Functional characteristics of human T-cell subpopulations distinguished by a monoclonal antibody

Abstract

In animals and in man, diverse immunologic functions are mediated by specialized T [thymus-derived] cell subsets that are distinguishable from one another on the basis of differences in cell surface determinants. In humans, subset-specific antibodies have been difficult to generate. In this study, production of a murine monoclonal antibody specific for a subset of human T cells was achieved by fusing a sensitized B (bone marrow-derived) cell with a myeloma cell and isolating the antibody secreted by the resultant hybrid clone. This antibody binds 30-35% of peripheral T lymphocytes (Ta+ cells) but fails to bind remaining T lymphocytes (Ta- cells), B lymphocytes or monocytes. Ta+ and Ta- subpopulations were separated with a fluorescence-activated cell sorter and their in vitro responses to various stimuli were assessed. Ta+ and Ta- cells respond equally well to soluble antigens, allogeneic B cells and autologous B cells, but only Ta+ cells respond to concanavalin [Con] A. Ta+ cells cultured in the presence of Con A gradually lose the Ta marker, an effect not observed after stimulation with phytohemagglutinin, soluble antigens or alloantigens. The functional subpopulation of T cells defined by Ta apparently does not correspond to any previously described human T cell subset. Somatic cell hybridization is a feasible method for production of monoclonal antibodies specific for subpopulations of human lymphocytes.