Increased Th1 Responses Research Articles

Respiratory Syncytial Virus exacerbates acute lung damage during ovalbumin-induced asthmatic inflammation

Abstract With more than 235 million people affected, asthma is the most common chronic disease in the world. In addition, respiratory viral infections, particularly respiratory syncytial virus (RSV) infection, has been associated with asthma development and significant exacerbation of asthmatic symptoms. While there are several theories exploring the causal role of RSV infection in asthma development, the pathogenic mechanism underlying the effect of RSV on asthma exacerbation remains to be understood. In this study, we investigated the effects of RSV infection on airway immune responses and lung damage in ovalbumin (OVA)-induced asthmatic mice. We found that RSV infection exacerbates acute lung damage in asthmatic mice, as indicated by their significantly increased protein and LDH levels in the airway. Although asthma is considered an allergic disease with increased Th2 responses, the levels of IL-4 and IL-5, as well as eosinophil recruitment, were unaffected in OVA-induced asthmatic mice with or without RSV super-infection. Moreover, pro-inflammatory responses, such as TNF-alpha, KC and MIP-2 production, and neutrophil infiltration, were also comparable between RSV-infected asthmatic mice and controls that only received RSV infection. Interestingly, the number of resident alveolar macrophages significantly decreased in RSV-infected asthmatic mice, as compared with RSV-infected non-asthmatic and uninfected asthmatic controls. Considering the crucial role of alveolar macrophages in resolution of airway inflammation, our future studies will determine whether RSV impairs alveolar macrophage self-maintenance, thereby prolonging airway inflammation and exacerbating lung damage during asthma.

Transcription factor p73 regulates Th1 differentiation

Inter-individual differences in T helper (Th) cell responses affect susceptibility to infectious, allergic and autoimmune diseases. To identify factors contributing to these response differences, here we analyze in vitro differentiated Th1 cells from 16 inbred mouse strains. Haplotype-based computational genetic analysis indicates that the p53 family protein, p73, affects Th1 differentiation. In cells differentiated under Th1 conditions in vitro, p73 negatively regulates IFNγ production. p73 binds within, or upstream of, and modulates the expression of Th1 differentiation-related genes such as Ifng and Il12rb2. Furthermore, in mouse experimental autoimmune encephalitis, p73-deficient mice have increased IFNγ production and less disease severity, whereas in an adoptive transfer model of inflammatory bowel disease, transfer of p73-deficient naïve CD4+ T cells increases Th1 responses and augments disease severity. Our results thus identify p73 as a negative regulator of the Th1 immune response, suggesting that p73 dysregulation may contribute to susceptibility to autoimmune disease.

2221. Chlamydia pneumoniae (Cpn) Induces IFN-γ Responses in Peripheral Blood Mononuclear Cells (PBMC) from Pediatric and Adult Asthma Patients: Effects of Age and Inhaled Corticosteroid Use

BackgroundChlamydia pneumoniae (Cpn) is unique in its ability to cause chronic infections, potentially triggering asthma exacerbations as well as subsequent asthma development. Th1-mediated immunity and IFN-γ are critical for clearing chlamydial infections. Persistent or recent Cpn infection may be identified in vitro by detecting T-helper cytokine IFN-γ produced by peripheral blood mononuclear cells (PBMC) stimulated by Cpn. Inhaled corticosteroids (ICS) may have an inhibitory effect on IFN-γ. Prior studies have shown increased Th2 responses upon in vitro Cpn stimulation with increased age. Our aim was to determine whether age and inhaled corticosteroid (ICS) use affect Cpn-induced PBMC produced IFN-γ levels.MethodsPediatric and adult subjects with (n = 23) and without (n = 10) asthma were enrolled. PBMC obtained from all subjects were stimulated with Cpn (MOI = 0.1 x48h) in vitro. IFN-γ levels in culture supernatants were determined by ELISA and reported as pg/mL. Nasopharyngeal (NP) swabs were tested for Cpn using Real-Time PCR. Statistical analysis for continuous variables was performed using the Mann–Whitney U test.ResultsNone of the subjects were positive for Cpn by PCR on NP swab. Levels of IFN-γ produced by PBMC stimulated by Cpn were similar between asthmatic vs. control subjects (41.7 vs. 68.8, respectively; P = 0.72) and between pediatric and adult subjects with asthma (IFN-γ 54 vs. 20.1 respectively, P = 0.95). Pediatric subjects with asthma who received ICS had lower IFN-γ levels than those who did not (median IFN-γ 25.5 vs. 209; P = 0.003).ConclusionOur finding of lower IFN-γ levels among asthma patients on ICS compared with those not on ICS suggests that ICS use may dampen the systemic inflammatory response. While we did not find a statistically significant difference between pediatric and adult age groups in this pilot study, there was a trend to higher Cpn-induced IFN-γ levels among younger pediatric subjects. Future prospective studies should further define predictors of diminished IFN-γ responses in patients with asthma.Disclosures All authors: No reported disclosures.

