SELL and skin infection: To determine whether CD62L was required for naïve CD8+ T cells to become activated during VacV skin infection, equal numbers of naïve WT (Thy1.1/1.2) and CD62L-/- P14 CD8+ T cells (Thy1.1/1.1) were transferred into naïve B6 mice (Thy1.2/1.2) and infected with either VacV-GP33 on the skin or LCMV by i.p. injection.