Interleukin-2 receptor intermediate-affinity complex (IL-2Rβγ)

The Interleukin-2 receptor intermediate-affinity complex is a signaling receptor assembly composed of the Interleukin-2 receptor subunit beta (CD122) and the common cytokine receptor gamma chain (CD132). Unlike the high-affinity trimeric receptor, this dimeric complex lacks the alpha subunit (CD25) and is primarily expressed on resting CD8+ effector T cells and natural killer (NK) cells (Waldmann, 2006, Nature Reviews Immunology). Upon binding its ligand, the complex initiates intracellular signaling through the Janus kinase (JAK) 1 and 3 pathways, leading to the phosphorylation of STAT5 and subsequent cellular proliferation and functional activation (Liao et al., 2013, Immunity). This receptor complex has become a focal point in oncology for the development of "biased" or "next-generation" IL-2 therapies. These drugs are engineered to selectively bind the intermediate-affinity complex while avoiding the high-affinity receptor found on regulatory T cells (Tregs), thereby promoting anti-tumor activity without inducing immune suppression (Diab et al., 2020, Cancer Discovery). Clinical applications primarily target advanced solid tumors, such as melanoma and renal cell carcinoma, where robust immune activation is required. However, therapeutic use must be carefully managed to mitigate risks such as vascular leak syndrome and systemic cytokine release (Spolski et al., 2018, Nature Reviews Immunology).

Other names

IL-2R beta-gamma complexCD122/CD132 complexIntermediate-affinity IL-2 receptorIL-2Rβγ

Agonism of the IL-2Rβγ complex to stimulate effector T cells and NK cells while minimizing activation of CD25-expressing regulatory T cells.