The antitumor effect of interferon against murine osteogenic sarcoma.

The antitumor activity of interferon against Dunn osteogenic sarcoma in C3H/HeN mice was studied. The administration of murine interferon prolonged the mean survival days, and reduced pulmonary metastases after the excision of the primary tumor. The administration of interferon augmented natural killer cell activity in vitro, and eliminated tumor cells from the lung rapidly. This rapid cytolysis of tumor cells occurring in vivo correlated well with NK activity in the spleens measured in vitro. These findings suggest that NK cells augmented by interferon have a major effect during the early period of pulmonary metastases.