B7-1 and B7-2 costimulatory molecules activate differentially the Th1/Th2 developmental pathways: application to autoimmune disease therapy

Interactions between dendritic cells and T lymphocytes in pathogenesis of nasal polyps

The aim of the present study was to investigate the functional status of dendritic cells (DCs) in nasal polyps (NP) and their interactions with T lymphocytes. The interactions between DC and T lymphocytes in the pathogenesis of NP was also studied. The expression of cluster of differentiation (CD)1a and CD83 in NP was detected using immunohistochemistry and the ratio of CD83 DC/CD1a+DC was counted. The distribution of DCs in NP and normal inferior turbinate mucosa (nITM) was evaluated using double immunostaining (CD1a/CD40) and low illumination fluorescence microscopy. The number of CD1a+ cells, CD83+ cells and CD1a/CD40-dual positive cells in was significantly higher in NP tissues compared with nITM. Furthermore, the density of DCs observed in NP was significantly greater than that observed in nITM. The ratio of CD83 DC/CD1a+DC in NP was significantly higher compared with in nITM tissues. The results of the present study revealed significant infiltration of DCs in NP, with the majority being mature DCs. DCs are able to interact with T cells via the CD40/CD40L costimulatory factor, thus serving an important role in the development and progression of NP.

Sjögren's Syndrome: Pathogenesis

Sjögren's syndrome is a chronic inflammatory disease of the lacrimal and salivary gland with subsequent keratoconjunctivitis sicca and xerostomia. Histopathologic findings include damaged acini of the lacrimal and salivary glands with mononuclear cell infiltrates of lymphocytic and plasma cell type. The cause of the damage is cell-mediated cytotoxicity. The pathogenesis of Sjögren's syndrome is still unknown. The role of viral infections failed to show a causative effect. On the other hand, tissue destruction was shown to be mediated by activated T cells of CD4+ type that home into the lacrimal gland. This process is signal-mediated through the T-cell receptor that interacts with class II antigen on the epithelial cells of exocrine glands. This, in turn, induces the expression of Fas/APO-1 and Fas-mediated apoptosis of acinar cells. Granzyme A and perforin are cytolytic enzymes secreted by activated T lymphocytes that seem to participate in acinar cell destruction.

Naegleria fowleri immunization modifies lymphocytes and APC of nasal mucosa

We investigated whether intranasal immunization with amoebic lysates plus cholera toxin modified the populations of T and B lymphocytes, macrophages and dendritic cells by flow cytometry from nose-associated lymphoid tissue (NALT), cervical lymph nodes (CN), nasal passages (NP) and spleen (SP). In all immunized groups, the percentage of CD4 was higher than CD8 cells. CD45 was increased in B cells from mice immunized. We observed IgA antibody-forming cell (IgA-AFC) response, mainly in NALT and NP. Macrophages from NP and CN expressed the highest levels of CD80 and CD86 in N. fowleri lysates with either CT or CT alone immunized mice, whereas dendritic cells expressed high levels of CD80 and CD86 in all compartment from immunized mice. These were lower than those expressed by macrophages. Only in SP from CT-immunized mice, these costimulatory molecules were increased. These results suggest that N. fowleri and CT antigens are taking by APCs, and therefore, protective immunity depends on interactions between APCs and T cells from NP and CN. Consequently, CD4 cells stimulate the differentiation from B lymphocytes to AFC IgA-positive; antibody that we previously found interacting with trophozoites in the nasal lumen avoiding the N. fowleri attachment to nasal epithelium.

Evaluation of the toxicity of iron-ion irradiation in murine bone marrow dendritic cells via increasing the expression of indoleamine 2,3-dioxygenase 1

High linear energy transfer radiation is known to deposit higher energy in tissues and cause greater toxicity compared to low-LET irradiation. Local immunosuppression is frequently observed after irradiation (IR). Dendritic cells (DCs) play important roles in the initiation and maintenance of the immune response. The dysfunction of DCs contributes to tumor evasion and growth. However, molecular mechanisms underlying the establishment of immune tolerance induced by heavy ion IR through this DC population are poorly understood. Therefore, here we report our findings on the dysfunction of bone marrow-derived dendritic cells (BMDCs) induced by 1 Gy iron ion radiation and promotions of expressions of JNK1/2/3, indoleamine 2,3-dioxygenase 1 (IDO1), p-ERK1/2 and p38/MAPK; and decrease of IDO2, MHC class II, CD40, CD80 expressions and IFN-γ and TNF-α secretion after total-body IR in mice. JNK+IDO1+ BMDCs showed up-expression of p-ERK1/2 and p-p38/MAPK, reduced expression of MHC class II and CD80, and were not able to effectively stimulate allogeneic spleen T cells. The inhibition of IDO1 expressions could partly restore the function of BMDCs. In all, our study shows that elevated JNK and IDO1 expression induced by Fe ion IR could result in dysfunction of BMDCs via p-p38/MAPK and p-ERK1/2 signal pathway, and it may represent a new mechanism in radiation-induced immune tolerance.

Qualitative differences in T-cell activation by dendritic cell-derived extracellular vesicle subtypes

Exosomes, nano-sized secreted extracellular vesicles (EVs), are actively studied for their diagnostic and therapeutic potential. In particular, exosomes secreted by dendritic cells (DCs) have been shown to carry MHC-peptide complexes allowing efficient activation of T lymphocytes, thus displaying potential as promoters of adaptive immune responses. DCs also secrete other types of EVs of different size, subcellular origin and protein composition, whose immune capacities have not been yet compared to those of exosomes. Here, we show that large EVs (lEVs) released by human DCs are as efficient as small EVs (sEVs), including exosomes, to induce CD4+ T-cell activation in vitro When released by immature DCs, however, lEVs and sEVs differ in their capacity to orient T helper (Th) cell responses, the former favouring secretion of Th2 cytokines, whereas the latter promote Th1 cytokine secretion (IFN-γ). Upon DC maturation, however, these functional differences are abolished, and all EVs become able to induce IFN-γ. Our results highlight the need to comprehensively compare the functionalities of EV subtypes in all patho/physiological systems where exosomes are claimed to perform critical roles.

Oligomeric proanthocyanidins attenuate airway inflammation in asthma by inhibiting dendritic cells maturation

To date, although a promising anti-inflammatory activity of oligomeric proanthocyanidins (OPCs) has been observed in asthma, the mechanism responsible for these immunomodulatory properties remains obscure. Dendritic cells (DCs) that reside in the airway have been widely perceived as an important contributor to asthma. Our study was to demonstrate OPCs' effects on maturation and immunoregulation of pulmonary CD11c⁺ dendritic cells (DCs). BALB/c mice were exposed to ovalbumin (OVA) to induce murine model of asthma. In addition, pulmonary DCs and bone marrow-derived DCs (BMDCs) cultures were used to evaluate impacts of OPCs on DCs function. The results obtained here indicated that OPCs treatment dramatically reduced airway inflammation, such as the infiltration of inflammatory cells and the levels of allergen-specific serum IgE and Th2 cytokines. The expression of co-stimulatory molecules especially CD86 distributed on pulmonary DCs and bone marrow-derived DCs (BMDCs) also markedly declined. The phosphorylation of cAMP responsive element-binding protein (CREB) was significantly inhibited while no changes were observed in the expression of cAMP responsive element modulator (CREM). By transferring BMDCs into the airways of naïve mice, we found that OPCs-treated DCs (DC+OVA+OPC) were much less potent in promoting CD4⁺ T cells proliferation than OVA-pulsed DCs (DC+OVA), followed by the ameliorated eosinophilic inflammation in airway. Our findings tailor a novel profile of OPCs in the regulation of DCs function, shedding new light on the therapeutic potential of OPCs in asthma management.

