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Sample records for complement inhibitor c4b-binding

  1. Acquisition of complement inhibitor serine protease factor I and its cofactors C4b-binding protein and factor H by Prevotella intermedia.

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    Sven Malm

    Full Text Available Infection with the Gram-negative pathogen Prevotella intermedia gives rise to periodontitis and a growing number of studies implies an association of P. intermedia with rheumatoid arthritis. The serine protease Factor I (FI is the central inhibitor of complement degrading complement components C3b and C4b in the presence of cofactors such as C4b-binding protein (C4BP and Factor H (FH. Yet, the significance of complement inhibitor acquisition in P. intermedia infection and FI binding by Gram-negative pathogens has not been addressed. Here we show that P. intermedia isolates bound purified FI as well as FI directly from heat-inactivated human serum. FI bound to bacteria retained its serine protease activity as shown in degradation experiments with (125I-labeled C4b. Since FI requires cofactors for its activity we also investigated the binding of purified cofactors C4BP and FH and found acquisition of both proteins, which retained their activity in FI mediated degradation of C3b and C4b. We propose that FI binding by P. intermedia represents a new mechanism contributing to complement evasion by a Gram-negative bacterial pathogen associated with chronic diseases.

  2. Human pentraxin 3 binds to the complement regulator c4b-binding protein.

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    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.

  3. Yersinia enterocolitica serum resistance proteins YadA and ail bind the complement regulator C4b-binding protein.

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    Vesa Kirjavainen

    Full Text Available Many pathogens are equipped with factors providing resistance against the bactericidal action of complement. Yersinia enterocolitica, a Gram-negative enteric pathogen with invasive properties, efficiently resists the deleterious action of human complement. The major Y. enterocolitica serum resistance determinants include outer membrane proteins YadA and Ail. Lipopolysaccharide (LPS O-antigen (O-ag and outer core (OC do not contribute directly to complement resistance. The aim of this study was to analyze a possible mechanism whereby Y. enterocolitica could inhibit the antibody-mediated classical pathway of complement activation. We show that Y. enterocolitica serotypes O:3, O:8, and O:9 bind C4b-binding protein (C4bp, an inhibitor of both the classical and lectin pathways of complement. To identify the C4bp receptors on Y. enterocolitica serotype O:3 surface, a set of mutants expressing YadA, Ail, O-ag, and OC in different combinations was tested for the ability to bind C4bp. The studies showed that both YadA and Ail acted as C4bp receptors. Ail-mediated C4bp binding, however, was blocked by the O-ag and OC, and could be observed only with mutants lacking these LPS structures. C4bp bound to Y. enterocolitica was functionally active and participated in the factor I-mediated degradation of C4b. These findings show that Y. enterocolitica uses two proteins, YadA and Ail, to bind C4bp. Binding of C4bp could help Y. enterocolitica to evade complement-mediated clearance in the human host.

  4. C4b binding protein binds to CD154 preventing CD40 mediated cholangiocyte apoptosis: a novel link between complement and epithelial cell survival.

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    Kevin T Williams

    Full Text Available Activation of CD40 on hepatocytes and cholangiocytes is critical for amplifying Fas-mediated apoptosis in the human liver. C4b-Binding Protein (C4BP has been reported to act as a potential surrogate ligand for CD40, suggesting that it could be involved in modulating liver epithelial cell survival. Using surface plasmon resonance (BiaCore analysis supported by gel filtration we have shown that C4BP does not bind CD40, but it forms stable high molecular weight complexes with soluble CD40 ligand (sCD154. These C4BP/sCD154 complexes bound efficiently to immobilised CD40, but when applied to cholangiocytes they failed to induce apoptosis or proliferation or to activate NFkB, AP-1 or STAT 3, which are activated by sCD154 alone. Thus C4BP can modulate CD40/sCD154 interactions by presenting a high molecular weight multimeric sCD154/C4BP complex that suppresses critical intracellular signalling pathways, permitting cell survival without inducing proliferation. Immunohistochemistry demonstrated co-localisation and enhanced expression of C4BP and CD40 in human liver cancers. These findings suggest a novel pathway whereby components of the complement system and TNF ligands and receptors might be involved in modulating epithelial cell survival in chronic inflammation and malignant disease.

  5. Hepatitis B virus X protein up-regulates C4b-binding protein α through activating transcription factor Sp1 in protection of hepatoma cells from complement attack.

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    Feng, Guoxing; Li, Jiong; Zheng, Minying; Yang, Zhe; Liu, Yunxia; Zhang, Shuqin; Ye, Lihong; Zhang, Weiying; Zhang, Xiaodong

    2016-05-10

    Hepatitis B virus X protein (HBx) plays crucial roles in the development of hepatocellular carcinoma (HCC). We previously showed that HBx protected hepatoma cells from complement attack by activation of CD59. Moreover, in this study we found that HBx protected hepatoma cells from complement attack by activation of C4b-binding protein α (C4BPα), a potent inhibitor of complement system. We observed that HBx were positively correlated with those of C4BPα in clinical HCC tissues. Mechanistically, HBx activated the promoter core region of C4BPα, located at -1199/-803nt, through binding to transcription factor Sp1. In addition, chromatin immunoprecipitation (ChIP) assays showed that HBx was able to bind to the promoter of C4BPα, which could be blocked by Sp1 silencing. Functionally, knockdown of C4BPα obviously increased the deposition of C5b-9, a complex of complement membrane attack, and remarkably abolished the HBx-induced resistance of hepatoma cells from complement attack in vitro and in vivo. Thus, we conclude that HBx up-regulates C4BPα through activating transcription factor Sp1 in protection of liver cancer cells from complement attack. Our finding provides new insights into the mechanism by which HBx enhances protection of hepatoma cells from complement attack.

  6. C4BPAL1, a member of the human regulator of complement activation (RCA) gene cluster that resulted from the duplication of the gene coding for the [alpha]-chain of C4b-binding protein

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    Sanchez-Corral, P.; Pardo-Manuel de Villena, F.; Rey-Campos, J.; Rodriguez de Cordoba, S. (Unidad de Immunologia, Madrid (Spain))

    1993-07-01

    The regulator of complement activation (RCA) gene cluster evolved by multiple gene duplications to produce a family of genes coding for proteins that collectively control the activation of the complement system. The authors report here the characterization of C4BPAL1, a member of the human RCA gene cluster that arose from the duplication of the C4BPA gene after the separation of rodent and primate lineages. C4BPAL1 maps 20 kb downstream of the C4BPA gene and is in the same 5[prime] to 3[prime] orientation found for all RCA genes characterized thus far. It includes nine exon-like regions homologous to exons 2-8, 11, and 12 of the C4BPA gene. Analysis of the C4BPAL1 sequence suggests that it is currently a pseudogene in humans. However, comparisons between C4BPAL1 and the human and murine C4BPA genes show sequence conservation, which strongly suggests that, for a long period of time, C4BPAL1 has been a functional gene coding for a protein with structural requirements similar to those of the [alpha]-chain of C4b-binding protein. 50 refs., 5 figs., 1 tab.

  7. Synergistic inhibition of the intrinsic factor X activation by protein S and C4b-binding protein

    NARCIS (Netherlands)

    Koppelman, S.J.

    1995-01-01

    The complement protein C4b-binding protein plays an important role in the regulation of the protein C anticoagulant pathway. C4b-binding protein can bind to protein S, thereby inhibiting the cofactor activity of protein S for activated protein C. In this report, we describe a new role for

  8. The superfamily of C3b/C4b-binding proteins

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    Kristensen, Torsten; D'Eustachio, P; Ogata, R T

    1987-01-01

    The determination of primary structures by amino acid and nucleotide sequencing for the C3b-and/or C4b-binding proteins H, C4BP, CR1, B, and C2 has revealed the presence of a common structural element. This element is approximately 60 amino acids long and is repeated in a tandem fashion, commencing...... at the amino-terminal end of each molecule. Two other complement components, C1r and C1s, have two of these repeating units in the carboxy-terminal region of their noncatalytic A chains. Three noncomplement proteins, beta 2-glycoprotein I (beta 2I), the interleukin 2 receptor (IL 2 receptor), and the b chain...... of factor XIII, have 4, 2 and 10 of these repeating units, respectively. These proteins obviously belong to the above family, although there is no evidence that they interact with C3b and/or C4b. Human haptoglobin and rat leukocyte common antigen also contain two and three repeating units, respectively...

  9. C4b-binding protein is present in affected areas of myocardial infarction during the acute inflammatory phase and covers a larger area than C3.

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    Leendert A Trouw

    Full Text Available BACKGROUND: During myocardial infarction reduced blood flow in the heart muscle results in cell death. These dying/dead cells have been reported to bind several plasma proteins such as IgM and C-reactive protein (CRP. In the present study we investigated whether fluid-phase complement inhibitor C4b-binding protein (C4BP would also bind to the infarcted heart tissue. METHODS AND FINDINGS: Initial studies using immunohistochemistry on tissue arrays for several cardiovascular disorders indicated that C4BP can be found in heart tissue in several cardiac diseases but that it is most abundantly found in acute myocardial infarction (AMI. This condition was studied in more detail by analyzing the time window and extent of C4BP positivity. The binding of C4BP correlates to the same locations as C3b, a marker known to correlate to the patterns of IgM and CRP staining. Based on criteria that describe the time after infarction we were able to pinpoint that C4BP binding is a relatively early marker of tissue damage in myocardial infarction with a peak of binding between 12 hours and 5 days subsequent to AMI, the phase in which infiltration of neutrophilic granulocytes in the heart is the most extensive. CONCLUSIONS: C4BP, an important fluid-phase inhibitor of the classical and lectin pathway of complement activation binds to jeopardized cardiomyocytes early after AMI and co-localizes to other well known markers such as C3b.

  10. Complement activation and inhibition: a delicate balance

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

    2009-01-01

    proteins, pentraxins, amyloid deposits, prions and DNA, all bind the complement activator C1q, but also interact with complement inhibitors C4b-binding protein and factor H. This contrasts to the interaction between C1q and immune complexes, in which case no inhibitors bind, resulting in full complement...

  11. Conserved patterns hidden within group A Streptococcus M protein hypervariability recognize human C4b-binding protein.

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    Buffalo, Cosmo Z; Bahn-Suh, Adrian J; Hirakis, Sophia P; Biswas, Tapan; Amaro, Rommie E; Nizet, Victor; Ghosh, Partho

    2016-09-05

    No vaccine exists against group A Streptococcus (GAS), a leading cause of worldwide morbidity and mortality. A severe hurdle is the hypervariability of its major antigen, the M protein, with >200 different M types known. Neutralizing antibodies typically recognize M protein hypervariable regions (HVRs) and confer narrow protection. In stark contrast, human C4b-binding protein (C4BP), which is recruited to the GAS surface to block phagocytic killing, interacts with a remarkably large number of M protein HVRs (apparently ∼90%). Such broad recognition is rare, and we discovered a unique mechanism for this through the structure determination of four sequence-diverse M proteins in complexes with C4BP. The structures revealed a uniform and tolerant 'reading head' in C4BP, which detected conserved sequence patterns hidden within hypervariability. Our results open up possibilities for rational therapies that target the M-C4BP interaction, and also inform a path towards vaccine design.

  12. Conserved patterns hidden within group A Streptococcus M protein hypervariability recognize human C4b-binding protein

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    Buffalo, Cosmo Z.; Bahn-Suh, Adrian J.; Hirakis, Sophia P.; Biswas, Tapan; Amaro, Rommie E.; Nizet, Victor; Ghosh, Partho

    2016-09-05

    No vaccine exists against group A Streptococcus (GAS), a leading cause of worldwide morbidity and mortality. A severe hurdle is the hypervariability of its major antigen, the M protein, with >200 different M types known. Neutralizing antibodies typically recognize M protein hypervariable regions (HVRs) and confer narrow protection. In stark contrast, human C4b-binding protein (C4BP), which is recruited to the GAS surface to block phagocytic killing, interacts with a remarkably large number of M protein HVRs (apparently ~90%). Such broad recognition is rare, and we discovered a unique mechanism for this through the structure determination of four sequence-diverse M proteins in complexes with C4BP. The structures revealed a uniform and tolerant ‘reading head’ in C4BP, which detected conserved sequence patterns hidden within hypervariability. Our results open up possibilities for rational therapies that target the M–C4BP interaction, and also inform a path towards vaccine design.

  13. Epididymal C4b-binding protein is processed and degraded during transit through the duct and is not essential for fertility

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    Nonaka, Mayumi I.; Zsigmond, Eva; Kudo, Akihiko; Kawakami, Hayato; Yoshida, Kaoru; Yoshida, Manabu; Kawano, Natsuko; Miyado, Kenji; Nonaka, Masaru; Wetsel, Rick A.

    2014-01-01

    C4b-binding protein (C4BP) is known as one of the circulating complement regulators that prevents excessive activation of the host-defense complement system. We have reported previously that C4BP is expressed abundantly in the rodent epididymis, one of the male reproductive organs connecting the testis and vas deferens, where immature spermatozoa acquire their motility and fertilizing ability during their transit through the duct. Epididymal C4BP (EpC4BP) is synthesized androgen-dependently by the epithelial cells, secreted into the lumen, and bound to the outer membrane of the passing spermatozoa. In this study, we found that EpC4BP is secreted as a large oligomer, similar to the serum C4BP, but is digested during the epididymal transit and is almost lost from both the luminal fluid and the sperm surface in the vas deferens. Such a processing pattern is not known in serum C4BP, suggesting that EpC4BP and serum C4BP might have different functional mechanisms, and that there is a novel function of EpC4BP in reproduction. In addition, the disappearance of EpC4BP from the sperm surface prior to ejaculation suggests that EpC4BP works only in the epididymis and would not work in the female reproductive tract to protect spermatozoa from complement attack. Next, we generated C4BP-deficient (C4BP−/−) mice to examine the possible role of EpC4BP in reproduction. However, the C4BP−/− mice were fertile and no significant differences were observed between the C4BP−/− and wild-type mouse spermatozoa in terms of morphology, motility, and rate of the spontaneous acrosome reaction. These results suggest that EpC4BP is involved in male reproduction, but not essential for sperm maturation. PMID:25468721

  14. Conserved patterns hidden within group A Streptococcus M protein hypervariability are responsible for recognition of human C4b-binding protein

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    Buffalo, Cosmo Z.; Bahn-Suh, Adrian J.; Sophia P Hirakis; Biswas, Tapan; Amaro, Rommie E.; Nizet, Victor; Ghosh, Partho

    2016-01-01

    No vaccine exists against group A Streptococcus (GAS), a leading cause of worldwide morbidity and mortality. A severe hurdle is the hypervariability of its major antigen, the M protein, with >200 different M types known. Neutralizing antibodies typically recognize M protein hypervariable regions (HVRs) and confer narrow protection. In stark contrast, human C4b-binding protein (C4BP), which is recruited to the GAS surface to block phagocytic killing, interacts with a remarkably large number of...

  15. Conserved patterns hidden within group A Streptococcus M protein hypervariability are responsible for recognition of human C4b-binding protein

    Science.gov (United States)

    Buffalo, Cosmo Z.; Bahn-Suh, Adrian J.; Hirakis, Sophia P.; Biswas, Tapan; Amaro, Rommie E.; Nizet, Victor; Ghosh, Partho

    2016-01-01

    No vaccine exists against group A Streptococcus (GAS), a leading cause of worldwide morbidity and mortality. A severe hurdle is the hypervariability of its major antigen, the M protein, with >200 different M types known. Neutralizing antibodies typically recognize M protein hypervariable regions (HVRs) and confer narrow protection. In stark contrast, human C4b-binding protein (C4BP), which is recruited to the GAS surface to block phagocytic killing, interacts with a remarkably large number of M protein HVRs (apparently ~90%). Such broad recognition is rare, and we discovered a unique mechanism for this through structure determination of four sequence-diverse M proteins in complex with C4BP. The structures revealed a uniform and tolerant ‘reading head’ in C4BP, which detected conserved sequence patterns hidden within hypervariability. Our results open up possibilities for rational therapies targeting the M-C4BP interaction, and also inform a path towards vaccine design. PMID:27595425

  16. C4b-binding protein inhibits the factor V-dependent but not the factor V-independent cofactor activity of protein S in the activated protein C-mediated inactivation of factor VIIIa

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    van de Poel, R. H.; Meijers, J. C.; Bouma, B. N.

    2001-01-01

    Activated protein C (APC) is an important inactivator of coagulation factors Va and VIIIa. In the inactivation of factors Va and VIIIa, protein S serves as a cofactor to APC. Protein S can bind to C4b-binding protein (C4BP), and thereby loses its cofactor activity to APC. By modulating free protein

  17. T cell responses induced by adenoviral vectored vaccines can be adjuvanted by fusion of antigen to the oligomerization domain of C4b-binding protein.

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    Emily K Forbes

    Full Text Available Viral vectored vaccines have been shown to induce both T cell and antibody responses in animals and humans. However, the induction of even higher level T cell responses may be crucial in achieving vaccine efficacy against difficult disease targets, especially in humans. Here we investigate the oligomerization domain of the α-chain of C4b-binding protein (C4 bp as a candidate T cell "molecular adjuvant" when fused to malaria antigens expressed by human adenovirus serotype 5 (AdHu5 vectored vaccines in BALB/c mice. We demonstrate that i C-terminal fusion of an oligomerization domain can enhance the quantity of antigen-specific CD4(+ and CD8(+ T cell responses induced in mice after only a single immunization of recombinant AdHu5, and that the T cells maintain similar functional cytokine profiles; ii an adjuvant effect is observed for AdHu5 vectors expressing either the 42 kDa C-terminal domain of Plasmodium yoelii merozoite surface protein 1 (PyMSP1(42 or the 83 kDa ectodomain of P. falciparum strain 3D7 apical membrane antigen 1 (PfAMA1, but not a candidate 128kDa P. falciparum MSP1 biallelic fusion antigen; iii following two homologous immunizations of AdHu5 vaccines, antigen-specific T cell responses are further enhanced, however, in both BALB/c mice and New Zealand White rabbits no enhancement of functional antibody responses is observed; and iv that the T cell adjuvant activity of C4 bp is not dependent on a functional Fc-receptor γ-chain in the host, but is associated with the oligomerization of small (<80 kDa antigens expressed by recombinant AdHu5. The oligomerization domain of C4 bp can thus adjuvant T cell responses induced by AdHu5 vectors against selected antigens and its clinical utility as well as mechanism of action warrant further investigation.

  18. 21 CFR 866.5250 - Complement C2 inhibitor (inactivator) immunological test system.

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    2010-04-01

    ... Test Systems § 866.5250 Complement C2 inhibitor (inactivator) immunological test system. (a) Identification. A complement C1 inhibitor (inactivator) immunological test system is a device that consists of... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Complement C2 inhibitor (inactivator...

  19. Complement inhibitors for age-related macular degeneration.

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    Williams, Michael A; McKay, Gareth J; Chakravarthy, Usha

    2014-01-15

    Given the relatively high prevalence of age-related macular degeneration (AMD) and the increased incidence of AMD as populations age, the results of trials of novel treatments are awaited with much anticipation. The complement cascade describes a series of proteolytic reactions occurring throughout the body that generate proteins with a variety of roles including the initiation and promotion of immune reactions against foreign materials or micro-organisms. The complement cascade is normally tightly regulated, but much evidence implicates complement overactivity in AMD and so it is a logical therapeutic target in the treatment of AMD. To assess the effects and safety of complement inhibitors in the prevention or treatment of advanced AMD. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 11), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to November 2013), EMBASE (January 1980 to November 2013), Allied and Complementary Medicine Database (AMED) (January 1985 to November 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to November 2013), OpenGrey (System for Information on Grey Literature in Europe) (www.opengrey.eu/), Web of Science Conference Proceedings Citation Index - Science (CPCI-S) (January 1990 to November 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 21 November 2013. We also performed handsearching of proceedings, from 2012 onwards, of meetings and conferences of specific professional organisations. We planned to include randomised controlled trials (RCTs) with

  20. Complement

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    ... in the liquid portion of your blood. The complement system is a group of proteins that move freely ... a role in the development of inflammation. The complement system protects the body from infections, dead cells and ...

  1. Viral-derived complement inhibitors: current status and potential role in immunomodulation

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    Zaraket, Hassan

    2016-01-01

    The complement system is one of the body’s major innate immune defense mechanisms in vertebrates. Its function is to detect foreign bodies and promote their elimination through opsonisation or lysis. Complement proteins play an important role in the immunopathogenesis of several disorders. However, excessive complement activation does not confer more protection but instead leads to several autoimmune and inflammatory diseases. With inappropriate activation of the complement system, activated complement proteins and glycoproteins may damage both healthy and diseased tissues. Development of complement inhibitors represents an effective approach in controlling dysregulated complement activity and reducing disease severity, yet few studies have investigated the nature and role of novel complement inhibitory proteins of viral origin. Viral complement inhibitors have important implications in understanding the importance of complement inhibition and their role as a promising novel therapeutic approach in diseases caused by dysregulated complement function. In this review, we discuss the role and importance of complement inhibitors derived from several viruses in the scope of human inflammatory and autoimmune diseases. PMID:27798122

  2. Complement system proteins which interact with C3b or C4b A superfamily of structurally related proteins

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    Reid, K B M; Bentley, D R; Campbell, R D

    1986-01-01

    Recent cDNA sequencing data has allowed the prediction of the entire amino acid sequences of complement components factor B and C2, the complement control proteins factor H and C4b-binding protein and a partial sequence for the Cab/C4b receptor CR1. These proteins all contain internal repeating u...

  3. Complement inhibitors to treat IgM-mediated autoimmune hemolysis

    NARCIS (Netherlands)

    Wouters, Diana; Zeerleder, Sacha

    2015-01-01

    Complement activation in autoimmune hemolytic anemia may exacerbate extravascular hemolysis and may occasionally result in intravascular hemolysis. IgM autoantibodies as characteristically found in cold autoantibody autoimmune hemolytic anemia, in cold agglutinin disease but also in a considerable

  4. How Escherichia coli Circumvent Complement-Mediated Killing

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    Angela S. Barbosa

    2017-04-01

    Full Text Available Complement is a crucial arm of the innate immune response against invading bacterial pathogens, and one of its main functions is to recognize and destroy target cells. Similar to other pathogens, Escherichia coli has evolved mechanisms to overcome complement activation. It is well known that capsular polysaccharide may confer resistance to complement-mediated killing and phagocytosis, being one of the strategies adopted by this bacterium to survive in serum. In addition, proteases produced by E. coli have been shown to downregulate the complement system. Pic, an autotransporter secreted by different pathogens in the Enterobacteriaceae family, is able to cleave C2, C3/C3b, and C4/C4b and works synergistically with human Factor I and Factor H (FH, thereby promoting inactivation of C3b. Extracellular serine protease P, a serine protease of enterohemorrhagic E. coli (EHEC, downregulates complement activation by cleaving C3/C3b and C5. StcE, a metalloprotease secreted by EHEC, inhibits the classical complement-mediated cell lysis by potentiating the action of C1 inhibitor, and the periplasmic protease Prc contributes to E. coli complement evasion by interfering with the classical pathway activation and by preventing membrane attack complex deposition. Finally, it has been described that E. coli proteins interact with negative complement regulators to modulate complement activation. The functional consequences resulting from the interaction of outer membrane protein A, new lipoprotein I, outer membrane protein W, and Stx2 with proteins of the FH family and C4b-binding protein (C4BP are discussed in detail. In brief, in this review, we focused on the different mechanisms used by pathogenic E. coli to circumvent complement attack, allowing these bacteria to promote a successful infection.

  5. Microbes bind complement inhibitor factor H via a common site.

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    T Meri

    Full Text Available To cause infections microbes need to evade host defense systems, one of these being the evolutionarily old and important arm of innate immunity, the alternative pathway of complement. It can attack all kinds of targets and is tightly controlled in plasma and on host cells by plasma complement regulator factor H (FH. FH binds simultaneously to host cell surface structures such as heparin or glycosaminoglycans via domain 20 and to the main complement opsonin C3b via domain 19. Many pathogenic microbes protect themselves from complement by recruiting host FH. We analyzed how and why different microbes bind FH via domains 19-20 (FH19-20. We used a selection of FH19-20 point mutants to reveal the binding sites of several microbial proteins and whole microbes (Haemophilus influenzae, Bordetella pertussis, Pseudomonas aeruginosa, Streptococcus pneumonia, Candida albicans, Borrelia burgdorferi, and Borrelia hermsii. We show that all studied microbes use the same binding region located on one side of domain 20. Binding of FH to the microbial proteins was inhibited with heparin showing that the common microbial binding site overlaps with the heparin site needed for efficient binding of FH to host cells. Surprisingly, the microbial proteins enhanced binding of FH19-20 to C3b and down-regulation of complement activation. We show that this is caused by formation of a tripartite complex between the microbial protein, FH, and C3b. In this study we reveal that seven microbes representing different phyla utilize a common binding site on the domain 20 of FH for complement evasion. Binding via this site not only mimics the glycosaminoglycans of the host cells, but also enhances function of FH on the microbial surfaces via the novel mechanism of tripartite complex formation. This is a unique example of convergent evolution resulting in enhanced immune evasion of important pathogens via utilization of a "superevasion site."

  6. 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; Mendes-Sousa, Antonio Ferreira; Coutinho-Abreu, Iliano V; Rasouli, Manoochehr; Brandt, Elizabeth A; Meneses, Claudio; Lima, Kolyvan Ferreira; Nascimento Araújo, Ricardo; Pereira, Marcos Horácio; Kotsyfakis, Michalis; Oliveira, Fabiano; Kamhawi, Shaden; Ribeiro, Jose M C; Gontijo, Nelder F; Collin, Nicolas; Valenzuela, Jesus G

    2016-01-13

    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.

  7. Identification of C3b-Binding Small-Molecule Complement Inhibitors Using Cheminformatics.

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    Garcia, Brandon L; Skaff, D Andrew; Chatterjee, Arindam; Hanning, Anders; Walker, John K; Wyckoff, Gerald J; Geisbrecht, Brian V

    2017-05-01

    The complement system is an elegantly regulated biochemical cascade formed by the collective molecular recognition properties and proteolytic activities of more than two dozen membrane-bound or serum proteins. Complement plays diverse roles in human physiology, such as acting as a sentry against invading microorganisms, priming of the adaptive immune response, and removal of immune complexes. However, dysregulation of complement can serve as a trigger for a wide range of human diseases, which include autoimmune, inflammatory, and degenerative conditions. Despite several potential advantages of modulating complement with small-molecule inhibitors, small-molecule drugs are highly underrepresented in the current complement-directed therapeutics pipeline. In this study, we have employed a cheminformatics drug discovery approach based on the extensive structural and functional knowledge available for the central proteolytic fragment of the cascade, C3b. Using parallel in silico screening methodologies, we identified 45 small molecules that putatively bind C3b near ligand-guided functional hot spots. Surface plasmon resonance experiments resulted in the validation of seven dose-dependent C3b-binding compounds. Competition-based biochemical assays demonstrated the ability of several C3b-binding compounds to interfere with binding of the original C3b ligand that guided their discovery. In vitro assays of complement function identified a single complement inhibitory compound, termed cmp-5, and mechanistic studies of the cmp-5 inhibitory mode revealed it acts at the level of C5 activation. This study has led to the identification of a promising new class of C3b-binding small-molecule complement inhibitors and, to our knowledge, provides the first demonstration of cheminformatics-based, complement-directed drug discovery. Copyright © 2017 by The American Association of Immunologists, Inc.

  8. An Ixodes ricinus Tick Salivary Lectin Pathway Inhibitor Protects Borrelia burgdorferi sensu lato from Human Complement

    NARCIS (Netherlands)

    Wagemakers, Alex; Coumou, Jeroen; Schuijt, Tim J.; Oei, Anneke; Nijhof, Ard M.; van 't Veer, Cornelis; van der Poll, Tom; Bins, Adriaan D.; Hovius, Joppe W. R.

    2016-01-01

    We previously identified tick salivary lectin pathway inhibitor (TSLPI) in Ixodes scapularis, a vector for Borrelia burgdorferi sensu stricto (s.s.) in North America. TSLPI is a salivary protein facilitating B. burgdorferi s.s. transmission and acquisition by inhibiting the host lectin complement

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

    Science.gov (United States)

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

    2001-02-01

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

  10. An Ixodes ricinus Tick Salivary Lectin Pathway Inhibitor Protects Borrelia burgdorferi sensu lato from Human Complement.

    Science.gov (United States)

    Wagemakers, Alex; Coumou, Jeroen; Schuijt, Tim J; Oei, Anneke; Nijhof, Ard M; van 't Veer, Cornelis; van der Poll, Tom; Bins, Adriaan D; Hovius, Joppe W R

    2016-04-01

    We previously identified tick salivary lectin pathway inhibitor (TSLPI) in Ixodes scapularis, a vector for Borrelia burgdorferi sensu stricto (s.s.) in North America. TSLPI is a salivary protein facilitating B. burgdorferi s.s. transmission and acquisition by inhibiting the host lectin complement pathway through interference with mannose binding lectin (MBL) activity. Since Ixodes ricinus is the predominant vector for Lyme borreliosis in Europe and transmits several complement sensitive B. burgdorferi sensu lato (s.l.) strains, we aimed to identify, describe, and characterize the I. ricinus ortholog of TSLPI. We performed (q)PCRs on I. ricinus salivary gland cDNA to identify a TSLPI ortholog. Next, we generated recombinant (r)TSLPI in a Drosophila expression system and examined inhibition of the MBL complement pathway and complement-mediated killing of B. burgdorferi s.l. in vitro. We identified a TSLPI ortholog in I. ricinus salivary glands with 93% homology at the RNA and 89% at the protein level compared to I. scapularis TSLPI, which was upregulated during tick feeding. In silico analysis revealed that TSLPI appears to be part of a larger family of Ixodes salivary proteins among which I. persulcatus basic tail salivary proteins and I. scapularis TSLPI and Salp14. I. ricinus rTSLPI inhibited the MBL complement pathway and protected B. burgdorferi s.s. and Borrelia garinii from complement-mediated killing. We have identified a TSLPI ortholog, which protects B. burgdorferi s.l. from complement-mediated killing in I. ricinus, the major vector for tick-borne diseases in Europe.

  11. Scabies mite inactive serine proteases are potent inhibitors of the human complement lectin pathway.

    Directory of Open Access Journals (Sweden)

    Simone L Reynolds

    2014-05-01

    Full Text Available Scabies is an infectious skin disease caused by the mite Sarcoptes scabiei and has been classified as one of the six most prevalent epidermal parasitic skin diseases infecting populations living in poverty by the World Health Organisation. The role of the complement system, a pivotal component of human innate immunity, as an important defence against invading pathogens has been well documented and many parasites have an arsenal of anti-complement defences. We previously reported on a family of scabies mite proteolytically inactive serine protease paralogues (SMIPP-Ss thought to be implicated in host defence evasion. We have since shown that two family members, SMIPP-S D1 and I1 have the ability to bind the human complement components C1q, mannose binding lectin (MBL and properdin and are capable of inhibiting all three human complement pathways. This investigation focused on inhibition of the lectin pathway of complement activation as it is likely to be the primary pathway affecting scabies mites. Activation of the lectin pathway relies on the activation of MBL, and as SMIPP-S D1 and I1 have previously been shown to bind MBL, the nature of this interaction was examined using binding and mutagenesis studies. SMIPP-S D1 bound MBL in complex with MBL-associated serine proteases (MASPs and released the MASP-2 enzyme from the complex. SMIPP-S I1 was also able to bind MBL in complex with MASPs, but MASP-1 and MASP-2 remained in the complex. Despite these differences in mechanism, both molecules inhibited activation of complement components downstream of MBL. Mutagenesis studies revealed that both SMIPP-Ss used an alternative site of the molecule from the residual active site region to inhibit the lectin pathway. We propose that SMIPP-Ss are potent lectin pathway inhibitors and that this mechanism represents an important tool in the immune evasion repertoire of the parasitic mite and a potential target for therapeutics.

  12. Both Freshly Prepared and Frozen-Stored Amniotic Membrane Cells Express the Complement Inhibitor CD59

    Directory of Open Access Journals (Sweden)

    Ágnes Füst

    2012-01-01

    Full Text Available Amniotic membrane proved to be very effective tool in the treatment of a number of ocular surface diseases. The amniotic membrane, however, has to be stored before its transplantation onto the ocular surface followed by mandatory serologic control in order to exclude the transmission of certain viruses. Therefore it is most important to study if cryopreservation of the membrane affects cell surface expression of the molecules. We measured cell surface expression of CD59, a membrane-bound complement inhibitor on the cells of freshly prepared and cryopreserved amniotic membrane. Cells of amniotic membrane were separated mechanically. Epithelial and mesenchymal cells were identified by the intracellular expression of nanog and the cell surface ICAM1 positivity, respectively. Multicolor flow cytometric immunophenotyping was used for determination of the CD59 expression. CellQuest-Pro software program (Becton Dickinson was used both for measurements and analysis. CD59-positive cells could be detected in all investigated samples and in all investigated cell types, although the expression level of CD59 differed. CD59 was expressed both on freshly prepared and frozen-stored samples. Higher level of CD59 was detected on ICAM1+ mesenchymal cells than on nanog+ epithelial cells. Our findings indicate that amniotic membranes maintain their complement inhibiting capacity after cryopreservation.

  13. Peptide Inhibitor of Complement C1 Inhibits the Peroxidase Activity of Hemoglobin and Myoglobin

    Directory of Open Access Journals (Sweden)

    Pamela S. Hair

    2017-01-01

    Full Text Available Hemoglobin is the natural carrier of oxygen in red blood cells (RBCs. While intracellular hemoglobin provides life-sustaining oxygen transport, extracellular free hemoglobin displays toxicity due to inherent peroxidase activity generating reactive oxygen species that subsequently react with the hemoglobin molecule to produce toxic heme degradation products resulting in free radicals, oxidative stress damage, and lipid peroxidation. We have recently demonstrated that Peptide Inhibitor of Complement C1 (PIC1 inhibits peroxidase activity of the heme-based enzyme myeloperoxidase. To elucidate whether PIC1 could inhibit peroxidase activity of hemoglobin, we evaluated the consequence of PIC1 on RBC lysates, methemoglobin, and myoglobin using tetramethylbenzidine (TMB as an oxidation target. PIC1 reversibly and dose-dependently prevented TMB oxidation to tetramethylbenzidine diimine by RBC lysates, methemoglobin, and myoglobin, having comparable activity to the inhibitor 4-aminobenzoic acid hydrazide. PIC1 inhibited TMB oxidation of RBC lysates similar to L-cysteine suggesting that the two cysteine residues contained in PIC1 may mediate peroxidase activity. PIC1 also inhibited heme destruction by NaOCl for RBC lysates, hemoglobin, and myoglobin as assayed by preservation of the Soret absorbance peak in the presence of NaOCl and reduction in free iron release. In conclusion, PIC1 inhibits peroxidase activity of hemoglobin and myoglobin likely via an antioxidant mechanism.

  14. The Staphylococcus aureus protein Sbi acts as a complement inhibitor and forms a tripartite complex with host complement Factor H and C3b.

    Directory of Open Access Journals (Sweden)

    Katrin Haupt

    2008-12-01

    Full Text Available The Gram-positive bacterium Staphylococcus aureus, similar to other pathogens, binds human complement regulators Factor H and Factor H related protein 1 (FHR-1 from human serum. Here we identify the secreted protein Sbi (Staphylococcus aureus binder of IgG as a ligand that interacts with Factor H by a-to our knowledge-new type of interaction. Factor H binds to Sbi in combination with C3b or C3d, and forms tripartite SbiratioC3ratioFactor H complexes. Apparently, the type of C3 influences the stability of the complex; surface plasmon resonance studies revealed a higher stability of C3d complexed to Sbi, as compared to C3b or C3. As part of this tripartite complex, Factor H is functionally active and displays complement regulatory activity. Sbi, by recruiting Factor H and C3b, acts as a potent complement inhibitor, and inhibits alternative pathway-mediated lyses of rabbit erythrocytes by human serum and sera of other species. Thus, Sbi is a multifunctional bacterial protein, which binds host complement components Factor H and C3 as well as IgG and beta(2-glycoprotein I and interferes with innate immune recognition.

  15. Regulation of complement membrane attack complex formation in myocardial infarction.

    OpenAIRE

    Väkevä, A.; Laurila, P; Meri, S.

    1993-01-01

    Recent studies have suggested that the complement (C) system is involved in the development of tissue injury of myocardial infarction. As it is not known why the strictly controlled C system starts to react against autologous heart tissue, we have analyzed the expression of various membrane regulators of C (CR1, DAF, MCP, CD59, C8 binding protein) and the pattern of deposition of C components and plasma C regulators (C4b binding protein and vitronectin) in normal (n = 7) and infarcted (n = 13...

  16. 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.

  17. Dynamic monitoring of p53 translocation to mitochondria for the analysis of specific inhibitors using luciferase-fragment complementation.

    Science.gov (United States)

    Noda, Natsumi; Awais, Raheela; Sutton, Robert; Awais, Muhammad; Ozawa, Takeaki

    2017-12-01

    Intracellular protein translocation plays a pivotal role in regulating complex biological processes, including cell death. The tumor suppressor p53 is a transcription factor activated by DNA damage and oxidative stress that also translocates from the cytosol into the mitochondrial matrix to facilitate necrotic cell death. However, specific inhibitors of p53 mitochondrial translocation are largely unknown. To explore the inhibitors of p53, we developed a bioluminescent probe to monitor p53 translocation from cytosol to mitochondria using luciferase fragment complementation assays. The probe is composed of a novel pair of luciferase fragments, the N-terminus of green click beetle luciferase CBG68 (CBGN) and multiple-complement luciferase fragment (McLuc1). The combination of luciferase fragments showed significant luminescence intensity and high signal-to-background ratio. When the p53 connected with McLuc1 translocates from cytosol into mitochondrial matrix, CBGN in mitochondrial matrix enables to complement with McLuc1, resulting in the restoration of the luminescence. The luminescence intensity was significantly increased under hydrogen peroxide-induced oxidative stress following the complementation of CBGN and McLuc1. Pifithrin-μ, a selective inhibitor of p53 mitochondrial translocation, prevented the mitochondrial translocation of the p53 probe in a concentration-dependent manner. Furthermore, the high luminescence intensity made it easier to visualize the p53 translocation at a single cell level under a bioluminescence microscope. This p53 mitochondrial translocation assay is a new tool for high-throughput screening to identify novel p53 inhibitors, which could be developed as drugs to treat diseases in which necrotic cell death is a major contributor. © 2017 Wiley Periodicals, Inc.

  18. The Use of Plasma-Derived Complement C1-Esterase Inhibitor Concentrate (Berinert®) in the Treatment of Angiotensin Converting Enzyme-Inhibitor Related Angioedema

    DEFF Research Database (Denmark)

    Hermanrud, Thorbjørn; Duus, Nicolaj; Bygum, Anette

    2016-01-01

    concentrate is a well-established treatment option of hereditary and acquired complement C1-esterase inhibitor deficiency, which are also mediated by an increased level of bradykinin resulting in recurrent angioedema. We here present a case of severe angiotensin converting enzyme-inhibitor related angioedema...... (ACEi-AE) of the hypopharynx that completely resolved rapidly after the infusion of plasma-derived C1-inhibitor concentrate adding to the sparse reports in the existing literature.......Angioedema of the upper airways is a severe and potentially life-threatening condition. The incidence has been increasing in the past two decades, primarily due to pharmaceuticals influencing the generation or degradation of the vasoactive molecule bradykinin. Plasma-derived C1-esterase inhibitor...

  19. Virulence of Group A Streptococci Is Enhanced by Human Complement Inhibitors

    DEFF Research Database (Denmark)

    Ermert, David; Shaughnessy, Jutamas; Joeris, Thorsten

    2015-01-01

    Streptococcus pyogenes, also known as Group A Streptococcus (GAS), is an important human bacterial pathogen that can cause invasive infections. Once it colonizes its exclusively human host, GAS needs to surmount numerous innate immune defense mechanisms, including opsonization by complement...

  20. Complement C3 inhibitor Cp40 attenuates xenoreactions in pig hearts perfused with human blood.

    Science.gov (United States)

    Abicht, Jan-Michael; Kourtzelis, Ioannis; Reichart, Bruno; Koutsogiannaki, Sophia; Primikyri, Alexandra; Lambris, John D; Chavakis, Triantafyllos; Holdt, Lesca; Kind, Alexander; Guethoff, Sonja; Mayr, Tanja

    2017-01-01

    The complement system plays a crucial role in acute xenogeneic reactions after cardiac transplantation. We used an ex vivo perfusion model to investigate the effect of Cp40, a compstatin analog and potent inhibitor of complement at the level of C3. Fifteen wild-type pig hearts were explanted, cardiopleged, and reperfused ex vivo after 150 minutes of cold ischemia. Hearts were challenged in a biventricular working heart mode to evaluate cardiac perfusion and function. In the treatment group (n=5), the complement cascade was blocked at the level of C3 using Cp40, using diluted human blood. Untreated human and porcine blood was used for controls. Throughout the perfusion, C3 activation was inhibited when Cp40 was used (mean of all time points: 1.11 ± 0.34% vs 3.12 ± 0.48% control activation; Phearts xenoperfused ex vivo. We suggest that this compstatin analog, which blocks all main pathways of complement activation, could be a beneficial perioperative treatment in preclinical and in future clinical xenotransplantation. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Interactions of the humoral pattern recognition molecule PTX3 with the complement system

    DEFF Research Database (Denmark)

    Doni, Andrea; Garlanda, Cecilia; Bottazzi, Barbara

    2012-01-01

    The innate immune system comprises a cellular and a humoral arm. The long pentraxin PTX3 is a fluid phase pattern recognition molecule, which acts as an essential component of the humoral arm of innate immunity. PTX3 has antibody-like properties including interactions with complement components...... and factor H, the principal regulators of the classical, lectin and alternative complement pathways, show that PTX3 also may have a major influence on the regulation of the complement system. The complex interaction of PTX3 with the complement system at different levels has broad implications for host....... PTX3 interacts with C1q, ficolin-1 and ficolin-2 as well as mannose-binding lectin, recognition molecules in the classical and lectin complement pathways. The formation of these heterocomplexes results in cooperative pathogen recognition and complement activation. Interactions with C4b binding protein...

  2. Complement-Mediated Enhancement of Monocyte Adhesion to Endothelial Cells by HLA Antibodies, and Blockade by a Specific Inhibitor of the Classical Complement Cascade, TNT003

    Science.gov (United States)

    Valenzuela, Nicole M.; Thomas, Kimberly A.; Mulder, Arend; Parry, Graham C.; Panicker, Sandip; Reed, Elaine F.

    2017-01-01

    Background Antibody-mediated rejection (AMR) of most solid organs is characterized by evidence of complement activation and/or intragraft macrophages (C4d + and CD68+ biopsies). We previously demonstrated that crosslinking of HLA I by antibodies triggered endothelial activation and monocyte adhesion. We hypothesized that activation of the classical complement pathway at the endothelial cell surface by HLA antibodies would enhance monocyte adhesion through soluble split product generation, in parallel with direct endothelial activation downstream of HLA signaling. Methods Primary human aortic endothelial cells (HAEC) were stimulated with HLA class I antibodies in the presence of intact human serum complement. C3a and C5a generation, endothelial P-selectin expression, and adhesion of human primary and immortalized monocytes (Mono Mac 6) were measured. Alternatively, HAEC or monocytes were directly stimulated with purified C3a or C5a. Classical complement activation was inhibited by pretreatment of complement with an anti-C1s antibody (TNT003). Results Treatment of HAEC with HLA antibody and human complement increased the formation of C3a and C5a. Monocyte recruitment by human HLA antibodies was enhanced in the presence of intact human serum complement or purified C3a or C5a. Specific inhibition of the classical complement pathway using TNT003 or C1q-depleted serum significantly reduced adhesion of monocytes in the presence of human complement. Conclusions Despite persistent endothelial viability in the presence of HLA antibodies and complement, upstream complement anaphylatoxin production exacerbates endothelial exocytosis and leukocyte recruitment. Upstream inhibition of classical complement may be therapeutic to dampen mononuclear cell recruitment and endothelial activation characteristic of microvascular inflammation during AMR. PMID:28640789

  3. Bimolecular Complementation to Visualize Filovirus VP40-Host Complexes in Live Mammalian Cells: Toward the Identification of Budding Inhibitors

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    Yuliang Liu

    2011-01-01

    Full Text Available Virus-host interactions play key roles in promoting efficient egress of many RNA viruses, including Ebola virus (EBOV or “e” and Marburg virus (MARV or “m”. Late- (L- domains conserved in viral matrix proteins recruit specific host proteins, such as Tsg101 and Nedd4, to facilitate the budding process. These interactions serve as attractive targets for the development of broad-spectrum budding inhibitors. A major gap still exists in our understanding of the mechanism of filovirus budding due to the difficulty in detecting virus-host complexes and mapping their trafficking patterns in the natural environment of the cell. To address this gap, we used a bimolecular complementation (BiMC approach to detect, localize, and follow the trafficking patterns of eVP40-Tsg101 complexes in live mammalian cells. In addition, we used the BiMC approach along with a VLP budding assay to test small molecule inhibitors identified by in silico screening for their ability to block eVP40 PTAP-mediated interactions with Tsg101 and subsequent budding of eVP40 VLPs. We demonstrated the potential broad spectrum activity of a lead candidate inhibitor by demonstrating its ability to block PTAP-dependent binding of HIV-1 Gag to Tsg101 and subsequent egress of HIV-1 Gag VLPs.

  4. Safety and Efficacy of the Complement Inhibitor AMY-101 in a Natural Model of Periodontitis in Non-human Primates

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    Tetsuhiro Kajikawa

    2017-09-01

    Full Text Available Periodontitis is a chronic inflammatory disease associated with overactivation of the complement system. Recent preclinical studies suggest that host-modulation therapies may contribute to effective treatment of human periodontitis, which may lead to loss of teeth and function if untreated. We previously showed that locally administered AMY-101 (Cp40, a peptidic inhibitor of the central complement component C3, can inhibit naturally occurring periodontitis in non-human primates (NHPs when given once a week. This study was undertaken to determine the local safety of increasing doses of the drug as well as its efficacy when given at a reduced frequency or after systemic administration. Our findings have determined a local dose of AMY-101 (0.1 mg/site that is free of local irritation and effective when given once every 3 weeks. Moreover, a daily subcutaneous dose of AMY-101 (4 mg/kg bodyweight was protective against NHP periodontitis, suggesting that patients treated for systemic disorders (e.g., paroxysmal nocturnal hemoglobinuria can additionally benefit in terms of improved periodontal condition. In summary, AMY-101 appears to be a promising candidate drug for the adjunctive treatment of human periodontitis, a notion that merits investigation in human clinical trials.

  5. Isolation and properties of a complement inhibitor from Naja haje venom, distinct from known anticomplementary factors in cobra venom.

    Science.gov (United States)

    von Zabern, I; Przyklenk, H; Damerau, B; Zimmermann, B

    1981-08-01

    A complement inhibitor (CI) has been isolated from cobra (Naja haje) venom which is distinct from the two known anticomplementary factors in cobra venom [1], in functional properties as well as structure. CI is a small (mol. wt 26,000, determined by sodium dodecyl sulphate gel electrophoresis), heat-labile glycoprotein; the amino acid composition is that of a globular protein. CI interferes at various steps of the complement sequence, including reactions of the classical and alternative pathway. No effect was observed on C4 fixation and on the assembly of the membrane attack complex from C6-9 (minor inhibiting effects, if present, have not been excluded). Initiation of the alternative pathway is inhibited by CI already at the stage of cleavage of factor B. CI binds to C4, C4b, C3 and C3b; since the major inhibitory action of CI is lost after washing of cell intermediates, complex formation and, as a consequence, steric hindrance may be responsible for the inhibiting effects of CI. CI also interferes with binding of C3b to C3b receptors on human erythrocytes. CI is non-toxic in mice when given intraperitoneally in doses of 5 microgram/g.

  6. Genetically engineered fusion of MAP-1 and factor H domains 1-5 generates a potent dual upstream inhibitor of both the lectin and alternative complement pathways

    DEFF Research Database (Denmark)

    Nordmaj, Mie Anemone; Munthe-Fog, Lea; Hein, Estrid

    2015-01-01

    Inhibition of the complement cascade has emerged as an option for treatment of a range of diseases. Mannose-binding lectin/ficolin/collectin-associated protein (MAP-1) is a pattern recognition molecule (PRM)-associated inhibitor of the lectin pathway. The central regulator of the alternative path...

  7. Brown Recluse Spider Bite Mediated Hemolysis: Clinical Features, a Possible Role for Complement Inhibitor Therapy, and Reduced RBC Surface Glycophorin A as a Potential Biomarker of Venom Exposure

    OpenAIRE

    Gehrie, Eric A.; Hui Nian; Young, Pampee P

    2013-01-01

    BACKGROUND: The venom of Loxosceles reclusa (Brown Recluse spider) can cause a severe, life-threatening hemolysis in humans for which no therapy is currently available in the USA beyond supportive measures. Because this hemolysis is uncommon, relatively little is known about its clinical manifestation, diagnosis, or management. Here, we aimed to clarify the clinical details of envenomation, to determine the efficacy of the complement inhibitor eculizumab to prevent the hemolysis in vitro, and...

  8. Brown Recluse spider bite mediated hemolysis: clinical features, a possible role for complement inhibitor therapy, and reduced RBC surface glycophorin A as a potential biomarker of venom exposure.

    Directory of Open Access Journals (Sweden)

    Eric A Gehrie

    Full Text Available The venom of Loxosceles reclusa (Brown Recluse spider can cause a severe, life-threatening hemolysis in humans for which no therapy is currently available in the USA beyond supportive measures. Because this hemolysis is uncommon, relatively little is known about its clinical manifestation, diagnosis, or management. Here, we aimed to clarify the clinical details of envenomation, to determine the efficacy of the complement inhibitor eculizumab to prevent the hemolysis in vitro, and to investigate markers of exposure to Brown Recluse venom.We performed a 10-year chart review of cases of Brown Recluse spider bite-mediated hemolysis at our institution. We also designed an in vitro assay to test the efficacy of eculizumab to inhibit hemolysis of venom exposed red blood cells. Finally, we compared levels of CD55, CD59 and glycophorin A on venom exposed versus venom-naïve cells.Most victims of severe Brown Recluse spider mediated hemolysis at our institution are children and follow an unpredictable clinical course. Brown Recluse spider bite mediated hemolysis is reduced by 79.2% (SD=18.8% by eculizumab in vitro. Erythrocyte glycophorin A, but not CD55 or CD59, is reduced after red blood cells are incubated with venom in vitro.Taken together, our laboratory data and clinical observations indicate that L. reclusa venom exposure results in non-specific antibody and complement fixation on red blood cells, resulting in complement mediated hemolysis that is curtailed by the complement inhibitor eculizumab in vitro. Glycophorin A measurement by flow cytometry may help to identify victims of L. reclusa envenomation.

  9. Brown Recluse spider bite mediated hemolysis: clinical features, a possible role for complement inhibitor therapy, and reduced RBC surface glycophorin A as a potential biomarker of venom exposure.

    Science.gov (United States)

    Gehrie, Eric A; Nian, Hui; Young, Pampee P

    2013-01-01

    The venom of Loxosceles reclusa (Brown Recluse spider) can cause a severe, life-threatening hemolysis in humans for which no therapy is currently available in the USA beyond supportive measures. Because this hemolysis is uncommon, relatively little is known about its clinical manifestation, diagnosis, or management. Here, we aimed to clarify the clinical details of envenomation, to determine the efficacy of the complement inhibitor eculizumab to prevent the hemolysis in vitro, and to investigate markers of exposure to Brown Recluse venom. We performed a 10-year chart review of cases of Brown Recluse spider bite-mediated hemolysis at our institution. We also designed an in vitro assay to test the efficacy of eculizumab to inhibit hemolysis of venom exposed red blood cells. Finally, we compared levels of CD55, CD59 and glycophorin A on venom exposed versus venom-naïve cells. Most victims of severe Brown Recluse spider mediated hemolysis at our institution are children and follow an unpredictable clinical course. Brown Recluse spider bite mediated hemolysis is reduced by 79.2% (SD=18.8%) by eculizumab in vitro. Erythrocyte glycophorin A, but not CD55 or CD59, is reduced after red blood cells are incubated with venom in vitro. Taken together, our laboratory data and clinical observations indicate that L. reclusa venom exposure results in non-specific antibody and complement fixation on red blood cells, resulting in complement mediated hemolysis that is curtailed by the complement inhibitor eculizumab in vitro. Glycophorin A measurement by flow cytometry may help to identify victims of L. reclusa envenomation.

  10. Changes in blood levels of proteinase inhibitors, pregnancy zone protein, steroid carriers and complement factors induced by oral contraceptives

    DEFF Research Database (Denmark)

    Nielsen, C H; Poulsen, H K; Teisner, B

    1993-01-01

    levels of antithrombin III (AT III), alpha 2-macroglobulin (alpha 2M) alpha 1-antitrypsin (alpha 1at), complement factors (factor B, C3, C4), pregnancy zone protein (PZP), corticosteroid binding globulin (CBG), sex hormone binding globulin (SHBG) and albumin were measured before treatment and during...

  11. Transgenic mice overexpressing the complement inhibitor crry as a soluble protein are protected from antibody-induced glomerular injury.

