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Published on: July 11, 2015
Randomized controlled trial comparing the immunogenicity of experimental Salmonella Dublin siderophore receptor
Kristen P Hayman1, Cody Sacquitne1, Angela D Rowson2
1Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA.
Objective:
To describe immune responses following administration of experimental Salmonella Dublin siderophore receptor protein (SRP) vaccines in Holstein heifer calves with adequate passive antibody transfer.
Methods:
Calves were randomly assigned to receive placebo, vaccination with S Dublin SRP in adjuvant A, or vaccination with S Dublin SRP in adjuvant B at 7 ± 3 days of age and 3 weeks later. Before each vaccination, 4 and 8 days after the second vaccination (postvaccination), and 61 to 91 days postvaccination, S Dublin antibody titers were measured. Blood mononuclear cells isolated from blood collected 4 and 8 days postvaccination were stimulated with S Dublin SRP antigen (1 or 5 µg/mL) or positive or negative controls, then analyzed to quantify S Dublin SRP-responsive cells. Cultures of blood mononuclear cells were similarly stimulated to quantify interferon-γ (IFN-γ)-producing and IL-17-producing cells. The trial spanned September 4, 2022, through January 15, 2023.
Results:
78 calves were enrolled. Vaccinates had significantly higher IFN-γ-producing cells and IFN-γ and IL-17 concentrations at 4 and 8 days postvaccination, except IFN-γ concentration at day 4 after stimulation with 1 µg/mL. Vaccinates also had higher S Dublin titers at 8 and 61 to 90 days postvaccination. No differences in health events were noted.
Conclusions:
Vaccination can induce S Dublin SRP-specific humoral and cellular immune responses in Holstein heifer calves.
Clinical Relevance:
Vaccination with SRP vaccines resulted in immune responses that may help mitigate S Dublin infection. Further research is needed to determine whether vaccination will be protective against S Dublin challenge.
