Equine herpesvirus 1 (EHV-1) glycoprotein D DNA inoculation in horses with pre-existing EHV-1/EHV-4 antibody.

This research study involves inoculation of horses with a certain type of DNA from the equine herpesvirus 1 (EHV-1) glycoprotein D (gD) to examine its impact on immune responses, specifically in the presence of pre-existing antibodies to equine herpesvirus 4 (EHV-4) and EHV-1.

Research Methodology

• The researchers conducted their study on 20 horses, all of which already had antibodies to EHV-4 while two horse already had antibodies toward EHV-1.
• The horses were subjected to intramuscular inoculation with three varying doses (50, 200, or 500microg) of EHV-1 gD DNA or with 500microg vector DNA.

Study Findings

• In 8 out of the 15 horses, the researchers observed that the inoculation led to an increased level of gD-specific antibodies.
• Nine horses displayed increased virus neutralising (VN) antibody titres compared to the titres present at the inception of the inoculation.

Distinguishing the Antibody Response

• The researchers found that the increase in gD-specific antibodies was not due to a natural infection with either EHV-1 or EHV-4, as suggested by the absence of an increase in gC-specific antibody observed during the 66 weeks of the experiment.
• It was established that the observed increase in EHV-1 gD-specific antibodies primarily denoted an IgGa and IgGb antibody response. This reaction is similar to the isotype profile reported following a natural EHV-1 infection.

In conclusion, this research provides valuable insight into the immune responses induced by the EHV-1 gD DNA, particularly in the presence of pre-existing EHV-1/EHV-4 antibodies in horses. It reaffirms the potential of EHV-1 gD DNA to elicit protective immune responses, making a case for studying its application further in development of potential treatments or vaccines for the equine herpesvirus disease.