Lymphokine receptor-directed therapy: a model for immune intervention in leukemia, autoimmunity, and immunodeficiency.

Activation of resting T cells induces the synthesis of interleukin-2 (IL-2) and expression of its high-affinity receptor that involves both a 55-kDa IL-2 binding peptide identified by the anti-Tac monoclonal antibody and a 75-kDa IL-2 binding peptide associated in a receptor complex. The IL-2 receptor is proving to be an extraordinarily important therapeutic target since it is expressed by the abnormal T cells in patients with certain lymphoid malignancies or autoimmune disorders and in individuals rejecting allografts whereas it is not expressed by normal resting cells. IL-2 receptor directed monoclonal antibodies, genetically engineered humanized antibodies, and antibodies armed with toxins or radionuclides represent novel therapeutic agents for these clinical conditions.