Monoclonal Antibodies in Preclinical EAE Models of Multiple Sclerosis: A Systematic Review

Monoclonal antibodies (mAb) are promising therapeutics in multiple sclerosis and multiple new candidates have been developed, hence increasing the need for some agreement for preclinical mAb studies. We systematically analyzed publications of experimental autoimmune encephalomyelitis (EAE) studies showing effects of monoclonal antibodies. A PubMed search retrieved 570 records, out of which 122 studies with 253 experiments were eligible based on experimental design, number of animals and presentation of time courses of EAE scores. Analysis of EAE models, treatment schedules, single and total doses, routes of administration, and onset of treatment from pre-immunization up to 35 days after immunization revealed high heterogeneity. Total doses ranged from 0.1 to 360 mg/kg for observation times of up to 35 days after immunization. About half of experiments (142/253) used total doses of 10-70 mg/kg. Employing this range, we tested anti-Itga4 as a reference mAb at varying schedules and got no, mild or substantial EAE-score reductions, depending on the mouse strain and onset of the treatment. The result agrees with the range of outcomes achieved in 10 reported anti-Itga4 experiments. Studies comparing low and high doses of various mAbs or early vs. late onset of treatment did not reveal dose-effect or timing-effect associations, with a tendency towards better outcomes with preventive treatments starting within the first week after immunization. The systematic comparison allows for extraction of some "common" design characteristics, which may be helpful to further assess the efficacy of mAbs and role of specific targets in preclinical models of multiple sclerosis.

Co-stimulatory and Co-inhibitory Pathways in Autoimmunity

The immune system is guided by a series of checks and balances, a major component of which is a large array of co-stimulatory and co-inhibitory pathways that modulate the host response. Although co-stimulation is essential for boosting and shaping the initial response following signaling through the antigen receptor, inhibitory pathways are also critical for modulating the immune response. Excessive co-stimulation and/or insufficient co-inhibition can lead to a breakdown of self-tolerance and thus to autoimmunity. In this review, we will focus on the role of co-stimulatory and co-inhibitory pathways in two systemic (systemic lupus erythematosus and rheumatoid arthritis) and two organ-specific (multiple sclerosis and type 1 diabetes) emblematic autoimmune diseases. We will also discuss how mechanistic analysis of these pathways has led to the identification of potential therapeutic targets and initiation of clinical trials for autoimmune diseases, as well as outline some of the challenges that lie ahead.

Impact of combined sodium chloride and saturated long-chain fatty acid challenge on the differentiation of T helper cells in neuroinflammation

BACKGROUND

There has been a marked increase in the incidence of autoimmune diseases like multiple sclerosis (MS) in the last decades which is most likely driven by a change in environmental factors. Here, growing evidence suggests that ingredients of a Western diet like high intake of sodium chloride (NaCl) or saturated fatty acids may impact systemic immune responses, thus increasing disease susceptibility. Recently, we have shown that high dietary salt or long-chain fatty acid (LCFA) intake indeed aggravates T helper (Th) cell responses and neuroinflammation.

METHODS

Naïve CD4⁺ T cells were treated with an excess of 40 mM NaCl and/or 250 μM lauric acid (LA) in vitro to analyze effects on Th cell differentiation, cytokine secretion, and gene expression. We employed ex vivo analyses of the model disease murine experimental autoimmune encephalomyelitis (EAE) to investigate whether salt and LCFA may affect disease severity and T cell activation in vivo.

RESULTS

LCFA, like LA, together with NaCl enhance the differentiation of Th1 and Th17 cells as well as pro-inflammatory cytokine and gene expression in vitro. In cell culture, we observed an additive effect of LA and hypertonic extracellular NaCl (NaCl + LA) in Th17 differentiation assays as well as on IL-17, GM-CSF, and IL-2 gene expression. In contrast, NaCl + LA reduced Th2 frequencies. We employed EAE as a model of Th1/Th17 cell-mediated autoimmunity and show that the combination of a NaCl- and LA-rich diet aggravated the disease course and increased T cell infiltration into the central nervous system (CNS) to the same extent as dietary NaCl.

CONCLUSIONS

Our findings demonstrate a partially additive effect of NaCl and LA on Th cell polarization in vitro and on Th cell responses in autoimmune neuroinflammation. These data may help to better understand the pathophysiology of autoimmune diseases such as MS.

Induction of Paralysis and Visual System Injury in Mice by T Cells Specific for Neuromyelitis Optica Autoantigen Aquaporin-4

While it is recognized that aquaporin-4 (AQP4)-specific T cells and antibodies participate in the pathogenesis of neuromyelitis optica (NMO), a human central nervous system (CNS) autoimmune demyelinating disease, creation of an AQP4-targeted model with both clinical and histologic manifestations of CNS autoimmunity has proven challenging. Immunization of wild-type (WT) mice with AQP4 peptides elicited T cell proliferation, although those T cells could not transfer disease to naïve recipient mice. Recently, two novel AQP4 T cell epitopes, peptide (p) 135-153 and p201-220, were identified when studying immune responses to AQP4 in AQP4-deficient (AQP4^-/-) mice, suggesting T cell reactivity to these epitopes is normally controlled by thymic negative selection. AQP4^-/- Th17 polarized T cells primed to either p135-153 or p201-220 induced paralysis in recipient WT mice, that was associated with predominantly leptomeningeal inflammation of the spinal cord and optic nerves. Inflammation surrounding optic nerves and involvement of the inner retinal layers (IRL) were manifested by changes in serial optical coherence tomography (OCT). Here, we illustrate the approaches used to create this new in vivo model of AQP4-targeted CNS autoimmunity (ATCA), which can now be employed to study mechanisms that permit development of pathogenic AQP4-specific T cells and how they may cooperate with B cells in NMO pathogenesis.

The TIM Family of Cosignaling Receptors: Emerging Targets for the Regulation of Autoimmune Disease and Transplantation Tolerance

Currently, lifelong immune suppression regimens are required for solid organ and cellular transplantation and carry significant increased risk of infection, malignancy, and toxicity. For non-life-saving procedures such as islet transplantation, the risk/benefit ratio of lifelong immunosuppression versus benefit from transplantation requires even more careful balance. The search for specific agents to modulate the immune system without chronic immunosuppression is important for the broad application of islet transplantation. The T-cell immunoglobulin mucin (TIM) family is a distinct group of coreceptors that are differentially expressed on TH1 and TH2 cells, and have the potential to regulate both cytotoxic and humoral immune responses. Completed murine studies demonstrate Tim pathways may be important in the regulation of tolerance to self (auto), harmless (allergic), and transplant (allo) antigen; however, the potential impact of targeting Tim coreceptors has yet to be fully explored in transplantation tolerance induction or autoimmune disease. The current review examines the impact of Tim coreceptor targeting as an emerging therapeutic option for regulating autoimmune diseases and prevention of allograft rejection.

Application of the adverse outcome pathway (AOP) concept to structure the available in vivo and in vitro mechanistic data for allergic sensitization to food proteins

BACKGROUND

The introduction of whole new foods in a population may lead to sensitization and food allergy. This constitutes a potential public health problem and a challenge to risk assessors and managers as the existing understanding of the pathophysiological processes and the currently available biological tools for prediction of the risk for food allergy development and the severity of the reaction are not sufficient. There is a substantial body of in vivo and in vitro data describing molecular and cellular events potentially involved in food sensitization. However, these events have not been organized in a sequence of related events that is plausible to result in sensitization, and useful to challenge current hypotheses. The aim of this manuscript was to collect and structure the current mechanistic understanding of sensitization induction to food proteins by applying the concept of adverse outcome pathway (AOP).

