Monoclonal antibodies directed to leukocyte differentiation antigens for therapeutic use.

During the past years monoclonal antibodies directed to human leukocyte differentiation antigens have resulted not only in fundamental new knowledge of function and differentiation of leukocyte-populations, but have also turned out to be excellent and new tools for the treatment of lymphoid malignancies. Most widely and successfully monoclonal antibodies directed to T-cell differentiation antigens have been used for immunosuppression in organ transplantation. In the present paper, experimental and clinical data are analyzed which may give information about the criteria for clinical effectivity of distinct monoclonal antibodies. The conclusions clearly show, that not only specificity of an antibody, e.g. recognition of a distinct antigen, but also the recognized epitope, affinity and isotype of an antibody play a crucial role for the biological effectivity of a monoclonal antibody. Clinical success in antibody-therapy will therefore be dependent on the possibilities to alter antibody molecules according to the special clinical situation.