Transfection of the undifferentiated murine colon carcinoma line CT-26 with the gene coding for the hemagglutination antigen (HA) of influenza virus resulted in the generation of highly immunogenic tumor cells. CT-26 cells transfected with HA not only failed to grow in syngeneic mice but also protected normal animals against a challenge with otherwise lethal doses of parental nontransfected cells. The immunogenicity of HA-transfected cells appeared to correlate with surface HA expression in that tumorigenic clones of HA-transfected CT-26 cells expressed little HA, while immunogenic clones were high expressers of HA. Irradiation of immunogenic HA clones did not abrogate their immunogenicity. These observations demonstrate that immune recognition of a poorly immunogenic tumor can be produced by immunization with tumor cells expressing a defined, foreign cell surface antigen.
This work was supported by the Clayton Fund and Grants CA-41525 (P. F.), CA-39853 (P. F.), GM 07309 (E. R. F.), GM 07184 (E. R. F.), and CA-35494 (B. V.) from the NIH, Department of Health and Human Services. Dr. Itaya is an R. E. “Bob” Smith Educational Fund Fellow.