[Production and characteristics of monoclonal antibodies against individual prekeratins in simple types of rat epithelium].

BALB/c mice were immunized with intermediate filaments (IF) from the rat colon mucosa, and their splenocytes were fused with myeloma cells to obtain hybridomas. Specific antibody production was assessed by indirect immunofluorescence on cultured rat hepatoma 27 containing prekeratins. The clones that stained IF in hepatoma and not in fibroblasts were judged positive. Clones E3 and E6 were shown to produce monoclonal antibodies against prekeratin with molecular mass of 40 kD (PK40), while clones E2 and E7 produced antibodies against prekeratin with molecular mass of 55 kD (PK55). This was established by immunoblotting with 125I-protein A in cell lysates from the colon, bladder, and hepatoma 27. Only PK55 was revealed in liver and salivary gland lysates. The above proteins were not detected in esophagus, fibroblast and skeletal muscle cell lysates. The monoclonal antibodies make it possible to study individual prekeratin expression in embryogenesis, differentiation and neoplastic transformation of simple epithelium.