Sheep and goat production is relevant worldwide, and the emergence or introduction of high-impact diseases in these species can have significant economic consequences

This Cooperative Agreement award from the U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) under the Plant and Animal Disease, Pest Control, and Animal Care Federal Grant Program (CFDA 10.025) provides $238,731 to Oklahoma State University (OSU) from October 1, 2024 to September 30, 2026. The project aims to assess the efficacy of various vaccine adjuvants, including those equivalent to MF59 and AS03, compared to aluminum salts (alum) in eliciting humoral and cellular immune responses against respiratory viruses in sheep and goats. This research aligns with the National Animal Disease Preparedness and Response Program's priorities for advancing more effective sheep and goat vaccines, which is critical for enhancing preparedness against emerging viral threats in these livestock species. The findings from this project will inform the development of improved vaccine formulations and accelerate the vaccine deployment process during disease outbreaks.

Viruses are known for their rapid evolution, and minor genetic changes can lead to viral strains with increased virulence. This has been evident in various livestock-affecting viruses, such as high pathogenic porcine reproductiv e and respiratory syndrome in pigs. Vaccination, biosecurity, and depopulation are essential to address emerging viral threats. Live attenuated or recombinant vaccines often require extended production times. Although quicker and relatively safer, inactivated vaccines may elicit weaker immune responses. Vaccine adjuvants, compounds enhancing the body's immunological response to an antigen, are essential tools in vaccinology, especially for inactivated vaccines. Alum (aluminum salts), the first adjuvant added to vaccines, is widely used in human and animal vaccines. However, alum-adjuvanted vaccines have a t-helper 2 biased response, with weak cellular immune responses. In sheep, alum-based vaccines have resulted in granuloma formation and behavioral changes. Emulsions, like MF59 and AS03, are promising adjuvants for livestock vaccines due to their cost-effectiveness. Both are used in human influenza vaccines and have demonstrated safety and efficacy. While the performance of adjuvants has been more often evaluated in pigs and poultry, there is a significant research GAP in ruminants, especially sheep and goats. Differences in immune systems and physiology mean efficacy in one species may not apply to another. Thus, we aim to assess adjuvants with formulations equivalent to MF59 and AS03, compared to alum, in eliciting humoral and cellular immune responses against respiratory viruses in sheep and goats. Additionally, aiming to further enhance the cellular and humoral responses, these adjuvants will be combined with the TLR9 agonist CPG (cytidine phosphate guanosine oligonucleotide) and a carboxypolymethylene (for instance, the carbopol-971P). This aligns with the national animal disease preparedness and response program's priorities, particularly in advancing sheep and goat vaccines. This project will pave the way for more effective vaccine formulations in these animals, enhancing preparedness for emerging viral threats. Furthermore, the findings from this research effort will significantly bolster the acceleration of vaccine deployment processes, particularly during emergent outbreaks of viral diseases. The research-baked information generated in this project will be essential for governmental agencies, vaccine manufacturers, researchers, veterinarians, and stakeholders committed to sheep and goat production.