumonia (n = 4), fulminans purpura (n = 1), or recurrent otitis (n = 1). Near one-third (n = 10/39) had received prophylactic antibiotics (cotrimoxazole or penicillin) after diagnosis of complement deficiency. The vaccination coverage rate, at the end of the follow-up, for N meningitidis, Streptococcus pneumonia, and Haemophilius influenzae were, respectively, 90% (n = 33/37), 47% (n = 17/36), and 35

  7. Exploiting the Nephrotoxic Effects of Venom from the Sea Anemone, Phyllodiscus semoni, to Create a Hemolytic Uremic Syndrome Model in the Rat

    PubMed Central

    Mizuno, Masashi; Ito, Yasuhiko; Morgan, B. Paul

    2012-01-01

    In the natural world, there are many creatures with venoms that have interesting and varied activities. Although the sea anemone, a member of the phylum Coelenterata, has venom that it uses to capture and immobilise small fishes and shrimp and for protection from predators, most sea anemones are harmless to man. However, a few species are highly toxic; some have venoms containing neurotoxins, recently suggested as potential immune-modulators for therapeutic application in immune diseases. Phyllodiscus semoni is a highly toxic sea anemone; the venom has multiple effects, including lethality, hemolysis and renal injuries. We previously reported that venom extracted from Phyllodiscus semoni induced acute glomerular endothelial injuries in rats resembling hemolytic uremic syndrome (HUS), accompanied with complement dysregulation in glomeruli and suggested that the model might be useful for analyses of pathology and development of therapeutic approaches in HUS. In this mini-review, we describe in detail the venom-induced acute renal injuries in rat and summarize how the venom of Phyllodiscus semoni could have potential as a tool for analyses of complement activation and therapeutic interventions in HUS. PMID:22851928

  8. Leishmania species: mechanisms of complement activation by five strains of promastigotes.

    PubMed

    Mosser, D M; Burke, S K; Coutavas, E E; Wedgwood, J F; Edelson, P J

    1986-12-01

    The interaction of fresh serum with promastigotes of Leishmania major, L. donovani, L. mexicana mexicana, L. mexicana amazonensis, and L. braziliensis guyanensis results in lysis of all strains tested with either fresh human or guinea pig serum at 37 C for 30 min. Lysis does not occur in the cold and requires divalent cations and complement that is active hemolytically. Serum deficient in the eighth component of complement is not lytic. Lysis of L. major, L. mexicana, and L. braziliensis proceeds fully in human serum containing EGTA/Mg2+ or in guinea pig serum deficient in the fourth complement component. These species consume only small amounts of C4 from human serum and do not require calcium to optimally bind C3. The data indicate that all are activators of the alternative complement pathway and that the classical pathway is not required for the lysis of these organisms. Promastigotes of L. donovani, in contrast, activate the classical pathway. The presence of calcium is required for both optimal C3 binding and parasite lysis, and L. donovani promastigotes consume C4 when incubated in human serum. In high concentrations, human serum agglutinates all tested Leishmania spp. The agglutinating factor does not require divalent cations, is heat stable, and works at 4 C, suggesting that it is an antibody. This "naturally occurring" antibody cross reacts with all Leishmania spp. and agglutinates them. The adsorption of serum with any Leishmania species or with beads that are Protein A coated, removes the agglutinogen. This factor causes a slight enhancement in alternative pathway activation by L. major and mediates the classical activation by L. donovani. In adsorbed serum, L. donovani promastigotes only weakly activate the alternative complement pathway. Increased concentrations of adsorbed serum are therefore necessary for lysis to proceed. The titer can be partially restored by the addition of heat inactivated serum. Using purified components of the classical cascade

  9. Genetics Home Reference: complement factor I deficiency

    MedlinePlus

    ... Page Baracho GV, Nudelman V, Isaac L. Molecular characterization of homozygous hereditary factor I deficiency. Clin Exp ... G, Sánchez-Corral P, López-Trascasa M. Molecular characterization of Complement Factor I deficiency in two Spanish ...

  10. Nomenclature for human complement component C2*

    PubMed Central

    1992-01-01

    This note describes the designations for variants of the human complement component C2, which were approved by the Nomenclature Committee of the International Union of Immunological Societies (IUIS). PMID:1394787

  11. Virus-induced gene complementation in tomato

    PubMed Central

    Kong, Jinhua; Chen, Weiwei; Shen, Jiajia; Qin, Cheng; Lai, Tongfei; Zhang, Pengcheng; Wang, Ying; Wu, Chaoqun; Yang, Xin; Hong, Yiguo

    2013-01-01

    Virus-induced gene complementation (VIGC), a plant virus technology based on Potato virus X for transient overexpression of endogenous genes complemented tomato mutants, resulting in non-ripening fruits to ripen. This efficient “gain-of-function” approach involves no stable transformation, and reveals a fruit-specific transcriptional network that may exist among key transcription factors in modulating tomato ripening. Thus, VIGC represents a novel and feasible strategy for gene functional analysis in plants. PMID:24305652

  12. Complement regulatory proteins are incorporated into lentiviral vectors and protect particles against complement inactivation.

    PubMed

    Schauber-Plewa, C; Simmons, A; Tuerk, M J; Pacheco, C D; Veres, G

    2005-02-01

    Lentiviral vectors pseudotyped with G glycoprotein from vesicular stomatitis virus (VSV-G) and baculovirus gp64 are inactivated by human complement. The extent of vector inactivation in serum from individual donors was examined and results showed wide donor-dependent variation in complement sensitivity for VSV-G-pseudotyped lentivectors. Amphotropic envelope (Ampho)-pseudotyped vectors were generally resistant to serum from all donors, while gp64-pseudotyped vectors were inactivated but showed less donor-to-donor variation than VSV-G. In animal sera, the vectors were mostly resistant to inactivation by rodent complement, whereas canine complement caused a moderate reduction in titer. In a novel advance for the lentiviral vector system, human complement-resistant-pseudotyped lentivector particles were produced through incorporation of complement regulatory proteins (CRPs). Decay accelerating factor (DAF)/CD55 provided the most effective protection using this method, while membrane cofactor protein (MCP)/CD46 showed donor-dependent protection and CD59 provided little or no protection against complement inactivation. Unlike previous approaches using CRPs to produce complement-resistant viral vectors, CRP-containing lentivectors particles were generated for this study without engineering the CRP molecules. Thus, through overexpression of native DAF/CD55 in the viral producer cell, an easy method was developed for generation of lentiviral vectors that are almost completely resistant to inactivation by human complement. Production of complement-resistant lentiviral particles is a critical step toward use of these vectors for in vivo gene therapy applications. PMID:15550926

  13. Chemical analysis and hemolytic activity of the fava bean aglycon divicine.

    PubMed

    McMillan, D C; Schey, K L; Meier, G P; Jollow, D J

    1993-01-01

    Divicine is an unstable aglycon metabolite of the fava bean pyrimidine beta-glucoside vicine. Divicine has long been thought to be a mediator of an acute hemolytic crisis, known as favism, in susceptible individuals who ingest fava beans (Vicia faba). However, a recent report has questioned the chemical identity of the divicine that was used in most of the studies on divicine hemotoxicity. The present study was undertaken to examine the hemolytic potential of synthetic divicine. Divicine was synthesized and its identity and purity were confirmed by HPLC, mass spectrometry, and NMR spectroscopy. The stability and redox behavior of divicine, under physiological conditions, were examined by HPLC and cyclic voltammetry. The data indicate that divicine is readily oxidized under aerobic conditions; however, it was sufficiently stable at pH 7.4 to permit its experimental manipulation. When 51Cr-labeled rat erythrocytes were exposed in vitro to the parent glucoside, vicine (5 mM), and then readministered to rats, no decrease in erythrocyte survival was observed. In contrast, erythrocyte survival was dramatically reduced by in vitro exposure to divicine (1.5 mM). These data demonstrate that divicine is a direct-acting hemolytic agent and thus may be a mediator of the hemolytic crisis induced by fava bean ingestion. PMID:8374040

  14. Pulmonary hypertension in hemolytic disorders: pulmonary vascular disease: the global perspective.

    PubMed

    Machado, Roberto F; Gladwin, Mark T

    2010-06-01

    The inherited hemoglobin disorders sickle cell disease and thalassemia are the most common monogenetic disorders worldwide. Pulmonary hypertension is one of the leading causes of morbidity and mortality in adult patients with sickle cell disease and thalassemia, and hemolytic disorders are potentially among the most common causes of pulmonary hypertension. The pathogenesis of pulmonary hypertension in hemolytic disorders is likely multifactorial, including hemolysis, impaired nitric oxide (NO) bioavailability, chronic hypoxemia, chronic thromboembolic disease, chronic liver disease, and asplenia. In contrast to patients with traditional forms of pulmonary arterial hypertension, patients with hemolytic disorders have a mild-to-moderate degree of elevation in mean pulmonary pressures, with mild elevations in pulmonary vascular resistance. The hemodynamic etiology of pulmonary hypertension in these patients is multifactorial and includes pulmonary arterial hypertension, pulmonary venous hypertension, and pulmonary hypertension secondary to a hyperdynamic state. Currently, there are limited data on the effects of any specific treatment modality for pulmonary hypertension in patients with hemolytic disorders. It is likely that maximization of treatment of the primary hemoglobinopathy in all patients and treatment with selective pulmonary vasodilators and antiproliferative agents in patients with pulmonary arterial hypertension would be beneficial. However, there is still a major need for large multinational trials of novel therapies for this patient population. PMID:20522578

  15. Brown recluse spider (Loxosceles reclusa) envenomation leading to acute hemolytic anemia in six adolescents.

    PubMed

    McDade, Jenny; Aygun, Banu; Ware, Russell E

    2010-01-01

    Loxosceles reclusa (brown recluse spider) bites often cause local envenomation reactions; however, acute hemolysis from systemic loxoscelism is rare. To highlight this important diagnostic consideration for unexplained hemolysis in areas endemic for brown recluse spiders, we report on 6 adolescents with acute hemolytic anemia from presumed L reclusa bites. PMID:20006769

  16. Rituximab for immune hemolytic anemia following T- and B-Cell-depleted hematopoietic stem cell transplantation.

    PubMed

    Corti, P; Bonanomi, S; Vallinoto, C; Balduzzi, A; Uderzo, C; Cazzaniga, G; Gaipa, G; Dassi, M; Perseghin, P; Rovelli, A

    2003-01-01

    The treatment of immune-mediated hemolytic anemia (IHA) complicating hematopoietic stem cell transplantation (HSCT) is often unsatisfactory. We report a case of IHA which occurred after T- and B-cell depleted unrelated donor HSCT carried out for mucopolysaccharidosis type I-H (Hurler syndrome) which was successfully treated with anti-CD20+ monoclonal antibody PMID:12486323

  17. Isolation and identification of two hemolytic forms of streptolysin-O.

    PubMed

    Bhakdi, S; Roth, M; Sziegoleit, A; Tranum-Jensen, J

    1984-11-01

    Streptolysin-O was isolated from culture supernatants of group-A beta-hemolytic streptococci (Richards strain) by ammonium sulfate and polyethylene glycol precipitation, DEAE-ion exchange chromatography, preparative isoelectric focusing, and chromatography on Sephacryl S-300. Two forms of the toxin possessing similar hemolytic capacity were identified. The native toxin was a single polypeptide chain devoid of amino sugars with a sedimentation coefficient of 3.9S and a molecular weight of 69,000, and was isoelectric at pH 6.0 to 6.4. Partial degradation of the native toxin occurred during the isolation procedure, yielding a hemolytically active polypeptide with a molecular weight of 57,000 and a pI of 7.0 to 7.5. Both forms of the toxin generated the typical, heterogeneous, open and closed ring-structured channels in erythrocyte membranes. Structural considerations indicated that between 25 and 100 monomer toxin molecules constituted the individual ultrastructurally recognizable channels. Hemolytic titrations indicated that the presence of 70 to 125 toxin molecules per erythrocyte was required to generate an average of one functional lesion per cell. The data are consistent with the concept that one or very few streptolysin-O channels will cause hemolysis. PMID:6500696

  18. Histiocytic Sarcoma Associated with Coombs Negative Acute Hemolytic Anemia: A Rare Presentation

    PubMed Central

    Martin, Stephen C.; Nassiri, Mehdi; Qureshi, Amna; Markel, Troy A.

    2016-01-01

    Histiocytic sarcoma (HS) rarely involves extranodal sites, such as the spleen. We report a unique pediatric case of massive splenomegaly and refractory Coombs negative hemolytic anemia (CNHA) secondary to HS. The CNHA resolved completely after an emergent splenectomy. Next generation sequencing (NGS) revealed novel ASXL1, PTPN11, KIT, and TP53 mutations, unmasking a clonal heterogeneity within the same neoplasm. PMID:27429816

  19. Synthesis, cytotoxicity, and hemolytic activity of 6'-O-substituted dioscin derivatives.

    PubMed

    Li, Wei; Qiu, Zaozao; Wang, Yibing; Zhang, Yichun; Li, Ming; Yu, Jia; Zhang, Lihong; Zhu, Ziyan; Yu, Biao

    2007-12-28

    Dioscin derivatives (1-12) with a variety of substitutions at the 6'-OH of the chacotriosyl residue and the 3',6'-anhydrosaponin derivatives (26, 30, and 32) were synthesized. All these derivatives showed much lower cytotoxicity than that of the parent dioscin, while their hemolytic activities were partially retained depending on the various 6'-O-substitutions. PMID:17945208

  20. Humanized mouse model of glucose 6-phosphate dehydrogenase deficiency for in vivo assessment of hemolytic toxicity

    PubMed Central

    Rochford, Rosemary; Ohrt, Colin; Baresel, Paul C.; Campo, Brice; Sampath, Aruna; Magill, Alan J.; Tekwani, Babu L.; Walker, Larry A.

