Effect of Antibody to 9 Antigen on Cell-Mediated Immunity Induced in Syngeneic Mice by Murine Sarcoma Virus 2

Mice were immunized with murine sarcoma virus and their lymphocytes tested for cytotoxic reactivity in a 51chromlum release assay. The positive reactions obtained at 1470 days after immunization were strongly inhibited by pretreatment of the lymphocytes with anti-θ antibody and complement. An antiglobulin reagent, previously shown to inhibit lymphocyte-dependent antibody cytotoxicity, had no effect. These experiments indicated that θ-positive lymphocytes were responsible for most of the immune reactivity. In contrast, normal lymphocytes also had low levels of cytotoxic reactivity, and this was not eliminated by anti-θ.