|Miller, William - Bill|
Submitted to: Infection and Immunity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/27/2009
Publication Date: 7/10/2009
Citation: Flanagan, R.M., Neal-Mckinney, J.M., Dhillon, A.S., Miller, W.G., Konkle, M.E. 2009. Examination of Campylobacter jejuni putative adhesins leads to the identification of a new protein, designated FlpA, required for chicken colonization. Infection and Immunity. 77:2399-2407 Interpretive Summary: The human pathogen Campylobacter jejuni is found often in one of its natural hosts, chickens. Therefore, transmission of C. jejuni is often through consumption of undercooked or improperly handled chicken meat. Proteins called adhesins help C. jejuni adhere to cells that line both the chicken and human gut. Several putative adhesins have been identified in C. jejuni. This study examined the prevalence of these adhesins in approximately 100 C. jejuni strains isolated from human clinical and food animal sources. In addition, the role of these adhesins in attachment to gut cells was determined by constructing strains deficient in the production of a single adhesin. Adherence was determined using chicken cell lines and effects on colonization were determined in chicken assays. All but one of the putative adhesins was found in all of the C. jejuni strains. Some adhesins were found to be important in adherence and some were found to be important in colonization. One adhesin, termed here FlpA played a role in both adherence and chicken colonization.
Technical Abstract: Campylobacter jejuni colonization of chickens is dependent upon surface exposed proteins termed adhesins. Putative C. jejuni adhesins include CadF, CapA, JlpA, MOMP, PEB1, Cj1279c, and Cj1349c. We examined the genetic relatedness of ninety-seven C. jejuni isolates recovered from human, poultry, bovine, swine, ovine, and canine sources by multilocus sequence typing (MLST) and examined their profile of putative adhesin-encoding genes by dot blot hybridization. To assess the individual contribution of each protein in bacteria-host cell adherence, the C. jejuni genes encoding the putative adhesins were disrupted by insertional mutagenesis. The phenotype of each mutant was judged by performing in vitro cell adherence assays with chicken LMH hepatocellular carcinoma epithelial cells and in vivo colonization assays with broiler chicks. MLST analysis indicated that the C. jejuni isolates utilized in this study were genetically diverse. Dot blot hybridization revealed that the C. jejuni genes encoding the putative adhesins, with the exception of capA, were conserved amongst isolates. The C. jejuni CadF, CapA, Cj1279c, and Cj1349c proteins were found to play a significant role in the bacterium’s in vitro adherence to chicken epithelial cells, while CadF, PEB1, and Cj1279c were determined to play a significant role in the bacterium’s in vivo colonization of broiler chicks. Because Cj1279c promotes the binding of C. jejuni to host cells, plays a significant role in C. jejuni colonization of chickens, and harbors fibronectin Type III domains, we have termed the product encoded by the Cj1279c gene FlpA for Fibronectin-like protein A.