Identification of Immune Responses to Japanese Encephalitis Virus Specific T Cell Epitopes

Due to the similarity between the dengue (DENV) and the Japanese encephalitis virus (JEV) there is potential for immune cross-reaction. We sought to identify T cell epitopes that are specific to JEV and do not cross react with DENV. 20mer peptides were synthesized from regions which showed >90% conservation. Using IFNγ cultured ELISpot assays, we investigated JEV-specific T cell responses in DENV and JEV non-immune individuals (DENV JEV = 21), JEV seronegative and had not received the JE vaccine, but who were DENV seropositive (DENV JEV = 22), JEV (seropositive for JEV and had received the JE vaccine), but seronegative for DENV (DENV JEV = 23). We further assessed the responses to these peptides by undertaking IFNγ assays and flow cytometry. None of DENV JEV individuals responded to any of the 20 JEV-specific peptides. High frequency of responses was seen to 6/20 peptides by individuals who were JEV but DENV , where over 75% of the individuals responded to at least one peptide. P34 was the most immunogenic peptide, recognized by 20/23 (86.9%) individuals who were DENV JEV , followed by peptide 3 and peptide 7 recognized by 19/23 (82.6%). Peptide 34 from the NS2a region, showed