Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Complement C3c”

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 163 records · Page 9Linked to original sources
PubMedDate not supplied

Prevalence of circulating immunecomplexes and variations of complement fractions in HBV, HDV and HCV infections: statistical analysis and clinical correlations.

Increased levels of circulating immunecomplexes (CIC) have been demonstrated in the serum of patients with HBV infection and HDV superinfection. This finding appears to be correlated to the disease's activity. In this report serum levels of two fractions of CIC (CIC-Clq and CIC-C3d) were evaluated by ELISA method in a sample of 110 subjects with hepatitis infection (HBV, HCV, HDV). Reference values were obtained in a group of 45 healthy subjects (blood donors). Both the CIC fractions were increased in the patients with HCV infection. The most significant increase for both CIC-C1q and CIC-C3d was found in the cirrhotic patients. The complement fractions C3c and C4 were determined in the serum of these patients to investigate a potential pathogenic role of such immunecomplexes. C3c and C4 fractions showed a significant decrease only in the cirrhotic patients, without correlation with the viral agent. Serum levels of C1q complement fraction were not significantly decreased, thus excluding an impaired synthesis of complement fractions. No significant correlation was found between CIC and C3c and C4 fractions in patients with increased levels of CIC, except a slightly significant correlation between reduction of C3c and increase of CIC-C1q. These data suggest a pathogenic action of immunecomplexes in the course of HCV, particularly in the cirrhotic stage.

Adult↗
PubMed1985

The quantitation of C3d by routine methods after the direct absorption of human plasma with anti-C3c.

The immunological methods for quantitating C3d in plasma require first the removal of less fragmented intermediates as well as the intact C3. We describe an alternative method for the quantitation of C3d in human plasma. The components which should be removed are absorbed (precipitated) directly in the plasma by a specific anti-C3c antiserum. It is then possible to determine the concentration of C3d by routine immunological methods.

Antibodies↗
PubMed1983

Quantitative quality control of antiglobulin reagents.

Double antibody radioimmunoassays have been developed for the quantification of anti-IgG, anti-C3, anti-C3c, anti-C3d and anti-C4 antibodies and for the determination of their binding constants. Assays were undertaken on 53 polyspecific antiglobulin reagents obtained from a variety of commercial and public sources. Concentrations of anti-IgG varied from 1.2 to 12.8 micrograms/ml in commercial products and from 0.4 to 6.0 micrograms/ml in public products. Concentrations of anti-C3 and anti-C3c varied from 0.1 to 1.0 micrograms/ml in most commercial products but in public products concentrations varied by more than 100-fold from 0.02 to 6.5 micrograms/ml. Concentrations of anti-C3d varied from 0.05 to 0.7 micrograms/ml in most commercial products and from less than 0.01 to 1.3 micrograms/ml in public products. Concentrations of anti-C4 varied from less than 0.01 to 0.18 micrograms/ml in commercial products and from less than 0.01 to 0.08 micrograms/ml in public products. Mean binding constants for commercial products were: anti-IgG 6.6 x 10(9) l/mol, anti-C3 4.6 x 10(9) l/mol, anti-C3c 5.3 x 10(9) l/mol, anti-C3d 0.4 x 10(9) l/mol and anti-C4 4.9 x 10(9) l/mol. Relationships were found between results obtained in quantitative assays of specific antibodies and independently performed serological assessments of potency. Anti-IgG was present in suboptimal concentrations for agglutination in several public products and anti-C3 and anti-C3c were in suboptimal concentrations for agglutination in many public and commercial products.

Antibodies, Anti-Idiotypic↗
PubMed1982

C3c and C3d fragments of human C3 bind myeloma IgG1 and IgG3 proteins.

Eight human myeloma proteins, two of each IgG subclass, were studied for binding to solid-phase C3c and C3d by the ELISA technique. Myeloma IgG1 kappa, IgG1 lambda, IgG3 kappa and IgG3 lambda proteins bound to C3c and C3d, while two IgG2 kappa, and two IgG4 kappa proteins failed to show significant binding affinity. The results suggest that like C1q, the stable binding sites of C3, located on the C3c and C3d parts of the molecule, have affinity for IgG subclasses 1 and 3.

