Induced recruitment of NK cells to lymph nodes provides IFN-gamma for T(H)1 priming.
TL;DR: It is shown in mice that natural killer (NK) cells are rapidly recruited in a CCR7-independent, CXCR3-dependent manner to lymph nodes on stimulation by the injection of mature DCs, and an induced pathway of NK cell migration in antigen-stimulated lymph nodes is identified.
Abstract: Naive T cells are stimulated by antigen-presenting dendritic cells (DCs) in secondary lymphoid organs, but whether other types of cell participate in T cell priming is unclear. Here we show in mice that natural killer (NK) cells, which are normally excluded from lymph nodes, are rapidly recruited in a CCR7-independent, CXCR3-dependent manner to lymph nodes on stimulation by the injection of mature DCs. Recruitment of NK cells is also induced by some, but not all, adjuvants and correlates with the induction of T helper cell type 1 (TH1) responses. NK cell depletion and reconstitution experiments show that NK cells provide an early source of interferon-γ (IFN-γ) that is necessary for TH1 polarization. Taken together, our results identify an induced pathway of NK cell migration in antigen-stimulated lymph nodes and a mechanism by which some adjuvants may facilitate TH1 responses.
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TL;DR: Although NK cells might appear to be redundant in several conditions of immune challenge in humans, NK cell manipulation seems to hold promise in efforts to improve hematopoietic and solid organ transplantation, promote antitumor immunotherapy and control inflammatory and autoimmune disorders.
Abstract: Natural killer (NK) cells are effector lymphocytes of the innate immune system that control several types of tumors and microbial infections by limiting their spread and subsequent tissue damage. Recent research highlights the fact that NK cells are also regulatory cells engaged in reciprocal interactions with dendritic cells, macrophages, T cells and endothelial cells. NK cells can thus limit or exacerbate immune responses. Although NK cells might appear to be redundant in several conditions of immune challenge in humans, NK cell manipulation seems to hold promise in efforts to improve hematopoietic and solid organ transplantation, promote antitumor immunotherapy and control inflammatory and autoimmune disorders.
3,108 citations
TL;DR: NK cells are now recognized to express a repertoire of activating and inhibitory receptors that is calibrated to ensure self-tolerance while allowing efficacy against assaults such as viral infection and tumor development.
Abstract: Natural killer (NK) cells were originally defined as effector lymphocytes of innate immunity endowed with constitutive cytolytic functions. More recently, a more nuanced view of NK cells has emerged. NK cells are now recognized to express a repertoire of activating and inhibitory receptors that is calibrated to ensure self-tolerance while allowing efficacy against assaults such as viral infection and tumor development. Moreover, NK cells do not react in an invariant manner but rather adapt to their environment. Finally, recent studies have unveiled that NK cells can also mount a form of antigen-specific immunologic memory. NK cells thus exert sophisticated biological functions that are attributes of both innate and adaptive immunity, blurring the functional borders between these two arms of the immune response.
2,280 citations
TL;DR: This review highlights the findings that have advanced the understanding of TGF-beta in the immune system and in disease.
Abstract: Transforming growth factor-beta (TGF-beta) is a potent regulatory cytokine with diverse effects on hemopoietic cells. The pivotal function of TGF-beta in the immune system is to maintain tolerance via the regulation of lymphocyte proliferation, differentiation, and survival. In addition, TGF-beta controls the initiation and resolution of inflammatory responses through the regulation of chemotaxis, activation, and survival of lymphocytes, natural killer cells, dendritic cells, macrophages, mast cells, and granulocytes. The regulatory activity of TGF-beta is modulated by the cell differentiation state and by the presence of inflammatory cytokines and costimulatory molecules. Collectively, TGF-beta inhibits the development of immunopathology to self or nonharmful antigens without compromising immune responses to pathogens. This review highlights the findings that have advanced our understanding of TGF-beta in the immune system and in disease.
2,084 citations
TL;DR: This review focuses on recent advances in understanding how the chemokine system orchestrates immune cell migration and positioning at the organismic level in homeostasis, in acute inflammation, and during the generation and regulation of adoptive primary and secondary immune responses in the lymphoid system and peripheral nonlymphoid tissue.
Abstract: Chemokines are chemotactic cytokines that control the migratory patterns and positioning of all immune cells. Although chemokines were initially appreciated as important mediators of acute inflammation, we now know that this complex system of approximately 50 endogenous chemokine ligands and 20 G protein–coupled seven-transmembrane signaling receptors is also critical for the generation of primary and secondary adaptive cellular and humoral immune responses. Recent studies demonstrate important roles for the chemokine system in the priming of naive T cells, in cell fate decisions such as effector and memory cell differentiation, and in regulatory T cell function. In this review, we focus on recent advances in understanding how the chemokine system orchestrates immune cell migration and positioning at the organismic level in homeostasis, in acute inflammation, and during the generation and regulation of adoptive primary and secondary immune responses in the lymphoid system and peripheral nonlymphoid tissue.
1,475 citations
Cites background from "Induced recruitment of NK cells to ..."
...Additionally, CXCR3 recruits pDCs, and these cells have been shown to augment Th1 responses by cytokine production (157, 158)....
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TL;DR: It is shown that mTOR (mammalian target of rapamycin, also known as FRAP1) is a major regulator of memory CD8 T-cell differentiation, and in contrast to what was expected, the immunosuppressive drug Rapamycin has immunostimulatory effects on the generation of memoryCD8 T cells.
