Selection and characterization of brivudin resistant bovine herpesvirus type 5

Brazilian Journal of Microbiology

Mário Celso Sperotto Brum²  Cyndia Mara Bezerra Dos Santos¹  Rudi Weiblen¹  Eduardo Furtado Flores¹ 

[1] ,Universidade Federal de Santa Maria Centro de Ciências Rurais Programa de Pós-Graduação em Medicina VeterináriaSanta Maria RS ,Brasil

关键词: BoHV-5;    thymidine kinase;    drug resistant;    brivudin;   

DOI  :  10.1590/S1517-83822010000100019

来源: SciELO

【 摘 要 】

Bovine herpesvirus type 5 (BoHV-5) is the agent of meningoencephalitis, an important disease of cattle in South America. The neuropathogenesis of BoHV-5 infection is poorly understood and most previous research focused on the role of envelope glicoproteins in neurovirulence. Thymidine kinase (TK) is a viral enzyme necessary for virus replication in neurons and, therefore, represents a potential target for virus attenuation. The selection and characterization of BoHV-5 variants resistant to the nucleoside analog brivudin (BVDU), which selects TK-defective viruses is here described. Several BVDU-resistant clones were obtained after multiple passages in tissue culture in the presence of BVDU and one clone (BoHV-5/R-27) was further characterized. The selected clone replicated to similar titers and produced plaques with similar size and morphology to those of wild-type virus (SV507/99). The genetic stability of the resistant virus was demonstrated after ten passages in cell culture in the absence of the drug. Moreover, the drug-resistant virus showed reduced virulence in a rabbit model: virus inoculation in four rabbits did not result in disease, in contrast with 75% morbidity (3/4) and 50% mortality (2/2) among rabbits inoculated with the parental virus. These results demonstrate that BoHV-5 is sensitive to BVDU and that drug-resistant mutants can be readily selected upon BVDU treatment. BVDU-resistant mutants, likely defective in TK, retained their ability to replicate in tissue culture yet were attenuated for rabbits. This strategy to obtain TK-defective BoHV-5 may be useful to study the role of TK in BoHV-5 neuropathogenesis and for vaccine development.

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