The IL2RB gene, located on human chromosome 22, encodes the Interleukin-2 receptor subunit beta protein. This protein is a key component of the high-affinity receptors for both Interleukin-2 (IL-2) and Interleukin-15 (IL-15). Structurally, it is a single-pass type I membrane protein with an extracellular domain, a transmembrane region, and an intracellular domain containing motifs essential for signaling, primarily through the JAK/STAT pathway ^[1]. Its expression is significant in hematopoietic tissues and is upregulated upon T-cell activation, playing a critical role in the proliferation and differentiation of lymphocytes. The function of the IL-2Rβ chain is to transmit signals from IL-2 or IL-15 binding into the cell, driving immune responses. Consequently, the protein is prominently expressed on immune cells such as T-lymphocytes and Natural Killer (NK) cells, with expression also observed on activated B-lymphocytes ^[2]. Mutations or dysregulation of the IL2RB gene are associated with severe immunodeficiencies (though less commonly than mutations in its partner subunit IL2RG) and are implicated in the pathogenesis of certain leukemias and lymphomas, often due to constitutive activation of its downstream signaling pathways ^[3].

B6-hIL2RB mouse is a humanized model generated using gene editing technology, in which the mouse Il2rb endogenous signal peptide and extracellular domain are replaced with the human IL2RB signal peptide and extracellular domain. This model can be used for studying the pathological mechanisms and therapeutic approaches of immunodeficiencies and certain leukemias and lymphomas, as well as for the development of IL2RB-targeted drugs.