    2013-01-01

    Individuals with glucose 6-phosphate dehydrogenase (G6PD) deficiency are at risk for the development of hemolytic anemia when given 8-aminoquinolines (8-AQs), an important class of antimalarial/antiinfective therapeutics. However, there is no suitable animal model that can predict the clinical hemolytic potential of drugs. We developed and validated a human (hu)RBC-SCID mouse model by giving nonobese diabetic/SCID mice daily transfusions of huRBCs from G6PD-deficient donors. Treatment of SCID mice engrafted with G6PD-deficient huRBCs with primaquine, an 8-AQ, resulted in a dose-dependent selective loss of huRBCs. To validate the specificity of this model, we tested known nonhemolytic antimalarial drugs: mefloquine, chloroquine, doxycycline, and pyrimethamine. No significant loss of G6PD-deficient huRBCs was observed. Treatment with drugs known to cause hemolytic toxicity (pamaquine, sitamaquine, tafenoquine, and dapsone) resulted in loss of G6PD-deficient huRBCs comparable to primaquine. This mouse model provides an important tool to test drugs for their potential to cause hemolytic toxicity in G6PD-deficient populations. PMID:24101478

  1. Identification of human complement factor H as a chemotactic protein for monocytes.

    PubMed Central

    Nabil, K; Rihn, B; Jaurand, M C; Vignaud, J M; Ripoche, J; Martinet, Y; Martinet, N

    1997-01-01

    We used chromatographic separation to purify to homogeneity a monomeric monocyte chemotactic protein of 150 kDa contained in mesothelioma pleural effusions. It was identified by N-terminal amino acid sequencing and immunoblotting as complement factor H, an inhibitor of the alternative complement pathway. Specific antibodies against factor H inhibited the monocyte chemotactic activity of the purified protein, which was most active at 10 nM. Factor H is a restrictive factor of alternative complement pathway activation. The new chemotactic function assigned to factor H in recruiting monocytes to the mesothelioma site might contribute to malignant cell phagocytosis via the iC3b/complement receptor type 3 pathway. These functions link the humoral and cellular immune systems. PMID:9291108

  2. Low Serum Fetuin-A as a Biomarker to Predict Pneumococcal Necrotizing Pneumonia and Hemolytic Uremic Syndrome in Children

    PubMed Central

    Janapatla, Rajendra Prasad; Hsu, Mei-Hua; Liao, Wan-Ting; Chien, Kun-Yi; Lee, Hao-Yuan; Chiu, Cheng-Hsun

    2016-01-01

    Abstract Streptococcus pneumoniae, a neuraminidase-producing pathogen, can cause invasive pneumococcal disease (IPD) with or without hemolytic uremic syndrome (HUS) in humans. We aimed to identify serum sialoglycoproteins that are targeted by neuraminidases in severe pneumococcal infection. We hypothesized that serum sialoglycoprotein such as fetuin-A can serve as a biomarker to predict IPD or HUS. We constructed serum sialoglycoprotein profiles before and after pneumococcal neuraminidase treatment using liquid chromatography-tandem mass spectrometry (LC-MS/MS), a proteomic approach. An observational study was conducted using clinical data and serum samples from pediatric patients with pneumococcal infection to verify the predictive role of fetuin-A in IPD. Serum fetuin-A levels were determined by enzyme-linked immunosorbent assay. The most abundant serum sialoglycoproteins identified by LC-MS/MS after neuraminidase treatment and peanut lectin capture were immunoglobulins, apolipoproteins, fibrinogens, keratins, complement system proteins, and fetuin-A. Serum fetuin-A levels in the HUS patients were significantly lower (207 ± 80 mg/L, P < 0.001) than in patients with lobar pneumonia (610 ± 190 mg/L) as well as the healthy controls (630 ± 250 mg/L). In comparing HUS with necrotizing pneumonia and lobar pneumonia, the ROC area under the curve was 0.842; a cutoff value of 298 mg/L yielded sensitivity of 92.9% (95% CI: 68.5–98.7%) and specificity of 71.9% (95% CI: 54.6–84.4%). This observational study with validation cohorts of patients with HUS, complicated pneumonia, and lobar pneumonia demonstrates the high performance of low serum fetuin-A levels as a biomarker to predict severe IPD and HUS in children. PMID:27043691

  3. Low Serum Fetuin-A as a Biomarker to Predict Pneumococcal Necrotizing Pneumonia and Hemolytic Uremic Syndrome in Children.

    PubMed

    Janapatla, Rajendra Prasad; Hsu, Mei-Hua; Liao, Wan-Ting; Chien, Kun-Yi; Lee, Hao-Yuan; Chiu, Cheng-Hsun

    2016-03-01

    Streptococcus pneumoniae, a neuraminidase-producing pathogen, can cause invasive pneumococcal disease (IPD) with or without hemolytic uremic syndrome (HUS) in humans.We aimed to identify serum sialoglycoproteins that are targeted by neuraminidases in severe pneumococcal infection. We hypothesized that serum sialoglycoprotein such as fetuin-A can serve as a biomarker to predict IPD or HUS.We constructed serum sialoglycoprotein profiles before and after pneumococcal neuraminidase treatment using liquid chromatography-tandem mass spectrometry (LC-MS/MS), a proteomic approach. An observational study was conducted using clinical data and serum samples from pediatric patients with pneumococcal infection to verify the predictive role of fetuin-A in IPD. Serum fetuin-A levels were determined by enzyme-linked immunosorbent assay.The most abundant serum sialoglycoproteins identified by LC-MS/MS after neuraminidase treatment and peanut lectin capture were immunoglobulins, apolipoproteins, fibrinogens, keratins, complement system proteins, and fetuin-A. Serum fetuin-A levels in the HUS patients were significantly lower (207 ± 80 mg/L, P < 0.001) than in patients with lobar pneumonia (610 ± 190 mg/L) as well as the healthy controls (630 ± 250 mg/L). In comparing HUS with necrotizing pneumonia and lobar pneumonia, the ROC area under the curve was 0.842; a cutoff value of 298 mg/L yielded sensitivity of 92.9% (95% CI: 68.5-98.7%) and specificity of 71.9% (95% CI: 54.6-84.4%).This observational study with validation cohorts of patients with HUS, complicated pneumonia, and lobar pneumonia demonstrates the high performance of low serum fetuin-A levels as a biomarker to predict severe IPD and HUS in children. PMID:27043691

  4. Strategies developed by bacteria and virus for protection from the human complement system.

    PubMed

    Blom, A M

    2004-01-01

    The complement system is an important part of innate immunity providing immediate protection against pathogens without a need for previous exposure. Its importance is clearly shown by the fact that patients lacking complement components suffer from fulminant and recurring infections. Complement is an explosive cascade, and in order to control it there are inhibitors present on every human cell and also circulating in blood. However, many infectious agents have developed strategies to prevent clearance and destruction by complement. Some pathogens simply hijack the host's complement inhibitors, while others are able to produce their own homologues of human inhibitors. Knowledge of these mechanisms on a molecular level may aid development of vaccines and novel therapeutic strategies that would be more specific than the use of antibiotics that, apart from causing resistance problems, also affect the normal flora, the outcome of which could be devastating. In this study the structural requirements and functional consequences of interactions between the major soluble inhibitor of complement C4b-binding protein and Neisseria gonorrhoeae, Bordetella pertussis, Streptococcus pyogenes, Escherichia coli K1, Moraxella catarrhalis and Candida albicans are described. Furthermore, a novel inhibitor produced by Kaposi's sarcoma-associated herpesvirus is identified and characterized in detail: KCP. It is shown that KCP inhibits classical C3-convertase and presents activated complement factors C4b and C3b for destruction by a serine proteinase, factor I. Using molecular modelling and site-directed mutagenesis, it was possible to localize sites on the surface of KCP required for complement inhibition and it is concluded that KCP uses molecular mechanisms identical to human inhibitors. PMID:15276914

  5. Sigma E Regulators Control Hemolytic Activity and Virulence in a Shrimp Pathogenic Vibrio harveyi

    PubMed Central

    Rattanama, Pimonsri; Thompson, Janelle R.; Kongkerd, Natthawan; Srinitiwarawong, Kanchana; Vuddhakul, Varaporn; Mekalanos, John J.

    2012-01-01

    Members of the genus Vibrio are important marine and aquaculture pathogens. Hemolytic activity has been identified as a virulence factor in many pathogenic vibrios including V. cholerae, V. parahaemolyticus, V. alginolyticus, V. harveyi and V. vulnificus. We have used transposon mutagenesis to identify genes involved in the hemolytic activity of shrimp-pathogenic V. harveyi strain PSU3316. Out of 1,764 mutants screened, five mutants showed reduced hemolytic activity on sheep blood agar and exhibited virulence attenuation in shrimp (Litopenaeus vannamei). Mutants were identified by comparing transposon junction sequences to a draft of assembly of the PSU3316 genome. Surprisingly none of the disrupted open reading frames or gene neighborhoods contained genes annotated as hemolysins. The gene encoding RseB, a negative regulator of the sigma factor (σE), was interrupted in 2 out of 5 transposon mutants, in addition, the transcription factor CytR, a threonine synthetase, and an efflux-associated cytoplasmic protein were also identified. Knockout mutations introduced into the rpoE operon at the rseB gene exhibited low hemolytic activity in sheep blood agar, and were 3-to 7-fold attenuated for colonization in shrimp. Comparison of whole cell extracted proteins in the rseB mutant (PSU4030) to the wild-type by 2-D gel electrophoresis revealed 6 differentially expressed proteins, including two down-regulated porins (OmpC-like and OmpN) and an upregulated protease (DegQ) which have been associated with σE in other organisms. Our study is the first report linking hemolytic activity to the σE regulators in pathogenic Vibrio species and suggests expression of this virulence-linked phenotype is governed by multiple regulatory pathways within the V. harveyi. PMID:22384269

  6. Hemolytic activity and solubilizing capacity of raffinose and melezitose fatty acid monoesters prepared by enzymatic synthesis.

    PubMed

    Carvalho, Luis; Morales, Juan C; Pérez-Victoria, José M; Pérez-Victoria, Ignacio

    2015-05-01

    The hemolytic activity and solubilizing capacity of two families of non-reducing trisaccharide fatty acid monoesters have been studied to assess their usefulness as surfactants for pharmaceutical applications. The carbohydrate-based surfactants investigated included homologous series of raffinose and melezitose monoesters bearing C10 to C18 acyl chains prepared by lipase-catalyzed synthesis in organic media. The hemolytic activity was determined in vitro using a static method based on the addition of the surfactants to an erythrocyte suspension and subsequent spectrophotometric determination of the released hemoglobin. The effect of the carbohydrate head group, the acyl chain length and the regioisomeric purity was investigated. In all cases, the carbohydrate monoester surfactants decreased their hemolytic activity (with respect to their critical micelle concentration) when increasing the length of the acyl chain. A very similar behaviour was observed either the carbohydrate head-group (raffinose and melezitose) or regardless of the regioisomeric purity. Interestingly, decanoyl (C10) and lauroyl (C12) monoesters were just marginally hemolytic at their critical micelle concentrations while the longer palmitoyl (C16) and (C18) stearoyl monoesters become hemolytic at concentrations much higher than their respective cmc. The palmitoyl and stearoyl monoesters also displayed higher solubilization capacity than the shorter acyl chain monoesters in a solubilization assay of a hydrophobic dye as a model drug mimic. These results suggest that raffinose and melezitose monoesters with long-chain fatty acids (C16 to C18) are promising surfactants for pharmaceutical applications and could be an alternative to the use of current commercial nonionic polyoxyethylene-based surfactants in parenteral formulations. PMID:25753196

  7. Hereditary Hemolytic Anemia with Human Erythrocyte Pyrimidine 5′-Nucleotidase Deficiency

    PubMed Central

    Valentine, William N.; Fink, Kay; Paglia, Donald E.; Harris, Susan R.; Adams, William S.

