Experimental studies of tumor immunotherapy. I. Macrophage migration inhibitory activity as an immunological parameter

The macrophage migration inhibition activity [MI activity) was stable in sensitized lymphocyte-to-marcophage ratios of 1:5 to 1:20 in mice. Antigen protein concentrations under 100 mug/ml did not induce nonspecific macrophage migration inhibition. Inhibition of tumor proliferation and survival was observed after a combined injection of BCG and MH-134 cells. After a single injection of MH-134 tumor cells, MI activity was reinforced and prolonged, demonstrating the clear effects of BCG as adjuvant. In DDS mice MI activity was weakened in the regional lymph node after a subcutaneous injection of just above or below 10(5) Ehrlich cancer cells previously treated with mitomycin C. This finding suggests the presence of an optimal tumor antigen concentration.