title: Immunogenicity and protective efficacy of cold-adapted X-31 live attenuated pre-pandemic H5N1 influenza vaccines.
abstract: Despite global efforts to control influenza viruses, they have taken a heavy toll on human public health worldwide. Among particular threats is highly pathogenic avian H5N1 influenza virus (HPAI) due to not only its high mortality in humans but also possible human-to-human transmission either through reassortment with other human influenza viruses such as 2009 pandemic H1N1 influenza virus, or by genetic mutations. With the aim of developing effective vaccines against the H5N1 viruses, we generated two live attenuated H5N1 vaccine candidates against A/Indonesia/05/2005 (clade 2.1) and A/chicken/Korea/ES/2003 (clade 2.5) strains, in the genetic background of the cold-adapted donor strain of X-31. In mice, a single dose of immunization with each of the two vaccines was highly immunogenic inducing high titers of serum viral-neutralizing and hemagglutinin-inhibiting antibodies against the homologous H5N1 strain. Furthermore, significant levels of cross-clade antibody responses were induced by the vaccines, suggesting a broad-spectrum cross-reactivity against the heterologous H5N1 strains. The immunizations provided solid protections against heterologous lethal challenges with H5N2 virus, significantly reducing the morbidity and challenge virus replications in the respiratory tracts. The robustness of the antibody responses against both the homologous and heterologous strains, together with efficient protection against the lethal H5N2 challenge, strongly support the protection against wild type H5N1 infections. These results could serve as an experimental basis for the development of safe and effective H5N1 pre-pandemic vaccines while further addressing the biosecurity concerns associated with H5N1 HPAI.
authors.affiliation: Laboratory of Molecular Medicine, Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea.
authors.forename: Yo Han
authors.initials: YH
authors.lastname: Jang
authors.forename: Eun-Ju
authors.initials: EJ
authors.lastname: Jung
authors.forename: Young Ho
authors.initials: YH
authors.lastname: Byun
authors.forename: Kwang-Hee
authors.initials: KH
authors.lastname: Lee
authors.forename: Eun-Young
authors.initials: EY
authors.lastname: Lee
authors.forename: Yoon Jae
authors.initials: YJ
authors.lastname: Lee
authors.forename: Baik Lin
authors.initials: BL
authors.lastname: Seong
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D000917:Antibody Formation; D002645:Chickens; D003080:Cold Temperature; D056738:Cross Protection; D004285:Dogs; D004531:Eggs / Q000821:virology; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006388:Hemagglutinins; D053124:Influenza A Virus, H5N1 Subtype; D007252:Influenza Vaccines / Q000276:immunology*; D061985:Madin Darby Canine Kidney Cells; D051379:Mice; D008807:Mice, Inbred BALB C; D009500:Neutralization Tests; D009976:Orthomyxoviridae Infections / Q000276:immunology / Q000517:prevention & control*; D014613:Vaccines, Attenuated / Q000276:immunology; D014776:Virus Cultivation
chemical_list: D000914:Antibodies, Viral; D006388:Hemagglutinins; D007252:Influenza Vaccines; D014613:Vaccines, Attenuated
keywords: Cold-adaptation; Cross-reactivity; H5N1; Highly pathogenic avian influenza virus; Live attenuated influenza vaccine; X-31 ca