CELLULAR INTERACTIONS CONTROLLING THE IMMUNE REACTIVITY OF T-LYMPHOCYTES

The sequence of developmental processes of thymus-derived lymphocytes can be classified into two distinct stages. The first stage constitutes the appearance of lymphocytes in the thymus capable of recognizing antigenic signals. Such lymphocytes leave the thymus and colonize the spleen and lymph nodes. The second stage involves the response of thymocytes to antigenic signals. When a given cell-bound antigen triggers thymocytes capable of recognizing the antigen killer cells develop capable of lysing target cells possessing the same surface antigens that triggered their development. Studies indicated that both these stages are regulated by cell interactions. Results of the following studies are reported: in vitro induction of T-cell properties by thymus reticulum cells; interactions between thymocytes and the differentiation of effector cells; and control of the differentiation of effector lymphocytes by suppressor T-cells. (HLW)