Envelope protein E1 as vaccine target for western equine encephalitis virus

Area of Science:

• Virology
• Immunology
• Vaccinology

Background:

• Western equine encephalitis virus (WEEV) poses a significant threat to human and equine health, with no existing vaccines or antiviral treatments for humans.
• Mosquito-borne RNA viruses like WEEV necessitate the development of effective countermeasures.

Purpose of the Study:

• To evaluate a novel HAd5-vectored vaccine expressing the WEEV E1 protein (Ad5-E1) as a potential single-dose WEEV vaccine.
• To assess the efficacy and speed of protection conferred by the Ad5-E1 vaccine against WEEV challenge.

Main Methods:

• Construction of a replication-defective human adenovirus serotype-5 (HAd5) vector expressing the WEEV E1 envelope protein.
• Vaccination of mice with a single dose of the Ad5-E1 vaccine.
• Challenge of vaccinated mice with homologous and heterologous WEEV strains to assess protection and survival.
• Analysis of WEEV-specific T cell responses post-vaccination.

Main Results:

• A single dose of the Ad5-E1 vaccine provided complete protection against lethal challenge with both homologous and heterologous WEEV strains.
• Rapid protection was observed as early as 7 days post-vaccination.
• The Ad5-E1 vaccine induced a robust WEEV-specific T cell response.

Conclusions:

• The WEEV E1 protein delivered via an HAd5 vector is a viable target for vaccine development.
• The Ad5-E1 vaccine demonstrates potential as a single-dose, fast-acting immunization strategy against WEEV.
• Further development of this HAd5-vectored vaccine is warranted for WEEV prevention.