Repeated injection of alpha-galactosylceramide, an agonistic ligand for natural killer T (NKT) cells, results in long-term unresponsiveness or anergy, which severely limits its clinical application. However, the molecular mechanisms leading to NKT anergy induction remain unclear. We show here that the decreased IFN-gamma production and failed tumor rejection observed in anergized NKT cells are ...

Human natural killer (NK) T cells are unique T lymphocytes that express an invariant T cell receptor (TCR) Valpha24-Vbeta11 and have been implicated to play a role in various diseases. A subset of NKT cells express CD4 and hence are potential targets for human immunodeficiency virus (HIV)-1 infection. We demonstrate that both resting and activated human Valpha24(+) T cells express high levels o...

NKT cells are key regulators of autoimmunity, tumor immune surveillance, and the immune response to pathogens. The role of NKT cells in regulating adaptive immunity to cutaneous Ags is largely unknown. This study explores the role of CD1d-restricted NKT cells in cross-priming of CD8 effector T cells to OVA expressed in epithelial keratinocytes (K5mOVA transgenic mouse). In a skin grafting model...

BACKGROUND Dendritic cells (DC) can act tolerogenic at a semi-mature stage by induction of protective CD4(+) T cell and NKT cell responses. METHODOLOGY/PRINCIPAL FINDINGS Here we studied the role of the co-inhibitory molecule B7-H1 (PD-L1, CD274) on semi-mature DC that were generated from bone marrow (BM) cells of B7-H1(-/-) mice and applied to the model of Experimental Autoimmune Encephalomy...

Natural killer T (NKT) cells represent a unique T cell lineage. The NKT cells bearing an invariant TCR (iNKT cells) recognize a small variety of glycolipid antigens in the context of CD1d (non-classical MHC-I) presentation. CD1d-restricted iNKT cells play a regulatory role during an immune response by producing cytokines (IFN-gamma, and IL-4). The identification of alpha-galactosyl-ceramide (al...

NK1.1+ T (NKT) cells are efficient regulators of early host responses which have been shown to play a role in tumor surveillance. The relevance of NKT cells in immune surveillance of viral infections, however, is not well understood. In this study, we investigated the functional relevance of NKT cells in controlling herpesvirus infections by using challenge with murine cytomegalovirus (MCMV) as...

CD1d-restricted NKT cells play important regulatory roles in various immune responses and are rapidly and selectively depleted upon infection with HIV-1. The cause of this selective depletion is incompletely understood, although it is in part due to the high susceptibility of CD4+ NKT cells to direct infection and subsequent cell death by HIV-1. Here, we demonstrate that highly active antiretro...

Chronic inflammation including B-cell activation is commonly observed in both inherited (Gaucher disease [GD]) and acquired disorders of lipid metabolism. However, the cellular mechanisms underlying B-cell activation in these settings remain to be elucidated. Here, we report that β-glucosylceramide 22:0 (βGL1-22) and glucosylsphingosine (LGL1), 2 major sphingolipids accumulated in GD, can be re...

Natural killer T (NKT) lymphocytes are implicated in the early response to microbial infection. Further, sulfatide, a myelin self-glycosphingolipid, activates a type II NKT cell subset and can modulate disease in murine models. We examined the role of NKT cells and the effect of sulfatide treatment in a murine model of Staphylococcus aureus sepsis. The lack of CD1d-restricted NKT cells did not ...

CD1d-restricted NKT cells can be divided into two groups: type I NKT cells use a semi-invariant TCR, whereas type II express a relatively diverse set of TCRs. A major subset of type II NKT cells recognizes myelin-derived sulfatides and is selectively enriched in the CNS tissue during experimental autoimmune encephalomyelitis (EAE). We have shown that activation of sulfatide-reactive type II NKT...