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Foxp3+ regulatory T cells (Tregs) play a critical role in maintaining immune self-tolerance. Reduced number and activity of Tregs are usually found in autoimmune and inflammatory diseases, and enhancing the differentiation of Tregs may be a promising therapeutic strategy. Some reports suggested an anti-inflammatory and anti-autoimmune potential for fenofibrate, a hypolipidemic drug used worldwide, whose lipid effects are mediated by the activation of peroxisome proliferator-activated receptor α (PPARα). In the present paper, we found that fenofibrate dose-dependently increased transforming growth factor-β and interleukin-2-induced Treg differentiation in vitro, by 1.96-fold from 0 to 20 μM(12.59±1.34% to 24.69±3.03%,P < 0.05). Other PPARα activators, WY14643 (100 μM), gemfibrozil (50μM), and bezafibrate (30 μM), could not enhance Treg differentiation. In addition, PPARα could not upregulate the promoter activity of the Treg-specific transcription factor Foxp3. Fenofibrate might exert its function by enhancing Smad3 phosphorylation, a critical signal in Treg differentiation, via Akt suppression. Our work reveals a new PPARα independent anti-inflammatory mechanism of fenofibrate in up-regulating mouse Treg differentiation. [ABSTRACT FROM AUTHOR]

Abstract: The microsporidia are emerging agents of infectious disease in both immunocompromised and immunocompetent mammals. Recently, there has been an increased interest in studying the immunobiology of microsporidiosis. This paper discusses the humoral and cell-mediated immune responses to Encephalitozoon spp. The T-cell-mediated responses appear to be most important in conferring resistance. This has become evident by the lethal effects of microsporidiosis in T-cell-deficient hosts. However, much still needs to be learned about the immunobiology of microsporidiosis regarding the specific T-cell responses and the cytokines that provide protective immunity and facilitate the macrophage-mediated killing of microsporidia. Such information will become important in developing immunotherapeutic strategies to control microsporidiosis in the future. [Copyright &y& Elsevier]

Chronic nonbacterial osteomyelitis (CNO) with its most severe form chronic recurrent multifocal osteomyelitis (CRMO) is a non-bacterial osteitis of yet unknown origin. Secondary to the absence of both high-titer autoantibodies and autoreactive T lymphocytes, and the association with other autoimmune diseases, it was recently reclassified as an autoinflammatory disorder of the musculoskeletal system. Since its etiology is largely unknown, the diagnosis is based on clinical criteria, and treatment is empiric and not always successful. In this paper, we summarize recent advances in the understanding of possible etiopathogenetic mechanisms in CNO. [ABSTRACT FROM AUTHOR]

Dendritic cells (DCs) competent to express the regulatory enzyme IDO in mice are a small but distinctive subset of DCs. Previously, we reported that a high-dose systemic CpG treatment to ligate TLR9 in vivo induced functional IDO exclusively in splenic CD19+ DCs, which stimulated resting Foxp3-lineage regulatory T cells (Tregs) to rapidly acquire potent suppressor activity. In this paper, we show that IDO was induced in spleen and peripheral lymph nodes after CpG treatment in a dose-dependent manner. Induced IDO suppressed local T cell responses to exogenous Ags and inhibited proinflammatory cytokine expression in response to TLR9 ligation. IDO induction did not occur in T cell-deficient mice or in mice with defective B7 or programmed death (PD)-1 costimulatory pathways. Consistent with these findings, CTLA4 or PD-1/PD-ligand costimulatory blockade abrogated IDO induction and prevented Treg activation via IDO following high-dose CpG treatment. Consequently, CD4+CD25+ T cells uniformly expressed IL-17 shortly after TLR9 ligation. These data support the hypothesis that constitutive interactions from activated T cells or Tregs and IDO-competent DCs via concomitant CTLA4→B7 and PD-1→PD-ligand signals maintain the default potential to regulate T cell responsiveness via IDO. Acute disruption of these nonredundant interactions abrogated regulation via IDO, providing novel perspectives on the proinflammatory effects of costimulatory blockade therapies. Moreover, interactions between IDO-competent DCs and activated T cells in lymphoid tissues may attenuate proinflammatory responses to adjuvants such as TLR ligands. [ABSTRACT FROM AUTHOR]

There are large numbers of T-cells in the mucosa of the intestine in healthy individuals. The stimulus for their presence is the normal gut microbiota. For unknown reasons, in patients with IBD (inflammatory bowel disease), there is inappropriate and chronic activation of mucosal T-cells which leads to gut damage and severe morbidity. In one form of IBD, namely Crohn's disease, the T-cells are probably responding to the microbiota. T-cell survival in the gut wall is dependent on pro-inflammatory cytokines and antibody-mediated inhibition of one of these cytokines, TNFα (tumour necrosis factor α), has shown efficacy in patients, thus encouraging investigations of other ways to control mucosal T-cell responses. In the present paper, we give a brief review of T-cell immunology in IBD and then discuss how two particular cytokines, namely IL-21 (interleukin 21), which is generally pro-inflammatory and important in gut T-cell survival and in maintaining Th17 cells, and TGFβ1 (transforming growth factor β1), which is generally immunosuppressive, play opposing roles in gut inflammation. [ABSTRACT FROM AUTHOR]

Abstract: Establishment of a leukemia plasmacytoid dendritic cell line (PMDC05) and intra-lineage transformation from pDCs to mDCs in PMDC05 has been reported. In this paper, we show the applicability of PMDC05 for cellular immunotherapy. By stimulation with LPS, PMDC05 showed enhancement in expression of antigen presentation-associated surface molecules and production of cytokines (IL-12p70 and TNF-α). The antigen presenting ability was markedly increased in PMDC05 stimulated with LPS. By co-culturing of CD8+ T cells with LPS-stimulated and WT1/CMVpp65 peptide-pulsed PMDC05, WT1/CMVpp65 tetramer+ cytotoxic T lymphocytes were efficiently generated. These findings reveal the applicability of PMDC05 in cellular immunotherapy for tumor and severe viral infections. [Copyright &y& Elsevier]

Abstract: Some self-reactive immature T cells escape negative selection in the thymus and may cause autoimmune diseases later. In the periphery, if T cells are stimulated insufficiently by peptide-major histocompatibility complex, they become inactive and their production of cytokines changes, a phenomenon called “T cell anergy”. In this paper, we explore the hypothesis that T cell anergy may function to reduce the risk of autoimmunity. The underlying logic is as follows: Since those self-reactive T cells that receive strong stimuli from self-antigens are eliminated in the thymus, T cells that receive strong stimuli in the periphery are likely to be non-self-reactive. As a consequence, when a T cell receives a weak stimulus, the likelihood that the cell is self-reactive is higher than in the case that it receives a strong stimulus. Therefore, inactivation of the T cell may reduce the danger of autoimmunity. We consider the formalism in which each T cell chooses its response depending on the strength of stimuli in order to reduce the risk of autoimmune diseases while maintaining its ability to attack non-self-antigens effectively. The optimal T cell responses to a weak and a strong stimulus are obtained both when the cells respond in a deterministic manner and when they respond in a probabilistic manner. We conclude that T cell anergy is the optimal response when a T cell meets with antigen-presenting cells many times in its lifetime, and when the product of the autoimmunity risk and the number of self-reactive T cells has an intermediate value. [Copyright &y& Elsevier]

