Prolonged presence of effector‐memory CD8 T cells in the central nervous system after dengue virus encephalitis

van der Most, Robbert G.; Murali‐Krishna, Kaja; Ahmed, Rafi

Dengue virus infection in the central nervous system (CNS) of immunized mice results in a strong influx of CD8 T cells into the brain. Whereas the kinetics of the splenic antiviral response are conventional, i.e. expansion followed by a rapid drop in the frequency of specific CD8 T cells, dengue virus‐specific CD8 T cells are retained in the CNS at a high frequency. These CD8 T cells display a partially activated phenotype (CD69(high), Ly‐6A/E(high), CD62L(low)), characteristic for effector‐memory T cells. CD43 expression, visualized by staining with the 1B11 mAb, decreased in time, suggesting that these persisting CD8 T cells differentiated into memory cells. These data add to the growing evidence implicating the CNS as a non‐lymphoid tissue capable of supporting prolonged T cell survival/maintenance.