Influence of micrococcus, BCG and related polysaccharides on the proliferation of the L1210 leukaemia.

A comparative study of the effects of BCG, Micrococcus lysodeikticus, and a series of structurally related polysaccharides (complement triggers) on the non-specific and specific immune resistance against L1210 lymphoid leukaemia was carried out and commented on. In contrast with authors of earlier reports, we were unable to generate any effective non-specific or specific immunotherapy after the graft of 10(4) leukaemic cells to 8--10-week-old CDF1 mice. However, when mice were prevaccinated with irradiated (8 krad X-rays) cultured cells combined with 1 mg of bacterium or polysaccharide one month before grafting 10(4) cells, they were given an immunoprotection that was more pronounced with the i.p. than with the i.v. route. Prevaccinated mice were afforded a stronger immunoprotection when boosted repeatedly with 1mg injections of bacterium or polysaccharide after tumour challenge.