PGE₂ favors the expression of CCR6 and CCR4 in CD4⁺ T cells. PBMCs were cultured as described in the legend of Figure 1. The cells were harvested after 7 days and submitted to 4-color FACS analysis. (A) Representative histogram of CD4 expression in PBMCs cultured in the absence (thin line) or presence (thick line) of PGE₂ (50 ng/mL). (B) Representative histogram of CCR6, CCR4, and CXCR3 expression (thick line) in CD4⁺ T cells (thin line represents isotype control). (C) Representative dot blot of CCR4 and CXCR3 expression in CD4⁺CCR6⁺ T cells. (D) The bars represent the mean percentage plus or minus SD of CD4 and chemokine receptor expression of 11 distinct individual donors. *Significant differences (P < .01) compared with the nil culture condition by paired Student t test.