Animals↗
PubMed1991

Computer imaging analysis of the correlation between intensities of glomerular immune-deposits and histopathology in patients with IgA nephropathy.

The relationship between the intensities of IgA, C3c, and C9 deposition in renal glomeruli and the severity of histopathologic injuries in patients with IgA nephropathy was examined using Microscope-Photometer 01K and a computer. Percentages of glomerular adhesion to Bowman's capsules, crescent formation, and glomerular sclerosis were calculated in the renal specimens. There was a significant correlation between the intensity of each C3c and C9 deposition in glomeruli and the degree of glomerular adhesion to Bowman's capsules and crescent formation in patients with IgA nephropathy. There was no significant correlation between the intensity of C3c or C9 deposition in glomeruli and the degree of glomerular sclerosis. No relationship was found between the intensity of IgA deposition in glomeruli and the degree of histopathologic injuries. The patients with negative or trace amounts of glomerular C3c deposits showed less severe glomerular injuries. Thus, the intensity of C3c and C9 deposition in glomeruli appears to be one of the critical factors responsible for the active progression of glomerular inflammatory process in patients with IgA nephropathy.

Complement C3c↗
PubMed1994

A possible role for autoantibodies in left ventricular hypertrophy.

The purpose of the study was to investigate the possible role of autoantibodies in the development and type of left-ventricular hypertrophy (LVH). Three groups of subjects were studied: (a) 15 patients with hypertrophic cardiomyopathy (HCM; 11 males, 4 females; mean age 50.0 +/- 16.3 years); (b) 15 patients with essential hypertension (10 males, 5 females; mean age 56.8 +/- 13.5 years) with normal renal function and serum electrolytes and (c) 15 male athletes (mean age 20.8 +/- 5.9 years). The control group consisted of 15 normal subjects with no sign of heart disease. The following indices of cardiac performance were determined by means of echocardiography: end-diastolic and end-systolic diameters, interventricular septum thickness, left-ventricular (LV) wall thickness, LV mass and LV mass index. The immunologic parameters studied included autoantibodies against (a) specific (anticardiac cell; ACA) and (b) nonspecific (antimitochondrial cell; AMA) autoantigens according to a conventional indirect immunofluorescence technique. (1) Higher values for LV mass and LV mass index were observed in HCM. (2) The incidence of specific and non-specific autoantibodies in hypertensive patients and in patients with HCM was significantly higher compared to athletes and controls. All ACA-positive individuals (5 with HCM, 3 with hypertension and 1 athlete) were AMA positive as well, while all ACA-negative individuals were also AMA negative. The ACA-positive individuals had higher C3c and C4 levels compared to the ACA-negative individuals. An autoantibody-mediated immunopathogenic role is discussed in the development and type of myocardial hypertrophy.

Adult↗
PubMed1984

[Normal values of IgA, IgM, IgG, C3c, C4, alpha 1-acid glycoprotein in blood from the umbilical cord of healthy newborn infants using laser-nephelometry. III: C3c, C4, alpha 1-acid glycoprotein].

The authors have determined, using the laser-nephelometric technique, the concentration of C3c, C4 and alpha 1-acid glycoprotein in the umbilical cord blood of normal newborns. The results obtained are sufficiently in agreement with literature data, even if there are some differences derived by methods and environmental factors.

Complement C3↗
PubMed1984

[Effects of the use of FRIGEN (AG-Ffm-HOECST) on the determination of blood levels of some proteins (IgA, IgM, IgG, C3c, C4) in cord blood of healthy newborn infants at term by laser nephelometry].

The purpose of this paper is to establishes the FRIGEN effects on the determination of IgA, IgM, IgG, C3c, C4 cord-blood levels, by means of laser-nephelometry. The results show substantial interferences only in the IgA levels, whereas the other on almost all proteins are not affected, the found interference can be due to the amount of IgA bound to B-lipoprotein, that are precipitated by FRIGEN.

Chlorofluorocarbons, Methane↗
PubMed1997

Mechanism of infiltration and activation of glomerular monocytes/macrophages in IgA nephropathy.

