[Antitumor effect of OK-432 (1)--antitumor effect of OK-432 induced interferon-gamma (IFN gamma)].
Recent findings that OK-432 induces IFN gamma both in vivo and in vitro prompted us to examine the host-mediated antitumor effects of OK-432 previously observed, such as activation of cytotoxic macrophages and augmentation of NK cell activity, through the action of induced IFN. By using partially purified IFN gamma produced in vitro with mouse spleen cells in the presence of OK-432, antitumor effects were examined against Meth-A cells both in vivo and in vitro. Repeated intratumoral injections of IFN gamma (300 U/mouse) resulted in 75% inhibition of tumor growth. In vitro studies also showed that 50 U/ml was enough to inhibit the growth of Meth-A cells. Augmentation of NK cell activity was found both in vivo by a single i.p. injection of 200 U/mouse, and in vitro, with as low a concentration as 5 U/ml. When macrophages obtained from mice after i.p. injection of thioglycolate medium were treated in vitro with OK-432 induced IFN gamma, 20 U/ml was shown to activate the cytotoxic effect of M phi on Meth-A cells. All of the experiments were conducted with a positive control of purified mouse IFN-alpha/beta. With antitumor and cell activating effects compared in units, OK-432 induced IFN gamma was almost 10 times or more as active as IFN alpha/beta.
D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D001688:Biological Products / Q000494:pharmacology*; D007369:Interferon Inducers / Q000494:pharmacology*; D007371:Interferon-gamma / Q000502:physiology*; D007694:Killer Cells, Natural / Q000276:immunology; D008297:Male; D051379:Mice; D010844:Picibanil / Q000494:pharmacology*; D012513:Sarcoma, Experimental / Q000276:immunology*
D000276:Adjuvants, Immunologic; D001688:Biological Products; D007369:Interferon Inducers; D010844:Picibanil; D007371:Interferon-gamma