Early immune response following Salmonella enterica subspecies enterica serovar Typhimurium infection in porcine jejunal gut loopsFrançois Meurens1, Mustapha Berri1, Gael Auray2, Sandrine Melo1, Benoît Levast1, Isabelle Virlogeux-Payant1, Claire Chevaleyre1, Volker Gerdts2 and Henri Salmon1
1 Institut National de la Recherche Agronomique (INRA), UR1282, Infectiologie Animale et Santé Publique, F-37380 Nouzilly (Tours), France
2 Vaccine and Infectious Disease Organization and Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon S7N 5E3, Saskatchewan, Canada
Received 25 July 2008; accepted 13 October 2008; published online 16 October 2008
Abstract - Salmonella enterica subspecies enterica serovar Typhimurium, commonly called S. Typhimurium, can cause intestinal infections in humans and various animal species such as swine. To analyze the host response to Salmonella infection in the pig we used an in vivo gut loop model, which allows the analysis of multiple immune responses within the same animal. Four jejunal gut-loops were each inoculated with 3 108 cfu of S. Typhimurium in 3 one-month-old piglets and mRNA expressions of various cytokines, chemokines, transcription factors, antimicrobial peptides, toll like and chemokine receptors were assessed by quantitative real-time PCR in the Peyer's patch and the gut wall after 24 h. Several genes such as the newly cloned CCRL1/CCX-CKR were assessed for the first time in the pig at the mRNA level. Pro-inflammatory and T-helper type-1 (Th1) cytokine mRNA were expressed at higher levels in infected compared to non-infected control loops. Similarly, some B cell activation genes, NOD2 and toll like receptor 2 and 4 transcripts were more expressed in both tissues while TLR5 mRNA was down-regulated. Interestingly, CCL25 mRNA expression as well as the mRNA expressions of its receptors CCR9 and CCRL1 were decreased both in the Peyer's patch and gut wall suggesting a potential Salmonella strategy to reduce lymphocyte homing to the intestine. In conclusion, these results provide insight into the porcine innate mucosal immune response to infection with entero-invasive microorganisms such as S. Typhimurium. In the future, this knowledge should help in the development of improved prophylactic and therapeutic approaches against porcine intestinal S. Typhimurium infections.
Key words: Salmonella / Th1 cytokines / pig / CCRL1 / pattern recognition receptor
Corresponding author: Francois.Meurens@tours.inra.fr
© INRA, EDP Sciences 2008