Noncytotoxic IgE-Mediated Release of Histamine and Serotonin from Murine Mastocytoma Cells

Abstract

Cultured murine mastocytoma (AB-CBF₁-MCT-1) cells were stimulated to release endogenous or incorporated histamine or serotonin by an IgE-mediated mechanism without loss of viability. Stimulation was achieved by incubation of the cells with rat IgE—anti-IgE, rat IgE—anti-light chain, fluoresceinated rat IgE—anti-fluorescein, IgE-enriched mouse anti-ovalbumin-ovalbumin, or covalently linked dimers of rat IgE, at doses similar to those optimal for normal peritoneal mast cells. Active cell metabolism and Ca⁺⁺ were required to obtain release. Despite the latter, no dose of the calcium ionophore, A23187, could be found which caused release without concomitant cytotoxicity. Phosphatidylserine did not enhance release.