A Study of the Immunogenicity and Protective Properties of Recombinant Influenza Vaccine

The objective of the study is to carry out preclinical research on the immunogenicity and protective properties of the trivalent influenza vaccine AdeVac-Flu in laboratory mice. The AdeVac-Flu vaccine is a mixture of recombinant human adenoviruses of the fifth serotype expressing the hemagglutinin genes of the A/California/07/2009(H1N1), A/Perth/16/2009(H3N2), and B/Brisbane/60/2008 influenza vaccine strains, as well as the molecular adjuvant Immunomax. The Ultravac live influenza vaccine (Microgen, Russia) was used as a reference. To study the protective properties of the vaccine, mice of the line Balb/c were immunized once intranasally and, 28 days after immunization, infected with lethal doses of influenza viruses A H1N1, H3N2, and B. The level of viral shedding from the lungs of mice was assessed on the third and sixth days after infection by titration of lung homogenates on MDCK cell culture. The level of specific antibodies to influenza viruses was determined by indirect ELISA, HAI, and SVN. It was shown that the trivalent influenza vaccine AdeVac-Flu is more immunogenic than the reference drug. The levels of protection against homologous strains of influenza viruses are either slightly less than or comparable to those of the reference drug. In this case, it was shown that the AdeVac-Flu, like the live influenza vaccine, effectively protects mice from a heterologous strain of the influenza virus, although the mice exhibited excretion of the virus from the lungs and a slight decrease in body weight (less than 10%). It has been shown that the AdeVac-Flu vaccine based on recombinant human adenoviruses of the fifth serotype expressing hemagglutinin genes of A/California/07/2009 (H1N1), A/Perth/16/2009 (H3N2), and B/Brisbane/60/2008 influenza viruses has immunogenicity and protective properties in relation to both homologous and heterologous (within the subtype) strains of the influenza virus.