Search results for "C4A"
showing 10 items of 20 documents
C4, BF, C3 Allele Distribution and Complement Activity in Healthy Aged People and Centenarians
1999
The aim of this study was to examine the complement system and the distribution of some human leukocyte antigen (HLA) class III alleles (C4, BF) in healthy aged people (77 centenarians and 89 elderly subjects). We have also studied the alleles of C3, a complement component genetically unrelated to HLA, the immunochemical levels of C4 and C3 and serum functional hemolytic activity for classical (CH50) and alternative (AP50) complement pathway. The levels of C3 and C4 and the CH50 and AP50 were found to be within the normal range. The frequencies of C3, BF, and C4A alleles were similar in the cohorts that have been studied. For C4B null allele (C4BQ0) a trend toward an increase in the older c…
C4A deficiency and nonresponse to hepatitis B vaccination
2002
Hepatitis B vaccination failure has been linked to the presence of certain human leukocyte antigen class II alleles. However, the functional background of these associations has remained unclear. Complement component C 4 is encoded within the major histocompatibility complex and is essential for classical pathway activation.Healthy individuals (n=4269) were vaccinated in a prospective trial with Engerix B. Nonresponse was classified as anti-HBs10 U/l after the last vaccination. Seventy-three nonresponders (NR) (1.7%) were identified. For comparison 53 responders (R) (anti-HBs10 IU/l) were drawn randomly from the same cohort. C4 allotyping was carried out by high-voltage agarose gel electrop…
Genetic control of immune response in carriers of the 8.1 ancestral haplotype: correlation with levels of IgG subclasses: its relevance in the pathog…
2007
Ancestral haplotype (AH) 8.1(HLA-A1, Cw7, B8, TNFAB*a2b3, TNFN*S, C2*C, Bf*s, C4A*Q0, C4B*1, DRB1*0301, DRB3*0101, DQA1*0501, DQB1*0201) seems to be associated with susceptibility to autoimmune diseases. Different mechanisms are probably involved in increasing autoimmunity, such as unbalanced cytokine production and the lack of C4A protein. So AH 8.1 modifies immune response in many ways. In this study we demonstrate that IgG2 serum levels were significantly lower in 8.1 AH carriers than in 8.1 AH non-carriers. On the contrary, as regards IgG1, IgG3, IgG4 serum levels, no significant differences were observed between the two groups. In AH 8.1 carriers low IgG2 levels might take to slower cl…
Characterization of non-expressed C4 genes in a case of complete C4 deficiency: identification of a novel point mutation leading to a premature stop …
1998
The genetic basis of complete C4 deficiency in a patient with SLE was investigated. Previous studies have demonstrated that this patient has two different major histocompatibility complex (MHC) haplotypes that each contain a major deletion and a non-expressed C4 gene. In the present study, non-expression of the C4 genes was explained by the finding of two distinct C4 gene mutations. A previously described two base pair insertion in exon 29 of the C4 gene was detected in the paternal MHC haplotype [HLA-A2, B40, SC00, DR6]. The maternal haplotype [HLA-A30, B18, F1C00, DR3] carried a C4 gene with a one base pair deletion in exon 20 generating a premature stop codon. This mutation was neither f…
Genetic control of immune response in carriers of ancestral haplotype 8.1: the study of chemotaxis.
2007
In all caucasian populations the association of an impressive number of autoimmune diseases with genes from the HLA-B8, DR3 hap- lotype that is part of the ancestral haplotype (AH) 8.1 HLA-A1, Cw7, B8, TNFAB∗a2b3, TNFN∗S, C2∗C, Bf∗s, C4A∗Q0, C4B∗1, DRB1∗0301, DRB3∗0101, DQA1∗0501, DQB1∗0201 has been reported by different research groups. This haplotype, which is more common in northern Europe, is also associated with a number of immune system dysfunctions in healthy subjects. Analyzing the data according to gender, some dysfunc- tions are observed in women but not in men, in agreement with the role of X-linked genes and/or estrogens in the development and progression of autoimmune diseases.…
Anaphylatoxin-like molecules generated during complement activation induce a dramatic enhancement of particle uptake in rainbow trout phagocytes.
