Bone marrow–derived c-kit⁺ progenitors recruit to wounds and give rise to EGFP-PMNs in the presence of S aureus. (A-C) Adoptive transfer of EGFP⁻c-kit⁺ cells from EGFP-lys-mice into C57BL/6 wild-type mice. (A) FACS-sorted EGFP⁻c-kit⁺ cells were labeled with Qtracker 705 and intravenously transferred (5 × 10⁵ cells in 0.1 mL of sterile saline) to C57BL/6 mice whose wounds were treated with either sterile saline or S aureus (1 × 10⁷ CFUs). (B) Emigrated Qtracker 705–labeled EGFP⁻c-kit⁺ cells were detected at 24 hours after transfer in wounds (n = 2 mice in each group). (C) Kinetics of EGFP-PMNs within the S aureus–infected wound after adoptive transfer of EGFP⁻c-kit⁺ cells. *P < .05 vs saline-Gr-1 group. Data are derived from 3-4 mice in each group. (D-E) Ex vivo G-CFU assay of wound cells harvested from EGFP-lys-mice treated with saline or S aureus (1 × 10⁷ CFUs). (D) Three days after wounding, S aureus (1 × 10⁷ CFUs)– or saline-treated skin wounds were collected from EGFP-lys-mice, digested, and plated in methylcellulose medium. Data are from 3 separate experiments and represent mean colony counts from S aureus (n = 5 mice)– and saline (n = 3 mice)–treated wounds analyzed 7 days after plating. *P < .05 vs saline group. GM/GEMM indicates granulocyte-macrophage/granulocyte, erythroid, megakaryocyte, macrophage; G, granulocyte; M, monocyte; and E-BFU, erythroid blast-forming unit. (E) Clockwise from top left, EGFP⁺ colony from S aureus–infected wound, cytospin of cells extracted from an EGFP⁺ G-CFU colony, and representative negative control non-EGFP colony. CFU images are overlays of phase-contrast and fluorescent images taken with a 20× objective (bar represents 50 μm). The cytospin image was taken with a 50× objective (bar represents 10 μm). Data are expressed as means ± SEM.