Selective functional role of murine Tm and Tg cells in concanavalin-A-induced T-cell activation.

Abstract

Murine splenic cells were separated on Ig-anti-Ig columns to yield cell populations depleted of IgM-FcR (Fc receptor)-expressing (TM) and IgG-FcR-expressing (TG) cells and also cells expressing neither of these two FcR (TO). The proliferative response to the lectin concanavalin A (Con A) was shown to be present mainly in cell populations depleted of TM cells (T cells lacking IgM FcR)--that is, TM and TO. The low Con A response in the other cell populations, namely TG and TTOT, was due to a selection against T-cell growth factor (TCGF)-reactive cells, since TCGF production within these subsets was not impaired and the low proliferative response was not reconstituted by preformed TCGF. TG-cells were able to inhibit the Con-A-induced proliferation of TO and TM cells dose-dependently. These data strongly suggest the presence of a step-one regulatory, suppressive mechanism comprised within the TM population.