We previously reported that the aphB gene mutant of Vibrio vulnificus had significantly impaired motility and adherence to host cells. In this study, we investigated the role of V. vulnificus AphB on the production of interleukin-8 (IL-8), a proinflammatory cytokine, as well as its underlying mechanism in human intestinal epithelial INT-407 cells. The aphB gene mutation significantly reduced the ability of V. vulnificus to stimulate IL-8 production and IL-8 gene promoter activation in INT-407 cells. The V. vulnificus aphB mutant also induced lower levels of NF-kappa B DNA binding activity and NF-kappa B minimal promoter activation than did the wild-type of V. vulnificus. Importantly, the observed reductions in IL-8 production, IL-8 gene promoter activation and NF-kappa B DNA binding activity were significantly restored by complementing the aphB gene into the V. vulnificus aphB mutant. These results indicate that V. vulnificus AphB is involved in the IL-8 production via an NF-kappa B dependent pathway in human intestinal epithelial cells. (C) 2012 Elsevier Inc. All rights reserved.