title: Biologic functions of the OKT1 T cell surface antigen. I. The T1 molecule is involved in helper function.
abstract: The OKT1 (Leu-1) monoclonal antibody reacts with a 69 KD glycoprotein that is present on only a fraction of functionally mature thymocytes but is maintained on most peripheral T cells. In the study presented, we examined the role of this surface molecule in T cell function. We found that addition of the OKT1 antibody to B cells and autologous T4+ cells markedly enhances B cell differentiation. This enhancement was apparent when nonirradiated or irradiated T4+ cells but not T8+ cells were used. Moreover, the OKT1 antibody as well as the OKT1 F(ab')2 fragment enhanced B cell differentiation in a dose-dependent fashion. It is important to note that perturbation of the T1 molecule with OKT1 in the presence of autologous E- cells causes the rapid release of molecules that trigger B cells to proliferate and differentiate into Ig-secreting cells. These data when considered together suggest that OKT1 reacts with a T cell membrane determinant or a complex that is intimately involved in the execution of helper function on OKT4+ cells.
mesh_terms: D000911:Antibodies, Monoclonal / Q000502:physiology; D000921:Antibody-Producing Cells / Q000166:cytology; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000276:immunology*; D001402:B-Lymphocytes / Q000166:cytology; D002454:Cell Differentiation; D006133:Growth Substances / Q000096:biosynthesis; D006801:Humans; D015847:Interleukin-4; D008211:Lymphocyte Cooperation; D008222:Lymphokines / Q000096:biosynthesis; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology* / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D006133:Growth Substances; D008222:Lymphokines; D015847:Interleukin-4