Venezuelan equine encephalomyelitis virus: concentration, partial purification, inactivation and immunogenicity

Area of Science:

• Virology
• Immunology
• Biochemistry

Background:

• Venezuelan equine encephalomyelitis (VEE) poses a significant threat to equine health.
• Development of effective and safe VEE vaccines is crucial for disease prevention.
• Understanding the purification and inactivation of VEE vaccinal strains is essential for vaccine production.

Purpose of the Study:

• To isolate and purify the Venezuelan equine encephalomyelitis (VEE) TC-84 vaccinal virus.
• To evaluate the immunogenicity and protective efficacy of formalin-inactivated VEE vaccine.
• To characterize the biophysical properties of the VEE TC-84 vaccinal virus.

Main Methods:

• Combined continuous-flow centrifugation and isopycnic banding in sucrose gradients for virus isolation.
• Formalin inactivation of purified VEE virus at 0.05% concentration at 37°C for 24 hours.
• Immunization of horses and guinea pigs followed by challenge with virulent VEE virus.

Main Results:

• The VEE TC-84 vaccinal virus was successfully isolated and purified, with peak infectivity and hemagglutinating activity at a buoyant density of 1.2 g/mL.
• Formalin inactivation effectively eliminated viral infectivity while preserving antigenicity.
• Immunized horses and guinea pigs developed VEE virus-specific antibodies and survived challenge with virulent VEE virus.

Conclusions:

• The purification method effectively concentrated VEE vaccinal virus while removing host cell proteins.
• Formalin-inactivated VEE TC-84 vaccine is immunogenic and protective in animal models.
• This study provides a foundation for the production of safe and effective VEE vaccines.