[Shared antigens between BCG and tumor cells--immunotherapy with BCG for mouse tumor]

Cytotoxic activity of anti-BCG rabbit serum (A-BCG) and the antigenic relationship between BCG and tumor cells were studies. A-BCG showed high cytotoxic activity against line 10 tumor cells of guinea pig Strain 2 and Colon 26 tumor cells of BALB/c mouse but not to cells of human bladder cancer (HT 1197, HT 1376). Cell-killing activity of A-BCG against line 10 and Colon 26 was dependent on complement participation. It was also found that Colon 26 cells were heterogenous in their susceptibility to the killing activity of A-BCG. Antigenic studies between BCG and tumor cells were undertaken using on indirect immunofluorescence method and it was found that all tumor cells used in the experiment shared common antigens with BCG. In immunotherapy with BCG for Colon 26 tumors, BCG worked effectively for suppressing tumor growth. However, enhancement of tumor growth in some of the BCG-treated mice was observed.