Immunotoxins up to the present day.

Immunotoxins consist of monoclonal or polyclonal antibodies conjugated to bacterial or plant toxins. The toxins used are typically of the A-B type in which a toxic A chain is coupled to a B chain responsible for cell binding and facilitation of A chain entry into the cytosol. Two broad strategies have been followed: coupling intact toxins, or A chains alone, to antibodies. This review examines current progress in in vitro and in vivo research, including recent clinical studies, concentrating principally on ricin or ricin A chain conjugates. The future role of conjugates using membrane-acting toxins, immunolysins, is also discussed.