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Sample records for classical complement activation

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

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    Ran Sun

    2015-12-01

    Full Text Available 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.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.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.

  2. Inhibition of classical complement activation attenuates liver ischaemia and reperfusion injury in a rat model

    NARCIS (Netherlands)

    B.H.M. Heijnen; I.H. Straatsburg; N.D. Padilla; G.J. Mierlo; C.E. Hack; T.M. van Gulik

    2006-01-01

    Activation of the complement system contributes to the pathogenesis of ischaemia/reperfusion (I/R) injury. We evaluated inhibition of the classical pathway of complement using C1-inhibitor (C1-inh) in a model of 70% partial liver I/R injury in male Wistar rats (n = 35). C1-inh was administered at 10

  3. Classical Complement Pathway Activation in the Kidneys of Women With Preeclampsia.

    Science.gov (United States)

    Penning, Marlies; Chua, Jamie S; van Kooten, Cees; Zandbergen, Malu; Buurma, Aletta; Schutte, Joke; Bruijn, Jan Anthonie; Khankin, Eliyahu V; Bloemenkamp, Kitty; Karumanchi, S Ananth; Baelde, Hans

    2015-07-01

    A growing body of evidence suggests that complement dysregulation plays a role in the pathogenesis of preeclampsia. The kidney is one of the major organs affected in preeclampsia. Because the kidney is highly susceptible to complement activation, we hypothesized that preeclampsia is associated with renal complement activation. We performed a nationwide search for renal autopsy material in the Netherlands using a computerized database (PALGA). Renal tissue was obtained from 11 women with preeclampsia, 25 pregnant controls, and 14 nonpregnant controls with hypertension. The samples were immunostained for C4d, C1q, mannose-binding lectin, properdin, C3d, C5b-9, IgA, IgG, and IgM. Preeclampsia was significantly associated with renal C4d-a stable marker of complement activation-and the classical pathway marker C1q. In addition, the prevalence of IgM was significantly higher in the kidneys of the preeclamptic women. No other complement markers studied differed between the groups. Our findings in human samples were validated using a soluble fms-like tyrosine kinase 1 mouse model of preeclampsia. The kidneys in the soluble fms-like tyrosine kinase 1-injected mice had significantly more C4 deposits than the control mice. The association between preeclampsia and renal C4d, C1q, and IgM levels suggests that the classical complement pathway is involved in the renal injury in preeclampsia. Moreover, our finding that soluble fms-like tyrosine kinase 1-injected mice develop excess C4 deposits indicates that angiogenic dysregulation may play a role in complement activation within the kidney. We suggest that inhibiting complement activation may be beneficial for preventing the renal manifestations of preeclampsia. © 2015 American Heart Association, Inc.

  4. Demonstration of alternative and classical complement pathway activity in colostrum from buffalo (Bubalus bubalis).

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    Matheswaran, K; Dhinakar Raj, G; Nachimuthu, K

    2003-09-01

    Buffalo colostrum caused lysis of unsensitized red blood cells (RBC) from sheep, goats, rabbits and chickens. RBC from cattle and buffalo were resistant to lysis. That lysis was due to the presence of natural antibodies to these RBC was ruled out since there was no reduction in haemolytic titres even after adsorption with the respective RBC. The addition of EGTA to the diluent had no effect on the haemolytic activity. These findings indicate the presence of alternative complement pathway (ACP) activity in buffalo colostrum. The haemolytic activity of buffalo complement for unsensitized rabbit RBC was reduced to very low levels by heating at 50 degrees C for 45 min. Treatment with zymosan also inhibited the haemolytic activity, while inulin had no effect. The maximum activity of ACP occurred in the presence of 4 mmol/L Mg(2+) in the diluent. The range of ACP activities in colostrum from buffaloes varied from 4.06 to 8.48 CH50 units/ml. Using a standard system for titrating the classical complement pathway and rabbit red blood cells sensitized with goat haemolysin, the range of complement activity in buffalo colostrum was 4.81-6.77 CH50/ml.

  5. Inhibition of classical complement activation attenuates liver ischaemia and reperfusion injury in a rat model.

    Science.gov (United States)

    Heijnen, B H M; Straatsburg, I H; Padilla, N D; Van Mierlo, G J; Hack, C E; Van Gulik, T M

    2006-01-01

    Activation of the complement system contributes to the pathogenesis of ischaemia/reperfusion (I/R) injury. We evaluated inhibition of the classical pathway of complement using C1-inhibitor (C1-inh) in a model of 70% partial liver I/R injury in male Wistar rats (n = 35). C1-inh was administered at 100, 200 or 400 IU/kg bodyweight, 5 min before 60 min ischaemia (pre-I) or 5 min before 24 h reperfusion (end-I). One hundred IU/kg bodyweight significantly reduced the increase of plasma levels of activated C4 as compared to albumin-treated control rats and attenuated the increase of alanine aminotransferase (ALT). These effects were not better with higher doses of C1-inh. Administration of C1-inh pre-I resulted in lower ALT levels and higher bile secretion after 24 h of reperfusion than administration at end-I. Immunohistochemical assessment indicated that activated C3, the membrane attack complex C5b9 and C-reactive protein (CRP) colocalized in hepatocytes within midzonal areas, suggesting CRP is a mediator of I/R-induced, classical complement activation in rats. Pre-ischaemic administration of C1-inh is an effective pharmacological intervention to protect against liver I/R injury.

  6. Activated complement classical pathway in a murine model of oxygen-induced retinopathy

    Institute of Scientific and Technical Information of China (English)

    Xue-Ying; Tao; Shi-Jie; Zheng; Bo; Lei

    2015-01-01

    AIM: To investigate whether the complement system is involved in a murine model of oxygen-induced retinopathy(OIR).METHODS: Forty C57BL/6J newborn mice were divided randomly into OIR group and control group. OIR was induced by exposing mice to 75% ±2% oxygen from postnatal 7d(P7) to P12 and then recovered in room air.For the control group, the litters were raised in room air.At the postnatal 17d(P17), gene expressions of the complement components of the classical pathway(CP),the mannose-binding lectin(MBL) pathway and the alternative pathway(AP) in the retina were determined by quantitative real-time polymerase chain reaction(RT-PCR). Retinal protein expressions of the key components in the CP were examined by Western blotting.· RESULTS: Whole mounted retina in the OIR mice showed area of central hypoperfusion in both superficial and deep layers and neovascular tufts in the periphery.The expressions of C1 qb and C4 b genes in the OIR retina were significantly higher than those of the controls. The expression of retinal complement factor B(CFB) gene in OIR mice was significantly lower than those of the controls. However, the expressions of C3 and complement factor H(CFH) genes were higher. The protein synthesis of the key components involved in the CP(C1q, C4 and C3) were also significantly higher in OIR mouse retina. Although MBL-associated serine protease 1(MASP1) and MASP2 were detected in both the OIR and the control groups, the expressions were weak and the difference between the two groups was not significant.CONCLUSION: Our data suggest that the complement system CP is activated during the pathogenesis of murine model of OIR.

  7. Molluskan Hemocyanins Activate the Classical Pathway of the Human Complement System through Natural Antibodies

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    Pizarro-Bauerle, Javier; Maldonado, Ismael; Sosoniuk-Roche, Eduardo; Vallejos, Gerardo; López, Mercedes N.; Salazar-Onfray, Flavio; Aguilar-Guzmán, Lorena; Valck, Carolina; Ferreira, Arturo; Becker, María Inés

    2017-01-01

    Molluskan hemocyanins are enormous oxygen-carrier glycoproteins that show remarkable immunostimulatory properties when inoculated in mammals, such as the generation of high levels of antibodies, a strong cellular reaction, and generation of non-specific antitumor immune responses in some types of cancer, particularly for superficial bladder cancer. These proteins have the ability to bias the immune response toward a Th1 phenotype. However, despite all their current uses with beneficial clinical outcomes, a clear mechanism explaining these properties is not available. Taking into account reports of natural antibodies against the hemocyanin of the gastropod Megathura crenulata [keyhole limpet hemocyanin (KLH)] in humans as well as other vertebrate species, we report here for the first time, the presence, in sera from unimmunized healthy donors, of antibodies recognizing, in addition to KLH, two other hemocyanins from gastropods with documented immunomodulatory capacities: Fisurella latimarginata hemocyanin (FLH) and Concholepas concholepas hemocyanin (CCH). Through an ELISA screening, we found IgM and IgG antibodies reactive with these hemocyanins. When the capacity of these antibodies to bind deglycosylated hemocyanins was studied, no decreased interaction was detected. Moreover, in the case of FLH, deglycosylation increased antibody binding. We evaluated through an in vitro complement deposition assay whether these antibodies activated the classical pathway of the human complement system. The results showed that all three hemocyanins and their deglycosylated counterparts elicited this activation, mediated by C1 binding to immunoglobulins. Thus, this work contributes to the understanding on how the complement system could participate in the immunostimulatory properties of hemocyanins, through natural, complement-activating antibodies reacting with these proteins. Although a role for carbohydrates cannot be completely ruled out, in our experimental setting

  8. Peptide inhibitor of complement C1 (PIC1, a novel suppressor of classical pathway activation: mechanistic studies and clinical potential

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    Julia A Sharp

    2014-08-01

    Full Text Available The classical pathway of complement plays multiple physiological roles including modulating immunological effectors initiated by adaptive immune responses as well as 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 (CAD, 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 (HAE, 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 inhibit 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 fifteen amino acids. PIC1 inhibits classical pathway mediated complement activation in ABO incompatibility in vitro as well as 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.

  9. Early Components of the Complement Classical Activation Pathway in Human Systemic Autoimmune Diseases

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    Katherine eLintner

    2016-02-01

    Full Text Available The complement system consists of effector proteins, regulators, and receptors that participate in host defense against pathogens. Activation of the complement system, via the classical pathway (CP, has long been recognized in immune complex-mediated tissue injury, most notably systemic lupus erythematosus (SLE. Paradoxically, a complete deficiency of an early component of the CP, as evidenced by homozygous genetic deficiencies reported in human, are strongly associated with the risk of developing SLE or a lupus-like disease. Similarly, isotype deficiency attributable to a gene copy number variation, and/or the presence of autoantibodies directed against a CP component or a regulatory protein that result in an acquired deficiency are relatively common in SLE patients. Applying accurate assay methodologies with rigorous data validations, low gene copy numbers of total C4, heterozygous and homozygous deficiencies of C4A have been shown as medium to large effect size risk factors, while high copy numbers of total C4 or C4A as prevalent protective factors, of European and East-Asian SLE. Here, we summarize the current knowledge related to genetic deficiency and insufficiency, and acquired protein alterations for C1q, C1r, C1s, C4A/C4B, and C2 in disease pathogenesis and prognosis of SLE, and, briefly, for other systemic autoimmune diseases. As the complement system is increasingly found to be associated with autoimmune diseases, it has become an attractive therapeutic target. We highlight the recent developments and offer a balanced perspective concerning future investigations and therapeutic applications with a focus on early components of the CP in human systemic autoimmune diseases.

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

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    Brandon L Garcia

    2016-01-01

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  12. Classical complement pathway activation in the kidneys of women with preeclampsia

    NARCIS (Netherlands)

    Penning, Marlies; Chua, Jamie S.; Van Kooten, Cees; Zandbergen, Malu; Buurma, Aletta; Schutte, Joke; Bruijn, Jan Anthonie; Khankin, Eliyahu V.; Bloemenkamp, Kitty; Karumanchi, S. Ananth; Baelde, Hans

    2015-01-01

    A growing body of evidence suggests that complement dysregulation plays a role in the pathogenesis of preeclampsia. The kidney is one of the major organs affected in preeclampsia. Because the kidney is highly susceptible to complement activation, we hypothesized that preeclampsia is associated with

  13. Significance of complement components C1q and C4 bound to circulating immune complexes in juvenile idiopathic arthritis: support for classical complement pathway activation.

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    Gilliam, Brooke E; Reed, Melinda R; Chauhan, Anil K; Dehlendorf, Amanda B; Moore, Terry L

    2011-01-01

    Immune complexes (ICs) from sera of juvenile idiopathic arthritis (JIA) patients show increased complement opsonisation; however, a definitive role for involvement of the classical or alternative pathway is not entirely clear. To delineate the role of these pathways, we measured activated complement products bound to circulating IC (CICs) in the sera of JIA patients. Sera from 100 JIA patients and 22 healthy children were collected. C1q, C4, C3, C3d, and membrane attack complex (MAC) bound to CICs were measured by enzyme-linked immunosorbent assay. Data was compared to IgM rheumatoid factor (RF), IgG anti-cyclic citrullinated peptide (CCP) antibodies, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) levels. Mean levels of C1q, C4, and MAC bound to CICs were significantly elevated in JIA patients compared to healthy children. C1q correlated significantly with C4 and MAC bound to CICs and C4 and MAC also demonstrated significant correlation. No significant differences were noted in complement components bound to CICs when evaluating IgM RF, anti-CCP antibody, and CRP positivity. A significant correlation was noted between MAC bound to CICs and ESR. C1q and MAC bound to CICs mean levels were significantly higher in patients with an elevated ESR compared to those with a normal ESR level. JIA patients have elevated levels of complement components bound to CICs, particularly from the classical pathway. Moreover, classical pathway components were associated with ESR, a marker of disease activity. MAC bound to CICs also correlated significantly with ESR, further supporting the notion of complement-mediated tissue injury that is triggered by IC-mediated classical pathway activation.

  14. Activation capacity of the alternative and classic complement pathways in patients operated on for colorectal cancer

    DEFF Research Database (Denmark)

    Zimmermann-Nielsen, Erik; Iversen, Lene H; Svehag, Sven-Erik;

    2002-01-01

    . Significant differences in C3 activation capacities were observed between cancer patients that were related to Dukes stage and in patients with and without buffy coat-depleted red cells suspended in saline, adenine, glucose, and mannitol transfusion, infectious events, and deep venous thromboembolism......PURPOSE: Tumor cells may suppress activation of the host's complement system, and the functional state of the complement system may be a prognostic marker of outcome in patients with malignancies. Serial plasma samples from patients undergoing intended curative surgery for colorectal cancer were...... analyzed for complement factor C3 activation capacity. METHODS: Samples were collected from 91 patients with colorectal cancer and 13 with benign colorectal diseases before surgery and 1, 2, and 7 days after surgery, between 8 and 13 days after surgery, and 3, 6, 12, 18, 24, 36, 48, and 60 months after...

  15. Synthesis and classical pathway Complement inhibitory activity of C7-functionalized filifolinol derivatives, inspired in K-76 COOH.

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    Larghi, Enrique L; Operto, María A; Torres, Rene; Kaufman, Teodoro S

    2012-09-01

    A series of carboxylic acids carrying various functionalization on C-7 of their common 3H-spiro[benzofuran-2,1'-cyclohexane] skeleton were synthesized from filifolinol, as analogs of the natural Complement inhibitor K-76 COOH. In order to probe the relevance of the C-7 functionalization on their bioactivity, the ability of the analogs to inhibit Complement activation through the classical pathway was determined. The observed results suggest that functionalization of C-7 can modulate the inhibitory activity of the tested compounds. The 7-trifluoromethyl derivative was the compound with the lowest IC(50) value among the tested analogs (IC(50) = 100 μM), being more potent than K-76 COOH (IC(50) = 570 μM).

  16. Complement activation by isolated myelin: activation of the classical pathway in the absence of myelin-specific antibodies.

    OpenAIRE

    Vanguri, P; Koski, C L; Silverman, B.; Shin, M L

    1982-01-01

    Many pathological conditions of the central nervous system involve damage to and removal of myelin membrane. Very little is known about initiation of this membrane damage and the mechanisms of disposal of the damaged tissue. We are interested in the interaction between complement (the components of complement are designated C1, C2, C3, etc.) and myelin membranes and the possible role of complement in amplifying myelin damage and in the disposal of damaged myelin in vivo, because activation of...

  17. Correlation of systemic lupus erythematosus disease activity with classical complement (CH50 function and related protein levels

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    Salesi M

    2008-09-01

    Full Text Available "nBackground: The components of the classical complement pathway play an important role in the pathogenesis of systemic lupus erythematosus (SLE and are reportedly useful biomarkers of disease activity. In this study, we evaluate disease activity, complement function (total hemolytic complement, CH50 and complement protein levels (C3, C4, C3d, C4d, SC5b-9, comparing the results of patients with active disease versus those with inactive disease."n"nMethods: This cross-sectional study included 78 hospitalized women with SLE, 24 of whom were in the active group, with SLE disease activity indexes (SLEDAI.2K of >6, and 54 in the inactive group, with SLEDAI.2K of ≤6. Serum CH50 was measured using a red blood cell hemolytic assay. C3 and C4 levels were determined by nephlometry and plasma levels of C3d, C4d, SC5b-9 by ELISA. The data were statistically analyzed using SPSS."n"nResults: The mean (±standard error C4d levels of the inactive group were significantly higher than those of the active group (23.39±1.1µg/ml and 16.9±1.6µg/ml, respectively; p=0.003. There was also a significant correlation between C3 and C4 levels (p=0.807. The mean values of the other proteins (C3, C4, CH50, SC5b-9, and C3d circulating immune complex concentrations were not significantly different between the inactive group vs. the active group: 89.35±6.8 vs. 85.54±7.6mg/dl, 18.33±2.3 vs. 20.45±2.4mg/dl, 149.03±4.3 vs. 157±4.3U, 1414.4±114.94 vs. 1471.1±216.9ng/ml, 9.43±0.96 vs. 13.31±3.16µgEq/ml, respectively (p>0.05."n"nConclusions: According to our results, C4d levels may be used as a biomarker of disease activity. The significant correlation between C3 and C4 may confirm the activity of the classical pathway in SLE patients."n"nKeywords: Systemic lupus erythematosus, CH50, C3, C4, C3d, C4d, SC5b-9, inactive, flare.

  18. Enzymatically Modified Low-Density Lipoprotein Is Recognized by C1q and Activates the Classical Complement Pathway

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    Gérard J. Arlaud

    2011-01-01

    Full Text Available Several studies suggest that the complement system is involved in atherogenesis. To further investigate this question, we have studied the ability of native and modified forms of LDL to bind and activate C1, the complex protease that triggers the classical pathway of complement. Unlike native LDL, oxidized (oxLDL and enzymatically modified (E-LDL derivatives were both recognized by the C1q subunit of C1, but only E-LDL particles, obtained by sequential treatment with a protease and then with cholesterol esterase, had the ability to trigger C1 activation. Further investigations revealed that C1q recognizes a lipid component of E-LDL. Several approaches, including reconstitution of model lipid vesicles, cosedimentation, and electron microscopy analyses, provided evidence that C1 binding to E-LDL particles is mediated by the C1q globular domain, which senses unesterified fatty acids generated by cholesterol esterase. The potential implications of these findings in atherogenesis are discussed.

  19. Novel Evasion Mechanisms of the Classical Complement Pathway.

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    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.

  20. The classical and alternative pathways of complement activation play distinct roles in spontaneous C3 fragment deposition and membrane attack complex (MAC) formation on human B lymphocytes

    DEFF Research Database (Denmark)

    Leslie, Robert Graham Quinton; Nielsen, Claus Henrik

    2004-01-01

    The contributions of the classical (CP) and alternative (AP) pathways of complement activation to the spontaneous deposition of C3 fragments and the formation of membrane attack complexes (MAC) on human B lymphocytes, were assessed by incubating peripheral blood mononuclear cells with autologous ...... of MAC formation was also found to be highly pathway dependent, with the AP being about 15-fold more efficient at initiating this process than the CP. A model accounting for the effectiveness of the AP in both preserving C3 fragment integrity and initiating MAC is presented....

  1. Structural Basis for the Function of Complement Component C4 within the Classical and Lectin Pathways of Complement

    DEFF Research Database (Denmark)

    Mortensen, Sofia; Kidmose, Rune Thomas; Petersen, Steen Vang;

    2015-01-01

    Complement component C4 is a central protein in the classical and lectin pathways within the complement system. During activation of complement, its major fragment C4b becomes covalently attached to the surface of pathogens and altered self-tissue, where it acts as an opsonin marking the surface...... for removal. Moreover, C4b provides a platform for assembly of the proteolytically active convertases that mediate downstream complement activation by cleavage of C3 and C5. In this article, we present the crystal and solution structures of the 195-kDa C4b. Our results provide the molecular details...

  2. Biophysical mechanisms complementing "classical" cell biology.

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    Funk, Richard H W

    2018-01-01

    This overview addresses phenomena in cell- and molecular biology which are puzzling by their fast and highly coordinated way of organization. Generally, it appears that informative processes probably involved are more on the biophysical than on the classical biochemical side. The coordination problem is explained within the first part of the review by the topic of endogenous electrical phenomena. These are found e.g. in fast tissue organization and reorganization processes like development, wound healing and regeneration. Here, coupling into classical biochemical signaling and reactions can be shown by modern microscopy, electronics and bioinformatics. Further, one can follow the triggered reactions seamlessly via molecular biology till into genetics. Direct observation of intracellular electric processes is very difficult because of e.g. shielding through the cell membrane and damping by other structures. Therefore, we have to rely on photonic and photon - phonon coupling phenomena like molecular vibrations, which are addressed within the second part. Molecules normally possess different charge moieties and thus small electromagnetic (EMF) patterns arise during molecular vibration. These patterns can now be measured best within the optical part of the spectrum - much less in the lower terahertz till kHz and lower Hz part (third part of this review). Finally, EMFs facilitate quantum informative processes in coherent domains of molecular, charge and electron spin motion. This helps to coordinate such manifold and intertwined processes going on within cells, tissues and organs (part 4). Because the phenomena described in part 3 and 4 of the review still await really hard proofs we need concerted efforts and a combination of biophysics, molecular biology and informatics to unravel the described mysteries in "physics of life".

  3. Structural Basis for the Function of Complement Component C4 within the Classical and Lectin Pathways of Complement

    DEFF Research Database (Denmark)

    Mortensen, Sofia; Kidmose, Rune Thomas; Petersen, Steen Vang;

    2015-01-01

    Complement component C4 is a central protein in the classical and lectin pathways within the complement system. During activation of complement, its major fragment C4b becomes covalently attached to the surface of pathogens and altered self-tissue, where it acts as an opsonin marking the surface...... for removal. Moreover, C4b provides a platform for assembly of the proteolytically active convertases that mediate downstream complement activation by cleavage of C3 and C5. In this article, we present the crystal and solution structures of the 195-kDa C4b. Our results provide the molecular details...... of substrate recognition. We propose an overall molecular model for the classical pathway C5 convertase in complex with C5, suggesting that C3b increases the affinity for the substrate by inducing conformational changes in C4b rather than a direct interaction with C5. C4b-specific features revealed by our...

  4. Material properties in complement activation

    DEFF Research Database (Denmark)

    Moghimi, S. Moein; Andersen, Alina Joukainen; Ahmadvand, Davoud

    2011-01-01

    -immune performance’ relationship studies in nanomedicine research at many fronts. The interaction between nanomaterials and the complement system is complex and regulated by inter-related factors that include nanoscale size, morphology and surface characteristics. Each of these parameters may affect complement...... activation differently and through different sensing molecules and initiation pathways. The importance of material properties in triggering complement is considered and mechanistic aspects discussed. Mechanistic understanding of complement events could provide rational approaches for improved material design...

  5. SALO, a novel classical pathway complement inhibitor from saliva of the sand fly Lutzomyia longipalpis

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    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

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

    Directory of Open Access Journals (Sweden)

    Zhao-Hua Zhou

    Full Text Available 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.

  7. Activation of Complement Following Total Hip Replacement.

    Science.gov (United States)

    Thordardottir, S; Vikingsdottir, T; Bjarnadottir, H; Jonsson, H; Gudbjornsson, B

    2016-03-01

    The aim of this study was to investigate whether complement activation, via the classical and alternative pathways, occurs following a cemented total hip replacement (THR) surgery due to osteoarthritis. Blood samples were collected systematically from 12 patients - six male and six women, with a median age of 75 (range: 59-90 years) - preoperatively, 6 h post-operatively and on the first, second and third post-operative day. Total function of classical (CH50) and alternative pathways (AH50) was evaluated, along with the determination of serum concentrations of the complement proteins C3, C4, C3d, the soluble terminal complement complex (sTCC) sC5b-9, as well as C-reactive protein (CRP) and albumin. Measurements of CRP and albumin levels elucidated a marked inflammatory response following the operation. The CH50, AH50 and C3 and C4 levels were significantly lower 6 h after the surgery compared with the preoperative levels, but elevated above the preoperative levels during the following 3 days. The complement activation product C3d levels increased continually during the whole observation period, from 13.5 AU/ml (range: 8-19 AU/ml) preoperative to 20 AU/ml (range: 12-34 AU/ml) on the third post-operative day. Furthermore, we observed an increase in the sC5b-9 levels between the preoperative and the third post-operative day. These results demonstrate a significant activation of the complement system following cemented THR. Further studies are needed to elucidate the time frame and the pathogenic role of this observed complement activation.

  8. Alzheimer's beta-amyloid peptides can activate the early components of complement classical pathway in a C1q-independent manner.

    Science.gov (United States)

    Bergamaschini, L; Canziani, S; Bottasso, B; Cugno, M; Braidotti, P; Agostoni, A

    1999-03-01

    beta-Amyloid (beta-A) accumulates in the brain of patients with Alzheimer's disease (AD) and is presumably involved in the pathogenesis of this disease, on account of its neurotoxicity and complement-activating ability. Although assembly of beta-A in particular aggregates seems to be crucial, soluble non-fibrillar beta-A may also be involved. Non-fibrillar beta-A does not bind C1q, so we investigated alternative mechanisms of beta-A-dependent complement activation in vitro. On incubation with normal human plasma, non-fibrillar beta-A 1-42, and truncated peptide 1-28, induced dose-dependent activation of C1s and C4, sparing C3, as assessed by densitometric analysis of immunostained membrane after SDS-PAGE and Western blotting. The mechanism of C4 activation was not dependent on C1q, because non-fibrillar beta-A can still activate C1s and C4 in plasma genetically deficient in C1q (C1qd). In Factor XII-deficient plasma (F.XIId) the amount of cleaved C4 was about 5-10% less that in C1qd and in normal EDTA plasma; the reconstitution of F.XIId plasma with physiologic concentrations of F.XII resulted in an increased (8-15%) beta-A-dependent cleavage of C4. Thus our results indicate that the C1q-independent activation of C1 and C4 can be partially mediated by the activation products of contact system. Since the activation of contact system and of C4 leads to generation of several humoral inflammatory peptides, non-fibrillar beta-A might play a role in initiating the early inflammatory reactions leading to a multistep cascade contributing to neuronal and clinical dysfunction of AD brain.

  9. Alzheimer's β-amyloid peptides can activate the early components of complement classical pathway in a C1q-independent manner

    Science.gov (United States)

    Bergamaschini, L; Canziani, S; Bottasso, B; Cugno, M; Braidotti, P; Agostoni, A

    1999-01-01

    β-Amyloid (β-A) accumulates in the brain of patients with Alzheimer's disease (AD) and is presumably involved in the pathogenesis of this disease, on account of its neurotoxicity and complement-activating ability. Although assembly of β-A in particular aggregates seems to be crucial, soluble non-fibrillar β-A may also be involved. Non-fibrillar β-A does not bind C1q, so we investigated alternative mechanisms of β-A-dependent complement activation in vitro. On incubation with normal human plasma, non-fibrillar β-A 1-42, and truncated peptide 1–28, induced dose-dependent activation of C1s and C4, sparing C3, as assessed by densitometric analysis of immunostained membrane after SDS–PAGE and Western blotting. The mechanism of C4 activation was not dependent on C1q, because non-fibrillar β-A can still activate C1s and C4 in plasma genetically deficient in C1q (C1qd). In Factor XII-deficient plasma (F.XIId) the amount of cleaved C4 was about 5–10% less that in C1qd and in normal EDTA plasma; the reconstitution of F.XIId plasma with physiologic concentrations of F.XII resulted in an increased (8–15%) β-A-dependent cleavage of C4. Thus our results indicate that the C1q-independent activation of C1 and C4 can be partially mediated by the activation products of contact system. Since the activation of contact system and of C4 leads to generation of several humoral inflammatory peptides, non-fibrillar β-A might play a role in initiating the early inflammatory reactions leading to a multistep cascade contributing to neuronal and clinical dysfunction of AD brain. PMID:10193429

  10. MINI-REVIEW: SYSTEMIC LUPUS ERYTHEMATOSUS AND DEFICIENCIES OF EARLY COMPONENTS OF THE COMPLEMENT CLASSICAL PATHWAY

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    Lourdes eIsaac

    2016-02-01

    Full Text Available The complement system plays an important role in the innate and acquired immune response against pathogens. It consists of more than 30 proteins found in soluble form or attached to cell membranes. Most complement proteins circulate in inactive forms and can be sequentially activated by the Classical, Alternative or Lectin Pathways. Biological functions such as opsonization, removal of apoptotic cells, adjuvant function, activation of B lymphocytes, degranulation of mast cells and basophils, solubilization and clearance of immune complex and cell lysis are dependent on complement activation. Although the activation of the complement system is important to avoid infections, it also can contribute to the inflammatory response triggered by immune complex deposition in tissues in auto-immune diseases. Paradoxically, the deficiency of early complement proteins from the Classical Pathway is strongly associated with development of systemic lupus erythematous (SLE - mainly C1q deficiency (93% and C4 deficiency (75%. The aim of this review is to focus on the deficiencies of early components of the Classical Pathway (C1q, C1r, C1s, C4, C2 proteins in SLE patients.

  11. Complement Activation Alters Platelet Function

    Science.gov (United States)

    2015-12-01

    Award Number: W81XWH-12-1-0523 TITLE: Complement Activation Alters Platelet Function PRINCIPAL INVESTIGATOR: George Tsokos, M.D. CONTRACTING...Activation Alters Platelet Function 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-12-1-0523 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) George Tsokos, M.D...a decreased level of disease. Further studies will expand upon these observations better outlining the function of platelets in the injury associated

  12. Complement activation in experimental human malaria infection.

    NARCIS (Netherlands)

    Roestenberg, M.; McCall, M.B.B.; Mollnes, T.E.; Deuren, M. van; Sprong, T.; Klasen, I.S.; Hermsen, C.C.; Sauerwein, R.W.; Ven, A.J.A.M. van der

    2007-01-01

    The objective of this study was to investigate complement activation in uncomplicated, early phases of human malaria. Fifteen healthy volunteers were experimentally infected with Plasmodium falciparum malaria. Parasitemia and complement activation products were assessed. During blood stage parasitem

  13. Complement receptor 2-mediated targeting of complement inhibitors to sites of complement activation.

    Science.gov (United States)

    Song, Hongbin; He, Chun; Knaak, Christian; Guthridge, Joel M; Holers, V Michael; Tomlinson, Stephen

    2003-06-01

    In a strategy to specifically target complement inhibitors to sites of complement activation and disease, recombinant fusion proteins consisting of a complement inhibitor linked to a C3 binding region of complement receptor (CR) 2 were prepared and characterized. Natural ligands for CR2 are C3 breakdown products deposited at sites of complement activation. Fusion proteins were prepared consisting of a human CR2 fragment linked to either the N terminus or C terminus of soluble forms of the membrane complement inhibitors decay accelerating factor (DAF) or CD59. The targeted complement inhibitors bound to C3-opsonized cells, and all were significantly more effective (up to 20-fold) than corresponding untargeted inhibitors at protecting target cells from complement. CR2 fusion proteins also inhibited CR3-dependent adhesion of U937 cells to C3 opsonized erythrocytes, indicating a second potential anti-inflammatory mechanism of CR2 fusion proteins, since CR3 is involved in endothelial adhesion and diapedesis of leukocytes at inflammatory sites. Finally, the in vivo validity of the targeting strategy was confirmed by the demonstration that CR2-DAF, but not soluble DAF, targets to the kidney in mouse models of lupus nephritis that are associated with renal complement deposition.

  14. Non-specific adsorption of complement proteins affects complement activation pathways of gold nanomaterials.

    Science.gov (United States)

    Quach, Quang Huy; Kah, James Chen Yong

    2017-04-01

    The complement system is a key humoral component of innate immunity, serving as the first line of defense against intruders, including foreign synthetic nanomaterials. Although gold nanomaterials (AuNMs) are widely used in nanomedicine, their immunological response is not well understood. Using AuNMs of three shapes commonly used in biomedical applications: spherical gold nanoparticles, gold nanostars and gold nanorods, we demonstrated that AuNMs activated whole complement system, leading to the formation of SC5b-9 complex. All three complement pathways were simultaneously activated by all the AuNMs. Recognition molecules of the complement system interacted with all AuNMs in vitro, except for l-ficolin, but the correlation between these interactions and corresponding complement pathway activation was only observed in the classical and alternative pathways. We also observed the mediating role of complement activation in cellular uptake of all AuNMs by human U937 promonocytic cells, which expresses complement receptors. Taken together, our results highlighted the potential immunological challenges for clinical applications of AuNMs that were often overlooked.

  15. Complement inhibitory and anticoagulant activities of fractionated heparins

    NARCIS (Netherlands)

    Hennink, W.E.; Klerx, J.P.A.M.; Dijk, H. van; Feijen, J.

    1984-01-01

    Almost monodisperse heparin fractions (w/n < 1.1) were obtained by gel filtration of a commercial heparin. These fractions were assayed for anticoagulant activity (thrombin times and APTT), chromogenic anti-factor Xa activity, inhibitory activity for the human classical complement pathway, carboxyl

  16. Complement activation promotes muscle inflammation during modified muscle use

    Science.gov (United States)

    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.

  17. Complement system part I - molecular mechanisms of activation and regulation

    Directory of Open Access Journals (Sweden)

    Nicolas eMerle

    2015-06-01

    Full Text Available 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.

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

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    Julia A Sharp

    Full Text Available 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.

  19. Complement activation by Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Jensen, E T; Kharazmi, A; Garred, P

    1993-01-01

    In chronic infections, such as the bronchopulmonary Pseudomonas aeruginosa infection in cystic fibrosis (CF) patients, bacteria persist despite an intact host immune defense and frequent antibiotic treatment. An important reason for the persistence of the bacteria is their capacity for the biofilm...... mode of growth. In this study we investigated the role of biofilms in activation of complement, a major contributor to the inflammatory process. Complement activation by P. aeruginosa was examined in a complement consumption assay, production of C3 and factor B conversion products assessed by crossed...... immuno-electrophoresis, C5a generation tested by a PMN chemotactic assay, and terminal complement complex formation measured by ELISA. Two of the four assays showed that P. aeruginosa grown in biofilm activated complement less than planktonic bacteria, and all assays showed that activation by intact...

  20. Properdin in complement activation and tissue injury.

    Science.gov (United States)

    Lesher, Allison M; Nilsson, Bo; Song, Wen-Chao

    2013-12-15

    The plasma protein properdin is the only known positive regulator of complement activation. Although regarded as an initiator of the alternative pathway of complement activation at the time of its discovery more than a half century ago, the role and mechanism of action of properdin in the complement cascade has undergone significant conceptual evolution since then. Despite the long history of research on properdin, however, new insight and unexpected findings on the role of properdin in complement activation, pathogen infection and host tissue injury are still being revealed by ongoing investigations. In this article, we provide a brief review on recent studies that shed new light on properdin biology, focusing on the following three topics: (1) its role as a pattern recognition molecule to direct and trigger complement activation, (2) its context-dependent requirement in complement activation on foreign and host cell surfaces, and (3) its involvement in alternative pathway complement-mediated immune disorders and considerations of properdin as a potential therapeutic target in human diseases.

  1. Complement activation and inhibition: a delicate balance

    DEFF Research Database (Denmark)

    Sjöberg, A P; Trouw, L A; Blom, A M

    2009-01-01

    Complement is part of the innate immune defence and not only recognizes microbes but also unwanted host molecules to enhance phagocytosis and clearance. This process of opsonisation must be tightly regulated to prevent immunopathology. Endogenous ligands such as dying cells, extracellular matrix...... activation. Disturbances to the complement regulation on endogenous ligands can lead to diseases such as age-related macular degeneration, neurological and rheumatic disorders. A thorough understanding of these processes might be crucial to developing new therapeutic strategies....

  2. Functional analysis of Ficolin-3 mediated complement activation

    DEFF Research Database (Denmark)

    Hein, Estrid; Honoré, Christian; Skjoedt, Mikkel-Ole

    2010-01-01

    assessed by C4, C3 and terminal complement complex (TCC) deposition. Serum Ficolin-3 bound to acBSA in a calcium dependent manner, while only minimal binding of Ficolin-2 and no binding of Ficolin-1 were observed. No binding to normal BSA was seen for any of the Ficolins. Serum C4, C3 and TCC deposition...... was applied to the samples that inhibited interference from the classical pathway due to the presence of anti-BSA antibodies in some sera. We describe a novel functional method for measuring complement activation mediated by Ficolin-3 in human serum up to the formation of TCC. The assay provides...

  3. C1q, the classical complement pathway protein binds Hirano bodies in Pick's disease.

    Science.gov (United States)

    Singhrao, Sim K

    2013-06-01

    Haematoxylin/Eosin staining was performed to screen for Hirano bodies from the temporal lobe including the hippocampus in 10 Pick's disease cases containing Pick bodies. Although the inclusions were confirmed in 9 out of 10 cases, only 4 out of 10 were particularly enriched with the eosinophilic bodies. These were subjected to immunostaining with anticomplement antibodies and astrocyte marker antiglial fibrillary acidic protein antibody and the HLA class II CR3/43 antibody to visualize microglia. An intraneuronal Hirano body was observed in one case that otherwise contained mainly the extracellular inclusions. In all cases, the extracellular Hirano bodies were seen lying adjacent to soma of neurons within CA1 region of the hippocampus. The extracellular Hirano bodies stained intensely with C1q, the first component of the classical pathway of activation but remained unreactive against antibodies to C4 and the C3 activation products (C3b and iC3b) and the alternative complement pathway component factor B. Hirano bodies also remained negative with the antiglial fibrillary acidic protein for astrocytes and HLA class II antibody CR3/43 for microglia. The results demonstrate that Hirano bodies have strong immunoreactivity to C1q; however, whether other complement components are associated with these inclusions remains to be further investigated.

  4. Micrurus snake venoms activate human complement system and generate anaphylatoxins

    Directory of Open Access Journals (Sweden)

    Tanaka Gabriela D

    2012-01-01

    Full Text Available Abstract Background The genus Micrurus, coral snakes (Serpentes, Elapidae, comprises more than 120 species and subspecies distributed from the south United States to the south of South America. Micrurus snake bites can cause death by muscle paralysis and further respiratory arrest within a few hours after envenomation. Clinical observations show mainly neurotoxic symptoms, although other biological activities have also been experimentally observed, including cardiotoxicity, hemolysis, edema and myotoxicity. Results In the present study we have investigated the action of venoms from seven species of snakes from the genus Micrurus on the complement system in in vitro studies. Several of the Micrurus species could consume the classical and/or the lectin pathways, but not the alternative pathway, and C3a, C4a and C5a were generated in sera treated with the venoms as result of this complement activation. Micrurus venoms were also able to directly cleave the α chain of the component C3, but not of the C4, which was inhibited by 1,10 Phenanthroline, suggesting the presence of a C3α chain specific metalloprotease in Micrurus spp venoms. Furthermore, complement activation was in part associated with the cleavage of C1-Inhibitor by protease(s present in the venoms, which disrupts complement activation control. Conclusion Micrurus venoms can activate the complement system, generating a significant amount of anaphylatoxins, which may assist due to their vasodilatory effects, to enhance the spreading of other venom components during the envenomation process.

  5. Functional analysis of Ficolin-3 mediated complement activation.

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    Estrid Hein

    Full Text Available The recognition molecules of the lectin complement pathway are mannose-binding lectin and Ficolin -1, -2 and -3. Recently deficiency of Ficolin-3 was found to be associated with life threatening infections. Thus, we aimed to develop a functional method based on the ELISA platform for evaluating Ficolin-3 mediated complement activation that could be applicable for research and clinical use. Bovine serum albumin (BSA was acetylated (acBSA and chosen as a solid phase ligand for Ficolins in microtiter wells. Binding of Ficolins on acBSA was evaluated, as was functional complement activation assessed by C4, C3 and terminal complement complex (TCC deposition. Serum Ficolin-3 bound to acBSA in a calcium dependent manner, while only minimal binding of Ficolin-2 and no binding of Ficolin-1 were observed. No binding to normal BSA was seen for any of the Ficolins. Serum C4, C3 and TCC deposition on acBSA were dependent only on Ficolin-3 in appropriate serum dilutions. Deposition of down stream complement components correlated highly significantly with the serum concentration of Ficolin-3 but not with Ficolin-2 in healthy donors. To make the assay robust for clinical use a chemical compound was applied to the samples that inhibited interference from the classical pathway due to the presence of anti-BSA antibodies in some sera. We describe a novel functional method for measuring complement activation mediated by Ficolin-3 in human serum up to the formation of TCC. The assay provides the possibility to diagnose functional and genetic defects of Ficolin-3 and down stream components in the lectin complement pathway.

  6. Solution Structures of Complement C2 and its C4 Complexes Propose Pathway Specific Mechanisms for Control and Activation of the Complement Proconvertases

    DEFF Research Database (Denmark)

    Mortensen, Sofia; Jensen, Jan Kristian; Andersen, Gregers Rom

    2016-01-01

    The lectin (LP) and classical (CP) pathways are two of the three main activation cascades of the complement system. These pathways start with recognition of different pathogen- or danger-associated molecular patterns and include identical steps of proteolytic activation of complement component C4...

  7. Complement Component C3 Binds to Activated Normal Platelets without Preceding Proteolytic Activation and Promotes Binding to Complement Receptor 1

    NARCIS (Netherlands)

    O.A. Hamad; P.H. Nilsson; D. Wouters; J.D. Lambris; K.N. Ekdahl; B. Nilsson

    2010-01-01

    It has been reported that complement is activated on the surface of activated platelets, despite the presence of multiple regulators of complement activation. To reinvestigate the mechanisms by which activated platelets bind to complement components, the presence of complement proteins on the surfac

  8. Adenovirus Activates Complement by Distinctly Different Mechanisms In Vitro and In Vivo: Indirect Complement Activation by Virions In Vivo▿

    OpenAIRE

    Tian, Jie; Xu, Zhili; Jeffrey S Smith; Hofherr, Sean E.; Barry, Michael A.; Byrnes, Andrew P.

    2009-01-01

    Understanding innate immunity is key to improving the safety of adenovirus (Ad) vectors for systemic gene therapy. Ad has been shown to activate complement in vitro, but activation of complement after Ad injection in vivo has not been directly measured. Using complement protein C3a as a marker of complement activation, we show that types 2 and 5 human Ads cause rapid complement activation after intravenous injection in mice. Unexpectedly, the mechanisms in vivo were different than those in vi...

  9. Complement activation in chromosome 13 dementias

    DEFF Research Database (Denmark)

    Rostagno, A.; Revesz, T.; Lashley, T.;

    2002-01-01

    stable complexes in physiological conditions. Activation proceeds ∼70–75% through the classical pathway while only ∼25–30% seems to occur through the alternative pathway. The data suggest that the chronic inflammatory response generated by the amyloid peptides in vivo might be a contributing factor...

  10. Human L-ficolin, a recognition molecule of the lectin activation pathway of complement, activates complement by binding to pneumolysin, the major toxin of Streptococcus pneumoniae.

    Science.gov (United States)

    Ali, Youssif M; Kenawy, Hany I; Muhammad, Adnan; Sim, Robert B; Andrew, Peter W; Schwaeble, Wilhelm J

    2013-01-01

    The complement system is an essential component of the immune response, providing a critical line of defense against different pathogens including S. pneumoniae. Complement is activated via three distinct pathways: the classical (CP), the alternative (AP) and the lectin pathway (LP). The role of Pneumolysin (PLY), a bacterial toxin released by S. pneumoniae, in triggering complement activation has been studied in vitro. Our results demonstrate that in both human and mouse sera complement was activated via the CP, initiated by direct binding of even non-specific IgM and IgG3 to PLY. Absence of CP activity in C1q(-/-) mouse serum completely abolished any C3 deposition. However, C1q depleted human serum strongly opsonized PLY through abundant deposition of C3 activation products, indicating that the LP may have a vital role in activating the human complement system on PLY. We identified that human L-ficolin is the critical LP recognition molecule that drives LP activation on PLY, while all of the murine LP recognition components fail to bind and activate complement on PLY. This work elucidates the detailed interactions between PLY and complement and shows for the first time a specific role of the LP in PLY-mediated complement activation in human serum.

  11. Using animal models to determine the significance of complement activation in Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Loeffler David A

    2004-10-01

    Full Text Available Abstract Complement inflammation is a major inflammatory mechanism whose function is to promote the removal of microorganisms and the processing of immune complexes. Numerous studies have provided evidence for an increase in this process in areas of pathology in the Alzheimer's disease (AD brain. Because complement activation proteins have been demonstrated in vitro to exert both neuroprotective and neurotoxic effects, the significance of this process in the development and progression of AD is unclear. Studies in animal models of AD, in which brain complement activation can be experimentally altered, should be of value for clarifying this issue. However, surprisingly little is known about complement activation in the transgenic animal models that are popular for studying this disorder. An optimal animal model for studying the significance of complement activation on Alzheimer's – related neuropathology should have complete complement activation associated with senile plaques, neurofibrillary tangles (if present, and dystrophic neurites. Other desirable features include both classical and alternative pathway activation, increased neuronal synthesis of native complement proteins, and evidence for an increase in complement activation prior to the development of extensive pathology. In order to determine the suitability of different animal models for studying the role of complement activation in AD, the extent of complement activation and its association with neuropathology in these models must be understood.

  12. Acidosis activates complement system in vitro

    Directory of Open Access Journals (Sweden)

    Michael Emeis

    1998-01-01

    Full Text Available We investigated the in vitro effect of different form s of acidosis (pH 7.0 on the formation of anaphylatoxins C3a and C5a. Metabolic acidosis due to addition of hydrochloric acid (10 μ mol/ml blood or lactic acid (5.5 μ mol/ml to heparin blood (N=12 caused significant activation of C3a and C5a compared to control (both p=0.002. Respiratory acidosis activated C3a (p=0.007 and C5a (p=0.003 compared to normocapnic controls. Making blood samples with lactic acidosis hypocapnic resulted in a median pH of 7.37. In this respiratory compensated metabolic acidosis, C3a and C5a were not increased. These experiments show that acidosis itself and not lactate trigger for activation of complement components C3 and C5.

  13. Acidosis activates complement system in vitro.

    Science.gov (United States)

    Emeis, M; Sonntag, J; Willam, C; Strauss, E; Walka, M M; Obladen, M

    1998-01-01

    We investigated the in vitro effect of different forms of acidosis (pH 7.0) on the formation of anaphylatoxins C3a and C5a. Metabolic acidosis due to addition of hydrochloric acid (10 micromol/ml blood) or lactic acid (5.5 micromol/ml) to heparin blood (N=12) caused significant activation of C3a and C5a compared to control (both p=0.002). Respiratory acidosis activated C3a (p=0.007) and C5a (p=0.003) compared to normocapnic controls. Making blood samples with lactic acidosis hypocapnic resulted in a median pH of 7.37. In this respiratory compensated metabolic acidosis, C3a and C5a were not increased. These experiments show that acidosis itself and not lactate trigger for activation of complement components C3 and C5. PMID:9927235

  14. Differences in complement activation between complement-resistant and complement-sensitive Moraxella (Branhamella) catarrhalis strains occur at the level of membrane attack complex formation.

    OpenAIRE

    Verduin, C.M.; Jansze, M.; Hol, C; Mollnes, T E; Verhoef, J; Van Dijk, H.

    1994-01-01

    The mechanism of resistance to human complement-mediated killing in Moraxella catarrhalis was studied by comparing different complement-sensitive and complement-resistant M. catarrhalis strains in a functional bystander hemolysis assay and an enzyme-linked immunosorbent assay (ELISA) for soluble terminal complement complexes. Complement-resistant stains appeared to activate complement to the same extent as, or even slightly better than, complement-sensitive strains. This indicates that comple...

  15. The epidermal growth factor receptor is a regulator of epidermal complement component expression and complement activation

    DEFF Research Database (Denmark)

    Abu-Humaidan, Anas H A; Ananthoju, Nageshwar; Mohanty, Tirthankar;

    2014-01-01

    The complement system is activated in response to tissue injury. During wound healing, complement activation seems beneficial in acute wounds but may be detrimental in chronic wounds. We found that the epidermal expression of many complement components was only increased to a minor extent in skin...... wounds in vivo and in cultured keratinocytes after exposure to supernatant from stimulated mononuclear cells. In contrast, the epidermal expression of complement components was downregulated in ex vivo injured skin lacking the stimulation from infiltrating inflammatory cells but with intact injury......-induced epidermal growth factor receptor (EGFR)-mediated growth factor response. In cultured primary keratinocytes, stimulation with the potent EGFR ligand, TGF-α, yielded a significant downregulation of complement component expression. Indeed, EGFR inhibition significantly enhanced the induction of complement...

  16. Complement activation by tubular cells is mediated by properdin binding

    NARCIS (Netherlands)

    Gaarkeuken, E.M.; Siezenga, M.A.; Zuidwijk, K.; Kooten, C. van; Rabelink, T.J.; Daha, M.R.; Berger, S.P.

    2008-01-01

    Activation of filtered complement products on the brush border of the tubular epithelium is thought to be a key factor underlying proteinuria-induced tubulointerstitial injury. However, the mechanism of tubular complement activation is still unclear. Recent studies on mechanisms of complement activa

  17. Factor H-related proteins determine complement-activating surfaces.

    Science.gov (United States)

    Józsi, Mihály; Tortajada, Agustin; Uzonyi, Barbara; Goicoechea de Jorge, Elena; Rodríguez de Córdoba, Santiago

    2015-06-01

    Complement factor H-related proteins (FHRs) are strongly associated with different diseases involving complement dysregulation, which suggests a major role for these proteins regulating complement activation. Because FHRs are evolutionarily and structurally related to complement inhibitor factor H (FH), the initial assumption was that the FHRs are also negative complement regulators. Whereas weak complement inhibiting activities were originally reported for these molecules, recent developments indicate that FHRs may enhance complement activation, with important implications for the role of these proteins in health and disease. We review these findings here, and propose that FHRs represent a complex set of surface recognition molecules that, by competing with FH, provide improved discrimination of self and non-self surfaces and play a central role in determining appropriate activation of the complement pathway.

  18. Dimerization of complement factor H-related proteins modulates complement activation in vivo.

    Science.gov (United States)

    Goicoechea de Jorge, Elena; Caesar, Joseph J E; Malik, Talat H; Patel, Mitali; Colledge, Matthew; Johnson, Steven; Hakobyan, Svetlana; Morgan, B Paul; Harris, Claire L; Pickering, Matthew C; Lea, Susan M

    2013-03-19

    The complement system is a key component regulation influences susceptibility to age-related macular degeneration, meningitis, and kidney disease. Variation includes genomic rearrangements within the complement factor H-related (CFHR) locus. Elucidating the mechanism underlying these associations has been hindered by the lack of understanding of the biological role of CFHR proteins. Here we present unique structural data demonstrating that three of the CFHR proteins contain a shared dimerization motif and that this hitherto unrecognized structural property enables formation of both homodimers and heterodimers. Dimerization confers avidity for tissue-bound complement fragments and enables these proteins to efficiently compete with the physiological complement inhibitor, complement factor H (CFH), for ligand binding. Our data demonstrate that these CFHR proteins function as competitive antagonists of CFH to modulate complement activation in vivo and explain why variation in the CFHRs predisposes to disease.

  19. Neurons express proteins of the classical complement pathway in Alzheimer disease.

    Science.gov (United States)

    Terai, K; Walker, D G; McGeer, E G; McGeer, P L

    1997-09-26

    Occurrence of the classical pathway complement proteins C1q, C1r, C1s, C2, C3, C4, C5, C6, C7, C8 and C9 was studied in human hippocampus and temporal cortex by immunohistochemistry and Western blotting. In Alzheimer disease (AD) cases, positive staining for all of these proteins was observed in pyramidal neurons and senile plaques. In control cases, weaker pyramidal neuron staining was observed except for C1q and C1s which were not detected. On Western blots of AD hippocampal extracts, bands corresponding to those detected in normal serum were found for each of the complement proteins. Comparable bands were also detected in normal hippocampal extracts with the exception of C1s which was not observed. The intensity of the bands was generally stronger in AD than in normal extracts, but, in the latter, there was considerable variability between cases and between bands in a single case. These data suggest that pyramidal neurons may be a source of the complement components known to be associated with Alzheimer lesions.

  20. Hepatitis C virus NS3/4A protease inhibits complement activation by cleaving complement component 4.

    Directory of Open Access Journals (Sweden)

    Seiichi Mawatari

    Full Text Available BACKGROUND: It has been hypothesized that persistent hepatitis C virus (HCV infection is mediated in part by viral proteins that abrogate the host immune response, including the complement system, but the precise mechanisms are not well understood. We investigated whether HCV proteins are involved in the fragmentation of complement component 4 (C4, composed of subunits C4α, C4β, and C4γ, and the role of HCV proteins in complement activation. METHODS: Human C4 was incubated with HCV nonstructural (NS 3/4A protease, core, or NS5. Samples were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and then subjected to peptide sequencing. The activity of the classical complement pathway was examined using an erythrocyte hemolysis assay. The cleavage pattern of C4 in NS3/4A-expressing and HCV-infected cells, respectively, was also examined. RESULTS: HCV NS3/4A protease cleaved C4γ in a concentration-dependent manner, but viral core and NS5 did not. A specific inhibitor of NS3/4A protease reduced C4γ cleavage. NS3/4A protease-mediated cleavage of C4 inhibited classical pathway activation, which was abrogated by a NS3/4A protease inhibitor. In addition, co-transfection of cells with C4 and wild-type NS3/4A, but not a catalytic-site mutant of NS3/4A, produced cleaved C4γ fragments. Such C4 processing, with a concomitant reduction in levels of full-length C4γ, was also observed in HCV-infected cells expressing C4. CONCLUSIONS: C4 is a novel cellular substrate of the HCV NS3/4A protease. Understanding disturbances in the complement system mediated by NS3/4A protease may provide new insights into the mechanisms underlying persistent HCV infection.

  1. Solar Activity and Classical Physics

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This review of solar physics emphasizes several of the more conspicuous scientific puzzles posed by contemporary observational knowledge of the magnetic activity of the Sun. The puzzles emphasize how much classical physics we have yet to learn from the Sun. The physics of solar activity is based on the principles of Newton, Maxwell, Lorentz, Boltzmann, et. al., along with the principles of radiative transfer. In the large, these principles are expressed by magnetohydrodynamics. A brief derivation of the magnetohydrodynamic induction and momentum equations is provided, with a discussion of popular misconceptions.

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

    Science.gov (United States)

    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

  3. Direct evidence of complement activation in HELLP syndrome: A link to atypical hemolytic uremic syndrome.

    Science.gov (United States)

    Vaught, Arthur J; Gavriilaki, Eleni; Hueppchen, Nancy; Blakemore, Karin; Yuan, Xuan; Seifert, Sara M; York, Sarah; Brodsky, Robert A

    2016-05-01

    HELLP syndrome (hemolysis, elevated liver enzymes, and low platelets) is a severe variant of pre-eclampsia whose pathogenesis remains unclear. Recent evidence and clinical similarities suggest a link to atypical hemolytic uremic syndrome, a disease of excessive activation of the alternative complement pathway effectively treated with a complement inhibitor, eculizumab. Therefore, we used a functional complement assay, the modified Ham test, to analyze sera of women with classic or atypical HELLP syndrome, pre-eclampsia with severe features, normal pregnancies, and healthy nonpregnant women. Sera were also evaluated using levels of the terminal product of complement activation (C5b-9). We tested the in vitro ability of eculizumab to inhibit complement activation in HELLP serum. Increased complement activation was observed in participants with classic or atypical HELLP compared with those with normal pregnancies and nonpregnant controls. Mixing HELLP serum with eculizumab-containing serum resulted in a significant decrease in cell killing compared with HELLP serum alone. We found that HELLP syndrome is associated with increased complement activation as assessed with the modified Ham test. This assay may aid in the diagnosis of HELLP syndrome and could confirm that its pathophysiology is related to that of atypical hemolytic uremic syndrome.

  4. The role of complement activation in atherogenesis: the first 40 years.

    Science.gov (United States)

    Vlaicu, Sonia I; Tatomir, Alexandru; Rus, Violeta; Mekala, Armugam P; Mircea, Petru A; Niculescu, Florin; Rus, Horea

    2016-02-01

    The pathogenesis of atherosclerotic inflammation is a multi-step process defined by the interweaving of excess modified lipid particles, monocyte-macrophages populations, and innate immune and adaptive immunity effectors. A part of innate immunity, the complement system, is an important player in the induction and progression of atherosclerosis. The accumulation of either oxidized or enzymatically modified LDL-bound to C-reactive protein or not-prompts complement activation leading to the assembly of the terminal complement C5b-9 complex in the atherosclerotic lesion. The sublytic C5b-9 assembly leads to the activation and proliferation of smooth muscle and endothelial cells, accompanied by the release of various chemotactic, pro-adhesion, and procoagulant cytokines from these cells. Response gene to complement (RGC)-32, an essential effector of the terminal complement complex C5b-9, also affects atherogenesis, propelling vascular smooth muscle cell proliferation and migration, stimulating endothelial proliferation, and promoting vascular lesion formation. A substantial amount of experimental work has suggested a role for the complement system activation during atherosclerotic plaque formation, with the proximal classical complement pathway seemingly having a protective effect and terminal complement contributing to accelerated atherogenesis. All these data suggest that complement plays an important role in atherogenesis.

  5. Neuronal expression of mRNAs for complement proteins of the classical pathway in Alzheimer brain.

    Science.gov (United States)

    Shen, Y; Li, R; McGeer, E G; McGeer, P L

    1997-09-26

    To determine possible sources of complement proteins in the brain, we investigated by in situ hybridization expression of the mRNAs of C1q, C2, C3, C4, C5, C6, C7, C8 and C9 in postmortem Alzheimer disease (AD) and control brain tissue. We found detectable hybridization for all these components in the temporal cortex and hippocampus, with significantly higher levels being found in AD tissue. Hybridization signals were strongest over pyramidal neurons. Low or absent hybridization was seen in the visual cortex or cerebellum. These results suggest that the activated complement components found in association with AD lesions may be, in part, derived from neurons.

  6. Physicochemical signatures of nanoparticle-dependent complement activation

    Science.gov (United States)

    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.

  7. Complement-activated oligodendroglia: a new pathogenic entity identified by immunostaining with antibodies to human complement proteins C3d and C4d.

    Science.gov (United States)

    Yamada, T; Akiyama, H; McGeer, P L

    1990-05-04

    Clusters of oligodendroglial fibers were identified immunohistochemically in human brain tissue with antibodies to the complement proteins C3d and C4d in several neurological disorders. These included Pick's, Huntington's, Parkinson's and Alzheimer's disease, amyotrophic lateral sclerosis, progressive supranuclear palsy and Shy-Drager syndrome. These complement-activated oligodendroglia occurred in selected areas of gray and white matter. They were rarely observed in control tissue. Immunogold electron microscopy established that the C4d antibody was attached to degenerating myelin sheaths. These data indicate attachment of classical complement pathway proteins to selective oligodendroglia in several neurological disorders.

  8. Protein ultrastructure and the nanoscience of complement activation.

    Science.gov (United States)

    Vorup-Jensen, Thomas; Boesen, Thomas

    2011-09-16

    The complement system constitutes an important barrier to infection of the human body. Over more than four decades structural properties of the proteins of the complement system have been investigated with X-ray crystallography, electron microscopy, small-angle scattering, and atomic force microscopy. Here, we review the accumulated evidence that the nm-scaled dimensions and conformational changes of these proteins support functions of the complement system with regard to tissue distribution, molecular crowding effects, avidity binding, and conformational regulation of complement activation. In the targeting of complement activation to the surfaces of nanoparticulate material, such as engineered nanoparticles or fragments of the microbial cell wall, these processes play intimately together. This way the complement system is an excellent example where nanoscience may serve to unravel the molecular biology of the immune response.

  9. Systemic complement activation in age-related macular degeneration.

    Science.gov (United States)

    Scholl, Hendrik P N; Charbel Issa, Peter; Walier, Maja; Janzer, Stefanie; Pollok-Kopp, Beatrix; Börncke, Florian; Fritsche, Lars G; Chong, Ngaihang V; Fimmers, Rolf; Wienker, Thomas; Holz, Frank G; Weber, Bernhard H F; Oppermann, Martin

    2008-07-02

    Dysregulation of the alternative pathway (AP) of complement cascade has been implicated in the pathogenesis of age-related macular degeneration (AMD), the leading cause of blindness in the elderly. To further test the hypothesis that defective control of complement activation underlies AMD, parameters of complement activation in blood plasma were determined together with disease-associated genetic markers in AMD patients. Plasma concentrations of activation products C3d, Ba, C3a, C5a, SC5b-9, substrate proteins C3, C4, factor B and regulators factor H and factor D were quantified in patients (n = 112) and controls (n = 67). Subjects were analyzed for single nucleotide polymorphisms in factor H (CFH), factor B-C2 (BF-C2) and complement C3 (C3) genes which were previously found to be associated with AMD. All activation products, especially markers of chronic complement activation Ba and C3d (pAMD patients compared to controls. Similar alterations were observed in factor D, but not in C3, C4 or factor H. Logistic regression analysis revealed better discriminative accuracy of a model that is based only on complement activation markers Ba, C3d and factor D compared to a model based on genetic markers of the complement system within our study population. In both the controls' and AMD patients' group, the protein markers of complement activation were correlated with CFH haplotypes.This study is the first to show systemic complement activation in AMD patients. This suggests that AMD is a systemic disease with local disease manifestation at the ageing macula. Furthermore, the data provide evidence for an association of systemic activation of the alternative complement pathway with genetic variants of CFH that were previously linked to AMD susceptibility.

  10. Systemic complement activation in age-related macular degeneration.

    Directory of Open Access Journals (Sweden)

    Hendrik P N Scholl

    Full Text Available Dysregulation of the alternative pathway (AP of complement cascade has been implicated in the pathogenesis of age-related macular degeneration (AMD, the leading cause of blindness in the elderly. To further test the hypothesis that defective control of complement activation underlies AMD, parameters of complement activation in blood plasma were determined together with disease-associated genetic markers in AMD patients. Plasma concentrations of activation products C3d, Ba, C3a, C5a, SC5b-9, substrate proteins C3, C4, factor B and regulators factor H and factor D were quantified in patients (n = 112 and controls (n = 67. Subjects were analyzed for single nucleotide polymorphisms in factor H (CFH, factor B-C2 (BF-C2 and complement C3 (C3 genes which were previously found to be associated with AMD. All activation products, especially markers of chronic complement activation Ba and C3d (p<0.001, were significantly elevated in AMD patients compared to controls. Similar alterations were observed in factor D, but not in C3, C4 or factor H. Logistic regression analysis revealed better discriminative accuracy of a model that is based only on complement activation markers Ba, C3d and factor D compared to a model based on genetic markers of the complement system within our study population. In both the controls' and AMD patients' group, the protein markers of complement activation were correlated with CFH haplotypes.This study is the first to show systemic complement activation in AMD patients. This suggests that AMD is a systemic disease with local disease manifestation at the ageing macula. Furthermore, the data provide evidence for an association of systemic activation of the alternative complement pathway with genetic variants of CFH that were previously linked to AMD susceptibility.

  11. An assay for the mannan-binding lectin pathway of complement activation

    DEFF Research Database (Denmark)

    Petersen, Steen Vang; Thiel, S; Jensen, L;

    2001-01-01

    The mannan-binding lectin (MBL) pathway of complement activation has been established as the third pathway of complement activation. MBL is a carbohydrate-binding serum protein, which circulates in complex with serine proteases known as mannan-binding lectin associated serine proteases (MASPs...... activation. Therefore, in a generally applicable complement activation assay specific for the MBL pathway, the activity of the classical pathway must be inhibited. This can be accomplished by exploiting the finding that high ionic strength buffers inhibit the binding of C1q to immune complexes and disrupt...... the C1 complex, whereas the carbohydrate-binding activity of MBL and the integrity of the MBL complex is maintained under hypertonic conditions. In the assay described here, the specific C4b-depositing capacity of the MBL pathway was determined by incubating serum diluted in buffer containing 1 M Na...

  12. Anti-complement activity of tiliroside from the flower buds of Magnolia fargesii.

    Science.gov (United States)

    Jung, K Y; Oh, S R; Park, S H; Lee, I S; Ahn, K S; Lee, J J; Lee, H K

    1998-10-01

    As part of the search for anticomplementary active components from natural products, the anticomplementary properties of methanolic extracts from the flower buds of Magnoliafargesii have been investigated. Bioassay-guided chromatographic separation of the active constituents led to the isolation of compound 1, whose structure was identified by spectroscopic methods to be kaempferol 3-O-beta-D-(6"-O-coumaroyl)glucopyranoside (tiliroside). Tiliroside showed very potent anti-complement activity (IC50=5.4 x 10(-5) M) on the classical pathway of the complement system, even higher than rosmarinic acid, which is a well-known inhibitor against the complement system. On the other hand, the hydrolysates of tiliroside, kaempferol, astragalin and p-coumaric acid showed very weak activity on this system.

  13. Radioimmunoassay for anaphylatoxins: a sensitive method for determining complement activation products in biological fluids

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, J.L.; Hugli, T.E.

    1984-01-01

    Activation of the blood complement system generates bioactive fragments called anaphylatoxins. The three anaphylatoxins C3a, C4a, and C5a are released during classical pathway activation while only C3a and C5a are released when the alternative pathway of complement is activated. Radioimmunoassays were designed to individually detect and quantitate the activation fragments C3a, C4a, and C5a in biological fluids without interference from the precursor molecules C3, C4, and C5. Kinetics of complement activation in fresh human serum exposed to the activators zymosan, heat-aggregated immunoglobulin, or cobra venom factor were monitored using the radioimmunoassay technique. For the first time, activation of components C3, C4, and C5 was followed simultaneously in a single serum sample. Analysis of the patterns and extent of anaphylatoxin formation during activation in serum may be used to screen for deficiencies or defects in the complement cascade. Levels of the anaphylatoxins in freshly drawn serum were much higher than levels detected in EDTA-plasma. Detection of low-level complement activation in patient's blood, urine, or synovial fluid, using anaphylatoxin formation as an indicator, may prove useful in signaling numerous forms of inflammatory reactions. The demonstration of anaphylatoxins in clinical samples is being recognized as a valuable diagnostic tool in monitoring the onset of immune disease.

  14. Early intra-articular complement activation in ankle fractures

    DEFF Research Database (Denmark)

    Schmal, Hagen; Salzmann, Gian M; Niemeyer, Philipp;

    2014-01-01

    osteochondritis dissecans (OCD) of the ankle. All fractures needed external fixation during which joint effusions were collected. Fluid analysis was done by ELISA measuring aggrecan, bFGF, IL-1 β, IGF-1, and the complement components C3a, C5a, and C5b-9. The time periods between occurrence of fracture...... and OCD patients, bFGF, IGF-1, and all complement components were significantly higher concentrated in ankle joints with fractures (P Complement activation and inflammatory cell infiltration characterize the joint biology following acute ankle fractures....

