Tumor-Graft Rejection in Syngeneic Guinea Pigs: Evidence for a Two-Step Mechanism

Abstract

The growth of a transplantable strain-2 hepatoma was suppressed at the site of delayed hypersensitivity skin reactions to another, antigenically different, transplantable strain-2 hepatoma and at the site of delayed hypersensitivity skin reactions to bacterial antigens. The ability to kill antigenically unrelated tumor cells by delayed hypersensitivity skin reactions could be transferred from sensitized donors to unimmunized recipients by means of peritoneal exudate cells. Close contact between sensitized cells, sensitizing antigen, and the antigenically unrelated tumor cells was required to suppress growth of the antigenically unrelated tumor cells. Tumor-graft rejection occurring without delayed hypersensitivity skin reactions did not cause suppression of antigenically unrelated tumor cells.