VEGF-A recruits a subset of CD11b⁺/Gr-1⁺/CXCR4^hi neutrophils that contain large amounts of MMP-9. (A-B) Flow cytometric plots from single-cell suspensions of islet grafts in abdominal muscle and muscle from the contralateral side of the linea alba (n = 4). (C-D) Flow cytometric plots from cells harvested from peritoneal lavages where leukocytes were recruited to intraperitoneal (i.p.) injections of either MIP-2 or VEGF-A (n = 5 in each group). Both stimuli recruited similar levels of CD11b/Gr-1⁺ leukocytes (R1 gate). (E-G) The R1 gates from the plots in panels B through D were further analyzed for CXCR4 expression. The histograms represent fluorescence intensity from the CXCR4-mAb (black) and the isotype control-mAb (gray). Numbers in histograms are the mean fluorescence intensities with subtracted isotype intensities. The CXCR4 expression in leukocytes from islet grafts and intraperitoneal VEGF-A is statistically different from the leukocytes recruited to intraperitoneal MIP-2 (P < .05). (H) CD11b/Gr-1 double-positive cells from panels C and D were again gated and analyzed for MMP-9-content and compared with saline control animals (n = 5 in each group). *P < .05, compared with control. (I-J) Total leukocytes from peritoneal lavages were plated in different cell concentrations in the presence of PMA for 1 hour, and the media were then harvested. Images show representative full gels from 1 gelatin zymography experiment. (K) Leukocytes recruited to VEGF-A contained more MMP-9 than leukocytes recruited to MIP-2 in relation to MMP-2 content (n = 3 separate experiments per group).*P < .05.