title: Vaccine protection of chickens against antigenically diverse H5 highly pathogenic avian influenza isolates with a live HVT vector vaccine expressing the influenza hemagglutinin gene derived from a clade 2.2 avian influenza virus.
abstract: Vaccination is an important tool in the protection of poultry against avian influenza (AI). For field use, the overwhelming majority of AI vaccines produced are inactivated whole virus formulated into an oil emulsion. However, recombinant vectored vaccines are gaining use for their ability to induce protection against heterologous isolates and ability to overcome maternal antibody interference. In these studies, we compared protection of chickens provided by a turkey herpesvirus (HVT) vector vaccine expressing the hemagglutinin (HA) gene from a clade 2.2 H5N1 strain (A/swan/Hungary/4999/2006) against homologous H5N1 as well as heterologous H5N1 and H5N2 highly pathogenic (HP) AI challenge. The results demonstrated all vaccinated birds were protected from clinical signs of disease and mortality following homologous challenge. In addition, oral and cloacal swabs taken from challenged birds demonstrated that vaccinated birds had lower incidence and titers of viral shedding compared to sham-vaccinated birds. Following heterologous H5N1 or H5N2 HPAI challenge, 80-95% of birds receiving the HVT vector AI vaccine at day of age survived challenge with fewer birds shedding virus after challenge than sham vaccinated birds. In vitro cytotoxicity analysis demonstrated that splenic T lymphocytes from HVT-vector-AI vaccinated chickens recognized MHC-matched target cells infected with H5, as well as H6, H7, or H9 AI virus. Taken together, these studies provide support for the use of HVT vector vaccines expressing HA to protect poultry against multiple lineages of HPAI, and that both humoral and cellular immunity induced by live vaccines likely contributes to protection.
authors.affiliation: Exotic and Emerging Avian Disease Research Unit, Southeast Poultry Research Laboratory, Agricultural Research Service, USDA, 934 College Station Road, Athens, GA 30605, United States. Electronic address: darrell.kapczynski@ars.usda.gov.
authors.forename: Darrell R
authors.initials: DR
authors.lastname: Kapczynski
authors.affiliation: Ceva Animal Health, Lenexa, KS, United States.
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Esaki
authors.affiliation: Ceva Animal Health, Lenexa, KS, United States.
authors.forename: Kristi M
authors.initials: KM
authors.lastname: Dorsey
authors.affiliation: Exotic and Emerging Avian Disease Research Unit, Southeast Poultry Research Laboratory, Agricultural Research Service, USDA, 934 College Station Road, Athens, GA 30605, United States.
authors.forename: Haijun
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Department of Population Health, College of Veterinary Medicine, The University of Georgia, Athens, GA, United States.
authors.forename: Mark
authors.initials: M
authors.lastname: Jackwood
authors.affiliation: Ceva Animal Health, Lenexa, KS, United States.
authors.forename: Mauro
authors.initials: M
authors.lastname: Moraes
authors.affiliation: Ceva Animal Health, Libourne, France.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Gardin
mesh_terms: D000818:Animals; D002645:Chickens; D003601:Cytotoxicity Tests, Immunologic; D004337:Drug Carriers; D005822:Genetic Vectors; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics / Q000276:immunology*; D026002:Herpesvirus 1, Meleagrid / Q000235:genetics; D064789:Immunity, Heterologous; D053124:Influenza A Virus, H5N1 Subtype / Q000276:immunology; D053125:Influenza A Virus, H5N2 Subtype / Q000276:immunology; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D005585:Influenza in Birds / Q000276:immunology / Q000473:pathology / Q000517:prevention & control* / Q000821:virology; D016019:Survival Analysis; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology; D017201:Virus Shedding
chemical_list: D004337:Drug Carriers; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic; C109963:hemagglutinin, avian influenza A virus
keywords: Antibodies; Cellular immunity; Highly pathogenic avian influenza; Poultry; Turkey herpesvirus; Vector-based vaccine