| Abstract: | Intramuscular inoculation of murine sarcoma virus of Moloney (MSV-M) leads to the development of tumors at the site of injection. The effect of BCG treatment on tumor induction by MSV-M in BALB/c mice was studied. Mice injected with BCG 28 days before induction of tumors with MSV-M alone had shorter latent periods for tumor development and longer survivals than mice not previously exposed to BCG. When BCG was mixed with the MSV-M used for tumor induction there was a significant decrease in mortality, tumor incidence, and tumor size compared to those seen in mice inoculated with MSV-M alone. Previous exposure of the mice to BCG before attempted induction of tumors with the mixture of BCG and MSV-M completely inhibited tumor development. In addition, these mice were effectively immunized against tumor development when subsequently challenged with a lethal dose of MSV-M. The mechanisms of BCG's impressive activity are discussed. |
