Monoclonal antibodies against squamous cell carcinoma of the upper aerodigestive mucous membranes.

BALB/c mice were immunized with viable cells from human squamous cell carcinoma (SCC) cell lines derived from maligant tumors of the upper aerodigestive tract. Hybridomas were selectively grown for the production of monoclonal antibodies. About 700 hybridoma clones produced antibodies that were tested for immunoreactivity in frozen sections of human SCC and hyperplastic tonsils. Monoclonal antibodies produced by the hybridoma clone K-640 were strongly accumulated at the cell membrane of SCC cells, whereas no immune reaction was detected in the squamous epithelium of the tonsil. This study describes cloning and recloning of the K-640 clone, which enabled further enhancement of the antigen specificity. The antibodies of this highly selected clone belong to the IgM class, as shown by isotype determination with an ELISA. Immunoblotting exhibited that the antibodies recognized an antigen with an approximate molecular weight of 55 kD.