    Science.gov (United States)

    Quigg, R J; He, C; Lim, A; Berthiaume, D; Alexander, J J; Kraus, D; Holers, V M

    1998-10-05

    Complement receptor 1-related gene/protein y (Crry) is a potent murine membrane complement regulator that inhibits classical and alternative pathway C3 convertases. In nephrotoxic serum (NTS) nephritis, injected antibodies (Abs) bind to glomeruli, leading to complement activation and subsequent glomerular injury and albuminuria. To study the phenotypic effects of continuous complement pathway blockade, transgenic mice were created that express recombinant soluble (rs) Crry directed by the broadly active and heavy metal-inducible metallothionein-I promoter. One transgenic line expressing high levels of rsCrry was propagated. Serum rsCrry levels were 18.7 +/- 2.7 microg/ml (n = 5) at basal level and increased to 118.1 +/- 20.6 microg/ml 4 d after addition of zinc to the drinking water. By reverse transcription polymerase chain reaction (RT-PCR), transgene messenger (m)RNA was present in liver, kidney, brain, lung, and spleen, but not in heart. By in situ RT-PCR analysis of kidneys, transgene mRNA was widely expressed both in renal glomeruli and tubules. Urinary excretion of rsCrry was 113.4 +/- 22.4 microg/ml with a fractional excretion relative to creatinine of 13.2 +/- 2.7%, consistent with local renal production of rsCrry and secretion into urine. The founder and all transgene positive adult animals have remained healthy with no mortality or apparent phenotypic abnormalities, including infection or immune complex disease. To determine whether rsCrry blocked complement-mediated injury, NTS nephritis was induced by injection of NTS immunoglobulin (Ig)G, followed by an 18-h urine collection to quantitate the excretion of albumin as a measure of glomerular injury. In transgene-negative littermates (n = 15), transgene-positive animals (n = 10), and transgene-positive animals fed zinc (n = 10), albuminuria was 4,393 +/- 948, 1,783 +/- 454, and 1,057 +/- 277 microg/mg creatinine, respectively (P Ab-induced disease model in vivo. These results support the hypothesis that

  12. Treatment of a patient with classical paroxysmal nocturnal hemoglobinuria and Budd-Chiari syndrome, with complement inhibitor eculizumab: Case Report

    Science.gov (United States)

    Mandala, E; Lafaras, C; Goulis, I; Tsioni, K; Georgopoulou, V; Ilonidis, G

    2013-01-01

    Background. Paroxysmal nocturnal haemoglobinuria (PNH) is a rare acquired clonal disorder of hematopoietic stem cells involving all blood cells. Erythrocytes have increased susceptibility to complement-mediated haemolysis. Thrombosis is the leading cause of mortality and follows episodes of acute hemolysis. Eculizumab, a monoclonal antibody blocking activation of complement C5 is currently used in the treatment of PNH. Recent results demonstrated that eculizumab effectively reduces thrombosis. Description of case. We present a 30-year-old male patient admitted with abdominal and lumbar pain. Thorough investigation revealed severe hemolytic anemia requiring transfusions and hepatosplenomegaly. Imaging findings were compatible with a Budd-Chiari syndrome. Flow cytometry confirmed the PNH diagnosis. Due to refractory ascites he underwent a transjugular intrahepatic portal-systemic shunt (TIPS) and eculizumab administration was started. Results. He has already completed three years of eculizumab treatment and he is transfusion independent. There is also a significant reduction in fatigue with improvement in his quality of life. Doppler scans of his TIPS persistently show it to be patent. Conclusions. Classical PNH patients with thrombosis and severe intravascular hemolysis are particularly challenging to manage. For these patients, eculizumab is a reasonable therapeutic option, expecting that by decreasing the risk for thrombosis, life expectancy may be increased. PMID:23935352

  13. Molecular analysis of the murine C4b-binding protein gene. Chromosome assignment and partial gene organization

    DEFF Research Database (Denmark)

    Barum, Scott B; Kristensen, Torsten; Chaplin, David D

    1989-01-01

    the nonrepeat and untranslated region spans approximately 12 kb; however, genomic Southern blot analysis suggests that the gene is between 20 and 30 kb in length. Analysis of the 3' genomic sequence demonstrates that this region of the gene has homology with SV-40 late (class II) RNA sequences....

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

    Science.gov (United States)

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

    2013-12-01

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

  15. Inhibitors

    Science.gov (United States)

    ... and exercise, immune tolerance therapy, and needs of older adults with hemophilia and an inhibitor. For more information, visit https://www.hemophilia.org/Events-Educational-Programs/Inhibitor-Education/Inhibitor-Education-Summits The NHF’s Inhibitor Education Summits ...

  16. Overcoming bortezomib resistance in human B cells by anti-CD20/rituximab-mediated complement-dependent cytotoxicity and epoxyketone-based irreversible proteasome inhibitors

    Directory of Open Access Journals (Sweden)

    Verbrugge Sue Ellen

    2013-01-01

    Full Text Available Abstract Background In clinical and experimental settings, antibody-based anti-CD20/rituximab and small molecule proteasome inhibitor (PI bortezomib (BTZ treatment proved effective modalities for B cell depletion in lymphoproliferative disorders as well as autoimmune diseases. However, the chronic nature of these diseases requires either prolonged or re-treatment, often with acquired resistance as a consequence. Methods Here we studied the molecular basis of acquired resistance to BTZ in JY human B lymphoblastic cells following prolonged exposure to this drug and examined possibilities to overcome resistance by next generation PIs and anti-CD20/rituximab-mediated complement-dependent cytotoxicity (CDC. Results Characterization of BTZ-resistant JY/BTZ cells compared to parental JY/WT cells revealed the following features: (a 10–12 fold resistance to BTZ associated with the acquisition of a mutation in the PSMB5 gene (encoding the constitutive β5 proteasome subunit introducing an amino acid substitution (Met45Ile in the BTZ-binding pocket, (b a significant 2–4 fold increase in the mRNA and protein levels of the constitutive β5 proteasome subunit along with unaltered immunoproteasome expression, (c full sensitivity to the irreversible epoxyketone-based PIs carfilzomib and (to a lesser extent the immunoproteasome inhibitor ONX 0914. Finally, in association with impaired ubiquitination and attenuated breakdown of CD20, JY/BTZ cells harbored a net 3-fold increase in CD20 cell surface expression, which was functionally implicated in conferring a significantly increased anti-CD20/rituximab-mediated CDC. Conclusions These results demonstrate that acquired resistance to BTZ in B cells can be overcome by next generation PIs and by anti-CD20/rituximab-induced CDC, thereby paving the way for salvage therapy in BTZ-resistant disease.

  17. Deletion of the Monkeypox Virus Inhibitor of Complement Enzymes Locus Impacts the Adaptive Immune Response to Monkeypox Virus in a Nonhuman Primate Model of Infection ▿ §

    Science.gov (United States)

    Estep, Ryan D.; Messaoudi, Ilhem; O'Connor, Megan A.; Li, Helen; Sprague, Jerald; Barron, Alexander; Engelmann, Flora; Yen, Bonnie; Powers, Michael F.; Jones, John M.; Robinson, Bridget A.; Orzechowska, Beata U.; Manoharan, Minsha; Legasse, Alfred; Planer, Shannon; Wilk, Jennifer; Axthelm, Michael K.; Wong, Scott W.

    2011-01-01

    Monkeypox virus (MPXV) is an orthopoxvirus closely related to variola virus, the causative agent of smallpox. Human MPXV infection results in a disease that is similar to smallpox and can also be fatal. Two clades of MPXV have been identified, with viruses of the central African clade displaying more pathogenic properties than those within the west African clade. The monkeypox inhibitor of complement enzymes (MOPICE), which is not expressed by viruses of the west African clade, has been hypothesized to be a main virulence factor responsible for increased pathogenic properties of central African strains of MPXV. To gain a better understanding of the role of MOPICE during MPXV-mediated disease, we compared the host adaptive immune response and disease severity following intrabronchial infection with MPXV-Zaire (n = 4), or a recombinant MPXV-Zaire (n = 4) lacking expression of MOPICE in rhesus macaques (RM). Data presented here demonstrate that infection of RM with MPXV leads to significant viral replication in the peripheral blood and lungs and results in the induction of a robust and sustained adaptive immune response against the virus. More importantly, we show that the loss of MOPICE expression results in enhanced viral replication in vivo, as well as a dampened adaptive immune response against MPXV. Taken together, these findings suggest that MOPICE modulates the anti-MPXV immune response and that this protein is not the sole virulence factor of the central African clade of MPXV. PMID:21752919

  18. The innate immune modulators staphylococcal complement inhibitor and chemotaxis inhibitory protein of Staphylococcus aureus are located on beta-hemolysin-converting bacteriophages.

    Science.gov (United States)

    van Wamel, Willem J B; Rooijakkers, Suzan H M; Ruyken, Maartje; van Kessel, Kok P M; van Strijp, Jos A G

    2006-02-01

    Two newly discovered immune modulators, chemotaxis inhibitory protein of Staphylococcus aureus (CHIPS) and staphylococcal complement inhibitor (SCIN), cluster on the conserved 3' end of beta-hemolysin (hlb)-converting bacteriophages (betaC-phis). Since these betaC-phis also carry the genes for the immune evasion molecules staphylokinase (sak) and enterotoxin A (sea), this 8-kb region at the 3' end of betaC-phi represents an innate immune evasion cluster (IEC). By PCR and Southern analyses of 85 clinical Staphylococcus aureus strains and 5 classical laboratory strains, we show that 90% of S. aureus strains carry a betaC-phi with an IEC. Seven IEC variants were discovered, carrying different combinations of chp, sak, or sea (or sep), always in the same 5'-to-3' orientation and on the 3' end of a betaC-phi. From most IEC variants we could isolate active bacteriophages by mitomycin C treatment, of which lysogens were generated in S. aureus R5 (broad phage host). All IEC-carrying bacteriophages integrated into hlb, as was measured by Southern blotting of R5 lysogens. Large quantities of the different bacteriophages were obtained by mitomycin C treatment of the lysogens, and bacteriophages were collected and used to reinfect all lysogenic R5 strains. In total, five lytic families were found. Furthermore, phage DNA was isolated and digested with EcoR1, revealing that one IEC variant can be found on different betaI-phis. In conclusion, the four human-specific innate immune modulators SCIN, CHIPS, SAK, and SEA form an IEC that is easily transferred among S. aureus strains by a diverse group of beta-hemolysin-converting bacteriophages.

  19. Generation of complement molecular complex C5b-9 (C5b-9) in response to poly-traumatic hemorrhagic shock and evaluation of C5 cleavage inhibitors in non-human primates.

    Science.gov (United States)

    Paredes, R Madelaine; Reyna, Sarah; Vernon, Philip; Tadaki, Douglas K; Dallelucca, Jurandir J; Sheppard, Forest

    2018-01-01

    Severe trauma initiates a systemic inflammatory cascade and that involves early activation of complement and cleavage of C5 into C5a (anaphylatoxin) and C5b (C5b-9 membrane attack complex). We examined activation of C5 in non-human primate (NHP) models of hemorrhagic shock. Blood plasma concentrations of C5b-9 were significantly increased in NHPs in response to hemorrhage alone and were further increased with the addition of tissue trauma. The onset of increased C5 cleavage was accelerated in NHPs that experienced decompensated poly-traumatic hemorrhagic shock. Next, to identify an effective inhibitor of NHP C5 cleavage in vitro, as a first step in the development of a potential therapy, three inhibitors of human C5 cleavage and hemolysis were tested in vitro. NHP C5 cleavage and complement-mediated hemolysis were successfully inhibited by pre-treatment of serum samples with a small, inhibitory peptide RA101348. Commercially-available C5 inhibitory antibodies were found to exhibit species-specific efficacy in vitro. Quidel's A217 antibody demonstrated dose-dependent inhibition of C5 cleavage and hemolysis in NHP samples, whereas LGM-Eculizumab only inhibited complement-mediated hemolysis in human samples. This study shows that complement activation in NHPs following experimental poly-traumatic hemorrhagic shock is consistent with clinical reports, and that cleavage of C5 and complement-mediated hemolysis can be effectively inhibited in vitro using a small peptide inhibitor. Taken together, these findings offer a clinically-relevant vehicle and a potential strategy for treatment of hemorrhagic shock with poly-traumatic injury. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Acquisition of negative complement regulators by the saprophyte Leptospira biflexa expressing LigA or LigB confers enhanced survival in human serum.

    Science.gov (United States)

    Castiblanco-Valencia, Mónica M; Fraga, Tatiana R; Breda, Leandro C D; Vasconcellos, Sílvio A; Figueira, Cláudio P; Picardeau, Mathieu; Wunder, Elsio; Ko, Albert I; Barbosa, Angela S; Isaac, Lourdes

    2016-05-01

    Leptospiral immunoglobulin-like (Lig) proteins are surface exposed molecules present in pathogenic but not in saprophytic Leptospira species. We have previously shown that Lig proteins interact with the soluble complement regulators Factor H (FH), FH like-1 (FHL-1), FH related-1 (FHR-1) and C4b Binding Protein (C4BP). In this study, we used the saprophyte L. biflexa serovar Patoc as a surrogate host to address the specific role of LigA and LigB proteins in leptospiral complement evasion. L. biflexa expressing LigA or LigB was able to acquire FH and C4BP. Bound complement regulators retained their cofactor activities of FI in the proteolytic cleavage of C3b and C4b. Moreover, heterologous expression of ligA and ligB genes in the saprophyte L. biflexa enhanced bacterial survival in human serum. Complement deposition on lig-transformed L. biflexa was assessed by flow cytometry analysis. With regard to MAC deposition, L. biflexa expressing LigA or LigB presented an intermediate profile: MAC deposition levels were greater than those found in the pathogenic L. interrogans, but lower than those observed for L. biflexa wildtype. In conclusion, Lig proteins contribute to in vitro control of complement activation on the leptospiral surface, promoting an increased bacterial survival in human serum. Copyright © 2016 European Federation of Immunological Societies. All rights reserved.

  1. A tick mannose-binding lectin inhibitor interferes with the vertebrate complement cascade to enhance transmission of the lyme disease agent

    NARCIS (Netherlands)

    Schuijt, Tim J.; Coumou, Jeroen; Narasimhan, Sukanya; Dai, Jianfeng; Deponte, Kathleen; Wouters, Diana; Brouwer, Mieke; Oei, Anneke; Roelofs, Joris J. T. H.; van Dam, Alje P.; van der Poll, Tom; van't Veer, Cornelis; Hovius, Joppe W.; Fikrig, Erol

    2011-01-01

    The Lyme disease agent Borrelia burgdorferi is primarily transmitted to vertebrates by Ixodes ticks. The classical and alternative complement pathways are important in Borrelia eradication by the vertebrate host. We recently identified a tick salivary protein, designated P8, which reduced

  2. Conserved Patterns of Microbial Immune Escape: Pathogenic Microbes of Diverse Origin Target the Human Terminal Complement Inhibitor Vitronectin via a Single Common Motif.

    Directory of Open Access Journals (Sweden)

    Teresia Hallström

    Full Text Available Pathogenicity of many microbes relies on their capacity to resist innate immunity, and to survive and persist in an immunocompetent human host microbes have developed highly efficient and sophisticated complement evasion strategies. Here we show that different human pathogens including Gram-negative and Gram-positive bacteria, as well as the fungal pathogen Candida albicans, acquire the human terminal complement regulator vitronectin to their surface. By using truncated vitronectin fragments we found that all analyzed microbial pathogens (n = 13 bound human vitronectin via the same C-terminal heparin-binding domain (amino acids 352-374. This specific interaction leaves the terminal complement complex (TCC regulatory region of vitronectin accessible, allowing inhibition of C5b-7 membrane insertion and C9 polymerization. Vitronectin complexed with the various microbes and corresponding proteins was thus functionally active and inhibited complement-mediated C5b-9 deposition. Taken together, diverse microbial pathogens expressing different structurally unrelated vitronectin-binding molecules interact with host vitronectin via the same conserved region to allow versatile control of the host innate immune response.

  3. Complement receptor type 1 (CR1, CD35) is a potent inhibitor of B-cell functions in rheumatoid arthritis patients.

    Science.gov (United States)

    Kremlitzka, Mariann; Polgár, Anna; Fülöp, Lívia; Kiss, Emese; Poór, Gyula; Erdei, Anna

    2013-01-01

    The involvement of B cells, complement activation and subsequent immune complex deposition has all been implicated in the pathogenesis of rheumatoid arthritis (RA). Although the reduced expression of complement receptor 1 (CR1, CD35) and 2 (CR2, CD21) on the B cells of RA patients has been known for a long time, their exact role in B-cell tolerance and autoimmunity is not yet fully understood. To get a deeper insight into the possible mechanisms, we studied the expression and function of CR1 and CR2 on various subsets of B cells of healthy donors and RA patients at various stages of the disease by FACS analysis, (3)H-thymidine incorporation and ELISA. We found that CD19(+)CD27(-) naive B cells up-regulate the expression of the inhibitory CR1 during differentiation to CD19(+)CD27(+) memory B cells both in healthy donors and in RA patients, whereas the expression of the activatory CR2 is down-regulated. This clearly demonstrates that the expression of these two antagonistic complement receptors is regulated differentially during the development of human B cells, a phenomenon which may influence the maintenance of peripheral B-cell tolerance. Our functional studies show that after clustering CR1 both by its natural ligand and To5 mAb, the inhibitory function of CD35 is maintained in RA patients, despite its significantly reduced expression compared with healthy individuals. Besides blocking B-cell receptor-induced proliferation, CR1 inhibits the differentiation of B cells to plasmablasts and their immunoglobulin production. Since the reduced expression of CR1 in RA patients does not affect its inhibitory function, this receptor might serve as a new target for therapeutical interventions.

  4. 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 patie...

  5. Complement Inhibitory Proteins and Their Role in Tumorigenesis

    National Research Council Canada - National Science Library

    Tomlinson, Stephen

    2001-01-01

    Complement is a major effector mechanism of the immune system. Membrane complement inhibitors on the surface of breast tumor cells, may play a crucial role in determining tumorigenesis and the outcome of antibody-mediated immunotherapy...

  6. Discovery, linkage disequilibrium and association analyses of polymorphisms of the immune complement inhibitor, decay-accelerating factor gene (DAF/CD55 in type 1 diabetes

    Directory of Open Access Journals (Sweden)

    Smink Luc J

    2006-04-01

    Full Text Available Abstract Background Type 1 diabetes (T1D is a common autoimmune disease resulting from T-cell mediated destruction of pancreatic beta cells. Decay accelerating factor (DAF, CD55, a glycosylphosphatidylinositol-anchored membrane protein, is a candidate for autoimmune disease susceptibility based on its role in restricting complement activation and evidence that DAF expression modulates the phenotype of mice models for autoimmune disease. In this study, we adopt a linkage disequilibrium (LD mapping approach to test for an association between the DAF gene and T1D. Results Initially, we used HapMap II genotype data to examine LD across the DAF region. Additional resequencing was required, identifying 16 novel polymorphisms. Combining both datasets, a LD mapping approach was adopted to test for association with T1D. Seven tag SNPs were selected and genotyped in case-control (3,523 cases and 3,817 controls and family (725 families collections. Conclusion We obtained no evidence of association between T1D and the DAF region in two independent collections. In addition, we assessed the impact of using only HapMap II genotypes for the selection of tag SNPs and, based on this study, found that HapMap II genotypes may require additional SNP discovery for comprehensive LD mapping of some genes in common disease.

  7. Complement component 4

    Science.gov (United States)

    ... certain protein. This protein is part of the complement system. The complement system is a group of proteins that move freely ... a role in the development of inflammation. The complement system protects the body from infections, dead cells and ...

  8. Elucidating the role of the complement control protein in monkeypox pathogenicity.

    Directory of Open Access Journals (Sweden)

    Paul N Hudson

    Full Text Available Monkeypox virus (MPXV causes a smallpox-like disease in humans. Clinical and epidemiological studies provide evidence of pathogenicity differences between two geographically distinct monkeypox virus clades: the West African and Congo Basin. Genomic analysis of strains from both clades identified a ∼10 kbp deletion in the less virulent West African isolates sequenced to date. One absent open reading frame encodes the monkeypox virus homologue of the complement control protein (CCP. This modulatory protein prevents the initiation of both the classical and alternative pathways of complement activation. In monkeypox virus, CCP, also known as MOPICE, is a ∼24 kDa secretory protein with sequence homology to this superfamily of proteins. Here we investigate CCP expression and its role in monkeypox virulence and pathogenesis. CCP was incorporated into the West African strain and removed from the Congo Basin strain by homologous recombination. CCP expression phenotypes were confirmed for both wild type and recombinant monkeypox viruses and CCP activity was confirmed using a C4b binding assay. To characterize the disease, prairie dogs were intranasally infected and disease progression was monitored for 30 days. Removal of CCP from the Congo Basin strain reduced monkeypox disease morbidity and mortality, but did not significantly decrease viral load. The inclusion of CCP in the West African strain produced changes in disease manifestation, but had no apparent effect on disease-associated mortality. This study identifies CCP as an important immuno-modulatory protein in monkeypox pathogenesis but not solely responsible for the increased virulence seen within the Congo Basin clade of monkeypox virus.

  9. The Complement System

    OpenAIRE

    Sarma, J. Vidya; Ward, Peter A.

    2010-01-01

    The complement system consists of a tightly regulated network of proteins that play an important role in host defense and inflammation. Complement activation results in opsonization of pathogens and their removal by phagocytes, as well as cell lysis. Inappropriate complement activation and complement deficiencies are the underlying cause of the pathophysiology of many diseases such as systemic lupus erythematosus and asthma. This review represents an overview of the complement system in an ef...

  10. The Complement System in Dialysis : A Forgotten Story?

    NARCIS (Netherlands)

    Poppelaars, Felix; Faria, Bernardo; da Costa, Mariana Gaya; Franssen, Casper F. M.; van Son, Willem J.; Berger, Stefan P.; Daha, Mohamed R.; Seelen, Marc A.

    2018-01-01

    Significant advances have lead to a greater understanding of the role of the complement system within nephrology. The success of the first clinically approved complement inhibitor has created renewed appreciation of complement-targeting therapeutics. Several clinical trials are currently underway to

  11. Forcefield_NCAA: Ab Initio Charge Parameters to Aid in the Discovery and Design of Therapeutic Proteins and Peptides with Unnatural Amino Acids and Their Application to Complement Inhibitors of the Compstatin Family

    Science.gov (United States)

    2015-01-01

    We describe the development and testing of ab initio derived, AMBER ff03 compatible charge parameters for a large library of 147 noncanonical amino acids including β- and N-methylated amino acids for use in applications such as protein structure prediction and de novo protein design. The charge parameter derivation was performed using the RESP fitting approach. Studies were performed assessing the suitability of the derived charge parameters in discriminating the activity/inactivity between 63 analogs of the complement inhibitor Compstatin on the basis of previously published experimental IC50 data and a screening procedure involving short simulations and binding free energy calculations. We found that both the approximate binding affinity (K*) and the binding free energy calculated through MM-GBSA are capable of discriminating between active and inactive Compstatin analogs, with MM-GBSA performing significantly better. Key interactions between the most potent Compstatin analog that contains a noncanonical amino acid are presented and compared to the most potent analog containing only natural amino acids and native Compstatin. We make the derived parameters and an associated web interface that is capable of performing modifications on proteins using Forcefield_NCAA and outputting AMBER-ready topology and parameter files freely available for academic use at http://selene.princeton.edu/FFNCAA. The forcefield allows one to incorporate these customized amino acids into design applications with control over size, van der Waals, and electrostatic interactions. PMID:24932669

  12. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Endogenous Natural Complement Inhibitor Regulates Cardiac Development

    DEFF Research Database (Denmark)

    Mortensen, Simon A; Skov, Louise L; Kjaer-Sorensen, Kasper

    2017-01-01

    Congenital heart defects are a major cause of perinatal mortality and morbidity, affecting >1% of all live births in the Western world, yet a large fraction of such defects have an unknown etiology. Recent studies demonstrated surprising dual roles for immune-related molecules and their effector...... protease (MASP)-3/collectin-L1/K1 hetero-oligomer, which impacts cardiac neural crest cell migration. We used knockdown and rescue strategies in zebrafish, a model allowing visualization and assessment of heart function, even in the presence of severe functional defects. Knockdown of embryonic expression...... of MAp44 caused impaired cardiogenesis, lowered heart rate, and decreased cardiac output. These defects were associated with aberrant neural crest cell behavior. We found that MAp44 competed with MASP-3 for pattern recognition molecule interaction, and knockdown of endogenous MAp44 expression could...

  14. Characterization of Pharmacologic and Pharmacokinetic Properties of CCX168, a Potent and Selective Orally Administered Complement 5a Receptor Inhibitor, Based on Preclinical Evaluation and Randomized Phase 1 Clinical Study.

    Science.gov (United States)

    Bekker, Pirow; Dairaghi, Daniel; Seitz, Lisa; Leleti, Manmohan; Wang, Yu; Ertl, Linda; Baumgart, Trageen; Shugarts, Sarah; Lohr, Lisa; Dang, Ton; Miao, Shichang; Zeng, Yibin; Fan, Pingchen; Zhang, Penglie; Johnson, Daniel; Powers, Jay; Jaen, Juan; Charo, Israel; Schall, Thomas J

    2016-01-01

    The complement 5a receptor has been an attractive therapeutic target for many autoimmune and inflammatory disorders. However, development of a selective and potent C5aR antagonist has been challenging. Here we describe the characterization of CCX168 (avacopan), an orally administered selective and potent C5aR inhibitor. CCX168 blocked the C5a binding, C5a-mediated migration, calcium mobilization, and CD11b upregulation in U937 cells as well as in freshly isolated human neutrophils. CCX168 retains high potency when present in human blood. A transgenic human C5aR knock-in mouse model allowed comparison of the in vitro and in vivo efficacy of the molecule. CCX168 effectively blocked migration in in vitro and ex vivo chemotaxis assays, and it blocked the C5a-mediated neutrophil vascular endothelial margination. CCX168 was effective in migration and neutrophil margination assays in cynomolgus monkeys. This thorough in vitro and preclinical characterization enabled progression of CCX168 into the clinic and testing of its safety, tolerability, pharmacokinetic, and pharmacodynamic profiles in a Phase 1 clinical trial in 48 healthy volunteers. CCX168 was shown to be well tolerated across a broad dose range (1 to 100 mg) and it showed dose-dependent pharmacokinetics. An oral dose of 30 mg CCX168 given twice daily blocked the C5a-induced upregulation of CD11b in circulating neutrophils by 94% or greater throughout the entire day, demonstrating essentially complete target coverage. This dose regimen is being tested in clinical trials in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis. Trial Registration ISRCTN registry with trial ID ISRCTN13564773.

  15. Binding of complement proteins C1q and C4bp to serum amyloid P component (SAP) in solid contra liquid phase

    DEFF Research Database (Denmark)

    Sørensen, Inge Juul; Nielsen, EH; Andersen, Ove

    1996-01-01

    Serum amyloid P component (SAP), a member of the conserved pentraxin family of plasma proteins, binds calcium dependently to its ligands. The authors investigated SAPs interaction with the complement proteins C4b binding protein (C4bp) and C1q by ELISA, immunoelectrophoresis and electron microscopy....... Binding of these proteins to SAP was demonstrated when SAP was immobilized using F(ab')2 anti-SAP, but not when SAP reacted with these proteins in liquid phase; thus the binding to human SAP was markedly phase state dependent. Presaturation of solid phase SAP with heparin, which binds SAP with high...... affinity, did not interfere with the subsequent binding of C4bp or C1q to SAP. In contrast, collagen I and IV showed partial competition with the binding of C1q to SAP. Using fresh serum, immobilized native SAP bound C4bp whereas binding of C1q/C1 could not be demonstrated. Altogether the results indicate...

  16. Soluble complement receptor 1 protects the peripheral nerve from early axon loss after injury

    NARCIS (Netherlands)

    Ramaglia, Valeria; Wolterman, Ruud; de Kok, Maryla; Vigar, Miriam Ann; Wagenaar-Bos, Ineke; King, Rosalind Helen Mary; Morgan, Brian Paul; Baas, Frank

    2008-01-01

    Complement activation is a crucial early event in Wallerian degeneration. In this study we show that treatment of rats with soluble complement receptor 1 (sCR1), an inhibitor of all complement pathways, blocked both systemic and local complement activation after crush injury of the sciatic nerve.

  17. Can Nondeterminism Help Complementation?

    Directory of Open Access Journals (Sweden)

    Yang Cai

    2012-10-01

    Full Text Available Complementation and determinization are two fundamental notions in automata theory. The close relationship between the two has been well observed in the literature. In the case of nondeterministic finite automata on finite words (NFA, complementation and determinization have the same state complexity, namely Theta(2^n where n is the state size. The same similarity between determinization and complementation was found for Buchi automata, where both operations were shown to have 2^Θ(n lg n state complexity. An intriguing question is whether there exists a type of omega-automata whose determinization is considerably harder than its complementation. In this paper, we show that for all common types of omega-automata, the determinization problem has the same state complexity as the corresponding complementation problem at the granularity of 2^Θ(..

  18. 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. Copyright © 2015 by The American Association of Immunologists, Inc.

  19. A vital role for complement in heart disease

    DEFF Research Database (Denmark)

    Lappegård, Knut T; Garred, Peter; Jonasson, Lena

    2014-01-01

    fibrillation often share risk factors both with coronary heart disease and heart failure, and there is some evidence implicating complement activation in atrial fibrillation. Moreover, Chagas heart disease, a protozoal infection, is an important cause of heart failure in Latin America, and the complement......Heart diseases are common and significant contributors to worldwide mortality and morbidity. During recent years complement mediated inflammation has been shown to be an important player in a variety of heart diseases. Despite some negative results from clinical trials using complement inhibitors......, emerging evidence points to an association between the complement system and heart diseases. Thus, complement seems to be important in coronary heart disease as well as in heart failure, where several studies underscore the prognostic importance of complement activation. Furthermore, patients with atrial...

  20. Complement component 3 (C3)

    Science.gov (United States)

    ... certain protein. This protein is part of the complement system. The complement system is a group of proteins that move freely ... a role in the development of inflammation. The complement system protects the body from infections, dead cells and ...

  1. 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

  2. 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.

  3. Symmetric Complementation. Revision

    Science.gov (United States)

    1981-01-01

    has efficient decision algorithms if the machine is both space and complementation bounded. Michael Sipser has also suggested an equivalent machine...Vassos Hadzilacos, Joe Halpern, Harry Lewis, A. Prasad, Michael Sipser , and Paul Spirakis for a careful reading and many useful comnents on

  4. A vital role for complement in heart disease.

    Science.gov (United States)

    Lappegård, Knut T; Garred, Peter; Jonasson, Lena; Espevik, Terje; Aukrust, Pål; Yndestad, Arne; Mollnes, Tom E; Hovland, Anders

    2014-10-01

    Heart diseases are common and significant contributors to worldwide mortality and morbidity. During recent years complement mediated inflammation has been shown to be an important player in a variety of heart diseases. Despite some negative results from clinical trials using complement inhibitors, emerging evidence points to an association between the complement system and heart diseases. Thus, complement seems to be important in coronary heart disease as well as in heart failure, where several studies underscore the prognostic importance of complement activation. Furthermore, patients with atrial fibrillation often share risk factors both with coronary heart disease and heart failure, and there is some evidence implicating complement activation in atrial fibrillation. Moreover, Chagas heart disease, a protozoal infection, is an important cause of heart failure in Latin America, and the complement system is crucial for the protozoa-host interaction. Thus, complement activation appears to be involved in the pathophysiology of a diverse range of cardiac conditions. Determination of the exact role of complement in the various heart diseases will hopefully help to identify patients that might benefit from therapeutic complement intervention. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. The complement system in systemic lupus erythematosus: an update.

    Science.gov (United States)

    Leffler, Jonatan; Bengtsson, Anders A; Blom, Anna M

    2014-09-01

    The complement system plays a major role in the autoimmune disease, systemic lupus erythematosus (SLE). However, the role of complement in SLE is complex since it may both prevent and exacerbate the disease. In this review, we explore the latest findings in complement-focused research in SLE. C1q deficiency is the strongest genetic risk factor for SLE, although such deficiency is very rare. Various recently discovered genetic associations include mutations in the complement receptors 2 and 3 as well as complement inhibitors, the latter related to earlier onset of nephritis. Further, autoantibodies are a distinct feature of SLE that are produced as the result of an adaptive immune response and how complement can affect that response is also being reviewed. SLE generates numerous disease manifestations involving contributions from complement such as glomerulonephritis and the increased risk of thrombosis. Furthermore, since most of the complement system is present in plasma, complement is very accessible and may be suitable as biomarker for diagnosis or monitoring of disease activity. This review highlights the many roles of complement for SLE pathogenesis and how research has progressed during recent years. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  6. Complementing the sugar code: role of GAGs and sialic acid in complement regulation

    Directory of Open Access Journals (Sweden)

    Alex eLangford-Smith

    2015-02-01

    Full Text Available Sugar molecules play a vital role on both microbial and mammalian cells, where they are involved in cellular communication, govern microbial virulence and modulate host immunity and inflammatory responses. The complement cascade, as part of a host’s innate immune system, is a potent weapon against invading bacteria but has to be tightly regulated to prevent inappropriate attack and damage to host tissues. A number of complement regulators, such as factor H and properdin, interact with sugar molecules, such as glycosaminoglycans and sialic acid, on host and pathogen membranes and direct the appropriate complement response by either promoting the binding of complement activators or inhibitors. The binding of these complement regulators to sugar molecules can vary from location to location, due to their different specificities and because distinct structural and functional subpopulations of sugars are found in different human organs, such as the brain, kidney and eye. This review will cover recent studies that have provided important new insights into the role of glycosaminoglycans and sialic acid in complement regulation and how sugar recognition may be compromised in disease

  7. Complement activation and regulation in preeclamptic placenta

    Directory of Open Access Journals (Sweden)

    A. Inkeri eLokki

    2014-07-01

    Full Text Available Preeclampsia (PE is a common disorder of pregnancy originating in the placenta. We examined whether excessive activation or poor regulation of the complement system at the maternal-fetal interface could contribute to the development of PE. Location and occurrence of complement components and regulators in placentae were analyzed. Cryostat sections of placentae were processed from 7 early-onset PE (diagnosis <34 weeks of gestation, 5 late-onset PE and 10 control pregnancies and immunostained for 6 complement activators and 6 inhibitors. Fluorescence was quantified and compared between PE and control placentae. Gene copy numbers of complement components C4A and C4B were assessed by a quantitative PCR method. Maternal C4 deficiencies (≥1 missing or non-functional C4 were most common in the early-onset PE group (71%, and more frequent in late-onset PE compared to healthy controls (60% vs. 38%. Complement C1q deposition differed significantly between control and patient groups: controls and early-onset PE patients had more C1q than late-onset PE patients (mean p=0.01 and p=0.005, respectively. C3 activation was analyzed by staining for C3b/iC3b and C3d. C3d was mostly specific to the basal syncytium and C3b/iC3b diffuse in other structures, but there were no clear differences between the study groups. Activated C4 and membrane-bound regulators CD55, CD46 and CD59 were observed abundantly in the syncytiotrophoblast. Syncytial knots, structures enriched in PE, stained specifically for the classical pathway inhibitor C4bp, whereas the key regulator alternative pathway, Factor H showed a wider distribution in the placenta. Differences in C1q deposition between late- and early-onset PE groups may be indicative of the different aetiology of PE symptoms in these patients. Irregular distribution of the complement regulators C4bp and FH in the PE placenta and a higher frequency of C4A deficiencies suggest a disturbed balance between complement activation

  8. Material properties in complement activation

    DEFF Research Database (Denmark)

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

    2011-01-01

    Uncontrolled complement activation can induce many inflammatory and life threatening conditions. Accordingly, the role of complement in initiation of adverse reactions to polymers and nanoparticulate drug carriers is receiving increasing attention and has prompted extensive ‘structure-immune perf......Uncontrolled complement activation can induce many inflammatory and life threatening conditions. Accordingly, the role of complement in initiation of adverse reactions to polymers and nanoparticulate drug carriers is receiving increasing attention and has prompted extensive ‘structure...

  9. Down-regulation of human complement factor H sensitizes non-small cell lung cancer cells to complement attack and reduces in vivo tumor growth.

    Science.gov (United States)

    Ajona, Daniel; Hsu, Yi-Fan; Corrales, Leticia; Montuenga, Luis M; Pio, Ruben

    2007-05-01

    Malignant cells are often resistant to complement activation through the enhanced expression of complement inhibitors. In this work, we examined the protective role of factor H, CD46, CD55, and CD59 in two non-small cell lung cancer cell lines, H1264 and A549, upon activation of the classical pathway of complement. Complement was activated with polyclonal Abs raised against each cell line. After blocking factor H activity with a neutralizing Ab, C3 deposition and C5a release were more efficient. Besides, a combined inhibition of factor H and CD59 significantly increased complement-mediated lysis. CD46 and CD55 did not show any effect in the control of complement activation. Factor H expression was knockdown on A549 cells using small interfering RNA. In vivo growth of factor H-deficient cells in athymic mice was significantly reduced. C3 immunocytochemistry on explanted xenografts showed an enhanced activation of complement in these cells. Besides, when mice were depleted of complement with cobra venom factor, growth was recovered, providing further evidence that complement was important in the reduction of in vivo growth. In conclusion, we show that expression of the complement inhibitor factor H by lung cancer cells can prevent complement activation and improve tumor development in vivo. This may have important consequences in the efficiency of complement-mediated immunotherapies.

  10. Complement: A primer for the coming therapeutic revolution.

    Science.gov (United States)

    Barnum, Scott R

    2017-04-01

    The complement system is an important part of the innate and adaptive immune systems. Originally characterized as a single serum component contributing to the killing of bacteria, we now know that there are close to sixty complement proteins, multiple activation pathways and a wide range of effector functions mediated by complement. The system plays a critical role in host defense against bacteria, viruses, fungi and other pathogens. However, inappropriate complement activation contributes to the pathophysiology of autoimmune diseases and many inflammatory syndromes. Over the last several decades, therapeutic approaches to inhibit complement activation at various steps in the pathways have met with initial success, particularly at the level of the terminal pathway. This success, combined with insight from animal model studies, has lead to an unprecedented effort by biotech and pharmaceutical companies to begin developing complement inhibitors. As a result, complement has been brought for the first time to the attention of pharmacologists, toxicologists, project managers and others in the drug development industry, as well as those in the investment world. The purpose of this primer is to provide a broad overview of complement immunobiology to help those new to complement understand the rationale behind the current therapeutic directions and the investment potential of these new therapeutics. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Complementing Gender Analysis Methods.

    Science.gov (United States)

    Kumar, Anant

    2016-01-01

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

  12. Complement system in lung disease.

    Science.gov (United States)

    Pandya, Pankita H; Wilkes, David S

    2014-10-01

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

  13. Genetics Home Reference: complement component 8 deficiency

    Science.gov (United States)

    ... of the body's immune response known as the complement system . The complement system is a group of proteins that work together ... complement component 8 deficiency Merck Manual Consumer Version: Complement System Orphanet: Immunodeficiency due to a late component of ...

  14. The renaissance of complement therapeutics.

    Science.gov (United States)

    Ricklin, Daniel; Mastellos, Dimitrios C; Reis, Edimara S; Lambris, John D

    2018-01-01

    The increasing number of clinical conditions that involve a pathological contribution from the complement system - many of which affect the kidneys - has spurred a regained interest in therapeutic options to modulate this host defence pathway. Molecular insight, technological advances, and the first decade of clinical experience with the complement-specific drug eculizumab, have contributed to a growing confidence in therapeutic complement inhibition. More than 20 candidate drugs that target various stages of the complement cascade are currently being evaluated in clinical trials, and additional agents are in preclinical development. Such diversity is clearly needed in view of the complex and distinct involvement of complement in a wide range of clinical conditions, including rare kidney disorders, transplant rejection and haemodialysis-induced inflammation. The existing drugs cannot be applied to all complement-driven diseases, and each indication has to be assessed individually. Alongside considerations concerning optimal points of intervention and economic factors, patient stratification will become essential to identify the best complement-specific therapy for each individual patient. This Review provides an overview of the therapeutic concepts, targets and candidate drugs, summarizes insights from clinical trials, and reflects on existing challenges for the development of complement therapeutics for kidney diseases and beyond.

  15. 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.

  16. The renaissance of complement therapeutics

    Science.gov (United States)

    Ricklin, Daniel; Mastellos, Dimitrios C.; Reis, Edimara S.; Lambris, John D.

    2018-01-01

    The increasing number of clinical conditions that involve a pathological contribution from the complement system — many of which affect the kidneys — has spurred a regained interest in therapeutic options to modulate this host defence pathway. Molecular insight, technological advances, and the first decade of clinical experience with the complement-specific drug eculizumab, have contributed to a growing confidence in therapeutic complement inhibition. More than 20 candidate drugs that target various stages of the complement cascade are currently being evaluated in clinical trials, and additional agents are in preclinical development. Such diversity is clearly needed in view of the complex and distinct involvement of complement in a wide range of clinical conditions, including rare kidney disorders, transplant rejection and haemodialysis-induced inflammation. The existing drugs cannot be applied to all complement-driven diseases, and each indication has to be assessed individually. Alongside considerations concerning optimal points of intervention and economic factors, patient stratification will become essential to identify the best complement-specific therapy for each individual patient. This Review provides an overview of the therapeutic concepts, targets and candidate drugs, summarizes insights from clinical trials, and reflects on existing challenges for the development of complement therapeutics for kidney diseases and beyond. PMID:29199277

  17. Complement involvement in periodontitis: molecular mechanisms and rational therapeutic approaches

    Science.gov (United States)

    Hajishengallis, George; Maekawa, Tomoki; Abe, Toshiharu; Hajishengallis, Evlambia; Lambris, John D.

    2015-01-01

    The complement system is a network of interacting fluid-phase and cell surface-associated molecules that trigger, amplify, and regulate immune and inflammatory signaling pathways. Dysregulation of this finely balanced network can destabilize host-microbe homeostasis and cause inflammatory tissue damage. Evidence from clinical and animal model-based studies suggests that complement is implicated in the pathogenesis of periodontitis, a polymicrobial community-induced chronic inflammatory disease that destroys the tooth-supporting tissues. This review discusses molecular mechanisms of complement involvement in the dysbiotic transformation of the periodontal microbiome and the resulting destructive inflammation, culminating in loss of periodontal bone support. These mechanistic studies have additionally identified potential therapeutic targets. In this regard, interventional studies in preclinical models have provided proof-of-concept for using complement inhibitors for the treatment of human periodontitis. PMID:26306443

  18. Cyclosporine Induces Endothelial Cell Release of Complement-Activating Microparticles

    Science.gov (United States)

    Renner, Brandon; Klawitter, Jelena; Goldberg, Ryan; McCullough, James W.; Ferreira, Viviana P.; Cooper, James E.; Christians, Uwe

    2013-01-01

    Defective control of the alternative pathway of complement is an important risk factor for several renal diseases, including atypical hemolytic uremic syndrome. Infections, drugs, pregnancy, and hemodynamic insults can trigger episodes of atypical hemolytic uremic syndrome in susceptible patients. Although the mechanisms linking these clinical events with disease flares are unknown, recent work has revealed that each of these clinical conditions causes cells to release microparticles. We hypothesized that microparticles released from injured endothelial cells promote intrarenal complement activation. Calcineurin inhibitors cause vascular and renal injury and can trigger hemolytic uremic syndrome. Here, we show that endothelial cells exposed to cyclosporine in vitro and in vivo release microparticles that activate the alternative pathway of complement. Cyclosporine-induced microparticles caused injury to bystander endothelial cells and are associated with complement-mediated injury of the kidneys and vasculature in cyclosporine-treated mice. Cyclosporine-induced microparticles did not bind factor H, an alternative pathway regulatory protein present in plasma, explaining their complement-activating phenotype. Finally, we found that in renal transplant patients, the number of endothelial microparticles in plasma increases 2 weeks after starting tacrolimus, and treatment with tacrolimus associated with increased C3 deposition on endothelial microparticles in the plasma of some patients. These results suggest that injury-associated release of endothelial microparticles is an important mechanism by which systemic insults trigger intravascular complement activation and complement-dependent renal diseases. PMID:24092930

  19. Structural basis for therapeutic inhibition of complement C5.

    Science.gov (United States)

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

    2016-05-01

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

  20. Interpain A, a cysteine proteinase from Prevotella intermedia, inhibits complement by degrading complement factor C3.

    Directory of Open Access Journals (Sweden)

    Michal Potempa

    2009-02-01

    Full Text Available Periodontitis is an inflammatory disease of the supporting structures of the teeth caused by, among other pathogens, Prevotella intermedia. Many strains of P. intermedia are resistant to killing by the human complement system, which is present at up to 70% of serum concentration in gingival crevicular fluid. Incubation of human serum with recombinant cysteine protease of P. intermedia (interpain A resulted in a drastic decrease in bactericidal activity of the serum. Furthermore, a clinical strain 59 expressing interpain A was more serum-resistant than another clinical strain 57, which did not express interpain A, as determined by Western blotting. Moreover, in the presence of the cysteine protease inhibitor E64, the killing of strain 59 by human serum was enhanced. Importantly, we found that the majority of P. intermedia strains isolated from chronic and aggressive periodontitis carry and express the interpain A gene. The protective effect of interpain A against serum bactericidal activity was found to be attributable to its ability to inhibit all three complement pathways through the efficient degradation of the alpha-chain of C3 -- the major complement factor common to all three pathways. P. intermedia has been known to co-aggregate with P. gingivalis, which produce gingipains to efficiently degrade complement factors. Here, interpain A was found to have a synergistic effect with gingipains on complement degradation. In addition, interpain A was able to activate the C1 complex in serum, causing deposition of C1q on inert and bacterial surfaces, which may be important at initial stages of infection when local inflammatory reaction may be beneficial for a pathogen. Taken together, the newly characterized interpain A proteinase appears to be an important virulence factor of P. intermedia.

  1. Overview of Laboratory Testing and Clinical Presentations of Complement Deficiencies and Dysregulation.

    Science.gov (United States)

    Frazer-Abel, A; Sepiashvili, L; Mbughuni, M M; Willrich, M A V

    Historically, complement disorders have been attributed to immunodeficiency associated with severe or frequent infection. More recently, however, complement has been recognized for its role in inflammation, autoimmune disorders, and vision loss. This paradigm shift requires a fundamental change in how complement testing is performed and interpreted. Here, we provide an overview of the complement pathways and summarize recent literature related to hereditary and acquired angioedema, infectious diseases, autoimmunity, and age-related macular degeneration. The impact of complement dysregulation in atypical hemolytic uremic syndrome, paroxysmal nocturnal hemoglobinuria, and C3 glomerulopathies is also described. The advent of therapeutics such as eculizumab and other complement inhibitors has driven the need to more fully understand complement to facilitate diagnosis and monitoring. In this report, we review analytical methods and discuss challenges for the clinical laboratory in measuring this complex biochemical system. © 2016 Elsevier Inc. All rights reserved.

  2. Genetics Home Reference: complement component 2 deficiency

    Science.gov (United States)

    ... of the body's immune response known as the complement system . The complement system is a group of proteins that work together ... in the pathway that turns on (activates) the complement system when foreign invaders, such as bacteria, are detected. ...

  3. The role of complement in ocular pathology

    OpenAIRE

    Bora, Nalini S.; Jha, Purushottam; Bora, Puran S.

    2008-01-01

    Functionally active complement system and complement regulatory proteins are present in the normal human and rodent eye. Complement activation and its regulation by ocular complement regulatory proteins contribute to the pathology of various ocular diseases including keratitis, uveitis and age-related macular degeneration. Furthermore, a strong relationship between age-related macular degeneration and polymorphism in the genes of certain complement components/complement regulatory proteins is...

  4. The pivotal role of the mentor in triggering the research on Complement system.

    Science.gov (United States)

    Castellano, Giuseppe

    2015-11-01

    Despite the fact that was one of the first systems to be discovered and investigated in the innate immunity, Complement is continuing to receive growing attention by the scientific community. Complement is involved in several diseases such as diabetes, atherosclerosis or Systemic Lupus Erythematous. Successful therapeutic intervention in treating Complement-mediated diseases such as Hemolytic Uremic Syndrome represent a promising advance to continue the research on Complement to develop specific inhibitors for treating human diseases. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Force Dynamics of Verb Complementation

    Directory of Open Access Journals (Sweden)

    Jacek Woźny

    2015-12-01

    Full Text Available Force Dynamics of Verb Complementation The concepts of motion and force are both extensively discussed in cognitive linguistics literature. But they are discussed separately. The first usually in the context of ‘motion situations’ (Talmy, Slobin, Zlatev, the other as part of the Force Dynamics framework, which was developed by Talmy. The aim of this paper is twofold: first, to argue that the concepts of force and motion should not be isolated but considered as two inseparable parts of force-motion events. The second goal is to prove that the modified Force Dynamics (force-motion framework can be used for precise characterization of the verb complementation patterns. To this end, a random sample of 50 sentences containing the verb ‘went’ is analyzed, demonstrating the differences between the categories of intensive and intransitive complementation with respect to the linguistically coded parameters of force and motion.

  6. 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...

  7. The lectin pathway of complement

    DEFF Research Database (Denmark)

    Ballegaard, Vibe Cecilie Diederich; Haugaard, Anna Karen; Garred, P

    2014-01-01

    The pattern recognition molecules of the lectin complement pathway are important components of the innate immune system with known functions in host-virus interactions. This paper summarizes current knowledge of how these intriguing molecules, including mannose-binding lectin (MBL), Ficolin-1, -2...

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

    Science.gov (United States)

    Tanaka, Gabriela D; Pidde-Queiroz, Giselle; de Fátima D Furtado, Maria; van den Berg, Carmen; Tambourgi, Denise V

    2012-01-16

    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. 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. 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.

  9. Complement factor H in host defense and immune evasion.

    Science.gov (United States)

    Parente, Raffaella; Clark, Simon J; Inforzato, Antonio; Day, Anthony J

    2017-05-01

    Complement is the major humoral component of the innate immune system. It recognizes pathogen- and damage-associated molecular patterns, and initiates the immune response in coordination with innate and adaptive immunity. When activated, the complement system unleashes powerful cytotoxic and inflammatory mechanisms, and thus its tight control is crucial to prevent damage to host tissues and allow restoration of immune homeostasis. Factor H is the major soluble inhibitor of complement, where its binding to self markers (i.e., particular glycan structures) prevents complement activation and amplification on host surfaces. Not surprisingly, mutations and polymorphisms that affect recognition of self by factor H are associated with diseases of complement dysregulation, such as age-related macular degeneration and atypical haemolytic uremic syndrome. In addition, pathogens (i.e., non-self) and cancer cells (i.e., altered-self) can hijack factor H to evade the immune response. Here we review recent (and not so recent) literature on the structure and function of factor H, including the emerging roles of this protein in the pathophysiology of infectious diseases and cancer.

  10. Staphylococcal Proteases Aid in Evasion of the Human Complement System

    DEFF Research Database (Denmark)

    Jusko, Monika; Potempa, Jan; Kantyka, Tomasz

    2014-01-01

    Staphylococcus aureus is an opportunistic pathogen that presents severe health care concerns due to the prevalence of multiple antibiotic-resistant strains. New treatment strategies are urgently needed, which requires an understanding of disease causation mechanisms. Complement is one of the firs...... to be more efficiently killed in human blood. Taken together, the major proteases of S. aureus appear to be important for pathogen-mediated evasion of the human complement system. © 2013 S. Karger AG, Basel.......Staphylococcus aureus is an opportunistic pathogen that presents severe health care concerns due to the prevalence of multiple antibiotic-resistant strains. New treatment strategies are urgently needed, which requires an understanding of disease causation mechanisms. Complement is one of the first...... lines of defense against bacterial pathogens, and S. aureus expresses several specific complement inhibitors. The effect of extracellular proteases from this bacterium on complement, however, has been the subject of limited investigation, except for a recent report regarding cleavage of the C3 component...

  11. Coagulation and complement system in critically ill patients.

    Science.gov (United States)

    Helling, H; Stephan, B; Pindur, G

    2015-01-01

    Activation of coagulation and inflammatory response including the complement system play a major role in the pathogenesis of critical illness. However, only limited data are available addressing the relationship of both pathways and its assessment of a predictive value for the clinical outcome in intense care medicine. Therefore, parameters of the coagulation and complement system were studied in patients with septicaemia and multiple trauma regarded as being exemplary for critical illness. 34 patients (mean age: 51.38 years (±16.57), 15 females, 19 males) were investigated at day 1 of admittance to the intensive care unit (ICU). Leukocytes, complement factors C3a and C5a were significantly (p complement system as part of the inflammatory response is a significant mechanism in septicaemia, whereas loss and consumption of blood components including parts of the coagulation and complement system is more characteristic for multiple trauma. Protein C in case of severe reduction might be of special concern for surviving in sepsis. Activation of haemostasis was occurring in both diseases, however, overt DIC was not confirmed in this study to be a leading mechanism in critically ill patients. MOF score, lactate, C1-inhibitor and prothrombin time have been the only statistically significant predictors for lethal outcome suggesting that organ function, microcirculation, haemostasis and inflammatory response are essential elements of the pathomechanism and clinical course of diseases among critically ill patients.

  12. 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.

  13. The Complement System and Ocular Diseases

    OpenAIRE

    Jha, Purushottam; Bora, Puran S.; Bora, Nalini S.

    2007-01-01

    In the normal eye, the complement system is continuously activated at low levels and both membrane-bound and soluble intraocular complement regulatory proteins tightly regulate this spontaneous complement activation. This allows protection against pathogens without causing any damage to self-tissue and vision loss. The complement system and complement regulatory proteins control the intraocular inflammation in autoimmune uveitis and play an important role in the development of corneal inflamm...

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

    Science.gov (United States)

    Loeffler, David A; Camp, Dianne M; Bennett, David A

    2008-01-01

    Bielschowsky-stained plaque counts, quantitative assessment of the extent to which complement activation may mediate the relationship between plaques and cognitive function could not be performed. Additional studies with animal models of AD (if late-stage complement activation can be demonstrated), or possibly a trial in AD patients with an inhibitor of late-stage complement activation, may be necessary to determine the significance of this process in AD. PMID:18334032

  15. Complement in clinical medicine: Clinical trials, case reports and therapy monitoring.

    Science.gov (United States)

    Ricklin, Daniel; Barratt-Due, Andreas; Mollnes, Tom Eirik

    2017-09-01

    Research during past decades made it evident that complement is involved in more tasks than fighting infections, but has important roles in other immune surveillance and housekeeping functions. If the balance between complement activation and regulation is out of tune, however, complement can quickly turn against the host and contribute to adverse processes that result in various clinical conditions. Whereas clinical awareness was initially focused on complement deficiencies, excessive activation and insufficient regulation are frequently the dominant factors in complement-related disorders. The individual complement profile of a patient often determines the course and severity of the disease, and the pathophysiological involvement of complement may be highly diverse. As a consequence, complement assays have evolved as essential tools not only in initial diagnosis but also for following disease progression and for monitoring complement-targeted therapies, which become increasingly available in routine clinical use. We herein review the current state of complement-directed drug candidates in clinical evaluation and provide an overview of extended indications considered for the FDA-approved inhibitor eculizumab. Furthermore we review the literature describing cases reports and case series where eculizumab has been used "off-label". Finally, we give a summary of the currently available tests to measure complement profiles and discuss their suitability in diagnostics and treatment monitoring. With complement finally entering the clinical arena, there are intriguing opportunities for treating complement-mediated diseases. However, this progress also requires a new awareness about complement pathophysiology, adequate diagnostic tools and suitable treatment options among clinicians treating patients with such disorders. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  16. Complement genetics and host defence.

    Science.gov (United States)

    Lachmann, P J

    1990-12-01

    There is a surprisingly high frequency of allelic variation in complement proteins. The best candidate for a true selective polymorphism is that of C3. For C4 and factor B within the MHC it is more difficult to identify the effects of individual alleles. No evidence suggests other alleles of C4 (and C2) than the null alleles (or the two isoproteins C4A and C4B) to have any functional differences with resistance. Thus, the major functions of complement, as shown by the effects of deficiency, are to resist infection against bacteria and particularly against Neisseria, and to prevent immune complex disease. There are also undoubtedly balancing contributions to the pathogenesis of some infections and to all immune complex disease. Data from studies of C4 polymorphism and from the presence of control proteins on micro-organisms suggest there may be in addition more subtle contributions to immunity against a variety of other infections.