  15. Complement activation and interleukin response in major abdominal surgery.

    Science.gov (United States)

    Kvarnström, A L; Sarbinowski, R T; Bengtson, J-P; Jacobsson, L M; Bengtsson, A L

    2012-05-01

    The objective of this study was to evaluate whether major abdominal surgery leads to complement activation and interleukin response and whether the kind of anaesthesia influence complement activation and the release of inflammatory interleukins. The study design was prospective and randomised. Fifty patients undergoing open major colorectal surgery due to cancer disease or inflammatory bowel disease were studied. Twenty-five patients were given total intravenous anaesthesia (TIVA) with propofol and remifentanil, and 25 patients were given inhalational anaesthesia with sevoflurane and fentanyl. To determine complement activation (C3a and SC5b-9) and the release of pro- and anti-inflammatory interleukins (tumour necrosis factor-a (TNF-a)), interleukin-1b (IL-1b), IL-6, IL-8, IL-4 and IL-10), blood samples were drawn preoperatively, 60 minutes after start of surgery, 30 minutes after end of surgery and 24 hours postoperatively. Complement was activated and pro-inflammatory interleukins (IL-6 and IL-8) and anti-inflammatory interleukins (IL-10) were released during major colorectal surgery. There was no significant difference between TIVA and inhalational anaesthesia regarding complement activation and cytokine release. Major colorectal surgery leads to activation of the complement cascade and the release of both pro-inflammatory and anti-inflammatory cytokines. There are no significant differences between total intravenous anaesthesia (TIVA) with propofol and remifentanil and inhalational anaesthesia with sevoflurane and fentanyl regarding complement activation and the release of pro- and anti-inflammatory interleukins. © 2012 The Authors. Scandinavian Journal of Immunology © 2012 Blackwell Publishing Ltd. Scandinavian Journal of Immunology.

  16. Plaque complement activation and cognitive loss in Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Camp Dianne M

    2008-03-01

    Full Text Available Abstract Background Complement activation is increased in Alzheimer's disease (AD, but its significance is unclear. The objective of this study was to determine the relationship between complement activation and cognition during the development of AD. Methods iC3b, C9, Bielschowsky, and Gallyas staining was performed on aged normal (n = 17, mild cognitively impaired (n = 12, and AD (n = 17–18 inferior temporal gyrus specimens. Plaques were counted in 10× fields with high numbers of Bielschowsky-stained plaques. One-way ANOVA was used to determine between-group differences for plaque counts and measures of cognitive function, and linear regression was used to evaluate global cognition as a function of Bielschowsky-stained plaques. Terms for iC3b- and C9-stained plaques were then added sequentially as additional predictors in a "mediation analysis" model. Results Complement was detected on plaques in all groups, and on neurofibrillary tangles only in AD specimens. iC3b, C9, and Bielschowsky-stained plaque counts increased 2.5- to 3-fold in AD vs. other groups (all p ≤ 0.01. C9 staining was present on some diffuse plaques, as well as on neuritic plaques. Bielschowsky-stained and complement-stained plaque counts were highly correlated, and were negatively correlated with cognitive measures. When the Bielschowsky plaque count was used as a predictor, its correlations with cognitive measures were statistically significant, but when iC3b and C9 plaque counts were added as additional predictors, these correlations were no longer significant. This loss of significance was attributed to multicollinearity, i.e., high correlations between Bielschowsky-stained and complement-stained plaque counts. Conclusion Both early-stage (iC3b and late-stage (C9 complement activation occurs on neocortical plaques in subjects across the cognitive spectrum; contrary to previous reports, C9 is present on some diffuse plaques. Because of high correlations between

  17. Activation of human complement by immunoglobulin G antigranulocyte antibody.

    Science.gov (United States)

    Rustagi, P K; Currie, M S; Logue, G L

    1982-01-01

    The ability of antigranulocyte antibody to fix the third component of complement (C3) to the granulocyte surface was investigated by an assay that quantitates the binding of monoclonal anti-C3 antibody to paraformaldehyde-fixed cells preincubated with Felty's syndrome serum in the presence of human complement. The sera from 7 of 13 patients with Felty's syndrome bound two to three times as much C3 to granulocytes as sera from patients with uncomplicated rheumatoid arthritis. The complement-activating ability of Felty's syndrome serum seemed to reside in the monomeric IgG-containing serum fraction. For those sera capable of activating complement, the amount of C3 fixed to granulocytes was proportional to the amount of granulocyte-binding IgG present in the serum. Thus, complement fixation appeared to be a consequence of the binding of antigranulocyte antibody to the cell surface. These studies suggest a role for complement-mediated injury in the pathophysiology of immune granulocytopenia, as has been demonstrated for immune hemolytic anemia and immune thrombocytopenia. PMID:7174786

  18. Bullous pemphigoid autoantibodies directly induce blister formation without complement activation.

    Science.gov (United States)

    Ujiie, Hideyuki; Sasaoka, Tetsumasa; Izumi, Kentaro; Nishie, Wataru; Shinkuma, Satoru; Natsuga, Ken; Nakamura, Hideki; Shibaki, Akihiko; Shimizu, Hiroshi

    2014-11-01

    Complement activation and subsequent recruitment of inflammatory cells at the dermal/epidermal junction are thought to be essential for blister formation in bullous pemphigoid (BP), an autoimmune blistering disease induced by autoantibodies against type XVII collagen (COL17); however, this theory does not fully explain the pathological features of BP. Recently, the involvement of complement-independent pathways has been proposed. To directly address the question of the necessity of the complement activation in blister formation, we generated C3-deficient COL17-humanized mice. First, we show that passive transfer of autoantibodies from BP patients induced blister formation in neonatal C3-deficient COL17-humanized mice without complement activation. By using newly generated human and murine mAbs against the pathogenic noncollagenous 16A domain of COL17 with high (human IgG1, murine IgG2), low (murine IgG1), or no (human IgG4) complement activation abilities, we demonstrate that the deposition of Abs, and not complements, is relevant to the induction of blister formation in neonatal and adult mice. Notably, passive transfer of BP autoantibodies reduced the amount of COL17 in lesional mice skin, as observed in cultured normal human keratinocytes treated with the same Abs. Moreover, the COL17 depletion was associated with a ubiquitin/proteasome pathway. In conclusion, the COL17 depletion induced by BP autoantibodies, and not complement activation, is essential for the blister formation under our experimental system. Copyright © 2014 by The American Association of Immunologists, Inc.

  19. SALSA: a regulator of the early steps of complement activation on mucosal surfaces

    Directory of Open Access Journals (Sweden)

    Martin eReichhardt

    2016-03-01

    Full Text Available Complement is present mainly in blood. However, following mechanical damage or inflammation, serous exudates enter the mucosal surfaces. Here the complement proteins interact with other endogenous molecules to keep microbes from entering the parenteral tissues. One of the mucosal proteins known to interact with the early complement components of both the classical and the lectin pathway, is the salivary scavenger and agglutinin (SALSA. SALSA is also known as DMBT1 (deleted in malignant brain tumors 1 and gp340. It is found both attached to the epithelium and secreted into the surrounding fluids of most mucosal surfaces. SALSA has been shown to bind directly to C1q, mannose binding lectin (MBL and the ficolins. Through these interactions SALSA regulates activation of the complement system. In addition, SALSA interacts with surfactant proteins A and D, secretory IgA and lactoferrin. Ulcerative colitis and Crohn’s disease are examples of diseases, where complement activation in mucosal tissues may occur. This review describes the latest advances in our understanding of how the early complement components interact with the SALSA molecule. Furthermore, we discuss how these interactions may affect disease propagation on mucosal surfaces in immunological and inflammatory diseases.

  20. Hemolytic plate assay for quantification of active human complement component C3 using methylamine-treated plasma as complement source

    DEFF Research Database (Denmark)

    Ploug, M; Jessen, T E; Welinder, K. G.

    1985-01-01

    A hemolytic plate assay specific for active human complement component C3 is described. The method is well suited for tracing active C3 during preparative purification or for screening of plasma samples. The assay is based on activation of the alternative pathway of complement by unmodified rabbi...

  1. Complement-coagulation cross-talk: a potential mediator of the physiological activation of complement by low pH

    Directory of Open Access Journals (Sweden)

    Hany Ibrahim Kenawy

    2015-05-01

    Full Text Available The complement system is a major constituent of the innate immune system. It not only bridges innate and adaptive arms of the immune system but also links the immune system with the coagulation system. Current understanding of the role of complement has extended far beyond fighting of infections, and now encompasses maintenance of homeostasis, tissue regeneration and pathophysiology of multiple diseases. It has been known for many years that complement activation is strongly pH sensitive, but only relatively recently has the physiological significance of this been appreciated. Most complement assays are carried out at the physiological pH 7.4. However, pH in some extracellular compartments, for example renal tubular fluid in parts of the tubule, and extracellular fluid at inflammation loci, is sufficiently acidic to activate complement. The exact molecular mechanism of this activation is still unclear, but possible cross talk between the contact system and complement may exist at low pH with subsequent complement activation. The current article reviews the published data on the effect of pH on the contact system and complement activity, the nature of the pH sensor molecules, and the clinical implications of these effects. Of particular interest is chronic kidney disease (CKD accompanied by metabolic acidosis, in which therapeutic alkalinisation of urine has been shown significantly to reduce tubular complement activation products, an effect which may have important implications for slowing progression of CKD.

  2. Complement-Coagulation Cross-Talk: A Potential Mediator of the Physiological Activation of Complement by Low pH.

    Science.gov (United States)

    Kenawy, Hany Ibrahim; Boral, Ismet; Bevington, Alan

    2015-01-01

    The complement system is a major constituent of the innate immune system. It not only bridges innate and adaptive arms of the immune system but also links the immune system with the coagulation system. Current understanding of the role of complement has extended far beyond fighting of infections, and now encompasses maintenance of homeostasis, tissue regeneration, and pathophysiology of multiple diseases. It has been known for many years that complement activation is strongly pH sensitive, but only relatively recently has the physiological significance of this been appreciated. Most complement assays are carried out at the physiological pH 7.4. However, pH in some extracellular compartments, for example, renal tubular fluid in parts of the tubule, and extracellular fluid at inflammation loci, is sufficiently acidic to activate complement. The exact molecular mechanism of this activation is still unclear, but possible cross-talk between the contact system (intrinsic pathway) and complement may exist at low pH with subsequent complement activation. The current article reviews the published data on the effect of pH on the contact system and complement activity, the nature of the pH sensor molecules, and the clinical implications of these effects. Of particular interest is chronic kidney disease (CKD) accompanied by metabolic acidosis, in which therapeutic alkalinization of urine has been shown significantly to reduce tubular complement activation products, an effect, which may have important implications for slowing progression of CKD.

  3. The Structure-Activity Relationship between Marine Algae Polysaccharides and Anti-Complement Activity.

    Science.gov (United States)

    Jin, Weihua; Zhang, Wenjing; Liang, Hongze; Zhang, Quanbin

    2015-12-25

    In this study, 33 different polysaccharides were prepared to investigate the structure-activity relationships between the polysaccharides, mainly from marine algae, and anti-complement activity in the classical pathway. Factors considered included extraction methods, fractionations, molecular weight, molar ratio of galactose to fucose, sulfate, uronic acid (UA) content, linkage, branching, and the type of monosaccharide. It was shown that the larger the molecular weights, the better the activities. The molar ratio of galactose (Gal) to fucose (Fuc) was a positive factor at a concentration lower than 10 µg/mL, while it had no effect at a concentration more than 10 µg/mL. In addition, sulfate was necessary; however, the sulfate content, the sulfate pattern, linkage and branching had no effect at a concentration of more than 10 µg/mL. Moreover, the type of monosaccharide had no effect. Laminaran and UA fractions had no activity; however, they could reduce the activity by decreasing the effective concentration of the active composition when they were mixed with the active compositions. The effect of the extraction methods could not be determined. Finally, it was observed that sulfated galactofucan showed good anti-complement activity after separation.

  4. Complement and contact activation in term neonates after fetal acidosis

    Science.gov (United States)

    Sonntag, J.; Wagner, M.; Strauss, E.; Obladen, M.

    1998-01-01

    AIMS—To evaluate complement and contact activation after fetal acidosis.
METHODS—Fifteen term neonates with hypoxic-ischaemic encephalopathy after umbilical arterial pH 7.20. Determinations of the complement function and C1-inhibitor activity were performed as kinetic tests 22-28 hours after birth. C1q, C1-inhibitor, and factor B concentrations were determined by radial immunodiffusion and those of C3a, C5a, and factor XIIa by enzyme immunoabsorbent assay.
RESULTS—Median complement function (46 vs 73 %), C1q (4.3 vs 9.1 mg/dl), and factor B (5.2 vs 7.7 mg/dl) decreased after fetal acidosis. The activated split products C3a (260 vs 185 µg/l), C5a (5.0 vs 0.6 µg/l), and factor XIIa (3.2 vs 1.3 µg/l) increased in the neonates after fetal acidosis. No differences were found in the concentration and activity of C1-inhibitor.
CONCLUSIONS—Complement and contact activation occurred in the newborns with hypoxic-ischaemic encephalopathy. Activation of these systems generates mediators which can trigger inflammation and tissue injury.

 PMID:9577283

  5. Complement activation in leprosy: a retrospective study shows elevated circulating terminal complement complex in reactional leprosy.

    Science.gov (United States)

    Bahia El Idrissi, N; Hakobyan, S; Ramaglia, V; Geluk, A; Morgan, B Paul; Das, P Kumar; Baas, F

    2016-06-01

    Mycobacterium leprae infection gives rise to the immunologically and histopathologically classified spectrum of leprosy. At present, several tools for the stratification of patients are based on acquired immunity markers. However, the role of innate immunity, particularly the complement system, is largely unexplored. The present retrospective study was undertaken to explore whether the systemic levels of complement activation components and regulators can stratify leprosy patients, particularly in reference to the reactional state of the disease. Serum samples from two cohorts were analysed. The cohort from Bangladesh included multi-bacillary (MB) patients with (n = 12) or without (n = 46) reaction (R) at intake and endemic controls (n = 20). The cohort from Ethiopia included pauci-bacillary (PB) (n = 7) and MB (n = 23) patients without reaction and MB (n = 15) patients with reaction. The results showed that the activation products terminal complement complex (TCC) (P ≤ 0·01), C4d (P ≤ 0·05) and iC3b (P ≤ 0·05) were specifically elevated in Bangladeshi patients with reaction at intake compared to endemic controls. In addition, levels of the regulator clusterin (P ≤ 0·001 without R; P < 0·05 with R) were also elevated in MB patients, irrespective of a reaction. Similar analysis of the Ethiopian cohort confirmed that, irrespective of a reaction, serum TCC levels were increased significantly in patients with reactions compared to patients without reactions (P ≤ 0·05). Our findings suggests that serum TCC levels may prove to be a valuable tool in diagnosing patients at risk of developing reactions. © 2016 British Society for Immunology.

  6. Complement activation in Ghanaian children with severe Plasmodium falciparum malaria

    Directory of Open Access Journals (Sweden)

    Ofori Michael F

    2007-12-01

    Full Text Available Abstract Background Severe anaemia (SA, intravascular haemolysis (IVH and respiratory distress (RD are severe forms of Plasmodium falciparum malaria, with RD reported to be of prognostic importance in African children with malarial anaemia. Complement factors have been implicated in the mechanism leading to excess anaemia in acute P. falciparum infection. Methods The direct Coombs test (DCT and flow cytometry were used to investigate the mean levels of RBC-bound complement fragments (C3d and C3bαβ and the regulatory proteins [complement receptor 1 (CD35 and decay accelerating factor (CD55] in children with discrete clinical forms of P. falciparum malaria. The relationship between the findings and clinical parameters including coma, haemoglobin (Hb levels and RD were investigated. Results Of the 484 samples tested, 131(27% were positive in DCT, out of which 115/131 (87.8% were positive for C3d alone while 16/131 (12.2% were positive for either IgG alone or both. 67.4% of the study population were below 5 years of age and DCT positivity was more common in this age group relative to children who were 5 years or older (Odds ratio, OR = 3.8; 95%CI, 2.2–6.7, p Conclusion These results suggest that complement activation contributed to anaemia in acute childhood P. falciparum malaria, possibly through induction of erythrophagocytosis and haemolysis. In contrast to other studies, this study did not find association between levels of the complement regulatory proteins, CD35 and CD55 and malarial anaemia. These findings suggest that complement activation could also be involved in the pathogenesis of RD but larger studies are needed to confirm this finding.

  7. Shiga toxin activates complement and binds factor H: evidence for an active role of complement in hemolytic uremic syndrome.

    Science.gov (United States)

    Orth, Dorothea; Khan, Abdul Basit; Naim, Asma; Grif, Katharina; Brockmeyer, Jens; Karch, Helge; Joannidis, Michael; Clark, Simon J; Day, Anthony J; Fidanzi, Sonja; Stoiber, Heribert; Dierich, Manfred P; Zimmerhackl, Lothar B; Würzner, Reinhard

    2009-05-15

    Infections with enterohemorrhagic Escherichia coli (EHEC) are a major cause of hemolytic uremic syndrome (HUS). Shiga toxins (Stxs), especially Stx2, are believed to represent major virulence factors of EHEC, contributing to HUS pathogenesis. Beside EHEC-associated HUS, there are hereditary atypical forms of HUS, which are mostly caused by mutations of complement regulators. The aim of the present study was to investigate whether or not complement is also involved in the pathogenesis of EHEC-induced typical HUS, by being activated either directly or indirectly by involvement of its inhibitors. Purified Stx2 markedly activated complement via the alternative pathway and was found to bind to factor H (FH), however, only when it was active. No apparent cleavage or destruction of FH was visible, and cofactor activity in fluid phase was unaffected, but clearly delayed for surface-attached FH, where it is essential for host cell protection. Binding studies using FH constructs revealed that Stx2 binds to short consensus repeats (SCRs) 6-8 and SCRs18-20, but not to SCRs16-17, i.e., to regions involved in the surface recognition function of FH. In conclusion, complement, and in particular FH, not only plays an important role in atypical HUS, but most probably also in EHEC-induced HUS.

  8. Synergy between the classical and alternative pathways of complement is essential for conferring effective protection against the pandemic influenza A(H1N1) 2009 virus infection

    Science.gov (United States)

    Rattan, Ajitanuj; Pawar, Shailesh D.; Nawadkar, Renuka; Kulkarni, Neeraja

    2017-01-01

    The pandemic influenza A(H1N1) 2009 virus caused significant morbidity and mortality worldwide thus necessitating the need to understand the host factors that influence its control. Previously, the complement system has been shown to provide protection during the seasonal influenza virus infection, however, the role of individual complement pathways is not yet clear. Here, we have dissected the role of intact complement as well as of its individual activation pathways during the pandemic influenza virus infection using mouse strains deficient in various complement components. We show that the virus infection in C3-/- mice results in increased viral load and 100% mortality, which can be reversed by adoptive transfer of naïve wild-type (WT) splenocytes, purified splenic B cells, or passive transfer of immune sera from WT, but not C3-/- mice. Blocking of C3a and/or C5a receptor signaling in WT mice using receptor antagonists and use of C3aR-/- and C5aR-/- mice showed significant mortality after blocking/ablation of C3aR, with little or no effect after blocking/ablation of C5aR. Intriguingly, deficiency of C4 and FB in mice resulted in only partial mortality (24%-32%) suggesting a necessary cross-talk between the classical/lectin and alternative pathways for providing effective protection. In vitro virus neutralization experiments performed to probe the cross-talk between the various pathways indicated that activation of the classical and alternative pathways in concert, owing to coating of viral surface by antibodies, is needed for its efficient neutralization. Examination of the virus-specific complement-binding antibodies in virus positive subjects showed that their levels vary among individuals. Together these results indicate that cooperation between the classical and alternative pathways not only result in efficient direct neutralization of the pandemic influenza virus, but also lead to the optimum generation of C3a, which when sensed by the immune cells along

  9. Assembly and activation of alternative complement components on endothelial cell-anchored ultra-large von Willebrand factor links complement and hemostasis-thrombosis.

    Directory of Open Access Journals (Sweden)

    Nancy A Turner

    Full Text Available BACKGROUND: Vascular endothelial cells (ECs express and release protein components of the complement pathways, as well as secreting and anchoring ultra-large von Willebrand factor (ULVWF multimers in long string-like structures that initiate platelet adhesion during hemostasis and thrombosis. The alternative complement pathway (AP is an important non-antibody-requiring host defense system. Thrombotic microangiopathies can be associated with defective regulation of the AP (atypical hemolytic-uremic syndrome or with inadequate cleavage by ADAMTS-13 of ULVWF multimeric strings secreted by/anchored to ECs (thrombotic thrombocytopenic purpura. Our goal was to determine if EC-anchored ULVWF strings caused the assembly and activation of AP components, thereby linking two essential defense mechanisms. METHODOLOGY/PRINCIPAL FINDINGS: We quantified gene expression of these complement components in cultured human umbilical vein endothelial cells (HUVECs by real-time PCR: C3 and C5; complement factor (CF B, CFD, CFP, CFH and CFI of the AP; and C4 of the classical and lectin (but not alternative complement pathways. We used fluorescent microscopy, monospecific antibodies against complement components, fluorescent secondary antibodies, and the analysis of >150 images to quantify the attachment of HUVEC-released complement proteins to ULVWF strings secreted by, and anchored to, the HUVECs (under conditions of ADAMTS-13 inhibition. We found that HUVEC-released C4 did not attach to ULVWF strings, ruling out activation of the classical and lectin pathways by the strings. In contrast, C3, FB, FD, FP and C5, FH and FI attached to ULVWF strings in quantitative patterns consistent with assembly of the AP components into active complexes. This was verified when non-functional FB blocked the formation of AP C3 convertase complexes (C3bBb on ULVWF strings. CONCLUSIONS/SIGNIFICANCE: AP components are assembled and activated on EC-secreted/anchored ULVWF multimeric

  10. Klein-Gordon Transformation sans Extraneous Insertions: the Isomorphic Classical Complement to a Quantum System

    CERN Document Server

    Kauffmann, Steven Kenneth

    2013-01-01

    The historical Klein-Gordon transformation of complex-valued first-order in time Schroedinger equations iterates these in a naively straightforward way which changes them into complex-valued second-order in time equations that have a plethora of extraneous solutions -- the transformation is an operator-calculus analogue of the squaring of both sides of an algebraic equation. The real and imaginary parts of a Schroedinger equation, however, are well known to be precisely the dynamical equation pair of the real-valued classical Hamiltonian functional which is numerically equal to the expectation value of that Schroedinger equation's Hermitian Hamiltonian operator. The purely real-valued second-order in time Euler-Lagrange equation of the corresponding classical Lagrangian functional is also isomorphic to that Schroedinger equation, and for symmetric Hamiltonians has exactly the same formal appearance as the corresponding naive complex-valued Klein-Gordon equation, but none of the latter's extraneous solutions. ...

  11. Up-regulated production and activation of the complement system in Alzheimer's disease brain.

    Science.gov (United States)

    Yasojima, K; Schwab, C; McGeer, E G; McGeer, P L

    1999-03-01

    We used reverse transcriptase-polymerase chain reaction and Western blotting techniques to measure the levels of complement mRNAs and their protein products in Alzheimer's disease (AD) brain compared with non-AD brain. mRNAs for C1q, C1r, C1s, C2, C3, C4, C5, C6, C7, C8, and C9 were detected in the 11 regions of brain that were investigated. The mRNA levels were markedly up-regulated in affected areas of AD brain. In the entorhinal cortex, hippocampus, and midtemporal gyrus, which had dense accumulations of plaques and tangles, C1q mRNA was increased 11- to 80-fold over control levels, and C9 mRNA 10- to 27-fold. These levels were substantially higher than in the livers of the same cases. Western blot analysis of AD hippocampus established the presence of all of the native complement proteins as well as their activation products C4d, C3d, and the membrane attack complex. These data indicate that high levels of complement are being produced in affected areas of AD brain, that full activation of the classical complement pathway is continuously taking place, and that this activation may be contributing significantly to AD pathology.

  12. Contribution of complement activation pathways to neuropathology differs among mouse models of Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Kimura Yuko

    2011-01-01

    Full Text Available Abstract Background Complement proteins and activation products have been found associated with neuropathology in Alzheimer's disease (AD. Recently, a C5a receptor antagonist was shown to suppress neuropathology in two murine models of AD, Tg2576 and 3xTg. Previously, a genetic deficiency of C1q in the Tg2576 mouse model showed an accumulation of fibrillar plaques similar to the complement sufficient Tg2576, but reactive glia were significantly decreased and neuronal integrity was improved suggesting detrimental consequences for complement activation in AD. The goal of this study was to define the role of the classical complement activation pathway in the progression of pathology in the 3xTg mouse that develops tangles in addition to fibrillar plaques (more closely reflecting human AD pathology and to assess the influence of complement in a model of AD with a higher level of complement hemolytic activity. Methods 3xTg mice deficient in C1q (3xTgQ-/- were generated, and both 3xTg and 3xTgQ-/- were backcrossed to the BUB mouse strain which has higher in vitro hemolytic complement activity. Mice were aged and perfused, and brain sections stained for pathological markers or analyzed for proinflammatory marker expression. Results 3xTgQ-/- mice showed similar amounts of fibrillar amyloid, reactive glia and hyperphosphorylated tau as the C1q-sufficient 3xTg at the ages analyzed. However, 3xTg and 3xTgQ-/- on the BUB background developed pathology earlier than on the original 3xTg background, although the presence of C1q had no effect on neuropathological and pro-inflammatory markers. In contrast to that seen in other transgenic models of AD, C1q, C4 and C3 immunoreactivity was undetectable on the plaques of 3xTg in any background, although C3 was associated with reactive astrocytes surrounding the plaques. Importantly, properdin a component of the alternative complement pathway was associated with plaques in all models. Conclusions In contrast to

  13. Systemic complement activation, lung injury, and products of lipid peroxidation.

    OpenAIRE

    Ward, P. A.; Till, G O; Hatherill, J. R.; Annesley, T M; Kunkel, R G

    1985-01-01

    Previously we have demonstrated that systemic activation of the complement system after intravenous injection of cobra venom factor (CVF) results in acute lung injury as reflected by increases in the vascular permeability of the lung as well as by morphologic evidence of damage to lung vascular endothelial cells. In using the vascular permeability of the lung as the reference, the current studies show a quantitative correlation between lung injury and the appearance in plasma of lipid peroxid...

  14. The relative merits of therapies being developed to tackle inappropriate (‘self’-directed) complement activation

    OpenAIRE

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

    2016-01-01

    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 contribut...

  15. Early Intra-Articular Complement Activation in Ankle Fractures

    Directory of Open Access Journals (Sweden)

    Hagen Schmal

    2014-01-01

    Full Text Available Cytokine regulation possibly influences long term outcome following ankle fractures, but little is known about synovial fracture biochemistry. Eight patients with an ankle dislocation fracture were included in a prospective case series and matched with patients suffering from grade 2 osteochondritis dissecans (OCD of the ankle. All fractures needed external fixation during which joint effusions were collected. Fluid analysis was done by ELISA measuring aggrecan, bFGF, IL-1β, IGF-1, and the complement components C3a, C5a, and C5b-9. The time periods between occurrence of fracture and collection of effusion were only significantly associated with synovial aggrecan and C5b-9 levels (P<0.001. Furthermore, synovial expressions of both proteins correlated with each other (P<0.001. Although IL-1β expression was relatively low, intra-articular levels correlated with C5a (P<0.01 and serological C-reactive protein concentrations 2 days after surgery (P<0.05. Joint effusions were initially dominated by neutrophils, but the portion of monocytes constantly increased reaching 50% at day 6 after fracture (P<0.02. Whereas aggrecan and IL-1β concentrations were not different in fracture and OCD patients, bFGF, IGF-1, and all complement components were significantly higher concentrated in ankle joints with fractures (P<0.01. Complement activation and inflammatory cell infiltration characterize the joint biology following acute ankle fractures.

  16. A Small Group Activity About Bacterial Regulation And Complementation

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    Susan M. Merkel

    2010-11-01

    Full Text Available As teachers, we well understand the need for activities that help develop critical-thinking skills in microbiology. In our experience, one concept that students have difficulty understanding is transcriptional regulation of bacterial genes. To help with this, we developed and evaluated a paper-based activity to help students understand and apply the concepts of bacterial transcriptional regulation. While we don't identify it as such, we use a complementation experiment to assess student understanding of how regulation changes when new DNA is introduced. In Part 1 of this activity, students complete an open book, take-home assignment that asks them to define common terminology related to regulation, and draw the regulatory components of different scenarios involving positive and negative regulation. In Part 2, students work in small groups of 3-4 to depict the regulatory components for a different scenario. They are asked to explain the results of a complementation experiment based on this scenario. They then predict the results of a slightly different experiment. Students who completed the Regulation Activity did significantly better on post-test questions related to regulation, compared to pre-test questions.

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

    Energy Technology Data Exchange (ETDEWEB)

    van Rensburg, C.E.J.; Naude, P.J. [University of Pretoria, Pretoria (South Africa)

    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.

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

    Science.gov (United States)

    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.

  19. Trypanosoma cruzi calreticulin inhibits the complement lectin pathway activation by direct interaction with L-Ficolin.

    Science.gov (United States)

    Sosoniuk, Eduardo; Vallejos, Gerardo; Kenawy, Hany; Gaboriaud, Christine; Thielens, Nicole; Fujita, Teizo; Schwaeble, Wilhelm; Ferreira, Arturo; Valck, Carolina

    2014-07-01

    Trypanosoma cruzi, the agent of Chagas' disease, the sixth neglected tropical disease worldwide, infects 10-12 million people in Latin America. Differently from T. cruzi epimastigotes, trypomastigotes are complement-resistant and infective. CRPs, T-DAF, sialic acid and lipases explain at least part of this resistance. In vitro, T. cruzi calreticulin (TcCRT), a chaperone molecule that translocates from the ER to the parasite surface: (a) Inhibits the human classical complement activation, by interacting with C1, (b) As a consequence, an increase in infectivity is evident and, (c) It inhibits angiogenesis and tumor growth. We report here that TcCRT also binds to the L-Ficolin collagenous portion, thus inhibiting approximately between 35 and 64% of the human complement lectin pathway activation, initiated by L-Ficolin, a property not shared by H-Ficolin. While L-Ficolin binds to 60% of trypomastigotes and to 24% of epimastigotes, 50% of the former and 4% of the latter display TcCRT on their surfaces. Altogether, these data indicate that TcCRT is a parasite inhibitory receptor for Ficolins. The resulting evasive activities, together with the TcCRT capacity to inhibit C1, with a concomitant increase in infectivity, may represent T. cruzi strategies to inhibit important arms of the innate immune response.

  20. Circulating AIM Prevents Hepatocellular Carcinoma through Complement Activation

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    Natsumi Maehara

    2014-10-01

    Full Text Available Hepatocellular carcinoma (HCC is a widespread fatal disease and the third most common cause of cancer deaths. Here, we show the potent anti-HCC effect of the circulating protein AIM. As in adipocytes, AIM is incorporated into normal hepatocytes, where it interferes with lipid storage. In contrast, AIM accumulates on the HCC cell surface and activates the complement cascade via inactivating multiple regulators of complement activation. This response provokes necrotic cell death specifically in AIM-bound HCC cells. Accordingly, AIM−/− mice were highly susceptible to steatosis-associated HCC development, whereas no AIM+/+ mouse developed the disease despite comparable liver inflammation and fibrosis in response to a long-term high-fat diet. Administration of AIM prevented tumor development in AIM−/− mice, and HCC induction by diethylnitrosamine was more prominent in AIM−/− than wild-type mice. These findings could be the basis for novel AIM-based therapeutic strategies for HCC.

  1. Inhibition of complement activation by natural sulfated polysaccharides (fucans) from brown seaweed.

    Science.gov (United States)

    Blondin, C; Fischer, E; Boisson-Vidal, C; Kazatchkine, M D; Jozefonvicz, J

    1994-03-01

    In the present study, we demonstrate that natural sulfated polysaccharides (fucans) isolated from brown seaweed are potent inhibitors of human complement activation. A fucan fraction of chromatographic molecular weight 22,600, termed BS8, was found to inhibit classical and alternative pathway activation in whole serum in a dose-dependent fashion. Fucan BS8 inhibited formation of the classical pathway C3 convertase by interfering with C1 activation or by inhibiting C4 cleavage and the interaction between C4b and C2. The fucan also inhibited formation/function of the alternative pathway C3 convertase by suppressing the binding of B to C3b and by interfering with the stabilizing function of Properdin. The inhibitory effect of fucans on formation of the C3 convertases was dependent on the molecular weight of the polysaccharide for compounds of chromatographic molecular weight below 16,600. Fucan had no effect on the function of the terminal complex. Since fucans were more efficient than heparin in inhibiting activation of the classical pathway in whole serum and exhibited a lesser specific anticoagulant activity on a molar basis, our results suggest that these natural sulfated polysaccharides have a potential for use as anti-complementary and anti-inflammatory agents.

  2. Complement alternative pathway activation in human nonalcoholic steatohepatitis.

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    Filip M Segers

    Full Text Available The innate immune system plays a major role in the pathogenesis of nonalcoholic steatohepatitis (NASH. Recently we reported complement activation in human NASH. However, it remained unclear whether the alternative pathway of complement, which amplifies C3 activation and which is frequently associated with pathological complement activation leading to disease, was involved. Here, alternative pathway components were investigated in liver biopsies of obese subjects with healthy livers (n = 10 or with NASH (n = 12 using quantitative PCR, Western blotting, and immunofluorescence staining. Properdin accumulated in areas where neutrophils surrounded steatotic hepatocytes, and colocalized with the C3 activation product C3c. C3 activation status as expressed by the C3c/native C3 ratio was 2.6-fold higher (p<0.01 in subjects with NASH despite reduced native C3 concentrations (0.94±0.12 vs. 0.57±0.09; p<0.01. Hepatic properdin levels positively correlated with levels of C3c (rs = 0.69; p<0.05 and C3c/C3 activation ratio (rs = 0.59; p<0.05. C3c, C3 activation status (C3c/C3 ratio and properdin levels increased with higher lobular inflammation scores as determined according to the Kleiner classification (C3c: p<0.01, C3c/C3 ratio: p<0.05, properdin: p<0.05. Hepatic mRNA expression of factor B and factor D did not differ between subjects with healthy livers and subjects with NASH (factor B: 1.00±0.19 vs. 0.71±0.07, p = 0.26; factor D: 1.00±0.21 vs. 0.66±0.14, p = 0.29;. Hepatic mRNA and protein levels of Decay Accelerating Factor tended to be increased in subjects with NASH (mRNA: 1.00±0.14 vs. 2.37±0.72; p = 0.22; protein: 0.51±0.11 vs. 1.97±0.67; p = 0.28. In contrast, factor H mRNA was downregulated in patients with NASH (1.00±0.09 vs. 0.71±0.06; p<0.05 and a similar trend was observed with hepatic protein levels (1.12±0.16 vs. 0.78±0.07; p = 0.08. Collectively, these data suggest a role for alternative

  3. The extracellular adherence protein from Staphylococcus aureus inhibits the classical and lectin pathways of complement by blocking formation of the C3 proconvertase.

    Science.gov (United States)

    Woehl, Jordan L; Stapels, Daphne A C; Garcia, Brandon L; Ramyar, Kasra X; Keightley, Andrew; Ruyken, Maartje; Syriga, Maria; Sfyroera, Georgia; Weber, Alexander B; Zolkiewski, Michal; Ricklin, Daniel; Lambris, John D; Rooijakkers, Suzan H M; Geisbrecht, Brian V

    2014-12-15

    The pathogenic bacterium Staphylococcus aureus actively evades many aspects of human innate immunity by expressing a series of small inhibitory proteins. A number of these proteins inhibit the complement system, which labels bacteria for phagocytosis and generates inflammatory chemoattractants. Although the majority of staphylococcal complement inhibitors act on the alternative pathway to block the amplification loop, only a few proteins act on the initial recognition cascades that constitute the classical pathway (CP) and lectin pathway (LP). We screened a collection of recombinant, secreted staphylococcal proteins to determine whether S. aureus produces other molecules that inhibit the CP and/or LP. Using this approach, we identified the extracellular adherence protein (Eap) as a potent, specific inhibitor of both the CP and LP. We found that Eap blocked CP/LP-dependent activation of C3, but not C4, and that Eap likewise inhibited deposition of C3b on the surface of S. aureus cells. In turn, this significantly diminished the extent of S. aureus opsonophagocytosis and killing by neutrophils. This combination of functional properties suggested that Eap acts specifically at the level of the CP/LP C3 convertase (C4b2a). Indeed, we demonstrated a direct, nanomolar-affinity interaction of Eap with C4b. Eap binding to C4b inhibited binding of both full-length C2 and its C2b fragment, which indicated that Eap disrupts formation of the CP/LP C3 proconvertase (C4b2). As a whole, our results demonstrate that S. aureus inhibits two initiation routes of complement by expression of the Eap protein, and thereby define a novel mechanism of immune evasion.

  4. Complement factor B activation in patients with preeclampsia.

    Science.gov (United States)

    Velickovic, Ivan; Dalloul, Mudar; Wong, Karen A; Bakare, Olufunke; Schweis, Franz; Garala, Maya; Alam, Amit; Medranda, Giorgio; Lekovic, Jovana; Shuaib, Waqas; Tedjasukmana, Andreas; Little, Perry; Hanono, Daniel; Wijetilaka, Ruvini; Weedon, Jeremy; Lin, Jun; Toledano, Roulhac d'Arby; Zhang, Ming

    2015-06-01

    Preeclampsia is a leading cause of maternal and fetal morbidity and mortality. Bb, the active fragment of complement factor B (fB), has been reported to be a predictor of preeclampsia. However, conflicting results have been found by some investigators. We hypothesized that the disagreement in findings may be due to the racial/ethnic differences among various study groups, and that fB activation is significant in women of an ethnic minority with preeclampsia. We investigated the maternal and fetal levels of Bb (the activated fB fragment) in pregnant women of an ethnic minority with or without preeclampsia. We enrolled 291 pregnant women (96% of an ethnic minority, including 78% African-American). Thirteen percent of these were diagnosed with preeclampsia. Maternal venous blood was collected from all participants together with fetal umbilical cord blood samples from 154 deliveries in the 291 women. The results were analyzed using the Mann-Whitney U test and multivariate analyses. Maternal Bb levels were significantly higher in the preeclamptic group than in the nonpreeclamptic group. Levels of Bb in fetal cord blood were similar in both groups. Subgroup analyses of African-American patients' results confirmed the study hypothesis that there would be a significant increase in Bb in the maternal blood of the preeclamptic group and no increase in Bb in the fetal cord blood of this group. These results suggest that a maternal immune response through complement fB might play a role in the development of preeclampsia, particularly in African-American patients. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  5. Alternative Pathway Dysregulation and the Conundrum of Complement Activation by IgG4 Immune Complexes in Membranous Nephropathy

    Science.gov (United States)

    Borza, Dorin-Bogdan

    2016-01-01

    Membranous nephropathy (MN), a major cause of nephrotic syndrome, is a non-inflammatory immune kidney disease mediated by IgG antibodies that form glomerular subepithelial immune complexes. In primary MN, autoantibodies target proteins expressed on the podocyte surface, often phospholipase A2 receptor (PLA2R1). Pathology is driven by complement activation, leading to podocyte injury and proteinuria. This article overviews the mechanisms of complement activation and regulation in MN, addressing the paradox that anti-PLA2R1 and other antibodies causing primary MN are predominantly (but not exclusively) IgG4, an IgG subclass that does not fix complement. Besides immune complexes, alterations of the glomerular basement membrane (GBM) in MN may lead to impaired regulation of the alternative pathway (AP). The AP amplifies complement activation on surfaces insufficiently protected by complement regulatory proteins. Whereas podocytes are protected by cell-bound regulators, the GBM must recruit plasma factor H, which inhibits the AP on host surfaces carrying certain polyanions, such as heparan sulfate (HS) chains. Because HS chains present in the normal GBM are lost in MN, we posit that the local complement regulation by factor H may be impaired as a result. Thus, the loss of GBM HS in MN creates a micro-environment that promotes local amplification of complement activation, which in turn may be initiated via the classical or lectin pathways by subsets of IgG in immune complexes. A detailed understanding of the mechanisms of complement activation and dysregulation in MN is important for designing more effective therapies. PMID:27199983

  6. Complement receptor expression and activation of the complement cascade on B lymphocytes from patients with systemic lupus erythematosus (SLE)

    DEFF Research Database (Denmark)

    Marquart, H V; Svendsen, Anders Jørgen; Rasmussen, J M

    1995-01-01

    It has previously been reported that the expression of the complement receptors, CR1 on erythrocytes and blood leucocytes and CR2 on B cells, is reduced in patients with SLE, and that the reduced expression of CR1 on erythrocytes is related to disease activity. We have earlier demonstrated that n...

  7. Complement receptor expression and activation of the complement cascade on B lymphocytes from patients with systemic lupus erythematosus (SLE)

    DEFF Research Database (Denmark)

    Marquart, H V; Svendsen, A; Rasmussen, J M

    1995-01-01

    It has previously been reported that the expression of the complement receptors, CR1 on erythrocytes and blood leucocytes and CR2 on B cells, is reduced in patients with SLE, and that the reduced expression of CR1 on erythrocytes is related to disease activity. We have earlier demonstrated that n...

  8. Complement component C3 and butyrylcholinesterase activity are associated with neurodegeneration and clinical disability in multiple sclerosis.

    Directory of Open Access Journals (Sweden)

    Shahin Aeinehband

    Full Text Available Dysregulation of the complement system is evident in many CNS diseases but mechanisms regulating complement activation in the CNS remain unclear. In a recent large rat genome-wide expression profiling and linkage analysis we found co-regulation of complement C3 immediately downstream of butyrylcholinesterase (BuChE, an enzyme hydrolyzing acetylcholine (ACh, a classical neurotransmitter with immunoregulatory effects. We here determined levels of neurofilament-light (NFL, a marker for ongoing nerve injury, C3 and activity of the two main ACh hydrolyzing enzymes, acetylcholinesterase (AChE and BuChE, in cerebrospinal fluid (CSF from patients with MS (n = 48 and non-inflammatory controls (n = 18. C3 levels were elevated in MS patients compared to controls and correlated both to disability and NFL. C3 levels were not induced by relapses, but were increased in patients with ≥9 cerebral lesions on magnetic resonance imaging and in patients with progressive disease. BuChE activity did not differ at the group level, but was correlated to both C3 and NFL levels in individual samples. In conclusion, we show that CSF C3 correlates both to a marker for ongoing nerve injury and degree of disease disability. Moreover, our results also suggest a potential link between intrathecal cholinergic activity and complement activation. These results motivate further efforts directed at elucidating the regulation and effector functions of the complement system in MS, and its relation to cholinergic tone.

  9. Complement activation in plasma before and after infliximab treatment in Crohn disease

    DEFF Research Database (Denmark)

    Zimmermann-Nielsen, E; Agnholt, J; Thorlacius-Ussing, O

    2003-01-01

    BACKGROUND: Crohn disease is characterized by up-regulated intestinal inflammation mainly caused by increased tumour necrosis factor alpha (TNF-alpha) levels. However, the complement system (C) may also have a role in maintaining inflammation. METHODS: Plasma from 26 patients with Crohn disease...... complicated by fistulizing ano-rectal disease was collected before and after three Infliximab infusions (5 mg kg(-1)). RESULTS: Before treatment, the C3-activation capacities (C3-AC) in plasma from patients with Crohn disease were comparable with values obtained from healthy controls. The classical C pathway......-mediated C3-AC, mannan-binding lectin C4-AC, leucocyte count, C-reactive protein concentration and Crohn Disease Activity Index decreased significantly 8 weeks after the first infusion of Infliximab (P

  10. A novel anti-inflammatory activity of lysozyme: modulation of serum complement activation

    Directory of Open Access Journals (Sweden)

    M. O. Ogundele

    1998-01-01

    Full Text Available Lysozyme is an ubiquitous enzyme found in most biological secretions and leukocytes. This study was aimed at investigating its interaction with other inflammatory mediators on mucosa surfaces, particularly the complement system. Lysozyme has been shown in our present study, to inhibit the haemolytic activity of serum complement in a dose-dependent fashion, when tested within the levels present in normal and inflamed breast-milk samples, and other mucosal secretions. This represents a new antiinflammatory action of lysozym e in relation to the serum complement, and the exact mode of the interaction need further studies.

  11. Complement in autoimmune diseases.

    Science.gov (United States)

    Vignesh, Pandiarajan; Rawat, Amit; Sharma, Madhubala; Singh, Surjit

    2017-02-01

    The complement system is an ancient and evolutionary conserved element of the innate immune mechanism. It comprises of more than 20 serum proteins most of which are synthesized in the liver. These proteins are synthesized as inactive precursor proteins which are activated by appropriate stimuli. The activated forms of these proteins act as proteases and cleave other components successively in amplification pathways leading to exponential generation of final effectors. Three major pathways of complement pathways have been described, namely the classical, alternative and lectin pathways which are activated by different stimuli. However, all the 3 pathways converge on Complement C3. Cleavage of C3 and C5 successively leads to the production of the membrane attack complex which is final common effector. Excessive and uncontrolled activation of the complement has been implicated in the host of autoimmune diseases. But the complement has also been bemusedly described as the proverbial "double edged sword". On one hand, complement is the final effector of tissue injury in autoimmune diseases and on the other, deficiencies of some components of the complement can result in autoimmune diseases. Currently available tools such as enzyme based immunoassays for functional assessment of complement pathways, flow cytometry, next generation sequencing and proteomics-based approaches provide an exciting opportunity to study this ancient yet mysterious element of innate immunity.

  12. CR2-mediated activation of the complement alternative pathway results in formation of membrane attack complexes on human B lymphocytes

    DEFF Research Database (Denmark)

    Nielsen, C H; Marquart, H V; Prodinger, W M;

    2001-01-01

    Normal human B lymphocytes activate the alternative pathway of complement via complement receptor type 2 (CR2, CD21), that binds hydrolysed C3 (iC3) and thereby promotes the formation of a membrane-bound C3 convertase. We have investigated whether this might lead to the generation of a C5...... convertase and consequent formation of membrane attack complexes (MAC). Deposition of C3 fragments and MAC was assessed on human peripheral B lymphocytes in the presence of 30% autologous serum containing 4.4 mM MgCl2/20 mM EGTA, which abrogates the classical pathway of complement without affecting...... the alternative pathway. Blockade of the CR2 ligand-binding site with the monoclonal antibody FE8 resulted in 56 +/- 13% and 71 +/- 9% inhibition of the C3-fragment and MAC deposition, respectively, whereas the monoclonal antibody HB135, directed against an irrelevant CR2 epitope, had no effect. Blockade...

  13. Complement activation in the context of stem cells and tissue repair

    Institute of Scientific and Technical Information of China (English)

    Ingrid; U; Schraufstatter; Sophia; K; Khaldoyanidi; Richard; G; DiScipio

    2015-01-01

    The complement pathway is best known for its role in immune surveillance and inflammation. However,its ability of opsonizing and removing not only pathogens,but also necrotic and apoptotic cells,is a phylogenetically ancient means of initiating tissue repair. The means and mechanisms of complement-mediated tissue repair are discussed in this review. There is increasing evidence that complement activation contributes to tissue repair at several levels. These range from the chemo-attraction of stem and progenitor cells to areas of complement activation,to increased survival of various cell types in the presence of split products of complement,and to the production of trophic factors by cells activated by the anaphylatoxins C3 a and C5 a. This repair aspect of complement biology has not found sufficient appreciation until recently. The following will examine this aspect of complement biology with an emphasis on the anaphylatoxins C3 a and C5 a.

  14. [The changes of complement activities in sera of mice after subcutaneous administration of beryllium chloride].

    Science.gov (United States)

    Sakaguchi, T; Sakaguchi, S; Nakamura, I; Kudo, Y

    1996-02-01

    We studied changes of the complement pathway activities and the content of C3 in sera of mice, administered BeCl2 (containing 5 micrograms of Be per mouse) or CuCl2 (containing 5 micrograms of Cu per mouse) by a single subcutaneous injection. The value of the classical complement pathway activity (CH50) of the Be group 3 days after administration was significantly higher than that of the control group (P < 0.001). It was significantly lower than in the control group after 7 days (P < 0.001). On the other hand, the CH50 value of the Cu group 3 hr after administration tended to increase, however, it was significantly lower than in the control group after 7 days (P < 0.01). The change of the alternative complement pathway activity (ACH50) value of the Be group was similar to the change of the CH50 value of the group. The ACH50 value of the Cu group 3 days after administration tended to increase but it was the same as the ACH50 value of the control group after 7 days. The C3 contents of both the Be and Cu groups 3 days after administration were significantly higher than in the control group (P < 0.001). The aspartate aminotransferase (AST) activity of the Be group 7 days after administration was significantly higher than that of the control group (P < 0.01). By contrast, AST activity of the Cu group 3 hr after administration was significantly higher than in the control group (P < 0.05). The value of the alanine aminotransferase (ALT) activity of the Be group was low (P < 0.01), but that of the Cu group was high (P < 0.05), 3 hr after administration. These values of both groups after 7 days, however, were significantly higher than in the control group (P < 0.05). The AST/ALT ratio in mice was very high at 3 hr, and it remained high by 7 days after Be injection. On the other hand, the ratio of the Cu group was almost constant for 7 days after Cu injection. Thus, these values changed with relative expedition after Be injection. Therefore, we confirmed that measurements of

  15. Immune complement activation is attenuated by surface nanotopography

    Directory of Open Access Journals (Sweden)

    Elwing H

    2011-10-01

    Full Text Available Mats Hulander1, Anders Lundgren1, Mattias Berglin1, Mattias Ohrlander2, Jukka Lausmaa3,4, Hans Elwing1 1Department of Cell and Molecular Biology/Interface Biophysics, University of Gothenburg, Medicinaregatan 9E, Gothenburg, 2Bactiguard AB, Stockholm, 3SP Technical Research Institute, Boras, 4Biomatcell, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden Abstract: The immune complement (IC is a cell-free protein cascade system, and the first part of the innate immune system to recognize foreign objects that enter the body. Elevated activation of the system from, for example, biomaterials or medical devices can result in both local and systemic adverse effects and eventually loss of function or rejection of the biomaterial. Here, the researchers have studied the effect of surface nanotopography on the activation of the IC system. By a simple nonlithographic process, gold nanoparticles with an average size of 58 nm were immobilized on a smooth gold substrate, creating surfaces where a nanostructure is introduced without changing the surface chemistry. The activation of the IC on smooth and nanostructured surfaces was viewed with fluorescence microscopy and quantified with quartz crystal microbalance with dissipation monitoring in human serum. Additionally, the ability of pre-adsorbed human immunoglobulin G (IgG (a potent activator of the IC to activate the IC after a change in surface hydrophobicity was studied. It was found that the activation of the IC was significantly attenuated on nanostructured surfaces with nearly a 50% reduction, even after pre-adsorption with IgG. An increase in surface hydrophobicity blunted this effect. The possible role of the curvature of the nanoparticles for the orientation of adsorbed IgG molecules, and how this can affect the subsequent activation of the IC, are discussed. The present findings are important for further understanding of how surface nanotopography affects complex protein

  16. TFPI inhibits lectin pathway of complement activation by direct interaction with MASP-2.

    Science.gov (United States)

    Keizer, Mischa P; Pouw, Richard B; Kamp, Angela M; Patiwael, Sanne; Marsman, Gerben; Hart, Margreet H; Zeerleder, Sacha; Kuijpers, Taco W; Wouters, Diana

    2015-02-01

    The lectin pathway (LP) of complement has a protective function against invading pathogens. Recent studies have also shown that the LP plays an important role in ischemia/reperfusion (I/R)-injury. MBL-associated serine protease (MASP)-2 appears to be crucial in this process. The serpin C1-inhibitor is the major inhibitor of MASP-2. In addition, aprotinin, a Kunitz-type inhibitor, was shown to inhibit MASP-2 activity in vitro. In this study we investigated whether the Kunitz-type inhibitor tissue factor pathway inhibitor (TFPI) is also able to inhibit MASP-2. Ex vivo LP was induced and detected by C4-deposition on mannan-coated plates. The MASP-2 activity was measured in a fluid-phase chromogenic assay. rTFPI in the absence or presence of specific monoclonal antibodies was used to investigate which TFPI-domains contribute to MASP-2 inhibition. Here, we identify TFPI as a novel selective inhibitor of MASP-2, without affecting MASP-1 or the classical pathway proteases C1s and C1r. Kunitz-2 domain of TFPI is required for the inhibition of MASP-2. Considering the role of MASP-2 in complement-mediated I/R-injury, the inhibition of this protease by TFPI could be an interesting therapeutic approach to limit the tissue damage in conditions such as cerebral stroke, myocardial infarction or solid organ transplantation.

  17. In-vitro activation of complement system by lactic acidosis in newborn and adults

    Directory of Open Access Journals (Sweden)

    Friederike Hecke

    2001-01-01

    Full Text Available Introduction: Complement activation occurs secondary to a variety of external stimuli. Lactic acidosis has been previously shown to activate the complement factors C3a and C5a. In the present investigation we examined the differential effect of lactic acidosis on anaphylatoxin levels in cord and adult blood. Furthermore we aimed to determine if the entire complement cascade could be activated by lactic acidosis.

  18. Functional analysis of Ficolin-3 mediated complement activation

    DEFF Research Database (Denmark)

    Hein, Estrid; Honoré, Christian; Skjoedt, Mikkel-Ole

    2010-01-01

    The recognition molecules of the lectin complement pathway are mannose-binding lectin and Ficolin -1, -2 and -3. Recently deficiency of Ficolin-3 was found to be associated with life threatening infections. Thus, we aimed to develop a functional method based on the ELISA platform for evaluating...... on acBSA were dependent only on Ficolin-3 in appropriate serum dilutions. Deposition of down stream complement components correlated highly significantly with the serum concentration of Ficolin-3 but not with Ficolin-2 in healthy donors. To make the assay robust for clinical use a chemical compound...... the possibility to diagnose functional and genetic defects of Ficolin-3 and down stream components in the lectin complement pathway....

  19. Regulator of complement activation (RCA) gene cluster in Xenopus tropicalis.

    Science.gov (United States)

    Oshiumi, Hiroyuki; Suzuki, Yuzuru; Matsumoto, Misako; Seya, Tsukasa

    2009-05-01

    Genome and expressed sequence tag information of Xenopus tropicalis suggested that short-consensus repeat (SCR)-containing proteins are encoded by three genes that are mapped within a 300-kb downstream of PFKFB2, which is a marker gene for the regulator of complement activation (RCA) loci in human and chicken. Based on this observation, we cloned the three cDNAs of these proteins using 3'- or 5'-RACE technique. Since their primary structures and locations of the proximity to the PFKFB2 locus, we named them amphibian RCA protein (ARC) 1, 2, and 3. Expression in human HEK293 or CHO cells suggested that ARC1 is a soluble protein of Mr approximately 67 kDa, ARC2 is a membrane protein with Mr 44 kDa, and ARC3 a secretary protein with a putative transmembrane region. They were N-glycosylated during maturation. In human and chicken RCA clusters, the order in which genes for soluble, GPI-anchored, and membrane forms of SCR proteins are arranged is from the distant to proximity to the PFKFB2 gene. However, the amphibian ARC1, 2, and 3 resembled one another and did not reflect the same order found in human and chicken RCA genes. This may be due to self-duplication of ARCs to form a family, and it evolved after the amphibia separated from the ancestor of the amniotes, which possessed soluble, GPI-anchored, and membrane forms of SCR protein members. Taken together, frog possesses a RCA locus, but the constitution of the ARC proteins differs from that of the amniotes with a unique self-resemblance.

  20. Complement activation by salivary agglutinin is secretor status dependent

    NARCIS (Netherlands)

    Gunput, S.T.G.; Ligtenberg, A.J.M.; Terlouw, B.; Brouwer, M.; Veerman, E.C.I.; Wouters, D.

    2015-01-01

    After mucosal damage or gingival inflammation, complement proteins leak into the oral cavity and mix with salivary proteins such as salivary agglutinin (SAG/gp-340/DMBT1). This protein is encoded by the gene Deleted in Malignant Brain Tumors 1 (DMBT1), and it aggregates bacteria, viruses and fungi,

  1. Functional analysis of Ficolin-3 mediated complement activation

    DEFF Research Database (Denmark)

    Hein, Estrid; Honoré, Christian; Skjoedt, Mikkel-Ole;

    2010-01-01

    The recognition molecules of the lectin complement pathway are mannose-binding lectin and Ficolin -1, -2 and -3. Recently deficiency of Ficolin-3 was found to be associated with life threatening infections. Thus, we aimed to develop a functional method based on the ELISA platform for evaluating...

  2. In situ complement activation by polyethylene wear debris.

    NARCIS (Netherlands)

    DeHeer, D.H.; Engels, J.A.; Vries, A.S. de; Knapp, R.H.; Beebe, J.D.

    2001-01-01

    A frequent long-term complication of total joint arthroplasty is aseptic loosening, the end result of wear debris accumulation, synovitis, and osteolysis about the implant-bone or cement-bone interface. Complement, an effector system in plasma, synovial fluid, and tissue, has powerful chemotactic, i

  3. Neutrophil extracellular traps that are not degraded in systemic lupus erythematosus activate complement exacerbating the disease.

    Science.gov (United States)

    Leffler, Jonatan; Martin, Myriam; Gullstrand, Birgitta; Tydén, Helena; Lood, Christian; Truedsson, Lennart; Bengtsson, Anders A; Blom, Anna M

    2012-04-01

    Ongoing inflammation including activation of the complement system is a hallmark of systemic lupus erythematosus (SLE). Antimicrobial neutrophil extracellular traps (NETs) are composed of secreted chromatin that may act as a source of autoantigens typical for SLE. In this study, we investigated how complement interacts with NETs and how NET degradation is affected by complement in SLE patients. We found that sera from a subset of patients with active SLE had a reduced ability to degrade in vitro-generated NETs, which was mostly restored when these patients were in remission. Patients that failed to degrade NETs had a more active disease and they also displayed lower levels of complement proteins C4 and C3 in blood. We discovered that NETs activated complement in vitro and that deposited C1q inhibited NET degradation including a direct inhibition of DNase-I by C1q. Complement deposition on NETs may facilitate autoantibody production, and indeed, Abs against NETs and NET epitopes were more pronounced in patients with impaired ability to degrade NETs. NET-bound autoantibodies inhibited degradation but also further increased C1q deposition, potentially exacerbating the disease. Thus, NETs are a potent complement activator, and this interaction may play an important role in SLE. Targeting complement with inhibitors or by removing complement activators such as NETs could be beneficial for patients with SLE.

  4. Structural insight into the recognition of complement C3 activation products by integrin receptors

    DEFF Research Database (Denmark)

    Bajic, Goran

    2015-01-01

    associated with microbes and apoptotic or necrotic cells. Complement not only protects against pathogens but also maintains body homeostasis. Activation of complement leads to cleavage of the complement proteins C4, C3 and C5, and their fragments have effector functions through binding to pathogen surfaces...... fragment C3a called anaphylatoxin. Complement leads to opsonization as the proteolytic fragment C3b becomes covalently linked to the activator surface through a reactive thioester. Self-surfaces are protected by complement regulators, whereas complement activation vividly amplifies on pathogens...... and their clearance by dendritic cells is mediated by αMβ2. The central molecule in my project, αMβ2 integrin, recognizes many diverse ligands including iC3b, but the molecular basis for such recognition was lacking. During my PhD I have obtained a major breakthrough in the dissection of iC3b interaction with αMβ2. I...

  5. Detection and characterisation of Complement protein activity in bovine milk by bactericidal sequestration assay.

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Cecilia Ximénez

    2014-01-01

    Full Text Available 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.

  7. The Role of Properdin in Zymosan- and Escherichia coli-Induced Complement Activation

    DEFF Research Database (Denmark)

    Harboe, Morten; Garred, Peter; Lindstad, Julie K

    2012-01-01

    Properdin is well known as an enhancer of the alternative complement amplification loop when C3 is activated, whereas its role as a recognition molecule of exogenous pathogen-associated molecular patterns and initiator of complement activation is less understood. We therefore studied the role of ...

  8. Targeting complement activation in brain-dead donors improves renal function after transplantation

    NARCIS (Netherlands)

    Damman, Jeffrey; Hoeger, Simone; Boneschansker, Leo; Theruvath, Ashok; Waldherr, Ruediger; Leuvenink, Henri G.; Ploeg, Rutger J.; Yard, Benito A.; Seelen, Marc A.

    2011-01-01

    Kidneys recovered from brain-dead donors have inferior outcomes after transplantation compared to kidneys from living donors. Since complement activation plays an important role in renal transplant related injury, targeting complement activation in brain-dead donors might improve renal function afte

  9. Electroluminescent TCC, C3dg and fB/Bb epitope assays for profiling complement cascade activation in vitro using an activated complement serum calibration standard.

    Science.gov (United States)

    van Vuuren, B Jansen; Bergseth, G; Mollnes, T E; Shaw, A M

    2014-01-15

    Electroluminescent assays for epitopes on the complement components C3dg, terminal complement complex (TCC) and factor B/Bb (fB/Bb) have been developed with capture and detection antibodies to produce detection limits C3dg=91±9ng/mL, TCC=3±0.1ng/mL and fB=55.7±0.1ng/mL. The assay performance was assessed against a series of zymosan and heat aggregated IgG (HAIgG) in vitro activations of complement using a calibrated activated complement serum (ACS) as calibration standard. The ACS standard was stable within 20% accuracy over a 6-month period with freeze-thaw cycles as required. Differential activation of the complement cascade was observed for TCC showing a pseudo-first order formation half-life of 3.5h after activation with zymosan. The C3dg activation fragment indicates a 10% total activation for both activation agents. The kinetic-epitope analysis for fB indicates that the capture epitope is on the fB/Bb protein fragment which can then become covered by the formation of C3bBb or C3bBbP complexes during the time course of the cascade.

  10. Complement activation in Ghanaian children with severe Plasmodium falciparum malaria

    DEFF Research Database (Denmark)

    Helegbe, Gideon K; Goka, Bamenla Q; Kurtzhals, Jørgen

    2007-01-01

    BACKGROUND: Severe anaemia (SA), intravascular haemolysis (IVH) and respiratory distress (RD) are severe forms of Plasmodium falciparum malaria, with RD reported to be of prognostic importance in African children with malarial anaemia. Complement factors have been implicated in the mechanism......55)] in children with discrete clinical forms of P. falciparum malaria. The relationship between the findings and clinical parameters including coma, haemoglobin (Hb) levels and RD were investigated. RESULTS: Of the 484 samples tested, 131(27%) were positive in DCT, out of which 115/131 (87.8%) were...... falciparum malaria, possibly through induction of erythrophagocytosis and haemolysis. In contrast to other studies, this study did not find association between levels of the complement...

  11. Complement activation and expression during chronic relapsing experimental autoimmune encephalomyelitis in the Biozzi ABH mouse.

    Science.gov (United States)

    Ramaglia, V; Jackson, S J; Hughes, T R; Neal, J W; Baker, D; Morgan, B P

    2015-06-01

    Chronic relapsing experimental autoimmune encephalomyelitis (crEAE) in mice recapitulates many of the clinical and histopathological features of human multiple sclerosis (MS), making it a preferred model for the disease. In both, adaptive immunity and anti-myelin T cells responses are thought to be important, while in MS a role for innate immunity and complement has emerged. Here we sought to test whether complement is activated in crEAE and important for disease. Disease was induced in Biozzi ABH mice that were terminated at different stages of the disease to assess complement activation and local complement expression in the central nervous system. Complement activation products were abundant in all spinal cord areas examined in acute disease during relapse and in the progressive phase, but were absent in early disease remission, despite significant residual clinical disease. Local expression of C1q and C3 was increased at all stages of disease, while C9 expression was increased only in acute disease; expression of the complement regulators CD55, complement receptor 1-related gene/protein y (Crry) and CD59a was reduced at all stages of the disease compared to naive controls. These data show that complement is activated in the central nervous system in the model and suggest that it is a suitable candidate for exploring whether anti-complement agents might be of benefit in MS.

  12. Strong complement activation after acute ischemic stroke is associated with unfavorable outcomes

    DEFF Research Database (Denmark)

    Széplaki, Gábor; Szegedi, Róbert; Hirschberg, Kristóf

    2009-01-01

    OBJECTIVE: According to data from animal models, complement activation plays a major role in the brain injury after acute ischemic stroke. Scarce findings are, however, available on the detection of complement activation products in stroke patients. METHODS: We have measured plasma levels...... role in the development of brain infarct. The measurement of complement activation products might help to determine the clinical prognosis after acute ischemic stroke. Furthermore, there is potential usefulness of complement modulating therapy in ischemic stroke....... of the five complement activation products (C1rC1sC1inh, C4d, C3a, C5a and SC5b-9) in samples of 26 patients with ischemic stroke upon admission. Twenty-six patients with severe carotid atherosclerosis served as patient controls. RESULTS: Levels of two activation products (SC5b-9 and C4d)) were significantly...

  13. Aluminum hydroxide adjuvant differentially activates the three complement pathways with major involvement of the alternative pathway.

    Science.gov (United States)

    Güven, Esin; Duus, Karen; Laursen, Inga; Højrup, Peter; Houen, Gunnar

    2013-01-01

    Al(OH)3 is the most common adjuvant in human vaccines, but its mode of action remains poorly understood. Complement involvement in the adjuvant properties of Al(OH)3 has been suggested in several reports together with a depot effect. It is here confirmed that Al(OH)3 treatment of serum depletes complement components and activates the complement system. We show that complement activation by Al(OH)3 involves the three major pathways by monitoring complement components in Al(OH)3-treated serum and in Al(OH)3-containing precipitates. Al(OH)3 activation of complement results in deposition of C3 cleavage products and membrane attack complex (MAC) and in generation of the anaphylatoxins C3a and C5a. Complement activation was time dependent and inhibited by chelation with EDTA but not EGTA+Mg(2+). We thus confirm that Al(OH)3 activates the complement system and show that the alternative pathway is of major importance.

  14. Aluminum hydroxide adjuvant differentially activates the three complement pathways with major involvement of the alternative pathway.

    Directory of Open Access Journals (Sweden)

    Esin Güven

    Full Text Available Al(OH3 is the most common adjuvant in human vaccines, but its mode of action remains poorly understood. Complement involvement in the adjuvant properties of Al(OH3 has been suggested in several reports together with a depot effect. It is here confirmed that Al(OH3 treatment of serum depletes complement components and activates the complement system. We show that complement activation by Al(OH3 involves the three major pathways by monitoring complement components in Al(OH3-treated serum and in Al(OH3-containing precipitates. Al(OH3 activation of complement results in deposition of C3 cleavage products and membrane attack complex (MAC and in generation of the anaphylatoxins C3a and C5a. Complement activation was time dependent and inhibited by chelation with EDTA but not EGTA+Mg(2+. We thus confirm that Al(OH3 activates the complement system and show that the alternative pathway is of major importance.

