Impact of gene fliD and virulence plasmid pSEV on the host response by chicken embryo fibroblasts to Salmonella Enteritidis

While Salmonella Enteritidis is the most important serovar of poultry origin in human outbreaks, its complex interaction with avian cells remains less understood. Our previous observations on response of chicken embryo fibroblasts to the wild type strain S. Enteritidis 11 raised the question whether the virulence-defective mutants of this strain lacking flagellin gene fliD,only or both fliD and serovar-specific virulence plasmid pSEV, are inducing altered expression of fibroblast genes. As expected, deletion mutants of fliD and pSEV showed reduced invasiveness and moderate induction of immune genes, but induced a dramatically increased expression of the non-immune gene G0S2. We concluded that chicken fibroblasts prove to be a good model to differentiate host responses by wild type strains and virulence-defective mutants of S. Enteritidis. Our data indicate the importance of flagella and pSEV as key modulators of virulence and of fibroblast response including the modulation of survival genes such as G0S2.