CHARACTERIZATION OF FC-RECEPTORS FOR IGE ON HUMAN ALVEOLAR MACROPHAGES

  • 1 January 1982
    • journal article
    • research article
    • Vol. 49  (2) , 364-370
Abstract
Human alveolar macrophages (aM.vphi.) isolated from lung lavages performed during bronchoscopy and after surgical removal of pulmonary lobes were analyzed for Fc receptors for IgE (Fc.epsilon.R) and IgG (Fc.gamma.R) by rosette assays. A mean .+-. SD of 8.0 .+-. 2.6% of aM.vphi. formed rosettes with fixed ox erythrocytes coated with an IgE myeloma protein (Eo''-IgE). The Eo''-IgE rosettes were inhibited by 2 IgE myeloma proteins and by IgE Fc fragments but not by myeloma proteins of the other Ig classes or by IgE denatured by heating or reduction and alkylation. Fresh ox erythrocytes sensitized with rabbit IgG antibodies (EoA) formed rosettes with 64.1 .+-. 20.3% of the aM.vphi.. Peripheral blood monocytes formed 10.6 .+-. 1.2% Eo''-IgE and 90.2 .+-. 6.0% EoA rosettes. Incubation of the aM.vphi. with a goat antiserum to human lymphocyte Fc.epsilon.R inhibited Eo''-IgE rosette formation on aM.vphi. by 80% but did not affect the percentage of EoA rosettes. The antiserum also inhibited Eo''-IgE rosettes formed by peripheral blood monocytes and cultured macrophage-like [human lymphoma] U937 cells but not those formed by basophilic granulocytes obtained from a patient with chronic myelogenous leukemia. There was no relationship between age, sex, diagnosis or smoking history of the patients and the percentage of aM.vphi. forming Eo''-IgE rosettes. A subpopulation of human aM.vphi. bear Fc.epsilon.R that share antigenic determinants with Fc.epsilon.R on lymphocytes and monocytes. Fc.epsilon.R (+) aM.vphi. may play an important role in allergic and inflammatory pulmonary diseases by inducing the release of mediators of inflammation after interaction with IgE immune complexes.