Re-expression of CXCR2 on the cell membrane.

CXCR2-expressing HEK 293 cells were either not incubated with GCP-2 (control cells) or incubated with 1000 ng/mL GCP-2 at 37°C for 1 hour. The GCP-2–exposed cells were subdivided into 2 groups. One group of cells was washed and stained immediately after exposure to GCP-2 with anti-CXCR2–specific antibodies, as described in “Materials and methods.” The cells of the other group were washed and allowed to recover at 37°C for various intervals, in the presence or absence of 10 μg/mL cycloheximide. The cells were washed and stained with anti-CXCR2-specific antibodies, and subjected to fluorescence-activated cell sorting (FACS) analysis as described in “Materials and methods.” No recovery indicates cells undergoing internalization and no recovery at 37°C; 90 minutes and 4 hours indicate the time of recovery at 37°C. Counts indicates relative cell number; and baseline, cells stained with cell sorter buffer instead of antibodies to CXCR2. A representative experiment of 3 performed is shown.