Inflammation occurs as a result of exposure of tissues and organs to harmful stimuli such as microbial pathogens, irritants, or toxic cellular components. The primary physical manifestations of inflammation are redness, swelling, heat, pain, and loss of function to the affected area. These processes involve the major cells of the immune system, including monocytes, macrophages, neutrophils, basophils, dendritic cells, mast cells, T-cells, and B-cells. However, examination of a range of inflammatory lesions demonstrates the presence of specific leukocytes in any given lesion. That is, the inflammatory process is regulated in such a way as to ensure that the appropriate leukocytes are recruited. These events are in turn controlled by a host of extracellular molecular regulators, including members of the cytokine and chemokine families that mediate both immune cell recruitment and complex intracellular signalling control mechanisms that characterise inflammation. This review will focus on the role of the main cytokines, chemokines, and their receptors in the pathophysiology of auto-inflammatory disorders, pro-inflammatory disorders, and neurological disorders involving inflammation.

The production of cytokines such as interferon-γ and interleukin 17 by αβ and γδ T cells influences the outcome of immune responses. Here we show that most γδ T lymphocytes expressed the tumor necrosis factor receptor family member CD27 and secreted interferon-γ, whereas interleukin 17 production was restricted to CD27- γδ T cells. In contrast to the apparent plasticity of αβ T cells, the cytokine profiles of these distinct γδ T cell subsets were essentially stable, even during infection. These phenotypes were established during thymic development, when CD27 functions as a regulator of the differentiation of γδ T cells at least in part by inducing expression of the lymphotoxin-β receptor and genes associated with trans-conditioning and interferon-γ production. Thus, the cytokine profiles of peripheral γδ T cells are predetermined mainly by a mechanism involving CD27.

The mouse CD8α + DC subset excels at cross-presentation of antigen, which can elicit robust CTL responses. A receptor allowing specific antigen targeting to this subset and its equivalent in humans would therefore be useful for the induction of antitumor CTLs. Here, we have characterized a C-type lectin of the NK cell receptor group that we named DC, NK lectin group receptor-1 (DNGR-1). DNGR-1 was found to be expressed in mice at high levels by CD8 + DCs and at low levels by plasmacytoid DCs but not by other hematopoietic cells. Human DNGR-1 was also restricted in expression to a small subset of blood DCs that bear similarities to mouse CD8α + DCs. The selective expression pattern and observed endocytic activity of DNGR-1 suggested that it could be used for antigen targeting to DCs. Consistent with this notion, antigen epitopes covalently coupled to an antibody specific for mouse DNGR-1 were selectively cross-presented by CD8α + DCs in vivo and, when given with adjuvants, induced potent CTL responses. When the antigens corresponded to tumor-expressed peptides, treatment with the antibody conjugate and adjuvant could prevent development or mediate eradication of B16 melanoma lung pseudometastases. We conclude that DNGR-1 is a novel, highly specific marker of mouse and human DC subsets that can be exploited for CTL cross-priming and tumor therapy.

Statement LF and DAvH analysed UK GWAS data, selected SNPs and designed assays for golden gate genotyping. Substantial contributions to sample collections were made by DAvH, LD, GKTH, PH, JRFW, DSS (UK2 cases); DPS, WLMcA (1958 cohort controls); CJM, WV, MLM (DUTCH samples); VT, FMS, COM, NPK, DK (IRISH samples). UKGWAS genotyping was performed as described in PD lab2. KAH extracted UKGWAS and UK2 celiac DNA samples and performed UK2 sample golden gate genotyping. GrahamT and AWR prepared Irish DNA samples. GrahamT, AWR and KAH performed Irish sample golden gate genotyping. UK2 and IRISH genotyping was performed in CAM lab, DP performed quality control steps. AZ prepared DUTCH celiac and control DNA samples, and AZ and JR performed DUTCH sample golden gate genotyping in CW lab. DVH and KAH performed final golden gate genotype clustering on all samples, with assistance from RG. LD and DAvH collected Paxgene RNA celiac blood samples, GH extracted Paxgene RNA, GH and MB performed expression chips in CW lab, GH and LF analysed expression data. GosiaT performed IL18RAP re-sequencing. MCW processed intestinal biopsies, MB and MCW performed expression chips in CW lab, MCW and GH analysed expression data. DJP performed analysis of genes in intestinal T cell subsets. KAH and GH performed bioinformatics and annotation of celiac risk variant regions DAvH, RMM, CW were Principal Investigators and directed respectively the UK, IRISH and DUTCH sample collections and with RJP designed overall strategy and obtained funding for the study. DAvH directed the entire study, performed statistical analysis and generated the figures. DAvH and CW wrote the paper. RMcG, FT and WMMcL performed additional statistical analysis. To identify additional celiac disease susceptibility genes, we recently tested 310,605 SNPs in a genome wide association study of 778 celiac cases and 1,422 population controls from the United Kingdom (UKGWAS), using the Illumina HumanHap300 BeadChip2. The only SNP outside the HLA region demonstrating genome-wide significance was rs13119723 on 4q27, located in a ∼500 kb block of linkage disequilibrium (LD) containing the IL2 and IL21 genes2. Independent replication of SNPs from the IL2-IL21 region was established in both Dutch and Irish collections of celiac patients and controls. We estimate, using the current markers, that the IL2-IL21 region explains less than 1% of the increased familial risk to celiac disease, suggesting that there are additional unidentified susceptibility genes. Since we observed a greater number of significantly associated SNPs in the UKGWAS than would be expected by chance, we proceeded to study >1,000 of the most significant UKGWAS association results in a further 1,643 celiac cases and 3,406 controls from three independent European celiac disease collections. This two-stage strategy, involving a joint analysis of all data, substantially reduces the genotyping requirements versus performing whole genome genotyping on all samples and has been shown to maintain sufficient statistical power3. ...

