IL-2 mutein (Treg-selective)

Class

Selective regulatory T-cell stimulator

This mechanism targets the interleukin-2 (IL-2) receptor pathway using an engineered version of IL-2, called a 'mutein', designed to selectively expand regulatory T cells (Tregs) rather than activating the broader immune system. IL-2 is a cytokine, a signaling protein that immune cells use to communicate, and it is essential for both effector T-cell activation and Treg maintenance. Tregs are a subset of T cells that suppress excessive immune responses and maintain self-tolerance, the immune system's ability to avoid attacking the body's own tissues. Native IL-2 binds effector and Treg cells with different affinities depending on which receptor subunits are present, and unmodified IL-2 tends to stimulate effector and natural killer cells strongly, which is useful in cancer but counterproductive in autoimmune disease. By altering IL-2's structure, a mutein can be biased toward the receptor configuration found preferentially on Tregs, expanding this suppressive population selectively. This approach is being explored across autoimmune and inflammatory diseases, such as conditions marked by loss of self-tolerance, where restoring or amplifying regulatory immune function could reduce tissue-damaging inflammation without broadly suppressing immunity as conventional immunosuppressants do.