A renal cell carcinoma neoplastic antigen detectable by immunohistochemistry is defined by a murine monoclonal antibody

BALB/c mice were hyperimmunized with ACHN (ATCC CRL 1611, American Type Culture Collection, Rockville, Maryland), a stable in vitro cell line derived from a malignant pleural effusion in a 22-year-old man with renal cell carcinoma. The hyperimmune spleen cells were fused with NS-1 murine myeloma cells using polyethylene glycol. Hybridoma supernatants were screened for the presence of IgG reactive with detergent extracts of ACHN and nonreactive with detergent extracts of normal kidney tissue. A stable, rapidly growing clone named 5F4 was isolated. Supernatant from 5F4 was used as a primary antibody preparation for avidin-biotin complex immunoperoxidase staining of multiple cases of renal cell carcinoma, normal tissues, and other tumors. 5F4 produced IgG which reacted with a cytoplasmic structure in paraffin-embedded sections of all renal cell carcinomas tested. There was occasional, weak, granular, cytoplasmic staining of isolated tubular lining cells in adjacent normal kidney.