Highly Immunogenic Transformed Tumor Clones Expressing Allogeneic Class I Histocompatibility Gene Demonstrate a Specific Immunotherapeutic Affect Against the Parental Tumor

In this study, the possibility of generating tumor-specific immunity by the introduction of allogeneic class I histocompatibility gene into tumor cells was investigated. Specifically, we have expressed the H-2Kb gene in the non-immunogenic AKR leukemia K36.16. Thirty-eight H-2Kb-transformed K36.16 clones (Kb/K36.16) were isolated and studied individually. Different amounts of the H-2Kb antigens were detected on the surface of these Kb/K36.16 transformed clones. As expected, the expression of the H-2Kb antigens on the K36.16 tumor cells led to the rejection of the transformed clones by semi-syngeneic AKR mice. It was also noted that AKR mice which had been immunized with the Kb/K36.16 clones were able to survive a subsequent challenge of the parental K36.16 tumor cells. More importantly, from the clinical point of view, some of these Kb/K36.16 clones could induce a specific immune response against the growth of the K36.16 cells in tumor-bearing AKR mice. Such immunotherapeutic observation reinforces the feasibility of using gene-transfer as a molecular approach to abrogate tumor growth.