The Serological Properties of Simple Substances. III. The Composition of Precipitates of Antibodies and Polyhaptenic Simple Substances; the Valence of Antibodies

Abstract

The antibody-antigen mole ratio of precipitates formed by interaction of antigens and homologous antisera provides information about the relative combining powers or “valences” of antigen and antibody molecules. For protein antigens it has been found by Heidelberger and co-workers and by other investigators that the antibody-antigen mole ratio is greater than unity, and increases from the antigen-excess region (where the values approach unity) through the equivalence zone to the antibody-excess region, the values for the last region being nearly twice those for the equivalence zone. These results, which show that the effective valence of the protein antigen molecules is greater than that of the antibody molecules, have been accounted for in a reasonable way by the framework theory and the postulate that antibodies which act as precipitins are bivalent. Since the mole ratio gives only the relative valences of antigen and antibody, and information about the valence of protein antigens is in general not at hand, these data do not directly provide information about the valence of the antibodies; but similar data for simple antigens of known structure should give this information. In this paper, the third in a series of studies of the serological properties of simple substances, we present and discuss the results of about 400 analyses of precipitates formed by antibodies and polyhaptenic substances.