[Effects of levamisole on methylcholanthrene-induced tumor. I. Its antitumor effect and immunological mechanism]

Malignancy and antigenicity of fibrosarcoma Meth 1 cells induced in a BALB/c mouse were compared with sarcoma Meth A cells. Furthermore, antitumor effect of levamisole (LMS) against Meth 1 cells and its immunological mechanism were studied. 1) The lifespan of BALB/c mice inoculated i.p. with 10(2) Meth 1 cells was prolonged by the treatment with LMS. 2) Growth of s.c. inoculated secondary tumors was tumor-specifically inhibited in solid Meth 1-bearing mice as compared with that in non-tumor-bearing mice. Administration of LMS (0.625 or 2.5 mg/kg) augmented the growth inhibition of these secondary tumors. 3) Spleen cells of Meth 1-bearing mice showed a growth-inhibitory activity against Meth 1 cells in Winn assay. LMS (0.625 or 2.5 mg/kg) augmented such a growth-inhibitory activity of spleen cells. The activity was attributed to non-adherent, thy 1-positive spleen cells.