RP215 Monoclonal Antibody-Based Anti-Cancer Vaccines

RP215 is a monoclonal antibody generated against an ovarian cancer cell extract. RP215 was shown to react specifically with a carbohydrate-associated epitope located mainly in the variable regions or Fab regions of heavy chain immunoglobulins designated in general as CA215. This unique and specific epitope was shown to be expressed by almost all cancer cells in humans, but not detected in normal immunoglobulins of B cell origins. Through extensive studies during the last two decades, RP215 was shown to be a good cancer biomarker which reveals strong inhibitions to many human cancer cells in vitro or in vivo. RP215-specific epitope was found to be immunodominant, since only RP215 epitope-related monoclonal antibodies were generated upon immunization of mice with RP215-affinity purified CA215 as the immunogens. Therefore, rat anti-idiotype (anti-id or Ab2) monoclonal antibodies were generated against RP215-idiotypic regions and shown to bear the internal images of RP215-specific epitope. Following immunizations of mice with purified rat anti-id (Ab2), the induced Ab3 sera revealed similar immunological and biological properties to those of original RP215. Therefore, anti-id (Ab2) in this case may serve as immunogens or vaccines to elicit strong Ab3 which mimic passively immunized RP215 in many anti-cancer properties. It can be suggested that anti-id monoclonal antibodies can be suitable candidates for development of anti-cancer vaccines which may have potential clinical applications in therapeutic or preventive treatments of human cancer.