Oclacitinib, a Janus Kinase Inhibitor, Reduces the Frequency of IL-4- and IL-10-, but Not IFN-γ-, Producing Murine CD4+ and CD8+ T Cells and Counteracts the Induction of Type 1 Regulatory T Cells

The purpose of the present study was to broaden the knowledge and understanding of the effects of oclacitinib (OCL), a Janus kinase inhibitor, on T cells in the context of both the immune mechanisms underlying anti-inflammatory and anti-allergic properties of the drug and its safety. The results indicate that beneficial effects of OCL in the treatment of skin allergic diseases may be partially mediated by the inhibition of IL-4 production in CD4⁺ and CD8⁺ T cells. To a certain extent, the antiproliferative effect of OCL on CD8⁺ T cells may also contribute to its therapeutic effect. The study found that OCL does not affect the proliferation of CD4⁺ T cells or the number of IFN-γ- and IL-17-producing CD4⁺ and CD8⁺ T cells. Moreover, OCL was found to counteract the induction of type 1 regulatory T (Tr1) cells and to act as a strong inhibitor of IL-10 production in both CD4⁺ and CD8⁺ T cells. Thus, these results indicate that beneficial effects of OCL in the treatment of skin allergic diseases are not mediated through: (a) the abolishment of IFN-γ and IL-17-production in CD4⁺ and CD8⁺ T cells; (b) generation of Tr1 cells; (c) inhibition of CD4⁺ T cell proliferation; (d) induction of IL-10 production in CD4⁺ T cells. The results of this study strongly suggest that, with respect to the evaluated parameters, OCL exerts a suppressive effect on Th2- but not Th1-mediated immunity.

Potent Neutralizing Antibodies Elicited by RBD-Fc-Based COVID-19 Vaccine Candidate Adjuvanted by the Th2-Skewing iNKT Cell Agonist

The development of a safe and effective COVID-19 vaccine is of paramount importance to terminate the current pandemic. An adjuvant is crucial for improving the efficacy of the subunit COVID19 vaccine. α-Galactosylceramide (αGC) is a classical iNKT cell agonist which causes the rapid production of Th1- and Th2-associated cytokines; we, therefore, expect that the Th1- or Th2-skewing analogues of αGC can better enhance the immunogenicity of the receptor-binding domain in the spike protein of SARS-CoV-2 fused with the Fc region of human IgG (RBD-Fc). Herein, we developed a universal synthetic route to the Th1-biasing (α-C-GC) and Th2-biasing (OCH and C20:2) analogues. Immunization of mice demonstrated that αGC-adjuvanted RBD-Fc elicited a more potent humoral response than that observed with Alum and enabled the sparing of antigens. Remarkably, at a low dose of the RBD-Fc protein (2 μg), the Th2-biasing agonist C20:2 induced a significantly higher titer of the neutralizing antibody than that of Alum.

Follicular T Helper and Breg Cell Balance in Severe Allergic Asthma Before and After Omalizumab Therapy

Background

Severe allergic asthma (SAA) is based on type 2 (T2-high) immune responses to allergens promoting type 2 T helper (Th2) cell cytokine responses and production of IgE antibodies. Omalizumab was the first biological drug licensed for clinical use in the management of IgE-mediated SAA. Despite emerging evidence supporting the prominent role of follicular T cells (Tfh), Breg and Treg subsets, in the development and progression of SAA, no data are available on the impact of omalizumab therapy.

Methods

Ten SAA patients monitored at the Respiratory Diseases Unit of Siena University Hospital and ten healthy sex- and age-matched controls were enrolled in the study. Clinical and functional parameters were collected at baseline (T0) and after 6 months of therapy (T6). Cellular population analysis was determined through multicolour flow cytometry.

Results

SAA patients showed higher percentages of Th17.1, Tfh and Tfh2 while CD24^hiCD27^hi Breg cell, Treg and Tfr percentages were significantly lower than in controls. Higher percentages of Tfh2 in patients with nasal polyps than in those without and in controls were observed. At T6, significant decreases in Tfh and Tfh2 compared with T0 were observed. A slightly significant increase in Teffs was reported at T6 compared to T0. ΔIgE levels in serum were correlated with ΔCD19⁺CD24⁺CD27⁺ Breg cell percentages (r = − 0.86, p = 0.0022).

Conclusions

Our data explored the changes in Tfh cells, Tregs and Bregs in severe asthma. The restoration of immunological imbalance in SAA patients after omalizumab is certainly intriguing and represents a glimpse into the comprehension of immunological effects of treatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40291-021-00545-3.

Overexpression of helper T cell type 2-related molecules in the skin of patients with eosinophilic dermatosis of hematologic malignancy

BACKGROUND

Eosinophilic dermatosis of hematologic malignancy (EDHM) is a rare dermatosis associated with blood tumors.

OBJECTIVE

To characterize the expression of T-cell and B-cell markers and pruritogenic mediators in EDHM skin.

METHODS

Immunohistochemical and immunofluorescence analysis were performed in 12 skin samples of EDHM, 11 samples of bullous pemphigoid (BP), and 5 samples from healthy controls (HC). Serum levels of interleukin (IL) 4 were analyzed in 11 patients with EDHM, 11 BP patients, and 5 HC by enzyme-linked immunosorbent assay.

RESULTS

T-cell markers, including clusters of differentiation (CD) 3, CD4, CD8, and CD5 were significantly overexpressed in EDHM and BP skin compared to HC. A predominance of CD4⁺ over CD8⁺ cells and GATA3⁺ (helper T cell type 2 [Th2] marker) over T-bet⁺ (Th1 marker) cells were observed. FOXP3 expression was increased but the FOXP3/CD4 ratio was low. B-cell markers were under-represented, without significant differences between the 3 groups. IL-4 and IL-31 were significantly overexpressed in EDHM and BP compared to HC and colocalized with the Th2-associated marker GATA3. Eotaxin-1 was significantly overexpressed in EDHM compared to BP and HC. IL-4 serum concentration was significantly increased in EDHM and BP compared to HC.

LIMITATIONS

Small sample size; retrospective design.

CONCLUSIONS

Targeting Th2-related molecules, in particular IL-4, holds promise for EDHM management.

Vitamin D3-elicited CD14+ human skin dendritic cells promote thymic stromal lymphopoietin-independent type 2 T-helper responses

BACKGROUND

Immune modulation by vitamin D3 through dendritic cells (DCs) remains controversial. Human DCs exposed in vitro counteract type-1 T-helper (Th1) differentiation and induce regulatory T cells. However, cutaneous application on mice promotes Th2-driven inflammation resembling atopic dermatitis and relying on thymic stromal lymphopoietin (TSLP) from keratinocytes and T-cell orientation by TSLP-stimulated skin DCs. We studied the effects of vitamin D3 in human skin, focusing on TSLP production and the role of skin DCs in T-cell differentiation.

METHODS

Human healthy skin explants were exposed in vitro to vitamin D3 analogs. Migrating DCs were analyzed and TSLP quantified in the supernatant. Allogeneic naïve CD4+ T cells were cocultured with DCs to assess their proliferation and cytokine production.

RESULTS

Vitamin D3 induced skin DCs to differentiate Th2 cells producing IL-4 and IL-13. Vitamin D3 triggered TSLP release in ~30% of skin explants, correlating with IL-13 detection in Th2 cells. In these donors, blocking TSLP receptor during skin explant cultures abrogated IL-13 production, yet IL-4+ Th2 cells were unaffected. Among skin DCs emerged CD14+ cells that had responded directly to vitamin D3 and differed from classical CD14+ dermal emigrants. Vitamin D3-elicited CD14+ DCs sufficed to promote IL-4+ Th2 cells in a TSLP-independent manner.

CONCLUSION

Vitamin D3, despite inducing TSLP in some donors, had a direct influence on skin DCs, affecting their phenotype and ability to drive Th2 responses independently of TSLP. Our findings pave the way toward in vitro systems that accurately model human cutaneous Th2 responses, notably involved in atopic dermatitis.

The immunogenic reaction and bone defect repair function of ε-poly-L-lysine (EPL)-coated nanoscale PCL/HA scaffold in rabbit calvarial bone defect

Tissue engineering is a promising strategy for bone tissue defect reconstruction. Immunogenic reaction, which was induced by scaffolds degradation or contaminating microorganism, influence cellular activity, compromise the efficiency of tissue engineering, or eventually lead to the failure of regeneration. Inhibiting excessive immune response through modulating scaffold is critical important to promote tissue regeneration. Our previous study showed that ε-poly-L-lysine (EPL)-coated nanoscale polycaprolactone/hydroxyapatite (EPL/PCL/HA) composite scaffold has enhanced antibacterial and osteogenic properties in vitro. However, the bone defect repair function and immunogenic reaction of EPL/PCL/HA scaffolds in vivo remains unclear. In the present study, three nanoscale scaffolds (EPL/PCL/HA, PCL and PCL/HA) were transplanted into rabbit paraspinal muscle pouches, and T helper type 1 (Th1), T helper type 2 (Th2), T helper type 17 (Th17), and macrophage infiltration were analyzed after 1 week and 2 weeks to detect their immunogenic reaction. Then, the different scaffolds were transplanted into rabbit calvarial bone defect to compare the bone defect repair capacities. The results showed that EPL/PCL/HA composite scaffolds decreased pro-inflammatory Th1, Th17, and type I macrophage infiltration from 1 to 2 weeks, and increased anti-inflammatory Th2 infiltration into the regenerated area at 2 weeks in vivo, when compared to PCL and PCL/HA. In addition, EPL/PCL/HA showed an enhanced bone repair capacity compared to PCL and PCL/HA when transplanted into rabbit calvarial bone defects at both 4 and 8 weeks. Hence, our results suggest that EPL could regulate the immunogenic reaction and promote bone defect repair function of PCL/HA, which is a promising agent for tissue engineering scaffold modulation.

