Early and late pig IgG anti-DNP antibodies, having different capacities to precipitate DNP-serum albumin, were completed with this antigen at various antigen to antibody ratios, and the ability of resulting complexes to consume complement from pig, human and guinea-pig sera was examined. Complexes of all antibody types were shown to activate the various complement systems through th classical pathway and, with high doses of the complexes, also complexes, also through the alternative pathway. Most marked qualitative differences in complement consumption by complexes of different antibodies could be demonstrated with pig complement, whereas the assay using guinea-pig complement revealed largest differences between the consumption maxima. The complexes containing an early, precipitating anti-DNP antibody showed the strongest complement consuming effect as well as the strongest fixation of human C1, even in zone of antigen excess. A late, incompletely precipitating antibody was found to be extremely inefficient in the activation of the guinea-pig complement, while with human and pig complement, appreciable complement consumption was observed. The complexes containing a late, non-precipitating anti-DNP antibody showed a rlatively high complement consuming capacity particularly with the pig and guinea-pig complement.
ASJC Scopus subject areas