Figure 1.

Absence of tissue injury during viral clearance of the persistently infected brain. (A) Cell death was assessed in the brains of mice with fatal meningitis or after adoptive immunotherapy by performing TUNEL staining. 9 d after adoptive immunotherapy, frozen sagittal brain sections from LCMV carrier mice were stained to detect apoptotic cells and cell nuclei (DAPI) and compared with uninfected control tissue, as well as brain sections from symptomatic day 6 mice with LCMV meningitis (positive control for apoptosis). The bar graph depicts the mean ± SD for each group, and each symbol is an individual mouse (n = 4 mice per group). (B) TUNEL staining was performed on liver tissue extracted from the same groups of mice as above. Note the increased number of apoptotic cells on the liver section from the day 9 immunotherapy recipient when compared with the naive and day 6 meningitis tissues. (C–E) Vascular leakage was assessed using an Evans Blue assay at day 9 (C and E) and day 30 (D) after immunotherapy in the brain (C and D) and liver (E). Naive and LCMV carrier mice not receiving immunotherapy served as negative control for this experiment. Mice with LCMV meningitis at day 6 after infection served as a positive control for vascular leakage in the brain. Bar graphs show the mean ± SD for each group (n = 4 mice per group). All data shown in this figure are representative of three independent experiments. Asterisks denote statistical significance (*, P < 0.05).