Reduction of S245A-mutant CXCR3 receptor expression on the cell surface of HEK 293 cells in response to CXCL11 and PMA. (A) The WT CXCR3, S245 to A 3i loop mutation CXCR3-expressing HEK 293, RBL, Jurkat, and YTS cells, were incubated with CXCL11 (1 mg/mL) for 1 hour at 37°C. The cells were then washed, immunostained with anti-CXCR3–specific antibodies, and FACS analyzed. The reduction of cell-surface expression of CXCR3 is shown. (B) The WT CXCR3, S245 to A 3i loop mutation CXCR3, and the double mutant of 332stopΔ37 C-tail truncated and S245 to A 3i loop mutation expressing HEK 293 were incubated with CXCL11 (1 mg/mL) for 1 hour at 37°C. The cells were then washed, immunostained with anti-CXCR3–specific antibodies, and FACS analyzed. The reduction of HEK 293 cell-surface expression of CXCR3 is shown. *P < .05 by ANOVA and Dunnett test for CXCL11- and PMA-induced reduction in cell-surface expression of D37/S245A versus WT. Data are expressed as the means plus or minus SD of 3 independent experiments.