Figure 3. Reduced phosphorylated ERK1/2 might contribute to S phase arrest in CD4^hiCD25⁺ regulatory T cells.

(A) Flow cytometric analysis of the expression of phosphorylated ERK1/2 in CD4^hiCD25⁺ regulatory T cells generated with no treatment (dotted line), isotype-matched mAb (dashed line), and with anti-TLR5 blocking mAb (solid line). Filled histogram is the staining obtained from isotype-matched mAb control for staining antibody (left panel). Statistical analysis of the MFI of p-ERK1/2 in CD4^hiCD25⁺ regulatory T cells. Data show Mean+SEM, n  = 10. All data shown are representative from five independent experiments (right panel). (B) Statistical analysis of the percentage of CD4^hiCD25⁺ regulatory T cells generated on Day 6 with or without the inhibition of ERK1/2 phosphorylation by PD98059. DMSO treated group is the control for PD98059. Data show Mean+SEM, n  = 6. All results shown are from 3 independent experiments (left panel). Cell cycle analysis of CD4^hiCD25⁺ regulatory T cells generated on Day 6 with or without the inhibition of ERK1/2 phosphorylation by PD98059. DMSO treated group is the control for PD98059. Numbers indicate the percentage of CD4^hiCD25⁺ regulatory T cells in S phase. All results shown are from 3 independent experiments (middle panel). Mean percentage of CD4^hiCD25⁺ regulatory T cells in S phase with the inhibition of ERK1/2 phosphorylation by PD98059. Data show Mean+SEM, n  = 6. All results shown are from 3 independent experiments (right panel). *p<0.05, **p<0.01, ***p<0.001, one way ANOVA with Tukey’s pairwise comparisons.