title: Regulation of Fc receptors for IgG on cultured rat mesangial cells.
abstract: Localization of immune complexes (IC) to the mesangium may contribute to glomerular disease. Recently, we and others characterized Fc receptors (Fc gamma R) for IgG-IC on mesangial cells (MC). This study examines regulation of Fc gamma R by cAMP, interferon gamma (IFN-gamma) and by macrophage colony stimulating factor (CSF-1), an agent controlling Fc gamma R in leukocytes and generated by MC. Preincubation of MC (3rd to 6th subculture) with CSF-1, db-cAMP or IFN-gamma for two to 48 hours resulted in a time dependent (maximal 24 to 48 hrs) two- to threefold increase of specific [125I] IgG-IC binding to MC at 4 degrees C. The increase of Fc receptors induced by CSF-1, db-cAMP or IFN-gamma was confirmed by enhanced binding of the monoclonal anti-Fc receptor antibody 2.4G2 to MC. Uptake of IgG-IC at 37 degrees C was also enhanced in MC pretreated with CSF-1, db-cAMP or IFN-gamma. This indicates that the increase in binding for IgG-IC is associated with functional receptors. Immunoprecipitation of extracts of [125I] surface labeled MC with polyclonal anti-Fc gamma R-Ab followed by SDS-PAGE also showed increased amounts of [125I] Fc gamma R protein after pretreatment with CSF-1, db-cAMP or IFN-gamma. The pretreatment also enhanced staining of MC with anti-Fc gamma R-Ab by immunogold-silver enhancement technique. We conclude that MC express Fc gamma R for IgG-IC that can be regulated by CSF-1, cAMP and IFN-gamma, factors that may be important in glomerular immune injury.
authors.affiliation: Department of Medicine, Albert Einstein College of Medicine, Bronx, New York.
authors.forename: A
authors.initials: A
authors.lastname: Santiago
authors.forename: T
authors.initials: T
authors.lastname: Mori
authors.forename: J
authors.initials: J
authors.lastname: Satriano
authors.forename: D
authors.initials: D
authors.lastname: Schlondorff
mesh_terms: D000818:Animals; D000936:Antigen-Antibody Complex / Q000276:immunology*; D001666:Binding Sites, Antibody / Q000276:immunology; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000502:physiology*; D005920:Glomerular Mesangium / Q000166:cytology / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology*; D007371:Interferon-gamma / Q000502:physiology*; D016173:Macrophage Colony-Stimulating Factor / Q000502:physiology*; D008297:Male; D011233:Precipitin Tests; D051381:Rats; D011919:Rats, Inbred Strains; D011961:Receptors, Fc / Q000276:immunology*; D011994:Recombinant Proteins
chemical_list: D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D011961:Receptors, Fc; D011994:Recombinant Proteins; D016173:Macrophage Colony-Stimulating Factor; D007371:Interferon-gamma; D000242:Cyclic AMP