FIG. 6.

Effects of antibiotic treatment on neutrophil infiltration in wild-type and CF mouse small intestine. Mice were untreated (Control) or given oral antibiotics (+Antibiotics) for 3 weeks, and paraffin sections of the central portion of the intestine (jejunum and ileum region) were prepared for neutrophil immunohistochemistry. (A) Untreated wild-type mouse small intestine has some neutrophils, mostly near lymph nodules (dark-staining structures). (B) Antibiotic-treated wild-type mouse intestine does not have appreciably different numbers of neutrophils compared to untreated wild-type mice. (C and E) Untreated CF mouse small intestine has increased neutrophils near lymph nodules, shown in panel C, and in the lamina propria, shown in panel E, compared to untreated wild-type mice. (D and F) Antibiotic-treated CF mouse intestine has fewer neutrophils near lymph nodules, shown in panel D, and in the lamina propria, shown in panel F, compared to untreated CF mice. Representative images from three to five mice per group are shown.