Monoclonal antibody therapy: "model" experiments with toxin-conjugated antibodies in mice and rats.

The advent of cell fusion techniques for producing monoclonal antibodies has stimulated world-wide effort in the search for antibodies with specificity for neoplastic cells. In parallel, a number of laboratories have attempted to devise ways of attaching cytotoxic agents to antibodies with the aim of generating potent anticancer agents from monoclonal antibodies that exhibit sufficient specificity for Cancer cells. The most successful ploy for arming antibody molecules has been to couple them to highly poisonous toxins such as abrin, from the jequirity bean, and ricin, from the castor bean. Abrin and ricin are glycoproteins comprising two polypeptide subunits, A and B, joined by a disulphide bond. The B-chain binds to galactose-containing molecules which are to be found on most cell surfaces and the A-chain is believed to penetrate the plasma membrane or the membrane of an endocytic vesicle and kill the cell by damaging ribosomes (reviewed in [ W