Derangement of cell cycle markers in peripheral blood mononuclear cells of asthmatic patients as a reliable biomarker for asthma control

In asthma, most of the identified biomarkers pertain to the Th2 phenotype and no known biomarkers have been verified for severe asthmatics. Therefore, identifying biomarkers using the integrative phenotype-genotype approach in severe asthma is needed. The study aims to identify novel biomarkers as genes or pathways representing the core drivers in asthma development, progression to the severe form, resistance to therapy, and tissue remodeling regardless of the sample cells or tissues examined. Comprehensive reanalysis of publicly available transcriptomic data that later was validated in vitro, and locally recruited patients were used to decipher the molecular basis of asthma. Our in-silicoanalysis revealed a total of 10 genes (GPRC5A, SFN, ABCA1, KRT8, TOP2A, SERPINE1, ANLN, MKI67, NEK2, and RRM2) related to cell cycle and proliferation to be deranged in the severe asthmatic bronchial epithelium and fibroblasts compared to their healthy counterparts. In vitro, RT qPCR results showed that (SERPINE1 and RRM2) were upregulated in severe asthmatic bronchial epithelium and fibroblasts, (SFN, ABCA1, TOP2A, SERPINE1, MKI67, and NEK2) were upregulated in asthmatic bronchial epithelium while (GPRC5A and KRT8) were upregulated only in asthmatic bronchial fibroblasts. Furthermore, MKI76, RRM2, and TOP2A were upregulated in Th2 high epithelium while GPRC5A, SFN, ABCA1 were upregulated in the blood of asthmatic patients. SFN, ABCA1 were higher, while MKI67 was lower in severe asthmatic with wheeze compared to nonasthmatics with wheezes. SERPINE1 and GPRC5A were downregulated in the blood of eosinophilic asthmatics, while RRM2 was upregulated in an acute attack of asthma. Validation of the gene expression in PBMC of locally recruited asthma patients showed that SERPINE1, GPRC5A, SFN, ABCA1, MKI67, and RRM2 were downregulated in severe uncontrolled asthma. We have identified a set of biologically crucial genes to the homeostasis of the lung and in asthma development and progression. This study can help us further understand the complex interplay between the transcriptomic data and the external factors which may deviate our understanding of asthma heterogeneity.

The human immune response to saliva of Phlebotomus alexandri, the vector of visceral leishmaniasis in Iraq, and its relationship to sand fly exposure and infection

Background

Sand fly saliva exposure plays an important role in immunity against leishmaniasis where it has mostly been associated with protection. Phlebotomus (Ph.) alexandri transmits Leishmania (L.) infantum, the causative agent of visceral leishmaniasis (VL), in Iraq. Our group recently demonstrated that 20% of Operation Iraqi Freedom (OIF) deployers had asymptomatic VL (AVL) indicative of prior infection by the parasite L. infantum. Little is known about Ph. alexandri saliva, and the human immune response to it has never been investigated. Here, we characterize the humoral and cellular immune response to vector saliva in OIF deployers naturally exposed to bites of Ph. alexandri and characterize their immunological profiles in association to AVL.

Methodology/Principal findings

The humoral response to Ph. alexandri salivary gland homogenate (SGH) showed that 64% of 200 OIF deployers developed an antibody response. To assess the cellular immune response to saliva, we selected a subcohort of subjects based on their post-travel (median 4 months; range 1–22 months) antibody response (SGH Antibody [Ab] positive or negative) as well as their AVL status; ten never-traveled controls were also included. Banked peripheral blood mononuclear cells (PBMC), collected ~10 years after end of deployment, were stimulated with SGH for 96 hours. The levels of IFN- γ, IL-6, IL-10, IL-13 and IL-17 were determined by ELISA. Our findings indicate that OIF deployers mounted a cellular response to SGH where the anti-SGH+ asymptomatic subjects developed the highest cytokine levels. Further, stimulation with SGH produced a mixture of pro-inflammatory and anti-inflammatory cytokines. Contrary to our hypothesis, we observed no correlation between the cellular immune response to Ph. alexandri SGH and prevention from asymptomatic infection with L. infantum.

Conclusions/Significance

As we found, although all infected deployers demonstrated persistent disease control years after deployment, this did not correlate with anti-saliva systemic cellular response. More exposure to this vector may facilitate transmission of the L. infantum parasite. Since exposure to saliva of Ph. alexandri may alter the human immune response to bites of this vector, this parameter should be taken into consideration when considering the VL risk.

This is the first report of human immune responses to Phlebotomus alexandri. Phlebotomus alexandri is a sand fly found in Southwest Asia and is the vector for transmission of the parasite Leishmania infantum, agent of visceral leishmaniasis. During the bite of this sand fly, a small amount of saliva is injected into the skin. In this study, we report the human immune response to Phlebotomus alexandri saliva. We found that 64% of people who traveled to endemic Iraq developed antibodies directed toward this sand fly’s saliva. This suggests that saliva is very immunogenic and that anti-saliva immune responses could be a good indicator of vector exposure. Additionally, we studied the cellular immune responses in saliva-stimulated white blood cells and found a Th2 biased cytokine profile.

Characterization of systemic allergenicity of tropomyosin from shrimp (Macrobrachium nipponense) and anaphylactic reactions in digestive tract

BACKGROUND

Tropomyosin (TM) is the major allergen of crustaceans. The allergenicity of TM from Macrobrachium nipponense (MnTM) and the anaphylactic reaction in the digestive tract are still unclear. The aim of this study was to evaluate the allergenicity of MnTM and the anaphylactic reaction in the digestive tract.

RESULTS

Serum IgE and IgG1 binding ability in the TM group were significantly higher than those in the PBS and CT groups (P < 0.01) and CP group (P < 0.05), while serum IgG and IgG2a binding ability showed no obvious difference between the four groups (P > 0.05). The levels of cytokines IL-4, IL-5 and IL-13 in TM and CP groups were significantly higher than those in PBS and CT groups. Histamine and β-hexosaminidase in the TM and CP groups from basophil cell models were significantly higher than those in the PBS group. The highest mRNA expression of IL-4 and IL-13 was in the jejunum from TM-sensitized mice. Histopathological analysis showed that more immune cells infiltrated into the jejunum than the duodenum and ileum from the TM-sensitized mice.

CONCLUSIONS

MnTM could promote an allergic response in mice and lead to degranulation in basophil cells. The jejunum was more easily affected by MnTM than duodenum and ileum, and the jejunum may be the major site of allergic response in the digestive tract. © 2020 Society of Chemical Industry.

Asthma in the Precision Medicine Era: Biologics and Probiotics

Asthma is a major global health issue. Over 300 million people worldwide suffer from this chronic inflammatory airway disease. Typical clinical symptoms of asthma are characterized by a recurrent wheezy cough, chest tightness, and shortness of breath. The main goals of asthma management are to alleviate asthma symptoms, reduce the risk of asthma exacerbations, and minimize long-term medicinal adverse effects. However, currently available type 2 T helper cells (Th2)-directed treatments are often ineffective due to the heterogeneity of the asthma subgroups, which manifests clinically with variable and poor treatment responses. Personalized precision therapy of asthma according to individualized clinical characteristics (phenotype) and laboratory biomarkers (endotype) is the future prospect. This mini review discusses the molecular mechanisms underlying asthma pathogenesis, including the hot sought-after topic of microbiota, add-on therapies and the potential application of probiotics in the management of asthma.

Fluoride Can Damage the Spleen of Mice by Perturbing Th1/Th2 Cell Balance

To investigate the mechanism of fluoride-induced splenic toxicity, 0, 25, 50, and 100 mg/L sodium fluoride (NaF) were administered in male mice via drinking water for 90 days. After NaF treatment, the histological structure of the spleen, the proportion of helper T 1 cell (Th1) and helper T 2 cell (Th2), and the relative expression levels of cytokines and T-bet and GATA3 were analyzed. The results showed that 50 and 100 mg/L NaF consumption can change the normal structure of mouse spleen and the proportion of Th1/Th2 cells. It also decreased the mRNA expression levels of IL-2, INF-γ, and TGF-β, but increased the levels of IL-4, IL-6, and IL-10. Importantly, fluoride increased the protein expression of GATA3 but decreased the expression of T-bet. Our findings indicate that superfluous fluoride intake damages the balance of Th1/Th2 cells by changing the levels of T-bet and GATA3 in the spleen, and further changes the expression of Th1/Th2 cell-related cytokines in the spleen microenvironment, eventually leading to spleen injury.

l-Arabinose Attenuates Gliadin-Induced Food Allergy via Regulation of Th1/Th2 Balance and Upregulation of Regulatory T Cells in Mice

Gliadins are the main cause of wheat allergies, and the prevalence of gliadin allergy has increased in many countries. l-Arabinose, a kind of plant-specific five-carbon aldose, possesses beneficial effects on food allergy to gliadins. This study investigated the antiallergic activities and underlying mechanisms of l-arabinose in a wheat gliadin-sensitized mouse model. BALB/c mice were sensitized to gliadin by intraperitoneal injections with gliadin followed by being given a gliadin challenge. l-arabinose-treated mice exhibited a marked reduction in the productions of total immunoglobulin E (IgE), gliadin-specific IgE, gliadin-specific IgG1, and histamine, with an increase in IgG2a level as compared with gliadin-sensitized mice. Beside that, a significant decrease in Th2-related cytokine level, IL-4, and an increase in Th1-related cytokine level, IFN-γ, in the serum and splenocytes were observed after treatment with l-arabinose. l-Arabinose treatment also improved the imbalance of Th1/Th2 immune response on the basis of the expression levels of related cytokines and key transcription factors in the small intestine and spleen of sensitized mice. In addition, gliadin-induced intestinal barrier impairment was blocked by l-arabinose treatment via regulation of TJ proteins and suppression of p38 MAPK and p65 NF-κB inflammation signaling pathways. Notably, the results confirmed that l-arabinose treatment increased CD4⁺ Foxp3⁺ T cell populations and Treg-related factors associated with increased expression of IL-2 and activation of STAT5 in gliadin-sensitized mice. In conclusion, l-arabinose attenuated the gliadin-induced allergic symptoms via maintenance of Th1/Th2 immune balance and regulation of Treg cells in a gliadin-induced mouse model, suggesting l-arabinose could be used as a promising agent to alleviate gliadin allergy.