T-lymphocytes are believed to play an important role in the pathogenesis of discoid lupus erythematosus (DLE). However, the reasons that lead to loss of tolerance and to development of autoimmunity in DLE remain unclear. In the present paper, we investigated serum levels of the regulatory cytokines transforming growth factor (TGF)-β and interleukin (IL)-10 in 25 newly diagnosed patients with DLE, 15 with systemic lupus erythematosus (SLE), 10 with psoriasis, 10 with atopic dermatitis (AD) and 20 healthy controls (HC). TGF-β serum levels were significantly lower in patients with DLE compared with patients with psoriasis and HC, while no differences were found between DLE, SLE and AD (medians: DLE: 28.49 ng/ml; psoriasis: 42.77 ng/ml; HC: 43.71 ng/ml; DLE vs. psoriasis: p < 0.05; DLE vs. HC: p < 0.05). IL-10 concentrations were reduced in DLE serum samples with respect to SLE, psoriasis, AD and HC (medians: DLE: 46.42 pg/ml; SLE: 127.64 pg/ml; psoriasis: 109.3 pg/ml; AD: 76.3 pg/ml; HC: 114.71 pg/ml; DLE vs. SLE: p < 0.05; DLE vs. psoriasis: p < 0.05; DLE vs. AD: p < 0.05; DLE vs. HC: p < 0.05). The downregulation of TGF-β and IL-10 in DLE may lead to defective immune suppression and thus to the generation of the tissue injury that is found in lupus patients. [ABSTRACT FROM AUTHOR]

Autoreactive CD8+ T lymphocytes play a key role in the pathogenesis of several autoimmune diseases. It is not yet well understood how autoreactive CD8+ T cells, which express TCRs with low reactivity toward self-Ags, gain the ability to respond to autoantigens to cause disease. Previously, we have shown that prior stimulation of CD8+ T cells with synergistic combinations of cytokines produced by the innate immune response, such as IL-21 and IL-15, induces Ag-independent proliferation. Such "cytokine-primed" CD8 T cells displayed increased responsiveness to limiting quantities of the cognate Ag. In this paper, we report that prior stimulation with IL-15 and IL-21 also enables CD8+ T cells to respond to weakly agonistic TCR ligands, resulting in proliferation, cytokine secretion, and cytolytic activity. Using a transgenic mouse model of autoimmune diabetes, we show that cytokine-primed autoreactive CD8+ T cells induce disease following stimulation by weak TCR ligands, but their diabetogenic potential is dependent on continuous availability of IL-15 in vivo. These findings suggest that inflammatory cytokines could facilitate the triggering of autoreactive CD8+ T cells by weak autoantigens, and this mechanism may have important implications for autoimmune diseases associated with microbial infections and chronic inflammation. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports the cloning and sequencing of interleukin (IL)-23 p19 subunit for the first time within a non-mammalian species, the zebrafish (Danio rerio), which was discovered using a synteny approach. In addition, amino acid sequences were for IL-23 p19 subunits were also predicted from the stickleback, Fugu and Tetraodon genomes and included in this investigation. The zebrafish IL-23 p19 cDNA consisted of a 66bp 5′ UTR, a 249bp 3′ UTR and a single open reading frame of 567bp giving a predicted 188 aa IL-23 p19 molecule. Multiple alignment of zebrafish IL-23 p19, with other known IL-23 p19 and IL-12 p35 amino acid sequences revealed areas of amino acid conservation, such as the presence of four predicted α-helixes, cysteines important for disulphide bond formation and the conservation of a tryptophan known to interact with the receptor. Amino acid homologies and phylogenetic analysis confirmed the relationship of the fish IL-23 p19 subunits with their mammalian homologues. All the teleost fish IL-23 p19 subunits were found to have 4 exons and 3 introns similar to that of human and mouse IL-23 p19 and a limited degree of synteny was found between the organisms for the regions containing the IL-23 p19 genes with only PAB-dependent poly(A)-specific ribonuclease subunit 2 (PAN2) and IL-23 p19 found in the same order on human chromosome 12 and all the fish genomes looked at. Lastly using real-time PCR, constitutive expression of IL-12 p40 and IL-23 p19 was observed in the kidney, liver, gut and muscle with IL-12 p40 expression higher than IL-23 p19. As soon as an hour after stimulation with LPS, there was an increase of IL-23 p19 in zebrafish leukocytes and an increase of IL-1β, IL-12 p40 and IL-23 p19 expression was found after infection of zebrafish for 1 or 6 days with Mycobaterium marinum strain E11. [Copyright &y& Elsevier]

Overexpression of the T cell cytokine IL-22 is linked to the development of some chronic diseases, but little is known about IL-22 deficiency in humans. As demonstrated in this study, acne inversa (AI; also designated as Hidradenitis suppurativa) lesions show a relative deficiency of IL-22 and IL-20, but not of IL-17A, IL-26, IFN-γ, IL-24, or IL-1β. Moreover, AI lesions had reduced expression of membranous IL-22 and IL-20 receptors and increased expression of the natural IL-22 inhibitor, IL-22 binding protein. AI is a chronic inflammatory skin disease with prevalence up to 4% of the population and in which cutaneous bacterial persistence represents an important pathogenetic factor. Accordingly, we also found a relative deficiency of antimicrobial proteins (AMPs) in AI lesions and a positive correlation between lesional IL-22 and IL-20 versus AMP levels. IL-22, like its tissue cell downstream mediator IL-20, upregulated AMPs in reconstituted human epidermis and was critical for increased AMP levels under inflammatory conditions. The relative IL-22 deficiency in AI was not linked to lesional T cell numbers or Th22/Th1/Th17 subset markers and -inducing cytokines. However, IL-10 was highly expressed in AI lesions and correlated negatively with IL-22 expression. Moreover, IL-10 inhibited IL-22 but not IL-17 production in vitro. The IL-10 overexpression, in turn, was not associated with an elevated presence of regulatory T cells but with the enhanced presence of an IL-10-inducing cytokine. We conclude that IL-22 deficiency may contribute to the pathogenesis of certain chronic disorders as postulated in this paper for AI. [ABSTRACT FROM AUTHOR]

Certain virus infections depend on the presence of T cell help for the generation of primary CD8+ T cell responses. However, the mechanisms that render these particular viral infections T cell help dependent is largely unknown. In this study, we compared CD8+ T cell responses elicited by lymphocytic choriomeningitis virus infection, as prototype of a T cell help independent infection, with T cell help dependent CD8+ T cell responses induced by vaccinia virus infection. In this paper, we show that a key parameter decisive for T cell help independence is the ability of an infectious agent to stimulate early and robust production of type I IFN. Experimental provision of type I IFN during VV infection rendered the ensuing CD8+ T cell response completely T cell help independent. Our results support a model in which type I IFN has to be present during the first 3 d of Ag encounter and has to act directly on the responding CD8+ T cells to promote their survival and effector differentiation. We show that type I IFN signaling on responding CD8+ T cells induces profound upregulation of CD25 and increased IL-2 expression; however, neither this nor IL- 15 accounts for the type I IFN effects on responding CD8+ T cells. Thus, type I IFN can effectively replace the requirement of T cell help by directly promoting CD8+ T cell survival and differentiation independent of the type I IFN-induced cytokines IL-2 and IL-15. [ABSTRACT FROM AUTHOR]

