Fig. 5. CD4+ and CD8+ T-cells confer antiviral protection.

CD4+, CD8+, or total T cells were purified via negative selection from the spleens of mock-infected mice or mice that were intraperitoneally infected with 10⁵ PFU WT or DIP 2 mo previously. Three million CD4+ (a), CD8+ (b), or total T (c) cells were transferred to a congenic mouse by tail vein injection. The recipient mice were intranasally challenged with 5 × 10³ PFU WT at 24 h post-transfer. Latent infection in the spleen at 14 d post challenge was measured by infectious center assay. Pooled data from 2 independent experiments using different numbers of mice for each replicate. Data for individual mice, means, and SD indicated by error bars were plotted. Statistical significance was analyzed by a two-tailed Student’s t-test. P < 0.05*, P < 0.01**, P < 0.001***, and P < 0.0001****.