Epithelial cell-derived neutrophil-activating protein-78 (ENA-78) is a neutrophil-directed C-X-C chemokine. We report that Caco-2 and T84 human intestinal epithelial cells produce ENA-78 after stimulation by interleukin (IL)-1 beta or tumor necrosis factor-alpha. Caco-2 cells show increased IL-8 production at 4-12 h and increased ENA-78 production at 8-24 h after cytokine stimulation. Immunohistochemical studies in normal human colon and in ulcerative colitis demonstrate ENA-78 immunoreactivity principally associated with crypt epithelial cells. Furthermore, human colonic tissues from patients with ulcerative colitis show elevated levels of ENA-78 mRNA (24-fold increase, P < 0.01) and protein (4-fold increase, P < 0.05) compared with normal controls. Thus ENA-78 is produced in normal colon and in ulcerative colitis and is predominantly of enterocyte origin. The kinetics of ENA-78 induction in human colon epithelial cell lines are delayed and prolonged compared with IL-8. We propose that ENA-78 and IL-8 serve complementary and sequential roles in neutrophil recruitment in ulcerative colitis. ENA-78 as an enterocyte-derived, neutrophil-activating chemokine may be especially important in neutrophil recruitment from the lamina propria into the epithelial layer.