ANTITUMOR EFFECT OF JUZENTAIHO-TO, A KAMPO MEDICINE, COMBINED WITH SURGICAL EXCISION FOR TRANSPLANTED METH-A FIBROSARCOMA

The present study demonstrates the antitumour effect of treatment comb ining Juzentaiho-to (TJ-48, a kampo medicine) with surgical excision ( SE) in mice using Meth-A fibrosarcoma. TJ-48 showed no direct cytotoxi city against Meth-A tumour cells in vitro, and oral administration of TJ-48 alone exhibited no inhibitory effect on the growth of intraderma lly inoculated Meth-A tumour cells. TJ-48, however, displayed a marked antitumour effect when combined with SE. When oral administration of TJ-48 (0.5 g/kg/day) was begun on post-excision day 1, the growth of t he secondary tumour inoculated on post-excision day 7 was greatly inhi bited. Where this inhibitory effect was obtained, TJ-48 was found to e nhance cell-mediated immunity (anti-Meth-A delayed-type hypersensitivi ty response). In tumour-neutralization tests, spleen cells from mice t reated with both TJ-48 and SE markedly inhibited the growth of admixed Meth-A tumour cells. The antitumour immunity of the spleen cells was abolished by treatment with anti-L3T4 monoclonal antibody plus complem ent but not with anti-Lyt-2 monoclonal antibody plus complement. Accor ding to the analysis of lymphocyte subpopulations, the number of L3T4- positive cells was increased by TJ-48 administration. These results su ggest that TJ-48 augments antitumour immunity in combination with SE a nd the effect is mediated by L3T4-positive T cells.