Inhibition Of IgE Production Research Articles

Oral mucosa effectively protects against peanut allergy in mice

Oral consumption of peanut products early in life reduces the incidence of peanut allergy in children. However, little is known about whether exposure via the oral mucosa alone is sufficient or whether the gastrointestinal tract must be engaged to protect against peanut allergy. We used a mouse model and examined the effects of peanut allergen administration to only the oral cavity on allergy development induced by environmental exposure. Naive BALB/c mice were administered peanut flour (PNF) sublingually, followed by epicutaneous exposure to PNF to mimic a human condition. The sublingual volume was adjusted to engage only the oral cavity and prevent it from reaching the esophagus or gastrointestinal tract. The efficacy was evaluated by examining the anaphylactic response, antibody titers, and T follicular helper cells. The mice exposed epicutaneously to PNF developed peanut allergy, as demonstrated by increased plasma levels of peanut-specific IgE and the manifestation of acute systemic anaphylaxis following intraperitoneal challenge with peanut extract. The development of peanut allergy was suppressed when mice had been given PNF sublingually before epicutaneous exposure. There were fewer T follicular helper cells in the skin-draining lymph nodes of mice that received sublingual PNF than in the mice that received PBS. Suppression of IgE production was observed with sublingual PNF at 1/10 of the intragastric PNF dose. Administration of peanut allergens only to the oral cavity effectively prevents the development of peanut allergy. The capacity of the oral mucosa to promote immunologic tolerance needs to be evaluated further to prevent food allergy.

Phosphorylated p38 MAP kinase expression by leucocytes is increased in allergic humans and associated with IgE responses.

Mitogen-activated protein kinases (MAPK) activate cascades that regulate cell proliferation, differentiation and death. Phosphorylated (phos-)p38 MAPK is a cell-signalling pathway associated with Th2 cytokine responses, which is required for immunoglobulin (Ig)E production. It is unknown whether MAPK are associated with IgE production. We examine the evidence linking p38 MAPK to inflammatory responses. Phos-p38, extracellular signal-related kinase (ERK) and c-JUN-n terminal (JNK) MAPK expression by blood leucocyte subsets and levels of serum Igs were measured in blood from adults with asthma and/or rhinoconjunctivitis (N = 28) and non-asthma (N = 10) (flow cytometry, microfluorenzymeimmunoassay). Peripheral blood mononuclear cells (PBMC) from allergic subjects were cultured for 10 days ± anti-CD40/recombinant IL-4 ± inhibitor of phos-P38. Culture supernatants were assayed for IgE (ELISA). Phos-p38 MAPK expression by all leucocyte subsets of allergic subjects was associated with serum IgE levels (p ≤ 0.01), after adjusting for cell counts, age, sex, race and smoking status (p ≤ 0.04). Leucocyte expression of phos-ERK and JNK did not correlate with IgE (p = 0.09-0.99). Instead, phos-ERK expression was associated with serum IgG. When PBMC from atopic subjects were cultured for 10 days with anti-CD40/rhIL-4, IgE levels were 26.2 ± 18 ng/mL. Inclusion of SB202190 (5-20 μg/mL), a specific inhibitor of phos-p38 MAPK, in culture suppressed IgE production in dose-dependent manner, with peak suppression obtained with SB202190 at 20 μg/mL (82.1% ± 11.8) (p = 0.0001), with virtually no cytotoxicity (<5%). Different MAPK pathways may be associated with IgE (p38) and IgG (ERK) responses. Phos-p38 MAPK can be a potential anti-allergy drug target.

Associations between vitamin D, immunoglobulin E concentrations, and obesity.

