Figure 3.
Diminished clearance of L. monocytogenes in the distal small intestine of MyD88-deficient mice. (A) MyD88+/+ and MyD88−/− mice were infected with 1010 L. monocytogenes by gavage, and CFUs in the proximal (pro) and distal part of the small intestinal wall were determined 24 h p.i.; n = 8 mice/group. (B) Segments from proximal (pro) or distal small intestine were cultured in media containing 2,000 L. monocytogenes. After 4 h, bacterial burden in the supernatant was determined. Values are representative of two individual experiments. (C) Schematic representation of the in vivo luminal killing assay. (D) Bioluminescence imaging of luminescent L. monocytogenes in ileal loops of MyD88+/+ and MyD88−/− mice. Luminescent L. monocytogenes (2.5 × 105) was injected into ileal loops of MyD88+/+ and MyD88−/− mice and imaged 30 min (top) and 2 h (bottom) after injection with an IVIS Imaging System. One representative mouse per group is shown. n = 5. (E) 1,000 L. monocytogenes were injected into ileal loops of wt, MyD88−/−, TNF−/−/IFN-γ−/−, and Rip2−/− mice. 2 h after injection, the isolated section of the intestine was harvested and CFUs in the luminal fluid were detected. n = 3 for MyD88−/−; n = 5–9 for all other groups. Bacterial numbers are expressed as the percentage of recovered L. monocytogenes. *, P ≤ 0.05, ***, P < 0.001. Error bars represent the SD.