MAIN BODY

The proposed AOP for food sensitization is based on information on molecular and cellular mechanisms and pathways evidenced to be involved in sensitization by food and food proteins and uses the AOPs for chemical skin sensitization and respiratory sensitization induction as templates. Available mechanistic data on protein respiratory sensitization were included to fill out gaps in the understanding of how proteins may affect cells, cell-cell interactions and tissue homeostasis. Analysis revealed several key events (KE) and biomarkers that may have potential use in testing and assessment of proteins for their sensitizing potential.

CONCLUSION

The application of the AOP concept to structure mechanistic in vivo and in vitro knowledge has made it possible to identify a number of methods, each addressing a specific KE, that provide information about the food allergenic potential of new proteins. When applied in the context of an integrated strategy these methods may reduce, if not replace, current animal testing approaches. The proposed AOP will be shared at the www.aopwiki.org platform to expand the mechanistic data, improve the confidence in each of the proposed KE and key event relations (KERs), and allow for the identification of new, or refinement of established KE and KERs.

Human bronchial epithelium orchestrates dendritic cell activation in severe asthma

The innate immune response is impaired in asthma, with increased epithelial release of C-X-C motif chemokine ligand (CXCL)8, interleukin (IL)-33 and thymic stromal lymphopoietin (TSLP). We hypothesised that dendritic cells might modulate the hyperresponsive epithelium in severe asthma.

For this purpose, we investigated epithelial–dendritic crosstalk in normal and diseased conditions, and because ultrafine particulate matter may affect asthmatic airways, we investigated its impact on this crosstalk. Air–liquid interface cultures of human bronchial epithelial cells (HBEC) of control subjects (cHBEC) or severe asthma patients (saHBEC) were co-cultured with monocyte-derived dendritic cells (moDC).

Increased release of CXCL8, TSLP and IL-33 from saHBEC contrasted with cHBEC producing CXCL10 and CCL2. Regarding moDC activation, saHBEC co-cultures induced only upregulation of CD86 expression, while cHBEC yielded full moDC maturation with HLA-DR, CD80, CD86 and CD40 upregulation. Particulate matter stimulation of HBEC had no effect on cHBEC but stimulated CXCL8 and IL-33 release in saHBEC. Particulate matter impaired epithelium signalling (TSLP, IL-33 and CXCL8) in saHBEC co-cultures despite C-C chemokine ligand 2 induction.

Crosstalk between HBEC and moDC can be establishedin vitro, driving a T1-type response with cHBEC and a T2-type response with saHBEC. Normal or asthmatic status of HBEC differentially shapes the epithelial–dendritic responses. We conclude that control moDC cannot rescue the hyperresponsive airway epithelium of severe asthmatics.

Antigen presentation for priming T cells in central system

Generation of myelin antigen-specific T cells is a major event in neuroimmune responses that causes demyelination. The antigen-priming of T cells and its location is important in chronic and acute inflammation. In autoimmune multiple sclerosis, the effector T cells are considered to generate in periphery. However, the reasons for chronic relapsing-remitting events are obscure. Considering mechanisms, a feasible aim of research is to investigate the role of antigen-primed T cells in lupus cerebritis. Last thirty years of investigations emphasize the relevance of microglia and infiltrated dendritic cells/macrophages as antigen presenting cells in the central nervous system. The recent approach towards circulating B-lymphocytes is an important area in the context. Here, we analyze the existing findings on antigen presentation in the central nervous system. The aim is to visualize signaling events of myelin antigen presentation to T cells and lead to the strategy of future goals on immunotherapy research.

Role of immune tolerance in BALB/c mice with anaphylactic shock after Echinococcus granulosus infection

This study tested the hypothesis that immune tolerance mediated by regulatory T (Treg) cells is protective against cystic echinococcosis (CE)-induced anaphylactic shock. BALB/c mice were inoculated with protoscoleces of Echinococcus granulosus. After 3 months, the presence of cysts in the peritoneal cavity was confirmed after which a subset of mice was sensitized using a cyst fluid suspension to induce anaphylactic shock. While IgE levels were significantly higher in both groups inoculated with E. granulosus as compared to the healthy control group (both P < 0.01), sensitized mice had higher IgE levels as compared with those with E. granulosus alone (P < 0.05). Mice inoculated with E. granulosus alone and sensitized mice both had significantly higher histamine levels as compared to the healthy controls. The proportion of CD4(+)CD25(+)Foxp3(+) Treg cells relative to CD4(+) cells was significantly higher in mice inoculated with E. granulosus alone (P < 0.0167); significantly higher interleukin-10 (IL-10) and tumor growth factor-β (TGF-β1) levels were also noted in this group (all P < 0.01). In contrast, IL-13 and IL-17A levels were significantly higher in the sensitized mice (both P < 0.05). Taken together, these data suggest that the biphasic changes in Treg cell and cytokine levels may be associated with anaphylactic shock induced by CE.

B cells of multiple sclerosis patients induce autoreactive proinflammatory T cell responses

Antibody-independent B cell functions play an important role in multiple sclerosis (MS) pathogenesis. In this study, B cell antigen presentation and costimulation in MS were studied. Peripheral blood B cells of MS patients showed increased expression of costimulatory CD86 and CD80 molecules compared with healthy controls (HC). In MS cerebrospinal fluid (CSF), 12-fold and 2-fold increases in CD86⁺ and CD80⁺ B cells, respectively, were evidenced compared with peripheral blood. Further, B cells from MS patients induced proinflammatory T cells in response to myelin basic protein (MBP). Immunomodulatory treatment restored B cell costimulatory molecule expression and caused significantly reduced B cell induced T cell responses. Together, these results demonstrate the potential of B cells from MS patients to induce autoreactive proinflammatory T cell responses. Immunomodulatory therapy abrogated this effect, emphasizing the importance of B cell antigen presentation and costimulation in MS pathology.

Association of peripheral blood dendritic cells with recurrent pregnancy loss: a case-controlled study

PROBLEM

Dendritic cells (DCs) have been reported to play an important role in pregnancy. However, the role of DCs in recurrent pregnancy loss (RPL) has not been investigated well.

METHOD OF STUDY

Forty-three women affected by RPL and 16 fertile controls were recruited from June 2013 to December 2014. The peripheral blood DCs subsets, including myeloid DCs (mDCs) and plasmacytoid DCs (pDCs), the levels (%) of CD80(+) , CD86(+) , and CD200(+) DCs were analyzed using flow cytometry.

RESULTS

The levels of total DCs, mDCs, and CD86(+) DCs were significantly higher (all P<.05); however, the level of CD200(+) DCs in the RPL group was significantly lower than that of the control group (P<.05). The logistical regression analyses showed that the elevated level of mDCs was significantly associated with RPL after adjustment for age (OR: 1.14, 95% CI, 1.01-1.29, P<.05).

CONCLUSION

The elevated level of mDCs was significantly associated with RPL, which might lead to the intervention of targeted immunosuppression in women with RPL.

Multifaceted interactions between adaptive immunity and the central nervous system

Neuroimmunologists seek to understand the interactions between the central nervous system (CNS) and the immune system, both under homeostatic conditions and in diseases. Unanswered questions include those relating to the diversity and specificity of the meningeal T cell repertoire; the routes taken by immune cells that patrol the meninges under healthy conditions and invade the parenchyma during pathology; the opposing effects (beneficial or detrimental) of these cells on CNS function; the role of immune cells after CNS injury; and the evolutionary link between the two systems, resulting in their tight interaction and interdependence. This Review summarizes the current standing of and challenging questions related to interactions between adaptive immunity and the CNS and considers the possible directions in which these aspects of neuroimmunology will be heading over the next decade.