The prevalence of allergies and obesity has been increased in parallel. Low vitamin D [25(OH)D] levels have been linked to both higher body mass index (BMI) and allergies. Since the activation of the 25(OH)D receptor inhibits IgE production and 25(OH)D influences the IgE response specifically, we tested the hypothesis that circulating 25(OH)D concentrations are negatively related to circulating allergen-specific IgE concentrations distinctly in a large adult population-based study cohort. Moreover, we studied VDR gene expression in paired biopsies of abdominal subcutaneous (SAT) and visceral adipose tissue (VAT). We investigated whether magnetic resonance imaging-estimated visceral (VFM) and subcutaneous fat mass (SFM) are related to 25(OH)D levels. We found gender differences in circulating 25(OH)D and IgE concentrations. Participants with obesity showed lower 25(OH)D concentrations and higher IgE concentrations were detected in women only. Interestingly, participants with high levels of 25(OH)D are leaner and have improved glucose metabolism. In women, 25(OH)D correlate significant with VFM and SFM. VDR expression is significantly higher expressed in VAT and is positive associated with circulating 25(OH)D concentration. There was no association between serum IgE and 25(OH)D in the entire cohort. Based on these data, we could confirm that low levels of 25(OH)D are linked to higher BMI but could not prove our hypothesis because there is no relationship between 25(OH)D and IgE in adults. Women with higher BMI tend to have higher IgE levels what may have clinical relevance. The association between obesity and circulating 25(OH)D/IgE is not straightforward, and further knowledge is needed.

Inhibition of pathologic immunoglobulin E in food allergy by EBF-2 and active compound berberine associated with immunometabolism regulation.

Food allergy is a significant public health problem with limited treatment options. As Food Allergy Herbal Formula 2 (FAHF-2) showed potential as a food allergy treatment, we further developed a purified version named EBF-2 and identified active compounds. We investigated the mechanisms of EBF-2 on IgE-mediated peanut (PN) allergy and its active compound, berberine, on IgE production. IgE plasma cell line U266 cells were cultured with EBF-2 and FAHF-2, and their effects on IgE production were compared. EBF-2 was evaluated in a murine PN allergy model for its effect on PN-specific IgE production, number of IgE+ plasma cells, and PN anaphylaxis. Effects of berberine on IgE production, the expression of transcription factors, and mitochondrial glucose metabolism in U266 cells were evaluated. EBF-2 dose-dependently suppressed IgE production and was over 16 times more potent than FAHF-2 in IgE suppression in U266 cells. EBF-2 significantly suppressed PN-specific IgE production (70%, p<0.001) and the number of IgE-producing plasma cells in PN allergic mice, accompanied by 100% inhibition of PN-induced anaphylaxis and plasma histamine release (p<0.001) without affecting IgG1 or IgG2a production. Berberine markedly suppressed IgE production, which was associated with suppression of XBP1, BLIMP1, and STAT6 transcription factors and a reduced rate of mitochondrial oxidation in an IgE-producing plasma cell line. EBF-2 and its active compound berberine are potent IgE suppressors, associated with cellular regulation of immunometabolism on IgE plasma cells, and may be a potential therapy for IgE-mediated food allergy and other allergic disorders.

Formononetin isolated from Sophorae flavescentis inhibits B cell-IgE production by regulating ER-stress transcription factor XBP-1.

IgE plays an important pathologic role in most, if not all, allergic conditions. We previously showed that ASHMI (anti-asthma herbal medicine intervention) suppressed IgE production in murine models of asthma and in asthma subjects. However, the active compounds in ASHMI responsible for the IgE suppression are still unknown. We sought to identify the compound(s) in ASHMI that are responsible for IgE inhibition as well as investigate the mechanisms by which the identified compound(s) decreases IgE production. The compounds in Sophorae Flavescentis were separated using Column chromatography and preparative-HPLC. The separated compounds were identified using LC-MS and 1H-NMR. U266 cells, an IgE-producing plasma cell line, were cultured with various concentrations of identified compounds. The levels of IgE production by the U266 cell were measured by ELISA. Trypan blue exclusion was used to determine the cell viability. The gene expression of XBP-1 and IgE-heavy chain was determined by RT-PCR. A single compound identified as formononetin was isolated from Sophorae Flavescentis. Formononetin significantly and dose dependently decreased the IgE production in U266 cells across a concentration range of 2-20 µg/ml (p < 0.05-0.001 vs. untreated cells) with an IC50 value of 3.43 μg/ml. There was no cytotoxicity at any tested concentration. Formononetin significantly decreased XBP-1, and IgE-heavy chain gene expression compared with untreated cells (p < 0.001). Formononetin decreased IgE production in human B cell line U266 cells in a dose-dependent fashion through the regulation of XBP-1 ER transcription. Formononetin may be a potential therapy for allergic asthma and other IgE-mediated diseases.

