Fig. 2.

MCs control P. aeruginosa numbers in P. aeruginosa-infected skin wounds. MC-deficient mice exhibit reduced bacterial clearance after skin wound infection in vivo and ex vivo. (A) Bacterial load measured as relative fluorescence units (RFU) during skin wound infection of Kit^+/+ mice (n = 9) and Kit^W/Kit^W-v mice (n = 9) assessed by in vivo live imaging using fluorescent bacteria-binding substrate. Data are shown as means ± SEM with pooled from 3 independent experiments analyzed by Mann–Whitney U test. (B) Representative images of infected wounds assessed by luminescence. Kit^W/Kit^W-v mice exhibit a higher bacterial load (red) than Kit^+/+ mice (yellow). (C and D) Colony forming units (CFUs) of skin homogenates normalized to 0.1 g of skin after 24 h of skin wound infection derived from Kit^+/+ mice (n = 7), Kit^W/Kit^W-v mice (n = 9), and Kit^W/Kit^W-v mice engrafted intradermally with bone marrow-derived MCs (MCs → Kit^W/Kit^W-v) (n = 6) (C), Cpa3-Cre; Mcl-1^fl/fl mice (n = 7) and Cpa3-Cre; Mcl-1^+/+ mice (n = 7) (D). Data pooled from 3 independent experiments analyzed by Mann–Whitney U test. (E and F) CFUs of supernatant derived from Kit^+/+ (n = 6) and Kit^W/Kit^W-v (n = 6) skin biopsies after 3 h ex vivo infection with P. aeruginosa (E) and S. aureus (F). Data pooled from 3 independent experiments analyzed by Mann–Whitney U test. (G) Neutrophil numbers (Gr-1^high, CD11b⁺) in infected skin wounds of Kit^+/+ mice (n = 6) and Kit^W/Kit^W-v mice (n = 6) by FACS analysis. Data are expressed as mean per mouse and pooled from 3 independent experiments analyzed by Mann–Whitney U test. (H) Myeloperoxidase activity of skin homogenates normalized to 0.1 g of skin from Kit^+/+ mice (n = 6) and Kit^W/Kit^W-v mice (n = 6). Data are expressed as mean per mouse and pooled from 2 independent experiments analyzed by Mann–Whitney U test. *P < 0.05; **P < 0.01; ***P < 0.001; n.s., not significant; n.d., not detectable.