Functional subsets of human monocytes defined by monoclonal antibodies: a distinct subset of monocytes contains the cells capable of inducing the autologous mixed lymphocyte culture.
The induction of most immune responses requires the close cooperation between T cells and antigen-presenting cells (APC), presumably of monocyte/macrophage (M phi) lineage. To characterize human APC further, we used two monoclonal antibodies, OKM1 and OKM5, to isolate and identify M phi subsets. OKM1 has been described and recognizes cell surface antigens on most M phi and granulocytes. OKM5 recognizes cell surface determinants present on the majority of human M phi but does not recognize other hematopoietic cell types. A small subset of peripheral blood M phi is OKM1-OKM5+. Human peripheral blood E- cells were separated into OKM1+ and OKM1- subsets by a rosetting technique utilizing anti-Ig-coated red cells. The capacity to present self antigens in the autologous mixed lymphocyte culture (AMLC) resided predominantly within the E-OKM1- subset, even if surface membrane Ig-positive cells were eliminated. Similar experiments showed that the ability to stimulate in AMLC was contained in the E-OKM5+ population and in fact resided primarily within the E-OKM1-OKM5+ subset. All of these subsets were able to trigger allogeneic T cells to proliferate. The capacity of these APC subsets to present soluble antigens (mumps, tetanus toxoid) was also examined. The data demonstrated that although the majority of these APC are E-OKM1+, E-OKM1-OKM5+ cells can also present foreign antigen. Taken together, these data suggest OKM1 and OKM5 can be used to isolate two functionally distinct human M phi subsets. One subset (E-OKM1+) is capable of presenting soluble antigens but shows minimal ability to trigger AMLC. The other subset (E-OKM1-OKM5+) can also present soluble antigens but is the predominant subset that can trigger AMLC.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology; D002469:Cell Separation; D004306:Dose-Response Relationship, Immunologic; D006801:Humans; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D009000:Monocytes / Q000145:classification* / Q000276:immunology / Q000648:ultrastructure; D012397:Rosette Formation; D013601:T-Lymphocytes / Q000276:immunology; D013745:Tetanus Toxoid / Q000276:immunology
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D013745:Tetanus Toxoid