T‐Lymphocyte Recognition of Alloantigen In Vitro

The present report deals with our attempts to characterize the potent stimulator cell(s) that induce Fc receptor (FcR)-negative T lymphocytes to differentiate into cytotoxic T lymphocytes in vitro. We found two categories of such cells: [1] resting B cells, FcR+ T cells, and macrophages and [2] T cells either activated in 800-R-irradiated mice against H-2 antigens or M-locus antigens or activated in vitro by concanavalin A. The distinction between potent and weak stimulator cells is discussed in relation to the surface antigenic markers and the immunological function of these cells.