Effect of human and mouse interferon and of polyriboinosinic acid·polyribocytidylic acid on the growth of human fibrosarcoma and melanoma tumors in nude mice☆

Abstract Human leukocyte interferon, human fibroblast interferon, mouse interferon and an interferon inducer, polyriboinosinic acid·polyribocytidylic acid (poly(I)·poly(C)), were examined for their effect on the growth of two human tumor cell lines in athymic nude mice. The human tumor cell lines were derived from a fibrosarcoma (designated HT- 1080 ) and a nonmelanotic melanoma (designated A- 375 ). Repeated doses of 5 mg/kg of poly(I)·poly(C), administered every other day starting 1 day after tumor cell inoculation, caused a significant inhibition of tumor growth. On the contrary, human (leukocyte or fibroblast) interferon and mouse interferon, at doses up to 5 × 10 6 units/kg , did not affect the growth of either of the two human tumor cell lines tested.