Cell-mediated immune reactions to tumor antigens with particular emphasis on immunity to human neoplasms

Findings on lymphocyte-mediated destruction of animal and human tumor cells plated in vitro are reviewed. The role of blocking, “unblocking,” “potentiating,” and “arming” serum factors in tumor immunity is discussed. Evidence is presented from studies on human tumors that the in vitro measurement of lymphocyte-mediated tumor cell killing and blocking serum activity (abrogating tumor cell killing by lymphocytes) shows a clinical correlation.