Fig. 5. Role of PTPN22 in the regulation of ISG expression by TRAF3 in T cells.
(A to C) WT and TRAF3-deficient HuT28 human T cells were pre-treated with 10uM LTV-1 (PTPN22i) or an equivalent concentration of DMSO and then were stimulated with type I IFN (1000 U/ml) for the indicated times in the presence of inhibitor or DMSO. (A) Induction of CXCL10, MX1, and STAT1 transcription, relative to that of a housekeeping gene [−ΔCT = -(CTgene of interest- CT housekeeping)] was determined by RT-qPCR analysis of three biological replicates. (B) Top: Representative Western blotting analysis of the accumulation of STAT1 and MX1 protein over time under the indicated conditions. Bottom: Quantification of the relative amounts of STAT1 and MX1 proteins from six biological replicates. (C) Quantification of the amounts of CXCL10 secreted by the indicated cells 24 hours after treatment with type I IFN was determined by ELISA analysis of samples from eight biological replicates. Graphs include replicates from three (A), six (B), and eight (C) independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 by two-way ANOVA with Sidak’s multiple comparisons test. Error bars represent the SEM.