Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Complement C5b”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 721 records · Page 40Linked to original sources
PubMed1999

Function of the factor I modules (FIMS) of human complement component C6.

In order to elucidate the function of complement component C6, truncated C6 molecules were expressed recombinantly. These were either deleted of the factor I modules (FIMs) (C6des-748-913) or both complement control protein (CCP) modules and FIMs (C6des-611-913). C6des-748-913 exhibited approximately 60-70% of the hemolytic activity of full-length C6 when assayed for Alternative Pathway activity, but when measured for the Classical Pathway, C6des-748-914 was only 4-6% as effective as C6. The activity difference between C6 and C6des-748-913 for the two complement pathways can be explained by a greater stability of newly formed metastable C5b* when produced by the Alternative Pathway compared with that made by the Classical Pathway. The half-lives of metastable C5b* and the decay of (125)I-C5b measured from cells used to activate the Alternative Pathway were found to be about 5-12-fold longer than those same parameters derived from cells that had activated the Classical Pathway. (125)I-C5 binds reversibly to C6 in an ionic strength-dependent fashion, but (125)I-C5 binds only weakly to C6des-FIMs and not at all to C6des-CCP/FIMs. Therefore, although the FIMs are not required absolutely for C6 activity, these modules promote interaction of C6 with C5 enabling a more efficient bimolecular coupling ultimately leading to the formation of the C5b-6 complex.

Animals↗
PubMed2001

Glomerular complement regulation is overwhelmed in passive Heymann nephritis.

BACKGROUND: An injection of anti-Fx1A antibodies in rats leads to passive Heymann nephritis (PHN), a model of membranous nephropathy. Fx1A is a crude extract of renal cortex that contains megalin as a principal component. However, when rats are given anti-megalin antibodies, abnormal proteinuria does not occur. Because of the established complement dependence of PHN, we hypothesized that antibodies neutralizing complement regulatory proteins in the rat glomerulus also were required to induce PHN. Two likely targets are Crry and CD59, proteins abundant on the rat podocyte and contained within Fx1A that inhibit the C3 convertase and C5b-9 assembly, respectively. METHODS: Rats were injected with anti-megalin monoclonal antibodies, followed by anti-Crry and/or anti-CD59 F(ab')(2) antibodies five days later. In a second group of experiments, rats were injected with anti-Fx1A or anti-Fx1A immunodepleted of reactivity against Crry and/or CD59. RESULTS: In the setting of podocyte-associated anti-megalin monoclonal antibodies, simultaneous neutralization of Crry and CD59 function led to the development of significant proteinuria (11.0 +/- 2.1 mg/day, P < 0.001 vs. all other groups). In contrast, animals that had neither or only one of these complement regulators inhibited had normal urinary protein excretion (< or =6 mg/day). In animals given anti-Fx1A depleted of anti-Crry and/or anti-CD59, all groups developed typical PHN, characterized by heavy proteinuria and extensive glomerular deposition of C3 and C5b-9. CONCLUSION: Crry and CD59 play an important role in restraining complement-mediated injury following subepithelial immune complex deposition; however, in PHN, their regulatory capacity is overwhelmed.

Animals↗
PubMed2003

Inhibition of C5a-induced inflammation with preserved C5b-9-mediated bactericidal activity in a human whole blood model of meningococcal sepsis.

The complement system plays an important role in the initial defense against Neisseria meningitidis. In contrast, uncontrolled activation in meningococcal sepsis contributes to the development of tissue damage and shock. In a novel human whole blood model of meningococcal sepsis, we studied the effect of complement inhibition on inflammation and bacterial killing. Monoclonal antibodies (mAbs) blocking lectin and alternative pathways inhibited complement activation by N meningitidis and oxidative burst induced in granulocytes and monocytes. Oxidative burst was critically dependent on CD11b/CD18 (CR3) expression but not on Fc gamma-receptors. Specific inhibition of C5a using mAb 137-26 binding the C5a moiety of C5 before cleavage prohibited CR3 up-regulation, phagocytosis, and oxidative burst but had no effect on C5b-9 (TCC) formation, lysis, and bacterial killing. An mAb-blocking cleavage of C5, preventing C5a and TCC formation, showed the same effect on CR3, phagocytosis, and oxidative burst as the anti-C5a mAb but additionally inhibited TCC formation, lysis, and bacterial killing, consistent with a C5b-9-dependent killing mechanism. In conclusion, the anti-C5a mAb 137-26 inhibits the potentially harmful effects of N meningitidis-induced C5a formation while preserving complement-mediated bacterial killing. We suggest that this may be an attractive approach for the treatment of meningococcal sepsis.

