FIG. 3.

Tir localization with EHEC O157:H7 on infected tissue sections, as detected by immunofluorescence. Streptomycin-treated mouse, cesarean-derived/colostrum-deprived piglet, and neonatal calf were fed EHEC O157:H7 strain 86-24 Str^r. Sections of infected intestine were immunostained with anti-Tir and anti-O157 antisera. Representative images from EHEC O157:H7-infected mouse (top row), calf (second row), and pig (third row) are shown for stained O157 (first column) and stained Tir (second column). Images in the bottom row were taken from a piglet infected with normal enteric E. coli strain 123. Immunostaining patterns for O157 and Tir were overlaid (third column) to demonstrate the correlation between bacteria and Tir. Phase-contrast micrographs overlaid with the combined fluorescence (fourth column) depict the orientation of the epithelial cell (E) and lumen (L). Representative adherent bacteria and associated immunostained Tir are indicated by blue arrows. Bar, 1 μm.