The Capacity of Human Immunoglobulin E to Mediate the Release of Histamine and Slow Reacting Substance of Anaphylaxis (SRS-A) from Monkey Lung

Abstract

Abstract Monkey lung fragments passively sensitized in vitro with human serum rich in IgE antibody released both histamine and slow reacting substance of anaphylaxis (SRS-A) upon challenge with specific allergen or anti-IgE. The sensitizing activity of the atopic serum was heat labile and was removed by treatment with an anti-IgE immunosorbent. In the reversed-type reactions, 7S anti-IgE and its F(ab′)2 fragments had comparable activity in mediating the release of both histamine and SRS-A, and Fab′ fragments did not release either mediator suggesting that bridging of two cellbound IgE molecules may be the initial step of the reaction. Monospecific antiserum against human IgG, IgM, IgA or IgD failed to release either mediator from sensitized tissue. Isolated E myeloma protein also sensitized monkey lung fragments for the release of both histamine and SRS-A by anti-IgE. It thus appears that immunoglobulin E sensitizes monkey lung fragments for the direct (antigen-induced) or reversed (anti-IgE-induced) release of both histamine and SRS-A.