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Corticosteroids have been utilised in the assisted reproduction setting with the expectation of suppressing aberrant immune activation and improving fertility in women. However, the effects of corticosteroids on fertility, and on pregnancy and offspring outcomes, are unclear. In this study, mice were administered prednisolone (1 mg/kg) or PBS daily in the pre-implantation phase, and effects on the adaptive immune response, the implantation rate, fetal development and postnatal outcomes were investigated. Prednisolone disrupted the expected expansion of CD4+ T cells in early pregnancy, inhibiting generation of both regulatory T cells (Treg cells) and effector T cells and suppressing IFNG required for T cell functional competence. Prednisolone caused an 8–20% increase in the embryo implantation rate and increased the number of viable pups per litter. In late gestation, fetal and placental weights were reduced in a litter size-dependent manner, and the canonical inverse relationship between litter size and fetal weight was lost. The duration of pregnancy was extended by ~ 0.5 day and birth weight was reduced by ~ 5% after prednisolone treatment. Viability of prednisolone-exposed offspring was comparable to controls, but body weight was altered in adulthood, particularly in male offspring. Thus, while prednisolone given in the pre-implantation phase in mice increases maternal receptivity to implantation and resource investment in fetal growth, there is a trade-off in long-term consequences for fetal development, birth weight and offspring health. These effects are associated with, and likely caused by, prednisolone suppression of the adaptive immune response at the outset of pregnancy.

Introduction: Microbial infection and associated super antigens have been implicated in the pathogenesis of cutaneous T-cell lymphoma (CTCL), and many patients die from complicating bacterial infections. It has been postulated that Chlamydophila pneumoniae (C. pneumoniae) infection may be involved in the pathogenesis of Mycosis fungoides (MF) but published data are limited and controversial. Aim: To analyze the frequency of (C. pneumoniae) DNA presence in blood samples of lymphoma cases. Material and methods: Using Q-PCR method we analyzed the presence of DNA in the blood samples obtained from 57 patients with CTCL (55 - mycosis fungoides (MF)/Sezary syndrome (SS), one primary cutaneous anaplastic large cell lymphoma (CD30+) and one NKT cell lymphoma) and 3 patients with cutaneous B-cell lymphomas, and 120 individuals from control groups (40 patients with psoriasis, 40 patients with atopic dermatitis and 40 healthy controls). Results: Chlamydophila pneumoniae DNA was identified in 13 of 55 cases in the MF/SS group (23.6%), in 1 patient with CD30+ large cell lymphoma and in 1 of 3 patients with B-cell lymphoma. The presence of C. pneumoniae was confirmed in 1 of 40 psoriatic patients (2.5%), in 5 of 40 patients with atopic dermatitis (12.5%) and in none of 40 healthy individuals. Presence of C. pneumoniae DNA in MF patients was strongly associated with disease progression; rs = 0.756; p = 0.0123 for groups IA -> IVB, and was noted more frequently in advanced (III + IV) stages than in early (I-II) stages (p = 0.0139). There are no differences in the mean age of MF/SS patients with and without infection. Conclusions: The presence of C. pneumoniae DNA in the blood cells is a frequent event in late stages of MF/SS and may be explained by Th2 shift and suppression of the immune system during the course of the disease.

Contains fulltext : 172589.pdf (Publisher’s version ) (Closed access) Despite the importance of immune variation for the symptoms and outcome of Lyme disease, the factors influencing cytokine production during infection with the causal pathogen Borrelia burgdorferi remain poorly understood. Borrelia infection-induced monocyte- and T cell-derived cytokines were profiled in peripheral blood from two healthy human cohorts of Western Europeans from the Human Functional Genomics Project. Both non-genetic and genetic host factors were found to influence Borrelia-induced cytokine responses. Age strongly impaired IL-22 responses, and genetic studies identified several independent QTLs that impact Borrelia-induced cytokine production. Genetic, transcriptomic, and functional validation studies revealed an important role for HIF-1alpha-mediated glycolysis in the cytokine response to Borrelia. HIF-1alpha pathway activation and increase in glycolysis-derived lactate was confirmed in Lyme disease patients. In conclusion, functional genomics approaches reveal the architecture of cytokine production induced by Borrelia infection of human primary leukocytes and suggest a connection between cellular glucose metabolism and Borrelia-induced cytokine production.

