Figure 3.

Deficiency in CD4-intrinsic mPGES-1 impairs Teff CD4⁺ cell expansion but enhances Treg localization and RORγt expression in the colonic lamina propria. (A,B) Rag1^−/− recipient mice received a co-transfer of a 1:1 mix of CD45.1⁺ WT (blue) and CD45.2⁺ mPGES-1^−/− (red) Teff cells. Flow cytometric analysis of the (A) mLN and (B) cLP CD4⁺ populations, with representative dot plots indicating intracellular expression of CD45.1 or CD45.2 congenic marker expression together with RORγt. In the cLP plot (B), the shaded box indicates a unique RORγt^hi population of mPGES-1 deficient cells in the cLP. Graphs on the right indicate the proportions and total numbers for each group. (C) Co-transfer of either CD45.1⁺ WT Treg with CD45.2⁺ mPGES-1^−/− Teff cells or CD45.2⁺ mPGES-1^−−/− Treg cells with CD45.1⁺ WT Teff into Rag1^−/− recipients. Transfers were always performed with a 2:1 Teff:Treg ratio. In the cLP, mPGES-1^−/− CD4⁺ T cells are able to acquire higher RORγt expression than WT cells (shaded boxes). These CD4⁺RORγt^hi cells arise from both mPGES-1^−/− Teff cells and mature Treg cells. Graphs on the bottom show the proportions of WT or mPGES-1^−/− Treg cells that are either RORγt⁻ or RORγt⁺ in the mLN or the cLP. **P < 0.05 using in a one-way ANOVA with Welch's correction.