T cell-mediated immunity to oncornavirus-induced tumors. II. Ability of different T cell sets to prevent tumor growth in vivo.

These studies demonstrate that two different types of protective immunologic reactions are generated in mice after inoculation with M.MSV. Type I protection, mediated by Ly1 cells, prevents MSV-induced sarcomas but has no effect on the growth of MLV+ lymphomas. This anti-MSV protection reflects induction of antivirion antibody and delayed type hypersensitivity reaction. Type II protection is mediated by Ly23 cells and prevents the growth of an MLV+ lymphoma, but has little or no protective effects against MSV-induced sarcomas. This "type II" reaction is directly related to CTL activity. The implications of these two protective reaction are discussed.