Diversification in the CNS immune repertoire during the reanimation phase. A) The CD8 to CD4 T cell ratio was calculated for spleen, liver, and CNS of clone 13 infected mice over time by dividing the absolute number of CD8 T cells extracted from each tissue by the absolute number of CD4 T cells. Note that the ratio is highest in the CNS at early time points post-infection. As the number of CD4 T cells increase in the CNS over time this ratio becomes similar to that observed in peripheral tissues. B) Mononuclear cells were extracted from spleen (data not shown), liver (data not shown) and CNS of clone 13 infected mice (n = 4 mice per group) at day 8 (exhaustion phase) or day 69 (reanimation phase) p.i. to define the immune repertoire. Multi-parameter digital flow cytometry permitted analysis of the entire immune repertoire from a single sample for each tissue. The frequencies of both innate and adaptive immune cells are represented as pie diagrams. Statistically significant increases (p < 0.05) at day 69 are denoted by asterisks. C) The frequencies shown in panel B were used to calculate the absolute number of the respective CNS cell populations in clone 13 infected mice. Note the statistically significant (p < 0.05) increase in the number of CD4 T cells and B cells in the CNS at day 69. The bars represent mean ± SD at each time point. Asterisks denote a statistically significant difference between day 8 and day 69.