FIG. 3.
Immunostaining of viral antigens in lung and brain from mice infected with 1,000 MID50 of HK/483 virus. (A) Immunostaining in bronchial epithelium and subepithelial tissue from a mouse that succumbed to infection on day 7 p.i. (B) Higher magnification of a bronchus showing mainly nuclear, and to a less extent cytoplasmic, staining of bronchial epithelial cells. Note immunostaining in association with necrotic detached epithelial cells in bronchial lumen. (C) Brain collected on day 6 p.i. showing a focus of antigen-positive cells. (D) High-power magnification showing nuclear and cytoplasmic immunostaining of glial cells and neurons (naphthol-fast red with hematoxylin counterstain; original magnifications, ×50 [A], ×158 [B], ×50 [C], and ×158 [D]).