Type-specific L1 virus-like particle-mediated protection of horses from experimental bovine papillomavirus 1-induced pseudo-sarcoid formation is long-lasting.

The research investigates the long-term effects of using the BPV1 L1 virus-like particle (VLP) vaccine in horses, demonstrating its successful protection against experimental tumour development induced by BPV1, even several years after immunization.

Introduction

• This study builds on previous research which found that vaccination with BPV1 L1 virus-like particles (VLPs) was effective in protecting horses against the development of pseudo-sarcoids, a skin disease caused by BPV1 or BPV2 infection.
• Equine sarcoids are common skin tumours that are resistant to many forms of treatment.

Methods

• Researchers conducted a long-term study over five years, assessing the effects of BPV1 L1 VLP vaccine on seven horses.
• These horses were immunized with three different doses of the vaccine, while three other horses, used as control animals, were not vaccinated.
• All horses were then exposed to infectious BPV1 virions via intradermal injection at ten different sites on the neck.
• The number of virions per injection was 106.

Results

• In the vaccinated horses, the challenge with BPV1 didn’t result in any visible lesions, regardless of the dose of the vaccine they received.
• Even though the BPV1-neutralising antibody titers had noticeably decreased over the five-year period, and were below the detection limit in one case, the vaccinated horses remained protected against BPV1-induced pseudo-sarcoids.
• In contrast, the unvaccinated control horses developed pseudo-sarcoids at all the injection sites.

Conclusion

• The study’s findings suggest that vaccination with BPV1 L1 VLPs offers long-lasting protection against BPV1 infection in horses.
• These results are significant given the typically resistant nature of equine sarcoids, hinting at a potential preventative approach to treating this common equine disease.