Specificity analysis of mouse monoclonal antibodies defining cell surface antigens of human renal cancer
Six mouse monoclonal antibodies (mAbs) defining separate systems of cell surface antigens of cultured human renal cancer were tested for reactivity with normal fetal and adult tissues and with neoplastic tissues. Five of the mAbs identified glycoproteins of Mr 160,000 (designated S4), Mr Mr 140,000 (F23), Mr 120,000 (S23 and S27), and Mr 115,000 (S22). The glycoprotein component of Mr 120,000 has been shown recently to be the adenosine deaminase binding protein (ADA-BP) and mAbS23 and mAbS27 define two distinct epitopes on ADA-BP. S22 was not detected on any normal fetal or adult tissues but was found on a subset of renal cancers. S4, F23, S23, and S27 defined distinct domains of the nephron: glomerulus (S4), proximal tubules (S4, F23, S23, and S27), and portions of Henle's loop (S23 and S27). mAbS4 also reacted with the interstitial matrix in the renal medulla and of other tissues, and mAbF23 reacted with fetal and adult fibroblasts. The S23 epitope of ADA-BP was expressed by placental trophoblasts and epithelial cells of breast, prostate, lung, and colon, whereas the S27 epitope was detected on a more limited range of cell types (trophoblasts and prostate epithelium). A panel of 20 renal cell carcinomas was typed for expression of these antigens; 7 phenotypes could be distinguished, with the S4+/F23+/S23+/S27+/S22+ or - phenotype (15 cases) being most common. The other antigenic system, V1, identified a heat-stable antigen that was widely expressed on cultured cell types but showed a restricted pattern of reactivity in tissues. V1 expression was limited to the adrenal cortex, Leydig cells, and the theca of ovarian follicles, and to adrenal cortical carcinomas.