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with a multifaceted range of symptoms affecting almost every organ system. The prototypical pathology of SLE involves the production of antinuclear antibodies and the deposition of immune complexes in basement membranes throughout the body where they induce inflammatory responses. The genetic and environmental etiologies of this process are being intensively sought, and recently, TH17 cells have been implicated in the pathogenesis of SLE. TH17 cells are CD4+ memory T cells that behave as both helper and effector cell populations functioning through their signature IL-17 cytokines. Their differentiation is distinct to either the TH1 or TH2 cell lineage, but strongly influences development of adaptive responses, including autoimmunity. This paper details the biological functions and regulation of TH17 cells, followed by an update of their expanding role in SLE. [ABSTRACT FROM AUTHOR]

Candida albicans is an opportunistic fungal pathogen that normally exists as a harmless commensal in humans. In instances where host debilitation occurs, Candida can cause a range of clinical infections, and whilst these are primarily superficial, effecting mucosal membranes, systemic infections can develop in severely immunocompromised individuals. The mechanism of host immunity during commensal carriage of C. albicans has been intensively studied. In this paper, we present the most recent information concerning host recognition of C. albicans leading to cytokine production and the subsequent T-cell responses generated in response to C. albicans. Particular focus is given to the role of the IL-12 cytokine family including IL-12, IL-23, IL-27, and IL-35, in host immunity to Candida. CD4+ T-cells are considered crucial in the regulation of immunity and inflammation. In this regard, the role of Th1/2, helper cells, together with the recently identified Th17 and Treg cells in candidosis will be discussed. Understanding the detailed mechanisms that underlie host immunity to Candida not only will be of benefit in terms of the infections caused by this organism but could also be exploited in the development of therapeutic interventions for other diseases. [ABSTRACT FROM AUTHOR]

The immune system must balance the need to maintain a diverse repertoire of lymphocytes to be able to fight infection with the need to maintain tolerance to self-proteins. The immune system places strict regulation over the ability of T cells to produce the major T cell growth factor interleukin 2 as this cytokine can influence a variety of immune outcomes. T cells require the delivery of two signals, one through the antigen receptor and a second through the costimulatory receptor CD28. The immune system uses a variety of E3 ubiquitin ligases to target signaling proteins that function downstream of the TCR and CD28 receptors. Mutations in these E3 ligases can lead to a breakdown in immune tolerance and development of autoimmunity. This paper will examine the role of a range of E3 ubiquitin ligases and signaling pathways that influence the development of T-cell effector responses and the development of organ-specific autoimmune diseases such as type 1 diabetes. [ABSTRACT FROM AUTHOR]

The cytokines generated locally in response to infection play an important role in CD8 T cell trafficking, survival, and effector function, rendering these signals prime candidates for immune intervention. In this paper, we show that localized increases in the homeostatic cytokine IL-15 induced by influenza infection is responsible for the migration of CD8 effector T cells to the site of infection. Moreover, intranasal delivery of IL-15-IL-15Rα soluble complexes (IL-15c) specifically restores the frequency of effector T cells lost in the lung airways of IL-15-deficient animals after influenza infection. Exogenous IL-15c quantitatively augments the respiratory CD8 T cell response, and continued administration of IL-15c throughout the contraction phase of the anti-influenza CD8 T cell response magnifies the resultant CD8 T cell memory generated in situ. This treatment extends the ability of these cells to protect against heterologous infection, immunity that typically depreciates over time. Overall, our studies describe what to our knowledge is a new function for IL-15 in attracting effector CD8 T cells to the lung airways and suggest that adjuvanting IL-15 could be used to prolong anti-influenza CD8 T cell responses at mucosal surfaces to facilitate pathogen elimination. [ABSTRACT FROM AUTHOR]

T cell lines with defined cytokine profiles are an invaluable tool for assessing the control of immune responses both in vitro and in vivo. Production of such cell lines can be complex and time-consuming. Here we present a powerful technique to assay the cytokines produced by T cells activated polyclonally or with specific antigens. This paper presents a detailed methodology for the identification and isolation of cytokine-producing T cells activated with the artificial superantigen, CytoStim, or viral and fungal antigens. These cells can be analysed for different cytokines simultaneously, or cultured further to rapidly establish T cell lines making known cytokine types. We highlight the enumeration, isolation and phenotype of interleukin-17-producing T cells, and the rapid generation of virus-specific Th1 T cell lines. [ABSTRACT FROM AUTHOR]

CD8 T cells are essential for control of Toxoplasma gondii infection. Once activated they undergo differentiation into short-lived effector and memory precursor effector cells. As effector cells, CD8 T cells exert immune pressure on the parasite via production of inflammatory cytokines and through their cytolytic activity. Once immune control has been established, the parasite encysts and develops into chronic infection regulated by the memory CD8 T-cell population. Several signals are needed for this process to be initiated and for development of fully differentiated memory CD8 T cells. With newly developed tools including CD8 Tcell tetramers and TCR transgenic mice, dissecting the biology behind T. gondii-specific CD8 T-cell responses can now be more effectively addressed. In this paper, we discuss what is known about the signals required for effective T. gondii-specific CD8 T-cell development, their differentiation, and effector function. [ABSTRACT FROM AUTHOR]

Please cite this paper as: Mier-Cabrera J, Jiménez-Zamudio L, García-Latorre E, Cruz-Orozco O, Hernández-Guerrero C. Quantitative and qualitative peritoneal immune profiles, T-cell apoptosis and oxidative stress-associated characteristics in women with minimal and mild endometriosis. BJOG 2011;118:6-16. To assess immunological variables, T-cell apoptosis and oxidative stress markers in the peripheral blood and peritoneal fluid of women with (WEN) and without (WWE) endometriosis. Observational and transverse case-control study. National Institute of Perinatology, Mexico City, Mexico. Peripheral blood and peritoneal fluid obtained from 30 WWE and 32 WEN. Blood was drawn before surgery and peritoneal fluid was collected during surgery but before any surgical procedure had been carried out. Flow cytometry, spectrophotometry, high-performance liquid chromatography and multiplex immunoassay analyses were performed. Peripheral and peritoneal lymphocyte subpopulations (CD3, CD4 CD3, CD8 CD3, CD16 CD56, human leucocyte antigen-DR CD3 and CD19), intracellular CD4 CD3 and CD8 CD3 cytokine synthesis (interleukin-2 [IL-2] and interferon-γ [IFN-γ]), CD3 apoptosis, malondialdehyde and ascorbate concentrations and peritoneal cytokine concentrations. No differences were found in peripheral and peritoneal lymphocyte subsets between the groups. Peritoneal T lymphocytes from WEN produced less IL-2 and IFN-γ than those from WWE. Peritoneal malondialdehyde concentrations were higher and ascorbate concentrations were lower in WEN than in WWE. Higher peritoneal concentrations of pro-inflammatory cytokines (IL-1β, tumour necrosis factor-α and IL-6) and chemokines (IL-10, IL-8, eotaxin, vascular endothelial growth factor, monocyte chemotactic protein-1 and regulated upon activation, normal T-cell expressed, and secreted) and lower concentrations of IFN-γ, IL-1 receptor antagonist and IL-15 were found in WEN. No statistical differences were found in IL-2, IL-4, IL-12 and IL-13 concentrations. The alterations observed in WEN were associated with a diminished peritoneal T helper type 1 immune response. Pro-inflammatory, chemotactic, angiogenic and oxidative stress markers were altered in the peritoneal milieu of WEN. These changes appeared to contribute to the peritoneal immune alterations found. [ABSTRACT FROM AUTHOR]

