ROLE OF INTERLEUKIN-2 RECEPTORS IN THE SUPPRESSIVE EFFECT OF SPLEEN-CELLS FROM ANTI-CD3-TREATED MICE

In the present study, we demonstrate that unresponsive spleen T cells from mice injected with a low dose of anti-CD3 mAb (single 10 mu g i.v . injection) significantly inhibit Con A-induced proliferation of norm al spleen cells. The induction of this phenomenon requires in vivo act ivation since spleen cells from mice injected with the F(ab')(2) fragm ent of anti-CDS mAb fail to promote it, Suppression of normal T cell p roliferation is concomitant with increased expression of IL-2 receptor on spleen cells from anti-CD3-treated mice. It disappears within 3 da ys when IL-2R has returned to background levels. A normal proliferativ e response to Con A can be restored when high concentrations of IL-2 a re added together with the ''suppressor'' cells. Taken together, these data support the notion that activated spleen cells from anti-CD3-inj ected mice exert their inhibitory effect by competing for the IL-2 gen erated during culture.