FIG. 5.

Mucosal integrity and barrier function. Immunofluorescence staining of colon sections for CD3, IL-17, and ZO-1 at the time of euthanasia. For each marker, five randomly chosen fields were analyzed per animal. (A) Average counts of IL-17 (left graph)- and ZO-1 (right graph)-positive cells per square millimeter colon. Differences in the frequencies of IL-17⁺ or ZO-1⁺ cells between the groups were assessed by the nonparametric Mann–Whitney test. (B) Images of individual animals representative of infants in the mock (left), IM-immunized (middle), or O + IM-immunized infants (right). The top row shows images taken with a 20 × objective. The lower row images show a higher magnification (63 × ) of the white box area indicated in the respective top images. Green and red arrows indicate CD3⁺ T cells or IL-17⁺ cells, respectively; yellow arrows point to CD3⁺IL-17⁺ T cells. (C) ZO-1 staining in colon sections (10 × ). The scale bar for each image is provided in the lower right-hand corner. IL, interleukin; ZO-1, zonula occludens-1.