Murine monoclonal antibodies reactive with a variety of androgen independent Dunning rat prostate adenocarcinoma sublines also reactive with human prostate adenocarcinoma

Murine hybridoma-derived monoclonal antibody (MCA) to Dunning rat prostate adenocarcinoma R-3327HIS (androgen independent type) has been produced by fusing P3x63 Ag8-653 myeloma cells with splenocytes of BALB/c mice which were immunized with R-3327HIS tumor cell membranes. One monoclonal antibody designated MCA-R1 (IgG2a subtype) produced an intense immunostaining of various androgen independent Dunning rat prostate tumor sublines (HIS, HIM, HIF, AT-1, AT-2, AT-3, MAT-Lu and MAY-Ly-Lu), but did not stain other tumors of rat origin or normal rat tissues. Marginal immunostaining was detected in the androgen responsive R-3327H and R-3327G tumor subline. Although MCA-R1 antibody did not react with the regressed prostate tumor of R-3327H or R-3327G, it strongly reacted with the relapsed prostate tumor from either R-3327H or R-3327G tumor derived from rats were treated with diethyl stilbestrol (DES) or castration. MCA-R1 antibody also produced a strong cross-reaction with human prostate adenocarcinoma. Like the Dunning rat tumor, human adenocarcinoma exhibited distinct immunostaining patterns with respect to intracellular localization among well differentiated, moderately differentiated and poorly differentiated tumor. Benign prostatic hyperplasia or other normal tissues did not stain. Immunofluorescence, immunoprecipitation, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and radioautographic analysis revealed that the Dunning rat prostate tumor antigen recognized (m.wt. 50 and 120 Kd) by MCA-R1 antibody are localized on both cell surface and in the cytoplasm. This MCA may represent a potential reagent for the study of tumor biology and immunotherapy of prostate tumor.