Immunotoxins--theoretical and practical aspects.

The clinical application of immunotoxins is still hampered by a number of unsolved problems. These include difficulties associated with each of the components of the conjugates, i.e., antibody, coupling agent, and cytotoxic drug. Additional problems are caused by the conjugate formation itself. Major obstacles are the lack of data relating to the pharmacokinetics of immunotoxins and their fate after binding to the target cells. This article reviews these problems and indicates possible solutions, including two suggestions for model immunotoxins.