Cytotoxic lymphocytes in the lungs of mice infected with respiratory syncytial virus.

Mice infected with respiratory syncytial virus (RSV) developed cytotoxic lymphocytes in the lungs, which lysed RSV-infected, but not uninfected cells. Cytotoxic activity was greatest 7 to 9 days after infection, was virus-specific, MHC-restricted and abolished by treatment of lymphocytes with anti-Thy 1.2 or with anti-Lyt 2.2 sera and complement. There was a close temporal relationship between the appearance of these cytotoxic lymphocytes in the lung and clearance of virus. In contrast, RSV persisted in the lungs of athymic (nude) mice and such animals failed to develop RSV-specific cytotoxic lymphocytes. Thus, cytotoxic T-cells may have an important role in recovery from RSV infection.