Fig. 7

Effect of CA on the phagocytosis and bactericidal activity of macrophages against S. sonnei. (A-F) J774A.1 macrophages or THP-1 macrophages were pre-treated with CA for 24 h, followed by S. sonnei infection for either 15 min (A, D) or 20 h (B, E). Subsequently, the cells were lysed, and the number of engulfed live S. sonnei was determined using the CFU assay. The CFU count and cell number are denoted in the upper left and lower right corners of the images, respectively. To assess bactericidal activity, the number of killed bacteria was calculated by subtracting the CFU count at 20 h from that at 15 min (C, F). (G-I) J774A.1 macrophages were incubated with CA for 24 h, followed by S. sonnei infection for 21 h. The levels of TNF (G), IL-6 (H) and IL-10 (I) in the supernatants were quantified using ELISA. Data represent the means ± SD from four independent experiments (A-F) or three independent experiments (G-I). Statistical significance was determined by *p < 0.05 and ***p < 0.001 compared to S. sonnei-infected macrophages (G-I) or as indicated