AUTHOR=Purdie Auriol C. , Plain Karren M. , Pooley Hannah , Begg Douglas J. , de Silva Kumudika , Whittington Richard J. 

TITLE=Correlates of vaccine protection against Mycobacterium avium sub-species paratuberculosis infection revealed in a transcriptomic study of responses in Gudair® vaccinated sheep

JOURNAL=Frontiers in Veterinary Science

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2022.1004237

DOI=10.3389/fvets.2022.1004237

ISSN=2297-1769

ABSTRACT=A critical hindrance in the development of effective vaccine strategies to combat infectious disease is an understanding of the protective correlates of immunity and of host factors involved in a successful adaptive immune response. Often vaccine formulations are developed empirically, with little or no understanding of the underlying immunological mechanisms by which they induce protective immunity. Gudair® is a widely used vaccine in sheep and goats for controlling spread of Mycobacterium avium sub-species paratuberculosis (MAP) infections and reduces mortality by up to 90%. Here, using an experimental infection model in sheep, we have utilised a transcriptomics approach to identify gene expression changes in vaccinated, MAP-exposed Merino sheep with a protective response in comparison to those vaccinated animals that failed to develop immunity to MAP infection. This methodology facilitated an overview of gene-associated functional pathway adaptations using an in-silico analysis approach.  Most significantly, we have identified a set of genes induced in the vaccine-protected animals and confirmed stability of expression in samples obtained from naturally exposed commercially maintained sheep. We propose these genes as correlates of vaccine induced protection.