Retention of antimelanoma effect of polyinosinic-polycytidylic acid in neonatally thymectomized, irradiated, leukopenic mice.
Polyinosinic-polycytidylic acid (PIC), a synthetic polyribonucleotide, inhibits the growth of B16 malignant melanoma in C57BL/6 mice. Since PIC has been reported to augment immune responses, we tested the hypothesis that the antitumor effect of PIC against B16 melanoma is via immune stimulation. Mice were neonatally thymectomized or neonatally thymectomized and subsequently irradiated to suppress their immune reactivity. In such animals PIC retained its ability to inhibit the growth of B16 melanoma, in the face of profound leukopenia and lymphopenia, suggesting that its antimelanoma effect is probably not mediated by augmentation of the host's immune antitumor response.
D000818:Animals; D000831:Animals, Newborn; D007372:Interferons / Q000096:biosynthesis / Q000097:blood; D007970:Leukopenia / Q000150:complications; D008545:Melanoma / Q000150:complications / Q000188:drug therapy* / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000188:drug therapy / Q000276:immunology; D011070:Poly I-C / Q000627:therapeutic use*; D013934:Thymectomy; D014184:Transplantation, Homologous
D007372:Interferons; D011070:Poly I-C