Identification of H-2d-restricted, NS3-specific CD4 and CD8 T-cell Epitopes in Japanese Encephalitis Virus Infected Mice (105.25)

Japanese encephalitis virus (JEV) is the agent to cause the disorder of central nervous system (CNS) or even death. Neutralizing antibodies is believed to play a major role to prevent JEV entry to CNS. The importance of T-cell responses in the control of JEV infection is not clear. In addition, the presence of heterologous suboptimal neutralizing antibodies among between JEV and other flaviviuses may enhance viral infection. A peptide vaccine constituted with both CD4 and CD8 T cell epitopes to elicit a Th1-type response can provide an alternative solution to reduce the impact of heterologous suboptimal neutralizing antibodies. Total 40 and 31 of MHC-I and II peptides were predicted and used in these study. Spleen cells harvested from NS3 DNA vaccinated or JEV-infected BALB/c mice were stimulated and the IFN-gamma production was detected by ELISPOT assay. The mixture of Kd and Ld-restricted peptides showed the stronger ability to stimulate IFN-gamma production than Dd. Four individual MHC-I restricted peptides were identified. To prove the peptide is CD4 or CD8-dependent, different cell populations were depleted by magnetic beads before performing ELISPOT assay, and all 4 peptides showed a CD8-dependent pattern. For MHC-II, a similar strategy was used and three IFN-gamma stimulating Ad-restricted peptides were mapped. A peptide based JEV vaccine based on this study will be used to test the immunogenicity and protection in a mouse model.