Oral administration of Lactiplantibacillus plantarum 22A-3 exerts anti-allergic activity against intestinal food allergy mouse models sensitized and challenged with ovalbumin

In recent years, researches on food components with anti-allergic effects have been gathering attention, because of the expectation for the establishment of a safe and effective treatment for food allergy. Previous studies have reported that Lactiplantibacillus plantarum 22A-3 (LP22A3) inhibited degranulation of mast cells and reduced IgE production. We have developed a gastrointestinal allergy system in which mice are sensitized by intraperitoneal and oral administration of OVA and then challenged by oral administration of high doses of OVA. As a result, an increase in the amount of IgE in the blood and a decrease in the temperature of the colon were confirmed, and it was clarified that food allergy was induced by oral administration of high dose of OVA as the challenge. Oral administration of LP22A3 ameliorated allergic responses significantly by reducing the amount of IgE in the blood and to recovered the decrease of rectal temperature. However, LP22A3 did not affect the intestinal barrier function. Administered LP22A3 significantly suppressed mRNA expression of OX40L and IL-4. These results suggested that LP22A3 suppressed Th2 differentiation and IL-4 production via downregulation of OX40L, and consequently suppressed IgE production. LP22A3 might provide a safe and effective treatment for allergic diseases due to ability modulating intestinal immune system.

Anti-IgE effect of small-molecule-compound arctigenin on food allergy in association with a distinct transcriptome profile.

Excessive production of IgE plays a major role in the pathology of food allergy. In an attempt to identify anti-IgE natural products, Arctium Lappa was one of the most effective herbs among approximately 300screened medicinal herbs. However, little is known about its anti-IgE compounds. To identify compounds from Arctium Lappa for targeted therapy on IgE production and explore their underlying mechanisms. Liquid-liquid extraction and column chromatographic methods were used to purify the compounds. IgE inhibitory effects were determined on IgE-producing human myeloma U266 cells, peanut-allergic murine model and PBMCs from food-allergic patients. Genes involved in IgE inhibition in PBMCs were studied by RNA sequencing. The main compounds isolated were identified as arctiin and arctigenin. Both compounds significantly inhibited IgE production in U266 cells, with arctigenin the most potent (IC50=5.09μg/mL). Arctigenin (at a dose of 13mg/kg) markedly reduced peanut-specific IgE levels, blocked hypothermia and histamine release in a peanut-allergic mouse model. Arctigenin also significantly reduced IgE production and Th2 cytokines (IL-5, IL-13) by PBMCs. We found 479 differentially expressed genes in PBMCs with arctigenin treatment (p<.001 and fold-change ≥1.5), involving 24gene ontology terms (p<.001, FDR <0.05); cell division was the most significant. Eleven genes including UBE2C and BCL6 were validated by qPCR. Arctigenin markedly inhibited IgE production in U266 cells, peanut-allergic murine model and PBMCs from allergic patients by down-regulating cell division, cell cycle-related genes and up-regulating anti-inflammatory factors.

Anti-inflammatory roles of interleukin-35 in the pathogenesis of Japanese cedar pollinosis.

