Recombinant Rift Valley fever viruses encoding bluetongue virus (BTV) antigens: Immunity and efficacy studies upon a BTV-4 challenge.

Recombinant Rift Valley fever viruses encoding bluetongue virus (BTV) antigens: Immunity and efficacy studies upon a BTV-4 challenge.

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BackgroundMany ruminant diseases of viral aetiology can be effectively prevented using appropriate vaccination measures.For diseases such as Rift Valley fever (RVF) the long inter-epizootic periods make routine vaccination programs unfeasible.Coupling RVF prophylaxis with seasonal vaccination programmes by means of multivalent vaccine platforms would help to reduce the risk of new RVF outbreaks.Methodology/principal findingsIn this work we generated recombinant attenuated Rift Valley fever yn rating badge viruses (RVFVs) encoding in place of the virulence factor NSs either the VP2 capsid protein or a truncated form of the non-structural NS1 protein of bluetongue virus serotype 4 (BTV-4).

The recombinant viruses were able to carry and express the heterologous BTV genes upon consecutive passages in cell cultures.In murine models, a single immunization was sufficient to protect mice upon RVFV challenge and to elicit a specific immune response against BTV-4 antigens that was fully protective after a BTV-4 boost.In sheep, a natural host for RVFV and BTV, both vaccines proved immunogenic although metabo 15-gauge finish nailer cordless conferred only partial protection after a virulent BTV-4 reassortant Morocco strain challenge.Conclusions/significanceThough additional optimization will be needed to improve the efficacy data against BTV in sheep, our findings warrant further developments of attenuated RVFV as a dual vaccine platform carrying heterologous immune relevant antigens for ruminant diseases in RVF risk areas.