Heterogeneity of guinea-pig homocytotropic antibodies.

It is suggested that guinea-pigs produce three different homocytotropic antibodies that can be distinguished by their physicochemical and biological properties. One has the properties of an IgG antibody, is heat and mercaptoethanol resistant and persists in the passively sensitized skin for not more than 72 hours. The other has the properties of an IgE antibody, is heat and mercaptoethanol labile and persists in the passively sensitized skin for at least 20 days. The third antibody is heat stable and mercaptoethanol labile and persists in the passively sensitized skin for more than 72 hours but less than 1 week. This antibody was partially separated from γ1 antibody by chromatography on DEAE cellulose and may represent a distinct segment of the γ1 antibody population. All three antibodies were able to sensitize guinea-pig mast cells and cause degranulation of these cells on reaction with antigen. Antihistamines produced complete inhibition of PCA reactions induced with all three types of antibodies but were much less efficient in inhibition PCA reactions induced with γ1 antibody obtained from hyperimmune serum.