Figure 5

Incubation of neutrophils with MSC-CM increases phagocytosis of S. aureus. The effect of MSC secreted factors on neutrophil phagocytosis was assessed by first incubating mouse neutrophils (derived from peritoneal lavage as noted in Methods), then assessing neutrophil phagocytosis of S. aureus. Following incubation neutrophils were infected with S. aureus at an MOI of 1 for 30 minutes and extracellular bacteria was killed by the addition of gentamycin. Neutrophils were stained with CD11b (green) and S. aureus stained with anti-staph antibody (red). Neutrophils incubated with medium alone (A), resting MSC-CM (B) or activated MSC-CM (C). Image analysis was done using Image J software (NIH). Statistical analysis was performed using way ANOVA and Newman-Keul post test *indicates p < 0.05. Similar results were obtained in two additional experiments.