Abstract
Minor elevation of the concentration of the C3b inactivator (KAF) in whole serum (by 15-25%) markedly inhibits the capacity of the serum to support complement activation by inulin, aggregated IgG and by low concentrations of CVF. However, there was no effect when large concentrations of CVF were used nor was the spontaneous ageing of C3 slowed by increased KAF concentrations. These findings show that the activity of the C3b feedback cycle can be reduced by raising the KAF concentration above physiological levels. This finding may provide a mechanism for damping down complement activation locally in vivo. It seems that the spontaneous ageing of C3 in vitro does not involve a KAF-inhibitable step and therefore cannot be involved to explain the 'C3 tickover' in vitro.
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Selected References
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- Abramson N., Alper C. A., Lachmann P. J., Rosen F. S., Jandl J. H. Deficiency of C3 inactivator in man. J Immunol. 1971 Jul;107(1):19–27. [PubMed] [Google Scholar]
- Alper C. A., Rosen F. S., Lachmann P. J. Inactivator of the third component of complement as an inhibitor in the properdin pathway. Proc Natl Acad Sci U S A. 1972 Oct;69(10):2910–2913. doi: 10.1073/pnas.69.10.2910. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ballow M., Cochrane C. G. Two anticomplementary factors in cobra venom: hemolysis of guinea pig erythrocytes by one of them. J Immunol. 1969 Nov;103(5):944–952. [PubMed] [Google Scholar]
- LAURELL C. B. ANTIGEN-ANTIBODY CROSSED ELECTROPHORESIS. Anal Biochem. 1965 Feb;10:358–361. doi: 10.1016/0003-2697(65)90278-2. [DOI] [PubMed] [Google Scholar]
- Lachmann P. J., Müller-Eberhard H. J. The demonstration in human serum of "conglutinogen-activating factor" and its effect on the third component of complement. J Immunol. 1968 Apr;100(4):691–698. [PubMed] [Google Scholar]
- Lachmann P. J., Nicol P., Aston W. P. Further studies on the C3b inactivator or conglutinogen activating factor (KAF). Immunochemistry. 1973 Oct;10(10):695–700. doi: 10.1016/0019-2791(73)90213-9. [DOI] [PubMed] [Google Scholar]
- Lachmann P. J., Nicol P. Reaction mechanism of the alternative pathway of complement fixation. Lancet. 1973 Mar 3;1(7801):465–467. doi: 10.1016/s0140-6736(73)91886-2. [DOI] [PubMed] [Google Scholar]
- Müller-Eberhard H. J., Götze O. C3 proactivator convertase and its mode of action. J Exp Med. 1972 Apr 1;135(4):1003–1008. doi: 10.1084/jem.135.4.1003. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nicholson A., Brade V., Lee G. D., Shin H. S., Mayer M. M. Kinetic studies of the formation of the properdin system enzymes on zymosan: evidence that nascent C3b controls the rate of assembly. J Immunol. 1974 Mar;112(3):1115–1123. [PubMed] [Google Scholar]
- Nicol P. A., Lachmann P. J. The alternate pathway of complement activation. The role of C3 and its inactivator (KAF). Immunology. 1973 Feb;24(2):259–275. [PMC free article] [PubMed] [Google Scholar]