BackgroundInterleukin (IL)-35 has been recently identified as an anti-inflammatory cytokine in allergic inflammation. However, its biological role in the pathogenesis of allergic rhinitis has not been fully elucidated.ObjectiveThe purpose of this study was to investigate the anti-inflammatory activity of IL-35 in the pathogenesis of allergic rhinitis in patients with Japanese cedar pollinosis (JCP).MethodsPeripheral blood mononuclear cells were collected from healthy controls and JCP patients during the off-season for pollen. Peripheral blood mononuclear cells were incubated with Cry j 1, a major allergen of Japanese cedar pollen and production of IL-5, IL-13, and IL-35 were measured by enzyme-linked immunosorbent assay. Th2 (CD4+ST2+) cells and group 2 innate lymphoid cells were isolated from peripheral blood mononuclear cells of JCP patients, and the inhibitory effects of IL-35 on cell differentiation, proliferation and mRNA expression of IL-5, IL-13, and GATA3 were examined. B cells were also isolated and the effects of IL-35 on total IgE production were examined.ResultsCry j 1-induced production of IL-5 and IL-13 was significantly increased in peripheral blood mononuclear cells from JCP patients, whereas Cry j 1-induced IL-35 production was significantly decreased compared with healthy controls. IL-35 significantly inhibited Th2 cell differentiation, group 2 innate lymphoid cell proliferation, and mRNA expression of IL-5, IL-13, and GATA3 in Th2 cells and group 2 innate lymphoid cells. IL-35 also inhibited IgE production from B cells.ConclusionIL-35 is an important anti-inflammatory cytokine in JCP, and its biological roles include the downregulation of Th2 cells and group 2 innate lymphoid cells, and the inhibition of IgE production from B cells. These findings demonstrate that IL-35 may have the potential to exert anti-allergic effects for the treatment of allergic rhinitis.

Development of an ultra-performance liquid chromatography-electrospray ionization-Orbitrap mass spectrometry method for determination of xanthopurpurin in rat plasma and its application to pharmacokinetic study.

A rapid and sensitive method was developed and validated for the quantitative determination of xanthopurpurin (XPP) in rat plasma using ultra-performance liquid chromatography-electrospray ionization-Orbitrap mass spectrometry. XPP inhibits IgE production and prevents peanut-induced anaphylaxis. The XPP and emodin (internal standard) were determined in negative ion mode with m/z 239.0350 → 211.0400 and 269.0455 → 241.0507, respectively. The separation process was achieved using an ACQUITY UPLC HSS T3 column with acetonitrile and 0.1% formic acid in water (85:15). The linear range was 0.5-100 ng/mL, and the correlation coefficient (r2 ) was > 0.993. The inter-day and intra-day precision was within an acceptable range of 15%. The extraction recovery and matrix effect were 78.9-87.2% and 94.3-98.5%, respectively. Under different conditions, the XPP was stable in the range of 5.6-10.6%. This method was successfully applied to study the pharmacokinetics of XPP with an oral dose of 10.0 mg/kg and intravenous dose of 2.0 mg/kg in rats. The absolute oral bioavailability of XPP was 4.6%.

Abstract 1863: Identification of anticancer agent from antiallergic treatment regimens of traditional Chinese medicine

