Sandwich enzyme-linked immunosorbent assays for the quantification of the C4 isotypes (C4A and C4B) in human plasma

Chrispeels, J.; Bank, Stephanie; Rittner, Christian; Bitter‐Suermann, D.

doi:10.1016/0022-1759(89)90071-9

Cited by 20 publications

(11 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The plasma or serum protein levels of total C4 vary between 100 and 1000 mg/L among different individuals, as do the relative quantities of C4A and C4B proteins. Although this phenomenon has been observed over a decade ago (5)(6)(7)(8)(9)(10)(11)(12)(13)(14), the molecular genetic basis for the qualitative and quantitative variations of human complement C4 was often accounted for inaccurately. Until recently, the sophistication of human C4 genetics has not been fully appreciated.…”

mentioning

confidence: 99%

Diversity in Intrinsic Strengths of the Human Complement System: Serum C4 Protein Concentrations Correlate withC4Gene Size and Polygenic Variations, Hemolytic Activities, and Body Mass Index

Yang

Chung

Zhou

et al. 2003

The Journal of Immunology

114

110

View full text Add to dashboard Cite

Among the genes and proteins of the human immune system, complement component C4 is extraordinary in its frequent germline variation in the size and number of genes. Definitive genotypic and phenotypic analyses were performed on a central European population to determine the C4 polygenic and gene size variations and their relationships with serum C4A and C4B protein concentrations and hemolytic activities. In a study population of 128 healthy subjects, the number of C4 genes present in a diploid genome varied between two to five, and 77.4% of the C4 genes belonged to the long form that contains the endogenous retrovirus HERV-K(C4). Intriguingly, higher C4 serum protein levels and higher C4 hemolytic activities were often detected in subjects with short C4 genes than those with long genes only, suggesting a negative epistatic effect of HERV-K(C4) on the expression of C4 proteins. Also, the body mass index appeared to affect the C4 serum levels, particularly in the individuals with medium or high C4 gene dosages, a phenomenon that was dissimilar in several aspects from the established correlation between body mass index and serum C3. As expected, there were strong, positive correlations between total C4 gene dosage and serum C4 protein concentrations, and between serum C4 protein concentrations and C4 hemolytic activities. There were also good correlations between the number of long genes with serum levels of C4A, and the number of short genes with serum levels of C4B. Thus, the polygenic and gene size variations of C4A and C4B contribute to the quantitative traits of C4 with a wide range of serum protein levels and hemolytic activities, and consequently the power of the innate defense system.

show abstract

mentioning

confidence: 99%

Diversity in Intrinsic Strengths of the Human Complement System: Serum C4 Protein Concentrations Correlate withC4Gene Size and Polygenic Variations, Hemolytic Activities, and Body Mass Index

Yang

Chung

Zhou

et al. 2003

The Journal of Immunology

114

110

View full text Add to dashboard Cite

show abstract

“…This concor dance can be explained on the assumptions that the ratio of C4A to C4B is first and fore most determined by the number of ex pressed genes. The reliability of C4 protein concentration should be greatly improved by the availability of an isotype-specific ELISA using monoclonal anti-C4A and anti-C4B antibodies [22], Greater deviations from the postulated values can hint at several causes. Responsible for such deviation could be, for instance, functional consumption of one of the isotypes, separate or differentiated regu lation of the two genes as Miura et al [23] showed for transfected C4 genes, or func tionally aberrant gene products, as C4A6 [24,25], or the presence of homoduplicated C4 genes expressing the identical allotype [26].…”

Section: Discussionmentioning

confidence: 99%

Rapid and Standardized Quantitation of Hemolytic Activity of the Fourth Component of Human Complement

Kaufmann¹,

Kytzia²,

Rittner³

1990

Complement Inflamm

Self Cite

View full text Add to dashboard Cite

Based on a method that uses the fourth component of complement (C4)-defi-cient guinea pig serum to quantify the hemolytic activity of C4, we developed an assay that allows the processing of a large number of individual samples with high reproducibility. In contrast to the conventional procedure using titration curves of each sample to be determined, we can show that a single appropriate dilution of the sample allows accurate quantitation of hemolytic activity. The reliability of the procedure is demonstrated using either C4A- or C4B- deficient and normal individual samples.

show abstract

“…These followed standard methods for BF [7] and C2 -for haemolysis see Alper [8], for Western blot ting Uring-Lambert et al [9], -as well as for C4 immunofixation and haemolytic overlay with neur aminidase and carboxypeptidase B treated samples [10,11], Western blots were developed with mono clonal antibodies [12] against C4A [Mauff et al, unpubl] and C4B [13] (both obtainable from Biotest AG, Offenbach, FRG). The biostatistical estimation of non-expressed C4 alleles in hemizygous or partly C4-deficient individuals was based on quantitative reading of electrophoretic patterns [14], as also used for the evaluation of C4 alpha chain determinations [15].…”

Section: Mhc Class III Determinationsmentioning

confidence: 99%

Association of Major Histocompatibility Complex Class III Complement Components C2, BF, and C4 with Brazilian Paracoccidioidomycosis

Messias¹,

Reis²,

Brenden³

et al. 1991

Complement Inflamm

View full text Add to dashboard Cite

A genetic influence of the major histocompatibility complex (MHC) on the susceptibility and the development of the different clinical forms of paracoccidioidomycosis (PCM) has been postulated. In the present investigation allotypes of MHC-coded class III gene products (complement components C2, BF, C4A, and B) were determined in 69 Brazilian PCM patients and 225 healthy control individuals matched for ethnic and geographic origin. The frequency of the non-expressed C4B allele (C4B*Q0) was significantly elevated in comparison to the controls (p < 0.01; Fisher’s exact test). Three out of 69 patients had a complete C4B deficiency as against 2 among 223 control individuals. The C4A *Q0 allele was also more frequent in the patients. Other C4 alleles were not seen to differ between the two groups. The analysis of BF allotypes showed a non-significant predominance of the rarer allele BF*S07 in the patients, whereas no difference in the distribution of C2 alleles was seen. The data on MHC class III association may support the hypothesis of immune response modulation in PCM and suggest a functional genetic role of complement action against the fungus and in the outcome of PCM infection. We conclude that MHC class III products, especially C4B*Q0, are associated with chronic uni- or multifocal PCM and may influence the course of the infection.

show abstract

Sandwich enzyme-linked immunosorbent assays for the quantification of the C4 isotypes (C4A and C4B) in human plasma

Cited by 20 publications

References 21 publications

Diversity in Intrinsic Strengths of the Human Complement System: Serum C4 Protein Concentrations Correlate withC4Gene Size and Polygenic Variations, Hemolytic Activities, and Body Mass Index

Diversity in Intrinsic Strengths of the Human Complement System: Serum C4 Protein Concentrations Correlate withC4Gene Size and Polygenic Variations, Hemolytic Activities, and Body Mass Index

Rapid and Standardized Quantitation of Hemolytic Activity of the Fourth Component of Human Complement

Association of Major Histocompatibility Complex Class III Complement Components C2, BF, and C4 with Brazilian Paracoccidioidomycosis

Contact Info

Product

Resources

About