Kinetics of the LCMV specific CD8 T cell response. Mice were seeded with Thy1.1+DbGP33–41 specific CD8+ T cells (P14 cells) and infected one day later with 2 × 106 PFU of Armstrong or clone 13. Mononuclear cells were isolated from the A) spleen, B) liver and C) CNS at the indicated time points following intracardiac perfusion to remove contaminating blood cells. The absolute number of P14 cells in each tissue was determined by flow cytometry. A log fewer CTL was found in the CNS of clone 13 infected mice at day 8 p.i. (first black arrow), and a significant elevation in P14 cells was observed at day 71 (second black arrow). Values represent the mean ± standard deviation (SD) of three mice per group at each time point. No significant differences were noted in the spleen or liver (two representative peripheral tissues). D) To confirm the findings in panel C, CNS P14 cells were quantified in a separate experiment (n = 4 to 7 mice per group) at an early (day 8) and late (day 70) time point post-infection. Note the significant reduction in P14 cells at day 8 and the elevation at day 70 when clone 13 infected (gray bars) were compared to Armstrong infected (black bars) mice. Data are represented as the mean ± SD. Asterisks denote statistically significant (p < 0.05) differences between Armstrong and clone 13 infected mice. E) The absolute number of CD8+Thy1.1+ P14 cells (open circles) in the CNS of clone 13 infected animals (as shown in panel C) is plotted against the titer of infectious virus (black circles) in the brain at various time points after clone 13 infection (as shown in Table 1). Note that the elevation in CNS CTL numbers coincides with a reduction in infectious virus as determined by plaque assay.