    1974-01-01

    A severe deficiency of a red cell pyrimidine 5′-nucleotidase was found to be associated with hereditary hemolytic anemia in four members of three kindreds. The syndrome was characterized by marked increases above normal in red cell basophilic stippling, total nucleotides, and GSH and by a fairly severe deficiency of ribosephosphate pyrophosphokinase (EC 2.7.6.1.). Patient erythrocytes uniquely contained large amounts of pyrimidine 5′-ribonucleotides. In earlier studies, these were erroneously considered to be adenosine phosphates, since all previous investigations of the nucleotides of human red cells and reticulocytes have shown 97% or more to contain adenine. Total nucleotides in patient cells were present in amounts 3-6 times greater than normal, and approximately 80% contained pyrimidine. The ultraviolet spectral curves of deproteinized red cell extracts exhibited a shift in maximum absorbance from the usual 256-257 nm to approximately 266-270 nm, and absorbance at 250, 270, 280, and 290 nm, expressed as a ratio of that at 260 nm, differed greatly from normal. The spectral characteristics of extracts provide the basis of a readily performed screening procedure, which does not require enzyme assay. The nucleotidase activity in deficient red cells assayed less than 14%, and usually less than 10%, of normal and much less in terms of reticulocyte-rich blood, where it was consistently found to be increased. The enzyme has a pH optimum of 7.5-8.0, is inhibited by EDTA, and does not utilize purine 5′-ribonucleotides or β-glycerophosphate as substrates. While comparatively few family members have been available thus far for study, initial data are compatible with an autosomal, recessive mode of transmission of the deficiency. The pyrimidine 5′-ribonucleotides are presumably derived from RNA degradation and, not being diffusible, accumulate when the enzyme catalyzing their dephosphorylation is deficient. It is postulated that the prominent basophilic stippling

  8. NETosing Neutrophils Activate Complement Both on Their Own NETs and Bacteria via Alternative and Non-alternative Pathways

    PubMed Central

    Yuen, Joshua; Pluthero, Fred G.; Douda, David N.; Riedl, Magdalena; Cherry, Ahmed; Ulanova, Marina; Kahr, Walter H. A.; Palaniyar, Nades; Licht, Christoph

    2016-01-01

    Neutrophils deposit antimicrobial proteins, such as myeloperoxidase and proteases on chromatin, which they release as neutrophil extracellular traps (NETs). Neutrophils also carry key components of the complement alternative pathway (AP) such as properdin or complement factor P (CFP), complement factor B (CFB), and C3. However, the contribution of these complement components and complement activation during NET formation in the presence and absence of bacteria is poorly understood. We studied complement activation on NETs and a Gram-negative opportunistic bacterial pathogen Pseudomonas aeruginosa (PA01, PAKwt, and PAKgfp). Here, we show that anaphylatoxin C5a, formyl-methionyl-leucyl-phenylalanine (fMLP) and phorbol myristate acetate (PMA), which activates NADPH oxidase, induce the release of CFP, CFB, and C3 from neutrophils. In response to PMA or P. aeruginosa, neutrophils secrete CFP, deposit it on NETs and bacteria, and induce the formation of terminal complement complexes (C5b–9). A blocking anti-CFP antibody inhibited AP-mediated but not non-AP-mediated complement activation on NETs and P. aeruginosa. Therefore, NET-mediated complement activation occurs via both AP- and non AP-based mechanisms, and AP-mediated complement activation during NETosis is dependent on CFP. These findings suggest that neutrophils could use their “AP tool kit” to readily activate complement on NETs and Gram-negative bacteria, such as P. aeruginosa, whereas additional components present in the serum help to fix non-AP-mediated complement both on NETs and bacteria. This unique mechanism may play important roles in host defense and help to explain specific roles of complement activation in NET-related diseases. PMID:27148258

  9. NETosing Neutrophils Activate Complement Both on Their Own NETs and Bacteria via Alternative and Non-alternative Pathways.

    PubMed

    Yuen, Joshua; Pluthero, Fred G; Douda, David N; Riedl, Magdalena; Cherry, Ahmed; Ulanova, Marina; Kahr, Walter H A; Palaniyar, Nades; Licht, Christoph

    2016-01-01

    Neutrophils deposit antimicrobial proteins, such as myeloperoxidase and proteases on chromatin, which they release as neutrophil extracellular traps (NETs). Neutrophils also carry key components of the complement alternative pathway (AP) such as properdin or complement factor P (CFP), complement factor B (CFB), and C3. However, the contribution of these complement components and complement activation during NET formation in the presence and absence of bacteria is poorly understood. We studied complement activation on NETs and a Gram-negative opportunistic bacterial pathogen Pseudomonas aeruginosa (PA01, PAKwt, and PAKgfp). Here, we show that anaphylatoxin C5a, formyl-methionyl-leucyl-phenylalanine (fMLP) and phorbol myristate acetate (PMA), which activates NADPH oxidase, induce the release of CFP, CFB, and C3 from neutrophils. In response to PMA or P. aeruginosa, neutrophils secrete CFP, deposit it on NETs and bacteria, and induce the formation of terminal complement complexes (C5b-9). A blocking anti-CFP antibody inhibited AP-mediated but not non-AP-mediated complement activation on NETs and P. aeruginosa. Therefore, NET-mediated complement activation occurs via both AP- and non AP-based mechanisms, and AP-mediated complement activation during NETosis is dependent on CFP. These findings suggest that neutrophils could use their "AP tool kit" to readily activate complement on NETs and Gram-negative bacteria, such as P. aeruginosa, whereas additional components present in the serum help to fix non-AP-mediated complement both on NETs and bacteria. This unique mechanism may play important roles in host defense and help to explain specific roles of complement activation in NET-related diseases. PMID:27148258

  10. Scabies mite inactive serine proteases are potent inhibitors of the human complement lectin pathway.

    PubMed

    Reynolds, Simone L; Pike, Robert N; Mika, Angela; Blom, Anna M; Hofmann, Andreas; Wijeyewickrema, Lakshmi C; Kemp, Dave; Fischer, Katja

    2014-05-01

    Scabies is an infectious skin disease caused by the mite Sarcoptes scabiei and has been classified as one of the six most prevalent epidermal parasitic skin diseases infecting populations living in poverty by the World Health Organisation. The role of the complement system, a pivotal component of human innate immunity, as an important defence against invading pathogens has been well documented and many parasites have an arsenal of anti-complement defences. We previously reported on a family of scabies mite proteolytically inactive serine protease paralogues (SMIPP-Ss) thought to be implicated in host defence evasion. We have since shown that two family members, SMIPP-S D1 and I1 have the ability to bind the human complement components C1q, mannose binding lectin (MBL) and properdin and are capable of inhibiting all three human complement pathways. This investigation focused on inhibition of the lectin pathway of complement activation as it is likely to be the primary pathway affecting scabies mites. Activation of the lectin pathway relies on the activation of MBL, and as SMIPP-S D1 and I1 have previously been shown to bind MBL, the nature of this interaction was examined using binding and mutagenesis studies. SMIPP-S D1 bound MBL in complex with MBL-associated serine proteases (MASPs) and released the MASP-2 enzyme from the complex. SMIPP-S I1 was also able to bind MBL in complex with MASPs, but MASP-1 and MASP-2 remained in the complex. Despite these differences in mechanism, both molecules inhibited activation of complement components downstream of MBL. Mutagenesis studies revealed that both SMIPP-Ss used an alternative site of the molecule from the residual active site region to inhibit the lectin pathway. We propose that SMIPP-Ss are potent lectin pathway inhibitors and that this mechanism represents an important tool in the immune evasion repertoire of the parasitic mite and a potential target for therapeutics. PMID:24854034

  11. RSM optimized Moringa oleifera peel extract for green synthesis of M. oleifera capped palladium nanoparticles with antibacterial and hemolytic property.

    PubMed

    Surendra, T V; Roopan, Selvaraj Mohana; Arasu, Mariadhas Valan; Al-Dhabi, Naif Abdullah; Rayalu, G Mokesh

    2016-09-01

    Palladium nanoparticles (Pd NPs) are the very good catalytic agents in many coupling reactions, also these are very well biological agents against bacteria and fungus. M. oleifera capped Pd NPs were synthesized from microwave assisted methanolic extract of M. oleifera peel. To optimize the extraction process RSM (Response Surface Methodology) was applied. To get a good extraction yield BBD (Box-Behnken Design) was employed. The better optimized conditions for the extraction was found as 400W, 25mL of CH3OH at 65°C for 2min. We observed 61.66mg of extract yield from this method. Eco-friendly M. oleifera capped Pd NPs were synthesized using M. oleifera peel extract and confirmed using the different characterization techniques like UV- Vis spectroscopy, XRD, SEM and HR-TEM analysis. We found the size of the M. oleifera capped Pd NPs nanoparticles as 27±2nm and shape of the particles as spherical through the TEM analysis. M. oleifera capped Pd NPs exhibits good antibacterial activity against S. aureus (Staphylococcus aureus) and E. coli (Escherichia coli) bacterial strains and we found the zone inhibition as 0.6 and 0.7mm. The synthesized M. oleifera capped Pd NPs are screened for hemolytic activity and it proved the M. oleifera capped Pd NPs are non-toxic on RBCs cells. PMID:27474786

  12. Biological effects of short-term, high-concentration exposure to methyl isocyanate. VI. In vitro and in vivo complement activation studies

    SciTech Connect

    Kolb, W.P.; Savary, J.R.; Troup, C.M.; Dodd, D.E.; Tamerius, J.D.

    1987-06-01

    The ability of MIC to induce complement activation in vitro and in vivo was investigated. For the in vitro studies, both human and guinea pig serum or EDTA-plasma samples were exposed to 1167 to 1260 ppm MIC vapor for 15 min at room temperature. The human serum samples exposed to MIC showed significant reduction in Factor B, C2, C4, C3, C5, and total hemolytic complement CH/sub 50/ activity levels. The C3, C5, and CH/sub 50/ functional activities in guinea pig serum were more sensitive to MIC-mediated reduction than the corresponding activity reductions observed in the human serum samples. The human and single guinea pig EDTA-plasma samples exposed to MIC vapor showed no evidence of C3 consumption but did show significant reductions in CH/sub 50/ levels. Thus, MIC vapor was able to active, and thereby reduce serum complement C3 activity in vitro by a complement-dependent process. For the in vivo studies, five pairs of guinea pigs were exposed to 644 to 702 ppm MIC vapor until one of the pair died (11-15 min). MIC exposure was then discontinued, the surviving guinea pig was sacrificed, and EDTA-plasma was obtained from both animals and analyzed for complement consumption. Clear evidence was obtained to indicate that complement activation had occurred in these animals exposed to MIC for 11 to 15 min. In addition, the complement activation profile observed in these guinea pigs was qualitatively similar to that seen in the guinea pig serum samples exposed to MIC vapor in vitro. The total protein concentration present in plasma samples obtained from guinea pigs that had died from MIC exposure was elevated significantly. The possible contribution of complement activation to the fatal reaction(s) observed in these MIC-treated animals is discussed.

  13. Phylogenetic aspects of the complement system.

    PubMed

    Zarkadis, I K; Mastellos, D; Lambris, J D

    2001-01-01

    During evolution two general systems of immunity have emerged: innate or, natural immunity and adaptive (acquired), or specific immunity. The innate system is phylogenetically older and is found in some form in all multicellular organisms, whereas the adaptive system appeared about 450 million years ago and is found in all vertebrates except jawless fish. The complement system in higher vertebrates plays an important role as an effector of both the innate and the acquired immune response, and also participates in various immunoregulatory processes. In lower vertebrates complement is activated by the alternative and lectin pathways and is primarily involved in the opsonization of foreign material. The Agnatha (the most primitive vertebrate species) possess the alternative and lectin pathways while cartilaginous fish are the first species in which the classical pathway appears following the emergence of immunoglobulins. The rest of the poikilothermic species, ranging from teleosts to reptilians, appear to contain a well-developed complement system resembling that of the homeothermic vertebrates. It seems that most of the complement components have appeared after the duplication of primordial genes encoding C3/C4/C5, fB/C2, C1s/C1r/MASP-1/MASP-2, and C6/C7/C8/C9 molecules, in a process that led to the formation of distinct activation pathways. However, unlike homeotherms, several species of poikilotherms (e.g. trout) have recently been shown to possess multiple forms of complement components (C3, factor B) that are structurally and functionally more diverse than those of higher vertebrates. We hypothesize that this remarkable diversity has allowed these animals to expand their innate capacity for immune recognition and response. Recent studies have also indicated the possible presence of complement receptors in protochordates and lower vertebrates. In conclusion, there is considerable evidence suggesting that the complement system is present in the entire lineage of

  14. TNT003, an inhibitor of the serine protease C1s, prevents complement activation induced by cold agglutinins.

    PubMed

    Shi, Ju; Rose, Eileen L; Singh, Andrew; Hussain, Sami; Stagliano, Nancy E; Parry, Graham C; Panicker, Sandip

    2014-06-26

    Activation of the classical pathway (CP) of complement is often associated with autoimmune disorders in which disease pathology is linked to the presence of an autoantibody. One such disorder is cold agglutinin disease (CAD), an autoimmune hemolytic anemia in which autoantibodies (cold agglutinins) bind to red blood cells (RBCs) at low temperatures. Anemia occurs as a result of autoantibody-mediated CP activation on the surface of the erythrocyte, leading to the deposition of complement opsonins that drive extravascular hemolysis in the liver. Here we test the effects of TNT003, a mouse monoclonal antibody targeting the CP-specific serine protease C1s, on CP activity induced by cold agglutinins on human RBCs. We collected 40 individual CAD patient samples and showed that TNT003 prevented cold agglutinin-mediated deposition of complement opsonins that promote phagocytosis of RBCs. Furthermore, we show that by preventing CP activation, TNT003 also prevents cold agglutinin-driven generation of anaphylatoxins. Finally, we provide evidence that CP activity in CAD patients terminates prior to activation of the terminal cascade, supporting the hypothesis that the primary route of RBC destruction in these patients occurs via extravascular hemolysis. Our results support the development of a CP inhibitor for the treatment of CAD. PMID:24695853

  15. Complement and the severity of pulmonary failure.

    PubMed

    Weigelt, J A; Chenoweth, D E; Borman, K R; Norcross, J F

    1988-07-01

    Complement-induced granulocyte aggregation is suspected as a cause of the adult respiratory distress syndrome. Quantifying the lung damage in these patients is difficult, and complement levels combined with clinical parameters of oxygenation might help define the severity of pulmonary deterioration. Forty-five high-risk patients, selected by arterial blood gas criteria, had their pulmonary insult related to C3a and C5a levels. Patients were stratified by pulmonary shunt, alveolar-arterial oxygen gradient, and radiographic findings into two categories of severity: pulmonary dysfunction, a milder insult, and ARDS, a major aberration in pulmonary function. The clinical assignment of a diagnostic category required at least 96 hours of monitoring. During this 96-hour period, multiple complement levels were obtained. These complement levels were then compared in pulmonary dysfunction and ARDS patients. ARDS patients had significantly higher C3a and C5a values after the patients were selected as high risk. These results suggest that the amount of complement activated in patients with incipient respiratory failure correlates with the severity of eventual pulmonary insult. The use of arterial blood gases and C3a and C5a levels should allow better and earlier definition of patients at risk for ARDS. PMID:3260964

  16. Platelets and the complement cascade in atherosclerosis

    PubMed Central

    Patzelt, Johannes; Verschoor, Admar; Langer, Harald F.

