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

• Published in: Clinical and vaccine immunology Vol. 21; no. 5; pp. 722 - 731
• Main Authors: Isakova-Sivak, Irina, Chen, Li-Mei, Bourgeois, Melissa, Matsuoka, Yumiko, Voeten, J Theo M, Heldens, Jacco G M, van den Bosch, Han, Klimov, Alexander, Rudenko, Larisa, Cox, Nancy J, Donis, Ruben O
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 01.05.2014
• Subjects: Animal Structures - virology; Animals; Antibodies, Viral - blood; Disease Models, Animal; Female; Hemagglutinin Glycoproteins, Influenza Virus - genetics; Hemagglutinin Glycoproteins, Influenza Virus - immunology; Immunoglobulin A - blood; Influenza A Virus, H2N2 Subtype - genetics; Influenza A Virus, H2N2 Subtype - immunology; Influenza A Virus, H5N1 Subtype - genetics; Influenza A Virus, H5N1 Subtype - immunology; Influenza Vaccines - administration & dosage; Influenza Vaccines - genetics; Influenza Vaccines - immunology; Mice, Inbred BALB C; Neuraminidase - genetics; Neuraminidase - immunology; Orthomyxoviridae Infections - prevention & control; Reassortant Viruses - genetics; Reassortant Viruses - immunology; Reverse Genetics; Survival Analysis; Vaccination - methods; Vaccines; Vaccines, Attenuated - administration & dosage; Vaccines, Attenuated - genetics; Vaccines, Attenuated - immunology; Vaccines, Synthetic - administration & dosage; Vaccines, Synthetic - genetics; Vaccines, Synthetic - immunology; Viral Proteins - genetics; Viral Proteins - immunology; Virulence
• ISSN: 1556-6811; 1556-679X; 1556-679X
• DOI: 10.1128/CVI.00819-13

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.