Differential effect of monoclonal anti-DR antibody on monocytes in antigen- and mitogen-stimulated responses: mechanism of inhibition and relationship to interleukin 1 secretion.
A differential role for DR antigens on monocytes in antigen-stimulated as opposed to mitogen-stimulated human lymphocyte responses has been observed. A monoclonal anti-DR antibody used to treat monocytes caused inhibition of antigen-induced T-cell responses and of T-cell-dependent B-cell responses. However, anti-DR antibody treatment of monocytes did not inhibit mitogen-induced responses. Anti-DR treatment of monocytes did not induce suppression, as antigen-induced responses could be reconstituted with untreated monocytes. Anti-DR treatment of monocytes did not merely block interleukin 1 (IL-1) secretion since addition of IL-1 could not restore antigen-induced responses. Monoclonal anti-DR antibody did not directly inhibit monocyte secretion of IL-1. DR-negative monocytes, selected by antibody and complement, could not present antigen, even though they were capable of secreting IL-1. Thus, this monoclonal anti-DR antibody sterically blocks antigen presentation by monocytes without induction of suppression or inhibition of IL-1 secretion. Monocyte DR antigens appear essential for stimulation of antigen-induced responses, but DR antigens on monocytes may not be essential for mitogen-stimulated responses and do not appear to be related to the ability of monocytes to secrete IL-1.
D000911:Antibodies, Monoclonal / Q000276:immunology / Q000502:physiology*; D000941:Antigens / Q000276:immunology; D001667:Binding, Competitive; D002454:Cell Differentiation; D006684:HLA-DR Antigens; D006433:Hemocyanins; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006801:Humans; D007375:Interleukin-1 / Q000096:biosynthesis / Q000502:physiology; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000166:cytology / Q000276:immunology*; D008934:Mitogens / Q000494:pharmacology; D009000:Monocytes / Q000166:cytology / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000941:Antigens; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D007375:Interleukin-1; D008934:Mitogens; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin