Transcriptomic analysis of liver indicates novel vaccine to porcine reproductive and respiratory virus promotes homeostasis in T-Cell and inflammatory immune responses compared to commercial vaccine in pigs

Authors: Fleming, Damarius; Miller, Laura; LI, JIUYI - Tennessee State University; Lager, Kelly; VAN GEELEN, ALBERT - Animal And Plant Health Inspection Service (APHIS); SANG, YONGMING - Tennessee State University

Submitted to: Frontiers in Veterinary Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2022
Publication Date: 3/24/2022
Citation: Fleming, D.S., Miller, L.C., Li, J., Lager, K.M., Van Geelen, A., Sang, Y. 2022. Transcriptomic analysis of liver indicates novel vaccine to porcine reproductive and respiratory virus promotes homeostasis in T-Cell and inflammatory immune responses compared to commercial vaccine in pigs. Frontiers in Veterinary Science. 9. Article 791034. https://doi.org/10.3389/fvets.2022.791034.
DOI: https://doi.org/10.3389/fvets.2022.791034

Interpretive Summary: Porcine reproductive and respiratory syndrome (PRRS) is the number one disease problem for US pigs. It is caused by the PRRS virus (PRRSV) for which there are commercially available vaccines. However, the vaccines only give pigs limited protection against the virus due to differences among the PRRSV strains. However, vaccination remains the best available strategy for combatting PRRSV, so we are conducting research into a new vaccine. Pigs given the new vaccine from this study displayed protection from the virus, as well as less inflammation and stress on the liver. There is also evidence that the new vaccine could prove less toxic to pigs since there is less stress on the liver. The results from this study are applicable to many aspects of swine health. The data will help inform veterinarians, immunologists, pharmaceutical companies, and animal scientists of the effectiveness of the new vaccine. Additionally, the results will be of use to commercial pig breeders and pork producers as they continue to improve herd health and food safety.

Technical Abstract: One of the largest impediments for commercial swine production is the presence of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), a devastating RNA virus causing infection that is responsible for over $1 billion in loss in the U.S. annually. The challenge with combating PRRSV is a combination of the effect of an extraordinary rate of mutation, the ability to infect macrophages, and subversion of host immune response through a series of actions leading to both immunomodulation and immune-evasion. Currently there are a handful of commercial vaccines on the market that have been shown to be effective against homologous infections, but struggle against heterologous or mixed strain infections. However, vaccination is the current best strategy for combating PRRSV, making research into new vaccine technology key. To address these issues with PRRSV and host antiviral functions a novel modified-live vaccine (MLV) able to stimulate known antiviral interferons was created and examined for its ability to potentiate effective immunity and better protection. In this study, we examine the gene expression in the liver of pigs vaccinated with our novel vaccine due to the liver’s large role in antiviral responses and vaccine metabolism. Our study indicated that pigs administered the novel vaccine experience homeostatic gene expression consistent with less inflammation and T-cell depletion risk than pigs administered the commercial.