TNFSF18, also known as GITRL (glucocorticoid-induced TNF receptor ligand), binds to its receptor GITR on both effector and regulatory T cells and generates positive costimulatory signals []. GITR is also activated by a GITR ligand called SECTM1A []. The costimulatory effect of GITR activation in T cells has been shown to increase T cell expansion and cytokine production, exacerbate autoimmune/inflammatory diseases, favour tumour rejection, perform viral and parasite clearance, and potentiate immune/inflammatory responses [, ].
