GARP: a surface molecule of regulatory T cells that is involved in the regulatory function and TGF-β releasing.

There are many molecules that define regulatory T cells (Tregs) phenotypically and functionally. Glycoprotein A repetitions predominant (GARP) is a transmembrane protein containing leucine rich repeats. Recently, GARP is found to express highly on the surface of activated Tregs. The combination of GARP and other surface molecules isolates Tregs with higher purity. Besides, GARP is a cell surface molecule of Tregs that maintains their regulatory function and homeosatsis. GARP has also been proved to promote the activation and secretion of transforming growth factor β (TGF-β). Moreover, its potential value in cancer immunotherapy is also discussed in this work.