2004
Here we have identified a serum fraction containing approximately 8-kDa molecules with an unexpected capacity to greatly enhance particle uptake in trout head kidney leukocytes (HKLs). This approximately 8-kDa particle-uptake enhancing fraction (PUEF-8) was purified from complement-activated serum by gel filtration chromatography. Mass spectrometric analysis and reactivity of anti-trout C3-1 and C4 antibodies, indicated the presence of C3a, C4a and C5a molecules in PUEF-8. Using a newly developed flow cytometric assay that measures the capacity of cells to ingest fluorescent beads, we showed that PUEF-8 induced a striking enhancement (344+/-50% higher than the PBS control value) in the numb…
C4 Alpha-Chain Reference Typing Report
1990
Previously it was shown that C4A and C4B alpha-chains after separation on SDS-PAGE can provide valuable information on presence and absence, as well as the number of C4A and C4B genes expressed in an individual. All samples submitted for C4 reference typing were also subjected to C4 alpha-chain separation; the results were included in the Final C4 Reference Typing List [Complement Inflamm 1990;7:193-212]. In addition, in selected cases with assumed 'reversed antigenicity', Western blots of C4 alpha-chains with monoclonal anti-C4A and B antibodies were obtained. As a result, subtypic differences of C4B allotypes were detected by the comparison of monoclonal antibodies 1217 and 1228.
Pathogenesis of autoimmune diseases associated with 8.1 ancestral haplotype: effect of multiple gene interactions.
2003
Genetic studies have shown that individuals with certain HLA alleles have a higher risk of specific autoimmune disease than those without these alleles. Particularly, the association in all Caucasian populations of an impressive number of autoimmune diseases with genes from the HLA-B8,DR3 haplotype that is part of the ancestral haplotype (AH) 8.1 HLA-A1, Cw7, B8, TNFAB*a2b3, TNFN*S, C2*C, Bf*s, C4A*Q0, C4B*1, DRB1*0301, DRB3*0101, DQA1*0501, DQB1*0201 has been reported by different research groups. This haplotype, the more common one in northern Europe, is also associated in healthy subjects with a number of immune system dysfunctions. It has been proposed that a small number of genes withi…
Effects of a Carob-Pod-Derived Sweetener on Glucose Metabolism
2018
Background: Patients with type 2 diabetes mellitus (T2DM) have a higher incidence of cardiovascular (CV) events. The ingestion of high-glycemic index (GI) diets, specially sweetened beverage consumption, has been associated with the development of T2DM and CV disease. Objective: We investigated the effects of the intake of a sweetened beverage, obtained from natural carbohydrates containing pinitol (PEB) compared to a sucrose-enriched beverage (SEB) in the context of impaired glucose tolerance (IGT) and diabetes. Methods: The study was divided in three different phases: (1) a discovery phase where the plasma proteomic profile was investigated by 2-DE (two-dimensional electrophoresis) follow…
Comparative study on biological activities of various anaphylatoxins (C4a, C3a, C5a)
1981
Several anaphylatoxic substances (human C3a, guinea pig C3a, human C4a, guinea pig C5a, and a synthetic C3a-related hexapeptide) were compared with regard to their ability to induce secretion of [3H] serotonin from guinea pig platelets. Functional identity of the C3a preparations, C4a, and the hexapeptide was demonstrated by the phenomenon of crossed desensitization. Whereas C3a of human and guinea pig origin proved to be qualitatively and quantitatively identical, C4a expressed only 3% of the activity of the C3 fragments on a molar basis. Investigations with goat anti-guinea pig C3a demonstrate that human and guinea pig C3a possess one antigenic determinant in common; however, this determi…