Neutrophil granule secretion induced by PAF or LPS results in loss of PSGL-1 from the cell surface.

Purified neutrophils were treated with 10 μM PAF or 100 μg/mL LPS for the indicated times (A) or 60 minutes (B) at 37°C. Some incubations included elastase inhibitor or chymostatin or EDTA. Cells were pelleted and lysed in buffer containing proteinase inhibitors and Triton X-100 as described in “Materials and methods.” Neutrophil lysates were electrophoresed on SDS–polyacrylamide gels, transferred to nitrocellulose, and probed with either polyclonal anti–PSGL-1 N-terminal antibody or PL-2 as indicated. Data are representative of at least 3 experiments with different donors.