Evidence for Latency of Japanese Encephalitis Virus in T Lymphocytes

Activation of latent Japanese ncephalitis virus (J EV) in the spleen has been studied by co-cultivation with allogeneic or syngeneic cells. Activated virus was isolated by co-cultivation from T lymphocytes ofspleen, 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. Following primary infection of a host with certain viruses, a lifelong relationship can be established. Latent infection can be established inmacrophages bycytomegalovirus (Brautigam et al., 1979), in T lymphocytes by human immunodeficiency virus (Harper et al., 1986), in B lymphocytes by Epstein-Barr virus (Klein et al., 1976) and in sensory ganglion and mouse footpad cells by herpes simplex virus (Cook et al., 1974; Clements & Subak-Sharpe, 1988). Japanese ncephalitis virus (JEV) has the ability to establish a latent infection in mice afte