Adiponectin Suppresses T Helper 17 Cell Differentiation and Limits Autoimmune CNS Inflammation via the SIRT1/PPARγ/RORγt Pathway

T helper 17 (Th17) cells are vital components of the adaptive immune system involved in the pathogenesis of most autoimmune and inflammatory syndromes, and adiponectin(ADN) is correlated with inflammatory diseases such as multiple sclerosis (MS) and type II diabetes. However, the regulatory effects of adiponectin on pathogenic Th17 cell and Th17-mediated autoimmune central nervous system (CNS) inflammation are not fully understood. In this study, we demonstrated that ADN could inhibit Th1 and Th17 but not Th2 cells differentiation in vitro. In the in vivo study, we demonstrated that ADN deficiency promoted CNS inflammation and demyelination and exacerbated experimental autoimmune encephalomyelitis (EAE), an animal model of human MS. Furthermore, ADN deficiency increased the Th1 and Th17 cell cytokines of both the peripheral immune system and CNS in mice suffering from EAE. It is worth mentioning that ADN deficiency predominantly promoted the antigen-specific Th17 cells response in autoimmune encephalomyelitis. In addition, in vitro and in vivo, ADN upregulated sirtuin 1 (SIRT1) and peroxisome proliferator-activated receptor γ (PPARγ) and inhibited retinoid-related orphan receptor-γt (RORγt); the key transcription factor during Th17 cell differentiation. These results systematically uncovered the role and mechanism of adiponectin on pathogenic Th17 cells and suggested that adiponectin could inhibit Th17 cell-mediated autoimmune CNS inflammation.

Azithromycin impairs TLR7 signaling in dendritic cells and improves the severity of imiquimod-induced psoriasis-like skin inflammation in mice

BACKGROUND

The activation of Toll-like receptor 7 (TLR7) in dendritic cells (DCs) plays a crucial role in the pathogenesis of psoriasis. The macrolide antibiotic azithromycin (AZM) had been demonstrated to inhibit the TLR4 agonist-induced maturation and activation of murine bone marrow-derived DCs (BMDCs).

OBJECTIVE

To investigate the effects of AZM on the induction of DC maturation and activation by imiquimod (IMQ), a synthetic TLR7 agonist, as well as its potential as a therapeutic agent for psoriasis.

METHODS

The effects of AZM on IMQ-induced DC activation were investigated based on the expression of cell surface markers and cytokine secretion. The lysosomal pH, post-translational processing of TLR7, and TLR7 signaling were also examined in DCs. The therapeutic effects of AZM on psoriasis were evaluated in a murine model of IMQ-induced psoriasis-like skin inflammation.

RESULTS

AZM significantly inhibited the expression of co-stimulatory molecules (CD40 and CD80) and reduced TNF-α, IL-10, IL-12p40, IL-12p70, IL-23p19 in BMDCs and IFN-α production in plasmacytoid DCs. AZM treatment impaired lysosomal acidification, interrupted TLR7 maturation in the lysosome, and ultimately blocked the IMQ-induced NF-κB and IRF-7 nuclear translocation in DCs. AZM treatment decreased signs of IMQ-induced skin inflammation in BALB/c mice. In addition to decreasing keratinocyte hyper-proliferation and restoring their terminal differentiation, AZM treatment decreased the accumulation of DCs as well as CD4, CD8 T cells and IL-17 producing cells in psoriatic skin lesions. AZM treatment improved splenomegaly, decreased the populations of Th17 and γδ T cells, and reduced the expression of cytokines known to be involved in the pathogenesis of psoriasis, such as IL-17A, IL-17F, IL-22 and IL-23, in the skin and spleen.

CONCLUSION

AZM impaired IMQ-induced DC activation by decreasing lysosomal acidification and disrupting TLR7 maturation and signaling. AZM significantly improved the IMQ-induced psoriasis-like inflammation in mice. AZM may be a potential therapeutic candidate for psoriasis treatment.

Glycolysis inhibition as a cancer treatment and its role in an anti-tumour immune response

Increased glycolysis is the main source of energy supply in cancer cells that use this metabolic pathway for ATP generation. Altered energy metabolism is a biochemical fingerprint of cancer cells that represents one of the "hallmarks of cancer". The immune system can prevent tumour growth by eliminating cancer cells but this editing process ultimately results in poorly immunogenic cells remaining allowing for unchallenged tumour growth. In this review we look at the glycolysis pathway as a target for cancer treatments. We also examine the interplay between the glycolysis modulation and the immune response as an anti-cancer therapy.

Multiple sclerosis: expression of C D1a and production of IL-12 p70 and IFN-γ by blood mononuclear cells in patients on combination therapy with IFN-β and glatiramer acetate compared to monotherapy with IFN-β

Current therapy of multiple sclerosis (MS) with interferon-beta (IFN-b) or glatiramer acetate (GA) has modest effects on the course of MS. Both compounds affect several immune variables, like expression of cell surface molecules and cytokine levels. Here we compared untreated MS, therapy with IFN-b alone and combined with GA, and healthy controls (HC), regarding expression on HLA -DR+ blood mononuclear cells (MNC) of C D1a that is a cell surface molecule with capacity to present glycolipids to T cells, and of C D80 and C D86 which are costimulatory molecules that activate Th1 and Th2 responses. C ytokine production by MNC was also measured. Flow cytometry and ELISA were used. C ross-sectional comparisons revealed that untreated MS patients had higher C D1a+ HLA -DR+ MNC and lower IL-10 production compared to patients treated with IFN-b or IFN-b+G A or HC. Untreated MS patients also had higher spontaneous IFN-g and IL-12p70 production compared to MS patients treated with IFN-b+G A or HC, but not when compared to MS patients on monotherapy with IFN-b. Low C D1a+ HLA -DR+ MNC and low spontaneous production of IL-12p70 and IFN-g were more pronounced in patients treated with IFN-b+G A than with IFN-b alone. In order to clarify whether these changes reflect disease activity or treatment effects, we performed a follow up study. Nineteen MS patients with disease progression, despite monotherapy with IFN-b for more than one year, were re-examined after one to three and four to six months of treatment with IFN-b+G A. This combination therapy was associated with normalization of C D1a+ HLA -DR+ MNC, IL-12p70 and IFN-g. It remains to be shown whether these immunological changes imply a clinical benefit. Follow up studies of immune variables versus clinical effects during combined therapy of MS with IFN-b+G A are ongoing.

Curcumin ameliorates experimental autoimmune myasthenia gravis by diverse immune cells

Curcumin is a traditional Asian medicine with diverse immunomodulatory properties used therapeutically in the treatment of many autoimmune diseases. However, the effects of curcumin on myasthenia gravis (MG) remain undefined. Here we investigated the effects and potential mechanisms of curcumin in experimental autoimmune myasthenia gravis (EAMG). Our results demonstrated that curcumin ameliorated the clinical scores of EAMG, suppressed the expression of T cell co-stimulatory molecules (CD80 and CD86) and MHC class II, down-regulated the levels of pro-inflammatory cytokines (IL-17, IFN-γ and TNF-α) and up-regulated the levels of the anti-inflammatory cytokine IL-10, shifted the balance from Th1/Th17 toward Th2/Treg, and increased the numbers of NKR-P1(+) cells (natural killer cell receptor protein 1 positive cells, including NK and NKT cells). Moreover, the administration of curcumin promoted the differentiation of B cells into a subset of B10 cells, increased the anti-R97-166 peptide IgG1 levels and decreased the relative affinity indexes of anti-R97-116 peptide IgG. In summary, curcumin effectively ameliorate EAMG, indicating that curcumin may be a potential candidate therapeutic agent for MG.

Association of IL4 and IL4R polymorphisms with multiple sclerosis susceptibility in Caucasian population: A meta-analysis

BACKGROUND

Previous studies have suggested a role for interleukin-4 (IL4) and its receptor (IL4R) gene in susceptibility to multiple sclerosis (MS), but the results remain controversial and under-powered.

