Novel Salmonella typhimurium properties in host-parasite interactions

Inflammatory bowel disease (IBD) comprises different diseases in the gastro intestinal tract in human, of which Crohn's disease (CD) and ulcerative col itis (UC) are the most prominent. A key factor in the etiology of IBD is th e chronic inflammatory process, and a large body of evidence suggests that the transcription factor nuclear factor-kappa B (NF-kappa B) is the key reg ulator of responses determining the clinical inflammatory condition. Recent findings using antisense oligonucleotides provide direct evidence that the p65 subunit of NF-kappa B plays a central role in chronic intestinal infla mmation. It has previously been shown that the Gram negative bacteria Yersi nia pseudotubercolosis targets the eukaryotic signal transduction pathway(s ) that lead to NF-kappa B activation (and thus avoid an anti-bacterial infl ammatory response). In this paper, growth-based selected Salmonella typhimu rium clones have been used to generate a clearer picture of the molecular m echanisms involved in host-parasite interactions. From the results presente d here, S. typhimurium and Y. pseudotubercolosis may use the same mechanism to block NF-kappa B activation, following host cell infection. A new adapt ational feature could also be shown, where a growth-based selected bacteria avoided the normally induced translocation of NF-kappa B in host cells. (C ) 1999 Elsevier Science B.V. All rights reserved.