Experimental challenge of chicken vaccinated with commercially available H5 vaccines reveals loss of protection to some highly pathogenic avian influenza H5N1 strains circulating in Hong Kong/China
| Autor: | Chuk-Kwan Ho, Yi Guan, Sin Fun Sia, Shing-Chun Tang, Geraldine S. M. Luk, Y.H. Connie Leung, Kai-Chi Chow, Yu-On Wu, J. S. Malik Peiris |
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| Rok vydání: | 2013 |
| Předmět: |
Hemagglutinin Glycoproteins
Influenza Virus Biology medicine.disease_cause Poultry Antigenic drift Virus Immunity medicine Animals Amino Acid Sequence Viral shedding Poultry Diseases Immune Evasion Specific-pathogen-free Hemagglutination assay Influenza A Virus H5N1 Subtype General Veterinary General Immunology and Microbiology Vaccination Public Health Environmental and Occupational Health Hemagglutination Inhibition Tests Antigenic Variation Virology Influenza A virus subtype H5N1 Infectious Diseases Influenza Vaccines Influenza in Birds Hong Kong Molecular Medicine Chickens Sequence Alignment |
| Zdroj: | Vaccine. 31:3536-3542 |
| ISSN: | 0264-410X |
| DOI: | 10.1016/j.vaccine.2013.05.076 |
| Popis: | Highly pathogenic avian influenza (HPAI) H5N1 virus continues to circulate in poultry in Asia and Africa posing a threat to both public and animal health. Vaccination, used as an adjunct to improved bio-security and stamping-out policies, contributed to protecting poultry in Hong Kong from HPAI H5N1 infection in 2004-2008 although the virus was repeatedly detected in dead wild birds. The detection of clade 2.3.4 H5N1 viruses in poultry markets and a farm in Hong Kong in 2008 raised the question whether this virus has changed to evade protection from the H5 vaccines in use. We tested the efficacy of three commercial vaccines (Nobilis, Poulvac and Harbin Re-5 vaccine) in specific pathogen free white leghorn chickens against a challenge with A/chicken/Hong Kong/8825-2/2008 (clade 2.3.4) isolated from vaccinated poultry in Hong Kong and A/chicken/Hong Kong/782/2009 (clade 2.3.2). Harbin Re5 vaccine provided the best, albeit not complete protection against challenge with the clade 2.3.4 virus. All three vaccines provided good protection from death and significantly reduced virus shedding following challenge with the clade 2.3.2 virus. Only Harbin Re-5 was able to completely protect chickens from virus shedding as well as mortality. Sera from vaccinated chickens had lower geometric hemagglutination inhibition titers against A/chicken/Hong Kong/8825-2/08, as compared to two other clade 2.3.4 and one clade 0 virus. Alignment of amino-acid sequences of the haemagglutinin of A/chicken/Hong Kong/8825-2/08 and the other H5 viruses revealed several mutations in positions including 69, 71, 83, 95, 133,140, 162, 183, 189, 194 and 270 (H5 numbering) which may correlate with loss of vaccine protection. Our results indicated that the tested HPAI H5N1 (2.3.4) virus has undergone antigenic changes that allow it to evade immunity from poultry vaccines. This highlights the need for continued surveillance and monitoring of vaccine induced immunity, with experimental vaccine challenge studies being done where indicated. |
| Databáze: | OpenAIRE |
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