Proliferation of T lymphocytes is triggered by the interaction of IL-2 with its specific receptor following T lymphocyte activation. The receptor for IL-2 consists of at least three distinct subunits, the alpha chain (IL-2Ralpha), the beta chain (IL-2Rbeta), and the gamma chain (IL-2Rgamma). Interleukin-2 (lL-2), one of the first lymphokines to be identified, plays a central role in the clonal expansion of activated T lymphocytes (T cells) by interacting with its specific cell surface receptor(IL-2 receptor). Antigen-specific, clonal proliferation of T cells is initiated via a process of signal transduction, wherein the specific interaction of the antigen/MHC molecule and T cell antigen receptor complex (TCR) triggers the expression of IL-2 and its homologous receptor (IL-2R).
