Figure 1. mPGES1 modulates T-cell phenotype but not proliferation following immunization with type II collagen (CII).

(A) Adoptive transfer of 3×10⁶ total splenocytes labeled with CFSE from naïve CII-TCR transgenic (CII-TCRTg, Vβ3⁺) WT or mPGES1^−/− donor mice was performed into WT or mPGES1^−/− recipient mice. These recipient mice received 24 hours later either IFA alone or IFA/CII/IFA i.d. and their draining lymph nodes were recovered and analyzed 3 days later. Flow plots show the gating strategy on transferred cells, with CD4⁺Vb3⁺ cells and their corresponding CFSE dilution histograms on the indicated gate below. Graph bars show the percentage of proliferating CD4⁺Vb3⁺ cells for each group of transferred mice (n=1 for IFA only and n=4/group for the CII/IFA groups). (B) Treg and Th17 cell numbers were evaluated in day-10 CII/CFA immunized WT or mPGES1^−/− mice in the indicated organs. Depicted are intracellular IL-17A and IFNγ after 4h of PMA-Ionomycin stimulation (n=8) and (C) FoxP3⁺ proportions within the CD4⁺ cells (n = 6–8) with the corresponding cell numbers on their bar graphs at the right. (D) Freshly isolated splenocytes from day-10 CFA-CII immunized WT or mPGES1^−/− DBA mice (n= 7) were collected and stimulated with 100 mg/ml CII for 4 days, and the presence of IL-17A in the supernatant was measured by ELISA. ** indicates a P value <0.05 using a 2-tailed heteroscedastic Student’s T-test.