Interleukin-2 receptor complex (IL-2R) (IL-2R)

The Interleukin-2 receptor complex (IL-2R) is a heterotrimeric protein assembly found on the surface of various immune cells, including T lymphocytes and natural killer cells [1, 5]. It consists of three distinct subunits: the alpha chain (CD25), the beta chain (CD122), and the common gamma chain (CD132), which together form a high-affinity binding site for the cytokine interleukin-2 (IL-2) [1, 10]. This complex plays a fundamental role in the immune system by mediating the proliferation, survival, and differentiation of T cells, as well as the maintenance of regulatory T cells essential for self-tolerance [5, 11]. Dysregulation of IL-2R signaling is implicated in several pathological states, including autoimmune diseases, where overactive T cells attack healthy tissue, and various lymphoid malignancies where the receptor is overexpressed [2, 4]. Therapeutically, the IL-2R complex is a major target for both immunosuppressive and immunostimulatory interventions [2, 6]. Monoclonal antibodies like basiliximab and daclizumab bind to the CD25 subunit to block IL-2 signaling, thereby preventing organ transplant rejection and treating certain autoimmune conditions [2, 4]. Conversely, recombinant IL-2 (aldesleukin) is used as an agonist to stimulate anti-tumor immune responses in metastatic melanoma and renal cell carcinoma [5, 11]. Additionally, targeted toxins and antibody-drug conjugates have been developed to selectively eliminate IL-2R-expressing malignant cells [11]. However, modulating this pathway carries risks such as capillary leak syndrome and potential imbalances in immune tolerance [11].

Other names

CD25CD122CD132IL2RTac antigenCommon gamma chainInterleukin-2 receptor subunit alphaInterleukin-2 receptor subunit betaInterleukin-2 receptor subunit gamma

Antagonism of IL-2 binding to the alpha subunit (CD25), agonism of the receptor complex to stimulate immune responses, and targeted delivery of cytotoxic agents to IL-2R-expressing cells [2, 11].