OBJECTIVES

To investigate the contradictory results, we performed a meta-analysis to assess the possible association between polymorphisms of the IL4 rs2243250 (C/T), variable number of tandem repeat (VNTR) polymorphism in intron-3 (I3(709)VNTR), IL4R rs1801275 (T/C) and MS in Caucasian populations.

METHODS

A comprehensive search was conducted to identify all case-control or cohort design studies. The fixed or random effect pooled measure was selected based on the homogeneity test among studies that was evaluated with I(2). Publication bias was estimated using the Begg's and Egger's test.

RESULTS

A total of ten studies were included in the meta-analysis. The crude odds ratios (ORs) with 95% confidence intervals (95% CI) were calculated to evaluate the association. Overall, after excluding articles deviating from Hardy-Weinberg equilibrium in controls and sensitive analysis, the meta-analysis showed a significant association between polymorphism of IL4 rs2243250 and MS susceptibility in allele model (OR=1.209, 95% CI=1.022-1.429, P=0.026) and dominant model (OR =1.225, 95% CI=1.013-1.480, P=0.036). However, no significant association was found between polymorphisms of IL4 I3(709)*VNTR, IL4R rs1801275 and MS susceptibility, respectively.

CONCLUSIONS

The meta-analysis indicates that the T allele, CT and TT genotype of polymorphism of IL4 rs2243250 (C/T) may reduce the risk of MS in Caucasian populations, while polymorphisms of IL4 I3(709)*VNTR and IL4R rs1801275 may not associated with risk of MS in Caucasian populations.

Dimethyl fumarate treatment induces adaptive and innate immune modulation independent of Nrf2

Dimethyl fumarate (DMF) (BG-12, Tecfidera) is a fumaric acid ester (FAE) that was advanced as a multiple sclerosis (MS) therapy largely for potential neuroprotection as it was recognized that FAEs are capable of activating the antioxidative transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway. However, DMF treatment in randomized controlled MS trials was associated with marked reductions in relapse rate and development of active brain MRI lesions, measures considered to reflect CNS inflammation. Here, we investigated the antiinflammatory contribution of Nrf2 in DMF treatment of the MS model, experimental autoimmune encephalomyelitis (EAE). C57BL/6 wild-type (WT) and Nrf2-deficient (Nrf2(-/-)) mice were immunized with myelin oligodendrocyte glycoprotein (MOG) peptide 35-55 (p35-55) for EAE induction and treated with oral DMF or vehicle daily. DMF protected WT and Nrf2(-/-) mice equally well from development of clinical and histologic EAE. The beneficial effect of DMF treatment in Nrf2(-/-) and WT mice was accompanied by reduced frequencies of IFN-γ and IL-17-producing CD4(+) cells and induction of antiinflammatory M2 (type II) monocytes. DMF also modulated B-cell MHC II expression and reduced the incidence of clinical disease in a B-cell-dependent model of spontaneous CNS autoimmunity. Our observations that oral DMF treatment promoted immune modulation and provided equal clinical benefit in acute EAE in Nrf2(-/-) and WT mice, suggest that the antiinflammatory activity of DMF in treatment of MS patients may occur through alternative pathways, independent of Nrf2.

The immune-modulatory effects of a mixed herbal formula on dendritic cells and CD4+ T lymphocytes in the treatment of dust mite allergy asthma and perennial allergic rhinitis

OBJECTIVE

Asthma and allergic rhinitis are chronic inflammatory diseases of the conducting nasal airway. Traditional Chinese medicine has long been used for supplemental therapy of allergic diseases, especially asthma and allergic rhinitis. We previously reported the effects of a mixed herbal formula in patients with allergic rhinitis. However, the immune-modulatory mechanism underlying the effects of herbal medicine for the treatment of allergic diseases remains unclear.

METHODS

We investigated the physiologic changes in dendritic cell (DC) and CD4(+) T cell activity in patients with asthma and allergic rhinitis who were treated with a mixed herbal formula composed of Xin-yi-san + Xiao-qing-long-tang + Xiang-sha-liu- jun-zi-tang. Specifically, we set up in vitro autologous or heterologous co-culture experiments between DCs and CD4(+) T cells, and used flow cytometry and ELISA to analyze the expression of surface molecules on DCs and the release of cytokines by CD4(+) T cells.

RESULTS

Expression of HLA-DR on DCs was suppressed following treatment with the mixed herbal formula. Surface expression of CD40, CD54 and CD86 on DCs was also attenuated after treatment. In autologous co-cultures, CD4(+) T cells increased their IL-10 production while decreasing TNF-α production. In heterologous co-cultures, IL-10 secretion by T cells was enhanced, while IL-12, IL-4, IL-5 and TNF-α secretion were reduced.

CONCLUSION

Our mixed herbal formula attenuated the allergic reaction by modifying the physiologic function of the DC-CD4(+) T cell interaction. Further investigations are necessary to understand the mechanism of immune modification mediated by the mixed herbal formula.

Role of CD4+ T Cells in the Pathophysiology of Multiple Sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system. Although the precise etiology of MS remains unclear, CD4⁺ T cells have been proposed to play not only effector but also regulatory roles in MS. CD4⁺ T cells can be divided into four subsets: pro-inflammatory helper T (Th) 1 and Th17 cells, anti-inflammatory Th2 cells and regulatory T cells (Tregs). The roles of CD4⁺ T cells in MS have been clarified by either “loss-of-function” or “gain-of-function” methods, which have been carried out mainly in autoimmune and viral models of MS: experimental autoimmune encephalomyelitis and Theiler's murine encephalomyelitis virus infection, respectively. Observations in MS patients were consistent with the mechanisms found in the MS models, that is, increased pro-inflammatory Th1 and Th17 activity is associated with disease exacerbation, while anti-inflammatory Th2 cells and Tregs appear to play a protective role.

Belatacept prophylaxis against organ rejection in adult kidney-transplant recipients

End-stage renal disease is a major health problem worldwide, with kidney transplantation being the treatment of choice. Calcineurin inhibitors are still the cornerstone of immunosuppressive therapy. However, they have well-known nephrotoxic affects and increase the risk of cardiovascular disease and cancer. In contrast, belatacept is a biological immunosuppressive agent that inhibits the T-cell co-stimulation. It is approved by the US Food and Drug Administration and the European Medicine Agency for use in adult kidney-transplant recipients to prevent acute rejection. Developmental studies show that belatacept is as efficient as calcineurin inhibitors at preventing acute rejection. In addition, kidney function is better and cardiovascular risk factors are reduced in patients given belatacept. Herein, the authors review the published evidence concerning the efficacy and safety of belatacept and discuss its potential specific indications.

B Cells Are Multifunctional Players in Multiple Sclerosis Pathogenesis: Insights from Therapeutic Interventions

Multiple sclerosis (MS) is a severe disease of the central nervous system (CNS) characterized by autoimmune inflammation and neurodegeneration. Historically, damage to the CNS was thought to be mediated predominantly by activated pro-inflammatory T cells. B cell involvement in the pathogenesis of MS was solely attributed to autoantibody production. The first clues for the involvement of antibody-independent B cell functions in MS pathology came from positive results in clinical trials of the B cell-depleting treatment rituximab in patients with relapsing-remitting (RR) MS. The survival of antibody-secreting plasma cells and decrease in T cell numbers indicated the importance of other B cell functions in MS such as antigen presentation, costimulation, and cytokine production. Rituximab provided us with an example of how clinical trials can lead to new research opportunities concerning B cell biology. Moreover, analysis of the antibody-independent B cell functions in MS has gained interest since these trials. Limited information is present on the effects of current immunomodulatory therapies on B cell functions, although effects of both first-line (interferon, glatiramer acetate, dimethyl fumarate, and teriflunomide), second-line (fingolimod, natalizumab), and even third-line (monoclonal antibody therapies) treatments on B cell subtype distribution, expression of functional surface markers, and secretion of different cytokines by B cells have been studied to some extent. In this review, we summarize the effects of different MS-related treatments on B cell functions that have been described up to now in order to find new research opportunities and contribute to the understanding of the pathogenesis of MS.