  15. Aluminum Hydroxide Adjuvant Differentially Activates the Three Complement Pathways with Major Involvement of the Alternative Pathway

    Science.gov (United States)

    Güven, Esin; Duus, Karen; Laursen, Inga; Højrup, Peter; Houen, Gunnar

    2013-01-01

    Al(OH)3 is the most common adjuvant in human vaccines, but its mode of action remains poorly understood. Complement involvement in the adjuvant properties of Al(OH)3 has been suggested in several reports together with a depot effect. It is here confirmed that Al(OH)3 treatment of serum depletes complement components and activates the complement system. We show that complement activation by Al(OH)3 involves the three major pathways by monitoring complement components in Al(OH)3-treated serum and in Al(OH)3-containing precipitates. Al(OH)3 activation of complement results in deposition of C3 cleavage products and membrane attack complex (MAC) and in generation of the anaphylatoxins C3a and C5a. Complement activation was time dependent and inhibited by chelation with EDTA but not EGTA+Mg2+. We thus confirm that Al(OH)3 activates the complement system and show that the alternative pathway is of major importance. PMID:24040248

  16. Complement activation by cholesterol crystals triggers a subsequent cytokine response

    DEFF Research Database (Denmark)

    Niyonzima, Nathalie; Halvorsen, Bente; Sporsheim, Bjørnar

    2017-01-01

    may under certain circumstances drive processes leading to adverse inflammation. One example is cholesterol crystals (CC) that accumulate in the vessel wall during early phases of atherogenesis and represent an important endogenous danger signal promoting inflammation. CC is recognized by the lectin...... of inflammation processes before downstream release of cytokines including IL-1β. Another therapeutic candidate can be broad-acting 2-hydroxypropyl-β-cyclodextrin, a compound that targets several mechanisms such as cholesterol efflux, complement gene expression, and the NLRP3 pathway. In summary, emerging...

  17. The Emerging Role of Complement Lectin Pathway in Trypanosomatids: Molecular Bases in Activation, Genetic Deficiencies, Susceptibility to Infection, and Complement System-Based Therapeutics

    Directory of Open Access Journals (Sweden)

    Ingrid Evans-Osses

    2013-01-01

    Full Text Available The innate immune system is evolutionary and ancient and is the pivotal line of the host defense system to protect against invading pathogens and abnormal self-derived components. Cellular and molecular components are involved in recognition and effector mechanisms for a successful innate immune response. The complement lectin pathway (CLP was discovered in 1990. These new components at the complement world are very efficient. Mannan-binding lectin (MBL and ficolin not only recognize many molecular patterns of pathogens rapidly to activate complement but also display several strategies to evade innate immunity. Many studies have shown a relation between the deficit of complement factors and susceptibility to infection. The recently discovered CLP was shown to be important in host defense against protozoan microbes. Although the recognition of pathogen-associated molecular patterns by MBL and Ficolins reveal efficient complement activations, an increase in deficiency of complement factors and diversity of parasite strategies of immune evasion demonstrate the unsuccessful effort to control the infection. In the present paper, we will discuss basic aspects of complement activation, the structure of the lectin pathway components, genetic deficiency of complement factors, and new therapeutic opportunities to target the complement system to control infection.

  18. Tissue microarray methodology identifies complement pathway activation and dysregulation in progressive multiple sclerosis.

    Science.gov (United States)

    Loveless, Sam; Neal, James W; Howell, Owain W; Harding, Katharine E; Sarkies, Patrick; Evans, Rhian; Bevan, Ryan J; Hakobyan, Svetlana; Harris, Claire L; Robertson, Neil P; Morgan, Bryan Paul

    2017-07-14

    The complement pathway has potential contributions to both white (WM) and grey matter (GM) pathology in Multiple Sclerosis (MS). A quantitative assessment of complement involvement is lacking. Here we describe the use of Tissue MicroArray (TMA) methodology in conjunction with immunohistochemistry to investigate the localization of complement pathway proteins in progressive MS cortical GM and subcortical WM. Antibodies targeting complement proteins C1q, C3b, regulatory proteins C1 inhibitor (C1INH, complement receptor 1 (CR1), clusterin, factor H (FH) and the C5a anaphylatoxin receptor (C5aR) were utilised alongside standard markers of tissue pathology. All stained slides were digitised for quantitative analysis. We found that numbers of cells immunolabelled for HLA-DR, GFAP, C5aR, C1q and C3b were increased in WM lesions (WML) and GM lesions (GML) compared to normal appearing WM (NAWM) and GM (NAGM), respectively. The complement regulators C1INH, CR1, FH and clusterin were more abundant in WM lesions, while the number of C1q+ neurons were increased and the number of C1INH+, clusterin+, FH+ and CR1+ neurons decreased in GM lesions. The number of complement component positive cells (C1q, C3b) correlated with complement regulator expression in WM, but there was no statistical association between complement activation and regulator expression in the GM. We conclude that TMA methodology and quantitative analysis provides evidence of complement dysregulation in MS GML, including an association of the numerical density of C1q+ cells with tissue lesions. Our work confirms that complement activation and dysregulation occur in all cases of progressive MS and suggest that complement may provide potential biomarkers of the disease. © 2017 International Society of Neuropathology.

  19. Complement Activation Correlates With Disease Severity and Contributes to Cytokine Responses in Plasmodium falciparum Malaria.

    Science.gov (United States)

    Berg, Aase; Otterdal, Kari; Patel, Sam; Gonca, Miguel; David, Catarina; Dalen, Ingvild; Nymo, Stig; Nilsson, Margareta; Nordling, Sofia; Magnusson, Peetra U; Ueland, Thor; Prato, Mauro; Giribaldi, Giuliana; Mollnes, Tom Eirik; Aukrust, Pål; Langeland, Nina; Nilsson, Per H

    2015-12-01

    The impact of complement activation and its possible relation to cytokine responses during malaria pathology was investigated in plasma samples from patients with confirmed Plasmodium falciparum malaria and in human whole-blood specimens stimulated with malaria-relevant agents ex vivo. Complement was significantly activated in the malaria cohort, compared with healthy controls, and was positively correlated with disease severity and with certain cytokines, in particular interleukin 8 (IL-8)/CXCL8. This was confirmed in ex vivo-stimulated blood specimens, in which complement inhibition significantly reduced IL-8/CXCL8 release. P. falciparum malaria is associated with systemic complement activation and complement-dependent release of inflammatory cytokines, of which IL-8/CXCL8 is particularly prominent. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  20. High Complement Factor I Activity in the Plasma of Children with Autism Spectrum Disorders

    Directory of Open Access Journals (Sweden)

    Naghi Momeni

    2012-01-01

    Full Text Available Autism spectrum disorders (ASDs are neurodevelopmental and behavioural syndromes affecting social orientation, behaviour, and communication that can be classified as developmental disorders. ASD is also associated with immune system abnormality. Immune system abnormalities may be caused partly by complement system factor I deficiency. Complement factor I is a serine protease present in human plasma that is involved in the degradation of complement protein C3b, which is a major opsonin of the complement system. Deficiency in factor I activity is associated with an increased incidence of infections in humans. In this paper, we show that the mean level of factor I activity in the ASD group is significantly higher than in the control group of typically developed and healthy children, suggesting that high activity of complement factor I might have an impact on the development of ASD.

  1. Complement Activation and STAT4 Expression Are Associated with Early Inflammation in Diabetic Wounds.

    Science.gov (United States)

    Cunnion, Kenji M; Krishna, Neel K; Pallera, Haree K; Pineros-Fernandez, Angela; Rivera, Magdielis Gregory; Hair, Pamela S; Lassiter, Brittany P; Huyck, Ryan; Clements, Mary A; Hood, Antoinette F; Rodeheaver, George T; Cottler, Patrick S; Nadler, Jerry L; Dobrian, Anca D

    2017-01-01

    Diabetic non-healing wounds are a major clinical problem. The mechanisms leading to poor wound healing in diabetes are multifactorial but unresolved inflammation may be a major contributing factor. The complement system (CS) is the most potent inflammatory cascade in humans and contributes to poor wound healing in animal models. Signal transducer and activator of transcription 4 (STAT4) is a transcription factor expressed in immune and adipose cells and contributes to upregulation of some inflammatory chemokines and cytokines. Persistent CS and STAT4 expression in diabetic wounds may thus contribute to chronic inflammation and delayed healing. The purpose of this study was to characterize CS and STAT4 in early diabetic wounds using db/db mice as a diabetic skin wound model. The CS was found to be activated early in the diabetic wounds as demonstrated by increased anaphylatoxin C5a in wound fluid and C3-fragment deposition by immunostaining. These changes were associated with a 76% increase in nucleated cells in the wounds of db/db mice vs. The novel classical CS inhibitor, Peptide Inhibitor of Complement C1 (PIC1) reduced inflammation when added directly or saturated in an acellular skin scaffold, as reflected by reduced CS components and leukocyte infiltration. A significant increase in expression of STAT4 and the downstream macrophage chemokine CCL2 and its receptor CCR2 were also found in the early wounds of db/db mice compared to non-diabetic controls. These studies provide evidence for two new promising targets to reduce unresolved inflammation and to improve healing of diabetic skin wounds.

  2. Complement activation contributes to ventilator-induced lung injury in rats

    NARCIS (Netherlands)

    B. Petersen; T. Busch; J. Gaertner; J.J. Haitsma (Jack); S.C. Krabbendam (Stefan); M. Ebsen (Michael); B.F. Lachmann (Burkhard); U.X. Kaisers

    2016-01-01

    textabstractThe complement system contributes to ventilator induced lung injury (VILI). We hypothesized that pretreatment with the C1 esterase inhibitor (C1INH) Berinert® constrains complement activation consecutively inducing improvements in arterial oxygenation and histological pulmonary damage. A

  3. Complement activation patterns in atypical haemolytic uraemic syndrome during acute phase and in remission

    NARCIS (Netherlands)

    Volokhina, E.B.; Westra, D.; Velden, T.J.A.M. van der; Kar, N.C.A.J. van de; Mollnes, T.E.; Heuvel, B. van den

    2015-01-01

    Atypical haemolytic uraemic syndrome (aHUS) is associated with (genetic) alterations in alternative complement pathway. Nevertheless, comprehensive evidence that the complement system in aHUS patients is more prone to activation is still lacking. Therefore, we performed a thorough analysis of comple

  4. Increased activity of the mannan-binding lectin complement activation pathway in patients with colorectal cancer

    DEFF Research Database (Denmark)

    Ytting, H; Jensenius, Jens Christian; Christensen, I J

    2004-01-01

    in the colon or rectum, and disease stages according to Dukes' classification. No statistical difference (P=0.20) in frequency of MBL deficiency was found between the patients (20%) and the donors (27%). CONCLUSIONS: Overall, the MBL complement activation pathway is significantly increased in patients......BACKGROUND: Postoperative bacterial infectious complications are frequent in patients with colorectal cancer (CRC), with subsequent increased recurrence rates and poor prognosis. Deficiency of the mannan-binding lectin (MBL) complement activation pathway may cause increased risk of infection......: Serum MBL concentrations and MBL/MASP activity were determined using immunofluorometric assays. The levels are presented as the median, inter-quartile range and range. RESULTS: Serum MBL levels were significantly (P

  5. Complement activation in autoimmune demyelination: dual role in neuroinflammation and neuroprotection.

    Science.gov (United States)

    Rus, Horea; Cudrici, Cornelia; Niculescu, Florin; Shin, Moon L

    2006-11-01

    Multiple sclerosis and its animal model experimental allergic encephalomyelitis are inflammatory demyelinating diseases of the central nervous system mediated by activated lymphocytes, macrophages/microglia and the complement system. Complement activation and the C5b-9 terminal complex contribute to the pathogenesis of these diseases through its role to promote demyelination. C5b-9 was also shown to protect oligodendrocytes from apoptosis both in vitro and in vivo. Our findings indicate that activation of complement and C5b-9 assembly plays a pro-inflammatory role in the acute phase, but may also be neuroprotective.

  6. Can bipartite classical information resources be activated?

    CERN Document Server

    Prettico, Giuseppe

    2012-01-01

    Non-additivity is one of the distinctive traits of Quantum Information Theory: the combined use of quantum objects may be more advantageous than the sum of their individual uses. Non-additivity effects have been proven, for example, for quantum channel capacities, entanglement distillation or state estimation. In this work, we consider whether non-additivity effects can be found in Classical Information Theory. We work in the secret-key agreement scenario in which two honest parties, having access to correlated classical data that are also correlated to an eavesdropper, aim at distilling a secret key. Exploiting the analogies between the entanglement and the secret-key agreement scenario, we provide some evidence that the secret-key rate may be a non-additive quantity. In particular, we show that correlations with conjectured bound information become secret-key distillable when combined. Our results constitute a new instance of the subtle relation between the entanglement and secret-key agreement scenario.

  7. Citrem Modulates Internal Nanostructure of Glyceryl Monooleate Dispersions and Bypasses Complement Activation

    DEFF Research Database (Denmark)

    Wibroe, Peter P; Mat Azmi, Intan Diana Binti; Nilsson, Christa;

    2015-01-01

    Lyotropic non-lamellar liquid crystalline (LLC) aqueous nanodispersions hold a great promise in drug solubilization and delivery, but these nanosystems often induce severe hemolysis and complement activation, which limit their applications for safe intravenous administration. Here, we engineer an...

  8. Single-Walled Carbon Nanotube Surface Control of Complement Recognition and Activation

    DEFF Research Database (Denmark)

    Andersen, Alina Joukainen; Robinson, Joshua T.; Dai, Hongjie

    2013-01-01

    Carbon nanotubes (CNTs) are receiving considerable attention in site-specific drug and nucleic acid delivery, photodynamic therapy, and photoacoustic molecular imaging. Despite these advances, nanotubes may activate the complement system (an integral part of innate immunity), which can induce...

  9. Protein engineering to target complement evasion in cancer.

    Science.gov (United States)

    Carter, Darrick; Lieber, André

    2014-01-21

    The complement system is composed of soluble factors in plasma that enhance or "complement" immune-mediated killing through innate and adaptive mechanisms. Activation of complement causes recruitment of immune cells; opsonization of coated cells; and direct killing of affected cells through a membrane attack complex (MAC). Tumor cells up-regulate complement inhibitory factors - one of several strategies to evade the immune system. In many cases as the tumor progresses, dramatic increases in complement inhibitory factors are found on these cells. This review focuses on the classic complement pathway and the role of major complement inhibitory factors in cancer immune evasion as well as on how current protein engineering efforts are being employed to increase complement fixing or to reverse complement resistance leading to better therapeutic outcomes in oncology. Strategies discussed include engineering of antibodies to enhance complement fixation, antibodies that neutralize complement inhibitory proteins as well as engineered constructs that specifically target inhibition of the complement system.

  10. On the classical theory of molecular optical activity

    CERN Document Server

    Frolov, Alexei M

    2010-01-01

    The basic principles of classical and semi-classical theories of molecular optical activity are discussed. These theories are valid for dilute solutions of optically active organic molecules. It is shown that all phenomena known in the classical theory of molecular optical activity can be described with the use of one pseudo-scalar which is a uniform function of the incident light frequency $\\omega$. The relation between optical rotation and circular dichroism is derived from the basic Kramers-Kronig relations. In our discussion of the general theory of molecular optical activity we introduce the tensor of molecular optical activity. It is shown that to evaluate the optical rotation and circular dichroism at arbitrary frequencies one needs to know only nine (3 + 6) molecular tensors. The quantum (or semi-classical) theory of molecular optical activity is also briefly discussed. We also raise the possibility of measuring the optical rotation and circular dichroism at wavelengths which correspond to the vacuum ...

  11. Enhancement of antibody-dependent mechanisms of tumor cell lysis by a targeted activator of complement.

    Science.gov (United States)

    Imai, Masaki; Ohta, Rieko; Varela, Juan C; Song, Hongbin; Tomlinson, Stephen

    2007-10-01

    Complement inhibitors expressed on tumor cells provide a hindrance to the therapeutic efficacy of some monoclonal antibodies (mAb). We investigated a novel strategy to overwhelm complement inhibitor activity and amplify complement activation on tumor cells. The C3-binding domain of human complement receptor 2 (CR2; CD21) was linked to the complement-activating Fc region of human IgG1 (CR2-Fc), and the ability of the construct to target and amplify complement deposition on tumor cells was investigated. CR2 binds C3 activation fragments, and CR2-Fc targeted tumor cells by binding to C3 initially deposited by a tumor-specific antibody. Complement deposition on Du145 cells (human prostate cancer cell line) and anti-MUC1 mAb-mediated complement-dependent lysis of Du145 cells were significantly enhanced by CR2-Fc. Anti-MUC1 antibody-dependent cell-mediated cytotoxicity of Du145 by human peripheral blood mononuclear cells was also significantly enhanced by CR2-Fc in both the presence and the absence of complement. Radiolabeled CR2-Fc targeted to s.c. Du145 tumors in nude mice treated with anti-MUC1 mAb, validating the targeting strategy in vivo. A metastatic model was used to investigate the effect of CR2-Fc in a therapeutic paradigm. Administration of CR2-Fc together with mAb therapy significantly improved long-term survival of nude mice challenged with an i.v. injection of EL4 cells. The data show that CR2-Fc enhances the therapeutic efficacy of antibody therapy, and the construct may provide particular benefits under conditions of limiting antibody concentration or low tumor antigen density.

  12. Collectin-11/MASP complex formation triggers activation of the lectin complement pathway--the fifth lectin pathway initiation complex

    DEFF Research Database (Denmark)

    Ma, Ying Jie; Skjoedt, Mikkel-Ole; Garred, Peter

    2013-01-01

    complement pathway regulator MAP-1. Furthermore, we found that complex formation between recombinant collectin-11 and recombinant MASP-2 on Candida albicans leads to deposition of C4b. Native collectin-11 in serum mediated complement activation and deposition of C4b and C3b, and formation of the terminal...... complement complex on C. albicans. Moreover, spiking collectin-11-depleted serum, which did not mediate complement activation, with recombinant collectin-11 restored the complement activation capability. These results define collectin-11 as the fifth recognition molecule in the lectin complement pathway...

  13. A novel method for direct measurement of complement convertases activity in human serum.

    Science.gov (United States)

    Blom, A M; Volokhina, E B; Fransson, V; Strömberg, P; Berghard, L; Viktorelius, M; Mollnes, T E; López-Trascasa, M; van den Heuvel, L P; Goodship, T H; Marchbank, K J; Okroj, M

    2014-10-01

    Complement convertases are enzymatic complexes that play a central role in sustaining and amplification of the complement cascade. Impairment of complement function leads directly or indirectly to pathological conditions, including higher infection rate, kidney diseases, autoimmune- or neurodegenerative diseases and ischaemia-reperfusion injury. An assay for direct measurement of activity of the convertases in patient sera is not available. Existing assays testing convertase function are based on purified complement components and, thus, convertase formation occurs under non-physiological conditions. We designed a new assay, in which C5 blocking compounds enabled separation of the complement cascade into two phases: the first ending at the stage of C5 convertases and the second ending with membrane attack complex formation. The use of rabbit erythrocytes or antibody-sensitized sheep erythrocytes as the platforms for convertase formation enabled easy readout based on measurement of haemolysis. Thus, properties of patient sera could be studied directly regarding convertase activity and membrane attack complex formation. Another advantage of this assay was the possibility to screen for host factors such as C3 nephritic factor and other anti-complement autoantibodies, or gain-of-function mutations, which prolong the half-life of complement convertases. Herein, we present proof of concept, detailed description and validation of this novel assay.

  14. Increased activity of the complement system in the liver of patients with alcoholic hepatitis.

    Science.gov (United States)

    Shen, Hong; French, Barbara A; Liu, Hui; Tillman, Brittany C; French, Samuel W

    2014-12-01

    Inflammation has been suggested as a mechanism underlying the development of alcoholic hepatitis (AH). The activation of the complement system plays an important role in inflammation. Although it has been shown that ethanol-induced activation of the complement system contributes to the pathophysiology of ethanol-induced liver injury in mice, whether ethanol consumption activates the complement system in the human liver has not been investigated. Using antibodies against C1q, C3, and C5, the immunoreactivity of the complement system in patients with AH was examined by immunohistochemistry and quantified by morphometric image analysis. The immunoreactivity intensity of C1q, C3, and C5 in patients with AH was significantly higher than that seen in normal controls. Further, the gene expression of C1q, C3, and C5 was examined using real-time PCR. There were increases in the levels of C1q and C5, but not C3 mRNA in AH. Moreover, the immunoreactivity of C5a receptor (C5aR) also increased in AH. To explore the functional implication of the activation of the complement system in AH, we examined the colocalization of C5aR in Mallory-Denk bodies (MDBs) forming balloon hepatocytes. C5aR was focally overexpressed in the MDB forming cells. Collectively, our study suggests that alcohol consumption increases the activity of the complement system in the liver cells, which contributes to the inflammation-associated pathogenesis of AH.

  15. Complement Activation: An Emerging Player in the Pathogenesis of Cardiovascular Disease

    Science.gov (United States)

    Carter, Angela M.

    2012-01-01

    A wealth of evidence indicates a fundamental role for inflammation in the pathogenesis of cardiovascular disease (CVD), contributing to the development and progression of atherosclerotic lesion formation, plaque rupture, and thrombosis. An increasing body of evidence supports a functional role for complement activation in the pathogenesis of CVD through pleiotropic effects on endothelial and haematopoietic cell function and haemostasis. Prospective and case control studies have reported strong relationships between several complement components and cardiovascular outcomes, and in vitro studies and animal models support a functional effect. Complement activation, in particular, generation of C5a and C5b-9, influences many processes involved in the development and progression of atherosclerosis, including promotion of endothelial cell activation, leukocyte infiltration into the extracellular matrix, stimulation of cytokine release from vascular smooth muscle cells, and promotion of plaque rupture. Complement activation also influences thrombosis, involving components of the mannose-binding lectin pathway, and C5b-9 in particular, through activation of platelets, promotion of fibrin formation, and impairment of fibrinolysis. The participation of the complement system in inflammation and thrombosis is consistent with the physiological role of the complement system as a rapid effector system conferring protection following vessel injury. However, in the context of CVD, these same processes contribute to development of atherosclerosis, plaque rupture, and thrombosis. PMID:24278688

  16. Complement Activation: An Emerging Player in the Pathogenesis of Cardiovascular Disease

    Directory of Open Access Journals (Sweden)

    Angela M. Carter

    2012-01-01

    Full Text Available A wealth of evidence indicates a fundamental role for inflammation in the pathogenesis of cardiovascular disease (CVD, contributing to the development and progression of atherosclerotic lesion formation, plaque rupture, and thrombosis. An increasing body of evidence supports a functional role for complement activation in the pathogenesis of CVD through pleiotropic effects on endothelial and haematopoietic cell function and haemostasis. Prospective and case control studies have reported strong relationships between several complement components and cardiovascular outcomes, and in vitro studies and animal models support a functional effect. Complement activation, in particular, generation of C5a and C5b-9, influences many processes involved in the development and progression of atherosclerosis, including promotion of endothelial cell activation, leukocyte infiltration into the extracellular matrix, stimulation of cytokine release from vascular smooth muscle cells, and promotion of plaque rupture. Complement activation also influences thrombosis, involving components of the mannose-binding lectin pathway, and C5b-9 in particular, through activation of platelets, promotion of fibrin formation, and impairment of fibrinolysis. The participation of the complement system in inflammation and thrombosis is consistent with the physiological role of the complement system as a rapid effector system conferring protection following vessel injury. However, in the context of CVD, these same processes contribute to development of atherosclerosis, plaque rupture, and thrombosis.

  17. Anti-microbial activity and anti-complement activity of extracts obtained from selected Hawaiian medicinal plants.

    Science.gov (United States)

    Locher, C P; Burch, M T; Mower, H F; Berestecky, J; Davis, H; Van Poel, B; Lasure, A; Vanden Berghe, D A; Vlietinck, A J

    1995-11-17

    Selected plants having a history of use in Polynesian traditional medicine for the treatment of infectious disease were investigated for anti-viral, anti-fungal and anti-bacterial activity in vitro. Extracts from Scaevola sericea, Psychotria hawaiiensis, Pipturus albidus and Eugenia malaccensis showed selective anti-viral activity against Herpes Simplex Virus-1 and 2 and Vesicular Stomatitis Virus. Aleurites moluccana extracts showed anti-bacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa, while Pipturus albidus and Eugenia malaccensis extracts showed growth inhibition of Staphylococcus aureus and Streptococcus pyogenes. Psychotria hawaiiensis and Solanum niger inhibited growth of the fungi Microsporum canis, Trichophyton rubrum and Epidermophyton floccosum, while Ipomoea sp., Pipturus albidus, Scaevola sericea, Eugenia malaccensis, Piper methysticum, Barringtonia asiatica and Adansonia digitata extracts showed anti-fungal activity to a lesser extent. Eugenia malaccensis was also found to inhibit the classical pathway of complement suggesting that an immunological basis for its in vivo activity was identified. This study has confirmed some of the ethnobotanical reports of Hawaiian medicinal plants having curative properties against infections using biological assays in vitro.

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

    Science.gov (United States)

    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.

  19. Interrelation Between Oxidative Stress and Complement Activation in Models of Age-Related Macular Degeneration.

    Science.gov (United States)

    Pujol-Lereis, Luciana M; Schäfer, Nicole; Kuhn, Laura B; Rohrer, Bärbel; Pauly, Diana

    2016-01-01

    Millions of individuals older than 50-years suffer from age-related macular degeneration (AMD). Associated with this multifactorial disease are polymorphisms of complement factor genes and a main environmental risk factor-oxidative stress. Until now the linkage between these risk factors for AMD has not been fully understood. Recent studies, integrating results on oxidative stress, complement activation, epidemiology and ocular pathology suggested the following sequence in AMD-etiology: initially, chronic oxidative stress results in modification of proteins and lipids in the posterior of the eye; these tissue alterations trigger chronic inflammation, involving the complement system; and finally, invasive immune cells facilitate pathology in the retina. Here, we summarize the results for animal studies which aim to elucidate this molecular interplay of oxidative events and tissue-specific complement activation in the eye.

  20. Complement binding to erythrocytes is associated with macrophage activation and reduced haemoglobin in Plasmodium falciparum malaria

    DEFF Research Database (Denmark)

    Goka, B Q; Kwarko, H; Kurtzhals, J A

    2001-01-01

    We have examined IgG and complement factor C3d deposition on erythrocytes by means of the direct Coombs' test (DAT) and looked for an association with the anaemia seen in falciparum malaria in children living in an area of hyperendemic malaria transmission (in Ghana). In one study (in 1997), 53 out....... The studies support the role of complement activation and erythrophagocytosis in the pathogenesis of anaemia in falciparum malaria in African children....

  1. Healing of complement activating Ti implants compared with non-activating Ti in rat tibia.

    Science.gov (United States)

    Harmankaya, N; Igawa, K; Stenlund, P; Palmquist, A; Tengvall, P

    2012-09-01

    Recent studies have revealed that ozone ultraviolet (UVO) illumination of titanium (Ti) implants improves bone-implant anchorage by altering the physico-chemical and immune activating properties of the titanium dioxide (TiO(2)) layer. In the present rat tibia model, the authors compared the early events of inflammation and bone formation around UVO-treated Ti and complement activating immunoglobin g (IgG)-coated Ti. Machined Ti and machined Ti coated with a physical vapour-deposited Ti layer were used as references. Screw-shaped test and reference implants were implanted into rat tibia and harvested after 1, 7 and 28 days. Messenger RNA expression of implant adhered cells and peri-implant tissue ~250 μm from the surface were subsequently analysed with regard to IL-1β, TNF-α, osteocalcin, cathepsin K, BMP-2 and PDGF. Separate implants were retrieved after 7 and 28 days for removal torque measurements, and histological staining and histomorphometric analysis of bone area and bone-to-implant contact. While enhanced expression of inflammatory markers, TNF-α and IL-1β, was observed on IgG-coated surfaces throughout the observation time, UVO-treated surfaces indicated a significantly lower early inflammatory response. In the early phases (1 and 7 days), the UVO-treated surfaces displayed a significantly higher expression of osteoblast markers BMP-2 and osteocalcin. In summary, complement activating Ti implants elicited a stronger inflammatory response than UVO-treated Ti, with low complement activation during the first week of healing. In spite of this, the UVO-treated Ti induced only marginally more bone growth outside the implants.

  2. Assessment of in vivo complement activation on the Echinococcus granulosus hydatid cyst wall.

    Science.gov (United States)

    Ferreira, A M; Diaz, A; Fernandez, C; Sim, R B

    2001-12-01

    The larval stage of the parasite Echinococcus granulosus causes hydatid disease. The hydatid cyst is potentially capable of activating host complement, since it is a large, persistent, carbohydrate-rich structure, coated with host immunoglobulins, and localized in the host's internal organs. Nonetheless, in vitro studies have suggested that the cyst surface, the hydatid cyst wall (HCW), is a poor complement activator. In this study, we assessed the occurrence of in vivo complement activation on the hydatid cyst by measuring the levels of two complement activation products, C3d and complexes bearing a C9 activation neoepitope (TCC/MAC), in extracts from HCW of human origin. Low amounts of C3d and TCC/MAC were found in HCW in comparison with their levels in normal human plasma and activated human sera, suggesting that in vivo complement activation on HCW is efficiently down-regulated. This regulation may contribute to limit host inflammation which has been observed to correlate with parasite degeneration and death.

  3. Deficiencies and excessive human complement system activation in disorders of multifarious etiology.

    Science.gov (United States)

    Tichaczek-Goska, Dorota

    2012-01-01

    Complement is an integral part of the immune system protecting the host organism against invasion and proliferation of various microorganisms. It is also involved in the removal of the body's own damaged and altered cells. Activation of the complement system is a very precise process and it is strictly controlled by regulatory proteins present in both plasma and at host cells' surfaces. C3 protein plays a major role in the complement activation and generation of immune responses. Deficiencies of the C3 and other complement components, so-called early and late complement proteins, contribute to the emergence of recurrent bacterial, viral and fungal infections. The low level of mannose-binding lectin is also important. This protein plays a protective role in the early stages of infection and in the control of inflammation. Its deficit is one of the most common reasons for human immunodeficiency, observed in microbial infections as well as in autoimmune diseases such as rheumatoid arthritis. On the other hand, the excessive activation of complement proteins is often discovered to be the reason for many diseases. These include e.g. autoimmune diseases, Alzheimer's syndrome, schizophrenia, atypical hemolytic-uremic syndrome, angioedema, macular degeneration, and Crohn's disease.

  4. A NEW METHOD TO ASSESS FUNCTIONAL ACTIVITY OF SERUM COMPLEMENT SYSTEM

    Directory of Open Access Journals (Sweden)

    E. G. Cheremnykh

    2015-01-01

    Full Text Available Complement system is an important component of innate immunity, providing primary protection against pathogens invading the body. In addition, it was shown that the complement system is associated with many diseases, not only autoimmune and infectious, but also mental disorders. In this regard, it is necessary to develop affordable and fast method of measuring activity of the complement system in real-time mode. We present a new semi-automated method for assessment of serum complement activity. The assay is based on cytolytic action of complement system upon the ciliate organism Tetrahymena pyriformis. This method consists in repeated counting of live Tetrahymena motile cells by means of specially developed Biolat device, which consists of two video cameras, light sources, and movable round plate. The plate has two rows of holes. The device also includes microprocessor control unit based on AutoCiliata software, intended for control of operation module and counting the surviving cell. The calculations are based on fixation of two sequential video-frames, with subsequent software image processing. Cell death events were observed upon incubation in triethanolamine (TEA buffer containing 5% of blood serum. We have also compared complement activity in different buffers, i.e., standard medium for culturing of ciliates, Veronal-Medinalum buffer, and the TEA buffer. TEA buffer was found superior to the Veronal buffer when applied in the test system. The time of cell death in the TEA-buffered medium containing 5% serum was < 15 minutes for all the sera studied. The parameters denoting serum complement activity were as follows: a half-life time for the moving cells (TLD50, and a similar value for 100% cell inactivation (1/TLD50, functional activity of the complement system, ACS. The sensitivity of this assay was calculated from dependencies between TLD50 and ACS, and actual serum concentrations. We have suggested an opportunity for evaluation of an

  5. Complement activation, endothelial dysfunction, insulin resistance and chronic heart failure

    DEFF Research Database (Denmark)

    Bjerre, M.; Kistorp, C.; Hansen, T.K.

    2010-01-01

    CRP), endothelial activation (soluble E-selectin, sEsel)), endothelial damage/dysfunction (von Willebrand factor, vWf) and insulin resistance (IR) and prognosis in CHF remains unknown. Design. We investigated the association(s) between plasma sMAC, hsCRP, sEsel, vWf and IR (assessed by homeostatic model assessment...

  6. Complement activated granulocytes can cause autologous tissue destruction in man

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    E. Löhde

    1992-01-01

    Full Text Available Activation of polymorphonuclear granulocytes (PMNs by C5a is thought to be important in the pathogenesis of multiple organ failure during sepsis and after trauma. In our experiment exposure of human PMNs to autologous zymosan activated plasma (ZAP leads to a rapid increase in chemiluminescence. Heating the ZAP at 56°C for 30 min did not alter the changes, while untreated plasma induced only baseline activity. The respiratory burst could be completely abolished by decomplementation and preincubation with rabbit antihuman C5a antibodies. Observation of human omentum using electron microscopy showed intravascular aggregation of PMNs, with capillary thrombosis and diapedesis of the cells through endothelial junctions 90 s after exposure to ZAP. PMNs caused disruption of connections between the mesothelial cells. After 4 min the mesothelium was completely destroyed, and connective tissue and fat cells exposed. Native plasma and minimum essential medium did not induce any morphological changes. These data support the concept that C5a activated PMNs can cause endothelial and mesothelial damage in man. Even though a causal relationship between anaphylatoxins and organ failure cannot be proved by these experiments C5a seems to be an important mediator in the pathogenesis of changes induced by severe sepsis and trauma in man.

  7. Increased activity of the mannan-binding lectin complement activation pathway in patients with colorectal cancer

    DEFF Research Database (Denmark)

    Ytting, H; Jensenius, J C; Christensen, Ib Jarle

    2004-01-01

    BACKGROUND: Postoperative bacterial infectious complications are frequent in patients with colorectal cancer (CRC), with subsequent increased recurrence rates and poor prognosis. Deficiency of the mannan-binding lectin (MBL) complement activation pathway may cause increased risk of infection...... with colorectal cancer compared with healthy persons. However, similar frequencies of MBL pathway deficiency are observed in patients and healthy persons....... in certain patient groups. It is hypothesized that a deficient MBL pathway might be more frequent among patients with CRC than in healthy individuals. The MBL pathway was therefore evaluated in serum obtained preoperatively from 193 patients with primary CRC and in serum from 150 healthy volunteers. METHODS...

  8. Complement activation in the injured central nervous system: another dual-edged sword?

    Directory of Open Access Journals (Sweden)

    Brennan Faith H

    2012-06-01

    Full Text Available Abstract The complement system, a major component of the innate immune system, is becoming increasingly recognised as a key participant in physiology and disease. The awareness that immunological mediators support various aspects of both normal central nervous system (CNS function and pathology has led to a renaissance of complement research in neuroscience. Various studies have revealed particularly novel findings on the wide-ranging involvement of complement in neural development, synapse elimination and maturation of neural networks, as well as the progression of pathology in a range of chronic neurodegenerative disorders, and more recently, neurotraumatic events, where rapid disruption of neuronal homeostasis potently triggers complement activation. The purpose of this review is to summarise recent findings on complement activation and acquired brain or spinal cord injury, i.e. ischaemic-reperfusion injury or stroke, traumatic brain injury (TBI and spinal cord injury (SCI, highlighting the potential for complement-targeted therapeutics to alleviate the devastating consequences of these neurological conditions.

  9. Remarkable Activation of the Complement System and Aberrant Neuronal Localization of the Membrane Attack Complex in the Brain Tissues of Scrapie-Infected Rodents.

    Science.gov (United States)

    Lv, Yan; Chen, Cao; Zhang, Bao-Yun; Xiao, Kang; Wang, Jing; Chen, Li-Na; Sun, Jing; Gao, Chen; Shi, Qi; Dong, Xiao-Ping

    2015-12-01

    As an integral part of the innate immunity, the complement system has been reported to involve in the pathogenesis of prion diseases (PrD). However, the states of expression and activity of complement proteins in experimental models of scrapie infection are still not fully understood. Herein, the state of complement activation, the presence, and distribution as well as localization of C3 and membrane attack complex (MAC) in the brains of several scrapie-infected rodents were comparatively assessed through various methodologies. Our data illustrated a significant increase in the total complement activity (CH50, U/ml) in several scrapie-infected rodent brains at the terminal stage and a time-dependent upregulation of C1q in 263K-infected hamsters during the incubation period, intimating the sustained and progressive activation of the classical pathway during PrD progression. Confocal microscopy revealed robust activation of C3 and its localization to various central nervous system (CNS) cells with differential morphology in the brain tissues of both 263K-infected hamsters and 139A-infected C57BL/6 mice at disease end stages. Dynamic analyses of MAC in the brains of 263K-infected hamsters and 139A-infected C57BL/6 mice demonstrated remarkably time-dependent deposition during the incubation period, which may highlight a persistently activated terminal complement components. Moreover, immunofluorescent assays (IFAs) showed that MAC-specific signals appeared to overlap with morphologically abnormal neurons rather than proliferative astrocytes or activated microglia throughout the CNS of both 263K-infected hamsters and 139A-infected C57BL/6 mice. Overall, these results indicate that the activation of the complement system and the subsequent localization of the complement components to neurons may be a hallmark during prion infection, which ultimately contribute to the neurodegeneration in PrD.

  10. Role of CD59 in T cell activation induced by non-lethal complement attack

    Institute of Scientific and Technical Information of China (English)

    HAN Gen-cheng; BAI Yun; JIANG Man; LI Wan-ling; ZHU Xi-hua

    2001-01-01

    To study the mechanism ofT-cell activation induced by non-lethal complement attack and the role of CD59 in this process. Methods: Human CD59 and its transmembrane counterpart CD59TM cDNA were transfected into murine thymoma EL-4 cells. Activation and proliferation of EL-4 transfectants were observed with MTT assay.Results: Both CD59 and CD59 TM cDNA expressed on EL-4 cells effectively inhibited complement-mediated membrane damage. Cross-linking of CD59 with antibody induced activation of CD59/EL-4 cells but not CD59TM/EL-4cells. This effect was inhibited by Herbimycin A, a special protein tyrosine kinase (PTK) inhibitor. Non-lethal complement attack induced CD59/EL-4 but not CD59TM/EL-4 cell to proliferate, and this reaction was not blocked by Herbimycin A. Conclusion: CD59 takes part in T cell activation induced by non-lethal complement attack. The mechanisms of T cell activation induced by non-lethal complement attack are different from those by cross-linking of CD59.

  11. Interplay Between Amphioxus Complement with Sea Bass Macrophages: Opsonic Activity of Amphioxus Humoral Fluids

    Institute of Scientific and Technical Information of China (English)

    PAN Junli; LIU Min; ZHANG Shicui

    2011-01-01

    Previous studies have shown the existence of a complement system in the amphioxus Branchiostoma japonicum.However,whether it has an opsonic activity similar to that of vertebrates remains unknown.We demonstrated that the humoral fluid (HF)of amphioxus promoted the phagocytosis of yeast cells with sea bass (Lateolabraxjaponicus) macrophages,whereas the C3-depleted and heated HF significantly lost the phagocytosis-promoting capacity.In addition,the precipitation of factor B (Bf) led to a marked loss of opsonic activity.Moreover,C3 fragments in the HF were found to bind to yeast cell surfaces.The results indicate that the amphioxus complement system is an important element involved in the opsonic activity,which promotes the sea bass macrophage phagocytosis by tagging yeast cells with C3 fragments via the activation of alternative complement pathway.

  12. The complement system in human cardiometabolic disease.

    Science.gov (United States)

    Hertle, E; Stehouwer, C D A; van Greevenbroek, M M J

    2014-10-01

    The complement system has been implicated in obesity, fatty liver, diabetes and cardiovascular disease (CVD). Complement factors are produced in adipose tissue and appear to be involved in adipose tissue metabolism and local inflammation. Thereby complement links adipose tissue inflammation to systemic metabolic derangements, such as low-grade inflammation, insulin resistance and dyslipidaemia. Furthermore, complement has been implicated in pathophysiological mechanisms of diet- and alcohol induced liver damage, hyperglycaemia, endothelial dysfunction, atherosclerosis and fibrinolysis. In this review, we summarize current evidence on the role of the complement system in several processes of human cardiometabolic disease. C3 is the central component in complement activation, and has most widely been studied in humans. C3 concentrations are associated with insulin resistance, liver dysfunction, risk of the metabolic syndrome, type 2 diabetes and CVD. C3 can be activated by the classical, the lectin and the alternative pathway of complement activation; and downstream activation of C3 activates the terminal pathway. Complement may also be activated via extrinsic proteases of the coagulation, fibrinolysis and the kinin systems. Studies on the different complement activation pathways in human cardiometabolic disease are limited, but available evidence suggests that they may have distinct roles in processes underlying cardiometabolic disease. The lectin pathway appeared beneficial in some studies on type 2 diabetes and CVD, while factors of the classical and the alternative pathway were related to unfavourable cardiometabolic traits. The terminal complement pathway was also implicated in insulin resistance and liver disease, and appears to have a prominent role in acute and advanced CVD. The available human data suggest a complex and potentially causal role for the complement system in human cardiometabolic disease. Further, preferably longitudinal studies are needed to

  13. Review on complement analysis method and the roles of glycosaminoglycans in the complement system.

    Science.gov (United States)

    Li, Lian; Li, Yan; Ijaz, Muhammad; Shahbaz, Muhammad; Lian, Qianqian; Wang, Fengshan

    2015-12-10

    Complement system is composed of over 30 proteins and it plays important roles in self-defence and inflammation. There are three activation pathways, including classical pathway, alternative pathway and lectin pathway, in complement system, and they are associated with many diseases such as osteoarthritis and age-related macular degeneration. Modulation of the complement system may be a promising strategy in the treatment of related diseases. Glycosaminoglycans are anionic linear polysaccharides without branches. They are one kind of multi-functional macromolecules which have great potential in regulating complement system. This review is organized around two aspects between the introduction of complement system and the interaction of glycosaminoglycans with complement system. Three complement activation pathways and the biological significance were introduced first. Then functional analysis methods were compared to provide a strategy for potential glycosaminoglycans screen. Finally, the roles of glycosaminoglycans played in the complement system were summed up.

  14. Evolution of the complement system.

    Science.gov (United States)

    Nonaka, Masaru

    2014-01-01

    The mammalian complement system constitutes a highly sophisticated body defense machinery comprising more than 30 components. Research into the evolutionary origin of the complement system has identified a primitive version composed of the central component C3 and two activation proteases Bf and MASP in cnidaria. This suggests that the complement system was established in the common ancestor of eumetazoa more than 500 million years ago. The original activation mechanism of the original complement system is believed to be close to the mammalian lectin and alternative activation pathways, and its main role seems to be opsonization and induction of inflammation. This primitive complement system has been retained by most deuterostomes without major change until the appearance of jawed vertebrates. At this stage, duplication of the C3, Bf and MASP genes as well as recruitment of membrane attack components added the classical and lytic pathways to the primitive complement system, converting it to the modern complement system. In contrast, the complement system was lost multiple times independently in the protostome lineage.

  15. Complement Evasion by Pathogenic Leptospira.

    Science.gov (United States)

    Fraga, Tatiana Rodrigues; Isaac, Lourdes; Barbosa, Angela Silva

    2016-01-01

    Leptospirosis is a neglected infectious disease caused by spirochetes from the genus Leptospira. Pathogenic microorganisms, notably those which reach the blood circulation such as Leptospira, have evolved multiple strategies to escape the host complement system, which is important for innate and acquired immunity. Leptospira avoid complement-mediated killing through: (i) recruitment of host complement regulators; (ii) acquisition of host proteases that cleave complement proteins on the bacterial surface; and, (iii) secretion of proteases that inactivate complement proteins in the Leptospira surroundings. The recruitment of host soluble complement regulatory proteins includes the acquisition of Factor H (FH) and FH-like-1 (alternative pathway), C4b-binding protein (C4BP) (classical and lectin pathways), and vitronectin (Vn) (terminal pathway). Once bound to the leptospiral surface, FH and C4BP retain cofactor activity of Factor I in the cleavage of C3b and C4b, respectively. Vn acquisition by leptospires may result in terminal pathway inhibition by blocking C9 polymerization. The second evasion mechanism lies in plasminogen (PLG) binding to the leptospiral surface. In the presence of host activators, PLG is converted to enzymatically active plasmin, which is able to degrade C3b, C4b, and C5 at the surface of the pathogen. A third strategy used by leptospires to escape from complement system is the active secretion of proteases. Pathogenic, but not saprophytic leptospires, are able to secrete metalloproteases that cleave C3 (central complement molecule), Factor B (alternative pathway), and C4 and C2 (classical and lectin pathways). The purpose of this review is to fully explore these complement evasion mechanisms, which act together to favor Leptospira survival and multiplication in the host.

  16. Depressed activation of the lectin pathway of complement in hereditary angioedema

    DEFF Research Database (Denmark)

    Varga, L; Széplaki, G; Laki, J

    2008-01-01

    ) in three complement activation pathways. Functional activity of the CP, LP and AP were measured in the sera of 68 adult patients with hereditary angioedema (HAE) and 64 healthy controls. In addition, the level of C1q, MBL, MBL-associated serine protease-2 (MASP-2), C4-, C3- and C1INH was measured...

  17. Classroom Active Learning Complemented by an Online Discussion Forum to Teach Sustainability

    Science.gov (United States)

    Dengler, Mary

    2008-01-01

    This paper identifies some of the pedagogical benefits of an active learning course delivery complemented by an online discussion forum to teach sustainability by evaluating the case of a geography master's course. The potential benefits and some challenges of an active learning course delivery to teach sustainability in geography and related…

  18. Determination of alternative pathway of complement activity in mouse serum using rabbit erythrocytes

    NARCIS (Netherlands)

    Dijk, H. van; Rademaker, P.M.; Willers, J.M.N

    1980-01-01

    Rabbit, mouse and sheep erythrocytes expressing different concentrations of membrane sialic acid were used to study possible modes of activation of the alternative complement (C) pathway in mouse, human and guinea pig serum. Mouse erythrocytes activated only human serum, whereas rabbit erythrocytes

  19. Dialyzer membranes: effect of surface area and chemical modification of cellulose on complement and platelet activation.

    Science.gov (United States)

    Mahiout, A; Meinhold, H; Kessel, M; Schulze, H; Baurmeister, U

    1987-04-01

    Using an ex vivo model, the effects of membrane composition and surface area on both the complement system (as reflected by plasma C3a levels) and platelets [as indicated by plasma concentrations of thromboxane B2 (TXB2) and platelet factor 4 (PF4)] were studied. In this model, polyacrylonitrile (PAN) was associated with less complement activation than cuprammonium cellulose (CC). A new "modified cellulose" (MC) membrane, in which a small number of the free hydroxyl groups on cellulose are substituted with a tertiary amino compound, was also associated with a low degree of complement activation, similar to that with PAN. However, the extent of hydroxyl group substitution in four MC membrane subtypes did not correlate with the reduction in complement activation. In studies using CC, the amount of generated C3a correlated with the membrane surface area, although the relationship was curvilinear. Plasma concentrations at the "dialyzer" outlet of TXB2 and PF4 were similar with CC, PAN, and MC. In studies with the MC subtypes, increasing the extent of hydroxyl group substitution paradoxically increased, albeit slightly, the amount of TXB2 generation. In studies with CC, a linear relationship between membrane surface area and TXB2 generation was found. The results suggest a dissociation between platelet and complement effects among different dialyzer membranes, and underline the importance of membrane surface area.

  20. Complement and Reactants of Acute Phase of Inflammation in the Processes of Functional Activity of Non-Specific Resistance and Immunoregulation.

    Science.gov (United States)

    Nazarov, Peter G.

    1999-10-01

    Complement system is a family comprising of 20 plasma and membrane proteins, acting in concord by cascade principle. The investigators display great interest to C4b-binding protein (C4bp) which is the main regulatory protein of complement system, regulating of C3 convertase activity in classical way of complement activation. The major regulatory function of C4bp is related to its interaction with activated form of the forth complement component, C4b. C4bp may also interact with one of pentraxins, serum amyloid P component (SAP) that inhibits complement-regulatory functions of C4bp. C4bp forms tight complexes with protein S and SAP. Pentraxin family (proteins with five-ray symmetry, such as C-reactive protein and SAP) became more numerous. Protein PTX3, synthesized by endothelial cells, macrophages and leukocytes, and considered to be local regulator of reaction of non-specific resistance in tissues; serum acute phase protein TSG-14; neuronal pentraxin - protein of cerebellum, hippocampus and brain cortex neurons, binding typoxin of snake venom; Narp (neuronal activity-regulated pentraxin) protein; apexin, acrosomal protein of spermatozoa; female hamster protein; pentraxin XL-PXN1 from Xenopus laevis - are all examples of new pentraxins. Pro-inflammatory cytokines, IL-1 and IL-6, may induce expression of pentraxin genes. Pentraxins are closely integrated not only to non-specific resistance, but to the system of immunoregulation and take part in its key events.

  1. Complement activation in the Parkinson's disease substantia nigra: an immunocytochemical study

    Directory of Open Access Journals (Sweden)

    Conant Stephanie B

    2006-10-01

    Full Text Available Abstract Background Inflammatory processes are increased in the Parkinson's disease (PD brain. The long-term use of nonsteroidal anti-inflammatory drugs has been associated, in retrospective studies, with decreased risk for PD, suggesting that inflammation may contribute to development of this disorder. The objective of this study was to determine the extent of complement activation, a major inflammatory mechanism, in PD. Methods Substantia nigra specimens from young normal subjects (n = 11–13, aged normal subjects (n = 24–28, and subjects with PD (n = 19–20, Alzheimer's disease (AD; n = 12–13, and dementia with Lewy bodies (DLB; n = 9 were stained for iC3b and C9, representing early- and late-stage complement activation, respectively. Numbers of iC3b+, C9+, and total melanized neurons in each section were counted in a blinded fashion. Nonparametric analyses were used to evaluate differences between groups and to evaluate correlations between complement staining, numbers of melanized neurons, and the duration of PD. Results Lewy bodies in both PD and DLB specimens stained for iC3b and C9. Staining was also prominent on melanized neurons. The percentage of iC3b+ neurons was significantly increased in PD vs. aged normal and AD specimens, and in young normal vs. aged normal specimens. C9 immunoreactivity was significantly increased in PD vs. AD specimens, but unlike iC3b, the increased C9 staining in PD and young normal specimens did not achieve statistical significance vs. aged normal specimens. iC3b and C9 staining in PD specimens was not correlated with the numbers of remaining melanized neurons, nor with the duration of PD. Conclusion Complement activation occurs on Lewy bodies and melanized neurons in the PD substantia nigra. Early complement activation (iC3b is increased on melanized neurons in PD vs. aged normal specimens, and late-stage complement activation (C9 also tends to increase. This latter finding suggests that complement

  2. Activity after Site-Directed Mutagenesis of CD59 on Complement-Mediated Cytolysis

    Institute of Scientific and Technical Information of China (English)

    Xinhong Zhu; Meihua Gao; Shurong Ren; Qiubo Wang; Cunzhi Lin

    2008-01-01

    CD59 may inhibit the cytolytic activity of complement by binding to C8/C9 and protect host cell membranes against homologous membrane attack complex (MAC). However, CD59 is widely overexpressed on tumor cells,which has been implicated in tumorigenesis. The active site of CD59 relative to MAC is still confused. As reported the MAC binding site is located in the vicinity of a hydrophobic groove on the membrane distal face of the protein centered around residue W40. Here two site-directed mutagenesis were performed by overlapping extension PCR to delete residue W40 site (Mutant 1, M1) or to change C39W40K41 to W39W40W41 (Mutant 2, M2). Then we constructed mutant CD59 eukaryotic expression system and investigated their biological function on CHO cells compared with wild-type CD59. Stable populations of CHO cells expressing recombinant proteins were screened by immunotechnique. After 30 passages culturing, proteins could be tested. Dye release assays suggest that M1CD59 loses the activity against complement, while M2CD59 increases the anti-complement activity slightly.Results indicate that W40 of human CD59 is important to its activity, and prohibition of this site may be a potential way to increase complement activity and to treat tumors.

  3. Cold activation of serum complement in patients with chronic hepatitis C: study on activating pathway and involvement of IgG.

    Directory of Open Access Journals (Sweden)

    Ishii Y

    2001-08-01

    Full Text Available It has been documented that the serum complement activities measured by hemolytic assay (CH50 are decreased after storage of sera at a low temperature in some patients with chronic hepatitis C. However, the mechanism of this phenomenon has not been identified yet. Here, we tried to elucidate factors involved in the cold activation of complement (CAC. To clarify what pathway is activated in CAC, we measured complement cleavage products after cold storage of sera. C4d increased significantly after 12 h-storage at cold temperatures in 5 CAC (+ sera compared with 5 CAC (- (P < 0.01 and 3 control sera (P < 0.05, while Bb did not increase in any of the groups. In order to determine whether IgG or IgG complex is necessary for CAC, 8 CAC (+ sera were incubated with Protein G Sepharose gel beads, and all of them retained hemolytic activities to some extent after cold storage. Column chromatography through Superose 6HR of CAC-positive serum identified the fractions containing molecules that induced CAC in normal serum, which were depleted by treatment with protein G Sepharose. In conclusion, CAC in hepatitis C seems to occur via a classical or lectin pathway, and the IgG complex produced in hepatitis C virus infection may be an important factor in inducing CAC, a common extrahepatic manifestation of hepatitis C.

  4. Discovery of Small Molecules for Fluorescent Detection of Complement Activation Product C3d.

    Science.gov (United States)

    Gorham, Ronald D; Nuñez, Vicente; Lin, Jung-Hsin; Rooijakkers, Suzan H M; Vullev, Valentine I; Morikis, Dimitrios

    2015-12-24

    Complement activation plays a major role in many acute and chronic inflammatory conditions. C3d, a terminal product of complement activation, remains covalently attached to cells and is an excellent biomarker of complement-mediated inflammation. We employed a virtual high-throughput screening protocol to identify molecules with predicted binding to complement C3d and with intrinsic fluorescence properties to enable detection. Pharmacophore models were developed based on known C3d-ligand interactions and information from computational analysis of structural and molecular dynamics data. Iterative pharmacophore-based virtual screening was performed to identify druglike molecules with physicochemical similarity to the natural C3d ligand CR2. Hits from the pharmacophore screens were docked to C3d and ranked based on predicted binding free energies. Top-ranked molecules were selected for experimental validation of binding affinity to C3d, using microscale thermophoresis, and for their suitability to become molecular imaging agents, using fluorescence spectroscopy. This work serves as a foundation for identifying additional fluorescent molecules with high-affinity for C3d that will subsequently be explored as noninvasive in vivo diagnostics of complement-mediated inflammation, for spatiotemporal monitoring of disease progression, and for targeting therapeutics to sites of inflammation.

  5. In-vitro activation of complement system by lactic acidosis in newborn and adults.

    Science.gov (United States)

    Hecke, F; Hoehn, T; Strauss, E; Obladen, M; Sonntag, J

    2001-01-01

    INTRODUCTION: Complement activation occurs secondary to a variety of external stimuli. Lactic acidosis has been previously shown to activate the complement factors C3a and C5a. In the present investigation we examined the differential effect of lactic acidosis on anaphylatoxin levels in cord and adult blood. Furthermore we aimed to determine if the entire complement cascade could be activated by lactic acidosis. METHODS: Cord and adult blood samples (n = 20 each) were collected and incubated for one hour in either untreated condition or with the addition of lactate in two concentrations (5.5 mmol/l vs. 22 mmol/l). Following incubation, levels of C3a, C5a and sC5b-9, and blood gas parameters were determined. RESULTS: Anaphylatoxin (C3a and C5a) and sC5b-9 levels increased with the addition of lactate in a dose-dependent manner in cord and adult blood (C3a: 1 h, 5.5 mmo/l, 22 mmol/l: 418/498/622 microg/l in cord blood; 1010/1056/1381 microg/l in adult blood, p<0,05; similar results were found for C5a and sC5b-9). CONCLUSION: Lactic acidosis leads to an activation of the entire complement system in neonates and in adults. This activation is dose-dependent and more pronounced in adults as compared to neonates. PMID:11324901

  6. Activation of complement by an IgG molecule without a genetic hinge.

    Science.gov (United States)

    Brekke, O H; Michaelsen, T E; Sandin, R; Sandlie, I

    1993-06-17

    The hinge region links the two Fab arms to the Fc portion of the IgG molecule. It mediates flexibility to the molecule and serves as a connecting structure between the two heavy chains. In addition it provides space between the Fab and Fc parts. All three properties have been proposed to be important for the ability of IgG to initiate complement activation leading to complement-mediated cell lysis (CML). Here we report the construction of a hinge-deleted mouse-human chimaeric IgG3 molecule with specificity for the hapten NIP (3-iodo-4-hydroxy-5-nitrophenacetyl), HM-1. HM-1 lacks the genetic hinge, but has an introduced cysteine between Ala 231 (EU numbering) and Pro 232 in the lower hinge encoded by the CH2 exon. The introduced cysteine forms a disulphide bond between the two heavy chains of the molecule. In CML, HM-1 shows a greater activity than IgG3 wild type. This is the first time an IgG molecule without a genetic hinge has been found to be active in CML. We conclude that the hinge functioning as a spacer is not a prerequisite for complement activation. Rather, its major role seems to be to connect the heavy chains to each other in the amino-terminal part of CH2. Because HM-1 is expected to have low Fab-Fc flexibility, this molecular feature is probably of no importance for complement activation.

  7. Spontaneous complement activation on human B cells results in localized membrane depolarization and the clustering of complement receptor type 2 and C3 fragments

    DEFF Research Database (Denmark)

    Løbner, Morten; Leslie, Robert G Q; Prodinger, Wolfgang M

    2009-01-01

    While our previous studies have demonstrated that complement activation induced by complement receptors type 2 (CR2/CD21) and 1 (CR1/CD35) results in C3-fragment deposition and membrane attack complex (MAC) formation in human B cells, the consequences of these events for B-cell functions remain...... requires activation of complement via the alternative pathway, as indicated by total inhibition upon neutralization of factor D, and is abrogated by combined blockade of CR1 and CR2, but not of either receptor alone. The membrane depolarization is not associated with the apoptosis of B cells, as examined...... by co-staining with APO-2.7 or by the TdT-mediated biotin-dUTP nick-end labelling (TUNEL) assay. Confocal microscopy revealed that depolarization and C3 deposition, unlike MAC deposition, are limited to restricted areas on the B-cell surface. Double staining revealed a close association between the C3...

  8. Complement activation by the amyloid proteins A beta peptide and beta 2-microglobulin

    DEFF Research Database (Denmark)

    Nybo, Mads; Nielsen, E H; Svehag, S E

    1999-01-01

    Complement activation (CA) has been reported to play a role in the pathogenesis of Alzheimer's disease (AD). To investigate whether CA may contribute to amyloidogenesis in general, the CA potential of different amyloid fibril proteins was tested. CA induced by A beta preparations containing solub...

  9. Factor B structure provides insights into activation of the central protease of the complement system

    NARCIS (Netherlands)

    Milder, F.J.; Gomes, L.; Schouten, A.; Janssen, B.J.C.; Huizinga, E.G.; Romijn, R.A.; Hemrika, W.; Roos, A; Daha, M.R.; Gros, P.

    2007-01-01

    Factor B is the central protease of the complement system of immune defense. Here, we present the crystal structure of human factor B at 2.3-A° resolution, which reveals how the five-domain proenzyme is kept securely inactive. The canonical activation helix of the Von Willebrand factor A (VWA) domai

  10. Fungal mediator tail subunits contain classical transcriptional activation domains.

    Science.gov (United States)

    Liu, Zhongle; Myers, Lawrence C

    2015-04-01

    Classical activation domains within DNA-bound eukaryotic transcription factors make weak interactions with coactivator complexes, such as Mediator, to stimulate transcription. How these interactions stimulate transcription, however, is unknown. The activation of reporter genes by artificial fusion of Mediator subunits to DNA binding domains that bind to their promoters has been cited as evidence that the primary role of activators is simply to recruit Mediator. We have identified potent classical transcriptional activation domains in the C termini of several tail module subunits of Saccharomyces cerevisiae, Candida albicans, and Candida dubliniensis Mediator, while their N-terminal domains are necessary and sufficient for their incorporation into Mediator but do not possess the ability to activate transcription when fused to a DNA binding domain. This suggests that Mediator fusion proteins actually are functioning in a manner similar to that of a classical DNA-bound activator rather than just recruiting Mediator. Our finding that deletion of the activation domains of S. cerevisiae Med2 and Med3, as well as C. dubliniensis Tlo1 (a Med2 ortholog), impairs the induction of certain genes shows these domains function at native promoters. Activation domains within coactivators are likely an important feature of these complexes and one that may have been uniquely leveraged by a common fungal pathogen.

  11. Binding and activation of human and mouse complement by Cryptosporidium parvum (Apicomplexa) and susceptibility of C1q- and MBL-deficient mice to infection.

    Science.gov (United States)

    Petry, Franz; Jakobi, Vera; Wagner, Swen; Tessema, Tesfaye Sisay; Thiel, Steffen; Loos, Michael

    2008-07-01

    Cryptosporidium parvum is a protozoan parasite (Apicomplexa) that causes gastrointestinal disease in animals and humans. Whereas immunocompetent hosts can limit the infection within 1 or 2 weeks, immunocompromised individuals develop a chronic, life-threatening disease. The importance of the adaptive cellular immune response, with CD4+ T-lymphocytes being the major players, has been clearly demonstrated. Several non-adaptive immune mechanisms have been suggested to contribute to the host defence, such as interferon-gamma (IFN-gamma) from NK cells, certain chemokines, beta-defensins and pro-inflammatory cytokines, but the influence of the complement systems has been less well studied. We analysed the in vitro binding and activation of the human and mouse complement systems and tested the susceptibility to infection in complement-deficient mouse strains. We found that C. parvum can activate both the classical and lectin pathways, leading to the deposition of C3b on the parasite. Using real-time PCR, parasite development could be demonstrated in adult mice lacking mannan-binding lectin (MBL-A/C-/-) but not in mice lacking complement factor C1q (C1qA-/-) or in wild type C57BL/6 mice. The contribution of the complement system and the lectin pathway in particular to the host defence against cryptosporidiosis may become apparent in situations of immunodeficiency such as HIV infections or in early childhood.

  12. Targeting complement activation in brain-dead donors improves renal function after transplantation.

    Science.gov (United States)

    Damman, Jeffrey; Hoeger, Simone; Boneschansker, Leo; Theruvath, Ashok; Waldherr, Ruediger; Leuvenink, Henri G; Ploeg, Rutger J; Yard, Benito A; Seelen, Marc A

    2011-05-01

    Kidneys recovered from brain-dead donors have inferior outcomes after transplantation compared to kidneys from living donors. Since complement activation plays an important role in renal transplant related injury, targeting complement activation in brain-dead donors might improve renal function after transplantation. Brain death (BD) was induced in Fisher rats by inflation of an epidurally placed balloon catheter and ventilated for 6h. BD animals were treated with soluble complement receptor 1 (sCR1) 1h before or 1h after BD. Kidney transplantation was performed and 7 days after transplantation animals were sacrificed. Plasma creatinine and urea were measured at days 0, 1, 3, 5 and 7 after transplantation. Renal function was significantly better at day 1 after transplantation in recipients receiving a sCR1 pre-treated donor kidney compared to recipients of a non-treated donor graft. Also treatment with sCR1, 1h after the diagnosis of BD, resulted in a better renal function after transplantation. Gene expression of IL-6, IL-1beta and TGF-beta were significantly lower in renal allografts recovered from treated donors. This study shows that targeting complement activation, during BD in the donor, leads to an improved renal function after transplantation in the recipient.

  13. Down-regulation of Stathmin Is Required for the Phenotypic Changes and Classical Activation of Macrophages.

    Science.gov (United States)

    Xu, Kewei; Harrison, Rene E

    2015-07-31

    Macrophages are important cells of innate immunity with specialized capacity for recognition and elimination of pathogens and presentation of antigens to lymphocytes for adaptive immunity. Macrophages become activated upon exposure to pro-inflammatory cytokines and pathogenic stimuli. Classical activation of macrophages with interferon-γ (IFNγ) and lipopolysaccharide (LPS) triggers a wide range of signaling events and morphological changes to induce the immune response. Our previous microtubule (MT) proteomic work revealed that the stathmin association with MTs is considerably reduced in activated macrophages, which contain significantly more stabilized MTs. Here, we show that there is a global decrease in stathmin levels, an MT catastrophe protein, in activated macrophages using both immunoblotting and immunofluorescent microscopy. This is an LPS-specific response that induces proteasome-mediated degradation of stathmin. We explored the functions of stathmin down-regulation in activated macrophages by generating a stable cell line overexpressing stathmin-GFP. We show that stathmin-GFP overexpression impacts MT stability, impairs cell spreading, and reduces activation-associated phenotypes. Furthermore, overexpressing stathmin reduces complement receptor 3-mediated phagocytosis and cellular activation, implicating a pivotal inhibitory role for stathmin in classically activated macrophages.

  14. Activity patterns in latissimus dorsi and sternocleidomastoid in classical singers.

    Science.gov (United States)

    Watson, Alan H D; Williams, Caitlin; James, Buddug V

    2012-05-01

    The aim of this study was to investigate and compare the roles of the accessory respiratory muscles, latissimus dorsi (LD), and sternocleidomastoid, in classical singing. Electromyography was used to record the activity of these muscles in six classically trained female singers carrying out a number of singing and nonsinging tasks. Movements of the chest and abdominal walls were monitored simultaneously using inductive plethysmography, and the sound of the phonations was recorded. In normal breathing, LD is active transiently during very deep inhalations and in inhalation against resistance. During exhalation it becomes active again as residual capacity is approached or when air is expelled with great force. Sternocleidomastoid (SCM) supports inhalation when lung volume nears 100% vital capacity or when this is very rapid. All singers engaged LD in supported singing where it was associated with maintaining an expanded thorax. In coloratura singing, pulses of activity of increasing amplitude were often seen in LD toward the end of the breath. These were synchronized with each note. During a short phrase typical of the end of an aria, which was sung at full volume with the projected voice, both LD and SCM were active simultaneously. Spectral analysis of muscle activity demonstrated that in some singers, activity in LD and more rarely SCM, fluctuated in phase with vibrato. LD appears to play a significant role in maintaining chest expansion and the dynamic processes underlying vibrato and coloratura singing in classically trained singers. Copyright © 2012 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  15. Complement activation pathways associated with islet cell surface antibody (ICSA derived from child patients with insulin-dependent diabetes mellitus (IDDM.

