Role of Natural Killer and Gamma-Delta T cells in West Nile Virus Infection

Wang, Tian; Welte, Thomas

NK cells have been reported to be involved in the host immunity to infection of many flaviviruses, including yellow fever virus, Japanese encephalitis virus, tick-borne encephalitis virus, dengue virus, and WNV [23] [24] [25] [26] . Vargin et al. [25] were the first to report that infection of mice with WNV was accompanied by the temporary activation of NK cells in the spleen. Similar to other innate immune cells, such as monocytes and dendritic cells (DCs), NK cells can migrate into the CNS as the virus invades the brain, following a systemic infection in mice [27] . They presumably play an important role in the control of WNV infection by their recognition and elimination of infected cells, as demonstrated in ex vivo cytotoxicity assays reported by several groups. In one study [28] , brain leukocytes isolated from WNV-infected mice displayed an NK cell phenotype and had the ability to lyse WNV-infected and non-infected cell lines in vitro. Another group showed that active human NK cells, which resulted from co-cultivation of peripheral blood mononuclear cells (PMBCs) with radiation-killed K562-mb15-41BBL stimulatory cells inhibited WNV infection in Vero cells [29] .