Functionally active complement proteins C6 and C7 detected in C6‐ and C7‐deficient individuals

• Published in: Clinical and experimental immunology Vol. 83; no. 3; pp. 430 - 437
• Main Authors: WÜRZNER, R., ORREN, A., POTTER, P., MORGAN, B. P., PONARD, D., SPÄTH, P., BRAI, M., SCHULZE, M., HAPPE, L., GÖTZE, O.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-03-1991; Blackwell
• Subjects: Antibodies, Monoclonal; Biological and medical sciences; Blood Bactericidal Activity - immunology; Complement Activation; Complement C6 - analysis; Complement C6 - deficiency; Complement C7 - analysis; Complement C7 - deficiency; Complement C9 - physiology; complement deficiency; Complement Hemolytic Activity Assay; Electrophoresis, Polyacrylamide Gel; Enzyme-Linked Immunosorbent Assay; Humans; Immunoblotting; Immunodeficiencies; Immunodeficiencies. Immunoglobulinopathies; Immunopathology; Medical sciences; Specimen Handling; Temperature; terminal complement complex; Zymosan; Human; Complement C6; Immunopathology; Complement C7; Immunoblotting assay; Quantization; Complement; Monoclonal antibody; Detection; Immune deficiency; ELISA assay
• ISSN: 0009-9104; 1365-2249
• DOI: 10.1111/j.1365-2249.1991.tb05656.x

SUMMARY
Two sensitive sandwich ELISAs based on monoclonal antibodies directed to native C6 and C7 allowed the detection and quantitation of these complement proteins in 20 out of 37 serum samples from individuals who had previously been classified as deficient in these proteins as assessed by immunochemical and/or functional assays. Furthermore, serum from four C6‐deficient and one combined C6‐/C7‐deficient individual showed an increase in the terminal complement complex (TCC) and a decrease in native C6 and C7 after complement activation as assayed by specific ELISAs. Despite their (incomplete) deficiencies, these individuals therefore possess functionally active terminal complement proteins with respect to their ability to generate the TCC. As these individuals have no history of a susceptibility to neisserial infections, even low concentrations of functionally active C6 and C7 may provide sufficient protection against those micro‐organisms whose destruction requires TCC formation.