  17. 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.

  18. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. HIV Coinfection Enhances Complement Activation During Sepsis

    NARCIS (Netherlands)

    Huson, Michaëla A. M.; Wouters, Diana; van Mierlo, Gerard; Grobusch, Martin P.; Zeerleder, Sacha S.; van der Poll, Tom

    2015-01-01

    Human immunodeficiency virus (HIV)-induced complement activation may play a role in chronic immune activation in patients with HIV infection and influence the complement system during acute illness. We determined the impact of HIV infection on the complement system in patients with asymptomatic HIV

  20. 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

  1. Regulation of mast cell activation by complement-derived peptides.

    Science.gov (United States)

    Erdei, Anna; Andrásfalvy, Márton; Péterfy, Hajna; Tóth, Gábor; Pecht, Israel

    2004-03-29

    It is known for more than 25 years that the complement-derived anaphylatoxic peptides, C3a, C4a and C5a are potent activators of basophils and certain types of mast cells. Although tissue distribution of receptors for C3a and C5a well exceeds myeloid cells, apparently they are not expressed on mucosal type mast cells, consequently these cells are not activated by C3a and C5a. Our results do however demonstrate that C3a and peptides related to this complement activation product are able to inhibit FcRI-clustering induced activation of mucosal type mast cells-such as RBL-2H3 cells and bone-marrow derived mast cells. Based on the current results we propose the presence of separate "activator" and "inhibitor" sequence motifs in C3a which are in balance under physiologic conditions.

  2. The role of the complement system in hereditary angioedema.

    Science.gov (United States)

    Csuka, Dorottya; Veszeli, Nóra; Varga, Lilian; Prohászka, Zoltán; Farkas, Henriette

    2017-09-01

    Hereditary angioedema (HAE) is a rare, but potentially life-threatening disorder, characterized by acute, recurring, and self-limiting edematous episodes of the face, extremities, trunk, genitals, upper airways, or the gastrointestinal tract. HAE may be caused by the deficiency of C1-inhibitor (C1-INH-HAE) but another type of the disease, hereditary angioedema with normal C1-INH function (nC1-INH-HAE) was also described. The patient population is quite heterogeneous as regards the location, frequency, and severity of edematous attacks, presenting large intra- and inter-individual variation. Here, we review the role of the complement system in the pathomechanism of HAE and also present an overview on the complement parameters having an importance in the diagnosis or in predicting the severity of HAE. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Complement therapeutics in inflammatory diseases: promising drug candidates for C3-targeted intervention.

    Science.gov (United States)

    Mastellos, D C; Ricklin, D; Hajishengallis, E; Hajishengallis, G; Lambris, J D

    2016-02-01

    There is increasing appreciation that complement dysregulation lies at the heart of numerous immune-mediated and inflammatory disorders. Complement inhibitors are therefore being evaluated as new therapeutic options in various clinical translation programs and the first clinically approved complement-targeted drugs have profoundly impacted the management of certain complement-mediated diseases. Among the many members of the intricate protein network of complement, the central component C3 represents a 'hot-spot' for complement-targeted therapeutic intervention. C3 modulates both innate and adaptive immune responses and is linked to diverse immunomodulatory systems and biological processes that affect human pathophysiology. Compelling evidence from preclinical disease models has shown that C3 interception may offer multiple benefits over existing therapies or even reveal novel therapeutic avenues in disorders that are not commonly regarded as complement-driven, such as periodontal disease. Using the clinically developed compstatin family of C3 inhibitors and periodontitis as illustrative examples, this review highlights emerging therapeutic concepts and developments in the design of C3-targeted drug candidates as novel immunotherapeutics for oral and systemic inflammatory diseases. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. On the value of therapeutic interventions targeting the complement system in acute myocardial infarction.

    Science.gov (United States)

    Emmens, Reindert W; Wouters, Diana; Zeerleder, Sacha; van Ham, S Marieke; Niessen, Hans W M; Krijnen, Paul A J

    2017-04-01

    The complement system plays an important role in the inflammatory response subsequent to acute myocardial infarction (AMI). The aim of this study is to create a systematic overview of studies that have investigated therapeutic administration of complement inhibitors in both AMI animal models and human clinical trials. To enable extrapolation of observations from included animal studies toward post-AMI clinical trials, ex vivo studies on isolated hearts and proof-of-principle studies on inhibitor administration before experimental AMI induction were excluded. Positive therapeutic effects in AMI animal models have been described for cobra venom factor, soluble complement receptor 1, C1-esterase inhibitor (C1-inh), FUT-175, C1s-inhibitor, anti-C5, ADC-1004, clusterin, and glycosaminoglycans. Two types of complement inhibitors have been tested in clinical trials, being C1-inh and anti-C5. Pexelizumab (anti-C5) did not result in reproducible beneficial effects for AMI patients. Beneficial effects were reported in AMI patients for C1-inhibitor, albeit in small patient groups. In general, despite the absence of consistent positive effects in clinical trials thus far, the complement system remains a potentially interesting target for therapy in AMI patients. Based on the study designs of previous animal studies and clinical trials, we discuss several issues which require attention in the design of future studies: adjustment of clinical trial design to precise mechanism of action of administered inhibitor, optimizing the duration of therapy, and optimization of time point(s) on which therapeutic effects will be evaluated. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Effects of freezer storage time on levels of complement biomarkers.

    Science.gov (United States)

    Morgan, Angharad R; O'Hagan, Caroline; Touchard, Samuel; Lovestone, Simon; Paul Morgan, B

    2017-11-06

    There is uncertainty regarding how stable complement analytes are during long-term storage at - 80 °C. As part of our work program we have measured 17 complement biomarkers (C1q, C1 inhibitor, C3, C3a, iC3b, C4, C5, C9, FB, FD, FH, FI, TCC, Bb, sCR1, sCR2, Clusterin) and the benchmark inflammatory marker C-reactive protein (CRP) in a large set of plasma samples (n = 720) that had been collected, processed and subsequently stored at - 80 °C over a period of 6.6-10.6 years, prior to laboratory analysis. The biomarkers were measured using solid-phase enzyme immunoassays with a combination of multiplex assays using the MesoScale Discovery Platform and single-plex enzyme-linked immunosorbent assays (ELISAs). As part of a post hoc analysis of extrinsic factors (co-variables) affecting the analyses we investigated the impact of freezer storage time on the values obtained for each complement analyte. With the exception of five analytes (C4, C9, sCR2, clusterin and CRP), storage time was significantly correlated with measured plasma concentrations. For ten analytes: C3, FI, FB, FD, C5, sCR1, C3a, iC3b, Bb and TCC, storage time was positively correlated with concentration and for three analytes: FH, C1q, and C1 inhibitor, storage time was negatively correlated with concentration. The results suggest that information on storage time should be regarded as an important co-variable and taken into consideration when analysing data to look for associations of complement biomarker levels and disease or other outcomes.

  7. The complement system in age-related macular degeneration: A review of rare genetic variants and implications for personalized treatment.

    Science.gov (United States)

    Geerlings, Maartje J; de Jong, Eiko K; den Hollander, Anneke I

    2017-04-01

    Age-related macular degeneration (AMD) is a progressive retinal disease and the major cause of irreversible vision loss in the elderly. Numerous studies have found both common and rare genetic variants in the complement pathway to play a role in the pathogenesis of AMD. In this review we provide an overview of rare variants identified in AMD patients, and summarize the functional consequences of rare genetic variation in complement genes on the complement system. Finally, we discuss the relevance of this work in light of ongoing clinical trials that study the effectiveness of complement inhibitors against AMD. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. The Role of Complement in Tumor Growth

    Science.gov (United States)

    Pio, Ruben; Corrales, Leticia; Lambris, John D.

    2015-01-01

    Complement is a central part of the immune system that has developed as a first defense against non-self cells. Neoplastic transformation is accompanied by an increased capacity of the malignant cells to activate complement. In fact, clinical data demonstrate complement activation in cancer patients. On the basis of the use of protective mechanisms by malignant cells, complement activation has traditionally been considered part of the body's immunosurveillance against cancer. Inhibitory mechanisms of complement activation allow cancer cells to escape from complement-mediated elimination and hamper the clinical efficacy of monoclonal antibody–based cancer immunotherapies. To overcome this limitation, many strategies have been developed with the goal of improving complement-mediated effector mechanisms. However, significant work in recent years has identified new and surprising roles for complement activation within the tumor microenvironment. Recent reports suggest that complement elements can promote tumor growth in the context of chronic inflammation. This chapter reviews the data describing the role of complement activation in cancer immunity, which offers insights that may aid the development of more effective therapeutic approaches to control cancer. PMID:24272362

  9. 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

  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. 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...... 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...... 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...

  12. Complement pathways and meningococcal disease : diagnostic aspects

    DEFF Research Database (Denmark)

    Sjöholm, A G; Truedsson, L; Jensenius, Jens Christian

    2001-01-01

    Complement is an immunological effector system that bridges innate and acquired immunity in several ways. There is a striking association between susceptibility to meningococcal disease and various forms of complement deficiency (1,2). In defense against bacterial infection, the most important...... function of complement is probably to serve as a mediator of antibody-dependent immunity. Specific antibodies can trigger activation of the classical and the alternative pathways of complement activation (3-5). It is well known that antibody-independent mechanisms interfere with alternative pathway...... activation on the bacterial surface (6,7). The newly discovered mannan-binding lectin (MBL) pathway of complement activation appears to be protective against many types of infection (8) and adds previously unsuspected aspects of innate immunity to complement-mediated defense. Interestingly, immune responses...

  13. Role of Complement in Autoimmune Hemolytic Anemia.

    Science.gov (United States)

    Berentsen, Sigbjørn

    2015-09-01

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

  14. The Lectin Pathway of Complement and Biocompatibility

    DEFF Research Database (Denmark)

    Hein, Estrid; Garred, Peter

    2015-01-01

    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...... 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....

  15. Role of Complement in Autoimmune Hemolytic Anemia

    OpenAIRE

    Berentsen, Sigbj?rn

    2015-01-01

    Summary The classification of autoimmune hemolytic anemias and the complement system are reviewed. In autoimmune hemolytic anemia of the warm antibody type, complement-mediated cell lysis is clinically relevant in a proportion of the patients but is hardly essential for hemolysis in most patients. Cold antibody-mediated autoimmune hemolytic anemias (primary cold agglutinin disease, secondary cold agglutinin syndrome and paroxysmal cold hemoglobinuria) are entirely complement-mediated disorder...

  16. DYNAMICS OF ACTIVITY OF SOME COMPONENTS OF COMPLEMENT IN TREATMENT OF ATOPIC DERMATITIS IN CHILDREN

    Directory of Open Access Journals (Sweden)

    S. S. Andina

    2014-01-01

    Full Text Available The article describes immunoassay methods of determining the functional activity of the components C3 and C9 and C1 inhibitor for diagnostic and prognostic purposes in the treatment of patients. The activity of these components, as well as the activity and the amount of C1 inhibitor in the blood serum of children aged 6 months to 18 years suffering from atopic dermatitis have been analyzed before and after treatment to determine the involvement of the complement system in the pathogenesis of this disease. The developed methods of enzyme immunoassay for determination of the functional components of the complement system have shown high sensitivity and reliability. The activity of C9 component involved in the membrane attack of the complement was significantly below normal in children with atopic dermatitis. That indicates the involvement of membrane attack complex components in the skin necrotic processes. Component C3 activity is also reduced. C3 is the key component of the activation cascade involved in the inflammatory processes. Specific activity of C1 inhibitor increased before and during the treatment, indicating an increased biosynthesis of this acute phase protein. Positive tendency towards the normalization of the status of complement after treatment has been observed. Data obtained in this study indicate the involvement of complement system in the pathological process of atopic dermatitis in children.

  17. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Viral mimicry of the complement system

    Indian Academy of Sciences (India)

    Unknown

    et al 2002), hepatitis C virus (Ishii et al 2001) and HIV. (Ezekowitz et al 1989; Saifuddin et al 2000). Activation of the complement system in the absence of proper regulation can lead to virus neutralization. The various mechanisms which are known to inactivate viruses are: (i) neutralization by complement dependant ...

  19. Viral mimicry of the complement system

    Indian Academy of Sciences (India)

    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 ...

  20. Complement Clause Formation In Leteh | Ansah | Contemporary ...

    African Journals Online (AJOL)

    This paper explores the complementation phenomenon in Leteh. The discussion is done within the framework of Basic Linguistic Theory (Dixon 1997), and further appeals to the theory of grammaticalization to explain the multiple functions of Leteh complementizers. Leteh is a South Guan (Kwa, Niger-Congo) language ...

  1. The complement system in systemic autoimmune disease

    NARCIS (Netherlands)

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

    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. Complementary Roles of the Classical and Lectin Complement Pathways in the Defense against Aspergillus fumigatus

    DEFF Research Database (Denmark)

    Rosbjerg, Anne; Genster, Ninette; Pilely, Katrine

    2016-01-01

    , lectin, and alternative pathways under both immunocompetent and immunocompromised conditions to provide a relevant dual-perspective on the response against A. fumigatus. Conidia (spores) from a clinical isolate of A. fumigatus were combined with various human serum types (including serum deficient...... of various complement components and serum from umbilical cord blood). We also combined this with inhibitors against C1q, mannose-binding lectin (MBL), and ficolin-2 before complement activation products and phagocytosis were detected by flow cytometry. Our results showed that alternative pathway amplified...... complement on A. fumigatus, but required classical and/or lectin pathway for initiation. In normal human serum, this initiation came primarily from the classical pathway. However, with a dysfunctional classical pathway (C1q-deficient serum), lectin pathway activated complement and mediated opsonophagocytosis...

  3. 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...

  4. Structural insight into proteolytic activation and regulation of the complement system.

    Science.gov (United States)

    Schatz-Jakobsen, Janus A; Pedersen, Dennis V; Andersen, Gregers R

    2016-11-01

    The complement system is a highly complex and carefully regulated proteolytic cascade activated through three different pathways depending on the activator recognized. The structural knowledge regarding the intricate proteolytic enzymes that activate and control complement has increased dramatically over the last decade. This development has been pivotal for understanding how mutations within complement proteins might contribute to pathogenesis and has spurred new strategies for development of complement therapeutics. Here we describe and discuss the complement system from a structural perspective and integrate the most recent findings obtained by crystallography, small-angle X-ray scattering, and electron microscopy. In particular, we focus on the proteolytic enzymes governing activation and their products carrying the biological effector functions. Additionally, we present the structural basis for some of the best known complement inhibitors. The large number of accumulated molecular structures enables us to visualize the relative size, position, and overall orientation of many of the most interesting complement proteins and assembled complexes on activator surfaces and in membranes. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. GLUCOCORTICOSTEROIDS' EFFECT UPON THE COMPLEMENT LEVEL

    Directory of Open Access Journals (Sweden)

    Voja Pavlovic

    2001-03-01

    Full Text Available The effect of high doses of cortisol upon the level of the overall complements'hemolytic activity and particular complements' components is studies. The experimentsinvolved guinea pigs of male sex of the body mass from 300 to 400 g, namelythose that have not been treated by anything so far. The doses of hydrocortisone(Hemofarm DD were also used for the experiment. The overall complements'activity was determined by testing the capabilities of a series of various solutions ofthe guinea pigs' serum to separate sheep erythrocytes that were made sensitive byrabbit anti-erythrocyte antibodies. The determination of the C1, C2, C3 and C4complements' components was done by the method of the quantitative diffusion ofthe radial type by using the Partigen blocks Behringwerke AG. The series comprised25 guinea pigs of male sex. The low cortisol level rapidly increase the overallhemolytic activity of the complements of the C1 est erase concentration. Along withthe cortisol dose increase the overall hemolytic complements' activity is dropping aswell as that of the C1, C2, C3 and C4 complements' components.

  6. Complement receptors in myeloid cell adhesion and phagocytosis

    OpenAIRE

    Dustin, Michael L.

    2016-01-01

    Myeloid cells make extensive use of the complement system in the context of recruitment, phagocytosis and other effector functions. There are several types of complement receptors on myeloid cells including G-proteins coupled receptors for localizing the source of complement activation, and three sets of type I transmembrane proteins that link complement to phagocytosis-complement receptor 1, a single chain type I membrane protein with tandem complement regulatory repeats, complement receptor...

  7. Transnationalism and integration : complements or Substitutes?

    NARCIS (Netherlands)

    Dekker, B.; Siegel, M.

    2013-01-01

    This paper investigates the relationship between transnational practices and integration by testing whether they are substitutes or complements. For this purpose, we use a multidimensional transnationalism index. The index includes three dimensions of transnational practices, including migrants'

  8. 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.

  9. Incomplete inhibition by eculizumab: mechanistic evidence for residual C5 activity during strong complement activation.

    Science.gov (United States)

    Harder, Markus J; Kuhn, Nadine; Schrezenmeier, Hubert; Höchsmann, Britta; von Zabern, Inge; Weinstock, Christof; Simmet, Thomas; Ricklin, Daniel; Lambris, John D; Skerra, Arne; Anliker, Markus; Schmidt, Christoph Q

    2017-02-23

    Eculizumab inhibits the terminal, lytic pathway of complement by blocking the activation of the complement protein C5 and shows remarkable clinical benefits in certain complement-mediated diseases. However, several reports suggest that activation of C5 is not always completely suppressed in patients even under excess of eculizumab over C5, indicating that residual C5 activity may derogate the drug's therapeutic benefit under certain conditions. By using eculizumab and the tick-derived C5 inhibitor coversin, we determined conditions ex vivo in which C5 inhibition is incomplete. The degree of such residual lytic activity depended on the strength of the complement activator and the resulting surface density of the complement activation product C3b, which autoamplifies via the alternative pathway (AP) amplification loop. We show that at high C3b densities required for binding and activation of C5, both inhibitors reduce but do not abolish this interaction. The decrease of C5 binding to C3b clusters in the presence of C5 inhibitors correlated with the levels of residual hemolysis. However, by employing different C5 inhibitors simultaneously, residual hemolytic activity could be abolished. The importance of AP-produced C3b clusters for C5 activation in the presence of eculizumab was corroborated by the finding that residual hemolysis after forceful activation of the classical pathway could be reduced by blocking the AP. By providing insights into C5 activation and inhibition, our study delivers the rationale for the clinically observed phenomenon of residual terminal pathway activity under eculizumab treatment with important implications for anti-C5 therapy in general. © 2017 by The American Society of Hematology.

  10. Complement and Immunoregulation in Tissue Injury

    Science.gov (United States)

    2015-12-01

    transplantation, cardiovascular and autoimmune diseases . The complement system is an important mediator of IR injury in various organs including...on epithelial cells. Because of its ability to mobilize neutrophils, IL-17A is important in the pathogenesis of autoimmune diseases , and in chronic...intestine, kidney , liver, lungs and heart. In mesenteric IR complement activation and deposition have been recognized as key components for the initiation

  11. Polyphosphate suppresses complement via the terminal pathway.

    Science.gov (United States)

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

    2014-01-30

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

  12. 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.

  13. Complement Recognition Pathways in Renal Transplantation.

    Science.gov (United States)

    Nauser, Christopher L; Farrar, Conrad A; Sacks, Steven H

    2017-09-01

    The complement system, consisting of soluble and cell membrane-bound components of the innate immune system, has defined roles in the pathophysiology of renal allograft rejection. Notably, the unavoidable ischemia-reperfusion injury inherent to transplantation is mediated through the terminal complement activation products C5a and C5b-9. Furthermore, biologically active fragments C3a and C5a, produced during complement activation, can modulate both antigen presentation and T cell priming, ultimately leading to allograft rejection. Earlier work identified renal tubule cell synthesis of C3, rather than hepatic synthesis of C3, as the primary source of C3 driving these effects. Recent efforts have focused on identifying the local triggers of complement activation. Collectin-11, a soluble C-type lectin expressed in renal tissue, has been implicated as an important trigger of complement activation in renal tissue. In particular, collectin-11 has been shown to engage L-fucose at sites of ischemic stress, activating the lectin complement pathway and directing the innate immune response to the distressed renal tubule. The interface between collectin-11 and L-fucose, in both the recipient and the allograft, is an attractive target for therapies intended to curtail renal inflammation in the acute phase. Copyright © 2017 by the American Society of Nephrology.

  14. A tick mannose-binding lectin inhibits the vertebrate complement cascade to enhance transmission of the Lyme disease agent

    Science.gov (United States)

    Schuijt, Tim J.; Coumou, Jeroen; Narasimhan, Sukanya; Dai, Jianfeng; DePonte, Kathleen; Wouters, Diana; Brouwer, Mieke; Oei, Anneke; Roelofs, Joris J.T.H.; van Dam, Alje P.; van der Poll, Tom; van ’t Veer, Cornelis; Hovius, Joppe W.; Fikrig, Erol

    2011-01-01

    Summary The Lyme disease agent, Borrelia burgdorferi, is primarily transmitted to vertebrates by Ixodes ticks. The classical and alternative complement pathways are important in Borrelia eradication by the vertebrate host. We recently identified a tick salivary protein, designated P8 that reduced complement-mediated killing of Borrelia. We now discover that P8 interferes with the human lectin complement cascade resulting in impaired neutrophil phagocytosis and chemotaxis, and diminished Borrelia lysis. Therefore, P8 was renamed the lectin complement pathway inhibitor (TSLPI). TSLPI-silenced ticks, or ticks exposed to TSLPI-immune mice, were hampered in Borrelia transmission. Moreover, Borrelia acquisition and persistence in tick midguts was impaired in ticks feeding on TSLPI-immunized B. burgdorferi-infected mice. Together, our findings suggest an essential role for the lectin complement cascade in Borrelia eradication and demonstrate how a vector-borne pathogen co-opts a vector protein to facilitate early mammalian infection and vector colonization. PMID:21843870

  15. 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

  16. Rodent complementation group 8 (ERCC8) corresponds to Cockayne syndrome complementation group A.

    Science.gov (United States)

    Itoh, T; Shiomi, T; Shiomi, N; Harada, Y; Wakasugi, M; Matsunaga, T; Nikaido, O; Friedberg, E C; Yamaizumi, M

    1996-02-15

    US31 is a UV-sensitive mutant cell line (rodent complementation group 8) derived from a mouse T cell line L5178Y. We analyzed removal kinetics for UV-induced cyclobutane pyrimidine dimers and (6-4) photoproducts in US31 cells using monoclonal antibodies against these photoproducts. While nearly all (6-4) photoproducts were repaired within 6 h after UV-irradiation, more than 70% of cyclobutane pyrimidine dimers remained unrepaired even 24 h after UV-irradiation. These kinetics resembled those of Cockayne syndrome (CS) cells. Since US31 cells had a low efficiency of cell fusion and transfection, which hampered both complementation tests and gene cloning, we constructed fibroblastic complementation group 8 cell line 6L1030 by fusion of US31 cells with X-irradiated normal mouse fibroblastic LTA cells. Complementation tests by cell fusion and transfection using 6L1030 cells revealed that rodent complementation group 8 corresponded to CS complementation group A.

  17. Functional Analyses of Complement Convertases Using C3 and C5-Depleted Sera

    Science.gov (United States)

    Okroj, Marcin; Holmquist, Emelie; King, Ben C.; Blom, Anna M.

    2012-01-01

    C3 and C5 convertases are central stages of the complement cascade since they converge the different initiation pathways, augment complement activation by an amplification loop and lead to a common terminal pathway resulting in the formation of the membrane attack complex. Several complement inhibitors attenuate convertase formation and/or accelerate dissociation of convertase complexes. Functional assays used to study these processes are often performed using purified complement components, from which enzymatic complexes are reconstituted on the surface of erythrocytes or artificial matrices. This strategy enables identification of individual interactions between convertase components and putative regulators but carries an inherent risk of detecting non-physiological interactions that would not occur in a milieu of whole serum. Here we describe a novel, alternative method based on C3 or C5-depleted sera, which support activation of the complement cascade up to the desired stages of convertases. This approach allows fast and simple assessment of the influence of putative regulators on convertase formation and stability. As an example of practical utility of the assay, we performed studies on thioredoxin-1 in order to clarify the mechanism of its influence on complement convertases. PMID:23071769

  18. Functional analyses of complement convertases using C3 and C5-depleted sera.

    Directory of Open Access Journals (Sweden)

    Marcin Okroj

    Full Text Available C3 and C5 convertases are central stages of the complement cascade since they converge the different initiation pathways, augment complement activation by an amplification loop and lead to a common terminal pathway resulting in the formation of the membrane attack complex. Several complement inhibitors attenuate convertase formation and/or accelerate dissociation of convertase complexes. Functional assays used to study these processes are often performed using purified complement components, from which enzymatic complexes are reconstituted on the surface of erythrocytes or artificial matrices. This strategy enables identification of individual interactions between convertase components and putative regulators but carries an inherent risk of detecting non-physiological interactions that would not occur in a milieu of whole serum. Here we describe a novel, alternative method based on C3 or C5-depleted sera, which support activation of the complement cascade up to the desired stages of convertases. This approach allows fast and simple assessment of the influence of putative regulators on convertase formation and stability. As an example of practical utility of the assay, we performed studies on thioredoxin-1 in order to clarify the mechanism of its influence on complement convertases.

  19. 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. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  20. Kallikrein Cleaves C3 and Activates Complement.

    Science.gov (United States)

    Irmscher, Sarah; Döring, Nadia; Halder, Luke D; Jo, Emeraldo A H; Kopka, Isabell; Dunker, Christine; Jacobsen, Ilse D; Luo, Shanshan; Slevogt, Hortense; Lorkowski, Stefan; Beyersdorf, Niklas; Zipfel, Peter F; Skerka, Christine

    2017-12-14

    The human plasma contact system is an immune surveillance system activated by the negatively charged surfaces of bacteria and fungi and includes the kallikrein-kinin, the coagulation, and the fibrinolytic systems. Previous work shows that the contact system also activates complement, and that plasma enzymes like kallikrein, plasmin, thrombin, and FXII are involved in the activation process. Here, we show for the first time that kallikrein cleaves the central complement component C3 directly to yield active components C3b and C3a. The cleavage site within C3 is identical to that recognized by the C3 convertase. Also, kallikrein-generated C3b forms C3 convertases, which trigger the C3 amplification loop. Since kallikrein also cleaves factor B to yield Bb and Ba, kallikrein alone can trigger complement activation. Kallikrein-generated C3 convertases are inhibited by factor H; thus, the kallikrein activation pathway merges with the amplification loop of the alternative pathway. Taken together, these data suggest that activation of the contact system locally enhances complement activation on cell surfaces. The human pathogenic microbe Candida albicans activates the contact system in normal human serum. However, C. albicans immediately recruits factor H to the surface, thereby evading the alternative and likely kallikrein-mediated complement pathways. © 2017 S. Karger AG, Basel.

  1. Platelets and the complement cascade in atherosclerosis.

    Science.gov (United States)

    Patzelt, Johannes; Verschoor, Admar; Langer, Harald F

    2015-01-01

    Atherosclerosis and its late sequels are still the number one cause of death in western societies. Platelets are a driving force not only during the genesis of atherosclerosis, but especially in its late stages, as evidenced by complications such as arterial thrombosis, myocardial infarction, and ischemic stroke. Atherosclerosis is increasingly recognized as an inflammatory disease, influenced by various immune mechanisms. The complement system is part of our innate immune system, and its diverse roles in atherosclerosis have become evident over the past years. In this review we identify points of intersection between platelets and the complement system and discuss their relevance for atherosclerosis. Specifically, we will focus on roles for platelets in the onset as well as progression of the disease, a possible dual role for complement in the genesis and development of atherosclerosis, and review emerging literature revealing previously unrecognized cross-talk between platelets and the complement system and discuss its possible impact for atherosclerosis. Finally, we identify limitations of current research approaches and discuss perspectives of complement modulation in the control of the disease.

  2. Excretions/secretions from medicinal larvae (Lucilia sericata) inhibit complement activation by two mechanisms.

    Science.gov (United States)

    Tamura, Tetsuro; Cazander, Gwendolyn; Rooijakkers, Suzan H M; Trouw, Leendert A; Nibbering, Peter H

    2017-01-01

    Larvae of the blowfly Lucilia sericata facilitate wound healing by removing dead tissue and biofilms from non-healing and necrotic wounds. Another beneficial action of larvae and their excretions/secretions (ES) is down-regulation of excessive inflammation. As prolonged complement activation is key to excessive inflammation, the aim of this study was to elucidate the mechanisms underlying the anti-complement activities of ES. Results revealed that heat sensitive serine proteases in ES degrade multiple complement proteins in all steps of the three complement activation pathways. Importantly, C3a and C5a-major activators of inflammation-were also degraded by ES and pretreatment of these factors with ES completely blocked their ability to induce activation of human neutrophils. Pre-exposure of the neutrophils to ES did not affect their responsiveness to C3a/C5a and fMLP, indicating that the receptors for these activators on neutrophils were not affected by ES. Surprisingly, heat and serine protease inhibitor pretreatment did not affect the ability of ES to inhibit C5b-9 complex formation despite degrading complement proteins, indicating a second complement-inhibiting molecule in ES. Heated ES was as effective as intact ES in inhibiting C3 deposition upon activation of the alternative pathway, but was significantly less effective in wells with a classical or lectin pathway-specific coating. Unfortunately, the molecules affecting the complement system could not be identified due to an insufficient database for L. sericata. Together, larval ES inhibit complement activation by two different mechanisms and down-regulate the C3a/C5a-mediated neutrophil activation. This attenuates the inflammatory process, which may facilitate wound healing. © 2016 by the Wound Healing Society.

  3. Three complementation groups in Cockayne syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, A.R. (Sussex Univ., Brighton (UK). M.R.C. Cell Mutation Unit)

    1982-12-01

    After 16 Jm/sup -2/ of UV-irradiation non-dividing normal cells recover normal rates of RNA synthesis within 24 h, whereas in cells from donors with Cockayne syndrome (CS) the rate of RNA synthesis gradually declines. Cultures of a mixed population from 2 CS donors were fused with polyethylene glycol: subsequently they were UV-irradiated and RNA synthesis was measured autoradiographically in mono-, bi-, and multinuclear cells. Genetic complementation was indicated by high levels of RNA synthesis in bi- and multinuclear cells when compared with mononuclear cells. Using this assay, 11 CS strains have been assigned to three complementation groups: 2 into group A, 8 into group B and 1 into group C. The strain in group C is derived from an individual who also had xeroderma pigmentosum (XP), and was the sole known representative of XP-complementation group B.

  4. The Complement System in Lupus Nephritis.

    Science.gov (United States)

    Birmingham, Daniel J; Hebert, Lee A

    2015-09-01

    The complement system is composed of a family of soluble and membrane-bound proteins that historically has been viewed as a key component of the innate immune system, with a primary role of providing a first-line defense against microorganisms. Although this role indeed is important, complement has many other physiological roles, including the following: (1) influencing appropriate immune responses, (2) disposing of waste in the circulation (immune complexes, cellular debris), and (3) contributing to damage of self-tissue through inflammatory pathways. These three roles are believed to be significant factors in the pathogenesis of systemic lupus erythematosus, particularly its renal manifestation (lupus nephritis), contributing both protective and damaging effects. In this review, we provide an overview of the human complement system and its functions, and discuss its intricate and seemingly contradictory roles in the pathogenesis of lupus nephritis. Copyright © 2015. Published by Elsevier Inc.

  5. Novel biological networks modulated by complement.

    Science.gov (United States)

    Mastellos, Dimitrios; Andronis, Christos; Persidis, Andreas; Lambris, John D

    2005-06-01

    The almost complete deciphering of the human genome has paved the way for the application of new technology platforms in understanding the contribution of complex biological pathways to human pathophysiology and disease. In the post-genomic era, the concept of systems biology has gained significant momentum and biomedical research is now being conducted on an integrated and cross-disciplinary platform that pulls together its resources from diverse fields such as computational biology, bioinformatics, functional genomics, structural biology, and proteomics. In this perspective, the identity of established biologic systems is being re-examined in the light of novel findings that suggest novel associations between otherwise unrelated pathways and individual proteins. Complement exemplifies such a system that, transcending its innate immune identity, has forged functional associations with multiple pathways and networks in modulating basic biologic processes. In the present article, we provide a global overview of these unusual system associations of complement with the aid of a powerful and high-throughput bioinformatics platform. Using a novel approach called systems literature analysis that allows the rapid extraction of text-based associations between genes and pathways from the ever expanding scientific article database, we have selected a broad range of biologic processes modulated by complement proteins and have constructed an integrated map of complement-mediated networks that incorporates well over 85 diverse biologic pathways. Expanding the complement cascade beyond its approximately 35 designated components, we discuss protein-protein interactions involving novel ligands and associations with signaling cascades and cellular networks that affect both inflammatory and non-inflammatory processes. This integrated consideration of complement within a unified 'systems biology' framework underscores the concept that innate immunity goes well beyond the protection

  6. Complement-mediated solubilization of immune complexes. Solubilization inhibition and complement factor levels in SLE patients

    DEFF Research Database (Denmark)

    Baatrup, Gunnar; Petersen, Ivan; Kappelgaard, E

    1984-01-01

    Thirty-two of 36 serum samples from 19 SLE patients showed reduced capacity to mediate complement-dependent solubilization of immune complexes (IC). SLE patients with nephritis exerted the lowest complement-mediated solubilization capacity (CMSC) whereas sera from patients with inactive disease...

  7. Complement propriety and conspiracy in nanomedicine

    DEFF Research Database (Denmark)

    Moghimi, Seyed Moein

    2016-01-01

    The complement system is the first line of body's defense against intruders and it acts as a functional bridge between innate and adaptive arms of the immune system. This commentary examines the key roles of complement activation in response to nanomedicine administration, including nucleic acid...... complexes. These comprise beneficial (eg, adjuvanticity) as well as adverse effects (eg, infusion-related reactions). Pigs (and sheep) are often used as predictive models of nanomedicine-mediated infusion-related reactions in humans. The validity of these models in relation to human responses is questioned...

  8. 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...... components in keratinocytes and epidermis following stimulation with proinflammatory cytokines. Importantly, EGFR inhibition of cultured keratinocytes either alone or in combination with proinflammatory stimulus promoted activation of the complement system after incubation with serum. In keratinocytes...... 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...

  9. Graphs whose complement and square are isomorphic

    DEFF Research Database (Denmark)

    Milanic, M.; Pedersen, Anders Sune; Pellicer, D.

    2014-01-01

    We study square-complementary graphs, that is, graphs whose complement and square are isomorphic. We prove several necessary conditions for a graph to be square-complementary, describe ways of building new square-complementary graphs from existing ones, construct infinite families of square-compl...

  10. Synapse remodeling, compliments of the complement system.

    Science.gov (United States)

    Fourgeaud, Lawrence; Boulanger, Lisa M

    2007-12-14

    A growing body of evidence indicates that some proteins known for their immune functions also have distinct nonimmune functions in the normal uninjured central nervous system. In this issue, Stevens et al. (2007) demonstrate an unexpected requirement for molecules of the complement cascade in the remodeling of synaptic connections in the developing visual system.

  11. 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.

  12. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. 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

    We present a new functional assay for the first complement component (C1) in plasma, based on its activation by inhibition of the C1-esterase inhibitor (C1-inh) when monospecific antiserum to C1-inh is added to the plasma. After maximal activation, we can determine the concentration of activated ...

  14. A scabies mite serpin interferes with complement-mediated neutrophil functions and promotes staphylococcal growth.

    Directory of Open Access Journals (Sweden)

    Pearl M Swe

    2014-06-01

    Full Text Available BACKGROUND: Scabies is a contagious skin disease caused by the parasitic mite Sarcoptes scabiei. The disease is highly prevalent worldwide and known to predispose to secondary bacterial infections, in particular by Streptococcus pyogenes and Staphylococcus aureus. Reports of scabies patients co-infected with methicillin resistant S. aureus (MRSA pose a major concern for serious down-stream complications. We previously reported that a range of complement inhibitors secreted by the mites promoted the growth of S. pyogenes. Here, we show that a recently characterized mite serine protease inhibitor (SMSB4 inhibits the complement-mediated blood killing of S. aureus. METHODOLOGY/PRINCIPAL FINDINGS: Blood killing of S. aureus was measured in whole blood bactericidal assays, counting viable bacteria recovered after treatment in fresh blood containing active complement and phagocytes, treated with recombinant SMSB4. SMSB4 inhibited the blood killing of various strains of S. aureus including methicillin-resistant and methicillin-sensitive isolates. Staphylococcal growth was promoted in a dose-dependent manner. We investigated the effect of SMSB4 on the complement-mediated neutrophil functions, namely phagocytosis, opsonization and anaphylatoxin release, by flow cytometry and in enzyme linked immuno sorbent assays (ELISA. SMSB4 reduced phagocytosis of S. aureus by neutrophils. It inhibited the deposition of C3b, C4b and properdin on the bacteria surface, but did not affect the depositions of C1q and MBL. SMSB4 also inhibited C5 cleavage as indicated by a reduced C5b-9 deposition. CONCLUSIONS/SIGNIFICANCE: We postulate that SMSB4 interferes with the activation of all three complement pathways by reducing the amount of C3 convertase formed. We conclude that SMSB4 interferes with the complement-dependent killing function of neutrophils, thereby reducing opsonization, phagocytosis and further recruitment of neutrophils to the site of infection. As a

  15. [ALK inhibitor].

    Science.gov (United States)

    Mano, Hiroyuki

    2011-01-01

    While lung cancer is the leading cause of cancer deaths worldwide, the molecular mechanism underlying its carcinogenesis is mainly unknown. We have discovered a small, fusion-type tyrosine kinase EML4-ALK that is generated through a tiny inversion within the short arm of human chromosome 2. Transgenic mice expressing EML4-ALK in lung developed hundreds of lung cancer nodules soon after birth, but such nodules were readily eradicated upon treatment with an ALK inhibitor. Clinical trials for EML4-ALK-positive lung cancer with an ALK inhibitor is ongoing, with its interim results being highly promising.

  16. 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

  17. Tanker avionics and aircrew complement evaluation.

    Science.gov (United States)

    Moss, R W; Barbato, G J

    1982-11-01

    This paper describes an effort to determine control and display criteria for operating SAC's KC-135 tanker with a reduced crew complement. The Tanker Avionics and Aircrew Complement Evaluation (TAACE) Program was a four-phase effort addressing the control and display design issues associated with operating the tanker without the navigator position. Discussed are: the mission analysis phase, during which the tanker's operational responsibilities were defined and documented; the design phase, during which alternative crew station design concepts were developed; the mockup evaluation phase, which accomplished initial SAC crew member assessment of cockpit designs; and the simulation phase, which validated the useability of the crew system redesign. The paper also describes a recommended crew station configuration and discusses some of the philosophy underlying the selection of cockpit hardware and systems.

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

    Directory of Open Access Journals (Sweden)

    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.

  19. Complement and Immunoregulation in Tissue Injury

    Science.gov (United States)

    2014-10-01

    components of the immune response. To date there is no specific therapy that has yet gained widespread clinical use for the prevention and treatment of...lymphocyte depletion and inhibition of complement activation. Despite significant advances in this field, no agent or 9 therapy has yet gained widespread...relative to ß actin expression. 11 Figure 3: Proposed schema illustrates the protective role of R-spondin3 in endothelial cells under hypoxic stress

  20. Angiogenesis Inhibitors

    Science.gov (United States)

    ... blood vessels “feed” growing tumors with oxygen and nutrients , allowing the cancer cells to invade nearby tissue , to move throughout ... any angiogenesis inhibitors currently being used to treat cancer in humans? Yes. The U.S. Food and Drug Administration (FDA) has approved bevacizumab to ...

  1. A zebrafish model for uremic toxicity: role of the complement pathway.

    Science.gov (United States)

    Berman, Nathaniel; Lectura, Melisa; Thurman, Josh; Reinecke, James; Raff, Amanda C; Melamed, Michal L; Reinecke, James; Quan, Zhe; Evans, Todd; Meyer, Timothy W; Hostetter, Thomas H

    2013-01-01

    Many organic solutes accumulate in end-stage renal disease (ESRD) and some are poorly removed with urea-based prescriptions for hemodialysis. However, their toxicities have been difficult to assess. We have employed an animal model, the zebrafish embryo, to test the toxicity of uremic serum compared to control. Serum was obtained from stable ESRD patients predialysis or from normal subjects. Zebrafish embryos 24 h postfertilization were exposed to experimental media at a water:human serum ratio of 3:1. Those exposed to serum from uremic subjects had significantly reduced survival at 8 h (19 ± 18 vs. 94 ± 6%, p 50 kDa, respectively). Heating serum abrogated its toxicity. EDTA, a potent inhibitor of complement by virtue of calcium chelation, reduced the toxicity of uremic serum compared to untreated uremic serum (96 ± 5 vs. 28 ± 20% survival, p < 0.016, chelated vs. nonchelated serum, respectively). Anti-factor B, a specific inhibitor of the alternative complement pathway, reduced the toxicity of uremic serum, compared to untreated uremic serum (98 ± 6 vs. 3 ± 9% survival, p < 0.016, anti-factor B treated vs. nontreated, respectively). Uremic serum is thus more toxic to zebrafish embryos than normal serum. Furthermore, this toxicity is associated with a fraction of large size, is inactivated by heat, and is reduced by both specific and nonspecific inhibitors of complement activation. Together these data lend support to the hypothesis that at least some uremic toxicities may be mediated by complement. Copyright © 2013 S. Karger AG, Basel.

  2. Role of complement in graft rejection after organ transplantation

    NARCIS (Netherlands)

    Bos, Ineke G. A.; ten Berge, Ineke J. M.; Hack, C. Erik

    2002-01-01

    Activation of the complement system may significantly contribute to the inflammatory reaction after solid organ transplantation. In allotransplantation, the complement system may be activated by ischemia/reperfusion and, possibly, by antibodies directed against the graft. In xenotransplantation from

  3. On Wiener index of graph complements

    Directory of Open Access Journals (Sweden)

    Jaisankar Senbagamalar

    2014-06-01

    Full Text Available Let $G$ be an $(n,m$-graph. We say that $G$ has property $(ast$ if for every pair of its adjacent vertices $x$ and $y$, there exists a vertex $z$, such that $z$ is not adjacent to either $x$ or $y$. If the graph $G$ has property $(ast$, then its complement $overline G$ is connected, has diameter 2, and its Wiener index is equal to $binom{n}{2}+m$, i.e., the Wiener index is insensitive of any other structural details of the graph $G$. We characterize numerous classes of graphs possessing property $(ast$, among which are trees, regular, and unicyclic graphs.

  4. Begin and start: aspect and complement choice

    Directory of Open Access Journals (Sweden)

    Tünde Nagy

    2008-01-01

    Full Text Available The paper offers a semantic analysis of begin and start and their non-finite complementation: the to-infinitive and –ing constructions. The core idea of the paper is that the aspectual constructions ‘begin+ to infinitive’, ‘begin + ing’, ‘start+ to infinitive’, and ‘start+ ing’ have both a schematic and a prototypical meaning, and that the subtle differences between them are motivated by several factors, like viewing (perfectivity vs. imperfectivity, temporality (future orientation vs. ongoing reading dynamicity (graduality vs. abruptness, agentivity, etc.

  5. Complement factor C4 activation in patients with hereditary angioedema

    DEFF Research Database (Denmark)

    Åbom, Anne; Bygum, Anette; Koch, Claus

    2017-01-01

    Objectives: Low complement factor C4 is usually considered a valuable screening tool for patients with the potentially life-threatening hereditary angioedema with C1-inhibitor (C1-INH) deficiency (C1-INH-HAE). However, there are patients with C1-INH-HAE presenting with normal C4 levels. This means......, that C1-INH-HAE may potentially be overlooked, if screening is performed only by measurement of C4. It has been suggested that measurement of C4 activation products is better suited to avoid false negative results. Our aim was to investigate whether total antigenic C4 or non-functional C4c is a better...... measure of the increased C4 activation in C1-INH-HAE patients. Design and methods: Two different monoclonal antibodies (mAb) to human C4 were produced: one had specificity for the β-chain of C4 and would thus react with both functional and non-functional C4, and the other was developed against the factor...

  6. Complement inhibition in biomaterial- and biosurface-induced thromboinflammation.

    Science.gov (United States)

    Ekdahl, Kristina N; Huang, Shan; Nilsson, Bo; Teramura, Yuji

    2016-06-01

    Therapeutic medicine today includes a vast number of procedures involving the use of biomaterials, transplantation of therapeutic cells or cell clusters, as well as of solid organs. These treatment modalities are obviously of great benefit to the patient, but also present a great challenge to the innate immune system, since they involve direct exposure of non-biological materials, cells of non-hematological origin as well as endothelial cells, damaged by ischemia-perfusion in solid organs to proteins and cells in the blood. The result of such an exposure may be an inappropriate activation of the complement and contact/kallikrein systems, which produce mediators capable of triggering the platelets and PMNs and monocytes, which can ultimately result in thrombotic and inflammatory (i.e., a thrombo-inflammatory) response to the treatment modality. In this concept review, we give an overview of the mechanisms of recognition within the innate immunity system, with the aim to identify suitable points for intervention. Finally, we discuss emerging and promising techniques for surface modification of biomaterials and cells with specific inhibitors in order to diminish thromboinflammation and improve clinical outcome. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. The role of ficolins and MASPs in hereditary angioedema due to C1-inhibitor deficiency

    DEFF Research Database (Denmark)

    Csuka, Dorottya; Munthe-Fog, Lea; Skjoedt, Mikkel-Ole

    2013-01-01

    Hereditary angioedema due to C1-inhibitor deficiency (HAE-C1-INH) causes disturbances in the complement system. However, the influence of HAE-C1-INH on the lectin pathway of complement is unresolved. Thus, we studied the main initiator molecules, enzymes and regulators in the lectin pathway...... in patients with HAE-C1-INH....

  8. The Production of Complement Clauses in Children with Language Impairment

    Science.gov (United States)

    Steel, Gillian; Rose, Miranda; Eadie, Patricia

    2016-01-01

    Purpose: The purpose of this research was to provide a comprehensive description of complement-clause production in children with language impairment. Complement clauses were examined with respect to types of complement structure produced, verb use, and both semantic and syntactic accuracy. Method: A group of 17 children with language impairment…

  9. 21 CFR 866.5240 - Complement components immunological test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Complement components immunological test system... SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunological Test Systems § 866.5240 Complement components immunological test system. (a) Identification. A complement components...

  10. The Ancient Complement System: Role in Physiology and Defense

    NARCIS (Netherlands)

    Kuipers, Saskia

    2003-01-01

    The Ancient Complement System: Role in Microbial Clearance, Lipid Transport and Prevention of Autoimmunity This study concentrates on the complement system, which is part of the nonspecific or ‘innate’ immune system. The complement system may be considered a primordial enzyme system that was,

  11. Pathogenic role of complement in renal ischemia/reperfusion injury

    NARCIS (Netherlands)

    Pol, Pieter van der

    2013-01-01

    The aim of the research described in this thesis was to study the role of complement in renal ischemia/reperfusion injury (IRI) and to delineate the contribution of the different complement pathways involved. So far, in human renal IRI, the activation pathways of complement by ischemic proximal

  12. 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...

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

    Science.gov (United States)

    Wang, Guankui; Chen, Fangfang; Banda, Nirmal K; Holers, V Michael; Wu, LinPing; Moghimi, S Moein; Simberg, Dmitri

    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 activation via calcium-sensitive pathways, but the AP was responsible for the bulk of complement activation and amplification. Activation via the AP required properdin, the positive regulator of the alternative C3bBb convertase. Modification of sugar alcohols of dextran with alkylating, acylating, or crosslinking agents did not overcome complement activation and C3 opsonization. These data demonstrate that human complement activation is independent of dextran modification of SPIO and suggest a crucial role of the AP in immune recognition of nano-assemblies in human serum.

  14. Early Neoplastic Progression Is Complement Independent

    Directory of Open Access Journals (Sweden)

    Karin E. de Visser

    2004-11-01

    Full Text Available Infiltration of leukocytes into premalignant tissue is a common feature of many epithelial neoplasms and is thought to contribute to cancer development. However, the molecular and cellular regulatory mechanisms underlying activation of innate host responses to enhanced neoplastic cell proliferation are largely unknown. Considering the importance of the complement system in regulating inflammation during acute pathologic tissue remodeling, we examined the functional significance of complement component 3 (C3 as a regulator of inflammatory cell infiltration and activation during malignant progression by using a transgenic mouse model of multistage epithelial carcinogenesis, e.g., HPV16 mice. Whereas abundant deposition of C3 is a characteristic feature of premalignant hyperplasias and dysplasias coincident with leukocyte infiltration in neoplastic tissue, genetic elimination of C3 neither affects inflammatory cell recruitment toward neoplastic skin nor impacts responding pathways downstream of inflammatory cell activation, e.g., keratinocyte hyperproliferation or angiogenesis. Taken together, these data suggest that complementindependent pathways are critical for leukocyte recruitment into neoplastic tissue and leukocytemediated potentiation of tumorigenesis.

  15. Participial Perception Verb Complements in Old English

    Directory of Open Access Journals (Sweden)

    Lowrey Brian

    2014-12-01

    Full Text Available In this paper, I shall examine the complements of perception verbs in Old English involving a noun phrase and a present participle. What kind of perception is described by these structures? Do they evoke the perception of an event, or that of an entity? It will be shown here that there are good reasons to believe that an NP + present participle sequence could function as the equivalent of the traditional “AcI” construction when used with perception verbs. I shall also attempt to determine to what extent the syntax of this construction matches the semantics: is the internal argument of the perception verb the NP alone, or some kind of combination of the NP and the participle? This question is particularly interesting in the light of Declerck’s (1982 remarks on participle perception verb complements in modern English. Finally, I shall take a look at morphological parametres: sometimes the participle inflects to agree with the NP, whereas on other occasions it does not. What might the implications of this kind of variation be?

  16. Modulatory Role of Surface Coating of Superparamagnetic Iron Oxide Nanoworms in Complement Opsonization and Leukocyte Uptake

    DEFF Research Database (Denmark)

    Inturi, Swetha; Wang, Guankui; Chen, Fangfang

    2015-01-01

    Notwithstanding rapid advances of nanotechnology in diagnostic imaging and drug delivery, the engineered nanocarriers still exhibit substantial lack of hemocompatibility. Thus, when injected systemically, nanoparticles are avidly recognized by blood leukocytes and platelets, but the mechanisms of...... alternative pathway and by nanoparticle surface coating. These results provide important insights into the mechanisms of hemocompatibility of nanomedicines.......Notwithstanding rapid advances of nanotechnology in diagnostic imaging and drug delivery, the engineered nanocarriers still exhibit substantial lack of hemocompatibility. Thus, when injected systemically, nanoparticles are avidly recognized by blood leukocytes and platelets, but the mechanisms...... leukocytes. The residual uptake of cross-linked nanoparticles was completely blocked by EDTA. These findings demonstrate species differences in complement-mediated nanoparticle recognition and uptake by leukocytes, and further show that human hemocompatibility could be improved by inhibitors of complement...

  17. Cholesterol Crystals Activate the Lectin Complement Pathway via Ficolin-2 and Mannose-Binding Lectin

    DEFF Research Database (Denmark)

    Pilely, Katrine; Rosbjerg, Anne; Genster, Ninette

    2016-01-01

    Cholesterol crystals (CC) play an essential role in the formation of atherosclerotic plaques. CC activate the classical and the alternative complement pathways, but the role of the lectin pathway is unknown. We hypothesized that the pattern recognition molecules (PRMs) from the lectin pathway bind...... CC and function as an upstream innate inflammatory signal in the pathophysiology of atherosclerosis. We investigated the binding of the PRMs mannose-binding lectin (MBL), ficolin-1, ficolin-2, and ficolin-3, the associated serine proteases, and complement activation products to CC in vitro using...... recombinant proteins, specific inhibitors, as well as deficient and normal sera. Additionally, we examined the deposition of ficolin-2 and MBL in human carotid plaques by immunohistochemistry and fluorescence microscopy. The results showed that the lectin pathway was activated on CC by binding of ficolin-2...

  18. C1 esterase inhibitor

    Science.gov (United States)

    ... protein called C1, which is part of the complement system. This system is a group of proteins that ... 2013:chap 20. Sullivan KE, Grumach AS. The complement system. In: Adkinson NF, Bochner BS, Burks AW, et ...

  19. Theoretical implications of complement structure acquisition in Korean.

    Science.gov (United States)

    Kim, Y J

    1989-10-01

    The acquisition of complement phrasal constructions in Korean is examined in spontaneous speech data from two children, who were observed from one and a half to three years of age. In spite of typological differences between English and Korean, both syntactic and semantic characteristics are found to be shared by children acquiring complement constructions in the two languages. However, certain language-specific features of Korean complement structures make it possible to address theoretical points concerning the structure of infinitival complements which cannot be resolved with the acquisition data on English. The error pattern in the acquisition of certain 'subject-equi' verbs in Korean poses problems both for LFG and GB accounts of the constituent structure of infinitival complements and the acquisition of those constructions. On the basis of the Korean data, I propose that base-generated VP complements are acquired first, with semantically motivated reanalysis of previously acquired infinitival complement structures occurring at a later stage.

  20. Masturbation and Partnered Sex: Substitutes or Complements?

    Science.gov (United States)

    Regnerus, Mark; Price, Joseph; Gordon, David

    2017-10-01

    Drawing upon a large, recent probability sample of American adults ages 18-60 (7648 men and 8090 women), we explored the association between sexual frequency and masturbation, evaluating the evidence for whether masturbation compensates for unavailable sex, complements (or augments) existing paired sexual activity, or bears little association with it. We found evidence supporting a compensatory relationship between masturbation and sexual frequency for men, and a complementary one among women, but each association was both modest and contingent on how content participants were with their self-reported frequency of sex. Among men and women, both partnered status and their sexual contentment were more obvious predictors of masturbation than was recent frequency of sex. We conclude that both hypotheses as commonly evaluated suffer from failing to account for the pivotal role of subjective sexual contentment in predicting masturbation.

  1. Genetic complementation groups in cockayne syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, K.; Kawai, K.; Kumahara, Y.; Ikenaga, M.; Okada, Y.

    1981-07-01

    Skin fibroblasts from patients with cockayne syndrome (CS cell) exhibited marked ultraviolet (UV) sensitivity as measured by colony-forming ability. Further, recovery of semiconservative DNA synthesis following UV irradiation was absent in CS cells, as it is in xeroderma pigmentosum cells. We found that the rate of semiconservative DNA synthesis measured at 12 h after 12 J/m2 of UV irradiation had recovered to nearly normal levels in binuclear cells obtained by the fusion of CS strains CS3BE (GM 1856) and CS7SE (GM1428) and of CS3BE (GM1856) and CS1BE (GM1629), but not of C57SE (GM1428) and CS1BE (GM1629). These results indicate that there are at least two genetic complementation groups in CS.

