The article discusses several studies that shed light on the exact location of primary CD8+ T-cell activation in lymph nodes and on memory CD8+ T-cell reactivation in peripheral tissues. It was found that infected cells can be seen in a continuous sheet below the lymph node sub-capsular sinus (SCS) within 2-3 hours of virus inoculation. The studies also showed that antigen encounter in peripheral tissues can result in the reactivation of memory CD8+ T-cells.