Monoclonal antibodies raised against cell membrane components of human bladder tumor tissue recognizing subpopulations in normal urothelium.

ABSTRACT

Monoclonal antibodies to human bladder carcinoma membrane antigens were produced by fusion of MOPC-21 NS/1 mouse myeloma cells with spleen cells from BALB/c mice immunized against a crude membrane extract from a metastatic bladder carcinoma. Hybrids were screened for antibody production in a solid-phase radioimmunoassay and selected for their reactivity with subpopulations of urothelial cells on normal bladder tissue sections. Three antibody groups were defined Group I (4-72-2) was urothelium specific and stained the basal and intermediate cells in normal urothelium; group II (3-48-2, 48-1, and 3-50-3) showed reactivity with intermediate and superficial cells; group III (8-30-3, 77-1, 2-94-2, 3-71-1, and 94-3) was restricted to antigens on the luminal membrane of superficial cells. All antibodies recognized antigenic determinants in fixed paraffin-embedded material and within groups showed a range of staining patterns in other tissues. Studies on sections representing different stages of neoplastic progression showed disruption in the antibody-staining pattern in urothelium and, in all cases, a strong distinct staining of invasive tumor areas and metastatic secondary tumors. Biochemical analysis of the antigens defined at least three antigenic systems, two of which consisted of molecules having Mr of 250,000 and 300,000 as judged by Western blot analysis. Antigenic determinants recognized by some antibodies (3-48-2, 48-1, 3-50-3, 8-30-3, 77-1, and 3-71-1) were shown to be carbohydrate by reactivity with glycolipid fraction and suggest that antibodies within groups recognize different epitopes on the same molecule.