IL-2

Interleukin-2 (IL-2) is a key cytokine regulating T cell proliferation, differentiation, and survival^[1]. Mechanistically, IL-2 signals through the heterotrimeric IL-2 receptor complex, activating the JAK1/3-STAT5 pathway to induce transcription of genes critical for T cell expansion and function^[1]. In disease models, IL-2 has been shown to drive regulatory T cell (Treg) expansion, contributing to immune homeostasis and suppression of autoimmunity, while its dysregulation is implicated in cancer and chronic inflammatory conditions^[1]. Compared with related γ-chain cytokines, IL-2 exhibits unique receptor specificity and distinct downstream signaling kinetics, leading to selective activation of Tregs versus effector T cells^[1]. Experimentally, IL-2 stimulation induces expression and unconventional secretion of IL-32β from T cells, highlighting a functional crosstalk between IL-2 signaling and proinflammatory cytokine networks^[1]. Agonists and inhibitors of IL-2 or its receptor have been utilized to manipulate immune responses, providing platforms for preclinical models of autoimmunity, cancer immunotherapy, and T cell functional studies^[1]. Therefore, IL-2 serves as both a central immunoregulatory factor and a practical tool for experimental modulation of T cell-mediated immunity^[1].