Monoclonal antibodies potentially useful for diagnosis of squamous cell oral carcinoma

Five murine monoclonal antibodies (MoAbs) (F1/A, F1/B, F1/C, F1/D, and F1/E) were produced that react with different antigenic determinants on the cell surface of human oral squamous cell carcinomas. They each immunoprecipitate a complex containing three polypeptides with molecular weights 38, 80, and 180 kD on SDS polyacrylamide gel electrophoresis under reducing conditions. These monoclonal antibodies were used in immunohistochemical analysis to study frozen tissue sections of surgical specimens from the floor of the mouth. Antibodies F1/A and F1/B: 1) detected virtually all malignant cells in 13/14 cases of high-grade squamous cell oral carcinomas; 2) reacted weakly with nonneoplastic cells in oral biopsies showing severe dysplasia; and 3) did not react with normal stratified squamous epithelium. In comparison, antibodies F1/C, F1/D, and F1/E reacted only with approximately 50% of oral carcinomas, but not with cells in dysplastic oral lesions. These MoAbs were able to sensitize squamous tumor cells to killing by antibody-dependent cellular cytotoxicity (ADCC) cells and complement-mediated cytolysis. Our data suggest that these antibodies may be potentially useful for diagnosis and perhaps treatment of squamous cell oral carcinoma.