title: Evaluation of the Protective Efficacy of Poly I:C as an Adjuvant for H9N2 Subtype Avian Influenza Inactivated Vaccine and Its Mechanism of Action in Ducks.
abstract: Current commercial H9 avian influenza vaccines cannot provide satisfactory protective immunity against antigenic variant influenza viruses in ducks. Poly I:C, when used as an adjuvant, improves humoral and cellular immunity in many animals but has not been tested in ducks. In this study, we investigated the protective efficacy of Poly I:C as an adjuvant for an inactivated H9N2 Avian influenza vaccine in ducks. We found that an H9N2 vaccine administered with poly I:C (H9-PIC vaccine) induced a significantly more rapid response with higher anti-influenza antibody titers than those of the vaccine alone (H9 vaccine). Moreover, virus shedding was reduced in ducks immunized with the H9-PIC vaccine after challenge with an H9 subtype antigenic variant viruses. IFN-α, IFN-γ, IL-6 and MHC-II mRNA levels were all elevated in ducks receiving the H9-PIC vaccine. In addition, lower expression level of MHC-I may be a reason for inefficient protective ability against heterologous influenza viruses in H9-PIC vaccination of ducks. In conclusion, poly I:C adjuvant enhanced both humoral and cellular immune responses in ducks induced by immunization of inactivated H9N2 vaccine.
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Tianhe District, Guangzhou, Guangdong Province, China.
authors.forename: Aiguo
authors.initials: A
authors.lastname: Zhang
authors.affiliation: Guangdong Enterprise Key Laboratory of Biotechnology R&D of Veterinary Biologics, Guangdong, Zhaoqing, Guangdong Province, China.
authors.forename: Hanzhang
authors.initials: H
authors.lastname: Lai
authors.affiliation: Guangdong Enterprise Key Laboratory of Biotechnology R&D of Veterinary Biologics, Guangdong, Zhaoqing, Guangdong Province, China.
authors.forename: Jiahua
authors.initials: J
authors.lastname: Xu
authors.affiliation: Guangdong Enterprise Key Laboratory of Biotechnology R&D of Veterinary Biologics, Guangdong, Zhaoqing, Guangdong Province, China.
authors.forename: Wenke
authors.initials: W
authors.lastname: Huang
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Tianhe District, Guangzhou, Guangdong Province, China.
authors.forename: Yufu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Tianhe District, Guangzhou, Guangdong Province, China.
authors.forename: Dawei
authors.initials: D
authors.lastname: Zhao
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Tianhe District, Guangzhou, Guangdong Province, China.
authors.forename: Ruiai
authors.initials: R
authors.lastname: Chen
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D000917:Antibody Formation / Q000276:immunology; D004372:Ducks / Q000235:genetics / Q000276:immunology* / Q000821:virology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006385:Hemagglutination Inhibition Tests; D053127:Influenza A Virus, H9N2 Subtype / Q000187:drug effects / Q000276:immunology*; D007252:Influenza Vaccines / Q000276:immunology*; D005585:Influenza in Birds / Q000097:blood / Q000276:immunology / Q000821:virology*; D011070:Poly I-C / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D013154:Spleen / Q000187:drug effects / Q000378:metabolism; D014611:Vaccination; D015164:Vaccines, Inactivated / Q000276:immunology*; D017201:Virus Shedding / Q000187:drug effects
chemical_list: D000276:Adjuvants, Immunologic; D007252:Influenza Vaccines; D012333:RNA, Messenger; D015164:Vaccines, Inactivated; D011070:Poly I-C