Golotin et al.
Recombinant fusion protein joining E protein domain III of tick-borne encephalitis virus and HSP70 of Yersinia pseudotuberculosis as an antigen for the TI-complexes.
biomolecules 2018; 8: 82; doi:10.3390/biom8030082
So far, all licensed TBE vaccines are based on inactivated whole viruses as antigen. The main protective epitopes are located in domain III (DIII) of the envelope glycoprotein E (gE) of the virus. However, DIII alone is not immunogenic due to its low molecular weight. Its immunogenicity can be increased by fusion to the heat shock protein 70 (HSP70) of Yersinia pseudotuberculosis yielding the hybrid protein HSP70/EIII. In mice, this hybrid protein showed two-fold immunogenicity compared to EIII alone. Incorporation of the hybrid antigen into TI-complex resulted in two-fold increase in the levels of anti-EIII antibodies. The TI-complex is an adjuvanted antigen delivery system which can influence the conformation and immunogenicity of protein antigens. The authors concluded that using HSP70 linked to the DIII domain of gE is an effective means for presenting the main epitopes of TBE antigen and the incorporation of the hybrid antigen into the TI-complex further contributes to the development of recombinant TBE vaccines.