IDENTIFICATION BY MONO CLONAL ANTIBODIES OF A NEW EPITOPE IN THE GLYCO PROTEIN COMPLEX OF SINDBIS VIRUS

Mouse monoclonal antibodies against a deletion mutant of Sindbis virus were produced and characterized in order to determine the fine mapping and functional activities of single viral epitopes. All monoclonal antibodies so far tested showed a certain degree of reciprocal competition and were directed against an antigenic determinant which was present only on the undissociated complex of the E1 and E2 glycoproteins. A biological assay measuring viral hemagglutination showed no decrease in the titer of viral samples preincubated with monoclonal antibodies. Conversely, a reduction in viral infectivity was demonstrated, particularly with 2 of these antibodies. Evidently, the antibodies which were characterized seem to recognize a new epitope which is represented on both glycoproteins on the surface of this mutant of Sindbis virus.