ABSTRACT
Reassortants with surface antigens from potentially pandemic A/H2N2 and A/H7N9 influenza viruses were created on the basis of attenuated and highly reproductive A/Hong Kong/1/68/162/35(H3N2) donor virus obtained in the Research institute of influenza. High reproductive activity of reassortant viruses and immunogenicity of live and inactivated influenza vaccines based on these viruses indicate the possibility to use obtained reassortants for production of live and inactivated vaccines against potentially pandemic influenza A viruses.
ABSTRACT
Cold-adapted influenza virus A/HK/1/68/162/35(H3N2) was developed as unified donor of attenuation and high reproductive capacity forvaccine strains. The reassortant of this donor with surface antigens of highly pathogenic strain Alchicken/Astana/6/05 (H5N1) was tested in guinea pigs as a live or inactivated preparation. Immunization with both formulations induced equal levels of serum virus specific antibodies, while the level of mucosal antibodies was significantly higher in animals immunized with live virus. The challenge with the homologous virus demonstrated complete virus clearance only in this group, thereby indicating a direct correlation of the protection level with the level of mucosal antibodies.
Subject(s)
Antibodies, Viral/immunology , Influenza A Virus, H2N2 Subtype/immunology , Influenza A Virus, H5N1 Subtype/immunology , Influenza Vaccines/immunology , Neuraminidase/immunology , Orthomyxoviridae Infections/prevention & control , Reassortant Viruses/immunology , Adaptation, Biological , Animals , Antibodies, Viral/blood , Cold Temperature , Guinea Pigs , Immunity, Mucosal , Immunization , Influenza A Virus, H2N2 Subtype/genetics , Influenza A Virus, H5N1 Subtype/genetics , Influenza Vaccines/administration & dosage , Neuraminidase/genetics , Neutralization Tests , Orthomyxoviridae Infections/immunology , Orthomyxoviridae Infections/virology , Reassortant Viruses/genetics , Respiratory Mucosa/immunology , Respiratory Mucosa/virology , Vaccines, AttenuatedABSTRACT
Live and inactivated vaccines are currently produced using virus reassortants originating from various gene donors of internal proteins. Based on the pandemic virus A/Hong Kong/1/68 (H3N2), a cold-adapted thermo-sensitive strain A/Hong Kong/1/68/162/35 was generated. It is distinguished for its high reproductive capacity (9-9.5 lg EID50), and hemagglutinating activity (1:1024-1:2048). The strain has ts and ca phenotype: reproductive capacity at t = 39 degrees C is 1.0 lg EID50; at t = 26 degrees C, 8.5 lg EID50. A total of 16 mutations have emerged from comprehensive sequencing of the virus genome. Among them 10 mutations were located in the genes of polymerase complex and NP, with respective amino-acid substitutions. The stability of strain characteristics, such as attenuation to humans and high reproductive capacity, were confirmed by repeated sequencing of the genome after tenfold passing of the virus in chicken embryos. Reassortants of the strain A/Hong Kong/1/68/162/35 with the wild-type viruses have inherited useful features of donor virus.
Subject(s)
Influenza A Virus, H3N2 Subtype , Influenza Vaccines/genetics , Influenza, Human , Vaccines, Attenuated , Cold Temperature , Humans , Influenza A Virus, H3N2 Subtype/genetics , Influenza A Virus, H3N2 Subtype/immunology , Influenza, Human/genetics , Influenza, Human/prevention & control , Influenza, Human/virology , Mutation , Reassortant Viruses/genetics , Temperature , Viral Proteins/geneticsABSTRACT
Influenza reassortant viruses A/SPb/HK/09(H1N1), A/Astana/HK/2009 (H5N1), A/Otar/HK/2010(H3N8), and A/Perth/ HK/2011(H3N2), carrying surface antigens of different subtypes, were constructed on the basis of new potential unified donor strain A/HK/1/68/162/35(H3N2). The virulence and reproduction activity of the obtained reassortants were tested. The safety of the candidate live and inactivated influenza vaccines produced from the reassortant viruses was demonstrated. The study demonstrates that A/HK/1/68/162/35 can be used as a unified donor for attenuated and high-yield vaccine reassortants.
Subject(s)
Influenza Vaccines , Influenza, Human , Vaccines, Attenuated , Vaccines, Inactivated , Animals , Humans , Influenza A Virus, H1N1 Subtype/genetics , Influenza A Virus, H1N1 Subtype/immunology , Influenza A Virus, H1N1 Subtype/pathogenicity , Influenza A Virus, H3N2 Subtype/genetics , Influenza A Virus, H3N2 Subtype/immunology , Influenza A Virus, H3N2 Subtype/pathogenicity , Influenza A Virus, H3N8 Subtype/genetics , Influenza A Virus, H3N8 Subtype/immunology , Influenza A Virus, H3N8 Subtype/pathogenicity , Influenza A Virus, H5N1 Subtype/genetics , Influenza A Virus, H5N1 Subtype/immunology , Influenza A Virus, H5N1 Subtype/pathogenicity , Influenza Vaccines/genetics , Influenza, Human/genetics , Influenza, Human/immunology , Influenza, Human/prevention & control , Influenza, Human/virology , Mice , Vaccines, Attenuated/genetics , Vaccines, Attenuated/immunology , Vaccines, Inactivated/genetics , Vaccines, Inactivated/immunology , Virus Replication/geneticsABSTRACT
The epitope presentation system for ectodomain of M2-protein of influenza A virus (M2e) based on Cowpea Mosaic Virus (CPMV) was constructed for expression in plants Vigna unguiculata. CPMV is widely used as a vector for production of immunogenic chimeric virus particles (CVPs) bearing epitopes of different infectious human and animal pathogens. To produce chimeric CPMV virus particles in plants, two binary vectors were constructed bearing modified gene coding for S-coat protein of CPMV with insertions of M2e epitopes of human influenza and bird influenza viruses. Antigenic and immunogenic properties of CVPs obtained were investigated in mice immunization experiments and it was shown that they can induce anti-M2e IgG production and partial protection mice against challenge with low doses of flu virus. However, low infectivity and immunogenicity of CPMV chimeric particles indicate the need for further optimization of plant virus-based systems for M2e-epitopes presentation to use plants as a possible source of flu vaccines.