  2. Lectin Complement Pathway Proteins in Healthy Individuals

    DEFF Research Database (Denmark)

    Troldborg, Anne; Hansen, Annette Gudmann; Hansen, Søren W K

    2017-01-01

    Since the discovery of the lectin pathway of complement activation, numerous clinical cohorts have been examined for one or more of the proteins, with the intention of uncovering the functions of the proteins or with the aim of discovering new biomarkers or diagnostic tools. To unveil the abnormal......, it is pivotal to know the normal. Our aim was to describe the concentrations of the eleven known proteins of the lectin pathway in serum and plasma and to uncover possible gender differences, age and diurnal variations, which must be taken into account for investigations in different cohorts. We examined...... the concentrations of all lectin pathway proteins (mannan-binding lectin (MBL), H-ficolin, L-ficolin, M-ficolin, collectin-K1, collectin-L1, MBL-associated serine protease 2 (MASP-2), MASP-3, MBL associated protein of 44 kDa (MAp44) and MAp19 in 300 Danish blood donors in serum and EDTA plasma in established assays...

  3. 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.

  4. Complementing theoretical biochemistry with the uso of computer aids (Symposium

    Directory of Open Access Journals (Sweden)

    R Herrera

    2012-05-01

    Full Text Available Teaching  biochemistry  in  the  current  state  of  science  and  society  requires  a  special motivation for learning, especially for students where Biochemistry is one of the courses on  their  careers.  The  traditional  way  of  teaching,  based  on  the  teacher-student relationship,  mostly  unidirectional,  does  not  fulfil  the  needs  imposed  in  this  era. Considering  the  current  situation,  University  students  require  new  abilities  in  their training  and  the  use  of  computers  can  be  a  facility  for  discovering  and  research, enabling the experience of new and  diverse situations. The design of teaching material for undergraduate students who take biochemistry as complementary course should be seen  as  an  opportunity  to  complement  theoretical  aspect  on  the  current  courses.  We have used three different approaches: (I Modelling proteins indicating key motifs at the three-dimensional structure and residues where inhibitors can be attach. (II Generation of  activities  by  the  use  of  sensors.  And  (III  elaborating  active  quizzes  where  students can  be  drive  on  their  learning.  Building  knowledge  based  on  practical  experience  can improve  student’s  competence  on  basic  science  and  the  learning  process  can  be complemented in the use of dynamics models.

  5. Complement regulation and kidney diseases: recent knowledge of the double-edged roles of complement activation in nephrology.

    Science.gov (United States)

    Mizuno, Masashi; Suzuki, Yasuhiro; Ito, Yasuhiko

    2017-03-24

    The complement activation system plays important roles to maintain homeostasis in the host and to fight foreign invaders to protect the host. Therefore, the complement system is considered a core part of innate immunity which also cross-talks to acquired immunity. In the history of nephrology, the complement system is familiar to us, because complement protein or fragment deposition, including C3, C4, C1q, and/or C4d, is routinely estimated by immunohistochemistry to diagnose renal pathologies. The relationships between pathological mechanisms and complement activation have been investigated for renal diseases such as post-infectious glomerulonephritis, lupus nephritis, and primary membranoproliferative glomerulonephritis, which are usually accompanied by hypocomplementemia. However, unregulated complement activation in local areas might be associated with progression of various renal injuries even in the normocomplementemic patient. Recently, attention has focused on dysfunction of complement regulation in various diseases including renal diseases such as atypical hemolytic uremic syndrome and C3 glomerulopathy. Some mechanisms associated with complement activation in these diseases were clarified. In addition, lots of anti-complement agents were developed and some of the agents have become clinically available. Now, anti-complement therapies represent a realistic choice of therapeutic approaches for complement-related diseases. Research on roles of complement activation is proceeding into new stages in the field of nephrology and in other fields involving both basic and clinical research. We herein summarize relationships between the complement activation and regulation systems, their physiological effects and roles in maintenance of homeostasis in the host, and how dysregulation of the complement system triggers disease, especially renal disease.

  6. Early complement activation follows eversion carotid endarterectomy and correlates with the time of clamping of the carotid artery

    DEFF Research Database (Denmark)

    Széplaki, Gábor; Hirschberg, Kristóf; Gombos, Tímea

    2008-01-01

    BACKGROUND: Complement activation plays an important role in ischemia/reperfusion (I/R) injury. The objective of the present study was to detect the presence and mechanism of complement activation in patients who underwent carotid endarterectomy (CEA). METHODS: Complement activation products C1rsC1......-inhibitor, C4d, C3a and SC5b-9 and concentrations of C-reactive protein (CRP) were measured in samples serially taken from 16 patients with eversion CEA and 10 with carotid artery stenting (CAS) in the first 24h post-surgery/intervention. MBL2 genotypes were also determined. RESULTS: In patients with CEA...... an intense increase in C3a levels were observed immediately after surgery (pcarotid...

  7. Expression, purification, cocrystallization and preliminary crystallographic analysis of sucrose octasulfate/human complement regulator factor H SCRs 6–8

    Energy Technology Data Exchange (ETDEWEB)

    Prosser, Beverly E.; Johnson, Steven; Roversi, Pietro [The Sir William Dunn School of Pathology, The University of Oxford, South Parks Road, Oxford OX1 3RE (United Kingdom); Clark, Simon J. [Faculty of Life Sciences, Manchester University, Michael Smith Building, Oxford Road, Manchester M13 9PT (United Kingdom); Tarelli, Edward [Medical Biomics Centre, St George’s, University of London, Cranmer Terrace, London SW17 0RE (United Kingdom); Sim, Robert B. [The MRC Immunochemistry Unit, The University of Oxford, South Parks Road, Oxford OX1 3RE (United Kingdom); Day, Antony J. [Faculty of Life Sciences, Manchester University, Michael Smith Building, Oxford Road, Manchester M13 9PT (United Kingdom); Lea, Susan M., E-mail: susan.lea@bnc.ox.ac.uk [The Sir William Dunn School of Pathology, The University of Oxford, South Parks Road, Oxford OX1 3RE (United Kingdom)

    2007-06-01

    The crystallization of human complement regulator FH-678{sub 402H} with a glycosaminoglycan analogue is described. Human plasma protein complement factor H (FH) is an inhibitor of the spontaneously activated alternative complement pathway. An allotypic variant of FH, 402His, has been associated with age-related macular degeneration, the leading cause of blindness in the elderly. Crystals of FH domains 6–8 (FH678) containing 402His have been grown in the presence of a polyanionic sucrose octasulfate ligand (an analogue of the natural glycosaminoglycan ligands of FH) using both native and selenomethionine-derivatized protein. Native data sets diffracting to 2.3 Å and SeMet data sets of up to 2.8 Å resolution have been collected. An anomalous difference Patterson map reveals self- and cross-peaks from two incorporated Se atoms. The corresponding selenium substructure has been solved.

  8. Limited proteolysis of beta 2-microglobulin at Lys-58 by complement component C1s

    DEFF Research Database (Denmark)

    Nissen, Mogens Holst; Roepstorff, P; Thim, L

    1990-01-01

    a modified form of beta 2-microglobulin with a two-chain structure. The C-terminal Lys-58 in the A chain is highly susceptible to removal by a carboxypeptidase-B-like activity causing the formation of des-Lys58-beta 2-microglobulin. This is the first demonstration of a noncomplement protein substrate......We have now demonstrated that activated complement component C1s cleaves beta 2-microglobulin at the position identical to that at which beta 2-microglobulin is cleaved in serum of patients suffering from lung cancer. The main cleavage is in the disulphide loop C-terminal to Lys-58, generating...... for the proteolytic activity of C1s. The C1s-induced cleavage of beta 2-microglobulin can be inhibited in the presence of C1 esterase inhibitor, demonstrating a regulatory function of C1 esterase inhibitor in the C1s-induced cleavage of beta 2-microglobulin....

  9. Endogenous C1-inhibitor production and expression in the heart after acute myocardial infarction.

    Science.gov (United States)

    Emmens, Reindert W; Baylan, Umit; Juffermans, Lynda J M; Karia, Rashmi V; Ylstra, Bauke; Wouters, Diana; Zeerleder, Sacha; Simsek, Suat; van Ham, Marieke; Niessen, Hans W M; Krijnen, Paul A J

    2016-01-01

    Complement activation contributes significantly to inflammation-related damage in the heart after acute myocardial infarction. Knowledge on factors that regulate postinfraction complement activation is incomplete however. In this study, we investigated whether endogenous C1-inhibitor, a well-known inhibitor of complement activation, is expressed in the heart after acute myocardial infarction. C1-inhibitor and complement activation products C3d and C4d were analyzed immunohistochemically in the hearts of patients who died at different time intervals after acute myocardial infarction (n=28) and of control patients (n=8). To determine putative local C1-inhibitor production, cardiac transcript levels of the C1-inhibitor-encoding gene serping1 were determined in rats after induction of acute myocardial infarction (microarray). Additionally, C1-inhibitor expression was analyzed (fluorescence microscopy) in human endothelial cells and rat cardiomyoblasts in vitro. C1-inhibitor was found predominantly in and on jeopardized cardiomyocytes in necrotic infarct cores between 12h and 5days old. C1-inhibitor protein expression coincided in time and colocalized with C3d and C4d. In the rat heart, serping1 transcript levels were increased from 2h up until 7days after acute myocardial infarction. Both endothelial cells and cardiomyoblasts showed increased intracellular expression of C1-inhibitor in response to ischemia in vitro (n=4). These observations suggest that endogenous C1-inhibitor is likely involved in the regulation of complement activity in the myocardium following acute myocardial infarction. Observations in rat and in vitro suggest that C1-inhibitor is produced locally in the heart after acute myocardial infarction. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Isolated oedema of the uvula induced by intense snoring and ACE inhibitor

    DEFF Research Database (Denmark)

    Rasmussen, Eva Rye; Mey, Kristianna; Bygum, Anette

    2014-01-01

    A case of snoring-induced angioedema of uvula is described in a patient who was treated with ACE inhibitor. The patient partially responded to complement C1-inhibitor concentrate and did not suffer any recurrences after the medication was withdrawn. When encountering a patient suffering from...

  11. The role of the complement system in cancer.

    Science.gov (United States)

    Afshar-Kharghan, Vahid

    2017-03-01

    In addition to being a component of innate immunity and an ancient defense mechanism against invading pathogens, complement activation also participates in the adaptive immune response, inflammation, hemostasis, embryogenesis, and organ repair and development. Activation of the complement system via classical, lectin, or alternative pathways generates anaphylatoxins (C3a and C5a) and membrane attack complex (C5b-9) and opsonizes targeted cells. Complement activation end products and their receptors mediate cell-cell interactions that regulate several biological functions in the extravascular tissue. Signaling of anaphylatoxin receptors or assembly of membrane attack complex promotes cell dedifferentiation, proliferation, and migration in addition to reducing apoptosis. As a result, complement activation in the tumor microenvironment enhances tumor growth and increases metastasis. In this Review, I discuss immune and nonimmune functions of complement proteins and the tumor-promoting effect of complement activation.

  12. Genetic complementation studies of multiple sulfatase deficiency.

    Science.gov (United States)

    Horwitz, A L

    1979-12-01

    Cultured fibroblasts from two individuals with multiple sulfatase deficiency (MSD) were found to have decreased activities of arylsulfatases (aryl-sulfate sulfohydrolase, EC 3.1.6.1) A, B, and C as well as iduronate-sulfate sulfatase, sulfamidase, and N-acetylglucosamine-6-sulfate sulfatase. The activity of N-acetylgalactosamine-6-sulfate sulfatase was decreased in one line but not in the other. Mixtures of MSD cell extracts with extracts from normal cells did not result in inhibition of normal sulfatase activities. Mixtures of MSD cell extracts with extracts of fibroblasts from patients with Hunter or Sanfilippo A syndrome did not activate iduronate-sulfate sulfatase or sulfamidase activity. Heterokaryons formed by fusion of MSD cells with Sanfilippo A fibroblasts demonstrated a partial correction of the enzyme deficiency. In similar manner, MSD-Hunter heterokaryons showed a significant increase in iduronate-sulfate-sulfatase activity. Genetic complementation in heterokaryons of MSD fibroblasts and cells of either Sanfilippo A or Hunter syndrome implies a genetic defect in MSD different from that causing specific sulfatase deficiencies.

  13. A targeted complement-dependent strategy to improve the outcome of mAb therapy, and characterization in a murine model of metastatic cancer

    Science.gov (United States)

    Elvington, Michelle; Huang, Yuxiang; Morgan, B. Paul; Qiao, Fei; van Rooijen, Nico; Atkinson, Carl

    2012-01-01

    Complement inhibitors expressed on tumor cells provide an evasion mechanism against mAb therapy and may modulate the development of an acquired antitumor immune response. Here we investigate a strategy to amplify mAb-targeted complement activation on a tumor cell, independent of a requirement to target and block complement inhibitor expression or function, which is difficult to achieve in vivo. We constructed a murine fusion protein, CR2Fc, and demonstrated that the protein targets to C3 activation products deposited on a tumor cell by a specific mAb, and amplifies mAb-dependent complement activation and tumor cell lysis in vitro. In syngeneic models of metastatic lymphoma (EL4) and melanoma (B16), CR2Fc significantly enhanced the outcome of mAb therapy. Subsequent studies using the EL4 model with various genetically modified mice and macrophage-depleted mice revealed that CR2Fc enhanced the therapeutic effect of mAb therapy via both macrophage-dependent FcγR-mediated antibody-dependent cellular cytotoxicity, and by direct complement-mediated lysis. Complement activation products can also modulate adaptive immunity, but we found no evidence that either mAb or CR2Fc treatment had any effect on an antitumor humoral or cellular immune response. CR2Fc represents a potential adjuvant treatment to increase the effectiveness of mAb therapy of cancer. PMID:22442351

  14. C-reactive protein and natural IgM antibodies are activators of complement in a rat model of intestinal ischemia and reperfusion

    NARCIS (Netherlands)

    Padilla, Niubel Diaz; van Vliet, Arlene K.; Schoots, Ivo G.; Seron, Mercedes Valls; Maas, M. Adrie; Peltenburg, Esther E. Posno; de Vries, Annebeth; Niessen, Hans W. M.; Hack, C. Erik; van Gulik, Thomas M.

    2007-01-01

    Background. The role of C-reactive protein (CRP), natural immunoglobulin M (IgM), and natural IgM against phosphorylcholine (anti-Pc IgM) was investigated in relation with complement activation in a rat model of intestinal ischemia and reperfusion (II/R). The effect of Cl-esterase inhibitor (C1-Inh)

  15. Complement Receptor Type 1 Suppresses Human B Cell Functions in SLE Patients

    Directory of Open Access Journals (Sweden)

    Mariann Kremlitzka

    2016-01-01

    Full Text Available Complement receptors (CRs play an integral role in innate immunity and also function to initiate and shape the adaptive immune response. Our earlier results showed that complement receptor type 1 (CR1, CD35 is a potent inhibitor of the B cell receptor- (BCR- induced functions of human B lymphocytes. Here we show that this inhibition occurs already at the initial steps of B cell activation since ligation of CR1 reduces the BCR-induced phosphorylation of key signaling molecules such as Syk and mitogen activated protein kinases (MAPKs. Furthermore, our data give evidence that although B lymphocytes of active systemic lupus erythematosus (SLE patients express lower level of CR1, the inhibitory capacity of this complement receptor is still maintained and its ligand-induced clustering results in significant inhibition of the main B cell functions, similar to that found in the case of healthy individuals. Since we have found that reduced CR1 expression of SLE patients does not affect the inhibitory capacity of the receptor, our results further support the therapeutical potential of CD35 targeting the decrease of B cell activation and autoantibody production in autoimmune patients.

  16. Complement Receptor Type 1 Suppresses Human B Cell Functions in SLE Patients.

    Science.gov (United States)

    Kremlitzka, Mariann; Mácsik-Valent, Bernadett; Polgár, Anna; Kiss, Emese; Poór, Gyula; Erdei, Anna

    2016-01-01

    Complement receptors (CRs) play an integral role in innate immunity and also function to initiate and shape the adaptive immune response. Our earlier results showed that complement receptor type 1 (CR1, CD35) is a potent inhibitor of the B cell receptor- (BCR-) induced functions of human B lymphocytes. Here we show that this inhibition occurs already at the initial steps of B cell activation since ligation of CR1 reduces the BCR-induced phosphorylation of key signaling molecules such as Syk and mitogen activated protein kinases (MAPKs). Furthermore, our data give evidence that although B lymphocytes of active systemic lupus erythematosus (SLE) patients express lower level of CR1, the inhibitory capacity of this complement receptor is still maintained and its ligand-induced clustering results in significant inhibition of the main B cell functions, similar to that found in the case of healthy individuals. Since we have found that reduced CR1 expression of SLE patients does not affect the inhibitory capacity of the receptor, our results further support the therapeutical potential of CD35 targeting the decrease of B cell activation and autoantibody production in autoimmune patients.

  17. The profile of adsorbed plasma and serum proteins on methacrylic acid copolymer beads: Effect on complement activation.

    Science.gov (United States)

    Wells, Laura A; Guo, Hongbo; Emili, Andrew; Sefton, Michael V

    2017-02-01

    Polymer beads made of 45% methacrylic acid co methyl methacrylate (MAA beads) promote vascular regenerative responses in contrast to control materials without methacrylic acid (here polymethyl methacrylate beads, PMMA). In vitro and in vivo studies suggest that MAA copolymers induce differences in macrophage phenotype and polarization and inflammatory responses, presumably due to protein adsorption differences between the beads. To explore differences in protein adsorption in an unbiased manner, we used high resolution shotgun mass spectrometry to identify and compare proteins that adsorb from human plasma or serum onto MAA and PMMA beads. From plasma, MAA beads adsorbed many complement proteins, such as C1q, C4-related proteins and the complement inhibitor factor H, while PMMA adsorbed proteins, such as albumin, C3 and apolipoproteins. Because of the differences in complement protein adsorption, follow-up studies focused on using ELISA to assess complement activation. When incubated in serum, MAA beads generated significantly lower levels of soluble C5b9 and C3a/C3adesarg in comparison to PMMA beads, indicating a decrease in complement activation with MAA beads. The differences in adsorbed protein on the two materials likely alter subsequent cell-material interactions that ultimately result in different host responses and local vascularization. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Sodium polyanethole sulfonate as an inhibitor of activation of complement function in blood culture systems

    DEFF Research Database (Denmark)

    Palarasah, Yaseelan; Skjoedt, Mikkel-Ole; Vitved, Lars

    2010-01-01

    Sodium polyanethole sulfonate (SPS; trade name, Liquoid) is a constituent in culture media used to grow bacteria from blood samples from patients suspected of bacteremia. SPS prevents the killing of bacteria by innate cellular and humoral factors. We analyzed the effect of SPS on the three...

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

    Czech Academy of Sciences Publication Activity Database

    Ferreira, V.P.; Vale, V.F.; Pangburn, M.K.; Abdeladhim, M.; Mendes-Sousa, A.F.; Coutinho-Abreu, I.V.; Rasouli, M.; Brandt, E.A.; Meneses, C.; Lima, K.F.; Araújo, R.N.; Pereira, M.H.; Kotsyfakis, Michalis; Oliveira, F.; Kamhawi, S.; Ribeiro, J.M.C.; Gontijo, N.F.; Collin, N.; Valenzuela, J. G.

    2016-01-01

    Roč. 6, JAN 13 (2016), č. článku 19300. ISSN 2045-2322 R&D Projects: GA ČR GAP502/12/2409 Institutional support: RVO:60077344 Keywords : leishmania * immunity * glands Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.259, year: 2016

  20. CD38 expression and complement inhibitors affect response and resistance to daratumumab therapy in myeloma

    NARCIS (Netherlands)

    Nijhof, Inger S; Casneuf, Tineke; van Velzen, Jeroen|info:eu-repo/dai/nl/41399547X; van Kessel, Berris; Axel, Amy E; Syed, Khaja; Groen, Richard W J; van Duin, Mark; Sonneveld, Pieter; Minnema, Monique C|info:eu-repo/dai/nl/171618149; Zweegman, Sonja; Chiu, Christopher; Bloem, Andries C|info:eu-repo/dai/nl/071168656; Mutis, Tuna; Lokhorst, Henk M; Sasser, A Kate; van de Donk, Niels W C J

    2016-01-01

    The anti-CD38 monoclonal antibody daratumumab is well tolerated and has high single agent activity in heavily pretreated relapsed and refractory multiple myeloma (MM). However, not all patients respond, and many patients eventually develop progressive disease to daratumumab monotherapy. We therefore

  1. Endogenous and natural complement inhibitor attenuates myocardial injury and arterial thrombogenesis

    DEFF Research Database (Denmark)

    Pavlov, Vasile I; Skjoedt, Mikkel-Ole; Siow Tan, Ying

    2012-01-01

    BACKGROUND: Coagulation disorders and reperfusion of ischemic myocardium are major causes of morbidity and mortality. Lectin pathway initiation complexes are composed of multimolecular carbohydrate recognition subcomponents and 3 lectin pathway-specific serine proteases. We have recently shown th...

  2. Development of Complement Inhibitors to Limit Tissue as Adjuvants to Resuscitation

    Science.gov (United States)

    2010-03-01

    which time the principle of vascular repair to restore arterial continuity was practiced rather than vessel ligation [2]. While this preserved limb...enterocolitis, repair of abdominal aortic aneurysms , and acute mesen- teric ischemia.ACKNOWLEDGMENTS The authors acknowledge support for this work by the... coronary artery occlusion. J Clin Invest 61: 541–551, 1978. 26. Manfredi AA, Rovere P, Heltai S, Galati G, Nebbia G, Tincani A, Balestrieri G, Sabbadini MG

  3. Complement factor 5 blockade reduces porcine myocardial infarction size and improves immediate cardiac function.

    Science.gov (United States)

    Pischke, Soeren E; Gustavsen, A; Orrem, H L; Egge, K H; Courivaud, F; Fontenelle, H; Despont, A; Bongoni, A K; Rieben, R; Tønnessen, T I; Nunn, M A; Scott, H; Skulstad, H; Barratt-Due, A; Mollnes, T E

    2017-05-01

    Inhibition of complement factor 5 (C5) reduced myocardial infarction in animal studies, while no benefit was found in clinical studies. Due to lack of cross-reactivity of clinically used C5 antibodies, different inhibitors were used in animal and clinical studies. Coversin (Ornithodoros moubata complement inhibitor, OmCI) blocks C5 cleavage and binds leukotriene B4 in humans and pigs. We hypothesized that inhibition of C5 before reperfusion will decrease infarct size and improve ventricular function in a porcine model of myocardial infarction. In pigs (Sus scrofa), the left anterior descending coronary artery was occluded (40 min) and reperfused (240 min). Coversin or placebo was infused 20 min after occlusion and throughout reperfusion in 16 blindly randomized pigs. Coversin significantly reduced myocardial infarction in the area at risk by 39% (p = 0.03, triphenyl tetrazolium chloride staining) and by 19% (p = 0.02) using magnetic resonance imaging. The methods correlated significantly (R = 0.92, p infarcted area at risk by coversin treatment. Coversin ablated plasma C5 activation throughout the reperfusion period and decreased myocardial C5b-9 deposition, while neither plasma nor myocardial LTB4 were significantly reduced. Coversin substantially reduced the size of infarction, improved ventricular function, and attenuated interleukin-1β and E-selectin in this porcine model by inhibiting C5. We conclude that inhibition of C5 in myocardial infarction should be reconsidered.

  4. Targeted Delivery of Neutralizing Anti-C5 Antibody to Renal Endothelium Prevents Complement-Dependent Tissue Damage

    Directory of Open Access Journals (Sweden)

    Paolo Durigutto

    2017-09-01

    Full Text Available Complement activation is largely implicated in the pathogenesis of several clinical conditions and its therapeutic neutralization has proven effective in preventing tissue and organ damage. A problem that still needs to be solved in the therapeutic control of complement-mediated diseases is how to avoid side effects associated with chronic neutralization of the complement system, in particular, the increased risk of infections. We addressed this issue developing a strategy based on the preferential delivery of a C5 complement inhibitor to the organ involved in the pathologic process. To this end, we generated Ergidina, a neutralizing recombinant anti-C5 human antibody coupled with a cyclic-RGD peptide, with a distinctive homing property for ischemic endothelial cells and effective in controlling tissue damage in a rat model of renal ischemia/reperfusion injury (IRI. As a result of its preferential localization on renal endothelium, the molecule induced complete inhibition of complement activation at tissue level, and local protection from complement-mediated tissue damage without affecting circulating C5. The ex vivo binding of Ergidina to surgically removed kidney exposed to cold ischemia supports its therapeutic use to prevent posttransplant IRI leading to delay of graft function. Moreover, the finding that the ex vivo binding of Ergidina was not restricted to the kidney, but was also seen on ischemic heart, suggests that this RGD-targeted anti-C5 antibody may represent a useful tool to treat organs prior to transplantation. Based on this evidence, we propose preliminary data showing that Ergidina is a novel targeted drug to prevent complement activation on the endothelium of ischemic kidney.

  5. Lectin complement pathway proteins in healthy individuals.

    Science.gov (United States)

    Troldborg, A; Hansen, A; Hansen, S W K; Jensenius, J C; Stengaard-Pedersen, K; Thiel, S

    2017-04-01

    Since the discovery of the lectin pathway of complement activation, numerous clinical cohorts have been examined for one or more proteins, with the intention of uncovering the functions of the proteins or with the aim of discovering new biomarkers or diagnostic tools. To unveil the abnormal, it is pivotal to know the normal. Our aim was to describe the concentrations of the 11 known proteins of the lectin pathway in serum and plasma and to uncover possible gender differences, age and diurnal variations, which must be taken into account for investigation in different cohorts. We examined the concentrations of all lectin pathway proteins mannan-binding lectin (MBL), H-ficolin, L-ficolin, M-ficolin, collectin-K1, collectin-L1, MBL-associated serine protease 2 (MASP-2), MASP-3, MBL-associated protein of 44 kDa (MAp44) and MAp19 in 300 Danish blood donors in serum and ethylenediamine tetraacetic acid (EDTA) plasma in established assays, and we further developed a new assay to measure MASP-1 in the same samples. We found significant differences in concentrations between serum and plasma for all proteins except for MBL and MASP-3. H-ficolin, M-ficolin and MAp19 displayed convincing diurnal variation. H-ficolin, in particular, halved from morning to the middle of the night. There were gender differences for most proteins, whereas age did not seem to influence concentration. The present study underlines the necessity of considering which material to use, correct matching and a trial design that takes the nature of the protein into account in order for the outcome of cohort studies to have significant relevance. © 2016 British Society for Immunology.

  6. Complement susceptibility in glutamine deprived breast cancer cells

    Directory of Open Access Journals (Sweden)

    Boackle Robert J

    2007-07-01

    Full Text Available Abstract Background Membrane complement regulatory proteins (mCRPs inhibit complement-mediated killing of human cells by human complement, a property that confers protection from complement to malignant breast cancer cells and that thwarts some immunotherapies. Metabolic mechanisms may come into play in protecting cancer cells from the complement system subsequent to relatively low levels of complement deposition. Results In differentiating these mechanisms, two types of human breast cancer cell lines, MCF7 (adenocarcinoma and Bcap37 (medullary carcinoma were cell-cycle synchronized using glutamine-deprivation followed by restoration. These cells were examined for the expression of two mCRPs (CD59 and CD55, and for subsequent susceptibility to antibody-mediated complement-induced membrane damage. After glutamine restoration, MCF7 and Bcap37 cells were synchronized into the G2/M phase and an average increased expression of CD59 and CD55 occurred with a corresponding resistance to complement-mediated damage. Blocking CD59 inhibitory function with monoclonal antibody revealed that CD59 played a key role in protecting unsynchronized Bcap37 and MCF7 cancer cells from the complement membrane attack complex. Interestingly, glutamine-deprivation did not significantly affect the expression of proteins e.g., the surface level of CD59 or CD55, but did increase the susceptibility to complement-mediated killing. One possible explanation is that glutamine-deprivation may have slowed the turnover rate of mCRPs, preventing the cells from replacing pre-existing mCRPs, as they became neutralized by covalent C4b and C3b depositions. Conclusion Taken together the findings are consistent with the conclusion that future immunotherapies should aim to achieve a highly specific and profound activation and deposition of complement as well as to disrupt the synthesis and expression of CD59 and CD55 by the cancer cells.

  7. 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.

  8. 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.

  9. Demand Heterogeneity and the Adoption of Platform Complements

    NARCIS (Netherlands)

    G.J. Rietveld (Joost); J.P. Eggers

    2016-01-01

    textabstractThis paper offers a demand-based theory of how platform maturity affects the adoption of platform complements. We argue that differences between early and late adopters of the platform include willingness to pay for the platform-and-complement bundle, risk preferences, preference for

  10. 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. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. The role of complement activation in thrombosis and hemolytic anemias.

    Science.gov (United States)

    Chapin, John; Terry, Hunter S; Kleinert, Dorothy; Laurence, Jeffrey

    2016-04-01

    The objective of this study was to describe complement activation in hemostatic and pathologic states of coagulation and in the acquired and congenital hemolytic anemias. We review published and emerging data on the involvement of the classic, alternative and lectin-based complement pathways in coagulation and the hemolytic anemias. The alternative pathway in particular is always "on," at low levels, and is particularly sensitive to hyper-activation in a variety of physiologic and pathologic states including infection, autoimmune disorders, thrombosis and pregnancy, requiring tight control predicated on a variety of soluble and membrane bound regulatory proteins. In acquired hemolytic anemias such as paroxysmal nocturnal hemoglobinuria (PNH) and cold agglutinin disease (CAD), the complement system directly induces red blood cell injury, resulting in intravascular and extravascular hemolysis. In congenital hemolytic anemias such as sickle cell disease and β-thalassemia, the complement system may also contribute to thrombosis and vascular disease. Complement activation may also lead to a storage lesion in red blood cells prior to transfusion. Complement pathways are activated in hemolytic anemias and are closely linked with thrombosis. In acquired disorders such as PNH and possibly CAD, inhibition of the alternative complement pathway improves clinical outcomes and reduces thrombosis risk. Whether complement inhibition has a similar role in congenital hemolytic anemias apart from the atypical hemolytic-uremic (aHUS)-type thrombotic microangiopathies remains to be determined. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Complement Attack against Aspergillus and Corresponding Evasion Mechanisms

    Directory of Open Access Journals (Sweden)

    Cornelia Speth

    2012-01-01

    Full Text Available Invasive aspergillosis shows a high mortality rate particularly in immunocompromised patients. Perpetually increasing numbers of affected patients highlight the importance of a clearer understanding of interactions between innate immunity and fungi. Innate immunity is considered to be the most significant host defence against invasive fungal infections. Complement represents a crucial part of this first line defence and comprises direct effects against invading pathogens as well as bridging functions to other parts of the immune network. However, despite the potency of complement to attack foreign pathogens, the prevalence of invasive fungal infections is increasing. Two possible reasons may explain that phenomenon: First, complement activation might be insufficient for an effective antifungal defence in risk patients (due to, e.g., low complement levels, poor recognition of fungal surface, or missing interplay with other immune elements in immunocompromised patients. On the other hand, fungi may have developed evasion strategies to avoid recognition and/or eradication by complement. In this review, we summarize the most important interactions between Aspergillus and the complement system. We describe the various ways of complement activation by Aspergillus and the antifungal effects of the system, and also show proven and probable mechanisms of Aspergillus for complement evasion.

  13. Complement evasion by Borrelia burgdorferi: it takes three to tango

    NARCIS (Netherlands)

    de Taeye, Steven W.; Kreuk, Lieselotte; van Dam, Alje P.; Hovius, Joppe W.; Schuijt, Tim J.

    2013-01-01

    The complement system is one of the major innate defense mechanisms Borrelia burgdorferi sensu lato has to overcome to establish an infection of mammalian hosts and to cause Lyme borreliosis in humans. Borrelia prevents complement-mediated killing during host colonization through (i) recruitment of

  14. Molecular interplay between bacteria and the terminal complement pathway

    NARCIS (Netherlands)

    Berends, E.T.M.

    2015-01-01

    The plasma proteins of the complement system fulfill important immune defense functions, including opsonization of bacteria for phagocytosis, generation of chemo-attractants and direct bacterial killing via assembly of the Membrane Attack Complex (MAC or C5b-9 complex). The terminal complement

  15. Inactivation of complement by Loxosceles reclusa spider venom.

    Science.gov (United States)

    Gebel, H M; Finke, J H; Elgert, K D; Cambell, B J; Barrett, J T

    1979-07-01

    Zymosan depletion of serum complement in guinea pigs rendered them highly resistant to lesion by Loxosceles reclusa spider venom. Guinea pigs deficient in C4 of the complement system are as sensitive to the venom as normal guinea pigs. The injection of 35 micrograms of whole recluse venom intradermally into guinea pigs lowered their complement level by 35.7%. Brown recluse spider venom in concentrations as slight as 0.02 micrograms protein/ml can totally inactivate one CH50 of guinea pig complement in vitro. Bee, scorpion, and other spider venoms had no influence on the hemolytic titer of complement. Fractionation of recluse spider venom by Sephadex G-200 filtration separated the complement-inactivating property of the venom into three major regions which could be distinguished on the basis of heat stability as well as size. None was neutralized by antivenom. Polyacrylamide gel electrophoresis of venom resolved the complement inactivators into five fractions. Complement inactivated by whole venom or the Sephadex fractions could be restored to hemolytic activity by supplements of fresh serum but not by heat-inactivated serum, pure C3, pure C5, or C3 and C5 in combination.

  16. Production of complement components by cells of the immune system.

    Science.gov (United States)

    Lubbers, R; van Essen, M F; van Kooten, C; Trouw, L A

    2017-05-01

    The complement system is an important part of the innate immune defence. It contributes not only to local inflammation, removal and killing of pathogens, but it also assists in shaping of the adaptive immune response. Besides a role in inflammation, complement is also involved in physiological processes such as waste disposal and developmental programmes. The complement system comprises several soluble and membrane-bound proteins. The bulk of the soluble proteins is produced mainly by the liver. While several complement proteins are produced by a wide variety of cell types, other complement proteins are produced by only a few related cell types. As these data suggest that local production by specific cell types may have specific functions, more detailed studies have been employed recently analysing the local and even intracellular role of these complement proteins. Here we review the current knowledge about extrahepatic production and/or secretion of complement components. More specifically, we address what is known about complement synthesis by cells of the human immune system. © 2017 British Society for Immunology.

  17. Rat C-reactive protein activates the autologous complement system

    NARCIS (Netherlands)

    Diaz Padilla, Niubel; Bleeker, Wim K.; Lubbers, Yvonne; Rigter, Gemma M. M.; van Mierlo, Gerard J.; Daha, Mohamed R.; Hack, C. Erik

    2003-01-01

    Activation of complement is a biological function of human C-reactive protein (hCRP), whereas rat CRP (rCRP) has been claimed to be unable to activate complement. As important biological functions of proteins are probably conserved among species, we re-evaluated, using various ligands, the

  18. Complement Attack against Aspergillus and Corresponding Evasion Mechanisms

    Science.gov (United States)

    Speth, Cornelia; Rambach, Günter

    2012-01-01

    Invasive aspergillosis shows a high mortality rate particularly in immunocompromised patients. Perpetually increasing numbers of affected patients highlight the importance of a clearer understanding of interactions between innate immunity and fungi. Innate immunity is considered to be the most significant host defence against invasive fungal infections. Complement represents a crucial part of this first line defence and comprises direct effects against invading pathogens as well as bridging functions to other parts of the immune network. However, despite the potency of complement to attack foreign pathogens, the prevalence of invasive fungal infections is increasing. Two possible reasons may explain that phenomenon: First, complement activation might be insufficient for an effective antifungal defence in risk patients (due to, e.g., low complement levels, poor recognition of fungal surface, or missing interplay with other immune elements in immunocompromised patients). On the other hand, fungi may have developed evasion strategies to avoid recognition and/or eradication by complement. In this review, we summarize the most important interactions between Aspergillus and the complement system. We describe the various ways of complement activation by Aspergillus and the antifungal effects of the system, and also show proven and probable mechanisms of Aspergillus for complement evasion. PMID:22927844

  19. Schur complements of matrices with acyclic bipartite graphs

    DEFF Research Database (Denmark)

    Britz, Thomas Johann; Olesky, D.D.; van den Driessche, P.

    2005-01-01

    Bipartite graphs are used to describe the generalized Schur complements of real matrices having nos quare submatrix with two or more nonzero diagonals. For any matrix A with this property, including any nearly reducible matrix, the sign pattern of each generalized Schur complement is shown...

  20. Inhibition of the Membrane Attack Complex by Dengue Virus NS1 through Interaction with Vitronectin and Terminal Complement Proteins.

    Science.gov (United States)

    Conde, Jonas Nascimento; da Silva, Emiliana Mandarano; Allonso, Diego; Coelho, Diego Rodrigues; Andrade, Iamara da Silva; de Medeiros, Luciano Neves; Menezes, Joice Lima; Barbosa, Angela Silva; Mohana-Borges, Ronaldo

    2016-11-01

    Dengue virus (DENV) infects millions of people worldwide and is a major public health problem. DENV nonstructural protein 1 (NS1) is a conserved glycoprotein that associates with membranes and is also secreted into the plasma in DENV-infected patients. The present study describes a novel mechanism by which NS1 inhibits the terminal complement pathway. We first identified the terminal complement regulator vitronectin (VN) as a novel DENV2 NS1 binding partner by using a yeast two-hybrid system. This interaction was further assessed by enzyme-linked immunosorbent assay (ELISA) and surface plasmon resonance (SPR) assay. The NS1-VN complex was also detected in plasmas from DENV-infected patients, suggesting that this interaction occurs during DENV infection. We also demonstrated that the DENV2 NS1 protein, either by itself or by interacting with VN, hinders the formation of the membrane attack complex (MAC) and C9 polymerization. Finally, we showed that DENV2, West Nile virus (WNV), and Zika virus (ZIKV) NS1 proteins produced in mammalian cells inhibited C9 polymerization. Taken together, our results points to a role for NS1 as a terminal pathway inhibitor of the complement system. Dengue is the most important arthropod-borne viral disease nowadays and is caused by dengue virus (DENV). The flavivirus NS1 glycoprotein has been characterized functionally as a complement evasion protein that can attenuate the activation of the classical, lectin, and alternative pathways. The present study describes a novel mechanism by which DENV NS1 inhibits the terminal complement pathway. We identified the terminal complement regulator vitronectin (VN) as a novel DENV NS1 binding partner, and the NS1-VN complex was detected in plasmas from DENV-infected patients, suggesting that this interaction occurs during DENV infection. We also demonstrated that the NS1-VN complex inhibited membrane attack complex (MAC) formation, thus interfering with the complement terminal pathway. Interestingly

  1. 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.

  2. [The complement system: a double edge sword in tumor progression].

    Science.gov (United States)

    Daugan, Marie; Noe, Remi; Herman Fridman, Wolf; Sautes-Fridman, Catherine; Roumenina, Lubka T

    2017-10-01

    The complement system is a key component of the innate immunity, playing a role in pathogen elimination and in host homeostasis. The complement system has been considered for long time as an anti-tumoral element. However, recent studies showed a pro-tumoral effect of complement and particularly of the anaphylatoxines C3a and C5a in a large variety of tumor types. Complement proteins act on different levels of tumor progression, affecting the tumor cells, the angiogenesis and the immune microenvironment. The impact of the complement system on tumor progression seems to be cancer type-dependent and this has to be taken into account in the establishment of potential biomarkers and development of therapeutic strategies. © 2017 médecine/sciences – Inserm.

  3. Complement monitoring of Pluronic 127 gel and micelles

    DEFF Research Database (Denmark)

    Hamad, Islam; Hunter, A Christy; Moghimi, Seyed Moien

    2013-01-01

    vascular occlusion. We show that poloxamer gel can trigger the complement system, which is an integral part of innate immunity and its inadvertent activation can induce clinically significant anaphylaxis. Complement activation by the poloxamer gel is through the alternative pathway, but material...... transformations from gel to the solution state further incite complement through calcium-sensitive pathways, where a role for C1q and antibodies has been eliminated. Poloxamer addition to plasma/serum (at levels above its critical micelle concentration, cmc) induced formation of large and diffused structures......, which may have been responsible for triggering complement. Since poloxamer 407 administration has been reported to cause significant changes in plasma cholesterol and triglyceride levels we further examined the role of lipoproteins in poloxamer-mediated complement activation. Our results show...

  4. Cysteine proteinase from Streptococcus pyogenes enables evasion of innate immunity via degradation of complement factors.

    Science.gov (United States)

    Honda-Ogawa, Mariko; Ogawa, Taiji; Terao, Yutaka; Sumitomo, Tomoko; Nakata, Masanobu; Ikebe, Kazunori; Maeda, Yoshinobu; Kawabata, Shigetada

    2013-05-31

    Streptococcus pyogenes is an important human pathogen that causes invasive diseases such as necrotizing fasciitis, sepsis, and streptococcal toxic shock syndrome. We investigated the function of a major cysteine protease from S. pyogenes that affects the amount of C1-esterase inhibitor (C1-INH) and other complement factors and aimed to elucidate the mechanism involved in occurrence of streptococcal toxic shock syndrome from the aspect of the complement system. First, we revealed that culture supernatant of a given S. pyogenes strain and recombinant SpeB degraded the C1-INH. Then, we determined the N-terminal sequence of the C1-INH fragment degraded by recombinant SpeB. Interestingly, the region containing one of the identified cleavage sites is not present in patients with C1-INH deficiency. Scanning electron microscopy of the speB mutant incubated in human serum showed the abnormal superficial architecture and irregular oval structure. Furthermore, unlike the wild-type strain, that mutant strain showed lower survival capacity than normal as compared with heat-inactivated serum, whereas it had a significantly higher survival rate in serum without the C1-INH than in normal serum. Also, SpeB degraded multiple complement factors and the membrane attack complex. Flow cytometric analyses revealed deposition of C9, one of the components of membrane the attack complex, in greater amounts on the surface of the speB mutant, whereas lower amounts of C9 were bound to the wild-type strain surface. These results suggest that SpeB can interrupt the human complement system via degrading the C1-INH, thus enabling S. pyogenes to evade eradication in a hostile environment.

  5. 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...

  6. Complement in Non-Antibody-Mediated Kidney Diseases

    Directory of Open Access Journals (Sweden)

    Andrea Angeletti

    2017-07-01

    Full Text Available The complement system is part of the innate immune response that plays important roles in protecting the host from foreign pathogens. The complement components and relative fragment deposition have long been recognized to be strongly involved also in the pathogenesis of autoantibody-related kidney glomerulopathies, leading to direct glomerular injury and recruitment of infiltrating inflammation pathways. More recently, unregulated complement activation has been shown to be associated with progression of non-antibody-mediated kidney diseases, including focal segmental glomerulosclerosis, C3 glomerular disease, thrombotic microangiopathies, or general fibrosis generation in progressive chronic kidney diseases. Some of the specific mechanisms associated with complement activation in these diseases were recently clarified, showing a dominant role of alternative activation pathway. Over the last decade, a growing number of anticomplement agents have been developed, and some of them are being approved for clinical use or already in use. Therefore, anticomplement therapies represent a realistic choice of therapeutic approaches for complement-related diseases. Herein, we review the complement system activation, regulatory mechanisms, their involvement in non-antibody-mediated glomerular diseases, and the recent advances in complement-targeting agents as potential therapeutic strategies.

  7. Complement in disease: a defence system turning offensive.

    Science.gov (United States)

    Ricklin, Daniel; Reis, Edimara S; Lambris, John D

    2016-07-01

    Although the complement system is primarily perceived as a host defence system, a more versatile, yet potentially more harmful side of this innate immune pathway as an inflammatory mediator also exists. The activities that define the ability of the complement system to control microbial threats and eliminate cellular debris - such as sensing molecular danger patterns, generating immediate effectors, and extensively coordinating with other defence pathways - can quickly turn complement from a defence system to an aggressor that drives immune and inflammatory diseases. These host-offensive actions become more pronounced with age and are exacerbated by a variety of genetic factors and autoimmune responses. Complement can also be activated inappropriately, for example in response to biomaterials or transplants. A wealth of research over the past two decades has led to an increasingly finely tuned understanding of complement activation, identified tipping points between physiological and pathological behaviour, and revealed avenues for therapeutic intervention. This Review summarizes our current view of the key activating, regulatory, and effector mechanisms of the complement system, highlighting important crosstalk connections, and, with an emphasis on kidney disease and transplantation, discusses the involvement of complement in clinical conditions and promising therapeutic approaches.

  8. Intracellular complement - the complosome - in immune cell regulation.

    Science.gov (United States)

    Arbore, Giuseppina; Kemper, Claudia; Kolev, Martin

    2017-09-01

    The complement system was defined over a century ago based on its ability to "complement" the antibody-mediated and cell-mediated immune responses against pathogens. Today our understanding of this ancient part of innate immunity has changed substantially and we know now that complement plays an undisputed pivotal role in the regulation of both innate and adaptive immunity. The complement system consists of over 50 blood-circulating, cell-surface expressed and intracellular proteins. It is key in the recognition and elimination of invading pathogens, also in the removal of self-derived danger such as apoptotic cells, and it supports innate immune responses and the initiation of the general inflammatory reactions. The long prevailing classic view of complement was that of a serum-operative danger sensor and first line of defence system, however, recent experimental and clinical evidences have demonstrated that "local" tissue and surprisingly intracellular complement (the complosome) activation impacts on normal cell physiology. This review will focus on novel aspects of intracellular complement activation and its unexpected roles in basic cell processes such as metabolism. We also discuss what the existence of the complosome potentially means for how the host handles intracellular pathogens such as viruses. Copyright © 2017. Published by Elsevier Ltd.

  9. Temporal specification and subject reference in Romanian subjunctive complements

    Directory of Open Access Journals (Sweden)

    Maria Aurelia Cotfas

    2009-01-01

    Full Text Available The paper looks at the dependency of Romanian subjunctive complements on the semantic class of the matrix verb. It shows that different types of temporal dependency trigger different identity relations between the null embedded subject and the (subject antecedent in the main clause (cf. Farkas 1984. Volitional verbs are also looked at in terms of the restrictions they impose on the subjunctive complements they subcategorize for. Finally, following Landau’s (1999 classification of infinitive complements in English, Romanian subjunctives are argued to fall into two distinct classses exhibiting different properties in terms of subject reference and temporal dependency.

  10. The role of the complement system in diabetic nephropathy

    DEFF Research Database (Denmark)

    Flyvbjerg, Allan

    2017-01-01

    -threatening disease. An increasing body of evidence points toward a role of the complement system in the pathogenesis of diabetic nephropathy. For example, circulating levels of mannose-binding lectin (MBL), a pattern recognition molecule of the innate immune system, have emerged as a robust biomarker...... for the development and progression of this disease, and evidence suggests that MBL, H-ficolin, complement component C3 and the membrane attack complex might contribute to renal injury in the hyperglycaemic mileu. New approaches to modulate the complement system might lead to the development of new agents to prevent...

  11. LDL apheresis activates the complement system and the cytokine network, whereas PCSK9 inhibition with evolocumab induces no inflammatory response.

    Science.gov (United States)

    Lappegård, Knut Tore; Enebakk, Terje; Thunhaug, Hilde; Ludviksen, Judith Krey; Mollnes, Tom Eirik; Hovland, Anders

    Low-density lipoprotein (LDL) apheresis is an extracorporeal treatment modality used in high-risk coronary patients. It may, however, induce complement activation and downstream inflammation due to bio-incompatibility. We explored changes in soluble inflammatory markers when changing from LDL apheresis to the novel PCSK9 inhibitor evolocumab. Three patients with familial hypercholesterolemia participated. Blood samples (EDTA plasma) for complement activation and markers of inflammation were obtained before (baseline) and after LDL apheresis week at 0 and before biweekly administration of evolocumab at weeks 1, 3, 5, and 7. Complement activation was measured by ELISA and cytokines by multiplex technology. Complement activation products C3a and Bb were both significantly higher after LDL apheresis compared to baseline (P = .01), returned to baseline levels before administration of evolocumab and remained low through week 7. C4d was unchanged during LDL apheresis, whereas TCC was slightly higher after apheresis compared to baseline and week 7 without statistical difference. MCP-1 was higher after LDL apheresis compared to baseline (P = .04), returned to baseline levels before administration of evolocumab and remained low through week 7. There were minor changes for other cytokines including TNF, IFN-γ, MIP-1α, MIP-1β, with some higher and some lower after apheresis; however, none of these changes were statistically significant. Fibrinogen and CRP were lower after LDL apheresis and had returned to levels comparable to baseline at week 7, statistically significant however only for fibrinogen. LDL apheresis activated the alternative complement system significantly as reflected by an increase in C3a and Bb. PCSK9 inhibition did not affect complement or cytokines during 7 weeks follow-up. Copyright © 2016 National Lipid Association. Published by Elsevier Inc. All rights reserved.

  12. A serine protease isolated from the bristles of the Amazonic caterpillar, Premolis semirufa, is a potent complement system activator.

    Directory of Open Access Journals (Sweden)

    Isadora Maria Villas Boas

    Full Text Available The caterpillar of the moth Premolis semirufa, commonly named pararama, is found in the Brazilian Amazon region. Accidental contact with the caterpillar bristles causes an intense itching sensation, followed by symptoms of an acute inflammation, which last for three to seven days after the first incident. After multiple accidents a chronic inflammatory reaction, called "Pararamose", characterized by articular synovial membrane thickening with joint deformities common to chronic synovitis, frequently occurs. Although complement mediated inflammation may aid the host defense, inappropriate or excessive activation of the complement system and generation of anaphylatoxins can lead to inflammatory disorder and pathologies. The aim of the present study was to evaluate, in vitro, whether the Premolis semirufa's bristles extract could interfere with the human complement system.The bristles extract was able to inhibit the haemolytic activity of the alternative pathway, as well as the activation of the lectin pathway, but had no effect on the classical pathway, and this inhibition seemed to be caused by activation and consumption of complement components. The extract induced the production of significant amounts of all three anaphylatoxins, C3a, C4a and C5a, promoted direct cleavage of C3, C4 and C5 and induced a significant generation of terminal complement complexes in normal human serum. By using molecular exclusion chromatography, a serine protease of 82 kDa, which activates complement, was isolated from P. semirufa bristles extract. The protease, named here as Ps82, reduced the haemolytic activity of the alternative and classical pathways and inhibited the lectin pathway. In addition, Ps82 induced the cleavage of C3, C4 and C5 and the generation of C3a and C4a in normal human serum and it was capable to cleave human purified C5 and generate C5a. The use of Phenanthroline, metalloprotease inhibitor, in the reactions did not significantly interfere

  13. Complement system activation in ANCA vasculitis : A translational success story?

    NARCIS (Netherlands)

    Kallenberg, Cees G. M.; Heeringa, Peter

    2015-01-01

    The ANCA-associated vasculitides (AAV) are characterized by pauci-immune necrotizing small to medium size vessel vasculitis frequently including necrotizing crescentric glomerulonephritis. Neutrophil activation by ANCA appears a primary pathogenic event. More recently, the complement system has been

  14. The Role of the Complement System in Acute Kidney Injury

    Science.gov (United States)

    McCullough, James W.; Renner, Brandon; Thurman, Joshua M.

    2013-01-01

    Summary Acute kidney injury is a common and severe clinical problem. Patients who develop acute kidney injury are at increased risk of death in spite of supportive measures such as hemodialysis. Research in recent years has revealed that tissue inflammation is central to the pathogenesis of renal injury, even after non-immune insults such as ischemia/reperfusion and toxins. Examination of clinical samples and pre-clinical models demonstrate that activation of the complement system is a critical cause of acute kidney injury. Furthermore, complement activation within the injured kidney is a proximal trigger of many downstream inflammatory events within the renal parenchyma that exacerbate injury to the kidney. Complement activation may also account for the systemic inflammatory events that contribute to remote organ injury and patient mortality. Complement inhibitory drugs have now entered clinical use and may provide an important new therapeutic approach for patients suffering from or at high risk of developing acute kidney injury. PMID:24161039

  15. Complement C4 phenotypes in dementia of the Alzheimer type

    NARCIS (Netherlands)

    Eikelenboom, P.; Goetz, J.; Pronk, J. C.; Hauptmann, G.

    1988-01-01

    Complement C4 phenotype distribution was studied in 64 patients with dementia of the Alzheimer type. In contrast to reported findings we failed to find a significant association between C4B2 gene frequency and Alzheimer's dementia

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

    Science.gov (United States)

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

    2016-09-01

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

  17. Complement titration by rectilinear attenuance and attempts at its automatization

    Science.gov (United States)

    Satoh, P. S.; Yoshida, T. O.; Fukusima, Y.; Ono, N.; Yoshida, K.; Ito, Y.

    1969-01-01

    Immune haemolysis was determined by rectilinear attenuance at 625 mμ (l = 1.3 mm, 1.25 mm), and the data obtained treated by von Krogh's empirical equation. The C′H50/ml values obtained by the attenuance method had high correlation with those obtained by the conventional photometric method (541 mμ). Automatic complement titration was attempted, as a part of the basic studies on quantitative complement fixation tests. PMID:5386637

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    , IR was an independent predictor of sMAC in the CHF group beta = 0.37 (p complement system and thus......Objectives. Patients with chronic heart failure (CHF) have an exaggerated immune response, endothelial damage/dysfunction, and increased risk of diabetes mellitus (DM). The inter-relationship(s) between indices of complement activation (soluble membrane attack complex, sMAC), inflammation (hs...

  19. Depletion of complement system immunity in patients with myocardial infarction.

    Science.gov (United States)

    Yan, Wenwen; Che, Lin; Jiang, Jinfa; Yang, Fan; Duan, Qianglin; Song, Haoming; Liu, Xiaohong; Shen, Yuqin; Wang, Lemin

    2016-12-01

    The aim of the present study was to evaluate differences in the expression of complement system genes, and serum levels of CH50, C3 and C4 in peripheral blood mononuclear cells from patients with myocardial infarction (AMI), stable angina pectoris (SA) and controls. A total of 100 patients with AMI, 100 with SA and 100 clinical controls were recruited in the present study. In each group, 20 randomly selected individuals were examined using whole human genome microarray analysis to detect the expression of genes of the complement system. The serum levels of CH50, C3 and C4 were measured in all 300 subjects. In the patients with AMI, the expression levels of genes encoding C1qα, C1qβ, C1qγ, C1r, Factor P, C5a (complement component), CR1, integrin αM, integrin αX, integrin β2, C5aR, CRIg (complement receptors) and CD46, CD55 and CD59 (complement regulators) were significantly higher, compared with the respective genes in the SA patients and controls (Pcomplement components or regulators between the SA and control groups. The serum levels of CH50, C3 and C4 were significantly increased in the AMI and SA groups, compared with the controls. In the AMI and SA groups, the complement system was activated. However, the differential mRNA expression of complement components, receptors and regulators in the AMI group suggested the dysfunction of the C5b-9 complex. The depression of complement system immunity in the patients with AMI may be associated with the pathogenesis of AMI.

