Apparent stiffness of neutrophils and distribution of neutrophil F-actin when neutrophils were adherent to 24-hour TNF-α–treated ECs or untreated ECs.

After the TNF-α was washed off, the apparent stiffness of the neutrophils was measured using magnetic twisting cytometry, and F-actin was visualized using rhodamine-phalloidin stain as described in “Materials and methods.” (A) Apparent stiffness of neutrophils when they were adherent to TNF-α–treated ECs (▪) or untreated ECs (■) for the indicated times. (B) F-actin distribution in nonadherent neutrophils. (C) F-actin distribution in neutrophils bound to untreated ECs for 15 minutes. (D) F-actin distribution in neutrophils adherent to 24-hour TNF-α–treated ECs for 15 minutes. The stiffness measurement is presented as mean ± SEM of at least 5 separate experiments. *P < .05 when compared with neutrophils bound to untreated ECs. Scale bars, 2 μm.