Separation of Helper a N D Suppressor T Lymphocytes

The existence of subpopulations of T cells has been recognized in a number of experimental models. Raft and Cantor (1) first subdivided T cells into T1 and T2 according to an antigen-driven maturation scheme. T1 cells which were immature, short-lived, and noncirculating upon encounter with antigens developed into mature T~ cells which were long-lived, circulating, and had a lower density of Thy-1 antigen on the cell surface. More recently it would appear that the T1 and T2 progression may occur in a number of parallel T-cell subpopulations and it may be more appropriate to subdivide T cells on a functional basis into TN, the helper cells carrying Ly-1 antigens and Tc.s, the cytotoxic and suppressor T cells carrying the Ly-2,3 antigens (references 2-4 and H. Cantor, personal communication). Although cytotoxic and suppressor T cells have been separately detected in many different systems (5-8), their relationship to each other remains unclear and they are tentatively grouped together. It should also be noted that cell cooperation is not limited to Tand B-cell systems. Collaboration between T-cell subpopulations in the generation of effector T cells has been suggested in a number of experimental systems (e.g. Asofsky et al. (9); Bach and Bach (10)). While the helper and cytotoxic functions of T cells are now more or less established concepts (5, 11), the functional role of T-suppressor cells is less well defined. Gershon (6) was among the first to observe that cells from mice made tolerant to sheep erythrocytes (SRBC) when transferred to normal mice conferred tolerance on the recipient. This "infectious" phenomenon could be completely abrogated by anti-0 treatment. In other systems, Herzenberg and Herzenberg (12), Baker et al. (13), Tada and Takemori (14), Rich and Pierce (7), and Dutton (15) provide further evidence for the existence of suppressor cells. On the other hand, Coutinho and M611er (16) have proposed a "one nonspecific signal hypothesis" and suggested that suppression is merely due to too much help. The answer as to whether helper and suppressor T cells are distinct subpopulations will help resolve this dilemma. We have previously shown that the incubation of mouse spleen cells with concanavalin A (Con A) ~ induced both helper and suppressor activities for the