title: Characterization of prostate-tissue-directed monoclonal antibody, alpha-Pro 13.
abstract: The alpha-Pro 13-secreting hybridoma was produced by immunizing mice with an equal mixture of PC-3, DU145, and LNCaP established prostatic carcinoma cell lines. The specificity of alpha-Pro 13 monoclonal antibody was evaluated by the criteria of differential binding to cultured cells; differential binding to extracts of malignant prostate, nonmalignant prostate, and malignant and nonmalignant tissues of various histiotypes in solid phase radioimmunoassay; and by immunoperoxidase staining of primary surgical tissues of varied histiotypes. The data generated by multiple assay investigation indicate that alpha-Pro 13 exhibits preferential binding to the ductal epithelium of prostate tissue; immunoperoxidase evaluation indicates a considerable heterogeneity of staining of ductal epithelial cells. The most prevalent cross-reactivity of alpha-Pro 13 monoclonal antibody with non-prostate tissue occurs with blood vessel endothelium of restricted tissues. Electrophoretic analysis of immunoprecipitates from radioiodinated prostatic tumor extracts indicates that the molecule recognized by alpha-Pro 13 is of 120,000 dalton apparent nonreduced molecular weight. Under reducing conditions, the antigen (p40) consists of a major component of 40,000 dalton apparent MW and a minor component of 17,000 dalton MW. p40 has an isoelectric point of 3.5-4.5. The antigen is intrinsically stable on the PC-3 cell surface; its release into spent culture medium is negligible. p40 is also stable upon complexation with alpha-Pro 13 antibody in that it is not shed from the cell surface as an immune complex nor is it endocytosed to any extent as an immune complex.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D000912:Antibodies, Neoplasm / Q000276:immunology; D000918:Antibody Specificity; D002460:Cell Line; D003429:Cross Reactions; D004727:Endothelium / Q000276:immunology; D006801:Humans; D006825:Hybridomas; D007124:Immunoenzyme Techniques; D007526:Isoelectric Point; D008297:Male; D008970:Molecular Weight; D011471:Prostatic Neoplasms / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000912:Antibodies, Neoplasm