  20. The versatile functions of complement C3-derived ligands.

    Science.gov (United States)

    Erdei, Anna; Sándor, Noémi; Mácsik-Valent, Bernadett; Lukácsi, Szilvia; Kremlitzka, Mariann; Bajtay, Zsuzsa

    2016-11-01

    The complement system is a major component of immune defense. Activation of the complement cascade by foreign substances and altered self-structures may lead to the elimination of the activating agent, and during the enzymatic cascade, several biologically active fragments are generated. Most immune regulatory effects of complement are mediated by the activation products of C3, the central component. The indispensable role of C3 in opsonic phagocytosis as well as in the regulation of humoral immune response is known for long, while the involvement of complement in T-cell biology have been revealed in the past few years. In this review, we discuss the immune modulatory functions of C3-derived fragments focusing on their role in processes which have not been summarized so far. The importance of locally synthesized complement will receive special emphasis, as several immunological processes take place in tissues, where hepatocyte-derived complement components might not be available at high concentrations. We also aim to call the attention to important differences between human and mouse systems regarding C3-mediated processes. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. 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.

  2. Exploitation of complement regulatory proteins by Borrelia and Francisella.

    Science.gov (United States)

    Madar, Marian; Bencurova, Elena; Mlynarcik, Patrik; Almeida, André M; Soares, Renata; Bhide, Katarina; Pulzova, Lucia; Kovac, Andrej; Coelho, Ana V; Bhide, Mangesh

    2015-06-01

    Pathogens have developed sophisticated mechanisms of complement evasion such as binding to the host complement regulatory proteins (CRPs) on their surface or expression of CRP mimicking molecules. The ability of pathogens to evade the complement system has been correlated with pathogenesis and host selectivity. Hitherto, little work has been undertaken to determine whether Borrelia and Francisella exploit various CRPs to block complement attack. Seventeen Borrelia (twelve species) and six Francisella (three subspecies) strains were used to assess their ability to bind human, sheep and cattle CRPs or mimic membrane associated complement regulators. A series of experiments including affinity ligand binding experiments, pull-down assays and mass spectrometry based protein identification, revealed an array of CRP binding proteins of Borrelia and Francisella. Unlike Francisella, Borrelia strains were able to bind multiple human CRPs. Three strains of Borrelia (SKT-4, SKT-2 and HO14) showed the presence of a human CD46-homologous motif, indicating their ability to possess putative human CD46 mimicking molecules. Similarly, five strains of Borrelia and two strains of Francisella may have surface proteins with human CD59-homologous motifs. Among ovine and bovine CRPs, the only CRP bound by Francisella (LVS, Tul4 strain) was vitronectin, while ovine C4BP, ovine factor H and bovine factor H were bound to Borrelia strains SKT-2, DN127 and Co53. This study presents an array of proteins of Borrelia and Francisella that bind CRPs or may mimic membrane-CRPs, thus enabling multiphasic complement evasion strategies of these pathogens.

  3. On the Status of the Complementizer WAA6 in Cantonese

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    Ka-Wai Yeung

    2006-06-01

    Full Text Available Complementizers are generally known as function words that introduce a clausal complement, like that in English, for instance (Radford 1997. In many languages, complementizers are re-analyzed from verba dicendi, or verbs of ‘saying’ (Lord 1976; Frajzyngier 1991; Hopper and Traugott 1993; Lord 1993. This paper argues for the existence of a complementizer re-analyzed from a verb of ‘saying’ in Cantonese by providing a synchronic analysis for waa6. Waa6 has often been assumed to be a lexical verb in serial verb construction because of its following a ‘saying’ predicate or a cognitive predicate. However, this paper argues that waa6 is not always a verb, postulating that waa6 may have different meanings and subcategorizations in different situations, including waa61 meaning ‘say’ [__ (PP CP] or {__PP NP}, the transitive verb waa62 meaning ‘blame/condemn’ [__NP CP], and the complementizer waa63 selecting a clause [__ IP]. This proposal is supported by different tests, such as aspect marking and argument selection, confirming that the complementizer waa63 formally exhibits different properties from that of the verbs waa61 and waa62.

  4. Alpha glucosidase inhibitors

    National Research Council Canada - National Science Library

    Kalra, Sanjay

    2014-01-01

    Alpha glucosidase inhibitors (AGIs) are a unique class of anti-diabetic drugs. Derived from bacteria, these oral drugs are enzyme inhibitors which do not have a pancreato -centred mechanism of action...

  5. Proton pump inhibitors

    Science.gov (United States)

    Proton pump inhibitors (PPIs) are medicines that work by reducing the amount of stomach acid made by glands in ... Proton pump inhibitors are used to: Relieve symptoms of acid reflux, or gastroesophageal reflux disease (GERD). This is a ...

  6. 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 the rearrangement accompanying C4 cleavage and suggest intramolecular flexibility of C4b. The conformations of C4b and its paralogue C3b are shown to be remarkably conserved, suggesting that the convertases from the classical and alternative pathways are likely to share their overall architecture and mode...

  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 normal B cells are capable of activating the alternative pathway (AP) of complement in a CR2-dependent fashion. In this study we have investigated whether disturbances in this activity may be related to the altered phenotype of SLE B cells. Flow cytometry was used to measure expression of complement...... activation by B cells in homologous serum. Finally, we demonstrated an inverse relationship between SLE disease activity index (SLEDAI) and the expression of complement receptor 2 (CR2) on SLE B cells. Thus, determination of CR2 on B cells may emerge as an additional laboratory tool in the assessment of SLE...

  8. Cigarette smoke can activate the alternative pathway of complement in vitro by modifying the third component of complement.

    OpenAIRE

    Kew, R R; Ghebrehiwet, B; Janoff, A

    1985-01-01

    Cigarette smoking is associated with significant increases in the number of pulmonary mononuclear phagocytes and neutrophils. A potent chemoattractant for these cells is C5a, a peptide generated during complement (C) activation. We, therefore, investigated the possibility that cigarette smoke could activate the complement system in vitro. Our results show that factor(s) (mol wt less than 1,000) present in an aqueous solution of whole, unfiltered cigarette smoke can deplete the hemolytic capac...

  9. Mesenchymal stem cells engineered to inhibit complement-mediated damage.

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    Melisa A Soland

    Full Text Available Mesenchymal stem cells (MSC preferentially migrate to damaged tissues and, due to their immunomodulatory and trophic properties, contribute to tissue repair. Although MSC express molecules, such as membrane cofactor protein (CD46, complement decay-accelerating factor (CD55, and protectin (CD59, which confer protection from complement-mediated lysis, MSC are recruited and activated by anaphylatoxins after transplantation, potentially causing MSC death and limiting therapeutic benefit. We have previously demonstrated that transduction of MSC with a retrovirus encoding HCMV-US proteins resulted in higher levels of MSC engraftment due to decreased HLA-I expression. Here, we investigate whether engineering MSC to express US2 (MSC-US2, US3 (MSC-US3, US6 (MSC-US6, or US11 (MSC-US11 HCMV proteins can alter complement recognition, thereby better protecting MSC from complement attack and lysis. HCMV-US proteins increased MSC CD59 expression at different levels as determined by flow cytometric evaluation of the median fluorescence intensity ratio (MFI. A significant increase in CD59 expression was seen in MSC-US2, MSC-US3, and MSC-US6, but not in MSC-US11. Only MSC-US2 displayed increased expression of CD46, while US2 and US3 proteins were both able to augment the percentage of MSC expressing this molecule. Regardless of the HCMV protein expressed, none changed CD55 MFI; however, expression of US6, US11, and US2 each increased the percentage of MSC that were positive for this molecule. Because US2 protein was the most efficient in up-regulating all three complement regulatory proteins, we used a functional complement-mediated cytotoxicity assay to investigate whether MSC-US2 were protected from complement-mediated lysis. We demonstrated that over-expression of the US2 protein reduced complement lysis by 59.10±12.89% when compared to untransduced MSC. This is the first report, to our knowledge, describing a role of HCMV-US proteins in complement evasion

  10. Conformational states of a bacterial α2-macroglobulin resemble those of human complement C3.

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    David Neves

    Full Text Available α(2 macroglobulins (α(2Ms are broad-spectrum protease inhibitors that play essential roles in the innate immune system of eukaryotic species. These large, multi-domain proteins are characterized by a broad-spectrum bait region and an internal thioester, which, upon cleavage, becomes covalently associated to the target protease, allowing its entrapment by a large conformational modification. Notably, α(2Ms are part of a larger protein superfamily that includes proteins of the complement system, such as C3, a multi-domain macromolecule which is also characterized by an internal thioester-carrying domain and whose activation represents the pivotal step in the complement cascade. Recently, α(2M/C3-like genes were identified in a large number of bacterial genomes, and the Escherichia coli α(2M homolog (ECAM was shown to be activated by proteases. In this work, we have structurally characterized ECAM by electron microscopy and small angle scattering (SAXS techniques. ECAM is an elongated, flexible molecule with overall similarities to C3 in its inactive form; activation by methylamine, chymotrypsin, or elastase induces a conformational modification reminiscent of the one undergone by the transformation of C3 into its active form, C3b. In addition, the proposed C-terminus of ECAM displays high flexibility and different conformations, and could be the recognition site for partner macromolecules. This work sheds light on a potential bacterial defense mechanism that mimics structural rearrangements essential for activation of the complement cascade in eukaryotes, and represents a possible novel target for the development of antibacterials.

  11. Genetic engineering strategies to prevent the effects of antibody and complement on xenogeneic chondrocytes.

    Science.gov (United States)

    Sommaggio, R; Bello-Gil, D; Pérez-Cruz, M; Brokaw, J L; Máñez, R; Costa, C

    2015-11-18

    Advances in animal transgenesis may allow using xenogeneic chondrocytes in tissue-engineering applications for clinical cartilage repair. Porcine cartilage is rejected by humoral and cellular mechanisms that could be overcome by identifying key molecules triggering rejection and developing effective genetic-engineering strategies. Accordingly, high expression of α1,2-fucosyltransferase (HT) in xenogeneic cartilage protects from galactose α1,3-galactose (Gal)-mediated antibody responses. Now, we studied whether expression of a complement inhibitor provides further protection. First, porcine articular chondrocytes (PAC) were isolated from non-transgenic, single and double transgenic pigs expressing HT and moderate levels of human CD59 (hCD59) and their response to human serum was assessed. High recombinant expression of human complement regulatory molecules hCD59 and hDAF was also attained by retroviral transduction of PAC for further analyses. Complement activation on PAC after exposure to 20 % human serum for 24 hours mainly triggered the release of pro-inflammatory cytokines IL-6 and IL-8. Transgenic expression of HT and hCD59 did not suffice to fully counteract this effect. Nevertheless, the combination of blocking anti-Gal antibodies (or C5a) and high hCD59 levels conferred very high protection. On the contrary, high hDAF expression attained the most dramatic reduction in IL-6/IL-8 secretion by a single strategy, but the additional inhibition of anti-Gal antibodies or C5a did not provide further improvement. Notably, we demonstrate that both hCD59 and hDAF inhibit anaphylatoxin release in this setting. In conclusion, our study identifies genetic-engineering approaches to prevent humoral rejection of xenogeneic chondrocytes for use in cartilage repair.

  12. 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.

  13. Effects of Streptococcus pneumoniae strain background on complement resistance.

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    Catherine Hyams

    Full Text Available BACKGROUND: Immunity to infections caused by Streptococcus pneumoniae is dependent on complement. There are wide variations in sensitivity to complement between S. pneumoniae strains that could affect their ability to cause invasive infections. Although capsular serotype is one important factor causing differences in complement resistance between strains, there is also considerable other genetic variation between S. pneumoniae strains that may affect complement-mediated immunity. We have therefore investigated whether genetically distinct S. pneumoniae strains with the same capsular serotype vary in their sensitivity to complement mediated immunity. METHODOLOGY AND PRINCIPAL FINDINGS: C3b/iC3b deposition and neutrophil association were measured using flow cytometry assays for S. pneumoniae strains with different genetic backgrounds for each of eight capsular serotypes. For some capsular serotypes there was marked variation in C3b/iC3b deposition between different strains that was independent of capsule thickness and correlated closely to susceptibility to neutrophil association. C3b/iC3b deposition results also correlated weakly with the degree of IgG binding to each strain. However, the binding of C1q (the first component of the classical pathway correlated more closely with C3b/iC3b deposition, and large differences remained in complement sensitivity between strains with the same capsular serotype in sera in which IgG had been cleaved with IdeS. CONCLUSIONS: These data demonstrate that bacterial factors independent of the capsule and recognition by IgG have strong effects on the susceptibility of S. pneumoniae to complement, and could therefore potentially account for some of the differences in virulence between strains.

  14. 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.

  15. Human skin mast cells express complement factors C3 and C5.

    Science.gov (United States)

    Fukuoka, Yoshihiro; Hite, Michelle R; Dellinger, Anthony L; Schwartz, Lawrence B

    2013-08-15

    We examine whether complement factor C3 or C5 is synthesized by human skin-derived mast cells and whether their synthesis is regulated by cytokines. C3 and C5 mRNAs were assessed by RT-PCR, and proteins by flow cytometry, confocal microscopy, Western blotting, and ELISA. C3 and C5 mRNAs were each expressed, and baseline protein levels/10(6) cultured mast cells were 0.9 and 0.8 ng, respectively, and located in the cytoplasm outside of secretory granules. C3 accumulated in mast cell culture medium over time and by 3 d reached a concentration of 9.4 ± 8.0 ng/ml, whereas C5 levels were not detectable (C5 remained undetectable. Importantly, treatment with TNF-α together with either IL-4 or IL-13 synergistically enhanced C3 (but not C5) production in culture medium by 9.8- or 7.1-fold, respectively. This synergy was blocked by attenuating the TNF-α pathway with neutralizing anti-TNF-α Ab, soluble TNFR, or an inhibitor of NF-κB, or by attenuating the IL-4/13 pathway with Jak family or Erk antagonists. Inhibitors of PI3K, Jnk, and p38 MAPK did not affect this synergy. Thus, human mast cells can produce and secrete C3, whereas β-tryptase can act on C3 to generate C3a and C3b, raising the likelihood that mast cells engage complement to modulate immunity and inflammation in vivo.

  16. Edwardsiella tarda Tunes Tricarboxylic Acid Cycle to Evade Complement-Mediated Killing

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    Zhi-xue Cheng

    2017-12-01

    Full Text Available Evasion of complement-mediated killing is a common phenotype for many different types of pathogens, but the mechanism is still poorly understood. Most of the clinic isolates of Edwardsiella tarda, an important pathogen infecting both of human and fish, are commonly found serum-resistant. To explore the potential mechanisms, we applied gas chromatography-mass spectrometry (GC-MS-based metabolomics approaches to profile the metabolomes of E. tarda EIB202 in the presence or absence of serum stress. We found that tricarboxylic acid (TCA cycle was greatly enhanced in the presence of serum. The quantitative real-time PCR (qRT-PCR and enzyme activity assays validated this result. Furthermore, exogenous succinate that promotes the TCA cycle increased serum resistance, while TCA cycle inhibitors (bromopyruvate and propanedioic acid that inhibit TCA cycle, attenuated serum resistance. Moreover, the enhanced TCA cycle increased membrane potential, thus decreased the formation of membrane attack complex at cell surface, resulting serum resistance. These evidences suggested a previously unknown membrane potential-dependent mechanism of serum resistance. Therefore, our findings reveal that pathogen mounts a metabolic trick to cope with the serum complement-mediated killing.

  17. Complementation of arylsulfatase A in somatic hybrids of metachromatic leukodystrophy and multiple sulfatase deficiency disorder fibroblasts.

    Science.gov (United States)

    Chang, P L; Davidson, R G

    1980-10-01

    Metachromatic leukodystrophy and multiple sulfatase deficiency disorder are severe neurodegenerative diseases inherited as separate autosomal recessive traits. Arylsulfatase A (aryl-sulfate sulfohydrolase, EC 3.1.6.1) activity is deficient in both diseases but in multiple sulfatase deficiency disorder, activities of arylsulfatases B and C and other sulfatases are also reported to be reduced. Somatic hybrid cell clones produced by fusing cultured fibroblasts from patients with these diseases were isolated by a nonselective technique based on unit-gravity sedimentation. Arylsulfatase A activity was restored in these hybrids. The complemented enzyme resembled the normal arylsulfatase A in heat stability, pH optimum, Km, electrophoretic mobility, and immunologic reactivity. Because a structurally normal enzyme can be restored in a hybrid only though intergenic complementation, these results indicate that the mutations responsible for the deficiency of arylsulfatase A activity in metachromatic leukodystrophy and multiple sulfatase deficiency disorder are nonallelic and that at least two genetic loci control the expression of arylsulfatase A activity in the human genome. Furthermore, arylsulfatase C activity was also restored to normal in the hybrids, indicating that a common sulfatase inhibitor is not the cause of the multiple sulfatse deficiency.

  18. Mutations participating in interallelic complementation in propionic acidemia

    Energy Technology Data Exchange (ETDEWEB)

    Gravel, R.A.; Akerman, B.R.; Lamhonwah, A.M.; Loyer, M.; Leon-del-Rio, A.; Italiano, I. (McGill Univ., Montreal (Canada))

    1994-07-01

    Deficiency of propionyl-CoA carboxylase (PCC; [alpha][sub 4][beta][sub 4]) results in the rare, autosomal recessive disease propionic acidemia. Cell fusion experiments have revealed two complementation groups, pccA and pccB, corresponding to defects of the PCCA ([alpha]-subunit) and PCCB ([beta]-subunit) genes, respectively. The pccBCC group includes subgroups, pccB and pccC, which are thought to reflect interallelic complementation between certain mutations of the PCCB gene. In this study, the authors have identified the mutations in two pccB, one pccC, and two pccBC cell lines and have deduced those alleles participating in interallelic complementation. One pccB line was a compound hetrozygote of Pro228Leu and Asn536Asp. The latter mutation was also detected in a noncomplementing pccBC line. This leaves Pro228Leu responsible for complementation in the pccB cells. The second pccB line contained an insertional duplication, dupKICK140-143, and a splice mutation IVS+1 G[yields]T, located after Lys466. The authors suggest that the dupKICK mutation is the complementing allele, since the second allele is incompatible with normal splicing. The pccC line studied was homozygous for Arg410Trp, which is necessarily the complementing allele in that line. For a second pccC line, they previously had proposed that [Delta]Ile408 was the complementing allele. They now show that its second allele, [open quotes]Ins[center dot]Del[close quotes], a 14-bp deletion replaced by a 12-bp insertion beginning at codon 407, fails to complement in homozygous form. The authors conclude that the interallelic complementation results from mutations in domains that can interact between [beta]-subunits in the PCC heteromer to restore enzymatic function. On the basis of sequence homology with the Propionibacterium shermanii transcarboxylase 12S subunit, they suggest that the pccC domain, defined by Ile408 and Arg410, may involve the propionyl-CoA binding site. 37 refs., 5 figs., 2 tabs.

  19. Physicochemical signatures of nanoparticle-dependent complement activation

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-03-21

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

  20. Complement C3c as a Biomarker in Heart Failure

    Directory of Open Access Journals (Sweden)

    A. Frey

    2013-01-01

    Full Text Available Introduction. Experimental data indicates an important role of the innate immune system in cardiac remodeling and heart failure (HF. Complement is a central effector pathway of the innate immune system. Animals lacking parts of the complement system are protected from adverse remodeling. Based on these data, we hypothesized that peripheral complement levels could be a good marker for adverse remodeling and prognosis in patients with HF. Methods and Results. Since complement activation converges on the complement factor C3, we measured serum C3c, a stable C3-conversion product, in 197 patients with stable systolic HF. Subgroups with normal and elevated C3c levels were compared. C3c levels were elevated in 17% of the cohort. Patients with elevated C3c levels exhibited a trend to better survival, slightly higher LVEF, and lower NTpro-BNP values in comparison to patients with normal C3c values. No differences were found regarding NYHA functional class. Significantly more patients with elevated C3c had preexisting diabetes. The prevalence of CAD, arterial hypertension, and atrial fibrillation was not increased in patients with elevated C3c. Conclusion. Elevated C3c levels are associated with less adverse remodeling and improved survival in patients with stable systolic heart failure.

  1. Alternative complement pathway assessment in patients with atypical HUS.

    Science.gov (United States)

    Roumenina, Lubka T; Loirat, Chantal; Dragon-Durey, Marie-Agnes; Halbwachs-Mecarelli, Lise; Sautes-Fridman, Catherine; Fremeaux-Bacchi, Veronique

    2011-02-28

    The atypical Hemolytic Uremic Syndrome (aHUS) is a rare thrombotic microangiopathy leading to end stage renal disease in approximately 60% of patients. Over the last decade, a clear link has been demonstrated between this disease and defective complement regulation. The hallmark of the aHUS is the association with mutations in complement alternative pathway genes. Endothelial damage is related to complement dysregulation, but the exact mechanism is just starting to be elucidated. Screening for and characterization of mutations in the components of the C3 convertase (C3 and FB) or its regulators (FH, FI, MCP, and Thrombomodulin) or anti-FH antibodies has become an indispensable part of the disease's diagnostic. This review will initially summarize current knowledge on the understanding of complement activation and regulation, followed by a description on the genetic analysis as well as the methods used for complement protein quantification. Another part of this review will focus on the mechanisms of action of aHUS-associated mutations. We will emphasize on when and why some mutations lead to protein deficiency, while others result in - to dysfunctional but normally expressed proteins. Finally, we will discuss how the therapy of aHUS patients can be modified according to the functional consequences of each particular genetic defect. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Inhibition of complement activation by IgG4 antibodies.

    Science.gov (United States)

    van der Zee, J S; van Swieten, P; Aalberse, R C

    1986-05-01

    Prolonged exposure to antigens may result in high IgG4 antibody titres as was shown in a previous paper (Aalberse et al., 1983b). In novice bee keepers, a shift in the IgG1/IgG4 ratio of the response against phospholipase-A (PLA; a major component of bee venom) occurred. This resulted in an IgG4-dominated response after approximately 2 years of bee-keeping experience. Subject of the present study was the influence of relatively high concentrations of IgG4 antibodies on the biological activity of immune complexes. In the PLA antigen model, it was demonstrated that IgG4-containing immune complexes do not activate complement and that IgG4 antibodies effectively inhibit immune precipitation and complement activation by IgG1 antibodies. Evidence is provided that IgG4 antibodies inhibit binding of C1q to IgG1 in mixed, IgG1- and IgG4-containing complexes. It is proposed that IgG4 antibodies protect against the biological effects of the complement-fixing IgG subclasses. For this reason, determination of the total IgG response or just determination of antibody activity in the complement-fixing isotypes is insufficient in immune-complex diseases. The modulating effect of the non-complement-fixing isotypes should be taken into account to predict the biological activity of the immune complexes.

  3. Complement System in Neural Synapse Elimination in Development and Disease.

    Science.gov (United States)

    Presumey, Jessy; Bialas, Allison R; Carroll, Michael C

    2017-01-01

    Recent discoveries implicate the classical complement cascade in normal brain development and in disease. Complement proteins C1q, C3, and C4 participate in synapse elimination, tagging inappropriate synaptic connections between neurons for removal by phagocytic microglia that exist in a special, highly phagocytic state during the synaptic pruning period. Several neurodevelopmental disorders, such as schizophrenia and autism, are thought to be caused by an imbalance in synaptic pruning, and recent studies suggest that dysregulation of complement could promote this synaptic pruning imbalance. Moreover, in the mature brain, complement can be aberrantly activated in early stages of neurodegenerative diseases to stimulate synapse loss. Similar pathways can also be activated in response to inflammation, as in West Nile Virus infection or in lupus, where peripheral inflammation can promote microglia-mediated synapse loss. Whether synapse loss in disease is a true reactivation of developmental synaptic pruning programs remains unclear; nonetheless, complement proteins represent potential therapeutic targets for both neurodevelopmental and neurodegenerative diseases. © 2017 Elsevier Inc. All rights reserved.

  4. Cockayne syndrome complementation group B associated with xeroderma pigmentosum phenotype.

    Science.gov (United States)

    Itoh, T; Cleaver, J E; Yamaizumi, M

    1996-02-01

    Two siblings have been reported whose clinical manifestations (cutaneous photosensitivity and central nervous system dysfunction) are strongly reminiscent of the DeSanctis-Cacchione syndrome (DCS) variant of xeroderma pigmentosum (XP), a severe form of XP. Fibroblasts from the siblings showed UV sensitivity, a failure of recovery of RNA synthesis (RRS) after UV-irradiation, and a normal level of unscheduled DNA synthesis (UDS), which were, unexpectedly, the biochemical characteristics usually associated with Cockayne syndrome (CS). However, no complementation group assignment in these cells has yet been performed. We here report that these patients can be assigned to CS complementation group B (CSB) by cell fusion complementation analysis. To our knowledge, these are the first patients with defects in the CSB gene to be associated with an XP phenotype. The results imply that the gene product from the CSB gene must interact with the gene products involved in excision repair and associated with XP.

  5. Lessons learned from mice deficient in lectin complement pathway molecules

    DEFF Research Database (Denmark)

    Genster, Ninette; Takahashi, Minoru; Sekine, Hideharu

    2014-01-01

    The lectin pathway of the complement system is initiated when the pattern-recognition molecules, mannose-binding lectin (MBL), ficolins or collectin-11, bind to invading pathogens or damaged host cells. This leads to activation of MBL/ficolin/collectin-11 associated serine proteases (MASPs), which...... in turn activate downstream complement components, ultimately leading to elimination of the pathogen. Mice deficient in the key molecules of lectin pathway of complement have been generated in order to build knowledge of the molecular mechanisms of the lectin pathway in health and disease. Despite...... differences in the genetic arrangements of murine and human orthologues of lectin pathway molecules, the knockout mice have proven to be valuable models to explore the effect of deficiency states in humans. In addition, new insight and unexpected findings on the diverse roles of lectin pathway molecules...

  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. Quantitative Modeling of the Alternative Pathway of the Complement System.

    Science.gov (United States)

    Zewde, Nehemiah; Gorham, Ronald D; Dorado, Angel; Morikis, Dimitrios

    2016-01-01

    The complement system is an integral part of innate immunity that detects and eliminates invading pathogens through a cascade of reactions. The destructive effects of the complement activation on host cells are inhibited through versatile regulators that are present in plasma and bound to membranes. Impairment in the capacity of these regulators to function in the proper manner results in autoimmune diseases. To better understand the delicate balance between complement activation and regulation, we have developed a comprehensive quantitative model of the alternative pathway. Our model incorporates a system of ordinary differential equations that describes the dynamics of the four steps of the alternative pathway under physiological conditions: (i) initiation (fluid phase), (ii) amplification (surfaces), (iii) termination (pathogen), and (iv) regulation (host cell and fluid phase). We have examined complement activation and regulation on different surfaces, using the cellular dimensions of a characteristic bacterium (E. coli) and host cell (human erythrocyte). In addition, we have incorporated neutrophil-secreted properdin into the model highlighting the cross talk of neutrophils with the alternative pathway in coordinating innate immunity. Our study yields a series of time-dependent response data for all alternative pathway proteins, fragments, and complexes. We demonstrate the robustness of alternative pathway on the surface of pathogens in which complement components were able to saturate the entire region in about 54 minutes, while occupying less than one percent on host cells at the same time period. Our model reveals that tight regulation of complement starts in fluid phase in which propagation of the alternative pathway was inhibited through the dismantlement of fluid phase convertases. Our model also depicts the intricate role that properdin released from neutrophils plays in initiating and propagating the alternative pathway during bacterial infection.

  8. The Complement System: A Prey of Trypanosoma cruzi

    Science.gov (United States)

    Lidani, Kárita C. F.; Bavia, Lorena; Ambrosio, Altair R.; de Messias-Reason, Iara J.

    2017-01-01

    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 of plasma

  9. Multiple complementizers in Modern Danish and Middle English

    DEFF Research Database (Denmark)

    Nyvad, Anne Mette

    2016-01-01

    This paper expands the empirical coverage of the cP/CP-distinction proposed by Nyvad, Christensen & Vikner (2015) by applying it to a range of embedded clause types involving multiple complementizers in Middle English and Modern Danish, and offering a uniform analysis. Due to the fact that a number...... of the structures investigated do not violate the Doubly Filled COMP Filter, but involve multiple heads inside the CP-domain, the proposed CP-recursion analysis is an attempt to integrate more material into the CP-domain than a single X-bar projection level. Based on examples from adverbial clauses, complement...

  10. 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...

  11. Evaluation of complement proteins as screening markers for colorectal cancer

    DEFF Research Database (Denmark)

    Storm, Line; Christensen, Ib J; Jensenius, Jens C

    2015-01-01

    of the lectin pathway of the complement system were determined using time-resolved immunofluorometric assays. The first cohort investigated comprised a matched case-control study of 95 patients with CRC, 48 patients with adenomas and 48 individuals without neoplastic findings. Based on the results, Collectin......BACKGROUND: Colorectal cancer (CRC) is a leading cause of cancer death worldwide. Lack of symptoms results in late detection and increased mortality. Inflammation, including complement activation, plays an important role in tumorigenesis. EXPERIMENTAL DESIGN: The concentrations of nine proteins...

  12. Structural and functional characterization of human complement factor P

    DEFF Research Database (Denmark)

    Pedersen, Dennis

    The complement system is of great importance for the innate immune response, which can lead to opsonization and removal of invading pathogens, as well as immune complexes and damaged self-cells. Factor P (FP), also known as properdin, acts as a positive regulator of the alternative pathway...... of complement by stabilizing the C3 convertase complex (C3bBb). FP has also been suggested to serve as a pattern recognition molecule for the initiation of the alternative pathway. However, the molecular mechanisms of FP remain unclear due to its oligomeric nature and hence the atomic structure of FP has...

  13. Sheep serum complement sensitisation of sheep erythrocyte-rabbit antibody complexes for haemolysis by guinea-pig complement plus EDTA or Mg2+-EGTA.

    Science.gov (United States)

    Jonas, W; Stankiewicz, M

    1986-01-01

    Sheep erythrocyte (E)-rabbit antibody (A) complexes incubated with sheep serum diluted up to 1:5120 or 1:20480 and washed can be haemolysed by guinea-pig (g-p) serum (complement, C) containing EDTA or Mg2+-EGTA respectively as haemolytic finishing reagents. Sheep E carrying a high dose of rabbit A were necessary for this reaction, particularly with g-p C-EDTA. G-p serum (stored by freezing) was active as a haemolytic finishing reagent with both EDTA and Mg2+-EGTA. Reconstituted freeze-dried g-p serum (also stored by freezing) was haemolytically active with Mg2+-EGTA only. G-p serum preserved by Richardson's method did not function as a finishing reagent with EDTA or Mg2+-EGTA. A non-haemolytic prozone occurred with sheep E-rabbit A treated with dilutions of sheep serum or body fluid up to 1:160, particularly when g-p C (frozen)-EDTA was used as the finishing reagent. Sheep E-rabbit A were sensitized by serum, foetal lamb serum, pericardiac-, synovial- or ovarian follicle-fluids colostrum or milk for haemolysis by g-p C (frozen)-EDTA or -Mg2+-EGTA. With the C3 inhibitors cobra venom factor or salicylaldoxime, serum sensitisation of sheep E-rabbit A for haemolysis by g-p C (frozen)-EDTA or -Mg2+-EGTA was not blocked. Sensitisation by serum heated at 50 degrees C for 30 min (partial inactivation of C2) was incomplete. Inhibitors of C1 (antrypol, chelators of Ca2+ or heating serum at 56 degrees C for 30 min) partially or fully blocked sensitisation for haemolysis by both g-p C (frozen)-EDTA or -Mg2+-EGTA. These results show that at a minimum, components C1, C4 and C2 are present and functionally active in serum and some body fluids of sheep.

  14. 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 normal B cells are capable of activating the alternative pathway (AP) of complement in a CR2-dependent fashion. In this study we have investigated whether disturbances in this activity may be related to the altered phenotype of SLE B cells. Flow cytometry was used to measure expression of complement...... receptors and regulatory proteins on B cells from SLE patients, as well as the deposition of C3 fragments occurring in vivo or after in vitro AP activation. We have confirmed, for a proportion of the patients studied, reduced expression of CR1 and CR2 on B cells, and shown a consistency between low CR2...

  15. Complement profile and activation mechanisms by different LDL apheresis systems.

    Science.gov (United States)

    Hovland, Anders; Hardersen, Randolf; Nielsen, Erik Waage; Enebakk, Terje; Christiansen, Dorte; Ludviksen, Judith Krey; Mollnes, Tom Eirik; Lappegård, Knut Tore

    2012-07-01

    Extracorporeal removal of low-density lipoprotein (LDL) cholesterol by means of selective LDL apheresis is indicated in otherwise uncontrolled familial hypercholesterolemia. During blood-biomaterial interaction other constituents than the LDL particles are affected, including the complement system. We set up an ex vivo model in which human whole blood was passed through an LDL apheresis system with one of three different apheresis columns: whole blood adsorption, plasma adsorption and plasma filtration. The concentrations of complement activation products revealed distinctly different patterns of activation and adsorption by the different systems. Evaluated as the final common terminal complement complex (TCC) the whole blood system was inert, in contrast to the plasma systems, which generated substantial and equal amounts of TCC. Initial classical pathway activation was revealed equally for both plasma systems as increases in the C1rs-C1inh complex and C4d. Alternative pathway activation (Bb) was most pronounced for the plasma adsorption system. Although the anaphylatoxins (C3a and C5a) were equally generated by the two plasma separation systems, they were efficiently adsorbed to the plasma adsorption column before the "outlet", whereas they were left free in the plasma in the filtration system. Consequently, during blood-biomaterial interaction in LDL apheresis the complement system is modulated in different manners depending on the device composition. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. 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,

  17. Non-kinetic capabilities: complementing the kinetic prevalence to targeting

    NARCIS (Netherlands)

    Ducheine, P.A.L.; Ducheine, P.A.L.; Schmitt, M.N.; Osinga, F.P.B.

    2016-01-01

    Targeting is used in military doctrine to describe a military operational way, using (military) means to influence a target (or addressee) in order to achieve designated political and/or military goals. The four factors italicized are used to analyse non-kinetic targeting, thereby complementing our

  18. Non-kinetic capabilities: complementing the kinetic prevalence to targeting

    NARCIS (Netherlands)

    Ducheine, P.

    2014-01-01

    Targeting is used in military doctrine to describe a military operational way, using (military) means to influence a target (or addressee) in order to achieve designated political and/or military goals. The four factors italicized are used to analyse non-kinetic targeting, complementing our

  19. Interaction of toxic venoms with the complement system

    Science.gov (United States)

    Birdsey, Vanessa; Lindorfer, Jean; Gewurz, H.

    1971-01-01

    Thirty-nine venoms from various vertebrate and invertebrate species were tested for their ability to consume haemolytic complement (C) activity upon incubation in fresh guinea-pig serum. Nineteen had `anti-complementary' activity, and these were provisionally sorted into the following groups: Pattern I—exemplified by the Naja haje (Egyptian cobra) and six other Elapidae species (all cobras), which induced selective consumption of C3—C9, and led to formation of a stable C3—C9-consuming intermediate; Pattern II—exemplified by the Agkistrodon rhodostoma (Malayan pit viper), Bitis arietans (puff adder), Bothrops jararaca (South American pit viper), Bothrops atrox (Fer de Lance) and three other species, which induced marked consumption of C4 and C2, as well as C3—C9, but did not form a stable C3—C9-consuming intermediate; and individual animals, e.g. the Lachesis muta (bushmaster), which induced other patterns (III—VI) of complement component consumption. Active fractions of representative venoms were partially purified by ion exchange and gel filtration chromatography and their interactions with the complement system characterized further. It is anticipated that these enzymes, with a capacity to activate the complement system in unique ways, will prove to be of further experimental usefulness. PMID:4398349

  20. Complement factor d in age-related macular degeneration

    NARCIS (Netherlands)

    Stanton, C.M.; Yates, J.R.W.; Hollander, A.I. den; Seddon, J.M.; Swaroop, A.; Stambolian, D.; Fauser, S.; Hoyng, C.B.; Yu, Y.; Atsuhiro, K.; Branham, K.; Othman, M.; Chen, W.; Kortvely, E.; Chalmers, K.; Hayward, C.; Moore, A.T.; Dhillon, B.; Ueffing, M.; Wright, A.F.

    2011-01-01

    Purpose. To examine the role of complement factor D (CFD) in age-related macular degeneration (AMD) by analysis of genetic association, copy number variation, and plasma CFD concentrations. Methods. Single nucleotide polymorphisms (SNPs) in the CFD gene were genotyped and the results analyzed by

  1. Complement activation by salivary agglutinin is secretor status dependent

    NARCIS (Netherlands)

    Gunput, Sabrina T. G.; Ligtenberg, Antoon J. M.; Terlouw, Bas; Brouwer, Mieke; Veerman, Enno C. I.; Wouters, Diana

    2015-01-01

    Abstract 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

  2. Modification of the complement induced by PGE2 and gonadotropins.

    Science.gov (United States)

    Mangano, A; Nobile, G; Turnaturi, M C; Messina, L; Foti, L

    1990-11-01

    The Complement is one of the major effectors of the humoral aspecific immune system building up a defence mechanism of the organism. As it is known that some hormonal substances like gonadotropin (hCG) and some hormone-like substances (PGE2) influence the entire immunitary system, we wanted to see if they had specific action on the Complement. The measurement of CH50 was carried out using Mayer's method, derived by Ferrazzi and modified by us. Fractions C3 and C4 were measured by means of immunochemistry using Beckman nephelometer. The treatment with hCG (1,000 U + 10 Lf tetanus toxoid) caused an increase in the CH50 and in the fraction C3, while the fraction C4 was not modified. The treatment with PGE2 (0.25 microgram/rat/die) caused a higher increase of CH50 and C3 fraction. It seems possible to acknowledge C3 involvement in the variation of the Complement's haemolytic activity and this could confirm the intervention of the "alternative pathway". The notable increase in the activity of the Complement induced by hCG and PGE2 could indicate an alternative mechanism of activation of the aspecific humoral immunity in the defence of the organism in all those physio-pathological situations where these substances cause a state of depression of cellular mediated activity.

  3. 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,

  4. Activation of the lectin complement pathway on human renal ...

    African Journals Online (AJOL)

    This study aimed to investigate the roles of high glucose and mannose-binding lectin (MBL) on the activation of the lectin complement pathway (LCP) on human renal glomerular endothelial cells (HRGECs) in vitro. Flow cytometry analysis, immunofluorescence staining and Western blot were used to detect the cell surface ...

  5. The Effect of Different Chunking Strategies in Complementing Animated Instruction

    Science.gov (United States)

    Munyofu, Mine; Swain, William J.; Ausman, Bradley D.; Lin, Huifen; Kidwai, Khusro; Dwyer, Francis

    2007-01-01

    The purpose of this exploratory and small-scale study was to examine the instructional effects of different chunking strategies used to complement animated instruction in terms of facilitating achievement of higher order learning objectives. Eighty-five students were randomly assigned to three treatment groups: animated program instruction, simple…

  6. Erratum Pleurotus sajor-caju HSP100 complements a ...

    Indian Academy of Sciences (India)

    Madhu

    Pleurotus sajor-caju HSP100 complements a thermotolerance defect in hsp104 mutant Saccharomyces cerevisiae. Jin-Ohk Lee, Mi-Jeong Jeong, Tack-Ryun Kwon, Seung-Kon Lee, Myung-Ok Byun, Ill-Min Chung and. Soo-Chul Park 2006, J. Biosci., 31, 223–233. The following corrections require to be made in the printed ...

  7. X-linked inheritance of Fanconi anemia complementation group B.

    NARCIS (Netherlands)

    Meetei, AR; Levitus, M.; Xue, Y; Medhurst, A.L. dr.; Zwaan, M.; Ling, C; Rooimans, M.A.; Bier, P; Hoatlin, M.; Pals, G.; Winter, de J.P.; Joenje, H.

    2004-01-01

    Fanconi anemia is an autosomal recessive syndrome characterized by diverse clinical symptoms, hypersensitivity to DNA crosslinking agents, chromosomal instability and susceptibility to cancer. Fanconi anemia has at least 11 complementation groups (A, B, C, D1, D2, E, F, G, I, J, L); the genes

  8. Complementing System Dynamics with Object-Role Modelling

    NARCIS (Netherlands)

    Tulinayo, F.P.; Grössler, A.; Hoppenbrouwers, S.J.B.A.; Bommel, P. van

    2009-01-01

    In this paper we use Object-Role Modeling (ORM) to complement System Dynamics (SD). The art of SD modeling lies in discovering and representing feedback processes and other elements that determine the dynamics of the system. However, SD shows a lack of instruments for discovering and expressing

  9. Complementing System Dynamics with Object-role Modeling

    NARCIS (Netherlands)

    Tulinayo, F.P.; Grössler, A.; Hoppenbrouwers, S.J.B.A.; Bommel, P. van

    2009-01-01

    In this paper we use Object-Role Modeling (ORM) to complement System Dynamics (SD). The art of SD modeling lies in discovering and representing feedback processes and other elements that determine the dynamics of the system. However, SD shows a lack of instruments for discovering and expressing

  10. Construction of a bimolecular fluorescence complementation (BiFC ...

    African Journals Online (AJOL)

    Protein–protein interactions are essential for signal transduction in cells. Bimolecular fluorescence complementation (BiFC) is a novel technology that utilises green fluorescent proteins to visualize protein–protein interactions and subcellular protein localisation. BiFC based on pSATN vectors are a good system for ...

  11. Children's Understanding of the Addition/Subtraction Complement Principle

    Science.gov (United States)

    Torbeyns, Joke; Peters, Greet; De Smedt, Bert; Ghesquière, Pol; Verschaffel, Lieven

    2016-01-01

    Background: In the last decades, children's understanding of mathematical principles has become an important research topic. Different from the commutativity and inversion principles, only few studies have focused on children's understanding of the addition/subtraction complement principle (if a - b = c, then c + b = a), mainly relying on verbal…

  12. High protein complementation with high fiber substrates for oyster ...

    African Journals Online (AJOL)

    Agricultural residues have been world widely accepted for oyster mushroom culture. In this study, we used wheat straw, barley straw, maize stem residue, and lawn residue as substrates coupled with wheat bran, rice bran and soybean powder as complements for the growth of Pleurotus florida and Pleurotus ostreatus as ...

  13. A Graphical Teaching Tool for Understanding Two's Complement.

    Science.gov (United States)

    Luck, Carlos L.

    As part of the Electrical Engineering program at the Univesity of Southern Maine, students are typically introduced to Two's Complement algebra and representation, a method to include negative numbers in the binary representation of integers that is widely used in microprocessors and related digital systems. The traditional, procedural method to…

  14. Pleurotus sajor-caju HSP100 complements a thermotolerance ...

    Indian Academy of Sciences (India)

    To examine its function, PsHsp100 was transformed into a temperature-sensitive hsp104 deletion mutant Saccharomyces cerevisiae strain to test the hypothesis that PsHSP100 is an protein that functions in thermotolerance. Overexpression of PsHSP100 complemented the thermotolerance defect of the hsp104 mutant ...

  15. Recombinant production of the human complement factor 5a in ...

    African Journals Online (AJOL)

    Up to now, the human complement factor 5a (C5a) has only been produced in small quantities in Escherichia coli in a soluble, bioactive conformation, which is not suitable for commercial production systems. This stems from the extremely high instability of C5a, as well as its aggregation-prone nature. Therefore, we ...

  16. The complement system in the peripheral nerve: Friend or foe?

    NARCIS (Netherlands)

    Ramaglia, V.; Daha, M. R.; Baas, F.

    2008-01-01

    The complement (C) system plays a central role in innate immunity and bridges innate and adaptive immune responses. A fine balance of C activation and regulation mediates the elimination of invading pathogens and the protection of the host from excessive C deposition on healthy tissues. If this

  17. Expression of complement components in the peripheral nervous system

    NARCIS (Netherlands)

    de Jonge, Rosalein R.; van Schaik, Ivo N.; Vreijling, Jeroen P.; Troost, Dirk; Baas, Frank

    2004-01-01

    We have generated a SAGE (serial analysis of gene expression) library of normal sciatic nerve and found tags encoding for mRNAs of the complement system highly represented. RNA (RT-PCR and northern blot hybridization) and protein (western blot analysis and immunohistochemistry) studies confirmed

  18. Functional verbs in Gungbe: the case of inherent complement verbs

    Directory of Open Access Journals (Sweden)

    Enoch O. Aboh

    2015-06-01

    Full Text Available Traditional linguistics assumes that verbs are lexical categories that typically merge in the predicate domain of a sentence: VP. This study shows that, in Gungbe (Kwa, a significantly large class of items functioning as verbs heading a VP in a sentence may also serve as functional elements that merge within the functional skeleton of the clause. The discussion builds on the analysis of Inherent Complement Verbs (ICVs. In the Kwa literature, ICVs are defined as verbs which require a complement in their citation form (e.g., dó wèzùn lit. plant race; ‘to run’. This paper argues that these verbs can first merge in two syntactic positions: little v and V. When merged in v, such verbs select for a VP-complement involving an abstract empty V which necessarily takes a bare NP as complement (Hale & Keyser 1993. When merged in V, however, these verbs pattern like other Gungbe lexical verbs in selecting a DP argument. The paper concludes that Gungbe, (and possibly Kwa languages in general involve a class of verbal roots that can merge in the predicate head or in the functional domain. This finding supports Kayne’s (2009 recent antisymmetric approach to the lexicon.

  19. Defining the complement biomarker profile of C3 glomerulopathy

    DEFF Research Database (Denmark)

    Zhang, Yuzhou; Nester, Carla M; Martin, Bertha

    2014-01-01

    and C3GN) as well as higher levels of complement breakdown products including C3d (PC5 levels were significantly suppressed (P... breakdown product C5a was significantly higher only in patients with C3GN (PC5b-9 was elevated in both diseases but only the difference between...

  20. Vaccinia complement control protein: Multi-functional protein and a ...

    Indian Academy of Sciences (India)

    In addition to binding complement, VCP also binds to heparin. These two binding abilities can take place simultaneously and contribute to its many function and to its potential use in several inflammatory diseases, e.g. Alzheimer's disease (AD), CNS injury, xenotransplantation, etc. making it a truly fascinating molecule and ...

  1. Complementation of multiple sulfatase deficiency in somatic cell hybrids.

    Science.gov (United States)

    Fedde, K; Horwitz, A L

    1984-05-01

    Multiple sulfatase deficiency (MSD) is an inherited disorder characterized by deficient activity of seven different sulfatases. Genetic complementation for steroid sulfatase (STS), arylsulfatase A, and N-acetylgalactosamine 6-SO4 sulfatase was demonstrated in somatic cell hybrids between MSD fibroblasts and mouse cells ( LA9 ) or Chinese hamster cells ( CHW ). In an electrophoretic system that separates human and rodent STS isozymes, enzyme from hybrids migrated as human enzyme. We concluded that the rodent cell complemented the MSD deficiency and allowed normal expression of the STS structural gene. Some MSD- LA9 hybrids showed significant levels of human arylsulfatase A activity, as shown by the immunoprecipitation of active enzyme by human-specific antiserum. Complementation was also suggested for N-acetylgalactosamine 6- sulfatate sulfatase (GalNAc-6S sulfatase) in several MSD- LA9 hybrids by the demonstration of a significant increase in activity (10-fold) over that of the GalNAc-6S sulfatase-deficient parental mouse and MSD cells. Thus, it was possible to demonstrate complementation for more than one sulfatase in a single MSD-rodent hybrid. Normal levels of sulfatase activity in hybrids indicate that the sulfatase structural genes are intact in MSD cells.

  2. The role of complement in autoimmune renal disease

    NARCIS (Netherlands)

    Seelen, M. A.; Daha, M. R.

    The predominance of renal involvement in autoimmune diseases can most likely be assigned to the specialised function of the kidneys filtrating over 120 ml plasma per minute. Complement activation by autoantibodies directed against planted antigens or antigens already present in renal tissue in the

  3. Host Immune Evasion by Lyme and Relapsing Fever Borreliae: Findings to Lead Future Studies for Borrelia miyamotoi

    Science.gov (United States)

    Stone, Brandee L.; Brissette, Catherine A.

    2017-01-01

    The emerging pathogen, Borrelia miyamotoi, is a relapsing fever spirochete vectored by the same species of Ixodes ticks that carry the causative agents of Lyme disease in the US, Europe, and Asia. Symptoms caused by infection with B. miyamotoi are similar to a relapsing fever infection. However, B. miyamotoi has adapted to different vectors and reservoirs, which could result in unique physiology, including immune evasion mechanisms. Lyme Borrelia utilize a combination of Ixodes-produced inhibitors and native proteins [i.e., factor H-binding proteins (FHBPs)/complement regulator-acquiring surface proteins, p43, BBK32, BGA66, BGA71, CD59-like protein] to inhibit complement, while some relapsing fever spirochetes use C4b-binding protein and likely Ornithodoros-produced inhibitors. To evade the humoral response, Borrelia utilize antigenic variation of either outer surface proteins (Osps) and the Vmp-like sequences (Vls) system (Lyme borreliae) or variable membrane proteins (Vmps, relapsing fever borreliae). B. miyamotoi possesses putative FHBPs and antigenic variation of Vmps has been demonstrated. This review summarizes and compares the common mechanisms utilized by Lyme and relapsing fever spirochetes, as well as the current state of understanding immune evasion by B. miyamotoi. PMID:28154563

  4. Inhibition of zymosan-induced alternative complement pathway activation by concanavalin A.

    OpenAIRE

    Smith, M C; Pensky, J; Naff, G B

    1982-01-01

    Zymosan, a polysaccharide composed primarily of glucan and mannan residues, activates the complement system through the alternative complement pathway. We showed that zymosan-induced complement activation is inhibited by zymosan-bound lectins with carbohydrate specificities for mannosyl and glycosyl residues. Lectins unable to bind mannosyl or glucosyl residues did not inhibit zymosan-induced complement activation.

  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. DPP-4 inhibitors

    DEFF Research Database (Denmark)

    Deacon, Carolyn F.

    2016-01-01

    Dipeptidyl peptidase (DPP)-4 inhibitors inhibit the activity of the enzyme responsible for the initial rapid degradation of the incretin hormones, thereby enhancing their antihyperglycemic effects.......Dipeptidyl peptidase (DPP)-4 inhibitors inhibit the activity of the enzyme responsible for the initial rapid degradation of the incretin hormones, thereby enhancing their antihyperglycemic effects....

  7. Alginate microbeads are coagulation compatible, while alginate microcapsules activate coagulation secondary to complement or directly through FXII.

    Science.gov (United States)

    Gravastrand, Caroline; Hamad, Shamal; Fure, Hilde; Steinkjer, Bjørg; Ryan, Liv; Oberholzer, Josè; Lambris, John D; Lacík, Igor; Mollnes, Tom Eirik; Espevik, Terje; Brekke, Ole-Lars; Rokstad, Anne Mari

    2017-08-01

    Alginate microspheres are presently under evaluation for future cell-based therapy. Their ability to induce harmful host reactions needs to be identified for developing the most suitable devices and efficient prevention strategies. We used a lepirudin based human whole blood model to investigate the coagulation potentials of alginate-based microspheres: alginate microbeads (Ca/Ba Beads), alginate poly-l-lysine microcapsules (APA and AP microcapsules) and sodium alginate-sodium cellulose sulfate-poly(methylene-co-cyanoguanidine) microcapsules (PMCG microcapsules). Coagulation activation measured by prothrombin fragments 1+2 (PTF1.2) was rapidly and markedly induced by the PMCG microcapsules, delayed and lower induced by the APA and AP microcapsules, and not induced by the Ca/Ba Beads. Monocytes tissue factor (TF) expression was similarly activated by the microcapsules, whereas not by the Ca/Ba Beads. PMCG microcapsules-induced PTF1.2 was abolished by FXII inhibition (corn trypsin inhibitor), thus pointing to activation through the contact pathway. PTF1.2 induced by the AP and APA microcapsules was inhibited by anti-TF antibody, pointing to a TF driven coagulation. The TF induced coagulation was inhibited by the complement inhibitors compstatin (C3 inhibition) and eculizumab (C5 inhibition), revealing a complement-coagulation cross-talk. This is the first study on the coagulation potentials of alginate microspheres, and identifies differences in activation potential, pathways and possible intervention points. Alginate microcapsules are prospective candidate materials for cell encapsulation therapy. The material surface must be free of host cell adhesion to ensure free diffusion of nutrition and oxygen to the encapsulated cells. Coagulation activation is one gateway to cellular overgrowth through deposition of fibrin. Herein we used a physiologically relevant whole blood model to investigate the coagulation potential of alginate microcapsules and microbeads. The

  8. 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...

  9. Borrelia burgdorferi complement regulator-acquiring surface protein 2 does not contribute to complement resistance or host infectivity.

    Directory of Open Access Journals (Sweden)

    Adam S Coleman

    2008-08-01

    Full Text Available Borrelia burgdorferi, the pathogen of Lyme disease, cycles in nature through Ixodes ticks and mammalian hosts. At least five Complement Regulator-Acquiring Surface Proteins (BbCRASPs are produced by B. burgdorferi, which are thought to assist spirochetes in host immune evasion. Recent studies established that BbCRASP-2 is preferentially expressed in mammals, and elicits robust antibody response in infected hosts, including humans. We show that BbCRASP-2 is ubiquitously expressed in diverse murine tissues, but not in ticks, reinforcing a role of BbCRASP-2 in conferring B. burgdorferi defense against persistent host immune threats, such as complement. BbCRASP-2 immunization, however, fails to protect mice from B. burgdorferi infection and does not modify disease, as reflected by the development of arthritis. An infectious BbCRASP-2 mutant was generated, therefore, to examine the precise role of the gene product in spirochete infectivity. Similar to wild type B. burgdorferi, BbCRASP-2 mutants remain insensitive to complement-mediated killing in vitro, retain full murine infectivity and induce arthritis. Quantitative RT-PCR assessment indicates that survivability of BbCRASP-2-deficient B. burgdorferi is not due to altered expression of other BbCRASPs. Together, these results suggest that the function of a selectively expressed B. burgdorferi gene, BbCRASP-2, is not essential for complement resistance or infectivity in the murine host.

  10. Sialic acid on the neuronal glycocalyx prevents complement C1 binding and complement receptor-3-mediated removal by microglia.

