Innate and adaptive immune mechanisms are effectively induced in ileal Peyer’s patches of Salmonella typhimurium infected pigs

• We experimentally infected pigs with Salmonella typhimurium.
• Laser-capture microdissection was used to isolate Peyer’s patches.
• Gene expression in Peyer’s patches was screened by qPCR and bioinformatic analysis.
• Innate and adaptive immune mechanisms were effectively triggered in infected tissue.
• Peyer’s patches might act differently from mesenteric lymph-nodes upon infection.

In this report we employed laser-capture microdissection (LCM) coupled to qPCR technology and bioinformatic analysis to characterize, for the first time, the response of Peyer’s patches (PP) from orally infected animals to Salmonella typhimurium, in a model of non-typhoidal salmonellosis. Pathogen was highly found in the cytoplasm of phagocytes in PP and differential gene expression analysis indicated an up-regulation of proinflammatory molecules, establishment of a Th1 driven response and triggering of DC and T-cell activity. Furthermore, predictions by bioinformatic analysis pointed to an activation of processes regarding stimulation and maturation of DC, influx of leukocytes in tissue and T lymphocytes priming and differentiation. In short, the approach used in this study proved to be a promising strategy to explore infectious processes. Indeed, it revealed an effective induction of innate and adaptive immune mechanisms in swine PP which appear to be distinct from those observed in mesenteric lymph nodes and closely related to response of gut mucosa.