IntroductionDendritic cells (DCs) are thought to exert a pivotal role in the induction of antigen-specific immune responses. 1 Recent studies have demonstrated that the functional diversity of DCs can be attributed in part to the existence of distinct subsets of this important class of antigen-presenting cells. 2 Murine DCs have been classified into 3 major subsets (CD8␣ ϩ CD4 Ϫ , CD8␣ Ϫ CD4 ϩ , and CD8␣ Ϫ CD4 Ϫ ) based on their expression of the surface markers CD4 and CD8␣. It was originally thought that these cells represent distinct ontogenetic lineages with CD8␣ ϩ DCs deriving from "lymphoid" progenitors and CD4 ϩ and double-negative (DN) cells arising from a distinct set of "myeloid" precursors. 3 This concept of dual lineages for DC development has recently been overturned by a series of reports demonstrating that all 3 subsets can be generated from either common myeloid or common lymphoid progenitors. 4,5 It has also been suggested that different DC subsets represent no more than stages of DC differentiation rather than distinct lineages. 6 At present, the nature of the factors that regulate murine DC subset differentiation are poorly understood and their delineation remains an important area of investigation in DC biology.A major issue raised by the existence of distinct populations of DCs concerns whether these subsets possess distinct immunologic functions or whether their function is determined largely by environmental cues. 7 CD8␣ ϩ DCs are thought to be closely associated with the induction of cell-mediated immunity. Thus, cells belonging to this subset preferentially produce the cytokine interleukin 12 (IL-12) on stimulation with a number of microbial agents such as bacterial lipopolysaccharide (LPS), 8 bacterial CpGcontaining oligonucleotides, 9 and Toxoplasma gondii soluble tachyzoite antigen (STAg) 10 known to promote potent T H 1 responses. Moreover, on in vivo transfer, antigen-pulsed CD8␣ ϩ DCs induced CD4 ϩ T cells with a T H 1 cytokine profile, while similarly treated CD8␣ Ϫ DCs promoted a T H 2-dominated response. 11 In addition, the CD8␣ ϩ subset has been shown to play a preferential role in the induction of cytotoxic T cells by cross-priming. 12 However, this association of CD8␣ ϩ DCs with the induction of cell-mediated immunity is not absolute because additional evidence indicates that under some circumstances some CD8␣ Ϫ DCs can produce IL-12 and induce T H 1 responses. 13 In the present study, we have investigated host factors that control the differentiation of CD8␣ ϩ DCs in vivo. Our approach was to isolate CD8␣ ϩ and CD8␣ Ϫ DCs from mouse spleen and to screen by representational difference analysis (RDA) for genes expressed uniquely in the CD8␣ ϩ subset. One gene that showed a preferential association with CD8␣ ϩ DCs was that encoding interferon consensus sequence binding protein (ICSBP), a member of the interferon regulatory factor (IRF) gene family. Interestingly, this transcription factor had previously been shown to play a preferential role in the induction of IL-12p40 express...

