Watching of the Sentinels

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Science  09 Apr 2010:
Vol. 328, Issue 5975, pp. 139
DOI: 10.1126/science.328.5975.139-b

Natural killer T cells (NKTs) are a subset of unconventional T cells. They express a limited T cell receptor repertoire and recognize lipid (rather than protein) antigens presented by the nonclassical major histocompatability complex CD1d. Although NKTs have been implicated in antimicrobial, inflammatory, and autoimmune responses, their dynamics during an immune response and the antigen-presenting cell (APC) populations that mediate their activation are not well defined.

Lee et al. have visualize d the response of NKTs in the liver to infection with Borrelia burgdorferi (the causal agent of Lyme's disease), whereas Barral et al. followed NKTs in lymph nodes in response to particulate lipid antigens. In mice infected with Borrelia, they proliferated rapidly and produced cytokines; in response to antigen, NKTs slowed down and formed long-lasting contacts with their relevant APCs, which in both cases were macrophages. In the liver, sinusoid-localized Kupffer cells activated NKTs, whereas lymph node NKTs were activated by a subset of macrophages located in the subcapsular sinus.

Nat. Immunol. 11, 295; 303 (2010).

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