Protective efficacy of a recombinant herpesvirus of turkeys as an in ovo vaccine against Newcastle and Marek's diseases in specific-pathogen-free chickens

• Published in: Vaccine Vol. 14; no. 6; pp. 469 - 477
• Main Authors: Reddy, S.K., Sharma, J.M., Ahmad, J., Reddy, D.N., McMillen, J.K., Cook, S.M., Wild, M.A., Schwartz, R.D.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-04-1996; Elsevier
• Subjects: Animals; Biological and medical sciences; Chick Embryo; Chickens; Fundamental and applied biological sciences. Psychology; fusion and hemagglutinin genes; glycoprotein A,B of Marek's disease virus; herpesvirus; Herpesvirus 2, Gallid - genetics; Herpesvirus 2, Gallid - immunology; in ovo vaccination; Marek Disease - prevention & control; Marek's disease; Microbiology; Newcastle disease; Newcastle Disease - immunology; Newcastle Disease - prevention & control; Newcastle disease virus - immunology; Recombinant herpesvirus of turkeys; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies; Vaccines, Synthetic - adverse effects; Vaccines, Synthetic - immunology; Viral Vaccines - adverse effects; Viral Vaccines - genetics; Viral Vaccines - immunology; Virology; in ovo vaccination; Newcastle disease; Marek's disease; fusion and hemagglutinin genes; glycoprotein A,B of Marek's disease virus; Recombinant herpesvirus of turkeys; Gammaherpesvirinae; Immunoprotection; Immunization; Immune response; Egg; Antibody; Toxicity; Recombinant virus; Herpesviridae; Marek disease; Vaccine; Infection; Virus; Vertebrata; Turkey herpesvirus; Immunogenicity; Efficiency; Viral disease; Animal; Chicken; Aves; Veterinary; Humoral immunity
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/0264-410X(95)00242-S

We investigated the potential of a herpesvirus of turkey (HVT)-based recombinant virus (rHVT) as an in
in ovo vaccine to protect specific-pathogen-free chickens against Newcastle disease (ND) and Marek's disease (MD). The rHVT, designed to express fusion (F) and hemagglutinin-neuraminidase (HN) glycoproteins of the lentogenic Hitchner B1 strain of ND virus (NDV), as well as glycoproteins A and B of the GA strain of serotype 1 MD virus (MDV) was efficacious in protecting chickens against ND and MD. No adverse effects on hatchability or the survival of chickens were observed following
in ovo vaccination with rHVT. A single administration at embryonation day 18 (ED18) or at hatch protected chickens against challenge-exposures with virulent MDV strain RB-1B and velogenic NDV strain GB-Texas (NDV-GB-TX). Vaccinated chickens developed antibodies against both viruses as detected by serological tests, namely, hemagglutination inhibition, virus neutralization and western immunoblotting for NDV, and immunofluorescence and radioimmunoprecipitation assays for MDV. PCR analysis showed that
in ovo vaccination with rHVT resulted in a persistent infection leading to systemic immunity against ND for up to 8 weeks of age, the longest period of time tested in this study. However, virus isolation tests indicated that rHVT-vaccinated chickens were only partially protected from the replication of NDV-GB-TX in the trachea. The results of the study indicate that rHVT is safe for both ED18 and posthatch vaccination for ND and MD, and because the vaccine persists, it may induce longer lasting immunity than conventional live NDV vaccines.