Glomerular deposits of fibrin-related antigens (FRA), C3c, membrane attack complex (MAC) were examined by the immunoperoxidase method on 176 renal biopsy specimens from 120 cases with IgA nephropathy including 56 cases with sequential biopsies. On 47 sets of repeated renal biopsy specimens, the glomerular infiltration of the following immune cells was examined by the indirect immunoperoxidase method; immune cells positive for C3bi receptor (C3biR; CR3/CD11b, CR4/CD11c), HLADR antigen and several leukocyte surface markers (CD45R, CD3, CD15 and CD68). Twenty-four-hour urine protein (UP) at the renal biopsy was also evaluated. The glomerular deposition of FRA was inversely correlated with C3c/MAC deposition (p < 0.00001). Most cases (163 of 176) were classified into the following two types; type C with dominant deposition of C3c (97 cases) and type F with dominant deposition of FRA (66 cases), except for 13 cases with equivalent deposits of C3c and FRA (7 cases, type B) and without C3 or FRA deposits (6 cases, type O). In 56 rebiopsied cases, apparent conversion from type F or C into the other was observed only in one case though a few cases in type C lost or reduced C3c deposition to an equivocal type at the follow-up biopsy, which were included in type C', an expanded category of type C. In the whole cases, the glomerular infiltration of immune cells was significantly correlated with FRA deposition (p < 0.0002) but not with C3c. Glomerular CD11c+ cells were significantly correlated with C3c deposition in type C' (p < 0.0001), but not in type F. Glomerular HLADR positive immune cells were significantly correlated with glomerular CD3+ T cells in type F (p < 0.001), but not in type C'. In type C', UP was significantly correlated with glomerular CD11c+ cells (p < 0.0001) but not with CD 15+ or HLADR+ cells. On the other hand, in type F, UP was significantly correlated with CD 15+ and HLADR+ cells (p < 0.001) but not with CD11c+ cells. These results suggested that there are multiple pathways in inducing glomerular infiltration of immune cells in IgA nephropathy. In type C, local activation of complements might primarily induce immune cell infiltration through C3biR and these C3biR+ cells are involved in inducing proteinuria. On the other hand, in type F, in which complement activation is weak, immune cells might infiltrate directly through their Fc receptor or MHC class II antigens, and might be activated by T-cell/macrophage interaction to induce proteinuria.

Adult↗
PubMed1987

Immunoelectron microscopic study of glomerular lesions using a postembedding method with a protein A-gold complex.

Renal biopsy tissue from 33 children with various glomerular diseases has been investigated by electron microscopy using a postembedding immunostaining technique with a protein A-gold complex in order to establish more precise correlations between immunopathologic and morphologic findings in glomeruli. This technique could detect immunoglobulins (IgG, IgA, and IgM), complement factor (C3c), and fibrinogen-related antigen. The immunoreactivity of these antigens was essentially confined to the mesangial, paramesangial, subendothelial, and subepithelial 'electron-dense deposits' in the glomeruli. Except for IgM and C3c in the case of glomerular sclerosis, the distribution of the mentioned factors was even in the electron-dense deposits, as could be shown by 'double-immunolabeling'. From the above-mentioned findings one can conclude that several of the localized factors are associated with the formation of electron-dense deposits, the ultrastructural hallmarks of glomerular disease.

Antigens↗
PubMed1982

Influence of time, temperature and coagulation on the measurement of C3, C3 split products and C4.

Quantitative and qualitative immunoelectrophoretic analyses of circulating C3, C3 split products and C4 were performed in matched EDTA plasma and serum obtained from 5 normal subjects and stored for up to 48 h at room temperature (18 degrees C-22 degrees C) and 4 degrees C. Fluctuations in apparent levels of C3 were greater in serum than plasma stored at room temperature, a fall in levels seen by 24 h being followed by a significant increase. By contrast, levels of C3 did not alter if stored at 4 degrees C. C4 levels in both EDTA plasma and serum remained unchanged for 24 h, a slight decrease being seen at 48 h. Levels of C4 remained constant if samples were stored at 4 degrees C. Crossed immunoelectrophoresis revealed a significant progressive decrease in C3 levels and a simultaneous increase in C3c occurring after 4 h in serum and 8 h in EDTA plasma, stored at room temperature. In studies conducted at 4 degrees C, similar but delayed fluctuations were seen. A progressive and significant increase in C3d levels was seen in both plasma and serum samples stored at room temperature, levels rising to 276% (plasma) and 308% (serum) of levels seen at zero time. At 4 degrees C marginal increases in C3d levels only were observed. These results suggest that in vitro degradation of C3 and C4 are readily facilitated by temperature, time and coagulation, and that conditions of collection and storage of samples must be optimized for the accurate definition of activation of the complement cascade.

