Fig. 4

CD362⁺ UC-hMSCs lose function after passage 3 in E. coli pneumonia. Passage 3 CD362⁺ UC-hMSCs ameliorated the E. coli-induced decrement in arterial oxygenation (a), the increase in wet to dry ratio (b), the decrease in static lung compliance (c) and BAL bacterial load (d) compared to vehicle control. These effects were not observed at any later hMSC passage. All CD362⁺ UC-hMSC passages reduced the total infiltrating leukocyte (e) and neutrophil count (f) in BAL compared to the vehicle control. There was no effect of CD362⁺ UC-hMSCs on BAL IL-1β concentration (h) compared to the vehicle control. Passage 3 CD362⁺ UC-hMSCs ameliorated the E. coli-induced increase in BAL CINC-1 concentration (i) compared to the vehicle control, while passages 3 to 7 decreased IL-6 concentration (j). Abbreviations: vehicle, treatment with vehicle alone; passage, passage number of umbilical cord-derived CD362⁺ hMSC, BAL, bronchoalveolar lavage; IL-1β, interleukin 1 beta; CINC-1, cytokine-induced neutrophil chemoattractant 1; IL-6, interleukin 6. Error bars represent standard deviation. *Significantly (P < 0.05) different from the vehicle control group