Treatment with cyclophosphamide supported by various dendritic cell-based vaccines induces diversification in CD4⁺ T cell response against MC38 colon carcinoma

The present study shows that an application of cyclophosphamide (CY) supported by dendritic cell (DC)-based vaccines affected differentiation of the activity of CD4⁺ T cell subpopulations accompanied by an alteration in CD8⁺ cell number. Vaccines were composed of bone marrow-derived DCs activated with tumor cell lysate (BM-DC/TAg^TNF-α) and/or genetically modified DCs of JAWS II line (JAWS II/ Neo or JAWS II/IL-2 cells). Compared to untreated or CY-treated mice, the combined treatment of MC38 colon carcinoma-bearing mice resulted in significant tumor growth inhibition associated with an increase in influx of CD4⁺ and CD8⁺ T cells into tumor tissue. Whereas, the division of these cell population in spleen was not observed. Depending on the nature of DC-based vaccines and number of their applications, both tumor infiltrating cells and spleen cells were able to produce various amount of IFN-γ, IL-4 and IL-10 after mitogenic ex vivo stimulation. The administration of CY followed by BM-DC/TAg^TNF-α and genetically modified JAWS II cells, increased the percentage of CD4⁺T-bet⁺ and CD4⁺GATA3⁺ cells and decreased the percentage of CD4⁺RORγt⁺ and CD4⁺FoxP3⁺ lymphocytes. However, the most intensive response against tumor was noted after the ternary treatment with CY + BM-DC/TAg^TNF-α + JAWS II/IL-2 cells. Thus, the administration of various DC-based vaccines was responsible for generation of the diversified antitumor response. These findings demonstrate that the determination of the size of particular CD4⁺ T cell subpopulations may become a prognostic factor and be the basis for future development of anticancer therapy.

Sexual activity modulates shifts in TH1/TH2 cytokine profile across the menstrual cycle: an observational study

OBJECTIVE

To investigate if sexual activity moderated menstrual cycle-related shifts in cytokines associated with T-helper type 1 (TH1) cells (e.g., interferon [IFN] γ) and T-helper type 2 (TH2) cells (e.g., interleukin [IL] 4). Immune activity shifts across the menstrual cycle, with higher follicular-phase TH1-cell activity but higher luteal-phase TH2-cell activity. Little is known about how social behaviors alter TH1-TH2 ratios, despite evidence that psychosocial factors can influence immunity. Of particular interest is how sexual activity influences immune responses that may support conception, such as the TH1-TH2 balance.

DESIGN

Participants provided saliva samples at four time points (menstrual, follicular, ovulatory, and luteal phases), which were assayed by means of ELISA.

SETTING

Academic laboratory.

PARTICIPANT(S)

Thirty healthy premenopausal women (16 sexually abstinent, 14 sexually active) not taking hormonal or immunoactive medications.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Salivary E2, P, IFN-γ, and IL-4.

RESULT(S)

Sexually active, but not abstinent, women were significantly more likely to express TH2-like cytokine ratios (IFN-γ < IL-4) in the luteal phase than in other phases. Similarly, sexually active women had significantly higher P, and higher P-E2 ratios, in the luteal phase than did abstinent women. The P-E2 ratio mediated menstrual variations in cytokine ratios in sexually active women.

CONCLUSION(S)

These results support the hypothesis that shifts in immune response across the menstrual cycle may reflect tradeoffs between reproduction and immunity. These findings point to the need for further research on the interaction between sexual behavior, the menstrual cycle, and immune response.

Association analysis of -416 G>C polymorphism of T-cell immunoglobulin and mucin domain-1 gene with asthma in Iran

TIM (T-cell immunoglobulin (Ig) and mucin domain)-1, one of the members of TIM family, expresses on Th2 cells and promotes the production of Th2 signature cytokines. This can increase a series of responses in these cells which could be one of the causes of asthma or asthma-related phenotypes. The aim of this study was to investigate whether a TIM-1 promoter single nucleotide polymorphism (SNP), -416 G>C, is associated with asthma in Iranian population. In this case-control study, existence of the -416 G>C polymorphism was assessed using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) in 300 patients with asthma (97 atopic, 203 nonatopic) and 309 healthy volunteers. Additionally, the relationship between these polymorphism genotypes and total serum IgE levels in this Iranian population was evaluated. We discovered a significant association between the -416 G>C polymorphism and atopic asthma susceptibility in the population, but this SNP showed no connection with nonatopic asthma (P < 0.05). However, our results showed significant relation between this polymorphism and serum IgE level (P < 0.05). Our results suggest that -416 G>C polymorphism in TIM-1 gene could be a predisposing factor for atopic asthma in Iranian population, and CC genotype of this SNP can be associated with increased level of IgE in patients with asthma in the same population.

A novel recombinant BCG-expressing pro-apoptotic protein BAX enhances Th1 protective immune responses in mice

One-third of the world's population is infected with Mycobacterium tuberculosis (MTB). The protective efficacy of bacille Calmette Guérin (BCG) vaccine against tuberculosis (TB) in adults is highly controversial even though the BCG vaccine has been available for more than 90 years. Because BCG is effective against infantile tuberculosis meningitis and miliary tuberculosis in young children and provides cost-effective prevention from tuberculosis for developing countries, it would be desirable to modify the existing BCG vaccine to provide more comprehensive protection. In our study, we constructed a novel recombinant BCG strain expressing pro-apoptotic BAX (rBCG::BAX) and demonstrated that it significantly induced the apoptosis of macrophages infected with rBCG::BAX both in vitro and in vivo. In addition, it significantly enhanced Ag85B-specific IFN-γ enzyme-linked immunospot responses, IFN-γ secretion, IL-2 secretion and the ratio of Ag85B-specific IgG2b/IgG1, and it significantly decreased Ag85B-specific IL-4. Furthermore, it presumably facilitated antigen presentation by inducing a significant up-regulation in the expression of MHC-II and B7.1 (CD80) co-stimulatory molecules on macrophages. In conclusion, these results suggest that the rBCG::BAX strain elicited predominantly a Th1 protective immune responses and might be a potential tuberculosis vaccine candidate for further study.

DC type 2 polarization depends on both the allergic status of the individual and protease activity of Per a 10

Cockroach proteases are important risk factors for asthma development in predisposed individuals. In the present study, effect of allergic status of patients on DCs polarization in response to protease allergen Per a 10 was investigated. Cockroach-allergic, other-allergic patients and healthy individuals were selected following the guidelines of ATS/ARIA. Monocyte-derived dendritic cells (DCs) were generated from the selected individuals and stimulated with Per a 10. Flow cytometric analysis showed a significantly high expression of CD80 and CD86 on DCs from cockroach-allergic patients after Per a 10 stimulation as compared to healthy individuals or other-allergic patients (P<0.05). Per a 10 induced comparable level of CD83 expression on DCs from all the 3 groups, showing it was irrespective of the allergic status. CD40 expression was significantly low (P<0.05) on the DCs from cockroach-allergic patients as compared to healthy individuals or other-allergic patients. Further, proteolytically active Per a 10 induced lower CD40 expression on DCs than the heat-inactivated Per a 10 (P<0.05) indicating role of protease activity in the generation of an immune response. The sCD40 level in active Per a 10 stimulated DC cultures was significantly higher than in heat-inactivated Per a 10 (P<0.05). There was two-fold decrease (P<0.05) in IL-12 production by active Per a 10-stimulated DCs than heat-inactivated Per a 10-stimulated DCs. Per a 10-stimulated DCs from cockroach-allergic patients secreted high levels of IL-5, IL-6, TNF-α than that from healthy individuals or other-allergic patients (P<0.05). Furthermore, Per a 10-stimulated DCs from cockroach-allergic patients induced increased secretions of IL-4, IL-5, IL-6, TNF-α and low IL-12 by T cells as compared to those from other groups (P<0.05). Thus, in presence of Per a 10 allergen, polarization of DCs shifts toward type 2 in cockroach-allergic patients but not in the healthy individuals or other-allergic patients. In conclusion, both allergic status of the individual and protease activity of Per a 10 are important parameters that participate in DCs polarization.