    2015-01-01

    Atherosclerosis and its late sequels are still the number one cause of death in western societies. Platelets are a driving force not only during the genesis of atherosclerosis, but especially in its late stages, as evidenced by complications such as arterial thrombosis, myocardial infarction, and ischemic stroke. Atherosclerosis is increasingly recognized as an inflammatory disease, influenced by various immune mechanisms. The complement system is part of our innate immune system, and its diverse roles in atherosclerosis have become evident over the past years. In this review we identify points of intersection between platelets and the complement system and discuss their relevance for atherosclerosis. Specifically, we will focus on roles for platelets in the onset as well as progression of the disease, a possible dual role for complement in the genesis and development of atherosclerosis, and review emerging literature revealing previously unrecognized cross-talk between platelets and the complement system and discuss its possible impact for atherosclerosis. Finally, we identify limitations of current research approaches and discuss perspectives of complement modulation in the control of the disease. PMID:25784879

  17. Early Terminal Complement Blockade and C6 Deficiency Are Protective in Enterohemorrhagic Escherichia coli-Infected Mice.

    PubMed

    Arvidsson, Ida; Rebetz, Johan; Loos, Sebastian; Herthelius, Maria; Kristoffersson, Ann-Charlotte; Englund, Elisabet; Chromek, Milan; Karpman, Diana

    2016-08-15

    Complement activation occurs during enterohemorrhagic Escherichia coli (EHEC) infection and may exacerbate renal manifestations. In this study, we show glomerular C5b-9 deposits in the renal biopsy of a child with EHEC-associated hemolytic uremic syndrome. The role of the terminal complement complex, and its blockade as a therapeutic modality, was investigated in a mouse model of E. coli O157:H7 infection. BALB/c mice were treated with monoclonal anti-C5 i.p. on day 3 or 6 after intragastric inoculation and monitored for clinical signs of disease and weight loss for 14 d. All infected untreated mice (15 of 15) or those treated with an irrelevant Ab (8 of 8) developed severe illness. In contrast, only few infected mice treated with anti-C5 on day 3 developed symptoms (three of eight, p < 0.01 compared with mice treated with the irrelevant Ab on day 3) whereas most mice treated with anti-C5 on day 6 developed symptoms (six of eight). C6-deficient C57BL/6 mice were also inoculated with E. coli O157:H7 and only 1 of 14 developed disease, whereas 10 of 16 wild-type mice developed weight loss and severe disease (p < 0.01). Complement activation via the terminal pathway is thus involved in the development of disease in murine EHEC infection. Early blockade of the terminal complement pathway, before the development of symptoms, was largely protective, whereas late blockade was not. Likewise, lack of C6, and thereby deficient terminal complement complex, was protective in murine E. coli O157:H7 infection. PMID:27421478

  18. Relative Role of Genetic Complement Abnormalities in Sporadic and Familial aHUS and Their Impact on Clinical Phenotype

    PubMed Central

    Caprioli, Jessica; Bresin, Elena; Mossali, Chiara; Pianetti, Gaia; Gamba, Sara; Daina, Erica; Fenili, Chiara; Castelletti, Federica; Sorosina, Annalisa; Piras, Rossella; Donadelli, Roberta; Maranta, Ramona; van der Meer, Irene; Conway, Edward M.; Zipfel, Peter F.; Goodship, Timothy H.; Remuzzi, Giuseppe

    2010-01-01

    Background and objectives: Hemolytic uremic syndrome (HUS) is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and renal impairment. Most childhood cases are caused by Shiga toxin–producing bacteria. The other form, atypical HUS (aHUS), accounts for 10% of cases and has a poor prognosis. Genetic complement abnormalities have been found in aHUS. Design, setting, participants, and measurements: We screened 273 consecutive patients with aHUS for complement abnormalities and studied their role in predicting clinical phenotype and response to treatment. We compared mutation frequencies and localization and clinical outcome in familial (82) and sporadic (191) cases. Results: In >70% of sporadic and familial cases, gene mutations, disease-associated factor H (CFH) polymorphisms, or anti-CFH autoantibodies were found. Either mutations or CFH polymorphisms were also found in the majority of patients with secondary aHUS, suggesting a genetic predisposition. Familial cases showed a higher prevalence of mutations in SCR20 of CFH and more severe disease than sporadic cases. Patients with CFH or THBD (thrombomodulin) mutations had the earliest onset and highest mortality. Membrane-cofactor protein (MCP) mutations were associated with the best prognosis. Plasma therapy induced remission in 55 to 80% of episodes in patients with CFH, C3, or THBD mutations or autoantibodies, whereas patients with CFI (factor I) mutations were poor responders. aHUS recurred frequently after kidney transplantation except for patients with MCP mutations. Conclusions: Results underline the need of genetic screening for all susceptibility factors as part of clinical management of aHUS and for identification of patients who could safely benefit from kidney transplant. PMID:20595690

  19. Supramolecular Control over Split-Luciferase Complementation.

    PubMed

    Bosmans, Ralph P G; Briels, Jeroen M; Milroy, Lech-Gustav; de Greef, Tom F A; Merkx, Maarten; Brunsveld, Luc

    2016-07-25

    Supramolecular split-enzyme complementation restores enzymatic activity and allows for on-off switching. Split-luciferase fragment pairs were provided with an N-terminal FGG sequence and screened for complementation through host-guest binding to cucurbit[8]uril (Q8). Split-luciferase heterocomplex formation was induced in a Q8 concentration dependent manner, resulting in a 20-fold upregulation of luciferase activity. Supramolecular split-luciferase complementation was fully reversible, as revealed by using two types of Q8 inhibitors. Competition studies with the weak-binding FGG peptide revealed a 300-fold enhanced stability for the formation of the ternary heterocomplex compared to binding of two of the same fragments to Q8. Stochiometric binding by the potent inhibitor memantine could be used for repeated cycling of luciferase activation and deactivation in conjunction with Q8, providing a versatile module for in vitro supramolecular signaling networks. PMID:27356091

  20. Complement activation in discordant hepatic xenotransplantation.

    PubMed

    Tector, A J; Chen, X; Soderland, C; Tchervenkov, J I

    1998-11-01

    Little is known about hyperacute rejection in hepatic xenotransplantation. Information from clinical xenoperfusions suggests that the liver may be rejected by a mechanism less vigorous than either kidney or heart xenografts. We used the in vitro model of porcine hepatic sinusoidal endothelial cells (PHEC) incubated with either complement replete or deficient human serum to determine the relative roles of the classical and alternate pathways of complement in the immediate response to hepatic xenotransplantation. Our results suggest that either the classical or alternate pathways are capable of independently activating the complement cascade upon exposure to the porcine hepatic sinusoidal endothelium. Our results also imply that either pathway alone is capable of initiating similar degrees of injury as the entire cascade. PMID:9915253

  1. Applying complement therapeutics to rare diseases.

    PubMed

    Reis, Edimara S; Mastellos, Dimitrios C; Yancopoulou, Despina; Risitano, Antonio M; Ricklin, Daniel; Lambris, John D

    2015-12-01

    Around 350 million people worldwide suffer from rare diseases. These may have a genetic, infectious, or autoimmune basis, and several include an inflammatory component. Launching of effective treatments can be very challenging when there is a low disease prevalence and limited scientific insights into the disease mechanisms. As a key trigger of inflammatory processes, complement has been associated with a variety of diseases and has become an attractive therapeutic target for conditions involving inflammation. In view of the clinical experience acquired with drugs licensed for the treatment of rare diseases such as hereditary angioedema and paroxysmal nocturnal hemoglobinuria, growing evidence supports the safety and efficacy of complement therapeutics in restoring immune balance and preventing aggravation of clinical outcomes. This review provides an overview of the candidates currently in the pharmaceutical pipeline with potential to treat orphan diseases and discusses the molecular mechanisms triggered by complement involved with the disease pathogenesis. PMID:26341313

  2. Investigation of whether the acute hemolysis associated with Rho(D) immune globulin intravenous (human) administration for treatment of immune thrombocytopenic purpura is consistent with the acute hemolytic transfusion reaction model

    PubMed Central

    Gaines, Ann Reed; Lee-Stroka, Hallie; Byrne, Karen; Scott, Dorothy E.; Uhl, Lynne; Lazarus, Ellen; Stroncek, David F.

    2012-01-01

    BACKGROUND Immune thrombocytopenic purpura and secondary thrombocytopenia patients treated with Rho(D) immune globulin intravenous (human; anti-D IGIV) have experienced acute hemolysis, which is inconsistent with the typical presentation of extravascular hemolysis—the presumed mechanism of action of anti-D IGIV. Although the mechanism of anti-D-IGIV–associated acute hemolysis has not been established, the onset, signs/symptoms, and complications appear consistent with the intravascular hemolysis of acute hemolytic transfusion reactions (AHTRs). In transfusion medicine, the red blood cell (RBC) antigen-antibody incompatibility(-ies) that precipitate AHTRs can be detected in vitro with compatibility testing. Under the premise that anti-D-IGIV–associated acute hemolysis results from RBC antigen-antibody–mediated complement activation, this study evaluated whether the incompatibility(-ies) could be detected in vitro with a hemolysin assay, which would support the AHTR model as the hemolytic mechanism. STUDY DESIGN AND METHODS Seven anti-D IGIV lots were tested to determine the RBC antibody identities in those lots, including four lots that had been implicated in acute hemolytic episodes. Hemolysin assays were performed that tested each of 73 RBC specimens against each lot, including the RBCs of one patient who had experienced acute hemolysis after anti-D IGIV administration. RESULTS Only two anti-D IGIV lots contained RBC antibodies beyond those expected. No hemolysis endpoint was observed in any of the hemolysin assays. CONCLUSION Although the findings did not support the AHTR model, the results are reported to contribute knowledge about the mechanism of anti-D-IGIV–associated acute hemolysis and to prompt continued investigation into cause(s), prediction, and prevention of this potentially serious adverse event. PMID:19220820

  3. The extracellular RNA complement of Escherichia coli

    PubMed Central

    Ghosal, Anubrata; Upadhyaya, Bimal Babu; Fritz, Joëlle V; Heintz-Buschart, Anna; Desai, Mahesh S; Yusuf, Dilmurat; Huang, David; Baumuratov, Aidos; Wang, Kai; Galas, David; Wilmes, Paul

    2015-01-01

    The secretion of biomolecules into the extracellular milieu is a common and well-conserved phenomenon in biology. In bacteria, secreted biomolecules are not only involved in intra-species communication but they also play roles in inter-kingdom exchanges and pathogenicity. To date, released products, such as small molecules, DNA, peptides, and proteins, have been well studied in bacteria. However, the bacterial extracellular RNA complement has so far not been comprehensively characterized. Here, we have analyzed, using a combination of physical characterization and high-throughput sequencing, the extracellular RNA complement of both outer membrane vesicle (OMV)-associated and OMV-free RNA of the enteric Gram-negative model bacterium Escherichia coli K-12 substrain MG1655 and have compared it to its intracellular RNA complement. Our results demonstrate that a large part of the extracellular RNA complement is in the size range between 15 and 40 nucleotides and is derived from specific intracellular RNAs. Furthermore, RNA is associated with OMVs and the relative abundances of RNA biotypes in the intracellular, OMV and OMV-free fractions are distinct. Apart from rRNA fragments, a significant portion of the extracellular RNA complement is composed of specific cleavage products of functionally important structural noncoding RNAs, including tRNAs, 4.5S RNA, 6S RNA, and tmRNA. In addition, the extracellular RNA pool includes RNA biotypes from cryptic prophages, intergenic, and coding regions, of which some are so far uncharacterised, for example, transcripts mapping to the fimA-fimL and ves-spy intergenic regions. Our study provides the first detailed characterization of the extracellular RNA complement of the enteric model bacterium E. coli. Analogous to findings in eukaryotes, our results suggest the selective export of specific RNA biotypes by E. coli, which in turn indicates a potential role for extracellular bacterial RNAs in intercellular communication. PMID:25611733

