Evaluation of a pseudotyped virus neutralisation test for the measurement of equine influenza virus-neutralising antibody responses induced by vaccination and infection

Rebecca Kinsley (1) , Stéphane Pronost (2, 3) , Manuelle de Bock (4) , Nigel Temperton (1) , Janet Daly (5) , Romain Paillot (2, 3, 6) , Simon Scott (1)

1 Viral Pseudotype Unit
2 LABÉO - LABÉO, Pôle d’analyses et de recherche de Normandie
3 BIOTARGEN - Biologie, génétique et thérapies ostéoarticulaires et respiratoires
4 Elanco Animal Health (Belgium)
5 UON - University of Nottingham, UK
6 AHT - Animal Health Trust

Equine influenza is a major respiratory disease of horses that is largely controlled by vaccination in some equine populations. Virus-neutralising antibodies, the mainstay of the protective immune response, are problematic in assaying for equine influenza virus, as most strains do not replicate efficiently in cell culture. Surrogate measures of protective antibody responses include the haemagglutination inhibition (HI) test and single radial haemolysis (SRH) assay. For this study, a pseudotyped virus, bearing an envelope containing the haemagglutinin (HA) from the Florida clade 2 equine influenza virus strain A/equine/Richmond/1/07 (H3N8), was generated to measure HA-specific neutralising antibodies in serum samples (n = 134) from vaccinated or experimentally-infected ponies using a pseudotyped virus neutralization test (PVNT). Overall, the results of PVNT were in good agreement with results from the SRH assay (100% sensitivity, 68.53% specificity) and HI test (99.2% sensitivity, 49.03% specificity). The PVNT was apparently more sensitive than either the SRH assay or the HI test, which could be advantageous for studying the antibody kinetics, particularly when antibody levels are low. Nevertheless, further studies are required to determine whether a protective antibody level can be defined for the SRH assay and to ascertain the inter-laboratory reproducibility. In conclusion, the PVNT efficiently measures neutralising antibodies after immunization and/or experimental infection in the natural host, and may complement existing antibody assays.

Mots clés: equine influenza; horse; pseudotype virus; vaccine

Domaines: Médecine vétérinaire et santé animale

Rebecca Kinsley, Stéphane Pronost, Manuelle de Bock, Nigel Temperton, Janet Daly, et al.. Evaluation of a pseudotyped virus neutralisation test for the measurement of equine influenza virus-neutralising antibody responses induced by vaccination and infection. Vaccines, 2020, 8 (3), pp.466. ⟨10.3390/vaccines8030466⟩. ⟨hal-02931047⟩