Fig. 3.

Photomicrographs of the lung sections of H1N1 challenged mice. Lung sections from mice at 6 days post challenge were hematoxylin and eosin stained. Lungs from mice immunized one (a), two (b) or three times (c) with Ad5 [E1-, E2b-]-HA + NA (2 × 10¹⁰ VP total), three times with Ad5 [E1-, E2b-]-HA alone (d) exhibited no signs of H1N1 infection and the airway epithelium remained intact (original magnification 40×). Lung samples from vector control mice (e) and non-immunized mice (f) had dense granulocytic and lymphocytic cell infiltrates.