Activated CD56(+) lymphocytes (NK+NKT) mediate immunomodulatory and anti-viral effects during Japanese encephalitis virus infection of dendritic cells in-vitro.

Japanese encephalitis virus (JEV) remains one of the major causative agents of pediatric encephalitis. Interaction of dendritic cells (DCs) with innate lymphocytes (NK and NKT) represents a crucial event during anti-viral innate immune response. In the current study, we have tried to understand the interaction between JEV, human monocyte derived DCs (MDDCs), and CD56(+) cells (NK+NKT) in-vitro. We have used two JEV strains (i) JE057434 (neurovirulent, wild-type) and (ii) SA14-14-2 (non-neurovirulent, live-attenuated vaccine) to investigate the effect of viral virulence on the functional status of primary human MDDCs. Our preliminary results indicate that replicating JEV induces MDDCs maturation via PI3K and p38 pathways. We also show that the presence of IL2-activated CD56(+) cells impart both immunomodulatory and anti-viral effects on DCs infected with JEV. Mechanistic studies illustrate that, IL2-activated CD56(+) lymphocytes mediated immunomodulation occurs through direct cell-to-cell contact and TNFα, while the anti-viral effect is dependent on direct cell-to-cell contact.