  4. Using an in vitro xenoantibody-mediated complement-dependent cytotoxicity model to evaluate the complement inhibitory activity of the peptidic C3 inhibitor Cp40

    PubMed Central

    Wang, Junxiang; Wang, Lu; Xiang, Ying; Ricklin, Daniel; Lambris, John D.; Chen, Gang

    2016-01-01

    Simple and reliable methods for evaluating the inhibitory effects of drug candidates on complement activation are essential for preclinical development. Here, using an immortalized porcine aortic endothelial cell line (iPEC) as target, we evaluated the feasibility and effectiveness of an in vitro xenoantibody-mediated complement-dependent cytotoxicity (CDC) model for evaluating the complement inhibitory activity of Cp40, a potent analog of the peptidic C3 inhibitor compstatin. The binding of human xenoantibodies to iPECs led to serum dilution-dependent cell death. Pretreatment of the human serum with Cp40 almost completely inhibited the deposition of C3 fragments and C5b-9 on the cells, resulting in a dose-dependent inhibition of CDC against the iPECs. Using the same method to compare the effects of Cp40 on complement activation in humans, rhesus and cynomolgus monkeys, we found that the inhibitory patterns were similar overall. Thus, the in vitro xenoantibody-mediated CDC assay may have considerable potential for future clinical use. PMID:26548839

  5. Never make assumptions: the complicated role of complement in urinary tract infections.

    PubMed

    Thurman, Joshua M; Nemenoff, Raphael A

    2016-09-01

    Complement activation can cause tissue inflammation and injury, and complement-inhibitory drugs are effective treatments for several inflammatory diseases. The complement cascade is part of the body's defense against bacteria and other pathogens, however, and a major concern regarding inhibition of this system is that it may increase the risk for infection. Now, a study by Choudhry et al. demonstrates that blockade of signaling at one of the C5a receptors (C5a receptor 1 [C5aR1]) reduces renal fibrosis in a mouse model of urinary tract infection with Escherichia coli. Surprisingly, C5aR1 blockade was also associated with faster clearance of the infection. The results of this study demonstrate that C5a-a highly proinflammatory molecule-reduces bacterial killing by macrophages. Other recent studies have also shown that C5a impairs the elimination of tumor cells by the immune system. These data indicate that complement inhibition may have some unexpected benefits. These results also demonstrate, however, that the complement cascade probably has physiologic functions that have yet to be discovered. PMID:27521106

  6. The sensitivity to complement of strains of Escherichia coli related to their K antigens

    PubMed Central

    Glynn, A. A.; Howard, C. J.

    1970-01-01

    We have confirmed that K antigens influence the sensitivity to complement of strains of Escherichia coli. Resistant strains bound more polycation and by inference therefore had a higher surface negative charge than sensitive strains. Extracts containing K antigen non-specifically inhibited red cell agglutination and this inhibitory activity was roughly proportional to complement resistance. All of five resistant strains became more sensitive to complement when grown at unusual temperatures and extracts from them then had less inhibitory activity. In four strains of serotype O6 K13 complement resistance was proportional to K antigen content measured by immunodiffusion. However, purified K antigen from a resistant strain (WF82) had much greater agglutination inhibiting activity weight for weight than purified K antigen from a sensitive strain (WF96). In experiments with 125I-labelled haemolysin K antigens decreased the binding of both IgG and IgM antibodies and also directly reduced complement activity. The mechanisms of action of K antigens and their relation to virulence are discussed. ImagesFIG. 4FIG. 12 PMID:4986073

  7. The complement system and toll-like receptors as integrated players in the pathophysiology of atherosclerosis.

    PubMed

    Hovland, Anders; Jonasson, Lena; Garred, Peter; Yndestad, Arne; Aukrust, Pål; Lappegård, Knut T; Espevik, Terje; Mollnes, Tom E

    2015-08-01

    Despite recent medical advances, atherosclerosis is a global burden accounting for numerous deaths and hospital admissions. Immune-mediated inflammation is a major component of the atherosclerotic process, but earlier research focus on adaptive immunity has gradually switched towards the role of innate immunity. The complement system and toll-like receptors (TLRs), and the crosstalk between them, may be of particular interest both with respect to pathogenesis and as therapeutic targets in atherosclerosis. Animal studies indicate that inhibition of C3a and C5a reduces atherosclerosis. In humans modified LDL-cholesterol activate complement and TLRs leading to downstream inflammation, and histopathological studies indicate that the innate immune system is present in atherosclerotic lesions. Moreover, clinical studies have demonstrated that both complement and TLRs are upregulated in atherosclerotic diseases, although interventional trials have this far been disappointing. However, based on recent research showing an intimate interplay between complement and TLRs we propose a model in which combined inhibition of both complement and TLRs may represent a potent anti-inflammatory therapeutic approach to reduce atherosclerosis. PMID:26086357

  8. Different Host Complement Systems and Their Interactions with Saliva from Lutzomyia longipalpis (Diptera, Psychodidae) and Leishmania infantum Promastigotes

    PubMed Central

    Mendes-Sousa, Antonio Ferreira; Nascimento, Alexandre Alves Sousa; Queiroz, Daniel Costa; Vale, Vladimir Fazito; Fujiwara, Ricardo Toshio; Araújo, Ricardo Nascimento; Pereira, Marcos Horácio; Gontijo, Nelder Figueiredo

    2013-01-01

    Background Lutzomyia longipalpis is the vector of Leishmania infantum in the New World, and its saliva inhibits classical and alternative human complement system pathways. This inhibition is important in protecting the insect´s midgut from damage by the complement. L. longipalpis is a promiscuous blood feeder and must be protected against its host’s complement. The objective of this study was to investigate the action of salivary complement inhibitors on the sera of different host species, such as dogs, guinea pigs, rats and chickens, at a pH of 7.4 (normal blood pH) and 8.15 (the midgut pH immediately after a blood meal). We also investigated the role of the chicken complement system in Leishmania clearance in the presence and absence of vector saliva. Results The saliva was capable of inhibiting classical pathways in dogs, guinea pigs and rats at both pHs. The alternative pathway was not inhibited except in dogs at a pH of 8.15. The chicken classical pathway was inhibited only by high concentrations of saliva and it was better inhibited by the midgut contents of sand flies. Neither the saliva nor the midgut contents had any effect on the avian alternative pathway. Fowl sera killed L. infantum promastigotes, even at a low concentration (2%), and the addition of L. longipalpis saliva did not protect the parasites. The high body temperature of chickens (40°C) had no effect on Leishmania viability during our assays. Conclusion Salivary inhibitors act in a species-specific manner. It is important to determine their effects in the natural hosts of Leishmania infantum because they act on canid and rodent complements but not on chickens (which do not harbour the parasite). Moreover, we concluded that the avian complement system is the probable mechanism through which chickens eliminate Leishmania and that their high body temperature does not influence this parasite. PMID:24255715

  9. [Hemolytic activity of venoms from snakes of the genera Bothrop, Lachesis, Crotalus, and Micrurus (Serpentes: Viperidae and Elapidae].

    PubMed

    Martínez Cadillo, E; Bonilla Ferreyra, C; Zvealeta, A

    1991-11-01

    Hemolytic activity of eight Peruvian snake venoms from the families Viperidae and Elapidae (Bothrops atrox, B. pictus, B. hyoprorus, B. bilineatus, B. neuwedii, Lachesis m. muta, Crotalus d. terrificus, Micrurus tschudi), and three Brazilian viperids (B. jararacussu, B. alternatus and C. d. collilineatus) is described. None of the venoms caused direct lysis on washed human erythrocytes. However, all of them caused indirect hemolysis provided that the incubation medium contains an exogenous source of lecithin. Venom of Micrurus tschudi was the most hemolytic (HD50 2.8 ug/ml) while that of B. bilineatus was the least (HD50 681.3 ug/ml). Only six of eleven venoms showed parallel curves of hemolytic activity, and the HD50 varied from 198 to 681 ug/ml and the following decreasing order of hemolytic activity was obtained: L. muta, C. d. terrificus, C. d. collilineatus, B. hyoprorus, B. bilineatus, B. alternatus. PMID:1844159

  10. Regulation of Complement Dependent Cytotoxicity by TGF-β-induced Epithelial-Mesenchymal Transition

    PubMed Central

    Goswami, Moloy T.; Reka, Ajaya Kumar; Kurapati, Himabindu; Kaza, Viritha; Chen, Jun; Standiford, Theodore J; Keshamouni, Venkateshwar G.

    2015-01-01

    The process of Epithelial-mesenchymal transition (EMT), in addition to being an initiating event for tumor metastasis, is implicated in conferring several clinically relevant properties to disseminating cancer cells. These include stem cell like properties, resistance to targeted therapies and ability to evade immune surveillance. Enrichment analysis of gene expression changes during TGF-β induced EMT in lung cancer cells identified complement cascade as one of the significantly enriched pathway. Further analysis of the genes in the complement pathway revealed an increase in the expression of complement inhibitors and a decrease in the expression of proteins essential for complement activity. In this study, we tested whether EMT confers resistance to complement-dependent cytotoxicity (CDC) in lung cancer cells and promotes tumor progression. CD59 is a potent inhibitor of membrane attack complex that mediates complement-dependent cell lysis. We observed a significant increase in the CD59 expression on the surface of cells after TGF-β-induced EMT. Furthermore, CD59 knock down restored susceptibility of cells undergoing EMT to Cetuximab-mediated CDC. TGF-β-induced CD59 expression during EMT is dependent on Smad3 but not Smad2. ChIP analysis confirmed that Smad3 directly binds to the CD59 promoter. Stable knock-down of CD59 in A549 cells inhibited experimental metastasis. These results demonstrate that TGF-β-induced EMT and CD59 expression confers an immune evasive mechanism to disseminating tumor cells facilitating tumor progression. Together, our data demonstrates that CD59 inhibition may serve as an adjuvant to enhance the efficacy of antibody-mediated therapies, as well as to inhibit metastasis in lung cancer. PMID:26148233

  11. Regulation of complement-dependent cytotoxicity by TGF-β-induced epithelial-mesenchymal transition.

    PubMed

    Goswami, M T; Reka, A K; Kurapati, H; Kaza, V; Chen, J; Standiford, T J; Keshamouni, V G

    2016-04-14

    The process of epithelial-mesenchymal transition (EMT), in addition to being an initiating event for tumor metastasis, is implicated in conferring several clinically relevant properties to disseminating cancer cells. These include stem cell-like properties, resistance to targeted therapies and ability to evade immune surveillance. Enrichment analysis of gene expression changes during transforming growth factor-β (TGF-β)-induced EMT in lung cancer cells identified complement cascade as one of the significantly enriched pathway. Further analysis of the genes in the complement pathway revealed an increase in the expression of complement inhibitors and a decrease in the expression of proteins essential for complement activity. In this study, we tested whether EMT confers resistance to complement-dependent cytotoxicity (CDC) in lung cancer cells and promotes tumor progression. CD59 is a potent inhibitor of membrane attack complex that mediates complement-dependent cell lysis. We observed a significant increase in the CD59 expression on the surface of cells after TGF-β-induced EMT. Furthermore, CD59 knockdown restored susceptibility of cells undergoing EMT to cetuximab-mediated CDC. TGF-β-induced CD59 expression during EMT is dependent on Smad3 but not on Smad2. Chromatin immunoprecipitation analysis confirmed that Smad3 directly binds to the CD59 promoter. Stable knockdown of CD59 in A549 cells inhibited experimental metastasis. These results demonstrate that TGF-β-induced EMT and CD59 expression confers an immune-evasive mechanism to disseminating tumor cells facilitating tumor progression. Together, our data demonstrates that CD59 inhibition may serve as an adjuvant to enhance the efficacy of antibody-mediated therapies, as well as to inhibit metastasis in lung cancer. PMID:26148233

  12. Painting factor H onto mesenchymal stem cells protects the cells from complement- and neutrophil-mediated damage.

    PubMed

    Li, Yan; Qiu, Wen; Zhang, Lingjun; Fung, John; Lin, Feng

    2016-09-01

    Mesenchymal stem cells (MSCs) are undergoing intensive testing in clinical trials as a promising new therapy for many inflammatory diseases and for regenerative medicine, but further optimization of current MSC-based therapies is required. In this study, we found that in addition to direct complement-mediated attack through the assembly of membrane attack complexes (MACs) that we and others have recently reported, of the released complement activation products, C5a, but not C3a, activates neutrophils in the blood to further damage MSCs through oxidative burst. In addition, we have developed a simple method for painting factor H, a native complement inhibitor, onto MSCs to locally inhibit complement activation on MSCs. MSCs painted with factor H are protected from both MAC- and neutrophil-mediated attack and are significantly more effective in inhibiting antigen-specific T cell responses than the mock-painted MSCs both in vitro and in vivo. PMID:27343468

  13. Genetics Home Reference: complement component 2 deficiency

    MedlinePlus

    ... Page Jönsson G, Sjöholm AG, Truedsson L, Bengtsson AA, Braconier JH, Sturfelt G. Rheumatological manifestations, organ damage ... 31. Review. Citation on PubMed Truedsson L, Bengtsson AA, Sturfelt G. Complement deficiencies and systemic lupus erythematosus. ...

