Representative HSP-70–immunostained lung sections obtained following administration of AdGFP or AdHSP. C48 indicates 2CLP with virus administration; tissue was fixed 48 hours afterward. Primary antibody was polyclonal goat anti-rat HSP-70; secondary antibody was rabbit anti-goat IgG conjugated to horseradish peroxidase. Detection was performed with immunoperoxidase/avidin/biotin and metal-enhanced 3,3-diamino-benzidine. Arrows indicate HSP-70 staining, primarily in type II pulmonary epithelial cells.