Antibodies, Monoclonal↗
PubMed2005

The gamma subunit of the eighth complement component (C8) in rainbow trout.

Of the 35 proteins, enzymes, receptors and regulatory components of the complement system, C8gamma is unique in that it is the only lipocalin. C8gamma is a subunit of the C8 molecule, which is one of the five components (C5b, C6, C7, C8 and C9) that interact as a consequence of complement activation to form the membrane attack complex. Until now, C8gamma has been characterized only in mammalian species. In order to elucidate the phylogeny of this molecule, we have cloned the C8gamma subunit in rainbow trout (Oncorhynchus mykiss), a teleost fish representing a critical point in the evolutionary divergence of the complement system. The deduced amino acid sequence of trout C8gamma shows significant identity (37%) to the human C8gamma homolog and much lower to the other known lipocalins. The lipocalin domain is present and all the cysteine residues are conserved. The trout C8gamma gene is probably present as a single copy in the trout genome showing a differential expression pattern among tissues investigated.

Amino Acid Sequence↗
PubMedDate not supplied

Complement activation and atherosclerosis.

Atherosclerosis is an inflammatory disease mediated through the action of monocyte/macrophages, complement and T-lymphocytes. C5a and monocyte chemotactic factor released during complement activation in the arterial wall may participate in the initial monocyte recruitment. Assembly of C5b-9 on cells of the arterial wall may also induce cell lysis. On the other hand, sublytic assembly of C5b-9 on smooth muscle cells (SMC) and endothelial cells (EC) induces cell activation and proliferation. Analysis of mitogen activated protein kinases (MAPK) pathways induced by C5b-9 in aortic SMC revealed that extracellular signal regulated kinase (ERK) 1, c-jun NH2-terminal kinase (JNK) 1, and p38 MAPK are all activated by C5b-9. ERK1 activity was inhibited by wortmannin suggesting that ERK1 pathway is activated through phosphatidyl inositol -3 (PI 3-) kinase. Sublytic C5b-9 assembly on the plasma membrane was also able to activate Janus kinase (JAK) 1, signal transducer and activator (STAT) 3 and STAT4 in EC. JAK1 but not STAT3 activation induced by C5b-9 is dependent on Gi protein activation. New evidence accumulated during the last decade support the role of complement activation in both initiation and progression of the atherosclerotic lesions. Complement system activation is a major component of the chronic inflammatory process associated with atherosclerosis.

Animals↗
PubMed1985

Complement-mediated serum cytotoxicity for Leishmania major amastigotes: killing by serum deficient in early components of the membrane attack complex.

Leishmania major, the agent of Oriental sore, is an obligate intracellular parasite of macrophages in mammalian hosts. Man's immune defense against this organism requires participation of specifically sensitized lymphocytes and activated macrophages. Recent studies, however, have demonstrated that as little as 1/120 concentration of normal human serum is highly cytotoxic for the amastigote form of L. major. Initiation of the lethal process occurs rapidly, requiring only 30 sec of parasite exposure to serum, and is mediated by antibody-independent activation of the alternate complement pathway. The molecular mechanism of cytotoxicity is not known, but may require participation of the membrane attack complex, C5b-9. We investigated this possibility by treating amastigotes with human sera genetically deficient in complement components C5, 6, 7, 8, or 9. We then measured viability of treated parasites by amastigote-promastigote conversion. Our results were quite unexpected: not only did C9-deficient serum kill organisms, but sera singly deficient in each of the preceding components C6 to C8 were also cytotoxic. The degree of cytotoxicity was related both to serum concentration and to the point in the complement cascade at which deficiency occurred. Sera lacking C6 or C7 were less cytotoxic than those deficient in C8, which were less toxic than those deficient in C9. Cytoxicity of deficient sera was abolished by heating serum to 56 degrees C for 30 min. These findings indicate that an incomplete membrane attack complex may mediate cytotoxicity for L. major amastigotes. Moreover, our results raise important questions regarding the mechanism by which the complex is assembled on the surface of a living, unicellular eukaryotic organism.

