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[The humoral immunity indices of rhesus monkeys under the action of extreme factors in space flight].

Some features of nonspecific resistance of rhesus monkeys (G and A immunoglobulins and C3 complement component) are studied. Standards of IgG, IgA and C3 complement component in healthy rhesus monkeys are determined. The changes in the parameters of nonspecific resistance of the animals in all stages of their preflight training and shortly after flight experiment are examined. These alterations were appeared first of all as an increase in IgA level.

Animals↗
PubMed1981

Circulating immune complexes, complement factors C3, C4, C1-inhibitor, alpha-1-antitrypsin and immunoglobulins in asthmatic patients.

Sera from 159 adult asthmatic outpatients (extrinsic, n = 82, intrinsic, n = 65 and acetylosalicylic acid (ASA)-sensitive, n = 12) and from 100 controls were tested for total levels of IgG, IgM, IgA, IgE, complement factors C3, C4, C1-inhibitor, alpha 1-antitrypsin and circulating immune complexes. The following results were observed: (1) a marked increase of IgE in extrinsic asthma; (2) a slight increase of IgM, and (3) an equal increase of complement C4 levels in all three asthma groups; (4) normal mean values of C3 levels with a significantly larger standard deviation of the mean in all three asthma groups; (5) an equally slight decrease of protease inhibitors, such as C1-inhibitor and alpha 1-antitrypsin, and (6) the presence of circulating immune complexes in 22% of extrinsic, in 8% of intrinsic and 13% of ASA-sensitive asthmatics. Circulating immune complexes can be found in all three asthma groups and may correlate with complement deviation.

Adult↗
PubMed1988

Comparative studies on immunoglobulins, complement component (C3), albumin, and immunoglobulin A-containing circulating immune complexes in serum and bile of patients with biliary obstruction.

We measured the concentrations of IgA, IgG, IgM, secretory IgA, albumin, complement component (C3), and IgA-containing circulating immune complex (IgA-CIC) in the serum and bile of patients with biliary obstruction. The bile-to-serum (BS) ratio of the concentrations of albumin and IgG increased with the increase in total serum bilirubin. This indicates that the permeability from blood to bile increases with the degree of biliary obstruction, and the blood-bile barrier function breaks down. The BS ratios of IgA and IgM, which are selectively secreted into bile, did not show a significant correlation with total serum bilirubin. The index of the BS ratio to the BS ratio of albumin (BS/BS-Alb index) of IgA and IgM was significantly larger than that of IgG. This indicates that the selective transport of IgA and IgM into bile is present even in patients with obstructive jaundice. Since the BS/BS-Alb index of C3 is larger than that of IgG, and the SGOT correlated directly with the BS ratio of C3, some of the C3 in bile may come from damaged hepatocytes.

Albumins↗
PubMed1993

Drug metabolism and genetic polymorphism in subjects with previous halothane hepatitis.

To test the hypothesis that halothane hepatitis is caused by a combination of altered drug metabolism and an immunoallergic disposition, the metabolism of antipyrine, metronidazole, sparteine, phenytoin, and racemic R- and S-mephenytoin was investigated in seven subjects with previous halothane hepatitis. The HLA tissue types and the complement C3 phenotypes were also determined. The metabolism of antipyrine and metronidazole was within normal range in all subjects, and they were all fast or extensive metabolizers of sparteine, mephenytoin, and phenytoin. HLA tissue types were unremarkable. Five of the seven subjects had complement C3 phenotypes F or FS. In the general population phenotype S is the most common, but the difference in complement C3 phenotypes is not statistically significant (p = 0.07). We conclude, although in a limited number of patients, that subjects with previous halothane hepatitis do not appear to be different from controls with regard to drug metabolism and HLA tissue type. The possibility of a higher frequency of complement C3 phenotype F and FS needs further investigation.

Adult↗
PubMed1993

[Immunologic follow-up of HIV-positive patients. C3, C4 complement components during HIV infection].

Investigations of the authors' patients with HIV infection revealed marked changes in the C3 and C4 components of complement. Of 61 investigated patients with HIV infection only 23 patients (37.7%) had values of the C3 component at the level recorded in controls. Values of the C4 component comparable with the control group were recorded in 24 patients (39.3%). From figures 1 and 2 it apparent that in the investigated group there is a striking hypercomplementaemia of both components, as compared with hypocomplementaemia.

AIDS-Related Complex↗
PubMed2003

Nickel and cobalt activate complement factor C3 faster than magnesium.

