Lenexa, KS, United States
Lenexa, KS, United States

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Esaki M.,Ceva Animal Health Japan Campus | Esaki M.,Ceva Animal Health Biomune Campus | Noland L.,Ceva Animal Health Biomune Campus | Dorsey K.M.,Ceva Animal Health Biomune Campus | Yasuda A.,Ceva Animal Health Japan Campus
Journal of Poultry Science | Year: 2015

Marek’s disease virus, including turkey herpesvirus (HVT), have been utilized as vectors to express foreign antigen genes and induce immunity against the antigens in chickens. Selection of promoters in developing such vector vaccines is one of the most important factors influencing efficacy of vector vaccines. In this study, in order to find a suitable promoter for expressing the hemagglutinin gene of avian influenza virus H5 subtype in HVT vector vaccines, three HVT vector avian influenza virus H5 subtype (HVT-AI) viruses expressing the hemagglutinin gene were constructed using three promoters; the cytomegalovirus (CMV) promoter, the chicken β-actin (Bac) promoter, and CMV/Bac chimera (Pec) promoter. Of those three vector vaccines, HVT-AI with the CMV promoter induced significantly higher avian influenza virus (AIV) hemagglutinin inhibition titers than the other HVT-AI vaccines with the Bac or the Pec promoters, after inoculation into chickens at one day old. When evaluated with two of commercially available AIV enzyme-linked immunosorbent assay kits, the HVT-AI vaccines did not induce positive titers, indicating that these HVT-AI vaccines may be utilized for easy differentiation of vaccinated chickens from ones infected with field AIV. © 2015, Japan Poultry Science Association.


Esaki M.,Ceva Animal Health Biomune Campus | Esaki M.,Ceva Animal Health Japan Campus | Noland L.,Ceva Animal Health Biomune Campus | Eddins T.,Ceva Animal Health Biomune Campus | And 5 more authors.
Avian Diseases | Year: 2013

Turkey herpesvirus vector laryngotracheitis vaccine (HVT/LT) expressing the glycoprotein B gene of laryngotracheitis virus (LTV) has been developed. In vitro growth kinetics of HVT/LT were similar to those of parental turkey herpesvirus (HVT), FC-126 strain. Genetic and phenotypic stabilities of HVT/LT after in vitro (in cell culture) or in vivo (in chickens) passage were confirmed by various assays, including Southern blot analysis, western blot analysis, and an indirect immunofluorescence assay. Safety of HVT/LT was assessed by an overdose study as well as by a backpassage study in specific-pathogen-free (SPF) chickens. The overdose study indicated that HVT/LT did not cause any adverse effects in chickens. The backpassage study confirmed that HVT/LT does not revert to virulence after five passages in chickens. The vaccine did not transmit laterally from vaccinated chickens to commingled nonvaccinated chickens. Efficacy of HVT/LT was evaluated in SPF layer chickens after vaccination by the subcutaneous route at 1 day of age. The majority of the vaccinated chickens (92%-100%) were protected against challenge with virulent LTV at 7 wk of age. Efficacy of HVT/LT was further evaluated in broiler chickens from a commercial source after in ovo vaccination to embryos at 18 days of incubation. After challenge with virulent LTV at 21 and 35 days of age, 67% and 87% of HVT/LT-vaccinated chickens did not develop LT clinical signs, respectively, while 100% (21 days of age) and 73% (35 days of age) of the challenge control chickens showed clinical signs of LT. These results suggest that HVT/LT is a safe and efficacious vaccine for control of laryngotracheitis (LT). © American Association of Avian Pathologists.

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