A Brazilian glycoprotein E-negative bovine herpesvirus type 1.2a (BHV-1.2a) mutant is attenuated for cattle and induces protection against wild-type virus challenge

Abstract

, was designed as a vaccinal strain for differential vaccines, allowing the distinction between vaccinated and naturally infected cattle. In order to determine the safety and efficacy of this candidate vaccine virus, a group of calves was inoculated with 265gE -. The virus was detected in secretions of inoculated calves to lower titres and for a shorter period than the parental virus inoculated in control calves. Twenty one days after inoculation, the calves were challenged with the wild type parental virus. Only mild signs of infection were detected on vaccinated calves, whereas nonvaccinated controls displayed intense rhinotracheitis and shed virus for longer and to higher titres than vaccinated calves. Six months after vaccination, both vaccinated and control groups were subjected to reactivation of potentially latent virus. The mutant 265gE -could not be reactivated from vaccinated calves. The clinical signs observed, following the reactivation of the parental virus, were again much milder on vaccinated than on non-vaccinated calves. Moreover, parental virus shedding was considerably reduced on vaccinated calves at reactivation. In view of its attenuation, immunogenicity and protective effect upon challenge and reactivation with a virulent BHV-1, the mutant 265gE -was shown to be suitable for use as a BHV-1 differential vaccine virus.INDEX TERMS: BHV-1, differential vaccine, gE deletion, IBR.

Efficacy of a gE-deleted, bovine herpesvirus 1 (BoHV-1) inactivated vaccine

“…These results confirm that a significant protection to clinical disease was attained after vaccination. The clinical protection against challenge with wild type virus was comparable to the protection obtained with the attenuated vaccine (Franco et al 2002b). These results are also comparable with those of previous workers with another, similarly built, inactivated gE -virus vaccine (Kaashoek et al 1995).…”

“…Thus, the inactivated preparation was as efficacious as the attenuated recombinant vaccine formulation in reducing virus shedding in nasal and ocular secretions (Franco et al 2002b). Reduction in challenge virus shedding, though not always linked to clinical protection, is important for the reduction of virus circulation within a herd, or between herds (Van Oirschot 1999).…”

“…This virus was named 265gE -and evaluated in vaccination/challenge experiments (Franco et al 2002a). The live 265gE -virus based vaccine significantly reduced clinical signs of disease and virus shedding from vaccinated/challenged calves (Franco et al 2002b). However, inactivated vaccine preparations may be considered safer in some instances, and may be favoured in relation to modified live attenuated virus vaccines.…”

Prokaryotic expression of a truncated form of bovine herpesvirus 1 glycoprotein E (gE) and its use in an ELISA for gE antibodies

“…The virus used for gE cloning was the BoHV-1.2 isolate SV56/90 (Weiblen et al 1992, Silva et al 2007). The viruses used in the characterization of the recombinant proteins were Brazilian BoHV-1 (SV-265 and 265gE-) and BoHV-5 (SV507/99) strains described elsewhere (Franco et al 2002, Silva et al 2007. Escherichia coli strain BL21 (DE3) was used for initial cloning, sequencing and maintenance of DNA fragment.…”

“…Towards the development of DIVA vaccines for use in South America, a gE-deleted BoHV-1 based on a Brazilian BoHV-1 strain has been constructed (Franco et al 2002). In addition, our group recently described the construction of a BoHV-5 strain lacking gE and thymidine kinase (tk) genes (Brum et al 2010b).…”