    Science.gov (United States)

    Linnartz, Bettina; Kopatz, Jens; Tenner, Andrea J; Neumann, Harald

    2012-01-18

    Microglial cells are professional phagocytes of the CNS responsible for clearance of unwanted structures. Neuronal processes are marked by complement C1 before they are removed in development or during disease processes. Target molecules involved in C1 binding and mechanisms of clearance are still unclear. Here we show that the terminal sugar residue sialic acid of the mouse neuronal glycocalyx determines complement C1 binding and microglial-mediated clearance function. Several early components of the classical complement cascade including C1q, C1r, C1s, and C3 were produced by cultured mouse microglia. The opsonin C1q was binding to neurites after enzymatic removal of sialic acid residues from the neuronal glycocalyx. Desialylated neurites, but not neurites with intact sialic acid caps, were cleared and taken up by cocultured microglial cells. The removal of the desialylated neurites was mediated via the complement receptor-3 (CR3; CD11b/CD18). Data demonstrate that mouse microglial cells via CR3 recognize and remove neuronal structures with an altered neuronal glycocalyx lacking terminal sialic acid.

  11. Complement activation in Glioblastoma Multiforme pathophysiology: Evidence from serum levels and presence of complement activation products in tumor tissue

    NARCIS (Netherlands)

    T.A.M. Bouwens; L.A. Trouw (L.); R. Veerhuis; C.M.F. Dirven (Clemens); M.L.M. Lamfers (Martine); H. Al-Khawaja

    2015-01-01

    textabstractInflammation plays a key role in the pathophysiology of Glioblastoma Multiforme (GBM). Here we focus on the contribution of the so far largely ignored complement system.ELISA and immunohistochemistry were combined to assess levels and localization of critical components of the

  12. Pasteurella pneumotropica evades the human complement system by acquisition of the complement regulators factor H and C4BP.

    Directory of Open Access Journals (Sweden)

    Alfredo Sahagún-Ruiz

    Full Text Available Pasteurella pneumotropica is an opportunist Gram negative bacterium responsible for rodent pasteurellosis that affects upper respiratory, reproductive and digestive tracts of mammals. In animal care facilities the presence of P. pneumotropica causes severe to lethal infection in immunodeficient mice, being also a potential source for human contamination. Indeed, occupational exposure is one of the main causes of human infection by P. pneumotropica. The clinical presentation of the disease includes subcutaneous abscesses, respiratory tract colonization and systemic infections. Given the ability of P. pneumotropica to fully disseminate in the organism, it is quite relevant to study the role of the complement system to control the infection as well as the possible evasion mechanisms involved in bacterial survival. Here, we show for the first time that P. pneumotropica is able to survive the bactericidal activity of the human complement system. We observed that host regulatory complement C4BP and Factor H bind to the surface of P. pneumotropica, controlling the activation pathways regulating the formation and maintenance of C3-convertases. These results show that P. pneumotropica has evolved mechanisms to evade the human complement system that may increase the efficiency by which this pathogen is able to gain access to and colonize inner tissues where it may cause severe infections.

  13. 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...... malaria, possibly through induction of erythrophagocytosis and haemolysis. In contrast to other studies, this study did not find association between levels of the complement...

  14. Monotest in the complement fixation test: the Chorus system

    Directory of Open Access Journals (Sweden)

    Laura Meli

    2009-06-01

    Full Text Available The complement fixation test (CFT is a method used for the detection of antibodies against pathogens of infectious diseases, it has been proved to be a useful diagnostic method in the detection of acute disease in many medical laboratories.The test performed manually is time consuming and needs very skilled personnel.This study evaluates the automated Chorus CFT system with 87 serum samples in comparison with manual method using Virion-Serion reagents, against a panel of antigens, such as Adenovirus, Influenza A and B virus, Respiratory Syncythial Virus, Parainfluenza Mix, Mycoplasma Pneumoniae, and Echinococcus. The Chorus system includes standardized reagents and a monotest device to perform the single assay. In comparison to the manual CFT method, the correlation is 91.6% (7/83.The results obtained show that the automated Chorus system can be applied for detecting complement fixation antibodies against different infectious disease agents.

  15. Complements and the Wound Healing Cascade: An Updated Review

    Directory of Open Access Journals (Sweden)

    Hani Sinno

    2013-01-01

    Full Text Available Wound healing is a complex pathway of regulated reactions and cellular infiltrates. The mechanisms at play have been thoroughly studied but there is much still to learn. The health care system in the USA alone spends on average 9 billion dollars annually on treating of wounds. To help reduce patient morbidity and mortality related to abnormal or prolonged skin healing, an updated review and understanding of wound healing is essential. Recent works have helped shape the multistep process in wound healing and introduced various growth factors that can augment this process. The complement cascade has been shown to have a role in inflammation and has only recently been shown to augment wound healing. In this review, we have outlined the biology of wound healing and discussed the use of growth factors and the role of complements in this intricate pathway.

  16. Animal venoms/toxins and the complement system.

    Science.gov (United States)

    Tambourgi, Denise V; van den Berg, Carmen W

    2014-10-01

    Nature is a wealthy source of agents that have been shown to be beneficial to human health, but nature is also a rich source of potential dangerous health damaging compounds. This review will summarise and discuss the agents from the animal kingdom that have been shown to interact with the human complement (C) system. Most of these agents are toxins found in animal venoms and animal secretions. In addition to the mechanism of action of these toxins, their contribution to the field of complement, their role in human pathology and the potential benefit to the venomous animal itself will be discussed. Potential therapeutic applications will also be discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. A novel small molecule inhibitor of hepatitis C virus entry.

    Directory of Open Access Journals (Sweden)

    Carl J Baldick

    Full Text Available Small molecule inhibitors of hepatitis C virus (HCV are being developed to complement or replace treatments with pegylated interferons and ribavirin, which have poor response rates and significant side effects. Resistance to these inhibitors emerges rapidly in the clinic, suggesting that successful therapy will involve combination therapy with multiple inhibitors of different targets. The entry process of HCV into hepatocytes represents another series of potential targets for therapeutic intervention, involving viral structural proteins that have not been extensively explored due to experimental limitations. To discover HCV entry inhibitors, we utilized HCV pseudoparticles (HCVpp incorporating E1-E2 envelope proteins from a genotype 1b clinical isolate. Screening of a small molecule library identified a potent HCV-specific triazine inhibitor, EI-1. A series of HCVpp with E1-E2 sequences from various HCV isolates was used to show activity against all genotype 1a and 1b HCVpp tested, with median EC50 values of 0.134 and 0.027 µM, respectively. Time-of-addition experiments demonstrated a block in HCVpp entry, downstream of initial attachment to the cell surface, and prior to or concomitant with bafilomycin inhibition of endosomal acidification. EI-1 was equally active against cell-culture adapted HCV (HCVcc, blocking both cell-free entry and cell-to-cell transmission of virus. HCVcc with high-level resistance to EI-1 was selected by sequential passage in the presence of inhibitor, and resistance was shown to be conferred by changes to residue 719 in the carboxy-terminal transmembrane anchor region of E2, implicating this envelope protein in EI-1 susceptibility. Combinations of EI-1 with interferon, or inhibitors of NS3 or NS5A, resulted in additive to synergistic activity. These results suggest that inhibitors of HCV entry could be added to replication inhibitors and interferons already in development.

  18. Word order variation and foregrounding of complement clauses

    DEFF Research Database (Denmark)

    Christensen, Tanya Karoli; Jensen, Torben Juel

    2015-01-01

    Through mixed models analyses of complement clauses in a corpus of spoken Danish we examine the role of sentence adverbials in relation to a word order distinction in Scandinavian signalled by the relative position of sentence adverbials and finite verb (V>Adv vs. Adv>V). The type of sentence adv...... foregrounded information, and exploit the random intercepts assigned to the individual adverbials for further exploring the functions of sentence adverbials that behave unexpectedly based on the predictions of the model....

  19. Pleurotus sajor-caju HSP100 complements a thermotolerance ...

    Indian Academy of Sciences (India)

    Madhu

    functional as an HSP100 in yeast and could play an important role in thermotolerance in P. sajor-caju. [Lee J-O, Jeong M-J, Kwon T-R, Lee S-K, Byun M-O, Chung I-M and Park S-C 2006 Pleurotus sajor-caju HSP100 complements a thermotolerance defect in hsp104 mutant Saccharomyces cerevisiae; J. Biosci. 31 223–233].

  20. Complement pathway biomarkers and age-related macular degeneration

    Science.gov (United States)

    Gemenetzi, M; Lotery, A J

    2016-01-01

    In the age-related macular degeneration (AMD) ‘inflammation model', local inflammation plus complement activation contributes to the pathogenesis and progression of the disease. Multiple genetic associations have now been established correlating the risk of development or progression of AMD. Stratifying patients by their AMD genetic profile may facilitate future AMD therapeutic trials resulting in meaningful clinical trial end points with smaller sample sizes and study duration. PMID:26493033

  1. Complement-dependent transport of antigen into B cell follicles

    DEFF Research Database (Denmark)

    Gonzalez, Santiago F.; Lukacs-Kornek, Veronika; Kuligowski, Michael P.

    2010-01-01

    an additional novel pathway in which complement C3 and its receptors enhance humoral immunity through delivery of Ag to the B cell compartment. In this review, we discuss this pathway and highlight several novel exceptions recently found with a model influenza vaccine, such as mannose-binding lectin...... opsonization of influenza and uptake by macrophages, and the capture of virus by dendritic cells residing in the medullary compartment of peripheral lymph nodes....

  2. Complementation of multiple sulfatase deficiency in somatic cell hybrids.

    OpenAIRE

    Fedde, K; Horwitz, A L

    1984-01-01

    Multiple sulfatase deficiency (MSD) is an inherited disorder characterized by deficient activity of seven different sulfatases. Genetic complementation for steroid sulfatase (STS), arylsulfatase A, and N-acetylgalactosamine 6-SO4 sulfatase was demonstrated in somatic cell hybrids between MSD fibroblasts and mouse cells ( LA9 ) or Chinese hamster cells ( CHW ). In an electrophoretic system that separates human and rodent STS isozymes, enzyme from hybrids migrated as human enzyme. We concluded ...

  3. Emerging and novel functions of complement protein C1q

    Directory of Open Access Journals (Sweden)

    Lubna eKouser

    2015-06-01

    Full Text Available Complement protein C1q, the recognition subcomponent of the classical pathway, performs a diverse range of complement and non-complement functions. It can bind various ligands derived from self, non-self and altered-self and modulate the functions of immune and non-immune cells including dendritic cells and microglia. C1q involvement in the clearance of apoptotic cells and subsequent B cell tolerance is more established now. Recent evidence appears to suggest that C1q plays an important role in pregnancy where its deficiency and dysregulation can have adverse effects, leading to preeclampsia, missed abortion, miscarriage or spontaneous loss and various infections. C1q is also produced locally in the Central Nervous System, and has a protective role against pathogens and possible inflammatory functions while interacting with aggregated proteins leading to neurodegenerative diseases. C1q role in synaptic pruning, and thus CNS development, anti-cancer effects as an immune surveillance molecule, and possibly in ageing are areas of extensive research.

  4. Xeroderma pigmentosum complementation group G associated with Cockayne syndrome.

    Science.gov (United States)

    Vermeulen, W; Jaeken, J; Jaspers, N G; Bootsma, D; Hoeijmakers, J H

    1993-07-01

    Xeroderma pigmentosum (XP) and Cockayne syndrome (CS) are two rare inherited disorders with a clinical and cellular hypersensitivity to the UV component of the sunlight spectrum. Although the two traits are generally considered as clinically and genetically distinct entities, on the biochemical level a defect in the nucleotide excision-repair (NER) pathway is involved in both. Classical CS patients are primarily deficient in the preferential repair of DNA damage in actively transcribed genes, whereas in most XP patients the genetic defect affects both "preferential" and "overall" NER modalities. Here we report a genetic study of two unrelated, severely affected patients with the clinical characteristics of CS but with a biochemical defect typical of XP. By complementation analysis, using somatic cell fusion and nuclear microinjection of cloned repair genes, we assign these two patients to XP complementation group G, which previously was not associated with CS. This observation extends the earlier identification of two patients with a rare combined XP/CS phenotype within XP complementation groups B and D, respectively. It indicates that some mutations in at least three of the seven genes known to be involved in XP also can result in a picture of partial or even full-blown CS. We conclude that the syndromes XP and CS are biochemically closely related and may be part of a broader clinical disease spectrum. We suggest, as a possible molecular mechanism underlying this relation, that the XPGC repair gene has an additional vital function, as shown for some other NER genes.

  5. 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.

  6. The role of the complement system in diabetic nephropathy.

    Science.gov (United States)

    Flyvbjerg, Allan

    2017-05-01

    The development of type 1 and type 2 diabetes mellitus has a substantial negative impact on morbidity and mortality and is responsible for substantial individual and socioeconomic costs worldwide. One of the most serious consequences of diabetes mellitus is the development of diabetic angiopathy, which manifests clinically as microvascular and macrovascular complications. One microvascular complication, diabetic nephropathy, is the most common cause of end-stage renal disease in developed countries. Although several available therapeutic interventions can delay the onset and progression of diabetic nephropathy, morbidity associated with this disease remains high and new therapeutic approaches are needed. In addition, not all patients with diabetes mellitus will develop diabetic nephropathy and thus new biomarkers are needed to identify individuals who will develop this life-threatening disease. An increasing body of evidence points toward a role of the complement system in the pathogenesis of diabetic nephropathy. For example, circulating levels of mannose-binding lectin (MBL), a pattern recognition molecule of the innate immune system, have emerged as a robust biomarker for the development and progression of this disease, and evidence suggests that MBL, H-ficolin, complement component C3 and the membrane attack complex might contribute to renal injury in the hyperglycaemic mileu. New approaches to modulate the complement system might lead to the development of new agents to prevent or slow the progression of diabetic nephropathy.

  7. [Changes in the complement system in membranoproliferative glomerulonephritis].

    Science.gov (United States)

    Yurova, V A; Bobrova, L A; Kozlovskaya, N L; Korotchaeva, Yu V; Serova, A G; Kozlov, L V; Andina, S S; Demyanova, K A; Kuchieva, A M; Roshchupkina, S V

    To compare the clinical manifestations membranoproliferative glomerulonephritis (MPGN) in its idiopathic variant, lupus nephritis (LN), and C3 glomerulopathy (C3-GP), by comparing them with changes in the complement system. The clinic of nephrology followed up 42 patients with different types of MPGN in 2013 to 2015. The study included 35 patients divided into 3 groups: 1) 8 patients with C3-GP, 2) 13 with idiopathic MPGN; 3) 14 with Class IV LN. The investigators studied the blood and urine levels of components and markers for activation of the classical and alternative pathways (C3 and C4, С3а, C5a, CFH, CFB, and CFD) of the terminal complement complex (TCC). The detection rate of C3-GP was 19%. The patients with C3-GP were noted to have the lowest blood concentration of S3 and the highest urinary level of С3а, C5a, TCC, CFH, CFB, and CFD. C3 nephritic factor was detected in 2 patients from the C3-GP (dense deposit disease) group. Alternative complement pathway dysregulation caused by genetic or autoimmune factors plays a leading role in the pathogenesis of C3-GP.

  8. Early intra-articular complement activation in ankle fractures.

    Science.gov (United States)

    Schmal, Hagen; Salzmann, Gian M; Niemeyer, Philipp; Langenmair, Elia; Guo, Renfeng; Schneider, Conny; Habel, Maria; Riedemann, Niels

    2014-01-01

    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-1 β, 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-1 β 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.

  9. IL-17A deficiency mitigates bleomycin-induced complement activation during lung fibrosis.

    Science.gov (United States)

    Cipolla, Ellyse; Fisher, Amanda J; Gu, Hongmei; Mickler, Elizabeth A; Agarwal, Manisha; Wilke, Carol A; Kim, Kevin K; Moore, Bethany B; Vittal, Ragini

    2017-12-01

    Interleukin 17A (IL-17A) and complement (C') activation have each been implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF). We have reported that IL-17A induces epithelial injury via TGF-β in murine bronchiolitis obliterans; that TGF-β and the C' cascade present signaling interactions in mediating epithelial injury; and that the blockade of C' receptors mitigates lung fibrosis. In the present study, we investigated the role of IL-17A in regulating C' in lung fibrosis. Microarray analyses of mRNA isolated from primary normal human small airway epithelial cells indicated that IL-17A (100 ng/ml; 24 h; n = 5 donor lungs) induces C' components (C' factor B, C3 , and GPCR kinase isoform 5), cytokines ( IL8 , -6 , and -1B ), and cytokine ligands ( CXCL1 , -2 , -3 , -5 , -6 , and -16 ). IL-17A induces protein and mRNA regulation of C' components and the synthesis of active C' 3a (C3a) in normal primary human alveolar type II epithelial cells (AECs). Wild-type mice subjected to IL-17A neutralization and IL-17A knockout ( il17a -/- ) mice were protected against bleomycin (BLEO)-induced fibrosis and collagen deposition. Further, BLEO-injured il17a -/- mice had diminished levels of circulating Krebs Von Den Lungen 6 (alveolar epithelial injury marker), local caspase-3/7, and local endoplasmic reticular stress-related genes. BLEO-induced local C' activation [C3a, C5a, and terminal C' complex (C5b-9)] was attenuated in il17a -/- mice, and IL-17A neutralization prevented the loss of epithelial C' inhibitors (C' receptor-1 related isoform Y and decay accelerating factor), and an increase in local TUNEL levels. RNAi-mediated gene silencing of il17a in fibrotic mice arrested the progression of lung fibrosis, attenuated cellular apoptosis (caspase-3/7) and lung deposition of collagen and C' (C5b-9). Compared to normals, plasma from IPF patients showed significantly higher hemolytic activity. Our findings demonstrate that limiting complement activation by

  10. The lectin complement pathway serine proteases (MASPs) represent a possible crossroad between the coagulation and complement systems in thromboinflammation

    DEFF Research Database (Denmark)

    Kozarcanin, H; Lood, C; Fog, Lea Munthe

    2016-01-01

    both in vitro and in vivo. These findings may represent a crossroad between the complement and the coagulation systems. SUMMARY: BACKGROUND: The activated forms of the complement lectin pathway (LP) proteases MASP-1 and MASP-2 are able to cleave the coagulation factors prothrombin, fibrinogen, factor...... by AT during clotting without the assistance of heparin. In all other cases the MASPs were, as previously reported, inactivated by C1-INH. In systemic lupus erythematosus patients with thrombotic disease and in polytrauma patients, the levels of activated MASP-1 and MASP-2 in complex with both AT and C1-INH...... were associated with markers of thrombotic disease and contact/coagulation system activation. CONCLUSIONS: MASP-1 and MASP-2 are activated during blood clotting. This activation is triggered by activated platelets and by the generation of fibrin during thrombotic reactions in vitro and in vivo, and may...

  11. [Pathogenesis of systemic lupus erythematosus (SLE)--the central role of complement].

    Science.gov (United States)

    Trendelenburg, M

    2005-05-01

    The traditional view of the pathogenesis of SLE is that immune complexes containing autoantigens and autoantibodies activate complement, and that this causes inflammatory injury to tissues. Although this model is biologically plausible, it cannot account for all of the clinical observations that link the complement system and SLE. In particular, the observation that complement deficiency causes lupus is hard to reconcile with the concept that complement activation products are the major cause of inflammatory injury in the disease. More recent data suggests that the role of complement in SLE is rather protective. Bindung of complement might prevent an autoimmune response by supporting the clearance of immuncomplexes and apoptotic cell debrid.

  12. Trypanosoma cruzi Evades the Complement System as an Efficient Strategy to Survive in the Mammalian Host: The Specific Roles of Host/Parasite Molecules and Trypanosoma cruzi Calreticulin

    Science.gov (United States)

    Ramírez-Toloza, Galia; Ferreira, Arturo

    2017-01-01

    American Trypanosomiasis is an important neglected reemerging tropical parasitism, infecting about 8 million people worldwide. Its agent, Trypanosoma cruzi, exhibits multiple mechanisms to evade the host immune response and infect host cells. An important immune evasion strategy of T. cruzi infective stages is its capacity to inhibit the complement system activation on the parasite surface, avoiding opsonizing, immune stimulating and lytic effects. Epimastigotes, the non-infective form of the parasite, present in triatomine arthropod vectors, are highly susceptible to complement-mediated lysis while trypomastigotes, the infective form, present in host bloodstream, are resistant. Thus T. cruzi susceptibility to complement varies depending on the parasite stage (amastigote, trypomastigotes or epimastigote) and on the T. cruzi strain. To avoid complement-mediated lysis, T. cruzi trypomastigotes express on the parasite surface a variety of complement regulatory proteins, such as glycoprotein 58/68 (gp58/68), T. cruzi complement regulatory protein (TcCRP), trypomastigote decay-accelerating factor (T-DAF), C2 receptor inhibitor trispanning (CRIT) and T. cruzi calreticulin (TcCRT). Alternatively, or concomitantly, the parasite captures components with complement regulatory activity from the host bloodstream, such as factor H (FH) and plasma membrane-derived vesicles (PMVs). All these proteins inhibit different steps of the classical (CP), alternative (AP) or lectin pathways (LP). Thus, TcCRP inhibits the CP C3 convertase assembling, gp58/68 inhibits the AP C3 convertase, T-DAF interferes with the CP and AP convertases assembling, TcCRT inhibits the CP and LP, CRIT confers ability to resist the CP and LP, FH is used by trypomastigotes to inhibit the AP convertases and PMVs inhibit the CP and LP C3 convertases. Many of these proteins have similar molecular inhibitory mechanisms. Our laboratory has contributed to elucidate the role of TcCRT in the host-parasite interplay

  13. Trypanosoma cruzi Evades the Complement System as an Efficient Strategy to Survive in the Mammalian Host: The Specific Roles of Host/Parasite Molecules and Trypanosoma cruzi Calreticulin

    Directory of Open Access Journals (Sweden)

    Galia Ramírez-Toloza

    2017-09-01

    Full Text Available American Trypanosomiasis is an important neglected reemerging tropical parasitism, infecting about 8 million people worldwide. Its agent, Trypanosoma cruzi, exhibits multiple mechanisms to evade the host immune response and infect host cells. An important immune evasion strategy of T. cruzi infective stages is its capacity to inhibit the complement system activation on the parasite surface, avoiding opsonizing, immune stimulating and lytic effects. Epimastigotes, the non-infective form of the parasite, present in triatomine arthropod vectors, are highly susceptible to complement-mediated lysis while trypomastigotes, the infective form, present in host bloodstream, are resistant. Thus T. cruzi susceptibility to complement varies depending on the parasite stage (amastigote, trypomastigotes or epimastigote and on the T. cruzi strain. To avoid complement-mediated lysis, T. cruzi trypomastigotes express on the parasite surface a variety of complement regulatory proteins, such as glycoprotein 58/68 (gp58/68, T. cruzi complement regulatory protein (TcCRP, trypomastigote decay-accelerating factor (T-DAF, C2 receptor inhibitor trispanning (CRIT and T. cruzi calreticulin (TcCRT. Alternatively, or concomitantly, the parasite captures components with complement regulatory activity from the host bloodstream, such as factor H (FH and plasma membrane-derived vesicles (PMVs. All these proteins inhibit different steps of the classical (CP, alternative (AP or lectin pathways (LP. Thus, TcCRP inhibits the CP C3 convertase assembling, gp58/68 inhibits the AP C3 convertase, T-DAF interferes with the CP and AP convertases assembling, TcCRT inhibits the CP and LP, CRIT confers ability to resist the CP and LP, FH is used by trypomastigotes to inhibit the AP convertases and PMVs inhibit the CP and LP C3 convertases. Many of these proteins have similar molecular inhibitory mechanisms. Our laboratory has contributed to elucidate the role of TcCRT in the host

  14. P-I snake venom metalloproteinase is able to activate the complement system by direct cleavage of central components of the cascade.

    Directory of Open Access Journals (Sweden)

    Giselle Pidde-Queiroz

    Full Text Available BACKGROUND: Snake Venom Metalloproteinases (SVMPs are amongst the key enzymes that contribute to the high toxicity of snake venom. We have recently shown that snake venoms from the Bothrops genus activate the Complement system (C by promoting direct cleavage of C-components and generating anaphylatoxins, thereby contributing to the pathology and spread of the venom. The aim of the present study was to isolate and characterize the C-activating protease from Bothrops pirajai venom. RESULTS: Using two gel-filtration chromatography steps, a metalloproteinase of 23 kDa that activates Complement was isolated from Bothrops pirajai venom. The mass spectrometric identification of this protein, named here as C-SVMP, revealed peptides that matched sequences from the P-I class of SVMPs. C-SVMP activated the alternative, classical and lectin C-pathways by cleaving the α-chain of C3, C4 and C5, thereby generating anaphylatoxins C3a, C4a and C5a. In vivo, C-SVMP induced consumption of murine complement components, most likely by activation of the pathways and/or by direct cleavage of C3, leading to a reduction of serum lytic activity. CONCLUSION: We show here that a P-I metalloproteinase from Bothrops pirajai snake venom activated the Complement system by direct cleavage of the central C-components, i.e., C3, C4 and C5, thereby generating biologically active fragments, such as anaphylatoxins, and by cleaving the C1-Inhibitor, which may affect Complement activation control. These results suggest that direct complement activation by SVMPs may play a role in the progression of symptoms that follow envenomation.

  15. Effects of Bothrops atrox venom and two isolated toxins on the human complement system: Modulation of pathways and generation of anaphylatoxins.

    Science.gov (United States)

    Menaldo, Danilo L; Bernardes, Carolina P; Jacob-Ferreira, Anna L; Nogueira-Santos, Cíntia G; Casare-Ogasawara, Tania M; Pereira-Crott, Luciana S; Sampaio, Suely V

    2016-12-01

    The complement system plays important biological roles, including the activation of inflammatory processes in response to the generation of proteolytic fragments of its components. Here we evaluated the effects of Bothrops atrox venom and two of its toxins (the P-I metalloprotease Batroxase and the acidic phospholipase A 2 BatroxPLA 2 ) on the human complement system, evaluating their effects on the classical (CP), lectin (LP) and alternative (AP) pathways, as well as on different complement components associated to the generation of anaphylatoxins. Primarily, the venom and both toxins modulated the hemolytic activity of the complement CP, with the venom and Batroxase reducing this activity and BatroxPLA 2 increasing it. ELISA deposition assays indicated that B. atrox venom and Batroxase were also capable of modulating all three activation pathways (CP, LP and AP), reducing their activity after incubation with normal human serum (NHS), while BatroxPLA 2 apparently only interfered with AP. Additionally, the venom and Batroxase, but not BatroxPLA 2 , promoted significant degradation of the components C3, C4, Factor B and C1-Inhibitor, as shown by Western blot and SDS-PAGE analyses, also generating anaphylatoxins C3a, C4a and C5a. Therefore, B. atrox venom and Batroxase were able to activate the complement system by direct proteolytic action on several components, generating anaphylatoxins and affecting the activation pathways, while BatroxPLA 2 only interfered with the hemolysis induced by CP and the C3 deposition related to AP. Our results indicate that Batroxase and possibly other metalloproteases should be the main toxins in B. atrox venom to induce pronounced effects on the complement system. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Xeroderma pigmentosum complementation group G associated with Cockayne syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Vermeulen, W.; Jaspers, N.G.J.; Bootsma, D.; Hoeijmakers, J.H.J. (Erasmus Univ., Rotterdam (Belgium)); Jaeken, J. (Univ. Hospital Gasthuisberg, Leuven (Belgium))

    1993-07-01

    Xeroderma pigmentosum (XP) and Cockayne syndrome (CS) are two rare inherited disorders with a clinical and cellular hypersensitivity to the UV component of the sunlight spectrum. Although the two traits are generally considered as clinically and genetically distinct entities, on the biochemical level a defect in the nucleotide excision-repair (NER) pathway is involved in both. Classical CS patients are primarily deficient in the preferential repair of DNA damage in actively transcribed genes, whereas in most XP patients the genetic defect affects both [open quotes]preferential[close quotes] and [open quotes]overall[close quotes] NER modalities. Here the authors report a genetic study of two unrelated, severely affected patients with the clinical characteristics of CS but with a biochemical defect typical of XP. By complementation analysis, using somatic cell fusion and nuclear microinjection of cloned repair genes, they assign these two patients to XP complementation group G, which previously was not associated with CS. This observation extends the earlier identification of two patients with a rare combined XP/CS phenotype within XP complementation groups B and D, respectively. It indicates that some mutations in at least three of the seven genes known to be involved in XP also can result in a picture of partial or even full-blown CS. It is concluded that the syndromes XP and CS are biochemically closely related and may be part of a broader clinical disease spectrum. The authors suggest, as a possible molecular mechanism underlying this relation, that the XPGC repair gene has an additional vital function, as shown for some other NER genes. 33 refs., 5 tabs.

  17. Vasculitides and the Complement System: a Comprehensive Review.

    Science.gov (United States)

    Chimenti, Maria Sole; Ballanti, Eleonora; Triggianese, Paola; Perricone, Roberto

    2015-12-01

    Systemic vasculitides are a group of rare diseases characterized by inflammation of the arterial or venous vessel wall, causing stenosis or thrombosis. Clinical symptoms may be limited to skin or to other organs or may include multiple manifestations as systemic conditions. The pathogenesis is related to the presence of leukocytes in the vessels and to the IC deposition, which implies the activation of the complement system (CS) and then the swelling and damage of vessel mural structures. The complement system (CS) is involved in the pathogenesis of several autoimmune diseases, including systemic vasculitides. This enzymatic system is a part of the innate immune system, and its function is linked to the modulation of the adaptive immunity and in bridging innate and adaptive responses. Its activation is also critical for the development of natural antibodies and T cell response and for the regulation of autoreactive B cells. Complement triggering contributes to inflammation-driven tissue injury, which occurs during the ischemia/reperfusion processes, vasculitides, nephritis, arthritis, and many others diseases. In systemic vasculitides, a group of uncommon diseases characterized by blood vessel inflammation, the contribution of CS in the development of inflammatory damage has been demonstrated. Treatment is mainly based on clinical manifestations and severity of organ involvement. Evidences on the efficacy of traditional immunosuppressive therapies have been collected as well as data from clinical trials that involve the modulation of the CS. In particular in small-medium-vessel vasculitides, the CS represents an attractive target. Herein, we reviewed the pathogenetic role of CS in these systemic vasculitides as urticarial vasculitis, ANCA-associated vasculitides, anti-glomerular basement membrane disease, cryoglobulinaemic vasculitides, Henoch-Schönlein purpura/IgA nephropathy, and Kawasaki disease and therefore its potential therapeutic use in this context.

  18. Role of complement in in vitro and in vivo lung inflammatory reactions

    DEFF Research Database (Denmark)

    Czermak, B J; Lentsch, A B; Bless, N M

    1998-01-01

    Complement is one of the integral buttresses of the inflammatory response. In addition to host defense activities, proinflammatory properties of several complement components are described. This overview elucidates the role of complement in inflammatory reactions in vitro and in vivo, focusing...... on the complement activation products, C5a, and the membrane attack complex, C5b-9. Using several approaches, the impact of these complement components in mechanisms relevant to neutrophil recruitment is emphasized. In addition, the participation of complement in endothelial superoxide generation and its essential...... requirement for full expression of lung injury is demonstrated, as are the involved intracellular signal transduction pathways. Understanding the mechanisms of complement-induced proinflammatory effects may provide a basis for future therapeutic blockade of complement and/or its activation products....

  19. Electroencephalography Is a Good Complement to Currently Established Dementia Biomarkers

    DEFF Research Database (Denmark)

    Ferreira, Daniel; Jelic, Vesna; Cavallin, Lena

    2016-01-01

    BACKGROUND/AIMS: Dementia biomarkers that are accessible and easily applicable in nonspecialized clinical settings are urgently needed. Quantitative electroencephalography (qEEG) is a good candidate, and the statistical pattern recognition (SPR) method has recently provided promising results. We......EEG to the diagnostic workup substantially increases the detection of AD pathology even in pre-dementia stages and improves differential diagnosis. EEG could serve as a good complement to currently established dementia biomarkers since it is cheap, noninvasive, and extensively applied outside academic centers....

  20. 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.

  1. Susceptibility to advanced age-related macular degeneration and alleles of complement factor H, complement factor B, complement component 2, complement component 3, and age-related maculopathy susceptibility 2 genes in a Mexican population

    Science.gov (United States)

    Buentello-Volante, Beatriz; Rodriguez-Ruiz, Gabriela; Miranda-Duarte, Antonio; Pompa-Mera, Ericka N.; Graue-Wiechers, Federico; Bekker-Méndez, Carolina; Ayala-Ramirez, Raul; Quezada, Carlos; Rodríguez-Loaiza, Jose L.

    2012-01-01

    Purpose To investigate the association of age-related macular degeneration (AMD)–high risk alleles of the complement factor H (CFH), complement factor B (CFB), complement component 2 (C2), complement component 3 (C3), and age-related maculopathy susceptibility 2 (ARMS2) genes in a Mexican population for the first time. Methods Genotyping was performed for the Y402H variant of CFH, for the L9H, R32Q, and K565E variants of CFB, the E318D variant of C2, the A69S variant of ARMS2, and the R102G variant of C3 in 159 Mexican mestizo patients at advanced stages of AMD, i.e., CARMS (Clinical Age-Related Maculopathy Staging System) grade 4 or 5. The frequency of these variants was also investigated in a group of 152 control subjects without AMD. Genomic DNA was extracted from blood leukocytes, and genotyping was performed using PCR followed by direct sequencing. Allele-specific restriction enzyme digestion was used to detect the R102G polymorphism in C3. Results There were significant differences in the allelic distribution between the two groups for CFH Y402H (p=1×10−5), ARMS A69S (p=4×10−7), and CFB R32Q (p=0.01). The odds ratios (95% confidence interval) obtained for the risk alleles of these three variants were 3.8 (2.4–5.9), 3.04 (2.2–4.3), and 2.5 (1.1–5.7), respectively. Haplotype analysis including the two most significantly associated alleles (CFH Y402H and ARMS A69S) indicated that the C-T combination conferred an odds ratio (95% confidence interval) of 6.9 (3.2–14.8). The exposed attributable risk for this particular haplotype was 85.5%. Conclusions This is the first case-control investigation of AMD–high risk alleles in a Latino population. Our results support that CFH, ARMS2, and CFB AMD-risk alleles are consistently associated with the disease, even in ethnic groups with a complex admixture of ancestral populations such as Mexican mestizos. PMID:23112567

  2. Approximate Schur complement preconditioning of the lowest order nodal discretizations

    Energy Technology Data Exchange (ETDEWEB)

    Moulton, J.D.; Ascher, U.M. [Univ. of British Columbia, Vancouver, British Columbia (Canada); Morel, J.E. [Los Alamos National Lab., NM (United States)

    1996-12-31

    Particular classes of nodal methods and mixed hybrid finite element methods lead to equivalent, robust and accurate discretizations of 2nd order elliptic PDEs. However, widespread popularity of these discretizations has been hindered by the awkward linear systems which result. The present work exploits this awkwardness, which provides a natural partitioning of the linear system, by defining two optimal preconditioners based on approximate Schur complements. Central to the optimal performance of these preconditioners is their sparsity structure which is compatible with Dendy`s black box multigrid code.

  3. Susceptibility to advanced age-related macular degeneration and alleles of complement factor H, complement factor B, complement component 2, complement component 3, and age-related maculopathy susceptibility 2 genes in a Mexican population.

    Science.gov (United States)

    Buentello-Volante, Beatriz; Rodriguez-Ruiz, Gabriela; Miranda-Duarte, Antonio; Pompa-Mera, Ericka N; Graue-Wiechers, Federico; Bekker-Méndez, Carolina; Ayala-Ramirez, Raul; Quezada, Carlos; Rodríguez-Loaiza, Jose L; Zenteno, Juan C

    2012-01-01

    To investigate the association of age-related macular degeneration (AMD)-high risk alleles of the complement factor H (CFH), complement factor B (CFB), complement component 2 (C2), complement component 3 (C3), and age-related maculopathy susceptibility 2 (ARMS2) genes in a Mexican population for the first time. Genotyping was performed for the Y402H variant of CFH, for the L9H, R32Q, and K565E variants of CFB, the E318D variant of C2, the A69S variant of ARMS2, and the R102G variant of C3 in 159 Mexican mestizo patients at advanced stages of AMD, i.e., CARMS (Clinical Age-Related Maculopathy Staging System) grade 4 or 5. The frequency of these variants was also investigated in a group of 152 control subjects without AMD. Genomic DNA was extracted from blood leukocytes, and genotyping was performed using PCR followed by direct sequencing. Allele-specific restriction enzyme digestion was used to detect the R102G polymorphism in C3. There were significant differences in the allelic distribution between the two groups for CFH Y402H (p=1×10(-5)), ARMS A69S (p=4×10(-7)), and CFB R32Q (p=0.01). The odds ratios (95% confidence interval) obtained for the risk alleles of these three variants were 3.8 (2.4-5.9), 3.04 (2.2-4.3), and 2.5 (1.1-5.7), respectively. Haplotype analysis including the two most significantly associated alleles (CFH Y402H and ARMS A69S) indicated that the C-T combination conferred an odds ratio (95% confidence interval) of 6.9 (3.2-14.8). The exposed attributable risk for this particular haplotype was 85.5%. This is the first case-control investigation of AMD-high risk alleles in a Latino population. Our results support that CFH, ARMS2, and CFB AMD-risk alleles are consistently associated with the disease, even in ethnic groups with a complex admixture of ancestral populations such as Mexican mestizos.

  4. 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...

  5. Entailments, pragmatic assertion and mood in Spanish complements

    OpenAIRE

    Mejías-Bikandi, Errapel

    2016-01-01

    This paper examines a frequently overlooked class of expressions in Spanish that license the subjunctive mood in a complement clause. This class contains expressions such as poco/a/s “few”, menos de “less than” and solo “only”. The goal of the paper is to offer an account of the use of mood with these expressions that incorporates the data under discussion into previous pragmatic accounts of mood based on notions of assertion and informative value. The paper first offers a semantic characteri...

  6. CYP4F18-Deficient Neutrophils Exhibit Increased Chemotaxis to Complement Component C5a

    Directory of Open Access Journals (Sweden)

    Rachel Vaivoda

    2015-01-01

    Full Text Available CYP4Fs were first identified as enzymes that catalyze hydroxylation of leukotriene B4 (LTB4. CYP4F18 has an unusual expression in neutrophils and was predicted to play a role in regulating LTB4-dependent inflammation. We compared chemotaxis of wild-type and Cyp4f18 knockout neutrophils using an in vitro assay. There was no significant difference in the chemotactic response to LTB4, but the response to complement component C5a increased 1.9–2.25-fold in knockout cells compared to wild-type (P < 0.01. This increase was still observed when neutrophils were treated with inhibitors of eicosanoid synthesis. There were no changes in expression of other CYP4 enzymes in knockout neutrophils that might compensate for loss of CYP4F18 or lead to differences in activity. A mouse model of dextran sodium sulfate colitis was used to investigate the consequences of increased C5a-dependent chemotaxis in vivo, but there was no significant difference in weight loss, disease activity, or colonic tissue myeloperoxidase between wild-type and Cyp4f18 knockout mice. This study demonstrates the limitations of inferring CYP4F function based on an ability to use LTB4 as a substrate, points to expanding roles for CYP4F enzymes in immune regulation, and underscores the in vivo challenges of CYP knockout studies.

  7. [Major complement inhibiting factors from the venom of the Central Asian cobra Naja naja oxiana].

    Science.gov (United States)

    Kozlov, L V; Shoĭbonov, B B; Antonov, V K

    1989-11-01

    The properties of two anticomplementic factors isolated by CM-Sepharose chromatography from the basic non-adsorbed on DEAE-Sepharose fraction of the Central Asian cobra Naja naja oxiana venom, were studied. Of these three factors (CFB-I, CFB-II and CFB-III) the latter had been characterized earlier. CFB-I was shown to be a protein with an N-terminal Asp and a molecular mass of about 39 kDa (data from gel chromatography); its content in the venom is 3.6 mg/g of dry venom. The protein inhibits mainly the classical pathway of the complement activation, being bound to component C4 (Ki = 9 nM). CFB-I seems to be analogous to the CI inhibitor from the venom of the Naja haje cobra. An analysis of the N-terminal sequence of CFB-II showed it to be identical to the earlier characterized cytotoxin I. CFB-I inhibits the formation of C3 convertase with Ki = 2.2-2.8 microM by way of binding to C4b and thus interfering with the component C2 sorption.

  8. Primary complement C5 deficiencies - molecular characterization and clinical review of two families.

    Science.gov (United States)

    Schejbel, Lone; Fadnes, Dag; Permin, Henrik; Lappegård, Knut Tore; Garred, Peter; Mollnes, Tom Eirik

    2013-10-01

    Inherited deficiency states of the terminal complement component C5 are rare and often associated with increased risk of recurrent Neisseria infections. More than 50 cases with primary C5 deficiency have been reported. In spite of this, the molecular basis has only been documented in a few cases. In the present study we investigated two unrelated Caucasian probands with C5 deficiency originating from Norway and Denmark, respectively, and found three previously undescribed mutations. With these data, thirteen mutations associated with C5 deficiency have been described. By genetic screening of the family of the Norwegian patient, previously diagnosed as homozygous C5 deficient and suffering four Neisseria infections, an additional case of C5 deficiency was discovered, who had experienced one episode of Neisseria infections. Detailed review of the clinical history of the patients and their healthy relatives did not reveal any differences between C5 deficient and sufficient individuals with regard to clinical presentation, apart from the susceptibility to Neisseria infections. Of note, one of the patients described here, and several C5 deficient patients from the literature had Neisseria meningitidis serotype B infections, which is not covered by the current vaccines. These data support the clinical guidelines for patients treated with C5 inhibitors, who are functional C5 deficient by the treatment. Copyright © 2013 Elsevier GmbH. All rights reserved.

  9. Substrate recognition by complement convertases revealed in the C5–cobra venom factor complex

    Science.gov (United States)

    Laursen, Nick S; Andersen, Kasper R; Braren, Ingke; Spillner, Edzard; Sottrup-Jensen, Lars; Andersen, Gregers R

    2011-01-01

    Complement acts as a danger-sensing system in the innate immune system, and its activation initiates a strong inflammatory response and cleavage of the proteins C3 and C5 by proteolytic enzymes, the convertases. These contain a non-catalytic substrate contacting subunit (C3b or C4b) in complex with a protease subunit (Bb or C2a). We determined the crystal structures of the C3b homologue cobra venom factor (CVF) in complex with C5, and in complex with C5 and the inhibitor SSL7 at 4.3 Å resolution. The structures reveal a parallel two-point attachment between C5 and CVF, where the presence of SSL7 only slightly affects the C5–CVF interface, explaining the IgA dependence for SSL7-mediated inhibition of C5 cleavage. CVF functions as a relatively rigid binding scaffold inducing a conformational change in C5, which positions its cleavage site in proximity to the serine protease Bb. A general model for substrate recognition by the convertases is presented based on the C5–CVF and C3b–Bb–SCIN structures. Prior knowledge concerning interactions between the endogenous convertases and their substrates is rationalized by this model. PMID:21217642

  10. Dysregulated Complement Activation as a Common Pathway of Injury in Preeclampsia and Other Pregnancy Complications

    OpenAIRE

    Lynch, Anne M.; Salmon, Jane E.

    2010-01-01

    The complement system protects the host against invading organisms, initiates inflammation and dispose of immune complexes and the products of inflammatory injury. The complement system provides an important link between the innate and adaptive immune systems. Experimental observations suggest that increased complement activation causes and/or perpetuates inflammation during pregnancy. Recent studies suggest a link between complement activation and preeclampsia. Excessive activation or insuff...

  11. Complement and Antibody-Mediated Enhancement of Erythrocyte Invasion by Plasmodium Falciparum

    Science.gov (United States)

    2016-04-01

    Keywords: Malaria Complement Red blood cells Merozoites CR11. Introduction Malaria , a mosquito-borne infectious disease caused by eukaryotic intracellular... malaria kills hundreds of thousands of people every year. A vaccine that blocks red blood cell (RBC) invasion has been an elusive goal. Although...to use complement to invade RBCs and, thus, hijack the complement system and evade the host immune response. 15. SUBJECT TERMS Malaria , complement

  12. [Acquired coagulant factor inhibitors].

    Science.gov (United States)

    Nogami, Keiji

    2015-02-01

    Acquired coagulation factor inhibitors are an autoimmune disease causing bleeding symptoms due to decreases in the corresponding factor (s) which result from the appearance of autoantibodies against coagulation factors (inhibitor). This disease is quite different from congenital coagulation factor deficiencies based on genetic abnormalities. In recent years, cases with this disease have been increasing, and most have anti-factor VIII autoantibodies. The breakdown of the immune control mechanism is speculated to cause this disease since it is common in the elderly, but the pathology and pathogenesis are presently unclear. We herein describe the pathology and pathogenesis of factor VIII and factor V inhibitors. Characterization of these inhibitors leads to further analysis of the coagulation process and the activation mechanisms of clotting factors. In the future, with the development of new clotting examination method (s), we anticipate that further novel findings will be obtained in this field through inhibitor analysis. In addition, detailed elucidation of the coagulation inhibitory mechanism possibly leading to hemostatic treatment strategies for acquired coagulation factor disorders will be developed.

  13. 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.

  14. Upregulation of Early and Downregulation of Terminal Pathway Complement Genes in Subcutaneous Adipose Tissue and Adipocytes in Acquired Obesity

    Directory of Open Access Journals (Sweden)

    Sanna Kaye

    2017-05-01

    Full Text Available Inflammation is an important mediator of obesity-related complications such as the metabolic syndrome but its causes and mechanisms are unknown. As the complement system is a key mediator of inflammation, we studied whether it is activated in acquired obesity in subcutaneous adipose tissue (AT and isolated adipocytes. We used a special study design of genetically matched controls of lean and heavy groups, rare monozygotic twin pairs discordant for body mass index (BMI [n = 26, within-pair difference (Δ in body mass index, BMI >3 kg/m2] with as much as 18 kg mean Δweight. Additionally, 14 BMI-concordant (BMI <3 kg/m2 served as a reference group. The detailed measurements included body composition (DEXA, fat distribution (MRI, glucose, insulin, adipokines, C3a and SC5b-9 levels, and the expression of complement and insulin signaling pathway-related genes in AT and adipocytes. In both AT and isolated adipocytes, the classical and alternative pathway genes were upregulated, and the terminal pathway genes downregulated in the heavier co-twins of the BMI-discordant pairs. The upregulated genes included C1q, C1s, C2, ficolin-1, factor H, receptors for C3a and C5a (C5aR1, and the iC3b receptor (CR3. While the terminal pathway components C5 and C6 were downregulated, its inhibitor clusterin was upregulated. Complement gene upregulation in AT and adipocytes correlated positively with adiposity and hyperinsulinemia and negatively with the expression of insulin signaling-related genes. Plasma C3a, but not SC5b-9, levels were elevated in the heavier co-twins. There were no differences between the co-twins in BMI-concordant pairs. Obesity is associated with increased expression of the early, but not late, complement pathway components and of key receptors. The twins with acquired obesity have therefore an inflated inflammatory activity in the AT. The results suggest that complement is likely involved in orchestrating clearance of apoptotic debris

  15. Mannose-binding lectin is a critical factor in systemic complement activation during meningococcal septic shock.

    NARCIS (Netherlands)

    Sprong, T.; Mollnes, T.E.; Neeleman, C.; Swinkels, D.W.; Netea, M.G.; Meer, J.W.M. van der; Deuren, M. van

    2009-01-01

    BACKGROUND: Systemic activation of complement during meningococcal disease is associated with severe disease and poor outcome. The exact mechanism of activation of complement is unknown but is important for future therapies aimed at modulating the complement system in this disease. METHODS: We

  16. The complement system as a potential therapeutic target in rheumatic disease.

    Science.gov (United States)

    Trouw, Leendert A; Pickering, Matthew C; Blom, Anna M

    2017-09-01

    Complement activation is associated with common rheumatic diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and systemic vasculitis. Evidence linking complement activation to these diseases includes the presence of complement deposition in affected tissues, decreased levels of complement proteins and high levels of complement activation fragments in the blood and/or synovial fluid of patients with these diseases, as well as data from experimental models. Eculizumab, a monoclonal antibody that inhibits the complement component C5, is now approved for the treatment of rare conditions involving complement hyperactivation, and the success of this therapy has renewed interest in understanding the utility of complement inhibition in rheumatological practice, particularly for SLE. For example, inhibiting C5 is a potential means of reducing glomerular inflammation in lupus nephritis or treating thrombotic microangiopathy in SLE. The complement system is one of multiple mediators of tissue injury in complex diseases such as SLE, and identifying the disease context in which complement activation has a predominant role is a challenge. An added difficulty in RA is identifying a role for therapeutic complement inhibition within the diverse treatment modalities already available. In this Review, evidence for the therapeutic potential of complement manipulation in rheumatology practice is evaluated.

  17. 21 CFR 866.5260 - Complement C3b inactivator immunological test system.

    Science.gov (United States)

    2010-04-01

    ... Systems § 866.5260 Complement C3b inactivator immunological test system. (a) Identification. A complement... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Complement C3b inactivator immunological test system. 866.5260 Section 866.5260 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

  18. DMPD: Complement-mediated phagocytosis--the role of Syk. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16754322 Complement-mediated phagocytosis--the role of Syk. Tohyama Y, Yamamura H. ...IUBMB Life. 2006 May-Jun;58(5-6):304-8. (.png) (.svg) (.html) (.csml) Show Complement-mediated phagocytosis-...-the role of Syk. PubmedID 16754322 Title Complement-mediated phagocytosis--the role of Syk. Authors Tohyama

  19. Circulating AIM Prevents Hepatocellular Carcinoma through Complement Activation

    Directory of Open Access Journals (Sweden)

    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.

  20. Identification of the Fanconi Anemia Complementation Group I Gene, FANCI

    Directory of Open Access Journals (Sweden)

    Josephine C. Dorsman

    2007-01-01

    Full Text Available To identify the gene underlying Fanconi anemia (FA complementation group I we studied informative FA-I families by a genome-wide linkage analysis, which resulted in 4 candidate regions together encompassing 351 genes. Candidates were selected via bioinformatics and data mining on the basis of their resemblance to other FA genes/proteins acting in the FA pathway, such as: degree of evolutionary conservation, presence of nuclear localization signals and pattern of tissue-dependent expression. We found a candidate, KIAA1794 on chromosome 15q25-26, to be mutated in 8 affected individuals previously assigned to complementation group I. Western blots of endogenous FANCI indicated that functionally active KIAA1794 protein is lacking in FA-I individuals. Knock-down of KIAA1794 expression by siRNA in HeLa cells caused excessive chromosomal breakage induced by mitomycin C, a hallmark of FA cells. Furthermore, phenotypic reversion of a patient-derived cell line was associated with a secondary genetic alteration at the KIAA1794 locus. These data add up to two conclusions. First, KIAA1794 is a FA gene. Second, this gene is identical to FANCI, since the patient cell lines found mutated in this study included the reference cell line for group I, EUFA592.

  1. Complement factor C5a induces atherosclerotic plaque disruptions

    Science.gov (United States)

    Wezel, Anouk; de Vries, Margreet R; Lagraauw, H Maxime; Foks, Amanda C; Kuiper, Johan; Quax, Paul HA; Bot, Ilze

    2014-01-01

    Complement factor C5a and its receptor C5aR are expressed in vulnerable atherosclerotic plaques; however, a causal relation between C5a and plaque rupture has not been established yet. Accelerated atherosclerosis was induced by placing vein grafts in male apoE−/− mice. After 24 days, when advanced plaques had developed, C5a or PBS was applied locally at the lesion site in a pluronic gel. Three days later mice were killed to examine the acute effect of C5a on late stage atherosclerosis. A significant increase in C5aR in the plaque was detectable in mice treated with C5a. Lesion size and plaque morphology did not differ between treatment groups, but interestingly, local treatment with C5a resulted in a striking increase in the amount of plaque disruptions with concomitant intraplaque haemorrhage. To identify the potential underlying mechanisms, smooth muscle cells and endothelial cells were treated in vitro with C5a. Both cell types revealed a marked increase in apoptosis after stimulation with C5a, which may contribute to lesion instability in vivo. Indeed, apoptosis within the plaque was seen to be significantly increased after C5a treatment. We here demonstrate a causal role for C5a in atherosclerotic plaque disruptions, probably by inducing apoptosis. Therefore, intervention in complement factor C5a signalling may be a promising target in the prevention of acute atherosclerotic complications. PMID:25124749

  2. A Small Group Activity About Bacterial Regulation And Complementation

    Directory of Open Access Journals (Sweden)

    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.

  3. A small group activity about bacterial regulation and complementation.

    Science.gov (United States)

    Merkel, Susan; Hanson, Buck; Parks, Adam

    2010-01-01

    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.

  4. Entailments, pragmatic assertion and mood in Spanish complements

    Directory of Open Access Journals (Sweden)

    Errapel Mejías-Bikandi

    2016-06-01

    Full Text Available This paper examines a frequently overlooked class of expressions in Spanish that license the subjunctive mood in a complement clause. This class contains expressions such as poco/a/s “few”, menos de “less than” and solo “only”. The goal of the paper is to offer an account of the use of mood with these expressions that incorporates the data under discussion into previous pragmatic accounts of mood based on notions of assertion and informative value. The paper first offers a semantic characterization of this class of expressions that is based on their monotonic properties (Ladusaw 1980, Ladusaw 1983. Next, it explores the pragmatic effects of their semantic properties. Following Stalnaker (1978, I assume that the effect of a pragmatic assertion is to reduce the set of possible worlds that represents the presuppositions held by a speaker and their audience (referred to as the context set. It is argued that propositions under the scope of an upward entailing expression are more informative, and they are thus more relevant and higher in a scale of assertability (Lunn 1989, in that they allow for inferences that further reduce the context set. Propositions under the scope of expressions that are not upward entailing lose some of their informative value, and thus they are lower in the scale of assertability, which correlates with the possibility of using subjunctive mood in a complement under their scope.

  5. 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

    receptors and regulatory proteins on B cells from SLE patients, as well as the deposition of C3 fragments occurring in vivo or after in vitro AP activation. We have confirmed, for a proportion of the patients studied, reduced expression of CR1 and CR2 on B cells, and shown a consistency between low CR2...... activation by B cells in homologous serum. Finally, we demonstrated an inverse relationship between SLE disease activity index (SLEDAI) and the expression of complement receptor 2 (CR2) on SLE B cells. Thus, determination of CR2 on B cells may emerge as an additional laboratory tool in the assessment of SLE...

  6. Cathepsin D inhibitors

    Directory of Open Access Journals (Sweden)

    M. Gacko

    2007-11-01

    Full Text Available Inhibitors of cathepsin D belong to chemical compounds that estrify carboxyl groups of the Asp33 and Asp231residues of its catalytic site, penta-peptides containing statin, i.e. the amino acid similar in structure to the tetraedric indirectproduct, and polypeptides found in the spare organs of many plants and forming permanent noncovalent complexes withcathepsin. Cathepsin D activity is also inhibited by alpha2-macroglobulin and antibodies directed against this enzyme.Methods used to determine the activity and concentration of these inhibitors and their analytical, preparative and therapeuticapplications are discussed.

