Adaptation of equine herpesvirus 1 to unnatural host led to mutation of the gC resulting in increased susceptibility of the virus to heparin.

The research reveals that equine herpesvirus 1 (EHV-1), when adapted to hosts other than horses, undergoes mutation in glycoprotein C (gC), making it more susceptible to the molecule heparin. The mutation appears to enhance heparin binding, particularly in specific hydrophilic regions of the gC.

Research Study Methodology and Observations

• The research observed initial increased resistance of EHV-1 to heparin. Essentially, even if heparin stopped EHV-1 infection in more abnormal hosts like bovines and hamsters, for the strains that evolved primarily within horse cells, this interaction was found to be less effective.
• Researchers took note of gC of different strains that had been adapted to non-equine cells and identified an increase in affinity for heparin, despite the fact that both gC and another glycoprotein, gB, were observed to bind with this compound, regardless of the strain.

Amino Acid Changes & gC Mutation

• The study identified changes in the amino acid configuration of gC in EHV-1 strains that developed in non-equine cells. The changes occurred in the hydrophilic regions of the glycoprotein, specifically between amino acid residues 92 to 175. This made the structure of the glycoprotein more positively charged or cationic.
• The mutation of the gC of EHV-1, which took place as the virus adapted to the unnatural (non-equine) hosts, resulted in not just a change in its properties, but also in its susceptibility to heparin. This implies that the mutation made the virus more prone to treatment by the compound.

Implications of Findings

• The research findings suggest that the hydrophilic regions of glycoprotein C are potentially responsible for binding to heparin. This implies a potentially significant aim for future research in understanding and combating strains of the EHV-1 virus, by exposing non-equine strains to heparin.
• However, caution must be exercised by future researchers in terms of verifying the role of other glycoproteins, such as gB, in the process of heparin binding. The overall process of EHV-1 susceptibility to heparin in non-equine hosts is likely complex and involves the cooperation of multiple viral proteins.