Candidate vaccine construction against tick-born encephalitis based on hybrid recombinant flagG-protE-protein

Abstract

The present work describes the construction of the gene encoding the recombinant protein flagG­protE, its synthesis, purification and study. The recombinant flagG­protE protein is a promising molecule for developing a candidate recombinant vaccine against tickborne encephalitis by the ability to bind to monoclonal antibodies (MCA) against native protein E of tick­borne encephalitis virus. The antigenic determinants of two recombinant proteins were studied: protE and flagG­protE using a panel of 8 MCA. The recombinant protein protE comprises the tick­borne encephalitis virus envelope protein and the flagGprotE recombinant protein has an additional flagG domain encoding flagellin G of Salmonella typhi. It was found that the MCA tested revealed epitopes on the recombinant protein protE. This indicates that the investigated recombinant protein has an antigenic structure similar to the antigenic structure of the native tick­borne encephalitis virus protein E. In the study of the recombinant protein flagG­protE by the ability to bind a panel of 8 MCA, only five of them react with epitopes of the tested protein. MCA 4F6, 7F10, and 6B9 did not recognize the corresponding epitope in the recombinant flagG­protE protein, while in the recombinant protein protE, these epitopes were detected successfully. Our data indicate that the antigenic structure of recombinant protE­protein can be changed under the influence of the flagellin domain, which in turn can lead to the unavailability of some antigenic determinants. This fact must be taken into account when constructing recombinant molecules with antigenic properties. Nevertheless, the fundamentally important regions in the region of the fusion peptide and III domain are antigenically present on the surface of the recombinant protein. This should ensure the formation of neutralizing antibodies, and the presence of a complete amino acid sequence of protein E in the recombinant protein induces the formation of a T­cell immune response. The emergence of a new generation of vaccines against tick­borne encephalitis with a higher level of safety and immunogenicity will improve the vaccine prevention of the population from tick­borne encephalitis.

Keywords

• flagellin g
• envelope protein
• adjuvant
• tbe
• immunogenicity
• vaccine