VP7 from African horse sickness virus serotype 9 protects mice against a lethal, heterologous serotype challenge
An established mouse model system was used to evaluate the effectiveness of the major outer core protein VP7 of African horse sickness virus (AHSV) serotype 9 as a subunit vaccine. Balb C mice were immunised with VP7 crystals purified from AHSV infected BHK cells. In groups of mice, each of which was immunised with ≥ 1.5 µg of the protein in Freund’s adjuvant, ≥ 80% of mice survived challenge with a virulent strain of a heterologous AHSV serotype (AHSV 7), that killed ≥ 80% of the mice in the uninoculated control groups. This level of protection was significantly greater than that observed in mice inoculated with equivalent amounts of either denatured VP7 (50% survival), or GST/VP7 fusion protein (50–70% survival), or which were vaccinated with AHSV 9 (40–50% survival). The VP7 protein folding, or its assembly into crystals, are thought to play some role in the effectiveness of the protective response observed. Titres of circulating antibodies against AHSV VP7 were determined by competitive ELISA but did not appear to correlate with the levels of protection observed. Passive transfer of these antibodies to syngeneic recipients also failed to protect Balb C mice from the AHSV 7 challenge. The observed protection is therefore unlikely to be due to an antibody mediated immune response.
KeywordsSubunit Vaccine Competitive ELISA Virus Serotype Bluetongue Virus Single Inoculation
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- 2.Angove HL, Wade-Evans AM, Burroughs JN, Mertens PPC, Parkhouse RME, Takamatsu H (1998) Immunodominant helper T-cell epitopes recognised by sheep are arranged as a cluster in the amino-acid sequence 202–253 of outer capsid protein VP2 from bluetongue virus serotype 1 from South Africa (manuscript in preparation)Google Scholar
- 8.Holmes IH, Boccardo G, Estes MK, Furuichi MK, Hoshino Y, Joklik WK, McCrae M, Mertens PPC, Milne RG, Samal KSK, Shikata E, Winton JR, Uyeda I (1995) Family Reoviridae. In: Murphy FA, Fauquet CM, Bishop DHL, Ghabrial SA, Jarvis AW, Martelli GP, Mayo MA, Summers MD (eds) Virus Taxonomy. Classification and Nomenclature of Viruses. Sixth Report of the International Committee on Taxonomy of Viruses. Springer, Wien New York, pp 208–237 (Arch Virol [Suppl] 10)Google Scholar
- 9.House JA (1998) Future international management of African horse sickness vaccines. In: Mellor PS, Baylis M, Hamblin C, Calisher CH, Mertens PPC (eds) African horse sickness. Springer, Wien New York (Arch Virol [Suppl] 14)Google Scholar
- 10.Howell PG (1962) The isolation and identification of further antigenic types of African horse sickness virus. Onderstepoort J Vet Res 29: 139–149Google Scholar
- 13.Martin LA, Meyer AJ, O’Hara RS, Fu H, Knowles NJ, Mertens PPC (1998) Phylogenetic analysis of African horse sickness virus genome segment 10: sequence variation involved in virus release and virulence characteristics. In: Mellor PS, Baylis M, Hamblin C, Calisher CH, Mertens PPC (eds) African horse sickness. Springer, Wien New York (Arch Virol [Suppl] 14)Google Scholar
- 15.McIntosh BM (1958) Immunological types of horse sickness virus and their significance in immunisation. Onderstepoort J Vet Res 27: 465–538Google Scholar
- 17.O’Hara RS (1994) Identification of the genome segments and proteins controlling the virulence of African horse sickness virus. Thesis submitted in part for the degree of doctor of Philosophy, University of ReadingGoogle Scholar
- 18.O’Hara RS, Meyer AJ, Pullen L, Martin LA, Mertens PPC (1998) Development of a mouse model system and identification of the individual genome segments of African horse sickness virus serotypes 3 and 8 involved in determination of virulence. In: Mellor PS, Baylis M, Hamblin C, Calisher CH, Mertens PPC (eds) African horse sickness. Springer, Wien New York, pp 259–279 (Arch Virol [Suppl] 14)Google Scholar
- 19.Roy P (1995) Towards the control of African horse sickness by recombinant technology. In: Nakajima H, Plowright W (eds) Equine infectious diseases VII (Proceedings of the Seventh International Conference). R&W Publications, Newmarket, pp 65–70Google Scholar
- 21.Taylor MB, van der Meyden CH, Erasmus BJ, Reid RR, Labuschagne JH, Dreyer L, Prozesky OW (1992) Encephalitis and chorioretinitis associated with neurotropic African horse sickness virus infection in laboratory workers. Part IV. Experimental infection of the veruet monkey Cercopithecus pygerythrus. S Afr Med J 81: 462–467PubMedGoogle Scholar