Evaluation of the effects of small interfering RNAs on in vitro replication of feline herpesvirus-1

To evaluate the ability of 5 small interfering RNAs (siRNAs) targeting mRNA of the feline herpesvirus-1 (FHV-1) DNA polymerase gene to reduce in vitro viral replication and gene expression of FHV-1, to evaluate combinations of these siRNAs with siRNAs that target the glycoprotein D gene of FHV-1, and to determine the combination or combinations of siRNAs that yield the greatest inhibition of in vitro viral replication. Cultured Crandell-Rees feline kidney (CRFK) cells. CRFK cells were transfected with siRNAs designed to target mRNA of the FHV-1 DNA polymerase gene. Effective treatment was determined by quantification of the inhibition of mRNA available for DNA polymerase translation, viral protein production, and viral replication. Combinations of 2 siRNAs that target mRNA of the FHV-1 DNA polymerase gene and 2 siRNAs that target the mRNA of the essential FHV-1 glycoprotein D gene were evaluated for the ability to inhibit viral replication. Verified by a reduction in viral gene expression, 2 of the 5 siRNAs designed to target mRNA of the FHV-1 DNA polymerase gene significantly suppressed viral replication. Two combinations of siRNAs that target mRNA of the FHV-1 DNA polymerase gene, the FHV-1 glycoprotein D gene, or both also significantly suppressed viral replication. Combinations of siRNAs that target mRNA of the FHV-1 DNA polymerase gene, FHV-1 glycoprotein D gene, or both could potentially be used as a treatment for the prevention of clinical disease associated with FHV-1 infection.