Interleukin-2 (IL-2), discovered over 40 years ago as a T cell growth factor, is a crucial cytokine produced primarily by activated CD4+ T cells. It plays a key role in the proliferation, survival, and function of immune effector cells, regulatory T cells (Tregs), and natural killer (NK) cells, maintaining immune homeostasis. IL-2 is essential for the proliferation of T and B lymphocytes, with its receptor being a heterotrimeric complex shared with IL-4 and IL-7. IL-2-based immunotherapies are currently in clinical trials for various cancers and autoimmune diseases, highlighting its significant role in the immune response to antigenic stimuli.

Abbreviations:

IL-2, T-cell growth factor (TCGF), Lymphokine.