title: The effect of gamma-irradiation conditions on the immunogenicity of whole-inactivated Influenza A virus vaccine.
abstract: Gamma-irradiation, particularly an irradiation dose of 50kGy, has been utilised widely to sterilise highly pathogenic agents such as Ebola, Marburg Virus, and Avian Influenza H5N1. We have reported previously that intranasal vaccination with a gamma-irradiated Influenza A virus vaccine (γ-Flu) results in cross-protective immunity. Considering the possible inclusion of highly pathogenic Influenza strains in future clinical development of γ-Flu, an irradiation dose of 50kGy may be used to enhance vaccine safety beyond the internationally accepted Sterility Assurance Level (SAL). Thus, we investigated the effect of irradiation conditions, including high irradiation doses, on the immunogenicity of γ-Flu. Our data confirm that irradiation at low temperatures (using dry-ice) is associated with reduced damage to viral structure compared with irradiation at room temperature. In addition, a single intranasal vaccination with γ-Flu irradiated on dry-ice with either 25 or 50kGy induced seroconversion and provided complete protection against lethal Influenza A challenge. Considering that low temperature is expected to reduce the protein damage associated with exposure to high irradiation doses, we titrated the vaccine dose to verify the efficacy of 50kGy γ-Flu. Our data demonstrate that exposure to 50kGy on dry-ice is associated with limited effect on vaccine immunogenicity, apparent only when using very low vaccine doses. Overall, our data highlight the immunogenicity of influenza virus irradiated at 50kGy for induction of high titre antibody and cytotoxic T-cell responses. This suggests these conditions are suitable for development of γ-Flu vaccines based on highly pathogenic Influenza A viruses.
authors.affiliation: Research Centre for Infectious Diseases, and Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia.
authors.forename: Shannon C
authors.initials: SC
authors.lastname: David
authors.affiliation: Research Centre for Infectious Diseases, and Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia.
authors.forename: Josyane
authors.initials: J
authors.lastname: Lau
authors.affiliation: Research Centre for Infectious Diseases, and Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia.
authors.forename: Eve V
authors.initials: EV
authors.lastname: Singleton
authors.affiliation: Research Centre for Infectious Diseases, and Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia.
authors.forename: Rachelle
authors.initials: R
authors.lastname: Babb
authors.affiliation: Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia.
authors.forename: Justin
authors.initials: J
authors.lastname: Davies
authors.affiliation: Research Centre for Infectious Diseases, and Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia; Gamma Vaccines Pty Ltd, Mountbatten Park, Yarralumla, ACT 2600, Australia.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Hirst
authors.affiliation: Research Centre for Infectious Diseases, and Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia.
authors.forename: Shaun R
authors.initials: SR
authors.lastname: McColl
authors.affiliation: Research Centre for Infectious Diseases, and Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia.
authors.forename: James C
authors.initials: JC
authors.lastname: Paton
authors.affiliation: Research Centre for Infectious Diseases, and Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia; Gamma Vaccines Pty Ltd, Mountbatten Park, Yarralumla, ACT 2600, Australia. Electronic address: mohammed.alsharifi@adelaide.edu.au.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Alsharifi
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis*; D004285:Dogs; D004306:Dose-Response Relationship, Immunologic; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005720:Gamma Rays; D007115:Immunization Schedule; D000071497:Immunogenicity, Vaccine; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects* / Q000276:immunology / Q000472:pathogenicity; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000528:radiation effects*; D061985:Madin Darby Canine Kidney Cells; D051379:Mice; D008807:Mice, Inbred BALB C; D009976:Orthomyxoviridae Infections / Q000276:immunology / Q000401:mortality / Q000517:prevention & control* / Q000821:virology; D016019:Survival Analysis; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000821:virology; D014611:Vaccination; D064166:Vaccine Potency; D015164:Vaccines, Inactivated
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines; D015164:Vaccines, Inactivated
keywords: Gamma-irradiation; Immunogenicity; Influenza A virus; Protective immunity