tailieunhanh - Báo cáo y học: "Natural killer T cells and rheumatoid arthritis: friend or foe"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học General Psychiatry cung cấp cho các bạn kiến thức về ngành y đề tài:Natural killer T cells and rheumatoid arthritis: friend or foe? | Arthritis Research Therapy Vol 7 No 2 Elewaut Viewpoint Natural killer T cells and rheumatoid arthritis friend or foe Dirk Elewaut Laboratory for Molecular Immunology and Inflammation Division of Rheumatology Ghent University Hospital Belgium Corresponding author Dirk Elewaut Published 14 February 2005 Arthritis Res Ther 2005 7 88-89 DOI ar1714 2005 BioMed Central Ltd Natural Killer T NKT cells have been described as T lymphocytes expressing NK receptors such as . This lymphocyte subset consists of several subpopulations each with distinct characteristics 1 2 . Unlike conventional T cells the vast majority of mouse NKT cells recognize glycolipid antigens including a-galactosyl-ceramide a-GalCer a glycosphingolipid originally isolated from marine sponges that can not be found in mammalian cells 3 . a-GalCer is presented by an MHC class I like antigen presenting molecule CD1d. Several studies have highlighted the unique features of NKT cells because their T cell receptor TCR repertoire is highly skewed with an invariant TCR-a rearrangement Va14-Ja18. In humans a similar NKT cell subset with an invariant TCR-a chain Va24 exists. Therefore these cells are often referred to as Vai NKT cells. A characteristic feature of Vai NKT cells is their rapid production of large quantities of both Th1 and Th2 cytokines upon stimulation. These cells therefore may profoundly regulate the immune system they may either enhance or suppress immune responses 4 . Several groups have investigated whether Vai NKT cells are relevant for the pathogenesis of autoimmune diseases. There is evidence suggesting that Vai NKT cells naturally influence autoimmunity and from other experiments it appeared that a vigorous but unnatural activation of Vai NKT cells by a-GalCer is required to elicit their regulatory function. For example in type 1 diabetes Vai NKT cells are considered to be protective 5 although some conflicting reports exist 6 7 . Vai NKT cells are also .