Evaluation of immunogenicity of enterobactin conjugate vaccine for the control of E. coli mastitis in dairy cows

Authors: ZENG, XIMIN - University Of Tennessee; VIDLUND, JESSICA - University Of Tennessee; GILLESPIE, BARBARA - University Of Tennessee; CAO, LIU - University Of Tennessee; Agga, Getahun; LIN, JUN - University Of Tennessee; KERRO DEGO, OUDESSA - University Of Tennessee

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2023
Publication Date: 5/18/2023
Citation: Zeng, X., Vidlund, J., Gillespie, B., Cao, L., Agga, G.E., Lin, J., Kerro Dego, O. 2023. Evaluation of immunogenicity of enterobactin conjugate vaccine for the control of E. coli mastitis in dairy cows. Journal of Dairy Science. https://doi.org/10.3168/jds.2022-23219.
DOI: https://doi.org/10.3168/jds.2022-23219

Interpretive Summary: Mastitis is the most common disease of dairy cows that is responsible for huge economic losses in dairy industry. Current mastitis control programs when fully applied reduced contagious mastitis pathogens, but less effective against environmental mastitis pathogens such as Escherichia coli. Consequently, environmental mastitis pathogens became a major problem for dairy farms with reduced incidence of contagious mastitis pathogens. The current commercially available E. coli J5 vaccine is not effective to prevent coliform mastitis. Restricting bacterial iron intake by targeting enterobactin (Ent) molecule secreted by the bacteria can be a promising approach for the control E. coli mastitis in dairy cows. The immunogenicity and safety of this Ent targeting vaccine in dairy cows are not evaluated. The objective of this study was to determine immunogenicity and safety of Ent conjugate vaccine in dairy cows. We enrolled twelve Holstein dairy cows in to two Groups of 6 Ent vaccinated and 6 phosphate buffered saline (PBS, pH 7.4) injected control cows. Results from this study showed that the Ent conjugate vaccine induced significantly higher Ent-specific antibodies (especially IgG2) in milk and serum. It is safe for dairy cows, as shown by the absence of local and systemic adverse reactions, no detrimental effects on milk production, and no difference in fecal microbiota structure and diversity between vaccine and control groups. Therefore, our study demonstrated that Ent conjugate vaccine is immunogenic in dairy cows, and it is a promising vaccine to control E. coli mastitis in dairy cows.

Technical Abstract: INTERPRETIVE SUMMARY Mastitis is the most common disease of dairy cows that is responsible for huge economic losses in the dairy industry. Current mastitis control programs when fully applied reduced contagious mastitis pathogens but are less effective against environmental mastitis pathogens such as Escherichia coli. Consequently, environmental mastitis pathogens became a major problem for dairy farms with reduced incidence of contagious mastitis pathogens. The current commercially available E. coli J5 mastitis vaccine is not effective in control of E. coli mastitis. Recently, a nutritional immunity approach, which restricts bacterial iron uptake by targeting enterobactin molecule secreted by the bacteria, can be a promising approach for the control of E. coli mastitis in dairy cows. The immunogenicity and safety of this enterobactin targeting vaccine in dairy cows have not been evaluated. The objective of this study was to determine the immunogenicity and safety of the Ententerobactin conjugate vaccine in dairy cows. We enrolled twelve Holstein dairy cows in two Groups of 6 Enterobactin vaccinated, and 6 phosphate buffered saline (PBS, pH 7.4) injected control cows. Results from this study showed that the entrobactin conjugate vaccine induced significantly higher enterobactin specific antibodies in milk and serum. It appears safe for dairy cows, as shown by the absence of local and systemic adverse reactions, no detrimental effects on milk production, and no difference in the fecal microbiota structure and diversity between vaccinated and unvaccinated control groups. Therefore, our study demonstrated that Ent conjugate vaccine is immunogenic in dairy cows, and it is a promising vaccine to in control of E. coli mastitis in dairy cows.