Fig. 5.

Chronic selective targeting of IEC by endogenous TNF in Tnf^ΔARE/+ mice is not sufficient for the development of intestinal pathology. (A–C) Histological examination of the ileum of 8-mo-old Tnf^ΔARE/+VillinCreTnfRI^{flxneo/flxneo} mice and littermate controls. (A) Tnf^ΔARE/+VillinCreTnfRI^{flxneo/flxneo} mice that express TNFRI selectively in IEC show normal tissue structure without signs of inflammation or tissue damage. (B) Severe intestinal pathology characterized by extensive mucosal and submucosal inflammation in positive-control Tnf^ΔARE/+TnfRI^flxneo/+ mice. (C) Negative-control Tnf^ΔARE/+TnfRI^{flxneo/flxneo} mice that do not express TNFRI appear normal. Paraffin sections were stained with H&E. (Scale bars: 100 μm.) (D) Incidence of IBD pathology in the ileum of Tnf^ΔARE/+VillinCreTnfRI^{flxneo/flxneo} mice and littermates at age 8 and 12 mo.