DETECTION OF INTERSPECIES CROSS-REACTIVE BLADDER CANCER ASSOCIATED ANTIGENS BY RAT MONOCLONAL ANTIBODIES RAISED AGAINST THE SYNGENEIC RAT BLADDER CANCER

Abstract

A monoclonal antibody termed “RS-11” was obtained from a hybridoma clone established by fusion between P3X63Ag8-U1 mouse myeloma cells and spleen cells of a Wistar rat which was hyperimmune to the same strain rat bladder cancer cells induced by BBN (N-butyl, N-hydroxy-butylnitrosamine). Immunoperoxidase staining of cultured cells showed that RS-11 was reactive to rat, dog and human bladder cancer cell lines as well as various cells except myeloma cells, leukemia cells and erythrocytes. By the immunostaining pattern the RS-11-defined antigen was expressed on the cell surface as well as in the cytoplasm of bladder cancer cells. Immunohistochemical examination of tumor tissues revealed that RS-11 was reactive to rat, dog and human bladder cancer, small part of human testicular cancer, penile cancer and meningioma. It was not reactive to other types of cancer and rat and human normal tissues except part of human pancreatic excretory ducts, renal collecting tubules and basal or middle layer of esophagus, tongue and skin. RS-11 was not reactive to glycolipid fraction extracted from antigen-bearing cells and less reactive to the protease-treated cells than to non-treated cells. This suggested that the antigenic determinant to RS-11 was present on a protein.