-Galactomannan and Saccharomyces cerevisiae var. boulardii Modulate the Immune Response against Salmonella enterica Serovar Typhimurium in Porcine Intestinal Epithelial and Dendritic Cells

Salmonella enterica serovar Typhimurium is a facultative intracellular pathogen that causes inflammation, necrosis, and diarrhea in pigs, aswell as being an important source of food-borne diseases in humans. Probiotics and prebiotics are promising alternatives to antibiotics to control and prevent intestinal infections. The presentwork investigated a recently developed-galactomannan (GM) prebiotic compared to the proven probiotic Saccharomyces cerevisiae var. boulardii on porcine ileum intestinal epithelial cells (IECs) of the IPI-2I line andmonocyte-derived dendritic cells (DCs) cocultured in vitrowith Salmonella.We observed that both S. cerevisiae var. boulardii andGM inhibited the association of Salmonellawith IECs in vitro. Our data indicated thatGMhas a higher ability than S. cerevisiae var. boulardii to inhibit Salmonella-induced proinflammatorymRNA (cytokines tumor necrosis factor alpha [TNF-], interleukin-1 [IL-1], IL-6, and granulocyte-macrophage colony-stimulating factor [GM-CSF] and chemokinesCCL2, CCL20, andCXCL8) and at protein levels (IL-6 andCXCL8). Additionally,GMand S. cerevisiae var. boulardii induced some effects onDCs that were not observed on IECs:GMand S. cerevisiae var. boulardii showed slight upregulation ofmRNA for TNF-, GM-CSF, and CCR7 receptor on porcinemonocyte-derived dendritic cells (DCs). Indeed, the addition ofGMor S. cerevisiae var. boulardii onDCs coculturedwith Salmonella showedhigher gene expression (mRNA) for TNF-, GM-CSF, andCXCL8 compared to that of the contro