FIG. 6.

Salmonella-induced Cox-2 expression is restricted to the epithelium. Human intestinal xenografts infected for 2 h with Salmonella were embedded in OCT compound and snap-frozen in methylbutene-dry ice. Histological analysis of control and Salmonella-infected tissue illustrates that the induction of Cox-2 expression is restricted to the epithelium and occurred along the entire crypt-villus axis. (A) Control tissue with a low level of background staining for Cox-2. (B) Cox-2 staining in tissue infected with Salmonella for 2 h.