BACKGROUND: Heterologous prime-boost vaccination with chimpanzee adenovirus 63 (ChAd63) and modified vaccinia virus Ankara (MVA) encoding multiple epitope string thrombospondin-related adhesion protein (ME-TRAP) has shown acceptable safety and promising immunogenicity in African adult and pediatric populations. If licensed, this vaccine could be given to infants receiving routine childhood immunizations. We therefore evaluated responses to ChAd63 MVA ME-TRAP when co-administered with routine Expanded Program on Immunization (EPI) vaccines. METHODS: We enrolled 65 Gambian infants and neonates, aged 16, 8, or 1 week at first vaccination and randomized them to receive either ME-TRAP and EPI vaccines or EPI vaccines only. Safety was assessed by the description of vaccine-related adverse events (AEs). Immunogenicity was evaluated using IFNγ enzyme-linked immunospot, whole-blood flow cytometry, and anti-TRAP IgG ELISA. Serology was performed to confirm all infants achieved protective titers to EPI vaccines. RESULTS: The vaccines were well tolerated in all age groups with no vaccine-related serious AEs. High-level TRAP-specific IgG and T cell responses were generated after boosting with MVA. CD8+ T cell responses, previously found to correlate with protection, were induced in all groups. Antibody responses to EPI vaccines were not altered significantly. CONCLUSION: Malaria vectored prime-boost vaccines co-administered with routine childhood immunizations were well tolerated. Potent humoral and cellular immunity induced by ChAd63 MVA ME-TRAP did not reduce the immunogenicity of co-administered EPI vaccines, supporting further evaluation of this regimen in infant populations. CLINICAL TRIAL REGISTRATION: The clinical trial was registered on http://Clinicaltrials.gov (NCT02083887) and the Pan-African Clinical Trials Registry (PACTR201402000749217).

Background Asthma exacerbations represent a significant disease burden and are commonly caused by rhinovirus (RV), which is sensed by Toll-like receptors (TLR) such as TLR7. Some asthmatics have impaired interferon (IFN) responses to RV, but the underlying mechanisms of this clinically relevant observation are poorly understood. Objectives To investigate the importance of intact TLR7 signalling in vivo during RV exacerbation using mouse models of house dust mite (HDM)-induced allergic airways disease exacerbated by a superimposed RV infection. Methods Wild-type and TLR7-deficient ( Tlr7 −/− ) BALB/c mice were intranasally sensitised and challenged with HDM prior to infection with RV1B. In some experiments, mice were administered recombinant IFN or adoptively transferred with plasmacytoid dendritic cells (pDC). Results Allergic Tlr7 −/− mice displayed impaired IFN release upon RV1B infection, increased virus replication and exaggerated eosinophilic inflammation and airways hyper reactivity. Treatment with exogenous IFN or adoptive transfer of TLR7-competent pDCs blocked these exaggerated inflammatory responses and boosted IFNγ release in the absence of host TLR7 signalling. TLR7 expression in the lungs was suppressed by allergic inflammation and by interleukin (IL)-5-induced eosinophilia in the absence of allergy. Subjects with moderate-to-severe asthma and eosinophilic but not neutrophilic airways inflammation, despite inhaled steroids, showed reduced TLR7 and IFNλ2/3 expression in endobronchial biopsies. Furthermore, TLR7 expression inversely correlated with percentage of sputum eosinophils. Conclusions This implicates IL-5-induced airways eosinophilia as a negative regulator of TLR7 expression and antiviral responses, which provides a molecular mechanism underpinning the effect of eosinophil-targeting treatments for the prevention of asthma exacerbations.

The protozoan parasite Trypanosoma cruzi circulates in the blood upon infection and invades various cells. Parasites intensively multiply during the acute phase of infection and persist lifelong at low levels in tissues and blood during the chronic phase. Natural killer (NK) and NKT cells play an important role in the immune control of T. cruzi infection, mainly by releasing the cytokine IFN-γ that activates the microbicidal action of macrophages and other cells and shapes a protective type 1 immune response. The mechanisms by which immune cells are regulated to produce IFN-γ during T. cruzi infection are still incompletely understood. Here, we show that urokinase plasminogen activator (uPA) is induced early upon T. cruzi infection and remains elevated until day 20 post-infection. We previously demonstrated that the inhibitory receptor Ly49E, which is expressed, among others, on NK and NKT cells, is triggered by uPA. Therefore, we compared wild type (WT) to Ly49E knockout (KO) mice for their control of experimental T. cruzi infection. Our results show that young, i.e., 4- and 6-week-old, Ly49E KO mice control the infection better than WT mice, indicated by a lower parasite load and less cachexia. The beneficial effect of Ly49E depletion is more obvious in 4-week-old male than in female mice and weakens in 8-week-old mice. In young mice, the lower T. cruzi parasitemia in Ly49E KO mice is paralleled by higher IFN-γ production compared to their WT controls. Our data indicate that Ly49E receptor expression inhibits the immune control of T. cruzi infection. This is the first demonstration that the inhibitory Ly49E receptor can interfere with the immune response to a pathogen in vivo. ispartof: Frontiers in Immunology vol:7 issue:NOV ispartof: location:Switzerland status: published

