Intestinal epithelial cells rarely tricked by Salmonella’s evasiveness
A study by researchers from SciLifeLab and ETH Zurich, Switzerland, sheds light on the defense mechanisms restricting Salmonella Typhimurium (S. Tm) from disseminating to systemic organs from the intestinal tract, following oral infection.
Inflammasomes – signaling complexes that assemble when host cells detect invading pathogens – can prevent systemic dissemination of bacteria from the intestinal tract. As adapted pathogens, such as Salmonella Typhimurium (S. Tm), have evolved evasion strategies, when, where and how inflammasomes carry out this function has remained unclear.
In a recent study published in Nature Mucosal Immunology, co-led by Mikael Sellin (SciLifeLab/Uppsala University) and colleagues at the ETH Zürich, researchers investigated systemic dissemination of S. Tm and the multilayered host defense that counteracts the invading gut pathogen.
Studying the bacterial population in mice, the researchers could establish that certain types of inflammasomes in intestinal epithelial cells specifically restricted S. Tm’s dissemination from the gut to the draining lymph nodes. In surprising contrast, S. Tm successfully escaped detection by inflammasomes in professional phagocytes. The study points to a central gatekeeper role for intestinal epithelial cells in preventing potentially lethal spread of gut bacteria to sterile organs.