  7. Factor J, an inhibitor of the complement classical pathway: the quantitation by an ELISA inhibition assay in normal human serum.

    Science.gov (United States)

    Jiménez-Clavero, M A; González-Rubio, C; Fontán, G; López-Trascasa, M

    1994-06-01

    Factor J (FJ) is a protein present in human serum, with inhibitory activity against C1. Here we describe the quantitation of FJ in human serum by means of an ELISA inhibition assay. We have purified FJ from the urine of a normal donor following a previously published method with slight modifications. Polyclonal anti-FJ antibodies have been raised in rabbits immunized with a single dose of purified antigen injected in multiple sites. IgG from polyclonal FJ antiserum, coupled to a solid matrix (Affi-Prep gel) was able to adsorb purified FJ antigenically and functionally. Furthermore, anti-FJ specifically retained serum components antigenically related with urine FJ. Taking into account this reactivity, we have developed an inhibition enzyme-linked immunosorbent assay (ELISA) useful for measuring FJ levels in normal human serum. This immunoassay involves preincubating polyclonal anti-FJ with different dilutions of normal human serum to quantitatively reduce the antibody available to bind to purified FJ-coated microtiter plates. Binding of remaining antibody to the microtiter plate is measured spectrophotometrically using peroxidase-conjugated secondary antibody. Quantitation is accomplished by comparison with a known quantity of purified FJ. Conditions for optimization of this quantitative assay have been assessed, including trials with different blocking agents, of which nonfat milk gave the best results. Preliminary experiments showed the existence of paradoxical effects, that is, high nonspecific binding at high serum dilutions. We have eliminated these effects by including high ionic strength (0.4 M NaCl) in the sample incubation solution. Sensitivity and reproducibility parameters have also been established. FJ levels have been measured for the first time in sera from 86 healthy donors.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Changes in blood levels of proteinase inhibitors, pregnancy zone protein, steroid carriers and complement factors induced by oral contraceptives

    DEFF Research Database (Denmark)

    Nielsen, C H; Poulsen, H K; Teisner, B

    1993-01-01

    Three low-dose oral contraceptives Trinordiol, Gynatrol, and Marvelon, containing ethinylestradiol (EE) in combination with triphasic levonorgestrel (LNg), monophasic levonorgestrel, and monophasic desogestrel (DGS), respectively, were given to 65 healthy women, n = 21-22 in each group. Blood...

  9. Bimolecular Complementation to Visualize Filovirus VP40-Host Complexes in Live Mammalian Cells: Toward the Identification of Budding Inhibitors

    Science.gov (United States)

    2011-01-01

    Virology [20] J. Martin -Serrano, T. Zang, and P. D. Bieniasz, “Role of ESCRT-I in retroviral budding,” The Journal of Virology, vol. 77, no. 8, pp...4794–4804, 2003. [21] J. Martin -Serrano, T. Zang, and P. D. Bieniasz, “HIV-1 and Ebola virus encode small peptide motifs that recruit Tsg101 to sites of...with the PTAP motif of the HIV-1 p6 protein,” Nature Structural Biology, vol. 9, no. 11, pp. 812–817, 2002. [38] G. M. Morris, H. Ruth, W. Lindstrom et

  10. Gentamicin Binds to Megalin as a Competitive Inhibitor Using the Common Ligand Binding Motif of Complement Type Repeats

    DEFF Research Database (Denmark)

    Dagil, Robert; O'Shea, Charlotte; Nykjaer, Anders

    2012-01-01

    Gentamicin is an aminoglycoside widely used in treatments of, in particular, enterococcal, mycobacterial, and severe Gram-negative bacterial infections. Large doses of gentamicin cause nephrotoxicity and ototoxicity, entering the cell via the receptor megalin. Until now, no structural information...

  11. Changes in blood levels of proteinase inhibitors, pregnancy zone protein, steroid carriers and complement factors induced by oral contraceptives

    DEFF Research Database (Denmark)

    Nielsen, Claus Henrik; Poulsen, Henning Kvist; Teisner, Børge

    1993-01-01

    Three low-dose oral contraceptives Trinordiol, Gynatrol, and Marvelon, containing ethinylestradiol (EE) in combination with triphasic levonorgestrel (LNg), monophasic levonorgestrel, and monophasic desogestrel (DGS), respectively, were given to 65 healthy women, n = 21-22 in each group. Blood lev...

  12. Inhibitors of histone demethylases

    DEFF Research Database (Denmark)

    Lohse, Brian; Kristensen, Jesper L; Kristensen, Line H

    2011-01-01

    Methylated lysines are important epigenetic marks. The enzymes involved in demethylation have recently been discovered and found to be involved in cancer development and progression. Despite the relative recent discovery of these enzymes a number of inhibitors have already appeared. Most of the i...

  13. Protease inhibitors and beyond.

    Science.gov (United States)

    1997-03-01

    A new generation of protease inhibitors is entering studies. Abbott Lab's ABT-378 and Pharmacia/Upjohn's PNU-140690 are beginning clinical studies and both are designed to overcome resistance problems. Several companies are developing new compounds to inhibit reverse transcriptase, such as Bristol-Myers Squibb's lobucavir and Hoechst/Bayer's HBY097. Calanolide A, which will soon begin trials, has a different resistance pattern than other non-nucleoside reverse transcriptase inhibitors, which may be an important advantage. Several groups are developing compounds to inhibit the HIV zinc finger, such as Parke-Davis' compound, CI-1012; and a Dutch company who is developing Azodicarbonamide, a drug currently in phase I/II trials for people with advanced disease in Europe. HIV drugs to date have not been successful in blocking viral fusion. However, three new fusion inhibitors are showing promise within the laboratory: Pentafuside (currently in phase I trials), Fuji ImmunoPharmaceuticals' FP-21399 (currently in phase I trials), and ISIS Pharmaceuticals' ISIS 5320. A new class of drugs known as integrase inhibitors has been of interest to pharmaceutical companies for the past several years; only one drug, Aronex Pharmaceuticals' Zintevir, has reached phase I/II trials.

  14. Transglutaminase inhibitor from milk

    NARCIS (Netherlands)

    Jong, G.A.H. de; Wijngaards, G.; Koppelman, S.J.

    2003-01-01

    Cross-linking experiments of skimmed bovine milk with bacterial transglutaminase isolated from Streptoverticillium mobaraense showed only some degree of formation of high-molecular-weight casein polymers. Studies on the nature of this phenomenon revealed that bovine milk contains an inhibitor of

  15. HIV protease inhibitor resistance

    NARCIS (Netherlands)

    Wensing, Annemarie M.J.; Fun, Axel; Nijhuis, Monique

    2017-01-01

    HIV protease is pivotal in the viral replication cycle and directs the formation of mature infectious virus particles. The development of highly specific HIV protease inhibitors (PIs), based on thorough understanding of the structure of HIV protease and its substrate, serves as a prime example of

  16. Phosphodiesterase 4 inhibitors.

    Science.gov (United States)

    Zebda, Rema; Paller, Amy S

    2018-03-01

    Historically, drugs available for treating atopic dermatitis (AD) have been limited to topical corticosteroids and topical calcineurin inhibitors, with systemic immunosuppressants and phototherapy reserved for severe AD. Despite their efficacy and infrequent adverse events, phobia about the use of topical steroids and calcineurin inhibitors has limited their use. More targeted options with fewer systemic and cutaneous side effects are needed for treating AD. Phosphodiesterase 4 (PDE4) is involved in the regulation of proinflammatory cytokines via the degradation of cyclic adenosine monophosphate. PDE4 activity is increased in the inflammatory cells of patients with AD, leading to increased production of proinflammatory cytokines and chemokines. Targeting PDE4 reduces the production of these proinflammatory mediators in AD. Both topical and oral PDE4 inhibitors have a favorable safety profile. Crisaborole 2% ointment, a topical PDE4, is now US Food and Drug Administration-approved for children older than 2 years and adults in the treatment of AD. Crisaborole 2% ointment shows early and sustained improvement in disease severity and pruritus and other AD symptoms, with burning and/or stinging upon application as the only related adverse event. Other PDE4 inhibitors are currently in trials with promising efficacy and safety. Copyright © 2017. Published by Elsevier Inc.

  17. Proton-pump inhibitors

    African Journals Online (AJOL)

    Proton-pump inhibitors (PPIs) work by binding irreversibly to the. H+/K+-ATPase pump of the parietal cell, leading to inhibition of acid production in approximately 70% of active pumps.1The result is a dramatic increase in gastric pH mitigating the deleterious effects of acid in gastro-oesophageal reflux disease (GORD) and.

  18. Direct, Indirect and Inferred Causation: Finite and Infinitive Complements of Deixar and Fazer

    Directory of Open Access Journals (Sweden)

    Rainer Vesterinen

    2008-06-01

    Full Text Available The present article examines the variation between finite and infinitive complements of the two Portuguese causation verbs deixar and fazer from a cognitive perspective. It is argued that the difference between these complements is mainly semantic and that it can be explained by the notion of linguistic iconicity, i.e. the semantic differences can be seen in the formal differences. Accordingly, a minor formal distance between the main verb and the complement verb in the infinitive complements signals a prototypically direct causation. On the other hand, a greater distance in the finite complements implies an indirect causation. Further, it is claimed that the indirect causation is often of an inferential and more complex character, thus giving rise to a higher degree of subjectification in the finite complements than in the infinitive complements.

  19. Complement factor H deficiency results in decreased neuroretinal expression of Cd59a in aged mice

    DEFF Research Database (Denmark)

    Faber, Carsten; Williams, Jennifer; Juel, Helene Bæk

    2012-01-01

    Purpose. The complement system is closely linked to the pathogenesis of AMD. Several complement genes are expressed in RPE, and complement proteins accumulate in drusen. Further, a common variant of complement factor H (CFH) confers increased risk of developing AMD. Because the mechanisms by which...... changes in the function of CFH influence development of AMD are unclear, we examined ocular complement expression as a consequence of age in control and CFH null mutant mice. Methods. Gene expression in neuroretinas and RPE/choroid from young and aged WT and Cfh−/− C57BL/6J mice was analyzed...... by microarrays. Expression of a wide range of complement genes was compared with expression in liver. Results. An age-associated increased expression of complement, particularly C1q, C3, and factor B, in the RPE/choroid coincided with increased expression of the negative regulators Cfh and Cd59a...

  20. [Alterations of the complement system in patients with catastrophic antiphospholipid syndrome].

    Science.gov (United States)

    Dem'ianova, K A; Kozlovskaia, N L; Shilov, E M; Bobrova, L A; Kozlov, L V; Sorokin, Iu D; Roshchupkina, S V; Nikiforova, N V; Dobrosmyslov, I A; Romanova, M D

    2014-01-01

    To investigate alterations of the complement system in patients with catastrophic antiphospholipid syndrome (CAPS). Four patients (2 men aged 23 and 40 years and 2 women aged 39 and 58 years) diagnosed as having CAPS, including 3 patients with systemic lupus erythematosus and secondary antiphospholipid syndrome (APS) and 1 patient with primary APS, were examined. The activity of the complement components C1-C5 and total hemolytic activity were determined in all the patients at the moment of an acute episode and in 1 patient after treatment. The activity of the studied complement components and total hemolytic complement activity proved to be significantly decreased in all the patients. That of complement components recovered after treatment using fresh frozen plasma. The possibility and mechanisms of complement system activation in the patients with CAPS are discussed. The preliminary results obtained by the examination of few cases may lead to the conclusion that the complement system may be involved in the development of CAPS.

  1. Complement alternative pathway activation in human nonalcoholic steatohepatitis.

    Directory of Open Access Journals (Sweden)

    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

  2. Manipulation of the Complement System for Benefit in Sepsis

    Directory of Open Access Journals (Sweden)

    Peter A. Ward

    2012-01-01

    Full Text Available There is evidence in sepsis, both in rodents and in humans, that activation of the complement system results in excessive production of C5a, which triggers a series of events leading to septic shock, multiorgan failure, and lethality. In rodents following cecal ligation and puncture (CLP, which induces polymicrobial sepsis, in vivo blockade of C5a using neutralizing antibodies dramatically improved survival, reduced apoptosis of lymphoid cells, and attenuated the ensuing coagulopathy. Based on these data, it seems reasonable to consider therapeutic blockade of C5a in humans entering into sepsis and septic shock. Strategies for the development of such an antibody for use in humans are presented.

  3. Inhibition of human complement components by Loxosceles reclusa venom.

    Science.gov (United States)

    Futrell, J M; Morgan, P N

    1978-01-01

    Venom from the brown recluse spider, Loxosceles reclusa, was capable of inactivation human C1-C7 in vitro. This inactivation occurred if venom was added to fresh adult human serum, human cord serum, or functionally pure specific human components. Optimal incubation conditions for the inactivation of each component were determined and were found generally to be in the range of 25 or 37 degrees C for 30-60 min. The alternative complement pathway did not appear to be involved, since C1, C4, and C2 were readily inactivated, and inactivation took place in sera depleted of factor B of the properdin system. Venom-induced inactivation appeared to require few, if any, serum cofactors, because, with the possible exception of C2, functionally pure components, as well as those in sera, were readily inactivated.

  4. Graphs cospectral with a friendship graph or its complement

    Directory of Open Access Journals (Sweden)

    Alireza Abdollahi

    2013-12-01

    Full Text Available Let $n$ be any positive integer and let $F_n$ be the friendship (or Dutch windmill graph with $2n+1$ vertices and $3n$ edges. Here we study graphs with the same adjacency spectrum as the $F_n$. Two graphs are called cospectral if the eigenvalues multiset of their adjacency matrices are the same. Let $G$ be a graph cospectral with $F_n$. Here we prove that if $G$ has no cycle of length $4$ or $5$, then $Gcong F_n$. Moreover if $G$ is connected and planar then $Gcong F_n$.All but one of connected components of $G$ are isomorphic to $K_2$.The complement $overline{F_n}$ of the friendship graph is determined by its adjacency eigenvalues, that is, if $overline{F_n}$ is cospectral with a graph $H$, then $Hcong overline{F_n}$.

  5. Complement-Mediated Regulation of Apolipoprotein E in Cultured Human RPE Cells.

    Science.gov (United States)

    Yang, Ping; Skiba, Nikolai P; Tewkesbury, Grace M; Treboschi, Victoria M; Baciu, Peter; Jaffe, Glenn J

    2017-06-01

    Complement activation is implicated in the pathogenesis of age-related macular degeneration (AMD). Apolipoprotein E (ApoE) and complement activation products such as membrane attack complex (MAC) are present in eyes of individuals with AMD. Herein, we investigated the effect of complement activation on induction of ApoE accumulation in human retinal pigment epithelial (RPE) cells. Cultured human RPE cells were primed with a complement-fixing antibody followed by treatment with C1q-depleted (C1q-Dep) human serum to elicit alternative pathway complement activation. Controls included anti-C5 antibody-treated serum and heat-inactivated C1q-Dep. Total protein was determined on RPE cell extracts, conditioned media, and extracellular matrix (ECM) by Western blot. ApoE and MAC colocalization was assessed on cultured RPE cells and human eyes by immunofluorescent stain. ApoE mRNA expression was evaluated by quantitative PCR (qPCR). Complement challenge upregulated cell-associated ApoE, but not apolipoprotein A1. ApoE accumulation was blocked by anti-C5 antibody and enhanced by repetitive complement challenge. ApoE mRNA levels were not affected by complement challenge. ApoE was frequently colocalized with MAC in complement-treated cells and drusen from human eyes. ApoE was released into complement-treated conditioned media after a single complement challenge and accumulated on ECM after repetitive complement challenge. Complement challenge induces time-dependent ApoE accumulation in RPE cells. An understanding of the mechanisms by which complement affects RPE ApoE accumulation may help to better explain drusen composition, and provide insights into potential therapeutic targets.

  6. 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.

  7. HOX gene complement and expression in the planarian Schmidtea mediterranea

    Directory of Open Access Journals (Sweden)

    Ko W. Currie

    2016-03-01

    Full Text Available Abstract Background Freshwater planarians are well known for their regenerative abilities. Less well known is how planarians maintain spatial patterning in long-lived adult animals or how they re-pattern tissues during regeneration. HOX genes are good candidates to regulate planarian spatial patterning, yet the full complement or genomic clustering of planarian HOX genes has not yet been described, primarily because only a few have been detectable by in situ hybridization, and none have given morphological phenotypes when knocked down by RNAi. Results Because the planarian Schmidtea mediterranea (S. mediterranea is unsegmented, appendage less, and morphologically simple, it has been proposed that it may have a simplified HOX gene complement. Here, we argue against this hypothesis and show that S. mediterranea has a total of 13 HOX genes, which represent homologs to all major axial categories, and can be detected by whole-mount in situ hybridization using a highly sensitive method. In addition, we show that planarian HOX genes do not cluster in the genome, yet 5/13 have retained aspects of axially restricted expression. Finally, we confirm HOX gene axial expression by RNA deep-sequencing 6 anterior–posterior “zones” of the animal, which we provide as a dataset to the community to discover other axially restricted transcripts. Conclusions Freshwater planarians have an unappreciated HOX gene complexity, with all major axial categories represented. However, we conclude based on adult expression patterns that planarians have a derived body plan and their asexual lifestyle may have allowed for large changes in HOX expression from the last common ancestor between arthropods, flatworms, and vertebrates. Using our in situ method and axial zone RNAseq data, it should be possible to further understand the pathways that pattern the anterior–posterior axis of adult planarians.

  8. Complement factor C5a induces atherosclerotic plaque disruptions.

    Science.gov (United States)

    Wezel, Anouk; de Vries, Margreet R; Lagraauw, H Maxime; Foks, Amanda C; Kuiper, Johan; Quax, Paul H A; Bot, Ilze

    2014-10-01

    Complement factor C5a and its receptor C5aR are expressed in vulnerable atherosclerotic plaques; however, a causal relation between C5a and plaque rupture has not been established yet. Accelerated atherosclerosis was induced by placing vein grafts in male apoE(-/-) mice. After 24 days, when advanced plaques had developed, C5a or PBS was applied locally at the lesion site in a pluronic gel. Three days later mice were killed to examine the acute effect of C5a on late stage atherosclerosis. A significant increase in C5aR in the plaque was detectable in mice treated with C5a. Lesion size and plaque morphology did not differ between treatment groups, but interestingly, local treatment with C5a resulted in a striking increase in the amount of plaque disruptions with concomitant intraplaque haemorrhage. To identify the potential underlying mechanisms, smooth muscle cells and endothelial cells were treated in vitro with C5a. Both cell types revealed a marked increase in apoptosis after stimulation with C5a, which may contribute to lesion instability in vivo. Indeed, apoptosis within the plaque was seen to be significantly increased after C5a treatment. We here demonstrate a causal role for C5a in atherosclerotic plaque disruptions, probably by inducing apoptosis. Therefore, intervention in complement factor C5a signalling may be a promising target in the prevention of acute atherosclerotic complications. © 2014 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  9. HOX gene complement and expression in the planarian Schmidtea mediterranea.

    Science.gov (United States)

    Currie, Ko W; Brown, David D R; Zhu, Shujun; Xu, ChangJiang; Voisin, Veronique; Bader, Gary D; Pearson, Bret J

    2016-01-01

    Freshwater planarians are well known for their regenerative abilities. Less well known is how planarians maintain spatial patterning in long-lived adult animals or how they re-pattern tissues during regeneration. HOX genes are good candidates to regulate planarian spatial patterning, yet the full complement or genomic clustering of planarian HOX genes has not yet been described, primarily because only a few have been detectable by in situ hybridization, and none have given morphological phenotypes when knocked down by RNAi. Because the planarian Schmidtea mediterranea (S. mediterranea) is unsegmented, appendage less, and morphologically simple, it has been proposed that it may have a simplified HOX gene complement. Here, we argue against this hypothesis and show that S. mediterranea has a total of 13 HOX genes, which represent homologs to all major axial categories, and can be detected by whole-mount in situ hybridization using a highly sensitive method. In addition, we show that planarian HOX genes do not cluster in the genome, yet 5/13 have retained aspects of axially restricted expression. Finally, we confirm HOX gene axial expression by RNA deep-sequencing 6 anterior-posterior "zones" of the animal, which we provide as a dataset to the community to discover other axially restricted transcripts. Freshwater planarians have an unappreciated HOX gene complexity, with all major axial categories represented. However, we conclude based on adult expression patterns that planarians have a derived body plan and their asexual lifestyle may have allowed for large changes in HOX expression from the last common ancestor between arthropods, flatworms, and vertebrates. Using our in situ method and axial zone RNAseq data, it should be possible to further understand the pathways that pattern the anterior-posterior axis of adult planarians.

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

    OpenAIRE

    Kenedy, Melisha R.; Akins, Darrin R.

    2011-01-01

    Borrelia burgdorferi, the Lyme disease spirochete, binds the host complement inhibitors factor H (FH) and FH-like protein 1 (FHL-1). Binding of FH/FHL-1 by the B. burgdorferi proteins CspA and the OspE-related proteins is thought to enhance resistance to serum-mediated killing. While previous reports have shown that CspA confers serum resistance in B. burgdorferi, it is unclear whether the OspE-related proteins are relevant in B. burgdorferi serum resistance when OspE is expressed on the borr...

  11. Porcine complement regulators protect aortic smooth muscle cells poorly against human complement-induced lysis and proliferation: consequences for xenotransplantation.

    Science.gov (United States)

    Capey, Steven; van den Berg, Carmen W

    2005-05-01

    Accelerated atherosclerosis after transplantation has been observed and is characterized by smooth muscle cell proliferation in the graft. Porcine cells are frequently used in models of atherosclerosis and porcine organs are considered for use in transplantation. Complement (C) activation is known to play a major role in rejection of xenografts and is also considered to play a role in the development of atherosclerosis. The aim of this study was to investigate the expression and function of membrane bound regulators of complement (CReg) on porcine aortic smooth muscle cells (PASMC). The PASMC were assessed for expression of CReg and susceptibility to lysis by human C by flow-cytometry. The effect of various cytokines on CReg expression and C-susceptibility was investigated. The ability of human C to induce cell proliferation was assessed using the Alamar blue assay. The PASMC only express the CReg membrane cofactor protein (MCP) and CD59 on their cell surface. MCP expression was increased by interleukin (IL)-4. In contrast to porcine aortic endothelial cells (PAEC), PASMC were found to be surprisingly sensitive to C-mediated lysis, mainly due to a low level of expression of CD59. Human C-induced proliferation of PASMC, which was dependent on complete membrane attack complex (MAC) formation. Endogenously expressed CReg on PASMC poorly protect these cells to human C. Human C can induce proliferation of PASMC. In order to prevent accelerated atherosclerosis in porcine xenografts, increased levels of CReg not only have to be obtained on the endothelial cells but also on the smooth muscle cells.

  12. A pathogenic role of complement in arterial hypertension and hypertensive end organ damage.

    Science.gov (United States)

    Wenzel, Ulrich O; Bode, Marlies; Köhl, Jörg; Ehmke, Heimo

    2017-03-01

    The self-amplifying cascade of messenger and effector molecules of the complement system serves as a powerful danger-sensing system that protects the host from a hostile microbial environment, while maintaining proper tissue and organ function through effective clearance of altered or dying cells. As an important effector arm of innate immunity, it also plays important roles in the regulation of adaptive immunity. Innate and adaptive immune responses have been identified as crucial players in the pathogenesis of arterial hypertension and hypertensive end organ damage. In line with this view, complement activation may drive the pathology of hypertension and hypertensive injury through its impact on innate and adaptive immune responses. It is well known that complement activation can cause tissue inflammation and injury and complement-inhibitory drugs are effective treatments for several inflammatory diseases. In addition to these proinflammatory properties, complement cleavage fragments of C3 and C5 can exert anti-inflammatory effects that dampen the inflammatory response to injury. Recent experimental data strongly support a role for complement in arterial hypertension. The remarkably similar clinical and histopathological features of malignant nephrosclerosis and atypical hemolytic uremic syndrome, which is driven by complement activation, suggest a role for complement also in the development of malignant nephrosclerosis. Herein, we will review canonical and noncanonical pathways of complement activation as the framework to understand the multiple roles of complement in arterial hypertension and hypertensive end organ damage. Copyright © 2017 the American Physiological Society.

  13. Additive inhibition of complement deposition by pneumolysin and PspA facilitates Streptococcus pneumoniae septicemia.

    Science.gov (United States)

    Yuste, Jose; Botto, Marina; Paton, James C; Holden, David W; Brown, Jeremy S

    2005-08-01

    Streptococcus pneumoniae is a common cause of septicemia in the immunocompetent host. To establish infection, S. pneumoniae has to overcome host innate immune responses, one component of which is the complement system. Using isogenic bacterial mutant strains and complement-deficient immune naive mice, we show that the S. pneumoniae virulence factor pneumolysin prevents complement deposition on S. pneumoniae, mainly through effects on the classical pathway. In addition, using a double pspA-/ply- mutant strain we demonstrate that pneumolysin and the S. pneumoniae surface protein PspA act in concert to affect both classical and alternative complement pathway activity. As a result, the virulence of the pspA-/ply- strain in models of both systemic and pulmonary infection is greatly attenuated in wild-type mice but not complement deficient mice. The sensitivity of the pspA-/ply- strain to complement was exploited to demonstrate that although early innate immunity to S. pneumoniae during pulmonary infection is partially complement-dependent, the main effect of complement is to prevent spread of S. pneumoniae from the lungs to the blood. These data suggest that inhibition of complement deposition on S. pneumoniae by pneumolysin and PspA is essential for S. pneumoniae to successfully cause septicemia. Targeting mechanisms of complement inhibition could be an effective therapeutic strategy for patients with septicemia due to S. pneumoniae or other bacterial pathogens.

  14. The complement system in teleost fish: progress of post-homolog-hunting researches.

    Science.gov (United States)

    Nakao, Miki; Tsujikura, Masakazu; Ichiki, Satoko; Vo, Tam K; Somamoto, Tomonori

    2011-12-01

    Studies on the complement system of bony fish are now finishing a stage of homologue-hunting identification of the components, unveiling existence of almost all the orthologues of mammalian complement components in teleost. Genomic and transcriptomic data for several teleost species have contributed much for the homologue-hunting research progress. Only an exception is identification of orthologues of mammalian complement regulatory proteins and complement receptors. It is of particular interest that teleost complement components often exist as multiple isoforms with possible functional divergence. This review summarizes research progress of teleost complement system following the molecular identification and sequence analysis of the components. The findings of extensive expression analyses of the complement components with special emphasis of their prominent extrahepatic expression, acute-phase response to immunostimulation and various microbial infections, and ontogenic development including maternal transfer are discussed to infer teleost-specific functions of the complement system. Importance of the protein level characterization of the complement components is also emphasized, especially for understanding of the isotypic diversity of the components, a unique feature of teleost complement system. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Reciprocal complementation of the tumoricidal effects of radiation and natural killer cells.

    Directory of Open Access Journals (Sweden)

    Kai-Lin Yang

    Full Text Available The tumor microenvironment is a key determinant for radio-responsiveness. Immune cells play an important role in shaping tumor microenvironments; however, there is limited understanding of how natural killer (NK cells can enhance radiation effects. This study aimed to assess the mechanism of reciprocal complementation of radiation and NK cells on tumor killing. Various tumor cell lines were co-cultured with human primary NK cells or NK cell line (NK-92 for short periods and then exposed to irradiation. Cell proliferation, apoptosis and transwell assays were performed to assess apoptotic efficacy and cell viability. Western blot analysis and immunoprecipitation methods were used to determine XIAP (X-linked inhibitor of apoptosis protein and Smac (second mitochondria-derived activator of caspase expression and interaction in tumor cells. Co-culture did not induce apoptosis in tumor cells, but a time- and dose-dependent enhancing effect was found when co-cultured cells were irradiated. A key role for caspase activation via perforin/granzyme B (Grz B after cell-cell contact was determined, as the primary radiation enhancing effect. The efficacy of NK cell killing was attenuated by upregulation of XIAP to bind caspase-3 in tumor cells to escape apoptosis. Knockdown of XIAP effectively potentiated NK cell-mediated apoptosis. Radiation induced Smac released from mitochondria and neutralized XIAP and therefore increased the NK killing. Our findings suggest NK cells in tumor microenvironment have direct radiosensitization effect through Grz B injection while radiation enhances NK cytotoxicity through triggering Smac release.

  16. Complement regulator Factor H mediates a two-step uptake of Streptococcus pneumoniae by human cells.

    Science.gov (United States)

    Agarwal, Vaibhav; Asmat, Tauseef M; Luo, Shanshan; Jensch, Inga; Zipfel, Peter F; Hammerschmidt, Sven

    2010-07-23

    Streptococcus pneumoniae, a human pathogen, recruits complement regulator factor H to its bacterial cell surface. The bacterial PspC protein binds Factor H via short consensus repeats (SCR) 8-11 and SCR19-20. In this study, we define how bacterially bound Factor H promotes pneumococcal adherence to and uptake by epithelial cells or human polymorphonuclear leukocytes (PMNs) via a two-step process. First, pneumococcal adherence to epithelial cells was significantly reduced by heparin and dermatan sulfate. However, none of the glycosaminoglycans affected binding of Factor H to pneumococci. Adherence of pneumococci to human epithelial cells was inhibited by monoclonal antibodies recognizing SCR19-20 of Factor H suggesting that the C-terminal glycosaminoglycan-binding region of Factor H mediates the contact between pneumococci and human cells. Blocking of the integrin CR3 receptor, i.e. CD11b and CD18, of PMNs or CR3-expressing epithelial cells reduced significantly the interaction of pneumococci with both cell types. Similarly, an additional CR3 ligand, Pra1, derived from Candida albicans, blocked the interaction of pneumococci with PMNs. Strikingly, Pra1 inhibited also pneumococcal uptake by lung epithelial cells but not adherence. In addition, invasion of Factor H-coated pneumococci required the dynamics of host-cell actin microfilaments and was affected by inhibitors of protein-tyrosine kinases and phosphatidylinositol 3-kinase. In conclusion, pneumococcal entry into host cells via Factor H is based on a two-step mechanism. The first and initial contact of Factor H-coated pneumococci is mediated by glycosaminoglycans expressed on the surface of human cells, and the second step, pneumococcal uptake, is integrin-mediated and depends on host signaling molecules such as phosphatidylinositol 3-kinase.

  17. Complement Regulator Factor H Mediates a Two-step Uptake of Streptococcus pneumoniae by Human Cells*

    Science.gov (United States)

    Agarwal, Vaibhav; Asmat, Tauseef M.; Luo, Shanshan; Jensch, Inga; Zipfel, Peter F.; Hammerschmidt, Sven

    2010-01-01

    Streptococcus pneumoniae, a human pathogen, recruits complement regulator factor H to its bacterial cell surface. The bacterial PspC protein binds Factor H via short consensus repeats (SCR) 8–11 and SCR19–20. In this study, we define how bacterially bound Factor H promotes pneumococcal adherence to and uptake by epithelial cells or human polymorphonuclear leukocytes (PMNs) via a two-step process. First, pneumococcal adherence to epithelial cells was significantly reduced by heparin and dermatan sulfate. However, none of the glycosaminoglycans affected binding of Factor H to pneumococci. Adherence of pneumococci to human epithelial cells was inhibited by monoclonal antibodies recognizing SCR19–20 of Factor H suggesting that the C-terminal glycosaminoglycan-binding region of Factor H mediates the contact between pneumococci and human cells. Blocking of the integrin CR3 receptor, i.e. CD11b and CD18, of PMNs or CR3-expressing epithelial cells reduced significantly the interaction of pneumococci with both cell types. Similarly, an additional CR3 ligand, Pra1, derived from Candida albicans, blocked the interaction of pneumococci with PMNs. Strikingly, Pra1 inhibited also pneumococcal uptake by lung epithelial cells but not adherence. In addition, invasion of Factor H-coated pneumococci required the dynamics of host-cell actin microfilaments and was affected by inhibitors of protein-tyrosine kinases and phosphatidylinositol 3-kinase. In conclusion, pneumococcal entry into host cells via Factor H is based on a two-step mechanism. The first and initial contact of Factor H-coated pneumococci is mediated by glycosaminoglycans expressed on the surface of human cells, and the second step, pneumococcal uptake, is integrin-mediated and depends on host signaling molecules such as phosphatidylinositol 3-kinase. PMID:20504767

  18. Kinetic characterization of ebselen, chelerythrine and apomorphine as glutaminase inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Ajit G.; Rojas, Camilo [Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205 (United States); Tanega, Cordelle; Shen, Min; Simeonov, Anton; Boxer, Matthew B.; Auld, Douglas S. [National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, MD 20850 (United States); Ferraris, Dana V. [Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205 (United States); Tsukamoto, Takashi [Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205 (United States); Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 (United States); Slusher, Barbara S., E-mail: bslusher@jhmi.edu [Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205 (United States); Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 (United States); Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21205 (United States)

    2013-08-23

    Highlights: •Ebselen, chelerythrine and apomorphine were identified as glutaminase inhibitors. •These had greater affinities and efficiency of inhibition than known prototypes. •Their previously reported biological activity could be due to glutaminase inhibition. -- Abstract: Glutaminase catalyzes the hydrolysis of glutamine to glutamate and plays a central role in the proliferation of neoplastic cells via glutaminolysis, as well as in the generation of excitotoxic glutamate in central nervous system disorders such as HIV-associated dementia (HAD) and multiple sclerosis. Both glutaminase siRNA and glutaminase inhibition have been shown to be effective in in vitro models of cancer and HAD, suggesting a potential role for small molecule glutaminase inhibitors. However, there are no potent, selective inhibitors of glutaminase currently available. The two prototypical glutaminase inhibitors, BPTES and DON, are either insoluble or non-specific. In a search for more drug-like glutaminase inhibitors, we conducted a screen of 1280 in vivo active drugs (Library of Pharmacologically Active Compounds (LOPAC{sup 1280})) and identified ebselen, chelerythrine and (R)-apomorphine. The newly identified inhibitors exhibited 10 to 1500-fold greater affinities than DON and BPTES and over 100-fold increased efficiency of inhibition. Although non-selective, it is noteworthy that the affinity of ebselen for glutaminase is more potent than any other activity yet described. It is possible that the previously reported biological activity seen with these compounds is due, in part, to glutaminase inhibition. Ebselen, chelerythrine and apomorphine complement the armamentarium of compounds to explore the role of glutaminase in disease.

  19. Susceptibility of KSHV-Infected PEL Cell Lines to the Human Complement System.

    Science.gov (United States)

    Yoo, Seung-Min; Jeon, Hyungtaek; Lee, Suhyuk; Lee, Myung-Shin

    2016-03-01

    Pleural effusion lymphoma (PEL) is a rare B-cell lymphoma that has a very poor prognosis with a median survival time of around 6 months. PEL is caused by Kaposi's sarcoma-associated herpesvirus, and is often co-infected with the Epstein Barr virus. The complement system is fundamental in the innate immune system against pathogen invasion and tumor development. In the present study, we investigated the activation of the complement system in PEL cells using human serum complements. Interestingly, two widely used PEL cell lines, BCP-1 and BCBL-1, showed different susceptibility to the complement system, which may be due to CD46 expression on their cell membranes. Complement activation did not induce apoptosis but supported cell survival considerably. Our results demonstrated the susceptibility of PEL to the complement system and its underlying mechanisms, which would provide insight into understanding the pathogenesis of PEL.

  20. The complement system and its role in the pathogenesis of periodontitis: current concepts.

    Science.gov (United States)

    Damgaard, C; Holmstrup, P; Van Dyke, T E; Nielsen, C H

    2015-06-01

    Periodontitis is a highly prevalent inflammatory disease in tooth supporting tissues, induced by bacteria growing in a biofilm on tooth surfaces. Components of the complement system are present in the periodontal tissue and the system is activated in periodontitis. Continuous complement activation and modulation by bacteria within the biofilm in periodontal pockets, however, may enhance local tissue destruction, providing the biofilm with both essential nutrients and space to grow. A more profound understanding of the mechanisms involved in complement-derived tissue degradation may facilitate the development of new treatment concepts for periodontitis. Further studies on the role of complement in periodontitis pathogenesis may also contribute to the understanding of why some individuals fail to resolve periodontitis. Here, we review evidence that links complement to the pathogenesis of periodontitis with an emphasis on interaction of complement with bacteria from periodontitis-associated biofilm. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Complement-mediated enhancement of HIV-1 infection in peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Nielsen, S D; Sørensen, A M; Schønning, Kristian

    1997-01-01

    We investigated if complement-mediated enhancement of HIV infection occurs in peripheral blood mononuclear cells (PBMC). In 7 experiments, we evaluated the effect of human complement on HIVIIIB infection in vitro. We measured HIV antigen production on day 4 and found that pre-incubation of HIV...... with complement led to enhanced production of antigen with a median enhancement of 2.5-fold (range 1.1-6.8). This complement-mediated increase in antigen production was statistically significant (p tested in CD4 cells enriched from PBMC, and CD4...... cells persistently gave higher levels of infection enhancement than PBMC. Thus, CD4 cells appear to be sufficient for complement-mediated enhancement of HIV infection to occur. In addition, we tested if it was possible to detect complement-mediated enhancement of primary HIV isolates in PBMC. We tested...

  2. 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.

  3. Comprehensive and comparative transcription analyses of the complement pathway in rainbow trout.

    Science.gov (United States)

    Köbis, Judith M; Rebl, Alexander; Kühn, Carsten; Korytář, Tomáš; Köllner, Bernd; Goldammer, Tom

    2015-01-01

    The complement system is one of the most ancient and most essential innate immune cascades throughout the animal kingdom. Survival of aquatic animals, such as rainbow trout, depends on this early inducible, efficient immune cascade. Despite increasing research on genes coding for complement components in bony fish, some complement-related genes are still unknown in salmonid fish. In the present study, we characterize the genes encoding complement factor D (CFD), CD93 molecule (CD93), and C-type lectin domain family 4, member M (CLEC4M) from rainbow trout (Oncorhynchus mykiss). Subsequently, we performed comprehensive and comparative expression analyses of 36 complement genes including CFD, CD93, and CLEC4M and further putative complement-associated genes to obtain general information about the functional gene interaction within the complement pathway in fish. These quantification analyses were conducted in liver, spleen and gills of healthy fish of two rainbow trout strains, selected for survival (strain BORN) and growth (Import strain), respectively. The present expression study clearly confirms for rainbow trout that liver represents the primary site of complement expression. Spleen and gills also express most complement genes, although the mean transcript levels were generally lower than in liver. The transcription data suggest a contribution of spleen and gills to complement activity. The comparison of the two rainbow trout strains revealed a generally similar complement gene expression. However, a significantly lower expression of numerous genes especially in spleen seems characteristic for the BORN strain. This suggests a strain-specific complement pathway regulation under the selected rearing conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Lack of hidden complement fixing IgM rheumatoid factor in adult seronegative rheumatoid arthritis.

    OpenAIRE

    Robbins, D L; Moore, T L

    1980-01-01

    IgM rheumatoid factors capable of complement fixation and activation are commonly present in the sera of adults with rheumatoid arthritis. Hidden complement fixing IgM rheumatoid factor has been demonstrated in the majority of patients with juvenile RA and hidden agglutinating IgM rheumatoid factors have been demonstrated in the serum of adults with seronegative rheumatoid arthritis. We studied 27 adults with seronegative rheumatoid arthritis and were unable to demonstrate hidden complement f...

  5. Activation of complement factor B contributes to murine and human myocardial ischemia/reperfusion injury

    OpenAIRE

    Nicholas Chun; Haddadin, Ala S.; Junying Liu; Yunfang Hou; Wong, Karen A.; Daniel Lee; Rushbrook, Julie I.; Karan Gulaya; Roberta Hines; Tamika Hollis; Beatriz Nistal Nuno; Mangi, Abeel A.; Sabet Hashim; Marcela Pekna; Amy Catalfamo

    2017-01-01

    The pathophysiology of myocardial injury that results from cardiac ischemia and reperfusion (I/R) is incompletely understood. Experimental evidence from murine models indicates that innate immune mechanisms including complement activation via the classical and lectin pathways are crucial. Whether factor B (fB), a component of the alternative complement pathway required for amplification of complement cascade activation, participates in the pathophysiology of myocardial I/R injury has not been...

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

    DEFF Research Database (Denmark)

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

    2007-01-01

    The complement system is an important part of the innate immune system, mediating several major effector functions and modulating adaptive immune responses. Three complement activation pathways exist: the classical pathway (CP), the alternative pathway (AP), and the lectin pathway (LP). The LP...... 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....

  7. Functional Characterization of APOBEC-1 Complementation Factor Phosphorylation Sites

    Science.gov (United States)

    Lehmann, David M.; Galloway, Chad A.; MacElrevey, Celeste; Sowden, Mark P.; Wedekind, Joseph E.; Smith, Harold C.

    2007-01-01

    ApoB mRNA editing involves site-specific deamination of cytidine 6666 producing an in-frame translation stop codon. Editing minimally requires APOBEC-1 and APOBEC-1 complementation factor (ACF). Metabolic stimulation of apoB mRNA editing in hepatocytes is associated with serine phosphorylation of ACF localized to editing competent, nuclear 27S editosomes. We demonstrate that activation of protein kinase C (PKC) stimulated editing and enhanced ACF phosphorylation in rat primary hepatocytes. Conversely, activation of protein kinase A (PKA) had no effect on editing. Recombinant PKC efficiently phosphorylated purified ACF64 protein in vitro, whereas PKA did not. Mutagenesis of predicted PKC phosphorylation sites S154 and S368 to alanine inhibited ethanol-stimulated induction of editing suggesting that these sites function in the metabolic regulation of editing. Consistent with this interpretation, substitution of S154 and S368 with aspartic acid stimulated editing to levels comparable to ethanol treatment in control McArdle RH7777 cells. These data suggest that phosphorylation of ACF by PKC may be a key regulatory mechanism of apoB mRNA editing in rat hepatocytes. PMID:17229474

  8. Magnetic bead based assays for complement component C5.

    Science.gov (United States)

    DiScipio, Richard G; Schraufstatter, Ingrid U

    2017-11-01

    Two novel magnetic agarose bead based assays have been developed to measure complement component C5 interaction with C3b and the Factor I Modules (FIMs) of C7. One innovation was to couple C3b onto the magnetic agarose bead using the alternative pathway C3 convertase, which resulted in a linkage of the ligand by a covalent ester bond. A second innovation was to employ nickel ion charged N,N,N'-tris(carboxymethyl)ethylene-diamine-magnetic agarose to capture recombinantly prepared C7 FIMs that were expressed with an oligo-histidine linker followed by an acidic domain that provided a spacer enabling the C7 modules exposure to C5. Detection was brought about by peroxidase coupled to C5. Both assays exhibited adequate statistics suitable for screening. As examples of the utility of these new methods, we chose to examine influence of natural products on C5 interaction. Fucoidan and β-glucans were observed to inhibit C3b-C5 interaction, and dextran sulfate was similarly active; however, rosmarinic acid had no measurable effect. In contrast only β-glucans from two species of macrofungi were able to interfere with interaction of C5 with the FIMs of C7. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Targeting Complement in Treatment of Intestinal Ischemia/Reperfusion-Induced Injury

    National Research Council Canada - National Science Library

    Fleming, Sherry D; Kiang, Juliann G; Tsokos, George C

    2004-01-01

    .... Understanding the role of complement and its natural regulatory molecules will enable the development of therapeutic interventions to prevent excessive damage during mesenteric ischemia/reperfusion (IR...

  10. Tuning complement activation and pathway through controlled molecular architecture of dextran chains in nanoparticle corona.

    Science.gov (United States)

    Coty, Jean-Baptiste; Eleamen Oliveira, Elquio; Vauthier, Christine

    2017-11-05

    The understanding of complement activation by nanomaterials is a key to a rational design of safe and efficient nanomedicines. This work proposed a systematic study investigating how molecular design of nanoparticle coronas made of dextran impacts on mechanisms that trigger complement activation. The nanoparticles used for this work consisted of dextran-coated poly(isobutylcyanoacrylate) (PIBCA) nanoparticles have already been thoroughly characterized. Their different capacity to trigger complement activation established on the cleavage of the protein C3 was also already described making these nanoparticles good models to investigate the relation between the molecular feature of their corona and the mechanism by which they triggered complement activation. Results of this new study show that complement activation pathways can be selected by distinct architectures formed by dextran chains composing the nanoparticle corona. Assumptions that explain the relation between complement activation mechanisms triggered by the nanoparticles and the nanoparticle corona molecular feature were proposed. These results are of interest to better understand how the design of dextran-coated nanomaterials will impact interactions with the complement system. It can open perspectives with regard to the selection of a preferential complement activation pathway or prevent the nanoparticles to activate the complement system, based on a rational choice of the corona configuration. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. The good and evil of complement activation in HIV-1 infection

    OpenAIRE

    Yu, Qigui; Yu, Richard; Qin, Xuebin

    2010-01-01

    The complement system, a key component of innate immunity, is a first-line defender against foreign pathogens such as HIV-1. The role of the complement system in HIV-1 pathogenesis appears to be multifaceted. Although the complement system plays critical roles in clearing and neutralizing HIV-1 virions, it also represents a critical factor for the spread and maintenance of the virus in the infected host. In addition, complement regulators such as human CD59 present in the envelope of HIV-1 pr...

  12. In vivo-generated thrombin and plasmin do not activate the complement system in baboons.

    Science.gov (United States)

    Keshari, Ravi S; Silasi, Robert; Lupu, Cristina; Taylor, Fletcher B; Lupu, Florea

    2017-12-14

    Sepsis concurrently activates both coagulation and complement systems. Although complement activation by bacteria is well documented, work in mice and in vitro suggests that coagulation proteases can directly cleave complement proteins. We aimed to determine whether generation of coagulation proteases in vivo can activate the complement cascade in 2 highly coagulopathic models. We compared temporal changes in activation biomarkers of coagulation (thrombin-antithrombin [TAT]), fibrinolysis (plasmin-antiplasmin [PAP]), and complement (C3b, C5a, C5b-9) in baboons infused with factor Xa (FXa) and phospholipids (FXa/phosphatidylcholine-phosphatidylserine [PCPS]) vs LD100 Escherichia coli We found that, albeit with different timing, both FXa/PCPS and E coli infusion led to robust thrombin and plasmin generation. Conversely, only E coli challenge activated the complement system, reaching a maximum at 2 hours postchallenge during the peaks of lipopolysaccharide and bacteremia but not of TAT and PAP. Despite inducing a strong burst of thrombin and plasmin, FXa/PCPS infusion did not produce measurable levels of complement activation in vivo. Similarly, ex vivo incubation of baboon serum with thrombin, plasmin, or FXa did not show noticeable complement cleavage unless supraphysiologic amounts of enzymes were used. Our results suggest that in vivo-generated thrombin and plasmin do not directly activate the complement in nonhuman primates. © 2017 by The American Society of Hematology.

  13. Dynamic control of the complement system by modulated expression of regulatory proteins.

    Science.gov (United States)

    Thurman, Joshua M; Renner, Brandon

    2011-01-01

    The complement system serves many biological functions, including the eradication of invasive pathogens and the removal of damaged cells and immune-complexes. Uncontrolled complement activation causes injury to host cells, however, so adequate regulation of the system is essential. Control of the complement system is maintained by a group of cell surface and circulating proteins referred to as complement regulatory proteins. The expression of the cell surface complement regulatory proteins varies from tissue to tissue. Furthermore, specific cell types can upregulate or downregulate the expression of these proteins in response to a variety of signals or insults. Altered regulation of the complement regulatory proteins can have important effects on local complement activation. In some circumstances this can be beneficial, such as in the setting of certain infections. In other circumstances, however, this can be a cause of complement-mediated injury of the tissue. A full understanding of the mechanisms by which the complement system is modulated at the local level can have important implications for how we diagnose and treat a wide range of inflammatory diseases.

  14. Regulation of complement and modulation of its activity in monoclonal antibody therapy of cancer

    Science.gov (United States)

    Meyer, Saskia; Leusen, Jeanette HW; Boross, Peter

    2014-01-01

    The complement system is a powerful tool of the innate immune system to eradicate pathogens. Both in vitro and in vivo evidence indicates that therapeutic anti-tumor monoclonal antibodies (mAbs) can activate the complement system by the classical pathway. However, the contribution of complement to the efficacy of mAbs is still debated, mainly due to the lack of convincing data in patients. A beneficial role for complement during mAb therapy is supported by the fact that cancer cells often upregulate complement-regulatory proteins (CRPs). Polymorphisms in various CRPs were previously associated with complement-mediated disorders. In this review the role of complement in anti-tumor mAb therapy will be discussed with special emphasis on strategies aiming at modifying complement activity. In the future, clinical efficacy of mAbs with enhanced effector functions together with comprehensive analysis of polymorphisms in CRPs in mAb-treated patients will further clarify the role of complement in mAb therapy. PMID:25517299

  15. 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......, formation of the C3 proconvertase C4b2, followed by cleavage of complement component C2 within C4b2 resulting in the C3 convertase C4b2a. Here we describe the solution structures of the two central complexes of the pathways, C3 proconvertase and C3 convertase, as well as the unbound zymogen C2 obtained...... to the crystal structure of the AP C3 convertase C3bBb which is in accordance with their identical functions in cleaving the complement proteins C3 and C5....

  16. The Spanish Complementizer System: Consequences for the Syntax of Dislocations and Subjects, Locality of Movement, and Clausal Structure

    Science.gov (United States)

    Villa-Garcia, Julio

    2012-01-01

    This dissertation investigates the syntax of Spanish complementizers, with special attention to double-complementizer constructions and non-high "que" "that" complementizers. The goal is to explore the consequences of the behavior and distribution of such complementizers for the mapping of the Spanish left periphery, the…

  17. 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 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.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.AP components are assembled and activated on EC-secreted/anchored ULVWF multimeric strings. Our findings provide one possible molecular mechanism for clinical

  18. 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.

  19. [Cytoplasmic kinase inhibitors].

    Science.gov (United States)

    Mano, Hiroyuki

    2010-10-01

    Protein kinases play essential roles in the regulation of cell proliferation. Point mutations or/and fusions of protein kinases are frequently identified in human cancers, and targeting such activated kinases provides us with a chance to eradicate tumor cells. This was first proved by imatinib mesylate that inhibits ABL tyrosine kinase and, thereby, efficiently kills malignant cells in chronic myeloid leukemia. In addition, other clinical trials are ongoing for kinase inhibitors against EML4--ALK in lung cancer, JAK2 in myeloproliferative disorders and BRAF in malignant melanoma. Early reports indeed reveal that such targeting compounds are promising drugs for human cancers with activated kinases.

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

    Science.gov (United States)

    Kenedy, Melisha R.; Akins, Darrin R.

    2011-01-01

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

  1. Proteomics of inflammatory and oxidative stress response in cows with subclinical and clinical mastitis.

    Science.gov (United States)

    Turk, Romana; Piras, Cristian; Kovačić, Mislav; Samardžija, Marko; Ahmed, Hany; De Canio, Michele; Urbani, Andrea; Meštrić, Zlata Flegar; Soggiu, Alessio; Bonizzi, Luigi; Roncada, Paola

    2012-07-19

    Cow serum proteome was evaluated by three different complementary approaches in the control group, subclinical and clinical mastitis in order to possibly find differential protein expression useful for a better understanding of the pathophysiology of mastitis as well as for an early diagnosis of the disease. The systemic inflammatory and oxidative stress response in cows with subclinical and clinical mastitis were observed. The collected evidence shows a differential protein expression of serpin A3-1, vitronectin-like protein and complement factor H in subclinical mastitis in comparison with the control. It was also found a differential protein expression of inter-alpha-trypsin inhibitor heavy chain H4, serpin A3-1, C4b-binding protein alpha chain, haptoglobin and apolipoprotein A-I in clinical mastitis compared to the control. Among the inflammatory proteins up-regulated in clinical mastitis, vitronectin is over-expressed in both subclinical and clinical mastitis indicating a strong bacterial infection. This suggests vitronectin as an important mediator in the pathogenesis of the onset of mastitis as well as a valuable marker for diagnosis of the subclinical form of the disease. Obtained data could be useful for the detection of mastitis during the subclinical phase and for a better comprehension of the pathophysiological mechanisms involved in the onset of the disease. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Vesiculovirus Neutralization by Natural IgM and Complement

    Science.gov (United States)

    Tesfay, Mulu Z.; Ammayappan, Arun; Federspiel, Mark J.; Barber, Glen N.; Stojdl, David; Peng, Kah-Whye

    2014-01-01

    ABSTRACT Because of its very low human seroprevalence, vesicular stomatitis virus (VSV) has promise as a systemic oncolytic agent for human cancer therapy. However, as demonstrated in this report, the VSV infectious titer drops by 4 log units during the first hour of exposure to nonimmune human serum. This neutralization occurs relatively slowly and is mediated by the concerted actions of natural IgM and complement. Maraba virus, whose G protein is about 80% homologous to that of VSV, is relatively resistant to the neutralizing activity of nonimmune human serum. We therefore constructed and rescued a recombinant VSV whose G gene was replaced by the corresponding gene from Maraba virus. Comparison of the parental VSV and VSV with Maraba G substituted revealed nearly identical host range properties and replication kinetics on a panel of tumor cell lines. Moreover, in contrast to the parental VSV, the VSV with Maraba G substituted was resistant to nonimmune human serum. Overall, our data suggest that VSV with Maraba G substituted should be further investigated as a candidate for human systemic oncolytic virotherapy applications. IMPORTANCE Oncolytic virotherapy is a promising approach for the treatment of disseminated cancers, but antibody neutralization of circulating oncolytic virus particles remains a formidable barrier. In this work, we developed a pseudotyped vesicular stomatitis virus (VSV) with a glycoprotein of Maraba virus, a closely related but serologically distinct member of the family Rhabdoviridae, which demonstrated greatly diminished susceptibility to both nonimmune and VSV-immune serum neutralization. VSV with Maraba G substituted or lentiviral vectors should therefore be further investigated as candidates for human systemic oncolytic virotherapy and gene therapy applications. PMID:24648451

  3. Atypical haemolytic uraemic syndrome associated with a hybrid complement gene.

    Directory of Open Access Journals (Sweden)

    Julian P Venables

    2006-10-01

    Full Text Available BACKGROUND: Sequence analysis of the regulators of complement activation (RCA cluster of genes at chromosome position 1q32 shows evidence of several large genomic duplications. These duplications have resulted in a high degree of sequence identity between the gene for factor H (CFH and the genes for the five factor H-related proteins (CFHL1-5; aliases CFHR1-5. CFH mutations have been described in association with atypical haemolytic uraemic syndrome (aHUS. The majority of the mutations are missense changes that cluster in the C-terminal region and impair the ability of factor H to regulate surface-bound C3b. Some have arisen as a result of gene conversion between CFH and CFHL1. In this study we tested the hypothesis that nonallelic homologous recombination between low-copy repeats in the RCA cluster could result in the formation of a hybrid CFH/CFHL1 gene that predisposes to the development of aHUS. METHODS AND FINDINGS: In a family with many cases of aHUS that segregate with the RCA cluster we used cDNA analysis, gene sequencing, and Southern blotting to show that affected individuals carry a heterozygous CFH/CFHL1 hybrid gene in which exons 1-21 are derived from CFH and exons 22/23 from CFHL1. This hybrid encodes a protein product identical to a functionally significant CFH mutant (c.3572C>T, S1191L and c.3590T>C, V1197A that has been previously described in association with aHUS. CONCLUSIONS: CFH mutation screening is recommended in all aHUS patients prior to renal transplantation because of the high risk of disease recurrence post-transplant in those known to have a CFH mutation. Because of our finding it will be necessary to implement additional screening strategies that will detect a hybrid CFH/CFHL1 gene.

