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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Avian Disease and Oncology Research » Research » Publications at this Location » Publication #311808
Title: Biological characterization of a serotype 1 Marek’s disease virus-vectored Bi-valent 4 vaccine for infectious laryngotracheitis and Marek’s disease

Author
item GIMENO, ISABEL - North Carolina State University
item CORTES, ANEG - North Carolina State University
item FAIZ, NIK - North Carolina State University
item HERNANDEZ-ORTIZ, BYRON - North Carolina State University
item GUY, JAMES - North Carolina State University
item Hunt, Henry
item Silva, Robert

Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2015
Publication Date: N/A
Citation: N/A

Interpretive Summary: A recombinant vaccine to reduce Laryngotracheitis was developed using the Marek’s disease virus as the primary vaccine. The Marek’s disease virus was attenuated by removing it’s oncogene and inserting regions of the Laryngotracheitis virus to induce an immune response and protect against Laryngotracheitis. This recombinant vaccine can be injected in-ova and protect chickens against both Marek’s disease and Laryngotracheitis.

Technical 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 (FPV) have 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 very virulent MDV strain Md5 (BAC'MEQ) resulted in a very efficient vaccine against vv+MDV. In this work, we have developed two recombinant vaccines MD-LT using BAC'MEQ as a vector that carries either LT virus (LTV) gene gB (BAC'MEQ-gB) or LTV gene gJ (BAC'MEQ-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 (BAC'MEQ-gB, and BAC'MEQ-gJ) replicated in chickens and were safe to use in commercial meat type chickens bearing maternal antibodies against MDV. BAC'MEQ-gB protected as well as a commercial rHVT-LT vaccine against challenge with LTV. However, BAC'MEQ-gJ did not protect adequately against LT challenge nor increase protection conferred by BAC'MEQ-gB when administered in combination. On the other hand, both BAC'MEQ-gB and BAC'MEQ-gJ, administered alone or in combination, protected better against an early challenge with vv+MDV strain 648A than 4 commercial strains of rHVT-LT or CVI988. Our results open a new avenue in the development of recombinant vaccines using serotype 1 MDV as vectors.