title: Immunogenicity and protective efficacy of virus-like particles and recombinant fiber proteins in broiler-breeder vaccination against fowl adenovirus (FAdV)-8b.
abstract: Inclusion body hepatitis (IBH) is an economically important diseases in broiler chicken industry. Several serotypes of fowl adenovirus (FAdV) can cause IBH, among them, serotype FAdV-8b is associated with the majority of the IBH cases in Canada. Here, we evaluated FAdV-8b virus-like particles (VLPs) and recombinant FAdV-8b fiber proteins (expressed in E. coli) as potential broiler-breeder vaccines against IBH. For assessing the immunogenicity of vaccines, we investigated both humoral and cellular immunity. The humoral immune response was evaluated by determining total IgY and virus-neutralizing antibody in serum at 14, 28, 35 and 60days post-immunization (dpi). We examined cellular immunity using flow cytometry by determining CD4:CD8 ratio change in peripheral blood after the booster vaccination. The protective effect of vaccines was tested by challenging 14day-old progeny (n=30/group) carrying maternal antibodies (MtAb) by challenging with virulent FAdV-8b virus (1×107TCID50, FAdV-8b-SK). Although total IgY levels were comparable in all groups, the neutralizing antibody response in broiler-breeders at 35 and 60 dpi was significantly (p<0.05) higher those vaccinated with FAdV-8b VLPs followed by FAdV-8b fiber compared to fiber-knob. Moreover, vaccines comprised of FAdV-8b VLPs and FAdV-8b fiber rather than FAdV-8b fiber-knob efficiently elicited the cell-mediated immune response as evidenced by a statistically significant (p<0.05) CD8+T-cell proliferative response in broiler-breeders four days after the booster vaccination. Unlike FAdV-8b fiber-knob, FAdV-8b VLPs, and FAdV-8b fiber vaccinated broiler-breeders were able to transfer a substantial amount (28.4±9%) of MtAb to their progeny. Challenge revealed that MtAb provided 100% and 82.7% protection in progeny hatched from FAdV-8b VLPs, and FAdV-8b fiber vaccinated broiler-breeders, respectively. Collectively, our data suggest that FAdV-8b subunit vaccine-induced MtAb efficiently protected progeny against clinical IBH and broiler-breeder vaccination with subunit vaccines is a potential approach to protect against IBH.
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Ashish
authors.initials: A
authors.lastname: Gupta
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Khawaja Ashfaque
authors.initials: KA
authors.lastname: Ahmed
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Lisanework E
authors.initials: LE
authors.lastname: Ayalew
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Shelly
authors.initials: S
authors.lastname: Popowich
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Shanika
authors.initials: S
authors.lastname: Kurukulasuriya
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Kalhari
authors.initials: K
authors.lastname: Goonewardene
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Thushari
authors.initials: T
authors.lastname: Gunawardana
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Ruwani
authors.initials: R
authors.lastname: Karunarathna
authors.affiliation: Animal Health Laboratory, Laboratory Services Division, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Davor
authors.initials: D
authors.lastname: Ojkic
authors.affiliation: Vaccine and Infectious Disease Organization, 120 Veterinary Road, University of Saskatchewan, Saskatoon, SK, S7N 5E3, Canada; Vaccinology & Immunotherapeutics Program, School of Public Health, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Suresh K
authors.initials: SK
authors.lastname: Tikoo
authors.affiliation: Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Philip
authors.initials: P
authors.lastname: Willson
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada. Electronic address: susantha.gomis@usask.ca.
authors.forename: Susantha
authors.initials: S
authors.lastname: Gomis
mesh_terms: D000257:Adenoviridae Infections / Q000517:prevention & control / Q000662:veterinary*; D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D000259:Aviadenovirus / Q000235:genetics / Q000276:immunology*; D016516:CD4-CD8 Ratio; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002170:Canada; D036022:Capsid Proteins / Q000235:genetics / Q000276:immunology*; D049109:Cell Proliferation; D002645:Chickens; D007136:Immunoglobulins / Q000097:blood; D011201:Poultry Diseases / Q000517:prevention & control*; D016896:Treatment Outcome; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D058425:Vaccines, Virus-Like Particle / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D014765:Viral Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D036022:Capsid Proteins; C016512:IgY; D007136:Immunoglobulins; D014614:Vaccines, Synthetic; D058425:Vaccines, Virus-Like Particle; D014765:Viral Vaccines; C018315:hexon capsid protein, Adenovirus
keywords: FAdV-8b subunit vaccines; FAdV-8b-SK; Inclusion body hepatitis (IBH); Virus-like particles (VLPs)