Deletion of the thymidine kinase gene attenuates Caprine alphaherpesvirus 1 in goats.

Abstract

Caprine alphaherpesvirus 1 (CpHV-1) is a pathogen associated with systemic infection and respiratory disease in kids and subclinical infection or reproductive failure and abortions in adult goats. The enzyme thymidine kinase (TK) is an important viral product involved in nucleotide synthesis. This property makes the tk gene a common target for herpesvirus attenuation. Here we deleted the tk gene of a CpHV-1 isolate and characterized the recombinant CpHV-1ΔTKin vitro and in vivo. In vitro characterization revealed that the recombinant CpHV-1ΔTK replicated to similar titers and produced plaques of similar size to the parental CpHV-1 strain in BT and CRIB cell lines. Upon intranasal inoculation of young goats, the parental virus replicated more efficiently and for a longer period than the recombinant virus. In addition, infection with the parental virus resulted in mild systemic and respiratory signs whereas the kids inoculated with the recombinant CpHV-1ΔTK virus remained healthy. Goats inoculated with the parental virus also developed higher neutralizing antibody titers when compared to CpHV-1ΔTK inoculated animals. Dexamethasone (Dx) administration on days 35-39 post-inoculation did not result in virus shedding in nasal secretions, indicating lack of reactivation from latency. However, viral DNA was detected in the trigeminal ganglia of animals euthanized at 14 days post-Dx, indicating that both viruses successfully established latent infection. Our results show that the recombinant CpHV-1ΔTK presents an attenuated phenotype when compared to the parental virus, and hence may represent a promising vaccine candidate to prevent CpHV-1 disease in goats.

• Authors: Jéssica Caroline Gomes Noll, Lok Raj Joshi, Gabriela Mansano do Nascimento, Maureen Hoch Vieira Fernandes, Bishwas Sharma, Eduardo Furtado Flores, Diego Gustavo Diel
• Journal: Veterinary microbiology (Vet Microbiol) Vol. 237 Pg. 108370 (Oct 2019) ISSN: 1873-2542 [Electronic] Netherlands
• PMID: 31585643 (Publication Type: Journal Article)
• Copyright: Copyright © 2019 Elsevier B.V. All rights reserved.

Chemical References

• DNA, Viral
• Viral Proteins
• Dexamethasone
• Thymidine Kinase

Topics

• Alphaherpesvirinae (genetics, pathogenicity)
• Animals
• Cattle
• Cell Line
• DNA, Viral (isolation & purification)
• Dexamethasone (pharmacology)
• Gene Deletion
• Gene Expression Regulation, Enzymologic
• Gene Expression Regulation, Viral
• Goat Diseases (virology)
• Goats
• Mucus (virology)
• Thymidine Kinase (genetics)
• Viral Proteins
• Virus Shedding