[Specific interaction of phagocytosing mononuclears with T cells during formation of the thymocyte-induction factor]

Data are provided on specific secretion by macrophages of a factor inducing the functional differentiation of thymocytes. The contact of mononuclear phagocytes with lymphocytes of T-cell type induces the formation of this transmitter. Interaction of macrophages with B-cells does not lead to the secretion of this monokine. Treatment of macrophages with nonspecific stimulators exerts no effect on the production of the factor.