Innate and Adaptive Immunity: ILC2 and Th2 Cells in Upper and Lower Airway Allergic Diseases

Advances in our understanding of the immune system, with the recent discovery of a parallel set of innate T lymphocytes, the innate lymphocytes (ILCs), have led to a reassessment of the pathogenesis of allergic and eosinophilic airway disorders, including allergic rhinitis (AR), asthma, and chronic rhinosinusitis with nasal polyps. We review current understanding of both elements of type-2 inflammatory responses and their relative influence in these common conditions and consider possible impacts of this on treatment selection.

Infiltrated regulatory T cells and Th2 cells in the brain contribute to attenuation of sepsis-associated encephalopathy and alleviation of mental impairments in mice with polymicrobial sepsis

Sepsis-associated encephalopathy (SAE) increases not only morbidity and mortality but has been associated with long-lasting mental impairment after hospital discharge in septic patients. Recently, studies have shown that these mental impairments are caused by infection-induced neuroinflammation. However, the role of T cells in the pathogenesis of SAE and mental impairments remains unclear. Thus, in this study, we aimed to clarify how immune cells, especially T cells, influence the development and recovery of these disorders. In the cecal slurry (CS)-induced septic mouse model, we performed three different kinds of behavioral tests, open-field test, marble burying test, and forced swimming test, and observed anxiety-like behavior in septic mice. Additionally, increased interleukin (IL)-1β and IL-6 expression levels, and infiltration of neutrophils and T cells were examined in the brain of septic mice, 10 days after sepsis onset. Twenty days after sepsis onset, the septic mice could recover the number of astrocytes. At day 30, expression levels of IL-1β and tumor necrosis factor (TNF)-α returned to normal levels in the cerebral cortex of septic mice. Interestingly, resolution of neuroinflammation and alleviation of depression were delayed in septic mice treated with FTY720, which inhibits sphingosine-1-phosphate (S1P)-dependent lymphocyte egress from lymph nodes. On analyzing the brain T cells with or without FTY720 in septic mice, the FTY720 untreated mice presented increased regulatory T cells (Treg) and Th2 cells in the brain, whereas the FTY720 treated mice demonstrated increased Th17 in the brain at day 30. Furthermore, in FTY720 treated septic mice, the number of astrocytes in the cerebral cortex remained reduced at day 30. These results suggest that infiltrated Treg and Th2 cells contribute to the attenuation SAE and alleviate SAE-induce mental disorder by resolving neuroinflammation in the chronic phase of sepsis.

[miR-139 promotes homing of bone marrow mesenchymal stem cells (BMSCs) to lung tissues of asthmatic rats to inhibit inflammatory response of Th2 cells by down-regulating Notch1/Hes1 pathway]

Objective To study the effects of microRNA-139 (miR-139) regulating Notch signaling pathway on bone mesenchymal stem cells (BMSCs) homing and asthma airway inflammation. Methods Twenty-four SD rats were randomly divided into normal control group, model control group and BMSCs group. The rats were challenged with ovalbumin and then BMSCs were transplanted into the rats. Pathological changes in lung tissues were observed by HE staining. The expression of BMSCs marker C-X-C motif chemokine receptor 4 (CXCR4) in the lung tissues was examined by flow cytometry, and the expression of CXCR4 in bronchial epithelial cells was observed by immunofluorescence staining. The expression of interferon-γ (IFN-γ) and interleukins-4 (IL-4) were detected by ELISA, and the expression of Notch1, Jagged1 and Hes1 in the lung tissues were tested by Western blot analysis. Results Compared with the normal control group, the expression of CXCR4, IL-4, Notch1 and Hes1 in the lung tissues of the model control group increased significantly, and the ratio of Th1/Th2 cells and the level of miR-139 mRNA decreased. Compared with the model control group, the expression of CXCR4 in the lung tissues and bronchial epithelial cells increased, so were the ratio of Th1/Th2 cells and the level of miR-139 mRNA, while the expression of Notch1 and Hes1 decreased. Correlation analysis showed that the expression of CXCR4 in the lung tissues was positively correlated with the expression of CXCR4 in bronchial epithelial cells, the ratio of Th1/Th2 cells, and miR-139. The expression of CXCR4 in bronchial epithelial cells was positively correlated with the ratio of Th1/Th2 cells, the expression of miR-139, and negatively correlated with the expression of Notch1. The ratio of Th1/Th2 cells was positively correlated with the expression of miR-139. Conclusion miR-139 can down-regulate the Notch pathway and promote BMSCs homing in asthmatic lung tissues, thus suppressing the inflammatory response of Th2 cells through immune regulation.

Ex Vivo Expansion of Th2-Polarizing Immunotherapeutic iNKT Cells from Human Peripheral Blood

iNKT cells, classified as innate lymphocytes with invariant TCRs, have been highlighted as a putative, "off-the-shelf" cellular immunotherapeutic strategy for the treatment of malignant and nonmalignant diseases. However, their paucity in human blood limits their immunotherapeutic applications. Herein we describe a rigorously optimized 21-day ex vivo expansion method to achieve log-fold increases in immunotherapeutic human iNKT cells.

Total Phenolic Fraction (TPF) from Extra Virgin Olive Oil: Induction of apoptotic-like cell death in Leishmania spp. promastigotes and in vivo potential of therapeutic immunomodulation

BACKGROUND

Leishmaniasis is a serious multifactorial parasitic disease with limited treatment options. Current chemotherapy is mainly consisted of drugs with serious drawbacks such as toxicity, variable efficacy and resistance. Alternative bioactive phytocompounds may provide a promising source for discovering new anti-leishmanial drugs. Extra Virgin Olive Oil (EVOO), a key-product in the Mediterranean diet, is rich in phenols which are associated with anti-inflammatory, anti-cancer and anti-microbial effects. In this study, we investigate the anti-leishmanial effect of Total Phenolic Fraction (TPF) derived from EVOO in both in vitro and in vivo systems by investigating the contributing mechanism of action.

METHODOLOGY/PRINCIPAL FINDINGS

We tested the ability of TPF to cause apoptotic-like programmed cell death in L. infantum and L. major exponential-phase promastigotes by evaluating several apoptotic indices, such as reduction of proliferation rate, sub-G0/G1 phase cell cycle arrest, phosphatidylserine externalization, mitochondrial transmembrane potential disruption and increased ROS production, by using flow cytometry and microscopy techniques. Moreover, we assessed the therapeutic effect of TPF in L. major-infected BALB/c mice by determining skin lesions, parasite burden in popliteal lymph nodes, Leishmania-specific antibodies and biomarkers of tissue site cellular immune response, five weeks post-treatment termination. Our results show that TPF triggers cell-cycle arrest and apoptotic-like changes in Leishmania spp. promastigotes. Moreover, TPF treatment induces significant reduction of parasite burden in draining lymph nodes together with an antibody profile indicative of the polarization of Th1/Th2 immune balance towards the protective Th1-type response, characterized by the presence of IFN-γ-producing CD4+ T-cells and increased Tbx21/GATA-3 gene expression ratio in splenocytes.

CONCLUSIONS/SIGNIFICANCE

TPF exhibits chemotherapeutic anti-leishmanial activity by inducing programmed cell death on cell-free promastigotes and immunomodulatory properties that induce in vivo T cell-mediated responses towards the protective Th1 response in experimental cutaneous leishmaniasis. These findings enable deeper understanding of TPF's dual mode of action that encourages further studies.

Peripheral Blood Immune Profiling of Convalescent Plasma Donors Reveals Alterations in Specific Immune Subpopulations Even at 2 Months Post SARS-CoV-2 Infection

Immune profiling of patients with COVID-19 has shown that SARS-CoV-2 causes severe lymphocyte deficiencies (e.g., lymphopenia, decreased numbers, and exhaustion of T cells) and increased levels of pro-inflammatory monocytes. Peripheral blood (PB) samples from convalescent plasma (CP) donors, COVID-19 patients, and control subjects were analyzed by multiparametric flow cytometry, allowing the identification of a wide panel of immune cells, comprising lymphocytes (T, B, natural killer (NK) and NKT cells), monocytes, granulocytes, and their subsets. Compared to active COVID-19 patients, our results revealed that the immune profile of recovered donors was restored for most subpopulations. Nevertheless, even 2 months after recovery, CP donors still had reduced levels of CD4+ T and B cells, as well as granulocytes. CP donors with non-detectable levels of anti-SARS-CoV-2-specific antibodies in their serum were characterized by higher Th9 and Th17 cells, which were possibly expanded at the expense of Th2 humoral immunity. The most noticeable alterations were identified in previously hospitalized CP donors, who presented the lowest levels of CD8+ regulatory T cells, the highest levels of CD56+CD16- NKT cells, and a promotion of a Th17-type phenotype, which might be associated with a prolonged pro-inflammatory response. A longer follow-up of CP donors will eventually reveal the time needed for full recovery of their immune system competence.

