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 t...

beta thalassemia major patients receive repeated transfusions in order to compensate anemia and use desferal to remove iron overload. comparing immunoglobulins and complement components in the serum of these patients with normal range shows a significant increase (p<0.001) in igg, iga and igm and a decrease in c3c and c4. the regression analysis confirms a relation between the numbers of transf...

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 convertase...

Radioimmune assays were developed to assay the binding of complement components C1q, C1s and C4 to antibody aggregates and to cell-bound antibody. The binding of the components was compared with the haemolytic activity and with the capacity to form the C3 convertase activity in the presence of excess C2. The destruction of whole complement and of C4 activity is similar per 1,000 molecules of an...

background: the serum levels of c 3 , c4, and the total hemolytic activity of complement system (ch50) of patients ex­posed to mustard gas (mg) in the battlefield were measured in this study. methods: c3 and c4 were measured by single radial immunodifusion and ch50 was evaluated according to total hemolytic activ­ity of the serum. results:   the serum levels of c 3 showed a significant increase...

The role of complement in host resistance to infection with Trypanosoma lewisi was studied in normal, C4-deficient, and C3-depleted rats. Complement levels were measured in normal rats throughout the course of infection. A drastic reduction of total complement and C4 hemolytic activities occurred, and C3 levels measured immunochemically were decreased. Although total complement and C4 levels we...

The levels of complement C3 and C4 components were determined in non-indigenous (creoles) and indigenous (Warao) populations, the latter with an extremely high tuberculosis (TB) rate. Serum samples from 209 adults were studied and classified in 4 groups taking into account tuberculin skin tests (TST): (1) the group of Warao patients (58 positive for the TST, WP TST+ and 9 negative for the TST, ...

The aim of this study was to analyze the changes in complements C3 and C4 and C-reactive protein (CRP) in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), and to evaluate the role of these indices in the differential diagnosis of SLE and RA. The first 347 patients with SLE, 382 patients with RA and 66 patients with erythema nodosum were selected for the measuremen...

The fourth component of complement, C4, was isolated from bovine plasma in high yield, by using simple purification techniques. The protein, like human component C4, is a beta-globulin with a mol.wt. of about 200 000 and consists of three polypeptide chains, alpha, beta and gamma, with apparent mol. wts. of 98 000, 82 000 and 32 000 respectively. The chains of C4 have been separated by methods ...

Peripheral blood eosinophils from patients with eosinophilia and from healthy subjects were studied for surface immunoglobulins, receptors for the Fc region of IgG, complement receptors, and spontaneous rosette formation with sheep and mouse erythrocytes. Eosinophils were found to have receptors for complement and for aggregated IgG, and to have the same two types of complement receptors as do ...