The anti-tumor response of human invariant NKT (NKT) cells is well established. A novel T cell subset, mucosal-associated invariant T (MAIT) cells, possesses similar regulatory properties to NKT cells in autoimmune models and disease. Here, we examined the clonality of four T cell subsets expressing invariant aTCR, including Va7.2-Ja33 of MAIT cells, in 19 kidney and brain tumors. The MAIT clon...

Although invariant natural killer T (iNKT) cells influence antitumor responses indirectly by secreting cytokines and promoting the cytolytic functions of T and NK cells, we find that iNKT cells mediate direct tumoricidal activity in vitro and significantly inhibit tumor growth in vivo, even in the absence of other cytotoxic lymphocytes.

Little is known regarding the basis for selection of the semi-invariant alphabeta T cell receptor (TCR) expressed by natural killer T (NKT) cells or how this mediates recognition of CD1d-glycolipid complexes. We have determined the structures of two human NKT TCRs that differ in their CDR3beta composition and length. Both TCRs contain a conserved, positively charged pocket at the ligand interfa...

background and aims: natural killer t (nkt) cells have been suggested to play critical roles in a wide range of immune responses especially against hepatotropic pathogens such as hepatitis c virus (hcv). in  the  present  study,  we  investigated  the  status  of  nkt  cells  by producing interleukin-17 cytokine in  peripheral  blood.  patients and methods: as case-control study, 15 patients wi...

The Tec family tyrosine kinase, Itk, regulates signaling downstream of the TCR. The absence of Itk in CD4(+) T cells results in impaired Th2 responses along with defects in maturation, cytokine production, and survival of iNKT cells. Paradoxically, Itk(-/-) mice have spontaneously elevated serum IgE levels, resulting from an expansion of the Vγ1.1(+)Vδ6.3(+) subset of γδ T cells, known as γδ NK...

CD1 molecules belong to non-polymorphic MHC class I-like proteins and present lipid antigens to T cells. Five different CD1 genes (CD1a-e) have been identified and classified into two groups. Group 1 include CD1a-c and present pathogenic lipid antigens to αβ T cells reminiscence of peptide antigen presentation by MHC-I molecules. CD1d is the only member of Group 2 and presents foreign and self ...

Background and aims: Natural killer T (NKT) cells represent a subset of immune cells that share characteristics of the innate and adaptive immunity. Invariant NKT cells recognize glycolipid antigens such as α galactosylceramide (αGalCer) presented by the non classical MHC molecule CD1d. Decreased NKT cell frequencies have been reported in chronically HCV infected patients, however, contradictin...

Human Va24 NKT cells bearing an invariant Va24JaQ antigen receptor, the counterpart of the murine Va14 NKT cells, are activated by the specific ligand, a-galactosylceramide (a-GalCer) in a CD1d-dependent manner. Here, we demonstrate that the a-GalCer-activated Va24 NKT cells exert a potent perforin-dependent cytotoxic activity against a wide variety of human tumor cell lines. In addition, we de...

Mouse natural killer T (NKT) cells with an invariant V alpha14-J alpha18 rearrangement (V alpha14 invariant [V alpha14i] NKT cells) are either CD4(+)CD8(-) or CD4(-)CD8(-). Because transgenic mice with forced CD8 expression in all T cells exhibited a profound NKT cell deficit, the absence of CD8 has been attributed to negative selection. We now present evidence that CD8 does not serve as a core...