title: Evaluation of the Protection Efficacy of a Serotype 1 Marek's Disease Virus-Vectored Bivalent Vaccine Against Infectious Laryngotracheitis and Marek's Disease.
abstract: Laryngotracheitis (LT) is a highly contagious respiratory disease of chickens that produces significant economic losses to the poultry industry. Traditionally, LT has been controlled by administration of modified live vaccines. In recent years, the use of recombinant DNA-derived vaccines using turkey herpesvirus (HVT) and fowlpox virus has expanded, as they protect not only against the vector used but also against LT. However, HVT-based vaccines confer limited protection against challenge, with emergent very virulent plus Marek's disease virus (vv+MDV). Serotype 1 vaccines have been proven to be the most efficient against vv+MDV. In particular, deletion of oncogene MEQ from the oncogenic vvMDV strain Md5 (BACδMEQ) resulted in a very efficient vaccine against vv+MDV. In this work, we have developed two recombinant vaccines against MD and LT by using BACδMEQ as a vector that carries either the LT virus (LTV) gene glycoprotein B (gB; BACΔMEQ-gB) or LTV gene glycoprotein J (gJ; BACδMEQ-gJ). We have evaluated the protection that these recombinant vaccines confer against MD and LT challenge when administered alone or in combination. Our results demonstrated that both bivalent vaccines (BACΔMEQ-gB and BACδMEQ-gJ) replicated in chickens and were safe to use in commercial meat-type chickens bearing maternal antibodies against MDV. BACΔMEQ-gB protected as well as a commercial recombinant (r)HVT-LT vaccine against challenge with LTV. However, BACδMEQ-gJ did not protect adequately against LT challenge or increase protection conferred by BACΔMEQ-gB when administered in combination. On the other hand, both BACΔMEQ-gB and BACδMEQ-gJ, administered alone or in combination, protected better against an early challenge with vv+MDV strain 648A than commercial strains of rHVT-LT or CVI988. Our results open a new avenue in the development of recombinant vaccines by using serotype 1 MDV as vectors.
authors.affiliation: A Department of Population Health and Pathobiology, Veterinary School, North Carolina State University, 1060 William Moore Drive, Raleigh, NC 27607.
authors.forename: Isabel M
authors.initials: IM
authors.lastname: Gimeno
authors.affiliation: A Department of Population Health and Pathobiology, Veterinary School, North Carolina State University, 1060 William Moore Drive, Raleigh, NC 27607.
authors.forename: Aneg L
authors.initials: AL
authors.lastname: Cortes
authors.affiliation: A Department of Population Health and Pathobiology, Veterinary School, North Carolina State University, 1060 William Moore Drive, Raleigh, NC 27607.
authors.forename: Nik M
authors.initials: NM
authors.lastname: Faiz
authors.affiliation: A Department of Population Health and Pathobiology, Veterinary School, North Carolina State University, 1060 William Moore Drive, Raleigh, NC 27607.
authors.forename: Byron A
authors.initials: BA
authors.lastname: Hernandez-Ortiz
authors.affiliation: A Department of Population Health and Pathobiology, Veterinary School, North Carolina State University, 1060 William Moore Drive, Raleigh, NC 27607.
authors.forename: James S
authors.initials: JS
authors.lastname: Guy
authors.affiliation: B U.S. Department of Agriculture, Agricultural Research Service, Avian Disease and Oncology Laboratory, 4279 East Mount Hope Road, East Lansing, MI 48823.
authors.forename: Henry D
authors.initials: HD
authors.lastname: Hunt
authors.affiliation: B U.S. Department of Agriculture, Agricultural Research Service, Avian Disease and Oncology Laboratory, 4279 East Mount Hope Road, East Lansing, MI 48823.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Silva
mesh_terms: D000818:Animals; D002645:Chickens; D005260:Female; D006566:Herpesviridae Infections / Q000517:prevention & control / Q000662:veterinary*; D001352:Herpesvirus 1, Gallid / Q000276:immunology*; D025922:Mardivirus / Q000145:classification* / Q000276:immunology; D008380:Marek Disease / Q000517:prevention & control*; D010865:Pilot Projects; D019444:Vaccines, DNA; D014765:Viral Vaccines / Q000276:immunology*; D014779:Virus Replication
chemical_list: D019444:Vaccines, DNA; D014765:Viral Vaccines
keywords: Marek's disease; avian; control; herpesvirus; laryngotracheitis; poultry; vaccine