Review article: Effector role of epithelia in inflammation--interaction with bacteria

The common response to infection is infiltration of the affected tissue by inflammatory cells. It is now recognized that the epithelium plays a crucial role in this immunological process by producing an array of proinflammatory cytokines including interleukin-8, tumour necrosis factor-alpha, monocyte chemotactic protein-1, granulocyte-macrophage colony-stimulating factor, extractable nuclear antigen-78 and others. The response of the intestinal epithelium to bacterial pathogens is particularly intriguing because it is literally bathed by normal bacterial flora and bacterial components/products yet remains immunologically quiescent despite this potentially hostile environment. In contrast, when challenged by bacterial pathogens, intestinal epithelial cells exhibit a vigorous immunological response. Our laboratory has, therefore, focused on the immune response of intestinal epithelial cells when confronted by a specific bacterial pathogen, enteropathogenic Escherichia coli.