title: A p50 surface antigen restricted to human urinary bladder carcinomas and B lymphocytes.
abstract: We have previously described the derivation of a monoclonal antibody, S2C6, to a novel 50 Kdalton antigen associated with human urinary bladder carcinoma. No reactions were obtained with carcinomas of unrelated origin or with normal urothelial cells. However, the antibody also reacted with a similar antigen on some cell lines of B lymphocyte origin. Using large panels of target cells we have now shown that this reactivity was entirely restricted to cells of the B lineage within the haematopoietic system. As opposed to its apparent restriction to malignant cells of the urothelium, the S2C6 antigen was expressed by normal B lymphocytes as well as by many malignant B cells (chronic lymphocytic leukaemia, hairy cell leukaemia and immunocytoma). Pre-B cells derived from acute lymphocytic leukaemia and plasma cells from multiple myeloma lacked the antigen. Expression was significantly enhanced on cultured B cells from Burkitt lymphomas and on Epstein-Barr virus-transformed lymphoblastoid cell lines including those of the pre-B phenotype derived from fetal bone marrow. As judged from the molecular size and the distribution pattern displayed by the S2C6 antigen it appears to be distinct from other B cell antigens previously described. A possible relation of the S2C6 antigen to a receptor for B cell growth factors is discussed.
mesh_terms: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm / Q000032:analysis*; D000954:Antigens, Surface / Q000032:analysis*; D001402:B-Lymphocytes / Q000276:immunology*; D001773:Blood Cells / Q000276:immunology; D002277:Carcinoma / Q000276:immunology*; D002472:Cell Transformation, Viral; D004854:Herpesvirus 4, Human; D006801:Humans; D014066:Palatine Tonsil / Q000276:immunology; D013154:Spleen / Q000276:immunology; D013950:Thymus Gland / Q000276:immunology; D001749:Urinary Bladder Neoplasms / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D000954:Antigens, Surface