ANALYSIS OF THE NEUTRALIZING ANTIBODY-RESPONSE TO THE MEASLES-VIRUS USING SYNTHETIC PEPTIDES OF THE HEMAGGLUTININ PROTEIN

Infection or immunization with measles virus induces a protective immu ne reaction including neutralizing antibodies against the haemagglutin in and fusion protein. The reactivity of the polyclonal IgG response o f sera obtained from late convalescent donors was studied, using overl apping 15mer peptides covering the complete sequence of the measles vi rus haemagglutinin. Most sera reacted with a similar set of peptides g enerating a characteristic binding pattern. The reactive peptides corr espond to a region mediating cell hemolysis (aa310-325), to regions wh ich serve as targets to neutralizing antibodies and to a putative tran smembrane region (aa35-58). The latter region contains also a human T- cell epitope providing evidence of a non-random association of T- and B-cell epitopes. We also immunized different strains of mice and rabbi ts with measles virus. In contrast to the human sera, animal sera with strong neutralizing activities did not react with any of the H-protei n peptides. The mostly weak reactivities with the linear sequences con trast with the strong neutralizing activities of the human or animal a ntibodies, suggesting that these primarily recognize the fusion protei n or conformational epitopes of the haemagglutinin protein.