A Potential Role for IL-4 and IL-13 in an Alopecia Areata-Like Phenotype: A Clinical Perspective

Although alopecia areata (AA) has been traditionally classified as a strictly T helper type 1-mediated process, the T helper type 2 (Th2) pathway may contribute to an AA-like phenotype in some individuals. Herein, we describe three clinical cases that support the potential role of Th2 activity through the upregulation of IL-4 and IL-13 in an AA-like phenotype.

Sargassum horneri extract containing mojabanchromanol attenuates the particulate matter exacerbated allergic asthma through reduction of Th2 and Th17 response in mice

Airborne particulate matter (PM) has become a serious health issue causing pulmonary diseases such as asthma. Due to the side effects and non-specificity of conventional drugs, there is a need to develop natural-product-based alternative treatments. Sargassum horneri is a brown alga shown to have anti-oxidant, anti-inflammatory, and anti-allergic effects. Thus, we sought to determine whether ethanol extract of Sargassum horneri (SHE) mitigates the effect of PM exposure on asthma development. To establish a mouse model of asthma, BALB/c mice were sensitized with ovalbumin (OVA, 10 μg) and challenged with PM (5 mg/m3) for 7 days consecutively. SHE (200, 400 mg/kg), Prednisone (5 mg/kg), or PBS was daily administrated orally before PM exposure. SHE mitigated PM exacerbated dendritic cell activation. More importantly, SHE restrained Th2 polarization by attenuating transcription factors GATA3 and STAT5, which further mitigated the expression of Th2 cytokines interleukin (IL)-4, IL-5, and IL-13 in the lung homogenates of PM-exacerbated asthmatic mice. SHE further attenuated PM-exacerbated eosinophil infiltration in the lung, trachea, and BALF. In addition, SHE markedly mitigated the activation of mast cells and the IgE level in serum. Concomitantly, SHE further restrained the Th17 cell response in PM-exposed allergic mice through attenuating expression of transcription factors RORγT, STAT3 and expression of relevant effector cytokines IL-17a. This resulted in mitigated neutrophil infiltration in the lung. Taken together, SHE significantly suppressed PM-exacerbated hypersecretion of mucus in asthmatic mice. These results suggest that SHE has therapeutic potential for treating PM-exacerbated allergic asthma through concomitantly inhibiting Th2/Th17 responses.

Effects of Ursolic Acid on the Expression of Th1-Th2-related Cytokines in a Rat Model of Allergic Rhinitis After PM2.5 Exposure

BACKGROUND

Allergic rhinitis (AR) is a global health problem and closely related to environmental factors. Ursolic acid (UA) has potential in the treatment of allergic inflammation. The effects of UA intervention on PM2.5-induced AR remain uncertain.

OBJECTIVE

To assess the effects of UA on nasal symptoms and the expression of T-helper (Th)1-Th2-related cytokines in a rat model of AR after fine particulate matter (particulate matter ≤ 2.5 µm [PM2.5]) exposure.

METHODS

A total of 40 healthy female Sprague-Dawley rats were randomly divided into 4 groups: normal control group (NC group), ovalbumin (OVA)- induced AR model (AR group), PM2.5-exposed AR group exposed to 200 g/m3 PM2.5 for 30 days via inhalation (ARE group), and a group with UA intervention to the AR model after PM2.5 exposure (UA group). UA intervention was adopted after PM2.5 exposure in the UA group. Nasal symptoms and levels of Th1-Th2 cytokines in the serum were detected in each individual rat. The pathological changes and expression of Eotaxin in the nasal mucosa of each individual rat were examined by histology.

RESULTS

PM2.5 significantly increased the number of sneezes and nasal rubs in the rats with AR, and UA alleviated these symptoms. UA decreased interleukin (IL)-4, IL-5, IL-13, Eotaxin-1, and OVA Immunoglobulin E (IgE) protein levels. In the AR group, hematoxylin and eosin staining showed disordered arrangement of the nasal mucosa epithelium, cell shedding, eosinophilic infiltration, swelling of the glands, and submucosal vascular congestion. UA group showed reduced eosinophilic infiltration and orderly arrangement of the mucosal epithelium when compared with the ARE group. Immunohistochemical results showed that the expression of Eotaxin in the UA group was lower than that in the ARE group.

CONCLUSION

UA could relieve nasal symptoms caused by PM2.5 exposure, the possible mechanism of which is to inhibit the expression of Th2 cytokines, eosinophilic infiltration, and specific IgE production.

[Expressions of Th1/Th2 cytokines and autoantibodies in the serum of males with idiopathic oligoasthenozoospermia and their significance]

OBJECTIVE

To investigate the expressions of Th1/Th2 cytokines and autoantibodies in the serum of the patients with idiopathic oligoasthenozoospermia (IO) and their significance.

METHODS

From November 2017 to April 2020, we examined the levels of Th1/Th2 cytokines (IL-2, IL-4, IL-10, IL-21, TNF-α, IFN-γ) and the expressions of AhCGAb, AsAb and AcAb in the serum of 48 infertile men with mild or moderate IO, 48 with severe IO and another 72 males with normal semen parameters by ELISA. We compared the results of detection among the three groups and analyzed them with the logistic regression model.

RESULTS

Compared with the normal controls, the patients with mild or moderate IO showed significant increases in the levels of IL-10, IL-21 and IFN-γ and the expressions of AhCGAb, AsAb and AcAb (P < 0.05), and so were those of the severe IO group in the levels of all the six cytokines and the expressions of the three autoantibodies (P < 0.05). The levels of IL-2, IL-4, IL-21 and TNF-α and the expressions of AhCGAb and AsAb were even higher in the patients with severe IO than in those with mild or moderate IO (P < 0.05). Multivariate logistic regression analysis showed that the increased levels of IL-21/IL-10 (OR = 1.694, 95% CI: 0.319－4.035, P < 0.05) and positive expressions of AhCGAb (OR = 4.357, 95% CI: 1.204－9.426, P < 0.05) and AsAb (OR = 2.135, 95% CI: 1.902－5.429, P < 0.05) were the risk factors for IO.

CONCLUSIONS

The levels of the cytokines IL-2, IL-4, IL-10, IL-21, TNF-α and IFN-γ and the expressions of the autoantibodies AhCGAb, AsAb and AoAb are significantly higher in IO patients than in normal healthy males. Quantitative analysis of cytokines and autoantibodies in the serum of IO patients may provide some valuable information for studies of the pathogenesis of male infertility.

STAT2 Limits Host Species Specificity of Human Metapneumovirus

The host tropism of viral infection is determined by a variety of factors, from cell surface receptors to innate immune signaling. Many viruses encode proteins that interfere with host innate immune recognition in order to promote infection. STAT2 is divergent between species and therefore has a role in species restriction of some viruses. To understand the role of STAT2 in human metapneumovirus (HMPV) infection of human and murine tissues, we first infected STAT2-/- mice and found that HMPV could be serially passaged in STAT2-/-, but not WT, mice. We then used in vitro methods to show that HMPV inhibits expression of both STAT1 and STAT2 in human and primate cells, but not in mouse cells. Transfection of the murine form of STAT2 into STAT2-deficient human cells conferred resistance to STAT2 inhibition. Finally, we sought to understand the in vivo role of STAT2 by infecting hSTAT2 knock-in mice with HMPV, and found that mice had increased weight loss, inhibition of type I interferon signaling, and a Th2-polarized cytokine profile compared to WT mice. These results indicate that STAT2 is a target of HMPV in human infection, while the murine version of STAT2 restricts tropism of HMPV for murine cells and tissue.

Effect of deletion of gene cluster involved in synthesis of Enterobacterial common antigen on virulence and immunogenicity of live attenuated Salmonella vaccine when delivering heterologous Streptococcus pneumoniae antigen PspA

BACKGROUND

Enterobacterial common antigen (ECA) is a family-specific surface antigen shared by all members of the Enterobacteriaceae family. Previous studies showed that the loss of ECA results in Salmonella attenuation, indicating its usefulness as a vaccine candidate for Salmonella infection, but no studies have shown whether the mutation resulting from the deletion of the ECA operon in conjunction with other mutations could be used as an antigen vehicle for heterologous protein antigen delivery.

RESULTS

In this study, we introduced a nonpolar, defined ECA operon deletion into wild-type S. Typhimurium χ3761 and an attenuated vaccine strain χ9241, obtaining two isogenic ECA operon mutants, namely, χ12357 and χ12358, respectively. A number of in vitro and in vivo properties of the mutants were analyzed. We found that the loss of ECA did not affect the growth, lipopolysaccharide (LPS) production and motility of S. Typhimurium wild type strain χ3761 and its attenuated vaccine strain χ9241 but significantly affected the virulence when administered orally to BALB/c mice. Furthermore, the effects of the ECA mutation on the immunogenicity of a recombinant S. Typhimurium vaccine strain χ9241 when delivering the pneumococcal antigen PspA were determined. The result showed that the total anti-PspA IgG level of χ12358 (pYA4088) was slightly lower than that of χ9241 (pYA4088), but the protection rate was not compromised.

CONCLUSIONS

ECA affects virulence and benefits the Th2 immunity of Salmonella Typhimurium, therefore, it is feasible to use a reversible ECA mutant mode to design future Salmonella vaccine strains for heterologous protective antigens.