Lithraea caustic (Litre) Extract Promotes an Antitumor Response Against B16 Melanoma

Melanoma immunotherapy, specifically the autotransplant of dendritic cells charged with tumors antigens, has shown promising results in clinical trials. The positive clinical effects of this therapy have been associated to increased Th17 response and delayed-type hypersensitivity (DTH) against to tumor antigens. Some synthetic compounds, such as diphenylcyclopropenone (DPCP), are capable of triggering a DTH response in cutaneous malignancies and also to induce clinically relevant effects against melanoma. In this work, we evaluated Litre extract (LExT), a standardized extract of a Chilean stinging plant, Lithraea caustic (Litre). As Litre plant is known to induce DTH, we used a murine B16 melanoma model to compare the topical and intratumor efficacy of LExT with synthetic DTH inducers (DPCP and 2,4-dinitrochlorobenzene [DNCB]). LExt contained mainly long chain catechols and sesquiterpenes. The intratumor injection of LExT induced a significant delay in tumor growth, similarly topical treatment of an established tumor with 0.1% LExT ointment induced a growth delay and even tumor regression in 15% of treated animals. No significant changes were observed on the T-cell populations associated to LExT treatment, and neither DNCB nor DPCP were capable to induce none of the LExT-induced antitumoral effects. Interestingly, our results indicate that LExT induces an antitumor response against melanoma in a mouse model and could bring a new –and affordable- treatment for melanoma in humans.

Vitamin D enhances responses to interferon-β in MS

ObjectiveTo determine the effect of vitamin D3 on interferon-β (IFN-β) response and immune regulation in MS mononuclear cells (MNCs).MethodsMNCs from 126 subjects, including therapy-naive patients with different forms of MS, plus patients with MS receiving IFN-β or glatiramer treatment, plus healthy controls were incubated in vitro with IFN-β-1b ± vitamin D3 (calcitriol). Activation of the IFN-β–induced transcription factor, p-Y-STAT1, and antiviral myxovirus A (MxA) protein was measured with flow cytometry and Western blots; serum proteins were measured with a customized 31-protein multiplex assay.ResultsVitamin D enhanced in vitro IFN responses, as measured by induction of p-Y-STAT1 and MxA in MNCs, T cells, and monocytes. Vitamin D augmentation of IFN responses was seen in untreated and in IFN-β-1b–treated MS. The combination of vitamin D plus IFN-β reduced Th1 and Th17 cytokines, and increased Th2 responses, reversing the effect of IFN-β alone. Exacerbations and progression in untreated patients reduced the vitamin D enhancement of IFN responses. Vitamin D had less effect on IFN response in clinically stable glatiramer-treated than in IFN-β–treated patients.ConclusionVitamin D enhances IFN-β induction of multiple proteins and also reverses the Th1/Th2 bias in MS seen with IFN-β alone. The combination of vitamin D and IFN-β has potential benefit in ameliorating MS.

