The recent observation that a heat labile human immunoglobulin, IgE , could mediate the release of both histamine and SRS-Aᵐᵒⁿᵏᵉʸ from primate lung slices (Ishizaka et al., 1969), prompted a re-examination of the biologic activity of rat heat labile homocytotropic antibody.
Source: wiktionary