TICK-BORNE ENCEPHALITIS-VIRUS ENVELOPE PROTEIN E-SPECIFIC MONOCLONAL-ANTIBODIES FOR THE STUDY OF LOW PH-INDUCED CONFORMATIONAL-CHANGES AND IMMATURE VIRIONS

A set of ten monoconal antibodies (mabs) specific for the tick-borne e ncephalitis (TBE) virus envelope protein E were prepared and character ized with respect to their functional activities, the location of thei r binding sites on protein E and the involvement of their epitopes in acid pH-induced conformational changes and interactions with the precu rsor to the membrane protein (prM) in immature virions. The majority o f these mabs mapped to the previously defined antigenic domain A. All of the mabs recognize parts of the E protein which undergo low pH-indu ced structural rearrangements believed to be necessary for the fusion activity of the virus, and six of the mabs define epitopes which are a ffected by the prM-E interaction in immature virions. They are therefo re of potential value as specific reagents for studying the structure and function of protein E, as well as the function of the prM-E associ ation. Five of the mabs exhibited neutralizing activity, and can there fore be used for the selection of escape mutants.