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Antigen‐specific recognition of bacterial antigens by NKT cells
Author(s) -
Kronenberg Mitchell,
Kinjo Yuki,
Tupin Emmanuel,
Benhnia Mohammed RafiiEl Idrissi,
Zajonc Dirk,
Sellati Timothy J
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.855.1
Subject(s) - cd1d , natural killer t cell , glycolipid , antigen , t cell receptor , biology , cd1 , t cell , microbiology and biotechnology , immunology , immune system , cd8
The objective of these studies is to understand the biochemistry and biological significance of microbial glycolipid antigen recognition by natural killer T (NKT) cells, a natural memory lymphocyte population that expresses an invariant T cell antigen receptor (TCR) alpha chain. We have identified two types of glycolipids presented by CD1d and recognized by the NKT cell TCR. Sphingomonas, which are environmental bacteria, have antigenic glycosphingolipids (GSLs), containing a ceramide lipid moiety. The second type of lipid is a glycosylated diacyl glycerol found in Borrelia burgdorferi , a spirochete that causes Lyme disease. Interestingly, mouse and human NKT cells selectively respond to diacylglycerols with different acyl chains, as mouse CD1d prefers to present compounds with shorter and less saturated fatty acids. Therefore, the recognition of these antigens is highly sensitive to the nature of the lipid, which is buried in the CD1d groove. To establish the significance of this response, we analyzed NKT cell deficient mice and controls infected with B. burgdorferi . The NKT cell deficient mice had increased joint inflammation at five weeks after infection and reduced bacterial clearance. Our data therefore strongly suggest that the NKT cells participate in host defense against bacterial pathogens through the recognition of microbial glycolipids by their invariant TCR.