Natural killer T cells recognize diacylglycerol antigens from pathogenic bacteria

Nature Immunology 7: 978-986 (2006)

Speaker: 黃千晏                             Time: 2006/11/29 14:00~15:00

Commentator: 謝奇璋 醫師                   Place: Room 601

Abstract：

Natural killer T (NKT) cells are atypical T lymphocytes that express NK cell receptors as well as an invariant T-cell receptor (TCR) α chain paired with one β chain (1). They recognize the glycolipids presented by CD1d, a class I-like antigen-presenting molecule. Previous studies have shown that the NKT cells can directly recognize the α-linked glycosphingolipids from nonpathogenic Sphingomonas spp. (2). To test whether other classes of glycolipids from the pathogenic microbes can also stimulate NKT cells, the authors infected the NKT cells with Borrelia burgdorferi, the causative agent of Lyme disease. They found that the expression of both CD25 and CD69 was increased on the Vα14 NKT cells in mice infected by B. burgdorferi. They also foundthat the α-galactosyl diacylglycerols from B. burgdorferi induced the proliferation of the NKT cells and cytokine production through direct TCR recognition, but not via Toll-like receptor (TLR) signals. They further demonstrated that the glycolipid’s antigenic potency was determined by the length and saturation of acyl chains. These findings suggest that the NKT cells can also recognize the glycolipids in a pathogenic bacterium and the immune responses driven by T cell receptor-mediated glycolipid recognition may provide protection against the pathogens.

References：

1. Godfrey, D.I. and Kronenberg, M. Going both ways: immune regulation via CD1d-dependent NKT cells. J. Clin. Invest. 114, 1379-1388 (2004).

2. Kinjo, Y. et al. Recognition of bacterial glycosphingolipids by natural killer T cells. Nature 434, 520-525 (2005).