    Directory of Open Access Journals (Sweden)

    Okada,Soji

    1991-06-01

    Full Text Available We studied the pathways of complement activation associated with the islet cell surface antibody (ICSA obtained from sera of 7 patients (age less than 15 years with insulin dependent diabetes mellitus (IDDM. The target cells were 51CR labelled rat islet cells and the complement source was human AB serum. Complement-dependent antibody mediated cytotoxicity (CAMC activity was obtained using the percentage of cytotoxicity. CAMC activity of untreated sera was significantly inhibited by treating with EGTA or EDTA (p less than 0.001. The CAMC activity of EDTA-treated sera was significantly lower than that of EGTA-treated sera (p less than 0.001. In the inactivated human AB serum, it was lower than that of EGTA-treated sera (p less than 0.05, but not different from that of EDTA-treated sera. These results show that the complement activation associated with ICSA in patients occurred not only via the classical pathway but also via the alternative pathway.

  16. Complement in Lupus Nephritis: New Perspectives

    Science.gov (United States)

    Bao, Lihua; Cunningham, Patrick N.; Quigg, Richard J.

    2015-01-01

    Background Systemic lupus erythematosus (SLE) is an autoimmune disorder caused by loss of tolerance to self-antigens, the production of autoantibodies and deposition of complement-fixing immune complexes (ICs) in injured tissues. SLE is characterized by a wide range of clinical manifestations and targeted organs, with lupus nephritis being one of the most serious complications. The complement system consists of three pathways and is tightly controlled by a set of regulatory proteins to prevent injudicious complement activation on host tissue. The involvement of the complement system in the pathogenesis of SLE is well accepted; yet, its exact role is still not clear. Summary Complement plays dual roles in the pathogenesis of SLE. On the one hand, the complement system appears to have protective features in that hereditary homozygous deficiencies of classical pathway components, such as C1q and C4, are associated with an increased risk for SLE. On the other hand, IC-mediated activation of complement in affected tissues is clearly evident in both experimental and human SLE along with pathological features that are logical consequences of complement activation. Studies in genetically altered mice have shown that lack of complement inhibitors, such as complement factor H (CFH) or decay-accelerating factor (DAF) accelerates the development of experimental lupus nephritis, while treatment with recombinant protein inhibitors, such as Crry-Ig, CR2-Crry, CR2-DAF and CR2-CFH, ameliorates the disease development. Complement-targeted drugs, including soluble complement receptor 1 (TP10), C1 esterase inhibitor and a monoclonal anti-C5 antibody (eculizumab), have been shown to inhibit complement safely, and are now being investigated in a variety of clinical conditions. Key Messages SLE is an autoimmune disorder which targets multiple systems. Complement is centrally involved and plays dual roles in the pathogenesis of SLE. Studies from experimental lupus models and clinical

  17. Fcγ and Complement Receptors and Complement Proteins in Neutrophil Activation in Rheumatoid Arthritis: Contribution to Pathogenesis and Progression and Modulation by Natural Products

    Directory of Open Access Journals (Sweden)

    Adriana Balbina Paoliello-Paschoalato

    2015-01-01

    Full Text Available Rheumatoid arthritis (RA is a highly disabling disease that affects all structures of the joint and significantly impacts on morbidity and mortality in RA patients. RA is characterized by persistent inflammation of the synovial membrane lining the joint associated with infiltration of immune cells. Eighty to 90% of the leukocytes infiltrating the synovia are neutrophils. The specific role that neutrophils play in the onset of RA is not clear, but recent studies have evidenced that they have an important participation in joint damage and disease progression through the release of proteolytic enzymes, reactive oxygen species (ROS, cytokines, and neutrophil extracellular traps, in particular during frustrated phagocytosis of immune complexes (ICs. In addition, the local and systemic activation of the complement system contributes to the pathogenesis of RA and other IC-mediated diseases. This review discusses (i the participation of Fcγ and complement receptors in mediating the effector functions of neutrophils in RA; (ii the contribution of the complement system and ROS-dependent and ROS-independent mechanisms to joint damage in RA; and (iii the use of plant extracts, dietary compounds, and isolated natural compounds in the treatment of RA, focusing on modulation of the effector functions of neutrophils and the complement system activity and/or activation.

  18. Linear systems analysis of activating processes of complement system as a defense mechanism.

    Science.gov (United States)

    Hirayama, H; Yoshii, K; Ojima, H; Kawai, N; Gotoh, S; Fukuyama, Y

    1996-01-01

    The complement system is an important element of the host defense mechanism, although its kinetics and characteristics as a system are still unclear. We have investigated its temporal changes and system properties from the view point of system engineering. The temporal changes of sequential activating processes of the system were expressed by 26 non-linear differential equations using reported values of rate constants and serum concentration for each component. The intermediate products in the activating processes increased parabolically while the membrane attack component as the final product, increased linearly. The little change in inactive precursors afforded validity for system linearization. Linear systems analysis revealed that the system which was insensitive to the changes in rate constants was unstable. The system became stable when the feed-back input from the final product was set to operate on the first step of the activating processes. Seven uncontrollable variables were insensitive to changes in rate constants or system optimization that minimized the changes in concentrations of components in the complement system. The singular values of the complement system were reduced and the impulse responses of the system were improved when the system was optimized. When stronger minimization was imposed on the changes of concentration of the components in the complement system, the singular values were reduced more, the magnitude of the impulse responses was depressed further and the responses terminated earlier than those when the elements in the weighting matrix of concentration of the components were set to be unity. By this potent minimization, the influences of changes in rate constants on the singular values were diminished. The present theoretical analysis is presented to evaluate the ability of defense mechanism of complement system.

  19. Core shell methyl methacrylate chitosan nanoparticles: In vitro mucoadhesion and complement activation

    Directory of Open Access Journals (Sweden)

    F Atyabi

    2011-10-01

    Full Text Available Background and the purpose of the study: Studies show that chitosan nanoparticles increase mucoadhesivity and penetration of large molecules across mucosal surface. The aim of the present study was to investigate the use of thiolated chitosan in the development of polysaccharide-coated nanoparticles in order to confer specific functionality to the system. Methods: Methyl methacrylate nanoparticles were coated with thiolated chitosan using a radical polymerization method. Thiolation was carried out using glutathione (GSH to improve mucoadhesivity and permeation enhancing properties of chitosan. Mucoadhesion studies were carried out by calculating the amount of mucin adsorbed on nanoparticles in a specific period of time. Complement consumption was assessed in human serum (HS by measurement of the hemolytic capacity of the complement system after contact with nanoparticles.   Results:   The FT-IR and 1HNMR spectra both confirmed the synthesis and showed the conjugation of thiolated chitosan to methyl methacrylate (MMA homopolymer. Nanoparticles were spherical having a mean diameter within the range of about 334-650 nm and their positive zeta potential values indicated the presence of the cationic polysaccharide at the nanoparticle surface. Increasing the amount of thiolated chitosan led to mucoadhesivity and complement activation. However there was not dose dependent correlation between these phenomenons and the absence of thiolated chitosan led to particles with larger size, and without ability to activate complement process. Major conclusion: It can be concluded that nanoparticles could be used for the mucosal delivery of peptides and proteins. Results show that the thiolated chitosan had higher mucoadhesion and complement activation than unmodified chitosan.

  20. Hepatic inflammation mediated by hepatitis C virus core protein is ameliorated by blocking complement activation

    Directory of Open Access Journals (Sweden)

    Hsu Chen-Ming

    2009-08-01

    Full Text Available Abstract Background The pathogenesis of inflammation and fibrosis in chronic hepatitis C virus (HCV infection remains unclear. Transgenic mice with constitutive HCV core over-expression display steatosis only. While the reasons for this are unclear, it may be important that core protein production in these models begins during gestation, in contrast to human hepatitis C virus infection, which occurs post-natally and typically in adults. AIMS: To more realistically model the effect of core protein production in the adult liver, we developed a mouse with conditional expression of HCV core and examined the effect of core protein production in the adult liver. Methods Liver biopsy samples from transgenic mice with tetracycline(tet-regulated conditional core protein expression were evaluated immunohistologically. Microarray analysis of HCV core transgenic mice with steatohepatitis pointed to a role of the complement pathway. This was further explored by blocking complement activation by in vivo administration of CD55 (decay accelerating factor for complement, which inhibits activation of C3. Results Transgenic mice exhibited low, intermediate, or high HCV core protein expression when fed a permissive diet of standard chow. Aside from hepatic steatosis, hepatic inflammation and fibrosis were seen in mice with intermediate levels of core protein. Microarray analyses of inflamed liver demonstrated activation of both the complement (C3 up-regulation and coagulation pathways (fibrinogen B up-regulation. Administration of CD55 reduced hepatic inflammation. Conclusion Transgenic mice that conditionally express intermediate HCV core protein develop inflammation, steatosis, and fibrosis. These effects mediated by HCV core are reduced by administration of CD55, a regulator of the complement pathway. The model may be valuable in investigating the pathogenesis of liver inflammation in chronic hepatitis C.

  1. in vitro activation of complement and contact system by lactic acidosis

    Directory of Open Access Journals (Sweden)

    J. Sonntag

    1998-01-01

    Full Text Available The activation of complement and contact systems occurs in reperfusion injuries with initial tissue hypoxia, and lactic acidosis such as mycardial infarction and birth asphyxia. The aim of our experiment was the formal proof of activation by sole lactic acidosis. Lactic acid was added to blood and plasma samples from 10 healthy volunteers. C5a and factor XIIa were measured by EIA after incubation at 37°C for 1 h. Both concentrations increased (P<0.0001 by Friedman analysis in blood and plasma samples with increasing amount of added lactic acid. Lactic acidosis can activate C5 from the complement system and factor XII from the contact system directly, even in the absence of cellular components.

  2. In vitro activation of complement and contact system by lactic acidosis.

    Science.gov (United States)

    Sonntag, J; Emeis, M; Strauss, E; Obladen, M

    1998-01-01

    The activation of complement and contact systems occurs in reperfusion injuries with initial tissue hypoxia, and lactic acidosis such as mycardial infarction and birth asphyxia. The aim of our experiment was the formal proof of activation by sole lactic acidosis. Lactic acid was added to blood and plasma samples from 10 healthy volunteers. C5a and factor XIIa were measured by EIA after incubation at 37 degrees C for 1 h. Both concentrations increased (P < 0.0001 by Friedman analysis) in blood and plasma samples with increasing amount of added lactic acid. Lactic acidosis can activate C5 from the complement system and factor XII from the contact system directly, even in the absence of cellular components. PMID:9839699

  3. Complement C1q activates tumor suppressor WWOX to induce apoptosis in prostate cancer cells.

    Directory of Open Access Journals (Sweden)

    Qunying Hong

    Full Text Available BACKGROUND: Tissue exudates contain low levels of serum complement proteins, and their regulatory effects on prostate cancer progression are largely unknown. We examined specific serum complement components in coordinating the activation of tumor suppressors p53 and WWOX (also named FOR or WOX1 and kinases ERK, JNK1 and STAT3 in human prostate DU145 cells. METHODOLOGY/PRINCIPAL FINDINGS: DU145 cells were cultured overnight in 1% normal human serum, or in human serum depleted of an indicated complement protein. Under complement C1q- or C6-free conditions, WOX1 and ERK were mainly present in the cytoplasm without phosphorylation, whereas phosphorylated JNK1 was greatly accumulated in the nuclei. Exogenous C1q rapidly restored the WOX1 activation (with Tyr33 phosphorylation in less than 2 hr. Without serum complement C9, p53 became activated, and hyaluronan (HA reversed the effect. Under C6-free conditions, HA induced activation of STAT3, an enhancer of metastasis. Notably, exogenous C1q significantly induced apoptosis of WOX1-overexpressing DU145 cells, but not vehicle-expressing cells. A dominant negative and Y33R mutant of WOX1 blocked the apoptotic effect. C1q did not enhance p53-mediated apoptosis. By total internal reflection fluorescence (TIRF microscopy, it was determined that C1q destabilized adherence of WOX1-expressing DU145 cells by partial detaching and inducing formation of clustered microvilli for focal adhesion particularly in between cells. These cells then underwent shrinkage, membrane blebbing and death. Remarkably, as determined by immunostaining, benign prostatic hyperplasia and prostate cancer were shown to have a significantly reduced expression of tissue C1q, compared to age-matched normal prostate tissues. CONCLUSIONS/SIGNIFICANCE: We conclude that complement C1q may induce apoptosis of prostate cancer cells by activating WOX1 and destabilizing cell adhesion. Downregulation of C1q enhances prostate hyperplasia and cancerous

  4. Complement activation by in vivo neonatal and in vitro extracorporeal membrane oxygenation.

    Science.gov (United States)

    Graulich, Johannes; Sonntag, Joseph; Marcinkowski, Monika; Bauer, Karl; Kössel, Hans; Bührer, Christoph; Obladen, Michael; Versmold, Hans T

    2002-01-01

    Complment activation during extracorporeal membrane oxygenation (ECMO) in newborns can be caused by both the underlying disease processes and by blood contact with the ECMO circuit. We investigated the relative importance of these mechanisms by measuring C3a, C5a and sC5b-9 before, during and after neonatal ECMO in six consecutive newborn patients using enzyme-linked immunoassay. In addition complement activation during in vitro ECMO with repeated flow of the same blood volume was measured using blood from healthy adult donors. C3a increased significantly in vivo after 1 h (from 1035+/-193 to 1865+/-419 microg/l) and in vitro ECMO (from 314+/-75 to 1962+/-1062 microg/l). C5a increased during ECMO without significant differences between in vivo and in vitro activation. In neonatal patients, sC5b-9 rose faster than in vitro, but the rapid increase was also significant for in vitro experiments (in vivo: from 328+/-63 to 1623+/-387 microg/l after 2 h; and in vitro: from 78+/-32 to 453+/-179 microg/l after 8 h). After this initial peak at 1-2 h, complement activation decreased gradually until 2-3 days after the initiation of ECMO. We conclude that in newborns the rapid activation of the complement system after the start of ECMO is predominantly caused by contact with artificial surfaces rather than the patient's underlying disease. PMID:12061426

  5. Impaired NK Cell Activation and Chemotaxis toward Dendritic Cells Exposed to Complement-Opsonized HIV-1

    Science.gov (United States)

    Ellegård, Rada; Crisci, Elisa; Andersson, Jonas; Shankar, Esaki M.; Nyström, Sofia; Hinkula, Jorma

    2015-01-01

    Mucosa resident dendritic cells (DCs) may represent one of the first immune cells that HIV-1 encounters during sexual transmission. The virions in body fluids can be opsonized with complement factors because of HIV-mediated triggering of the complement cascade, and this appears to influence numerous aspects of the immune defense targeting the virus. One key attribute of host defense is the ability to attract immune cells to the site of infection. In this study, we investigated whether the opsonization of HIV with complement (C-HIV) or a mixture of complement and Abs (CI-HIV) affected the cytokine and chemokine responses generated by DCs, as well as their ability to attract other immune cells. We found that the expression levels of CXCL8, CXCL10, CCL3, and CCL17 were lowered after exposure to either C-HIV or CI-HIV relative to free HIV (F-HIV). DCs exposed to F-HIV induced higher cell migration, consisting mainly of NK cells, compared with opsonized virus, and the chemotaxis of NK cells was dependent on CCL3 and CXCL10. NK cell exposure to supernatants derived from HIV-exposed DCs showed that F-HIV induced phenotypic activation (e.g., increased levels of TIM3, CD69, and CD25) and effector function (e.g., production of IFNγ and killing of target cells) in NK cells, whereas C-HIV and CI-HIV did not. The impairment of NK cell recruitment by DCs exposed to complement-opsonized HIV and the lack of NK activation may contribute to the failure of innate immune responses to control HIV at the site of initial mucosa infection. PMID:26157174

  6. Complement activation by in vivo neonatal and in vitro extracorporeal membrane oxygenation

    Directory of Open Access Journals (Sweden)

    Johannes Graulich

    2002-01-01

    Full Text Available Complement activation during extracorporeal membrane oxygenation (ECMO in newborns can be caused by both the underlying disease processes and by blood contact with the ECMO circuit. We investigated the relative importance of these mechanisms by measuring C3a, C5a and sC5b-9 before, during and after neonatal ECMO in six consecutive newborn patients using enzyme-linked immunoassay. In addition complement activation during in vitro ECMO with repeated flow of the same blood volume was measured using blood from healthy adult donors. C3a increased significantly in vivo after 1 h (from 1035 ± 193 to 1865 ± 419 μg/l and in vitro ECMO (from 314 ± 75 to 1962 ± 1062 μg/l. C5a increased during ECMO without significant differences between in vivo and in vitro activation. In neonatal patients, sC5b-9 rose faster than in vitro, but the rapid increase was also significant for in vitro experiments (in vivo: from 328 ± 63 to 1623 ± 387 μg/l after 2 h; and in vitro: from 78 ± 32 to 453 ± 179 μg/l after 8 h. After this initial peak at 1-2 h, complement activation decreased gradually until 2-3 days after the initiation of ECMO. We conclude that in newborns the rapid activation of the complement system after the start of ECMO is predominantly caused by contact with artificial surfaces rather than the patient's underlying disease.

  7. Different activation patterns in the plasma kallikrein-kinin and complement systems during coronary bypass surgery.

    Science.gov (United States)

    Kongsgaard, U E; Smith-Erichsen, N; Geiran, O; Amundsen, E; Mollnes, T E; Garred, P

    1989-07-01

    Components of the plasma kallikrein-kinin and complement systems were determined in patients undergoing open heart surgery with cardiopulmonary bypass. Spontaneous kallikrein activity (KK), plasma prekallikrein (PKK), functional kallikrein inhibition capacity (KKI), C3 activation products (C3-act), and the terminal complement complex (TCC) were measured. A marked, transitory increase in KK and a decrease in PKK were found prior to cardiopulmonary bypass just after heparin injection. An additional decline in PKK and KKI during bypass with a return to near control levels in the postoperative period was observed. C3-act increased in all patients during bypass, reaching a peak value at wound closure. The TCC concentration also increased significantly during cardiopulmonary bypass, returned to control levels in the early postoperative period, and then increased again in the late postoperative period. It is concluded that activation of the kallikrein-kinin system started after injection of heparin, prior to cardiopulmonary bypass. Activation of both the initial and the terminal complement cascade, however, started only after onset of cardiopulmonary bypass.

  8. Domain complementation studies reveal residues critical for the activity of the mannitol permease from Escherichia coli.

    Science.gov (United States)

    Vos, Erwin P P; ter Horst, Ramon; Poolman, Bert; Broos, Jaap

    2009-02-01

    This paper presents domain complementation studies in the mannitol transporter, EIImtl, from Escherichia coli. EIImtl is responsible for the transport and concomitant phosphorylation of mannitol over the cytoplasmic membrane. By using tryptophan-less EIImtl as a basis, each of the four phenylalanines located in the cytoplasmic loop between putative transmembrane helices II and III in the membrane-embedded C domain were replaced by tryptophan, yielding the mutants W97, W114, W126, and W133. Except for W97, these single-tryptophan mutants exhibited a high, wild-type-like, binding affinity for mannitol. Of the four mutants, only W114 showed a high mannitol phosphorylation activity. EIImtl is functional as a dimer and the effect of these mutations on the oligomeric activity was investigated via heterodimer formation (C/C domain complementation studies). The low phosphorylation activities of W126 and W133 could be increased 7-28 fold by forming heterodimers with either the C domain of W97 (IICmtlW97) or the inactive EIImtl mutant G196D. W126 and W133, on the other hand, did not complement each other. This study points towards a role of positions 97, 126 and 133 in the oligomeric activation of EIImtl. The involvement of specific residue positions in the oligomeric functioning of a sugar-translocating EII protein has not been presented before.

  9. Effective Neutrophil Phagocytosis of Aspergillus fumigatus Is Mediated by Classical Pathway Complement Activation

    NARCIS (Netherlands)

    Braem, Steven G E; Rooijakkers, Suzan H M; van Kessel, Kok P M; de Cock, Hans; Wosten, Han; van Strijp, Jos A G; Haas, Pieter-Jan A

    2015-01-01

    Aspergillus fumigatus is an important airborne fungal pathogen and a major cause of invasive fungal infections. Susceptible individuals become infected via the inhalation of dormant conidia. If the immune system fails to clear these conidia, they will swell, germinate and grow into large hyphal stru

  10. A novel method for direct measurement of complement convertases activity in human serum

    NARCIS (Netherlands)

    Blom, A.M.; Volokhina, E.B.; Fransson, V.; Stromberg, P.; Berghard, L.; Viktorelius, M.; Mollnes, T.E.; Lopez-Trascasa, M.; Heuvel, B. van den; Goodship, T.H.; Marchbank, K.J.; Okroj, M.

    2014-01-01

    Complement convertases are enzymatic complexes that play a central role in sustaining and amplification of the complement cascade. Impairment of complement function leads directly or indirectly to pathological conditions, including higher infection rate, kidney diseases, autoimmune- or neurodegenera

  11. Complement Activation: An Emerging Player in the Pathogenesis of Cardiovascular Disease

    OpenAIRE

    2012-01-01

    A wealth of evidence indicates a fundamental role for inflammation in the pathogenesis of cardiovascular disease (CVD), contributing to the development and progression of atherosclerotic lesion formation, plaque rupture, and thrombosis. An increasing body of evidence supports a functional role for complement activation in the pathogenesis of CVD through pleiotropic effects on endothelial and haematopoietic cell function and haemostasis. Prospective and case control studies have reported stron...

  12. Complement activation and liver impairment in trichloroethylene-sensitized BALB/c mice.

    Science.gov (United States)

    Zhang, Jiaxiang; Zha, Wansheng; Wang, Feng; Jiang, Tao; Xu, Shuhai; Yu, Junfeng; Zhou, Chengfan; Shen, Tong; Wu, Changhao; Zhu, Qixing

    2013-01-01

    Our recent studies have shown that trichloroethylene (TCE) was able to induce multisystem injuries in the form of occupational medicamentosa-like dermatitis, including skin, kidney, and liver damages. However, the role of complement activation in the immune-mediated liver injury is not known. This study examined the role of complement activation in the liver injury in a mouse model of TCE-induced sensitization. Treatment of female BALB/c mice with TCE under specific dosing protocols resulted in skin inflammation and sensitization. Skin edema and erythema occurred in TCE-sensitized groups. Trichloroethylene sensitization produced liver histopathological lesions, increased serum alanine aminotransferase, aspartate transaminase activities, and the relative liver weight. The concentrations of serum complement components C3a-desArg, C5a-desArg, and C5b-9 were significantly increased in 24-hour, 48-hour, and 72-hour sensitization-positive groups treated with TCE and peaked in the 72-hour sensitization-positive group. Depositions of C3a, C5a, and C5b-9 into the liver tissue were also revealed by immunohistochemistry. Immunofluorescence further verified high C5b-9 expression in 24-hour, 48-hour, and 72-hour sensitization-positive groups in response to TCE treatment. Reverse transcription-polymerase chain reaction detected C3 messenger RNA expression in the liver, and this was significantly increased in 24-hour and 48-hour sensitization-positive groups with a transient reduction at 72 hours. These results provide the first experimental evidence that complement activation may play a key role in the generation and progression of immune-mediated hepatic injury by exposure to TCE.

  13. Inhibition of complement activation by water-soluble polysaccharides of some far-eastern brown seaweeds.

    Science.gov (United States)

    Zvyagintseva, T N; Shevchenko, N M; Nazarova, I V; Scobun, A S; Luk'yanov, P A; Elyakova, L A

    2000-07-01

    Fucoidans and laminarans from Laminaria cichorioides, Laminaria japonica, Fucus evanescens, laminaran from Laminaria gurjanovae, other beta-D-glucans (translam, pustulan and zymosan) and lambda-carrageenan from Chondrus armatus were used to study the effect of water-soluble polysaccharides from seaweeds on the alternative pathway of complement (APC). beta-D-Glucans and fucoidans under study differed appreciably from each other by structural characteristics, and also by degree of purification. beta-D-glucans, on ability to bind complement, ranked in a line according to a degree of their purification. Highly purified beta-D-glucans under study did not reveal an ability to bind complement. The fucoidans were divided conventionally into three groups according to their action on APC. Highly sulfated alpha-L-fucan from L. cichorioides with the greatest activity toward APC and caused 50% inhibition of reaction of activation (RA) of APC in a concentration of 0.5-0.7 mg/ml. Opposite 50% of inhibition of lysis of erythrocytes by sulfated heterogeneous fucoidan from L. japonica was achieved with 20 mg/ml. All other fucoidans and lambda-carrageenan have activity at 6-10 mg/ml concentration. Decreasing the sulfate content from 36% up to 9% in sample fucoidans under study was not reflected practically in the 50% inhibition concentration. Apparently, the degree of sulfating of fucoidans did not influence their action on APC. But the positive influence of fucose in structure of polysaccharide was obvious.

  14. Early complement activation increases in the brain in some aged normal subjects.

    Science.gov (United States)

    Loeffler, David A; Camp, Dianne M; Schonberger, Michael B; Singer, Daniel J; LeWitt, Peter A

    2004-09-01

    Complement activation is increased in Alzheimer's disease (AD) and may contribute to the development and progression of this disorder. To compare early complement activation between normal and AD brain specimens, C4d and iC3b concentrations were measured in hippocampus, entorhinal cortex, temporal cortex, parietal cortex, and cerebellum from aged normal and AD subjects n=10-14 for both), and in hippocampus and entorhinal cortex from younger normal subjects (n=5-6). C4d and iC3b levels increased 2.3- to 4.6-fold in AD versus aged normal specimens (all P hippocampus or entorhinal cortex. However, the concentrations of these proteins were markedly increased in several aged normal specimens. Normal subject age was moderately associated with both C4d (r=0.49) and iC3b (r=0.53) concentrations in the hippocampus. Increased brain complement activation in some elderly individuals may promote the subsequent development of AD.

  15. Identification and characterization of serum complement activity in the American crocodile (Crocodylus acutus).

    Science.gov (United States)

    Merchant, Mark; McFatter, Justin; Mead, Stephanie; McAdon, Charles; Wasilewski, Joe

    2010-02-15

    Incubation of unsensitized sheep red blood cells with serum from the American crocodile (Crocodylus acutus) resulted in a concentration-dependent hemolysis. The hemolytic activity was heat-sensitive, and inhibited by EDTA in a concentration-dependent manner. The EDTA-inhibited SRBC hemolysis could be restored by the addition of excess Ca2+ or Mg2+, but not Ba2+ or Cu2+, revealing the specificity of this activity for these two divalent cations. The hemolytic activity of crocodile serum was titer-dependent, with 329 microL producing 50% of maximal SRBC hemolysis. The complement activity was also temperature-dependent, with decreased activity at lower temperatures (5-15 degrees C) and maximal activity occurred at 30-40 degrees C. The hemolysis occurred relatively slowly, with near zero activity after 10 min, 40% of activity observed within 15 min of exposure to SRBCs, and maximal activity at 30 min.

  16. Alternative complement pathway and factor B activities in rats with altered blood levels of thyroid hormone

    Energy Technology Data Exchange (ETDEWEB)

    Bitencourt, C.S. [Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Duarte, C.G.; Azzolini, A.E.C.S.; Assis-Pandochi, A.I. [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil)

    2012-03-02

    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.

  17. Alternative complement pathway and factor B activities in rats with altered blood levels of thyroid hormone

    Directory of Open Access Journals (Sweden)

    C.S. Bitencourt

    2012-03-01

    Full Text Available 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.

  18. Characterization of serum complement activity of saltwater (Crocodylus porosus) and freshwater (Crocodylus johnstoni) crocodiles.

    Science.gov (United States)

    Merchant, Mark; Britton, Adam

    2006-04-01

    We employed a spectroscopic assay, based on the hemolysis of sheep red blood cells (SRBCs), to assess the innate immune function of saltwater and freshwater crocodiles in vitro. Incubation of serum from freshwater and saltwater crocodiles with SRBCs resulted in concentration-dependent increases in SRBC hemolysis. The hemolytic activity occurred rapidly, with detectable activity within 2 min and maximum activity at 20 min. These activities, in both crocodilian species, were heat sensitive, unaffected by 20 mM methylamine, and completely inhibited by low concentrations of EDTA, suggesting that the alternative serum complement cascade is responsible for the observed effects. The hemolytic activities of the sera were inhibited by other chelators of divalent metal ions, such as phosphate and citrate. The inhibition of SRBC hemolysis by EDTA could be completely restored by the addition of 10 mM Ca2+ or Mg2+, but not Ba2+, Cu2+ or Fe2+, indicating specificity for these metal ions. The serum complement activities of both crocodilians were temperature-dependent, with peak activities occurring at 25-30 degrees C and reduced activities below 25 degrees C and above 35 degrees C.

  19. Complement activation and its prognostic role in post-cardiac arrest patients

    DEFF Research Database (Denmark)

    Jenei, Z M; Zima, E; Csuka, D;

    2014-01-01

    that the extent of complement activation might be a reliable predictor of mortality in this population. Forty-six comatose cardiac arrest patients were enrolled into our prospective cohort study, conducted in a tertiary care university clinic. All subjects were cooled to 32-34 °C body temperature for 24 h...... and then allowed to rewarm to normothermia. All patients underwent diagnostic coronary angiography. On admission, at 6 and 24 h, blood samples were taken from the arterial catheter. In these, complement products (C3a, C3, C4d, C4, SC5b9 and Bb) were measured by ELISA in blood samples. Patients were followed up...... for 30 days; 22 patients (47.8%) died by the end of this period. We observed that complement activation (determined as the C3a to C3 ratio) was higher in non-survivors than in survivors at each time point. In the multivariate Cox regression analysis, the C3a/C3 ratio determined 24 h after the initiation...

  20. Optimizing complement-activating antibody-based cancer immunotherapy: a feasible strategy?

    Directory of Open Access Journals (Sweden)

    Maio Michele

    2004-06-01

    Full Text Available Abstract Passive immunotherapy with monoclonal antibodies (mAb targeted to specific tumor-associated antigens is amongst the most rapidly expanding approaches to biological therapy of cancer. However, until now a limited number of therapeutic mAb has demonstrated clinical efficacy in selected neoplasia. Results emerging from basic research point to a deeper characterization of specific biological features of neoplastic cells as crucial to optimize the clinical potential of therapeutic mAb, and to identify cancer patients who represent the best candidates to antibody-based immunotherapy. Focus on the tissue distribution and on the functional role of membrane complement-regulatory proteins such as Protectin (CD59, which under physiologic conditions protects tissues from Complement (C-damage, might help to optimize the efficacy of immunotherapeutic strategies based on C-activating mAb.

  1. Complement activation and choriocapillaris loss in early AMD: implications for pathophysiology and therapy.

    Science.gov (United States)

    Whitmore, S Scott; Sohn, Elliott H; Chirco, Kathleen R; Drack, Arlene V; Stone, Edwin M; Tucker, Budd A; Mullins, Robert F

    2015-03-01

    Age-related macular degeneration (AMD) is a common and devastating disease that can result in severe visual dysfunction. Over the last decade, great progress has been made in identifying genetic variants that contribute to AMD, many of which lie in genes involved in the complement cascade. In this review we discuss the significance of complement activation in AMD, particularly with respect to the formation of the membrane attack complex in the aging choriocapillaris. We review the clinical, histological and biochemical data that indicate that vascular loss in the choroid occurs very early in the pathogenesis of AMD, and discuss the potential impact of vascular dropout on the retinal pigment epithelium, Bruch's membrane and the photoreceptor cells. Finally, we present a hypothesis for the pathogenesis of early AMD and consider the implications of this model on the development of new therapies.

  2. Oligomerization of Mannan-binding Lectin Dictates Binding Properties and Complement Activation.

    Science.gov (United States)

    Kjaer, T R; Jensen, L; Hansen, A; Dani, R; Jensenius, J C; Dobó, J; Gál, P; Thiel, S

    2016-07-01

    The complement system is a part of the innate immune system and is involved in recognition and clearance of pathogens and altered-self structures. The lectin pathway of the complement system is initiated when soluble pattern recognition molecules (PRMs) with collagen-like regions bind to foreign or altered self-surfaces. Associated with the collagen-like stems of these PRMs are three mannan-binding lectin (MBL)-associated serine proteases (MASPs) and two MBL-associated proteins (MAps). The most studied of the PRMs, MBL, is present in serum mainly as trimeric and tetrameric oligomers of the structural subunit. We hypothesized that oligomerization of MBL may influence both the potential to bind to micro organisms and the interaction with the MASPs and MAps, thus influencing the ability to initiate complement activation. When testing binding at 37 °C, we found higher binding of tetrameric MBL to Staphylococcus aureus (S. aureus) than trimeric and dimeric MBL. In serum, we found that tetrameric MBL was the main oligomeric form present in complexes with the MASPs and MAp44. Such preference was confirmed using purified forms of recombinant MBL (rMBL) oligomers, where tetrameric rMBL interacted stronger with all of the MASPs and MAp44, compared to trimeric MBL. As a direct consequence of the weaker interaction with the MASPs, we found that trimeric rMBL was inferior to tetrameric rMBL in activating the complement system. Our data suggest that the oligomeric state of MBL is crucial both for the binding properties and the effector function of MBL.

  3. Alternative complement pathway activation during invasive coronary procedures in acute myocardial infarction and stable angina pectoris.

    Science.gov (United States)

    Horváth, Zsófia; Csuka, Dorottya; Vargova, Katarina; Kovács, Andrea; Leé, Sarolta; Varga, Lilian; Préda, István; Tóth Zsámboki, Emese; Prohászka, Zoltán; Kiss, Róbert Gábor

    2016-12-01

    The effect of invasive percutaneous coronary procedures on complement activation has not been elucidated. We enrolled stable angina patients with elective percutaneous coronary intervention (SA-PCI, n=24), diagnostic coronary angiography (CA, n=52) and 23 patients with ST segment elevation myocardial infarction and primary PCI (STEMI-PCI). Complement activation products (C1rC1sC1inh, C3bBbP and SC5b-9) were measured on admission, 6 and 24h after coronary procedures. The alternative pathway product, C3bBbP significantly and reversibly increased 6h after elective PCI (baseline: 7.81AU/ml, 6h: 16.09AU/ml, 24h: 4.27AU/ml, p<0.01, n=23) and diagnostic angiography (baseline: 6.13AU/ml, 6h: 12.08AU/ml, 24h: 5.4AU/ml, p<0.01, n=52). Six hour C3bBbP values correlated with post-procedural CK, creatinine level and the applied contrast material volume (r=0.41, r=0.4, r=0.3, p<0.05, respectively). In STEMI-PCI, baseline C3bBbP level was higher, compared to SA-PCI or CA patients (11.33AU/ml vs. 7.81AU/ml or 6.13AU/ml, p<0.001). Similarly, the terminal complex (SC5b-9) level was already elevated at baseline compared to SA-PCI group (3.49AU/ml vs. 1.87AU/ml, p=0.011). Complement pathway products did not increase further after primary PCI. Elective coronary procedures induced transient alternative complement pathway activation, influenced by the applied contrast volume. In STEMI, the alternative complement pathway is promptly activated during the atherothrombotic event and PCI itself had no further detectable effect.

  4. Nucleosomes and C1q bound to glomerular endothelial cells serve as targets for autoantibodies and determine complement activation.

    Science.gov (United States)

    O'Flynn, Joseph; Flierman, Roelof; van der Pol, Pieter; Rops, Angelique; Satchell, Simon C; Mathieson, Peter W; van Kooten, Cees; van der Vlag, Johan; Berden, Jo H; Daha, Mohamed R

    2011-10-01

    Various studies indicate a role for both anti-nucleosome and anti-C1q autoantibodies in glomerulonephritis in patients with systemic lupus erythematosus. However, a causal relationship between these autoantibodies and the development of lupus nephritis has not been fully established. Since injury of the endothelium is a major target in lupus nephritis we assessed the interaction of C1q and nucleosomes with glomerular endothelial cells in vitro in the presence or absence of autoantibodies against these antigens. We demonstrate a direct and dose-dependent binding of both nucleosomes and C1q to immortalized human glomerular endothelial cells (GEnC) in vitro, which in part is mediated by cell surface heparan sulfate. We demonstrate that nucleosomes and C1q serve as targets for monoclonal and polyclonal antibodies as well as for anti-nuclear autoantibodies from patients with systemic lupus erythematosus. An additive effect of anti-C1q autoantibodies on anti-nucleosome mediated complement activation was observed. Furthermore, we showed that the activation of complement on glomerular endothelial cells is mediated by the classical pathway since the deposition of C3 on GEnC is abrogated by MgEGTA and does not occur in C1q-depleted serum. Taken together, our studies demonstrate a direct binding of both nucleosomes and C1q to glomerular endothelial cells in vitro. The subsequent binding of autoantibodies against nucleosomes in patients with systemic lupus erythematosus is potentially pathogenic and autoantibodies against C1q seem to have an additional effect. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. The Serum Complement System: A Simplified Laboratory Exercise to Measure the Activity of an Important Component of the Immune System

    Science.gov (United States)

    Inglis, Jordan E.; Radziwon, Kimberly A.; Maniero, Gregory D.

    2008-01-01

    The immune system is a vital physiological component that affords animals protection from disease and is composed of innate and adaptive mechanisms that rely on cellular and dissolved components. The serum complement system is a series of dissolved proteins that protect against a variety of pathogens. The activity of complement in serum can be…

  6. The Serum Complement System: A Simplified Laboratory Exercise to Measure the Activity of an Important Component of the Immune System

    Science.gov (United States)

    Inglis, Jordan E.; Radziwon, Kimberly A.; Maniero, Gregory D.

    2008-01-01

    The immune system is a vital physiological component that affords animals protection from disease and is composed of innate and adaptive mechanisms that rely on cellular and dissolved components. The serum complement system is a series of dissolved proteins that protect against a variety of pathogens. The activity of complement in serum can be…

  7. Bacillus anthracis peptidoglycan activates human platelets through FcγRII and complement

    Science.gov (United States)

    Sun, Dawei; Popescu, Narcis I.; Raisley, Brent; Keshari, Ravi S.; Dale, George L.; Lupu, Florea

    2013-01-01

    Platelet activation frequently accompanies sepsis and contributes to the sepsis-associated vascular leakage and coagulation dysfunction. Our previous work has implicated peptidoglycan (PGN) as an agent causing systemic inflammation in gram-positive sepsis. We used flow cytometry and fluorescent microscopy to define the effects of PGN on the activation of human platelets. PGN induced platelet aggregation, expression of the activated form of integrin αIIbβ3, and exposure of phosphatidylserine (PS). These changes were dependent on immunoglobulin G and were attenuated by the Fcγ receptor IIa–blocking antibody IV.3, suggesting they are mediated by PGN–anti-PGN immune complexes signaling through Fcγ receptor IIa. PS exposure was not blocked by IV.3 but was sensitive to inhibitors of complement activation. PGN was a potent activator of the complement cascade in human plasma and caused deposition of C5b-9 on the platelet surface. Platelets with exposed PS had greatly accelerated prothrombinase activity. We conclude that PGN derived from gram-positive bacteria is a potent platelet agonist when complexed with anti-PGN antibody and could contribute to the coagulation dysfunction accompanying gram-positive infections. PMID:23733338

  8. Binding of Streptococcus pneumoniae endopeptidase O (PepO) to complement component C1q modulates the complement attack and promotes host cell adherence.

    Science.gov (United States)

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

    2014-05-30

    The Gram-positive species Streptococcus pneumoniae is a human pathogen causing severe local and life-threatening invasive diseases associated with high mortality rates and death. We demonstrated recently that pneumococcal endopeptidase O (PepO) is a ubiquitously expressed, multifunctional plasminogen and fibronectin-binding protein facilitating host cell invasion and evasion of innate immunity. In this study, we found that PepO interacts directly with the complement C1q protein, thereby attenuating the classical complement pathway and facilitating pneumococcal complement escape. PepO binds both free C1q and C1 complex in a dose-dependent manner based on ionic interactions. Our results indicate that recombinant PepO specifically inhibits the classical pathway of complement activation in both hemolytic and complement deposition assays. This inhibition is due to direct interaction of PepO with C1q, leading to a strong activation of the classical complement pathway, and results in consumption of complement components. In addition, PepO binds the classical complement pathway inhibitor C4BP, thereby regulating downstream complement activation. Importantly, pneumococcal surface-exposed PepO-C1q interaction mediates bacterial adherence to host epithelial cells. Taken together, PepO facilitates C1q-mediated bacterial adherence, whereas its localized release consumes complement as a result of its activation following binding of C1q, thus representing an additional mechanism of human complement escape by this versatile pathogen.

  9. Activation of the complement system and accumulation of hemoglobin-haptoglobin complexes in plasma during an adverse reaction to penicillin treatment.

    Science.gov (United States)

    Brandslund, I; Svehag, S E; Teisner, B; Hyltoft Petersen, P

    1983-01-01

    A patient treated with penicillin intravenously developed a serum sickness-like reaction. Classical pathway complement (C) activation was indicated by quantitation of the split products C3c and C3d as well as demonstration of C4 conversion. Circulating immune complexes could, however, not be detected by the solid-phase Clq and PEG-precipitation methods. A concomitant accumulation of circulating hemoglobin-haptoglobin complexes and a marked fall in serum-fibronectin concentrations suggested saturation of the reticuloendothelial system. The plasma became a deep-red color, and a diffuse intravascular coagulation followed. The patient recovered completely upon discontinuation of penicillin administration.

  10. Complement Activation in Arterial and Venous Thrombosis is Mediated by Plasmin

    Science.gov (United States)

    Foley, Jonathan H.; Walton, Bethany L.; Aleman, Maria M.; O'Byrne, Alice M.; Lei, Victor; Harrasser, Micaela; Foley, Kimberley A.; Wolberg, Alisa S.; Conway, Edward M.

    2016-01-01

    Thrombus formation leading to vaso-occlusive events is a major cause of death, and involves complex interactions between coagulation, fibrinolytic and innate immune systems. Leukocyte recruitment is a key step, mediated partly by chemotactic complement activation factors C3a and C5a. However, mechanisms mediating C3a/C5a generation during thrombosis have not been studied. In a murine venous thrombosis model, levels of thrombin–antithrombin complexes poorly correlated with C3a and C5a, excluding a central role for thrombin in C3a/C5a production. However, clot weight strongly correlated with C5a, suggesting processes triggered during thrombosis promote C5a generation. Since thrombosis elicits fibrinolysis, we hypothesized that plasmin activates C5 during thrombosis. In vitro, the catalytic efficiency of plasmin-mediated C5a generation greatly exceeded that of thrombin or factor Xa, but was similar to the recognized complement C5 convertases. Plasmin-activated C5 yielded a functional membrane attack complex (MAC). In an arterial thrombosis model, plasminogen activator administration increased C5a levels. Overall, these findings suggest plasmin bridges thrombosis and the immune response by liberating C5a and inducing MAC assembly. These new insights may lead to the development of strategies to limit thrombus formation and/or enhance resolution. PMID:27077125

  11. Complement Activation in Arterial and Venous Thrombosis is Mediated by Plasmin

    Directory of Open Access Journals (Sweden)

    Jonathan H. Foley

    2016-03-01

    Full Text Available Thrombus formation leading to vaso-occlusive events is a major cause of death, and involves complex interactions between coagulation, fibrinolytic and innate immune systems. Leukocyte recruitment is a key step, mediated partly by chemotactic complement activation factors C3a and C5a. However, mechanisms mediating C3a/C5a generation during thrombosis have not been studied. In a murine venous thrombosis model, levels of thrombin–antithrombin complexes poorly correlated with C3a and C5a, excluding a central role for thrombin in C3a/C5a production. However, clot weight strongly correlated with C5a, suggesting processes triggered during thrombosis promote C5a generation. Since thrombosis elicits fibrinolysis, we hypothesized that plasmin activates C5 during thrombosis. In vitro, the catalytic efficiency of plasmin-mediated C5a generation greatly exceeded that of thrombin or factor Xa, but was similar to the recognized complement C5 convertases. Plasmin-activated C5 yielded a functional membrane attack complex (MAC. In an arterial thrombosis model, plasminogen activator administration increased C5a levels. Overall, these findings suggest plasmin bridges thrombosis and the immune response by liberating C5a and inducing MAC assembly. These new insights may lead to the development of strategies to limit thrombus formation and/or enhance resolution.

  12. Regulator of complement activation (RCA) locus in chicken: identification of chicken RCA gene cluster and functional RCA proteins.

    Science.gov (United States)

    Oshiumi, Hiroyuki; Shida, Kyoko; Goitsuka, Ryo; Kimura, Yuko; Katoh, Jun; Ohba, Shinya; Tamaki, Yuichiroh; Hattori, Takashi; Yamada, Nozomi; Inoue, Norimitsu; Matsumoto, Misako; Mizuno, Shigeki; Seya, Tsukasa

    2005-08-01

    A 150-kb DNA fragment, which contains the gene of the chicken complement regulatory protein CREM (formerly named Cremp), was isolated from a microchromosome by screening bacterial artificial chromosome library. Within 100 kb of the cloned region, three complete genes encoding short consensus repeats (SCRs, motifs with tandemly arranged 60 aa) were identified by exon-trap method and 3'- or 5'-RACE. A chicken orthologue of the human gene 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 2, which exists in close proximity to the regulator of complement activation genes in humans and mice, was located near this chicken SCR gene cluster. Moreover, additional genes encoding SCR proteins appeared to be present in this region. Three distinct transcripts were detected in RNA samples from a variety of chicken organs and cell lines. Two novel genes named complement regulatory secretory protein of chicken (CRES) and complement regulatory GPI-anchored protein of chicken (CREG) besides CREM were identified by cloning corresponding cDNA. Based on the predicted primary structures and properties of the expressed molecules, CRES is a secretory protein, whereas CREG is a GPI-anchored membrane protein. CREG and CREM were protected host cells from chicken complement-mediated cytolysis. Likewise, a membrane-bound form of CRES, which was artificially generated, also protected host cells from chicken complement. Taken together, the chicken possesses an regulator of complement activation locus similar to those of the mammals, and the gene products function as complement regulators.

  13. The mechanisms of complement activation in normal bovine serum and normal horse serum against Yersinia enterocolitica O:9 strains with different outer membrane proteins content.

    Science.gov (United States)

    Miętka, K; Brzostek, K; Guz-Regner, K; Bugla-Płoskońska, G

    2016-01-01

    Yersinia enterocolitica is a common zoonotic pathogen and facultative intracellular bacterium which can survive within blood cells. Cattle and horses are considered a reservoir of Y. enterocolitica which often causes several serious syndromes associated with yersiniosis such as abortions, premature births or infertility. The aim of our investigation was to determine the vitality of Y. enterocolitica O:9 strains (Ye9) in bovine and horse sera (NBS and NHrS) and explain the role of outer membrane proteins (OMPs) in serum resistance of these bacteria. Our previous studies demonstrated moderate human serum (NHS) resistance of the wild type Ye9 strain, whereas mutants lacking YadA, Ail or OmpC remained sensitive to the bactericidal activity of NHS. The present study showed that the wild type of Ye9 strain was resistant to the bactericidal activity of both NHrS and NBS, while Ye9 mutants lacking the YadA, Ail and OmpC proteins were sensitive to NHrS and NBS as well as to NHS. The mechanisms of complement activation against Ye9 strains lacking Ail and YadA were distinguished, i.e. activation of the classical/lectin pathways decisive in the bactericidal mechanism of complement activation of NBS, parallel activation of the classical/lectin and alternative pathways of NHrS. In this research the mechanism of independent activation of the classical/lectin or the alternative pathway of NBS and NHrS against Ye9 lacking OmpC porin was also established. The results indicate that serum resistance of Ye9 is multifactorial, in which extracellular structures, i.e. outer membrane proteins (OMPs) such as Ail, OmpC or YadA, play the main role.

  14. Smoke Exposure Causes Endoplasmic Reticulum Stress and Lipid Accumulation in Retinal Pigment Epithelium through Oxidative Stress and Complement Activation*

    Science.gov (United States)

    Kunchithapautham, Kannan; Atkinson, Carl; Rohrer, Bärbel

    2014-01-01

    Age-related macular degeneration (AMD) is a complex disease caused by genetic and environmental factors, including genetic variants in complement components and smoking. Smoke exposure leads to oxidative stress, complement activation, endoplasmic reticulum (ER) stress, and lipid dysregulation, which have all been proposed to be associated with AMD pathogenesis. Here we examine the effects of smoke exposure on the retinal pigment epithelium (RPE). Mice were exposed to cigarette smoke or filtered air for 6 months. RPE cells grown as stable monolayers were exposed to 5% cigarette smoke extract (CSE). Effects of smoke were determined by biochemical, molecular, and histological measures. Effects of the alternative pathway (AP) of complement and complement C3a anaphylatoxin receptor signaling were analyzed using knock-out mice or specific inhibitors. ER stress markers were elevated after smoke exposure in RPE of intact mice, which was eliminated in AP-deficient mice. To examine this relationship further, RPE monolayers were exposed to CSE. Short term smoke exposure resulted in production and release of complement C3, the generation of C3a, oxidative stress, complement activation on the cell membrane, and ER stress. Long term exposure to CSE resulted in lipid accumulation, and secretion. All measures were reversed by blocking C3a complement receptor (C3aR), alternative complement pathway signaling, and antioxidant therapy. Taken together, our results provide clear evidence that smoke exposure results in oxidative stress and complement activation via the AP, resulting in ER stress-mediated lipid accumulation, and further suggesting that oxidative stress and complement act synergistically in the pathogenesis of AMD. PMID:24711457

  15. The complement system in systemic autoimmune disease.

    Science.gov (United States)

    Chen, Min; Daha, Mohamed R; Kallenberg, Cees G M

    2010-05-01

    Complement is part of the innate immune system. Its major function is recognition and elimination of pathogens via direct killing and/or stimulation of phagocytosis. Activation of the complement system is, however, also involved in the pathogenesis of the systemic autoimmune diseases. Activation via the classical pathway has long been recognized in immune complex-mediated diseases such as cryoglobulinemic vasculitis and systemic lupus erythematosus (SLE). In SLE, the role of complement is somewhat paradoxical. It is involved in autoantibody-initiated tissue damage on the one hand, but, on the other hand, it appears to have protective features as hereditary deficiencies of classical pathway components are associated with an increased risk for SLE. There is increasing evidence that the alternative pathway of complement, even more than the classical pathway, is involved in many systemic autoimmune diseases. This is true for IgA-dominant Henoch Schönlein Purpura, in which additional activation of the lectin pathway contributes to more severe disease. In anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis the complement system was considered not to be involved since immunoglobulin deposition is generally absent in the lesions. However, recent studies, both in human and animal models, demonstrated complement activation via the alternative pathway as a major pathogenic mechanism. Insight into the role of the various pathways of complement in the systemic autoimmune diseases including the vasculitides opens up new ways of treatment by blocking effector pathways of complement. This has been demonstrated for monoclonal antibodies to C5 or C5a in experimental anti-phospholipid antibody syndrome and ANCA-associated vasculitis.

  16. Preliminary Screening of a Classical Ayurvedic Formulation for Anticonvulsant Activity

    Directory of Open Access Journals (Sweden)

    Arnab Dhar

    2016-01-01

    Full Text Available Background: Epilepsy is a serious and complex central nervous system disorder associated with recurrent episodes of convulsive seizures due to the imbalance between excitatory (glutamatergic and inhibitory (GABAergic neurotransmitters level in the brain. The available treatments are neither competent to control the seizures nor prevent progress of disease. Since ages, Herbal medicines have remained important sources of medicines in many parts of world which is evidenced through their uses in traditional systems of medicine i.e. Ayurveda, Siddha, Unani, Homeopathy and Chinese etc. Aim: A polyherbal formulation (containing Terminalia chebula Retz., Asparagus racemosus Willd., Embelia ribes Burm. F, Acorus calamus L., Tinospora cordifolia (Willd. Miers, Convolvulus pluricaulis Choisy, Saussurea lappa C.B.Clarke, Achyranthes aspera L. is mentioned in Ayurvedic classics Bhaiṣajya Ratnāvali. The aim of the study was to evaluate the anticonvulsant activity of the formulation in Maximum electroshock and Pentylenetetrazole induced convulsions in rats. Materials and Methods: In the present study, a polyherbal formulation was developed as directed by classical text and evaluated for the anticonvulsant activity using Maximal Electroshock Shock (MES and Pentylenetetrazole (PTZ induced convulsions in rats. Statistical comparison was done by one way ANOVA followed by the Tukey's multiple comparison test. Results: The obtained results showed that the PHF had a protective role on epilepsy. Treatment with PHF significantly improves antioxidant enzymes activities of superoxide dismutase (SOD and glutathione (GSH levels significantly as compared to controls. PHF also significantly decreased malonaldialdehyde (MDA levels in the brain. Moreover, it also attenuated the PTZ-induced increase in the activity of GABA-T in the rat brain. Conclusion: These findings suggest that PHF might have possible efficacy in the treatment of epilepsy.

  17. Complement lysis activity in autologous plasma is associated with lower viral loads during the acute phase of HIV-1 infection.

    Directory of Open Access Journals (Sweden)

    Michael Huber

    2006-11-01

    Full Text Available BACKGROUND: To explore the possibility that antibody-mediated complement lysis contributes to viremia control in HIV-1 infection, we measured the activity of patient plasma in mediating complement lysis of autologous primary virus. METHODS AND FINDINGS: Sera from two groups of patients-25 with acute HIV-1 infection and 31 with chronic infection-were used in this study. We developed a novel real-time PCR-based assay strategy that allows reliable and sensitive quantification of virus lysis by complement. Plasma derived at the time of virus isolation induced complement lysis of the autologous virus isolate in the majority of patients. Overall lysis activity against the autologous virus and the heterologous primary virus strain JR-FL was higher at chronic disease stages than during the acute phase. Most strikingly, we found that plasma virus load levels during the acute but not the chronic infection phase correlated inversely with the autologous complement lysis activity. Antibody reactivity to the envelope (Env proteins gp120 and gp41 were positively correlated with the lysis activity against JR-FL, indicating that anti-Env responses mediated complement lysis. Neutralization and complement lysis activity against autologous viruses were not associated, suggesting that complement lysis is predominantly caused by non-neutralizing antibodies. CONCLUSIONS: Collectively our data provide evidence that antibody-mediated complement virion lysis develops rapidly and is effective early in the course of infection; thus it should be considered a parameter that, in concert with other immune functions, steers viremia control in vivo.

  18. Sundanese Complementation

    Science.gov (United States)

    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,…

  19. Proteomic Profiling Analysis Reveals a Link between Experimental Autoimmune Uveitis and Complement Activation in Rats.

    Science.gov (United States)

    Guo, D D; Hu, B; Tang, H Y; Sun, Y Y; Liu, B; Tian, Q M; Bi, H S

    2017-05-01

    Uveitis is an autoimmune disease that usually damages the vision function, leading to poor visual quality in patients. As an autoimmune ocular inflammatory disease, the pathogenesis of uveitis is associated with abnormal expression of some proteins and aberrant regulation of multiple signalling pathways. Nevertheless, the detailed mechanism remains unclear. In this study, we induced an experimental autoimmune uveitis (EAU) model in rats. We determined the levels of C3a and membrane attack complex C5b-9 (soluble C5b-9, sC5b-9) in both plasma and aqueous humour, identified the differentially expressed proteins in plasma by liquid chromatography-tandem mass spectrometry and employed bioinformatics algorithms to analyse differentially expressed proteins in EAU rat plasma. The results demonstrate that there were 168 differentially expressed plasma proteins in EAU rats versus control subjects. The levels of sC5b-9 and C3a were elevated in the plasmas and aqueous humours of EAU rats. Gene ontology enrichment analysis showed that the differentially expressed proteins in EAU rat plasma were mainly involved in metabolic and immune processes. Kyoto encyclopedia of genes and genomes (KEGG) pathway annotation, database for annotation, visualization and integrated discovery (DAVID) and protein-protein interaction analyses revealed that the differentially expressed proteins in EAU rat plasmas were closely associated with complement and coagulation cascades, metabolic pathways, NF-kappa B, PI3K-Akt, Toll-like receptors and autophagy. Overall, the differentially expressed proteins in EAU rat plasmas are mainly involved in the complement and coagulation cascades. The pathogenesis of uveitis closely correlates with complement activation. © 2017 The Foundation for the Scandinavian Journal of Immunology.

  20. Complement activation and kidney injury molecule-1-associated proximal tubule injury in severe preeclampsia.

    Science.gov (United States)

    Burwick, Richard M; Easter, Sarah Rae; Dawood, Hassan Y; Yamamoto, Hidemi S; Fichorova, Raina N; Feinberg, Bruce B

    2014-10-01

    Kidney injury with proteinuria is a characteristic feature of preeclampsia, yet the nature of injury in specific regions of the nephron is incompletely understood. Our study aimed to use existing urinary biomarkers to describe the pattern of kidney injury and proteinuria in pregnancies affected by severe preeclampsia. We performed a case-control study of pregnant women from Brigham and Women's Hospital from 2012 to 2013. We matched cases of severe preeclampsia (n=25) 1:1 by parity and gestational age to 2 control groups with and without chronic hypertension. Urinary levels of kidney injury molecule-1 and complement components (C3a, C5a, and C5b-9) were measured by enzyme-linked immunosorbent assay, and other markers (albumin, β2 microglobulin, cystatin C, epithelial growth factor, neutrophil gelatinase-associated lipocalin, osteopontin, and uromodulin) were measured simultaneously with a multiplex electrochemiluminescence assay. Median values between groups were compared with the Wilcoxon signed-rank test and correlations with Spearman correlation coefficient. Analysis of urinary markers revealed higher excretion of albumin and kidney injury molecule-1 and lower excretion of neutrophil gelatinase-associated lipocalin and epithelial growth factor in severe preeclampsia compared with chronic hypertension and healthy controls. Among subjects with severe preeclampsia, urinary excretion of complement activation products correlated most closely with kidney injury molecule-1, a specific marker of proximal tubule injury (C5a: r=0.60; P=0.001; and C5b-9: r=0.75; Pkidney injury in severe preeclampsia that is characterized by glomerular impairment and complement-mediated inflammation and injury, possibly localized to the proximal tubule in association with kidney injury molecule-1.

  1. Mechanisms of complement activation by dextran-coated superparamagnetic iron oxide (SPIO) nanoworms in mouse versus human serum

    DEFF Research Database (Denmark)

    Banda, Nirmal K; Mehta, Gaurav; Chao, Ying

    2014-01-01

    BACKGROUND: The complement system is a key component of innate immunity implicated in the neutralization and clearance of invading pathogens. Dextran coated superparamagnetic iron oxide (SPIO) nanoparticle is a promising magnetic resonance imaging (MRI) contrast agent. However, dextran SPIO has...... pathway (LP) or alternative pathway (AP) components were used to study mechanisms of mouse complement activation. In vitro measurements of fluid phase markers of complement activation C4d and Bb and the terminal pathway marker SC5b-C9 in normal and genetically deficient sera were used to study...... the CP, but that did not affect the total level of C3 deposition on the particles. CONCLUSIONS: There were important differences and similarities in the complement activation by SPIO NW in mouse versus human sera. Understanding the mechanisms of immune recognition of nanoparticles in mouse and human...

  2. VARIATIONS IN THE COMPLEMENT ACTIVITY AND FIXABILITY OF GUINEA PIG SERUM.

    Science.gov (United States)

    Noguchi, H; Bronfenbrenner, J

    1911-01-01

    The following conclusions may be drawn from the foregoing series of experiments. The complementary activity varies within a definite limit in different specimens of guinea pig serum. With sera which stood in contact with the clot for twenty hours, the strongest and weakest were in the ratio of 0.015 cubic centimeter to 0.04 cubic centimeter. The former was 2.66 times stronger than the latter. The variation observed with the same series of sera after forty-six hours was still more striking. The strongest was 0.013 cubic centimeter, and the weakest, 0.06 cubic centimeter, that is, the former was 4.6 times stronger than the latter. These findings agree with those made by Massol and Grysez. The variations were not so marked with the majority of sera. It is noteworthy that a large number of the sera gained in the complementary activity when remaining in contact with the clot for forty-six hours, while some sera became weakened during the same length of time. The amount of serum fixed by given constant quantities of syphilitic serum and antigen varies much more markedly than the variations in their complementary activity. One serum failed altogether to be fixed. On the other hand, one sample of serum was so easily fixable that 0.24 cubic centimeter (corresponding to 9.6 complement units of this specimen) disappeared, while the average quantity fixed was only 0.098 cubic centimeter (corresponding to 4.64 complement units). The normal standard of fixability was shown in about 50 per cent. of the specimens examined. If the zone of normal fixability is enlarged in both directions by one unit, the percentage of normal fixability would become 65.8. There is no definite relationship between the complementary activity and the fixability of a given specimen of guinea pig serum. The facts derived from our present experiments, especially in regard to the exceptions in the fixative quality of this serum, demand the utmost precaution from those intending to employ it for diagnostic

  3. Antibody directs properdin-dependent activation of the complement alternative pathway in a mouse model of abdominal aortic aneurysm.

    Science.gov (United States)

    Zhou, Hui-Fang; Yan, Huimin; Stover, Cordula M; Fernandez, Tamara Montes; Rodriguez de Cordoba, Santiago; Song, Wen-Chao; Wu, Xiaobo; Thompson, Robert W; Schwaeble, Wilhelm J; Atkinson, John P; Hourcade, Dennis E; Pham, Christine T N

    2012-02-14

    Abdominal aortic aneurysm (AAA) is a complex inflammatory vascular disease. There are currently limited treatment options for AAA when surgery is inapplicable. Therefore, insights into molecular mechanisms underlying AAA pathogenesis may reveal therapeutic targets that could be manipulated pharmacologically or biologically to halt disease progression. Using an elastase-induced AAA mouse model, we previously established that the complement alternative pathway (AP) plays a critical role in the development of AAA. However, the mechanism by which complement AP is initiated remains undefined. The complement protein properdin, traditionally viewed as a positive regulator of the AP, may also initiate complement activation by binding directly to target surfaces. In this study, we sought to determine whether properdin serves as a focal point for the initiation of the AP complement activation in AAA. Using a properdin loss of function mutation in mice and a mutant form of the complement factor B protein that produces a stable, properdin-free AP C3 convertase, we show that properdin is required for the development of elastase-induced AAA in its primary role as a convertase stabilizer. Unexpectedly, we find that, in AAA, natural IgG antibodies direct AP-mediated complement activation. The absence of IgG abrogates C3 deposition in elastase-perfused aortic wall and protects animals from AAA development. We also determine that blockade of properdin activity prevents aneurysm formation. These results indicate that an innate immune response to self-antigens activates the complement system and initiates the inflammatory cascade in AAA. Moreover, the study suggests that properdin-targeting strategies may halt aneurysmal growth.

  4. Studies on the phenylethanoid glycosides with anti-complement activity from Paulownia tomentosa var. tomentosa wood.

    Science.gov (United States)

    Si, Chuan-Ling; Deng, Xiao-Juan; Liu, Zhong; Kim, Jin-Kyu; Bae, Young-Soo

    2008-01-01

    Four epimeric phenylethanoid glycosides, including a new one, R,S-beta-ethoxy-beta-(3,4-dihydroxyphenyl)-ethyl-O-alpha-L-rhamnopyranosyl(1-->3)-beta-D-(6-O-E-caffeoyl)-glucopyranoside named isoilicifolioside A (1), and three known compounds, ilicifolioside A (2), campneoside II (3), and isocampneoside II (4), were isolated from Paulownia tomentosa var. tomentosa wood. The structures of the four compounds were elucidated by the interpretation of 1D and 2D NMR and MS spectra. This is the first report of the chemical profile of this tree. Compounds 1-4 exhibited excellent anti-complement activity with IC(50) values less than 74 microM, compared with tiliroside (IC(50) = 104 microM) and rosmarinic acid (IC(50) = 182 microM) that were used as positive controls.

  5. A HEPARIN-COATED CIRCUIT REDUCES COMPLEMENT ACTIVATION AND THE RELEASE OF LEUKOCYTE INFLAMMATORY MEDIATORS DURING EXTRACORPOREAL-CIRCULATION IN A RABBIT

    NARCIS (Netherlands)

    PLOTZ, FB; VANOEVEREN, W; HULTQUIST, KA; MILLER, C; BARTLETT, RH; WILDEVUUR, CRH

    1992-01-01

    Heparin coating modifies complement activation during extracorporeal circulation much more effectively than systemically administered heparin. This rabbit study was undertaken to address possible mechanisms responsible for this difference. We evaluated the effect of heparin coating on complement act

  6. Synchronization of Active Atomic Clocks via Quantum and Classical Channels

    CERN Document Server

    Roth, Alexander

    2016-01-01

    Superradiant lasers based on atomic ensembles exhibiting ultra-narrow optical transitions can emit light of unprecedented spectral purity and may serve as active atomic clocks. We consider two frequency-detuned active atomic clocks, which are coupled in a cascaded setup, i.e. as master & slave lasers, and study the synchronization of the slave to the master clock. In a setup where both atomic ensembles are coupled to a common cavity mode such synchronization phenomena have been predicted by Xu et al. [Phys. Rev. Lett. 113, 154101 (2014)] and experimentally observed by Weiner et al. [arXiv:1503.06464 (2015)]. Here we demonstrate that synchronization still occurs in cascaded setups but exhibits distinctly different phase diagrams. We study the characteristics of synchronization in comparison to the case of coupling through a common cavity. We also consider synchronization through a classical channel where light of the master laser is measured phase sensitively and the slave laser is injection locked by feed...

  7. Activating KIR/HLA complexes in classic Kaposi's Sarcoma

    Directory of Open Access Journals (Sweden)

    Guerini Franca R

    2012-04-01

    Full Text Available Abstract Background Classic Kaposi's Sarcoma (cKS is a rare vascular tumor associated with Human Herpesvirus 8 (KSHV infection, nevertheless not all KSHV-infected individuals have cKS. Objective We investigated whether particular KIR/HLA receptor/ligand genotypes would be preferentially present in KSHV-infected and uninfected individuals who have or have not developed cKS. Methods KIR/HLA genotypes were analyzed by molecular genotyping in 50 KSHV-infected individuals who did or did not have cKS and in 33 age-and sex-matched KSHV seronegative individuals. Results There was no association of individual KIR, HLA or receptor ligand combinations with KSHV infection. However, activating KIR and KIR/HLA genotypes were significantly more frequent in cKS cases, specifically KIR3DS1, KIR2DS1, and KIR2DS1 with its HLA-C2 ligand. Conclusion A nonspecific inflammatory response triggered by activation of NK cells upon KIR-HLA interaction could be associated with the pathogenesis of KS.

  8. Synchronization of active atomic clocks via quantum and classical channels

    Science.gov (United States)

    Roth, Alexander; Hammerer, Klemens

    2016-10-01

    Superradiant lasers based on atomic ensembles exhibiting ultranarrow optical transitions can emit light of unprecedented spectral purity and may serve as active atomic clocks. We consider two frequency-detuned active atomic clocks, which are coupled in a cascaded setup, i.e., as master and slave lasers, and study the synchronization of the slave to the master clock. In a setup where both atomic ensembles are coupled to a common cavity mode, such synchronization phenomena have been predicted by Xu et al. [M. Xu, D. A. Tieri, E. C. Fine, J. K. Thompson, and M. J. Holland, Phys. Rev. Lett. 113, 154101 (2014)., 10.1103/PhysRevLett.113.154101] and experimentally observed by Weiner et al. (J. M. Weiner et al., arXiv:1503.06464). Here we demonstrate that synchronization still occurs in cascaded setups but exhibits distinctly different phase diagrams. We study the characteristics of synchronization in comparison to the case of coupling through a common cavity. We also consider synchronization through a classical channel where light of the master laser is measured phase sensitively and the slave laser is injection locked by feedback and compare to the results achievable by coupling through quantum channels.

