[Antitumor effect of human recombinant interferon-alpha A/D in mice(I): Comparison between systemic and lesional treatment of meth-A sarcoma in BALB/c mice].

Human recombinant interferon-alpha A/D (IFN-alpha A/D) is known to be as active on murine cells as on human cells. We studied the antitumor effect of pure IFN-alpha A/D on Meth-A sarcoma cells in vivo. When administered systemically (intraperitoneally), IFN-alpha A/D (total dosage: 7 X 10(5) units/mouse) was only marginally but significantly (p less than 0.05) effective in reducing the growth of Meth-A sarcoma cells transplanted subcutaneously into syngeneic BALB/c mice. By lesional (intra-tumor) administration (total dosage: 5 X 10(4) to 5 X 10(5) units/mouse), however, IFN-alpha A/D strongly inhibited the growth of Meth-A sarcoma cells and even led to a complete regression of tumor growth and subsequent immunity to Meth-A sarcoma cells in the host animals when treatment was started early after transplantation and at a high dose. Indomethacin or cyclophosphamide administered intraperitoneally at a dose at which, although not directly effective against tumor growth, both were expected to stimulate the host immune system by inhibiting suppressor macrophage function or suppressor T cells, respectively, showed neither enhancing nor suppressing effect on the above mentioned strong antitumor effect of locally administered IFN-alpha A/D.