Lymph node segregation for tolerance or inflammation

Lymph node segregation for tolerance or inflammation

TLR4 abrogates Th1 immune response against L. infantum infection through IRF1 and IFN-β-dependent mechanism preventing immunopathology

Abstract Toll-like receptors (TLRs) are thought to be among the most ancient pathogen recognition systems, and these receptors directly interact with Leishmania species during the initial sensing of these parasites and mount the subsequent adaptive immune response. Herein, we aimed to evaluate the role of TLR4 during visceral leishmaniasis (VL) induced by Leishmania infantum. Initially, we observed that tlr4 messenger RNA (mRNA) expression was detected only the later stage of infection in target organs of VL, suggesting that TLR4 contributes significantly during the chronic phases of the disease. We have shown that Tlr4-deficient mice harbor fewer parasites in the spleen and liver than wild-type mice. TLR4 deficiency enhanced the Th1 immune response against the parasite, correlating with the increased activation of dendritic cells (DCs). Transcription analysis demonstrated that IRF1 and IFN-β are downstream of TLR4 after infection. Accordingly, IRF1- and IFNAR-genetically deficient mice harbored fewer parasites in the target organs than wild-type mice due to the increased Th1 response. The absence of TLR4 or IFNAR increases the serum transaminase level of infected mice. In addition, IFN-β acts directly on Th1 cells to limit IFN-γ production, without affecting the cell proliferation. Importantly, TLR4 and type I IFN (IFN-I) were positively modulated in asymptomatic subjects compared to VL patients. Thus, the TLR4-IRF1 pathway culminates in IFN-β production as a mechanism for dampening the chronic inflammatory process and preventing immunopathology development.

Antibiotic-Induced Disruption of Gut Microbiota Alters Local Metabolomes and Immune Responses.

Gut microbiome plays an essential role in modulating host immune responses. However, little is known about the interaction of microbiota, their metabolites and relevant inflammatory responses in the gut. By treating the mice with three different antibiotics (enrofloxacin, vancomycin, and polymixin B sulfate), we aimed to investigate the effects of different antibiotics exposure on gut microbiota, microbial metabolism, inflammation responses in the gut, and most importantly, pinpoint the underlying interactions between them. Although the administration of different antibiotics can lead to different effects on mouse models, the treatment did not affect the average body weight of the mice. A heavier caecum was observed in vancomycin treated mice. Treatment by these three antibiotics significantly up-regulated gene expression of various cytokines in the colon. Enrofloxacin treated mice seemed to have an increased Th1 response in the colon. However, such a difference was not found in mice treated by vancomycin or polymixin B sulfate. Vancomycin treatment induced significant changes in bacterial composition at phylum and family level and decreased richness and diversity at species level. Enrofloxacin treatment only induced changes in composition at family presenting as an increase in Prevotellaceae and Rikenellaceae and a decrease in Bacteroidaceae. However, no significant difference was observed after polymixin B sulfate treatment. When compared with the control group, significant metabolic shift was found in the enrofloxacin and vancomycin treated group. The metabolic changes mainly occurred in Valine, leucine, and isoleucine biosynthesis pathway and beta-Alanine metabolism in enrofloxacin treated group. For vancomycin treatment metabolic changes were mainly found in beta-Alanine metabolism and Alanine, aspartate and glutamate metabolism pathway. Moreover, modifications observed in the microbiota compositions were correlated with the metabolite concentrations. For example, concentration of pentadecanoic acid was positively correlated with richness of Rikenellaceae and Prevotellaceae and negatively correlated with Enterobacteriaceae. This study suggests that the antibiotic-induced changes in gut microbiota might contribute to the inflammation responses through the alternation of metabolic status, providing a novel insight regarding a complex network that integrates the different interactions between gut microbiota, metabolic functions, and immune responses in host.

Altered Th17/Treg Ratio in Peripheral Blood of Systemic Lupus Erythematosus but Not Primary Antiphospholipid Syndrome.

