Recombinant adenovirus expressing the NS1 nonstructural protein of tick-borne encephalitis virus: Characteristics of immunological basis of antiviral effect

Recombinant adenovirus expressing NS1 nonstructural protein of tick-borne encephalitis (TBE) virus (Rad 51) protected mice from many strains of TBE and Omsk hemorhagic fever (OHF) viruses, but virtually did not protect them from Negishi virus. During combined use of whole-virion inactivated TBE vaccine and Rad 51 the recombinant adenovirus notably potentiated the protective effect of the traditional vaccine. The results of adaptive transfer of immunological material from mice infected with Rad 51 showed that both the vaccinated animals' sera and the pool of T and B cells partially protected the recipient mice from lethal TBE infection. NS1 protein expressed by adenovirus increased the level of the key interleukins (IL) interferon, tumor necrosis factor, IL-1 beta, IL-2, and, probably, IL-4. Vaccination of mice with Rad 51 resulted in the appearance of antibodies to NS1 protein in rather high titers. The prospects of using Rad 51 as a vaccine against TBE are discussed.