Detection of spirochetes by immunohistochemistry in tissues from MyD88^−/− but not WT mice.

<p>In the epididymis (A–C; 21 days post inoculation (DPI)), spirochetes are present in large numbers in inflamed foci of MyD88^−/− mice (arrow, A) and occasionally in non-inflamed regions (arrow, B). No spirochetes are visualized even in inflamed regions of WT mice (C). In the rectum from a MyD88^−/− mouse (D; 84 DPI) the interstitium is swollen with an inflammatory infiltrate containing many spirochetes; numerous spirochetes also are evident within the rectal epithelium. In contrast, the rectum of the WT animal (E; 21 DPI) is normal. Spirochetes are evident within the submucosa and in deeper layers of the vaginal epithelium of the MyD88^−/− (F; 84 DPI) but not in the WT (G; 84 DPI) mouse. Spirochetes are present in the epithelium of the bulbourethral gland (H; 84 DPI) and myovascular tissue of the corpus cavernosum (I; 10 DPI) in MyD88^−/− mice. Bars = 5 µm in panels A,B,I; 10 µm in panels C and H; and 20 µm in panels D–G.