Introduction: The role of the immune response in the pathogenesis of antiphospholipid syndrome (APS) remains elusive. It is possible that differences in the frequencies of Th17 cells and/or defects in the immunoregulatory mechanisms are involved in the pathogenesis of APS. Our aim was to determine the peripheral blood Th cells phenotype and the circulating cytokine profile in patients with primary APS (pAPS) and compare it with systemic lupus erythemathosus (SLE) as disease control group.Methods: The frequencies of circulating regulatory T cells (Tregs) were determined in PBMCs from 36 patients with pAPS by flow cytometry. As control groups we included 21 age- and gender-matched healthy controls (HC) and 11 patients with SLE. The suppressive capacity of Tregs was evaluated in vitro by coculture assay. On the other hand, intracellular cytokine production was assessed in Th1, Th2, and Th17 cells and circulating IL-6, IL-10, and IL-35 were measured by Cytometric Bead Array and ELISA. The quantification of Th master gene expression levels was performed by real time quantitative PCR.Results: pAPS patients and SLE patients did not show differences in the percentage or number of Tregs compared to HC. The suppressive capacity of Tregs was also similar in the three study group. Instead, we found higher FoxP3·mRNA expression levels in pAPS patients and HC than SLE patients. Regarding the Th17 response, patients with pAPS and HC showed a significantly lower frequency of circulating Th17 cells than SLE. However, no differences were observed in the Th1 response between patients and controls. Thus, increased Th17/Th1 and Th17/Treg ratios were found in SLE patients but not in pAPS patients. pAPS and SLE patients had higher serum IL-6 levels than HC but there was not difference between both disease groups. Besides, a significant increase in the immunosuppressive cytokine levels was observed only in pAPS as compared to HC.Conclusions: Our data demonstrate an increased inflammatory profile of peripheral blood CD4+ T cells from SLE as compared with pAPS mostly due to an increased Th17 response. In conclusion, there seems not to be a direct pathogenic role for Th cells in pAPS but in SLE.

Inflammatory cytokines and change of Th1/Th2 balance as prognostic indicators for hepatocellular carcinoma in patients treated with transarterial chemoembolization

Tumor-associated immune response plays a critical role in cancer pathogenesis. This study evaluated clinical implications of T cell cytokines and regulatory T cells (Tregs) in HCC patients treated with TACE. Whole blood was obtained for analysis of T cell cytokines (IL-1β, IL-2, IL-4, IL-5, IL-6, IL-9, IL-10, IL-12p70, IL-13, IL-17A, IL-22, IFN-γ, and TNF-α) and Tregs from 142 HCC patients. Patients with CTP class A had a significantly lower proportion of detectable IL-4 or IL-6, but a higher proportion of detectable IL-22 than patients with CTP class B/C. IL-6 level was well correlated with tumor stage and undetectable IL-17A was associated with extrahepatic metastasis. The overall survival rate was significantly higher in patients who had undetectable IL-6 or detectable IL-22 than patients who did not. IL-6 among cytokines remained independently predictive factor for survival. Increased IFN-γ/IL-10 ratio and no increase in IL-6 level following TACE were associated with prolonged survival, and baseline Tregs could affect Th1/Th2 balance. T cell cytokines are associated with a variety of clinical aspects of HCC, and IL-6 is the most significant predictor of survival. A shift toward increased Th1 response and no increase in IL-6 level exert favorable immunologic effects on HCC prognosis.

A retrospective study of changes of histopathology of nasal polyps in adult Chinese in central China.

