Antibody Responses to a Reverse Genetics-Derived Bivalent Inactivated Equine Influenza Vaccine in Thoroughbred Horses.

This research article explores the development of a bivalent equine influenza vaccine generated by reverse genetics and compares its efficacy to a commercially available vaccine in Thoroughbred horses. The study confirms that the reverse genetics-derived vaccine can effectively elicit equivalent immune responses to the traditional vaccine, suggesting its potential use in both mono and multivalent vaccines to protect horses against influenza.

Methods and Procedures

• The research focused on the development of a bivalent equine influenza vaccine generated with reverse genetics (RG), a method that allows the creation of viruses possessing specific genes. The team implemented RG in creating two equine influenza viruses.
• They used the genes of A/equine/Ibaraki/1/2007 and A/equine/Yokohama/aq13/2010 strains, mirroring the strains included in the commercially available counterpart for a direct comparison. These custom-made viruses were then inactivated with formalin.
• The hemagglutinin titer of the RG vaccine was regulated to match that of the commercially available (CO) vaccine, which ensured a fair comparison.

Testing and Findings

• In the experiment, sixteen unvaccinated yearlings and thirty-two vaccinated adult horses were involved, divided into groups that received either the RG or CO vaccines. Two doses of primary vaccination were administered four weeks apart to the unvaccinated horses, while a single booster dose was given to the vaccinated horses.
• The research team measured hemagglutination inhibition antibody responses, a common method to evaluate the immunogenicity of influenza vaccines. They found that the antibody responses in both the RG and CO groups were similar, regardless of whether the horse was previously vaccinated or not.

Implications and Conclusions

• The results of the study suggest that a bivalent vaccine developed using reverse genetics can elicit immunity levels equivalent to a traditionally-derived vaccine, which indicates that RG can be an effective tool in creating both mono and multivalent vaccines for horses.
• This discovery redefines the way vaccines for equine influenza can be developed. Given the need for periodic updates of the vaccine strains to maintain their effectiveness, reverse genetics can offer a valuable technique to customize vaccines according to the emerging influenza subtypes.