IL-17–producing CD27 − γδ cells (γδ 27− cells) are widely viewed as innate immune cells that make critical contributions to host protection and autoimmunity. However, factors that promote them over IFN-γ–producing γδ 27+ cells are poorly elucidated. Moreover, although human IL-17–producing γδ cells are commonly implicated in inflammation, such cells themselves have proved difficult to isolate and characterize. Here, murine γδ 27− T cells and thymocytes are shown to be rapidly and substantially expanded by IL-7 in vitro and in vivo. This selectivity owes in substantial part to the capacity of IL-7 to activate STAT3 in such cells. Additionally, IL-7 promotes strong responses of IL-17–producing γδ cells to TCR agonists, thus reemphasizing the cells’ adaptive and innate potentials. Moreover, human IL-17–producing γδ cells are also substantially expanded by IL-7 plus TCR agonists. Hence, IL-7 has a conserved potential to preferentially regulate IL-17–producing γδ cells, with both biological and clinical implications.

To assess directly the role of protein kinase C (PKC)ε in the immune system, we generated mice that carried a homozygous disruption of the PKCε locus. PKCε−/− animals appeared normal and were generally healthy, although female mice frequently developed a bacterial infection of the uterus. Macrophages from PKCε−/− animals demonstrated a severely attenuated response to lipopolysaccharide (LPS) and interferon (IFN)γ, characterized by a dramatic reduction in the generation of NO, tumor necrosis factor (TNF)-α, and interleukin (IL)-1β. Further analysis revealed that LPS-stimulated macrophages from PKCε−/− mice were deficient in the induction of nitric oxide synthase (NOS)-2, demonstrating a decrease in the activation of IκB kinase, a reduction in IκB degradation, and a decrease in nuclear factor (NF)κB nuclear translocation. After intravenous administration of Gram-negative or Gram-positive bacteria, PKCε−/− mice demonstrated a significantly decreased period of survival. This study provides direct evidence that PKCε is critically involved at an early stage of LPS-mediated signaling in activated macrophages. Furthermore, we demonstrate that in the absence of PKCε, host defense against bacterial infection is severely compromised, resulting in an increased incidence of mortality.

Cancer-associated inflammation mobilizes a variety of leukocyte populations that can inhibit or enhance tumor cell growth in situ. These subsets include γδ T cells, which can infiltrate tumors and typically provide large amounts of antitumor cytokines, such as IFN-γ. By contrast, we report here that in a well-established transplantable (ID8 cell line) model of peritoneal/ovarian cancer, γδ T cells promote tumor cell growth. γδ T cells accumulated in the peritoneal cavity in response to tumor challenge and could be visualized within solid tumor foci. Functional characterization of tumor-associated γδ T cells revealed preferential production of interleukin-17A (IL-17), rather than IFN-γ. Consistent with this finding, both T cell receptor (TCR)δ-deficient and IL-17-deficient mice displayed reduced ID8 tumor growth compared with wild-type animals. IL-17 production by γδ T cells in the tumor environment was essentially restricted to a highly proliferative CD27 (−) subset that expressed Vγ6 instead of the more common Vγ1 and Vγ4 TCR chains. The preferential expansion of IL-17-secreting CD27 (−) Vγ6 (+) γδ T cells associated with the selective mobilization of unconventional small peritoneal macrophages (SPMs) that, in comparison with large peritoneal macrophages, were enriched for IL-17 receptor A, and for protumor and proangiogenic molecular mediators, which were upregulated by IL-17. Importantly, SPMs were uniquely and directly capable of promoting ovarian cancer cell proliferation. Collectively, this work identifies an IL-17-dependent lymphoid/myeloid crosstalk involving γδ T cells and SPMs that promotes tumor cell growth and thus counteracts cancer immunosurveillance. gamma-delta T cells | tumor immunologyD eveloping tumors are infiltrated by a variety of leukocyte subsets that can either promote or inhibit inflammation, and thus impact on cancer progression (1). Among such populations are γδ T cells, which are major players in lymphoid stress surveillance likely due to their recognition of stress-inducible molecules independently of MHC-mediated antigen presentation (2). Moreover, abundant IFN-γ secretion and cytotoxic effector functions endow γδ T cells with potent antitumor activity. This has been clearly documented in murine models of spontaneous (3), chemically induced (4), transgenic (5), and transplantable (6, 7) tumors. For example, in the widely used B16 melanoma model, γδ T cells were shown to infiltrate tumors very early and provided a critical source of IFN-γ that significantly delayed tumor growth (6, 7).Human γδ T cells also possess IFN-γ-secreting potential, which is displayed immediately at birth (8) and display cytotoxicity against tumor lines of diverse origin, including epithelial (9, 10) and hematological (11,12) tumors. This has prompted the development of cancer clinical trials targeting γδ T cells, which have produced encouraging, albeit highly variable, degrees of therapeutic responses (13-15). There is therefore great interest in maximizing the antitumor functions of γδ T cells for cancer ...