Animals↗
PubMed2000

The complement regulators C1 inhibitor and soluble complement receptor 1 attenuate acute lung injury in rabbits.

Because activation of the complement system plays a major role in the pathogenesis of acute lung injury, the availability of new specific complement inhibitors represents a promising therapeutic approach. In the present study we investigated pulmonary edema formation and pulmonary artery pressure (PAP) in acute complement-induced lung injury for possible therapeutic impact of the complement regulators C1 inhibitor and soluble complement receptor 1. Eighteen isolated and ventilated rabbit lungs were perfused with pooled normal human serum (NHS, final concentration 35%) in Krebs-Henseleit buffer in a recirculating system. Lung weight gain and PAP were continuously recorded. Complement activation was blocked by the addition of C1 inhibitor (1.0 U/mL, n = 6) or sCR 1 (2.0 microg/mL, n = 6). Lungs that received NHS without inhibitors served as controls (n = 6). This study was performed according to the Helsinki Declaration and approved by the local government. Application of NHS resulted in an increase of PAP within 20 min from 8+/-2 to 42+/-6 mmHg, which was significantly (P < 0.05) decreased by C1-Inh (25+/-5 mmHg) and sCRI (20 +/-3 mmHg). Moreover, pulmonary edema formation after NHS, as assessed by overall weight gain, was reduced by both C1-Inh and sCR1, compared with controls. These findings were paralleled with significantly decreased thromboxane release rates and reduced tissue deposition of C3c and C5b-9. C1 inhibitor and sCR1 attenuate the complement-induced pulmonary capillary leakage and PAP increase, indicating the protective effect of complement inhibition in isolated perfused rabbit lungs.

Animals↗
PubMed2000

Complement activation by anti-endothelial cell antibodies in MHC-mismatched and MHC-matched heart allograft rejection: anti-MHC-, but not anti non-MHC alloantibodies are effective in complement activation.

Classical complement activation is a major effector mechanism in the development of vascular lesions contributing to allograft rejection. We investigated complement activation by alloantibodies reactive with graft endothelial cell (EC) alloantigens in settings of MHC-mismatched and MHC-matched (non-MHC-mismatched) rat heart transplantation (Tx). Allosera and heart allografts were collected at the day of rejection (day 7-8 and day 28-35 in MHC-mismatched and non-MHC-mismatched Tx respectively) or earlier. Allosera reactivity was studied in vitro using rat-heart-endothelial-cell (RHEC) lines expressing the appropriate donor MHC and non-MHC alloantigen profile. Immunohistochemical analysis of rejected heart allografts showed deposition of alloantibodies in both MHC-mismatched and MHC-matched heart allografts, but expression of C3 was only seen in the vasculature of MHC-mismatched grafts. FACS analysis showed that anti MHC as well as anti non-MHC allosera were reactive with donor EC cell surface antigens. Both sera had similar IgG subclass profiles of anti-endothelial cell antibodies. Complement activation by anti MHC and anti non-MHC alloantibodies on EC was measured by FACS analysis of C3 and C5b-9 (MAC) expression. Distinct expression of C3 was noticed for EC incubated with anti-MHC allosera, but hardly for EC incubated with anti non-MHC allosera. C5b-9 was low but showed no difference between the two allosera. However, complement-mediated cytotoxicity experiments showed that functional (lytic) MAC was induced with anti MHC allosera but hardly with anti non-MHC allosera. Our data show that in settings of MHC-matched heart transplantation alloantibodies against endothelial non-MHC alloantigens are generated, but, in contrast to alloantibodies to MHC alloantigens, these alloantibodies have only poor complement-activating and lytic potentials. Whether anti non-MHC allolantibodies effect other biological processes relevant for heart allograft vasculopathy, including development of graft arteriosclerosis, needs further elucidation.

Animals↗
PubMed1986

Release of arachidonic acid and formation of oxygenated derivatives after complement attack on macrophages: role of channel formation.

