NKT cells represent an innate-like lymphocyte lineage regulating disease conditions such as infection, cancer, autoimmunity and asthma through the secretion of Th1 and Th2 cytokines and chemokines. They use a semi-invariant ab TCR to recognize lipids presented by CD1d on dendritic cells, but these ligands have long remained elusive. This project investigates the nature of lipid antigens, their mode of recognition and their function in vivo. In the past funding period, we identified two conserved but structurally different NKT ligands involved in different types of anti-microbial responses. The self glycosphingolipid (GSL) iGb3 directs the developmental expansion of NKT cells and their responses against LPS-expressing bacteria, whereas aglycuronylceramides trigger responses against Gram-negative LPS-negative bacteria that would otherwise largely escape TLR detection. We will now study how immune responses triggered by these NKT ligands are integrated in the context of other microbial signals and we will use synthetic variants of these ligands to understand the basis of their cellular and subcellular targeting for antigen presentation.
The specific aims are 1) Endogenous NKT ligands: their recognition and regulation in the context of autoreactive responses, particularly infectious conditions 2) Microbial NKT ligands: their recognition and interplay with Toll like receptor responses and 3) Cell biology of synthetic NKT ligands: new fluorescent lipids will be developed to address elusive questions about lipid uptake and trafficking in different cell types for antigen presentation. The project is part of a larger multidisciplinary Program Project exploring chemical, structural and functional aspects of lipid antigens during immune responses The public health implications of these studies reside in the importance of NKT cells in regulating world wide diseases such as infections by Rickettsiales, asthma, cancer and autoimmunity and in the prospects of harnessing the biological properties of their ligands for the development of new vaccine adjubants.
|Tefit, Josianne Nitcheu; CrabÃ©, Sandrine; Orlandini, Bernard et al. (2014) Efficacy of ABX196, a new NKT agonist, in prophylactic human vaccination. Vaccine 32:6138-45|
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|Kain, Lisa; Webb, Bill; Anderson, Brian L et al. (2014) The identification of the endogenous ligands of natural killer T cells reveals the presence of mammalian Î±-linked glycosylceramides. Immunity 41:543-54|
|Anderson, Brian L; Teyton, Luc; Bendelac, Albert et al. (2013) Stimulation of natural killer T cells by glycolipids. Molecules 18:15662-88|
|Luoma, Adrienne M; Castro, Caitlin D; Mayassi, Toufic et al. (2013) Crystal structure of VÎ´1 T cell receptor in complex with CD1d-sulfatide shows MHC-like recognition of a self-lipid by human Î³Î´ T cells. Immunity 39:1032-42|
|Freigang, Stefan; Kain, Lisa; Teyton, Luc (2013) Transport and uptake of immunogenic lipids. Mol Immunol 55:179-81|
|Constantinides, Michael G; Bendelac, Albert (2013) Transcriptional regulation of the NKT cell lineage. Curr Opin Immunol 25:161-7|
|Bai, Li; Deng, Shenglou; Reboulet, Rachel et al. (2013) Natural killer T (NKT)-B-cell interactions promote prolonged antibody responses and long-term memory to pneumococcal capsular polysaccharides. Proc Natl Acad Sci U S A 110:16097-102|
|Seiler, Michael P; Mathew, Rebecca; Liszewski, Megan K et al. (2012) Elevated and sustained expression of the transcription factors Egr1 and Egr2 controls NKT lineage differentiation in response to TCR signaling. Nat Immunol 13:264-71|
|Bai, Li; Constantinides, Michael G; Thomas, Seddon Y et al. (2012) Distinct APCs explain the cytokine bias of Î±-galactosylceramide variants in vivo. J Immunol 188:3053-61|
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