Diagnostic immunoassays for tick-borne encephalitis virus based on recombinant baculovirus protein expression

The baculovirus expression system that utilizes Autographa californica nucl ear polyhedrosis virus was used to express the highly antigenic envelope pr otein E of a tick-borne encephalitis (TBE) complex virus, as well as a C-te rminally truncated form of protein E (Etr). The recombinant proteins were p roduced with a histidine-tag at their carboxy-terminus. Protein purificatio n by nickel agarose chromatography resulted in high concentrations of pure Etr protein, but only poor yields of E protein. Therefore, Etr was used to develop a sensitive and specific enzyme-linked immunosorbent assay (ELISA), as well as an immunoblot assay to detect TEE virus-specific antibodies in sera from immunized human blood donors. Sera from non-vaccinated blood dono rs were used as controls. The data show that the recombinant TEE virus-spec ific Etr protein exhibits the antigenic epitopes and conformation necessary for specific antigen-antibody recognition. Thus, the baculovirus expressio n system provides a cheap and easy method to generate recombinant viral ant igens for TEE virus-specific serodiagnosis. (C) 2001 Elsevier Science B.V. All rights reserved.