Protection and Antibody Response Caused by Turkey Herpesvirus Vector Newcastle Disease Vaccine

Abstract

Newcastle disease (ND) is prevalent worldwide and causes significant clinical and economic losses to the poultry industry. Current vaccine programs using live attenuated vaccines and inactivated vaccines have limitations, and new vaccines with distinct features are needed. To offer an alternative solution to control ND, a turkey herpesvirus vector Newcastle disease vaccine (HVT/ND) expressing the fusion gene of Newcastle disease virus (NDV) has been developed. First, immunogenicity of the HVT/ND was evaluated in specific-pathogen-free layer chickens after vaccination by the in ovo route to 18-day-old embryos or by the subcutaneous route to 1-day-old chicks. Antibodies against NDV were detected at 24 days of age using a commercial NDV enzyme-linked immunosorbent assay (ELISA) kit and the hemagglutination inhibition test. At least 90% of chickens were protected against challenge with velogenic neurotropic NDV Texas GB strain (genotype II; pathotype velogenic) at 4 wk of age, while none of the nonvaccinated, challenged controls were protected from challenge. Second, the age at which a vaccinated chicken elicits an immunologic response to the HVT/ND prepared for this study, and thus is protected from ND virus, was assessed in commercial broiler chickens after in ovo vaccination of 18-day-old embryos. Challenge was conducted using a low-virulence NDV strain (genotype II; pathotype lentogenic) via the respiratory tract each week between 1 and 5 wk of age, in order to mimic the situation in areas where virulent NDV strains do not normally exist and low-virulence strains cause mild respiratory symptoms leading to economic losses. Protection was evaluated by the presence or absence of isolated virus from tracheal swabs at 5 days postchallenge. Partial protection was observed at 3 wk of age, when 6 out of 10 (60%) chickens were protected. Full protection was obtained at 4 and 5 wk of age, when 9 out of 10 (90%) and 10 out of 10 (100%) chickens were protected, respectively. Finally, protection against challenge with virulent Texas GB strain at 19 wk of age was evaluated in commercial female layer chickens vaccinated at 1 day of age with HVT/ND. All of the vaccinated chickens were protected, while all of the challenge controls succumbed to the challenge. Furthermore, anti-NDV antibodies measured by ELISA were maintained through 50 wk of age.

Newcastle disease vaccines—A solved problem or a continuous challenge?

“…The antibodies induced after the administration of the rHVT-ND vaccines occur at the same time in which maternal antibodies are waning. The rHVT-ND vaccines have many benefits, among these is that they can be administered in ovo at the hatchery or subcutaneously after hatch, and produce long-term immunity (Armour and García, 2014;Esaki et al, 2013). However, the rHVT-ND vaccines are cell associated, so like Marek's disease vaccines, they are required to be kept in liquid nitrogen, and to be administered within an hour of being thawed.…”

Viral vaccines and their manufacturing cell substrates: New trends and designs in modern vaccinology

“…Ideally, vectored vaccines for human use are replication-defective viruses able to deliver the antigen(s) to the target cell in the form of genetic material. Nevertheless, replication competent vectored vaccines have been developed for veterinary use [67]. A myriad of viral vectors are available based on adenovirus, poxvirus, herpes simplex virus, cytomegalovirus, alphaviruses, or adeno-associated virus.…”

Quantification of rHVT-F genome load in feather follicles by specific real-time qPCR as an indicator of NDV-specific humoral immunity induced by day-old vaccination in SPF chickens

“…According to its useful characteristics previously reviewed (Schat & Nair, 2008), the HVT, mainly the FC126 strain, has been widely and successfully used as vector for recombinant bivalent vaccine (rHVT) to protect chickens against ND (Reddy et al, 1996;Rauw et al, 2010;Palya et al, 2012Palya et al, , 2014Esaki et al, 2013), infectious bursal disease virus (Darteil et al, 1995;Tsukamoto et al, 2002;Bublot et al, 2007;Le Gros et al, 2009;Perozo et al, 2009), avian influenza (Gao et al, 2011;Rauw et al, 2012;Soejoedono et al, 2012) and infectious laryngotracheitis (Johnson et al, 2010;Gimeno et al, 2011a). This success is related to (i) its safety, (ii) the possibility of an early administration, which could be in ovo or at day-old without adverse effects on hatchability or survival of vaccinated chicks, (iii) its low sensitivity to interference with maternally derived antibody (MDA) when injected in the cell-associated form and (iv) its potential for long-term induction of protective immunity against pathogens.…”