Live and Inactivated <i>Salmonella</i> Enteritidis Vaccines: Immune Mechanisms in Broiler Breeders

Abstract

Salmonella is a ubiquitous pathogen which, in addition to causing poultry diseases, has a growing zoonotic impact. It has demanded the implementation of diverse control strategies, in which vaccines play a major role. The understanding of the immune pathways elicited by the different vaccines is important, contributing for the establishment of strong immune correlates of protection, for instance. With the purpose of determining the dynamics of the humoral and cellular immune responses to vaccination, broiler breeders (Cobb Slow) were immunized with live or inactivated vaccines against Salmonella Enteritidis. Lymphocyte and macrophage subsets were analyzed in the peripheral blood by flow cytometry and antigen-specific circulating IgY and mucosal IgA were quantified. The markers analyzed by flow cytometry were CD8/CD28, CD4/TCRVβ1, Kul/ MHC II and Bu-1. Both live and inactivated vaccines induced an increase in the proportion of circulating monocytes (Kul + MHCII + ) in some time points compared to non-vaccinated controls. However, whereas the live vaccine leads to an increase in CD8 − CD28 + and Bu-1 + lymphocytescompared to the control group, the inactivated vaccine prompteda reduction in the percentage of severalleucocyte subsets (Kul − MHCII + , Bu-1 + , CD8 + CD28 + , CD8 − CD28 + , CD4 + TCRVβ1 − , CD4 + TCRVβ1 + , CD4 − TCRVβ1 + ) after the boost dose. Both vaccines induced specific serum IgY and mucosal IgA production; however, the inactivated vaccine stimulated higher titers in a shorter period. These results contribute to the understanding of mechanisms of action of live and inactivated Salmonella vaccines in chickens.

The Simultaneous Administration of a Probiotic or Prebiotic with Live Salmonella Vaccine Improves Growth Performance and Reduces Fecal Shedding of the Bacterium in Salmonella-Challenged Broilers

“…A live lyophilized attenuated vaccine, Salmonella enteritidis, strain Sm24/Rif 12/Ssq, (Elanco Co., Cuxhaven, Germany) is a mutant strain derived from metabolic alterations (Metabolic Drift Mutants) (EFSA, 2004) and cited by Bérto [20]. It was administered via drinking water to the chicks, at the 7th day of age, as one dose, containing at least 10 8 CFU, according to manufacturer instructions.…”

Evaluation of the safety and efficacy of combined Newcastle disease, fowl pox and fowl typhoid vaccine under laboratory condition

“…The 9R strain does not contain the somatic antigen characteristics as the smooth forms of S. Gallinarum due to the loss of some lipopolysaccharide. The change in lipopolysaccharide reduced the virulence of the strain (Bérto et al, 2015;Immerseel et al, 2013).…”