Please cite this paper as: In vitro and in vivo analysis of pro- and anti-inflammatory effects of weak and strong contact allergens. Experimental Dermatology 2010; : 1007-1013. Inflammation is a crucial step in the development of allergic contact dermatitis. The primary contact with chemical allergens, called sensitization, and the secondary contact, called elicitation, result in an inflammatory response in the skin. The ability of contact allergens to induce allergic contact dermatitis correlates to a great extent with their inflammatory potential. Therefore, the analysis of the sensitizing potential of a putative contact allergen should include the examination of its ability and potency to cause an inflammation. In this study, we examined the inflammatory potential of different weak contact allergens and of the strong sensitizer 2,4,6-trinitrochlorobenzene (TNCB) in vitro and in vivo using the contact hypersensitivity model, the mouse model for allergic contact dermatitis. Cytokine induction was analysed by PCR and ELISA to determine mRNA and protein levels, respectively. Inflammation-dependent recruitment of skin-homing effector T cells was measured in correlation with the other methods. We show that the sensitizing potential of a contact allergen correlates with the strength of the inflammatory response. The different methods used gave similar results. Quantitative cytokine profiling may be used to determine the sensitizing potential of chemicals for hazard identification and risk assessment. [ABSTRACT FROM AUTHOR]

Several vaccination trials are evaluating the modified vaccinia virus Ankara (MVA) as a delivery vector in various clinical settings. In this paper, we present the reevaluation of a therapeutic vaccination trial in human immunodeficiency virus (HIV)-1-infected individuals treated with highly active antiretroviral therapy using MVA-expressing HIV-1 nef. Immunogenicity of MVA-nef was assessed using multicolor flow cytometry. Vaccine-induced polyfunctionality and proliferative capacity, which are associated with nonprogressive HIV-1 infection, were detectable by combining two immune assays. By means of short-term polychromatic intracellular cytokine staining, we observed a significant increase in polyfunctional Nef-specific CD4 T cells expressing interferon-γ, interleukin (IL)-2 and CD154 after vaccination, whereas changes in the quality of CD8 T-cell response could not be observed. Only the additional use of a long-term polychromatic Carboxyfluorescein succinimidyl ester (CFSE)-based proliferation assay revealed vaccine-induced Nef-specific CD8, as well as CD4 T cells with proliferative capacity. The correlation between vaccine-induced IL-2 production by CD4 T cells and the increase in proliferating Nef-specific CD8 T cells suggests a causal link between these two functions. These results highlight the importance of combining sophisticated immunomonitoring tools to unravel concealed effects of immunological interventions and support the use of the poxvirus-derived MVA vector to stimulate highly functional HIV-1-specific T-cell responses. However, the clinical benefit of these functional T cells remains to be determined. [ABSTRACT FROM AUTHOR]

Abstract: Cytokine secretion by leukocytes is an important indicator of immune response to pathogens and therefore has significant implications in disease diagnostics. Given heterogeneity of leukocyte subsets and the ability of multiple cell subsets to secrete the same cytokines, connecting cytokine production to a specific leukocyte subset is a distinct challenge. In the present paper we describe a strategy combining antibody (Ab)-based affinity cell separation and surface plasmon resonance (SPR) for capturing human CD4 T-cells and for label-free detection of cell-secreted interferon (IFN)-γ – an important inflammatory cytokine. Human blood was introduced into a flow chamber modified with anti-CD4 Abs resulting in capture of CD4+ T-cells. After mitogenic activation of cells inside the flow chamber, culture medium was routed onto an SPR chip modified with monoclonal IFN-γ Abs. SPR signal observed in this experiment correlated with cytokine production by T-cells. The strategy of combining SPR detection with cell purification may be used in the future for label-free, sensitive detection of multiple cytokines or proteins secreted by the desired cell subset. [Copyright &y& Elsevier]

Please cite this paper as: T-lymphocyte-induced, fas-mediated apoptosis is associated with early keratinocyte differentiation. Experimental Dermatology 2009. The development of eczematous lesions is thought to be due in part to a breakdown in skin barrier function as a result of T lymphocytes (T cells) invading the skin causing epidermal keratinocyte apoptosis. In this study, we investigated the interaction of T cells and keratinocytes on apoptosis and terminal differentiation using an in vitro co-culture system. Experiments were performed using the HaCaT keratinocyte cell line or normal human epidermal keratinocytes. Activated human peripheral blood-derived T cells were found to induce Fas-dependent keratinocyte apoptosis by up to sixfold. Increased Fas was associated with increased IFN-γ. The T-cell apoptotic signal was found to target preferentially keratinocytes in the very early stages of terminal differentiation, such as those with low levels of α6-integrin expression, and result in subsequent increased caspase 3 activity. This observation was accompanied by a marked increase in keratinocyte ICAM-1 expression and its ligand LFA-1 on T cells. Our data suggest that T cells may initiate the onset of keratinocyte terminal differentiation making them more susceptible to Fas-dependent cell death signals delivered by the T cells. [ABSTRACT FROM AUTHOR]

Please cite this paper as: MAP17 is associated with the T-helper cell cytokine-induced down-regulation of filaggrin transcription in human keratinocytes. Experimental Dermatology 2009. In the meta-analysis of public microarray databases for different skin diseases, we revealed seven commonly up-regulated genes, DSG3, KRT6, MAP17, PLSCR1, RPM2, SOD2 and SPRR2B. We postulated that the genes selected from the meta-analysis may be potentially associated with the abnormal keratinocyte differentiation. To demonstrate this postulation, we alternatively evaluated whether the genes of interest in the meta-analysis can be regulated by T-helper (Th) cell cytokines in normal human epidermal keratinocytes (NHEK). We found that MAP17 was significantly up-regulated in response to interferon-γ, interleukin 4 (IL-4), IL-6, IL-17A or IL-22 in NHEK. Interestingly, MAP17 was originally reported to interact with PDZK1; in turn, the PDZK1 gene is localized within the atopic dermatitis-linked region on human chromosome 1q21. In an attempt to evaluate whether MAP17 regulates the expression of cornified envelope-associated genes at the 1q21 locus, such as filaggrin, loricrin and involucrin, we found that the over-expression of MAP17 in HaCaT keratinocytes significantly decreased the expression of filaggrin. Taken together, the Th cell cytokine-induced up-regulation of MAP17 expression may be linked to the down-regulation of filaggrin in NHEK, which may be associated with the abnormal epidermal differentiation observed in the dermatological diseases. [ABSTRACT FROM AUTHOR]

