Adhesion of human or mouse neutrophils to P-selectin triggers release of OSM. (A-F) Representative flow cytometric data of intracellular OSM expression in permeabilized CD16b⁺ human neutrophils, CD14-high human monocytes, CD3⁺ human lymphocytes, Ly6G⁺ mouse neutrophils, M-CSFR⁺ mouse monocytes, or CD3⁺ mouse T lymphocytes. The indicated cell population was defined by its specific surface marker and by light scatter. (G) Measurement of OSM in medium or in lysates of human neutrophils after incubation with immobilized human serum albumin (HSA) or human platelet-derived P-selectin with or without shear on a rotary shaker, in the presence or absence of blocking anti-human PSGL-1 mAb PL1 or nonblocking anti–PSGL-1 mAb PL2. (H) Measurement of OSM in medium or in lysates of neutrophils from WT or Selplg^−/− mice after incubation with immobilized mouse CD45-IgM or mouse P-selectin–IgM with or without shear on a rotary shaker. The data in panels A-F are representative of 3 experiments. The data in panels G-H represent the mean ± standard deviation (SD) from 3 experiments. *P < .05; **P < .01.