The C-terminal regions of the envelope glycoprotein gp2 of equine herpesviruses 1 and 4 are antigenically distinct.

This research investigates differences in the antigen properties of a specific protein present in two equine herpesviruses (EHV-1 and EHV-4), finding that the C-terminal region of EHV-1’s protein is distinct in stimulating an immune response only after an EHV-1-specific infection.

Overview of the Study

• The research focuses on the envelope glycoprotein 2 (gp2), a protein that has only been found in the equid alphaherpesviruses, including EHV-1 and EHV-4.
• There is significant antigenic cross-reactivity, meaning different types of the virus can stimulate the immune system similarly due to shared antigenic properties.

Research Methodology

• The researchers studied the C-terminal cleavage product and the high molecular mass gp2 of EHV-1 and EHV-4, which were affinity purified.
• The team used Western blotting to test for cross-reactivity between EHV-1 and EHV-4.
• They also investigated the antigenic recognition of these proteins by horses naturally infected with either of the two herpesviruses.

Research Findings

• Cross-reactivity was observed for the high molecular mass gp2 of both EHV-1 and EHV-4, which means that these virus strains have the same antigens that stimulate similar immune responses.
• However, the 42kDa EHV-1 gp2 C-terminal cleavage product was only detected by the immune systems of horses with antibodies to EHV-1, meaning only horses that had previously been infected with EHV-1 developed an immune response to this protein.
• This phenomenon indicates that the C-terminal region of EHV-1 gp2 is antigenically distinct from that of EHV-4 gp2.
• This finding was validated using serum samples from adult horses and foals that had shown seroconversion due to EHV-1 infection.

Conclusion

• The study thus provides valuable insight into the antigenic properties of the EHV-1 virus, which could potentially inform research on vaccines or treatments targeted at this virus in horses.