Aims Foxo3 is a transcription factor involved in cell metabolism, survival, and inflammatory disease. However, mechanistic insight in Foxo3 effects is still limited. Here, we investigated the role of Foxo3 on natural killer (NK) cell responses and its effects in viral myocarditis. Methods and results Effects of Foxo3 on viral load and immune responses were investigated in a model of coxsackie virus B3 myocarditis in wild-type (WT) and Foxo3 deficient mice. Reduced immune cell infiltration, viral titres, and pro-inflammatory cytokines in cardiac tissue were observed in Foxo3(-/-) mice 7 days post-infection (p.i.). Viral titres were also attenuated in hearts of Foxo3(-/-) mice at Day 3 while interferon-gamma (IFN gamma) and NKp46 expression were up-regulated suggesting early viral control by enhanced NK cell activity. CD69 expression of NK cells, frequencies of CD11b(+)CD27(+) effector NK cells and cytotoxicity of Foxo3(-/-) mice was enhanced compared to WT littermates. Moreover, microRNA-155 expression, essential in NK cell activation, was elevated in Foxo3(-/-) NK cells while its inhibition led to diminished IFN gamma production. Healthy humans carrying the longevity-associated FOXO3 single nucleotide polymorphism (SNP) rs12212067 exhibited reduced IFN gamma and cytotoxic degranulation of NK cells. Viral inflammatory cardiomyopathy (viral CMI) patients with this SNP showed a poorer outcome due to less efficient virus control. Conclusion Our results implicate Foxo3 in regulating NK cell function and suggest Foxo3 playing an important role in the antiviral innate immunity. Thus, enhanced FOXO3 activity such as in the polymorphism rs12212067 may be protective in chronic inflammation such as cancer and cardiovascular disease but disadvantageous to control acute viral infection.

In order to get more insight into the role of neutrophils on the micro-environment and consequently on macrophages in the foreign body reaction in mice, we investigated the fate of the two differently crosslinked dermal sheep collagen disks (glutaraldehyde = GDSC, hexamethylenediisocyanate = HDSC) in mice implanted in one anatomical location, namely subcutaneously. In GDSC massive infiltration of neutrophils is seen at day 2 and day 21, whereas in HDSC only minor infiltration is seen at day 2. The presence of neutrophils coincided with high levels of IFN-gamma, a cytokine that activates macrophages. Major differences were seen in degradation rate of the two disks: GDSC was almost completely degraded after 28 days, whereas HDSC remained intact. Degradation of GDSC occurred through collagenolytic activity and phagocytosis by macrophages. Phagocytosis was observed at day 2 and day 21. IL-13 was only observed in HDSC, and this resulted in the presence of giant cells in HDSC. These giant cells produced IL-10, that promoted TIMP-1 expression and that inhibits collagenolytic and phagocytic activity. We conclude that the function of macrophages in mice is largely influenced by differences in micro-environment induced by GDSC and HDSC and that the presence/absence of neutrophils play a major role in the shaping of this micro-environment. (C) 2010 Elsevier Ltd. All rights reserved.

Several genes encoding for different cytokines may play crucial roles in host susceptibility to Brucellosis, since the cytokine production capacity varies among individuals and depends on the cytokine gene polymorphism. The association of the cytokine gene polymorphisms with the development of Brucellosis was investigated in this study. DNA samples were obtained from a Turkish population of 40 patients with Brucellosis, and 50 healthy control subjects. All genotyping (IL-6, IL10, IFN-gamma, TGF-beta and TNF-alpha) experiments were performed using sequence-specific primers PCR (PCR-SSP). When compared to the healthy controls, the frequencies of high/intermediate producing genotypes of IL-10 and high producing genotype of IL-6 were significantly more common in the patient group. These results suggest that IL-10 and IL-6 gene polymorphisms may affect susceptibility to Brucellosis and increase risk of developing the disease. In order to confirm the biological significance of our results, further studies should be performed in larger population groups. (c) 2007 Published by Elsevier Ltd.

