Inhibitory Effects of Certain Avian and Mammalian Antisera in Specific Complement-Fixation Systems

Abstract

The results of quantitative studies of the inhibitory effect of non-complement-fixing antipullorum avian and antipneumococcus horse sera on fixation of complement by homologous rabbit antisera and antigen have been described. These data have indicated that the degree of inhibition is dependent not only upon the relative antibody content of the antisera of the two species concerned but also upon the quantity of antigen present. The possible application of the inhibition reaction, indirect complement-fixation test, in the assay of antibody content has been discussed and a tentative method of titrating this inhibitory activity outlined in which the sensitivity is adjusted to a level approximately comparable to that of the direct complement-fixation test.