  9. Bothrops asper snake venom and its metalloproteinase BaP–1 activate the complement system. Role in leucocyte recruitment

    Directory of Open Access Journals (Sweden)

    Sandra H. P. Farsky

    2000-01-01

    Full Text Available The venom of the snake Bothrops asper, the most important poisonous snake in Central America, evokes an inflammatory response, the mechanisms of which are not well characterized. The objectives of this study were to investigate whether B. asper venom and its purified toxins – phospholipases and metalloproteinase – activate the complement system and the contribution of the effect on leucocyte recruitment. In vitro chemotaxis assays were performed using Boyden's chamber model to investigate the ability of serum incubated with venom and its purified toxins to induce neutrophil migration. The complement consumption by the venom was evaluated using an in vitro haemolytic assay. The importance of complement activation by the venom on neutrophil migration was investigated in vivo by injecting the venom into the peritoneal cavity of C5-deficient mice. Data obtained demonstrated that serum incubated with crude venom and its purified metalloproteinase BaP–1 are able to induce rat neutrophil chemotaxis, probably mediated by agent(s derived from the complement system. This hypothesis was corroborated by the capacity of the venom to activate this system in vitro. The involvement of C5a in neutrophil chemotaxis induced by venom-activated serum was demonstrated by abolishing migration when neutrophils were pre-incubated with antirat C5a receptor antibody. The relevance of the complement system in in vivo leucocyte mobilization was further demonstrated by the drastic decrease of this response in C5-deficient mice. Pre-incubation of serum with the soluble human recombinant complement receptor type 1 (sCR 1 did not prevent the response induced by the venom, but abolished the migration evoked by metalloproteinase-activated serum. These data show the role of the complement system in bothropic envenomation and the participation of metalloproteinase in the effect. Also, they suggest that the venom may contain other component(s which can cause direct activation

  10. Surviving mousepox infection requires the complement system.

    Directory of Open Access Journals (Sweden)

    Elizabeth A Moulton

    2008-12-01

    Full Text Available Poxviruses subvert the host immune response by producing immunomodulatory proteins, including a complement regulatory protein. Ectromelia virus provides a mouse model for smallpox where the virus and the host's immune response have co-evolved. Using this model, our study investigated the role of the complement system during a poxvirus infection. By multiple inoculation routes, ectromelia virus caused increased mortality by 7 to 10 days post-infection in C57BL/6 mice that lack C3, the central component of the complement cascade. In C3(-/- mice, ectromelia virus disseminated earlier to target organs and generated higher peak titers compared to the congenic controls. Also, increased hepatic inflammation and necrosis correlated with these higher tissue titers and likely contributed to the morbidity in the C3(-/- mice. In vitro, the complement system in naïve C57BL/6 mouse sera neutralized ectromelia virus, primarily through the recognition of the virion by natural antibody and activation of the classical and alternative pathways. Sera deficient in classical or alternative pathway components or antibody had reduced ability to neutralize viral particles, which likely contributed to increased viral dissemination and disease severity in vivo. The increased mortality of C4(-/- or Factor B(-/- mice also indicates that these two pathways of complement activation are required for survival. In summary, the complement system acts in the first few minutes, hours, and days to control this poxviral infection until the adaptive immune response can react, and loss of this system results in lethal infection.

  11. Parallel activities and interactions between antimicrobial peptides and complement in host defense at the airway epithelial surface.

    Science.gov (United States)

    Hiemstra, Pieter S

    2015-11-01

    Antimicrobial peptides and complement components contribute to host defense as well as inflammation and tissue injury in the respiratory tract. The airway epithelial surface is the main site of action of these immune effectors, and airway epithelial cells contribute markedly to their local production. Whereas both antimicrobial peptides and complement display overlapping functions, it is increasingly clear that both effector mechanisms also interact. Furthermore, excessive or uncontrolled release of antimicrobial peptides as well as complement activation may contribute to inflammatory lung diseases. Therefore, further knowledge of interactions between these systems may provide more insight into the pathogenesis of a range of lung diseases. In this review, recent findings on the functions, collaborations and other interactions between antimicrobial peptides and complement are discussed with a specific focus on the airway epithelium.

  12. Effects of Anti-CD59 on Complement- induced Platelet Activation in Adult Males with Coronary Heart Disease

    Institute of Scientific and Technical Information of China (English)

    王礼春; 马虹; 黄守坚; 麦炜颐; 董吁钢; 曾武涛; 廖新学; 何建桂; 徐冬

    2003-01-01

    Objectives To study the reactions of platelet to active complement and the ef-fects of anti- CD59 on platelet activation induced bycomplement in coronary heart disease (CHD) adultmales. Methods By applying cobra venom factor(CVF) to activate complement, observed the plateletaggregation and release reactions induced by activecomplement with or without applying anti- CD59 toblock the complement modulation protein CD59.Results CVF could induce platelet of CHD individ-uals release ATP and cause significant and lastingmetamorphosis, but failed to induce platelet aggregate.The platelet maximum shape change showed positivelinear correlation with lg concentration of CVF. Theregressive equation was Y=28.7171gx - 19. 798 ( r =0. 956, P <0.01, n = 36). Anti - CD59 could enhanceCVF- induced platelet shape change and ATP releasewith a dose-dependent manner. ConclusionsComplement activated by CVF can induce significantand lasting platelet metamorphosis and release reac-tion, but can't induce platelet aggregation in CHD adultmales. Anti -CD59 can promote the platelet reactionsinduced by active complement.

  13. Release and characterization of single side chains of white cabbage pectin and their complement-fixing activity.

    Science.gov (United States)

    Westereng, Bjorge; Coenen, Gerd Jan; Michaelsen, Terje Einar; Voragen, Alphons G J; Samuelsen, Anne Berit; Schols, Henk A; Knutsen, Svein Halvor

    2009-06-01

    A mixture of single side chains from white cabbage pectin were obtained by anion exchange chromatography after applying mild chemical conditions promoting beta-elimination. These pectin fragments were characterized by their molecular weight distribution, sugar composition, 13C-NMR, and MALDI-TOF-MS analysis. These analyses revealed that the large oligosaccharides released by beta-eliminative treatment were composed of alpha-1,5 linked arabinosyl residues with 2- and 3-linked alpha-arabinosyl side chains, and, or beta-1,4 linked galactosyl side chains. Fractions were tested for complement-fixing activity in order to determine their interaction with the complement system. These results strongly indicated that there was a minimal unit size responsible for the complement-fixing activity. Neutral pectin fragments (8 kDa) obtained from beta-elimination were inactive in the complement system, although they contained a sugar composition previously shown to be highly active. Larger pectin fragments (17 kDa) retained some activity, but much lower than polymers containing rhamnogalacturonan type 1 (RGI) structures isolated from the same source. This implied that structural elements containing multiple side chains is necessary for efficient complement-fixing activity.

  14. Complement associated pathogenic mechanisms in myasthenia gravis.

    Science.gov (United States)

    Tüzün, Erdem; Christadoss, Premkumar

    2013-07-01

    The complement system is profoundly involved in the pathogenesis of acetylcholine receptor (AChR) antibody (Ab) related myasthenia gravis (MG) and its animal model experimental autoimmune myasthenia gravis (EAMG). The most characteristic finding of muscle pathology in both MG and EAMG is the abundance of IgG and complement deposits at the nerve-muscle junction (NMJ), suggesting that AChR-Ab induces muscle weakness by complement pathway activation and consequent membrane attack complex (MAC) formation. This assumption has been supported with EAMG resistance of complement factor C3 knockout (KO), C4 KO and C5 deficient mice and amelioration of EAMG symptoms following treatment with complement inhibitors such as cobra venom factor, soluble complement receptor 1, anti-C1q, anti-C5 and anti-C6 Abs. Moreover, the complement inhibitor decay accelerating factor (DAF) KO mice exhibit increased susceptibility to EAMG. These findings have brought forward improvisation of novel therapy methods based on inhibition of classical and common complement pathways in MG treatment.

  15. Contribution of chondroitin sulfate A to the binding of complement proteins to activated platelets.

    Directory of Open Access Journals (Sweden)

    Osama A Hamad

    Full Text Available BACKGROUND: Exposure of chondroitin sulfate A (CS-A on the surface of activated platelets is well established. The aim of the present study was to investigate to what extent CS-A contributes to the binding of the complement recognition molecule C1q and the complement regulators C1 inhibitor (C1INH, C4b-binding protein (C4BP, and factor H to platelets. PRINCIPAL FINDINGS: Human blood serum was passed over Sepharose conjugated with CS-A, and CS-A-specific binding proteins were identified by Western blotting and mass spectrometric analysis. C1q was shown to be the main protein that specifically bound to CS-A, but C4BP and factor H were also shown to interact. Binding of C1INH was dependent of the presence of C1q and then not bound to CS-A from C1q-depleted serum. The specific interactions observed of these proteins with CS-A were subsequently confirmed by surface plasmon resonance analysis using purified proteins. Importantly, C1q, C4BP, and factor H were also shown to bind to activated platelets and this interaction was inhibited by a CS-A-specific monoclonal antibody, thereby linking the binding of C1q, C4BP, and factor H to exposure of CS-A on activated platelets. CS-A-bound C1q was also shown to amplify the binding of model immune complexes to both microtiter plate-bound CS-A and to activated platelets. CONCLUSIONS: This study supports the concept that CS-A contributes to the binding of C1q, C4BP, and factor H to platelets, thereby adding CS-A to the previously reported binding sites for these proteins on the platelet surface. CS-A-bound C1q also seems to amplify the binding of immune complexes to activated platelets, suggesting a role for this molecule in immune complex diseases.

  16. Reduced neuronal cell death after experimental brain injury in mice lacking a functional alternative pathway of complement activation

    Directory of Open Access Journals (Sweden)

    Huber-Lang Markus

    2006-07-01

    Full Text Available Abstract Background Neuroprotective strategies for prevention of the neuropathological sequelae of traumatic brain injury (TBI have largely failed in translation to clinical treatment. Thus, there is a substantial need for further understanding the molecular mechanisms and pathways which lead to secondary neuronal cell death in the injured brain. The intracerebral activation of the complement cascade was shown to mediate inflammation and tissue destruction after TBI. However, the exact pathways of complement activation involved in the induction of posttraumatic neurodegeneration have not yet been assessed. In the present study, we investigated the role of the alternative complement activation pathway in contributing to neuronal cell death, based on a standardized TBI model in mice with targeted deletion of the factor B gene (fB-/-, a "key" component required for activation of the alternative complement pathway. Results After experimental TBI in wild-type (fB+/+ mice, there was a massive time-dependent systemic complement activation, as determined by enhanced C5a serum levels for up to 7 days. In contrast, the extent of systemic complement activation was significantly attenuated in fB-/- mice (P fB-/- vs. fB+/+; t = 4 h, 24 h, and 7 days after TBI. TUNEL histochemistry experiments revealed that posttraumatic neuronal cell death was clearly reduced for up to 7 days in the injured brain hemispheres of fB-/- mice, compared to fB+/+ littermates. Furthermore, a strong upregulation of the anti-apoptotic mediator Bcl-2 and downregulation of the pro-apoptotic Fas receptor was detected in brain homogenates of head-injured fB-/- vs. fB+/+ mice by Western blot analysis. Conclusion The alternative pathway of complement activation appears to play a more crucial role in the pathophysiology of TBI than previously appreciated. This notion is based on the findings of (a the significant attenuation of overall complement activation in head-injured fB-/- mice, as

  17. Activation of the human complement system by cholesterol-rich and pegylated liposomes - Modulation of cholesterol-rich liposome-mediated complement activation by elevated serum LDL and HDL levels

    DEFF Research Database (Denmark)

    Moghimi, S.M.; Hamad, I.; Bunger, R.;

    2006-01-01

    Intravenously infused liposomes may induce cardiopulmonary distress in some human subjects, which is a manifestation of "complement activation-related pseudoallergy." We have now examined liposome-mediated complement activation in human sera with elevated lipoprotein (LDL and HDL) levels, since...... level of S-protein-bound form of the terminal complex (SC5b-9). However, liposome-induced rise of SC5b-9 was significantly suppressed when serum HDL cholesterol levels increased by 30%. Increase of serum LDL to levels similar to that observed in heterozygous familial hypercholesterolemia also suppressed...

  18. Molecules Great and Small: The Complement System.

    Science.gov (United States)

    Mathern, Douglas R; Heeger, Peter S

    2015-09-04

    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

  19. Complement activation as a bioequivalence issue relevant to the development of generic liposomes and other nanoparticulate drugs

    NARCIS (Netherlands)

    Szebeni, Janos; Storm, G

    2015-01-01

    Liposomes are known to activate the complement (C) system, which can lead in vivo to a hypersensitivity syndrome called C activation-related pseudoallergy (CARPA). CARPA has been getting increasing attention as a safety risk of i.v. therapy with liposomes, whose testing is now recommended in bioequi

  20. Activation of the complement cascade enhances motility of leukemic cells by downregulating expression of HO-1.

    Science.gov (United States)

    Abdelbaset-Ismail, A; Borkowska-Rzeszotek, S; Kubis, E; Bujko, K; Brzeźniakiewicz-Janus, K; Bolkun, L; Kloczko, J; Moniuszko, M; Basak, G W; Wiktor-Jedrzejczak, W; Ratajczak, M Z

    2017-02-01

    As a crucial arm of innate immunity, the complement cascade (ComC) is involved both in mobilization of normal hematopoietic stem/progenitor cells (HSPCs) from bone marrow (BM) into peripheral blood and in their homing to BM. Despite the fact that ComC cleavage fragments alone do not chemoattract normal HSPCs, we found that leukemia cell lines as well as clonogenic blasts from chronic myeloid leukemia and acute myeloid leukemia patients respond robustly to C3 and C5 cleavage fragments by chemotaxis and increased adhesion. This finding was supported by the detection of C3a and C5a receptors in cells from human malignant hematopoietic cell lines and patient blasts at the mRNA (reverse transcriptase-polymerase chain reaction) and protein level (fluorescence-activated cell sorting), and by the demonstration that these receptors respond to stimulation by C3a and C5a by phosphorylation of p42/44 and p38 mitogen-activated protein kinases (MAPK), and protein kinase B (PKB/AKT). We also found that inducible heme oxygenase 1 (HO-1) is a negative regulator of ComC-mediated trafficking of leukemic cells, and that stimulation of leukemic cells by C3 or C5 cleavage fragments activates p38 MAPK, which downregulates HO-1 expression, rendering cells more mobile. We conclude that activation of the ComC in leukemia/lymphoma patients (for example, as a result of accompanying infections) enhances the motility of malignant cells and contributes to their spread in a p38 MAPK-HO-1-dependent manner. Therefore, inhibition of p38 MAPK or upregulation of HO-1 by small-molecule modulators would have a beneficial effect on ameliorating cell migration-mediated expansion of leukemia/lymphoma cells when the ComC becomes activated.

  1. MRI changes and complement activation correlate with epileptogenicity in a mouse model of temporal lobe epilepsy.

    Science.gov (United States)

    Kharatishvili, Irina; Shan, Zuyao Y; She, David T; Foong, Samuel; Kurniawan, Nyoman D; Reutens, David C

    2014-03-01

    The complex pathogenesis of temporal lobe epilepsy includes neuronal and glial pathology, synaptic reorganization, and an immune response. However, the spatio-temporal pattern of structural changes in the brain that provide a substrate for seizure generation and modulate the seizure phenotype is yet to be completely elucidated. We used quantitative magnetic resonance imaging (MRI) to study structural changes triggered by status epilepticus (SE) and their association with epileptogenesis and with activation of complement component 3 (C3). SE was induced by injection of pilocarpine in CD1 mice. Quantitative diffusion-weighted imaging and T2 relaxometry was performed using a 16.4-Tesla MRI scanner at 3 h and 1, 2, 7, 14, 28, 35, and 49 days post-SE. Following longitudinal MRI examinations, spontaneous recurrent seizures and interictal spikes were quantified using continuous video-EEG monitoring. Immunohistochemical analysis of C3 expression was performed at 48 h, 7 days, and 4 months post-SE. MRI changes were dynamic, reflecting different outcomes in relation to the development of epilepsy. Apparent diffusion coefficient changes in the hippocampus at 7 days post-SE correlated with the severity of the evolving epilepsy. C3 activation was found in all stages of epileptogenesis within the areas with significant MRI changes and correlated with the severity of epileptic condition.

  2. Decreased material-activation of the complement system using low-energy plasma polymerized poly(vinyl pyrrolidone) coatings

    DEFF Research Database (Denmark)

    Andersen, T.E.; Kolmos, H.J.; Palarasah, Yaseelan

    2011-01-01

    surface. The ppVP surface is furthermore characterized physically and chemically using scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR), which indicates preservation of chemical functionality by the applied plasma process. Overall, the pp......In the current study we investigate the activation of blood complement on medical device silicone rubber and present a plasma polymerized vinyl pyrrolidone (ppVP) coating which strongly decreases surface-activation of the blood complement system. We show that uncoated silicone and polystyrene...

  3. Astrocyte-Microglia Cross Talk through Complement Activation Modulates Amyloid Pathology in Mouse Models of Alzheimer's Disease

    OpenAIRE

    Lian, Hong; Litvinchuk, Alexandra; Chiang, Angie C.-A.; Aithmitti, Nadia; Jankowsky, Joanna L; Zheng, Hui

    2016-01-01

    Increasing evidence supports a role of neuroinflammation in the pathogenesis of Alzheimer's disease (AD). Previously, we identified a neuron–glia signaling pathway whereby Aβ acts as an upstream activator of astroglial nuclear factor kappa B (NF-κB), leading to the release of complement C3, which acts on the neuronal C3a receptor (C3aR) to influence dendritic morphology and cognitive function. Here we report that astrocytic complement activation also regulates Aβ dynamics in vitro and amyloid...

  4. Characterization of the complement inhibitory function of rhesus rhadinovirus complement control protein (RCP).

    Science.gov (United States)

    Okroj, Marcin; Mark, Linda; Stokowska, Anna; Wong, Scott W; Rose, Nicola; Blackbourn, David J; Villoutreix, Bruno O; Spiller, O Brad; Blom, Anna M

    2009-01-02

    Rhesus rhadinovirus (RRV) is currently the closest known, fully sequenced homolog of human Kaposi sarcoma-associated herpesvirus. Both these viruses encode complement inhibitors as follows: Kaposi sarcoma-associated herpesvirus-complement control protein (KCP) and RRV-complement control protein (RCP). Previously we characterized in detail the functional properties of KCP as a complement inhibitor. Here, we performed comparative analyses for two variants of RCP protein, encoded by RRV strains H26-95 and 17577. Both RCP variants and KCP inhibited human and rhesus complement when tested in hemolytic assays measuring all steps of activation via the classical and the alternative pathway. RCP variants from both RRV strains supported C3b and C4b degradation by factor I and decay acceleration of the classical C3 convertase, similar to KCP. Additionally, the 17577 RCP variant accelerated decay of the alternative C3 convertase, which was not seen for KCP. In contrast to KCP, RCP showed no affinity to heparin and is the first described complement inhibitor in which the binding site for C3b/C4b does not interact with heparin. Molecular modeling shows a structural disruption in the region of RCP that corresponds to the KCP-heparin-binding site. This makes RRV a superior model for future in vivo investigations of complement evasion, as RCP does not play a supportive role in viral attachment as KCP does.

  5. Factor H-related protein 5 interacts with pentraxin 3 and the extracellular matrix and modulates complement activation.

    Science.gov (United States)

    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; Józsi, Mihály

    2015-05-15

    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.

  6. Complement and autoimmunity.

    Science.gov (United States)

    Ballanti, Eleonora; Perricone, Carlo; Greco, Elisabetta; Ballanti, Marta; Di Muzio, Gioia; Chimenti, Maria Sole; Perricone, Roberto

    2013-07-01

    The complement system is a component of the innate immune system. Its main function was initially believed to be limited to the recognition and elimination of pathogens through direct killing or stimulation of phagocytosis. However, in recent years, the immunoregulatory functions of the complement system were demonstrated and it was determined that the complement proteins play an important role in modulating adaptive immunity and in bridging innate and adaptive responses. When the delicate mechanisms that regulate this sophisticated enzymatic system are unbalanced, the complement system may cause damage, mediating tissue inflammation. Dysregulation of the complement system has been involved in the pathogenesis and clinical manifestations of several autoimmune diseases, such as systemic lupus erythematosus, vasculitides, Sjögren's syndrome, antiphospholipid syndrome, systemic sclerosis, dermatomyositis, and rheumatoid arthritis. Complement deficiencies have been associated with an increased risk to develop autoimmune disorders. Because of its functions, the complement system is an attractive therapeutic target for a wide range of diseases. Up to date, several compounds interfering with the complement cascade have been studied in experimental models for autoimmune diseases. The main therapeutic strategies are inhibition of complement activation components, inhibition of complement receptors, and inhibition of membrane attack complex. At present, none of the available agents was proven to be both safe and effective for treatment of autoimmune diseases in humans. Nonetheless, data from preclinical studies and initial clinical trials suggest that the modulation of the complement system could constitute a viable strategy for the treatment of autoimmune conditions in the decades to come.

  7. Nebulized C1-Esterase Inhibitor does not Reduce Pulmonary Complement Activation in Rats with Severe Streptococcus Pneumoniae Pneumonia.

    Science.gov (United States)

    de Beer, Friso; Lagrand, Wim; Glas, Gerie J; Beurskens, Charlotte J P; van Mierlo, Gerard; Wouters, Diana; Zeerleder, Sacha; Roelofs, Joris J T H; Juffermans, Nicole P; Horn, Janneke; Schultz, Marcus J

    2016-12-01

    Complement activation plays an important role in the pathogenesis of pneumonia. We hypothesized that inhibition of the complement system in the lungs by repeated treatment with nebulized plasma-derived human C1-esterase inhibitor reduces pulmonary complement activation and subsequently attenuates lung injury and lung inflammation. This was investigated in a rat model of severe Streptococcus pneumoniae pneumonia. Rats were intra-tracheally challenged with S. pneumoniae to induce pneumonia. Nebulized C1-esterase inhibitor or saline (control animals) was repeatedly administered to rats, 30 min before induction of pneumonia and every 6 h thereafter. Rats were sacrificed 20 or 40 h after inoculation with bacteria. Brochoalveolar lavage fluid and lung tissue were obtained for measuring levels of complement activation (C4b/c), lung injury and inflammation. Induction of pneumonia was associated with pulmonary complement activation (C4b/c at 20 h 1.24 % [0.56-2.59] and at 40 h 2.08 % [0.98-5.12], compared to 0.50 % [0.07-0.59] and 0.03 % [0.03-0.03] in the healthy control animals). The functional fraction of C1-INH was detectable in BALF, but no effect was found on pulmonary complement activation (C4b/c at 20 h 0.73 % [0.16-1.93] and at 40 h 2.38 % [0.54-4.19]). Twenty hours after inoculation, nebulized C1-esterase inhibitor treatment reduced total histology score, but this effect was no longer seen at 40 h. Nebulized C1-esterase inhibitor did not affect other markers of lung injury or lung inflammation. In this negative experimental animal study, severe S. pneumoniae pneumonia in rats is associated with pulmonary complement activation. Repeated treatment with nebulized C1-esterase inhibitor, although successfully delivered to the lungs, does not affect pulmonary complement activation, lung inflammation or lung injury.

  8. Humoral pattern recognition and the complement system.

    Science.gov (United States)

    Degn, S E; Thiel, S

    2013-08-01

    In the context of immunity, pattern recognition is the art of discriminating friend from foe and innocuous from noxious. The basis of discrimination is the existence of evolutionarily conserved patterns on microorganisms, which are intrinsic to these microorganisms and necessary for their function and existence. Such immutable or slowly evolving patterns are ideal handles for recognition and have been targeted by early cellular immune defence mechanisms such as Toll-like receptors, NOD-like receptors, RIG-I-like receptors, C-type lectin receptors and by humoral defence mechanisms such as the complement system. Complement is a proteolytic cascade system comprising around 35 different soluble and membrane-bound proteins. It constitutes a central part of the innate immune system, mediating several major innate effector functions and modulating adaptive immune responses. The complement cascade proceeds via controlled, limited proteolysis and conformational changes of constituent proteins through three activation pathways: the classical pathway, the alternative pathway and the lectin pathway, which converge in common effector functions. Here, we review the nature of the pattern recognition molecules involved in complement activation, as well as their close relatives with no or unknown capacity for activating complement. We proceed to examine the composition of the pattern recognition complexes involved in complement activation, focusing on those of the lectin pathway, and arrive at a new model for their mechanism of operation, supported by recently emerging evidence.

  9. Increased complement C4d deposition at the maternal-fetal interface in unexplained recurrent miscarriage

    NARCIS (Netherlands)

    Meuleman, Tess; Cohen, Danielle; Swings, Godelieve M J S; Veraar, Kimberly; Claas, Frans H J; Bloemenkamp, Kitty W M

    2015-01-01

    C4d is a footprint of antibody-mediated classical complement activation, and has evolved as a useful diagnostic marker of antibody-mediated rejection. It is unknown if complement activation, as reflected by C4d deposition plays a role in unexplained recurrent miscarriage. In a case-control study pro

  10. Oral vaccination with heat inactivated Mycobacterium bovis activates the complement system to protect against tuberculosis.

    Directory of Open Access Journals (Sweden)

    Beatriz Beltrán-Beck

    Full Text Available Tuberculosis (TB remains a pandemic affecting billions of people worldwide, thus stressing the need for new vaccines. Defining the correlates of vaccine protection is essential to achieve this goal. In this study, we used the wild boar model for mycobacterial infection and TB to characterize the protective mechanisms elicited by a new heat inactivated Mycobacterium bovis vaccine (IV. Oral vaccination with the IV resulted in significantly lower culture and lesion scores, particularly in the thorax, suggesting that the IV might provide a novel vaccine for TB control with special impact on the prevention of pulmonary disease, which is one of the limitations of current vaccines. Oral vaccination with the IV induced an adaptive antibody response and activation of the innate immune response including the complement component C3 and inflammasome. Mycobacterial DNA/RNA was not involved in inflammasome activation but increased C3 production by a still unknown mechanism. The results also suggested a protective mechanism mediated by the activation of IFN-γ producing CD8+ T cells by MHC I antigen presenting dendritic cells (DCs in response to vaccination with the IV, without a clear role for Th1 CD4+ T cells. These results support a role for DCs in triggering the immune response to the IV through a mechanism similar to the phagocyte response to PAMPs with a central role for C3 in protection against mycobacterial infection. Higher C3 levels may allow increased opsonophagocytosis and effective bacterial clearance, while interfering with CR3-mediated opsonic and nonopsonic phagocytosis of mycobacteria, a process that could be enhanced by specific antibodies against mycobacterial proteins induced by vaccination with the IV. These results suggest that the IV acts through novel mechanisms to protect against TB in wild boar.

  11. Effect of b-Propiolactone treatment on the complement activation mediated by equine antisera

    Directory of Open Access Journals (Sweden)

    Rosalvo GUIDOLIN

    1997-03-01

    Full Text Available Reduction of complement activation through an alteration of the Fc fragment of immunoglobulins by b-propiolactone treatment was carried out in equine antisera raised against rabies virus, Bothrops venoms and diphtherial toxin. Results were evaluated by means of an anaphylactic test performed on guinea-pigs, and compared to the ones obtained with the same sera purified by saline precipitation (ammonium sulfate, followed or not by enzymatic digestion with pepsin. Protein purity levels for antibothropic serum were 184.5 mg/g and 488.5 mg/g in b-propiolactone treated and pepsin-digested sera, respectively. The recovery of specific activity was 100% and 62.5% when using antibothropic serum treated by b-propiolactone and pepsin digestion, respectively. The antidiphtherial and anti-rabies sera treated with b-propiolactone and pepsin presented protein purity levels of 5,698 and 7,179 Lf/g, 16,233 and 6,784 IU/g, respectively. The recovery of specific activity for these antisera were 88.8%, 77.7%, 100% and 36,5%, respectively. b-propiolactone treatment induced a reduction in complement activation, tested "in vivo", without significant loss of biological activity. This treatment can be used in the preparation of heterologous immunoglobulins for human use.Efeito do tratamento de antissoros equinos pela b-propiolactona na ativação do complemento. A redução da ativação do complemento através de uma alteração do fragmento Fc das imunoglobulinas pela b-propiolactona foi obtida em soros hiperimunes equinos antivirus rábico, venenos Bothrops e toxina diftérica. Os resultados foram avaliados por teste de anafilaxia em cobaias, e comparados com aqueles obtidos com os mesmos soros purificados por precipitação salina (sulfato de amônio, seguidos ou não por digestão enzimática com pepsina. Os níveis de pureza protéica foram para o soro antibotrópico de 184.5 mg/g e 488.5 mg/g tratado pela b-propiolactona e digeridos pela pepsina, respectivamente

  12. Neuroprotective effects of intravenous immunoglobulin are mediated through inhibition of complement activation and apoptosis in a rat model of sepsis.

    Science.gov (United States)

    Esen, Figen; Orhun, Gunseli; Ozcan, Perihan Ergin; Senturk, Evren; Kucukerden, Melike; Giris, Murat; Akcan, Ugur; Yilmaz, Canan Ugur; Orhan, Nurcan; Arican, Nadir; Kaya, Mehmet; Gazioglu, Sema Bilgic; Tuzun, Erdem

    2017-12-01

    Intravenous (IV) immunoglobulin (Ig) treatment is known to alleviate behavioral deficits and increase survival in the experimentally induced model of sepsis. To delineate the mechanisms by which IVIg treatment prevents neuronal dysfunction, an array of immunological and apoptosis markers was investigated. Sepsis was induced by cecal ligation perforation (CLP) in rats. The animals were divided into five groups: sham, control, CLP + saline, CLP + immunoglobulin G (IgG) (250 mg/kg, iv), and CLP + immunoglobulins enriched with immunoglobulin M (IgGAM) (250 mg/kg, iv). Blood and brain samples were taken in two sets of experiments to see the early (24 h) and late (10 days) effects of treatment. Total complement activity, complement 3 (C3), and soluble complement C5b-9 levels were measured in the sera of rats using ELISA-based methods. Cerebral complement, complement receptor, NF-κB, Bax, and Bcl-2 expressions were analyzed by western blot and/or RT-PCR methods. Immune cell infiltration and gliosis were examined by immunohistochemistry using CD3, CD4, CD8, CD11b, CD19, and glial fibrillary acidic protein antibodies. Apoptotic neuronal death was investigated by TUNEL staining. IVIgG and IgGAM administration significantly reduced systemic complement activity and cerebral C5a and C5a receptor expression. Likewise, both treatment methods reduced proapoptotic NF-κB and Bax expressions in the brain. IVIgG and IgGAM treatment induced considerable amelioration in glial cell proliferation and neuronal apoptosis which were increased in non-treated septic rats. We suggest that IVIgG and IgGAM administration ameliorates neuronal dysfunction and behavioral deficits by reducing apoptotic cell death and glial cell proliferation. In both treatment methods, these beneficial effects might be mediated through reduction of anaphylatoxic C5a activity and subsequent inhibition of inflammation and apoptosis pathways.

  13. How antibodies use complement to regulate antibody responses.

    Science.gov (United States)

    Sörman, Anna; Zhang, Lu; Ding, Zhoujie; Heyman, Birgitta

    2014-10-01

    Antibodies, forming immune complexes with their specific antigen, can cause complete suppression or several 100-fold enhancement of the antibody response. Immune complexes containing IgG and IgM may activate complement and in such situations also complement components will be part of the immune complex. Here, we review experimental data on how antibodies via the complement system upregulate specific antibody responses. Current data suggest that murine IgG1, IgG2a, and IgG2b upregulate antibody responses primarily via Fc-receptors and not via complement. In contrast, IgM and IgG3 act via complement and require the presence of complement receptors 1 and 2 (CR1/2) expressed on both B cells and follicular dendritic cells. Complement plays a crucial role for antibody responses not only to antigen complexed to antibodies, but also to antigen administered alone. Lack of C1q, but not of Factor B or MBL, severely impairs antibody responses suggesting involvement of the classical pathway. In spite of this, normal antibody responses are found in mice lacking several activators of the classical pathway (complement activating natural IgM, serum amyloid P component (SAP), specific intracellular adhesion molecule-grabbing non-integrin R1 (SIGN-R1) or C-reactive protein. Possible explanations to these observations will be discussed.

  14. Complement system part II: role in immunity

    Directory of Open Access Journals (Sweden)

    Nicolas S. Merle

    2015-05-01

    Full Text Available The complement system has been considered for a long time as a simple lytic system, 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 a direct killing by C5b-9 membrane attack complex by triggering inflammatory responses with the anaphylatoxins C3a and C5a and helps the mounting of an adaptive immune response, involving antigen presenting cells, T- and B- lymphocytes. But it can be also an enemy, when pathogens hijack complement regulators to protect themselves from the immune system. Also examples will be discussed, where inadequate complement activation becomes a disease cause, including atypical hemolytic uremic syndrome (aHUS, C3 glomerulopathies (C3G and systemic lupus erythematosus (SLE. Age related macular degeneration (AMD and cancer will be described as examples showing that complement contributes to a large variety of diseases, far exceeding the classical examples of diseases associated with complement deficiencies. Finally, we discuss complement as a therapeutic target.

  15. Complement System Part II: Role in Immunity

    Science.gov (United States)

    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. Complement activation in coronary artery bypass grafting patients without cardiopulmonary bypass - The role of tissue injury by surgical incision

    NARCIS (Netherlands)

    Gu, YJ; Mariani, MA; Boonstra, PW; Grandjean, JG; van Oeveren, W

    1999-01-01

    Study objectives: Complement activation is a trigger in inducing inflammation in patients who undergo coronary artery bypass grafting (CABG) and is usually thought to be induced by the use of cardiopulmonary bypass (CPB), In this study, we examined whether tissue injury caused by chest surgical inci

  17. A systematic analysis of the complement pathways in patients with neuromyelitis optica indicates alteration but no activation during remission

    DEFF Research Database (Denmark)

    Veszeli, Nóra; Füst, György; Csuka, Dorottya;

    2014-01-01

    Neuromyelitis optica (NMO) is an autoimmune demyelinating inflammatory disorder, mediated by pathogenic autoantibodies against aquaporin 4 (AQP4), the main water channel of the central nervous system (CNS). NMO is characterized by local IgG deposition and complement activation within the CNS...

  18. Complement Activation Is Involved in Renal Damage in Human Antineutrophil Cytoplasmic Autoantibody Associated Pauci-Immune Vasculitis

    NARCIS (Netherlands)

    Xing, Guang-qun; Chen, Min; Liu, Gang; Heeringa, Peter; Zhang, Jun-jun; Zheng, Xin; Jie, E.; Kallenberg, Cees G. M.; Zhao, Ming-hui

    2009-01-01

    This study was to investigate the evidence for complement activation in renal biopsy specimens of patients with myeloperoxidase (MPO)-antineutrophil cytoplasmic autoantibody (ANCA)-associated pauci-immune vasculitis. Renal biopsy specimens from seven patients with MPO-ANCA positive pauci-immune necr

  19. Lectin Pathway of Complement Activation Is Associated with Vulnerability of Atherosclerotic Plaques

    Science.gov (United States)

    Fumagalli, Stefano; Perego, Carlo; Zangari, Rosalia; De Blasio, Daiana; Oggioni, Marco; De Nigris, Francesca; Snider, Francesco; Garred, Peter; Ferrante, Angela M. R.; De Simoni, Maria-Grazia

    2017-01-01

    Inflammatory mechanisms may be involved in atherosclerotic plaque rupture. By using a novel histology-based method to quantify plaque instability here, we assess whether lectin pathway (LP) of complement activation, a major inflammation arm, could represent an index of plaque instability. Plaques from 42 consecutive patients undergoing carotid endarterectomy were stained with hematoxylin-eosin and the lipid core, cholesterol clefts, hemorrhagic content, thickness of tunica media, and intima, including or not infiltration of cellular debris and cholesterol, were determined. The presence of ficolin-1, -2, and -3 and mannose-binding lectin (MBL), LP initiators, was assessed in the plaques by immunofluorescence and in plasma by ELISA. LP activation was assessed in plasma by functional in vitro assays. Patients presenting low stenosis (≤75%) had higher hemorrhagic content than those with high stenosis (>75%), indicating increased erosion. Increased hemorrhagic content and tunica media thickness, as well as decreased lipid core and infiltrated content were associated with vulnerable plaques and therefore used to establish a plaque vulnerability score that allowed to classify patients according to plaque vulnerability. Ficolins and MBL were found both in plaques’ necrotic core and tunica media. Patients with vulnerable plaques showed decreased plasma levels and intraplaque deposition of ficolin-2. Symptomatic patients experiencing a transient ischemic attack had lower plasma levels of ficolin-1. We show that the LP initiators are present within the plaques and their circulating levels change in atherosclerotic patients. In particular, we show that decreased ficolin-2 levels are associated with rupture-prone vulnerable plaques, indicating its potential use as marker for cardiovascular risk assessment in atherosclerotic patients. PMID:28360913

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

    Science.gov (United States)

    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.

  1. Active invasion of Porphyromonas gingivalis and infection-induced complement activation in ApoE-/- mice brains.

    Science.gov (United States)

    Poole, Sophie; Singhrao, Sim K; Chukkapalli, Sasanka; Rivera, Mercedes; Velsko, Irina; Kesavalu, Lakshmyya; Crean, StJohn

    2015-01-01

    Periodontal disease is a polymicrobial inflammatory disease that leads to chronic systemic inflammation and direct infiltration of bacteria/bacterial components, which may contribute to the development of Alzheimer's disease. ApoE-/- mice were orally infected (n = 12) with Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, and Fusobacterium nucleatum as mono- and polymicrobial infections. ApoE-/- mice were sacrificed following 12 and 24 weeks of chronic infection. Bacterial genomic DNA was isolated from all brain tissues except for the F. nucleatum mono-infected group. Polymerase chain reaction was performed using universal 16 s rDNA primers and species-specific primer sets for each organism to determine whether the infecting pathogens accessed the brain. Sequencing amplification products confirmed the invasion of bacteria into the brain during infection. The innate immune responses were detected using antibodies against complement activation products of C3 convertase stage and the membrane attack complex. Molecular methods demonstrated that 6 out of 12 ApoE-/- mice brains contained P. gingivalis genomic DNA at 12 weeks (p = 0.006), and 9 out of 12 at 24 weeks of infection (p = 0.0001). Microglia in both infected and control groups demonstrated strong intracellular labeling with C3 and C9, due to on-going biosynthesis. The pyramidal neurons of the hippocampus in 4 out of 12 infected mice brains demonstrated characteristic opsonization with C3 activation fragments (p = 0.032). These results show that the oral pathogen P. gingivalis was able to access the ApoE-/- mice brain and thereby contributed to complement activation with bystander neuronal injury.

  2. Mechanisms of evasion of Schistosoma mansoni schistosomula to the lethal activity of complement

    Directory of Open Access Journals (Sweden)

    F. Juarez Ramalho-Pinto

    1992-01-01

    Full Text Available Schistosomula of Schistosoma mansoni became resistant to antibody-dependent complement damage in vitro after pre-incubation with normal human erythrocytes (NHuE whatever the ABO or Rh blood group. Resistant parasites were shown to acquire host decay accelerating factor (DAF , a 70 kDa glycoprotein attached to the membrane of NHue by a GPI anchor. IgG2a mAb anti-human DAF (IA10 immunoprecipitated a 70 kDa molecule from 125I-labeled schistosomula pre-incubated with NHuE and inhibited their resistance to complement-dependent killing in vtro. Incubationof schistosomula with erytrocytes from patients with paroxsimal nocturnal hemoglobinuria (PNHE or SRBC, wich are DAF-deficient, did not protect the parasites from complement lesion. Supernatant of 100,000 x g collected from NHuE incubated for 24 h in defined medium was shown to contain a soluble form of DAF and to protect schistosomula from complement killing. Schistosomula treated with trypsin before incubation with NHuE ghosts did not become resistant to complement damage. On the other hand, pre-treatment with chymotrypsin did not interfere with the acquisition of resistance by the schistosomula. These results indicate that, in vitro, NHuE DAF can be transferred to schistosomula in a soluble form and that the binding of this molecule to the parasite surface is dependent upon trypsin-sensitive chymotrypsin-insensitive polipeptide(s present on the surface of the worm.

  3. Study of the variables associated with local complement activation in IgA nephropathy.

    Science.gov (United States)

    Segarra-Medrano, Alfons; Carnicer-Caceres, Clara; Valtierra-Carmeno, Naiara; Agraz-Pamplona, Irene; Ramos-Terrades, Natalia; Jatem Escalante, Elías; Ostos-Roldan, Elena

    1. To identify the variables that are associated with urinary levels of properdin, MBL, C4d, and C5b-9 in patients with idiopathic IgA nephropathy. 2. To analyse whether urinary levels of MBL and/or C4d are useful for identifying the presence of mesangial deposits of C4d/MBL. A total of 96 patients with IgA nephropathy were studied. Demographic, clinical and biochemical variables were recorded at the time of diagnosis. Renal lesions were quantified using the Oxford classification. Immunohistochemical staining for MBL, MASP-2, properdin, C4d, and C5b-9 was performed in kidney biopsies, and in urine, the levels of properdin, MBL, C4d and C5b-9 were determined. In multivariate analysis, the independent predictors of C4d and MBL levels in urine were the mesangial deposits of each protein and, to a lesser extent, the urinary protein excretion. The independent predictors of urinary levels of C5b-9 were MBL properdin and proteinuria. Urinary excretion of C4d had a sensitivity of 90% (95% CI: 58,7 to 99) and a specificity of 73% (95% CI: 54-87) for detecting mesangial C4d deposits, and the level of MBL had a sensitivity of 83.9% (95% CI: 62-95) and a specificity of 81.6% (95% CI: 65-92) for identifying mesangial deposits of MBL. The main predictor of urinary concentration of C4d and MBL was the presence of their respective mesangial deposits. Urine MBL may contribute to complement activation in the tubular luz through the lectin pathway. Urinary levels of MBL and C4d could be sensitive and specific biomarkers for the identification of patients with mesangial deposits of MBL and C4d. Copyright © 2017. Published by Elsevier España, S.L.U.

  4. Immunization with LytB protein of Streptococcus pneumoniae activates complement-mediated phagocytosis and induces protection against pneumonia and sepsis.

    Science.gov (United States)

    Corsini, Bruno; Aguinagalde, Leire; Ruiz, Susana; Domenech, Mirian; Antequera, María Luisa; Fenoll, Asunción; García, Pedro; García, Ernesto; Yuste, Jose

    2016-12-07

    The cell wall glucosaminidase LytB of Streptococcus pneumoniae is a surface exposed protein involved in daughter cell separation, biofilm formation and contributes to different aspects of the pathogenesis process. In this study we have characterized the antibody responses after immunization of mice with LytB in the presence of alhydrogel as an adjuvant. Enzyme-linked immunosorbent assays measuring different subclasses of immunoglobulin G, demonstrated that the antibody responses to LytB were predominantly IgG1 and IgG2b, followed by IgG3 and IgG2a subclasses. Complement-mediated immunity against two different pneumococcal serotypes was investigated using sera from immunized mice. Immunization with LytB increased the recognition of S. pneumoniae by complement components C1q and C3b demonstrating that anti-LytB antibodies trigger activation of the classical pathway. Phagocytosis assays showed that serum containing antibodies to LytB stimulates neutrophil-mediated phagocytosis against S. pneumoniae. Animal models of infection including invasive pneumonia and sepsis were performed with two different clinical isolates. Vaccination with LytB increased bacterial clearance and induced protection demonstrating that LytB might be a good candidate to be considered in a future protein-based vaccine against S. pneumoniae.

  5. The Lectin Pathway of Complement and Biocompatibility

    DEFF Research Database (Denmark)

    Hein, Estrid; Garred, Peter

    2015-01-01

    In modern health technologies the use of biomaterials in the form of stents, haemodialysis tubes, artificial implants, bypass circuits etc. is rapidly expanding. The exposure of synthetic, foreign surfaces to the blood and tissue of the host, calls for strict biocompatibility in respect to contac...... been broadly documented. However, the specific role of lectin pathway and the pattern recognition molecules initiating the pathway has only been transiently investigated. Here we review the current data on the field....... activation, the coagulation system and the complement system. The complement system is an important part of the initial immune response and consists of fluid phase molecules in the blood stream. Three different activation pathways can initiate the complement system, the lectin, the classical...

  6. Teaching Statistics Using Classic Psychology Research: An Activities-Based Approach

    Science.gov (United States)

    Holmes, Karen Y.; Dodd, Brett A.

    2012-01-01

    In this article, we discuss a collection of active learning activities derived from classic psychology studies that illustrate the appropriate use of descriptive and inferential statistics. (Contains 2 tables.)

  7. Substituting complements

    OpenAIRE

    Dari-Mattiacci, G.; Parisi, F.; Heller, M.

    2009-01-01

    The presence of multiple sellers in the provision of (nonsubstitutable) complementary goods leads to outcomes that are worse than those generated by a monopoly (with a vertically integrated production of complements), a problem known in the economic literature as complementary oligopoly and recently popularized in the legal literature as the tragedy of the anticommons. We ask the following question: how many substitutes for each complement are necessary to render the presence of multiple sell...

  8. Ficolin-3-mediated lectin complement pathway activation in patients with subarachnoid hemorrhage

    DEFF Research Database (Denmark)

    Zanier, Elisa R; Zangari, Rosalia; Munthe-Fog, Lea

    2014-01-01

    OBJECTIVES: To assess the involvement of ficolin-3, the main initiator of the lectin complement pathway (LCP), in subarachnoid hemorrhage (SAH) pathology and outcome. METHODS: In this preliminary exploratory study, plasma concentration of ficolin-3 and of ficolin-3-mediated functional LCP activit...

  9. Zinc supplementation inhibits complement activation in age-related macular degeneration

    NARCIS (Netherlands)

    Smailhodzic, D.; Asten, F. van; Blom, A.M.; Mohlin, F.C.; Hollander, A.I. den; Ven, J.P.H. van de; Huet, R.A.C. van; Groenewoud, J.M.M.; Tian, Y.; Berendschot, T.T.; Lechanteur, Y.T.E.; Fauser, S.; Bruijn, C. de; Daha, M.R.; Wilt, G.J. van der; Hoyng, C.B.; Klevering, B.J.

    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

  10. Aluminum hydroxide adjuvant differentially activates the three complement pathways with major involvement of the alternative pathway

    DEFF Research Database (Denmark)

    Güven, Esin; Duus, Karen; Laursen, Inga

    2013-01-01

    Al(OH)3 is the most common adjuvant in human vaccines, but its mode of action remains poorly understood. Complement involvement in the adjuvant properties of Al(OH)3 has been suggested in several reports together with a depot effect. It is here confirmed that Al(OH)3 treatment of serum depletes c...

  11. Distinct Polymer Architecture Mediates Switching of Complement Activation Pathways at the Nanosphere-Serum Interface: Implications for Stealth Nanoparticle Engineering

    DEFF Research Database (Denmark)

    Hamad, I.; Al-Hanbali, O.; Hunter, A.C.

    2010-01-01

    Nanoparticles with surface projected polyethyleneoxide (PEO) chains in 'mushroom-brush' and "brush" configurations display stealth properties in systemic circulation and have numerous applications in site specific targeting for controlled drug delivery and release as well as diagnostic Imaging. We...... reactions in some individuals Conformational states of surface chains, arising from the block copolymer poloxamine 908 adsorption, on polystyrene nanoparticles trigger complement activation differently. Alteration of copolymer architecture on nanospheres from mushroom to brush configuration not only....... Notably, the role properdin mediated activation of alternative pathway was only restricted to particles displaying PEO chains in a transition mushroom-brush configuration Since nanoparticle-mediated complement activation is of clinical concern our findings provide a rational basis for improved surface...

  12. Activation of Human Complement System by Dextran-Coated Iron Oxide Nanoparticles Is Not Affected by Dextran/Fe Ratio, Hydroxyl Modifications, and Crosslinking

    DEFF Research Database (Denmark)

    Wang, Guankui; Chen, Fangfang; Banda, Nirmal K

    2016-01-01

    While having tremendous potential as therapeutic and imaging tools, the clinical use of engineered nanoparticles has been associated with serious safety concerns. Activation of the complement cascade and the release of proinflammatory factors C3a and C5a may contribute to infusion-related reactions......, whereas opsonization with C3 fragments promotes rapid recognition and clearance of nanomaterials by mononuclear phagocytes. We used dextran-coated superparamagnetic iron oxide nanoparticles (SPIO), which are potent activators of the complement system, to study the role of nanoparticle surface chemistry...... in inciting complement in human serum. Using complement inhibitors and measuring levels of fluid phase markers (sC5b-9, C5a, and Bb), we found that the majority of human complement activation by SPIO is through the alternative pathways (AP). SPIO prepared with high dextran/iron ratio showed some complement...

  13. Complement analysis 2016: Clinical indications, laboratory diagnostics and quality control.

    Science.gov (United States)

    Prohászka, Zoltán; Nilsson, Bo; Frazer-Abel, Ashley; Kirschfink, Michael

    2016-11-01

    In recent years, complement analysis of body fluids and biopsies, going far beyond C3 and C4, has significantly enhanced our understanding of the disease process. Such expanded complement analysis allows for a more precise differential diagnosis and for critical monitoring of complement-targeted therapy. These changes are a result of the growing understanding of the involvement of complement in a diverse set of disorders. To appreciate the importance of proper complement analysis, it is important to understand the role it plays in disease. Historically, it was the absence of complement as manifested in severe infection that was noted. Since then complement has been connected to a variety of inflammatory disorders, such as autoimmune diseases and hereditary angioedema. While the role of complement in the rejection of renal grafts has been known longer, the significant impact of complement. In certain nephropathies has now led to the reclassification of some rare kidney diseases and an increased role for complement analysis in diagnosis. Even more unexpected is that complement has also been implicated in neural, ophtalmological and dermatological disorders. With this level of involvement in some varied and impactful health issues proper complement testing is clearly important; however, analysis of the complement system varies widely among laboratories. Except for a few proteins, such as C3 and C4, there are neither well-characterized standard preparations nor calibrated assays available. This is especially true for the inter-laboratory variation of tests which assess classical, alternative, or lectin pathway function. In addition, there is a need for the standardization of the measurement of complement activation products that are so critical in determining whether clinically relevant complement activation has occurred in vivo. Finally, autoantibodies to complement proteins (e.g. anti-C1q), C3 and C4 convertases (C3 and C4 nephritic factor) or to regulatory proteins

  14. Endothelial targeting with C1-inhibitor reduces complement activation in vitro and during ex vivo reperfusion of pig liver.

    Science.gov (United States)

    Bergamaschini, L; Gobbo, G; Gatti, S; Caccamo, L; Prato, P; Maggioni, M; Braidotti, P; Di Stefano, R; Fassati, L R

    2001-12-01

    Tissue damage during cold storage and reperfusion remains a major obstacle to wider use of transplantation. Vascular endothelial cells and complement activation are thought to be involved in the inflammatory reactions following reperfusion, so endothelial targeting of complement inhibitors is of great interest. Using an in vitro model of human umbilical vein endothelial cells (HUVEC) cold storage and an animal model of ex vivo liver reperfusion after cold ischaemia, we assessed the effect of C1-INH on cell functions and liver damage. We found that in vitro C1-INH bound to HUVEC in a manner depending on the duration of cold storage. Cell-bound C1-INH was functionally active since retained the ability to inhibit exogenous C1s. To assess the ability of cell-bound C1-INH to prevent complement activation during organ reperfusion, we added C1-INH to the preservation solution in an animal model of extracorporeal liver reperfusion. Ex vivo liver reperfusion after 8 h of cold ischaemia resulted in plasma C3 activation and reduction of total serum haemolytic activity, and at tissue level deposition of C3 associated with variable level of inflammatory cell infiltration and tissue damage. These findings were reduced when livers were stored in preservation solution containing C1-INH. Immunohistochemical analysis of C1-INH-treated livers showed immunoreactivity localized on the sinusoidal pole of the liver trabeculae, linked to sinusoidal endothelium, so it is likely that the protective effect was due to C1-INH retained by the livers. These results suggest that adding C1-INH to the preservation solution may be useful to reduce complement activation and tissue injury during the reperfusion of an ischaemic liver.

  15. Complement in hemolytic anemia.

    Science.gov (United States)

    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.

  16. A novel trifunctional IgG-like bispecific antibody to inhibit HIV-1 infection and enhance lysis of HIV by targeting activation of complement

    Directory of Open Access Journals (Sweden)

    Tomlinson Stephen

    2010-06-01

    Full Text Available Abstract Background The complement system is not only a key component of innate immunity but also provides a first line of defense against invading pathogens, especially for viral pathogens. Human immunodeficiency virus (HIV, however, possesses several mechanisms to evade complement-mediated lysis (CoML and exploit the complement system to enhance viral infectivity. Responsible for this intrinsic resistance against complement-mediated virolysis are complement regulatory membrane proteins derived from the host cell that inherently downregulates complement activation at several stages of the cascade. In addition, HIV is protected from complement-mediated lysis by binding soluble factor H (fH through the viral envelope proteins, gp120 and gp41. Whereas inhibition of complement activity is the desired outcome in the vast majority of therapeutic approaches, there is a broader potential for complement-mediated inhibition of HIV by complement local stimulation. Presentation of the hypothesis Our previous studies have proven that the complement-mediated antibody-dependent enhancement of HIV infection is mediated by the association of complement receptor type 2 bound to the C3 fragment and deposited on the surface of HIV virions. Thus, we hypothesize that another new activator of complement, consisting of two dsFv (against gp120 and against C3d respectively linked to a complement-activating human IgG1 Fc domain ((anti-gp120 × anti-C3d-Fc, can not only target and amplify complement activation on HIV virions for enhancing the efficiency of HIV lysis, but also reduce the infectivity of HIV through blocking the gp120 and C3d on the surface of HIV. Testing the hypothesis Our hypothesis was tested using cell-free HIV-1 virions cultivated in vitro and assessment of virus opsonization was performed by incubating appropriate dilutions of virus with medium containing normal human serum and purified (anti-gp120 × anti-C3d-Fc proteins. As a control group, viruses

  17. Heterocomplexes of mannose-binding lectin and the pentraxins PTX3 or SAP trigger cross-activation of the complement system

    DEFF Research Database (Denmark)

    Ma, Ying Jie; Doni, Andrea; Skjødt, Mikkel-Ole;

    2011-01-01

    The long pentraxin 3 (PTX3), serum amyloid P component (SAP) and C-reactive protein (CRP) belong to the pentraxin family of pattern recognition molecules involved in tissue homeostasis and innate immunity. They interact with C1q from the classical complement pathway. Whether this also occurs via...... the analogous mannose-binding lectin (MBL) from the lectin complement pathway is unknown. Thus, we investigated the possible interaction between MBL and the pentraxins. We report that MBL bound PTX3 and SAP partly via its collagen-like domain, but not CRP. MBL:PTX3 complex formation resulted in recruitment of C......1q, but this was not seen for the MBL:SAP complex. However, both MBL:PTX3 and MBL:SAP complexes enhanced C4 and C3 deposition and opsonophagocytosis of Candida albicans by polymorphonuclear leukocytes. Interaction between MBL and PTX3 lead to communication between the lectin and classical complement...

  18. Exploring the potential benefits of vaccinia virus complement control protein in controlling complement activation in pathogenesis of the central nervous system diseases.

    Science.gov (United States)

    Kotwal, Girish J; Fernando, Nilisha; Zhou, Jianhua; Valter, Krisztina

    2014-10-01

    Aging is a major risk factor for the development of diseases related to the central nervous system (CNS), such as Alzheimer's disease (AD) and age-related macular degeneration (AMD). In both cases, linkage studies and genome-wide association studies found strong links with complement regulatory genes and disease risk. In AD, both CLU and CR1 genes were implicated in the late-onset form of the disease. In AMD, polymorphisms in CFH, CFB and C2 were similarly implicated. The cost of caring for patients with AD or AMD is approaching billions of dollars, and with the baby boomers reaching their 60's, this amount is likely to increase further. Intervention using complement inhibitors for individuals in their early 50s who are at a higher risk of disease development, (testing positive for genetic risk factors), could slow the progression of AD or AMD and possibly prevent the severity of late stage symptoms. Although we have used the vaccinia virus complement control protein (VCP) to elucidate the role of complement in CNS diseases, it has merely been an investigational tool but not the only possible potential therapeutic agent.

  19. Complement and membrane-bound complement regulatory proteins as biomarkers and therapeutic targets for autoimmune inflammatory disorders, RA and SLE.

    Science.gov (United States)

    Das, Nibhriti

    2015-11-01

    Complement system is a major effecter system of the innate immunity that bridges with adaptive immunity. The system consists of about 40 humoral and cell surface proteins that include zymogens, receptors and regulators. The zymogens get activated in a cascade fashion by antigen-antibody complex, antigen alone or by polymannans, respectively, by the classical, alternative and mannose binding lectin (MBL) pathways. The ongoing research on complement regulators and complement receptors suggest key role of these proteins in the initiation, regulation and effecter mechanisms of the innate and adaptive immunity. Although, the complement system provides the first line of defence against the invading pathogens, its aberrant uncontrolled activation causes extensive self tissue injury. A large number of humoral and cell surface complement regulatory protein keep the system well-regulated in healthy individuals. Complement profiling had brought important information on the pathophysiology of several infectious and chronic inflammatory disorders. In view of the diversity of the clinical disorders involving abnormal complement activity or regulation, which include both acute and chronic diseases that affect a wide range of organs, diverse yet specifically tailored therapeutic approaches may be needed to shift complement back into balance. This brief review discusses on the complement system, its functions and its importance as biomarkers and therapeutic targets for autoimmune diseases with focus on SLE and RA.

  20. A Gammaherpesvirus Complement Regulatory Protein Promotes Initiation of Infection by Activation of Protein Kinase Akt/PKB

    Science.gov (United States)

    Steer, Beatrix; Adler, Barbara; Jonjic, Stipan; Stewart, James P.; Adler, Heiko

    2010-01-01

    Background Viruses have evolved to evade the host's complement system. The open reading frames 4 (ORF4) of gammaherpesviruses encode homologs of regulators of complement activation (RCA) proteins, which inhibit complement activation at the level of C3 and C4 deposition. Besides complement regulation, these proteins are involved in heparan sulfate and glycosaminoglycan binding, and in case of MHV-68, also in viral DNA synthesis in macrophages. Methodology/Principal Findings Here, we made use of MHV-68 to study the role of ORF4 during infection of fibroblasts. While attachment and penetration of virions lacking the RCA protein were not affected, we observed a delayed delivery of the viral genome to the nucleus of infected cells. Analysis of the phosphorylation status of a variety of kinases revealed a significant reduction in phosphorylation of the protein kinase Akt in cells infected with ORF4 mutant virus, when compared to cells infected with wt virus. Consistent with a role of Akt activation in initial stages of infection, inhibition of Akt signaling in wt virus infected cells resulted in a phenotype resembling the phenotype of the ORF4 mutant virus, and activation of Akt by addition of insulin partially reversed the phenotype of the ORF4 mutant virus. Importantly, the homologous ORF4 of KSHV was able to rescue the phenotype of the MHV-68 ORF4 mutant, indicating that ORF4 is functionally conserved and that ORF4 of KSHV might have a similar function in infection initiation. Conclusions/Significance In summary, our studies demonstrate that ORF4 contributes to efficient infection by activation of the protein kinase Akt and thus reveal a novel function of a gammaherpesvirus RCA protein. PMID:20657771

  1. Leakage of protein into lungs of preterm ventilated rabbits is correlated with activation of clotting, complement, and polymorphonuclear leukocytes in plasma

    NARCIS (Netherlands)

    Brus, F; vanOeveren, W; Heikamp, A; Okken, A; Oetomo, SB

    We investigated whether leakage of protein in lungs of pre term ventilated rabbits of 28- and 29-d gestational age is correlated with activation of clotting, complement, and polymorphonuclear leukocytes (PMN) in plasma. We found signs of systemic activation of clotting, complement, and PMN in

  2. Leakage of protein into lungs of preterm ventilated rabbits is correlated with activation of clotting, complement, and polymorphonuclear leukocytes in plasma

    NARCIS (Netherlands)

    Brus, F; vanOeveren, W; Heikamp, A; Okken, A; Oetomo, SB

    1996-01-01

    We investigated whether leakage of protein in lungs of pre term ventilated rabbits of 28- and 29-d gestational age is correlated with activation of clotting, complement, and polymorphonuclear leukocytes (PMN) in plasma. We found signs of systemic activation of clotting, complement, and PMN in ventil

  3. Effect of IL-4 on altered expression of complement activation regulators in rat pancreatic cells during severe acute pancreatitis

    Institute of Scientific and Technical Information of China (English)

    Cheng Zhang; Chun-Lin Ge; Ren-Xuan Guo; San-Guang He

    2005-01-01

    AIM: To investigate the effect of IL-4 on the altered expression of complement activation regulators in pancreas and pancreatic necrosis during experimental severe acute pancreatitis (SAP).METHODS: SAP model of rats was established by retrograde injection of 5% sodium taurocholate (1 mL/kg)into the pancreatic duct. We immunohistochemically assayed the expression of three complement activation regulators: decay accelerating factor (DAF; CD55), 20ku homologous restriction factor (HRF20; CD59) and membrane cofactor protein (MCP; CD46), in the pancreatic acinar cells of rats at 0, 3, 6, 12, and 24 h after the induction of SAP model. Meanwhile the levels of amylase and lipase were determined, and morphological examination was performed. Then, 61 rats were randomly divided into three groups. Group A (n = 21) received notreatment after the SAP model was established; group B (n = 20) was given IL-4 (8 μg/animal) intraperitoneally 0.5 h before the SAP model was established; group C (n = 20) was given IL-4 (8 μg/animal) intraperitoneally 0.5 h after the SAP model was established. Plasma amylase and lipase, extent of pancreatic necrosis and expression of complement activation regulators were investigated 6 h after the induction of SAP model.RESULTS: Three complement activation regulators were all expressed in pancreatic acinar cells. MCP was not found on the basolateral surface as reported. Contrary to the gradually increasing plasma level of amylase and lipase, expression of complement activation regulators decreased after SAP model was set up. At the same time, the severity of pancreatic necrosis was enhanced.A strong negative correlation was found between the expression of MCP, DAF, CD59 in pancreatic acinar cells and the severity of pancreatic necrosis (r = -0.748, -0.827,-0.723; P<0.01). In the second series of experiments,no matter when the treatment of IL-4 was given (before or after the induction of SAP model), the serum level of amylase or lipase Was decreased

  4. Complement activating soluble pattern recognition molecules with collagen-like regions, mannan-binding lectin, ficolins and associated proteins

    DEFF Research Database (Denmark)

    Thiel, Steffen

    2007-01-01

    Mannan-binding lectin (MBL), L-ficolin, M-ficolin and H-ficolin are all complement activating soluble pattern recognition molecules with recognition domains linked to collagen-like regions. All four may form complexes with four structurally related proteins, the three MBL-associated serine...... proteases (MASPs), MASP-1, MASP-2 and MASP-3, and a smaller MBL-associated protein (MAp19). The four recognition molecules recognize patterns of carbohydrate or acetyl-group containing ligands. After binding to the relevant targets all four are able to activate the complement system. We thus have a system...... where four different and/or overlapping patterns of microbial origin or patterns of altered-self may be recognized, but in all cases the signalling molecules, the MASPs, are shared. MASP-1 and MASP-3 are formed from one gene, MASP1/3, by alternative splicing generating two different mRNAs from a single...

  5. Retinal pigment epithelial cells upregulate expression of complement factors after co-culture with activated T cells

    DEFF Research Database (Denmark)

    Juel, Helene Bæk; Kaestel, Charlotte; Folkersen, Lasse

    2011-01-01

    In this study we examined the effect of T cell-derived cytokines on retinal pigment epithelial (RPE) cells with respect to expression of complement components. We used an in vitro co-culture system in which CD3/CD28-activated human T cells were separated from the human RPE cell line (ARPE-19) by ...... of inflammatory ocular diseases such as uveitis and age-related macular degeneration. --------------------------------------------------------------------------------...

  6. Complement-Mediated Glomerular Diseases: A Tale of 3 Pathways

    Directory of Open Access Journals (Sweden)

    Andrew S. Bomback

    2016-09-01

    Full Text Available A renewed interest in the role of complement in the pathogenesis of glomerular diseases has improved our understanding of their basic, underlying physiology. All 3 complement pathways—classical, lectin, and alternative—have been implicated in glomerular lesions both rare (e.g., dense deposit disease and common (e.g., IgA nephropathy. Here we review the basic function of these pathways and highlight, with a disease-specific focus, how activation can lead to glomerular injury. We end by exploring the promise of complement-targeted therapies as disease-specific interventions for glomerular diseases.

  7. In Situ complement activation and T-cell immunity in leprosy spectrum: An immunohistological study on leprosy lesional skin.

    Science.gov (United States)

    Bahia El Idrissi, Nawal; Iyer, Anand M; Ramaglia, Valeria; Rosa, Patricia S; Soares, Cleverson T; Baas, Frank; Das, Pranab K

    2017-01-01

    Mycobacterium leprae (M. leprae) infection causes nerve damage and the condition worsens often during and long after treatment. Clearance of bacterial antigens including lipoarabinomannan (LAM) during and after treatment in leprosy patients is slow. We previously demonstrated that M. leprae LAM damages peripheral nerves by in situ generation of the membrane attack complex (MAC). Investigating the role of complement activation in skin lesions of leprosy patients might provide insight into the dynamics of in situ immune reactivity and the destructive pathology of M. leprae. In this study, we analyzed in skin lesions of leprosy patients, whether M. leprae antigen LAM deposition correlates with the deposition of complement activation products MAC and C3d on nerves and cells in the surrounding tissue. Skin biopsies of paucibacillary (n = 7), multibacillary leprosy patients (n = 7), and patients with erythema nodosum leprosum (ENL) (n = 6) or reversal reaction (RR) (n = 4) and controls (n = 5) were analyzed. The percentage of C3d, MAC and LAM deposition was significantly higher in the skin biopsies of multibacillary compared to paucibacillary patients (p = leprosy patients (r = 0.9578, pleprosy patients (p = leprosy patients, suggesting that inflammation driven by complement activation might contribute to nerve damage in the lesions of these patients. This should be regarded as an important factor in M. leprae nerve damage pathology.

  8. FRAGMENT Bb: EVIDENCE FOR ACTIVATION OF THE ALTERNATIVE PATHWAY OF THE COMPLEMENT SYSTEM IN PREGNANT WOMEN WITH ACUTE PYELONEPHRITIS

    Science.gov (United States)

    Soto, Eleazar; Romero, Roberto; Vaisbuch, Edi; Erez, Offer; Mazaki-Tovi, Shali; Kusanovic, Juan Pedro; Dong, Zhong; Chaiworapongsa, Tinnakorn; Yeo, Lami; Mittal, Pooja; Hassan, Sonia S.

