FIG. 4.

Lung histopathology of BALB/c mice infected with RSV. Mice were infected i.n. with 5 × 10⁵ PFU (A), 10⁶ PFU (B), and 10⁷ PFU (C) of sucrose-purified RSV or were sham infected (D). At day 1 postinfection mice were killed and lungs were removed, fixed in 10% buffered formalin, and embedded in paraffin. Multiple 4-μm-thick sections were stained with H&E. Original magnification, ×50.