Z-017. An Immunogenic Lipoprotein of Campylobacter jejuni, Is Required for the Adherence to Host Epithelial Cells and Colonization of the Intestinal Tract of Chickens

M. Fukuda, B. Jeon, O. Sahin, Q. Zhang;
Iowa State Univ., Ames, IA.

Bacterial lipoproteins have important functions in bacterial pathogenesis and physiology. In Campylobacter jejuni, a major foodborne pathogen causing gastroenteritis in humans, the majority of lipoproteins have not been functionally characterized. In this work, we identified a three-gene operon (cj0089, cj0090, and cj0091) encoding a cluster of lipoproteins. It was shown that this lipoproteins-encoding operon is regulated by CmeR, a transcriptional regulator repressing the expression of the multidrug efflux pump CmeABC in C. jejuni. In contrast to the regulation of CmeABC, CmeR appears to activate the expression of the lipoprotein genes, and that the regulation is possibly via an indirect mechanism. Analysis of different cellular fractions indicated that Cj0089 was associated with the inner membrane, while Cj0091 was located on the outer membrane. Inactivation of cj0091, but not cj0089, significantly reduced the adherence of C. jejuni to INT 407 cells in vitro, indicating that Cj0091 function as an adhesin. When inoculated into chickens, the Cj0091 mutant also showed a defect in early colonization of the intestinal tract, suggesting that Cj0091 contributes to Campylobacter colonization in vivo. It was also shown in this study that Cj0091 was expressed and immunogenic in chickens that were naturally infected by C. jejuni. These results identify Cj0091 as a new adhesin in C. jejuni and suggest that it may be targeted to reduce Campylobacter colonization in animal hosts.