OTHER ARTICLES PUBLISHED IN THIS MINI-REVIEW SERIES ON Th17 CELLS Function and regulation of human T helper 17 cells in health and disease. Clin Exp Immunol 2009; doi:10.1111/j.1365-2249.2009.04037.x Are T helper 17 cells really pathogenic in autoimmunity? Clin Exp Immunol 2009; doi:10.1111/j.1365-2249.2009.04039.x CD4+ T helper cells: functional plasticity and differential sensitivity to regulatory T cell-mediated regulation. Clin Exp Immunol 2009; doi:10.1111/j.1365-2249.2009.04040.x Development of mouse and human T helper 17 cells. Clin Exp Immunol 2009; doi:10.1111/j.1365-2249.2009.04041.x Uncommitted (naive) CD4+ T helper cells (Thp) can be induced to differentiate to specific lineages according to the local cytokine milieu, towards T helper type 1 (Th1), Th2, Th17 and regulatory T cell (Treg) phenotypes in a mutually exclusive manner. Each phenotype is characterized by unique signalling pathways and expression of specific transcription factors, notably T-bet for Th1, GATA-3 for Th2, forkhead box P3 (FoxP3) for Tregs and receptor-related orphan receptor (ROR)α and RORγt for Th17 cells. Tregs and Th17 cells have been demonstrated to arise from common precursors in a reciprocal manner based on exposure to transforming growth factor (TGF)-β or TGF-β plus interleukin (IL)-6 and carry out diametrically opposing functions, namely suppression or propagation of inflammation, respectively. However, while epigenetic modifications in Th1 and Th2 differentiated cells prevents their conversion to other phenotypes, Th17 cells generated in vitro using TGF-β and IL-6 are unstable and can convert to other phenotypes, especially Th1, both in vitro and in vivo. Tregs are generated from naive precursors both in the thymus (natural, nTregs) and in the periphery (induced, iTregs). The highly suppressive function of Tregs enables them to control many inflammatory diseases in animals and makes them particularly attractive candidates for immunotherapy in humans. The stability of the Treg phenotype is therefore of paramount importance in this context. Recent descriptions of Treg biology have suggested that components of pathogens or inflammatory mediators may subvert the suppressive function of Tregs in order to allow propagation of adequate immune responses. Unexpectedly, however, a number of groups have now described conversion of Tregs to the Th17 phenotype induced by appropriate inflammatory stimuli. These observations are particularly relevant in the context of cell therapy but may also explain some of the dysregulation seen in autoimmune diseases. In this paper, we review Treg to Th17 conversion and propose some potential mechanisms for this phenomenon. [ABSTRACT FROM AUTHOR]

OTHER ARTICLES PUBLISHED IN THIS MINI-REVIEW SERIES ON Th17 CELLS Function and regulation of human T helper 17 cells in health and disease. Clin Exp Immunol 2009; doi:10.1111/j.1365-2249.2009.04037.x Induction of interleukin-17 production by regulatory T cells. Clin Exp Immunol 2009; doi:10.1111/j.1365-2249.2009.04038.x Are T helper 17 cells really pathogenic in autoimmunity? Clin Exp Immunol 2009; doi:10.1111/j.1365-2249.2009.04039.x CD4+ T helper cells: functional plasticity and differential sensitivity to regulatory T cell-mediated regulation. Clin Exp Immunol 2009; doi:10.1111/j.1365-2249.2009.04040.x There has been a considerable amount of interest in the immunological community about new phenotypic subsets of CD4+ T cells, particularly cells that produce the cytokine interleukin (IL)-17 [named T helper type 17 (Th17) cells]. While the initial discovery of Th17 cells and the pathways that controlled their development was in the mouse, recent attention has shifted to the existence of these cells and the relevant upstream cytokine signals in humans. While it is clear that CD4+ T cells producing IL-17 exist in vivo, their relevance to disease pathogenesis is only just being understood. In this paper, we review the data regarding the generation of human Th17 cells in vitro and the evidence that this effector population is important in human disease states. [ABSTRACT FROM AUTHOR]

Although immunodeficiency is usually considered a prerequisite of oncogenesis, a detailed immune profile in cancer has not yet been described. Without such profiling, it is not surprising that there is a vast discrepancy in the responses of cancer patients to immunotherapy. Our results show that the integrity of the immune system deteriorates with cancer progression by displaying a trend toward decreasing levels of functional T cells, including CD4, naïve, and central memory T cells, and an expansion of hyporesponsive populations such as CD28− and CMV-specific T cells. One hundred and one patients constitute the study group for the observational study reported in this paper. Forty-eight patients with newly diagnosed stages III and IV and 53 patients with extensively treated stage IV disease. The costimulatory molecules CD27 and CD28 were downregulated in all patients. Among the proinflammatory cytokines (IL-6, TNF-α, IFN-γ), only IL-6 differed significantly among the groups, increasing as the cancer stage progressed. Plasma IL-7 did not differ among the participants. The relative deficits of naïve T cells in cancer patients may be associated with the downregulation of IL-7Rα expression rather than changes in the circulating levels of IL-7. The downregulation of IL-7Rα expression was shown to be associated with increased levels of intracellular CMV. The present study suggests that the immune impairment in patients with cancer is associated with multiple factors, such as the stage of cancer, consequence of CMV infection and impact of treatment. [ABSTRACT FROM AUTHOR]

Background: Altered levels of Immunoglobulin E (IgE) represent a dysregulation of IgE synthesis and may be seen in a variety of immunological disorders. The object of this review is to summarize the historical and molecular aspects of IgE synthesis and the disorders associated with dysregulation of IgE production. Methods: Articles published in Medline/PubMed were searched with the keyword Immunoglobulin E and specific terms such as class switch recombination, deficiency and/or specific disease conditions (atopy, neoplasia, renal disease, myeloma, etc.). The selected papers included reviews, case reports, retrospective reviews and molecular mechanisms. Studies involving both sexes and all ages were included in the analysis. Results: Both very low and elevated levels of IgE may be seen in clinical practice. Major advancements have been made in our understanding of the molecular basis of IgE class switching including roles for T cells, cytokines and T regulatory (or Treg) cells in this process. Dysregulation of this process may result in either elevated IgE levels or IgE deficiency. Conclusion: Evaluation of a patient with elevated IgE must involve a detailed differential diagnosis and consideration of various immunological and non-immunological disorders. The use of appropriate tests will allow the correct diagnosis to be made. This can often assist in the development of tailored treatments. [ABSTRACT FROM AUTHOR]

Systemic lupus erythematosus (SLE) is a complex systemic autoimmune disease with involvement of both B cells and cytotoxic T lymphocytes and several cytokines aberrations. Standard therapy for SLE has its limitations. Tacrolimus, a novel calcineurin inhibitor with potent immunosuppressive effects, has been shown in the recent years to be effective in SLE therapy. This paper serves to collate the experimental and clinical data on the efficacy of tacrolimus in the treatment of SLE and lupus nephritis. Tacrolimus as a key component of multitarget therapy in SLE is also discussed. The immunocytokine modulatory effects of tacrolimus are also reviewed with reference to SLE. It can be concluded that tacrolimus has an established role in the management of SLE. [ABSTRACT FROM AUTHOR]

Cytokine-induced killer (CIK) cells are polyclonal T effector cells generated when cultured under cytokine stimulation. CIK cells exhibit potent, non-MHC-restricted cytolytic activities against susceptible tumor cells of both autologous and allogeneic origins. Over the past 20 years, CIK cells have evolved from experimental observations into early clinical studies with encouraging preliminary efficacy towards susceptible autologous and allogeneic tumor cells in both therapeutic and adjuvant settings. This paper is our attempt to summarize the available published literature related to CIK cells. Looking into the future, we anticipate that the continuous therapeutic application of CIK cells will likely be developed along two major directions: overcoming the challenge to organize large prospective randomized clinical trials to define the roles of CIK cells in cancer immunotherapy and expanding its spectrum of cytotoxicity towards resistant tumor cells through experimental manipulations. [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) has traditionally been considered to be a T cell-mediated disease. However, there is an increasing body of evidence for the involvement of B cells and autoantibodies in the pathology of this disease, providing a rationale for treatment strategies directed against B cells. This paper summarizes the evidence for a key role of B cells in the immunopathology of MS and reviews data supporting the use of a novel B cell-targeted therapy, atacicept, for this condition. Atacicept is a human recombinant fusion protein that comprises the binding portion of a receptor for both BLyS (B Lymphocyte Stimulator) and APRIL (A PRoliferation-Inducing Ligand), two cytokines that have been identified as important regulators of B cell maturation, function and survival. Atacicept has shown selective effects on cells of the B cell lineage, acting on mature B cells and blocking plasma cells and late stages of B cell development while sparing B cell progenitors and memory cells. The efficacy of atacicept in animal models of autoimmune disease and the biological activity of atacicept in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) has been demonstrated. Ongoing clinical studies are investigating the safety, tolerability and efficacy of atacicept in patients with MS, SLE and RA. [ABSTRACT FROM AUTHOR]