Contribution of Th2-like Treg cells to the pathogenesis of Takayasu's arteritis

OBJECTIVES

Takayasu's arteritis (TAK) involves inflammatory vasculitis of large vessels and mainly affects the aorta and its major branches. Abnormal immunity may play a vital role in TAK pathogenesis. Regulatory T cells (Treg cells) are important for peripheral tolerance, but under certain conditions Treg cells can differentiate into Th-like cells that have lost immune suppressive function and promote the development of autoimmune diseases. The role of Th-like Treg cells in TAK is unclear and this study aims to investigate the function of Th-like Treg cell subsets and associated cytokines in TAK.

METHODS

A total of 51 patients with TAK and 32 healthy controls were enrolled. The percentage of Th1, Th2, Th17, Tregs and Th-like Treg cells in blood samples was analyzed by flow cytometry. Serum cytokine levels were detected using a cytometric bead array for cytokines.

RESULTS

TAK patients had decreased numbers of Th2-like Treg cells in the peripheral blood (p=0.002) relative to healthy controls. The percentage of Treg cells in samples from TAK patients also decreased (p=0.002), but the Th2 cell percentage (p=0.04) increased compared to healthy controls. TAK patients had higher serum levels of IL-4 (p<0.001) and IL-13 (p<0.001) than healthy controls, and levels of both cytokines correlated to IL-6 levels.

CONCLUSIONS

We studied changes in T helper-like Treg cell subsets in TAK for the first time and discovered that the number of Th2-like Treg cells in peripheral blood decreased. Results of this study suggested that Th2-like Treg cells could contribute to TAK pathogenesis.

[Effect of Huai Qi Huang on asthma in rats and the mechanism research]

OBJECTIVE

To study the role and mechanism of action of Huai Qi Huang (HQH) in the rat model of asthma.

METHODS

Forty Sprague-Dawley rats were randomly divided into a control group, an asthma model group, a budesonide group, and an HQH group, with 10 rats in each group. A rat model of asthma was established by ovalbumin sensitization and challenge. The budesonide group was given budesonide aerosol 2 mg before each challenge. The HQH group was given HQH 4 g/kg dissolved in water by gavage before each challenge. Hematoxylin and eosin staining was used to observe the pathological changes of lung tissues. The percentage of eosinophils in bronchoalveolar lavage fluid (BALF) was measured. Enzyme-linked immunosorbent assay was used to determine the levels of interleukin-3 (IL-3), interleukin-4 (IL-4), interleukin-5 (IL-5), interleukin-10 (IL-10), interferon gamma (INF-γ), and immunoglobulin E (IgE) in BALF. Flow cytometry was used to determine T-helper type 1 (Th1)/T-helper type 2 (Th2) ratio in peripheral blood and the spleen. RT-PCR and Western blot were used to measure the mRNA and protein expression of T-bet and GATA-3 in lung tissue.

RESULTS

Compared with the control group, the asthma model group showed significant increases in the degree of airway inflammation, the percentage of eosinophils in BALF, and the levels of IL-3, IL-4, IL-5 and IgE in BALF (P<0.05), however, the asthma model group showed significant reductions in the levels of IL-10 and INF-γ in BALF (P<0.05). The asthma model group had significantly lower percentage of Th1 cells but significantly higher percentage of Th2 cells in peripheral blood and the spleen compared with the control group (P<0.05). The mRNA and protein expression of T-bet in lung tissue was significantly lower, but the mRNA and protein expression of GATA-3 in lung tissue was significantly higher in the asthma group than those in the control group (P<0.05). Both HQH and budesonide significantly improved airway inflammation and the above markers in asthmatic rats (P<0.05), with comparable effects between them. However, there were still significant differences in these indices between the control group and the HQH or budesonide group (P<0.05).

CONCLUSIONS

HQH can reduce the airway inflammation of asthmatic rats and alleviate the symptoms of asthma, possibly by regulating the levels of related cytokines and Th1/Th2 ratio through the T-bet/GATA-3 pathway.

Schistosomal extracellular vesicle-enclosed miRNAs modulate host T helper cell differentiation

During the chronic stage of Schistosoma infection, the female lays fertile eggs, triggering a strong anti-parasitic type 2 helper T-cell (Th2) immune response. It is unclear how this Th2 response gradually declines even though the worms live for years and continue to produce eggs. Here, we show that Schistosoma mansoni downregulates Th2 differentiation in an antigen-presenting cell-independent manner, by modulating the Th2-specific transcriptional program. Adult schistosomes secrete miRNA-harboring extracellular vesicles that are internalized by Th cells in vitro. Schistosomal miRNAs are found also in T helper cells isolated from Peyer's patches and mesenteric lymph nodes of infected mice. In T helper cells, the schistosomal miR-10 targets MAP3K7 and consequently downmodulates NF-κB activity, a critical transcription factor for Th2 differentiation and function. Our results explain, at least partially, how schistosomes tune down the Th2 response, and provide further insight into the reciprocal geographic distribution between high prevalence of parasitic infections and immune disorders such as allergy. Furthermore, this worm-host crosstalk mechanism can be harnessed to develop diagnostic and therapeutic approaches for human schistosomiasis and Th2-associated diseases.

The clinical significance of intrahepatic Th22 cells in liver cirrhosis

BACKGROUND

Th22 cells are a recently identified CD4+ T helper subset and have been implicated in the pathogenesis of certain diseases in humans, but the role of Th22 cells in liver cirrhosis (LC) remains unclear.

OBJECTIVES

The aim of the study was to investigate the expression and clinical significance of intrahepatic Th22 cells in LC tissues.

MATERIAL AND METHODS

Samples of liver tissue of 20 LC patients and 12 normal controls (NC) were collected. Interleukin 22 (IL-22), IL-22R1 mRNA and aryl hydrocarbon receptor (AHR) expression were examined using quantitative reverse transcription polymerase chain reaction (RT-PCR). The protein expression of Th22 and CD4+ cells in liver tissue was measured with immunohistochemistry.

RESULTS

The number of intrahepatic Th22 and CD4+ cells increased markedly in LC patients and the number of Th22 cells positively correlated with the number of CD4+ cells (p < 0.05). Moreover, the number of Th22 cells positively correlated with the serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), as well as the Child-Pugh score in LC patients (p < 0.05). The expression of IL-22, IL-22R1 and AHR in LC patients was significantly increased compared with the NC group (p < 0.05).

CONCLUSIONS

Our findings suggest that the expression of intrahepatic Th22 cells increased in LC patients and was associated with the progression of LC.

Coincident airway exposure to low-potency allergen and cytomegalovirus sensitizes for allergic airway disease by viral activation of migratory dendritic cells

Despite a broad cell-type tropism, cytomegalovirus (CMV) is an evidentially pulmonary pathogen. Predilection for the lungs is of medical relevance in immunocompromised recipients of hematopoietic cell transplantation, in whom interstitial CMV pneumonia is a frequent and, if left untreated, fatal clinical manifestation of human CMV infection. A conceivable contribution of CMV to airway diseases of other etiology is an issue that so far attracted little medical attention. As the route of primary CMV infection upon host-to-host transmission in early childhood involves airway mucosa, coincidence of CMV airway infection and exposure to airborne environmental antigens is almost unavoidable. For investigating possible consequences of such a coincidence, we established a mouse model of airway co-exposure to CMV and ovalbumin (OVA) representing a protein antigen of an inherently low allergenic potential. Accordingly, intratracheal OVA exposure alone failed to sensitize for allergic airway disease (AAD) upon OVA aerosol challenge. In contrast, airway infection at the time of OVA sensitization predisposed for AAD that was characterized by airway inflammation, IgE secretion, thickening of airway epithelia, and goblet cell hyperplasia. This AAD histopathology was associated with a T helper type 2 (Th2) transcription profile in the lungs, including IL-4, IL-5, IL-9, and IL-25, known inducers of Th2-driven AAD. These symptoms were all prevented by a pre-challenge depletion of CD4+ T cells, but not of CD8+ T cells. As to the underlying mechanism, murine CMV activated migratory CD11b+ as well as CD103+ conventional dendritic cells (cDCs), which have been associated with Th2 cytokine-driven AAD and with antigen cross-presentation, respectively. This resulted in an enhanced OVA uptake and recruitment of the OVA-laden cDCs selectively to the draining tracheal lymph nodes for antigen presentation. We thus propose that CMV, through activation of migratory cDCs in the airway mucosa, can enhance the allergenic potential of otherwise poorly allergenic environmental protein antigens.

Evidence for Local and Systemic Immune Activation in Functional Dyspepsia and the Irritable Bowel Syndrome: A Systematic Review

BACKGROUND

Subtle histopathologic features such as eosinophilia and increased mast cells have been observed in functional gastrointestinal disorders (FGIDs), including functional dyspepsia (FD) and the irritable bowel syndrome (IBS). The mechanisms that drive recruitment of these cells to the gastrointestinal tract remain unexplained, largely due to the heterogeneity in phenotypes among patients diagnosed with such conditions. We aimed to systematically review the literature and collate the evidence for immune activation in FD and IBS, and where possible, detail the nature of activation.

METHODS

Seven literature databases were searched using the keywords: 'functional gastrointestinal disorder', FGID, 'functional dyspepsia', 'non-ulcer dyspepsia', 'idiopathic dyspepsia', 'irritable bowel syndrome', IBS and 'immun*'.

RESULTS

Fifty-one papers reporting discordant immune features met the selection criteria for this review. Changes in lymphocyte populations, including B and T lymphocyte numbers and activation status were reported in IBS and FD, in conjunction with duodenal eosinophilia in FD and increased colonic mast cells in IBS. Increases in circulating α4+β7+ gut-homing T cells appear to be linked to the pathophysiology of both FD and IBS. Studies in the area are complicated by poor phenotyping of patients into subgroups and the subtle nature of the immune activity involved in FD and IBS.

