Immune response to Salmonella infections in vaccinated and non-vaccinated turkeys

Vaccination has been widely used to reduce the Salmonella burden in poultry and subsequently the transmission to humans. Concerning turkey, there is little knowledge on the immune response to colonization and invasion by Salmonella species or about efficacy of vaccination and involved immune mechanisms. In the present study, turkeys were vaccinated at the day of hatch and infected with Salmonella Typhimurium (ST) or Enteritidis (SE) field strains three weeks later. A control group was kept uninfected. After challenge infection, bacterial counts in the cecal content, liver and spleen were determined 7 and 14 days post infection. They were often statistically significantly lower in vaccinated poults than in non-vaccinated ones. Production of iNOS, and the cytokines IL-8, IL-10 and IFN-γ were reduced in vaccinated birds. However, neither the influx of CD4 +, CD8α + and CD28 + cells into cecal mucosa after infection nor the antibody response were statistically significantly altered in vaccinated birds.