Adult↗
PubMed1987

Host serum protein levels in cysts of human hydatidosis.

8 proteins (albumin, IgG, IgM, IgA, C3c, C4, orosomucoid and alpha 1 antitrypsin) were determined by laser immunonephelometry in hydatid cyst fluid from cysts and sera from 16 patients. The cystic level of albumin was 34.5 +/- SD 59.1 micrograms/ml (range 3.6-85); of IgG 12.9 +/- 18.7 micrograms/ml (1.9-75); of IgM 10.5 +/- 10.4 micrograms/ml (3-37); and of IgA 7.2 +/- 3.5 micrograms/ml (4-19.7). The 4 other proteins represented a smaller fraction: C3c, 0.9 +/- 0.6 micrograms/ml (0.5-2.5); C4, 1.3 +/- 0.9 micrograms/ml (0.5-3.5); orosomucoid, 2.8 +/- 2.3 micrograms/ml (1.4-9.2); and alpha 1-antitrypsin, 5 +/- 4.5 micrograms/ml (2-19). These 8 host proteins constituted 24.6 +/- 24.5% (2.4-76) of the total hydatid cyst fluid proteins (343.7 +/- 172.1 micrograms/ml, range 180-900). The albumin/IgG ration of 3 +/- 2.8 (0.4-10.8) in hydatid cyst fluid was more variable than that in sera, 2 +/- 0.5 (1.2-2.7).

Blood Proteins↗
PubMed1996

Clinical significance of the alterations of plasma prostaglandin E2 (PGE2) in severely burned patients.

Agar gel single diffusion and radio immunological analyses were employed to determine the levels of serum C3c, C4, IgA, IgM, IgG and plasma PGE2 in 24 severely burned patients. The results were compared with the development of postburn immunosuppression, severe infection and MOF. There were marked decreases in serum C3c, C4 and Ig, which were especially marked in patients with MOF. Furthermore, plasma PGE2 decreased markedly in patients with MOF and/or severe systemic infection. The results suggest that the decrease of deficiency in plasma PGE2 was closely related to the immunosuppression and the development of severe systemic infection and/or MOF, which supported the hypothesis that PGE2 might play a role in immunoprotection, but not immunosuppression, in burned patients.

Adolescent↗
PubMed1996

Immunological alterations in sera of persons living in areas with different air pollution.

The present study aimed to investigate immune parameters in sera of adult persons chronically exposed to different degrees of ambient air pollution. As related to air pollution derived from coal mining industry and coke plants, a significantly increased prevalence of cases with abnormally high serum levels of the immunoglobulins IgA and IgM as well as the complement component C3c was found as compared with a less polluted control area, indicating a higher stimulation of acute reactants in combination with a polyclonal immune response. These findings may be attributed to elevated concentrations of airborne particulates, suggesting that permanent exposure to increased levels of airborne particulates leads to chronic irritation of the airways in association with activation of the immune system, which may give rise to an enhanced risk for chronic airway diseases.

Air Pollutants↗
PubMed1983

Rapid turbidimetric determination of serum C3c and C4 by end point centrifugal analysis.

An end point turbidimetric method for the determination of C3c and C4 in serum using a centrifugal analyzer (Cobas Bio) is described. Several analytical factors were evaluated -pH, temperature, PEG and antibody concentration. Wide variations of temperature and pH did not significantly affect the turbidimetric reaction. A 20 g/L PEG concentration and 25-fold antiserum dilution were found satisfactory for the analysis. Precision of the assay was good and comparison with a RID method yielded an r value of 0.97. The procedure is simple and reliable.

Centrifugation↗
PubMed1991

Activation of rabbit C3: studies of the generation of cleavage products in vitro and of their metabolism in vivo.

