In an attempt to investigate the role of the immune system in oral squamous cell carcinoma, an animal model was developed with an inbred strain of mice. Well-differentiated oral squamous cell carcinomas were induced with a polycyclic hydrocarbon in immunogenetically identical mice. The oral tumors that developed were maintained in vivo. Once established, the tumors were adapted to tissue culture and the resulting cell lines were cloned. An immunization protocol was formulated to detect the generation of cytolytic effector cells by using a microcytotoxic chromium-51 release assay to assess the immune response of the host.