Augmentation of IgE receptor expression and IgE receptor-mediated phagocytosis of rat bone marrow-derived macrophages by murine interferons.
Receptors for IgE (Fc epsilon R) on rat bone marrow-derived macrophages (BMDM phi) were demonstrated by a rosette assay employing trinitrophenyl-coated ox erythrocytes (EoTNP) sensitized with mouse IgE anti-dinitrophenyl monoclonal antibody (EoTNP-IgE). Virtually all BMDM phi emerging from bone marrow cells cultured for 1 week in the presence of mouse L929 cell supernatant, with partially purified murine CSF-1 or recombinant murine GM-CSF, formed IgE rosettes. To study the effect of interferons (IFNs) on Fc epsilon R expression, 1-week-old rat BMDM phi were incubated with murine recombinant IFN-gamma, purified IFN-alpha or IFN-beta, and were tested for their capacity to bind and ingest EoTNP sensitized suboptimally with IgE. A marked increase in the percentage of cells forming IgE rosettes or phagocytosing EoTNP-IgE was noted after 8-72 hr incubation of BMDM phi with 0.1-1000 U/ml of IFNs. At similar concentrations IFN-gamma and IFN-beta triggered EoTNP-IgE binding or ingestion more efficiently than IFN-alpha. The enhancing effect was blocked by the respective anti-IFN antibodies, cycloheximide or actinomycin D but not by mitomycin C. The IgE rosette formation and IgE-mediated phagocytosis were dose-dependently inhibited by native rat IgE but not by heat-denaturated IgE myeloma protein IR162 or monomeric rabbit IgG. Our results demonstrate that rat BMDM phi express constitutively Fc epsilon R, and that murine IFNs augment Fc epsilon R-mediated binding and ingestion in a time- and dose-dependent manner. This effect probably reflects an increase in the number of Fc epsilon R per cell, as a result of de novo synthesis of Fc epsilon R.
D000818:Animals; D000963:Antimetabolites / Q000494:pharmacology; D001853:Bone Marrow / Q000276:immunology*; D004306:Dose-Response Relationship, Immunologic; D007372:Interferons / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D010587:Phagocytosis; D051381:Rats; D011917:Rats, Inbred Lew; D011961:Receptors, Fc / Q000032:analysis*; D017455:Receptors, IgE; D012397:Rosette Formation; D014302:Trinitrobenzenesulfonic Acid / Q000276:immunology
D000963:Antimetabolites; D011961:Receptors, Fc; D017455:Receptors, IgE; D014302:Trinitrobenzenesulfonic Acid; D007372:Interferons