Secreted effector proteins of Salmonella dublin act in concert to induce enteritis

The ability of enteropathogenic salmonellae to recruit inflammatory cells a nd induce secretory responses in the infected ileum is considered to be a m ain feature in Salmonella-induced enteritis, Interactions between the patho gen and intestinal epithelial cells result in a variety of cellular respons es mediating inflammation and fluid secretion. It is becoming apparent that proteins secreted by the Inv-Spa type III secretion system of Salmonella s pp. play a key role in the induction of these responses. We have recently d emonstrated that the SopB effector protein is translocated into eukaryotic cells via a Sip-dependent pathway and mediates inflammation and fluid secre tion in infected ileal mucosa. However, SopB did not appear to be the only effector involved, as inactivation of the sopB gene only partially impaired enteropathogenicity. We suggested that at least some of such protein effec ters are likely to be proteins of the same class as SopB, i.e., secreted ef fector proteins translocated into eukaroyotic cells via a Sip dependent pat hway. In this work, we identify SopD, another secreted protein belonging to the family of Sop effecters of Salmonella dublin. Using the cya reporter s ystem,ve showed that SopD is translocated into eukaroyotic cells, We assess ed the potential involvement of SopD in enteropathogenicity and found that inactivation of sopD has an additive effect in relation to the sopB mutatio n.