The TSP-4 (P387) variant enhances PMN spreading, αMβ2 surface expression, and clustering. (A) Microscope cover slides were coated with TSP-4 variants for 2 hours at 37°C and coated afterward with 0.5% PVP. PMNs were stimulated with 1 nM PMA and allowed to adhere to the slides for 45 minutes at 37°C. Adherent cells were fixed and stained with biotinylated mAb to αM integrin subunit, followed by incubation with fluorescein isothiocyanate (FITC)–conjugated avidin. Cells were analyzed using a fluorescence microscope (magnification, 1000 ×; × 40/0.7 NA objective). Bar size, 10 μm. (B) Quantification of cell size (area) (left) and brightness intensity (right) was performed using Image Pro-Plus software. A total of 100 cells from 4 blood donors were analyzed, and the data represent mean ± SEM.