    2010-01-01

    OBJECTIVE Pyelonephritis during pregnancy is associated with a more severe course than in the non-pregnant state. This has been attributed to an increased susceptibility of pregnant women to microbial products. The complement system is part of innate immunity and its alternative pathway is activated mainly by microorganisms. The purpose of this study was to determine if activation of the alternative pathway of the complement system (determined by maternal fragment Bb concentrations) occurs in pregnant women with acute pyelonephritis. METHODS This cross-sectional study included the following groups: 1) normal pregnant women (n=62); and 2) pregnant women with pyelonephritis (n=38). Maternal plasma Fragment Bb concentrations were determined by ELISA. Non-parametric statistics were used for analyses. RESULTS 1) Pregnant women with pyelonephritis had a higher median plasma concentration of fragment Bb than those with a normal pregnancy (1.3 μg/ml, IQR: 1.1-1.9 vs. 0.8 μg/m, IQR: 0.7-0.9; ppyelonephritis who had a positive blood culture and those with a negative blood culture (1.4 μg/ml, IQR: 1.1-3.5 vs. 1.3 μg/ml, IQR: 1.1-1.9; p=0.2). CONCLUSIONS Pregnant women with acute pyelonephritis have evidence of activation of the alternative pathway of the complement system, regardless of the presence or absence of a positive blood culture. PMID:20218820

  9. Therapeutic complement inhibition in complement-mediated hemolytic anemias: Past, present and future.

    Science.gov (United States)

    Risitano, Antonio M; Marotta, Serena

    2016-06-01

    The introduction in the clinic of anti-complement agents represented a major achievement which gave to physicians a novel etiologic treatment for different human diseases. Indeed, the first anti-complement agent eculizumab has changed the treatment paradigm of paroxysmal nocturnal hemoglobinuria (PNH), dramatically impacting its severe clinical course. In addition, eculizumab is the first agent approved for atypical Hemolytic Uremic Syndrome (aHUS), a life-threatening inherited thrombotic microangiopathy. Nevertheless, such remarkable milestone in medicine has brought to the fore additional challenges for the scientific community. Indeed, the list of complement-mediated anemias is not limited to PNH and aHUS, and other human diseases can be considered for anti-complement treatment. They include other thrombotic microangiopathies, as well as some antibody-mediated hemolytic anemias. Furthermore, more than ten years of experience with eculizumab led to a better understanding of the individual steps of the complement cascade involved in the pathophysiology of different human diseases. Based on this, new unmet clinical needs are emerging; a number of different strategies are currently under development to improve current anti-complement treatment, trying to address these specific clinical needs. They include: (i) alternative anti-C5 agents, which may improve the heaviness of eculizumab treatment; (ii) broad-spectrum anti-C3 agents, which may improve the efficacy of anti-C5 treatment by intercepting the complement cascade upstream (i.e., preventing C3-mediated extravascular hemolysis in PNH); (iii) targeted inhibitors of selective complement activating pathways, which may prevent early pathogenic events of specific human diseases (e.g., anti-classical pathway for antibody-mediated anemias, or anti-alternative pathway for PNH and aHUS). Here we briefly summarize the status of art of current and future complement inhibition for different complement-mediated anemias

  10. The Role of Complement System in Septic Shock

    Directory of Open Access Journals (Sweden)

    Jean Charchaflieh

    2012-01-01

    Full Text Available Septic shock is a critical clinical condition with a high mortality rate. A better understanding of the underlying mechanisms is important to develop effective therapies. Basic and clinical studies suggest that activation of complements in the common cascade, for example, complement component 3 (C3 and C5, is involved in the development of septic shock. The involvement of three upstream complement pathways in septic shock is more complicated. Both the classical and alternative pathways appear to be activated in septic shock, but the alternative pathway may be activated earlier than the classical pathway. Activation of these two pathways is essential to clear endotoxin. Recent investigations have shed light on the role of lectin complement pathway in septic shock. Published reports suggest a protective role of mannose-binding lectin (MBL against sepsis. Our preliminary study of MBL-associated serine protease-2 (MASP-2 in septic shock patients indicated that acute decrease of MASP-2 in the early phase of septic shock might correlate with in-hospital mortality. It is unknown whether excessive activation of these three upstream complement pathways may contribute to the detrimental effects in septic shock. This paper also discusses additional complement-related pathogenic mechanisms and intervention strategies for septic shock.

  11. Classical Flutter and Active Control of Wind Turbine Blade Based on Piezoelectric Actuation

    Directory of Open Access Journals (Sweden)

    Tingrui Liu

    2015-01-01

    Full Text Available The aim of this article is to analyze classical flutter and active control of single-cell thin-walled composite wind turbine blade beam based on piezoelectric actuation. Effects of piezoelectric actuation for classical flutter suppression on wind turbine blade beam subjected to combined transverse shear deformation, warping restraint effect, and secondary warping are investigated. The extended Hamilton’s principle is used to set up the equations of motion, and the Galerkin method is applied to reduce the aeroelastic coupled equations into a state-space form. Active control is developed to enhance the vibrational behavior and dynamic response to classical aerodynamic excitation and stabilize structures that might be damaged in the absence of control. Active optimal control scheme based on linear quadratic Gaussian (LQG controller is implemented. The research provides a way for rare study of classical flutter suppression and active control of wind turbine blade based on piezoelectric actuation.

  12. The Classical and Regulatory Functions of C1q in Immunity and Autoimmunity

    Institute of Scientific and Technical Information of China (English)

    Jinhua Lu; Boon King Teh; Linda Wang; Yinan Wang; Yen Seah Tan; Min Chern Lai; Kenneth B.M.Reid

    2008-01-01

    A classical function of Clq is to bind immune complexes and initiate complement activation producing membrane lytic complexes. opsonins and anaphylatoxins. This classical pathway of complement activation is also elicited when Clq binds some other ligands. Besides complement activation, Clq also regulates cell differentiation, adhesion, migration. activation and survival. Clq deficiency is associated with autoimmunity as well as increased susceptibility to infections. In this article. we discuss the basic properties of Clq, its expression, and classical and regulatory functions. Cellular & Molecular Immunology.2008;5(1):9-21.

  13. Complement regulators in human disease: lessons from modern genetics.

    Science.gov (United States)

    K Liszewski, M; Atkinson, J P

    2015-03-01

    First identified in human serum in the late 19th century as a 'complement' to antibodies in mediating bacterial lysis, the complement system emerged more than a billion years ago probably as the first humoral immune system. The contemporary complement system consists of nearly 60 proteins in three activation pathways (classical, alternative and lectin) and a terminal cytolytic pathway common to all. Modern molecular biology and genetics have not only led to further elucidation of the structure of complement system components, but have also revealed function-altering rare variants and common polymorphisms, particularly in regulators of the alternative pathway, that predispose to human disease by creating 'hyperinflammatory complement phenotypes'. To treat these 'complementopathies', a monoclonal antibody against the initiator of the membrane attack complex, C5, has received approval for use. Additional therapeutic reagents are on the horizon.

  14. A novel peptide can mimic extracellular fibrinogen-binding protein to block the activation of complement system.

    Science.gov (United States)

    Gao, Ya-ping; Dong, Jie; Zhang, Xin; Liu, Yu; Lu, Qiang; Feng, Jian-nan; Tan, Xiao-rong; Yang, Guang

    2013-07-01

    Extracellular fibrinogen-binding protein (Efb) of Staphylococcus aureus (S. aureus) is a bi-functional protein, which can specifically bind fibrinogen with its N terminus and inhibit deposition of C3b on the surface of S. aureus with its C terminus. Here, we screened the epitopes of Efb using phage display. Four peptides with consensus motif were screened. This consensus motif was identical to C terminus (161-164) of Efb. In the further investigation, it was found the synthesized peptide EC1 (154-165aa of Efb) could specifically bind C3/C3b and subsequently to block the activation of complement. Meanwhile, EC1 could inhibit the interaction between Efb and C3/C3b. Moreover, the interaction between the mutant protein of EmC1 (Efb without EC1) and C3 was decreased. And, the effect on the complement system of the mutant protein was dramatically declined compared with Efb. Our finding suggested that the peptide EC1 could mimic Efb to block complement system activation via binding C3.

  15. Substituting complements

    NARCIS (Netherlands)

    G. Dari-Mattiacci; F. Parisi

    2006-01-01

    The presence of multiple sellers in the provision of (nonsubstitutable) complementary goods leads to outcomes that are worse than those generated by a monopoly (with a vertically integrated production of complements), a problem known in the economic literature as complementary oligopoly and recently

  16. Substituting complements

    NARCIS (Netherlands)

    G. Dari-Mattiacci; F. Parisi

    2009-01-01

    The presence of multiple sellers in the provision of (nonsubstitutable) complementary goods leads to outcomes that are worse than those generated by a monopoly (with a vertically integrated production of complements), a problem known in the economic literature as complementary oligopoly and recently

  17. New perspectives on mannan-binding lectin-mediated complement activation

    DEFF Research Database (Denmark)

    Degn, Søren Egedal; Thiel, Steffen; Jensenius, Jens Christian

    2007-01-01

    is the most recently discovered, and least characterized. The CP and the LP are generally viewed as working through the generation of the C3 convertase, C4bC2b, and are here referred to as the "standard" pathways. In addition to the standard CP and LP, so-called bypass pathways have also been reported...... picture of the complement system is more that of a small "scale-free" network where C3 acts as the main hub, than that of three linear pathways converging in a common terminal pathway....

  18. Up-Regulated Production and Activation of the Complement System in Alzheimer’s Disease Brain

    OpenAIRE

    Yasojima, Koji; Schwab, Claudia; McGeer, Edith G.; McGeer, Patrick L.

    1999-01-01

    We used reverse transcriptase-polymerase chain reaction and Western blotting techniques to measure the levels of complement mRNAs and their protein products in Alzheimer’s disease (AD) brain compared with non-AD brain. mRNAs for C1q, C1r, C1s, C2, C3, C4, C5, C6, C7, C8, and C9 were detected in the 11 regions of brain that were investigated. The mRNA levels were markedly up-regulated in affected areas of AD brain. In the entorhinal cortex, hippocampus, and midtemporal gyrus, which had dense a...

  19. Bacterial DNA induces the complement system activation in serum and ascitic fluid from patients with advanced cirrhosis.

    Science.gov (United States)

    Francés, Rubén; González-Navajas, José M; Zapater, Pedro; Muñoz, Carlos; Caño, Rocío; Pascual, Sonia; Márquez, Dorkas; Santana, Francia; Pérez-Mateo, Miguel; Such, José

    2007-07-01

    Translocation of intestinal bacteria to ascitic fluid is, probably, the first step in the development of spontaneous bacterial peritonitis in patients with cirrhosis. Proteins of the complement system are soluble mediators implicated in the host immune response to bacterial infections and its activation has been traditionally considered to be an endotoxin-induced phenomenon. The aim of this study was to compare the modulation of these proteins in response to the presence of bacterial DNA and/or endotoxin in patients with advanced cirrhosis and ascites in different clinical conditions. Groups I and II consisted of patients without/with bacterial DNA. Group III included patients with spontaneous bacterial peritonitis and Group IV with patients receiving norfloxacin as secondary long-term prophylaxis of spontaneous bacterial peritonitis. Serum and ascitic fluid levels of endotoxin and truncated residues of the complement system were measured by ELISA. The complement system is triggered in response to bacterial DNA, as evidenced by significantly increased levels of C3b, membrane attack complex, and C5a in patients from Groups II and III compared with patients without bacterial DNA (Group I) and those receiving norfloxacin (Group IV). Gram classification did not further differentiate the immune response between patients within groups II and III, even though endotoxin levels were, as expected, significantly higher in patients with bacterial DNA from gram-negative microorganisms. The complement protein activation observed in patients with bacterial DNA in blood and ascitic fluid is indistinguishable from that observed in patients with spontaneous bacterial peritonitis and may occur in an endotoxin-independent manner.

  20. Complement activation as a bioequivalence issue relevant to the development of generic liposomes and other nanoparticulate drugs

    Energy Technology Data Exchange (ETDEWEB)

    Szebeni, Janos, E-mail: jszebeni2@gmail.com [Nanomedicine Research and Education Center, Semmelweis University, Budapest & SeroScience Ltd, Budapest (Hungary); Storm, Gert [Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht (Netherlands)

    2015-12-18

    Liposomes are known to activate the complement (C) system, which can lead in vivo to a hypersensitivity syndrome called C activation-related pseudoallergy (CARPA). CARPA has been getting increasing attention as a safety risk of i.v. therapy with liposomes, whose testing is now recommended in bioequivalence evaluations of generic liposomal drug candidates. This review highlights the adverse consequences of C activation, the unique symptoms of CARPA triggered by essentially all i.v. administered liposomal drugs, and the various features of vesicles influencing this adverse immune effect. For the case of Doxil, we also address the mechanism of C activation and the opsonization vs. long circulation (stealth) paradox. In reviewing the methods of assessing C activation and CARPA, we delineate the most sensitive porcine model and an algorithm for stepwise evaluation of the CARPA risk of i.v. liposomes, which are proposed for standardization for preclinical toxicology evaluation of liposomal and other nanoparticulate drug candidates. - Highlights: • Outlining of difficulties in generic development of liposomal drugs. • New regulatory requirements to evaluate CARPA in preclinical studies. • Review of complement activation by liposomes and its adverse consequences (CARPA). • Assays of C activation in vitro and CARPA in vivo, with the porcine test in focus. • Decision tree how to handle the risk of CARPA assessed by a battery of tests.

  1. Structural features and complement-fixing activity of pectin from three Brassica oleracea varieties: white cabbage, kale, and red kale.

    Science.gov (United States)

    Samuelsen, Anne Berit; Westereng, Bjørge; Yousif, Osman; Holtekjølen, Ann Katrin; Michaelsen, Terje E; Knutsen, Svein H

    2007-02-01

    Leaves of different cabbage species are used both as food and as wound healing remedies in traditional medicine. This supposed wound healing activity might be connected to presence of immunomodulating water soluble polysaccharides. To study this, three different cabbage varieties, white cabbage (W), kale (K), and red kale (RK), were pretreated with 80% ethanol and then extracted with water at 50 degrees C and 100 degrees C for isolation of polysaccharide-containing fractions. The fractions were analyzed for monosaccharide composition, glycosidic linkages, Mw distribution, protein content, and phenolic compounds and then tested for complement-fixing activity. All fractions contained pectin type polysaccharides with linkages corresponding to homogalacturonan and hairy regions. Those extracted at 50 degrees C contained higher amounts of neutral side chains and were more active in the complement-fixation test than those extracted at 100 degrees C. The fractions can be ranged by decreasing activity: K-50 > RK-50 > W-50 approximately = K-100 > RK100 approximately = W-100. Studies on structure-activity relationships (SAR) employing multivariate statistical analysis strongly suggest that the magnitude of the measured activity is influenced by the content of certain side chains in the polymers. High activity correlates to large neutral side chains with high amounts of (1-->6)- and (1-->3,6)-linked Gal and low amounts of (1-->4)-linked GalA but not on molecular weight distribution of the polymers.

  2. Crosstalk between complement and Toll-like receptor activation in relation to donor brain death and renal ischemia-reperfusion injury.

    Science.gov (United States)

    Damman, Jeffrey; Daha, Mohamed R; van Son, Willem J; Leuvenink, Henri G; Ploeg, Rutger J; Seelen, Marc A

    2011-04-01

    Two central pathways of innate immunity, complement and Toll-like receptors (TLRs), play an important role in the pathogenesis of renal injury inherent to kidney transplantation. Recent findings indicate close crosstalk between complement and TLR signaling pathways. It is suggested that mitogen activated protein kinases (MAPKs) might be the key molecules linking both the complement and TLR pathways together. Complement and TLRs are important mediators of renal ischemia-reperfusion injury (IRI). Besides IRI, complement C3 can also be upregulated and activated in the kidney before transplantation as a direct result of brain death (BD) in the donor. This local upregulation and activation of complement in the donor kidney has been proven to be detrimental for renal allograft outcome. Also TLR4 and several of its major ligands are upregulated by donor BD compared to living donors. Important and in line with the observations above, kidney transplant recipients have a benefit when receiving a kidney from a TLR4 Asp299Gly/Thr399Ile genotypic donor. The role of complement and TLRs and crosstalk between these two innate immune systems in relation to renal injury during donor BD and ischemia-reperfusion are focus of this review. Future strategies to target complement and TLR activation in kidney transplantation are considered.

  3. Human factor H-related protein 2 (CFHR2 regulates complement activation.

    Directory of Open Access Journals (Sweden)

    Hannes U Eberhardt

    Full Text Available Mutations and deletions within the human CFHR gene cluster on chromosome 1 are associated with diseases, such as dense deposit disease, CFHR nephropathy or age-related macular degeneration. Resulting mutant CFHR proteins can affect complement regulation. Here we identify human CFHR2 as a novel alternative pathway complement regulator that inhibits the C3 alternative pathway convertase and terminal pathway assembly. CFHR2 is composed of four short consensus repeat domains (SCRs. Two CFHR2 molecules form a dimer through their N-terminal SCRs, and each of the two C-terminal ends can bind C3b. C3b bound CFHR2 still allows C3 convertase formation but the CFHR2 bound convertases do not cleave the substrate C3. Interestingly CFHR2 hardly competes off factor H from C3b. Thus CFHR2 likely acts in concert with factor H, as CFHR2 inhibits convertases while simultaneously allowing factor H assisted degradation by factor I.

  4. Serum amyloid P component bound to gram-negative bacteria prevents lipopolysaccharide-mediated classical pathway complement activation

    NARCIS (Netherlands)

    de Haas, CJC; van Leeuwen, EMM; van Bommel, T; Verhoef, J; van Kessel, KPM; van Strijp, JAG

    Although serum amyloid P component (SAP) is known to bind many ligands, its biological function is not yet clear. Recently, it was demonstrated that SAP binds to lipopolysaccharide (LPS), In the present study, SAP was shown to bind to gram-negative bacteria expressing short types of LPS or

  5. Serum amyloid P component bound to gram-negative bacteria prevents lipopolysaccharide-mediated classical pathway complement activation

    NARCIS (Netherlands)

    de Haas, CJC; van Leeuwen, EMM; van Bommel, T; Verhoef, J; van Kessel, KPM; van Strijp, JAG

    2000-01-01

    Although serum amyloid P component (SAP) is known to bind many ligands, its biological function is not yet clear. Recently, it was demonstrated that SAP binds to lipopolysaccharide (LPS), In the present study, SAP was shown to bind to gram-negative bacteria expressing short types of LPS or lipo-olig

  6. Seroprevalence of Antibody-Mediated, Complement-Dependent Opsonophagocytic Activity against Neisseria meningitidis Serogroup B in England.

    Science.gov (United States)

    Humphries, Holly E; Brookes, Charlotte; Allen, Lauren; Kuisma, Eeva; Gorringe, Andrew; Taylor, Stephen

    2015-05-01

    The correlate of protection for the licensure of meningococcal vaccines is serum bactericidal activity. However, evidence indicates that a complex situation and other mechanisms, such as antibody-mediated, complement-dependent opsonophagocytosis (OP), may play a role in protection and should be investigated in order to understand immunity to this disease. In this study, a high-throughput flow cytometric opsonophagocytic assay (OPA) was optimized. The assay measures the presence of killed fluorescently labeled Neisseria meningitidis within human granulocytes (differentiated HL60 cells) by flow cytometry, using IgG-depleted pooled human plasma as an exogenous source of complement. This method was found to be reliable and correlated with the results of an opsonophagocytic killing assay. The OPA was used to measure OP activity in 1,878 serum samples from individuals ranging from 0 to 99 years of age against N. meningitidis strain NZ98/254 (B:4:P1.7-2,4). The levels of OP activity in individual serum samples varied greatly. OP activity showed an initial peak in the 6- to 12-month age group corresponding to a peak in disease incidence. The OP activity dropped in childhood until the late teenage years, although there was still a higher percentage of individuals with OP activity than with protective bactericidal antibody titers. OP activity reached a peak in the 30- to 39-year age group and then declined. This later peak in OP activity did not coincide with the young adults in whom peak serum bactericidal activity and disease incidence occurred. The demonstration of OP activity when disease incidence is low and when protective bactericidal antibody titers are not detected may indicate a role for OP in protection from meningococcal disease in these age groups.

  7. Hippocampal unit activity during classical aversive and appetitive conditioning.

    Science.gov (United States)

    Segal, M; Disterhoft, J F; Olds, J

    1972-02-18

    Rats were trained with a tone being followed by either food or electric shock, on alternate days. Unit activity during application of the conditioned stimulus was recorded from the dorsal hippocampus. The results indicate differentiation of the hippocampal system. Dentate units respond by augmentation to a conditioned stimulus which leads to food and by inhibition to the same stimulus when it precedes electric shock. The hippocampus proper responds by augmentation in both situations. The intensity of the hippocampal response to the conditioned stimulus on the first day of training is higher if the unconditioned stimulus is food than if it is electric shock. These data cast light on the functions of the dorsal dentate-hippocampal connections and the hippocampus proper during aversive and appetitive conditioning.

  8. Microglia, Alzheimer's Disease, and Complement

    Directory of Open Access Journals (Sweden)

    Helen Crehan

    2012-01-01

    Full Text Available Microglia, the immune cell of the brain, are implicated in cascades leading to neuronal loss and cognitive decline in Alzheimer’s disease (AD. Recent genome-wide association studies have indicated a number of risk factors for the development of late-onset AD. Two of these risk factors are an altered immune response and polymorphisms in complement receptor 1. In view of these findings, we discuss how complement signalling in the AD brain and microglial responses in AD intersect. Dysregulation of the complement cascade, either by changes in receptor expression, enhanced activation of different complement pathways or imbalances between complement factor production and complement cascade inhibitors may all contribute to the involvement of complement in AD. Altered complement signalling may reduce the ability of microglia to phagocytose apoptotic cells and clear amyloid beta peptides, modulate the expression by microglia of complement components and receptors, promote complement factor production by plaque-associated cytokines derived from activated microglia and astrocytes, and disrupt complement inhibitor production. The evidence presented here indicates that microglia in AD are influenced by complement factors to adopt protective or harmful phenotypes and the challenge ahead lies in understanding how this can be manipulated to therapeutic advantage to treat late onset AD.

  9. Complement genetics, deficiencies, and disease associations.

    Science.gov (United States)

    Mayilyan, Karine R

    2012-07-01

    The complement system is a key component of innate immunity. More than 45 genes encoding the proteins of complement components or their isotypes and subunits, receptors, and regulators have been discovered. These genes are distributed throughout different chromosomes, with 19 genes comprising three significant complement gene clusters in the human genome. Genetic deficiency of any early component of the classical pathway (C1q, C1r/s, C2, C4, and C3) is associated with autoimmune diseases due to the failure of clearance of immune complexes (IC) and apoptotic materials, and the impairment of normal humoral response. Deficiencies of mannan-binding lectin (MBL) and the early components of the alternative (factor D, properdin) and terminal pathways (from C3 onward components: C5, C6, C7, C8, C9) increase susceptibility to infections and their recurrence. While the association of MBL deficiency with a number of autoimmune and infectious disorders has been well established, the effects of the deficiency of other lectin pathway components (ficolins, MASPs) have been less extensively investigated due to our incomplete knowledge of the genetic background of such deficiencies and the functional activity of those components. For complement regulators and receptors, the consequences of their genetic deficiency vary depending on their specific involvement in the regulatory or signalling steps within the complement cascade and beyond. This article reviews current knowledge and concepts about the genetic load of complement component deficiencies and their association with diseases. An integrative presentation of genetic data with the latest updates provides a background to further investigations of the disease association investigations of the complement system from the perspective of systems biology and systems genetics.

  10. Plasma thymus and activation-regulated chemokine as an early response marker in classical Hodgkin's lymphoma

    NARCIS (Netherlands)

    Plattel, Wouter J.; van den Berg, Anke; Visser, Lydia; van der Graaf, Anne-Marijn; Pruim, Jan; Vos, Hans; Hepkema, Bouke; Diepstra, Arjan; van Imhoff, Gustaaf W.

    2012-01-01

    BACKGROUND: Plasma thymus and activation-regulated chemokine is a potential biomarker for classical Hodgkin's lymphoma. To define its value as a marker to monitor treatment response, we correlated serial plasma thymus and activation-regulated chemokine levels with clinical response in newly diagnose

  11. Lack of predictability of classical animal models for hypolipidemic activity: A good time for mice?

    NARCIS (Netherlands)

    Krause, B.R.; Princen, H.M.G.

    1998-01-01

    Hypolipidemic drugs that are efficacious in man are not always active in classical animal models of dyslipidemia. Inhibitors of HMG-CoA reductase (statins) do not lower plasma cholesterol in rats, but yet this species was alone in providing activity for fibrate-type drugs. Nicotinic acid possesses m

  12. Keeping It All Going-Complement Meets Metabolism.

    Science.gov (United States)

    Kolev, Martin; Kemper, Claudia

    2017-01-01

    The complement system is an evolutionary old and crucial component of innate immunity, which is key to the detection and removal of invading pathogens. It was initially discovered as a liver-derived sentinel system circulating in serum, the lymph, and interstitial fluids that mediate the opsonization and lytic killing of bacteria, fungi, and viruses and the initiation of the general inflammatory responses. Although work performed specifically in the last five decades identified complement also as a critical instructor of adaptive immunity-indicating that complement's function is likely broader than initially anticipated-the dominant opinion among researchers and clinicians was that the key complement functions were in principle defined. However, there is now a growing realization that complement activity goes well beyond "classic" immune functions and that this system is also required for normal (neuronal) development and activity and general cell and tissue integrity and homeostasis. Furthermore, the recent discovery that complement activation is not confined to the extracellular space but occurs within cells led to the surprising understanding that complement is involved in the regulation of basic processes of the cell, particularly those of metabolic nature-mostly via novel crosstalks between complement and intracellular sensor, and effector, pathways that had been overlooked because of their spatial separation. These paradigm shifts in the field led to a renaissance in complement research and provide new platforms to now better understand the molecular pathways underlying the wide-reaching effects of complement functions in immunity and beyond. In this review, we will cover the current knowledge about complement's emerging relationship with the cellular metabolism machinery with a focus on the functional differences between serum-circulating versus intracellularly active complement during normal cell survival and induction of effector functions. We will also

  13. Elevated Properdin and Enhanced Complement Activation in First-Degree Relatives of South Asian Subjects With Type 2 Diabetes

    Science.gov (United States)

    Somani, Riyaz; Richardson, Victoria R.; Standeven, Kristina F.; Grant, Peter J.; Carter, Angela M.

    2012-01-01

    OBJECTIVE Emerging data implicate activation of the complement cascade in the pathogenesis of type 2 diabetes. The objective of the current study was to evaluate the relationships between components of the complement system, metabolic risk factors, and family history of type 2 diabetes in healthy South Asians. RESEARCH DESIGN AND METHODS We recruited 119 healthy, first-degree relatives of South Asian subjects with type 2 diabetes (SARs) and 119 age- and sex-matched, healthy South Asian control subjects (SACs). Fasting blood samples were taken for measurement of complement factors and standard metabolic risk factors. RESULTS SARs were characterized by significantly higher properdin (mean concentration 12.6 [95% CI 12.2–13.1] mg/L vs. SACs 10.1 [9.7–10.5] mg/L, P < 0.0001), factor B (187.4 [180.1–195.0] mg/L vs. SACs 165.0 [158.0–172.2] mg/L, P < 0.0001), and SC5b-9 (92.0 [86.1–98.3] ng/mL vs. SACs 75.3 [71.9–78.9] ng/mL, P < 0.0001) and increased homeostasis model assessment of insulin resistance (2.86 [2.61–3.13] vs. SACs 2.31 [2.05–2.61], P = 0.007). C-reactive protein did not differ between SARs and SACs (P = 0.17). In subgroup analysis of 25 SARs and 25 SACs with normal oral glucose tolerance tests, properdin, factor B, and SC5b-9 remained significantly elevated in SARs. CONCLUSIONS Increased properdin and complement activation are associated with a family history of type 2 diabetes in South Asians independent of insulin resistance, and predate the development of impaired fasting glucose and impaired glucose tolerance. Properdin and SC5b-9 may be novel biomarkers for future risk of type 2 diabetes in this high-risk population and warrant further investigation. PMID:22338105

  14. Complement activation-related pseudoallergy in dogs following intravenous administration of a liposomal formulation of meglumine antimoniate

    Directory of Open Access Journals (Sweden)

    Raul R. Ribeiro

    2013-08-01

    Full Text Available The increasing use of nanotechnologies in advanced therapies has allowed the observation of specific adverse reactions related to nanostructures. The toxicity of a novel liposome formulation of meglumine antimoniate in dogs with visceral leishmaniasis after single dose has been investigated. Groups of 12 animals received by the intravenous route a single dose of liposomal meglumine antimoniate (group I [GI], 6.5 mg Sb/kg, empty liposomes (GII or isotonic saline (GIII. Evaluation of hematological and biochemical parameters showed no significant changes 4 days after administration. No undesired effects were registered in the GIII. However, adverse reactions were observed in 67.7% of dogs from both groups that received liposomal formulations. The side effects began moments after bolus administration and disappeared during the first 15 minutes after treatment. Prostation, sialorrhea and defecation were the most frequent clinical signs, registered in 33.3% and 41.6 % of animals from the groups GI and GII, respectively. Tachypnea, mydriasis, miosis, vomiting and cyanosis were also registered in both groups. The adverse reactions observed in this study were attributed to the activation of the complement system by lipid vesicles in a phenomenon known as Complement Activation-Related Pseudoallergy (CARPA. The influence of the physical-chemical characteristics of liposomal formulation in the triggering of CARPA is discussed.

  15. Plasma-derived human C1-esterase inhibitor does not prevent mechanical ventilation-induced pulmonary complement activation in a rat model of Streptococcus pneumoniae pneumonia.

    Science.gov (United States)

    de Beer, F M; Aslami, H; Hoeksma, J; van Mierlo, G; Wouters, D; Zeerleder, S; Roelofs, J J T H; Juffermans, N P; Schultz, M J; Lagrand, W K

    2014-11-01

    Mechanical ventilation has the potential to cause lung injury, and the role of complement activation herein is uncertain. We hypothesized that inhibition of the complement cascade by administration of plasma-derived human C1-esterase inhibitor (C1-INH) prevents ventilation-induced pulmonary complement activation, and as such attenuates lung inflammation and lung injury in a rat model of Streptococcus pneumoniae pneumonia. Forty hours after intratracheal challenge with S. pneumoniae causing pneumonia rats were subjected to ventilation with lower tidal volumes and positive end-expiratory pressure (PEEP) or high tidal volumes without PEEP, after an intravenous bolus of C1-INH (200 U/kg) or placebo (saline). After 4 h of ventilation blood, broncho-alveolar lavage fluid and lung tissue were collected. Non-ventilated rats with S. pneumoniae pneumonia served as controls. While ventilation with lower tidal volumes and PEEP slightly amplified pneumonia-induced complement activation in the lungs, ventilation with higher tidal volumes without PEEP augmented local complement activation more strongly. Systemic pre-treatment with C1-INH, however, failed to alter ventilation-induced complement activation with both ventilation strategies. In accordance, lung inflammation and lung injury were not affected by pre-treatment with C1-INH, neither in rats ventilated with lower tidal volumes and PEEP, nor rats ventilated with high tidal volumes without PEEP. Ventilation augments pulmonary complement activation in a rat model of S. pneumoniae pneumonia. Systemic administration of C1-INH, however, does not attenuate ventilation-induced complement activation, lung inflammation, and lung injury.

  16. Soluble Collectin-12 (CL-12) Is a Pattern Recognition Molecule Initiating Complement Activation via the Alternative Pathway.

    Science.gov (United States)

    Ma, Ying Jie; Hein, Estrid; Munthe-Fog, Lea; Skjoedt, Mikkel-Ole; Bayarri-Olmos, Rafael; Romani, Luigina; Garred, Peter

    2015-10-01

    Soluble defense collagens including the collectins play important roles in innate immunity. Recently, a new member of the collectin family named collectin-12 (CL-12 or CL-P1) has been identified. CL-12 is highly expressed in umbilical cord vascular endothelial cells as a transmembrane receptor and may recognize certain bacteria and fungi, leading to opsonophagocytosis. However, based on its structural and functional similarities with soluble collectins, we hypothesized the existence of a fluid-phase analog of CL-12 released from cells, which may function as a soluble pattern-recognition molecule. Using recombinant CL-12 full length or CL-12 extracellular domain, we determined the occurrence of soluble CL-12 shed from in vitro cultured cells. Western blot showed that soluble recombinant CL-12 migrated with a band corresponding to ∼ 120 kDa under reducing conditions, whereas under nonreducing conditions it presented multimeric assembly forms. Immunoprecipitation and Western blot analysis of human umbilical cord plasma enabled identification of a natural soluble form of CL-12 having an electrophoretic mobility pattern close to that of shed soluble recombinant CL-12. Soluble CL-12 could recognize Aspergillus fumigatus partially through the carbohydrate-recognition domain in a Ca(2+)-independent manner. This led to activation of the alternative pathway of complement exclusively via association with properdin on A. fumigatus as validated by detection of C3b deposition and formation of the terminal complement complex. These results demonstrate the existence of CL-12 in a soluble form and indicate a novel mechanism by which the alternative pathway of complement may be triggered directly by a soluble pattern-recognition molecule.

  17. Complement activating antibodies to myelin oligodendrocyte glycoprotein in neuromyelitis optica and related disorders

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    Mader Simone

    2011-12-01

    Full Text Available Abstract Background Serum autoantibodies against the water channel aquaporin-4 (AQP4 are important diagnostic biomarkers and pathogenic factors for neuromyelitis optica (NMO. However, AQP4-IgG are absent in 5-40% of all NMO patients and the target of the autoimmune response in these patients is unknown. Since recent studies indicate that autoimmune responses to myelin oligodendrocyte glycoprotein (MOG can induce an NMO-like disease in experimental animal models, we speculate that MOG might be an autoantigen in AQP4-IgG seronegative NMO. Although high-titer autoantibodies to human native MOG were mainly detected in a subgroup of pediatric acute disseminated encephalomyelitis (ADEM and multiple sclerosis (MS patients, their role in NMO and High-risk NMO (HR-NMO; recurrent optic neuritis-rON or longitudinally extensive transverse myelitis-LETM remains unresolved. Results We analyzed patients with definite NMO (n = 45, HR-NMO (n = 53, ADEM (n = 33, clinically isolated syndromes presenting with myelitis or optic neuritis (CIS, n = 32, MS (n = 71 and controls (n = 101; 24 other neurological diseases-OND, 27 systemic lupus erythematosus-SLE and 50 healthy subjects for serum IgG to MOG and AQP4. Furthermore, we investigated whether these antibodies can mediate complement dependent cytotoxicity (CDC. AQP4-IgG was found in patients with NMO (n = 43, 96%, HR-NMO (n = 32, 60% and in one CIS patient (3%, but was absent in ADEM, MS and controls. High-titer MOG-IgG was found in patients with ADEM (n = 14, 42%, NMO (n = 3, 7%, HR-NMO (n = 7, 13%, 5 rON and 2 LETM, CIS (n = 2, 6%, MS (n = 2, 3% and controls (n = 3, 3%, two SLE and one OND. Two of the three MOG-IgG positive NMO patients and all seven MOG-IgG positive HR-NMO patients were negative for AQP4-IgG. Thus, MOG-IgG were found in both AQP4-IgG seronegative NMO patients and seven of 21 (33% AQP4-IgG negative HR-NMO patients. Antibodies to MOG and AQP4 were predominantly of the IgG1 subtype, and were able

  18. Clinical significance of complement as a biomarker of disease activity in 4 cases of IgG4-related disease with retroperitoneal fibrosis.

    Science.gov (United States)

    Kihara, Mari; Sugihara, Takahiko; Hosoya, Tadashi; Miyasaka, Nobuyuki

    2013-01-01

    Hypocomplementaemia is frequently observed in IgG4-related diseases, however the clinical significance is unclear. We describe herein the clinical courses of 4 patients with IgG4-related disease with hypocomplementaemia. Our cases showed autoimmune pancreatitis, retroperitoneal fibrosis, Mikulicz's disease, interstitial lung disease, lymphadenopathy and mesenteric fibrosis around the aorta. A decrease in serum complement preceded deterioration of the disease and clinical improvement was observed in accordance with normalisation of serum complement. These clinical courses suggest that serum complement is a biomarker of the disease activity.

  19. Effect of honey on 50% complement hemolytic activity in infants with protein energy malnutrition: a randomized controlled pilot study.

    Science.gov (United States)

    Abdulrhman, Mamdouh Abdulmaksoud; Nassar, May Fouad; Mostafa, Hisham Waheed; El-Khayat, Zakaria Abdulhalim; Abu El Naga, Marwa Wageh

    2011-05-01

    Protein energy malnutrition (PEM) is associated with a significant impairment of cell-mediated immunity and complement system, which may be responsible for the high incidence of infections among these patients. This study was designed to examine the effect of honey, as a natural substance, on the 50% complement hemolytic activity (CH50) in patients with PEM. Thirty patients with PEM and 20 healthy infants serving as controls participated in this study. The patients were randomized to receive either honey (group 1) or placebo (group 2), in addition to conventional nutritional rehabilitation therapy. Measurements of weight, midarm circumference, skin fold thickness, serum albumin, and CH50 were done for all patients before and after 2 weeks of rehabilitation. Before nutritional rehabilitation, the CH50 was significantly lower in the PEM groups compared with the control. However, after rehabilitation, the CH50 increased significantly in both PEM groups, compared with the pre-interventional state and with the controls. Moreover, the rise of CH50 was significantly more in the honey group compared with the placebo. On the other hand, the improvement in the anthropometric measures and serum albumin did not differ significantly between the honey and placebo groups after rehabilitation. Thus honey supplementation in patients with PEM increased the level of CH50. Whether this would have an effect on the frequency and severity of infections in patients with PEM needs further studies.

  20. Meningococcal surface fibril (Msf) binds to activated vitronectin and inhibits the terminal complement pathway to increase serum resistance.

    Science.gov (United States)

    Griffiths, Natalie J; Hill, Darryl J; Borodina, Elena; Sessions, Richard B; Devos, Nathalie I; Feron, Christiane M; Poolman, Jan T; Virji, Mumtaz

    2011-12-01

    Complement evasion is an important survival strategy of Neisseria meningitidis (Nm) during colonization and infection. Previously, we have shown that Nm Opc binds to serum vitronectin to inhibit complement-mediated killing. In this study, we demonstrate meningococcal interactions with vitronectin via a novel adhesin, Msf (meningococcal surface fibril, previously NhhA or Hsf). As with Opc, Msf binds preferentially to activated vitronectin (aVn), engaging at its N-terminal region but the C-terminal heparin binding domain may also participate. However, unlike Opc, the latter binding is not heparin-mediated. By binding to aVn, Msf or Opc can impart serum resistance, which is further increased in coexpressers, a phenomenon dependent on serum aVn concentrations. The survival fitness of aVn-binding derivatives was evident from mixed population studies, in which msf/opc mutants were preferentially depleted. In addition, using vitronectin peptides to block Msf-aVn interactions, aVn-induced inhibition of lytic C5b-9 formation and of serum killing could be reversed. As Msf-encoding gene is ubiquitous in the meningococcal strains examined and is expressed in vivo, serum resistance via Msf may be of significance to meningococcal pathogenesis. The data imply that vitronectin binding may be an important strategy for the in vivo survival of Nm for which the bacterium has evolved redundant mechanisms.

  1. Interactions of PLGA nanoparticles with blood components: protein adsorption, coagulation, activation of the complement system and hemolysis studies

    Science.gov (United States)

    Fornaguera, Cristina; Calderó, Gabriela; Mitjans, Montserrat; Vinardell, Maria Pilar; Solans, Conxita; Vauthier, Christine

    2015-03-01

    The intravenous administration of poly(lactic-co-glycolic) acid (PLGA) nanoparticles has been widely reported as a promising alternative for delivery of drugs to specific cells. However, studies on their interaction with diverse blood components using different techniques are still lacking. Therefore, in the present work, the interaction of PLGA nanoparticles with blood components was described using different complementary techniques. The influence of different encapsulated compounds/functionalizing agents on these interactions was also reported. It is worth noting that all these techniques can be simply performed, without the need for highly sophisticated apparatus or skills. Moreover, their transference to industries and application of quality control could be easily performed. Serum albumin was adsorbed onto all types of tested nanoparticles. The saturation concentration was dependent on the nanoparticle size. In contrast, fibrinogen aggregation was dependent on nanoparticle surface charge. The complement activation was also influenced by the nanoparticle functionalization; the presence of a functionalizing agent increased complement activation, while the addition of an encapsulated compound only caused a slight increase. None of the nanoparticles influenced the coagulation cascade at low concentrations. However, at high concentrations, cationized nanoparticles did activate the coagulation cascade. Interactions of nanoparticles with erythrocytes did not reveal any hemolysis. Interactions of PLGA nanoparticles with blood proteins depended both on the nanoparticle properties and the protein studied. Independent of their loading/surface functionalization, PLGA nanoparticles did not influence the coagulation cascade and did not induce hemolysis of erythrocytes; they could be defined as safe concerning induction of embolization and cell lysis.The intravenous administration of poly(lactic-co-glycolic) acid (PLGA) nanoparticles has been widely reported as a promising

  2. Tumour exosomes display differential mechanical and complement activation properties dependent on malignant state: implications in endothelial leakiness

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    Bradley Whitehead

    2015-12-01

    Full Text Available Background: Exosomes have been implicated in tumour progression and metastatic spread. Little is known of the effect of mechanical and innate immune interactions of malignant cell-derived exosomes on endothelial integrity, which may relate to increased extravasation of circulating tumour cells and, therefore, increased metastatic spread. Methods: Exosomes isolated from non-malignant immortalized HCV-29 and isogenic malignant non-metastatic T24 and malignant metastatic FL3 bladder cells were characterized by nanoparticle tracking analysis and quantitative nanomechanical mapping atomic force microscopy (QNM AFM to determine size and nanomechanical properties. Effect of HCV-29, T24 and FL3 exosomes on human umbilical vein endothelial cell (HUVEC monolayer integrity was determined by transendothelial electrical resistance (TEER measurements and transport was determined by flow cytometry. Complement activation studies in human serum of malignant and non-malignant cell-derived exosomes were performed. Results: FL3, T24 and HCV-29 cells produced exosomes at similar concentration per cell (6.64, 6.61 and 6.46×104 exosomes per cell for FL3, T24 and HCV-29 cells, respectively and of similar size (120.2 nm for FL3, 127.6 nm for T24 and 117.9 nm for HCV-29, respectively. T24 and FL3 cell-derived exosomes exhibited a markedly reduced stiffness, 95 MPa and 280 MPa, respectively, compared with 1,527 MPa with non-malignant HCV-29 cell-derived exosomes determined by QNM AFM. FL3 and T24 exosomes induced endothelial disruption as measured by a decrease in TEER in HUVEC monolayers, whereas no effect was observed for HCV-29 derived exosomes. FL3 and T24 exosomes traffic more readily (11.6 and 21.4% of applied exosomes, respectively across HUVEC monolayers than HCV-29 derived exosomes (7.2% of applied exosomes. Malignant cell-derived exosomes activated complement through calcium-sensitive pathways in a concentration-dependent manner. Conclusions: Malignant

  3. Exciting New Take on a Classic: Crash Testing Activity Puts the Egg in the Driver's Seat

    Science.gov (United States)

    Board, Keith

    2011-01-01

    An excellent common activity in technology and engineering classes involves dropping an egg from a significant height in a protective device designed and built by students. This article describes how the author uses the classic "egg drop" as an inspiration to have students modify a small crash test vehicle that speeds down a track and crashes into…

  4. Exciting New Take on a Classic: Crash Test Activity Puts the Egg in the Driver's Seat

    Science.gov (United States)

    Board, Keith

    2011-01-01

    An excellent common activity in technology and engineering classes involves dropping an egg from a significant height in a protective device designed and built by students. This article describes how the author uses the classic "egg drop" as an inspiration to have students modify a small crash test vehicle that speeds down a track and crashes into…

  5. Generalization of the Activated Complex Theory of Reaction Rates. II. Classical Mechanical Treatment

    Science.gov (United States)

    Marcus, R. A.

    1964-01-01

    In its usual classical form activated complex theory assumes a particular expression for the kinetic energy of the reacting system -- one associated with a rectilinear motion along the reaction coordinate. The derivation of the rate expression given in the present paper is based on the general kinetic energy expression.

  6. Complement-mediated neutrophil activation in sepsis- and trauma-related adult respiratory distress syndrome. Clarification with radioaerosol lung scans

    Energy Technology Data Exchange (ETDEWEB)

    Tennenberg, S.D.; Jacobs, M.P.; Solomkin, J.S.

    1987-01-01

    Complement-mediated neutrophil activation (CMNA) has been proposed as an important pathogenic mechanism causing acute microvascular lung injury in the adult respiratory distress syndrome (ARDS). To clarify the relationship between CMNA and evolving lung injury, we studied 26 patients with multiple trauma and sepsis within 24 hours of risk establishment for ARDS. Pulmonary alveolar-capillary permeability (PACP) was quantified as the clearance rate of a particulate radioaerosol. Seventeen patients (65%) had increased PACP (six developed ARDS) while nine (35%) had normal PACP (none developed ARDS; clearance rates of 3.4%/min and 1.5%/min, respectively). These patients, regardless of evidence of early lung injury, had elevated plasma C3adesArg levels and neutrophil chemotactic desensitization to C5a/C5adesArg. Plasma C3adesArg levels correlated weakly, but significantly, with PACP. Thus, CMNA may be a necessary, but not a sufficient, pathogenic mechanism in the evolution of ARDS.

  7. Effect of Asparagus polysaccharide on the number and activity of erythrocyte complement receptor 1 (CD35) of S180 mice

    Institute of Scientific and Technical Information of China (English)

    JI Yu-bin; MIN Yong-cui; JI Chen-feng

    2008-01-01

    Objective To study the effect of Asparagus officinalis polysaccharide on the number and activity of erythroeyte complement receptor 1 in S180 mice. Methods Red blood cells from mice venous blood were labeled by rat anti-mouse CD35 monoclonal antibody and FITC-conjugated goat anti-mouse antibody. Using flow cytometry, we determined the number of ECR1. Using microscope, we studied the adherence between erythrocyte immunity and C3b receptor or tumor-cell by RBC-C3bRR and DTER. Results Comparing the mean value of the number of CR1 on each RBC of high and middle groups with control groups, the mean value of the number of CR1, RBC-C3bRR and DTER of Asparagus officinalis polysaccharide groups are increased significantly. Conclusions Asparagus officinalis polysaccharide can improve the erythrocyte function of S180 mice, which may be one of its most important antitumor mechanisms.

  8. Mangiferin inhibits macrophage classical activation via downregulating interferon regulatory factor 5 expression.

    Science.gov (United States)

    Wei, Zhiquan; Yan, Li; Chen, Yixin; Bao, Chuanhong; Deng, Jing; Deng, Jiagang

    2016-08-01

    Mangiferin is a natural polyphenol and the predominant effective component of Mangifera indica Linn. leaves. For hundreds of years, Mangifera indica Linn. leaf has been used as an ingredient in numerous traditional Chinese medicine preparations for the treatment of bronchitis. However, the pharmacological mechanism of mangiferin in the treatment of bronchitis remains to be elucidated. Macrophage classical activation is important role in the process of bronchial airway inflammation, and interferon regulatory factor 5 (IRF5) has been identified as a key regulatory factor for macrophage classical activation. The present study used the THP‑1 human monocyte cell line to investigate whether mangiferin inhibits macrophage classical activation via suppressing IRF5 expression in vitro. THP‑1 cells were differentiated to macrophages by phorbol 12‑myristate 13‑acetate. Macrophages were polarized to M1 macrophages following stimulation with lipopolysaccharide (LPS)/interferon‑γ (IFN‑γ). Flow cytometric analysis was conducted to detect the M1 macrophages. Reverse transcription‑quantitative polymerase chain reaction was used to investigate cellular IRF5 gene expression. Levels of proinflammatory cytokines and IRF5 were assessed following cell culture and cellular homogenization using enzyme‑linked immunosorbent assay. IRF5 protein and nuclei co‑localization was performed in macrophages with laser scanning confocal microscope immunofluorescence analysis. The results of the present study demonstrated that mangiferin significantly inhibits LPS/IFN‑γ stimulation‑induced classical activation of macrophages in vitro and markedly decreases proinflammatory cytokine release. In addition, cellular IRF5 expression was markedly downregulated. These results suggest that the inhibitory effect of mangiferin on classical activation of macrophages may be exerted via downregulation of cellular IRF5 expression levels.

  9. Mangiferin inhibits macrophage classical activation via downregulating interferon regulatory factor 5 expression

    Science.gov (United States)

    Wei, Zhiquan; Yan, Li; Chen, Yixin; Bao, Chuanhong; Deng, Jing; Deng, Jiagang

    2016-01-01

    Mangiferin is a natural polyphenol and the predominant effective component of Mangifera indica Linn. leaves. For hundreds of years, Mangifera indica Linn. leaf has been used as an ingredient in numerous traditional Chinese medicine preparations for the treatment of bronchitis. However, the pharmacological mechanism of mangiferin in the treatment of bronchitis remains to be elucidated. Macrophage classical activation is important role in the process of bronchial airway inflammation, and interferon regulatory factor 5 (IRF5) has been identified as a key regulatory factor for macrophage classical activation. The present study used the THP-1 human monocyte cell line to investigate whether mangiferin inhibits macrophage classical activation via suppressing IRF5 expression in vitro. THP-1 cells were differentiated to macrophages by phorbol 12-myristate 13-acetate. Macrophages were polarized to M1 macrophages following stimulation with lipopolysaccharide (LPS)/interferon-γ (IFN-γ). Flow cytometric analysis was conducted to detect the M1 macrophages. Reverse transcription-quantitative polymerase chain reaction was used to investigate cellular IRF5 gene expression. Levels of proinflammatory cytokines and IRF5 were assessed following cell culture and cellular homogenization using enzyme-linked immunosorbent assay. IRF5 protein and nuclei co-localization was performed in macrophages with laser scanning confocal microscope immunofluorescence analysis. The results of the present study demonstrated that mangiferin significantly inhibits LPS/IFN-γ stimulation-induced classical activation of macrophages in vitro and markedly decreases proinflammatory cytokine release. In addition, cellular IRF5 expression was markedly downregulated. These results suggest that the inhibitory effect of mangiferin on classical activation of macrophages may be exerted via downregulation of cellular IRF5 expression levels. PMID:27277156

  10. Split-Cre complementation restores combination activity on transgene excision in hair roots of transgenic tobacco.

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    Mengling Wen

    Full Text Available The Cre/loxP system is increasingly exploited for genetic manipulation of DNA in vitro and in vivo. It was previously reported that inactive ''split-Cre'' fragments could restore Cre activity in transgenic mice when overlapping co-expression was controlled by two different promoters. In this study, we analyzed recombination activities of split-Cre proteins, and found that no recombinase activity was detected in the in vitro recombination reaction in which only the N-terminal domain (NCre of split-Cre protein was expressed, whereas recombination activity was obtained when the C-terminal (CCre or both NCre and CCre fragments were supplied. We have also determined the recombination efficiency of split-Cre proteins which were co-expressed in hair roots of transgenic tobacco. No Cre recombination event was observed in hair roots of transgenic tobacco when the NCre or CCre genes were expressed alone. In contrast, an efficient recombination event was found in transgenic hairy roots co-expressing both inactive split-Cre genes. Moreover, the restored recombination efficiency of split-Cre proteins fused with the nuclear localization sequence (NLS was higher than that of intact Cre in transgenic lines. Thus, DNA recombination mediated by split-Cre proteins provides an alternative method for spatial and temporal regulation of gene expression in transgenic plants.

  11. Complement activation at the motor end-plates in amyotrophic lateral sclerosis

    NARCIS (Netherlands)

    El Idrissi, N.B.; Bosch, S.; Ramaglia, V.; Aronica, E.; Baas, F.; Troost, D

    2016-01-01

    BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a fatal progressive neurodegenerative disease with no available therapy. Components of the innate immune system are activated in the spinal cord and central nervous system of ALS patients. Studies in the SOD1(G93A) mouse show deposition of C1q and C

  12. Complement activation at the motor end-plates in amyotrophic lateral sclerosis

    NARCIS (Netherlands)

    El Idrissi, N.B.; Bosch, S.; Ramaglia, V.; Aronica, E.; Baas, F.; Troost, D

    2016-01-01

    BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a fatal progressive neurodegenerative disease with no available therapy. Components of the innate immune system are activated in the spinal cord and central nervous system of ALS patients. Studies in the SOD1(G93A) mouse show deposition of C1q and

  13. Inhibition of Myeloperoxidase Activity in Cystic Fibrosis Sputum by Peptide Inhibitor of Complement C1 (PIC1)

    Science.gov (United States)

    Hair, Pamela S.; Sass, Laura A.; Krishna, Neel K.

    2017-01-01

    Myeloperoxidase is the major peroxidase enzyme in neutrophil granules and implicated in contributing to inflammatory lung damage in cystic fibrosis. Free myeloperoxidase is present in cystic fibrosis lung fluid and generates hypochlorous acid. Here we report a new inhibitor of myeloperoxidase activity, Peptide Inhibitor of Complement C1 (PIC1). Using TMB as the oxidizing substrate, PIC1 inhibited myeloperoxidase activity in cystic fibrosis sputum soluble fractions by an average of a 3.4-fold decrease (P = 0.02). PIC1 also dose-dependently inhibited myeloperoxidase activity in a neutrophil lysate or purified myeloperoxidase by up to 28-fold (P < 0.001). PIC1 inhibited myeloperoxidase activity similarly, on a molar basis, as the specific myeloperoxidase inhibitor 4-Aminobenzoic acid hydrazide (ABAH) for various oxidizing substrates. PIC1 was able to protect the heme ring of myeloperoxidase from destruction by NaOCl, assayed by spectral analysis. PIC1 incubated with oxidized TMB reversed the oxidation state of TMB, as measured by absorbance at 450 nm, with a 20-fold reduction in oxidized TMB (P = 0.02). This result was consistent with an antioxidant mechanism for PIC1. In summary, PIC1 inhibits the peroxidase activity of myeloperoxidase in CF sputum likely via an antioxidant mechanism. PMID:28135312

  14. Hypoxia and classical activation limits Mycobacterium tuberculosis survival by Akt-dependent glycolytic shift in macrophages

    OpenAIRE

    Matta, S K; Kumar, D.

    2016-01-01

    Cellular reactive oxygen species (ROS) is a major antibacterial defense mechanism used by macrophages upon activation. Exposure of Mycobacterium tuberculosis (Mtb)-infected macrophages to hypoxia is known to compromise the survival of the pathogen. Here we report that the hypoxia-induced control of intracellular Mtb load in RAW 264.7 macrophages was mediated by regulating the cellular ROS levels. We show that similar to classical activation, hypoxia incubation of macrophages resulted in decre...

  15. Classical macrophage activation up-regulates several matrix metalloproteinases through mitogen activated protein kinases and nuclear factor-κB.

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    Wei-Chun Huang

    Full Text Available Remodelling of the extracellular matrix (ECM and cell surface by matrix metalloproteinases (MMPs is an important function of monocytes and macrophages. Recent work has emphasised the diverse roles of classically and alternatively activated macrophages but the consequent regulation of MMPs and their inhibitors has not been studied comprehensively. Classical activation of macrophages derived in vitro from un-fractionated CD16(+/- or negatively-selected CD16(- macrophages up-regulated MMP-1, -3, -7, -10, -12, -14 and -25 and decreased TIMP-3 steady-state mRNA levels. Bacterial lipopolysaccharide, IL-1 and TNFα were more effective than interferonγ except for the effects on MMP-25, and TIMP-3. By contrast, alternative activation decreased MMP-2, -8 and -19 but increased MMP -11, -12, -25 and TIMP-3 steady-state mRNA levels. Up-regulation of MMPs during classical activation depended on mitogen activated protein kinases, phosphoinositide-3-kinase and inhibitor of κB kinase-2. Effects of interferonγ depended on janus kinase-2. Where investigated, similar effects were seen on protein concentrations and collagenase activity. Moreover, activity of MMP-1 and -10 co-localised with markers of classical activation in human atherosclerotic plaques in vivo. In conclusion, classical macrophage activation selectively up-regulates several MMPs in vitro and in vivo and down-regulates TIMP-3, whereas alternative activation up-regulates a distinct group of MMPs and TIMP-3. The signalling pathways defined here suggest targets for selective modulation of MMP activity.

  16. Blast-induced moderate neurotrauma (BINT) elicits early complement activation and tumor necrosis factor α (TNFα) release in a rat brain.

    Science.gov (United States)

    Dalle Lucca, Jurandir J; Chavko, Mikulas; Dubick, Michael A; Adeeb, Saleena; Falabella, Michael J; Slack, Jessica L; McCarron, Richard; Li, Yansong

    2012-07-15

    Blast-induced neurotrauma (BINT) is a major medical concern yet its etiology is largely undefined. Complement activation may play a role in the development of secondary injury following traumatic brain injury; however, its role in BINT is still undefined. The present study was designed to characterize the complement system and adaptive immune-inflammatory responses in a rat model of moderate BINT. Anesthetized rats were exposed to a moderate blast (120 kPa) using an air-driven shock tube. Brain tissue injury, systemic and local complement, cerebral edema, inflammatory cell infiltration, and pro-inflammatory cytokine production were measured at 0.5, 3, 48, 72, 120, and 168 h. Injury to brain tissue was evaluated by histological evaluation. Systemic complement was measured via ELSIA. The remaining measurements were determined by immunohistoflourescent staining. Moderate blast triggers moderate brain injuries, elevated levels of local brain C3/C5b-9 and systemic C5b-9, increased leukocyte infiltration, unregulated tumor necrosis factor alpha (TNFα), and aquaporin-4 in rat brain cortex at 3- and 48-hour post blast. Early immune-inflammatory response to BINT involves complement and TNFα, which correlates with hippocampus and cerebral cortex damage. Complement and TNFα activation may be a novel therapeutic target for reducing the damaging effects of BINT inflammation.

  17. Activation of serum complement in Posner-Schlossman syndrome patients%青光眼睫状体炎综合征患者血液中补体系统活化状态的分析

    Institute of Scientific and Technical Information of China (English)

    陈文杰; 赵军; 祝天辉; 彭诗茗; 黄晓生

    2016-01-01

    Background Activation of serum complement system is involved in the pathological process of uveitis and open angle glaucoma.Pathogenesis and pathological characteristics of Posner-Schlossman syndrome (PSS) are similar to uveitis and open angle glaucoma.However,etiology of PSS remains unelucidated.The activation complement in PSS patients' serum is rarely reported.Objective The aim of this study was to investigate the activation of serum complement in PSS patients for PSS pathogenesis.Methods A prospective case-controlled study was designed.The peripheral blood simples of 79 PSS patients were collected from Shenzhen Eye Hospital during December 2013 to December 2015,and the peripheral blood simples were obtained from 83 unrelated healthy blood donors as healthy control group.Immuno-scatter turbidmetry was adopted to detect the common activated components in complement pathway in each group including complement C3 (a vital intersection molecule in the three pathways),C4 (the vital molecule both the complement classical and lectin pathways),split products C3a,soluble membrane attack complex (sC5b-9),C 1q (complement classical pathway),L-ficolin (complement lectin pathway),complement factor Bb (complement alternative pathway),IgG,IgA and IgM.The correlation between serum C3a content and sC5b-9 content in PSS group was analyzed.The serum contents of fabric binding protein 2 (FCN2) (a marker of serum classical pathway),factor Bb (a marker of complement alternative pathway),C3a (the common activation products of three complement activation pathways),and sC5b-9 were assayed by ELISA.This research protocal was approved by Shenzhen Eye Hospital and written informed consent was obtained from each PSS patient prior to any medical examination.Results Compared with normal control group,the serum levels of C3,C4,C3a,sC5b-9,C1q,FCN2,IgG,IgA and IgM were significantly higher in PSS group (Z =-4.743,-2.913,-1.985,-2.620,-2.062,-2.500,-7.010,-6.327,-3.652,all at P < 0.05).The serum

  18. The TLR4-active morphine metabolite morphine-3-glucuronide does not elicit macrophage classical activation in vitro

    Directory of Open Access Journals (Sweden)

    Samira Khabbazi

    2016-11-01

    Full Text Available Macrophages are abundant in the tumor microenvironment where they adopt a pro-tumor phenotype following alternative polarization induced by paracrine factors from cancer and stromal cells. In contrast, classically activated macrophages have tumoricidal activities, such that the polarization of tumor-associated macrophages has become a novel therapeutic target. Toll-like receptor 4 engagement promotes classical activation of macrophages, and recent literature suggests TLR4 agonism to prevent metastasis and promote survival in experimental metastasis models. A growing number of studies indicate that TLR4 can respond to opioids, including the opioid receptor-inactive morphine metabolite morphine-3-glucuronide (M3G. We measured the activation of TLR4 in a reporter cell line exogenously expressing TLR4 and TLR4 co-receptors, and confirmed that M3G weakly but significantly activates TLR4. We hypothesized that M3G would promote the expression of classical activation signature genes in macrophages in vitro. We exposed mouse and human macrophage cell lines to M3G or the TLR4 activator lipopolysaccharide (LPS, alone or in combination with interferon gamma (IFN-γ. The classical macrophage activation markers tested were iNOS, CD86, IL-6 or TNF-α in RAW 264.7 cells and IL-6, IL-12, IL-23, TNF-α, CXCL10 and CXCL11 in THP1 cells. Our results show that despite exhibiting TLR4-activation ability, M3G does not elicit the expression of classical activation markers in LPS-responsive macrophages.

  19. Considerations for the Characterization and Interpretation of Results Related to Alternative Complement Activation in Monkeys Associated with Oligonucleotide-Based Therapeutics.

    Science.gov (United States)

    Henry, Scott P; Seguin, Rosanne; Cavagnaro, Joy; Berman, Cindy; Tepper, Jeff; Kornbrust, Douglas

    2016-08-01

    This article provides an overview of the discussions held by the Immunomodulatory Subcommittee of the Oligonucleotide Safety Working Group on complement activation induced by oligonucleotides, most notably the phosphorothioate-containing oligonucleotides. Alternative complement pathway activation in monkeys is a common effect of single-stranded phosphorothioate backbone oligonucleotides in toxicology studies. This article discusses the mechanism for activation, general investigational strategy, and the impact of various chemical modifications. The goal is to provide the best practice approach to characterizing this effect, understanding the implication of the species specificity, and the interpretation of clinical relevance.

  20. The lectin pathway of complement activation is a critical component of the innate immune response to pneumococcal infection

    DEFF Research Database (Denmark)

    Ali, Youssif M; Lynch, Nicholas J; Haleem, Kashif S;

    2012-01-01

    to pneumococcal infection and fail to opsonize Streptococcus pneumoniae in the none-immune host. This defect in complement opsonisation severely compromises pathogen clearance in the lectin pathway deficient host. Using sera from mice and humans with defined complement deficiencies, we demonstrate that mouse...

  1. Redefining the transcriptional regulatory dynamics of classically and alternatively activated macrophages by deepCAGE transcriptomics

    KAUST Repository

    Roy, S.

    2015-06-27

    Classically or alternatively activated macrophages (M1 and M2, respectively) play distinct and important roles for microbiocidal activity, regulation of inflammation and tissue homeostasis. Despite this, their transcriptional regulatory dynamics are poorly understood. Using promoter-level expression profiling by non-biased deepCAGE we have studied the transcriptional dynamics of classically and alternatively activated macrophages. Transcription factor (TF) binding motif activity analysis revealed four motifs, NFKB1_REL_RELA, IRF1,2, IRF7 and TBP that are commonly activated but have distinct activity dynamics in M1 and M2 activation. We observe matching changes in the expression profiles of the corresponding TFs and show that only a restricted set of TFs change expression. There is an overall drastic and transient up-regulation in M1 and a weaker and more sustainable up-regulation in M2. Novel TFs, such as Thap6, Maff, (M1) and Hivep1, Nfil3, Prdm1, (M2) among others, were suggested to be involved in the activation processes. Additionally, 52 (M1) and 67 (M2) novel differentially expressed genes and, for the first time, several differentially expressed long non-coding RNA (lncRNA) transcriptome markers were identified. In conclusion, the finding of novel motifs, TFs and protein-coding and lncRNA genes is an important step forward to fully understand the transcriptional machinery of macrophage activation.

  2. Aurin tricarboxylic acid self-protects by inhibiting aberrant complement activation at the C3 convertase and C9 binding stages.

    Science.gov (United States)

    Lee, Moonhee; Guo, Jian-Ping; McGeer, Edith G; McGeer, Patrick L

    2013-05-01

    Aberrant complement activation is known to exacerbate the pathology in a spectrum of degenerative diseases of aging. We previously reported that aurin tricarboxylic acid (ATA) is an orally effective agent which prevents formation of the membrane attack complex of complement. It inhibits C9 attachment to tissue bound C5b678 and thus prevents bystander lysis of host cells. In this study, we investigated the effects of ATA on the alternative complement pathway. We found that ATA prevented cleavage of the tissue bound properdin-C3b-Factor B complex into the active C3 convertase enzyme properdin-C3b-Factor Bb. This inhibition was reversed by adding Factor D to the serum. Using enzyme-linked immunosorbent type assays, we established that ATA binds directly to Factor D and C9 but not to properdin or other complement proteins. We conclude that ATA, by inhibiting at two stages of the alternative pathway, might be a particularly effective therapeutic agent in conditions such as macular degeneration, paroxysmal nocturnal hemoglobinemia, and rheumatoid arthritis, in which activation of the alternative complement pathway initiates self damage.

  3. Mangiferin inhibits macrophage classical activation via downregulating interferon regulatory factor 5 expression

    OpenAIRE

    Wei, Zhiquan; YAN Li; Chen, Yixin; Bao, Chuanhong; Deng, Jing; Deng, Jiagang

    2016-01-01

    Mangiferin is a natural polyphenol and the predominant effective component of Mangifera indica Linn. leaves. For hundreds of years, Mangifera indica Linn. leaf has been used as an ingredient in numerous traditional Chinese medicine preparations for the treatment of bronchitis. However, the pharmacological mechanism of mangiferin in the treatment of bronchitis remains to be elucidated. Macrophage classical activation is important role in the process of bronchial airway inflammation, and interf...

  4. Complement evasion by Staphylococcus aureus

    NARCIS (Netherlands)

    Jongerius, I.

    2010-01-01

    The complement system is the first line of defense against invading microorganisms. Activation of the complement system results in the coverage of bacteria with C3b, resulting in phagocytosis, and formation of C5a which is important for chemotaxis of neutrophils towards the site of infection. Staphy

  5. Topical application of PPADS inhibits complement activation and choroidal neovascularization in a model of age-related macular degeneration.

