Figure 8

IL-8 expression and secretion during Salmonella Typhimurium infection. A Expression of Il-8 mRNA in IPEC-J2 cells following 2 h of infection with MOI 100 of STmWT and STmΔfimH after the third passage in normal oxygen level (dark gray bars) and low oxygen level (light gray bars). Non-infected IPEC-J2 cells were assigned as a calibrator sample, and fold change was measured with unstimulated cells set at 1. Data represent mean ± SD of at least three independent experiments. Triplicate samples were analyzed in each experiment to confirm the accuracy and reproducibility of qPCR. B, C Secretion of IL-8 by IPEC-J2 cells exposed to STmWT and STmΔfimH after the third passage in normal oxygen level (dark gray bars) and low oxygen level (light gray bars). After 2 (B) or 4 (C) h of incubation, secretion of IL-8 was measured by ELISA. Interleukin levels were normalized against unstimulated cells. Data represent mean ± SD of four independent experiments and were analyzed in each experiment to confirm the accuracy and reproducibility of ELISA. Statistical differences between strains were analyzed by one-way ANOVA with Tukey multiple comparison test, presented as geometric means with individual values indicated as dots. ^ns non-significant; *p < 0.05, **p < 0.01; ***p < 0.001.