The inflammatory bowel diseases (Crohn's disease; ulcerative colitis) are idiopathic chronic inflammatory disorders of the intestine and/or colon. A major advancement in our understanding of the pathogenesis of these diseases has been the development of mouse models of chronic gut inflammation. One model that has been instrumental in delineating the immunological mechanisms responsible for the induction as well as regulation of intestinal inflammation is the T cell transfer model of chronic colitis. This paper presents a detailed protocol describing the methods used to induce chronic colitis in mice. Special attention is given to the immunological concepts that explain disease pathogenesis in this model, considerations and potential pitfalls in using this model, and finally different "tricks" that we have learned over the past 12 years that have allowed us to develop a more simplified version of this model of experimental IBD. [ABSTRACT FROM AUTHOR]

Human interleukin-7 (hIL-7) is a cytokine secreted by the stromal cells of the red marrow. It is important for proliferation during certain stages of B-cell maturation and for T and NK cell survival, development, and homeostasis. It is a critical growth factor for enhancement and recovery of the immune T-cell. Because of its strong immunomodulatory effects, hIL-7 may become a valuable supplementary agent for immunotherapeutical treatments in patients with HIV infection or immunodeficiency. Human IL-7 has previously been produced in various protein expression systems. In this paper, we present an alternative expression system, in Spodoptera frugiperda cells, for the production of hIL-7 using nonlytic vector systems. This system allows generation of correctly translated and accurately processed heterologous proteins as soluble recombinant proteins. Here we report plasmid construction, transfection, and consequent expression of hIL-7 using this nonlytic insect cell expression system. The levels of secreted hIL-7 in a small scale experiment reached a level of 1.7 μg·1-1 under serum-free cell culture conditions. [ABSTRACT FROM AUTHOR]

Abstract Introduction  The immune response is controlled by several inhibitory mechanisms. These mechanisms include regulatory T cells, which exist in multiple classes. Notable among these are Foxp3-expressing regulatory T cells (Treg), NKT cells, and Tr1 cells. Common to these mechanisms are inhibitory cytokines such as interleukin-10 and transforming growth factor-beta (TGF-β). TGF-β and Foxp3-expressing Treg cells are critical in maintaining self-tolerance and immune homeostasis. Discussions  The immune suppressive functions of TGF-β and Treg cells are widely acknowledged and extensively studied. Nonetheless, recent studies revealed the positive roles for TGF-β and Treg cells in shaping the immune system and the inflammatory responses. In this paper, we will discuss the role of these mechanisms in the control of immunity and autoimmunity and the mechanisms that underlie how these molecules control these responses. [ABSTRACT FROM AUTHOR]

Control of the acute phase of Trypanosoma cruzi infection is critically dependent on cytokine-mediated macrophage activation to intracellular killing, natural killer (NK) cells, CD4+ T cells, CD8+ T cells and B cells. Cell-mediated immunity in T. cruzi infection is also modulated by cytokines, but in addition to parasite-specific responses, autoimmunity can be also triggered. Importantly, cytokines may also play a role in the cell-mediated immunity of infected subjects. Here we studied the role of cytokines in the regulation of innate and adaptive immunity during the acute phase of T. cruzi infection in Wistar rats. Melatonin is an effective regulator of the immune system. Macrophages and T lymphocytes, which have melatonin receptors, are target cells for the immunomodulatory function of melatonin. In this paper melatonin was orally given via two protocols: prior to and concomitant with infection. Both treatments were highly effective against T. cruzi with enhanced action for the concomitant treatment. The data suggest an up-regulation of the TH-1 immune response as all analyzed parameters, interleukin (IL)-4, IL-10, transforming growth factor-β1 and splenocyte proliferation, displayed reduced levels as compared with the untreated counterparts. However, the direct effects of melatonin on immune cells have not been fully investigated during T. cruzi infection. We conclude that in light of the current results, melatonin exerted important therapeutic benefits through its immune regulatory effects. [ABSTRACT FROM AUTHOR]

Background: Regulatory T cells are central actors in the maintenance of tolerance of self-antigens or allergens and in the regulation of the intensity of the immune response during infections by pathogens. An understanding of the network of the interaction between regulatory T cells, antigen presenting cells and effector T cells is starting to emerge. Dynamical systems analysis can help to understand the dynamical properties of an interaction network and can shed light on the different tasks that can be accomplished by a network. Methodology and Principal Findings: We used a mathematical model to describe a interaction network of adaptive regulatory T cells, in which mature precursor T cells may differentiate into either adaptive regulatory T cells or effector T cells, depending on the activation state of the cell by which the antigen was presented. Using an equilibrium analysis of the mathematical model we show that, for some parameters, the network has two stable equilibrium states: one in which effector T cells are strongly regulated by regulatory T cells and another in which effector T cells are not regulated because the regulatory T cell population is vanishingly small. We then simulate different types of perturbations, such as the introduction of an antigen into a virgin system, and look at the state into which the system falls. We find that whether or not the interaction network switches from the regulated (tolerant) state to the unregulated state depends on the strength of the antigenic stimulus and the state from which the network has been perturbed. Conclusion/Significance: Our findings suggest that the interaction network studied in this paper plays an essential part in generating and maintaining tolerance against allergens and self-antigens. [ABSTRACT FROM AUTHOR]

The tryptophan-catabolizing enzyme indoleamine-2,3-dioxygenase (IDO) initiates the first and rate-limiting step of the kynurenine pathway. It is induced by proinflammatory cytokines such as interferon-β and interferon-γ and has established effects in the control of intracellular parasites. The recent detection of its decisive function in immune tolerance at the maternal–fetal interface stimulated various studies unraveling its regulatory effect on T cells in many pathologies. In the brain, IDO can be induced in microglia by interferon-γ-producing T helper (Th) 1 cells, thereby initiating a negative feedback loop which downmodulates neuroinflammation in experimental autoimmune encephalomyelitis (EAE), the animal model of multiple sclerosis (MS). This protective effect could to be counteracted by the production of neurotoxic metabolites of the kynurenine pathway such as quinolinic acid, which are produced upon IDO induction. Some metabolites of the kynurenine pathway can pass the blood–brain barrier and thus could act as neurotoxins, e.g., during systemic infection. In this paper, we give a brief overview on established immune regulatory functions of IDO, review recent data on IDO expression in the brain, and propose that autoimmune neuroinflammation and the increasingly appreciated neuronal damage in MS are linked by Th1-mediated IDO induction through subsequent synthesis of toxic metabolites of tryptophan. [ABSTRACT FROM AUTHOR]

