Protective immunization of horses with a recombinant canarypox virus vectored vaccine co-expressing genes encoding the outer capsid proteins of African horse sickness virus

Alan J. Guthrie, Melvyn Quan, Carina W. Lourens, Jean Christophe Audonnet, Jules M. Minke, Jiansheng Yao, Ling He, Robert Nordgren, Ian Gardner, Nigel J Maclachlan

Research output: Contribution to journalArticle

49 Scopus citations

Abstract

We describe the development and preliminary characterization of a recombinant canarypox virus vectored (ALVAC®) vaccine for protective immunization of equids against African horse sickness virus (AHSV) infection. Horses (n = 8) immunized with either of two concentrations of recombinant canarypox virus vector (ALVAC-AHSV) co-expressing synthetic genes encoding the outer capsid proteins (VP2 and VP5) of AHSV serotype 4 (AHSV-4) developed variable titres (<10-80) of virus-specific neutralizing antibodies and were completely resistant to challenge infection with a virulent strain of AHSV-4. In contrast, a horse immunized with a commercial recombinant canarypox virus vectored vaccine expressing the haemagglutinin genes of two equine influenza H3N8 viruses was seronegative to AHSV and following infection with virulent AHSV-4 developed pyrexia, thrombocytopenia and marked oedema of the supraorbital fossae typical of the "dikkop" or cardiac form of African horse sickness. AHSV was detected by virus isolation and quantitative reverse transcriptase polymerase chain reaction in the blood of the control horse from 8 days onwards after challenge infection whereas AHSV was not detected at any time in the blood of the ALVAC-AHSV vaccinated horses. The control horse seroconverted to AHSV by 2 weeks after challenge infection as determined by both virus neutralization and ELISA assays, whereas six of eight of the ALVAC-AHSV vaccinated horses did not seroconvert by either assay following challenge infection with virulent AHSV-4. These data confirm that the ALVAC-AHSV vaccine will be useful for the protective immunization of equids against African horse sickness, and avoids many of the problems inherent to live-attenuated AHSV vaccines.

Original languageEnglish (US)
Pages (from-to)4434-4438
Number of pages5
JournalVaccine
Volume27
Issue number33
DOIs
StatePublished - Jul 16 2009

Keywords

  • African horse sickness
  • Canarypox virus
  • Horses
  • Vaccine

ASJC Scopus subject areas

  • Immunology and Microbiology(all)
  • Infectious Diseases
  • Public Health, Environmental and Occupational Health
  • veterinary(all)
  • Molecular Medicine

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