We have found that incubation of heparin plasma with Ni(2+) or Co(2+) at concentrations below 100 microM can stimulate the conversion of complement factor C3 to C3b faster than magnesium, which is the natural cofactor in the alternative complement activation. This conversion was monitored by light absorbance measurement after separation by isotachophoresis, immunofixation and protein staining. The generation of C3b stimulated by these metals (<0.5 mM) proceeds up to about four times faster than the stimulation by Mg(2+). Half of total C3 in the incubation media was converted by Ni(2+) or Co(2+) at 0.5 mM after 20 min at 37 degrees C. Increasing Ni(2+) concentrations over 0.5 mM decreased the C3 conversion rate. Activation of C3 stimulated by Ni(2+), Co(2+) and Mg(2+) was concomitant with the conversion of complement factor B to Bb, but complement factor C4 was not affected by the activation. The conversion of B to Bb was monitored after separation by isotachophoresis and immunoblotting. Other divalent metal ions tested, namely Ca(2+), Ba(2+), Cu(2+) and Zn(2+), did not stimulate the complement cascade. We postulate that the increased rate of C3-fragment production induced by nickel or cobalt ions is central for the immunotoxicity of these metals.

Animals↗
PubMed2004

[Does the assay of acute phase protein concentrations in cerebrospinal fluid and/or in serum in patient with viral meningitis have a diagnostic value? Part II. Lymphocytic meningitis caused by echo 30 virus].

The aim of the study was to evaluate dynamics of selected acute phase proteins in serum and cerebrospinal fluid (CSF) in children with viral meningitis and to assess diagnostic power of protein determination for detection and treatment monitoring. 51 children with viral meningitis caused by ECHO 30 virus were included in the study group. Concentration of C-reactive protein (CRP), alpha 1-antitrypsin (AAT), alpha1-acid glycoprotein (AAG), alpha2-haptoglobin (HPT) and C3 complement fragment were determined in serum and CSF at entry and at day 14 after admittance to hospital. Control group for serum determination consisted in 30 healthy children (Group K1) and control group for CSF determination consisted in 19 hospitalized children in whom the diagnosis of meningitis was not confirmed (group K2). The greatest rise of acute phase proteins concentration was observed in children in case of HPT, AAG and C3 complement when determined in serum. Meningitis in children that was caused by ECHO 30 virus produces slight acute phase reaction that is more evident in serum than in CSF. It is confirmed by remarkable increase of AAG, HPT, C3 complement in serum and HPT in CSF either at entry or at the day 14. The determination of AAG, HPT and C3 complement in serum have diagnostic power that is strong enough to meningitis diagnostics and monitoring of treatment.

Acute-Phase Proteins↗
PubMed1994

Differential recognition by conglutinin and mannan-binding protein of N-glycans presented on neoglycolipids and glycoproteins with special reference to complement glycoprotein C3 and ribonuclease B.

Conglutinin and mannan-binding protein are serum proteins that have similar carbohydrate binding specificities toward high mannose-type oligosaccharides, and yet only conglutinin binds the complement glycoprotein iC3b, which contains oligosaccharides of this type. In the present study, the interactions of conglutinin and mannan-binding protein were evaluated with the complement glycoprotein C3, including various physiologically derived fragments of this glycoprotein, and neoglycolipids prepared from oligosaccharides released from C3 and its isolated alpha and beta chains. Several conclusions can be drawn. First, the interaction of conglutinin is profoundly influenced by the state of the protein moiety of the alpha chain in the vicinity of the glycosylation site Asn-917. Second, the binding to the C3-derived glycoprotein iC3b appears to be exclusively mediated through the Man8 or Man9 oligosaccharide on the alpha chain; there is no evidence for other N-linked oligosaccharides on C3 that are uniquely bound by conglutinin. Third, although conglutinin shows a more restricted binding relative to mannan-binding protein toward the oligosaccharides free of protein, it has a broader binding pattern toward the oligosaccharides as presented on C3-derived glycoproteins. From these and additional observations with RNase B, which contains high mannose-type oligosaccharides at Asn-34, it is clear that the protein moieties of these glycoproteins markedly influence the presentation of the oligosaccharides such that biological specificity is mediated by the commonly occurring high mannose-type oligosaccharides in the context of specific carrier proteins.

Blood Proteins↗
PubMed1989

Conservation of structural and functional domains in complement component C3 of Xenopus and mammals.

