Effect of a synthetic adjuvant for inducing anti-tumour immunity.

An acylated derivative of muramyl dipeptide (MDP), 6-O-(2-tetradecyl-hexadecanoyl)-muramyl-dipeptide (B30-MDP) is a strong adjuvant effective in inducing cell-mediated immunity. We used B30-MDP as an adjuvant for induction of anti-tumour immunity. Guinea-pigs which were injected repeatedly with a mixture of X-ray-treated leukaemic cells and B30-MDP dissolved in phosphate buffered saline resisted a challenge of leukaemia cells and showed no sign of leukocytosis. The immunity induced was tumour-specific and retained for more than 100 days. These results suggest that B30-MDP is useful as a simple but potent immunotherapeutic tool.