The growth and spontaneous dissemination of melanoma B16 and Lewis lung tumour in two sub-strains of C57BL/6J mice treated with Corynebacterium parvum and/or levamisole.

The effect of C. parvum and/or levamisole on tumour growth and spontaneous dissemination was tested in two tumour-host systems, melanoma B16 and LLT in C57BL/6J mice. C. parvum inhibited the growth of LLT and its dissemination to the lungs and the growth of B16 in females in one of the two sub-strains of mice used. Levamisole stimulated the growth of B16 in females in one sub-strain and in both sexes in the other sub-strain of mice. The growth of LLT was not influenced by levamisole but its dissemination to lymph nodes was facilitated. The growth-stimulating effect of levamisole was abrogated by C. parvum in the mice treated with both agents in combination. It is concluded that the effects of non-specific immunomodulators on tumour growth and spread can vary between sub-strains of the same inbred strain of mice bred at different laboratories.