The factors contributing to the eosinophilic inflammation in chronic rhinosinusitis with nasal polyps (CRSwNP) remain elusive. This study was designed to investigate the inflammatory patterns and tissue remodeling of CRSwNP in patients from central China at two time points over 14 years apart and the influence of age. One hundred and eight CRSwNP patients enrolled in 2000 and 2001 (group A), and 134 CRSwNP patients enrolled in 2014 and 2015 (group B) were retrospectively studied. Hematoxylin-eosin stained tissue sections were used to study characteristics of inflammation and tissue remodeling. Immunohistochemistry was used to further evaluate the cells positive for eosinophil cationic protein (ECP), IL-5, IgE, tryptase or myeloperoxidase (MPO). Time- and age-related difference was analyzed. The number of eosinophils and proportion of eosinophilic CRSwNP were increased, whereas the numbers of total inflammatory cells and lymphocytes were decreased in group B as compared with group A. Group B had severer epithelial squamous metaplasia and basement membrane thickening, and a lower number of mucosal glands than group A. Higher numbers of ECP plus, IL-5 plus and IgE plus cells were detected in group B than those in group A. The elderly (60 yrs or older) and non-elderly (less than 60 yrs) had a comparable number of eosinophils and ratio of eosinophilic CRSwNP. Eosinophilic inflammation has been significantly augmented over time, which is associated with increased Th2 response and IgE production, and accompanied by exaggerated epithelium remodeling in CRSwNP patients from central China. Age has no significant influence on eosinophilic inflammation.

The Protective Effects of 2,3,5,4'-Tetrahydroxystilbene-2-O-β-d-Glucoside in the OVA-Induced Asthma Mice Model.

Asthma is an inflammatory disease caused by an imbalance of Th1 and Th2 cells. In general, asthma is characterized by a stronger Th2 response. Most conventional asthma treatment focuses on improving airway flow or suppression of airway inflammation. To reduce the side effects of currently used asthma medicines, we have conducted studies on natural products that have no side effects. 2,3,5,4′-tetrahydroxystilbene-2-O-β-d-glucoside (TSG), the main compound of Polygonum multiflorum (PM), has various biological activities, including anti-inflammation and anti-oxidation activities. However, the effect of TSG on asthma has not been studied yet. We examined the effects of TSG on Th2 immune responses using an OVA-induced asthma animal model. OVA-sensitized mice were treated with TSG. 24 h after the last intranasal challenge, airway hyperresponsiveness (AHR) was measured or serum and bronchoalveolar lavage fluid (BALF) were harvested. We measured typical Th1 and Th2 cytokines in serum and BALF. As a result, TSG suppressed Th2 responses, as shown by the lower levels of IL-4, IL-5, total IgE, OVA-specific IgE, and OVA-specific IgG1. On the other hand, TSG increased Th1 responses, as shown by the levels of IFN-gamma. Collectively, these results confirm the potential of TSG for asthma treatment through modulation of inflammatory responses. Considering that the cytotoxic effect of PM extract is due to the cis isomer of TSG, if the effect of TSG on asthma treatment is found to be non-toxic in clinical trials, it would be more effective to use it as a purified component than PM extract as an asthma treatment agent.

Immunotherapy of alveolar echinococcosis via PD-1/PD-L1 immune checkpoint blockade in mice.

SummaryThe growth potential of the tumour‐like Echinococcus multilocularis metacestode (causing alveolar echinococcosis, AE) is directly dependent upon the nature/function of the periparasitic adaptive host immune‐mediated processes. PD‐1/PD‐L1 pathway (programmed cell death 1), which inhibits lymphocytic proliferation in tumour development, is over‐expressed at the chronic stage of AE. We tested the impact of a PD‐1/PD‐L1 pathway blockade on the outcome of both chronic AE (intraperitoneal metacestode inoculation, secondary AE and SAE) and acute AE (peroral egg infection, primary AE and PAE). To assess the parasite proliferation potential, we measured parasite mass weight for SAE and liver lesion number for PAE. In both models, the parasite load was significantly decreased in response to anti‐PD‐L1 antibody treatment. In SAE, anti‐PDL1 administration was associated with increased Th1 response parameters and decreased Treg responses, while in PAE anti‐PDL1 administration was associated with fewer lesions in the liver and decreased Treg/Th2 responses. Our findings highly suggested that a PD‐1/PD‐L1 pathway blockade triggered the host immune responses in favour of an immune‐mediated control of E. multilocularis proliferation. Based on this, future studies that combine PD‐1/PD‐L1 blockade with a parasitostatic albendazole medication may yield in a putatively curative therapeutic approach to control alveolar echinococcosis.

