604 INHIBITORY ACTIVITY OF TYPE I & TYPE II INTERFERON AGAINST TRANSPLANTABLE OSTEOGENIC SARCOMA IN MICE

Abstract

Interferon (IF) has been recognized to have antitumor as well as antiviral activity. Strander et al. have reported possible therapeutic effects of human IF in patients with osteosarcomas. To study the antitumor activity of IF under more controlled conditions we have utilized a 239Pu-induced osteogenic sarcoma (OGS) in mice as a model system. We previously reported that growth of murine OGS cells in tissue culture was inhibited by IF. In the present study the effect of IF on the growth of transplantable OGS in mice was determined. Two tynes of IF were utilized-type I (viral-induced) IF and type II (immune) IF. Mice inoculated sc with 1×105 OGS cells were treated daily with 32,000 U type I IF at the tumor site for 7 days. The time of appearance of tumors was increased by approximately 40 days. Utilizing a similar treatment schedule the antitumor effects of type I and type II IF were compared using groups of 10 animals: These data extend in vitro studies which demonstrated that OGS cells were inhibited by IF and indicate that: (1) transplantable murine osteosarcomas can be inhibited by local treatment with IF and (2) type II IF was more effective than type I IF in this experimental model.