scholarly journals Functionally distinct NKT cell subsets and subtypes

2005 ◽  
Vol 202 (12) ◽  
pp. 1623-1626 ◽  
Author(s):  
Ken-ichiro Seino ◽  
Masaru Taniguchi

Natural killer T (NKT) cells are a population of autoreactive cells that mediate both protective and regulatory immune functions. NKT cells comprise several subsets of cells, but it has been unclear whether these different NKT cell subsets possess distinct functions in vivo. New studies now demonstrate that subsets of NKT cells are indeed functionally distinct and that the specific functions of these cells may be dictated in part by organ-specific mechanisms.

1999 ◽  
Vol 189 (7) ◽  
pp. 1121-1128 ◽  
Author(s):  
Hidemitsu Kitamura ◽  
Kenji Iwakabe ◽  
Takashi Yahata ◽  
Shin-ichiro Nishimura ◽  
Akio Ohta ◽  
...  

The natural killer T (NKT) cell ligand α-galactosylceramide (α-GalCer) exhibits profound antitumor activities in vivo that resemble interleukin (IL)-12–mediated antitumor activities. Because of these similarities between the activities of α-GalCer and IL-12, we investigated the involvement of IL-12 in the activation of NKT cells by α-GalCer. We first established, using purified subsets of various lymphocyte populations, that α-GalCer selectively activates NKT cells for production of interferon (IFN)-γ. Production of IFN-γ by NKT cells in response to α-GalCer required IL-12 produced by dendritic cells (DCs) and direct contact between NKT cells and DCs through CD40/CD40 ligand interactions. Moreover, α-GalCer strongly induced the expression of IL-12 receptor on NKT cells from wild-type but not CD1−/− or Vα14−/− mice. This effect of α-GalCer required the production of IFN-γ by NKT cells and production of IL-12 by DCs. Finally, we showed that treatment of mice with suboptimal doses of α-GalCer together with suboptimal doses of IL-12 resulted in strongly enhanced natural killing activity and IFN-γ production. Collectively, these findings indicate an important role for DC-produced IL-12 in the activation of NKT cells by α-GalCer and suggest that NKT cells may be able to condition DCs for subsequent immune responses. Our results also suggest a novel approach for immunotherapy of cancer.


2002 ◽  
Vol 195 (7) ◽  
pp. 835-844 ◽  
Author(s):  
Daniel G. Pellicci ◽  
Kirsten J.L. Hammond ◽  
Adam P. Uldrich ◽  
Alan G. Baxter ◽  
Mark J. Smyth ◽  
...  

The development of CD1d-dependent natural killer T (NKT) cells is poorly understood. We have used both CD1d/α-galactosylceramide (CD1d/αGC) tetramers and anti-NK1.1 to investigate NKT cell development in vitro and in vivo. Confirming the thymus-dependence of these cells, we show that CD1d/αGC tetramer-binding NKT cells, including NK1.1+ and NK1.1− subsets, develop in fetal thymus organ culture (FTOC) and are completely absent in nude mice. Ontogenically, CD1d/αGC tetramer-binding NKT cells first appear in the thymus, at day 5 after birth, as CD4+CD8−NK1.1−cells. NK1.1+ NKT cells, including CD4+ and CD4−CD8− subsets, appeared at days 7–8 but remained a minor subset until at least 3 wk of age. Using intrathymic transfer experiments, CD4+NK1.1− NKT cells gave rise to NK1.1+ NKT cells (including CD4+ and CD4− subsets), but not vice-versa. This maturation step was not required for NKT cells to migrate to other tissues, as NK1.1− NKT cells were detected in liver and spleen as early as day 8 after birth, and the majority of NKT cells among recent thymic emigrants (RTE) were NK1.1−. Further elucidation of this NKT cell developmental pathway should prove to be invaluable for studying the mechanisms that regulate the development of these cells.


2003 ◽  
Vol 198 (1) ◽  
pp. 173-181 ◽  
Author(s):  
Dianna Y. Wu ◽  
Neil H. Segal ◽  
Stephane Sidobre ◽  
Mitchell Kronenberg ◽  
Paul B. Chapman

GD3, a ganglioside expressed on human melanoma, can be recognized by the humoral immune system. In this paper, we demonstrate that immunizing mice with the human melanoma cell line SK-MEL-28 (GD3+ GM2− CD1−) or with syngeneic APCs loaded with GD3 can induce a GD3-reactive natural killer T (NKT) cell response. GD3-reactive NKT cells were detected among splenocytes of immunized mice at frequencies of ∼1:2,000 both by ELISPOT and GD3-loaded mouse CD1d tetramer analysis. GD3-reactive NKT cells did not react with GM2, a closely related ganglioside, and were not detectable in unimmunized mice. GD3-reactive NKT cells initially produced IL-4 and IFN-γ followed by IL-10. They were CD1d restricted in that reactivity was abrogated when APCs were blocked with anti-CD1d monoclonal antibody before being loaded with GD3 or when APCs from CD1d knockout mice were used. Because SK-MEL-28 does not express any isoform of human CD1, GD3 must be cross-presented by murine APCs in vivo. This is the first analysis of a natural ligand for mouse NKT cells and the first definitive paper of cross-presentation to NKT cells. This could be a mechanism for NKT cell recognition of tumor gangliosides in CD1− tumors.


