Reduced tissue colonization of Mycobacterium avium subsp. paratuberculosis in neonatal calves vaccinated with a cocktail of recombinant proteins

Authors: Stabel, Judith; Bannantine, John

Submitted to: Vaccine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/24/2021
Publication Date: 5/7/2021
Citation: Stabel, J.R., Bannantine, J.P. 2021. Reduced tissue colonization of Mycobacterium avium subsp. paratuberculosis in neonatal calves vaccinated with a cocktail of recombinant proteins. Vaccine. https://doi.org/10.1016/j.vaccine.2021.04.051.
DOI: https://doi.org/10.1016/j.vaccine.2021.04.051

Interpretive Summary: Johne's disease is a chronic, debilitating intestinal disorder in cattle characterized by diarrhea, reduced feed intake, weight loss and death. Cattle usually become infected as young calves by ingesting feces containing the causative bacteria. However, symptoms of disease do not usually present themselves until the animals reach 3 to 5 years of age or even older. During this time the animal is infected and may be shedding the organism in its feces without showing any clinical signs of disease. In addition to reduced milk production by these animals, they also present a potential infective threat to the rest of the herd. Little is known how the cow controls this infection in the early stages and what happens to allow full-blown disease to develop. This study presents information on a novel vaccine for paratuberculosis. Calves were either vaccinated or nonvaccinated and then challenged with the bacterium. Immune measures and tissue colonization with the bacteria were determined. Results demonstrated a high level of protection against the bacterium with vaccination. This is helpful for livestock producers who would like to use a vaccine to prevent or reduce infection within their herds, ultimately, reducing the prevalence of paratuberculosis in dairy herds.

Technical Abstract: An increasing prevalence of paratuberculosis supports the need for new efficacious vaccines as an essential management tool. Two separate studies were performed in neonatal calves to evaluate the effectiveness of pooled recombinant Mycobacterium avium subsp. paratuberculosis (MAP) proteins (MAP1087, MAP1204, MAP1272c, MAP2077c) as a potential vaccine. In the first study vaccinated calves were immunized with 400 microg protein cocktail per dose, whereas the second study compared doses of 400 microg and 800 microg of protein cocktail, followed by challenge with live MAP for both vaccinated and nonvaccinated control calves 28 days post-vaccination. At the end of 12 months, fecal shedding and tissue colonization with MAP were significantly reduced for the vaccinated calves compared to control animals. A higher dose of vaccine improved protection, with further reductions of MAP burden. Antigen-specific IFN-gamma responses and serum antibody responses were similar regardless of vaccination, indicating exposure to MAP invoked conventional host immune responses. Host immunity differed due to vaccination, resulting in increased percentages of CD4plus T cells and B cells after stimulation of PBMCs with antigen. Interestingly, gene expression in PBMCs was similar for both control and vaccinated calves except for significant increases in IFN-gamma, IL-12, and IL-17 expression observed in vaccinated calves. Vaccination with a cocktail of immunogenic recombinant MAP proteins was efficacious in reducing the level of infection and fecal shedding of neonatal calves and may be a potential tool for curtailing the spread of Johne’s disease.