Hb-infected CD11cTg/Rag2−/− mice that received CD4+CD45RBhi cells (AT) developed colitis (A) compared with Hb infected- CD11cNtg/Rag2−/− mice given AT, showing formed feces in a normal colon (B). Histological sections of the lesions in the cecum (C) and colon (E) of CD11cTg/Rag2−/− mice comprised pronounced crypt-proliferation and infiltration of lymphocytes, macrophages and neutrophils in lamina propria and submucosa, as well as severe submucosal edema, resulting in distortion and obliteration of the normal mucosal architecture, as seen in the cecum (D) and colon (F) of CD11cNtg/Rag2−/− mice. All microphotographs are shown at 10× magnification.