Inappropriate T cell responses cause the four classical types of hypersensitivity immune reactions. All of these can target the kidney and cause distinct forms of glomerulonephritis. CD4+ T cells can mediate glomerular immunopathology by cytokine secretion, by activating effector cells such as macrophages or by inducing auto-antibodies or immune-complexes. Cytotoxic CD8+ T cell responses and failure of regulatory T cells may represent two additional types of anti-renal hypersensitivity. T cell activation is critically dependent on dendritic cells (DC), whose role in renal disease appears to be protective, but underlying mechanisms are largely unknown. In this paper, we summarized mechanistic information from rodent models on the roles of DC and T cells in glomerular immunopathology. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA) is represents the most common chronic inflammatory joint disease and is still a major medical challenge because of unsolved issues related to the etiologic and pathogenetic questions. Intensive research has been conducted over the last years that focused on the inappropriate activation of the immune system: although T cells have long been deemed to play a central role in the origin and propagation of joint inflammation, data accumulated so far have widened this perspective recognizing the contribution of other cells, as well as the major histocompatibility complex class II proteins and a composite set of costimulatory signals responsible for the production of proinflammatory cytokines and other soluble mediators implicated in tissue destruction typical of the disease. This paper will provide an insight into the immune system in RA, dissecting cellular and humoral aspects both in serum and in synovium of patients. [ABSTRACT FROM AUTHOR]

Dietary fish oil has immunomodulatory effects that are partly mediated by its effects on cytokine secretion. In this paper, we examine whether dietary fish oil has different effects on cytokine secretion by T cells and macrophages. Female BalbC mice were fed diets supplemented with 18% fish oil + 2% corn oil or 20% corn oil. Concanavalin A (ConA)- and LPS-induced TNF-alpha and IL-10 secretion by splenocytes was examined using ELISA. Dietary fish oil decreased ConA induced-, but increased LPS-induced, TNF-alpha and IL-10 secretion by total murine splenocytes. Dietary fish oil increased the number of splenocytes secreting TNF-alpha and IL-10, following stimulation with LPS, by 123 and 38%, respectively, but did not affect cytokine secretion by each cell, as determined using enzyme-linked immunospot. Spleens from mice fed the fish oil diet had over 2-fold higher proportion of macrophages with high expression of CD11b than spleens from mice fed the corn oil diet. In addition, fish oil increased the proportion of total and CD11b(+) splenocytes that expressed the LPS receptor complex molecules, CD14 and toll-like receptor (TLR)4/myeloid differentiation factor-2 (MD-2), by 85 and 28%, respectively. The increased proportion of macrophages expressing the LPS receptor complex molecules, CD14 and TLR4/MD-2, in spleens from mice fed the fish oil diet may explain the increased number of cells that secreted the cytokines after LPS stimulation. [ABSTRACT FROM AUTHOR]

This paper reviews the new biologic agents that selectively block the immunologic steps implicated in the pathogenesis of psoriasis. Four strategies have been targeted: reduction of the number of pathogenic T cells; inhibition of T-cell activation and migration; modulation of the immune system; and blockage of the activity of inflammatory cytokines. There are three classes: monoclonal antibodies, fusion proteins and recombinant cytokines or growth factors. The actions, efficacy and side-effect profile of the biologic agents, alefacept, efalizumab, etanercept and infliximab, are reviewed. [ABSTRACT FROM AUTHOR]

Antigen-specific CD4+ T cells play a critical role in protective immunity to many infectious pathogens. Although the antigen-specific CD4+ T cells can be measured by functional assays such as proliferation or cytokine enzyme-linked immunospot, such assays are limited to a specific function and cannot quantify anergic or suppressed T cells. In contrast, major histocompatiblity complex (MHC) class II tetramers can enumerate epitope-specific CD4+ T cells independent of function. In this paper, we report the construction of bovine leukocyte antigen MHC class II tetramers using a novel mammalian cell system to express soluble class II DRA/DRB3 molecules and defined immunodominant peptide epitopes of Anaplasma marginale major surface proteins (MSPs). Phycoerythrin-labeled tetramers were either loaded with exogenous peptide or constructed with the peptide epitope linked to the N terminus of the DRB3 chain. A DRB3*1101 tetramer loaded with MSP1a peptide F2-5B (ARSVLETLAGHVDALG) and DRB3*1201 tetramers loaded with MSP1a peptide F2-1-1b (GEGYATYLAQAFA) or MSP2 peptide P16-7 (NFAYFGGELGVRFAF) specifically stained antigen-specific CD4+ T cell lines and clones. Tetramers constructed with the T-cell epitope linked to the DRB3 chain were slightly better at labeling CD4+ T cells. In one cell line, the number of tetramer-positive T cells increased to approximately 94% of the CD4+ T cells after culture for 21 weeks with specific antigen. This novel technology should be useful to track the fate of antigen-specific CD4+ T-cell responses in cattle after immunization or infection with persistent pathogens, such as A. marginale, that modulate the host immune response. [ABSTRACT FROM AUTHOR]

Chronic obstructive pulmonary disease (COPD) is characterized by an excessive inflammatory response to inhaled particles, mainly tobacco smoking. T lymphocytes are important regulatory cells that secrete several cytokines and participate actively in this inflammatory response. According to the pattern of cytokines secreted, the immune response is classified as cytotoxic or type 1 [interferon (IFN)-γ-, interleukin (IL)-2-dependent] and humoral or type 2 (IL-4-, IL-5-, IL-10- and IL-13-dependent). This paper sought to compare the intracellular profile of cytokine expression determined by flow cytometry in T lymphocytes harvested from bronchoalveolar lavage (BAL) and peripheral blood in patients with COPD, smokers with normal lung function and never smokers. We found that BAL T lymphocytes from COPD patients had a higher percentage of positive stained cells for most of the cytokines analysed when compared to never smokers or smokers with normal lung function. Differences reached statistical significance for IL-4, IL-10 and IL-13, particularly in CD8+ T cells. Furthermore, the expression of most of these cytokines was related inversely to the degree of airflow obstruction present suggesting local activation and/or selective homing of T lymphocytes to the lungs in COPD patients. These observations were not reproduced in circulating T lymphocytes. These results suggest that BAL T lymphocytes in patients with COPD produce more cytokines than in controls and tend to show a type 2 pattern of intracellular cytokine expression, particularly a Tc-2 profile. This is related inversely to the degree of airflow obstruction present. [ABSTRACT FROM AUTHOR]

Background: The purpose of the present paper was to investigate dendritic cell (DC) and T-cell functions in patients with chronic hepatitis B (CHB) and determine whether therapeutic DC vaccines could restore T-cell function in those patients in vitro. Methods: Twelve patients with CHB and 10 normal control subjects with positivity for antibodies to hepatitis B surface and core antigens (anti-HBs and anti-HBc positivity) were enrolled in the present study. Phenotype analysis and allogeneic mixed lymphocyte reaction assay of DC from CHB patients and normal controls were made in the absence or presence of a cocktail of cytokines: interleukin-1β (IL-1β), prostaglandin E2 (PGE2), IL-6 and tumor necrosis factor-α (TNF-α). Autologous T-cell proliferation assays and the enzyme-linked immunospot (ELISPOT) method for detecting interferon-γ (IFN-γ)-producing CD8+ T cells were used to evaluate the efficacy of DC loaded in vitro with HBsAg or HBcAg. Results: The DC from CHB patients had a lower expression of costimulatory molecules CD80, CD86 and impaired allogeneic mixed lymphocyte reaction capacity compared to those from normal controls. However, the impaired DC function could be restored partially by cytokine cocktail supplemented in vitro. Mature DC loaded with HBsAg or HBcAg showed a greater capacity for autologous T-cell proliferation and antigen-specific IFN-γ production than immature DC. Moreover, as a DC -loading antigen, HBcAg was more immunogenic than HBsAg. Conclusions: The impaired function of DC in patients with CHB may be restored by supplementation in vitro with a cocktail of cytokines, and therapeutic DC vaccines might be effective to treat CHB infection in humans. [ABSTRACT FROM AUTHOR]