    Directory of Open Access Journals (Sweden)

    Kerstin Birke

    Full Text Available Age-related macular degeneration (AMD is the most common cause of blindness among the elderly. AMD patients have elevated levels of membrane attack complex (MAC in their choroidal blood vessels and retinal pigment epithelium (RPE. MAC forms pores in cell membranes. Low levels of MAC result in an elevation of cytokine release such as vascular endothelial growth factor (VEGF that promotes the formation of choroidal neovascularization (CNV. High levels of MAC result in cell lysis and RPE degeneration is a hallmark of advanced AMD. The current standard of care for CNV associated with wet AMD is intravitreal injection of anti-VEGF molecules every 4 to 12 weeks. Such injections have significant side effects. Recently, it has been found that membrane pore-forming proteins such as α-haemolysin can mediate their toxic effects through auto- and paracrine signaling and that complement-induced lysis is amplified through ATP release followed by P2X receptor activation. We hypothesized that attenuation of P2X receptor activation may lead to a reduction in MAC deposition and consequent formation of CNV. Hence, in this study we investigated topical application of the purinergic P2X antagonist Pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS as a potential treatment for AMD. We found that 4.17 µM PPADS inhibited formation of HUVEC master junctions and master segments by 74.7%. In a human complement mediated cell lysis assay, 104 µM PPADS enabled almost complete protection of Hepa1c1c7 cells from 1% normal human serum mediated cell lysis. Daily topical application of 4.17 mM PPADS for 3 days attenuated the progression of laser induced CNV in mice by 41.8% and attenuated the deposition of MAC at the site of the laser injury by 19.7%. Our data have implications for the future treatment of AMD and potentially other ocular disorders involving CNV such as angioid streaks, choroidal rupture and high myopia.

  6. Interaction between human complement and a pectin type polysaccharide fraction, PMII, from the leaves of Plantago major L.

    Science.gov (United States)

    Michaelsen, T E; Gilje, A; Samuelsen, A B; Høgåsen, K; Paulsen, B S

    2000-11-01

    The interaction between a pectin type polysaccharide fraction, PMII, isolated from the leaves of Plantago major, and human complement was tested in two different hemolytic complement-fixation tests and in addition by two ELISA methods detecting complement-activation products. Sera were used as a complement source of 10 arbitrary human volunteers, individually and as a pool. The complement-fixation tests were designed to measure the concentration of the pectin necessary to inhibit 50% of the hemolysis (ICH(50)). The ELISA tests for complement-activation products were measured in AU/mg using a fully activated serum as a standard. We observed a more than 200-fold difference in ICH(50) activity of the PMII pectin in one of the hemolytic tests by varying the individual sera used as complement-source. On the other hand, the ELISA complement-activation tests showed no significant variation in activity of the PMII depending on the complement-serum used. The level of antibodies against PMII detected in the complement-sera did not correlate with the ICH(50) activity of PMII. The results show that PMII is a potent complement activator with an activity of the same order of magnitude on a weight basis as that of aggregated human immunoglobulin (Ig)G. This activation leads to a complement consumption probably explaining the PMII's effect in the complement-fixation tests. PMII seems to be an activator both on the classical and the alternative pathway of activation. The results might be related to the reported wound-healing effect of the leaves of Plantago major.

  7. Herbal complement inhibitors in the treatment of neuroinflammation: future strategy for neuroprotection.

    Science.gov (United States)

    Kulkarni, Amod P; Kellaway, Laurie A; Kotwal, Girish J

    2005-11-01

    The upregulated complement system plays a damaging role in disorders of the central nervous system (CNS). The classical and alternate pathways are two major pathways activated in neuroinflammatory disorders such as Alzheimer's disease, multiple sclerosis, traumatic brain injury, spinal cord injury, HIV-associated dementia, Parkinson's disease, and mad cow disease. Failure of currently available anti-inflammatory agents, especially cyclooxygenase inhibitors, in offering significant neuroprotection in large epidemiologic clinical trials of CNS disorders suggests an urgent need for the development of new neuroprotective agents. The positive preclinical outcomes in treating CNS disorders by complement regulatory molecules, such as vaccinia virus complement control protein, suggest the possibility of using complement-inhibitory molecules as neuroprotective agents. Several active ingredients of herbal origin are found to have complement-inhibitory activity. These herbal ingredients along with other anti-inflammatory roles might be useful in treating neuroinflammation associated with CNS disorders. Active ingredients of herbal origin with complement inhibitory ingredients are summarized and classified according to their chemical nature and specificity towards the major pathways activating the complement system. The structure activity relationship of some specific examples is also discussed in this report. This information might be helpful in formulating a natural panacea against complement-mediated neuroinflammation.

  8. Regulator of Complement Activation (RCA) Locus in Chicken: Identification of Chicken RCA Gene Cluster and Functional RCA Proteins

    National Research Council Canada - National Science Library

    Oshiumi, Hiroyuki; Shida, Kyoko; Goitsuka, Ryo; Kimura, Yuko; Katoh, Jun; Ohba, Shinya; Tamaki, Yuichiroh; Hattori, Takashi; Yamada, Nozomi; Inoue, Norimitsu; Matsumoto, Misako; Mizuno, Shigeki; Seya, Tsukasa

    2005-01-01

    ...; and Department of Microbiology and Immunology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan A 150-kb DNA fragment, which contains the gene of the chicken complement regulatory protein CREM...

  9. Circadian and diurnal variation of circulating immune complexes, complement-mediated solubilization, and the complement split product C3d in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Petersen, Ivan; Baatrup, Gunnar; Brandslund, I;

    1986-01-01

    Nine patients with active classical rheumatoid arthritis (ARA criteria) were studied with reference to circadian variation of immunological and clinical parameters. Complement-mediated solubilization (CMS) of immune complexes (IC) and the level of circulating IC were found to be inversely related...

  10. Cardiac Sirt1 mediates the cardioprotective effect of caloric restriction by suppressing local complement system activation after ischemia-reperfusion.

    Science.gov (United States)

    Yamamoto, Tsunehisa; Tamaki, Kayoko; Shirakawa, Kohsuke; Ito, Kentaro; Yan, Xiaoxiang; Katsumata, Yoshinori; Anzai, Atsushi; Matsuhashi, Tomohiro; Endo, Jin; Inaba, Takaaki; Tsubota, Kazuo; Sano, Motoaki; Fukuda, Keiichi; Shinmura, Ken

    2016-04-15

    Caloric restriction (CR) confers cardioprotection against ischemia-reperfusion (I/R) injury. We previously found the essential roles of endothelial nitric oxide synthase in the development of CR-induced cardioprotection and Sirt1 activation during CR (Shinmura K, Tamaki K, Ito K, Yan X, Yamamoto T, Katsumata Y, Matsuhashi T, Sano M, Fukuda K, Suematsu M, Ishii I. Indispensable role of endothelial nitric oxide synthase in caloric restriction-induced cardioprotection against ischemia-reperfusion injury.Am J Physiol Heart Circ Physiol 308: H894-H903, 2015). However, the exact mechanism by which Sirt1 in cardiomyocytes mediates the cardioprotective effect of CR remains undetermined. We subjected cardiomyocyte-specific Sirt1 knockout (CM-Sirt1(-/-)) mice and the corresponding control mice to either 3-mo ad libitum feeding or CR (-40%). Isolated perfused hearts were subjected to 25-min global ischemia, followed by 60-min reperfusion. The recovery of left ventricle function after I/R was improved, and total lactate dehydrogenase release into the perfusate during reperfusion was attenuated in the control mice treated with CR, but a similar cardioprotective effect of CR was not observed in the CM-Sirt1(-/-)mice. The expression levels of cardiac complement component 3 (C3) at baseline and the accumulation of C3 and its fragments in the ischemia-reperfused myocardium were attenuated by CR in the control mice, but not in the CM-Sirt1(-/-)mice. Resveratrol treatment also attenuated the expression levels of C3 protein in cultured neonatal rat ventricular cardiomyocytes. Moreover, the degree of myocardial I/R injury in conventional C3 knockout (C3(-/-)) mice treated with CR was similar to that in the ad libitum-fed C3(-/-)mice, although the expression levels of Sirt1 were enhanced by CR. These results demonstrate that cardiac Sirt1 plays an essential role in CR-induced cardioprotection against I/R injury by suppressing cardiac C3 expression. This is the first report suggesting

  11. Genetic regulation of microglia activation, complement expression, and neurodegeneration in a rat model of traumatic brain injury.

    Science.gov (United States)

    Bellander, Bo-Michael; Lidman, Olle; Ohlsson, Marcus; Meijer, Britt; Piehl, Fredrik; Svensson, Mikael

    2010-08-01

    Secondary brain damage following traumatic brain injury in part depends on neuroinflammation, a process where genetic factors may play an important role. We examined the response to a standardized cortical contusion in two different inbred rat strains, Dark Agouti (DA) and Piebald Virol Glaxo (PVG). Both are well characterized in models of autoimmune neuroinflammation, where DA is susceptible and PVG resistant. We found that infiltration of polymorphonuclear granulocytes (PMN) at 3-day postinjury was more pronounced in PVG. DA was more infiltrated by T cells at 3-day postinjury, showed an enhanced glial activation at 7-day postinjury and higher expression of C3 complement at 7-day postinjury. Neurodegeneration, assessed by Fluoro-Jade, was also more pronounced in the DA strain at 30-day postinjury. These results demonstrate differences in the response to cortical contusion injury attributable to genetic influences and suggest a link between injury-induced inflammation and neurodegeneration. Genetic factors that regulate inflammation elicited by brain trauma may be important for the development of secondary brain damage.

  12. Complement Component 3 Regulates IFN-α Production by Plasmacytoid Dendritic Cells following TLR7 Activation by a Plant Virus-like Nanoparticle.

    Science.gov (United States)

    Lebel, Marie-Ève; Langlois, Marie-Pierre; Daudelin, Jean-François; Tarrab, Esther; Savard, Pierre; Leclerc, Denis; Lamarre, Alain

    2017-01-01

    The increasing use of plant viruses for the development of new vaccines and immunotherapy approaches poses questions regarding the mechanism by which the mammalian immune system recognizes these viruses. For example, although natural Abs (NA) and complement are key components of the innate immune system involved in the opsonization, phagocytosis, and destruction of microorganisms infecting mammals, their implication in plant virus recognition and immunogenicity is not well defined. In this study, we address the involvement of NA and the complement system in the activation of innate immunity through engagement of TLR7 with papaya mosaic virus (PapMV)-like nanoparticles. We demonstrate that NA, although binding to PapMV, are not involved in its recognition by the immune system. On the other hand, C3 strongly binds to PapMV nanoparticles and its depletion significantly reduces PapMV's interaction with immune cells. Unexpectedly, however, we observed increased immune cell activation following administration of PapMV to complement-depleted mice. TLR7 activation by PapMV in the absence of C3 induced higher IFN-α production, resulting in superior immune cell activation and increased immunotherapeutic properties. In conclusion, in this study we established the involvement of the complement system in the recognition and the phagocytosis of PapMV nanoparticles and identified an unsuspected role for C3 in regulating the production of IFN-α following TLR7 activation.

  13. Complement inhibiting properties of dragon's blood from Croton draco.

    Science.gov (United States)

    Tsacheva, Ivanka; Rostan, Joerg; Iossifova, Tania; Vogler, Bernhard; Odjakova, Mariela; Navas, Hernan; Kostova, Ivanka; Kojouharova, Michaela; Kraus, Wolfgang

    2004-01-01

    The latex of Croton draco, its extracts and several latex components have been investigated for their influence on both classical (CP) and alternative (AP) activation pathways of the complement system using a hemolytic assay. The best inhibition was found for the classical pathway. The latex, ethyl acetate and ethyl ether extracts exhibited extremely high inhibition on the CP (94, 90 and 77%, respectively) at a concentration of 1 mg/ml. The flavonoid myricitrin, the alkaloid taspine and the cyclopeptides P1 and P2 showed high inhibition on CP (83, 91, 78 and 63%, respectively) at a concentration of 0.9 mM.

  14. Function of Serum Complement in Drinking Water Arsenic Toxicity

    Directory of Open Access Journals (Sweden)

    Laila N. Islam

    2012-01-01

    Full Text Available Serum complement function was evaluated in 125 affected subjects suffering from drinking water arsenic toxicity. Their mean duration of exposure was 7.4±5.3 yrs, and the levels of arsenic in drinking water and urine samples were 216±211 and 223±302 μg/L, respectively. The mean bactericidal activity of complement from the arsenic patients was 92% and that in the unexposed controls was 99% (P<0.01, but heat-inactivated serum showed slightly elevated activity than in controls. In patients, the mean complement C3 was 1.56 g/L, and C4 was 0.29 g/L compared to 1.68 g/L and 0.25 g/L, respectively, in the controls. The mean IgG in the arsenic patients was 24.3 g/L that was highly significantly elevated (P<0.001. Arsenic patients showed a significant direct correlation between C3 and bactericidal activity (P=0.014. Elevated levels of C4 indicated underutilization and possibly impaired activity of the classical complement pathway. We conclude reduced function of serum complement in drinking water arsenic toxicity.

  15. Blast-Induced Moderate Neurotrauma (BINT) Elicits Early Complement Activation and Tumor Necrosis Factor Alpha (TNFalpha) Release in a Rat Brain

    Science.gov (United States)

    2012-04-25

    for the damaged tissue. Mol Psychiatry 1997;2:133–6. [20] Chavko M, Prusaczyk WK, McCarron RM. Lung injury and recovery after exposure to blast...complement pathways after contusion -induced spinal cord injury. J Neurotrauma2004;21:1831–46. [23] Bellander BM, von Holst H, Fredman P, Svensson M...Activation of the complement cascade and increase of clusterin in the brain following a cortical contusion in the adult rat. J Neurosurg 1996;85:468–75. [24

  16. Inhibition of the alternative complement activation pathway in traumatic brain injury by a monoclonal anti-factor B antibody: a randomized placebo-controlled study in mice

    Directory of Open Access Journals (Sweden)

    Holers V Michael

    2007-05-01

    Full Text Available Abstract Background The posttraumatic response to traumatic brain injury (TBI is characterized, in part, by activation of the innate immune response, including the complement system. We have recently shown that mice devoid of a functional alternative pathway of complement activation (factor B-/- mice are protected from complement-mediated neuroinflammation and neuropathology after TBI. In the present study, we extrapolated this knowledge from studies in genetically engineered mice to a pharmacological approach using a monoclonal anti-factor B antibody. This neutralizing antibody represents a specific and potent inhibitor of the alternative complement pathway in mice. Methods A focal trauma was applied to the left hemisphere of C57BL/6 mice (n = 89 using a standardized electric weight-drop model. Animals were randomly assigned to two treatment groups: (1 Systemic injection of 1 mg monoclonal anti-factor B antibody (mAb 1379 in 400 μl phosphate-buffered saline (PBS at 1 hour and 24 hours after trauma; (2 Systemic injection of vehicle only (400 μl PBS, as placebo control, at identical time-points after trauma. Sham-operated and untreated mice served as additional negative controls. Evaluation of neurological scores and analysis of brain tissue specimens and serum samples was performed at defined time-points for up to 1 week. Complement activation in serum was assessed by zymosan assay and by murine C5a ELISA. Brain samples were analyzed by immunohistochemistry, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL histochemistry, and real-time RT-PCR. Results The mAb 1379 leads to a significant inhibition of alternative pathway complement activity and to significantly attenuated C5a levels in serum, as compared to head-injured placebo-treated control mice. TBI induced histomorphological signs of neuroinflammation and neuronal apoptosis in the injured brain hemisphere of placebo-treated control mice for up to 7 days. In contrast, the

  17. Activation of Human Complement System by Dextran-Coated Iron Oxide Nanoparticles Is Not Affected by Dextran/Fe Ratio, Hydroxyl Modifications, and Crosslinking

    DEFF Research Database (Denmark)

    Wang, Guankui; Chen, Fangfang; Banda, Nirmal K

    2016-01-01

    , whereas opsonization with C3 fragments promotes rapid recognition and clearance of nanomaterials by mononuclear phagocytes. We used dextran-coated superparamagnetic iron oxide nanoparticles (SPIO), which are potent activators of the complement system, to study the role of nanoparticle surface chemistry...

  18. Features of complement activation-related pseudoallergy to liposomes with different surface charge and PEGylation : comparison of the porcine and rat responses

    NARCIS (Netherlands)

    Dézsi, László; Fülöp, Tamás; Mészáros, Tamás; Szénási, Gábor; Urbanics, Rudolf; Vázsonyi, Csenge; Őrfi, Erik; Rosivall, László; Nemes, Réka; Kok, Robbert Jan; Metselaar, Josbert M; Storm, G; Szebeni, János

    2014-01-01

    Pigs are known to provide a sensitive model for studying complement (C) activation-related pseudoallergy (CARPA), a hypersensitivity reaction to liposomal and many other nanomedicines that limits their clinical use. The utility of rats as a CARPA model has, however, not been analyzed to date in deta

  19. Features of complement activation-related pseudoallergy to liposomes with different surface charge and PEGylation: Comparison of the porcine and rat responses

    NARCIS (Netherlands)

    Dézsi, L.; Fülöp, T.; Mészàros, T.; Szénåsi, G.; Urbanics, R.; Våzsonyi, C.; Orfi, E.; Rosivall, L.; Nemes, R.; Kok, R.J.; Metselaar, J.M.; Storm, G.; Szebeni, J.

    2014-01-01

    Pigs are known to provide a sensitive model for studying complement (C) activation-related pseudoallergy (CARPA), a hypersensitivity reaction to liposomal and many other nanomedicines that limits their clinical use. The utility of rats as a CARPA model has, however, not been analyzed to date in deta

  20. Fosb gene products contribute to excitotoxic microglial activation by regulating the expression of complement C5a receptors in microglia.

    Science.gov (United States)

    Nomaru, Hiroko; Sakumi, Kunihiko; Katogi, Atsuhisa; Ohnishi, Yoshinori N; Kajitani, Kosuke; Tsuchimoto, Daisuke; Nestler, Eric J; Nakabeppu, Yusaku

    2014-08-01

    The Fosb gene encodes subunits of the activator protein-1 transcription factor complex. Two mature mRNAs, Fosb and ΔFosb, encoding full-length FOSB and ΔFOSB proteins respectively, are formed by alternative splicing of Fosb mRNA. Fosb products are expressed in several brain regions. Moreover, Fosb-null mice exhibit depressive-like behaviors and adult-onset spontaneous epilepsy, demonstrating important roles in neurological and psychiatric disorders. Study of Fosb products has focused almost exclusively on neurons; their function in glial cells remains to be explored. In this study, we found that microglia express equivalent levels of Fosb and ΔFosb mRNAs to hippocampal neurons and, using microarray analysis, we identified six microglial genes whose expression is dependent on Fosb products. Of these genes, we focused on C5ar1 and C5ar2, which encode receptors for complement C5a. In isolated Fosb-null microglia, chemotactic responsiveness toward the truncated form of C5a was significantly lower than that in wild-type cells. Fosb-null mice were significantly resistant to kainate-induced seizures compared with wild-type mice. C5ar1 mRNA levels and C5aR1 immunoreactivity were increased in wild-type hippocampus 24 hours after kainate administration; however, such induction was significantly reduced in Fosb-null hippocampus. Furthermore, microglial activation after kainate administration was significantly diminished in Fosb-null hippocampus, as shown by significant reductions in CD68 immunoreactivity, morphological change and reduced levels of Il6 and Tnf mRNAs, although no change in the number of Iba-1-positive cells was observed. These findings demonstrate that, under excitotoxicity, Fosb products contribute to a neuroinflammatory response in the hippocampus through regulation of microglial C5ar1 and C5ar2 expression.

  1. The complement system and adverse pregnancy outcomes.

    Science.gov (United States)

    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.

  2. Systemic lupus erythematosus and primary fibromyalgia can be distinguished by testing for cell-bound complement activation products

    Science.gov (United States)

    Wallace, Daniel J; Silverman, Stuart L; Conklin, John; Barken, Derren; Dervieux, Thierry

    2016-01-01

    Objective We sought to establish the performance of cell-bound complement activation products (CB-CAPs) as a diagnostic tool to distinguish primary fibromyalgia (FM) from systemic lupus erythematosus (SLE). Methods A total of 75 SLE and 75 primary FM adult subjects who fulfilled appropriate classification criteria were enrolled prospectively. CB-CAPs (erythrocyte-C4d (EC4d) and B-lymphocyte-C4d (BC4d)) were determined by flow cytometry. Antinuclear antibodies (ANAs) were determined using indirect immunofluorescence while other autoantibodies were determined by solid-phase assays. The CB-CAPs in a multi-analyte assay with algorithm (MAAA) relied on two consecutive tiers of analysis that was reported as an overall positive or negative assessment. Test performance was assessed using sensitivity, specificity, positive and negative likelihood ratio (LR). Results ANAs yielded 80% positives for SLE and 33% positives for FM. High CB-CAP expression (EC4d >14 units or BC4d >60 units) was 43% sensitive and 96% specific for SLE. The CB-CAPs in MAAA assessment was evaluable in 138 of the 150 subjects enrolled (92%) and yielded 60% sensitivity (CI 95% 48% to 72%) for SLE with no FM patient testing positive (100% specificity). A positive test result was associated with a strong positive LR for SLE (>24, CI 95%; 6 to 102), while a negative test result was associated with a moderate negative LR (0.40; CI 95% 0.30 to 0.54). Conclusion Our data indicate that CB-CAPs in MAAA can distinguish FM from SLE. PMID:26870391

  3. Complement in health and disease.

    Science.gov (United States)

    Carroll, Maria V; Sim, Robert B

    2011-09-16

    The complement system consists of about 35-40 proteins and glycoproteins present in blood plasma or on cell surfaces. Its main biological function is to recognise "foreign" particles and macromolecules, and to promote their elimination either by opsonisation or lysis. Although historically complement has been studied as a system for immune defence against bacteria, it has an important homeostatic role in which it recognises damaged or altered "self" components. Thus complement has major roles in both immune defence against microorganisms, and in clearance of damaged or "used" host components. Since complement proteins opsonise or lyse cells, complement can damage healthy host cells and tissues. The system is regulated by many endogenous regulatory proteins. Regulation is sometimes imperfect and both too much and too little complement activation is associated with many diseases. Excessive or inappropriate activation can cause tissue damage in diseases such as rheumatoid arthritis, age-related macular degeneration (AMD), multiple sclerosis, ischemia-reperfusion injury (e.g. ischemic stroke). Insufficient complement activity is associated with susceptibility to infection (mainly bacterial) and development of autoimmune disease, like SLE (systemic lupus erythematosus).

  4. Focal hyperemia followed by spreading oligemia and impaired activation of rCBF in classic migraine

    DEFF Research Database (Denmark)

    Olesen, J; Larsen, B; Lauritzen, M

    1981-01-01

    Regional cerebral blood flow (rCBF) was measured in 254 areas of a hemisphere with the xenon 133 intraarterial injection method. Six cases of classic migraine were followed from the normal state into the prodromal phase, and in 3 cases further into the headache phase. One patient with common...... anteriorly in the course of 15 to 45 minutes. In 4 patients a global oligemia was observed. In 4 patients severe headache was present concomitantly with oligemia and with no sign of hyperemia or nonhomogeneous brain perfusion. The normal rCBF increase during cortical activity (hand movement, speech...

  5. Properdin deficiency protects from 5-fluorouracil-induced small intestinal mucositis in a complement activation-independent, interleukin-10-dependent mechanism.

    Science.gov (United States)

    Jain, U; Midgen, C A; Woodruff, T M; Schwaeble, W J; Stover, C M; Stadnyk, A W

    2017-04-01

    Intestinal mucositis is a serious complication of chemotherapy that leads to significant morbidity that may require dose or drug adjustments. Specific mitigating strategies for mucositis are unavailable, due partly to an incomplete understanding of the pathogenic mechanisms. We have previously shown an effect of properdin, a positive regulator of complement activation, in models of colitis. Here we use properdin-deficient (P(KO) ) mice to interrogate the role of properdin and complement in small intestinal mucositis. Mucositis was induced by five daily injections of 5-fluorouracil (5-FU) in wild-type (WT), P(KO) , interleukin (IL)-10(-/-) and properdin/IL-10(-/-) double knock-out (DKO) mice. At the time of euthanasia their jejunum was collected for histology, immunohistochemistry and cytokine and complement activation measurements. Complement became activated in mice receiving 5-FU, indicated by increased intestinal levels of C3a and C5a. Compared to WT, P(KO) mice experienced significantly less mucositis, despite C3a levels as high as inflamed WT mice and slightly less C5a. Conversely, P(KO) mice had higher intestinal levels of IL-10. IL-10 expression was mainly by epithelial cells in both uninflamed and inflamed P(KO) mice. IL-10(-/-) mice proved to be highly susceptible to mucositis and DKO mice were equally susceptible, demonstrating that a lack of properdin does not protect mice lacking IL-10. We interpret our findings to indicate that, to a significant extent, the inflammation of mucositis is properdin-dependent but complement activation-independent. Additionally, the benefit achieved in the absence of properdin is associated with increased IL-10 levels, and IL-10 is important in limiting mucositis. © 2017 British Society for Immunology.

  6. Complement regulates conventional DC-mediated NK-cell activation by inducing TGF-β1 in Gr-1+ myeloid cells.

    Science.gov (United States)

    Qing, Xiaoping; Koo, Gloria C; Salmon, Jane E

    2012-07-01

    Complement activation modulates DC-mediated T-cell activation, but whether complement affects DC-mediated priming of NK cells is unknown. Here, we demonstrated that conventional DCs (cDCs) from C3(-/-) and C5aR(-/-) mice are hyperresponsive to polyI:C, a TLR3 ligand, leading to enhanced NK-cell activation. We found that cDCs lack C5a receptor (C5aR) and do not respond to C5a directly. Depletion of Gr-1(+) myeloid cells augments polyI:C-induced cDC activation in WT but not in C3(-/-) or C5aR(-/-) mice, indicating that the effect of complement activation on cDCs is indirectly mediated through C5aR-expressing Gr-1(+) myeloid cells. We further demonstrated that the mechanism by which Gr-1(+) myeloid cells regulate the activity of cDCs involves C5a-dependent TGF-β1 production in Gr-1(+) myeloid cells. C5a enhances and blocking C5aR decreases TGF-β1 production in cultured bone marrow Gr-1(+) CD11b(+) cells. C5aR deficiency is associated with reduced circulating TGF-β1 levels, while depleting Gr-1(+) myeloid cells abrogates this difference between WT and C5aR(-/-) mice. Lastly, we showed that enhanced cDC-NK-cell activity in C3(-/-) mice led to delayed melanoma tumor growth. Thus, complement activation indirectly regulates cDC-NK-cell activation in response to inflammatory stimuli such as TLR3 by promoting TGF-β1 production in Gr-1(+) myeloid cells at steady state.

  7. Calculation of Classical Polar-Activity Indices Using Their Modern Variants

    Science.gov (United States)

    Barkhatov, N. A.; Korolev, A. V.; Levitin, A. E.; Sakharov, S. Yu.

    2004-03-01

    At present, the auroral-electrojet AE, AU, and AL indices are calculated using a smaller number of stations than earlier. This influences the accuracy of estimates of the magnetospheric activity components, which are performed using the relationships with modern indices AE8 (obtained from the data of 8 stations) substituted instead of the classical indices AE12 (obtained from the data of 12 stations). In this paper, we develop an artificial neural-network (ANN) algoritm for recalculating the classical polar-activity indices from modern ones. It is demonstrated that the developed ANN is capable of retrieving the AE12-index from data of 8 stations (AE8) with efficiency reaching 90% in some cases. The results obtained allow one to estimate the error in the representation of the auroral-electrojet activity by modern AE8 indices as compared with the ones introduced into geophysical research by their creators. We also develop a retrieval technique for polar indices, which employs data on solar-wind parameters.

  8. A novel "complement-metabolism-inflammasome axis" as a key regulator of immune cell effector function.

    Science.gov (United States)

    Arbore, Giuseppina; Kemper, Claudia

    2016-07-01

    The inflammasomes are intracellular multiprotein complexes that induce and regulate the generation of the key pro-inflammatory cytokines IL-1β and IL-18 in response to infectious microbes and cellular stress. The activation of inflammasomes involves several upstream signals including classic pattern or danger recognition systems such as the TLRs. Recently, however, the activation of complement receptors, such as the anaphylatoxin C3a and C5a receptors and the complement regulator CD46, in conjunction with the sensing of cell metabolic changes, for instance increased amino acid influx and glycolysis (via mTORC1), have emerged as additional critical activators of the inflammasome. This review summarizes recent advances in our knowledge about complement-mediated inflammasome activation, with a specific focus on a novel "complement - metabolism - NLRP3 inflammasome axis."

  9. Complement-dependent proinflammatory properties of the Alzheimer's disease beta-peptide.

    Science.gov (United States)

    Bradt, B M; Kolb, W P; Cooper, N R

    1998-08-03

    Large numbers of neuritic plaques (NP), largely composed of a fibrillar insoluble form of the beta-amyloid peptide (Abeta), are found in the hippocampus and neocortex of Alzheimer's disease (AD) patients in association with damaged neuronal processes, increased numbers of activated astrocytes and microglia, and several proteins including the components of the proinflammatory complement system. These studies address the hypothesis that the activated complement system mediates the cellular changes that surround fibrillar Abeta deposits in NP. We report that Abeta peptides directly and independently activate the alternative complement pathway as well as the classical complement pathway; trigger the formation of covalent, ester-linked complexes of Abeta with activation products of the third complement component (C3); generate the cytokine-like C5a complement-activation fragment; and mediate formation of the proinflammatory C5b-9 membrane attack complex, in functionally active form able to insert into and permeabilize the membrane of neuronal precursor cells. These findings provide inflammation-based mechanisms to account for the presence of complement components in NP in association with damaged neurons and increased numbers of activated glial cells, and they have potential implications for the therapy of AD.

  10. Classic Galactosemia: Study on the Late Prenatal Development of GALT Specific Activity in a Sheep Model.

    Science.gov (United States)

    Coelho, Ana I; Bierau, Jörgen; Lindhout, Martijn; Achten, Jelle; Kramer, Boris W; Rubio-Gozalbo, M Estela

    2017-09-01

    Classic galactosemia results from deficient activity of galactose-1-phosphate uridylyltransferase (GALT), a key enzyme of galactose metabolism. Despite early diagnosis and early postnatal therapeutic intervention, patients still develop neurologic and fertility impairments. Prenatal developmental toxicity has been hypothesized as a determinant factor of disease. In order to shed light on the importance of prenatal GALT activity, several studies have examined GALT activity throughout development. GALT was shown to increase with gestational age in 7-28 weeks human fetuses; later stages were not investigated. Prenatal studies in animals focused exclusively on brain and hepatic GALT activity. In this study, we aim to examine GALT specific activity in late prenatal and adult stages, using a sheep model. Galactosemia acute target-organs-liver, small intestine and kidney-had the highest late prenatal activity, whereas the chronic target-organs-brain and ovary-did not exhibit a noticeable pre- or postnatal different activity compared with nontarget organs. This is the first study on GALT specific activity in the late prenatal stage for a wide variety of organs. Our findings suggest that GALT activity cannot be the sole pathogenic factor accounting for galactosemia long-term complications, and that some organs/cells might have a greater susceptibility to galactose toxicity. Anat Rec, 300:1570-1575, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  11. Role of complement in glomerular diseases.

    Science.gov (United States)

    Mao, Song; Zhang, Jianhua

    2016-01-01

    The complement system, composed of nearly 30 proteins, is a key regulator of immunity. The complement system is critical for protecting hosts from invading pathogens. Dysregulation of this system is associated with susceptibility to infection and various autoimmune diseases. Furthermore, complement activation due to the defective regulation of the alternative pathway will induce glomerular diseases. Anti-complement therapy has been applied in various glomerular diseases. Signaling pathways might be very important in the pathogenesis of glomerular diseases. This review will give a relatively complete signaling pathway flowchart for complement and a comprehensive understanding of the underlying role of complement in glomerular diseases.

  12. Human pentraxin 3 binds to the complement regulator c4b-binding protein.

    Directory of Open Access Journals (Sweden)

    Anne Braunschweig

    Full Text Available The long pentraxin 3 (PTX3 is a soluble recognition molecule with multiple functions including innate immune defense against certain microbes and the clearance of apoptotic cells. PTX3 interacts with recognition molecules of the classical and lectin complement pathways and thus initiates complement activation. In addition, binding of PTX3 to the alternative complement pathway regulator factor H was shown. Here, we show that PTX3 binds to the classical and lectin pathway regulator C4b-binding protein (C4BP. A PTX3-binding site was identified within short consensus repeats 1-3 of the C4BP α-chain. PTX3 did not interfere with the cofactor activity of C4BP in the fluid phase and C4BP maintained its complement regulatory activity when bound to PTX3 on surfaces. While C4BP and factor H did not compete for PTX3 binding, the interaction of C4BP with PTX3 was inhibited by C1q and by L-ficolin. PTX3 bound to human fibroblast- and endothelial cell-derived extracellular matrices and recruited functionally active C4BP to these surfaces. Whereas PTX3 enhanced the activation of the classical/lectin pathway and caused enhanced C3 deposition on extracellular matrix, deposition of terminal pathway components and the generation of the inflammatory mediator C5a were not increased. Furthermore, PTX3 enhanced the binding of C4BP to late apoptotic cells, which resulted in an increased rate of inactivation of cell surface bound C4b and a reduction in the deposition of C5b-9. Thus, in addition to complement activators, PTX3 interacts with complement inhibitors including C4BP. This balanced interaction on extracellular matrix and on apoptotic cells may prevent excessive local complement activation that would otherwise lead to inflammation and host tissue damage.

  13. Level of complement activity predicts cardiac dysfunction after acute myocardial infarction treated with primary percutaneous coronary intervention

    DEFF Research Database (Denmark)

    Haahr-Pedersen, Sune; Bjerre, Mette; Flyvbjerg, Allan

    2009-01-01

    The positive effect of reperfusion after ST-elevation myocardial infarction (STEMI) can be reduced by ischemic/reperfusion (I/R) injury.Mannose-binding-lectin (MBL) and soluble C5b-9 (membrane-attack-complex) are involved in complement-driven cell lysis and may play a role in human myocardial I...

  14. Circulating microparticles remain associated with complement activation despite intensive anti-inflammatory therapy in early rheumatoid arthritis

    NARCIS (Netherlands)

    van Eijk, I.C.; Tushuizen, M.E.; Sturk, A.; Dijkmans, B.A.C.; Boers, M.; Voskuyl, A.E.; Diamant, M.; Wolbink, G.J.; Nieuwland, R.; Nurmohamed, M.T.

    2010-01-01

    Objectives Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease characterised by synovitis and joint destruction. The pathogenesis of RA is not clear, but is considered to be an immune-mediated inflammatory disorder, in which the complement system plays an important role. Although ce

  15. Classic Maya civilization collapse associated with reduction in tropical cyclone activity

    Science.gov (United States)

    Medina, M. A.; Polanco-Martinez, J. M.; Lases-Hernández, F.; Bradley, R. S.; Burns, S. J.

    2013-12-01

    In light of the increased destructiveness of tropical cyclones observed over recent decades one might assume that an increase and not a decrease in tropical cyclone activity would lead to societal stress and perhaps collapse of ancient cultures. In this study we present evidence that a reduction in the frequency and intensity of tropical Atlantic cyclones could have contributed to the collapse of the Maya civilization during the Terminal Classic Period (TCP, AD. 800-950). Statistical comparisons of a quantitative precipitation record from the Yucatan Peninsula (YP) Maya lowlands, based on the stalagmite known as Chaac (after the Mayan God of rain and agriculture), relative to environmental proxy records of El Niño/Southern Oscillation (ENSO), tropical Atlantic sea surface temperatures (SSTs), and tropical Atlantic cyclone counts, suggest that these records share significant coherent variability during the TCP and that summer rainfall reductions between 30 and 50% in the Maya lowlands occurred in association with decreased Atlantic tropical cyclones. Analysis of modern instrumental hydrological data suggests cyclone rainfall contributions to the YP equivalent to the range of rainfall deficits associated with decreased tropical cyclone activity during the collapse of the Maya civilization. Cyclone driven precipitation variability during the TCP, implies that climate change may have triggered Maya civilization collapse via freshwater scarcity for domestic use without significant detriment to agriculture. Pyramid in Tikal, the most prominent Maya Kingdom that collapsed during the Terminal Classic Period (circa C.E. 800-950) Rainfall feeding stalagmites inside Rio Secreto cave system, Yucatan, Mexico.

  16. Focal hyperemia followed by spreading oligemia and impaired activation of rCBF in classic migraine

    Energy Technology Data Exchange (ETDEWEB)

    Olesen, J.; Larsen, B.; Lauritzen, M.

    1981-04-01

    Regional cerebral blood flow (rCBF) was measured in 254 areas of a hemisphere with the xenon 133 intraarterial injection method. Six cases of classic migraine were followed from the normal state into the prodromal phase, and in 3 cases further into the headache phase. One patient with common migraine was similarly followed during his only classic attack. The attacks were initiated by focal hyperemia in 3 patients. During prodromes all patients displayed occipitoparietal rCBF reduction (oligemia), but in only 1 case did the reduction approach critical values. Oligemia gradually spread anteriorly in the course of 15 to 45 minutes. In 4 patients a global oligemia was observed. In 4 patients severe headache was present concomitantly with oligemia and with no sign of hyperemia or nonhomogeneous brain perfusion. The normal rCBF increase during cortical activity (hand movement, speech, and similar activities) was impaired in 6 patients. The results indicate that the vasospastic model of the migraine attack is too simplistic.

  17. Human IgG1 monoclonal antibody against human collagen 17 noncollagenous 16A domain induces blisters via complement activation in experimental bullous pemphigoid model.

    Science.gov (United States)

    Li, Qiang; Ujiie, Hideyuki; Shibaki, Akihiko; Wang, Gang; Moriuchi, Reine; Qiao, Hong-jiang; Morioka, Hiroshi; Shinkuma, Satoru; Natsuga, Ken; Long, Heather A; Nishie, Wataru; Shimizu, Hiroshi

    2010-12-15

    Bullous pemphigoid (BP) is an autoimmune blistering disease caused by IgG autoantibodies targeting the noncollagenous 16A (NC16A) domain of human collagen 17 (hCOL17), which triggers blister formation via complement activation. Previous in vitro analysis demonstrated that IgG1 autoantibodies showed much stronger pathogenic activity than IgG4 autoantibodies; however, the exact pathogenic role of IgG1 autoantibodies has not been fully demonstrated in vivo. We constructed a recombinant IgG1 mAb against hCOL17 NC16A from BP patients. In COL17-humanized mice, this mAb effectively reproduced a BP phenotype that included subepidermal blisters, deposition of IgG1, C1q and C3, neutrophil infiltration, and mast cell degranulation. Subsequently, alanine substitutions at various C1q binding sites were separately introduced to the Fc region of the IgG1 mAb. Among these mutated mAbs, the one that was mutated at the P331 residue completely failed to activate the complement in vitro and drastically lost pathogenic activity in COL17-humanized mice. These findings indicate that P331 is a key residue required for complement activation and that IgG1-dependent complement activation is essential for blister formation in BP. This study is, to our knowledge, the first direct evidence that IgG1 Abs to hCOL17 NC16A can induce blister formation in vivo, and it raises the possibility that IgG1 mAbs with Fc modification may be used to block pathogenic epitopes in autoimmune diseases.

  18. Factor H and factor H-related protein 1 bind to human neutrophils via complement receptor 3, mediate attachment to Candida albicans, and enhance neutrophil antimicrobial activity.

    Science.gov (United States)

    Losse, Josephine; Zipfel, Peter F; Józsi, Mihály

    2010-01-15

    The host complement system plays an important role in protection against infections. Several human-pathogenic microbes were shown to acquire host complement regulators, such as factor H (CFH), that downregulate complement activation at the microbial surface and protect the pathogens from the opsonic and lytic effects of complement. Because CFH can also bind to host cells, we addressed the role of CFH and CFH-related proteins as adhesion ligands in host-pathogen interactions. We show that the CFH family proteins CFH, CFH-like protein 1 (CFHL1), CFH-related protein (CFHR) 1, and CFHR4 long isoform bind to human neutrophil granulocytes and to the opportunistic human-pathogenic yeast Candida albicans. Two major binding sites, one within the N-terminus and one in the C-terminus of CFH, were found to mediate binding to neutrophils. Complement receptor 3 (CD11b/CD18; alpha(M)beta2 integrin) was identified as the major cellular receptor on neutrophils for CFH, CFHL1, and CFHR1, but not for CFHR4 long isoform. CFH and CFHR1 supported cell migration. Furthermore, CFH, CFHL1, and CFHR1 increased attachment of neutrophils to C. albicans. Adhesion of neutrophils to plasma-opsonized yeasts was reduced when CFH binding was inhibited by specific Abs or when using CFH-depleted plasma. Yeast-bound CFH and CFHR1 enhanced the generation of reactive oxygen species and the release of the antimicrobial protein lactoferrin by human neutrophils, and resulted in a more efficient killing of the pathogen. Thus, CFH and CFHR1, when bound on the surface of C. albicans, enhance antimicrobial activity of human neutrophils.

  19. Ataxia-telangiectasia group D complementing gene (ATDC promotes lung cancer cell proliferation by activating NF-κB pathway.

    Directory of Open Access Journals (Sweden)

    Zhong-Ping Tang

    Full Text Available Previous studies suggested Ataxia-telangiectasia group D complementing gene (ATDC as an oncogene in many types of cancer. However, its expression and biological functions in non-small cell lung cancer (NSCLC remain unclear. Herein, we investigated its expression pattern in 109 cases of human NSCLC samples by immunohistochemistry and found that ATDC was overexpressed in 62 of 109 NSCLC samples (56.88%. ATDC overexpression correlated with histological type (p<0.0001, tumor status (p = 0.0227 and histological differentiation (p = 0.0002. Next, we overexpressed ATDC in normal human bronchial epithelial cell line HBE and depleted its expression in NSCLC cell lines A549 and H1299. MTT and colony formation assay showed that ATDC overexpression promoted cell proliferation while its depletion inhibited cell growth. Furthermore, cell cycle analysis showed that ATDC overexpression decreased the percentage of cells in G1 phase and increased the percentage of cells in S phase, while ATDC siRNA treatment increased the G1 phase percentage and decreased the S phase percentage. Further study revealed that ATDC overexpression could up-regulate cyclin D1 and c-Myc expression in HBE cells while its depletion down-regulated cyclin D1 and c-Myc expression in A549 and H1299 cells. In addition, ATDC overexpression was also associated with an increased proliferation index, cyclin D1 and c-Myc expression in human NSCLC samples. Further experiments demonstrated that ATDC up-regulated cyclin D1 and c-Myc expression independent of wnt/β-catenin or p53 signaling pathway. Interestingly, ATDC overexpression increased NF-κB reporter luciferase activity and p-IκB protein level. Correspondingly, NF-κB inhibitor blocked the effect of ATDC on up-regulation of cyclin D1 and c-Myc. In conclusion, we demonstrated that ATDC could promote lung cancer proliferation through NF-κB induced up-regulation of cyclin D1 and c-Myc.

  20. The Activity of Surface Electromyographic Signal of Selected Muscles during Classic Rehabilitation Exercise

    Directory of Open Access Journals (Sweden)

    Jinzhuang Xiao

    2016-01-01

    Full Text Available Objectives. Prone bridge, unilateral bridge, supine bridge, and bird-dog are classic rehabilitation exercises, which have been advocated as effective ways to improve core stability among healthy individuals and patients with low back pain. The aim of this study was to investigate the activity of seven selected muscles during rehabilitation exercises through the signal of surface electromyographic. Approaches. We measured the surface electromyographic signals of four lower limb muscles, two abdominal muscles, and one back muscle during rehabilitation exercises of 30 healthy students and then analyzed its activity level using the median frequency method. Results. Different levels of muscle activity during the four rehabilitation exercises were observed. The prone bridge and unilateral bridge caused the greatest muscle fatigue; however, the supine bridge generated the lowest muscle activity. There was no significant difference (P>0.05 between left and right body side muscles in the median frequency slope during the four rehabilitation exercises of seven muscles. Conclusions. The prone bridge can affect the low back and lower limb muscles of most people. The unilateral bridge was found to stimulate muscles much more active than the supine bridge. The bird-dog does not cause much fatigue to muscles but can make most selected muscles active.

  1. ACL Report. A Report of the Activities of the American Classical League 1977-1978.

    Science.gov (United States)

    Lawall, Gilbert

    Five topics of interest to persons involved in classical studies are discussed in this report: (1) "A Survey of the Classical Scene" focusses on the future of classical studies in elementary and secondary schools with some mention of the situation in colleges and universities. (2) "ACL: The State of the League" includes officers, agenda and…

  2. ACL Report. A Report of the Activities of the American Classical League 1977-1978.

    Science.gov (United States)

    Lawall, Gilbert

    Five topics of interest to persons involved in classical studies are discussed in this report: (1) "A Survey of the Classical Scene" focusses on the future of classical studies in elementary and secondary schools with some mention of the situation in colleges and universities. (2) "ACL: The State of the League" includes…

  3. Level of complement activity predicts cardiac dysfunction after acute myocardial infarction treated with primary percutaneous coronary intervention

    DEFF Research Database (Denmark)

    2009-01-01

    BACKGROUND: The positive effect of reperfusion after ST-elevation myocardial infarction (STEMI) can be reduced by ischemic/reperfusion (I/R) injury.Mannose-binding-lectin (MBL) and soluble C5b-9 (membrane-attack-complex) are involved in complement-driven cell lysis and may play a role in human...... descending coronary artery who were successfully treated with pPCI. Cardiac dysfunction was defined as left ventricular ejection fraction LVEF or = 35%. After adjustment...

  4. Complement system in zebrafish.

    Science.gov (United States)

    Zhang, Shicui; Cui, Pengfei

    2014-09-01

    Zebrafish is recently emerging as a model species for the study of immunology and human diseases. Complement system is the humoral backbone of the innate immune defense, and our knowledge as such in zebrafish has dramatically increased in the recent years. This review summarizes the current research progress of zebrafish complement system. The global searching for complement components in genome database, together with published data, has unveiled the existence of all the orthologues of mammalian complement components identified thus far, including the complement regulatory proteins and complement receptors, in zebrafish. Interestingly, zebrafish complement components also display some distinctive features, such as prominent levels of extrahepatic expression and isotypic diversity of the complement components. Future studies should focus on the following issues that would be of special importance for understanding the physiological role of complement components in zebrafish: conclusive identification of complement genes, especially those with isotypic diversity; analysis and elucidation of function and mechanism of complement components; modulation of innate and adaptive immune response by complement system; and unconventional roles of complement-triggered pathways.

  5. Complement in the Homeostatic and Ischemic Brain

    Science.gov (United States)

    Alawieh, Ali; Elvington, Andrew; Tomlinson, Stephen

    2015-01-01

    The complement system is a component of the immune system involved in both recognition and response to pathogens, and it is implicated in an increasing number of homeostatic and disease processes. It is well documented that reperfusion of ischemic tissue results in complement activation and an inflammatory response that causes post-reperfusion injury. This occurs following cerebral ischemia and reperfusion and triggers secondary damage that extends beyond the initial infarcted area, an outcome that has rationalized the use of complement inhibitors as candidate therapeutics after stroke. In the central nervous system, however, recent studies have revealed that complement also has essential roles in synaptic pruning, neurogenesis, and neuronal migration. In the context of recovery after stroke, these apparent divergent functions of complement may account for findings that the protective effect of complement inhibition in the acute phase after stroke is not always maintained in the subacute and chronic phases. The development of effective stroke therapies based on modulation of the complement system will require a detailed understanding of complement-dependent processes in both early neurodegenerative events and delayed neuro-reparatory processes. Here, we review the role of complement in normal brain physiology, the events initiating complement activation after cerebral ischemia-reperfusion injury, and the contribution of complement to both injury and recovery. We also discuss how the design of future experiments may better characterize the dual role of complement in recovery after ischemic stroke. PMID:26322048

  6. Aktywnośc filozoficzna kobiet w Grecji okresu klasycznego (WOMEN'S PHILOSOPHICAL ACTIVITY IN CLASSICAL GREECE

    Directory of Open Access Journals (Sweden)

    Bartłomiej Ramian

    2005-12-01

    Full Text Available The authors discuss in this paper the matter of philosophical activity of women in classical Greece. Hardly ever can characters of women philosophers be found in textbooks concerning history of ancient philosophy. This is relevant to the social situation in Greece of that time, where women existed on the margins of public life. To show this, they refer to Aristotle's work, as much as to non-philosophical sources. In spite of the fact that women's activity was reduced to the private sphere, a number of woman philosophers appear in the history of Greek thought. Circumstances which enabled them to take up activity on this ground were varied. Some of the women were members of philosophical schools, in case of others it seems that a particular personal situation played a key role, as they were either daughters or wives of philosophers. Regardless of the reasons, taking up philosophical activity must have required great courage and determination. Without any doubt, women philosophers must have been uncommon characters and their development on this ground can be seen as overcoming the social role imposed on them.

  7. Lipid homeostasis and inflammatory activation are disturbed in classically activated macrophages with peroxisomal β-oxidation deficiency.

    Science.gov (United States)

    Geric, Ivana; Tyurina, Yulia Y; Krysko, Olga; Krysko, Dmitri V; De Schryver, Evelyn; Kagan, Valerian E; Van Veldhoven, Paul P; Baes, Myriam; Verheijden, Simon

    2017-09-22

    Macrophage activation is characterized by pronounced metabolic adaptation. Classically activated macrophages show decreased rates of mitochondrial fatty acid oxidation and oxidative phosphorylation and acquire a glycolytic state together with their pro-inflammatory phenotype. In contrast, alternatively activated macrophages require oxidative phosphorylation and mitochondrial fatty acid oxidation for their anti-inflammatory function. Although it is evident that mitochondrial metabolism is regulated during macrophage polarization and essential for macrophage function, little is known on the regulation and role of peroxisomal β-oxidation during macrophage activation. In this study, we show that peroxisomal β-oxidation is strongly decreased in classically activated bone marrow derived macrophages (BMDM) and mildly induced in alternatively activated BMDM. To examine the role of peroxisomal β-oxidation in macrophages, we used Mfp2(-/-) BMDM lacking the key enzyme of this pathway. Impairment of peroxisomal β-oxidation in Mfp2(-/-) BMDM did not cause lipid accumulation but rather an altered distribution of lipid species with very long chain fatty acids accumulating in the triglyceride and phospholipid fraction. These lipid alterations in Mfp2(-/-) macrophages led to decreased inflammatory activation of Mfp2(-/-) BMDM and peritoneal macrophages evidenced by impaired production of several inflammatory cytokines and chemokines, but did not affect anti-inflammatory polarization. The disturbed inflammatory responses of Mfp2(-/-) macrophages did not affect immune cell infiltration, as mice with selective elimination of MFP2 from myeloid cells showed normal monocyte and neutrophil influx upon challenge with zymosan. Together, these data demonstrate that peroxisomal β-oxidation is involved in fine-tuning the phenotype of macrophages, likely by influencing the dynamic lipid profile during macrophage polarization. This article is protected by copyright. All rights reserved

  8. An integrated assessment of morphology, size, and complement activation of the PEGylated liposomal doxorubicin products Doxil®, Caelyx®, DOXOrubicin, and SinaDoxosome

    DEFF Research Database (Denmark)

    Wibroe, Peter P; Ahmadvand, Davoud; Oghabian, Mohammad Ali

    2016-01-01

    In order to improve patient's benefit and safety, comprehensive regulatory guidelines on specificities of Non-Biological Complex Drugs (NBCDs), such as doxorubicin-encapsulated liposomes, and their follow-on versions are needed. Here, we compare Doxil® and its European analog Caelyx® with the two...... follow-on products DOXOrubicin (approved by the US Food and Drug Administration) and SinaDoxosome (produced in Iran) by cryogenic transmission electron microscopy, dynamic light scattering and Nanoparticle Tracking Analysis, and assess their potential in activating the complement system in human sera. We...... to the presence of unilamellar vesicles with entrapped doxorubicin crystals, contained empty circular disks. Differences were also found in complement responses, which may be related to some morphological differences. This study has demonstrated an integrated biophysical and immunological toolbox for improved...

  9. Hereditary deficiency of the second component of complement (C2) in man: correlation of C2 haemolytic activity with immunochemical measurements of C2 protein

    Science.gov (United States)

    Ruddy, S.; Klemperer, M. R.; Rosen, F. S.; Austen, K. F.; Kumate, J.

    1970-01-01

    Measurements of the nine components of complement in the serums of 16 members of a kindred have established the diagnosis of hereditary deficiency of the second component of complement (C2). The autosomal recessive mode of inheritance resembles that of previously described families with C2 deficiency. Both C2 activity determinations with a stoichiometric haemolytic assay and C2 protein measurements with electroimmunodiffusion against antibody monospecific for C2 detect the heterozygous deficient state. Antigenic analysis, in vitro reconstitution experiments, and the constant ratio of C2 function to C2 protein indicate that the C2 synthesized by heterozygotes is indistinguishable from normal human C2. Studies of neonatal homozygous deficient serum and maternal heterozygous deficient serum show that transplacental passage of C2 does not occur. C2 deficiency in this family is not associated with clinical defects in host resistance. ImagesFIG. 3 PMID:4987909

  10. Complement activation by PEG-functionalized multi-walled carbon nanotubes is independent of PEG molecular mass and surface density

    DEFF Research Database (Denmark)

    Andersen, Alina Joukainen; Windschiegl, Barbara; Ilbasmis-Tamer, Sibel

    2013-01-01

    Carboxylated (4%) multi-walled carbon nanotubes were covalently functionalized with poly(ethylene glycol)1000 (PEG1000), PEG1500 and PEG4000 with a PEG loading of approximately 11% in all cases. PEG loading generated non-uniform and heterogeneous higher surface structures and increased nanotube...... eliminated. Our observations address the difficulty in making carbon nanotubes more compatible with innate immunity through covalent PEG functionalization as well as double PEGylation strategies. From the Clinical EditorComplement-mediated toxicity is a major limiting factor in certain nanomedicine...... applications. This study clarifies that PEGylation of carbon nanotubes is unlikely to address this complication....

  11. Complement the hemostatic system: an intimate relationship.

    Science.gov (United States)

    Weitz, Ilene Ceil

    2014-05-01

    The complement system is important part of our innate immune system and interacts directly with the hemostatic system. Disorders of complement activation or dysregulation resulting in excess complement generation, such as Paroxysmal Nocturnal Hemoglobinuria (PNH), atypical Hemolytic uremic Syndrome (aHUS) and antiphospholipid syndrome (APLS) have been associated with significant thrombophilia. Terminal Complement (C5b-9) deposition on endothelial and tumor cell membranes has also been reported in a variety of cancer. Recent developments in complement inhibition have given us new insights into the mechanism of thrombosis in these disorders.

  12. The Complement System: A Prey of Trypanosoma cruzi

    Directory of Open Access Journals (Sweden)

    Kárita C. F. Lidani

    2017-04-01

    Full Text Available Trypanosoma cruzi is a protozoan parasite known to cause Chagas disease (CD, a neglected sickness that affects around 6–8 million people worldwide. Originally, CD was mainly found in Latin America but more recently, it has been spread to countries in North America, Asia, and Europe due the international migration from endemic areas. Thus, at present CD represents an important concern of global public health. Most of individuals that are infected by T. cruzi may remain in asymptomatic form all lifelong, but up to 40% of them will develop cardiomyopathy, digestive mega syndromes, or both. The interaction between the T. cruzi infective forms and host-related immune factors represents a key point for a better understanding of the physiopathology of CD. In this context, the complement, as one of the first line of host defense against infection was shown to play an important role in recognizing T. cruzi metacyclic trypomastigotes and in controlling parasite invasion. The complement consists of at least 35 or more plasma proteins and cell surface receptors/regulators, which can be activated by three pathways: classical (CP, lectin (LP, and alternative (AP. The CP and LP are mainly initiated by immune complexes or pathogen-associated molecular patterns (PAMPs, respectively, whereas AP is spontaneously activated by hydrolysis of C3. Once activated, several relevant complement functions are generated which include opsonization and phagocytosis of particles or microorganisms and cell lysis. An important step during T. cruzi infection is when intracellular trypomastigotes are release to bloodstream where they may be target by complement. Nevertheless, the parasite uses a sequence of events in order to escape from complement-mediated lysis. In fact, several T. cruzi molecules are known to interfere in the initiation of all three pathways and in the assembly of C3 convertase, a key step in the activation of complement. Moreover, T. cruzi promotes secretion

  13. Human IgG is produced in a pro-form that requires clipping of C-terminal lysines for maximal complement activation

    DEFF Research Database (Denmark)

    van den Bremer, E. T. J.; Beurskens, F. J.; Voorhorst, M.

    2015-01-01

    Human IgG is produced with C-terminal lysines that are cleaved off in circulation. The function of this modification was unknown and generally thought not to affect antibody function. We recently reported that efficient C1q binding and complement-dependent cytotoxicity (CDC) requires IgG hexameri......Human IgG is produced with C-terminal lysines that are cleaved off in circulation. The function of this modification was unknown and generally thought not to affect antibody function. We recently reported that efficient C1q binding and complement-dependent cytotoxicity (CDC) requires Ig......G hexamerization at the cell surface. Here we demonstrate that C-terminal lysines may interfere with this process, leading to suboptimal C1q binding and CDC of cells opsonized with C-terminal lysine-containing IgG. After we removed these lysines with a carboxypeptidase, maximal complement activation was observed....... Interestingly, IgG1 mutants containing either a negative C-terminal charge or multiple positive charges lost CDC almost completely; however, CDC was fully restored by mixing C-terminal mutants of opposite charge. Our data indicate a novel post-translational control mechanism of human IgG: human IgG molecules...

  14. Anti-arthritic activity of a classical Ayurvedic formulation Vatari Guggulu in rats

    Directory of Open Access Journals (Sweden)

    Madhavi G. Patel

    2016-10-01

    Full Text Available In India, Vatari Guggulu has been traditionally used in the Ayurvedic system of medicine to treat rheumatoid arthritis (RA. The current study was undertaken to evaluate anti-arthritic activity of alcoholic extract of Vatari Guggulu in rats. Arthritis was induced by administration of formaldehyde (2%v/v or Complete Freund's Adjuvant (CFA into the sub-plantar surface of left hind paw of the animals. The extract was administered to the rats by oral gavages in different doses. Joint swelling was measured in formaldehyde induced arthritis. Various physical, biochemical and histopathological parameters were determined in CFA induced arthritis. Vatari Guggulu extract (VGE produced significant (P < 0.05 inhibition of joint swelling in both formaldehyde and CFA induced arthritis. The treatment also brought to normalcy the increased white blood cell (WBC count, rheumatoid factor (RF, erythrocyte sedimentation rate (ESR, cholesterol, triglycerides and LDL with an enhancement of haemoglobin (Hb levels and red blood cell (RBC count. These effects were found to be dose dependent. These effects were comparable with standard drug indomethacin. Histo-pathological studies of the ankles of VGE treated animals exhibited significant improvements. VGE did not show any toxic symptoms even at a dose of 2000 mg/kg in acute toxicity studies on rats. Thus, Vatari Guggulu, a classical Ayurvedic formulation of the Indian System of Medicine, exhibited significant anti-arthritic activity in formaldehyde and CFA induced arthritis in rats. This study corroborates the claims of Ayurveda on Vatari Guggulu.

  15. Discrimination between Host and Pathogens by the Complement System

    OpenAIRE

    Pangburn, Michael K.; Ferreira, Viviana P.; Cortes, Claudio

    2008-01-01

    Pathogen-specific complement activation requires direct recognition of pathogens and/or the absence of complement control mechanisms on their surfaces. Antibodies direct complement activation to potential pathogens recognized by the cellular innate and adaptive immune systems. Similarly, the plasma proteins MBL and ficolins direct activation to microorganisms expressing common carbohydrate structures. The absence of complement control proteins permits amplification of complement by the altern...

  16. Complement: an overview for the clinician.

    Science.gov (United States)

    Varela, Juan Carlos; Tomlinson, Stephen

    2015-06-01

    The complement system is an essential component of the immune system. It is a highly integrative system and has a number of functions, including host defense, removal of injured cells and debris, modulation of metabolic and regenerative processes, and regulation of adaptive immunity. Complement is activated via different pathways and it is regulated tightly by several mechanisms to prevent host injury. Imbalance between complement activation and regulation can manifest in disease and injury to self. This article provides an outline of complement activation pathways, regulatory mechanisms, and normal physiologic functions of the system.

  17. Role of Complement in Multiorgan Failure

    Directory of Open Access Journals (Sweden)

    Daniel Rittirsch

    2012-01-01

    Full Text Available 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.

  18. Complement activation capacity in plasma before and during high-dose prednisolone treatment and tapering in exacerbations of Crohn's disease and ulcerative colitis

    Directory of Open Access Journals (Sweden)

    Baatrup Gunnar

    2005-09-01

    Full Text Available Abstract Background Ulcerative colitis (UC and Crohn's disease (CD are characterized by intestinal inflammation mainly caused by a disturbance in the balance between cytokines and increased complement (C activation. Our aim was to evaluate possible associations between C activation capacity and prednisolone treatment. Methods Plasma from patients with exacerbations of UC (n = 18 or CD (n = 18 were collected before and during high dose prednisolone treatment (1 mg/kg body weight and tapering. Friedman's two way analysis of variance, Mann-Whitney U test and Wilcoxon signed-rank sum test were used Results Before treatment, plasma from CD patients showed significant elevations in all C-mediated analyses compared to the values obtained from 38 healthy controls (p Conclusion Our findings indicate that C activation capacity is up-regulated significantly in plasma from CD patients. The decreases observed after prednisolone treatment reflect a general down-regulation in immune activation.

  19. Membrane glucocorticoid receptor activation induces proteomic changes aligning with classical glucocorticoid effects.

    Science.gov (United States)

    Vernocchi, Sara; Battello, Nadia; Schmitz, Stephanie; Revets, Dominique; Billing, Anja M; Turner, Jonathan D; Muller, Claude P

    2013-07-01

    Glucocorticoids exert rapid nongenomic effects by several mechanisms including the activation of a membrane-bound glucocorticoid receptor (mGR). Here, we report the first proteomic study on the effects of mGR activation by BSA-conjugated cortisol (Cort-BSA). A subset of target proteins in the proteomic data set was validated by Western blot and we found them responding to mGR activation by BSA-conjugated cortisol in three additional cell lines, indicating a conserved effect in cells originating from different tissues. Changes in the proteome of BSA-conjugated cortisol treated CCRF-CEM leukemia cells were associated with early and rapid pro-apoptotic, immune-modulatory and metabolic effects aligning with and possibly "priming" classical activities of the cytosolic glucocorticoid receptor (cGR). PCR arrays investigating target genes of the major signaling pathways indicated that the mGR does not exert its effects through the transcriptional activity of any of the most common kinases in these leukemic cells, but RhoA signaling emerged from our pathway analysis. All cell lines tested displayed very low levels of mGR on their surface. Highly sensitive and specific in situ proximity ligation assay visualized low numbers of mGR even in cells previously thought to be mGR negative. We obtained similar results when using three distinct anti-GR monoclonal antibodies directed against the N-terminal half of the cGR. This strongly suggests that the mGR and the cGR have a high sequence homology and most probably originate from the same gene. Furthermore, the mGR appears to reside in caveolae and its association with caveolin-1 (Cav-1) was clearly detected in two of the four cell lines investigated using double recognition proximity ligation assay. Our results indicate however that Cav-1 is not necessary for membrane localization of the GR since CCRF-CEM and Jurkat cells have a functional mGR, but did not express this caveolar protein. However, if expressed, this membrane protein

  20. Systemic administration of Abeta mAb reduces retinal deposition of Abeta and activated complement C3 in age-related macular degeneration mouse model.

    Directory of Open Access Journals (Sweden)

    Ian Catchpole

    Full Text Available Age-related macular degeneration (AMD is a leading cause of legal blindness in the Western world. There are effective treatments for the vascular complications of neo-vascular AMD, but no effective therapies are available for the dry/atrophic form of the disease. A previously described transgenic CFH-gene deficient mouse model, (cfh-/-, shows hallmarks of early AMD. The ocular phenotype has been further analysed to demonstrate amyloid beta (Aβ rich basement membrane deposits associated with activated complement C3. Cfh-/- mice were treated systemically in both prophylactic and therapeutic regimes with an anti-Aβ monoclonal antibody (mAb, 6F6, to determine the effect on the cfh-/- retinal phenotype. Prophylactic treatment with 6F6 demonstrated a dose dependent reduction in the accumulation of both Aβ and activated C3 deposition. A similar reduction in the retinal endpoints could be seen after therapeutic treatment. Serum Aβ levels after systemic administration of 6F6 show accumulation of Aβ in the periphery suggestive of a peripheral sink mechanism. In summary, anti-Aβ mAb treatment can partially prevent or reverse ocular phenotypes of the cfh-/- mouse. The data support this therapeutic approach in humans potentially modulating two key elements in the pathogenesis of AMD - Aβ and activated, complement C3.

  1. The complement system in systemic autoimmune disease

    NARCIS (Netherlands)

    Chen, Min; Daha, Mohamed R.; Kallenberg, Cees G. M.

    2010-01-01

    Complement is part of the innate immune system. Its major function is recognition and elimination of pathogens via direct killing and/or stimulation of phagocytosis. Activation of the complement system is, however, also involved in the pathogenesis of the systemic autoimmune diseases. Activation via

  2. Expression of type 3 complement receptor on activated CD8+ T cells facilitates homing to inflammatory sites

    DEFF Research Database (Denmark)

    Nielsen, H V; Christensen, Jan Pravsgaard; Andersson, E C

    1994-01-01

    /macrophages and CD8+ cells, the majority of which are CD11b+. Adoptive transfer experiments involving i.v. transplantation of Ag-primed donor cells revealed that preincubation of the cells with 5C6 delayed the virus-specific delayed-type hypersensitivity reaction under conditions in which the recipient delivered......It has been reported that Ag-primed T cells may express the type 3 complement receptor (CR3; CD11b/CD18, Mac-1), but no clear function has been ascribed to this molecule on T cells. In our study, we have used a nondepleting mAb to CR3 (5C6) to study the relevance of CR3 expression for T-cell...... extravasation at inflammatory foci. The in vivo administration of 5C6 significantly reduced the severity of the T cell-mediated meningitis induced by intracerebral inoculation of lymphocytic choriomeningitis virus. FACS analysis of the inflammatory exudate showed that this consists of monocytes...

  3. Complement: Alive and Kicking Nanomedicines

    DEFF Research Database (Denmark)

    Andersen, Alina Joukainen; Hashemi, S.H.; Andresen, Thomas Lars;

    2009-01-01

    Administration of liposome- and polymer-based clinical nanomedicines, as well as many other proposed multifunctional nanoparticles, often triggers hypersensitivity reactions without the involvement of IgE. These anaphylactic reactions are believed to be secondary to activation of the complement s...

  4. Complement defects in patients with chronic rhinosinusitis

    DEFF Research Database (Denmark)

    Gaunsbaek, Maria Quisgaard; Lange, Bibi; Kjeldsen, Anette D;

    2012-01-01

    The complement system is an important part of our immune system, and complement defects lead generally to increased susceptibility to infections and autoimmune diseases. We have studied the role of complement activity in relation with chronic rhinosinusitis (CRS), and more specifically studied...... whether complement defects collectively predispose individuals for CRS or affect CRS severity. The participants comprised 87 CRS patients randomly selected from the general population, and a control group of 150 healthy blood donors. The CRS patients were diagnosed according to the European Position Paper...... on Rhinosinusitis and nasal Polyps criteria, and severity was evaluated by the Sino-nasal Outcome Test-22. Serum samples were analysed by ELISA for activity of the respective pathways of complement, and subsequently for serum levels of relevant components. We found that the frequency of complement defects...

