Renal Cell Carcinoma Neoplastic Antigens

Abstract

A renal cell carcinoma neoplastic antigen was purified from a freeze-thaw extract of cultured tumor cells using immunoaffinity chromatography. In addition, renal cell carcinoma immune complexes were also isolated from the serum of a patient with metastatic disease. This was done using a previously described renal carcinoma selective monoclonal antibody covalently linked to Sepharose 4B. The crude samples were passed through the column and the antigens and immune complexes were eluted with an acidic buffer. The neoplastic antigen was represented as a single protein band with a molecular weight of 61kd on SDS polyacrylamide slab gel electrophoresis under reducing conditions. The blood serum eluate showed four distinct bands with molecular weights of 70, 50, 23 and 61 kd. Using immunoblotting assays, the first three bands were found to be IgG heavy, IgM heavy and IgG light antibody chains, respectively. The 61kd band was the neoplastic antigen. These results suggest that the antibody may be useful in a clinical assay for the detection and monitoring of renal cell carcinoma.