Development of a new live attenuated Leishmania major p27 gene knockout: Safety and immunogenicity evaluation in BALB/c mice

Genetically modifying Leishmania major by eliminating essential virulence genes have been proposed as potential vaccine candidates. p27 is a COX component that is responsible for ATP synthesis. In this study a new mutant of Leishmania major (L. major) (MRHO/IR/75/ER) lacking the p27 gene (Lmp27−/−) was produced via homologous recombination, marking the first time such a strain has been developed. In vitro macrophage infectivity and In vivo safety, and overall immunogenicity were evaluated at various time periods following inoculation into BALB/c mice. Skin lesion development, parasite burden in the liver and spleen, cytokine and antibody levels, splenocyte proliferation, and delayed type hypersensitivity (DTH) were the measured variables. Results demonstrated that the Lmp27−/− mutant caused no skin lesion, had low parasitic burdens in the liver and spleen, and had a significantly increased Th1 response. These results suggest that the Lmp27−/− mutant has the potential to be evaluated as a vaccine candidate.

Th1/Th2 Imbalance and Early Age to Transplantation is Associated to Atopic Dermatitis in Heart-Transplanted Pediatric Patients

Introduction Heart transplantation is a successful strategy for the treatment of end-stage pediatric heart diseases. In recent years, improved therapies and clinical practice have led to increased graft survival, and consequently, chronic complications secondary to organ transplantation due in part to long-term immunosuppression have also emerged. Allergies and atopic diseases, such as atopic dermatitis (AD) are among these chronic complications. Despite that AD constitutes a frequent comorbidity in pediatric heart transplantation, little is known about the immune dysregulation underlying AD. Therefore, our objective was to unravel the immune mechanisms leading to AD in order to improve the clinical management of this disease in heart-transplanted children. Material and Methods We performed an extensive immune analysis comparing the values of different immune subsets (eosinophils, basophils, monocytes, T and B cells) but also their phenotype (naïve, memory, effector, activated) in peripheral blood from 11 AD heart-transplanted children and 11 age-matched non-AD heart-transplanted controls. Results/Discussion Interestingly, we observed that AD development was restricted to male children, and most of the patients in AD group were transplanted under 1 year of age (Figure 1). Heart-transplanted children with AD showed increased frequencies and absolute counts of eosinophil and plasmablasts. We also found a higher frequency of IL-4-secreting CD4+ T cells in the AD group that could represent an increased Th2 response in these patients (Figure 2). Values of Treg cells were comparable between non-AD children and AD children. However, while the non-AD group showed a clear negative correlation between Treg counts and the frequency of IL-4-secreting CD4+ T cells (Figure 3A), this association was lost in AD patients (Figure 3B), which could represent an inadequate Treg-mediated control of the effector CD4+ T-cell expansion. Conclusion The early age at transplantation and the use of immunosuppressors are critical factors that could disturb the immune homeostasis in a period that is crucial for the correct maturation of the immune system. This immune dysregulation could produce an imbalance in the Th1/Th2 immune responses, predisposing transplanted infants to AD. As a potential mechanism of this fact, the immune dysregulation may result in an impairment of Treg capacity to control IL-4-secreting CD4+ T cell expansion, which could lead to an activation of the Th2 responses in AD heart-transplanted infants.Grant from Instituto de Salud Carlos III (ISCIII) co-financed by FEDER funds (ICI14/00282). Grant from Instituto de Salud Carlos III (ISCIII) co-financed by FEDER funds (PI15/00011). Pre-doctoral grant for J.L-A from IISGM.