  5. Alternative complement pathway deregulation is correlated with dengue severity.

    Directory of Open Access Journals (Sweden)

    Eduardo J M Nascimento

    Full Text Available BACKGROUND: The complement system, a key component that links the innate and adaptive immune responses, has three pathways: the classical, lectin, and alternative pathways. In the present study, we have analyzed the levels of various complement components in blood samples from dengue fever (DF and dengue hemorrhagic fever (DHF patients and found that the level of complement activation is associated with disease severity. METHODS AND RESULTS: Patients with DHF had lower levels of complement factor 3 (C3; p = 0.002 and increased levels of C3a, C4a and C5a (p<0.0001 when compared to those with the less severe form, DF. There were no significant differences between DF and DHF patients in the levels of C1q, immunocomplexes (CIC-CIq and CRP. However, small but statistically significant differences were detected in the levels of MBL. In contrast, the levels of two regulatory proteins of the alternative pathway varied widely between DF and DHF patients: DHF patients had higher levels of factor D (p = 0.01, which cleaves factor B to yield the active (C3bBb C3 convertase, and lower levels of factor H (p = 0.03, which inactivates the (C3bBb C3 convertase, than did DF patients. When we considered the levels of factors D and H together as an indicator of (C3bBb C3 convertase regulation, we found that the plasma levels of these regulatory proteins in DHF patients favored the formation of the (C3bBb C3 convertase, whereas its formation was inhibited in DF patients (p<0.0001. CONCLUSION: The data suggest that an imbalance in the levels of regulatory factors D and H is associated with an abnormal regulation of complement activity in DHF patients.

  6. Evasion Mechanisms Used by Pathogens to Escape the Lectin Complement Pathway

    Directory of Open Access Journals (Sweden)

    Anne Rosbjerg

    2017-05-01

    Full Text Available The complement system is a crucial defensive network that protects the host against invading pathogens. It is part of the innate immune system and can be initiated via three pathways: the lectin, classical and alternative activation pathway. Overall the network compiles a group of recognition molecules that bind specific patterns on microbial surfaces, a group of associated proteases that initiates the complement cascade, and a group of proteins that interact in proteolytic complexes or the terminal pore-forming complex. In addition, various regulatory proteins are important for controlling the level of activity. The result is a pro-inflammatory response meant to combat foreign microbes. Microbial elimination is, however, not a straight forward procedure; pathogens have adapted to their environment by evolving a collection of evasion mechanisms that circumvent the human complement system. Complement evasion strategies features different ways of exploiting human complement proteins and moreover features different pathogen-derived proteins that interfere with the normal processes. Accumulated, these mechanisms target all three complement activation pathways as well as the final common part of the cascade. This review will cover the currently known lectin pathway evasion mechanisms and give examples of pathogens that operate these to increase their chance of invasion, survival and dissemination.

  7. Complement-mediated solubilization of immune complexes and their interaction with complement C3 receptors

    DEFF Research Database (Denmark)

    Petersen, Ivan; Baatrup, Gunnar; Jepsen, H H;

    1985-01-01

    Some of the molecular events in the complement (C)-mediated solubilization of immune complexes (IC) have been clarified in recent years. The solubilization is primarily mediated by alternative C pathway proteins whereas factors in the classical pathway accelerate the process. Components of the me......Some of the molecular events in the complement (C)-mediated solubilization of immune complexes (IC) have been clarified in recent years. The solubilization is primarily mediated by alternative C pathway proteins whereas factors in the classical pathway accelerate the process. Components...

  8. Streptococcus pyogenes Endopeptidase O Contributes to Evasion from Complement-mediated Bacteriolysis via Binding to Human Complement Factor C1q.

    Science.gov (United States)

    Honda-Ogawa, Mariko; Sumitomo, Tomoko; Mori, Yasushi; Hamd, Dalia Talat; Ogawa, Taiji; Yamaguchi, Masaya; Nakata, Masanobu; Kawabata, Shigetada

    2017-03-10

    Streptococcus pyogenes secretes various virulence factors for evasion from complement-mediated bacteriolysis. However, full understanding of the molecules possessed by this organism that interact with complement C1q, an initiator of the classical complement pathway, remains elusive. In this study, we identified an endopeptidase of S. pyogenes, PepO, as an interacting molecule, and investigated its effects on complement immunity and pathogenesis. Enzyme-linked immunosorbent assay and surface plasmon resonance analysis findings revealed that S. pyogenes recombinant PepO bound to human C1q in a concentration-dependent manner under physiological conditions. Sites of inflammation are known to have decreased pH levels, thus the effects of PepO on bacterial evasion from complement immunity was analyzed in a low pH condition. Notably, under low pH conditions, PepO exhibited a higher affinity for C1q as compared with IgG, and PepO inhibited the binding of IgG to C1q. In addition, pepO deletion rendered S. pyogenes more susceptible to the bacteriocidal activity of human serum. Also, observations of the morphological features of the pepO mutant strain (ΔpepO) showed damaged irregular surfaces as compared with the wild-type strain (WT). WT-infected tissues exhibited greater severity and lower complement activity as compared with those infected by ΔpepO in a mouse skin infection model. Furthermore, WT infection resulted in a larger accumulation of C1q than that with ΔpepO. Our results suggest that interaction of S. pyogenes PepO with C1q interferes with the complement pathway, which enables S. pyogenes to evade complement-mediated bacteriolysis under acidic conditions, such as seen in inflammatory sites. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  9. Complement diagnostics: concepts, indications, and practical guidelines.

    Science.gov (United States)

    Nilsson, Bo; Ekdahl, Kristina Nilsson

    2012-01-01

    Aberrations in the complement system have been shown to be direct or indirect pathophysiological mechanisms in a number of diseases and pathological conditions such as autoimmune disease, infections, cancer, allogeneic and xenogeneic transplantation, and inflammation. Complement analyses have been performed on these conditions in both prospective and retrospective studies and significant differences have been found between groups of patients, but in many diseases, it has not been possible to make predictions for individual patients because of the lack of sensitivity and specificity of many of the assays used. The basic indications for serological diagnostic complement analysis today may be divided into three major categories: (a) acquired and inherited complement deficiencies; (b) disorders with complement activation; (c) inherited and acquired C1INH deficiencies. Here, we summarize indications, techniques, and interpretations for basic complement analyses and present an algorithm, which we follow in our routine laboratory.

  10. Complement Diagnostics: Concepts, Indications, and Practical Guidelines

    Directory of Open Access Journals (Sweden)

    Bo Nilsson

    2012-01-01

    Full Text Available Aberrations in the complement system have been shown to be direct or indirect pathophysiological mechanisms in a number of diseases and pathological conditions such as autoimmune disease, infections, cancer, allogeneic and xenogeneic transplantation, and inflammation. Complement analyses have been performed on these conditions in both prospective and retrospective studies and significant differences have been found between groups of patients, but in many diseases, it has not been possible to make predictions for individual patients because of the lack of sensitivity and specificity of many of the assays used. The basic indications for serological diagnostic complement analysis today may be divided into three major categories: (a acquired and inherited complement deficiencies; (b disorders with complement activation; (c inherited and acquired C1INH deficiencies. Here, we summarize indications, techniques, and interpretations for basic complement analyses and present an algorithm, which we follow in our routine laboratory.

  11. Role of complement in xenotransplantation.

    Science.gov (United States)

    Mollnes, Tom Eirik; Fiane, A E

    2002-01-01

    The xenotransplantation research is driven by the increasing gap between the number of patients with end-stage organ failure on waiting lists for transplantation and the supply of allografts. The lack of success in developing suitable artificial organs for permanent treatment of organ failure has further strengthened the need for xenotransplantation research. Pigs are now generally accepted to be the source animal of choice. Transplantation of pig organs to humans faces several barriers which have to be overcome before it comes to clinical application: (1) anatomical and physiological conditions; (2) immunological rejection mechanisms; (3) molecular compatibility between signal molecules of the two species; (4) risk of transmission of microorganisms, particularly pig endogenous retroviruses; and (5) legal and ethical aspects both with respect to the animal and the recipient. Here we will focus on the role of the complement system in the rejection of immediately vascularized pig-to-primate xenografts. The hyperacute rejection occurring within minutes after transplantation is mediated by binding of natural antibodies to the Galalpha(l-3)Gal epitope on the endothelial cells with subsequent complement activation. Whereas inhibition of complement activation protects against hyperacute rejection, the role of complement in the later rejection phases is less clarified.

  12. Reduction in erythrocyte-bound complement activation products and titres of anti-C1q antibodies associate with clinical improvement in systemic lupus erythematosus

    Science.gov (United States)

    Buyon, Jill; Furie, Richard; Putterman, Chaim; Ramsey-Goldman, Rosalind; Kalunian, Kenneth; Barken, Derren; Conklin, John; Dervieux, Thierry

    2016-01-01

    Background The relationship between cell-bound complement activation products (CB-CAPs: EC4d, EC3d), anti-C1q, soluble complement C3/C4 and disease activity in systemic lupus erythematosus (SLE) was evaluated. Methods Per protocol, at baseline all SLE subjects enrolled in this longitudinal study presented with active disease and elevated CB-CAPs. At each monthly visit, the non-serological (ns) Safety of Estrogens in Lupus Erythematosus: National Assessment (SELENA-SLEDAI) and the British Isles Lupus Assessment Group (BILAG)-2004 index scores were determined as was a random urinary protein to creatinine ratio (uPCR). Short-form 36 (SF-36) questionnaires were also collected. All soluble markers were determined using immunoassays, while EC4d and EC3d were determined using flow cytometry. Statistical analysis consisted of linear mixed models with random intercept and fixed slopes. Results A total of 36 SLE subjects (mean age 34 years; 94% female) were enrolled and evaluated monthly for an average 11 visits per subject. Clinical improvements were observed during the study, with significant decreases in ns-SELENA-SLEDAI scores, BILAG-2004 index scores and uPCR, and increases in all domains of SF-36 (p<0.01). The longitudinal decrease in ns-SELENA-SLEDAI and BILAG-2004 index scores was significantly associated with reduced EC4d and EC3d levels, reduced anti-C1q titres and increased serum complement C3/C4 (p<0.05). The changes in uPCR significantly correlated with C3, C4, anti-C1q and EC4d, with EC4d outperforming C3/C4 by a multivariate analysis. The reduced EC4d or EC3d was associated with improvements in at least six out of the eight domains of SF-36 and outperformed C3/C4. Anti-dsDNA titres did not correlate with changes in disease activity. Conclusions These data indicate that CB-CAPs and anti-C1q are helpful in monitoring patients with SLE. PMID:27752336

  13. Prednisolone has a positive effect on the kidney but not on the liver of brain dead rats: a potencial role in complement activation.

    Science.gov (United States)

    Rebolledo, Rolando; Liu, Bo; Akhtar, Mohammed Z; Ottens, Petra J; Zhang, Jian-ning; Ploeg, Rutger J; Leuvenink, Henri G D

    2014-05-02

    Contradictory evidence has been published on the effects of steroid treatments on the outcomes of kidney and liver transplantation from brain dead (BD) donors. Our study aimed to evaluate this disparity by investigating the effect of prednisolone administration on BD rats. BD induction was performed in ventilated rats by inflating a Fogarty catheter placed in the epidural space. Prednisolone (22.5 mg/kg) was administered 30 min prior to BD induction. After four hours of determination of BD: serum, kidney and liver tissues samples were collected and stored. RT-qPCR, routine biochemistry and immunohistochemistry were performed. Prednisolone treatment reduced circulating IL-6 and creatinine plasma levels but not serum AST, ALT or LDH. Polymorphonuclear influx assessed by histology, and inflammatory gene expression were reduced in the kidney and liver. However, complement component 3 (C3) expression was decreased in kidney but not in liver. Gene expression of HSP-70, a cytoprotective protein, was down-regulated in the liver after treatment. This study shows that prednisolone decreases inflammation and improves renal function, whilst not reducing liver injury. The persistence of complement activation and the negative effect on protective cellular mechanisms in the liver may explain the disparity between the effects of prednisolone on the kidney and liver of BD rats. The difference in the molecular and cellular responses to prednisolone administration may explain the contradictory evidence of the effects of prednisolone on different organ types from brain dead organ donors.

  14. Complement defects in patients with chronic rhinosinusitis.

    Directory of Open Access Journals (Sweden)

    Maria Q Gaunsbaek

    Full Text Available The complement system is an important part of our immune system, and complement defects lead generally to increased susceptibility to infections and autoimmune diseases. We have studied the role of complement activity in relation with chronic rhinosinusitis (CRS, and more specifically studied whether complement defects collectively predispose individuals for CRS or affect CRS severity. The participants comprised 87 CRS patients randomly selected from the general population, and a control group of 150 healthy blood donors. The CRS patients were diagnosed according to the European Position Paper on Rhinosinusitis and nasal Polyps criteria, and severity was evaluated by the Sino-nasal Outcome Test-22. Serum samples were analysed by ELISA for activity of the respective pathways of complement, and subsequently for serum levels of relevant components. We found that the frequency of complement defects was significantly higher among CRS patients than among healthy control subjects. A majority of Mannan-binding lectin deficient CRS patients was observed. The presence of complement defects had no influence on the severity of subjective symptoms. Our studies show that defects in the complement system collectively may play an immunological role related to the development of CRS. However, an association between severity of symptoms and presence of complement defects could not be demonstrated.

  15. Substitution of a single amino acid (aspartic acid for histidine) converts the functional activity of human complement C4B to C4A

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, M.C.; Fathallah, D.M.; Bergamaschini, L.; Alicot, E.M. (Harvard Medical School, Boston, MA (USA)); Isenman, D.E. (Univ. of Toronto, Ontario (Canada))

    1990-09-01

    The C4B isotype of the fourth component of human complement (C4) displays 3- to 4-fold greater hemolytic activity than does its other isotype C4A. This correlates with differences in their covalent binding efficiencies to erythrocytes coated with antibody and complement C1. C4A binds to a greater extent when C1 is on IgG immune aggregates. The differences in covalent binding properties correlate only with amino acid changes between residues 1101 and 1106 (pro-C4 numbering)-namely, Pro-1101, Cys-1102, Leu-1105, and Asp-1106 in C4A and Leu-1101, Ser-1102, Ile-1105, and His-1106 in C4B, which are located in the C4d region of the {alpha} chain. To more precisely identify the residues that are important for the functional differences, C4A-C4B hybrid proteins were constructed by using recombinant DNA techniques. Comparison of these by hemolytic assay and binding to IgG aggregates showed that the single substitution of aspartic acid for histidine at position 1106 largely accounted for the change in functional activity and nature of the chemical bond formed. Surprisingly, substitution of a neutral residue, alanine, for histidine at position 1106 resulted in an increase in binding to immune aggregates without subsequent reduction in the hemolytic activity. This result strongly suggests that position 1106 is not catalytic as previously proposed but interacts sterically/electrostatically with potential acceptor sites and serves to select binding sites on potential acceptor molecules.

  16. TMA: beware of complements.

    Science.gov (United States)

    Ricklin, Daniel; Cines, Douglas B

    2013-09-19

    In this issue of Blood, Jodele and colleagues report that defective complement regulation contributes to the development of thrombotic microangiopathy (TMA) after hematopoietic stem cell transplantation (HSCT) with important implications for diagnosis and management of this severe clinical complication.

  17. Classical antiparticles

    Energy Technology Data Exchange (ETDEWEB)

    Costella, J.P.; McKellar, B.H.J.; Rawlinson, A.A.

    1997-03-01

    We review how antiparticles may be introduced in classical relativistic mechanics, and emphasize that many of their paradoxical properties can be more transparently understood in the classical than in the quantum domain. (authors). 13 refs., 1 tab.

  18. Classical antiparticles

    CERN Document Server

    Costella, J P; Rawlinson, A A; Costella, John P.; Kellar, Bruce H. J. Mc; Rawlinson, Andrew A.

    1997-01-01

    We review how antiparticles may be introduced in classical relativistic mechanics, and emphasize that many of their paradoxical properties can be more transparently understood in the classical than in the quantum domain.

  19. Milk immunoglobulins and complement factors.

    Science.gov (United States)

    Korhonen, H; Marnila, P; Gill, H S

    2000-11-01

    The importance of colostrum for the growth and health of newborn offspring is well known. In bovine colostrum, the antibody (immunoglobulin) complement system provides a major antimicrobial effect against a wide range of microbes and confers passive immunity until the calf's own immune system has matured. Bovine serum and lacteal secretions contain three major classes of immunoglobulins: IgG, IgM and IgA. The immunoglobulins are selectively transported from the serum into the mammary gland, as a result of which the first colostrum contains very high concentrations of immunoglobulins (40-200 mg/ml). IgG1 accounts for over 75 % of the immunoglobulins in colostral whey, followed by IgM, IgA and IgG2. All these immunoglobulins decrease within a few days to a total immunoglobulin concentration of 0.7-1.0 mg/ml, with IgG1 representing the major Ig class in milk throughout the lactation period. Together with the antibodies absorbed from colostrum after birth, the complement system plays a crucial role in the passive immunisation of the newborn calf. The occurrence of haemolytic or bactericidal complement activity in bovine colostrum and milk has been demonstrated in several studies. This review deals with the characteristics of bovine Igs and the complement system to be exploited as potential ingredients for health-promoting functional foods.

  20. Local neutrophil influx following lateral fluid-percussion brain injury in rats is associated with accumulation of complement activation fragments of the third component (C3) of the complement system.

    Science.gov (United States)

    Keeling, K L; Hicks, R R; Mahesh, J; Billings, B B; Kotwal, G J

    2000-06-01

    Traumatic brain injury can lead to locally destructive secondary events mediated by several inflammatory components. Following lateral fluid-percussion (FP) brain injury in rats, we examined cortical and hippocampal sections for neutrophil infiltration and accumulation of complement component C3. Neutrophil influx into the brain after injury was detected by an improved myeloperoxidase (MPO) microassay and manual cell counting, while C3 accumulation was detected using immunocytochemistry. MPO levels were elevated in the injured cortical tissue, whereas C3 immunoreactivity was increased in both injured cortical and ipsilateral hippocampal sections. These results show that the FP model of head injury leads to an intense local inflammatory reaction and subsequent tissue destruction.

  1. T helper 1 immunity requires complement-driven NLRP3 inflammasome activity in CD4⁺ T cells.

    Science.gov (United States)

    Arbore, Giuseppina; West, Erin E; Spolski, Rosanne; Robertson, Avril A B; Klos, Andreas; Rheinheimer, Claudia; Dutow, Pavel; Woodruff, Trent M; Yu, Zu Xi; O'Neill, Luke A; Coll, Rebecca C; Sher, Alan; Leonard, Warren J; Köhl, Jörg; Monk, Pete; Cooper, Matthew A; Arno, Matthew; Afzali, Behdad; Lachmann, Helen J; Cope, Andrew P; Mayer-Barber, Katrin D; Kemper, Claudia

    2016-06-17

    The NLRP3 inflammasome controls interleukin-1β maturation in antigen-presenting cells, but a direct role for NLRP3 in human adaptive immune cells has not been described. We found that the NLRP3 inflammasome assembles in human CD4(+) T cells and initiates caspase-1-dependent interleukin-1β secretion, thereby promoting interferon-γ production and T helper 1 (T(H)1) differentiation in an autocrine fashion. NLRP3 assembly requires intracellular C5 activation and stimulation of C5a receptor 1 (C5aR1), which is negatively regulated by surface-expressed C5aR2. Aberrant NLRP3 activity in T cells affects inflammatory responses in human autoinflammatory disease and in mouse models of inflammation and infection. Our results demonstrate that NLRP3 inflammasome activity is not confined to "innate immune cells" but is an integral component of normal adaptive T(H)1 responses.

  2. The down-stream effects of mannan-induced lectin complement pathway activation depend quantitatively on alternative pathway amplification

    DEFF Research Database (Denmark)

    Harboe, Morten; Garred, Peter; Karlstrøm, Ellen

    2009-01-01

    was not observed even at high mannan concentrations since addition of the inhibiting anti-MBL mAb 3F8 completely abolished generation of the terminal C5b-9 complex (TCC). However, selective blockade of AP by anti-factor D inhibited more than 80% of TCC release into the fluid phase after LP activation showing...... that AP amplification is quantitatively responsible for the final effect of initial specific LP activation. TCC generation on the solid phase was distinctly but less inhibited by anti-fD. C2 bypass of the LP pathway could be demonstrated, and AP amplification was also essential during C2 bypass in LP...... as shown by complete inhibition of TCC generation in C2-deficient serum by anti-fD and anti-properdin antibodies. In conclusion, the down-stream effect of LP activation depends strongly on AP amplification in normal human serum and in the C2 bypass pathway....

  3. Specific, sensitive, precise, and rapid functional chromogenic assay of activated first complement component (C1) in plasma

    DEFF Research Database (Denmark)

    Munkvad, S; Jespersen, J; Sidelmann, Johannes Jakobsen;

    1990-01-01

    by using an amidolytic rate assay with a chromogenic substrate. We have optimized the assay conditions with respect to incubation time, concentration of antiserum to C1-inh, ionic strength, and pH. Our method determines specifically the concentration in plasma of free activated C1, not complexes...

  4. Cryptic residual GALT activity is a potential modifier of scholastic outcome in school age children with classic galactosemia.

    Science.gov (United States)

    Ryan, Emily L; Lynch, Mary Ellen; Taddeo, Elles; Gleason, Tyler J; Epstein, Michael P; Fridovich-Keil, Judith L

    2013-11-01

    Classic galactosemia is a potentially lethal disorder that results from profound deficiency of galactose-1-phosphate uridylyltransferase (GALT), the second enzyme in the Leloir pathway of galactose metabolism. Although early diagnosis and rigorous dietary restriction of galactose prevent or resolve the potentially lethal acute symptoms, patients are at markedly increased risk of long-term complications including significant cognitive, speech, and behavioral difficulties, among other problems. The mechanisms that underlie these long-term complications remain unclear, as do the factors that modify their severity. Here we explored the scholastic and behavioral outcomes experienced by a cohort of 54 school age children with classic galactosemia. Data collected included survey responses from parents and teachers, school records including standardized test scores, and GALT genotype data used to estimate predicted residual GALT activity based on a yeast expression system. As expected, many but not all of the children in our study demonstrated speech, scholastic, and behavioral difficulties. Perhaps most striking, we found that predicted cryptic residual GALT activity, often below the threshold of detection of clinical assays, appeared to modify scholastic outcome. These data raise the intriguing possibility that cryptic GALT activity might also influence the severity of other long-term complications in classic galactosemia.

  5. The role of complement in AMD.

    Science.gov (United States)

    Zipfel, Peter F; Lauer, Nadine; Skerka, Christine

    2010-01-01

    Age related macular degeneration (AMD) is a common form of blindness in the western world and genetic variations of several complement genes, including the complement regulator Factor H, the central complement component C3, Factor B, C2, and also Factor I confer a risk for the disease. However deletion of a chromosomal segment in the Factor H gene cluster on human chromosome 1, which results in the deficiency of the terminal pathway regulator CFHR1, and of the putative complement regulator CFHR3 has a protective effect for development of AMD. The Factor H gene encodes two proteins Factor H and FHL1 which are derived from alternatively processed transcripts. In particular a sequence variation at position 402 of both Factor H and FHL1 is associated with a risk for AMD. A tyrosine residue at position 402 represents the protective and a histidine residue the risk variant. AMD is considered a chronic inflammatory disease, which can be caused by defective and inappropriate regulation of the continuously activated alternative complement pathway. This activation generates complement effector products and inflammatory mediators that stimulate further inflammatory reactions. Defective regulation can lead to formation of immune deposits, drusen and ultimately translate into damage of retinal pigment epithelial cells, rupture of the interface between these epithelial cells and the Bruch's membrane and vision loss. Here we describe the role of complement in the retina and summarize the current concept how defective or inappropriate local complement control contributes to inflammation and the pathophysiology of AMD.

  6. Finite Complements in English

    Institute of Scientific and Technical Information of China (English)

    Ronald W. Langacker

    2008-01-01

    This paper explores the conceptual basis of finite complimentation in English.It first considem the distinguishing property of a finite clause,namely grounding,effeeted by tense and the modals.Notions crucial for clausal grounding--including a reality conception and the striving for control at the effective and epistemic levelsalso figure in the semantic import of eomplementation.An essential feature of complement constructions is the involvement of multiple conceptualizers,each with their own conception of reality.The different types of complement and their grammatical markings can be characterized on this basis.Finite complements differ from other types by virtue of expressing an autonomous proposition capable of being apprehended by multiple conceptualizers,each from their own vantage point.Acognitive model representing phases in the striving for epistemic control provides a partial basis for the semantic description of predicates taking finite complements.The same model supports the description of both personal and impersonal complement constructions.

  7. Role of complement receptor 1 (CR1; CD35) on epithelial cells: A model for understanding complement-mediated damage in the kidney.

    Science.gov (United States)

    Java, Anuja; Liszewski, M Kathryn; Hourcade, Dennis E; Zhang, Fan; Atkinson, John P

    2015-10-01

    The regulators of complement activation gene cluster encodes a group of proteins that have evolved to control the amplification of complement at the critical step of C3 activation. Complement receptor 1 (CR1) is the most versatile of these inhibitors with both receptor and regulatory functions. While expressed on most peripheral blood cells, the only epithelial site of expression in the kidney is by the podocyte. Its expression by this cell population has aroused considerable speculation as to its biologic function in view of many complement-mediated renal diseases. The goal of this investigation was to assess the role of CR1 on epithelial cells. To this end, we utilized a Chinese hamster ovary cell model system. Among our findings, CR1 reduced C3b deposition by ∼ 80% during classical pathway activation; however, it was an even more potent regulator (>95% reduction in C3b deposition) of the alternative pathway. This inhibition was primarily mediated by decay accelerating activity. The deposited C4b and C3b were progressively cleaved with a t½ of ∼ 30 min to C4d and C3d, respectively, by CR1-dependent cofactor activity. CR1 functioned intrinsically (i.e, worked only on the cell on which it was expressed). Moreover, CR1 efficiently and stably bound but didn't internalize C4b/C3b opsonized immune complexes. Our studies underscore the potential importance of CR1 on an epithelial cell population as both an intrinsic complement regulator and an immune adherence receptor. These results provide a framework for understanding how loss of CR1 expression on podocytes may contribute to complement-mediated damage in the kidney.

  8. The Anticomplementary Activity of ’Fusobacterium polymorphum’ in Normal and C-4 Deficient Sources of Guinea Pig Complement.

    Science.gov (United States)

    1977-01-12

    Dentistry A U University of Maryland * Baltimore, Maryland. 21201 Short Title.: Anticoinplementary Activity of F. poiymorphwn 1. Present Address...C-4 Deficient GP sera (C4D). The C4D was kindly provided by Dr. Jerry A. Winkelstein, Depart- ment of Pediatrics , The Johns Hopkins School of...Plaque on Epoxy Resin Crowns in Man. 3. Periodontol. 46: 10—26. S ! S ~ L 5- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 20a

  9. STYLE ACTIVITIES SEEN IN THE MEANING DOMAIN OF XVII. CENTURY CLASSIC TURKISH POETRY: CLASSICAL STYLE-SEBK-İ HİNDÎ-HİKEMÎ TARZ- LOCALIZATION

    Directory of Open Access Journals (Sweden)

    Assoc. Prof. Dr. Sener DEMİREL

    2009-04-01

    Full Text Available XVII. century corresponds to a period called“Middle Classic Period” by literature historians, a periodwhere the Classic Turkish poetry was at the peak of itsmaturity. This period is also interesting, because it is aperiod that contains different styles/tastes feeding fromthe same source in Turkish poetry. It is a well known factthat until the XVII. century, there wasn’t a seriousseparation between the words and meaning in ClassicTurkish poetry, and some poets were considered betterthan the others by personal preferences, but this hasnever became a generally accepted idea. However,especially at the end of the XVI. century and beginning ofthe XVII. century, with the effect of Sebk-i Hindi, firstseen in Iran, India and then Divan poetry and based onhidden, concealed and complex meaning, some importantchanges were seen in the meaning domain of Turkishpoetry. In the same century, a new formation calledHikemi Tarz, known as Nabi school and prioritizesthoughts and wisdom in poetry, has shown its effect inliterature history. This new style was also based on themeaning like Sebk-i Hindi, but was interested in theconcrete side of the meaning; in other words thoughts.The poets influenced by this new style have opened a newwindow in classic poetry and tried to enrich the meaningdimension of poetry by thought axis. In this paper, the changes and developments inthe meaning domain of Turkish poetry caused by Classicstyle, Sebk-i Hindi, Hikemi Tarz and Localization poetry,seem on classic Turkish poetry in the XVII. and XVIII.centuries, will tried to be examined in sample versestaken from the poems of the poets representing thoseperiods.

  10. Local inflammation induces complement crosstalk which amplifies the antimicrobial response.

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    2009-01-01

    Full Text Available By eliciting inflammatory responses, the human immunosurveillance system notably combats invading pathogens, during which acute phase proteins (CRP and cytokines are elevated markedly. However, the Pseudomonas aeruginosa is a persistent opportunistic pathogen prevalent at the site of local inflammation, and its acquisition of multiple antibiotic-resistance factors poses grave challenges to patient healthcare management. Using blood samples from infected patients, we demonstrate that P. aeruginosa is effectively killed in the plasma under defined local infection-inflammation condition, where slight acidosis and reduced calcium levels (pH 6.5, 2 mM calcium typically prevail. We showed that this powerful antimicrobial activity is provoked by crosstalk between two plasma proteins; CRPratioL-ficolin interaction led to communication between the complement classical and lectin pathways from which two amplification events emerged. Assays for C4 deposition, phagocytosis, and protein competition consistently proved the functional significance of the amplification pathways in boosting complement-mediated antimicrobial activity. The infection-inflammation condition induced a 100-fold increase in CRPratioL-ficolin interaction in a pH- and calcium-sensitive manner. We conclude that the infection-induced local inflammatory conditions trigger a strong interaction between CRPratioL-ficolin, eliciting complement-amplification pathways which are autonomous and which co-exist with and reinforce the classical and lectin pathways. Our findings provide new insights into the host immune response to P. aeruginosa infection under pathological conditions and the potential development of new therapeutic strategies against bacterial infection.

  11. Genetic, molecular and functional analyses of complement factor I deficiency

    DEFF Research Database (Denmark)

    Nilsson, S.C.; Trouw, L.A.; Renault, N.;

    2009-01-01

    Complete deficiency of complement inhibitor factor I (FI) results in secondary complement deficiency due to uncontrolled spontaneous alternative pathway activation leading to susceptibility to infections. Current genetic examination of two patients with near complete FI deficiency and three...

  12. Crosstalk between Complement and Toll-like Receptor Activation in Relation to Donor Brain Death and Renal Ischemia-Reperfusion Injury

    NARCIS (Netherlands)

    Damman, Jeffrey; Daha, Mohamed R.; van Son, Willem J.; Leuvenink, Henri G.; Ploeg, Rutger J.; Seelen, Marc A.

    2011-01-01

    Two central pathways of innate immunity, complement and Toll-like receptors (TLRs), play an important role in the pathogenesis of renal injury inherent to kidney transplantation. Recent findings indicate close crosstalk between complement and TLR signaling pathways. It is suggested that mitogen acti

  13. Crosstalk between Complement and Toll-like Receptor Activation in Relation to Donor Brain Death and Renal Ischemia-Reperfusion Injury

    NARCIS (Netherlands)

    Damman, Jeffrey; Daha, Mohamed R.; van Son, Willem J.; Leuvenink, Henri G.; Ploeg, Rutger J.; Seelen, Marc A.

    2011-01-01

    Two central pathways of innate immunity, complement and Toll-like receptors (TLRs), play an important role in the pathogenesis of renal injury inherent to kidney transplantation. Recent findings indicate close crosstalk between complement and TLR signaling pathways. It is suggested that mitogen acti

  14. New general pore size distribution model by classical thermodynamics application: Activated carbon

    Science.gov (United States)

    Lordgooei, M.; Rood, M.J.; Rostam-Abadi, M.

    2001-01-01

    A model is developed using classical thermodynamics to characterize pore size distributions (PSDs) of materials containing micropores and mesopores. The thermal equation of equilibrium adsorption (TEEA) is used to provide thermodynamic properties and relate the relative pore filling pressure of vapors to the characteristic pore energies of the adsorbent/adsorbate system for micropore sizes. Pore characteristic energies are calculated by averaging of interaction energies between adsorbate molecules and adsorbent pore walls as well as considering adsorbate-adsorbate interactions. A modified Kelvin equation is used to characterize mesopore sizes by considering variation of the adsorbate surface tension and by excluding the adsorbed film layer for the pore size. The modified-Kelvin equation provides similar pore filling pressures as predicted by density functional theory. Combination of these models provides a complete PSD of the adsorbent for the micropores and mesopores. The resulting PSD is compared with the PSDs from Jaroniec and Choma and Horvath and Kawazoe models as well as a first-order approximation model using Polanyi theory. The major importance of this model is its basis on classical thermodynamic properties, less simplifying assumptions in its derivation compared to other methods, and ease of use.

  15. A Preliminary Study on Hemolytic Activity of the Complement B Factor ofApostichopusjaponicusin vivo%仿刺参补体B因子溶血活性初步研究

    Institute of Scientific and Technical Information of China (English)

    钟磊; 张峰; 毕颖

    2011-01-01

    本文应用高等哺乳动物血清补体B因子溶血检测技术检测仿刺参个体体内补体B因子。通过溶血法检测了健康仿刺参以及人工诱导化皮仿刺参体腔液补体B因子活性。结果显示仿刺参体腔液有补体B因子存在,且含补体B因子仿刺参体腔液溶血活性明显高于去补体B因子体腔液的溶血活性。实验对仿刺参体腔液进行加热处理结果显示其补体B因子是对热不稳定的分子,此特性与高等哺乳动物B因子特征相同。仿刺参体内存在补体B因子,它与脊椎动物补体B因子性质相似,在免疫旁路途径中起重要作用。%In this paper, the method of mammals hemolytic serum for complement factor B test was used to detect the complement B factor of Apostichopus japonicusin vivo. The complement factor B activity in celomocytes fluid of health and skin ulcers of Apostichopus japonicus was detected. The results showed that the sea cucumber body fluid with the existence of complement factor B, containing the sea cucumber complement factor B hemolytic activity of body fluid was higher than that and to complement factor B hemolytic activity of body fluid. Experiments on sea cucumber body fluid to heat treatment showed that its complement factor B is the thermal instability of the molecule, this characteristic and higher mammals, B factor are identical. Complement B factors exists in sea cucumber body, and it play an important role in alternative pathway of complement, similar as vertebrate Complement B factor.

  16. Active control on high-order coherence and statistic characterization on random phase fluctuation of two classical point sources.

    Science.gov (United States)

    Hong, Peilong; Li, Liming; Liu, Jianji; Zhang, Guoquan

    2016-03-29

    Young's double-slit or two-beam interference is of fundamental importance to understand various interference effects, in which the stationary phase difference between two beams plays the key role in the first-order coherence. Different from the case of first-order coherence, in the high-order optical coherence the statistic behavior of the optical phase will play the key role. In this article, by employing a fundamental interfering configuration with two classical point sources, we showed that the high- order optical coherence between two classical point sources can be actively designed by controlling the statistic behavior of the relative phase difference between two point sources. Synchronous position Nth-order subwavelength interference with an effective wavelength of λ/M was demonstrated, in which λ is the wavelength of point sources and M is an integer not larger than N. Interestingly, we found that the synchronous position Nth-order interference fringe fingerprints the statistic trace of random phase fluctuation of two classical point sources, therefore, it provides an effective way to characterize the statistic properties of phase fluctuation for incoherent light sources.

  17. Complement and thrombosis in the antiphospholipid syndrome.

    Science.gov (United States)

    Oku, Kenji; Nakamura, Hiroyuki; Kono, Michihiro; Ohmura, Kazumasa; Kato, Masaru; Bohgaki, Toshiyuki; Horita, Tetsuya; Yasuda, Shinsuke; Amengual, Olga; Atsumi, Tatsuya

    2016-10-01

    The involvement of complement activation in the pathophysiology of antiphospholipid syndrome (APS) was first reported in murine models of antiphospholipid antibody (aPL)-related pregnancy morbidities. We previously reported that complement activation is prevalent and may function as a source of procoagulant cell activation in the sera of APS patients. Recently, autoantibodies against C1q, a component of complement 1, were reported to be correlated with complement activation in systemic lupus erythematosus. These antibodies target neoepitopes of deformed C1q bound to various molecules (i.e., anionic phospholipids) and induce accelerated complement activation. We found that anti-C1q antibodies are more frequently detected in primary APS patients than in control patients and in refractory APS patients with repeated thrombotic events. The titer of anti-C1q antibodies was significantly higher in refractory APS patients than in APS patients without flare. The binding of C1q to anionic phospholipids may be associated with the surge in complement activation in patients with anti-C1q antibodies when triggered by 'second-hit' biological stressors such as infection. Such stressors will induce overexpression of anionic phospholipids, with subsequent increases in deformed C1q that is targeted by anti-C1q antibodies.

  18. Mouse Ficolin B Has an Ability to Form Complexes with Mannose-Binding Lectin-Associated Serine Proteases and Activate Complement through the Lectin Pathway

    Directory of Open Access Journals (Sweden)

    Yuichi Endo

    2012-01-01

    Full Text Available Ficolins are thought to be pathogen-associated-molecular-pattern-(PAMP- recognition molecules that function to support innate immunity. Like mannose-binding lectins (MBLs, most mammalian ficolins form complexes with MBL-associated serine proteases (MASPs, leading to complement activation via the lectin pathway. However, the ability of murine ficolin B, a homologue of human M-ficolin, to perform this function is still controversial. The results of the present study show that ficolin B in mouse bone marrow is an oligomeric protein. Ficolin B, pulled down using GlcNAc-agarose, contained very low, but detectable, amounts of MASP-2 and small MBL-associated protein (sMAP and showed detectable C4-deposition activity on immobilized N-acetylglucosamine. These biochemical features of ficolin B were confirmed using recombinant mouse ficolin B produced in CHO cells. Taken together, these results suggest that like other mammalian homologues, murine ficolin B has an ability to exert its function via the lectin pathway.

  19. Age-related macular degeneration: Complement in action.

    Science.gov (United States)

    van Lookeren Campagne, Menno; Strauss, Erich C; Yaspan, Brian L

    2016-06-01

    The complement system plays a key role in host-defense against common pathogens but must be tightly controlled to avoid inflammation and tissue damage. Polymorphisms in genes encoding two important negative regulators of the alternative complement pathway, complement factor H (CFH) and complement factor I (CFI), are associated with the risk for Age-Related Macular Degeneration (AMD), a leading cause of vision impairment in the ageing population. In this review, we will discuss the genetic basis of AMD and the potential impact of complement de-regulation on disease pathogenesis. Finally, we will highlight recent therapeutic approaches aimed at controlling complement activation in patients with AMD.

  20. Complement in therapy and disease: Regulating the complement system with antibody-based therapeutics.

    Science.gov (United States)

    Melis, Joost P M; Strumane, Kristin; Ruuls, Sigrid R; Beurskens, Frank J; Schuurman, Janine; Parren, Paul W H I

    2015-10-01

    Complement is recognized as a key player in a wide range of normal as well as disease-related immune, developmental and homeostatic processes. Knowledge of complement components, structures, interactions, and cross-talk with other biological systems continues to grow and this leads to novel treatments for cancer, infectious, autoimmune- or age-related diseases as well as for preventing transplantation rejection. Antibodies are superbly suited to be developed into therapeutics with appropriate complement stimulatory or inhibitory activity. Here we review the design, development and future of antibody-based drugs that enhance or dampen the complement system.

  1. Periodontitis promotes the diabetic development of obese rat via miR-147 induced classical macrophage activation.

    Science.gov (United States)

    Xu, Ran; Zeng, Guang; Wang, Shuyong; Tao, Hong; Ren, Le; Zhang, Zhe; Zhang, Qingna; Zhao, Jinxiu; Gao, Jing; Li, Daxu

    2016-10-01

    Emerging evidence has indicated the bad effect of periodontal inflammation on diabetes control. However, the exact regulatory mechanisms within the association between periodontitis and diabetic development remain unclear. This study aims to investigate the function of microRNAs in regulating periodontitis-induced inflammation in an obese rat model. Experimental periodontitis was introduced into OLETF and LETO rat. Intraperitoneal glucose tolerance test was performed to detect diabetic development. Serum cytokines levels and microRNAs expression were detected by ELISA and RT-PCR analysis respectively. And, macrophages were isolated for gain- and loss-of-function studies, to investigate the regulatory mechanism of miR-147 in periodontitis-induced inflammation. Periodontitis induced proinflammatory response with classical activated macrophages in both rats, but distinctively aggravated the impaired glucose tolerance of OLETF rat with spontaneous type 2 diabetes. Analysis for serum microRNAs expression showed the distinctive and synergistic upregulation of miR-147 with periodontitis-induced effects in rats, while further experiments demonstrated the positive regulatory mechanism of miR-147 on classical activated macrophages with overexpressed proinflammatory markers, showing M1 phenotype. This study provided new evidence for the positive effect of periodontal inflammation on diabetic development, while the regulatory mechanism of miR-147 on classical macrophage activation, was verified, and presumed to contribute to the impaired glucose tolerance aggravated by periodontitis in obese rats. Besides, this study indicated the application of miR-147 for therapeutic approach in the treatment of diabetes with periodontitis. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  2. A metalloproteinase mirolysin of Tannerella forsythia inhibits all pathways of the complement system

    Science.gov (United States)

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

    2015-01-01

    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. Here 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, while 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

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

    Science.gov (United States)

    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.

  4. Classics Online.

    Science.gov (United States)

    Clayman, Dee L.

    1995-01-01

    Appraises several databases devoted to classical literature. Thesaurus Linguae Graecae (TLG) contains the entire extant corpus of ancient Greek literature, including works on lexicography and historiography, extending into the 15th century. Other works awaiting completion are the Database of Classical Bibliography and a CD-ROM pictorial dictionary…

  5. Classical integrability

    Science.gov (United States)

    Torrielli, Alessandro

    2016-08-01

    We review some essential aspects of classically integrable systems. The detailed outline of the sections consists of: 1. Introduction and motivation, with historical remarks; 2. Liouville theorem and action-angle variables, with examples (harmonic oscillator, Kepler problem); 3. Algebraic tools: Lax pairs, monodromy and transfer matrices, classical r-matrices and exchange relations, non-ultralocal Poisson brackets, with examples (non-linear Schrödinger model, principal chiral field); 4. Features of classical r-matrices: Belavin-Drinfeld theorems, analyticity properties, and lift of the classical structures to quantum groups; 5. Classical inverse scattering method to solve integrable differential equations: soliton solutions, spectral properties and the Gel’fand-Levitan-Marchenko equation, with examples (KdV equation, Sine-Gordon model). Prepared for the Durham Young Researchers Integrability School, organised by the GATIS network. This is part of a collection of lecture notes.

  6. Mesenchymal stromal cells engage complement and complement receptor bearing innate effector cells to modulate immune responses.

    Directory of Open Access Journals (Sweden)

    Guido Moll

    Full Text Available Infusion of human third-party mesenchymal stromal cells (MSCs appears to be a promising therapy for acute graft-versus-host disease (aGvHD. To date, little is known about how MSCs interact with the body's innate immune system after clinical infusion. This study shows, that exposure of MSCs to blood type ABO-matched human blood activates the complement system, which triggers complement-mediated lymphoid and myeloid effector cell activation in blood. We found deposition of complement component C3-derived fragments iC3b and C3dg on MSCs and fluid-phase generation of the chemotactic anaphylatoxins C3a and C5a. MSCs bound low amounts of immunoglobulins and lacked expression of complement regulatory proteins MCP (CD46 and DAF (CD55, but were protected from complement lysis via expression of protectin (CD59. Cell-surface-opsonization and anaphylatoxin-formation triggered complement receptor 3 (CD11b/CD18-mediated effector cell activation in blood. The complement-activating properties of individual MSCs were furthermore correlated with their potency to inhibit PBMC-proliferation in vitro, and both effector cell activation and the immunosuppressive effect could be blocked either by using complement inhibitor Compstatin or by depletion of CD14/CD11b-high myeloid effector cells from mixed lymphocyte reactions. Our study demonstrates for the first time a major role of the complement system in governing the immunomodulatory activity of MSCs and elucidates how complement activation mediates the interaction with other immune cells.

  7. Urinary excretion of the C5b-9 membrane attack complex of complement is a marker of immune disease activity in autologous immune complex nephritis.

    Science.gov (United States)

    Pruchno, C J; Burns, M M; Schulze, M; Johnson, R J; Baker, P J; Alpers, C E; Couser, W G

    1991-01-01

    The urinary excretion of the C5b-9 membrane attack complex of complement correlates with glomerular deposition of antibody in the passive Heymann nephritis (PHN) model of membranous nephropathy (MN). To determine if this parameter can be correlated with antibody deposition in a model of MN induced by an autologous mechanism and thus more analogous to human MN, the relationship of urinary C5b-9 to ongoing glomerular immune complex formation late in autologous immune complex nephritis (AICN) was studied. Based on urinary C5b-9, the animals were divided into two groups at 12 weeks after induction of AICN, those with persistently high urinary C5b-9 excretion and those in whom urinary excretion of C5b-9 returned to undetectable levels. While all rats developed glomerular deposition of rat IgG and significant proteinuria, high C5b-9 excretors had greater proteinuria and prolonged positive staining for glomerular C3. When normal syngeneic kidneys were transplanted into rats (n = 3) from each group, only those with persistent C5b-9 excretion developed subepithelial immune deposits of rat IgG in the transplanted kidney. As in the PHN model of MN, proteinuria was dissociated widely from urinary C5b-9 excretion, glomerular C3 staining, and evidence of circulating antibody. Thus these findings demonstrate that urinary excretion of C5b-9 serves as an index of on-going immunologic disease activity in the AICN model of MN, while proteinuria does not.

  8. A single-CRD C-type lectin from oyster Crassostrea gigas mediates immune recognition and pathogen elimination with a potential role in the activation of complement system.

    Science.gov (United States)

    Li, Hui; Zhang, Huan; Jiang, Shuai; Wang, Weilin; Xin, Lusheng; Wang, Hao; Wang, Lingling; Song, Linsheng

    2015-06-01

    C-type lectins (CTLs), serving as pattern recognition receptors (PRRs), are a superfamily of Ca(2+)-dependent carbohydrate-recognition proteins that participate in nonself-recognition and pathogen elimination. In the present study, a single carbohydrate-recognition domain (CRD) CTL was identified from oyster Crassostrea gigas (designated as CgCLec-2). There was only one CRD within the deduced amino acid sequence of CgCLec-2 consisting of 129 amino acid residues. A conserved EPN (Glu246-Pro247-Asn248) motif was found in Ca(2+)-binding site 2 of CgCLec-2. The CgCLec-2 mRNA could be detected in all the examined tissues at different expression levels in oysters. The mRNA expression of CgCLec-2 in hemocytes was up-regulated significantly at 6 h post Vibrio splendidus challenge. The recombinant CgCLec-2 (rCgCLec-2) could bind various Pathogen-Associated Molecular Patterns (PAMPs), including lipopolysaccharide, mannan and peptidoglycan, and displayed strong binding abilities to Vibrio anguillarum, V. splendidus and Yarrowiali polytica and week binding ability to Staphylococcus aureus. It could also enhance the phagocytic activity of oyster hemocytes to V. splendidus and exhibited growth suppression activity against gram-positive bacteria S. aureus but no effect on gram-negative bacteria V. splendidus. Furthermore, the interaction between rCgCLec-2 and rCgMASPL-1 was confirmed by GST Pull down. The results suggested that CgCLec-2 served as not only a PRR in immune recognition but also a regulatory factor in pathogen elimination, and played a potential role in the activation of complement system.

  9. Autocrine Effects of Tumor-Derived Complement

    Directory of Open Access Journals (Sweden)

    Min Soon Cho

    2014-03-01

    Full Text Available We describe a role for the complement system in enhancing cancer growth. Cancer cells secrete complement proteins that stimulate tumor growth upon activation. Complement promotes tumor growth via a direct autocrine effect that is partially independent of tumor-infiltrating cytotoxic T cells. Activated C5aR and C3aR signal through the PI3K/AKT pathway in cancer cells, and silencing the PI3K or AKT gene in cancer cells eliminates the progrowth effects of C5aR and C3aR stimulation. In patients with ovarian or lung cancer, higher tumoral C3 or C5aR mRNA levels were associated with decreased overall survival. These data identify a role for tumor-derived complement proteins in promoting tumor growth, and they therefore have substantial clinical and therapeutic implications.

  10. Functional characterization of the lectin pathway of complement in human serum.

    Science.gov (United States)

    Roos, Anja; Bouwman, Lee H; Munoz, Jeric; Zuiverloon, Tahlita; Faber-Krol, Maria C; Fallaux-van den Houten, Francien C; Klar-Mohamad, Ngaisah; Hack, C Erik; Tilanus, Marcel G; Daha, Mohamed R

    2003-01-01

    Mannan-binding lectin (MBL) is a major initiator of the lectin pathway (LP) of complement. Polymorphisms in exon 1 of the MBL gene are associated with impaired MBL function and infections. Functional assays to assess the activity of the classical pathway (CP) and the alternative pathway (AP) of complement in serum are broadly used in patient diagnostics. We have now developed a functional LP assay that enables the specific quantification of autologous MBL-dependent complement activation in human serum. Complement activation was assessed by ELISA using coated mannan to assess the LP and coated IgM to assess the CP. Normal human serum (NHS) contains IgG, IgA and IgM antibodies against mannan, as shown by ELISA. These antibodies are likely to induce CP activation. Using C1q-blocking and MBL-blocking mAb, it was confirmed that both the LP and the CP contribute to complement activation by mannan. In order to quantify LP activity without interference of the CP, LP activity was measured in serum in the presence of C1q-blocking Ab. Activation of serum on coated IgM via the CP resulted in a dose-dependent deposition of C1q, C4, C3, and C5b-9. This activation and subsequent complement deposition was completely inhibited by the C1q-blocking mAb 2204 and by polyclonal Fab anti-C1q Ab. Evaluation of the LP in the presence of mAb 2204 showed a strong dose-dependent deposition of C4, C3, and C5b-9 using serum from MBL-wildtype (AA) but not MBL-mutant donors (AB or BB genotype), indicating that complement activation under these conditions is MBL-dependent and C1q-independent. Donors with different MBL genotypes were identified using a newly developed oligonucleotide ligation assay (OLA) for detection of MBL exon 1 polymorphisms. We describe a novel functional assay that enables quantification of autologous complement activation via the LP in full human serum up to the formation of the membrane attack complex. This assay offers novel possibilities for patient diagnostics as well as

  11. RNA interference screening of interferon-stimulated genes with antiviral activities against classical swine fever virus using a reporter virus.

    Science.gov (United States)

    Wang, Xiao; Li, Yongfeng; Li, Lian-Feng; Shen, Liang; Zhang, Lingkai; Yu, Jiahui; Luo, Yuzi; Sun, Yuan; Li, Su; Qiu, Hua-Ji

    2016-04-01

    Classical swine fever (CSF) caused by classical swine fever virus (CSFV) is a highly contagious and often fatal disease of pigs, which leads to significant economic losses in many countries. Viral infection can induce the production of interferons (IFNs), giving rise to the transcription of hundreds of IFN-stimulated genes (ISGs) to exert antiviral effects. Although numerous ISGs have been identified to possess antiviral activities against different viruses, rare anti-CSFV ISGs have been reported to date. In this study, to screen anti-CSFV ISGs, twenty-one ISGs reported previously were individually knocked down using small interfering RNAs (siRNAs) followed by infection with a reporter CSFV expressing Renilla luciferase (Rluc). As a result, four novel anti-CSFV ISGs were identified, including natural-resistance-associated macrophage protein 1 (NRAMP1), cytosolic 5'-nucleotidase III A (NT5C3A), chemokine C-X-C motif ligand 10 (CXCL10), and 2'-5'-oligoadenylate synthetase 1 (OAS1), which were further verified to exhibit antiviral activities against wild-type CSFV. We conclude that the reporter virus is a useful tool for efficient screening anti-CSFV ISGs.

  12. The Complement System and Antibody-Mediated Transplant Rejection.

    Science.gov (United States)

    Stites, Erik; Le Quintrec, Moglie; Thurman, Joshua M

    2015-12-15

    Complement activation is an important cause of tissue injury in patients with Ab-mediated rejection (AMR) of transplanted organs. Complement activation triggers a strong inflammatory response, and it also generates tissue-bound and soluble fragments that are clinically useful markers of inflammation. The detection of complement proteins deposited within transplanted tissues has become an indispensible biomarker of AMR, and several assays have recently been developed to measure complement activation by Abs reactive to specific donor HLA expressed within the transplant. Complement inhibitors have entered clinical use and have shown efficacy for the treatment of AMR. New methods of detecting complement activation within transplanted organs will improve our ability to diagnose and monitor AMR, and they will also help guide the use of complement inhibitory drugs.

  13. Viral mimicry of the complement system

    Indian Academy of Sciences (India)

    John Bernet; Jayati Mullick; Akhilesh K Singh; Arvind Sahu

    2003-04-01

    The complement system is a potent innate immune mechanism consisting of cascades of proteins which are designed to fight against and annul intrusion of all the foreign pathogens. Although viruses are smaller in size and have relatively simple structure, they are not immune to complement attack. Thus, activation of the complement system can lead to neutralization of cell-free viruses, phagocytosis of C3b-coated viral particles, lysis of virus-infected cells, and generation of inflammatory and specific immune responses. However, to combat host responses and succeed as pathogens, viruses not only have developed/adopted mechanisms to control complement, but also have turned these interactions to their own advantage. Important examples include poxviruses, herpesviruses, retroviruses, paramyxoviruses and picornaviruses. In this review, we provide information on the various complement evasion strategies that viruses have developed to thwart the complement attack of the host. A special emphasis is given on the interactions between the viral proteins that are involved in molecular mimicry and the complement system.

  14. Complement selectively elicits glutamate release from nerve endings in different regions of mammal central nervous system.

    Science.gov (United States)

    Merega, Elisa; Di Prisco, Silvia; Lanfranco, Massimiliano; Severi, Paolo; Pittaluga, Anna

    2014-05-01

    Our study was aimed at investigating whether complement, a complex of soluble and membrane-associated serum proteins, could, in addition to its well-documented post-synaptic activity, also pre-synaptically affect the release of classic neurotransmitters in central nervous system (CNS). Complement (dilution 1 : 10 to 1 : 10000) elicited the release of preloaded [(3) H]-d-aspartate ([(3) H]d-ASP) and endogenous glutamate from mouse cortical synaptosomes in a dilution-dependent manner. It also evoked [(3) H]d-ASP release from mouse hippocampal, cerebellar, and spinal cord synaptosomes, as well as from rat and human cortical nerve endings, but left unaltered the release of GABA, [(3) H]noradrenaline or [(3) H]acetylcholine. Lowering external Na(+) (from 140 to 40 mM) or Ca(2+) (from 1.2 to 0.1 mM) ions prevented the 1 : 300 complement-evoked [(3) H]d-ASP release from mouse cortical synaptosomes. Complement-induced releasing effect was unaltered in synaptosomes entrapped with the Ca(2+) ions chelator 1,2-bis-(2-aminophenoxy) ethane-N,N,N',N', tetra-acetic acid or with pertussis toxin. Nifedipine,/ω-conotoxin GVIA/ω-conotoxin MVIIC mixture as well as the vesicular ATPase blocker bafilomycin A1 were also inefficacious. The excitatory amino acid transporter blocker DL-threo-ß-benzyloxyaspartic acid, on the contrary, reduced the complement-evoked releasing effect in a concentration-dependent manner. We concluded that complement-induced releasing activity is restricted to glutamatergic nerve endings, where it was accounted for by carrier-mediated release. Our observations afford new insights into the molecular events accounting for immune and CNS crosstalk. We investigated whether complement, a complex of soluble and membrane-associated serum proteins, could pre-synaptically affect the release of classic neurotransmitters in the central nervous system (CNS). Our data provide evidence that complement-induced releasing activity is restricted to glutamatergic nerve endings

  15. Complement and microglia mediate early synapse loss in Alzheimer mouse models.

    Science.gov (United States)

    Hong, Soyon; Beja-Glasser, Victoria F; Nfonoyim, Bianca M; Frouin, Arnaud; Li, Shaomin; Ramakrishnan, Saranya; Merry, Katherine M; Shi, Qiaoqiao; Rosenthal, Arnon; Barres, Ben A; Lemere, Cynthia A; Selkoe, Dennis J; Stevens, Beth

    2016-05-06

    Synapse loss in Alzheimer's disease (AD) correlates with cognitive decline. Involvement of microglia and complement in AD has been attributed to neuroinflammation, prominent late in disease. Here we show in mouse models that complement and microglia mediate synaptic loss early in AD. C1q, the initiating protein of the classical complement cascade, is increased and associated with synapses before overt plaque deposition. Inhibition of C1q, C3, or the microglial complement receptor CR3 reduces the number of phagocytic microglia, as well as the extent of early synapse loss. C1q is necessary for the toxic effects of soluble β-amyloid (Aβ) oligomers on synapses and hippocampal long-term potentiation. Finally, microglia in adult brains engulf synaptic material in a CR3-dependent process when exposed to soluble Aβ oligomers. Together, these findings suggest that the complement-dependent pathway and microglia that prune excess synapses in development are inappropriately activated and mediate synapse loss in AD. Copyright © 2016, American Association for the Advancement of Science.

  16. Targeted complement inhibition and microvasculature in transplants: a therapeutic perspective.

    Science.gov (United States)

    Khan, M A; Hsu, J L; Assiri, A M; Broering, D C

    2016-02-01

    Active complement mediators play a key role in graft-versus-host diseases, but little attention has been given to the angiogenic balance and complement modulation during allograft acceptance. The complement cascade releases the powerful proinflammatory mediators C3a and C5a anaphylatoxins, C3b, C5b opsonins and terminal membrane attack complex into tissues, which are deleterious if unchecked. Blocking complement mediators has been considered to be a promising approach in the modern drug discovery plan, and a significant number of therapeutic alternatives have been developed to dampen complement activation and protect host cells. Numerous immune cells, especially macrophages, develop both anaphylatoxin and opsonin receptors on their cell surface and their binding affects the macrophage phenotype and their angiogenic properties. This review discusses the mechanism that complement contributes to angiogenic injury, and the development of future therapeutic targets by antagonizing activated complement mediators to preserve microvasculature in rejecting the transplanted organ.

  17. Absence of a Classically Activated Macrophage Cytokine Signature in Peripheral Spondylarthritis, Including Psoriatic Arthritis

    NARCIS (Netherlands)

    B. Vandooren; T. Noordenbos; C. Ambarus; S. Krausz; T. Cantaert; N. Yeremenko; M. Boumans; R. Lutter; P.P. Tak; D. Baeten

    2009-01-01

    Objective. Peripheral spondylarthritis (SpA) is characterized by macrophages that express CD163, a marker of alternative activation (M2). The purpose of this study was to assess whether this differential infiltration with macrophage subsets was associated with a different local inflammatory milieu i

  18. Role of complement in neurodegeneration and neuroinflammation.

    Science.gov (United States)

    Bonifati, Domenico Marco; Kishore, Uday

    2007-02-01

    The complement system provides an innate defence mechanism against pathogenic microorganisms. Although viewed for many years as an immune-privileged organ, the central nervous system contains many components of the immune system, including components of the complement system that are synthesized by astrocytes, microglia, and neurons. During the past two decades, a wide range of inflammatory markers, typically absent in the normal elderly population, have been reported in Alzheimer's disease brains. It is becoming evident that sustained brain inflammation might be an essential cofactor in Alzheimer disease and other neurodegenerative disorders such as Parkinson disease, dementia with Lewy bodies, Huntington's and prion diseases. The complement system may be useful in eliminating aggregated and toxic proteins associated with these neurological disorders and thus have a protective effect. However, an exaggerated or insufficient activation of the complement system can have deleterious effect through the activation of microglia, secretion of many proinflammatory cytokines, and generation of oxidative products. The role of complement-mediated inflammation in Alzheimer disease has drawn greater attention recently in view of new therapeutic advances made in the management of the disease. This review is meant to update the role of complement in Alzheimer's disease and other neurodegenerative disorders in view of recent vaccination and immunotherapeutic approaches.

  19. Listening to factually incorrect sentences activates classical language areas and thalamus.

    Science.gov (United States)

    Yu, Tao; Lang, Simone; Birbaumer, Niels; Kotchoubey, Boris

    2011-12-07

    Neurophysiological underpinnings of the integration of information during sentence comprehension have been studied since 1980. However, little is known about integrative processes in sentences containing a word that is semantically congruent, but factually incompatible with the context. In this study, we aimed at investigating the differences between the brain regions involved in responses to factually correct and incorrect sentences. Eighteen healthy volunteers underwent functional MRI while listening passively to 40 correct and 40 incorrect sentences. The contrast between factually correct and incorrect sentence endings revealed large activation areas in the left inferior frontal gyrus, the left middle/superior temporal gyrus, and smaller activations of these areas' homologs in the right hemisphere, in the thalamus, and Brodmann area 6.

  20. Auditory Exostoses, Infracranial Skeleto-Muscular Changes And Maritime Activities In Classical Period Thasos Island

    Science.gov (United States)

    Agelarakis, A.; Serpanos, Y. C.

    Acquired external ear exostoses are an auditory disorder presumably associated with prolonged or repeated exposure to cold aquatic activities. At the ancient necropolis of Thasos, Greece, a low prevalence of auditory exostoses has been documented in one adult male out of an initially larger number of individuals from the ancient necropolis of Thasos, although the city-state was renowned in antiquity for the strength and dependency on its fleet and its seafaring activities in the Aegean and the Black Sea as supported by historical and archaeological records. In addition to auditory exostoses, this individual showed distinct similarities of infracranial axial and appendicular skeletal changes of skeleto-muscular robustness, trauma, and degenerative manifestations to a select sample of 16 males out of 57 individuals interred in proximal contextual associations near the shoreline which may comprise a pattern of occupational conditions when juxtaposed to the context of the larger skeletal population studied at Thasos so far. This study also presents comparative ethnographic information relative to occupational changes documented among a surviving group of wooden boat craftsmen on Thasos, comprising nine male individuals of diverse age-subgroups and intra-trade specializations. It is proposed that the low incidence of external auditory exostoses from ancient Thasos may not necessarily reflect issues of preservation or population sample, but rather the specificity of activities within the domain of specific maritime occupations.

  1. The effects of two forms of physical activity on eyeblink classical conditioning.

    Science.gov (United States)

    Green, John T; Chess, Amy C; Burns, Montana; Schachinger, Kira M; Thanellou, Alexandra

    2011-05-16

    Voluntary exercise, in the form of free access to a running wheel in the home cage, has been shown to improve several forms of learning and memory. Acrobatic training, in the form of learning to traverse an elevated obstacle course, has been shown to induce markers of neural plasticity in the cerebellar cortex in rodents. In three experiments, we examined the effects of these two forms of physical activity on delay eyeblink conditioning in rats. In Experiment 1, exercising rats were given 17 days of free access to a running wheel in their home cage prior to 10 days of delay eyeblink conditioning. Rats that exercised conditioned significantly better and showed a larger reflexive eyeblink unconditioned response to the periocular stimulation unconditioned stimulus than rats that did not exercise. In Experiment 2, exercising rats were given 17 days of free access to a running wheel in their home cage prior to 10 days of explicitly unpaired stimulus presentations. Rats that exercised responded the same to tone, light, and periocular stimulation as rats that did not exercise. In Experiment 3, acrobatic training rats were given 15 days of daily training on an elevated obstacle course prior to 10 days of eyeblink conditioning. Activity control rats underwent 15 days of yoked daily running in an open field. Rats that underwent acrobatic training did not differ in eyeblink conditioning from activity control rats. The ability to measure the learned response precisely, and the well-mapped neural circuitry of eyeblink conditioning offer some advantages for the study of exercise effects on learning and memory.

  2. The Effects of Two Forms of Physical Activity on Eyeblink Classical Conditioning

    Science.gov (United States)

    Green, John T.; Chess, Amy C.; Burns, Montana; Schachinger, Kira M.; Thanellou, Alexandra

    2011-01-01

    Voluntary exercise, in the form of free access to a running wheel in the home cage, has been shown to improve several forms of learning and memory. Acrobatic training, in the form of learning to traverse an elevated obstacle course, has been shown to induce markers of neural plasticity in the cerebellar cortex in rodents. In three experiments, we examined the effects of these two forms of physical activity on delay eyeblink conditioning in rats. In Experiment 1, exercising rats were given 17 days of free access to a running wheel in their home cage prior to 10 days of delay eyeblink conditioning. Rats that exercised conditioned significantly better and showed a larger reflexive eyeblink unconditioned response to the periocular stimulation unconditioned stimulus than rats that did not exercise. In Experiment 2, exercising rats were given 17 days of free access to a running wheel in their home cage prior to 10 days of explicitly unpaired stimulus presentations. Rats that exercised responded the same to tone, light, and periocular stimulation as rats that did not exercise. In Experiment 3, acrobatic training rats were given 15 days of daily training on an elevated obstacle course prior to 10 days of eyeblink conditioning. Activity control rats underwent 15 days of yoked daily running in an open field. Rats that underwent acrobatic training did not differ in eyeblink conditioning from activity control rats. The ability to measure the learned response precisely, and the well-mapped neural circuitry of eyeblink conditioning offer some advantages for the study of exercise effects on learning and memory. PMID:21238502

  3. Classical T Tauri-like Outflow Activity in the Brown Dwarf Mass Regime

    CERN Document Server

    Whelan, E T; Podio, L; Bacciotti, F; Randich, S

    2009-01-01

    Over the last number of years spectroscopic studies have strongly supported the assertion that protostellar accretion and outflow activity persists to the lowest masses. In this paper we present the results of our latest investigation of brown dwarf (BD) outflow activity and report on the discovery of two new outflows. Here ISO-Oph 32 is shown to drive a blue-shifted outflow with a radial velocity of 10-20 km/s and spectro-astrometric analysis constrains the position angle of this outflow to 240 +/- 7 degrees. The BD candidate ISO-Cha1 217 is found to have a bipolar outflow bright in several key forbidden lines (radial velocity = -20 km/s, +40 km/s) and with a PA of 190-210 degrees. A striking feature of the ISO-Cha1 217 outflow is the strong asymmetry between the red and blue-shifted lobes. This asymmetry is revealed in the relative brightness of the two lobes (red-shifted lobe is brighter), the factor of two difference in radial velocity (the red-shifted lobe is faster) and the difference in the electron de...

  4. [Biological roles of complement and recent topics in clinical medicine].

    Science.gov (United States)

    Wakamiya, Nobutaka

    2012-08-01

    The complement has been identified as a