Treatment of [3H]arachidonic acid ([3H]C20:4)-labeled, antibody-sensitized mouse resident peritoneal macrophages with rabbit serum complement, or C6-deficient rabbit serum + C6, caused hydrolytic release of incorporated [3H]C20:4 from phospholipids, followed by conversion to oxygenated derivatives. The C6 dose-response curve for release of C20:4 plus its metabolites was monotonic, which indicates dependence on channel formation, whereas the dose-response curve for lysis displayed multi-hit behavior. High-performance liquid chromatography demonstrated that the major radiolabeled products in the aqueous phase co-eluted with C20:4, 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), and prostaglandin E2. Kinetic studies of the release of 6-keto-PGF1 alpha, the major metabolite, displayed biphasic characteristics; a moderate amount of this prostaglandin was released before the onset of cell lysis. Experimental evidence obtained by freeze-thaw or by incubation of these cells with melittin or A23187 indicated that cell lysis does not necessarily result in the production of inflammatory mediators. Furthermore, when macrophages were treated with serum complement, it was apparent that the major part of the release was due to C5b-9 and not to the action of C5a. We conclude that release of C20:4 and its derivatives from complement-treated macrophages does not depend on cytolysis, but is a consequence of insertion and channel formation.

Animals↗
PubMed1994

Loin pain-hematuria syndrome with a distinctive vascular lesion and alternative pathway complement activation.

We describe a 48-year-old woman with loin pain-hematuria syndrome. Her renal abnormalities included conspicuous microaneurysmal and glomeruloid (plexiform) angiomatous changes. The deposition of both properdin and the C5b-9 complex, as well as the usual C3, in arterioles argues for complement activation. To our knowledge, neither of these features has been previously described. We speculate about the cause of loin pain-hematuria syndrome and note the uncommonness of this entity in the United States as opposed to Great Britain.

Complement Pathway, Alternative↗
PubMed2002

CD59 prevents human complement-mediated injuries in isolated guinea pig hearts.

OBJECTIVE: To assess complement-mediated myocardial injury on isolated guinea pig working hearts and cardioprotective effects of CD59. METHODS: Using a modified Langendorff apparatus, isolated guinea-pig working hearts were perfused with a modified Krebs Henseleit buffer containing 3% heat-inactivated human plasma and zymosan (IPZ) (control) (n = 10), 3% normal human plasma and zymosan (NPZ) (n = 10), or 3% normal human plasma and zymosan and 1.5 microg/ml CD59 (NPZC) (n = 10), respectively. Epicardial electrocardiogram (ECG), cardiac output (CO), coronary arterial flow (CF), maximum left ventricular developed pressure (LVP(max)), maximum left ventricular developed pressure increase rate (+ dp/dt(max)), maximum left ventricular developed pressure decrease rate (- dp/dt(max)) and heart rate (HR) were recorded at 0, 15, 30, 45 and 60 min of treatment. After the experiment, immunohistochemical examination was performed to detect the presence of C3a or C5b-9 in the myocardium of the isolated hearts. RESULTS: Compared the IPZ group, hearts treated with NPZ showed a slight depression on ST segments of epicardial ECG at 15 min, a significant elevation between 30 min to 60 min, a decrease in CF, CO, LVP(max), + dp/dt(max) and - dp/dt(max), and an increase in HR at 15 min. The observed alterations in CF, CO, LVP(max), + dp/dt(max) and - dp/dt(max) remained decreased, while the HR remained increased until the end of the protocol. The all above parameters of hearts treated with NPZC were similar to the control group (IPZ) at any given time. Immunohistochemical examination showed positive signals of C3a and C5b-9 in the myocardium of hearts treated with NPZ. C3a was positive in NPZC, and C3a and C5b-9 were negative in IPZ. CONCLUSIONS: Activated human complements directly damage isolated guinea pig working hearts, and CD59 offers a significant protection against the injuries.

Animals↗
PubMed1990

Functions and relevance of the terminal complement sequence.

The terminal complement sequence is initiated upon cleavage of C5 with liberation of C5a anaphylatoxin, and involves the assembly of macromolecular C5b-9 complexes either on cell surfaces or in plasma. Cell-bound C5b-9 complexes generate transmembrane pores that can cause cell death, or they can elicit secondary cellular reactions triggered, for example, by passive flux of calcium ions into the cells. In vivo functions of the fluid-phase SC5b-9 complex have not yet been defined, but the identity of S-protein with vitronectin (serum spreading factor) provokes the anticipation that significant biological functions of this complex do exist. The terminal complement sequence may fulfil protective functions when it is triggered on alien cells that are marked for destruction. Dysregulation in the complement sequence may, however, result in detrimental attack by C5b-9 on autologous cells. Examples include not only autoimmune disease states, but also the activation of complement on dead or dying cells, and bystander attack on blood cells during cardiopulmonary bypass. Methods for detecting and quantifying C5b-9 are outlined, and the potential usefulness of such assays in clinical research is discussed.

