title: VP2-serotyped live-attenuated bluetongue virus without NS3/NS3a expression provides serotype-specific protection and enables DIVA.
abstract: Bluetongue virus (BTV) causes Bluetongue in ruminants and is transmitted by Culicoides biting midges. Vaccination is the most effective measure to control vector borne diseases; however, there are 26 known BTV serotypes showing little cross protection. The BTV serotype is mainly determined by genome segment 2 encoding the VP2 protein. Currently, inactivated and live-attenuated Bluetongue vaccines are available for a limited number of serotypes, but each of these have their specific disadvantages, including the inability to differentiate infected from vaccinated animals (DIVA). BTV non-structural proteins NS3 and NS3a are not essential for virus replication in vitro, but are important for cytopathogenic effect in mammalian cells and for virus release from insect cells in vitro. Recently, we have shown that virulent BTV8 without NS3/NS3a is non-virulent and viremia in sheep is strongly reduced, whereas local in vivo replication leads to seroconversion. Live-attenuated BTV6 without NS3/NS3a expression protected sheep against BTV challenge. Altogether, NS3/NS3a knockout BTV6 is a promising vaccine candidate and has been named Disabled Infectious Single Animal (DISA) vaccine. Here, we show serotype-specific protection in sheep by DISA vaccine in which only genome segment 2 of serotype 8 was exchanged. Similarly, DISA vaccines against other serotypes could be developed, by exchange of only segment 2, and could therefore safely be combined in multi-serotype cocktail vaccines with respect to reassortment between vaccine viruses. Additionally, NS3 antibody responses are raised after natural BTV infection and NS3-based ELISAs are therefore appropriate tools for DIVA testing accompanying the DISA vaccine. To enable DIVA, we developed an experimental NS3 ELISA. Indeed, vaccinated sheep remained negative for NS3 antibodies, whereas seroconversion for NS3 antibodies was associated with viremia after heterologous BTV challenge.
authors.affiliation: Central Veterinary Institute of Wageningen UR (CVI), Department of Virology, P.O. Box 65, 8200 AB, Lelystad, The Netherlands; Department of Infectious Diseases & Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands. Electronic address: femke2.feenstra@wur.nl.
authors.forename: Femke
authors.initials: F
authors.lastname: Feenstra
authors.affiliation: Central Veterinary Institute of Wageningen UR (CVI), Department of Virology, P.O. Box 65, 8200 AB, Lelystad, The Netherlands.
authors.forename: Mieke
authors.initials: M
authors.lastname: Maris-Veldhuis
authors.affiliation: Central Veterinary Institute of Wageningen UR (CVI), Department of Virology, P.O. Box 65, 8200 AB, Lelystad, The Netherlands.
authors.forename: Franz J
authors.initials: FJ
authors.lastname: Daus
authors.affiliation: Central Veterinary Institute of Wageningen UR (CVI), Department of Virology, P.O. Box 65, 8200 AB, Lelystad, The Netherlands.
authors.forename: Mirriam G J
authors.initials: MG
authors.lastname: Tacken
authors.affiliation: Central Veterinary Institute of Wageningen UR (CVI), Department of Virology, P.O. Box 65, 8200 AB, Lelystad, The Netherlands; Department of Infectious Diseases & Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: Rob J M
authors.initials: RJ
authors.lastname: Moormann
authors.affiliation: Central Veterinary Institute of Wageningen UR (CVI), Department of Virology, P.O. Box 65, 8200 AB, Lelystad, The Netherlands.
authors.forename: René G P
authors.initials: RG
authors.lastname: van Gennip
authors.affiliation: Central Veterinary Institute of Wageningen UR (CVI), Department of Virology, P.O. Box 65, 8200 AB, Lelystad, The Netherlands; Department of Biochemistry, Centre for Human Metabonomics, North-West University, South Africa.
authors.forename: Piet A
authors.initials: PA
authors.lastname: van Rijn
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001820:Bluetongue virus / Q000235:genetics / Q000276:immunology*; D036022:Capsid Proteins / Q000235:genetics / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D055786:Gene Knockout Techniques; D059386:Reverse Genetics; D065288:Serogroup; D012756:Sheep; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D022581:Vaccines, Marker / Q000008:administration & dosage / Q000276:immunology; D017361:Viral Nonstructural Proteins / Q000235:genetics* / Q000276:immunology; D014765:Viral Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D036022:Capsid Proteins; C075080:S10 protein, Bluetongue virus; C442520:VP2 protein, Bluetongue virus; D014613:Vaccines, Attenuated; D022581:Vaccines, Marker; D017361:Viral Nonstructural Proteins; D014765:Viral Vaccines
keywords: Bluetongue virus; DISA vaccine; DIVA; NS3; Reverse genetics; Serotype