Vibrio vulnificus causes primary septicemia as a result of the consumption of contaminated seafood. The intestinal epithelial layer is the first host barrier encountered by V. vulnificus upon oral intake; however, epithelial translocation (invasion) of V. vulnificus has not been extensively studied. In this study, we investigated in vivo translocation of V. vulnificus using clinical (CMCP6) and environmental isolates (96-11-17M). And we analyzed physiological changes of intestinal epithelium concurrent with bacterial translocation by using polarized HCA-7 transwell culture system. The efficiency of epithelial translocation of 97-11-17M strains was significantly lower than that of pathogenic clinical isolate CMCP6 in a murine ligated ileal loop model. In an oral infection model, the survival rate was reciprocally related with efficacy of in vivo epithelial translocation. These results indicate that efficient translocation of V. vulnificus through intestinal epithelium is highly correlated with successful oral infection. We determined translocation of the bacteria from upper to lower chamber, changes of transepithelial electric resistance (TER) and cytotoxicity of the polarized HCA-7 cells to understand general features of V. vulnificus invasion. Bacterial translocation was accompanied by big decrease of TER (about 90%) and about 50% cytotoxicity of the epithelial cells. Taken together, these results indicate that V. vulnificus actively translocates the epithelium by destruction of epithelium and the efficiency of intestinal invasion by V. vulnificus is critical for successful oral infection. From this result, it is suggested that integrity of intestinal barrier is an important factor for susceptibility to oral infection of V. vulnificus.
Bacteria ; Bacterial Translocation ; Electric Impedance ; Epithelial Cells ; Epithelium ; Intestinal Mucosa ; Seafood ; Sepsis ; Survival Rate ; Vibrio vulnificus* ; Vibrio*

PURPOSE: The house dust mite (HDM) is one of the most important sources of indoor allergens and a significant cause of allergic rhinitis and allergic asthma. Our previous studies demonstrated that Vibrio vulnificus flagellin B (FlaB) plus allergen as a co-treatment mixture improved lung function and inhibited eosinophilic airway inflammation through the Toll-like receptor 5 signaling pathway in an ovalbumin (OVA)- or HDM-induced mouse asthma model. In the present study, we fused the major mite allergen Derp2 to FlaB and compared the therapeutic effects of the Derp2-FlaB fusion protein with those of a mixture of Derp2 and FlaB in a Derp2-induced mouse asthma model. METHODS: BALB/c mice sensitized with Derp2 + HDM were treated with Derp2, a Derp2 plus FlaB (Derp2 + FlaB) mixture, or the Derp2-FlaB fusion protein 3 times at 1-week intervals. Seven days after the final treatment, the mice were challenged intranasally with Derp2, and airway responses and Derp2-specific immune responses were evaluated. RESULTS: The Derp2-FlaB fusion protein was significantly more efficacious in reducing airway hyperresponsiveness, lung eosinophil infiltration, and Derp2-specific IgE than the Derp2 + FlaB mixture. CONCLUSIONS: The Derp2-FlaB fusion protein showed a strong anti-asthma immunomodulatory capacity, leading to the prevention of airway inflammatory responses in a murine disease model through the inhibition of Th2 responses. These findings suggest that the Derp2-FlaB fusion protein would be a promising vaccine candidate for HDM-mediated allergic asthma therapy.
Allergens ; Animals ; Asthma ; Eosinophils ; Flagellin ; Immunoglobulin E ; Inflammation ; Lung ; Mice ; Mites ; Ovalbumin ; Pyroglyphidae ; Rhinitis, Allergic ; Therapeutic Uses ; Toll-Like Receptor 5 ; Vibrio vulnificus