A Live-Attenuated Equine Influenza Vaccine Stimulates Innate Immunity in Equine Respiratory Epithelial Cell Cultures That Could Provide Protection From Equine Herpesvirus 1.
Authors: Zarski Lila M, Vaala Wendy E, Barnett D Craig, Bain Fairfield T, Soboll Hussey Gisela
Journal: Frontiers in veterinary science
Summary
# Editorial Summary Live-attenuated intranasal influenza vaccination has long been recognised for its ability to trigger robust mucosal immune responses, yet its potential to provide cross-protective benefits against other respiratory pathogens remains underexplored. Zarski and colleagues investigated whether Flu Avert®, administered to primary equine respiratory epithelial cell cultures, could enhance antiviral immunity sufficiently to suppress equine herpesvirus 1 (EHV-1) replication—a particularly important question given EHV-1's capacity to evade host defences through immune modulation. Using high-throughput qPCR and multiplex protein analysis over a 10-day period, the researchers found that Flu Avert treatment induced significant upregulation of key antiviral chemokines (IL-8, CCL2, and CXCL9) beginning at days 5–6 post-vaccination, with a corresponding reduction in both intracellular and extracellular EHV-1 viral titres during this same window. These findings suggest that the innate immune response generated by the live-attenuated influenza vaccine actively counteracts some of EHV-1's immunosuppressive mechanisms at the epithelial level, with optimal protection occurring 5–8 days following vaccination. Whilst this in vitro work is promising for situations where EHV-1 exposure is anticipated, practitioners should await in vivo studies before considering Flu Avert as a standalone prophylactic strategy; nevertheless, the work provides a mechanistic rationale for investigating how mucosal vaccination timing might be optimised in herds facing respiratory disease challenges.
Read the full abstract on PubMed
Practical Takeaways
- •In-vitro data suggests intranasal flu vaccine may offer cross-protective benefits against EHV-1 at the respiratory mucosa by boosting local antiviral immunity; clinical field trials are needed to confirm effectiveness
- •If in-vivo studies support these findings, timing of flu vaccination relative to potential EHV-1 exposure may be important, with optimal protection occurring 5-8 days post-vaccination
- •This approach may be particularly relevant for farms managing EHV-1 risk, though it cannot replace dedicated EHV-1 vaccination strategies currently available
Key Findings
- •Flu Avert intranasal vaccine stimulated innate immune responses in equine respiratory epithelial cells, upregulating IL-8, CCL2, and CXCL9 chemokines at days 5-6 post-treatment
- •Peak chemokine induction at days 5-8 post-Flu Avert treatment coincided with reduced EHV-1 replication in epithelial cell cultures
- •Flu Avert treatment modulated multiple antiviral immune pathways (interferons, cytokines, chemokines) that counteract EHV-1 immune-evasion mechanisms at the airway epithelium