Specific enhancement of transplantation immunity with heat-killed Mycobacterium butyricum and immunizing extracts from adenovirus 12-induced tumour cells.

Transplant immunity to adenovirus 12-induced tumour cells was demonstrated in CBA mice which had been previously immunized with extracts of homologous tumour cells. Immunization of mice with tumour cell extract together with heat-killed Mycobacterium butyricum gave better transplant immunity to tumour cell challenge than tumour extracts alone. Mice immunized with Mycobacterium butyricum alone prior to challenge with tumour cells, did not show any significant difference in the incidence of tumours from control mice.