EPITOPE ANALYSIS OF TICK-BORNE ENCEPHALITIS (TBE) COMPLEX VIRUSES USING MONOCLONAL-ANTIBODIES TO ENVELOPE GLYCOPROTEIN OF TBE VIRUS (PERSULCATUS SUBTYPE)

The arrangement of envelope protein epitopes of tick-borne encephaliti s viruses (TBEV) (persulcatus or eastern subtype, Sofjin strain and ri cinus or western subtype, Minsk-256 strain) and Kyasanur Forest diseas e virus (KFDV) was investigated using competitive binding of monoclona l antibodies against the Sofjin E protein. The E protein of TBEV Sofji n strain forms three antigenic domains: E1, E2 and E3, represented by 12, 9 and 2 epitopes respectively; two additional epitopes stand alone . Domains E1 and E2 are heterogeneous. On the epitope map of the Minsk -256 strain domain E3 remains intact, domains E1 and E2 overlap and th e relative arrangement of virus-neutralizing epitopes from E1 and E2 d omains is changed. The epitope map of KFDV is significantly dissimilar to TBEV. The viruses can be distinguished by epitopes with identical serological reactivity. A satisfactory agreement between our epitope m aps and previously published antigenic models of flavivirus envelope p rotein (Guirakhoo et al., 1989; Mandl et al., 1989a) was observed. The main difference of our map is that domains corresponding to domains B and C (Sofjin strain) and A, B and C (Minsk-256 strain) in Heinz's mo del are overlapping. The results of competition analysis depend on the nature of the antigen (virion or purified protein) and the immunoassa y technique.