  4. Alcohol and cannabis use among college students: Substitutes or complements?

    Science.gov (United States)

    O'Hara, Ross E; Armeli, Stephen; Tennen, Howard

    2016-07-01

    Economists debate whether changes in availability of alcohol or cannabis are positively or negatively related to changes in use of the other substance. Implicit in these arguments are two competing, individual-level hypotheses-that people use alcohol and cannabis either as complements or substitutes for one another. This is the first study to test these hypotheses using micro-longitudinal data on individuals' alcohol and cannabis use on a given evening. United States college students who use alcohol and cannabis (n=876) were selected from a larger sample who participated in a 30-day online daily diary study. At baseline, students reported their proclivity to use alcohol/drugs to cope with stress. Each day students reported their level of alcohol use from the prior evening as well as whether they had used cannabis. Evening levels of alcohol use and mean levels of alcohol use positively predicted the likelihood of evening cannabis use, results indicative of complementary use. This relation, however, was moderated by coping style, such that students who were more likely to use alcohol/drugs to cope were less likely to use cannabis as their evening or mean alcohol use levels increased, results indicative of substitution. Substance-using college students showed evidence for complementary alcohol and cannabis use at both the within- and between-person levels. Students with a proclivity toward using alcohol/drugs to cope, however, showed evidence of substitution. These findings suggest that studies based on economic theories of substance use should take into account individual differences in substance use motives. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Double blockade of CD14 and complement C5 abolishes the cytokine storm and improves morbidity and survival in polymicrobial sepsis in mice.

    Science.gov (United States)

    Huber-Lang, Markus; Barratt-Due, Andreas; Pischke, Søren E; Sandanger, Øystein; Nilsson, Per H; Nunn, Miles A; Denk, Stephanie; Gaus, Wilhelm; Espevik, Terje; Mollnes, Tom E

    2014-06-01

    Sepsis and septic shock, caused by an excessive systemic host-inflammatory response, are associated with high morbidity and mortality. The complement system and TLRs provide important pattern recognition receptors initiating the cytokine storm by extensive cross-talk. We hypothesized that double blockade of complement C5 and the TLR coreceptor CD14 could improve survival of experimental polymicrobial sepsis. Mice undergoing cecal ligation and puncture (CLP)-induced sepsis were treated with neutralizing anti-CD14 Ab biG 53, complement C5 inhibitor coversin (Ornithodoros moubata C inhibitor), or a combination thereof. The inflammatory study (24-h observation) revealed statistically significant increases in 22 of 24 measured plasma biomarkers in the untreated CLP group, comprising 14 pro- and anti-inflammatory cytokines and 8 chemokines, growth factors, and granulocyte activation markers. Single CD14 or C5 blockade significantly inhibited 20 and 19 of the 22 biomarkers, respectively. Combined CD14 and C5 inhibition significantly reduced all 22 biomarkers (mean reduction 85%; range 54-95%) compared with the untreated CLP group. Double blockade was more potent than single treatment and was required to significantly inhibit IL-6 and CXCL1. Combined inhibition significantly reduced morbidity (motility and eyelid movement) and mortality measured over 10 d. In the positive control CLP group, median survival was 36 h (range 24-48 h). Combined treatment increased median survival to 96 h (range 24-240 h) (p = 0.001), whereas survival in the single-treatment groups was not significantly increased (median and range for anti-CD14 and anti-C5 treatment were 36 h [24-48 h] and 48 h [24-96 h]). Combined with standard intervention therapy, specific blockade of CD14 and C5 might represent a promising new therapeutic strategy for treatment of polymicrobial sepsis. Copyright © 2014 by The American Association of Immunologists, Inc.

  6. 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

  7. Von Neumann algebras as complemented subspaces of B(H)

    DEFF Research Database (Denmark)

    Christensen, Erik; Wang, Liguang

    2014-01-01

    Let M be a von Neumann algebra of type II1 which is also a complemented subspace of B( H). We establish an algebraic criterion, which ensures that M is an injective von Neumann algebra. As a corollary we show that if M is a complemented factor of type II1 on a Hilbert space H, then M is injective...

  8. Complement activity in the cord blood of term neonates with the ...

    African Journals Online (AJOL)

    Cord blood samples from 11 term neonates whose placentas showed histological changes typical of the amniotic fluid infection syndrome were analysed in order to determine haemolytic activity of the classic and alternative complement pathways and serum levels of complement proteins and immunoglobulins. Although the ...

  9. Human genetic deficiencies reveal the roles of complement in the inflammatory network: lessons from nature

    DEFF Research Database (Denmark)

    Lappegård, Knut Tore; Christiansen, Dorte; Pharo, Anne

    2009-01-01

    Complement component C5 is crucial for experimental animal inflammatory tissue damage; however, its involvement in human inflammation is incompletely understood. The responses to gram-negative bacteria were here studied taking advantage of human genetic complement-deficiencies--nature's own knock...

  10. Plasma complement biomarkers distinguish multiple sclerosis and neuromyelitis optica spectrum disorder.

    Science.gov (United States)

    Hakobyan, Svetlana; Luppe, Sebastian; Evans, David Rs; Harding, Katharine; Loveless, Samantha; Robertson, Neil P; Morgan, B Paul

    2017-06-01

    Multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) are autoimmune inflammatory demyelinating diseases of the central nervous system. Although distinguished by clinicoradiological and demographic features, early manifestations can be similar complicating management. Antibodies against aquaporin-4 support the diagnosis of NMOSD but are negative in some patients. Therefore, there is unmet need for biomarkers that enable early diagnosis and disease-specific intervention. We investigated whether plasma complement proteins are altered in MS and NMOSD and provide biomarkers that distinguish these diseases. Plasma from 54 NMOSD, 40 MS and 69 control donors was tested in multiplex assays measuring complement activation products and proteins. Using logistic regression, we tested whether combinations of complement analytes distinguished NMOSD from controls and MS. All activation products were elevated in NMOSD compared to either control or MS. Four complement proteins (C1inh, C1s, C5 and FH) were higher in NMOSD compared to MS or controls. A model comprising C1inh and terminal complement complex (TCC) distinguished NMOSD from MS (area under the curve (AUC): 0.98), while C1inh and C5 distinguished NMOSD from controls (AUC: 0.94). NMOSD is distinguished from MS by plasma complement biomarkers. Selected complement analytes enable differential diagnosis. Findings support trials of anti-complement therapies in NMOSD.

  11. 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

  12. Pseudomonas aeruginosa alkaline protease blocks complement activation via the classical and lectin pathways.

    Science.gov (United States)

    Laarman, Alexander J; Bardoel, Bart W; Ruyken, Maartje; Fernie, Job; Milder, Fin J; van Strijp, Jos A G; Rooijakkers, Suzan H M

    2012-01-01

    The complement system rapidly detects and kills Gram-negative bacteria and supports bacterial killing by phagocytes. However, bacterial pathogens exploit several strategies to evade detection by the complement system. The alkaline protease (AprA) of Pseudomonas aeruginosa has been associated with bacterial virulence and is known to interfere with complement-mediated lysis of erythrocytes, but its exact role in bacterial complement escape is unknown. In this study, we analyzed how AprA interferes with complement activation and whether it could block complement-dependent neutrophil functions. We found that AprA potently blocked phagocytosis and killing of Pseudomonas by human neutrophils. Furthermore, AprA inhibited opsonization of bacteria with C3b and the formation of the chemotactic agent C5a. AprA specifically blocked C3b deposition via the classical and lectin pathways, whereas the alternative pathway was not affected. Serum degradation assays revealed that AprA degrades both human C1s and C2. However, repletion assays demonstrated that the mechanism of action for complement inhibition is cleavage of C2. In summary, we showed that P. aeruginosa AprA interferes with classical and lectin pathway-mediated complement activation via cleavage of C2.

  13. Complement deficiencies limit CD20 monoclonal antibody treatment efficacy in CLL.

    Science.gov (United States)

    Middleton, O; Cosimo, E; Dobbin, E; McCaig, A M; Clarke, C; Brant, A M; Leach, M T; Michie, A M; Wheadon, H

    2015-01-01

    Monoclonal antibodies (MAbs) form a central part of chronic lymphocytic leukaemia (CLL) treatment. We therefore evaluated whether complement defects in CLL patients reduced the induction of complement-dependent cytotoxicity (CDC) by using anti-CD20 MAbs rituximab (RTX) and ofatumumab (OFA). Ofatumumab elicited higher CDC levels than RTX in all CLL samples examined, particularly in poor prognosis cohorts (11q- and 17p-). Serum sample analyses revealed that 38.1% of patients were deficient in one or more complement components, correlating with reduced CDC responses. Although a proportion of patients with deficient complement levels initially induced high levels of CDC, on secondary challenge CDC activity in sera was significantly reduced, compared with that in normal human serum (NHS; P<0.01; n=52). In addition, a high CLL cell number contributed to rapid complement exhaustion. Supplementing CLL serum with NHS or individual complement components, particularly C2, restored CDC on secondary challenge to NHS levels (P<0.0001; n=9). In vivo studies revealed that complement components were exhausted in CLL patient sera post RTX treatment, correlating with an inability to elicit CDC. Supplementing MAb treatment with fresh-frozen plasma may therefore maintain CDC levels in CLL patients with a complement deficiency or high white blood cell count. This study has important implications for CLL patients receiving anti-CD20 MAb therapy.

  14. 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...

  15. Complement plays a central role in Candida albicans-induced cytokine production by human PBMCs

    DEFF Research Database (Denmark)

    Cheng, Shih-Chin; Sprong, Tom; Joosten, Leo A B

    2012-01-01

    In experimental studies, the role of complement in antifungal host defense has been attributed to its opsonizing capability. In this study, we report that in humans an activated complement system mainly augments Candida albicans-induced host proinflammatory cytokine production via C5a-C5aR signal...

  16. Activated complement factor 3 is associated with liver fat and liver enzymes: the CODAM study

    NARCIS (Netherlands)

    Wlazlo, N.; Greevenbroek, van M.M.J.; Ferreira, I.; Jansen, E.H.J.M.; Feskens, E.J.M.; Kallen, van der C.J.H.; Schalkwijk, C.G.; Bravenboer, B.; Stehouwer, C.D.A.

    2013-01-01

    Background The complement system may be involved in the pathogenesis of alcoholic and nonalcoholic liver disease, although studies in humans are scarce. For this reason, we investigated whether circulating levels of activated complement factor 3 (C3a) were associated with hepatic steatosis and

  17. A standardized method for quantitating the complement-mediated immune complex solubilizing capacity of human serum

    DEFF Research Database (Denmark)

    Baatrup, G; Peterson, I; Svehag, S E

    1983-01-01

    A standardized radioassay for measuring the complement-mediated immune complex solubilizing capacity (CMSC) and the initial kinetics of the solubilization (IKS) reaction is described. The total complement (C)-mediated solubilizing capacity was determined after incubation of diluted serum and 125I...

  18. Changes of the complement system and rheological indicators after therapy with rheohemapheresis.

    Science.gov (United States)

    Blaha, M; Andrys, C; Langrova, H; Studnicka, J; Drsata, J; Lanska, M; Blaha, V; Zak, P

    2015-05-01

    In the last 10 years, many studies have been published on the role of the complement system in microcirculation disorders. However, as for the changes of complement components after rheohemapheresis, there is still a lack of detailed data in the literature. Complement changes may play an important role in pathogenesis of some microcirculation disorders, such as age-related macular degeneration and acute hearing loss. The objective of this study was to investigate the effect of rheohemapheresis on the basic complement pathways. 32 patients were treated with rheohemapheresis, including 16 patients (10 men and 6 women) for age-related macular degeneration (AMD), mean age 69.7 ± 6.06 years (range 62-87 years) and 16 patients (11 men and 5 women) aged 56.4 ± 11.5 (range 34-73 years) for acute hearing loss. Rheohemapheresis led to a significant drop of all three complement-activation pathways in both groups of patients. Moreover, complement factor H was also reduced. The observed reduction in all three basic complement activation pathways after rheohemapheresis could be clinically important. The search continues both to find substances which influence complement systems and to develop more effective new drugs that require less frequent administration and that provide improved intraocular therapy for AMD patients. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  19. Exploring the Innate Immune System: Using Complement-Medicated Cell Lysis in the Classroom

    Science.gov (United States)

    Fuller, Kevin G.

    2008-01-01

    The protein complement pathway comprises an important part of the innate immunity. The use of serum to demonstrate complement-mediated destruction across a series of bacterial dilutions allows an instructor to introduce a number of important biological concepts such as bacterial growth, activation cascades, and adaptive versus innate immunity.

  20. Complement-mediated tumour growth: implications for cancer nanotechnology and nanomedicines

    DEFF Research Database (Denmark)

    Moghimi, S. M.; Andresen, Thomas Lars

    2009-01-01

    The recent unexpected observation that complement activation helps turnout growth and progression has an important bearing on the future development of cancer nanomedicines for site-specific tumour targeting as these entities are capable of triggering complement. These issues are discussed and su...

  1. Complement-mediated enhancement of HIV-1 infection in peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Nielsen, S D; Sørensen, A M; Schønning, Kristian

    1997-01-01

    We investigated if complement-mediated enhancement of HIV infection occurs in peripheral blood mononuclear cells (PBMC). In 7 experiments, we evaluated the effect of human complement on HIVIIIB infection in vitro. We measured HIV antigen production on day 4 and found that pre-incubation of HIV wi...

  2. Complement activation by carbon nanotubes and its influence on the phagocytosis and cytokine response macrophages

    NARCIS (Netherlands)

    Pondman, K.M.; Sobik, M.T.; Nayak, A.; Tsolaki, A.G.; Jäkel, A.; Flahaut, E.; Hampel, S.; ten Haken, Bernard; Sim, R.B.; Kishore, U.D.

    2014-01-01

    Carbon nanotubes (CNTs) have promised a range of applications in biomedicine. Although influenced by the dispersants used, CNTs are recognized by the innate immune system, predominantly by the classical pathway of the complement system. Here, we confirm that complement activation by the CNT used

  3. The Manuscript That We Finished: Structural Separation Reduces the Cost of Complement Coercion

    Science.gov (United States)

    Lowder, Matthew W.; Gordon, Peter C.

    2015-01-01

    Two eye-tracking experiments examined the effects of sentence structure on the processing of complement coercion, in which an event-selecting verb combines with a complement that represents an entity (e.g., "began the memo"). Previous work has demonstrated that these expressions impose a processing cost, which has been attributed to the…

  4. Potential therapeutic benefit of C1-esterase inhibitor in neuromyelitis optica evaluated in vitro and in an experimental rat model.

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    Lukmanee Tradtrantip

    Full Text Available Neuromyelitis optica (NMO is an autoimmune demyelinating disease of the central nervous system in which binding of anti-aquaporin-4 (AQP4 autoantibodies (NMO-IgG to astrocytes causes complement-dependent cytotoxicity (CDC and inflammation resulting in oligodendrocyte and neuronal injury. There is compelling evidence for a central role of complement in NMO pathogenesis. Here, we evaluated the potential of C1-esterase inhibitor (C1-inh for complement-targeted therapy of NMO. C1-inh is an anti-inflammatory plasma protein with serine protease inhibition activity that has a broad range of biological activities on the contact (kallikrein, coagulation, fibrinolytic and complement systems. C1-inh is approved for therapy of hereditary angioedema (HAE and has been studied in a small safety trial in acute NMO relapses (NCT 01759602. In vitro assays of NMO-IgG-dependent CDC showed C1-inh inhibition of human and rat complement, but with predicted minimal complement inhibition activity at a dose of 2000 units in humans. Inhibition of complement by C1-inh was potentiated by ∼10-fold by polysulfated macromolecules including heparin and dextran sulfate. In rats, intravenous C1-inh at a dose 30-fold greater than that approved to treat HAE inhibited serum complement activity by <5%, even when supplemented with heparin. Also, high-dose C1-inh did not reduce pathology in a rat model of NMO produced by intracerebral injection of NMO-IgG. Therefore, although C1r and C1s are targets of C1-inh, our in vitro data with human serum and in vivo data in rats suggest that the complement inhibition activity of C1-inh in serum is too low to confer clinical benefit in NMO.

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

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    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.

  6. In vivo thrombus formation induced by complement activation on polymer surfaces.

    Science.gov (United States)

    Hayashi, K; Fukumura, H; Yamamoto, N

    1990-10-01

    To clarify involvement of complement activation in thrombus formation on polymer surfaces, in vitro complement activation was evaluated for polyethylene (PE) tubes radiation-graft copolymerized with acrylamide (AAm), acrylic acid (AC), 2-hydroxyethyl methacrylate (HEMA), N-vinylpyrrolidone (NVP), and vinyl alcohol (VOH), and compared to their in vivo antithrombogenicity and cell adherence in canine peripheral veins. The complement-activating surfaces (NVP and VOH) cause preferential adhesion of leukocytes and were more thrombogenic than the low complement-activating surfaces (AAm, PE, and HEMA). Infusion of naja haje cobra venom factor depressed leukocyte adhesion, followed by a marked decrease in thrombogenesis, for the strong classical-pathway-activating surface (NVP). Although estimation of in vitro activation for AC was inconclusive because of a large effect of adsorption, AC behaved like VOH in vivo. These results suggest that C5a(des Arg) mediated activation of leukocytes may play a role in thrombus formation by complement activation on polymer surfaces.

  7. The complement system and its role in the pathogenesis of periodontitis

    DEFF Research Database (Denmark)

    Damgaard, Christian; Holmstrup, Palle; Van Dyke, Thomas E.

    2015-01-01

    Periodontitis is a highly prevalent inflammatory disease in tooth supporting tissues, induced by bacteria growing in a biofilm on tooth surfaces. Components of the complement system are present in the periodontal tissue and the system is activated in periodontitis. Continuous complement activation...... and modulation by bacteria within the biofilm in periodontal pockets, however, may enhance local tissue destruction, providing the biofilm with both essential nutrients and space to grow. A more profound understanding of the mechanisms involved in complement-derived tissue degradation may facilitate...... the development of new treatment concepts for periodontitis. Further studies on the role of complement in periodontitis pathogenesis may also contribute to the understanding of why some individuals fail to resolve periodontitis. Here, we review evidence that links complement to the pathogenesis of periodontitis...

  8. Role of the complement cascade in cerebral aneurysm formation, growth, and rupture

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    Blake E. S. Taylor

    2015-06-01

    Full Text Available Rupture of intracranial aneurysms is the most common cause of nontraumatic subarachnoid hemorrhage, but the intricate neuroinflammatory processes which contribute to aneurysm pathophysiology are not well-understood. Mounting evidence has implicated the complement cascade in the progression of aneurysms from their formation to rupture. In this article, we identify and review studies that have sought to determine the role of the complement system in the aneurysm pathogenesis. The studies were generally conducted by immunhistological analyses on aneurysm tissue collected intraoperatively, and multiple components of the complement cascade and its modulators were identified in specific regions of the aneurysm wall. The results of the studies suggest that the complement cascade is locally upregulated and disinhibited in the perianeurysmal environment, and that it contributes to chronic as well as acute immunological damage to the aneurysm wall. In the future, understanding the mechanisms at work in complement-mediated damage is necessary to leading the development of novel therapies.

  9. Relationship between the complement system, risk factors and prediction models in age-related macular degeneration.

    Science.gov (United States)

    Bora, Nalini S; Matta, Bharati; Lyzogubov, Valeriy V; Bora, Puran S

    2015-02-01

    Studies performed over the past decade in humans and experimental animals have been a major source of information and improved our understanding of how dysregulation of the complement system contributes to age-related macular degeneration (AMD) pathology. Drusen, the hall-mark of dry-type AMD are reported to be the by-product of complement mediated inflammatory processes. In wet AMD, unregulated complement activation results in increased production of angiogenic growth factors leading to choroidal neovascularization both in humans and in animal models. In this review article we have linked the complement system with modifiable and non-modifiable AMD risk factors as well as with prediction models of AMD. Understanding the association between the complement system, risk factors and prediction models will help improve our understanding of AMD pathology and management of this disease. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. The complement system and toll-like receptors as integrated players in the pathophysiology of atherosclerosis

    DEFF Research Database (Denmark)

    Hovland, Anders; Jonasson, Lena; Garred, Peter

    2015-01-01

    of innate immunity. The complement system and toll-like receptors (TLRs), and the crosstalk between them, may be of particular interest both with respect to pathogenesis and as therapeutic targets in atherosclerosis. Animal studies indicate that inhibition of C3a and C5a reduces atherosclerosis. In humans...... modified LDL-cholesterol activate complement and TLRs leading to downstream inflammation, and histopathological studies indicate that the innate immune system is present in atherosclerotic lesions. Moreover, clinical studies have demonstrated that both complement and TLRs are upregulated in atherosclerotic...... diseases, although interventional trials have this far been disappointing. However, based on recent research showing an intimate interplay between complement and TLRs we propose a model in which combined inhibition of both complement and TLRs may represent a potent anti-inflammatory therapeutic approach...

  11. Methyl Jasmonate Induces Papain Inhibitor(s) in Tomato Leaves.

    Science.gov (United States)

    Bolter, C. J.

    1993-12-01

    Leaves of 18- to 24-d-old tomato (Lycopersicon esculentum) plants exposed to gaseous methyl jasmonate (MJ) for 24 h at 30[deg]C in continuous light contained high levels of soluble protein that inhibited papain. Chromatographic analysis demonstrated that the active protein had a molecular mass of 80 to 90 kD. Induction of papain inhibitor was directly related to the concentration of air-borne MJ up to a maximum of 0.1 [mu]L MJ per treatment and depended on the duration of exposure up to 18 h. Inhibitor activity in plants treated for less than 18 h increased with time after treatment. Levels remained constant for up to 4 d after treatment, after which time activity decreased. The youngest leaf, leaf 5, consistently lost activity at a faster rate than older, lower leaves. Inhibitor concentration in all leaves was reduced to minimum levels by 11 d after MJ treatment, but did not return to control levels. Treatment with MJ in the dark did induce inhibitor activity, but at a significantly lower rate. Polyclonal antibodies raised to purified potato tuber skin cysteine proteinase inhibitors (CPI) cross-reacted with the tomato inhibitor, suggesting that the tomato papain inhibitor and the potato CPI are closely related. No papain inhibitor activity was observed in extracts from wounded tomato leaves, nor was there any immunoreactivity with antibodies raised to potato tuber skin CPI.

  12. Complement Factor H 402H Variant and Reticular Macular Disease

    Science.gov (United States)

    Smith, R. Theodore; Merriam, Joanna E.; Sohrab, Mahsa A.; Pumariega, Nicole M.; Barile, Gaetano; Blonska, Anna M.; Haans, Raymond; Madigan, David; Allikmets, Rando

    2013-01-01

    Objective To determine the association of high-risk alleles in the complement factor H (CFH; Y402H, rs1061170) and age-related maculopathy susceptibility (ARMS2; A69S, rs10490924) genes with reticular macular disease (RMD), a major clinical subphenotype of age-related macular degeneration (AMD). Methods Using retinal images from the Columbia Macular Genetics Study, we identified 67 subject individuals with RMD. A comparison group of 64 subjects with AMD without RMD was matched by ethnicity, age, sex, and AMD clinical stage. Results In the RMD group, 53 of 67 subjects (79.1%) were female, the mean age was 83 years, and 47 of 67 (70.1%) had late AMD, with closely matched values in the non-RMD group. The frequencies of the CFH 402H allele were 39.6% in the RMD group (53 of 134 individuals) and 58.6% in the non-RMD group (75 of 128 individuals) (χ2=8.8; P=.003; odds ratio, 0.46 [95% confidence interval, 0.28–0.76]). The corresponding frequencies of the risk allele for ARMS2 were 44.0% (40 of 128 individuals) and 31.3% (40 of 128 individuals), respectively (χ2=4.0; P=.045; odds ratio, 1.73 [95% confidence interval, 1.04–2.90]). Homozygosity for 402Hwas particularly associated with the absence of RMD, occurring in 8 of 67 subjects (11.9%) with RMD vs 24 of 64 subjects (37.5%) without RMD(P χ.001). Retinal macular disease also was associated with hypertension among male patients. Conclusions The AMD-associated CFH 402H risk variant is significantly associated with the absence of RMD but enhanced risk for RMD is conferred by the ARMS2 69S AMD risk allele. These results are consistent with the hypothesis that 402H may confer a survival benefit against certain infections, some of which may cause RMD. Clinical Relevance Reticular macular disease may be genetically distinct from the rest of AMD. PMID:21825189

  13. Successful C1 inhibitor short-term prophylaxis during redo mitral valve replacement in a patient with hereditary angioedema

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    Coleman Suzanne

    2010-10-01

    Full Text Available Abstract Hereditary angioedema is characterized by sudden episodes of nonpitting edema that cause discomfort and pain. Typically the extremities, genitalia, trunk, gastrointestinal tract, face, and larynx are affected by attacks of swelling. Laryngeal swelling carries significant risk for asphyxiation. The disease results from mutations in the C1 esterase inhibitor gene that cause C1 esterase inhibitor deficiency. Attacks of hereditary angioedema result from contact, complement, and fibrinolytic plasma cascade activation, where C1 esterase inhibitor irreversibly binds substrates. Patients with hereditary angioedema cannot replenish C1 esterase inhibitor levels on pace with its binding. When C1 esterase inhibitor is depleted in these patients, vasoactive plasma cascade products cause swelling attacks. Trauma is a known trigger for hereditary angioedema attacks, and patients have been denied surgical procedures because of this risk. However, uncomplicated surgeries have been reported. Appropriate prophylaxis can reduce peri-operative morbidity in these patients, despite proteolytic cascade and complement activation during surgical trauma. We report a case of successful short-term prophylaxis with C1 esterase inhibitor in a 51-year-old man with hereditary angioedema who underwent redo mitral valve reconstructive surgery.

  14. Activity and activation of the complement system in patients being operated on for cancer of the colon

    DEFF Research Database (Denmark)

    Baatrup, G; Qvist, N; Junker, A

    1994-01-01

    OBJECTIVE: To find out if there was any local activation of complement in the vicinity of a colonic cancer, and any fluctuation in the function of the complement system during operation. DESIGN: Prospective study. SETTING: One university and two district hospitals in Denmark. SUBJECTS: 29 selected...... patients undergoing emergency and elective operations for colonic cancer. INTERVENTIONS: Measurements of systemic and local complement fixation capacity and complement activation in samples of serum or plasma taken before, during, and after operation. MAIN OUTCOME MEASURES: Changes in complement fixation...... capacity and complement activation during operation. RESULTS: Haemodilution during operation caused a significant reduction in the complement fixation capacity of serum and in the activation of the complement system as measured by generation of C3c. We were unable to confirm the presence of complement...

  15. 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. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Cleavage of kininogen and subsequent bradykinin release by the complement component: mannose-binding lectin-associated serine protease (MASP-1.

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    József Dobó

    Full Text Available Bradykinin (BK, generated from high-molecular-weight kininogen (HK is the major mediator of swelling attacks in hereditary angioedema (HAE, a disease associated with C1-inhibitor deficiency. Plasma kallikrein, activated by factor XIIa, is responsible for most of HK cleavage. However other proteases, which activate during episodes of angioedema, might also contribute to BK production. The lectin pathway of the complement system activates after infection and oxidative stress on endothelial cells generating active serine proteases: MASP-1 and MASP-2. Our aim was to study whether activated MASPs are able to digest HK to release BK. Initially we were trying to find potential new substrates of MASP-1 in human plasma by differential gel electrophoresis, and we identified kininogen cleavage products by this proteomic approach. As a control, MASP-2 was included in the study in addition to MASP-1 and kallikrein. The proteolytic cleavage of HK by MASPs was followed by SDS-PAGE, and BK release was detected by HPLC. We showed that MASP-1 was able to cleave HK resulting in BK production. MASP-2 could also cleave HK but could not release BK. The cleavage pattern of MASPs is similar but not strictly identical to that of kallikrein. The catalytic efficiency of HK cleavage by a recombinant version of MASP-1 and MASP-2 was about 4.0×10(2 and 2.7×10(2 M(-1 s(-1, respectively. C1-inhibitor, the major inhibitor of factor XIIa and kallikrein, also prevented the cleavage of HK by MASPs. In all, a new factor XII- and kallikrein-independent mechanism of bradykinin production by MASP-1 was demonstrated, which may contribute to the pro-inflammatory effect of the lectin pathway of complement and to the elevated bradykinin levels in HAE patients.

  17. Utilizing CMP-Sialic Acid Analogs to Unravel Neisseria gonorrhoeae Lipooligosaccharide-Mediated Complement Resistance and Design Novel Therapeutics.

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    Sunita Gulati

    2015-12-01

    Full Text Available Neisseria gonorrhoeae deploys a novel immune evasion strategy wherein the lacto-N-neotetraose (LNnT structure of lipooligosaccharide (LOS is capped by the bacterial sialyltransferase, using host cytidine-5'-monophosphate (CMP-activated forms of the nine-carbon nonulosonate (NulO sugar N-acetyl-neuraminic acid (Neu5Ac, a sialic acid (Sia abundant in humans. This allows evasion of complement-mediated killing by recruiting factor H (FH, an inhibitor of the alternative complement pathway, and by limiting classical pathway activation ("serum-resistance". We utilized CMP salts of six additional natural or synthetic NulOs, Neu5Gc, Neu5Gc8Me, Neu5Ac9Ac, Neu5Ac9Az, legionaminic acid (Leg5Ac7Ac and pseudaminic acid (Pse5Ac7Ac, to define structural requirements of Sia-mediated serum-resistance. While all NulOs except Pse5Ac7Ac were incorporated into the LNnT-LOS, only Neu5Gc incorporation yielded high-level serum-resistance and FH binding that was comparable to Neu5Ac, whereas Neu5Ac9Az and Leg5Ac7Ac incorporation left bacteria fully serum-sensitive and did not enhance FH binding. Neu5Ac9Ac and Neu5Gc8Me rendered bacteria resistant only to low serum concentrations. While serum-resistance mediated by Neu5Ac was associated with classical pathway inhibition (decreased IgG binding and C4 deposition, Leg5Ac7Ac and Neu5Ac9Az incorporation did not inhibit the classical pathway. Remarkably, CMP-Neu5Ac9Az and CMP-Leg5Ac7Ac each prevented serum-resistance despite a 100-fold molar excess of CMP-Neu5Ac in growth media. The concomitant presence of Leg5Ac7Ac and Neu5Ac on LOS resulted in uninhibited classical pathway activation. Surprisingly, despite near-maximal FH binding in this instance, the alternative pathway was not regulated and factor Bb remained associated with bacteria. Intravaginal administration of CMP-Leg5Ac7Ac to BALB/c mice infected with gonorrhea (including a multidrug-resistant isolate reduced clearance times and infection burden. Bacteria recovered

  18. Utilizing CMP-Sialic Acid Analogs to Unravel Neisseria gonorrhoeae Lipooligosaccharide-Mediated Complement Resistance and Design Novel Therapeutics.

    Science.gov (United States)

    Gulati, Sunita; Schoenhofen, Ian C; Whitfield, Dennis M; Cox, Andrew D; Li, Jianjun; St Michael, Frank; Vinogradov, Evgeny V; Stupak, Jacek; Zheng, Bo; Ohnishi, Makoto; Unemo, Magnus; Lewis, Lisa A; Taylor, Rachel E; Landig, Corinna S; Diaz, Sandra; Reed, George W; Varki, Ajit; Rice, Peter A; Ram, Sanjay

    2015-12-01

    Neisseria gonorrhoeae deploys a novel immune evasion strategy wherein the lacto-N-neotetraose (LNnT) structure of lipooligosaccharide (LOS) is capped by the bacterial sialyltransferase, using host cytidine-5'-monophosphate (CMP)-activated forms of the nine-carbon nonulosonate (NulO) sugar N-acetyl-neuraminic acid (Neu5Ac), a sialic acid (Sia) abundant in humans. This allows evasion of complement-mediated killing by recruiting factor H (FH), an inhibitor of the alternative complement pathway, and by limiting classical pathway activation ("serum-resistance"). We utilized CMP salts of six additional natural or synthetic NulOs, Neu5Gc, Neu5Gc8Me, Neu5Ac9Ac, Neu5Ac9Az, legionaminic acid (Leg5Ac7Ac) and pseudaminic acid (Pse5Ac7Ac), to define structural requirements of Sia-mediated serum-resistance. While all NulOs except Pse5Ac7Ac were incorporated into the LNnT-LOS, only Neu5Gc incorporation yielded high-level serum-resistance and FH binding that was comparable to Neu5Ac, whereas Neu5Ac9Az and Leg5Ac7Ac incorporation left bacteria fully serum-sensitive and did not enhance FH binding. Neu5Ac9Ac and Neu5Gc8Me rendered bacteria resistant only to low serum concentrations. While serum-resistance mediated by Neu5Ac was associated with classical pathway inhibition (decreased IgG binding and C4 deposition), Leg5Ac7Ac and Neu5Ac9Az incorporation did not inhibit the classical pathway. Remarkably, CMP-Neu5Ac9Az and CMP-Leg5Ac7Ac each prevented serum-resistance despite a 100-fold molar excess of CMP-Neu5Ac in growth media. The concomitant presence of Leg5Ac7Ac and Neu5Ac on LOS resulted in uninhibited classical pathway activation. Surprisingly, despite near-maximal FH binding in this instance, the alternative pathway was not regulated and factor Bb remained associated with bacteria. Intravaginal administration of CMP-Leg5Ac7Ac to BALB/c mice infected with gonorrhea (including a multidrug-resistant isolate) reduced clearance times and infection burden. Bacteria recovered from CMP

  19. Proteinase inhibitors in Brazilian leguminosae

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    C. A. M. Sampaio

    1991-01-01

    Full Text Available Serine proteinase inhitors, in the seeds of several Leguminosae from the Pantanal region (West Brazil, were studied using bovine trypsin, a digestive enzyme, Factor XIIa and human plasma Kallikrein, two blood clotting factors. The inhibitors were purified from Enterolobium contortisiliquum (Mr=23,000, Torresea cearensis (Mr = 13,000, Bauhinia pentandra (Mr = 20,000 and Bauhinia bauhinioides (Mr = 20,000. E. contortisiliquum inhibitor inactivates all three enzymes, whereas the T. cearensis inhibitor inactivates trypsin and Factor XSSa, but does nor affect plasma kallikrein; both Bauhinia inhibitors, on the other hand, inactivate trypsin and plasma kallikrein but only the Bpentandra inhibitor affects Factor XIIa. Ki values were calculated between 10 [raised to the power of] -7 and 10 [raised to the power of] -8 M.

  20. 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...

  1. FUNCTIONAL ACTIVITY OF COMPLEMENT CLASSIC WAY ACTIVATION COMPONENTS AND ART1CULAS DAMAGE IN RHEUMATOID ARTRITIS

    Directory of Open Access Journals (Sweden)

    D. L. Goryachev

    2000-01-01

    Full Text Available A relationship between X - ray joints changes and functional activity of classical pathway complement components in R4 was investigated. 31 patients with the moderate activity ofRA (ARA 1987 have been examined. Disease duration was 4,5lyear±3,84 (SD. X-ray stage was estimated by Steinbrocker (I-II-III-IV. II patients were in II stage, 8 in III stage, 12 in IV-stage. Concentration of C3 and C4 components have been evaluated by radial immunodiffuision, functional activity of complement components (Clq. C1-C5 - using a microhemolilical systems. High correlation values between functional activity C1-C4 complement components and X-ray stage of disease were obtained (Spearman correlation: 0,38complement components is associated with severe joints destruction. Correlation ofC3, C4 concentration was not significant. This fact can be resulting from the phenomenon that complement classical pathway take part in joints destruction in RA. The feature of relationship can be ascribed to both primary high FA of complement classical pathway in patients with se\\'ere joints destruction and local consumption of complement at early stage ofjoints destruction.

  2. Complement emerges as a masterful regulator of CNS homeostasis, neural synaptic plasticity and cognitive function.

    Science.gov (United States)

    Mastellos, Dimitrios C

    2014-11-01

    Growing evidence points to a previously elusive role of complement-modulated pathways in CNS development, neurogenesis and synaptic plasticity. Distinct complement effectors appear to play a multifaceted role in brain homeostasis by regulating synaptic pruning in the retinogeniculate system and sculpting functional neural circuits both in the developing and adult mammalian brain. A recent study by Perez-Alcazar et al. (2014) provides novel insights into this intricate interplay between complement and the dynamically regulated brain synaptic circuitry, by reporting that mice deficient in C3 exhibit enhanced hippocampus-dependent spatial learning and cognitive performance. This behavioral pattern is associated with an impact of C3 on the functional capacity of glutamatergic synapses, supporting a crucial role for complement in excitatory synapse elimination in the hippocampus. These findings add a fresh twist to this rapidly evolving research field, suggesting that discrete complement components may differentially modulate synaptic connectivity by wiring up with diverse neural effectors in different regions of the brain. The emerging role of complement in synaptogenesis and neural network plasticity opens new conceptual avenues for considering complement interception as a potential therapeutic modality for ameliorating progressive cognitive impairment in age-related, debilitating brain diseases with a prominent inflammatory signature. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Induction of contact sensitivity by cell-associated immunocomplexes requires activation of the early complement components.

    Science.gov (United States)

    Lio, D; Sireci, G; Gervasi, F; Dieli, F; Salerno, A

    1992-12-01

    Lymph node cells collected from CBA/J mice 4 days after painting the skin with picryl chloride behave like antigen presenting cells and induce contact sensitivity when injected into naive recipient mice. The immunizing capacity of these '4-day' cells is due to T cells which carry on their membrane hapten-IgM immunocomplexes. Incubation of the cells with complement from mouse strains that express high C4 serum levels (C4H), abolishes their immunizing capacity. This effect is related to the activation of the early components of the classical complement pathway, as supported by experiments using C3 and C4-depleted or C5 and C6-genetically deficient mouse sera. The detection of different amounts of C3b and C4b on the surface of 4-day T cells after incubation with C4L and C4H sera supports the possibility that membrane bound activated complement components could modify the immunizing capacity of these cells. Results herein reported suggest that membrane-bound C3b and C4b are not per se inhibitory but interfere with the residual complement activating capacity of 4-day T cells. The role of complement activation by 4-day T cells is pivotal as complement depletion of recipient mice by cobra venom factor (CVF) inhibits the immunizing capacity of untreated 4-day T cells, while 4-day T cells treated with complement in vitro and injected together with C4a anaphylatoxin are able to immunize recipient mice.

  4. Rapid induction of neutrophil-endothelial adhesion by endothelial complement fixation.

    Science.gov (United States)

    Marks, R M; Todd, R F; Ward, P A

    1989-05-25

    The adhesion of neutrophils to vascular endothelium is an early event in their recruitment into acute inflammatory lesions. In evaluating potential neutrophil-endothelial adhesive mechanisms in acute inflammation, important considerations are that adhesion in vivo may occur very rapidly following injury and that the specificity of the reaction resides in altered endothelium. That is, neutrophils adhere only to altered endothelium adjacent to an inflammatory focus, rather than at random as would be expected if activation of neutrophils were the initiator of adhesion. We have explored a possible bridging role for complement in causing early neutrophil-endothelial cell adhesion. The complement system is involved in inflammatory processes, is capable of rapid amplification, and endothelial complement fixation at sites of inflammation could generate an endothelium-restricted signal for neutrophil adhesion. We have now developed a model in which this can be investigated without complicating factors such as immunoglobulin deposition, by constructing a novel molecule, a hybrid of the endothelial binding lectin Ulex europaeus I and of the complement activator cobra venom factor. This molecule has the capacity to cause fixation of complement on human umbilical vein endothelial cells. We show that complement fixation is a potent and rapid stimulus for neutrophil adhesion. Neutrophil adhesion requires only endothelial deposition of C3, and is mediated through the type 3 complement receptor.

  5. Targeting the complement system for the management of retinal inflammatory and degenerative diseases.

    Science.gov (United States)

    Xu, Heping; Chen, Mei

    2016-09-15

    The retina, an immune privileged tissue, has specialized immune defense mechanisms against noxious insults that may exist in diseases such as age-related macular degeneration (AMD), diabetic retinopathy (DR), uveoretinitis and glaucoma. The defense system consists of retinal innate immune cells (including microglia, perivascular macrophages, and a small population of dendritic cells) and the complement system. Under normal aging conditions, retinal innate immune cells and the complement system undergo a low-grade activation (parainflammation) which is important for retinal homeostasis. In disease states such as AMD and DR, the parainflammatory response is dysregulated and develops into detrimental chronic inflammation. Complement activation in the retina is an important part of chronic inflammation and may contribute to retinal pathology in these disease states. Here, we review the evidence that supports the role of uncontrolled or dysregulated complement activation in various retinal degenerative and angiogenic conditions. We also discuss current strategies that are used to develop complement-based therapies for retinal diseases such as AMD. The potential benefits of complement inhibition in DR, uveoretinitis and glaucoma are also discussed, as well as the need for further research to better understand the mechanisms of complement-mediated retinal damage in these disease states. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  6. [Alternation of retinal complement system in a mouse model of lipopolysaccharide- induced uveitis].

    Science.gov (United States)

    Tao, Xueying; Zheng, Shijie; Lei, Bo

    2014-07-01

    To investigate the activation of the complement system in the retina in a mouse model of endotoxin-induced uveitis (EIU). Balb/c mice were randomly divided into control group and lipopolysaccharide (LPS)-induced EIU group. Twenty-four hours after modeling, the expressions of the major complement components of the classical pathway (CP), mannose-binding lectin (MBL) pathway, alternative pathway (AP), and terminal pathway in the retina were determined by quantitative RT-PCR. Western blotting was employed to examine the protein expressions of the key components of the complement system involved in the CP and AP pathways in the retina. s Normal mouse retina expressed a variety of complement components that were involved mainly in the CP and AP pathways. The expressions of the complement components involved in the CP and AP pathways were up-regulated in the retina of mice with EIU. Although MASP1 and MASP2 were detected in the retina in both the EIU and control groups, their expressions were weak and showed no significant difference between the two groups. The AP and CP but not the MBL pathways of the complement system are activated in the retina of mice with EIU, suggesting a role of the activated complement system in the pathological process of EIU.

  7. The Bordetella pertussis Bps Polysaccharide Enhances Lung Colonization by Conferring Protection from Complement-mediated Killing

    Science.gov (United States)

    Ganguly, Tridib; Johnson, John B.; Kock, Nancy D.; Parks, Griffith D.; Deora, Rajendar

    2014-01-01

    Summary Bordetella pertussis is a human-restricted Gram-negative bacterial pathogen that causes whooping cough or pertussis. Pertussis is the leading vaccine preventable disease that is resurging in the USA and other parts of the developed world. There is an incomplete understanding of the mechanisms by which B. pertussis evades killing and clearance by the complement system, a first line of host innate immune defense. The present study examined the role of the Bps polysaccharide to resist complement activity in vitro and in the mouse respiratory tract. The isogenic bps mutant strain containing a large non polar in-frame deletion of the bpsA-D locus was more sensitive to serum and complement mediated killing than the WT strain. As determined by western blotting, flow cytometry and electron microscopic studies, the heightened sensitivity of the mutant strain was due to enhanced deposition of complement proteins and the formation of membrane attack complex, the end product of complement activation. Bps was sufficient to confer complement resistance as evidenced by a Bps-expressing E. coli being protected by serum killing. Additionally, western blotting and flow cytometry assays revealed that Bps inhibited the deposition of complement proteins independent of other B. pertussis factors. The bps mutant strain colonized the lungs of complement-deficient mice at higher levels than that observed in C57Bl/6 mice. These results reveal a previously unknown interaction between Bps and the complement system in controlling B. pertussis colonization of the respiratory tract. These findings also make Bps a potential target for the prevention and therapy of whooping cough. PMID:24438122

  8. Quantitative Mass Spectrometry To Study Inflammatory Cartilage Degradation and Resulting Interactions with the Complement System.

    Science.gov (United States)

    Melin Fürst, Camilla; Åhrman, Emma; Bratteby, Klas; Waldemarson, Sofia; Malmström, Johan; Blom, Anna M

    2016-10-15

    Joint diseases are often characterized by inflammatory processes that result in pathological changes in joint tissues, including cartilage degradation and release of components into the synovial fluid. The complement system plays a central role in promoting the inflammation. Because several cartilage proteins are known to interact with complement, causing either activation or inhibition of the system, we aimed to investigate these interactions comprehensively. Bovine cartilage explants were cultured with IL-1α to induce cartilage degradation, followed by incubation with human serum. Label-free selected reaction monitoring mass spectrometry was used to specifically quantify complement proteins interacting with the cartilage explant. In parallel, the time-dependent degradation of cartilage was detected using mass spectrometry analysis (liquid chromatography-tandem mass spectrometry). Complement proteins resulting from activation of the classical, alternative, and terminal pathways were detected on IL-1α-stimulated cartilage at time points when clear alterations in extracellular matrix composition had occurred. Increased levels of the complement activation product C4d, as detected by ELISA in serum after incubation with IL-1α-stimulated cartilage, confirmed the selected reaction monitoring results indicating complement activation. Further, typical activated (cleaved) C3 fragments were detected by Western blotting in extracts of IL-1α-stimulated cartilage. No complement activation was triggered by cartilage cultured in the absence of IL-1α. Components released from IL-1α-stimulated cartilage during culture had an inhibitory effect on complement activation. These were released after a longer incubation period with IL-1α and may represent a feedback reaction to cartilage-triggered complement activation observed after a shorter incubation period. Copyright © 2016 by The American Association of Immunologists, Inc.

  9. Intragenic complementation by the nifJ-coded protein of Klebsiella pneumoniae.

    OpenAIRE

    Stacey, G; Zhu, J; Shah, V K; Shen, S C; Brill, W J

    1982-01-01

    A single mutation, nifC1005 (Jin et al. Sci. Sin. 23:108-118, 1980), located between nifH and nifJ in the nif cluster of Klebsiella pneumoniae, genetically complemented mutations in each of the 17 known nif genes. This suggested that the mutation is located in a new nif gene. We showed by complementation analyses that only 3 of 12 nifJ mutations tested were complemented by nifC1005. Nitrogenase activity in cell extracts of the mutant with nifC1005 as well as NifJ- mutants was stimulated by th...

  10. Perioperative functional activity of the alternative pathway of complement in patients with colonic cancer

    DEFF Research Database (Denmark)

    Baatrup, G; Zimmermann-Nielsen, E; Qvist, N

    1999-01-01

    OBJECTIVE: To investigate the functional capacity of the alternative pathway of complement in patients with cancer of the colon before, during, and after operation. DESIGN: Prospective study. SETTING: One university and two district hospitals, Denmark. SUBJECTS: 28 patients having elective...... or emergency operations for colonic cancer. INTERVENTIONS: Measurements of C3b fixing capacity of the alternative complement pathway in serum before, during, and after operation. MAIN OUTCOME MEASUREMENTS: The functional capacity of the alternative pathway of complement, and changes during operation. RESULTS......: The functional capacity of the alternative pathway in patients with cancer of the colon was above normal (p

  11. State assignment for asynchronous FSMs with the use of the incompatibility and complement graph

    Science.gov (United States)

    Kulisz, Józef

    2016-12-01

    The paper presents an application of a novel concept of graph - the Incompatibility and Complement Graph - to state assignment for asynchronous FSMs. A specific feature of the graph is that it contains two kinds of edges: connecting mutually incompatible nodes, and connecting mutually complementing nodes. The graph can be useful in certain class of optimization problems, in which compatibility of bit patterns both in the true, and in the complemented form has to be analyzed. An example of such a problem is covering analysis in state assignment for asynchronous FSMs. The paper presents a simple example explaining the method. Appropriate algorithms for the graph building and coloring are also presented.

  12. Protective role of complement C3 against cytokine-mediated beta cell apoptosis

    DEFF Research Database (Denmark)

    Dos Santos, R. S.; Marroqui, L.; Grieco, F. A.

    2017-01-01

    Background and aims: Type 1 diabetes is a chronic autoimmune disease characterized by pancreatic islet inflammation and β-cell destruction by pro-inflammatory cytokines and other mediators. The complement system, a major component of the immune system, has been recently shown to also act...... in metabolic organs, such as liver, adipose tissue, and pancreas. In the present study we identified complement C3 as an important hub of a cytokine-modified complement network in human islets and characterized the role of C3 in β-cell survival....

  13. Role of lysozyme inhibitors in the virulence of avian pathogenic Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Lise Vanderkelen

    Full Text Available Lysozymes are key effectors of the animal innate immunity system that kill bacteria by hydrolyzing peptidoglycan, their major cell wall constituent. Recently, specific inhibitors of the three major lysozyme families occuring in the animal kingdom (c-, g- and i-type have been discovered in Gram-negative bacteria, and it has been proposed that these may help bacteria to evade lysozyme mediated lysis during interaction with an animal host. Escherichia coli produces two inhibitors that are specific for c-type lysozyme (Ivy, Inhibitor of vertebrate lysozyme; MliC, membrane bound lysozyme inhibitor of c-type lysozyme, and one specific for g-type lysozyme (PliG, periplasmic lysozyme inhibitor of g-type lysozyme. Here, we investigated the role of these lysozyme inhibitors in virulence of Avian Pathogenic E. coli (APEC using a serum resistance test and a subcutaneous chicken infection model. Knock-out of mliC caused a strong reduction in serum resistance and in in vivo virulence that could be fully restored by genetic complementation, whereas ivy and pliG could be knocked out without effect on serum resistance and virulence. This is the first in vivo evidence for the involvement of lysozyme inhibitors in bacterial virulence. Remarkably, the virulence of a ivy mliC double knock-out strain was restored to almost wild-type level, and this strain also had a substantial residual periplasmic lysozyme inhibitory activity that was higher than that of the single knock-out strains. This suggests the existence of an additional periplasmic lysozyme inhibitor in this strain, and indicates a regulatory interaction in the expression of the different inhibitors.

  14. [Progress on matrix metalloproteinase inhibitors].

    Science.gov (United States)

    Lingling, Jia; Qianbing, Wan

    2017-04-01

    Continuing advances in dentin bonding technology and adhesives revolutionized bonding of resin-based composite restorations. However, hybrid layers created by contemporary dentin adhesives present imperfect durability, and degradation of collagen matrix by endogenous enzymes is a significant factor causing destruction of hybrid layers. Bond durability can be improved by using enzyme inhibitors to prevent collagen degradation and to preserve integrity of collagen matrix. This review summarizes progress on matrix metalloproteinase inhibitors (including chlorhexidine, ethylenediaminetetraacetic acid, quaternary ammonium salt, tetracycline and its derivatives, hydroxamic acid inhibitors, bisphosphonate derivative, and cross-linking agents) and suggests prospects for these compounds.

  15. Cyclodextrin Reduces Cholesterol Crystal-Induced Inflammation by Modulating Complement Activation

    DEFF Research Database (Denmark)

    Bakke, Siril S; Aune, Marie H; Niyonzima, Nathalie

    2017-01-01

    Cholesterol crystals (CC) are abundant in atherosclerotic plaques and promote inflammatory responses via the complement system and inflammasome activation. Cyclic oligosaccharide 2-hydroxypropyl-β-cyclodextrin (BCD) is a compound that solubilizes lipophilic substances. Recently we have shown...

  16. Are Religion and Environmentalism Complements or Substitutes?: A Club-Based Approach

    National Research Council Canada - National Science Library

    Feler Bose; Timothy M Komarek

    2015-01-01

    .... We use a club-based model and employ OLS and spatial econometrics with controls to test for whether membership and participation in a religious group is a substitute or complement for membership in environmental groups...

  17. Complement-mediated neutralization of dengue virus requires mannose-binding lectin

    DEFF Research Database (Denmark)

    Avirutnan, Panisadee; Hauhart, Richard E; Marovich, Mary A

    2011-01-01

    ABSTRACT Mannose-binding lectin (MBL) is a key soluble pathogen recognition protein of the innate immune system that binds specific mannose-containing glycans on the surfaces of microbial agents and initiates complement activation via the lectin pathway. Prior studies showed that MBL...... deficient in different complement components, we showed that inhibition of infection by insect cell- and mammalian cell-derived DENV was primarily dependent on the lectin pathway. Human MBL also bound to DENV and neutralized infection of all four DENV serotypes through complement activation...... hemorrhagic fever and dengue shock syndrome. Four serotypes of DENV exist, and severe illness is usually associated with secondary infection by a different serotype. Here, we show that mannose-binding lectin (MBL), a pattern recognition molecule that initiates the lectin pathway of complement activation...

  18. Expression of the membrane complement regulatory proteins (CD55 and CD59 in human thymus.

    Directory of Open Access Journals (Sweden)

    Agnieszka Kinsner

    2007-01-01

    Full Text Available CD59 is one of the key molecules involved in cell protection against autologus complement. The fact that complement regulatory proteins are able to prevent hyperacute rejection of organs in pig to primate model, raises the question of possible complement regulatory protein (CRP involvement in the maturation of immunological system. We report here that in foetal and postnatal human thymus, CD59 and CD55 are primarily located on Hassall's corpuscles and medullary epithelial cells. This localization highly correlates with the expression of CD30L, which is the member of the tumour necrosis factor superfamily. Additionally, TUNEL technique was used to visualize distribution of apoptotic cells in the thymus, which revealed the presence of apoptotic cells closely associated with the Hassall's corpuscles. The observed co-localization of CD59, CD55 and CD30L might suggest an involvement of the complement system in thymic selection in humans.

  19. Small-Angle X-ray Scattering Screening Complements Conventional Biophysical Analysis

    DEFF Research Database (Denmark)

    Tian, Xinsheng; Langkilde, Annette Eva; Thorolfsson, Matthias

    2014-01-01

    introduce small-angle X-ray scattering (SAXS) to characterize antibody solution behavior, which strongly complements conventional biophysical analysis. First, we apply a variety of conventional biophysical techniques for the evaluation of structural, conformational, and colloidal stability and report...

  20. Determination of complement to the value of thermal resistance of power semiconductor devices

    Directory of Open Access Journals (Sweden)

    V. S. Ostrenko

    2010-12-01

    Full Text Available The author justifies the procedure for determining a complement to the value of thermal resistance of a direct current semiconductor device which permits to determine a maximum temperature of the device junction when loaded by current pulses.