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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.


PubMed | Ceva Animal Health Japan Campus
Type: Journal Article | Journal: The Journal of veterinary medical science | Year: 2016

The bacterial artificial chromosome (BAC) technology has been a mainstay approach for generating recombinant viruses, and several methods for excision of the mini-F sequences from the viral BAC vectors have been developed. However, these strategies either require complicated procedures or leave scars of inserted sequences. To overcome these problems, a new method to excise the mini-F sequences from viral BAC vectors based on the Removal of Inserted BAC after linearizatiON (RIBON) strategy was developed in this study for herpesvirus of turkeys (HVT). Enhanced green fluorescent protein (eGFP) DNA and the mini-F sequences were inserted into the gene encoding HVT thymidine kinase (TK) by homologous recombination in chicken embryo fibroblasts (CEFs), and the constructed HVT-BAC vector was used to transform Escherichia coli (pHVT-BAC). To remove the inserted eGFP and mini-F sequences, pHVT-BAC was linearized using a homing endonuclease I-SceI and used to cotransfect CEFs together with a plasmid containing the TK gene of HVT. The obtained viruses (44%) did not express eGFP, and DNA sequencing of isolated clones revealed that they were completely free of the inserted BAC sequences. Moreover, growth kinetics and plaque morphology of reconstituted viruses were comparable with those of the parental HVT. The results of this study demonstrate that the novel RIBON approach to remove mini-F sequences from the viral genome is simple and effective.


PubMed | Ceva Animal Health Japan Campus
Type: Journal Article | Journal: Avian diseases | Year: 2016

Herpesvirus of turkeys (HVT) is a widely used vector for poultry vaccines. However, different HVTs expressing different foreign antigens cannot always be used simultaneously because of the risk of recombination and interference. In this study, we inoculated a mixture of an HVT-expressing the antigen of Newcastle disease virus (NDV; HVT/ND) and Mareks disease virus (MDV) serotype 1 Rispens virus expressing the antigen of infectious bursal disease virus (IBD; Ripens/IBD) into chickens. This mixture showed 94%, 100%, or 94% protection against MDV, IBDV, or NDV challenge, respectively. In conclusion, the combination of Rispens/IBD and HVT/ND is effective for vaccination against MDV, IBDV, and NDV without significant interference.


Ishihara Y.,Ceva Animal Health Japan Campus | Esaki M.,Ceva Animal Health Japan Campus | Saitoh S.,Ceva Animal Health Japan Campus | Yasuda A.,Ceva Animal Health Japan Campus
Avian Diseases | Year: 2016

Herpesvirus of turkeys (HVT) is a widely used vector for poultry vaccines. However, different HVTs expressing different foreign antigens cannot always be used simultaneously because of the risk of recombination and interference. In this study, we inoculated a mixture of an HVT-expressing the antigen of Newcastle disease virus (NDV; HVT/ND) and Marek's disease virus (MDV) serotype 1 Rispens virus expressing the antigen of infectious bursal disease virus (IBD; Ripens/IBD) into chickens. This mixture showed 94%, 100%, or 94% protection against MDV, IBDV, or NDV challenge, respectively. In conclusion, the combination of Rispens/IBD and HVT/ND is effective for vaccination against MDV, IBDV, and NDV without significant interference.


Ishihara Y.,Ceva Animal Health Japan Campus | Esaki M.,Ceva Animal Health Japan Campus | Saitoh S.,Ceva Animal Health Japan Campus | Sato T.,Ceva Animal Health Japan Campus | Yasuda A.,Ceva Animal Health Japan Campus
Avian Diseases | Year: 2016

Infectious bursal disease (IBD) is a major disease affecting the poultry industry and is caused by infection with IBD virus (IBDV). To develop a novel vaccine to prevent IBD in chickens, recombinant Marek's disease virus Rispens viruses carrying the VP2 gene of IBDV driven by five different promoters (Rispens/IBD) were constructed using homologous recombination and a bacterial artificial chromosome (BAC). Rispens/IBD driven by the chicken beta-actin (Bac) promoter (Rispens/Bac-IBD), Rous sarcoma virus promoter, or simian virus 40 promoter were administered to 1-day-old SPF chicks, and the protective efficacy against IBDV was evaluated by challenging chicks with virulent IBDV. As a result, Rispens/Bac-IBD showed the best protection (87%). Next, we constructed the virus driven by the Bac-derived Coa5 promoter (Rispens/Coa5-IBD) for a secondary in vivo trial using commercial layer chickens since Rispens/Bac-IBD was thought to be genetically unstable. Rispens/Coa5-IBD showed stability in vitro and exhibited better antibody production and protection during challenge against virulent IBDV at both 5 (95%) and 7 wk of age (91%) compared with that of Rispens/Bac-IBD (90% at 5 wk of age and 84% at 7 wk of age). Thus, Rispens/Coa5-IBD may be a novel promising vaccine against IBD and virulent Marek's disease. © 2016 American Association of Avian Pathologists.

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