Immunoregulatory receptors are categorized as stimulatory or inhibitory based on their engagement of unique intracellular signaling networks. These proteins also display functional plasticity, which adds versatility to the control of innate immunity. Here we demonstrate that an inhibitory catfish leukocyte immune-type receptor (IpLITR) also displays stimulatory capabilities in a representative myeloid cell model. Previously, the receptor IpLITR 1.1b was shown to inhibit natural killer cell-mediated cytotoxicity. Here we expressed IpLITR 1.1b in rat basophilic leukemia-2H3 cells and monitored intracellular signaling and functional responses. Although IpLITR 1.1b did not stimulate cytokine secretion, activation of this receptor unexpectedly induced phagocytosis as well as extracellular signal-related kinase 1/2- and protein kinase B (Akt)-dependent signal transduction. This novel IpLITR 1.1b-mediated response was independent of an association with the FcRγ chain and was likely due to phosphotyrosine-dependent adaptors associating with prototypical signaling motifs within the distal region of its cytoplasmic tail. Furthermore, compared to a stimulatory IpLITR, IpLITR 1.1b displayed temporal differences in the induction of intracellular signaling, and IpLITR 1.1b-mediated phagocytosis had reduced sensitivity to EDTA and cytochalasin D. Overall, this is the first demonstration of functional plasticity for teleost LITRs, a process likely important for the fine-tuning of conserved innate defenses.

The transcription factor GATA-3 is essential for early T cell development and differentiation of naive CD4(+) T cells into Th2 effector calls. To study the function of GATA-3 during T cell-mediated immune responses in vivo, we investigated CD2-GATA3-transgenic mice in which GATA-3 expression is driven by the CD2 locus control region. Both in the CD4(+) and the CD8(+) T cell population the proportion of cells exhibiting a CD44(high)CD45RB(low)CD62L(low) Ag-experienced phenotype was increased. In CD2-GATA3-transgenic mice, large fractions of peripheral CD4(+) T cells expressed the IL-1 receptor family member T1/ST2, indicative of advanced Th2 commitment. Upon in vitro T call stimulation, the ability to produce IL-2 and IFN-gamma was decreased. Moreover, CD4(+) T cells manifested rapid secretion of the Th2 cytokines IL-4, IL-5, and IEL-10, reminiscent of Th2 memory cells. In contrast to wild-type CD4(+) cells, which lost GATA-3 expression when cultured under Th1-polarizing conditions, CD2-GATA3-transgenic CD4(+) cells maintained expression of GATA-3 protein. Under Th1 conditions, cellular proliferation of CD2-GATA3-transgenic CD4(+) cells was severely hampered, IFN-gamma production was decreased and Th2 cytokine production was increased. Enforced GATA-3 expression inhibited Thl-mediated in vivo responses, such as Ag-specific IgG2a production or a delayed-type hypersensitivity response to keyhole limpet hemocyanin. Collectively, these observations indicate that enforced GATA-3 expression selectively inhibits Th1 differentiation and induces Th2 differentiation. The increased functional capacity to secrete Th2 cytokines, along with the increased expression of surface markers for Ag-experienced Th2-committed cells, would argue for a role of GATA-3 in Th2 memory formation.

SummaryNatural killer (NK) cells have antitumor, antiviral, and antibacterial functions, and efforts are being made to manipulate them in immunotherapeutic approaches. However, their activation mechanisms remain poorly defined, particularly during bacterial infections. Here, we show that upon lipopolysaccharide or E. coli exposure, dendritic cells (DCs) produce three cytokines—interleukin 2 (IL-2), IL-18, and interferon β (IFN-β)—necessary and sufficient for NK cell activation. IFN-β enhances NK cell activation by inducing IL-15 and IL-15 receptor α not only in DCs but, surprisingly, also in NK cells. This process allows the transfer of IL-15 on NK cell surface and its cis presentation. cis-presented NK cell-derived and trans-presented DC-derived IL-15 contribute equally to optimal NK cell activation.

