A cytotoxic monoclonal antibody produced from a human urinary bladder carcinoma cell line (TSGH-8301).

A mouse monoclonal antibody, designated 1G3.10, directed against a human urinary bladder cancer cell line TSGH-8301 was generated using the conventional hybridoma technique. It was of the IgG3 subclass with a restricted specificity to bladder cancer and several epithelial cancers, as detected on a panel of various cell lines and tissues by radioimmunoassay and indirect immunofluorescence methods. It also exhibited a strong binding activity to human group A red blood cells, as demonstrated in hemagglutination and absorption tests. Radioimmunoprecipitation and thin-layer chromatography revealed that the antigens recognized by the antibody are a mixture of glycopeptides (M.W. 30, 54, and 108 KD) and glycolipid (retardation factor 0.67-0.83). From a fluorescence activated cell sorter (FACS) study, direct killing of tumor cells by the antibody at a concentration of more than 10 micrograms/ml was observed. This antibody could also mediate both antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) in vitro when tested in a 4-hr 51Cr-release test. These results suggest that the monoclonal antibody 1G3.10 may provide an agent for further immunodiagnosis and the treatment of human bladder cancer.