The existence, in several species, of two major types of homocytotropic antibodies has been recognized and reviewed previously (1). In the preceding paper (2) conditions were described for studying in vitro the antigen-induced release of histamine in the rat IgE and IgGa antibody-mediated systems. The present paper further characterizes the properties of the IgGa antibodymediated reaction and presents evidence that homologous IgGa and IgE antibodies utilize the same cellular receptors in the pathway leading to the release of histamine.
Materials and MethodsThe media, antigen, and antibody preparations used in this study were the same as those previously described (2). Except where specifically indicated, the conditions of the experiments were those found to yield optimum results in the previous study (2).