[Preparation of an anti-human immunotoxin against bladder carcinoma and its in vitro targeting cytotoxicity].

The intact ricin was linked to a monoclonal antibody BD I-1, which recognizes a determinant expressed on two human bladder carcinoma cell lines, BIU-87 and E-J, to form an immunotoxin BD I-1 Ricin. The results of indirect immunofluorescence test, FACS analysis and competition binding assay showed that the binding activity of antibody in this immunotoxin was retained by 80% of the original activity. The in vitro cytotoxicity assay indicated that the immunotoxin in the presence of 0.1 mol/L galactose is potent cytotoxic agent for BIU-87 and E-J cell lines. The immunotoxin BD 1-1-Ricin could kill the target cells BIU-87 and E-J cell lines by 50% at a concentration of 0.00008 mumoI/L and 0.00025 mumol/L respectively. At a concentration of 0.001 mumol/L no apparent cytotoxic activity to human colon carcinoma Lovo cell line was observed.