[Antitumor activity of BCG--inhibition and enhancement of tumor growth by anti-BCG rabbit serum].
Administration of heat-killed BCG into BALB/c mice with colon 26 tumors which have common antigens to those of BCG has been shown to enhance tumor growth. The present experiments were undertaken to clarify this phenomenon. It was found that anti-BCG rabbit serum played a role in augmenting tumor growth when injected intraperitoneally into tumor-bearing mice. Interestingly, bi-phasic activity of anti-BCG rabbit serum (inhibition and enhancement of tumor growth) was observed, which was dependent on the concentration of BCG antibodies present. By contrast, immune-complex prepared with BCG antigen-antibody was not considered to be an agent for directly enhancing tumor growth. It was therefore concluded that anti-BCG rabbit serum was a specific agent for augmenting tumor growth.