Tumor immunity induced by preimmunization with BALB/c mouse myeloma protein

Prior sc immunization of BALB/c mice with 1 mg isolated M component of MOPC-11 mouse myeloma resulted in significant relative immunity to subsequent sc or ip challenge with 10(4) living cells from the same plasmacytoma. However, challenges of 10(5) and 10(6) tumor cells overcame immune status engendered by preimmunization with M component. Despite evidence for the specificity of the immunity induced by one isolated M component as opposed to another, no clear cytotoxic antibody, cell-mediated tumor-cell lysis, or predominance of either humoral or cell-mediated immune mechanisms were demonstrated. These findings were compatible with a relatively slight tumor-specific antigenicity of M components expressed on tumor surfaces, compared with the tumor specificity of other tumor-related, cell-surface antigens.