BMT procedure alters the functions of dendritic cells and subsequently causes pathogenic Th responses to gammaherpesvirus infection

Abstract Hematopoietic stem cell transplantation is a standard of care for many patients with genetic disorders, autoimmune diseases and malignancies. However, stem cell recipients are often more susceptible to microbial infections even after full hematopoietic reconstitution. We have previously demonstrated that syngeneic bone marrow transplantation (syn-BMT) in mice causes increased Th17 response and decreased Th1 response to murine gamma herpesvirus MHV-68 infection leading to pulmonary fibrosis. In this study, we found that Notch2-dependent conventional dendritic cells (DCs), i.e., a set of CD11b+ DCs, are required for the Th17 response to MHV-68 infection in BMT mice, while Batf3-dependent CD103+ DCs suppress the Th17 response. Furthermore, CD11b+ DCs in BMT lungs are hyper-activated with high expression of CD80 and CD86. When co-cultured with CD4+ T cells, DCs from BMT lungs promote higher productions of both IL-17A and IFN-γ than DCs from non-BMT mice, and addition of antibodies against CD80 and CD86 abolish the productions of both IL-17 and IFN-γ. Although the DCs in the BMT lungs are potent in inducing both Th1 and Th17 responses ex vivo, they are impaired in migrating into the lung draining lymph nodes (dLNs). Surprisingly, migration of DCs into the dLNs is not required for Th17 priming, since transplanting CCR7−/− bone marrow, which gives rise to non-migrating DCs in the recipient mice, does not prevent the Th17 response, but does abolish the Th1 response, suggesting a role for peripheral priming of the Th17 response in the lung post-BMT. In summary, syn-BMT causes a hyper-activated phenotype of CD11b+ DCs that promotes a pathogenic Th17 response and also causes dysfunction in DC trafficking that is required for a maximum Th1 response.

Early-life exposure to three size-fractionated ultrafine and fine atmospheric particulates in Beijing exacerbates asthma development in mature mice

BackgroundEpidemiological studies have suggested that elevated levels of air pollution contribute to an increased incidence or severity of asthma. Although late-onset adult asthma seems to be more attributable to environmental risk factors, limited data is available on the impact of early-life exposure to size-fractionated ambient particulate matter (PM) on asthma in adults. We aimed to determine the effect on the development and exacerbation of asthma in the adult after the mice were exposed as juveniles to three size-fractionated ambient particulates collected from Beijing.MethodsThe three size-fractionated ambient particulates were collected from urban Beijing in winter, heavily affected by traffic and coal-fired emissions. The typical morphological and major chemical components of the PM were characterized first. Oxidative stress and expression of DNA methyltransferases (DNMTs) were then examined in vitro and in the lungs of mouse pups 48 h after exposure to PM by oropharyngeal aspiration. When the exposed and control juvenile mice matured to adulthood, an antigen-induced asthma model was established and relevant bio-indices were assessed.ResultsPM with different granularities can induce oxidative stress; in particular, F1, with the smallest size (< 0.49 μm), decreased the mRNA expression of DNMTs in vitro and in vivo the most significantly. In an asthma model of adult mice, previous exposure as juveniles to size-fractionated PM caused increased peribronchiolar inflammation, increased airway mucus secretion, and increased production of Th2 cytokines and chemokines. In general, F1 and F2 (aerodynamic diameter < 0.95 μm) particulates affected murine adult asthma development more seriously than F3 (0.95–1.5 μm). Moreover, F1 led to airway inflammation in the form of both increased neutrophils and eosinophils in BALF. The activation of the TGF-β1/Smad2 and Smad3/Stat3 signaling pathways leading to airway fibrosis was more profoundly induced by F1.ConclusionThis study demonstrated that exposure to ambient PM in juvenile mice enhanced adult asthma development, as shown by increased Th2 responses, which might be associated with the persistent effects resulting from the oxidative stress and decreased gene expression of DNMTs induced by PM exposure. The observed differences between the effects of three size-fractionated particulates were attributed to particle sizes and chemical constituents, including heavy metals and also PAHs, since the amounts of PAH associated with more severe toxicity were enriched equivalently in the F1 and F2 fractions. Relative to the often mentioned PM2.5, PM with an aerodynamic diameter smaller than 0.95 μm had a more aggravating effect on asthma development.

Restoration of the type I IFN-IL-1 balance through targeted blockade of PTGER4 inhibits autoimmunity in NOD mice.

