ASSESSMENT OF THE ANTIGENIC STRUCTURE OF TICK-BORNE ENCEPHALITIS-VIRUS BY THE USE OF SYNTHETIC PEPTIDES

The feasibility of using synthetic peptides for the identification of individual monoclonal antibody (MAb)-defined epitopes was assessed on the basis of a structural model of the tick-borne encephalitis (TBE) v irus envelope glycoprotein E. For this purpose a series of 19 syntheti c peptides was prepared, covering most of the E protein sequence. Each of the peptides was tested by ELISA for reactivity with 19 protein E- specific MAbs raised against TBE virus strain Neudoerfl. Specific reac tivity was observed with three MAbs and two peptides (representing ami no acids 1 to 22 and 221 to 240, respectively), thus providing new inf ormation on the location of the corresponding epitopes. Specificity wa s confirmed in a competition ELISA by the ability of the peptides to b lock MAb binding to TBE virus antigen. However, in contrast to the oth er MAbs, these peptide-reactive MAbs were not blocked by native virus particles in the competition ELISA, indicating that they do not recogn ize the native conformation of the E protein. These three MAbs also sh owed increased reactivity with denatured forms of the virus in a dot b lot assay. Additionally, they reacted only in ELISA systems in which t he virus was directly coated to the solid phase and thereby presumably partially denatured, but not when a capture antibody was used, which preserves the native antigen conformation. We have thus identified two classes of MAbs, those which recognize the native form and those whic h recognize the denatured form of protein E. The latter may be useful for the analysis of sites probably involved in protein folding and oli gomerization.