Role of CD8 (Lyt-2) in cytotoxic T-cell function. Analysis of variants of a cytotoxic T-cell clone with reduced Lyt-2...

The role of CD8 (Lyt-2) in the function of a long-term cytotoxic T-cell (CTL) clone (Cl96) was analysed. Previous studies had shown that C196 cells utilize the alpha beta T-cell receptor and depend on Lyt-2 to recognize and lyse P815 mastocytoma target cells. Recognition is H-2Kd-restricted, presumably involving a P815 specific antigenic structure. Here we analyse a number of variants selected from Cl96 that have reduced or virtually abolished expression of Lyt-2, alone or in combination with other deficiencies. We studied the ability of these variant cells to lyse either P815, a process requiring both specific antigen recognition and triggering of cytolytic function, or to lyse the anti-CD3 hybridoma 145-2C11, a process that requires the triggering of cytolytic function only. The results shows that in the case or a permanently activated CTL effector cell such as Cl96, Lyt-2 is required for antigen recognition but is not essential for the triggering of cytotoxicity.