  14. How Preschool Children Understand Missing Complement Subjects.

    ERIC Educational Resources Information Center

    Maratsos, Michael P.

    Two studies investigated preschool children's comprehension of the missing subject of infinitival complement clauses. In the first study, use of a Surface Structure Minimal Distance principle of the type outlined by C. Chomsky was distinguished from use of a Semantic Role Principle. Preschoolers acted out sentences in which the use of the two…

  15. Pneumococcal psoas pyomyositis associated with complement deficiency.

    PubMed

    Tuerlinckx, David; Bodart, Eddy; de Bilderling, Georges; Nisolle, Jean-François

    2004-04-01

    A 4.5-year-old boy with complement deficiency developed infection of the psoas caused by Streptococcus pneumoniae. Pyomyositis of the psoas muscle is uncommon but should be included in the differential diagnosis of fever and lameness. The most useful diagnostic test is computed tomography guided needle aspiration, and underlying conditions should be sought. PMID:15071302

  16. 21 CFR 866.4100 - Complement reagent.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Complement reagent. 866.4100 Section 866.4100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunology Laboratory Equipment and Reagents §...

  17. 21 CFR 866.4100 - Complement reagent.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Complement reagent. 866.4100 Section 866.4100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunology Laboratory Equipment and Reagents §...

  18. 21 CFR 866.4100 - Complement reagent.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Complement reagent. 866.4100 Section 866.4100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunology Laboratory Equipment and Reagents §...

  19. 21 CFR 866.4100 - Complement reagent.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Complement reagent. 866.4100 Section 866.4100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunology Laboratory Equipment and Reagents §...

  20. 21 CFR 866.4100 - Complement reagent.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Complement reagent. 866.4100 Section 866.4100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunology Laboratory Equipment and Reagents §...

  1. Suspected acute hemolytic transfusion reaction mediated by anti-Di(a).

    PubMed

    Bennett, Ashwini; Boyapati, Ray K; Hong, Frank S

    2015-01-01

    Anti-Di(a) can mediate hemolytic disease of the fetus and newborn, but it is unclear if it can cause hemolytic transfusion reactions (HTRs). To date, there has only been one report of a possible immediate HTR attributed to anti-Di(a). Our case report details an immediate HTR due to anti-Di(a) in a patient with pre-existing liver failure. This reaction triggered multi-organ failure, and the patient subsequently died. This case also highlights the importance of considering HTRs even when routine antibody screening has been unremarkable, particularly when electronic crossmatch is used, because of the potential for an alloantibody against a low-prevalence antigen. PMID:27187197

  2. Autoimmune hemolytic anemia induced by anti-PD-1 therapy in metastatic melanoma.

    PubMed

    Kong, Benjamin Y; Micklethwaite, Kenneth P; Swaminathan, Sanjay; Kefford, Richard F; Carlino, Matteo S

    2016-04-01

    We report the occurrence of autoimmune hemolytic anemia in a patient receiving the anti-PD-1 monoclonal antibody, nivolumab, for metastatic melanoma in the presence of known red cell alloantibodies, despite having received prior ipilimumab without evidence of hemolysis. The patient had a history of multiple red cell alloantibodies and a positive direct antiglobulin test, identified at the time of a prior transfusion, which occurred before treatment with ipilimumab. The patient developed symptomatic warm autoimmune hemolytic anemia after four cycles of treatment with nivolumab. Clinical improvement was noted following cessation of the drug and treatment with corticosteroids. Given that there was no prior history of hemolysis, even during treatment with ipilimumab, we hypothesize that anti-PD-1 therapy disrupted peripheral tolerance, unmasking an underlying autoimmune predisposition. PMID:26795275

  3. A rare case of concurrent signet-ring carcinoma of breast and microangiopathic hemolytic anemia.

    PubMed

    Lara, Kelly; Bae, Esther; Park, Hanna; Hussain, Farabi

    2016-01-01

    Microangiopathic hemolytic anemia (MAHA) can be an uncommon presentation of an underlying malignancy, most often due to signet-ring cell carcinoma (SRCC). Additionally, pure SRCC in a breast primary-tumor comprises <2% of all breast cancers (Shin SY, Park H, Chae SW, Woo HY. Microangiopathic hemolytic anemia as the first manifestation of metastatic signet-ring cell carcinoma of unknown origin: a case report and review of literature. Kor J Lab Med 2011;31:157-61). To the best of our knowledge, the combination of these two entities, pure breast primary SRCC along with MAHA, has not been reported. Here, we present such a rare case. We also evaluate the current literature regarding this and similar disease processes, of which evidence is scarce and further research is needed. PMID:27587305

  4. A thermolabile aldolase A mutant causes fever-induced recurrent rhabdomyolysis without hemolytic anemia.

    PubMed

    Mamoune, Asmaa; Bahuau, Michel; Hamel, Yamina; Serre, Valérie; Pelosi, Michele; Habarou, Florence; Nguyen Morel, Marie-Ange; Boisson, Bertrand; Vergnaud, Sabrina; Viou, Mai Thao; Nonnenmacher, Luc; Piraud, Monique; Nusbaum, Patrick; Vamecq, Joseph; Romero, Norma; Ottolenghi, Chris; Casanova, Jean-Laurent; de Lonlay, Pascale

    2014-11-01

    Aldolase A deficiency has been reported as a rare cause of hemolytic anemia occasionally associated with myopathy. We identified a deleterious homozygous mutation in the ALDOA gene in 3 siblings with episodic rhabdomyolysis without hemolytic anemia. Myoglobinuria was always triggered by febrile illnesses. We show that the underlying mechanism involves an exacerbation of aldolase A deficiency at high temperatures that affected myoblasts but not erythrocytes. The aldolase A deficiency was rescued by arginine supplementation in vitro but not by glycerol, betaine or benzylhydantoin, three other known chaperones, suggesting that arginine-mediated rescue operated by a mechanism other than protein chaperoning. Lipid droplets accumulated in patient myoblasts relative to control and this was increased by cytokines, and reduced by dexamethasone. Our results expand the clinical spectrum of aldolase A deficiency to isolated temperature-dependent rhabdomyolysis, and suggest that thermolability may be tissue specific. We also propose a treatment for this severe disease. PMID:25392908

  5. A Thermolabile Aldolase A Mutant Causes Fever-Induced Recurrent Rhabdomyolysis without Hemolytic Anemia

    PubMed Central

    Mamoune, Asmaa; Bahuau, Michel; Hamel, Yamina; Serre, Valérie; Pelosi, Michele; Habarou, Florence; Nguyen Morel, Marie-Ange; Boisson, Bertrand; Vergnaud, Sabrina; Viou, Mai Thao; Nonnenmacher, Luc; Piraud, Monique; Nusbaum, Patrick; Vamecq, Joseph; Romero, Norma; Ottolenghi, Chris; Casanova, Jean-Laurent; de Lonlay, Pascale

    2014-01-01

    Aldolase A deficiency has been reported as a rare cause of hemolytic anemia occasionally associated with myopathy. We identified a deleterious homozygous mutation in the ALDOA gene in 3 siblings with episodic rhabdomyolysis without hemolytic anemia. Myoglobinuria was always triggered by febrile illnesses. We show that the underlying mechanism involves an exacerbation of aldolase A deficiency at high temperatures that affected myoblasts but not erythrocytes. The aldolase A deficiency was rescued by arginine supplementation in vitro but not by glycerol, betaine or benzylhydantoin, three other known chaperones, suggesting that arginine-mediated rescue operated by a mechanism other than protein chaperoning. Lipid droplets accumulated in patient myoblasts relative to control and this was increased by cytokines, and reduced by dexamethasone. Our results expand the clinical spectrum of aldolase A deficiency to isolated temperature-dependent rhabdomyolysis, and suggest that thermolability may be tissue specific. We also propose a treatment for this severe disease. PMID:25392908

  6. Hemolytic Disease of the Fetus and Newborn due to Intravenous Drug Use

    PubMed Central

    Markham, Kara B.; Scrape, Scott R.; Prasad, Mona; Rossi, Karen Q.; O'Shaughnessy, Richard W.

    2016-01-01

    Objectives The objective is to present a pregnancy complication associated with intravenous drug use, namely, that of red blood cell alloimmunization and hemolytic disease of the fetus and newborn. Methods An observational case series is presented including women with red blood cell alloimmunization most likely secondary to intravenous drug abuse Results Five pregnancies were identified that were complicated by red blood cell alloimmunization and significant hemolytic disease of the fetus and newborn, necessitating intrauterine transfusion, an indicated preterm birth, or neonatal therapy. Conclusions As opioid abuse continues to increase in the United States, clinicians should be aware of the potential for alloimmunization to red blood cell antibodies as yet another negative outcome from intravenous drug abuse. PMID:26989567

  7. A rare case of concurrent signet-ring carcinoma of breast and microangiopathic hemolytic anemia†

    PubMed Central

    Lara, Kelly; Bae, Esther; Park, Hanna; Hussain, Farabi

    2016-01-01

    Microangiopathic hemolytic anemia (MAHA) can be an uncommon presentation of an underlying malignancy, most often due to signet-ring cell carcinoma (SRCC). Additionally, pure SRCC in a breast primary-tumor comprises <2% of all breast cancers (Shin SY, Park H, Chae SW, Woo HY. Microangiopathic hemolytic anemia as the first manifestation of metastatic signet-ring cell carcinoma of unknown origin: a case report and review of literature. Kor J Lab Med 2011;31:157–61). To the best of our knowledge, the combination of these two entities, pure breast primary SRCC along with MAHA, has not been reported. Here, we present such a rare case. We also evaluate the current literature regarding this and similar disease processes, of which evidence is scarce and further research is needed. PMID:27587305

  8. Complement Constructions in English: Fairly Difficult for EFL Language Learners

    ERIC Educational Resources Information Center

    Fazeli, Fatemeh; Shokrpour, Nasrin

    2012-01-01

    Complement constructions vary significantly in English and Persian. There are more complementation structures in English than in Persian and a complement structure in Persian might have more than one equivalent in English. Producing complement structures (CSs) in English is very difficult for native speakers of Persian, especially in an EFL…

  9. An In vivo Drug Screening Model Using Glucose-6-Phosphate Dehydrogenase Deficient Mice to Predict the Hemolytic Toxicity of 8-Aminoquinolines

    PubMed Central

    Zhang, Peng; Gao, Xiugong; Ishida, Hiroshi; Amnuaysirikul, Jack; Weina, Peter J.; Grogl, Max; O'Neil, Michael T.; Li, Qigui; Caridha, Diana; Ohrt, Colin; Hickman, Mark; Magill, Alan J.; Ray, Prabhati

    2013-01-01

    Anti-malarial 8-aminoquinolines drugs cause acute hemolytic anemia in individuals with glucose-6-phosphate dehydrogenase deficiency (G6PDD). Efforts to develop non-hemolytic 8-aminoquinolines have been severely limited caused by the lack of a predictive in vivo animal model of hemolytic potential that would allow screening of candidate compounds. This report describes a G6PDD mouse model with a phenotype closely resembling the G6PDD phenotype found in the African A-type G6PDD human. These G6PDD mice, given different doses of primaquine, which used as a reference hemolytic drug, display a full array of hemolytic anemia parameters, consistently and reproducibly. The hemolytic and therapeutic indexes were generated for evaluation of hemotoxicity of drugs. This model demonstrated a complete hemolytic toxicity response to another known hemolytic antimalarial drug, pamaquine, but no response to non-hemolytic drugs, chloroquine and mefloquine. These results suggest that this model is suitable for evaluation of selected 8-AQ type candidate antimalarial drugs for their hemolytic potential. PMID:23530079

  10. Complement-Opsonized HIV-1 Overcomes Restriction in Dendritic Cells

    PubMed Central

    Posch, Wilfried; Steger, Marion; Knackmuss, Ulla; Blatzer, Michael; Baldauf, Hanna-Mari; Doppler, Wolfgang; White, Tommy E.; Hörtnagl, Paul; Diaz-Griffero, Felipe; Lass-Flörl, Cornelia; Hackl, Hubert; Moris, Arnaud; Keppler, Oliver T.; Wilflingseder, Doris

