DNA immunization induces protective immunity against B-cell lymphoma.

Idiotypic determinants of the immunoglobulin expressed on the surface of B-cell lymphomas are tumor-specific antigens (TSAs), which can be targeted by immunotherapy. Immunization with DNA constructs encoding the idiotype (ld) of a murine B-cell lymphoma induced specific anti-ld antibody responses and protected mice against tumor challenge. Use of DNA encoding an ld/GM-CSF (idiotype/granulocyte-macrophage colony-stimulating factor) fusion protein improved vaccine efficacy, and xenogeneic immunoglobulin constant region determinants were required for immunogenicity. These results indicate that DNA may be a simple and efficacious means of inducing immune responses against a weak, otherwise unrecognized tumor antigen, provided that additional stimuli are included with the DNA.