Rizzo et al.
A method for rapid and high-yield production of the tick-borne encephalitis virus E and DIII recombinant proteins in E. coli with preservation of the antigenic properties.
Ticks Tick Borne Dis., in press, doi.org/10.1016/j.ttbdis.2019.04.021
The glycoprotein E (gE) is the dominant immunogen of TBE virus and other related flaviviruses and therefore, immunodiagnostic kits to detect TBE antibodies are based on this antigen. However, cross-reactive epitopes within the gE can lead to false-positive reactions using commercial ELISAs (see Snapshot week 12/2019). Rockstroh et al. (see Snapshot week 18/2019) have used mutated gE produced in insect cells to develop more specific ELISAs. Here, the recombinant expression in E. coli of gE and the DIII domain which carry TBE virus specific epitopes has been described. The antigens were produced in high amounts fused to gluthation S-transferase. The hybrid proteins form inclusion bodies which can be solubilised in high molar urea solution. These recombinant (non-glycosylated) proteins were immunoreactive with animal and human TBE specific sera. In an ELISA, the recombinant DIII domain showed a high specificity with TBE positive sera from patients and very low reactivity with negative control sera. Thus, based on this approach or that described in Snapshot week 18/2019, one can expect that novel, very specific ELISAs may be developed soon to analyse human sera for TBE or other flavivirus infections.