2006 ◽  
Vol 203 (5) ◽  
pp. 1197-1207 ◽  
Author(s):  
Datsen G. Wei ◽  
Shane A. Curran ◽  
Paul B. Savage ◽  
Luc Teyton ◽  
Albert Bendelac

Mouse and human natural killer T (NKT) cells recognize a restricted set of glycosphingolipids presented by CD1d molecules, including self iGb3 and microbial α-glycuronosylceramides. The importance of the canonical Vα14-Jα18 TCR α chain for antigen recognition by NKT cells is well recognized, but the mechanisms underlying the Vβ8, Vβ7, and Vβ2 bias in mouse have not been explored. To study the influences of thymic selection and the constraints of pairing with Vα14-Jα18, we have created a population of mature T cells expressing Vα14-Jα18 TCR α chain in CD1d-deficient mice and studied its recognition properties in vitro and in vivo. Transgenic cells expressed a diverse Vβ repertoire but their recognition of endogenous ligands and synthetic iGb3 was restricted to the same biased Vβ repertoire as expressed in natural NKT cells. In contrast, α-GalCer, a synthetic homologue of microbial α-glycuronosylceramides, was recognized by a broader set of Vβ chains, including the biased NKT set but also Vβ6, Vβ9, Vβ10, and Vβ14. These surprising findings demonstrate that, whereas Vβ8, Vβ7, and Vβ2 represent the optimal solution for recognition of endogenous ligand, many Vβ chains that are potentially useful for the recognition of foreign lipids fail to be selected in the NKT cell repertoire.


2006 ◽  
Vol 203 (10) ◽  
pp. 2229-2232 ◽  
Author(s):  
Dale I. Godfrey ◽  
Malcolm J. McConville ◽  
Daniel G. Pellicci

Natural killer T cells (NKT cells) are selected in the thymus by self-glycolipid antigens presented by CD1d molecules. It is currently thought that one specific component of the lysosomal processing pathway, which leads to the production of isoglobotrihexosylceramide (iGb3), is essential for normal NKT cell development. New evidence now shows that NKT cell development can be disrupted by a diverse range of mutations that interfere with different elements of the lysosomal processing and degradation of glycolipids. This suggests that lysosomal storage diseases (LSDs) in general, rather than one specific defect, can disrupt CD1d antigen presentation, leading to impaired development of NKT cells.


1999 ◽  
Vol 190 (9) ◽  
pp. 1215-1226 ◽  
Author(s):  
Koh-Hei Sonoda ◽  
Mark Exley ◽  
Scott Snapper ◽  
Steven P. Balk ◽  
Joan Stein-Streilein

Systemic tolerance can be elicited by introducing antigen into an immune-privileged site, such as the eye, or directly into the blood. Both routes of immunization result in a selective deficiency of systemic delayed type hypersensitivity. Although the experimental animal model of anterior chamber–associated immune deviation (ACAID) occurs in most mouse strains, ACAID cannot be induced in several mutant mouse strains that are coincidentally deficient in natural killer T (NKT) cells. Therefore, this model for immune-privileged site–mediated tolerance provided us with an excellent format for studying the role of NKT cells in the development of tolerance. The following data show that CD1-reactive NKT cells are required for the development of systemic tolerance induced via the eye as follows: (a) CD1 knockout mice were unable to develop ACAID unless they were reconstituted with NKT cells together with CD1+ antigen-presenting cells; (b) specific antibody depletion of NKT cells in vivo abrogated the development of ACAID; and (c) anti-CD1 monoclonal antibody treatment of wild-type mice prevented ACAID development. Significantly, CD1-reactive NKT cells were not required for intravenously induced systemic tolerance, thereby establishing that different mechanisms mediate development of tolerance to antigens inoculated by these routes. A critical role for NKT cells in the development of systemic tolerance associated with an immune-privileged site suggests a mechanism involving NKT cells in self-tolerance and their defects in autoimmunity.


2006 ◽  
Vol 84 (1) ◽  
pp. 67-75 ◽  
Author(s):  
Stewart C. Whitman ◽  
Tanya A. Ramsamy

Atherosclerosis is a multifactor, highly complex disease with numerous aetiologies that work synergistically to promote lesion development. One of the emerging components that drive the development of both early- and late-stage atherosclerotic lesions is the participation of both the innate and acquired immune systems. In both humans and animal models of atherosclerosis, the most prominent cells that infiltrate evolving lesions are macrophages and T lymphocytes. The functional loss of either of these cell types reduces the extent of atherosclerosis in mice that were rendered susceptible to the disease by deficiency of either apolipoprotein E or the LDL (low density lipoprotein) receptor. In addition to these major immune cell participants, a number of less prominent leukocyte populations that can modulate the atherogenic process are also involved. This review will focus on the participatory role of two “less prominent” immune components, namely natural killer (NK) cells and natural killer T (NKT) cells. Although this review will highlight the fact that both NK and NKT cells are not sufficient for causing the disease, the roles played by both these cells types are becoming increasingly important in understanding the complexity of this disease process.


