DOI: 10.1615/CritRevImmunol.v23.i56.10

32 pages

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Features and Functions of gd T Lymphocytes: Focus on Chemokines and Their Receptors

Dieter Kabelitz, MD
Institute of Immunology, UK S-H Campus Kiel, Michaelisstr. 5, D-24105 Kiel, Germany

Daniela Wesch
Institute of Immunology, University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany

ABSTRACT

gd T cells are a distinct subgroup of T lymphocytes that are enriched at certain anatomical localizations, such as the small intestinal epithelia and other epithelia. gd T cells recognize microbial antigens, such as heat shock proteins (in mice) or phosphorylated bacterial metabolites (in humans), and control the integrity of epithelia. At the effector cell level, they share with the conventional gd T lymphocytes potent cytotoxic activity and the capacity to produce a variety of cytokines, including specific cytokines such as keratinocyte growth factor. Here we summarize the current knowledge on the role of chemokines and their receptors in the migration and function of gd T cells. As an example, the migration of gd T cells to the small intestine is guided by the chemokine receptor CCR9 and the local expression of the corresponding ligand CCL25 (also termed thymus-expressed chemokine, TECK). Chemokine receptor expression also correlates with the functional program of T cells. In this respect, the strong expression of the MIP-1a/MIP-1b/RANTES (CCL3/CCL4/CCL5)-receptor CCR5 correlates with a T-helper 1 phenotype of human Vg9Vd2-expressing gd T cells. The regulation of chemokine receptors, together with the pattern of local chemokine production, plays an important role in the localization of gd T cells under physiological and pathophysiological conditions, such as infection, inflammation, and tumor defense.