Replication of equine herpesvirus type 1 in equine dermal cells transfected with Bam HI[G] restriction fragment of EHV-2 genome.

The researchers examined the role of a specific fragment of the equine herpesvirus 2 (EHV-2) genome and its effects on the replication of equine herpesvirus type 1 (EHV-1) in horse skin cells. They found that this genetic fragment increased plaque formation and virus count early in the infection process, but did not influence the overall yield of EHV-1.

Methodology

• The team initially built a library of Bam HI fragments of the EHV-2 genome, which were then inserted into the pcDNA plasmid.
• These constructs were used to transfect equine dermal (ED) cell cultures, which were subsequently passaged five times.
• The researchers then tested for the presence of the plasmids and infected the cultures with EHV-1 at a multiplicity of infection (MOI) of 0.01.

Results

• In cultures transfected with the pcDNA/Bam HI[G] construct, the average number of plaques at 24 hours post infection (p.i.) was about 10 times higher than in non-transfected controls.
• Moreover, virus titers in culture supernatants and in freeze-thawed cells were 4- and 5-fold higher, respectively, than in the non-transfected cultures.
• These differences were only noticed at 24 hours p.i.; by 48 hours p.i., the cultures were fully destroyed and the virus titer was slightly lower in the supernatant of the transfected cells.

Conclusions

• The results indicated that the presence of the Bam HI [G] fragment of the EHV-2 genome stimulates the formation of plaques early in the infection but does not impact the total production of EHV-1 at 48 hours p.i.
• The exact mechanism of this stimulation is currently unclear, and further investigation is required to identify the role of potential EHV-2 proteins encoded by the Bam HI [G] fragment of the EHV genome.