Development of suppressor T cells by antilymphocyte serum treatment in mice.

Administration of rabbit anti-mouse lymphocyte serum (ALS) in mice results in the development of suppressor cells which can be detected by coculture mixed lymphocyte culture experiments. The putative suppressor cells inhibit nonspecifically the proliferative response as well as generation of cytotoxicity of normal responder cells. Suppressor activity is dose dependent and is not attributable to cell crowding, shifting of peak activity, or release of cell-bound ALS. Additional antigenic stimulation by skin allografting in ALS-treated mice shifts the specificity of suppressor cells from nonspecific to specific for skin donor alloantigen. ALS-induced suppressor cells are Lyt-1+2- T cells while suppressor cells present in ALS-treated, skin allograft-bearing mice are Lyt-1-2+ T cells. Both types of suppressor cells appear to bear I-J determinants. The possible mechanisms of suppressor cell induction by ALS and skin allografting are discussed.