IDENTIFICATION OF AN IMMUNODOMINANT NEUTRALIZING AND PROTECTIVE EPITOPE FROM MEASLES-VIRUS FUSION PROTEIN BY USING HUMAN SERA FROM ACUTE INFECTION

Polyclonal sera obtained from African children with acute measles were used to screen a panel of 15-mer overlapping peptides representing th e sequence of measles virus (MV) fusion (F) protein. An immunodominant antigenic region from the F protein (p32; amino acids 388 to 402) was found to represent an amino acid sequence within the highly conserved cysteine-rich domain of the F protein of paramyxoviruses. Epitope map ping of this peptide indicated that the complete 15-amino-acid sequenc e was necessary for high-affinity interaction with anti-MV antibodies. Immunization of two strains of mice with the p32 peptide indicated th at it was immunogenic and could induce antipeptide antibodies which cr oss-reacted with and neutralized MV infectivity in vitro. Moreover, pa ssive transfer of antipeptide antibodies conferred significant protect ion against fatal rodent-adapted MV-induced encephalitis in susceptibl e mice. These results indicate that this epitope represents a candidat e for inclusion in a future peptide vaccine for measles.