    2015-01-01

    DCs express intrinsic cellular defense mechanisms to specifically inhibit HIV-1 replication. Thus, DCs are productively infected only at very low levels with HIV-1, and this non-permissiveness of DCs is suggested to go along with viral evasion. We now illustrate that complement-opsonized HIV-1 (HIV-C) efficiently bypasses SAMHD1 restriction and productively infects DCs including BDCA-1 DCs. Efficient DC infection by HIV-C was also observed using single-cycle HIV-C, and correlated with a remarkable elevated SAMHD1 T592 phosphorylation but not SAMHD1 degradation. If SAMHD1 phosphorylation was blocked using a CDK2-inhibitor HIV-C-induced DC infection was also significantly abrogated. Additionally, we found a higher maturation and co-stimulatory potential, aberrant type I interferon expression and signaling as well as a stronger induction of cellular immune responses in HIV-C-treated DCs. Collectively, our data highlight a novel protective mechanism mediated by complement opsonization of HIV to effectively promote DC immune functions, which might be in the future exploited to tackle HIV infection. PMID:26121641

  11. Complement-Opsonized HIV-1 Overcomes Restriction in Dendritic Cells.

    PubMed

    Posch, Wilfried; Steger, Marion; Knackmuss, Ulla; Blatzer, Michael; Baldauf, Hanna-Mari; Doppler, Wolfgang; White, Tommy E; Hörtnagl, Paul; Diaz-Griffero, Felipe; Lass-Flörl, Cornelia; Hackl, Hubert; Moris, Arnaud; Keppler, Oliver T; Wilflingseder, Doris

    2015-06-01

    DCs express intrinsic cellular defense mechanisms to specifically inhibit HIV-1 replication. Thus, DCs are productively infected only at very low levels with HIV-1, and this non-permissiveness of DCs is suggested to go along with viral evasion. We now illustrate that complement-opsonized HIV-1 (HIV-C) efficiently bypasses SAMHD1 restriction and productively infects DCs including BDCA-1 DCs. Efficient DC infection by HIV-C was also observed using single-cycle HIV-C, and correlated with a remarkable elevated SAMHD1 T592 phosphorylation but not SAMHD1 degradation. If SAMHD1 phosphorylation was blocked using a CDK2-inhibitor HIV-C-induced DC infection was also significantly abrogated. Additionally, we found a higher maturation and co-stimulatory potential, aberrant type I interferon expression and signaling as well as a stronger induction of cellular immune responses in HIV-C-treated DCs. Collectively, our data highlight a novel protective mechanism mediated by complement opsonization of HIV to effectively promote DC immune functions, which might be in the future exploited to tackle HIV infection. PMID:26121641

  12. Pernicious Anemia with Autoimmune Hemolytic Anemia: A Case Report and Literature Review.

    PubMed

    Yeruva, Sri Lakshmi Hyndavi; Manchandani, Raj Pal; Oneal, Patricia

    2016-01-01

    Pernicious anemia is a common cause of vitamin B12 deficiency. Here, we discuss a case of a young woman who presented with severe anemia along with a history of iron deficiency anemia. After a review of her clinical presentation and laboratory data, we identified an autoimmune hemolytic anemia and a concomitant pernicious anemia. The concurrence of both these hematological diagnoses in a patient is rare. PMID:27559485

  13. Hemolytic and cytotoxic properties of saponin purified from Holothuria leucospilota sea cucumber

    PubMed Central

    Soltani, Mozhgan; Parivar, Kazem; Baharara, Javad; Kerachian, Mohammad Amin; Asili, Javad

    2014-01-01

    Background: Holothuroids (sea cucumbers) are members of the phylum echinodermata, which produce saponins. Saponins exhibit a wide spectrum of pharmacological and biological activities. In this study, we isolated the crude saponins from the body wall of the dominant Iranian species of sea cucumber, Holothuria leucospilota (H. leucospilota). The purpose of this study was to confirm the presence of saponins in the Persian Gulf H. leucospilota and study the hemolytic and cytotoxic activities of these compounds. Methods: The body wall of sea cucumber was dried and powdered and the crude saponins were isolated using various solvents. The crude saponins were further purified by column chromatography using HP-20 resin. The foam test, Thin Layer Chromatography (TLC), hemolytic assay, and Fourier Transform Infrared Spectroscopy (FTIR) confirmed the presence of saponins. Cytotoxicity was analyzed using a 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay on A549 cells, a human lung cancer cell line. Results: The foam test, hemolytic assay, and TLC supported the presence of saponin compounds in the 80% ethanol fraction of H. leucospilota. The infrared (IR) spectrum of the extract showed hydroxyl (-OH), alkyl (C-H), ether (C-O) and ester (–C=O) absorption characteristic of teriterpenoid saponins. The C-O-C absorption indicated glycoside linkages to the sapogenins. The crude saponin extracted from sea cucumber was cytotoxic to A549 cells. Conclusion: The 80% ethanol fraction of saponin isolated from H. leucospilota exhibited hemolytic activity and offers promise as an anti-cancer candidate. PMID:26989736

  14. Relationship of bacteriocin-like inhibitor production to the pigmentation and hemolytic activity of mutans streptococci.

    PubMed

    Crooks, M; James, S M; Tagg, J R

    1987-03-01

    An inhibitor production typing (P-typing) scheme originally devised for hemolytic streptococci of Lancefield groups A-G has been successfully applied to 35 mutans streptococcus isolates recovered from plaque cultures of 60 Dunedin schoolchildren. Thirteen different P-type designations were identified. Although 11 (31%) of the isolates failed to produce detectable inhibitory activity on the conventional blood agar medium used for P-typing, four of these isolates were inhibitor-positive on Trypticase Soy agar supplemented with 2% yeast extract and 0.5% calcium carbonate (TSYCa). Four mutans strains displayed strong beta-hemolysis on Columbia agar base containing human blood when incubated in a 5% CO2 in air atmosphere. Three of these also produced weak beta-hemolysis on sheep blood-supplemented medium and were further distinctive in that they were the only inhibitor P-type 767 strains to be detected in the present study. Five mutans isolates were pigment producers and this property seemed to occur independently of both the beta-hemolytic activity and the P-type designation. Upon testing an additional collection of 18 mutans strains of various serotypes, only seven (39%) were inhibitor-positive. However, three of the four serotype c strains were inhibitor producers. Two strains of serotype d and one of serotype g were more hemolytic on sheep than on human blood agar medium. In general, it seems that the most common human mutans streptococci (serotype c strains) are more likely than are other mutans strains to produce bacteriocin-like inhibitory activity and to be hemolytic for human rather than sheep erythrocytes. PMID:3604497

  15. Complete Genome Assembly of Streptococcus pyogenes ATCC 19615, a Group A β-Hemolytic Reference Strain.

    PubMed

    Minogue, T D; Daligault, H A; Davenport, K W; Bishop-Lilly, K A; Broomall, S M; Bruce, D C; Chain, P S; Chertkov, O; Coyne, S R; Freitas, T; Frey, K G; Gibbons, H S; Jaissle, J; Redden, C L; Rosenzweig, C N; Xu, Y; Johnson, S L

    2014-01-01

    We present the complete genome assembly of Streptococcus pyogenes ATCC 19615 (Rosenbach) as submitted to GenBank under accession number CP008926. This group A nonmotile β-hemolytic clinical isolate is used for quality control in a variety of commercially available tests. The assembled genome is 1.84 Mb (38.5% G+C content) and contains 1,788 coding regions. PMID:25258274

  16. Complete Genome Assembly of Streptococcus pyogenes ATCC 19615, a Group A β-Hemolytic Reference Strain

    PubMed Central

    Minogue, T. D.; Daligault, H. A.; Davenport, K. W.; Bishop-Lilly, K. A.; Broomall, S. M.; Bruce, D. C.; Chain, P. S.; Chertkov, O.; Coyne, S. R.; Freitas, T.; Frey, K. G.; Gibbons, H. S.; Jaissle, J.; Redden, C. L.; Rosenzweig, C. N.; Xu, Y.

    2014-01-01

    We present the complete genome assembly of Streptococcus pyogenes ATCC 19615 (Rosenbach) as submitted to GenBank under accession number CP008926. This group A nonmotile β-hemolytic clinical isolate is used for quality control in a variety of commercially available tests. The assembled genome is 1.84 Mb (38.5% G+C content) and contains 1,788 coding regions. PMID:25258274

  17. Could β-hemolytic, group B Enterococcus faecalis be mistaken for Streptococcus agalactiae?

    PubMed

    Savini, Vincenzo; Gherardi, Giovanni; Marrollo, Roberta; Franco, Alessia; Pimentel De Araujo, Fernanda; Dottarelli, Samuele; Fazii, Paolo; Battisti, Antonio; Carretto, Edoardo

    2015-05-01

    A β-hemolytic Enterococcus faecalis strain agglutinating Lancefield group A, B, C, D, F, and G antisera was observed from a rectovaginal swab, in the context of antenatal screening for Streptococcus agalactiae (group B Streptococcus [GBS]). This is the first multi-Lancefield antisera-agglutinating isolate of this species, and it raised particular concern, as it may mimic GBS, leading to false reporting and useless receipt of intrapartum antibiotics. PMID:25766004

  18. Antioxidant, hemolytic and cytotoxic activities of Senecio species used in traditional medicine of northwestern Argentina.

    PubMed

    Lizarraga, Emilio; Castro, Felipe; Fernández, Francisco; de Lampasona, Marina P; Catalán, César A N

    2012-05-01

    Senecio nutans Sch. Bip., S. viridis var. viridis Phill. and S. spegazzinii Cabrera are native species used in traditional medicine of northwestern Argentina. The total phenolics, flavonoids and caffeoylquinic acids contents, as well as radical scavenging, antioxidant, hemolytic and cytotoxic activities of aqueous extracts (infusion and decoction) of all three species were determined. S. nutans was the most active. The extracts did not show antibacterial activity. Alkaloids were not detected in any of the aqueous extracts of the three studied species. PMID:22799087

  19. Pernicious Anemia with Autoimmune Hemolytic Anemia: A Case Report and Literature Review

    PubMed Central

    Manchandani, Raj Pal; Oneal, Patricia

    2016-01-01

    Pernicious anemia is a common cause of vitamin B12 deficiency. Here, we discuss a case of a young woman who presented with severe anemia along with a history of iron deficiency anemia. After a review of her clinical presentation and laboratory data, we identified an autoimmune hemolytic anemia and a concomitant pernicious anemia. The concurrence of both these hematological diagnoses in a patient is rare. PMID:27559485

  20. Complement Factor C4d Is a Common Denominator in Thrombotic Microangiopathy.

    PubMed

    Chua, Jamie S; Baelde, Hans J; Zandbergen, Malu; Wilhelmus, Suzanne; van Es, Leendert A; de Fijter, Johan W; Bruijn, Jan A; Bajema, Ingeborg M; Cohen, Danielle

    2015-09-01

    Complement activation has a major role in thrombotic microangiopathy (TMA), a disorder that can occur in a variety of clinical conditions. Promising results of recent trials with terminal complement-inhibiting drugs call for biomarkers identifying patients who might benefit from this treatment. The primary aim of this study was to determine the prevalence and localization of complement factor C4d in kidneys of patients with TMA. The secondary aims were to determine which complement pathways lead to C4d deposition and to determine whether complement activation results in deposition of the terminal complement complex. We examined 42 renal sections with histologically confirmed TMA obtained from a heterogeneous patient group. Deposits of C4d, mannose-binding lectin, C1q, IgM, and C5b-9 were scored in the glomeruli, peritubular capillaries, and arterioles. Notably, C4d deposits were present in 88.1% of TMA cases, and the various clinical conditions had distinct staining patterns within the various compartments of the renal vasculature. Classical pathway activation was observed in 90.5% of TMA cases. C5b-9 deposits were present in 78.6% of TMA cases and in 39.6% of controls (n=53), but the staining pattern differed between cases and controls. In conclusion, C4d is a common finding in TMA, regardless of the underlying clinical condition. Moreover, C5b-9 was present in >75% of the TMA samples, suggesting that terminal complement inhibitors may have a beneficial effect in these patients. C4d and C5b-9 should be investigated as possible diagnostic biomarkers in the clinical work-up of patients suspected of having complement-mediated TMA. PMID:25573909

  1. [Infantile pyknocytosis: A cause of noenatal hemolytic anemia. Is recombinant erythropoietin an alternative to transfusion?].

