Identification of immunodominant, group-specific and subcomplex-specific, continuous epitopes in the core regions of Japanese encephalitis virus using synthetic peptides

Two flaviviruses, Japanese encephalitis (JE) virus and Dengue (DEN) virus which have high pathogenicity for humans, continue to pose a serious public health problem in tropical and subtropical countries of the world. In order to identify the immunodominant B-cell epitopes for diagnostic application, we have prepared a series of 15-mer synthetic peptides from JE virus core protein based on computer analysis. Four linear, immunodominant epitopes corresponding to amino acids 91–105 (P78), 1–15 (P73), 8–22 (P74), and 34–48 (P75) of JE virus core proteins were identified by employing an enzyme-linked immunosorbent assay (ELISA), using high-titered immune sera from JE-vaccinated children. P78 was found to be the most immunodominant. The sero-specificity of these peptides was tested by binding to seroconverted samples from JE and DEN-1 patients. P78 and P74 belonged to group-specific epitopes which reacted with both JE and DEN-1 patient sera. P73 and P75 belonged to subcomplex-specific epitopes which reacted only with JE but not with DEN-1 patient sera. The study suggests that these peptides corresponding to the immunodominant epitopes of JE virus core protein might have the potential to be used as peptide-based diagnostic reagents for the detection and differentiation of JE and DEN antibody responses.