Plaque formation by Japanese encephalitis virus bound to mosquito C6/36 cells after low pH exposure on the cell surface.

Japanese encephalitis virus (JEV) formed plaques in mosquito C6/36 cell layers after adsorption on the cell surface and exposure to pH values lower than 6.2. The number of plaques decreased within pH ranges from 7.4 to 6.4, but increased within pH ranges from 6.2 to 5.8. Plaque formation was prevented by treatment of the virus with a JEV-neutralizing monoclonal antibody, 503, after virus adsorption. Plaque formation was not affected by pretreatment with a specific V-ATPase inhibitor, bafilomycin A1. The results indicate that JEV successfully fused with the C6/36 cell membrane under acidic conditions below pH 6.2, which in turn led to plaque formation in C6/36 cell layers. These results suggest that productive JEV infection occurs at the C6/36 cell surface via the fusion between JEV and the cell membrane.