Epitope mapping in proteins of hepatitis E virus.

A series of synthetic peptides derived from proteins encoded by open reading frames 2 and 3 (ORF2 and ORF3) of the hepatitis E virus was used in an enzyme immunoassay to determine the localization of epitopes in these proteins. Five peptides spanning almost the entire ORF3 protein sequence and 12 peptides from the ORF2 protein were synthesized. Serum samples collected from outbreaks in three different regions of the world (Turkmenistan, Kenya, and Mexico) were analyzed by a peptide-based enzyme immunoassay. Primary analysis of the peptides was accomplished with the use of serum samples obtained from Middle Asia. Four of 5 peptides from the ORF3 protein and 4 of 12 peptides from the ORF2 protein specifically reacted with antibody from sera of HEV-infected patients. Peptides representing immunodominant epitopes were used for the analysis of serum samples from outbreaks in Kenya and Mexico. The data indicate that these synthetic peptides may be used to develop a diagnostic test to detect antibody to the hepatitis E virus.