Macrophage heterogeneity in man. A subpopulation of HLA-DR-bearing macrophages required for antigen-induced T cell activation also contains stimulators for autologous-reactive T cells.
Utilizing somatic cell hybridization, we have developed a monoclonal antibody that interacts only with cells of the monocyte/macrophage (M phi) line and not with other myeloid or lymphoid cells. This antibody detects a 120,000-dalton determinant present on 37 +/- 2.8% of the peripheral blood M phi from several (HLA-DR)-disparate individuals and only depicts a subpopulation (approximately 30%) of HLA-DR-bearing M phi from any single subject. Cytolytic removal of this subpopulation of HLA-DR-bearing cells markedly diminished antigen-induced T cell reactivity, a deficiency that can be reconstituted with autologous M phi but not with either their soluble products containing lymphocyte-activating factor or with intact HLA-DR-disparate M phi. Whereas M phi bearing both the 120,000-dalton determinant and HLA-DR serve as effective stimulators for autologous mixed lymphocyte reactions. M phi bearing only HLA-DR determinants do not. However, this latter population of M phi can stimulate proliferation among alloreactive T cells. These studies indicate that the Mac-120 monoclonal antibody detects a subpopulation of HLA-DR-bearing M phi that is required for the genetically restricted presentation of conventional antigen to reactive T cells. Within the M phi population, these Mac-120+ cells constitute the most effective stimulators for autologous mixed lymphocyte reactions.
D000954:Antigens, Surface; D001327:Autoimmune Diseases / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D000949:Histocompatibility Antigens Class II; D006801:Humans; D007961:Leukocyte Migration-Inhibitory Factors / Q000276:immunology; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology*; D008970:Molecular Weight; D011948:Receptors, Antigen, T-Cell; D013601:T-Lymphocytes / Q000276:immunology*
D000954:Antigens, Surface; D000949:Histocompatibility Antigens Class II; D007961:Leukocyte Migration-Inhibitory Factors; D011948:Receptors, Antigen, T-Cell