Targeting Human IL-2 Receptors for Diagnosis and Therapy

Abstract

The high-affinity interleukin-2 receptor (IL-2R) is a multichain receptor with at least three IL-2 binding chains: IL-2Rα (55 kDa) bound by the monoclonal antibody anti-Tac, IL-2Rβ (75 kDa) and IL-2rγ (64 kDa). The IL-2Rα also exists as a naturally occurring soluble molecule (sIL-2Rα). We target the IL-2R for immune intervention since resting normal cells do not express the high-affinity IL-2R, whereas this receptor is on some cells in certain lymphoid neoplasias, select autoimmune disorders, and in individuals rejecting organ allografts. Treatments have included unmodified murine anti-Tac and radioisotopes conjugated to murine anti-Tac. Our emerging understanding of the IL-2R system continues to open possibilities for more specific immune intervention.