The cDNA sequence and the deduced amino acid sequence of the Mr 34,000 C-terminal fragment of Xenopus laevis complement component C3 are presented. The sequence of Xenopus C3 has 57% nucleotide identity to the corresponding sequence of human C3 and approximately 49% amino acid identity to C3 from human, mouse, and rabbit. The Xenopus C3 sequence shows clusters of high and of low similarity to the mammalian C3 sequences. One of these regions of high similarity represents the domain of mammalian C3b involved in the binding of properdin, a regulator of the alternative pathway of complement activation. It is not clear whether the other highly conserved regions are involved in binding to other C3 ligands. The Xenopus C3 sequence completely lacks the Arg-Gly-Asp sequence, which has been suggested to be the recognition site of the human complement receptor type 3 on the iC3b fragment of human C3. The Xenopus C3 gene is shown not to be linked to the Xenopus major histocompatibility complex, as is also the case in mammals. Since the gene of the related molecule C4 is MHC-linked in both mammals and Xenopus, the C3 and C4 genes may have separated before Xenopus and mammals speciated.

Amino Acid Sequence↗
PubMed1986

A novel polymorphism of human complement component C3 detected by means of a monoclonal antibody.

A mouse monoclonal antibody, HAV 4-1, obtained after immunization of a BALB/c mouse with purified C3F, detected a novel genetic polymorphism of human complement component C3 in a simple immunoblotting system. The frequency of HAV 4-1-positive genes was 20.1%. Reactivity of HAV 4-1 was closely related to C3F, but certain individuals with the C3F allele did not react with HAV 4-1. Conversely, certain C3S homozygous individuals did react with HAV 4-1. The polymorphism detected by this monoclonal antibody is therefore different from the previously described polymorphism based on charge differences.

Alleles↗
PubMed1991

Levels of complement factor C3 and its activated product, C3a, in operatively salvaged blood.

In intra-operative blood salvage the collected blood is exposed to traumatized tissue and a synthetic circuit. Because of this exposure it was expected that the complement system, which is a contact system present in plasma, would be activated in salvaged blood. To determine whether this occurs, the plasma levels of the complement factor C3 and its activated fragment, C3a, were measured in intra-operative salvaged blood before and after washing. Samples were obtained from patients undergoing aortic surgery where intra-operative salvage was used. In the unwashed salvaged blood, the level of C3 fell (mean C3: 0.33 g/L) and the level of C3a increased (mean C3a: 1994 ng/mL) compared with the patient circulating levels of C3 and C3a (mean C3: 0.70 g/L, mean C3a: 855 ng/mL) respectively. Washing of the collected blood reduced the C3a level (mean: 346 ng/mL) to the patient's level and reduced C3 to the lower detection limit of the test (less than 0.2 g/L). The raised level of C3a and the reduced level of C3 confirm that the complement system is activated and imply that other complement factors are also activated.

Blood Loss, Surgical↗
PubMed1993

Immunoelectron microscopic study on IgA, secretory component and complement component C3 in the liver of children undergoing total parenteral nutrition through neonatal period.

To study the mechanism of the intrahepatic cholestasis observed during total parenteral nutrition (TPN) in neonates, we examined the localization of IgA, secretory component (SC) and complement component C3 (C3) in the liver in 4 patients by light and electron microscopic immunohistochemistry. In the patients who received TPN for 1 month, IgA- and SC-positive cholestasis was limited to bile canaliculi, but the integrity of both the canalicular wall and intercellular tight junction was maintained. These findings suggest that obstruction in the biliary tract develops at the canalis of Hering, causing reflux of IgA and SC into the bile canaliculi. When the duration of TPN extended beyond 6 months, the cholestasis in bile canaliculi progressed further, and degeneration of hepatocytes became more marked. Bile retained in hepatocytes occasionally contained IgA and SC. IgA- and SC-positive cholestasis also developed in the interlobular bile ducts, where no cholestasis had been observed 1 month after the beginning of TPN. SC production and SC-mediated transport of IgA, which are important functions of bile duct epithelial cells in the local immune mechanism, were impaired in association with the injury of those cells. C3 was localized not only in the hepatocellular organelles where C3 is normally observed, but also in the lumen of dilated bile canaliculi, suggesting that C3 is released from hepatocytes into bile in neonates receiving TPN and that C3 may be involved in some local immune mechanism of biliary system.

Complement C3↗
PubMed1984

Complement-component-C3-opsonized immunoglobulin G anti-DNA antibodies do not bind effectively to red blood cells unless aggregated on a high-Mr DNA matrix.