Complement C3-C5 Convertases↗
PubMed1990

[Functions and relevance of the terminal complement sequence].

The terminal complement sequence is initiated upon cleavage of C5 with liberation of C5a anaphylatoxin, and involves the assembly of macromolecular C5b-9 complexes either on cell surfaces or in plasma. Cell-bound C5b-9 complexes generate transmembrane pores that can cause cell death, or they can elicit secondary cellular reactions triggered, for example, by passive flux of calcium ions into the cells. In vivo functions of the fluid-phase SC5b-9 complex have not yet been defined, but the identity of S-protein with vitronectin (serum spreading factor) provokes the anticipation that significant biological functions of this complex do exist. The terminal complement sequence may fulfill protective functions when it is triggered on alien cells that are marked for destruction. Dysregulation in the complement sequence may, however, result in detrimental attack by C5b-9 on autologous cells. Examples include not only autoimmune disease states, but also the activation of complement on dead or dying cells, and bystander attack on blood cells during cardiopulmonary bypass. Methods for detecting and quantifying C5b-9 are outlined, and the potential usefulness of such assays in clinical research is discussed.

Animals↗
PubMed2000

Damage to porcine islets of Langerhans after exposure to human blood in vitro, or after intraportal transplantation to cynomologus monkeys: protective effects of sCR1 and heparin.

BACKGROUND: Porcine islets offer an attractive alternative to human islets in clinical islet transplantation. The preferred method of islet transplantation is intra-portal injection into the liver. We have recently shown, both in vitro with human islets and in vivo with porcine islets, that islets exposed to allogeneic blood trigger an injurious inflammatory reaction characterized by activation of both coagulation and the complement systems. We have now tested whether a similar reaction is triggered when xenogeneic porcine islets are exposed to human blood in vitro and after intraportal transplantation into primates. Furthermore, we investigated the effect of inhibiting the complement and coagulation systems. METHOD: Islets isolated from adult and fetal porcine pancreas were perfused with fresh human blood in surface heparinized PVC tubings for 5-60 min. Blood cell counts and parameters related to coagulation and the complement system were analyzed, and islets were retrieved after the perifusion was examined by immunohistochemical method. Heparin and soluble complement receptor 1 (sCR1; TP10, 100 microg/ml) were added to the system in some experiments. Furthermore, adult porcine islets were transplanted intraportally into untreated and sCR1- (40 mg/kg BW i.v.) treated cynomolgus monkeys, and plasma insulin concentration was monitored during 60 min after transplantation. RESULTS: Porcine islets perifused with human blood triggered an immediate inflammatory reaction, characterized by a rapid consumption and activation of platelets, consumption of neutrophils and monocytes, activation of the coagulation and complement systems, and release of large amounts of insulin. Islet morphologic analysis revealed damaged islets embedded in clots and infiltrated with CD11+ leukocytes. C3a and C5b-9 was deposited on the islet surface, but human immunoglobulin was not. Complement inhibition with sCR1 reduced insulin release significantly. Intraportal islet transplantation into untreated cynomolgus monkeys resulted in a marked and rapid increase in plasma insulin concentration indicative of islet damage. Pretreatment of the monkeys with sCR1 resulted in significantly less insulin release than in untreated control monkeys. CONCLUSION: Exposure of isolated xenogeneic islets of Langerhans to blood, both in vitro and in vivo, resulted in acute islet damage. Complement and platelets seem to have a central role in the reactions described. Strategies to efficiently inhibit these reactions will be crucial for clinical intraportal islet xenotransplantation to be successful.

Animals↗
PubMed1990

Lack of complement activation in the seminal plasma of men with antisperm antibodies associated in vivo on their sperm.

