PD-1 through asparaginyl endopeptidase regulates FoxP3 Stability in Induced Regulatory T cells

CD4+ T cell differentiation into multiple T helper lineages is critical for optimal adaptive immune responses. This report identified a novel intrinsic mechanism by which PD-1 signaling imparted regulatory phenotype to FoxP3+ Th1 cells (denoted as Tbet+iTregPDL1 cells) and iTregs. Tbet+iTregPDL1 cells were capable of preventing inflammation in murine models of experimental colitis and experimental graft versus host disease. PDL-1 binding to PD-1 imparted regulatory function to Tbet+iTregPDL1 cells and iTregs by specifically downregulating an endolysosomal protease asparaginyl endopeptidase (AEP)

12

Stathopoulou C, Gangaplara A, Mallett G, Flomerfelt FA, Liniany LP, Knight D, Samsel LA, Berlinguer-Palmini R, Yim JJ, Felizardo TC, Eckhaus MA, Edgington-Mitchell L, Martinez-Fabregas J, Zhu J, Fowler DH, van Kasteren SI, Laurence A, Bogyo M, Watts C, Shevach EM, Amarnath S