FIG. 1.

Campylobacter inoculation increased the secretion of IL-8 and TNF-α in polarized human intestinal epithelial T84 cells. T84 cells were cultured on transwells until the transepithelial resistance reached 1,400 Ω/cm². C. jejuni 81-176 was inoculated from the apical chamber at an MOI of ∼10 and incubated at 37°C for 0, 4, 6, or 24 h. For the 24-h time point, the cells were washed at 6 h to remove unattached bacteria and cultured in fresh medium for another 18 h. No significant difference was detected between the transepithelial resistance before incubation and that after incubation at any time point. The supernatants from the apical and basolateral chambers were collected separately; the bacteria were removed by centrifugation; and protease inhibitors were added to prevent protein degradation. The concentrations of IL-8 (A) and TNF-α (B) were determined by ELISA. Averages for three independent experiments are shown; error bars, standard deviations. Asterisks represent significant (P < 0.05) differences from control cells that were not inoculated with the bacteria.