title: Characterization of reverse genetics-derived cold-adapted master donor virus A/Leningrad/134/17/57 (H2N2) and reassortants with H5N1 surface genes in a mouse model.
abstract: Live attenuated influenza vaccines (LAIV) offer significant advantages over subunit or split inactivated vaccines to mitigate an eventual influenza pandemic, including simpler manufacturing processes and more cross-protective immune responses. Using an established reverse genetics (rg) system for wild-type (wt) A/Leningrad/134/1957 and cold-adapted (ca) A/Leningrad/134/17/1957 (Len17) master donor virus (MDV), we produced and characterized three rg H5N1 reassortant viruses carrying modified HA and intact NA genes from either A/Vietnam/1203/2004 (H5N1, VN1203, clade 1) or A/Egypt/321/2007 (H5N1, EG321, clade 2) virus. A mouse model of infection was used to determine the infectivity and tissue tropism of the parental wt viruses compared to the ca master donor viruses as well as the H5N1 reassortants. All ca viruses showed reduced replication in lungs and enhanced replication in nasal epithelium. In addition, the H5N1 HA and NA enhanced replication in lungs unless it was restricted by the internal genes of the ca MDV. Mice inoculated twice 4 weeks apart with the H5N1 reassortant LAIV candidate viruses developed serum hemagglutination inhibition HI and IgA antibody titers to the homologous and heterologous viruses consistent with protective immunity. These animals remained healthy after challenge inoculation with a lethal dose with homologous or heterologous wt H5N1 highly pathogenic avian influenza (HPAI) viruses. The profiles of viral replication in respiratory tissues and the immunogenicity and protective efficacy characteristics of the two ca H5N1 candidate LAIV viruses warrant further development into a vaccine for human use.
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention, Department of Health and Human Services, Atlanta, Georgia, USA.
authors.forename: Irina
authors.initials: I
authors.lastname: Isakova-Sivak
authors.forename: Li-Mei
authors.initials: LM
authors.lastname: Chen
authors.forename: Melissa
authors.initials: M
authors.lastname: Bourgeois
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Matsuoka
authors.forename: J Theo M
authors.initials: JT
authors.lastname: Voeten
authors.forename: Jacco G M
authors.initials: JG
authors.lastname: Heldens
authors.forename: Han
authors.initials: H
authors.lastname: van den Bosch
authors.forename: Alexander
authors.initials: A
authors.lastname: Klimov
authors.forename: Larisa
authors.initials: L
authors.lastname: Rudenko
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Cox
authors.forename: Ruben O
authors.initials: RO
authors.lastname: Donis
mesh_terms: D000825:Animal Structures / Q000821:virology; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D004195:Disease Models, Animal; D005260:Female; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics / Q000276:immunology; D007070:Immunoglobulin A / Q000097:blood; D053121:Influenza A Virus, H2N2 Subtype / Q000235:genetics / Q000276:immunology*; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D008807:Mice, Inbred BALB C; D009439:Neuraminidase / Q000235:genetics / Q000276:immunology; D009976:Orthomyxoviridae Infections / Q000517:prevention & control; D016865:Reassortant Viruses / Q000235:genetics / Q000276:immunology*; D059386:Reverse Genetics; D016019:Survival Analysis; D014611:Vaccination / Q000379:methods; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014764:Viral Proteins / Q000235:genetics / Q000276:immunology; D014774:Virulence
chemical_list: D000914:Antibodies, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007070:Immunoglobulin A; D007252:Influenza Vaccines; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic; D014764:Viral Proteins; C487630:NA protein, influenza A virus; D009439:Neuraminidase