Dendritic cell interactions with Histoplasma and Paracoccidioides

Fungi are among the most common microbes encountered by humans. More than 100, 000 fungal species have been described in the environment to date, however only a few species cause disease in humans. Fungal infections are of particular importance to immunocompromised hosts in whom disease is often more severe, especially in those with impaired cell-mediated immunity such as individuals with HIV infection, hematologic malignancies, or those receiving TNF-α inhibitors. Nevertheless, environmental disturbances through natural processes or as a consequence of deforestation or construction can expose immunologically competent people to a large number of fungal spores resulting in asymptomatic acquisition to life-threatening disease. In recent decades, the significance of the innate immune system and more importantly the role of dendritic cells (DC) have been found to play a fundamental role in the resolution of fungal infections, such as in dimorphic fungi like Histoplasma and Paracoccidioides. In this review article the general role of DCs will be illustrated as the bridge between the innate and adaptive immune systems, as well as their specific interactions with these 2 dimorphic fungi.

The effects of radio-frequency electromagnetic fields on T cell function during development

With the widespread use of radio-frequency devices, it is increasingly important to understand the biological effects of the associated electromagnetic fields. Thus, we investigated the effects of radio-frequency electromagnetic fields (RF-EMF) on T cell responses during development due to the lack of science-based evidence for RF-EMF effects on developmental immune systems. Sprague Dawley (SD) rats were exposed to 2.14-GHz wideband code division multiple-access (W-CDMA) RF signals at a whole-body specific absorption rate (SAR) of 0.2 W/kg. Exposures were performed for a total of 9 weeks spanning in utero development, lactation and the juvenile period. Rats were continuously exposed to RF-EMF for 20 h/day, 7 days/week. Comparisons of control and exposed rats using flow cytometry revealed no changes in the numbers of CD4/CD8 T cells, activated T cells or regulatory T cells among peripheral blood cells, splenocytes and thymocytes. Expression levels of 16 genes that regulate the immunological Th1/Th2 paradigm were analyzed using real-time PCR in the spleen and thymus tissues of control and RF-EMF-exposed rats. Although only the Il5 gene was significantly regulated in spleen tissues, Il4, Il5 and Il23a genes were significantly upregulated in thymus tissues following exposure to RF-EMF. However, ELISAs showed no changes in serum IL-4 protein concentrations. These data indicate no adverse effects of long-term RF-EMF exposure on immune-like T cell populations, T cell activation, or Th1/Th2 balance in developing rats, although significant transcriptional effects were observed.

Nicotine exposure alters the mRNA expression of Notch ligands in dendritic cells and their response to Th1-/Th2-promoting stimuli

Dendritic cells (DCs) utilize polarizing signals to instruct the differentiation of T helper (Th) cells into Th1 and Th2 effector cells: antigen-specific 'signal 1', costimulatory 'signal 2' and polarizing cytokines 'signal 3'. Accumulating evidence suggests the involvement of an additional signal, the Notch signalling pathway. We reported that in response to Th1-promoting stimuli, both mouse and human DCs generated in the presence of the immune modulator nicotine (nicDCs) fail to support the development of effector memory Th1 cells. However, in response to Th2-promoting stimuli, these nicDCs preferentially support the differentiation of antigen-specific IL-4-producing Th2 effector cells. Here, we show that when compared to their control counterparts, immature mouse and human nicDCs display higher levels of the Notch ligands D1, D4 and J2 mRNA expression. In response to Th1- and Th2-promoting stimuli, mouse nicDCs display higher levels of the Notch ligands D1, D4 and J2, while human nicDCs show higher levels of D1, D4 and J1 mRNA expression. Furthermore, both stimulated mouse and human nicDCs express higher CD86 to CD80 ratio and produce lower amount of IL-12. Collectively, our data suggest that these changes in addition to an increase in Jagged expression correlate with the ability of nicDCs to modulate the Th1/Th2 balance in favour of Th2 generation.

The influence of Ouabain on human dendritic cells maturation

Although known as a Na,K-ATPase inhibitor, several other cellular and systemic actions have been ascribed to the steroid Ouabain (Oua). Particularly in the immune system, our group showed that Ouabain acts on decreasing lymphocyte proliferation, synergizing with glucocorticoids in spontaneous thymocyte apoptosis, and also lessening CD14 expression and blocking CD16 upregulation on human monocytes. However, Ouabain effects on dendritic cells (DCs) were not explored so far. Considering the peculiar plasticity and the importance of DCs in immune responses, the aim of our study was to investigate DC maturation under Ouabain influence. To generate immature DCs, human monocytes were cultured with IL-4 and GM-CSF (5 days). To investigate Ouabain role on DC activation, DCs were stimulated with TNF-α for 48 h in the presence or absence of Ouabain. TNF-induced CD83 expression and IL-12 production were abolished in DCs incubated with 100 nM Ouabain, though DC functional capacity concerning lymphocyte activation remained unaltered. Nevertheless, TNF-α-induced antigen capture downregulation, another maturation marker, occurred even in the presence of Ouabain. Besides, Ouabain increased HLA-DR and CD86 expression, whereas CD80 expression was maintained. Collectively, our results suggest that DCs respond to Ouabain maturating into a distinct category, possibly contributing to the balance between immunity and tolerance.

Lactosucrose attenuates intestinal inflammation by promoting Th2 cytokine production and enhancing CD86 expression in colitic rats

Some oligosaccharides have immunoregulatory and anti-inflammatory functions in the intestine. This study investigated the immunoregulatory effect of lactosucrose (LS) on 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitic rats. Alkaline phosphatase activity was increased but myeloperoxidase activity was decreased in the LS-TNBS group, as compared with the TNBS group (colitis rats without receiving LS). LS supplementation stimulated IL-4 and IL-10 production, while up-regulating CD86 expression in dendritic cells. LS supplementation reduced the ratio of CD80/CD86 and the ratio of IFN-γ/IL-4 compared to the TNBS group. Moreover, IFN-γ was significantly correlated with CD80 (r = 0.764, p < 0.01), whereas IL-4 was significantly correlated with CD86 (r = 0.489, p < 0.05). These results indicated that LS attenuated colitis by promoting the production of Th2-type cytokines and rebalancing the ratio of Th1/Th2 and that enhanced IL-4 production is correlated with enhanced CD86 expression in the gut. Therefore, LS is a functional food for patients with inflammatory bowel disease.

Decreased Dicer expression is linked to increased expression of co-stimulatory molecule CD80 on B cells in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is an immune-mediated inflammatory disease of the central nervous system. B cells have been strongly implicated in disease pathogenesis based on clinical trials with B-cell ablation. There is a growing body of evidence linking microRNAs with regulation of the immune system. Dicer, a key enzyme involved in microRNA biogenesis, is necessary for normal B-cell function.

