title: The role of the multichain IL-2 receptor complex in the control of normal and malignant T-cell proliferation.
abstract: Antigen-induced activation of resting T cells induces the synthesis of interleukin-2 (IL-2), as well as the expression of specific cell surface receptors for this lymphokine. There are at least two forms of the cellular receptors for IL-2, one with a very high affinity and the other with a lower affinity. We have identified two IL-2 binding peptides, a 55-kd peptide reactive with the anti-Tac monoclonal antibody and a 75-kd non-Tac IL-2 binding peptide. Cell lines bearing either the p55, Tac, or the p75 peptide alone manifested low-affinity IL-2 binding, whereas cell lines bearing both peptides manifested both high- and low-affinity receptors. Fusion of cell membranes from low-affinity IL-2 binding cells bearing the Tac peptide alone with membranes from a cell line bearing the p75 peptide alone generated hybrid membranes bearing high-affinity receptors. We propose a multichain model for the high-affinity IL-2 receptor in which both the p55 Tac and the p75 IL-2 binding peptides are associated in a receptor complex. The p75 peptide is the receptor for IL-2 on large granular lymphocytes and is sufficient for the IL-2 activation of these cells. In contrast to resting T cells, human T-cell lymphotropic virus I-associated adult T-cell leukemia cells constitutively express large numbers of IL-2 receptors. Because IL-2 receptors are present on the malignant T cells but not on normal resting cells, clinical trials have been initiated in which patients with adult T-cell leukemia are being treated with either unmodified or toxin-conjugated forms of anti-Tac monoclonal antibody directed toward this growth factor receptor.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology / Q000627:therapeutic use; D000954:Antigens, Surface; D003001:Cloning, Molecular; D006800:Deltaretrovirus Infections / Q000276:immunology / Q000378:metabolism* / Q000473:pathology* / Q000628:therapy; D005098:Exotoxins / Q000627:therapeutic use; D006801:Humans; D000922:Immunotoxins / Q000627:therapeutic use; D011549:Pseudomonas / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D011971:Receptors, Immunologic / Q000235:genetics / Q000378:metabolism*; D015375:Receptors, Interleukin-2; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D005098:Exotoxins; D000922:Immunotoxins; D011948:Receptors, Antigen, T-Cell; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7