Abstract
Defensins are important antimicrobial effector peptides of the innate immune system,
which provides protection against bacterial infections in the intestine. Salmonella
Choleraesuis and Salmonella Typhimurium are the most commonly isolated serovars in
pig, but disease outcome is dependent on the Salmonella serovar. These infections are a
serious problem for the swine industry and are also posing a major threat to public health
because of Salmonella-related food-borne illnesses in human. To understand the innate
immune response of pigs upon Salmonella infections, we studied the effect of these
Salmonella serovars on defensin gene expression in the porcine ileal epithelial cell line
IPEC-J2. With the use of scanning electron microscopy, we first visualized the surface
characteristics of this cell line, and captured the invasion of Salmonella into the epithelial
cell. Gene expression levels of porcine b-defensin 1 and 2 were both induced upon S.
Typhimurium infection but S. Choleraesuis had no effect. Invasion, adhesion and defensin
susceptibility of both serovars were similar, which could not explain the observed
difference in host response to these Salmonellae. In addition, induction of defensins was
dependent on viability of S. Typhimurium, since Salmonella cell- or secreted components
had no effect on defensin gene expression. These results provide further insight into the
porcine innate immune response towards Salmonella infections, and could partially
explain the different epidemiology of Salmonella infections in pig.
which provides protection against bacterial infections in the intestine. Salmonella
Choleraesuis and Salmonella Typhimurium are the most commonly isolated serovars in
pig, but disease outcome is dependent on the Salmonella serovar. These infections are a
serious problem for the swine industry and are also posing a major threat to public health
because of Salmonella-related food-borne illnesses in human. To understand the innate
immune response of pigs upon Salmonella infections, we studied the effect of these
Salmonella serovars on defensin gene expression in the porcine ileal epithelial cell line
IPEC-J2. With the use of scanning electron microscopy, we first visualized the surface
characteristics of this cell line, and captured the invasion of Salmonella into the epithelial
cell. Gene expression levels of porcine b-defensin 1 and 2 were both induced upon S.
Typhimurium infection but S. Choleraesuis had no effect. Invasion, adhesion and defensin
susceptibility of both serovars were similar, which could not explain the observed
difference in host response to these Salmonellae. In addition, induction of defensins was
dependent on viability of S. Typhimurium, since Salmonella cell- or secreted components
had no effect on defensin gene expression. These results provide further insight into the
porcine innate immune response towards Salmonella infections, and could partially
explain the different epidemiology of Salmonella infections in pig.
| Original language | English |
|---|---|
| Pages (from-to) | 69-75 |
| Number of pages | 7 |
| Journal | Veterinary Microbiology |
| Volume | 136 |
| Publication status | Published - 2009 |
Keywords
- Innate immunity
- Gut
- Antimicrobial peptide
- Pig
- Salmonella
