Regulation of immunity by anti-T-cell antibodies.

Current pharmacologic approaches to immune suppression leave much to be desired. The prevention of allograft rejection and the suppression of autoimmunity generally require treatment with corticosteroids or cytotoxic drugs, or both, which may not be sufficiently effective and which frequently cause serious immediate and long-term complications. With the advent of monoclonal antibody technology, it has become possible to identify and selectively inhibit distinct elements in the immune system that contribute to pathologic immune responses. This achievement has led to new therapeutic strategies that may be safer and more effective than the immunosuppressive therapies currently available. Many of these strategies focus on subsets of T cells because of the critical importance of T cells in immune responses. Monoclonal antibodies directed against CD4 + T cells, T-cell activation antigens, and T-cell receptor families have all shown promise in animal models and, in some cases, in preliminary human trials. The challenge now is to translate this promise into practical new forms of immunosuppressive therapy.