VARIABILITIES IN THE ANTIGENIC STRUCTURE OF PERSISTING TICK-BORNE ENCEPHALITIS-VIRUS STRAINS

Antigenic variants in the E protein from persisting tick-borne encepha litis (TBE) virus strains were analyzed using monoclonal antibodies (M Abs) to an analogous protein of the reference Sofyin strain. MAbs to s equential epitopes demonstrated their ability to differentiate persist ing TBE virus strains from Sofyin and from each other. Two MAbs (2H3 a nd 13D6) showed a higher neutralizing activity in the interaction with persisting TBE virus variants as compared to the Sofyin strain. Based on the obtained data, a comparison was made of topologically identica l epitopes from the E protein of reference and persisting virus strain s. The possibility of increasing the neutralizing activity of MAbs thr ough alterations in the primary structure of sequential antigenic site s is discussed.