[Monoclonal antibodies: therapeutic possibilities and limitations]

Monoclonal antibodies offer a unique possibility for specific recognition of a particular cell type. They can, in principle, be used for immunotherapy, for instance to destroy tumour cells, or to induce immunosuppression by eliminating T lymphocytes. The Fc moiety is essential for the biological effects of the antibody. The interaction of the Fc moiety with natural effector mechanisms (like complement, and Fc receptor positive cells of the monocytic-phagocytic system) is strongly dependent on the subclass and origin (species) of the antibody, and may be a limiting factor for its in vivo use. Furthermore, the binding of a monoclonal antibody may induce antigenic modulation (the selective removal of the antigen from the cell surface) thus making the cell resistant to antibody-mediated elimination. Another phenomenon affecting the therapeutic efficacy of a monoclonal antibody, is the antibody response evoked by the administration of the heterologous immunoglobulin.