Efficacy for a New Live Attenuated Salmonella Enteritidis Vaccine Candidate to Reduce Internal Egg Contamination

Abstract

To evaluate the efficacy of a novel attenuated Salmonella Enteritidis (△lon△cpxR) vaccine candidate (JOL919), chickens were immunized through oral and intramuscular routes to reduce egg contamination against S. Enteritidis challenge. Birds were orally immunized with JOL919 on the first day of life and were subsequently boosted in the 6th and 16th weeks through oral (group B) or intramuscular (group C) route, while control birds were unimmunized (group A). The chickens of all groups were challenged intravenously with the virulent S. Enteritidis strain in the 24th week. The immunized groups B and C showed significantly higher plasma IgG and intestinal secretory IgA levels as compared to those of the control group. The lymphocyte proliferation response and CD45(+) CD3(+) T-cell number in the peripheral blood of the groups B and C were significantly increased. In addition, the egg contamination rates were significantly lower in the group B (0%, 10.7% and 0%) and the group C (3.6%, 14.3% and 3.6%) as compared to the group A (28.6%, 42.8% and 28.6%) in the 1st, 2nd and 3rd weeks post-challenge. All animals in the groups B and C showed lower organ lesion scores in the liver and spleen and lower bacterial counts in the liver, spleen and ovary at the 3rd week post-challenge. These results indicate that this vaccine candidate can be an efficient tool for prevention of Salmonella infections by inducing protective humoral and cellular immune responses. In addition, this vaccine did not prevent egg contamination, but did appear to reduce incidence. Booster immunizations, especially via oral administration route, showed an efficient protection against internal egg contamination with S. Enteritidis.

Vaccination against Salmonella Infection: the Mucosal Way

“…In poultry, a vaccine composed of S. Enteritidis and S. Typhimurium SPI-1 mutants cross-protects against the two strains (182) and when a low-dose challenge is administered after oral immunization (183). The S. Enteritidis-based attenuated vaccine JOL919 provides protection early in development by preventing egg contamination (184) via the presence of higher antibody and T cell responses in orally infected chickens.…”

Epidemic characterization and molecular genotyping of Shigella flexneri isolated from calves with diarrhea in Northwest China

“…The majority of Enterobactericeae family bacteria, including Salmonella , E. coli and Shigella spp., the major etiological agent of diarrheal disease, are a global public health burden, particularly in low-income countries [ 1 – 3 ]. Shigella is phylogenetically distinct from several independent E. coli strains and has evolved through convergent evolution [ 4 ].…”

Mucosal Vaccine Development for Veterinary and Aquatic Diseases

“…Veterinary vaccines can also be used to reduce food-borne illness by targeting bacteria that cause no illness or only mild illness in animals, but that can be harmful to humans upon consumption. For example, chicks orally immunized on the first day of life then boosted orally or via the intramuscular route at 6 and 16 weeks of age with a novel attenuated Salmonella Enteridis vaccine candidate, showed significantly higher plasma IgG and intestinal SIgA levels as compared to those in the control group [64]. The lymphocyte proliferation response and CD45 1 CD3 1 T cell number in the peripheral blood of the vaccinated groups were significantly increased.…”