Large, soluble ds (double-stranded) DNA-IgG (immunoglobulin G) anti-dsDNA immune complexes (greater than or equal to 200 S) that were previously opsonized with complement were digested with DNAase. The small complement-component-C3-fragment-labelled IgG (11-14 S) that was then isolated did not bind effectively to complement receptor type 1 on human red blood cells. However, when this IgG was immune-complexed with 3H-labelled PM2 (bacteriophage directed against a marine Pseudomonas) dsDNA (Mr approximately 6 X 10(6), substantial binding of both the DNA antigen and IgG to the erythrocytes was demonstrable.

Antigen-Antibody Complex↗
PubMed2002

Local synthesis of complement component C3 regulates acute renal transplant rejection.

Accumulating evidence suggests that innate immunity interacts with the adaptive immune system to identify potentially harmful antigens and eliminate them from the host. A central facet of innate immunity is complement, which for some time has been recognized as a contributor to inflammation in transplant rejection but without detailed analysis of its role in what is principally a T cell mediated process. Moreover, epithelial and vascular tissues at local sites of inflammation secrete complement components; however, the role of such local synthesis remains unclear. Here we show that the absence of locally synthesized complement component C3 is capable of modulating the rejection of renal allografts in vivo and regulating T-cell responses in vivo and in vitro. The results indicate that improved success in kidney transplantation could come from therapeutic manipulation of innate immunity in concert with T cell directed immunosuppression.

Acute Disease↗
PubMed1997

Complement factor C3 deposition and serum resistance in isogenic capsule and lipooligosaccharide sialic acid mutants of serogroup B Neisseria meningitidis.

Serogroup B meningococci express sialic acids on their surfaces as a modification of the lipooligosaccharide (LOS) and as capsular material consisting of alpha2,8-linked sialic acid homopolymers. The aim of this study was to elucidate the impact of each sialic acid component on the deposition of complement factor C3 and serum resistance. For this purpose, we used isogenic mutants deficient in capsule expression (a polysialyltransferase mutant) or sialylation of the LOS (a galE mutant) or both (a mutant with a deletion of the cps gene locus). Bactericidal assays using 40% normal human serum (NHS) demonstrated that both the capsule and LOS sialic acid are indispensable for serum resistance. By immunoblotting with monoclonal antibody MAb755 that is specific for the C3 alpha-chain, we were able to demonstrate that C3 from 40% NHS was covalently linked to the surface structures of meningococci as C3b and iC3b, irrespective of the surface sialic acid compounds. However, C3b linkage was more pronounced and occurred on a larger number of target molecules in galE mutants with nonsialylated LOS than in meningococci with wild-type LOS, irrespective of the capsule phenotype. C3b deposition was caused by both the classical pathway (CP) and the alternative pathway of complement activation. Use of 10% NHS revealed that at low serum concentrations, C3 deposition occurred via the CP and was detected primarily on nonsialylated-LOS galE mutants, irrespective of the capsular phenotype. Accordingly, immunoglobulin M (IgM) binding to meningococci from heat-inactivated NHS was demonstrated only in both encapsulated and unencapsulated galE mutants. In contrast, inhibition of IgA binding required both encapsulation and LOS sialylation. We conclude that serum resistance in wild-type serogroup B meningococci can only be partly explained by an alteration of the C3b linkage pattern, which seems to depend primarily on the presence of wild-type LOS, since a serum-resistant phenotype also requires capsule expression.

Bacterial Capsules↗
PubMed2000

Interleukin-1beta induces complement component C3 and IL-6 production at the basolateral and apical membranes in a human intestinal epithelial cell line.

In previous studies, stimulation of cultured enterocytes with IL-1beta resulted in production of IL-6 and complement component C3. The cellular mechanisms of these responses in the enterocyte are not fully understood. We tested the hypothesis that IL-1beta-induced C3 and IL-6 production is differentially regulated at the apical and basolateral membranes of the enterocyte. Caco-2 cells (a transformed human colonic carcinoma cell line) were grown in a 2-chamber system to full differentiation. The cells were treated with IL-1beta either at the apical or basolateral membrane, and C3 and IL-6 mRNA levels and release of C3 and IL-6 into the apical and basal chambers were determined. The release of C3 was greatest into the basal chamber regardless of whether the cells were stimulated at the apical or basolateral membrane. In contrast, the production of IL-6 was greatest at the cell membrane that was stimulated with IL-1beta. Stimulation of the Caco-2 cells with IL-1beta resulted in increased mRNA levels for C3 and IL-6 with no major differences noted when the cells were treated at the apical or basolateral membrane. The results suggest that enterocyte production and release of at least some acute phase proteins and cytokines are differentially regulated at the apical and basolateral membrane of the enterocyte after stimulation with IL-1beta.

Acute-Phase Reaction↗