The cleavage of purified, functionally active rabbit C3 by cobra venom factor and trypsin was analysed by reducing and non-reducing sodium dodecyl sulphate electrophoresis and autoradiography. The specific aim of the study was to compare these reactions to those that occur with human C3. Analysis showed that the pattern of breakdown was very similar to that for the human protein: while the beta-chain remained intact, there was step-wise degradation of the alpha-chain to form C3a, C3b, iC3b and C3c, all of which could be identified by gel analysis. The metabolic behaviour of three of these cleavage products, C3a, C3b and iC3b, was then examined in vivo using dual isotope techniques. Rabbits were studied simultaneously with 131I-C3 and 125I-labelled C3 breakdown products. Analysis of plasma and urine radioactivity for the subsequent 72 h showed that all three breakdown proteins had rapid rates of catabolism in vivo compared to the native molecule. Specifically, 93 and 98% of C3b and iC3b, respectively, were eliminated from the plasma compartment within 10 h of injection. C3a was completely eliminated within 10 h. By comparison, native C3 showed a half-life of 29 +/- 3 h (mean +/- SD) and a fractional catabolic rate of 4.30 +/- 0.75%/h. The data support the use of this species in studies of complement behaviour in models of human immune disease and further clarify the basis for changes in plasma C3 concentration that accompany active immune complex- and antibody-mediated activity, in vivo.

Animals↗
PubMed1984

Immunopathological correlation between mesangial C3d-deposition and C3d-fixing circulating immune complexes in lupus nephritis.

By a direct immunofluorescent technique, glomerular C3d deposition was examined in a total of 50 renal biopsy specimens from patients with lupus nephritis. C3d deposition was then compared with disease activity, glomerular IgG and C3c deposition, and the levels of circulating immune complexes (CIC) measured by a solid-phase anti-C3d assay. There was a good correlation between disease activity and the positivity of glomerular C3d deposits (P less than 0.001), as well as C3c deposits (P less than 0.001). Even in clinically inactive patients, a relatively high percentage (59%) of C3d deposits were positive compared with C3c deposits (17%). Mesangial C3d deposition correlated with clinical disease activity more significantly (P less than 0.005) than capillary wall C3d deposition (P less than 0.025). C3d deposits were detected in all of the 30 cases with positive C3c deposits, and moreover, in 15 of the 20 (75%) cases with negative C3c deposits. Glomerular IgG deposits were almost always associated with C3d deposits, both in mesangial areas and along capillary walls, with statistical significance (P less than 0.005, P less than 0.001, respectively). The serum levels of C3d-fixing immune complexes (IC) were significantly correlated with the positivity and intensity of mesangial C3d deposits. This study demonstrates glomerular deposition of C3d in patients with lupus nephritis and reveals a significant correlation between mesangial C3d deposition and disease activity.

Antigen-Antibody Complex↗
PubMed1983

Partial characterization of physiologically generated C3 components expressing C3d but not C3c epitopes.

Techniques for the quantification of C3d are shown to estimate the sum of 4 different plasma protein components possessing C3d but not C3c epitopes. All 4 components were C3-derived polypeptides as shown by activating serum containing 125I-labelled C3, isolating the anti-C3d reactive material in 14% PEG supernatant, followed by analysis on SDS-PAGE and autoradiography. Identical results were obtained by radiolabelling 14% PEG plasma supernatants followed by analysis of the anti-C3d reactive material. The components are referred to as d1, d1', d2 and d3 based on their relative electrophoretic mobilities (alpha 1, alpha 1, alpha 2 and alpha 2 respectively) judged by crossed immunoelectrophoresis. Their apparent molecular weights by SDS-PAGE were 129K (d1), 110K (d1'), 46K (d3) and 45K (d2). The possibility that one or more of the C3d containing components represented a complex of a C3 fragment with another plasma protein was investigated. The role of these components in the scheme of the physiological breakdown of C3 and the importance of the individual C3d components as indicators of complement activation in clinical materials is discussed. It is proposed that the 45K d2 component represents a final physiological breakdown product of C3 in human serum.

Antigen-Antibody Reactions↗