Fig. 7.

Pretreatment of mice with PI protects against subsequent RSV infection. Balb/C mice (five to eight per group) were anesthetized and inoculated intranasally with 50 μl PBS containing no additions (CONL), or 1 × 10⁷ RSV (RSV), or 1 × 10⁷ RSV + 600 μg PI (RPI), or PI alone (PI). An additional group of mice was anesthetized and pretreated with 600 μg PI 2 h before the RSV treatment (pRPI). After 5 days, the mice were euthanized and the lungs were lavaged with 1ml of saline. The recovered lavage solution was centrifuged to produce a cell pellet and supernatant. The mice were dissected and the lungs excised, and the left lobe was processed for quantifying infectious particles by plaque assay. A: The total cells recovered from lavage. B: The neutrophil and lymphocyte populations recovered in the cell pellet. C: The IFN-γ levels. D: The RSV plaques recovered in homogenates of the left lung. Data are from three independent experiments, and the asterisk indicates P < 0.01 when comparing RSV with either RPI or pRPI conditions.