CONCLUSIONS

Alterations in proportions of gut-homing T lymphocytes in both FD and IBS indicate that a loss of mucosal homeostasis may drive the symptoms of FD and IBS. There is indirect evidence that Th17 responses may play a role in FGIDs, however the evidence for a Th2 immune phenotype in FD and IBS is limited. Although immune involvement is evident, large, well-characterised patient cohorts are required to elucidate the immune mechanisms driving the development of FGIDs.

Differential effect of the DRD3 genotype on inflammatory cytokine responses during abstinence in amphetamine-dependent women

Amphetamine exposure impacts on innate and adaptive immunity and DRD3 may modulate the effect of amphetamine on the immune response. We assessed the immune-cytokine markers in 72 female patients with amphetamine dependence (AD) at baseline and after 4-week drug abstinence and in 51 healthy women. Multiplex magnetic bead assay was used to measure the plasma cytokine expression level simultaneously in all participants and DRD3 rs6280 polymorphism was genotyped in patients. We demonstrated an increase of the T helper 1 (Th1) cytokines (IL-2), Th2 cytokines (IL-4, IL-5, IL-6 and IL-10) and other cytokines (IL-1β) in the entire AD cohort. A similar cytokine pattern, along with a significantly decreased IL-8 and IL-10 levels was observed after 4-week abstinence. Among AD patients with DRD3 rs6280 TT genotype, the cytokine expression profile was consistent with total AD cohort at baseline and revealed a significant down-regulated plasma level of the Th1, Th2, and other cytokines except for IL-6 after 4-week abstinence. In AD group with DRD3 rs6280 C allele carrier, we found IL-2 level was significantly higher than healthy controls at baseline and remained higher, accompanied with a borderline increase in IL-4, IL-6 and IL-1β levels after 4-week abstinence. Our results suggest that chronic use of amphetamine increased both pro- and anti-inflammatory cytokines in AD patients, indicating the immune imbalance that may persist for 4 weeks or more. Besides, DRD3 rs6280 TT genotype may be associated with favorable recovery in general inflammatory cytokines during period of abstinence.

The Foxp3+ regulatory T-cell population requires IL-4Rα signaling to control inflammation during helminth infections

Forkhead box P3 (Foxp3⁺) regulatory T (Treg)-cell function is controlled by environmental cues of which cytokine-mediated signaling is a dominant component. In vivo, interleukin-4 (IL-4)-mediated signaling via IL-4 receptor alpha (IL-4Rα) mediates Treg cell transdifferentiation into ex-Foxp3 T helper 2 (Th2) or T helper 17 (Th17) cells. However, IL-4-mediated signaling also reinforces the Foxp3 Treg compartment in vitro. We generated Foxp3-specific IL-4Rα-deficient mice and demonstrated differential efficiency of IL-4Rα deletion in male (approximately 90%) and female (approximately 40%) animals, because of cyclic recombinase (Cre)-mediated X-linked foxp3 inactivation. Irrespective of the degree of IL-4Rα deletion within the Foxp3⁺ Treg cell population, mice showed exacerbation of immune effector responses with aggravated tissue pathology in tissue-dwelling helminth infections (Schistosoma mansoni or Nippostrongylus brasiliensis). Mechanistically, IL-4Rα deletion in males and females led to a reduced expression of Foxp3 and subsequently an impaired accumulation of Foxp3⁺ Treg cells to inflamed tissues. In-depth cellular typing by flow cytometry revealed that the impairment of IL-4Rα-mediated signaling during helminth infections decreased the ability of central Treg cells to convert into effector Treg (eTreg) cells and caused a significant down-regulation of markers associated with Treg cell migration (C-X-C motif chemokine receptor 3 [CXCR3]) and accumulation in inflamed tissues (GATA binding protein 3 [GATA3]) as well as survival (B cell lymphoma 2 [Bcl-2]). These findings unprecedentedly, to our knowledge, uncover a role for IL-4Rα signaling in the positive regulation of Foxp3⁺ Treg cell function in vivo. Complementing our past knowledge on a widely reported role for IL-4Rα signaling in the negative regulation and transdifferentiation of Foxp3⁺ Treg cells in vivo, our present findings reveal the host requirement for an intact, but not reduced or potentiated, IL-4Rα-mediated signaling on Foxp3⁺ Treg cells to optimally control inflammation during helminth infections.

Host soluble mediators such as cytokines play a key role in the regulation of the immune response. Forkhead box P3 (Foxp3⁺) regulatory T (Treg) cells, which are involved in maintaining self-tolerance and immune system homeostasis, are influenced by cytokines, including interleukin-4 (IL-4). However, opposing reports have emerged on the effect of this cytokine on Treg cells. Some evidence suggests IL-4 inhibits Treg cells, whereas other studies indicate a supportive role for this cytokine in Treg cell biology and function. To unambiguously address this question, we generated mice with IL-4 receptor specifically removed from the Treg cell population. Our newly generated mice did not show any sign of spontaneous inflammation during homeostasis, but when challenged with an experimental infection by parasitic worms, deletion of the IL-4 receptor from the Treg cell population led to increased inflammation and aggravated tissue pathology. Several defects such as poor activation, reduced promigratory marker expression, and reduced survival were apparent in Treg cells with impaired IL-4 responsiveness. Our evidence presents a strong case for a supportive role of IL-4 via IL-4 receptor in the biology and optimal regulatory function of Treg cells during worm infections.

Divergent lncRNA GATA3-AS1 Regulates GATA3 Transcription in T-Helper 2 Cells

Long non-coding RNAs (lncRNAs) possess a diverse array of regulatory functions including activation and silencing of gene transcription, regulation of splicing, and coordinating epigenetic modifications. GATA3-AS1 is a divergent lncRNA gene neighboring GATA3. GATA3 is considered the master regulator of TH2 lineage commitment enabling TH2 effector cells to efficiently transcribe genes encoding cytokines IL-4, IL-5, and IL-13. Here, we show that the GATA3-AS1 lncRNA is selectively expressed under TH2 polarizing conditions and is necessary for efficient transcription of GATA3, IL5, and IL13 genes, while being sufficient for GATA3 transcription. GATA3-AS1 is required for formation of permissive chromatin marks, H3K27 acetylation and H3K4 di/tri-methylation, at the GATA3-AS1-GATA3 locus. Further, GATA3-AS1 binds components of the MLL methyltransferase and forms a DNA-RNA hybrid (R-loop) thus tethering the MLL methyltransferase to the gene locus. Our results indicate a novel regulatory function for a divergent lncRNA and provide new insight into the function of lncRNAs in T helper cell differentiation.

SERMs Promote Anti-Inflammatory Signaling and Phenotype of CD14+ Cells

Signaling via estrogen receptors (ER) is recognized as an essential part of the immune regulation, and ER-mediated signaling is involved in autoimmune reactions. Especially ERα activation in immune cells has been suggested to skew cytokine production toward Th2/M2-type mediators, which can have protective effect on inflammatory diseases and reduce Th1 and Th17 responses. These effects are caused by increased alternative activation of macrophages and changes in the activation of different T cell populations. In humans, hormonal status has been shown to have a major impact on several inflammatory diseases. Selective estrogen receptor modulators (SERMs) are ER ligands that regulate ER actions in a tissue-specific manner mostly lacking the adverse effects of steroid hormones. The impact of SERMs on the immune system is less studied, but it is suggested that certain SERMs may also produce immunoprotective effects. Here, we show that two novel SERMs and raloxifene affect immune cells by promoting M2 macrophage phenotype, alleviating NFκB activity, inhibiting T cell proliferation, and stimulating the production of anti-inflammatory compounds such as IL10 and IL1 receptor antagonist. Thus, these compounds have high potency as drug candidates against autoimmune diseases.

[Research progress in the role of intestinal dendritic cells in food allergy]

Food allergy (FA) seriously affects people's quality of life, and its mechanism and effective treatment methods need further study. Intestinal dendritic cells (DCs) can recognize food allergens in FA through multiple pattern recognition receptors, which can be affected by food processing and the addition of additives. In the subsequent allergen presentation process, more and more co-stimulatory molecules have been found to be involved in the polarization of T cells to type 2 helper T cells (Th2 cells), which is facilitated by many endogenous and exogenous substances. DCs may lead to a vicious cycle in the effective phase of FA. DCs also play an important role in the establishment of food tolerance. DC-based oral immunotherapy, bacterial therapy, high-fiber diet and breastfeeding may be used in the prevention and treatment of FA in the future. It is of great significance to study the mechanism of FA and tolerance and explore the effective treatment of FA from the perspective of DCs.

Fundamental role of dendritic cells in inducing Th2 responses

A mysterious puzzle in immunology is how the immune system decides what types of immune response to initiate against various stimuli. Although much is known about control of T helper 1 (Th1) and Th17 responses, the mechanisms that initiate Th2 responses remain obscure. Antigen-presenting cells, particularly dendritic cells (DCs), are mandatory for the induction of a Th cell response. Numerous studies have documented the organizing role of DCs in this process. The present review summarizes the fundamental roles of DCs in inducing Th2 responses.

IL-4RA gene expression in PBMC with regard to place of living and atopy status

BACKGROUND

IL-4 and IL-4RA are key factors in allergic inflammation. IL-4 stimulates both IgE production and Th2 lymphocyte differentiation. Increased levels of IL-4 and IL-4RA have been shown in allergic patients. Genetic analyses have confirmed that polymorphisms within the IL-4RA gene influence the risk of allergy and can change the expression of the protein. Due to gene-environment interactions, this process is also likely to be modified by environmental exposure.

