In Vitro: |
PF-06651600 is a potent JAK3-selective inhibitor which can inhibit the JAK3 kinase activity with an IC50 of 33.1 nM but without activity (IC50>10 000 nM) against JAK1, JAK2, and TYK2. PF-06651600 inhibits the phosphorylation of STAT5 elicited by IL-2, IL-4, IL-7, and IL-15 with IC50 values of 244, 340, 407, and 266 nM, respectively. PF-06651600 also inhibits the phosphorylation of STAT3 elicited by IL-21 with an IC50 of 355 nM. Functional assessment in T-cell differentiation assays demonstrate that PF-06651600 suppresses Th1 and Th17 differentiation as measured by IFNγ, after 5 days under Th1 conditions, and IL-17 production, after 6 days under Th17 conditions, with IC50 values of 30 nM and 167 nM, respectively. PF-06651600 also suppresses Th1 and Th17 function as measured by the inhibition of IFNγ production (IC50=48 nM) and IL-17 production (IC50=269 nM) in cells that have been previously differentiated and rested before being treated with PF-06651600[1]. |