Abstract
Activation of latent Japanese encephalitis virus (JEV) in the spleen has been studied by co-cultivation with allogeneic or syngeneic cells. Activated virus was isolated by co-cultivation from T lymphocytes of spleen, as shown by indirect immunofluorescence or by inoculation into mice. The B lymphocytes and macrophages of latently infected mice did not reactivate the virus. A higher proportion of Lyt 1 cells than Lyt 2 cells were harbouring JEV as shown by indirect immunofluorescence. The spleen cells from latently infected mice elicited the lymphoproliferative response but this was much lower than that observed in the controls. These findings suggest the establishment of latent JEV infection in T lymphocytes.