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Measuring the 50% Haemolytic Complement (CH50) Activity of Serum
08:26

Measuring the 50% Haemolytic Complement (CH50) Activity of Serum

Published on: March 30, 2010

Formation of the membrane attack complex of complement (MAC) on erythrocytes from monocyte-produced terminal

G Hetland, E Johnson, T Eskeland

    Scandinavian Journal of Immunology
    |June 1, 1987
    PubMed

    By using antibodies against C5, C6, C7, C8, and C9, we found that terminal complement components were deposited on IgM-coated sheep erythrocytes (EIgM) kept in serum-free endotoxin-stimulated monocyte cultures for 24 or 48 h. Monoclonal antibodies revealed C9 neoantigens on the EIgM. There was no specific binding of an anti-S protein antibody, which reacts with the SC5b-9 complex, to the EIgM. Controls were native sheep erythrocytes (E) treated similarly which, in contrast to EIgM, do not activate the classical pathway of complement. Cycloheximide (1.0 microgram/ml) in the cell cultures resulted in no specific binding of the anti-C9 antibodies to EIgM. A fraction of the EIgM was lysed during incubation with the monocytes. We conclude that the monocytes secrete C5, C6, C7, C8, and C9, which form the membrane attack complex of complement (C5b-9) on the EIgM.

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