Fig. 3.

Influenza infection and immune cell infiltration in lung tissue sections.

Selected photomicrographs (600x) of formalin-fixed, paraffin-embedded lung tissue sections stained with H&E from (a) animals receiving vehicle control alone at day 3 post-influenza inoculation; (b) B. longum cell wall-treated animals at day 3 post-influenza inoculation; (c) animals receiving vehicle control alone at day 5 post-influenza inoculation; (d) B. longum cell wall-treated animals at day 5 post-influenza inoculation. Neutrophils (red arrows) and macrophages (blue arrows) are identified in the selected photomicrographs. Scale bar=40 µM.