International audience; L-Arginine (L-Arg) availability is crucial in the regulation of immune response. Indeed, L-Arg deficiency induces T-cell dysfunction and could modulate the properties of natural killer (NK) cells involved in the early host defense against infections and tumors. We explored the impact of L-Arg depletion on NK cell functions using two models - an NK-92 cell line and isolated human blood NK cells. Below 5 mg/L of L-Arg, NK-92 cell proliferation was decreased and a total L-Arg depletion reduced NK-92 cell viability. NK cell cytotoxicity was significantly inhibited in presence of low L-Arg concentration (2.5 mg/L). L-Arg depletion reduced the expression of NK-92 activating receptors, NKp46 and NKp30, the expression of NK zeta chain and the NK-92 intracellular production of IFN-gamma. Whatever the L-Arg concentrations tested, no significant variation in the gene expression of transporters and enzymes involved in L-Arg metabolism was found. Thus, L-Arg availability modulates the phenotypic and functional properties of NK cells.

Objective Growth arrest and DNA damage–inducible protein 45β (GADD45β) is involved in stress responses, cell cycle regulation, and oncogenesis. Previous studies demonstrated that GADD45β deficiency exacerbates K/BxN serum–induced arthritis and experimental allergic encephalomyelitis (EAE) in mice, indicating that GADD45β plays a suppressive role in innate and adaptive immune responses. To further understand how GADD45β regulates autoimmunity, we evaluated collagen-induced arthritis in GADD45β–/– mice. Methods Wild-type (WT) and GADD45β–/– DBA/1 mice were immunized with bovine type II collagen (CII). Serum anticollagen antibody levels were quantified by enzyme-linked immunosorbent assay. Expression of cytokines and matrix metalloproteinases in the joint and spleen was determined by quantitative polymerase chain reaction. The in vitro T cell cytokine response to CII was measured by multiplex analysis. CD4+CD25+ Treg cells and Th17 cells were quantified using flow cytometry. Results GADD45β–/– mice showed significantly lower arthritis severity and joint destruction compared with WT mice. MMP-3 and MMP-13 expression was also markedly reduced in GADD45β–/– mice. However, serum anti-CII antibody levels were similar in both groups. FoxP3 and interleukin-10 (IL-10) expression was increased 2–3-fold in splenocytes from arthritic GADD45β–/– mice compared with those from WT mice. Flow cytometric analysis showed greater numbers of CD4+CD25+ Treg cells in the spleen of GADD45β–/– mice than in the spleen of WT mice. In vitro studies showed that interferon-γ and IL-17 production by T cells was significantly decreased in GADD45β–/– mice. Conclusion Unlike passive K/BxN arthritis and EAE, GADD45β deficiency in CIA was associated with lower arthritis severity, elevated IL-10 expression, decreased IL-17 production, and increased numbers of Treg cells. The data suggest that GADD45β plays a complex role in regulating adaptive immunity and, depending on the model, either enhances or suppresses inflammation.

The transcription factor GATA-3 is essential for early T cell development and differentiation of naive CD4(+) T cells into Th2 effector cells. To study the function of GATA-3 during T cell-mediated immune responses in vivo, we investigated CD2-GATA3-transgenic mice in which GATA-3 expression is driven by the CD2 locus control region. Both in the CD4(+) and the CD8(+) T cell population the proportion of cells exhibiting a CD44(high)CD45RB(low)CD62L(low) Ag-experienced phenotype was increased. In CD2-GATA3-transgenic mice, large fractions of peripheral CD4(+) T cells expressed the IL-1 receptor family member T1/ST2, indicative of advanced Th2 commitment. Upon in vitro T cell stimulation, the ability to produce IL-2 and IFN-gamma was decreased. Moreover, CD4(+) T cells manifested rapid secretion of the Th2 cytokines IL-4, IL-5, and IL-10, reminiscent of Th2 memory cells. In contrast to wild-type CD4(+) cells, which lost GATA-3 expression when cultured under Th1-polarizing conditions, CD2-GATA3-transgenic CD4(+) cells maintained expression of GATA-3 protein. Under Th1 conditions, cellular proliferation of CD2-GATA3-transgenic CD4(+) cells was severely hampered, IFN-gamma production was decreased and Th2 cytokine production was increased. Enforced GATA-3 expression inhibited Th1-mediated in vivo responses, such as Ag-specific IgG2a production or a delayed-type hypersensitivity response to keyhole limpet hemocyanin. Collectively, these observations indicate that enforced GATA-3 expression selectively inhibits Th1 differentiation and induces Th2 differentiation. The increased functional capacity to secrete Th2 cytokines, along with the increased expression of surface markers for Ag-experienced Th2-committed cells, would argue for a role of GATA-3 in Th2 memory formation.