Type I IFN (IFN-I) dysregulation contributes to type 1 diabetes (T1D) development, and although increased IFN-I signals are pathogenic at the initiation of autoimmune diabetes, IFN-I dysregulation at later pathogenic stages more relevant for therapeutic intervention is not well understood. We discovered that 5 key antigen-presenting cell subsets from adult prediabetic NOD mice have reduced responsiveness to IFN-I that is dominated by a decrease in the tonic-sensitive subset of IFN-I response genes. Blockade of IFNAR1 in prediabetic NOD mice accelerated diabetes and increased Th1 responses. Therefore, IFN-I responses shift from pathogenic to protective as autoimmunity progresses, consistent with chronic IFN-I exposure. In contrast, IL-1-associated inflammatory pathways were elevated in prediabetic mice. These changes correlated with human T1D onset-associated gene expression. Prostaglandin E2 (PGE2) and prostaglandin receptor 4 (PTGER4), a receptor for PGE2 that mediates both inflammatory and regulatory eicosanoid signaling, were higher in NOD mice and drive innate immune dysregulation. Treating prediabetic NOD mice with a PTGER4 antagonist restored IFNAR signaling, decreased IL-1 signaling, and decreased infiltration of leukocytes into the islets. Therefore, innate cytokine alterations contribute to both T1D-associated inflammation and autoimmune pathogenesis. Modulating innate immune balance via signals such as PTGER4 may contribute to treatments for autoimmunity.

Increased BATF expression is associated with the severity of liver damage in patients with chronic hepatitis B.

T helper (Th) 17 cells have a critical role in the pathogenesis of chronic hepatitis B virus (HBV) infection, and basic leucine zipper transcription factor, ATF-like (BATF) is a newly identified transcriptional factor regulating the differentiation of Th17 cells. However, its precise role in patients with chronic hepatitis B remains unclear. Sixty chronic hepatitis B (CHB) patients, twenty-two acute-on-chronic hepatitis B liver failure (ACHBLF) patients and seventeen healthy controls were included in our study. Both peripheral and intrahepatic expressions of BATF were analyzed by flow cytometry, quantitative real-time polymerase chain reaction and immunohistochemical staining. Peripheral BATF mRNA and protein expression levels were higher in CHB patients than those in healthy controls. Particularly in ACHBLF patients, the BATF mRNA and protein levels were further increased over those in CHB patients. Intrahepatic BATF-positive infiltrating cells were enriched in portal area of CHB patients, and more positive cells were found in patients with higher inflammation grade. Peripheral BATF expression was positively correlated with serum parameters of liver injury and plasma HBV DNA load. Furthermore, a positive correlation was found between the frequency of BATF-positive CD3+ T cells and the increased Th17 response in chronic HBV-infected patients. BATF over-expression might augment Th17 cell response and relate to the disease progression of CHB.

Pir-B inhibits the DC function and disturbs the Th17/Treg balance in lung cancer murine model.

Paired immunoglobulin-like receptor B (Pir-B) was an inhibitory receptor expressed on the surfaces of dendritic cells (DCs). Pir-B inhibit T helper (Th) 1 response and induce Th2 cell differentiation, leading to the imbalance of Th1/Th2 cells. However, the role and potential mechanism of Pir-B on the balance of Th17/regulatory T cells (Tregs) is still largely unknown in lung cancer murine model. In the present study, the DC function and Th17/Treg balance were destroyed during the progression of lung cancer and this was accompanied by an increased expression of Pir-B. After transfection with Pir-B siRNA or administration of IL-6 in vitro, the decreased response of Th17 cells were restored, whereas the augmented differentiation of Tregs was diminished. Further, the transfer of Pir-B silenced DCs or the injection of IL-6 in vivo increased Th17 response and decreased Treg differentiation. Our study has demonstrated that Pir-B inhibits the DC function and disturbs the Th17/Treg balance via IL-6 pathway during the progression of lung cancer, contributing to inhibited antitumor immunity.