Blood ◽  
2008 ◽  
Vol 112 (10) ◽  
pp. 4128-4138 ◽  
Author(s):  
Xiaohua Wang ◽  
Xiuxu Chen ◽  
Lance Rodenkirch ◽  
William Simonson ◽  
Sarah Wernimont ◽  
...  

Abstract Natural killer T (NKT) cells are innate-like T cells that recognize specific microbial antigens and also display autoreactivity to self-antigens. The nature of NKT-cell autoreactive activation remains poorly understood. We show here that the mitogen-activated protein kinase (MAPK) pathway is operative during human NKT-cell autoreactive activation, but calcium signaling is severely impaired. This results in a response that is biased toward granulocyte macrophage colony-stimulating factor (GM-CSF) secretion because this cytokine requires extracellular signal-regulated kinase (ERK) signaling but is not highly calcium dependent, whereas interferon-γ (IFN-γ), interleukin (IL)–4, and IL-2 production are minimal. Autoreactive activation was associated with reduced migration velocity but did not induce arrest; thus, NKT cells retained the ability to survey antigen presenting cells (APCs). IL-12 and IL-18 stimulated autoreactively activated NKT cells to secrete IFN-γ, and this was mediated by Janus kinase-signal transducers and activators of transcription (JAK-STAT)–dependent signaling without induction of calcium flux. This pathway did not require concurrent contact with CD1d+ APCs but was strictly dependent on preceding autoreactive stimulation that induced ERK activation. In contrast, NKT-cell responses to the glycolipid antigen α-galactosyl ceramide (α-GalCer) were dampened by prior autoreactive activation. These results show that NKT-cell autoreactivity induces restricted cytokine secretion and leads to altered basal activation that potentiates innate responsiveness to costimulatory cytokines while modulating sensitivity to foreign antigens.


Blood ◽  
2006 ◽  
Vol 108 (2) ◽  
pp. 618-621 ◽  
Author(s):  
David H. Chang ◽  
Nancy Liu ◽  
Virginia Klimek ◽  
Hani Hassoun ◽  
Amitabha Mazumder ◽  
...  

Natural killer T (NKT) cells are CD1d-restricted glycolipid reactive innate lymphocytes that play an important role in protection from pathogens and tumors. Pharmacologic approaches to enhance NKT cell function will facilitate specific NKT targeting in the clinic. Here we show that lenalidomide (LEN), a novel thalidomide (Thal) analog, enhances antigen-specific expansion of NKT cells in response to the NKT ligand α-galactosylceramide (α-GalCer) in both healthy donors and patients with myeloma. NKT cells activated in the presence of LEN have greater ability to secrete interferon-γ. Antigen-dependent activation of NKT cells was greater in the presence of dexamethasone (DEX) plus LEN than with DEX alone. Therapy with LEN/Thal also led to an increase in NKT cells in vivo in patients with myeloma and del5q myelodysplastic syndrome. Together these data demonstrate that LEN and its analogues enhance CD1d-mediated presentation of glycolipid antigens and support combining these agents with NKT targeted approaches for protection against tumors.


2000 ◽  
Vol 192 (11) ◽  
pp. 1645-1652 ◽  
Author(s):  
Francesco Dieli ◽  
Guido Sireci ◽  
Domenica Russo ◽  
Masaru Taniguchi ◽  
Juraj Ivanyi ◽  
...  

The generalized Shwartzman reaction in mice which had been primed and challenged with lipopolysaccharide (LPS) depends on interleukin (IL)-12–induced interferon (IFN)-γ production at the priming stage. We examined the involvement in the priming mechanism of the unique population of Vα14 natural killer T (NKT) cells because they promptly produce IFN-γ after IL-12 stimulation. We report here that LPS- or IL-12–primed NKT cell genetically deficient mice were found to be resistant to LPS-elicited mortality. This outcome can be attributed to the reduction of IFN-γ production, because injection of recombinant mouse IFN-γ, but not injection of IL-12, effectively primed the NKT cell–deficient mice. However, priming with high doses of LPS caused mortality of severe combined immunodeficiency, NKT cell–deficient, and CD1-deficient mice, indicating a major contribution of NKT cells to the Shwartzman reaction elicited by low doses of LPS, whereas at higher doses of LPS NK cells play a prominent role. These results suggest that the numerically small NKT cell population of normal mice apparently plays a mandatory role in the priming stage of the generalized Shwartzman reaction.


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