OBJECTIVE

We aimed to determine whether Dicer expression is impaired in B cells and is linked to increased expression co-stimulatory molecules in patients with MS.

METHODS

B cells were separated from blood samples of MS patients and healthy subjects. Expression of Dicer and co-stimulatory molecules CD80 and CD86 was tested. The effect of Dicer modulation on CD80 and CD86 expression in B cells was studied.

RESULTS

Dicer expression was decreased in B cells but not in monocytes of patients with MS compared with healthy subjects. CD80 and CD86 expression was increased on B cells of MS patients compared with healthy subjects. Inhibition of Dicer expression in B cells by small interfering RNA led to increased expression of CD80.

CONCLUSION

Dicer expression is decreased and is mechanistically linked to increased expression of co-stimulatory molecule CD80 in B cells of patients with MS. This may contribute to activation of immune responses in MS.

Immunomodulation of human intestinal T cells by the synthetic CD80 antagonist RhuDex®

Deregulated activation of mucosal lamina propria T cells plays a central role in the pathogenesis of intestinal inflammation. One of the means to attenuate T cell activation is by blocking the CD28/CD80 co-stimulatory pathway. Here we investigate RhuDex®, a small molecule that binds to human CD80, for its effects on the activation of lamina propria T cells employing a gut-culture model of inflammation. To this end, lamina propria leukocytes (LPL) and peripheral blood lymphocytes (PBL) were stimulated either through the CD3/T-cell-receptor complex or the CD2-receptor (CD2) employing agonistic monoclonal antibodies. Co-stimulatory signals were provided by CD80/CD86 present on lamina propria myeloid cells or LPS-activated peripheral blood monocytes. Results show that RhuDex® caused a profound reduction of LPL and PBL proliferation, while Abatacept (CTLA-4-Ig) inhibited LPL proliferation to a small degree, and had no effect on PBL proliferation. Furthermore, Abatacept significantly inhibited IL-2, TNF-α, and IFN-γ release from LPL, primarily produced by CD4⁺ T cells, where IL-2 blockage was surprisingly strong, suggesting a down-regulating effect on regulatory T cells. In contrast, in the presence of RhuDex®, secretion of IL-17, again mostly by CD4⁺ T cells, and IFN-γ was inhibited in LPL and PBL, yet IL-2 remained unaffected. Thus, RhuDex® efficiently inhibited lamina propria and peripheral blood T-cell activation in this pre-clinical study making it a promising drug candidate for the treatment of intestinal inflammation.

T cell subsets and their signature cytokines in autoimmune and inflammatory diseases

CD4(+) T helper (Th) cells are critical for proper immune cell homeostasis and host defense, but are also major contributors to pathology of autoimmune and inflammatory diseases. Since the discovery of the Th1/Th2 dichotomy, many additional Th subsets were discovered, each with a unique cytokine profile, functional properties, and presumed role in autoimmune tissue pathology. This includes Th1, Th2, Th17, Th22, Th9, and Treg cells which are characterized by specific cytokine profiles. Cytokines produced by these Th subsets play a critical role in immune cell differentiation, effector subset commitment, and in directing the effector response. Cytokines are often categorized into proinflammatory and anti-inflammatory cytokines and linked to Th subsets expressing them. This article reviews the different Th subsets in terms of cytokine profiles, how these cytokines influence and shape the immune response, and their relative roles in promoting pathology in autoimmune and inflammatory diseases. Furthermore, we will discuss whether Th cell pathogenicity can be defined solely based on their cytokine profiles and whether rigid definition of a Th cell subset by its cytokine profile is helpful.

Small interfering RNA against CD86 during allergen challenge blocks experimental allergic asthma

Background

CD86-CD28 interaction has been suggested as the principal costimulatory pathway for the activation and differentiation of naïve T cells in allergic inflammation. However, it remains uncertain whether this pathway also has an essential role in the effector phase. We sought to determine the contribution of CD86 on dendritic cells in the reactivation of allergen-specific Th2 cells.

Methods

We investigated the effects of the downregulation of CD86 by short interfering RNAs (siRNAs) on Th2 cytokine production in the effector phase in vitro and on asthma phenotypes in ovalbumin (OVA)-sensitized and -challenged mice.

Results

Treatment of bone marrow-derived dendritic cells (BMDCs) with CD86 siRNA attenuated LPS-induced upregulation of CD86. CD86 siRNA treatment impaired BMDCs’ ability to activate OVA-specific Th2 cells. Intratracheal administration of CD86 siRNA during OVA challenge downregulated CD86 expression in the airway mucosa. CD86 siRNA treatment ameliorated OVA-induced airway eosinophilia, airway hyperresponsiveness, and the elevations of OVA-specific IgE in the sera and IL-5, IL-13, and CCL17 in the bronchoalveolar lavage fluid, but not the goblet cell hyperplasia.

Conclusion

These results suggest that local administration of CD86 siRNA during the effector phase ameliorates lines of asthma phenotypes. Targeting airway dendritic cells with siRNA suppresses airway inflammation and hyperresponsiveness in an experimental model of allergic asthma.

Immunological effects of methylprednisolone pulse treatment in progressive multiple sclerosis

OBJECTIVE

To investigate the effect of monthly oral methylprednisolone pulse treatment in progressive MS.

METHODS

30 progressive MS patients were treated with oral methylprednisolone every month. Peripheral blood mononuclear cells were analyzed by flow cytometry.

RESULTS

Out of 102 leukocyte phenotypes investigated, 25 changed at nominal significance from baseline to week 12 (p<0.05). After correction for multiple comparisons, we found 5 subpopulations that changed compared to baseline. No pattern were suggesting modulation of Th17 or TFH cells.

CONCLUSION

Methylprednisolone pulse treatment has some effects on circulating immune cells but does not modulate markers of Th17 and TFH cell activity in progressive MS.

B cell subsets and dysfunction of regulatory B cells in IgG4-related diseases and primary Sjögren's syndrome: the similarities and differences

Introduction

IgG4-related disease (IgG4-RD) is a multisystem-involved autoimmune disease. Abnormally activated and differentiated B cells may play important roles. Regulatory B cells (Breg) are newly defined B cell subgroups with immunosuppressive functions. In this study, we investigated the differences of B cell subsets, the expressions of co-stimulatory molecules on B cells, and the function of Breg cells in patients with IgG4-RD, primary Sjögren’s syndrome (pSS) as well as in healthy controls (HC).

Methods

Newly diagnosed IgG4-RD patients (n = 48) were enrolled, 38 untreated pSS patients and 30 healthy volunteers were recruited as disease and healthy controls. To analyze B cell subsets and B cell activity, PBMCs were surface stained and detected by flow cytometry. The function of Breg cells was tested by coculturing isolated CD19 + CD24^hiCD38^hi Breg cells with purified CD4 + CD25- T cells. Serum cytokines were measured by ELISA and cytometric bead array. Relationship between clinical data and laboratory findings were analyzed as well.

Results

Compared with pSS patients and HC, IgG4-RD patients had a lower frequency of peripheral Breg cells. Interestingly, CD19 + CD24-CD38^hi B cell subsets were significantly higher in peripheral B cells from IgG4-RD patients than in pSS patients and HC, which correlated with serum IgG4 levels. The expression of BAFF-R and CD40 on B cells was significantly lower in IgG4-RD patients compared with those in pSS patients and HC. Unlike HC, Breg cells from pSS patients lacked suppressive functions.

Conclusions

B cells in patients with IgG4-RD and pSS display a variety of abnormalities, including disturbed B cell subpopulations, abnormal expression of key signaling molecules, co-stimulatory molecules, and inflammatory cytokines. In addition, a significantly increased B cell subset, CD19 + CD24-CD38^hi B cells, may play an important role in the pathogenesis of IgG4-RD.