title: Decrease of HLA-DR antigen expression by human monocytes during cultivation in absence of exogenous or endogenous interferon-gamma.
abstract: The kinetics of HLA-DR antigen expression by human peripheral blood monocytes during cultivation in vitro was studied. Immediately after separation by glass adherence, about 60% of monocytes expressed DR antigens as judged by indirect fluorescence staining with a monoclonal antibody (BL-DR/1). Monocytes carefully depleted of lymphocytes, gradually lost their DR antigens during cultivation in the absence of exogenous interferon-gamma (IFN-gamma). However, addition of a few lymphocytes to the adherent cells prevented the decrease of DR antigen expression. Furthermore, it was shown that doses as low as 1 IU/ml of IFN-gamma are sufficient to induce DR antigen expression by cultured monocytes. Experiments with cyclosporin A suggest that lymphocytes contaminating the monocyte preparations can produce spontaneously sufficient amounts of IFN-gamma for maintenance of the DR antigens on monocytes.
mesh_terms: D002478:Cells, Cultured; D003524:Cyclosporins / Q000494:pharmacology; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology / Q000494:pharmacology*; D007700:Kinetics; D009000:Monocytes / Q000187:drug effects / Q000276:immunology*
chemical_list: D003524:Cyclosporins; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D007371:Interferon-gamma