In order to determine the viral specificity of the NKG2D-positive CTLs at 7 dpi we costained BILs with anti-CD8, anti-NKG2D, and the TMEV VP2 121-130 -specific tetramer (Beckman Coulter Immunomics, San Diego, CA; 1:100) (Howe et al, 2007) . Flow cytometry revealed that 74 ± 2% of CD45 hi CD8 + cells were VP2-specific ( Figure 1G ), while none of these cells were stained by an irrelevant D b /E7 tetramer (data not shown) (Mendez-Fernandez et al, 2005) . Moreover, 81 ± 2% of the VP2-specific CTLs were also NKG2D-positive ( Figure 1H ), while only 12 ± 2% of the VP2 tetramer-negative CTLs were positive for NKG2D ( Figure 1I ) (n=4 mice; mean ± 95% CI). We conclude that a robust population of NKG2D-positive VP2-specific CTLs are present within the brain at 7 days after infection with TMEV.