    PubMed

    Bagou, M; Rolland, E; Gay, C; Patural, H

    2016-01-01

    Infantile pyknocytosis is a neonatal hemolytic disorder which causes anemia and icterus and is characterized by the presence of an increased number of distorted red blood cells called pyknocytes. Resolution spontaneously occurs in the first semester of life. It has been generally described as a rare entity, with an occasional family history. We report seven cases of infantile pyknocytosis observed in our hospital in 3 years. Most of the infants presented with hemolytic icterus and profound anemia that was reaching its peak by the 3rd week of life. Three neonates received one to three red blood cell transfusions, according to former recommendations. However, the following four received a treatment with recombinant erythropoietin administered subcutaneously. Only one of these four cases required a transfusion. All of them were free of hematological disease 2-3 months after completion of treatment. Infantile pyknocytosis is a recognized cause of neonatal hemolytic anemia, which requires careful examination of red cell morphology on a peripheral blood smear. The cause of this transient disorder remains unknown. Our observations show that recombinant erythropoietin therapy is effective in treating infantile pyknocytosis and increases the reticulocyte response, thus improving the hemoglobin level. PMID:26563723

  2. Effects of extremely low frequency magnetic field on production of mannatide by α-hemolytic Streptococcus.

    PubMed

    Zhang, Jialan; Xu, Cui; Wan, Yunlei; Gao, Mengxiang

    2016-07-01

    The effect of the extremely low frequency magnetic field (ELF-MF) on biomass and mannatide production by α-hemolytic Streptococcus in liquid-state fermentation culture medium was studied during shake flask culture. Magnetic field (MF) inductions, exposure times, and exposure periods varied in a range of 0-1.5 mT, 0-16 h, and six periods of incubation time, respectively. Results showed both biomass and mannatide production increased significantly at MF induction 0.4, 0.6, and 0.9 mT and decreased at both 1.2 and 1.5 mT. Biomass increased by exposure for initial and middle stages of fermentation. Mannatide production increased significantly at 4-8, 8-12, and 17-21 h. Peak yield of biomass and mannatide production increased by 10.7% and 14.0% at 25 and 27 h of incubation at 0.6 mT MF induction and exposure to 8-12 h of incubation time, compared with the control experiment, respectively. ELF-MF could also enhance the growth rate and mannatide production rate of α-hemolytic Streptococcus. However, ELF-MF did not alter α-hemolytic Streptococcus cell growth and mannatide metabolizing regulation or fermentation pattern. Mannatide production was not associated with cellular growth but rather only partially associated. Bioelectromagnetics. 37:331-337, 2016. © 2016 Wiley Periodicals, Inc. PMID:27271865

  3. Clinicopathologic features of young and old sphha/sphha mice. Mutants with congenital hemolytic anemia.

    PubMed Central

    Maggio-Price, L.; Russell, R.; Wolf, N. S.; Alpers, C. E.; Engel, D.

    1988-01-01

    A colony of mice with congenital hemolytic anemia, sphha/sphha, were evaluated over a 3-year period. Prominent findings included decreased survivability, reticulocytosis, increased peripheral blood leukocytes, extramedullary hematopoiesis in liver and spleen, lymphoid hyperplasia and membranoproliferative glomerulonephritis. Older (12 to 21 months) anemic animals had elevated serum levels of IgG1 and IgA. There was deposition of C3, IgG, IgM, and IgA in renal glomeruli of both control and anemic mice, but deposition of IgM and IgA was more prominent and widely distributed in anemic animals and correlated with mesangial expansion and the presence of electron dense deposits in the mesangium and in glomerular capillary walls. Prominent renal tubular hemosiderosis was noted in young and old anemic mice. The relation between the hemolytic anemia and glomerular disease is unclear but these mice may be an animal model useful for exploration of changes attendant with chronic hemolysis and evaluation of renal disease that accompanies hemolytic anemia. Images Figure 1 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 PMID:3414779

  4. Mast cell degranulation by a hemolytic lipid toxin decreases GBS colonization and infection

    PubMed Central

    Gendrin, Claire; Vornhagen, Jay; Ngo, Lisa; Whidbey, Christopher; Boldenow, Erica; Santana-Ufret, Veronica; Clauson, Morgan; Burnside, Kellie; Galloway, Dionne P.; Waldorf, Kristina Adams; Piliponsky, Adrian M.; Rajagopal, Lakshmi

    2015-01-01

    Ascending infection of microbes from the lower genital tract into the amniotic cavity increases the risk of preterm birth, stillbirth, and newborn infections. Host defenses that are critical for preventing ascending microbial infection are not completely understood. Group B Streptococcus (GBS) are Gram-positive bacteria that frequently colonize the lower genital tract of healthy women but cause severe infections during pregnancy, leading to preterm birth, stillbirth, or early-onset newborn infections. We recently described that the GBS pigment is hemolytic, and increased pigment expression promotes GBS penetration of human placenta. Here, we show that the GBS hemolytic pigment/lipid toxin and hyperpigmented GBS strains induce mast cell degranulation, leading to the release of preformed and proinflammatory mediators. Mast cell–deficient mice exhibit enhanced bacterial burden, decreased neutrophil mobilization, and decreased immune responses during systemic GBS infection. In a vaginal colonization model, hyperpigmented GBS strains showed increased persistence in mast cell–deficient mice compared to mast cell–proficient mice. Consistent with these observations, fewer rectovaginal GBS isolates from women in their third trimester of pregnancy were hyperpigmented/hyperhemolytic. Our work represents the first example of a bacterial hemolytic lipid that induces mast cell degranulation and emphasizes the role of mast cells in limiting genital colonization by hyperpigmented GBS. PMID:26425734

  5. [Resistance to antimicrobial agents, hemolytic activity and plasmids in Aeromonas species].

    PubMed

    Morita, K; Watanabe, N; Kanamori, M

    1990-06-01

    A total of 174 Aeromonas isolates consisting of 100 strains from patients with diarrhea being mainly overseas travellers nd healthy subjects, and 74 strains from environmental sources including foods, fish, fresh water, sea water and river soil collected in the area of Tokyo Metropolis and Kanagawa Prefecture was examined for the antimicrobial resistance, presence of plasmids and hemolytic activity. Almost all the isolates (99.4%) were resistant to aminobenzyl penicillin. The isolation frequency of chloramphenicol- or tetracycline-resistant strain was low. Most environmental isolates of A. hydrophila were resistant to multiple antimicrobial agents. Thirty-seven percent of environmental isolates and 39% of human fecal ones carried plasmids. In environmental isolates, seven A. hydrophila and three A. sobria strains carried 63- to 150-kilobase pair (kb) conjugative R plasmids. Two A. hydrophila strains from both the healthy subject and domestic case with diarrhea carried 58- to 90-kb conjugative R plasmids, respectively. None of the isolates from the feces of overseas traveller's diarrhea carried the plasmid. Irrespective of the sources. A. hydrophila showed the highest hemolytic activity among three Aeromonas species. Eighty percent or more of A. hydrophila isolates were of hemolysin positive. The hemolytic titer of A. hydrophila strains from human feces was higher than that of the strains from environmental sources. PMID:2401817

  6. Metformin-Induced Hemolytic Anemia in a Patient With Glucose-6-Phosphate Dehydrogenase Deficiency.

    PubMed

    Ruggiero, Nicole A; Kish, Troy D; Lee, Mikyung L

    2016-01-01

    Metformin, an oral antidiabetic agent, is considered the preferred first-line therapy for patients with type II diabetes. Between 2010 and 2012, it has been estimated that 14 million Americans were administered an oral antidiabetic agent, suggesting the extensive use of metformin among the diabetic population. There have been few case reports implicating metformin in causing hemolytic anemia. We present a case of a 53-year-old white male who developed hemolytic anemia after the initiation of treatment with metformin 500 mg twice daily. The patient experienced a 1.5 g/dL decrease in hemoglobin from baseline and a 2.8 mg/dL increase in total bilirubin within 1 day of treatment. Laboratory results confirmed that the patient was also glucose-6-phosphate dehydrogenase deficient. The hemolytic anemia resolved on discontinuation of metformin. Although this adverse effect seems to be rare, it is important to consider its seriousness. Clinicians should be advised to closely monitor patients newly started on metformin. PMID:25756470

  7. An Inhibitor of the Alternative Pathway of Complement in Saliva of New World Anopheline Mosquitoes.

    PubMed

    Mendes-Sousa, Antonio F; Queiroz, Daniel C; Vale, Vladimir F; Ribeiro, José M C; Valenzuela, Jesus G; Gontijo, Nelder F; Andersen, John F

    2016-07-15

    The complement system present in circulating blood is an effective mechanism of host defense, responsible for the killing of pathogens and the production of potent anaphylatoxins. Inhibitors of the complement system have been described in the saliva of hematophagous arthropods that are involved in the protection of digestive tissues against complement system-mediated damage. In this study, we describe albicin, a novel inhibitor of the alternative pathway of complement from the salivary glands of the malaria vector, Anopheles albimanus The inhibitor was purified from salivary gland homogenates by reverse-phase HPLC and identified by mass spectrometry as a small (13.4-kDa) protein related to the gSG7 protein of Anopheles gambiae and Anopheles stephensi Recombinant albicin was produced in Escherichia coli and found to potently inhibit lysis of rabbit erythrocytes in assays of the alternative pathway while having no inhibitory effect on the classical or lectin pathways. Albicin also inhibited the deposition of complement components on agarose-coated plates, although it could not remove previously bound components. Antisera produced against recombinant albicin recognized both the native and recombinant inhibitors and also blocked their activities in in vitro assays. Using surface plasmon resonance and enzymatic assays, we found that albicin binds and stabilizes the C3-convertase complex (C3bBb) formed on a properdin surface and inhibits the convertase activity of a reconstituted C3bBb complex in solution. The data indicate that albicin specifically recognizes the activated form of the complex, allowing more efficient inhibition by an inhibitor whose quantity is limited. PMID:27307559

  8. Herpes simplex virus glycoprotein C: molecular mimicry of complement regulatory proteins by a viral protein.

    PubMed

    Huemer, H P; Wang, Y; Garred, P; Koistinen, V; Oppermann, S

    1993-08-01

    Herpes simplex virus (HSV) encodes a protein, glycoprotein C (gC), which binds to the third complement component, the central mediator of complement activation. In this study the structural and functional relationships of gC from HSV type 1 (HSV-1) and known human complement regulatory proteins factor H, properdin, factor B, complement receptor 1 (CR1) and 2 (CR2) were investigated. The interaction of gC with C3b was studied using purified complement components, synthetic peptides, antisera against different C3 fragments and anti-C3 monoclonal antibodies (mAb) with known inhibitory effects on C3-ligand interactions. All the mAb that inhibited gC/C3b interactions, in a differential manner, also prevented binding of C3 fragments to factors H, B, CR1 or CR2. No blocking was observed with synthetic peptides representing different C3 regions or with factor B and C3d, whereas C3b, C3c and factor H were inhibitory, as well as purified gC. There was no binding of gC to cobra venom factor (CVF), a C3c-like fragment derived from cobra gland. Purified gC bound to iC3, iC3b and C3c, but failed to bind to C3d. Glycoprotein C bound only weakly to iC3 derived from bovine and porcine plasma, thus indicating a preference of the viral protein for the appropriate host. Binding of gC was also observed to proteolytic C3 fragments, especially to the beta-chain, thus suggesting the importance of the C3 region as a binding site. Purified gC from HSV-1, but not HSV-2, inhibited the binding of factor H and properdin but not of CR1 to C3b. The binding of iC3b to CR2, a molecule involved in B-cell activation and binding of the Epstein-Barr virus, was also inhibited by the HSV-1 protein. As factor H and properdin, the binding of which was inhibited by gC, are important regulators of the alternative complement pathway, these data further support a role of gC in the evasion of HSV from a major first-line host defence mechanism, i.e. the complement system. In addition, the inhibition of the C3/CR

  9. Chronic Low Level Complement Activation within the Eye Is Controlled by Intraocular Complement Regulatory Proteins

    PubMed Central

    Sohn, Jeong-Hyeon; Kaplan, Henry J.; Suk, Hye-Jung; Bora, Puran S.; Bora, Nalini S.

    2007-01-01

    Purpose To explore the role of the complement system and complement regulatory proteins in an immune-privileged organ, the eye. Methods Eyes of normal Lewis rats were analyzed for the expression of complement regulatory proteins, membrane cofactor protein (MCP), decay-acceleration factor (DAF), membrane inhibitor of reactive lysis (MIRL, CD59), and cell surface regulator of complement (Crry), using immunohistochemistry, Western blot analysis, and reverse transcription–polymerase chain reaction (RT-PCR). Zymosan, a known activator of the alternative pathway of complement system was injected into the anterior chamber of the eye of Lewis rats. Animals were also injected intracamerally with 5 μl (25 μg) of neutralizing monoclonal antibody (mAb) against rat Crry (5I2) or CD59 (6D1) in an attempt to develop antibody induced anterior uveitis; control animals received 5 μl of sterile phosphate-buffered saline (PBS), OX-18 (25 μg), G-16-510E3 (25 μg), or MOPC-21 (25 μg). The role of complement system in antibody-induced uveitis was explored by intraperitoneal injection of 35 U cobra venom factor (CVF), 24 hours before antibody injection. Immunohistochemical staining and sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) with Western blot analysis were used to detect the presence of membrane attack complex (MAC) and C3 activation products, respectively, in normal and antibody-injected rat eyes. Results Complement activation product MAC was present in the normal rat eye, and intraocular injection of zymosan induced severe anterior uveitis. The complement regulatory proteins, MCP, DAF, CD59, and Crry, were identified in the normal rat eye. Soluble forms of Crry and CD59 were also detected in normal rat aqueous humor. Severe anterior uveitis developed in Lewis rats injected with a neutralizing mAb against Crry, with increased formation of C3 split products. Systemic complement depletion by CVF prevented the induction of anterior uveitis by anti

  10. Antibody-independent activation of the classical pathway of human seru