High molecular weight polypeptide bands specific for equine herpesvirus 4

Area of Science:

• Veterinary Virology
• Equine Infectious Diseases
• Immunology

Background:

• Equine herpesviruses 1 (EHV-1) and 4 (EHV-4) are closely related viruses causing significant disease in horses.
• Differentiating between natural infections of EHV-1 and EHV-4 is challenging due to serological cross-reactivity.
• Accurate diagnosis is essential for effective disease management and control in equine populations.

Purpose of the Study:

• To develop and evaluate serological methods for distinguishing between natural EHV-1 and EHV-4 infections in horses.
• To assess the prevalence of antibodies against EHV-1 and EHV-4 in horse populations with and without a history of EHV-1 abortions.

Main Methods:

• Serum neutralization (SN) assays were performed on horse sera (n=520) collected in 1990 and 1992.
• Immunoblotting techniques were employed using pooled positive sera as probes to detect specific viral antigens.
• Analysis focused on antibody prevalence and detection of specific viral polypeptide bands.

Main Results:

• A significantly higher proportion of horses with a history of EHV-1 abortions (1992 group) exhibited measurable EHV-1 antibodies compared to the naive group (1990).
• Both groups showed high prevalence of EHV-4 antibodies, and no horse possessed antibodies solely against EHV-1.
• Immunoblotting detected high molecular weight polypeptide bands (> 200 kDa) specific to EHV-4, with no bands exclusively specific to EHV-1.

Conclusions:

• Serum neutralization and immunoblotting can aid in differentiating between EHV-1 and EHV-4 infections.
• The presence of EHV-1 antibodies is strongly associated with a history of EHV-1 abortions.
• EHV-4 specific polypeptides were identified, suggesting potential diagnostic markers, although they shared properties with EHV-1 gp2.