title: Generation of replication-defective virus-based vaccines that confer full protection in sheep against virulent bluetongue virus challenge.
abstract: The reverse genetics technology for bluetongue virus (BTV) has been used in combination with complementing cell lines to recover defective BTV-1 mutants. To generate a potential disabled infectious single cycle (DISC) vaccine strain, we used a reverse genetics system to rescue defective virus strains with large deletions in an essential BTV gene that encodes the VP6 protein (segment S9) of the internal core. Four VP6-deficient BTV-1 mutants were generated by using a complementing cell line that provided the VP6 protein in trans. Characterization of the growth properties of mutant viruses showed that each mutant has the necessary characteristics for a potential vaccine strain: (i) viral protein expression in noncomplementing mammalian cells, (ii) no infectious virus generated in noncomplementing cells, and (iii) efficient replication in the complementing VP6 cell line. Further, a defective BTV-8 strain was made by reassorting the two RNA segments that encode the two outer capsid proteins (VP2 and VP5) of a highly pathogenic BTV-8 with the remaining eight RNA segments of one of the BTV-1 DISC viruses. The protective capabilities of BTV-1 and BTV-8 DISC viruses were assessed in sheep by challenge with specific virulent strains using several assay systems. The data obtained from these studies demonstrated that the DISC viruses are highly protective and could offer a promising alternative to the currently available attenuated and killed virus vaccines and are also compliant as DIVA (differentiating infected from vaccinated animals) vaccines.
authors.affiliation: London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK.
authors.forename: Eiko
authors.initials: E
authors.lastname: Matsuo
authors.forename: Cristina C P
authors.initials: CC
authors.lastname: Celma
authors.forename: Mark
authors.initials: M
authors.lastname: Boyce
authors.forename: Cyril
authors.initials: C
authors.lastname: Viarouge
authors.forename: Corinne
authors.initials: C
authors.lastname: Sailleau
authors.forename: Eric
authors.initials: E
authors.lastname: Dubois
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Bréard
authors.forename: Richard
authors.initials: R
authors.lastname: Thiéry
authors.forename: Stéphan
authors.initials: S
authors.lastname: Zientara
authors.forename: Polly
authors.initials: P
authors.lastname: Roy
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D001819:Bluetongue / Q000517:prevention & control*; D001820:Bluetongue virus / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D018929:Cell Culture Techniques; D003673:Defective Viruses / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D005260:Female; D008297:Male; D016865:Reassortant Viruses / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D012756:Sheep; D014765:Viral Vaccines / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D014766:Viremia / Q000517:prevention & control
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D014765:Viral Vaccines