Abstract Traditional Chinese Medicine (TCM) is a holistic system that has been widely used in the treatment of allergy, and several specific herbal formulations have been used as treatment agents. One such compound, berberine, is a plant alkaloid isolated from Phellodendri chinensis. Berberine has been widely used in both Chinese and Ayurvedic medicine and has antimicrobial and antiprotozoal properties. Additional pharmacologic actions reported include anticancer activity as well as anti-inflammatory effects, specifically suppression of proinflammatory cytokines such as tumor necrosis factor (TNF)-alpha. Berberine has been shown to inhibit IgE production in myeloma cell line U266 without cytotoxicity. In U266 berberine inhibits nuclear translocation of NFκB by dampening phosphorylated IκB expression, subsequently decreasing activation of the ϵ-germline transcript promoter and suppressing IgE synthesis. Since this pathway plays a crucial role in many aspects of tumorigenesis, we hypothesized that this could have anticancer activity in solid tumors, specifically melanoma and anaplastic thyroid cancer (ATC). Melanoma and thyroid cancer are diagnosed with a high incidence, increasing over the last few decades. Newer therapies being evaluated in melanoma and thyroid cancer include checkpoint inhibitors. These therapeutic modalities, like others, have off target effects and high relapse rates due to acquired resistance. To identify safer alternative therapeutic strategies we characterized berberine for its anticancer properties through an in vitro proliferation assay with XTT on three melanoma cell lines (SKMEL28, SKMEL37, and SKMEL103), four ATC cell lines (T238, SW1736, HTh74, and 8505C), and three papillary thyroid cancer cell lines (TPC1, BCPAP, and K1). These cell lines were treated with 2μM berberine for 24 hrs. Berberine inhibited cellular proliferation in a dose and time dependent manner in all of these tumor types. ATC cell lines showed more sensitivity towards the drug compared to the other morphotypes. This is specifically significant since therapeutic options for ATC are extremely limited. Both ATC and melanoma have a high nuclear NFκB level, potentially contributing towards their aggressive phenotype. Cells were treated with 2μM berberine and expression of cyclinD1, CDK2, Bcl2, TRAF1, TRAF2 and IAP were evaluated by western blot. Berberine showed a differential regulation of these molecules in melanoma and thyroid cancer. This study opens up a new avenue for the adjuvant treatment of these malignancies using naturally occurring compounds. Citation Format: Tara Jarboe, Michelle Carnazza, Sanjukta Chakraborty, Nan Yang, Kamal Srivastava, Jan Geliebter, Raj K. Tiwari, Xiu-Min Li. Identification of anticancer agent from antiallergic treatment regimens of traditional Chinese medicine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1863.

Allergen immunotherapy improves defective follicular regulatory T cells in patients with allergic rhinitis

The function of follicular regulatory T (TFR) cells, especially in regulating IgE production in patients with allergic diseases, is poorly understood. We sought to investigate the phenotype, function, and clinical relevance of TFR cells in patients with allergic rhinitis (AR). The phenotype and frequency of tonsillar and circulating TFR cells were characterized by using flow cytometry. TFR cell function was examined in an assay by coculturing with follicular helper T cells and B cells. The associations between TFR cells and the clinical features in patients with AR before and after allergen immunotherapy (AIT) were analyzed. TFR cells were detected in germinal centers of tonsils, but compared with subjects without AR, the frequencies decreased in patients with AR who were allergic to house dust mites. Circulating TFR cells in blood were phenotypically and numerically correlated with tonsillar TFR cells, and a reduction of circulating TFR cells but not total or CXCR5- regulatory T cells was noted in patients with AR compared with healthy control subjects. Moreover, circulating TFR cells in patients with AR showed a specific defect in suppressing IgE production but were capable of suppressing production of other immunoglobulin types. We identified negative associations of circulating TFR cell frequencies and function with antigen-specific IgE levels or disease severity in patients with AR. After AIT, the frequencies and function of circulating TFR cells were improved, which positively associated with disease remission. Impairment in TFR cells might contribute to aberrant IgE production in patients with AR, and AIT improves defective TFR cell function. TFR cells might serve as a potential biomarker to monitor clinical response to AIT.

Alkali-soluble pectin suppresses IgE production in human myeloma cell line in vitro

We found that strawberry (Fragaria x ananassa) extract has an IgE production suppressive activity and its oral administration improved skin manifestation in atopic dermatitis model mice. In present study, we identified an active substance using the IgE-producing human myeloma cell line U266. Gel filtration experiment indicated that the IgE suppressor was more than 6kDa in molecular size. In addition, its pectinase treatment inhibited the activity, suggesting that the active substance in strawberry extract is pectin. Among solutions of water-(WP), hexametaphosphate-(HXP), acid-(HP) and alkali soluble pectin (OHP) extracted from strawberry, only OHP suppressed IgE production, and their suppressive activity was cancelled by pectinase treatment. In addition, OHP extracted from apple also inhibited IgE production. Furthermore, OHP also suppressed IgE production and did not affect IgG and IgM production in human peripheral blood mononuclear cells in an in vitro immunization condition. From these results, we concluded that OHP was an IgE suppressor in strawberry extract.

