Clone REA326 recognizes the human C-C chemokine receptor type 10 (CCR10) antigen, a multi-pass membrane protein which is also known as G-protein–coupled receptor 2 (GPR2). CCR10 is expressed by various subsets of innate-like T cells that are programmed to localize to the skin during their developmental processes in the thymus. Circulating T cells might be imprinted by skin-associated antigen-presenting cells to express CCR10 for their recruitment to the skin during the local immune response. On the other hand, IgA antibody–producing B cells generated in mucosa-associated lymphoid tissues express CCR10 for their migration and maintenance at mucosal sites. CCR10 and its ligands chemokines CCL27 and CCL28 are uniquely involved in the epithelial immunity. CCL27 is up-regulated in inflamed skin, whereas CCL28 is selectively expressed in intestinal epithelium. In vitro
, CCL27−CCR10 interactions mediate the preferential migration of skin-homing CLA-bearing memory T cells. Increasing evidence also found that CCR10/ligands are involved in regulation of other immune cells in epithelial immunity and are frequently exploited by epithelium-localizing or -originated cancer cells for their survival, proliferation, and evasion from immune surveillance.