Costimulatory molecules are cell surface glycoproteins that can direct, modulate and fine-tune T-cell receptor signals. The B7-1/B7-2–CD28/CTLA-4 and ICOS–B7RP-1 pathway provides key second signals that can regulate the activation, inhibition and fine-tuning of T-lymphocyte responses. The expression of B7-1/B7-2–CD28/CTLA-4 molecules on clinical samples from patients with asthma have been well studied, and the results indicate that different extents of these molecules are expressed on the surface of various cells, and that the concentrations of soluble form of these molecules are elevated in the sera of patients with asthma. There is a burst of papers describing an important role for B7-1/B7-2–CD28/CTLA-4 pathway in the Th1/Th2 balance. Similarly, ICOS stimulates both Th1 and Th2 cytokine production but may have a preferential role in Th2 cell development. Moreover, The B7-1/B7-2–CD28/CTLA-4 and ICOS–B7RP-1 pathway has been suggested of being involved in the development of airway inflammation and airway hyperresponsiveness. Further study of the functions of the pathways within the CD28/CTLA-4–CD80/CD86 and ICOS–B7RP-1 superfamily individually and their interplay should provide insights into the pathogenesis of asthma, and has great therapeutic potential for treatment of asthma. [ABSTRACT FROM AUTHOR]

IL-15 is a pleiotropic cytokine that plays an important role in both the innate and adaptive immune system. IL-15 promotes the activation of neutrophils and macrophages, and is critical to DC function. In addition, IL-15 is essential to the development, homeostasis, function and survival of natural killer (NK) cells, NK T (NKT) cells and CD8 + T cells. Based on these properties, IL-15 has been proposed as a useful cytokine for immunotherapy. It is currently being investigated in settings of immune deficiency, for the in vitro expansion of T and NK cells, as well as an adjuvant for vaccines. In this paper, we will review the targeting of IL-15 for immunotherapy, with a particular emphasis on its effects on CD8 + T cells. [ABSTRACT FROM AUTHOR]

Lipoarabinomannans (LAMs) are major lipoglycans of the mycobacterial envelope and constitute immunodominant epitopes of mycobacteria. In this paper, we show that mannose-capped (ManLAM) and non-mannose- capped (PILAM) mycobacterial lipoglycans insert into T helper cell rafts without apparent binding to known receptors. T helper cells modified by the insertion of PILAM responded to CD3 cross-linking by decreasing type 1 (IL-2 and IFN-?) and increasing type 2 (IL-4 and IL-5) cytokine production. Modification by the mannose-capped ManLAMs had similar, but more limited effects on T helper cell cytokine production. When incorporated into isolated rafts, PILAMs modulated membrane-associated kinases in a dose-dependent manner, inducing increased phosphorylation of Src kinases and Cbp/PAG in Th1 rafts, while decreasing phosphorylation of the same proteins in Th2 rafts. Mycobacterial lipoglycans thus modify the signalling machineries of rafts/microdomains in T helper cells, a modification of the membrane organization that eventually leads to an overall enhancement of type 2 and inhibition of type 1 cytokine production. [ABSTRACT FROM AUTHOR]

Ghrelin, a novel gut–brain peptide predominantly produced by the stomach, displays strong growth hormone (GH)-releasing activity mediated by the hypothalamus–pituitary GH secretagogue receptor (GHS-R). Recently, the ghrelin receptor has also been detected in peripheral systems including immune tissues, suggesting that ghrelin may play an important role in the regulation of immune function. In this paper, we assessed the presence and function of the ghrelin receptor in murine splenic T cells. The enriched T cells express the mRNA of ghrelin and ghrelin receptor mRNA, and there is a significantly positive correlation between them. Moreover, we showed that ghrelin dose-dependently inhibits proliferation of splenic T cells when they are costimulated by anti-CD3. In addition, ghrelin suppressed Th1 (IL-2 and IFN-γ) and Th2 (IL-4 and IL-10) cytokines mRNA expression. These results demonstrate the presence of the ghrelin receptor in murine spleen T lymphocytes and a functional role of ghrelin as a modulator of lymphocyte function. This function of ghrelin may have some relevance to the pathophysiology of immunologic alterations related to metabolism. [Copyright &y& Elsevier]

Effector T lymphocyte responses are considered critical for controlling human immunodeficiency virus type-1 (HIV-1) infection. The enzyme-linked immunospot (ELISpot) assay has emerged as a primary means of assessing HIV-specific T cell responses, and the development of objective methods that distinguish positive and negative ELISpot responses while properly controlling the rate of false positives is critical. In this paper, we consider several statistical methods that are helpful in defining such a positive criterion. Simulation results under a variety of scenarios suggest that a permutation-based criterion using a resampling adjustment for multiple comparisons yields the desired false positive rate while remaining competitive with other potential criteria in terms of sensitivity. These results also provide guidance on the effect of the number of experimental and negative control replicate wells on assay sensitivity. Application of different potential positive criteria using ELISpot assay results from IFN-γ-secreting T cells of HIV-1 seropositive and seronegative donors confirmed several of the results obtained under simulation. Our findings support the application of statistically-based positive criteria such as the permutation-based resampling approach in assessing HIV vaccine-induced T cell responses. Moreover, the proposed methods have potential utility in related HIV immunopathogenesis studies and in non-HIV clinical vaccine trials. [Copyright &y& Elsevier]

Different single-cell analyses for the detection of antigen-specific T cells based on antigen-triggered induction of cytokine production (elispot, intracellular cytokine staining, cytokine secretion assay, etc.) have been analyzed. In this paper we present the data of a thorough validation of the IFNγ Secretion Assay (ISA, Miltenyi Biotec, Bergisch Gladbach, Germany). In this assay the secreted IFNγ is bound to the cell surface and is then stained as an artificial surface molecule and analyzed by flow-cytometry. The introduction of five quality criteria markedly improved the reproducibility of this assay and made it very reliable (intra-assay variability<5%; inter-assay variability<20%). Recovery experiments further demonstrated that almost 100% of IFNγ+ labeled cells could be detected by this technology. In order to analyze which cell subsets contribute to IFNγ-production, we compared the results obtained in different individuals after VZAg-stimulation. Three different IFNγ-secretion patterns could be discerned. In Pattern 1 there is a predominant and almost equal contribution of T cells and NK cells with a minor contribution of CD3+CD56+ and B cells. Pattern 2, which is most abundant, is characterized by a predominance of NK cells (60–70%). Pattern 3 differs from the previous one in its minor contribution of NK cells. Here T cells predominate the IFNγ secretion. These results clearly demonstrate that the IFNγ+ subset distribution after VZAg-stimulation is not uniform and differs individually. Furthermore, the ISA-technology proves to be very useful in vaccine research. This was demonstrated by testing the IFNγ+ secretion pattern after HBsAg-stimulation in PBMC from HBsAg-vaccinated individuals. [Copyright &y& Elsevier]