A specific and sensitive "sandwich"-type radiolabeled antiglobulin assay (RAA) using monoclonal anti-human C5b-9 neoantigen and polyclonal anti-human C5b-9 was used to evaluate the presence of the in vivo product of human complement (C) activation (SC5b-9) in the seminal plasma (SP) of 19 fertile and 61 infertile men. SP SC5b-9 was detectable in 7 (8.7%; 1 fertile and 6 infertile men) of the 80 men with a range of 10 to 175 ng/ml. Levels of SP SC5b-9 in other men were below the limit of detection (less than 10 ng/ml). Of the 33 infertile men with sperm-associated immunoglobulin (Ig) G and/or IgA, 27 (82%) had undetectable levels of SP SC5b-9 immunoreactivity. There was no correlation between the SP SC5b-9 levels and the degree of sperm-associated IgG (r = 0.086) or IgA (r = 0.23) activity. However, significant deposition of sperm-bound C5b-9 due to autologous C activation was demonstrated by flow cytometry of donor sperm treated with sera from autoimmune men with ASA in their sera and on their sperm. These findings suggest that sperm-bound Ig cannot activate C in SP.

Autoantibodies↗
PubMed1996

Analysis of complement C3 deposition and degradation on Klebsiella pneumoniae.

The majority of Klebsiella pneumoniae serum-resistant strains activate complement and bind C3b, the opsonic fragment of C3, without C5b-9 formation and bacterial killing. The mechanisms leading to C3b deposition without cell death were studied, and the results indicate that serum-resistant strains activate principally the alternative pathway and that serum-sensitive strains activate both the alternative and classical pathways. Bacterial molecules implicated in C3b deposition are the outer membrane porin proteins and smooth and rough lipopolysaccharides. Porins activate both complement pathways, and the rough lipopolysaccharide activates the classical pathway, causing deposition of C3b in serum-sensitive strains. The smooth lipopolysaccharide of serum-resistant strains activates only the alternative pathway, impeding the binding of C1q to porins (S. Albertí, G. Marqués, S. Camprubí, S. Merino, J. M. Tomás, F. Vivanco, and V. J. Benedí, Infect. Immun. 61:852-860, 1993; S. Albertí, F. Rodríguez-Quinónes, T. Schirmer, G. Rummel, J. M. Tomás, J. P. Rosenbusch, and V. J. Benedí, Infect. Immun. 63:903-910, 1995) and rough lipopolysaccharide molecules and thereby preventing activation of the classical pathway. After its deposition, C3b is quickly degraded to iC3b on both types of strains, but the higher-level deposition of C3b on serum-sensitive strains, resulting from activation of both the alternative and classical complement pathways, supports further complement activation and killing of serum-sensitive strains.

Bacterial Proteins↗
PubMed1997

Complement activation in Henoch-Schönlein purpura.

The pathogenetic mechanism underlying Henoch-Schönlein purpura (HSP) is poorly understood. Complement activation has been thought to have a role, but despite the demonstration of complement components in skin and renal biopsy material, serological evidence of complement activation is not convincing. We have assessed complement activation in 64 children with acute HSP. We used an enzyme-linked immunosorbent assay to measure plasma levels of three multimolecular complement activation protein (CAP) complexes: C1r:C1s:C1-inhibitor, C3bP and C5b-9. We found no significant difference between the levels of CAPs in children with acute HSP and a control group of children. This study does not support a role for complement activation in the pathogenesis of HSP.

Adolescent↗
PubMed1996

Complement activation on thiol-modified gold surfaces.

To evaluate the importance of protein adsorption and chemical composition of the solid surface on complement activation, we used mercaptoglycerol (MG) and mercaptopropionic acid (MPA) modified gold surfaces as model surfaces. The complement activation by these surfaces was determined by measuring fluid phase iC3b and C5b-9 in serum that had been in contact with the surfaces. In addition, "active" C3 deposition at the modified surfaces was measured with the use of ellipsometry, an optical technique. It was found that the MG surface caused pronounced productions of iC3b and C5b-9 in serum as well as increased C3 deposition on the surface. In contrast, the bare gold surface and the MPA surface caused very little complement activation. The MG surface seems to have a high affinity with immunoglobulin G (IgG) that may be one explanation for the high complement activation ability of the MG surface. However, complement activation at the MG surface was relatively insensitive to Mg-EGTA buffer at a high serum concentration, indicating alternative pathway activation when classical pathway activation was inhibited. Corresponding control experiments performed with Mg-EGTA serum at hydrophobic silicon surfaces precoated with IgG showed no sign of alternative pathway activation. At a lower serum concentration, classical pathway activation seemed to dominate at the MG surface and the hydrophobic silicon surface precoated with IgG. Most probably, it is the hydroxyl groups at the MG surface that are associated with alternative pathway activation.

3-Mercaptopropionic Acid↗