EFFECT OF IMMUNISATION WITH HEAT-KILLED MICRO- ORGANISMS ON TRANSPLANTATION IMMUNITY TO ADENOVIRUS-12-INDUCED TUMOUR CELLS

SUMMARY Cell-free extracts of adenovirus-12-induced tumours were used to immunise CBA mice against transplantation of the homologous tumour cells. Greater immunity was obtained when heat-killed Mycobacterium butyricum was added to the tumour extract. Less conclusive results were obtained with Coryne-bacterium parvum. In contrast, tumour cell extract plus Bordetella pertussis, Escherichia coli or Staphylococcus aureus gave significantly less immunity than did the tumour extract alone. Listeria monocytogenes and Candida albicans had no effect on immunity to tumour challenge. The enhancement or depression of immunity appeared to operate through cellular rather than humoral or antibody mechanisms.