OBJECTIVES

The aim of the study was to evaluate the IL-4RA gene expression in peripheral blood mononuclear cells (PBMC) from atopic and non-atopic subjects with regard to place of living (urban vs rural).

MATERIAL AND METHODS

We enrolled 38 subjects into the study, 18 of whom were atopic. Atopy was estimated according to the results of a skin prick test. PBMC were isolated from whole blood, total RNA was extracted and reverse transcribed into cDNA. We performed real-time PCR to measure gene expression, the ACTB gene was chosen as a reference and the delta-delta Ct (ΔΔCT) method was applied for relative quantification. The Mann-Whitney U test was used for statistics.

RESULTS

We did not observe any statistically significant differences in the gene expression profile between atopic and non-atopic subjects regardless of their place of living. However, a trend was observed for atopic rural inhabitants to have lower levels of IL-4RA gene expression than atopic subjects living in the town.

CONCLUSIONS

The regulation of IL-4RA gene expression is complex and probably influenced by both genetic and environmental factors, such as farming exposures, which could provide the counterbalance to atopy.

Low-dose lymphocyte immunotherapy rebalances the peripheral blood Th1/Th2/Treg paradigm in patients with unexplained recurrent miscarriage

BACKGROUND

The published results regarding lymphocytes immunotherapy for unexplained recurrent miscarriage (uRM) patients are conflicting due to different screening criteria and therapeutic protocols. The objective of the present study is to evaluate the effectiveness of immunotherapy using low-dose lymphocytes in patients with uRM and Th1/Th2/Treg paradigm disorders.

METHODS

Sixty-four uRM patients who received low-dose lymphocytes immunotherapy served as the immunotherapy group, while the other 35 women who did not receive the treatment served as the control group. The proportions of peripheral blood Th1 cells, Th2 cells and Treg cells; and the concentration of TGF-β1 in serum were detected by flow cytometry and enzyme-linked immunosorbent assay (ELISA), respectively, before and after the immunotherapy.

RESULTS

The proportion of Th1 cells was significantly decreased while the proportions of Th2 cells and Treg cells were significantly increased in immunotherapy group patients after treatment. In addition, the concentration of TGF-β1 in serum was significantly higher after immunotherapy than before. Forty-three uRM patients achieved pregnancy after receiving immunotherapy and 5 patients underwent miscarriages in the immunotherapy group (11.6%, 5/43), while 8 of the 23 pregnant patients experienced a miscarriage in the control group (34.8%, 8/23; p < 0.05).

CONCLUSIONS

Low-dose lymphocyte immunotherapy is beneficial for restoring balance in the Th1/Th2/Treg paradigm and improving pregnancy outcome in uRM patients.

TRIAL REGISTRATION

NCT03081325 . ClinicalTrials.gov . Retrospectively registered July 2015.

Human cellular and humoral immune responses to Phlebotomus papatasi salivary gland antigens in endemic areas differing in prevalence of Leishmania major infection

Background

Sand fly saliva compounds are able to elicit specific immune responses that have a significant role in Leishmania parasite establishment and disease outcome. Characterizing anti-saliva immune responses in individuals living in well defined leishmaniasis endemic areas would provide valuable insights regarding their effect on parasite transmission and establishment in humans.

Methodology/Principal findings

We explored the cellular and humoral immune responses to Phlebotomus (P.) papatasi salivary gland extracts (SGE) in individuals living in cutaneous leishmaniasis (CL) old or emerging foci (OF, EF). OF was characterized by a higher infection prevalence as assessed by higher proportions of leishmanin skin test (LST) positive individuals compared to EF. Subjects were further subdivided into healed, asymptomatic or naïve groups. We showed anti-SGE proliferation in less than 30% of the individuals, regardless of the immune status, in both foci. IFN-γ production was higher in OF and only observed in immune individuals from OF and naïve subjects from EF. Although IL-10 was not detected, addition of anti-human IL-10 antibodies revealed an increase in proliferation and IFN-γ production only in individuals from OF. The percentage of seropositive individuals was similar in immune and naïves groups but was significantly higher in OF. No correlation was observed between anti-saliva immune responses and LST response. High anti-SGE-IgG responses were associated with an increased risk of developing ZCL. No differences were observed for anti-SGE humoral or cellular responses among naïve individuals who converted or not their LST response or developed or not ZCL after the transmission season.

Conclusions/Significance

These data suggest that individuals living in an old focus characterized by a frequent exposure to sand fly bites and a high prevalence of infection, develop higher anti-saliva IgG responses and IFN-γ levels and a skew towards a Th2-type cellular response, probably in favor of parasite establishment, compared to those living in an emerging focus.

During murine experimental leishmaniasis sand fly saliva components modulate the host immune response and facilitate infection while pre-exposition to uninfected sand fly bites is associated with a protective cellular response against subsequent infection. Human anti-saliva immune responses are not well defined in leishmaniasis endemic areas. Here, we report an analysis of anti P. papatasi saliva cellular and humoral responses in individuals residing in endemic foci showing different prevalence rates of L. major infection. Individuals were further subdivided based on LST response and presence of typical CL scars. We showed higher anti-saliva cellular and humoral responses and a skew towards a Th2 response in the old focus characterized by the highest prevalence of infection. No correlation was observed between LST and anti-saliva cellular or humoral response. We showed that high anti-saliva IgG responses constituted a risk factor for the development of CL. Our findings suggest that the anti-P. papatasi saliva cellular and humoral response profiles vary with the level of sand fly exposure and the prevalence of infection in CL endemic areas. Such studies in humans from highly endemic areas could contribute to a better understanding of the immune response to sand fly saliva and its role in leishmaniasis outcome.

1,25(OH)2D3 Protects Liver Fibrosis Through Decreasing the Generation of TH17 Cells

BACKGROUND The aim of this study was to study the effects of 1-alpha,25-dihydroxy-cholecalcifero (1,25(OH)2D3) on liver fibrosis and the generation of Th17 cells in vivo and in vitro. MATERIAL AND METHODS Thirty C57 mice were randomly divided into control, model, and treatment groups. Hepatic fibrosis was induced by subcutaneous injection of CCl4. Liver fibrosis condition was evaluated through pathological inspection and blood biochemical examination of liver function. Immunohistochemical assays were used to detect the expression of α-SMA, TGF-β, and collagen I to observe hepatic stellate cell activation level. Flow cytometry, ELISA, and RT-PCR were performed to explore the association between 1,25(OH)2D3 and Th17 cell differentiation. RESULTS Collagen I, TGF-β, and α-SMA were decreased after 1,25(OH)2D3 treatment. Consistently, RORγt mRNA and the rate of Th17 cells was significantly reduced after 1,25(OH)2D3 treatment. In vitro, the proportion of Th17 cells was also obviously reduced in the 1,25(OH)2D3 group, and mRNA levels of IL-17A, IL-22, RORγt, and RORa were significantly decrease in the 1,25(OH)2D3 group compared to the control group. CONCLUSIONS Treatment with 1,25(OH)2D3 can alleviate the damage caused by liver fibrosis. Experiments in vivo and in vitro showed that 1,25(OH)2D3 treatment deceased the rates of Th1 and Th17 cells and increased the rate of Th2 cells. The level of IL-17A, IL-22 and IFN-γ were decreased, while the level of IL-4 was increased by the treatment of 1,25(OH)2D3.

[Effect of Xinfeng Capsule on Pulmonary Function, Thi/Th2 Cells, and Regulatory T Cells of Adjuvant Arthritis Rats]

Objective To observe the effects of Xinfeng Capsule (XFC) at different doses on lung function, Thl/Th2 cells, regulatory T cells (Treg) in adjuvant arthritis (AA) rats. Methods Totally 84 rats were randomly divided into 5 groups, i.e., the normal control group (NC) , the model group (M) , the methotrexate (MTX) group, the Tripterygium Glycosides Table (TGT) group, the low dose XFC (XFC- L) group, the medium dose XFC (XFC-M) group, the high dose XFC (XFC-H) group, 12 in each group. Freund's complete adjuvant (FCA; 0. 1 mL) was intradermally injected to all rats except those in the NC group from right rear paw to induce inflammation. Medication was started from the 19th day after inflam- mation. Normal saline was administered to rats in the NC group and the M group. Rats in the rest groups were correspondingly administered with MTX, TGT, XFC, respectively. Changes of each index were ob- served in all groups. Results (1) Compared with the NC group, rat paw swelling degree (E) , arthritis index (AI) , lung index (LI) , average expiratory flow in 1 second (FEV1/FVC%) , alveolitis integral, TNF- α, Th1/Th2 cells, transforming growth factor-β₁ ( TGF-β₁ ) expression significantly increased in the M group (P <0. 01) ; forced vital capacity (FVC) , peak expiratory flow 25% of vital capacity (FEF25), peak expiratory flow 50% of vital capacity (FEF50), peak expiratory flow 75% of vital capacity (FEF75), the maximum mid-expiratory flow (MMF) , peak expiratory flow (PEF) , CD4 ⁺Treg, CD4⁺CD25 ⁺Treg, IL-10, and Foxp3 expression significantly decreased in the M group (P <0. 01). (2) Compared with the M group, body weight, FVC, FEF25, FEF50, FEF75, MMF, PEF, IL-10, Treg, and Foxp3 expression increased in all treatment groups; E, Al, LI, FEV1/FVC%, TNF-α, Th1/Th2 cells, and TGF-β₁ expression decreased in all treatment groups (P <0. 05, P <0. 01). (3) Compared with the XFC-M group, LI, alveolitis integral, TNF- α, Th1/Th2 cells, and TGF-β1 increased; FVC, FEF25, FEF50, FEF75, IL-10, CD4⁺Treg, CD4⁺CD25⁺ Treg, and Foxp3 decreased in other treatment groups (P <0. 05, P <0. 01). Conclusions AA rats had local swollen paws and decreased lung function. XFC could significantly improve paw swelling and Al of AA rats, and improve lung function. It could reduce inflammatory reaction and immune complexes on tis- sue and organ damage, improve joint and pulmonary symptoms possibly through promoting expressions of IL-10, CD4⁺Treg, CD4⁺CD25⁺Treg, and Foxp3, and inhibiting TNF-α,Th1/Th2 cells, and TGF-β₁ ex- pression.

