Fig 3.

Immunohistochemistry. BALB/c mice were sacrificed at day 5 after the initial inoculation. (A) Lung from BALB/c mouse inoculated with DMEM only (no virus); (B) lung from BALB/c mouse inoculated with virus but not incubated with primary antibody; (C) NL/1/00-infected BALB/c mouse lung (arrows, plentiful antigens detected at the luminal surface and alveoli); (D) M2-infected BALB/c mouse lung (arrows, antigens detected at the luminal surface; fewer antigens were detected in alveoli); (E) WT-infected BALB/c mouse lung (arrows, antigens detected at the luminal surface). Magnifications, ×100 (A and B) and ×200 (C to E).