Analysis of V. vulnificus-mediated transcriptional activation of IL-8 promoter constructs in INT-407 cells. (a) Schematic representation of the human IL-8 promoter constructs is as shown, along with AP-1, NF-IL-6 and NF-κB binding sites. The nucleotide sequence numbers for each construct are shown. (b) Transient transfection of INT-407 cells with the IL-8 promoter constructs, followed by infection with V. vulnificus at 1, 10 and 50 MOI for 1 hr. Afterwards the cells were postincubated for 20 hr in the presence of gentamycin (100 µg/ml) and the supernatants were assayed for luciferase activity. The results are expressed as induction fold over the value obtained with the uninfected INT-407 cells transfected with the −144/+44 construct, which was given as an arbitray value of 1. (c) INT-407 cells were transfected with either IL-8 full promoter WT or linker scanning IL-8 promoter mutated at a NF-κB site (IL-8 promoter MT), followed by infection with V. vulnificus at 10 MOI for 1 hr. The data represent the mean ± SE (n = 3). *P < 0·05, relative to an uninfected group incubated with medium alone. **P < 0·05, relative to groups transfected with IL-8 promoter WT at each MOI.