Impact of DNA Prime/Protein Boost Vaccination against on Immune Responses and Gut Microbiota in Chickens.

is reported to be the leading zoonosis in Europe, and poultry is the main reservoir of Despite all the efforts made, there is still no efficient vaccine to fight this bacterium directly in poultry. Recent studies have reported interactions between the chicken immune system and gut microbiota in response to colonisation. The present study was designed to analyse in more depth the immune responses and caecal microbiota following vaccination with a DNA prime/protein boost flagellin-based vaccine that induces some protection in specific-pathogen-free White Leghorn chickens, as shown previously. These data may help to improve future vaccination protocols against in poultry. Here a vaccinated and a placebo group were challenged by at the age of 19 days. A partial reduction in loads was observed in the vaccinated group. This was accompanied by the production of specific systemic and mucosal antibodies. Transient relatively higher levels of Interleukin-10 and antimicrobial peptide avian β-defensin 10 gene expressions were observed in the vaccinated and placebo groups respectively. The analysis of caecal microbiota revealed the vaccination's impact on its structure and composition. Specifically, levels of operational taxonomic units classified as and increased on day 40.