Dissociation of autologous and allogeneic mixed lymphocyte reactivity by using a monoclonal antibody specific for human T helper cells.
A monoclonal antibody defining a population of human T helper cells was developed and shown to specifically block the autologous mixed lymphocyte reaction (AMLR). This antibody, termed KT69-7 (IgG1), recognized 62% of peripheral blood E rosette-positive (E+) cells while demonstrating negligible reactivity with E- cells, monocytes, granulocytes, EBV-transformed B cell lines, and mouse splenocytes. Separation of E+ cells into KT69-7+ and KT69-7- populations revealed that KT69-7+ T cells provided helper function in PWM-driven B cell differentiation, whereas KT69-7- T cells provided no help and may suppress this response. Modulation of membrane moieties by using KT69-7 or OKT4 plus goat anti-mouse IgG removed reactivity to both these antibodies, suggesting an association between these molecules recognized by these antibodies. In functional studies, KT69-7 selectively blocked the AMLR while demonstrating minimal or no effect on the allogeneic MLR (allo-MLR). Blocking of the autoreactivity occurred when either autologous B lymphocytes or macrophages were used as stimulators. The failure of KT69-7 to block the allo-MLR was not attributable to excessive allogeneic stimulus; KT69-7 failed to block even under conditions of limiting numbers of stimulator cells. KT69-7 thus appears to recognize a molecule on the surface of T helper cells required for recognition of autologous class II antigens.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000502:physiology; D000918:Antibody Specificity; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology; D001667:Binding, Competitive; D002454:Cell Differentiation; D006801:Humans; D007152:Immunologic Capping; D007959:Lymphocyte Culture Test, Mixed; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D011043:Pokeweed Mitogens / Q000494:pharmacology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D000911:Antibodies, Monoclonal; D011043:Pokeweed Mitogens