Gut intraepithelial lymphocytes and immunity to Coccidia.

Little is known about the physiological functions of the intra-epithelial lymphocytes (IELs) of mucosal tissues, including their role in immunity to infection. Most IELs are T cells, but their surface phenotype and activation characteristics are different from those of peripheral T cells. Here, Vincent McDonald outlines the distinctive features of IELs and presents evidence, particularly from studies of Coccidia, that these cells have an important role in the control of intracellular infection at the mucosal surface.