Figure 4

Astrocytes enhance neutrophil phagocytosis. A & B. FACS-sorted resting or LPS-primed neutrophils were co-cultured with resting or poly I:C-primed astrocytes at a ratio of 1:1 for 6 hr. FITC-E. coli was added to the co-culture system. All cells were trypsinized and washed with PBS once. Uptake of E. coli by Gr1⁺ neutrophils was quantified by flow cytometry analysis. Numbers indicate the percentage of FITC⁺ neutrophils including neutrophils with E. coli adhesion to the cell surface (small middle peaks in each graph) and neutrophils with engulfed E. coli inside (right peaks in each graph). White bar, neutrophils alone; gray bar, neutrophils co-cultured with resting astrocytes; black bar, neutrophils co-cultured with primed astrocytes (**p < 0.01, vs resting neutrophils alone; +p < 0.05, resting neutrophils plus resting astrocytes vs primed neutrophils plus primed astrocytes. n = 3/bar). C. Resting neutrophils were cultured alone or co-cultured with astrocytes in a transwell plate and phagocytosis of FITC-E. coli was determined by flow cytometry analysis. (*p < 0.05, vs resting neutrophils alone. n = 3/bar).