Abstract: Memory CD8 T cells are a critical component of protective immunity, and inducing effective memory T-cell responses is a major goal of vaccines against chronic infections and tumours. Considerable effort has gone into designing vaccine regimens that will increase the magnitude of the memory response, but there has been minimal emphasis on developing strategies to improve the functional qualities of memory T cells. Here we show that mTOR (mammalian target of rapamycin, also known as FRAP1) is a major regulator of memory CD8 T-cell differentiation, and in contrast to what we expected, the immunosuppressive drug rapamycin has immunostimulatory effects on the generation of memory CD8 T cells. Treatment of mice with rapamycin following acute lymphocytic choriomeningitis virus infection enhanced not only the quantity but also the quality of virus-specific CD8 T cells. Similar effects were seen after immunization of mice with a vaccine based on non-replicating virus-like particles. In addition, rapamycin treatment also enhanced memory T-cell responses in non-human primates following vaccination with modified vaccinia virus Ankara. Rapamycin was effective during both the expansion and contraction phases of the T-cell response; during the expansion phase it increased the number of memory precursors, and during the contraction phase (effector to memory transition) it accelerated the memory T-cell differentiation program. Experiments using RNA interference to inhibit expression of mTOR, raptor (also known as 4932417H02Rik) or FKBP12 (also known as FKBP1A) in antigen-specific CD8 T cells showed that mTOR acts intrinsically through the mTORC1 (mTOR complex 1) pathway to regulate memory T-cell differentiation. Thus these studies identify a molecular pathway regulating memory formation and provide an effective strategy for improving the functional qualities of vaccine- or infection-induced memory T cells.
1,384 citations
References
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TL;DR: Once a neglected cell type, dendritic cells can now be readily obtained in sufficient quantities to allow molecular and cell biological analysis and the realization that these cells are a powerful tool for manipulating the immune system is realized.
Abstract: B and T lymphocytes are the mediators of immunity, but their function is under the control of dendritic cells. Dendritic cells in the periphery capture and process antigens, express lymphocyte co-stimulatory molecules, migrate to lymphoid organs and secrete cytokines to initiate immune responses. They not only activate lymphocytes, they also tolerize T cells to antigens that are innate to the body (self-antigens), thereby minimizing autoimmune reactions. Once a neglected cell type, dendritic cells can now be readily obtained in sufficient quantities to allow molecular and cell biological analysis. With knowledge comes the realization that these cells are a powerful tool for manipulating the immune system.
14,532 citations
"Induced recruitment of NK cells to ..." refers background in this paper
...dtd" [ ]> Antigens delivered as vaccines in the skin are captured by local DCs and transported to draining lymph nodes for presentation to naive T cells and the induction of immune response...
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TL;DR: The understanding of the relative roles of IL-12 and other factors in TH1-type maturation of both CD4+ and CD8+ T cells is discussed here, including the participation in this process ofIL-23 and IL-27, two recently discovered members of the new family of heterodimeric cytokines.
Abstract: Interleukin-12 (IL-12) is a heterodimeric pro-inflammatory cytokine that induces the production of interferon-gamma (IFN-gamma), favours the differentiation of T helper 1 (T(H)1) cells and forms a link between innate resistance and adaptive immunity. Dendritic cells (DCs) and phagocytes produce IL-12 in response to pathogens during infection. Production of IL-12 is dependent on differential mechanisms of regulation of expression of the genes encoding IL-12, patterns of Toll-like receptor (TLR) expression and cross-regulation between the different DC subsets, involving cytokines such as IL-10 and type I IFN. Recent data, however, argue against an absolute requirement for IL-12 for T(H)1 responses. Our understanding of the relative roles of IL-12 and other factors in T(H)1-type maturation of both CD4+ and CD8+ T cells is discussed here, including the participation in this process of IL-23 and IL-27, two recently discovered members of the new family of heterodimeric cytokines.
3,591 citations
"Induced recruitment of NK cells to ..." refers methods in this paper
...This work was supported by grants from the Swiss National Science Foundation (31-63885) and from the European Commission (‘Memovax’ QLK2-CT-2001-01205 and ‘Main’ FP6-502935)....
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TL;DR: This method allows by simple means the generation of high numbers of murine DC with very low B cell or granulocyte contaminations, which will be valuable to study DC biology notably at the molecular level.
2,935 citations
"Induced recruitment of NK cells to ..." refers methods in this paper
...This work was supported by grants from the Swiss National Science Foundation (31-63885) and from the European Commission (‘Memovax’ QLK2-CT-2001-01205 and ‘Main’ FP6-502935)....
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TL;DR: This review addresses the heterogeneity of TCM and TEM, their differentiation stages, and the current models for their generation and maintenance in humans and mice.
Abstract: The memory T cell pool functions as a dynamic repository of antigen-experienced T lymphocytes that accumulate over the lifetime of the individual. Recent studies indicate that memory T lymphocytes contain distinct populations of central memory (TCM) and effector memory (TEM) cells characterized by distinct homing capacity and effector function. This review addresses the heterogeneity of TCM and TEM, their differentiation stages, and the current models for their generation and maintenance in humans and mice.
2,881 citations
"Induced recruitment of NK cells to ..." refers background in this paper
...In addition to naive T cells, central memory T cells migrate to lymph nodes via CCR7, whereas CCR7 − effector memory T cells are largely excluded from lymph node...
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TL;DR: In this paper, the chemokine receptor CCR7 was identified as an important organizer of the primary immune response in mice, and severely delayed kinetics regarding the antibody response and lack contact sensitivity and delayed type hypersensitivity reactions.
2,388 citations