Increased mitochondrial arginine metabolism supports bioenergetics in asthma

High levels of arginine metabolizing enzymes, including inducible nitric oxide synthase (iNOS) and arginase (ARG), are typical in asthmatic airway epithelium; however, little is known about the metabolic effects of enhanced arginine flux in asthma. Here, we demonstrated that increased metabolism sustains arginine availability in asthmatic airway epithelium with consequences for bioenergetics and inflammation. Expression of iNOS, ARG2, arginine synthetic enzymes, and mitochondrial respiratory complexes III and IV was elevated in asthmatic lung samples compared with healthy controls. ARG2 overexpression in a human bronchial epithelial cell line accelerated oxidative bioenergetic pathways and suppressed hypoxia-inducible factors (HIFs) and phosphorylation of the signal transducer for atopic Th2 inflammation STAT6 (pSTAT6), both of which are implicated in asthma etiology. Arg2-deficient mice had lower mitochondrial membrane potential and greater HIF-2α than WT animals. In an allergen-induced asthma model, mice lacking Arg2 had greater Th2 inflammation than WT mice, as indicated by higher levels of pSTAT6, IL-13, IL-17, eotaxin, and eosinophils and more mucus metaplasia. Bone marrow transplants from Arg2-deficient mice did not affect airway inflammation in recipient mice, supporting resident lung cells as the drivers of elevated Th2 inflammation. These data demonstrate that arginine flux preserves cellular respiration and suppresses pathological signaling events that promote inflammation in asthma.

Apoptosis is related to imbalance of Th1/Th2-type cytokine in peripheral blood mononuclear cells of patients with chronic hepatitis B

KEYWORDS

peripheral blood mononuclear cells; apoptosis; cytokine; hepatitis B virus.

Elevated serum leptin levels in patients with systemic lupus erythematosus

Previous studies have indicated that leptin and the soluble leptin receptor (SLR) might influence inflammatory and immune processes in autoimmune diseases, but this remains unclear in systemic lupus erythematosus (SLE). The aim of our study was to assess if leptin and SLR are involved in the etiopathology of SLE and the possible mechanism of immune regulation. We studied 87 patients with SLE and 85 matched subjects. We assessed the levels of serum leptin and SLR, tested the long isoform leptin receptor (Ob-Rb) mRNA levels in SLE patients and a control group. Furthermore, we measured Th1 and Th2 percentage in SLE patients' lymphocytes and examined lymphocytes activation and proliferation assays with leptin stimulation in vitro. The study found a higher level of serum leptin in SLE patients, however, no difference was found in serum SLR levels or Ob-Rb mRNA levels between SLE patients and the control group. The percentage of Th1 cells decreased and Th2 cells increased after treatment with glucocorticoids in SLE patients. Leptin stimulated the proliferation of T cells in vitro, and differentiation to Th1 cells increased. The present study demonstrated that leptin may play an important role in the pathogenesis of SLE, inducing dysfunction of autoimmune processes.

[The dynamic changes of tuberculosis related cytokines during disease progression]

OBJECTIVE

To study the dynamic changes of tuberculosis related cytokines among patients during the different courses of treatment, and to analyze their influences on the development and prognoses of tuberculosis.

METHODS

All patients with active tuberculosis were enrolled from Guangzhou, Shenzhen and Foshan TB control institutes. There were a total of 68 cases, 36 males and 32 females, aged 19 to 50 years [ average (30±9) years]. All the TB patients received standard chemotherapy regimen of anti-tuberculosis, and were divided into 2 groups: one completed treatment group (cured or clinically cured 38 cases) and 1 uncompleted treatment group (treatment failure or need to extend treatment, 30 cases). Peripheral blood serum at 0, 2, 6 month during the treatment from 68 tuberculosis patients were collected, and the concentration of IFN-γ,IL-4,IL-17,TGF-β,TNF-α and IL-10 were detected by ELISA tests.

RESULTS

The concentration of IFN-γ, TGF-β and IL-4 in all enrolled patients showed significant decrease (from 23.2 ng/L to 22.3 ng/L, from 169.1 ng/L to 123.2 ng/L; 65.0 ng/L to 31.9 ng/L) (t=2.67, 2.35 and 3.41, P<0.05) along with the extension of treatment. IL-10 increased significantly (12.9 ng/L) in the uncompleted treatment group but declined significantly (5.38 ng/L) (P<0.05) in the completed treatment group at the end of 6 month. Meanwhile, IL-4 decreased significantly (P<0.05) in the completed treatment group but no significant changes were observed in the uncompleted treatment group. Th1/Th2 (IFN-γ/IL-4) raised gradually in the completed treatment group (0 month <2 month <6 month, t=6.32, 6.03 and 5.85, P<0.05), while it was only at 6 month in the uncompleted treatment group (0 month <6 month, t=3.7, P<0.05). And the ratio of Th1/Th2 in the completed treatment group was significantly higher than that in the uncompleted group treatment (P<0.05).

CONCLUSION

It suggests that the changes of Th1 cytokines (IFN-γ, TGF-β) and the Th1/Th2 balance play an important role in the pathogenesis, development and prognosis of TB. The suppression of IFN-γ, TGF-β or Th1/Th2 balance may be an important factor influencing the prognosis of TB.

Current concepts in targeting chronic obstructive pulmonary disease pharmacotherapy: making progress towards personalised management

Chronic obstructive pulmonary disease (COPD) is a common, complex, and heterogeneous disorder that is responsible for substantial and growing morbidity, mortality, and health-care expense worldwide. Of imperative importance to decipher the complexity of COPD is to identify groups of patients with similar clinical characteristics, prognosis, or therapeutic needs, the so-called clinical phenotypes. This strategy is logical for research but might be of little clinical value because clinical phenotypes can overlap in the same patient and the same clinical phenotype could result from different biological mechanisms. With the goal to match assessment with treatment choices, the latest iteration of guidelines from the Global Initiative for Chronic Obstructive Lung Disease reorganised treatment objectives into two categories: to improve symptoms (ie, dyspnoea and health status) and to decrease future risk (as predicted by forced expiratory volume in 1 s level and exacerbations history). This change thus moves treatment closer to individualised medicine with available bronchodilators and anti-inflammatory drugs. Yet, future treatment options are likely to include targeting endotypes that represent subtypes of patients defined by a distinct pathophysiological mechanism. Specific biomarkers of these endotypes would be particularly useful in clinical practice, especially in patients in which clinical phenotype alone is insufficient to identify the underlying endotype. A few series of potential COPD endotypes and biomarkers have been suggested. Empirical knowledge will be gained from proof-of-concept trials in COPD with emerging drugs that target specific inflammatory pathways. In every instance, specific endotype and biomarker efforts will probably be needed for the success of these trials, because the pathways are likely to be operative in only a subset of patients. Network analysis of human diseases offers the possibility to improve understanding of disease pathobiological complexity and to help with the development of new treatment alternatives and, importantly, a reclassification of complex diseases. All these developments should pave the way towards personalised treatment of patients with COPD in the clinic.

IL-33 promotes GATA-3 polarization of gut-derived T cells in experimental and ulcerative colitis

BACKGROUND

In the respiratory mucosa, interleukin (IL)-33, has been shown to enhance T helper 2 (TH2)-type responses through the master regulatory gene GATA-3. IL-33 is upregulated in ulcerative colitis (UC), and the aim was to assess if IL-33 holds a similar key position in the shaping of the immune response in experimental colitis (piroxicam-accelerated colitis (PAC) in IL-10 (-/-) mice, dextran sodium sulfate (DSS) model) and UC.

METHODS

Colonic IL-33 expression was determined in UC (8 active UC, 8 quiescent UC, and 7 controls) and experimental colitis. Mesenteric lymph node (MesLN) T cells were isolated from PAC IL-10 (-/-) mice and stimulated with IL-33.

RESULTS

The colonic IL-33 expression was significantly upregulated all forms of colitis (P < 0.01) and correlated with disease severity score and inflammation (P < 0.001), and with GATA-3 expression levels (P < 0.01); no correlation with the TH1-specific T-bet expression was observed. MesLN T cells stimulated with IL-33 had increased GATA-3 expression, and showed an IL-33 dose-dependent increase in secreted TH2-type cytokines, whereas this effect was abolished by blocking IL-33 signaling. The non-TH2-type cytokine IL-17 was upregulated by IL-33 but in a T cell receptor dependent manner, as opposed to TH2-type cytokines, which required only IL-33 stimulation.

CONCLUSIONS

The study demonstrates that intestinal IL-33 is capable of inducing GATA-3 in mucosal T cells, and suggests that IL-33 is a key mediator of pathological TH2 and non-TH2-type responses in intestinal inflammation. Blocking IL-33 signaling could be a feasible option in the treatment of UC.