Immunotherapy and vaccination against cancer with non-living BCG and cord factor (trehalose-6,6'-dimycolate).

A vaccine containing non-living BCG and living tumour cells prevented the growth of 106 tumour cells introduced distally into the skin of guinea-pigs at the time of vaccination. A similar effect was achieved when living tumour cells of the vaccine were replaced by tumour cells pretreated with mitomycin C. The efficacy of the vaccine was significantly increased when cord factor was added to the vaccination mixture. The percentage of cures was about 88% (17 cases) in experiments in which the vaccine contained living tumour cells, 100% (10 cases) when mitomycin C-treated cells were used. The significance and implications of the above findings are discussed.