Les sérotypes de Salmonella induisent différentes interactions cellulaires et moléculaires avec les cellules épithéliales intestinales porcines IPEC-1

The ability of Salmonella serotypes to infect orally a given host and induce pathology relies on their cellular and molecular interactions with the intestinal epithelium. In pigs, the serotype S. Choleraesuis induces septicemia while S. Typhimurium induces gastroenteritis or an asymptomatic carrier state of the bacteria. S. Typhisuis, a serovar rarely studied, is able to cause hemorrhagic diarrhea and colon inflammation. An in vitro approach was used to establish a correlation between the capacity of different Salmonella serotypes to adhere, invade and induce an immune response depending on the porcine intestinal epithelial cells IPEC-1. To this end, S.Choleraesuis, S. Typhimurium and S. Typhisuis were evaluated using this in vitro cellular model in comparison with S. Dublin andS.Gallinarum, two host-specific of cattle and poultry respectively. We have shown that with S. Typhimurium and S. Choleraesuis, the invasion percentage of non-polarized IPEC-1 cells was higher than that obtained with S. Typhisuis, S. Dublin or S. Gallinarum.In contrast, S. Typhisuis invaded successfully polarized IPEC-1 cells as well as S. Choleraesuis and S. Typhimurium but unlike S.Gallinarum or S. Dublin. The analysis of the immune response induction, using RT-qPCR, showed a significant increase of inflammatorycytokine expression such as IL-8, TNF alpha IL1 alpha or IL1 beta CCL20 and CCL25 chemokines and TLR4 receptor in polarized IPEC-1 cells infectedwith S. Typhimurium and S. Typhisuis serotypes. Comparatively, S. Choleraesuis infection did not induce any change in the expressionof these mediators. Thus, the first cell interaction steps with polarized IPEC-1 are able to distinguish serotypes based on their targetspecies whereas induction of the immune response would differentiate a pig’s serotypes according to their pathogenesis.