P060A MICA typing by NGS revealed the association of MICA GENE polymorphism with specific IgE production in cedar pollen allergy

Aim We have found the association of Japanese Cedar Pollinosis (JCPsis) with SNPs near MICA gene by SNPs typing in HLA gene region. In this study, the association was clarified by MICA gene typing using amplicon sequenceing method by NGS. Methods DNAs from 178 JCPsis patients, 185 healthy controls were tested allele types of MICA and HLA by HLA and KIR typing Kit (Scisco Genetics Inc) on MiSeq (Illumina Inc,). Serum samples from them were titrated for the presence of specific IgE antibodies to Japanese cedar pollen(JCP), orchard grass pollen, mugwort pollen, & house dust mite by radioallergosorbent test. Results Though all controls were selected not to have any symptom of pollinosis, only 101 in 185 individuals were specific IgE negative to all allergens tested, and 84 individuals were positive to one or more allergens including JCP. Therefore, the control group was divided into two groups, specific IgE negative and positive to allergens. The significant association of MICA with JCPsis was found only in analysis using IgE negative control group. IgE positive control group showed no association. MICA*008((P = 0.0036, odds = 0.5) & MICA*027 (P = 0.016, odds = 0.55) showed strong reverse association. Conclusions MICA*008 is lacked a part of trans-membrane region and produce soluble protein. Furthermore, 008 and 027 has the haplotype of 175Gly, 213 Ile, 251Arg which are reported to relate with MICA shedding. This haplotype associate with JCPsis strongly (P = 0.0000399, Odds = 0.46). It is speculated that soluble MICA may suppress IgE production by binding NKG2D and inactivating NK cell, and suppress pollinosis. This speculation is also supported by the report that NKG2D is critical for allergy.

Serum 25-hydroxyvitamin-D level and atopic dermatitis severity in children

Background Vitamin D plays an important role in the immune system. It inhibits B-lymphocyte proliferation and modulates the humoral response to suppress IgE production. Studies on the relationship between serum 25-hydroxyvitamin-D level and the severity of atopic dermatitis in several countries have had varying results.Objective To assess for a possible correlation between serum 25-hydroxyvitamin-D level and atopic dermatitis severity in children.Methods A cross-sectional study was conducted in 26 children with atopic dermatitis from September to December 2015. We evaluated the severity of disease using the Scoring of Atopic Dermatitis (SCORAD) index and measured serum 25-hydroxyvitamin-D levels. Spearman’s test was used to analyze for a correlation between serum 25-hydroxyvitamin-D level and the atopic dermatitis score in children with atopic dermatitis.Results Mean SCORAD index was 32.0 (SD 14.99) , with a range of 10.9 to 71.4. Mean serum 25-hydroxyvitamin-D level was 41.1 (SD 24.81) ng/mL, with a range of 10-137 ng/mL. There was a moderate correlation between serum 25-hydroxyvitamin-D level and the SCORAD index (r=-0.591), with higher SCORAD index associated with lower serum 25-hydroxyvitamin-D level (P=0.01).Conclusion There is a moderate correlation between serum 25-hydroxyvitamin-D level and the SCORAD index in children with atopic dermatitis.

Serum 25-hydroxyvitamin-D level and atopic dermatitis severity in children

Background Vitamin D plays an important role in the immune system. It inhibits B-lymphocyte proliferation and modulates the humoral response to suppress IgE production. Studies on the relationship between serum 25-hydroxyvitamin-D level and the severity of atopic dermatitis in several countries have had varying results.Objective To assess for a possible correlation between serum 25-hydroxyvitamin-D level and atopic dermatitis severity in children.Methods A cross-sectional study was conducted in 26 children with atopic dermatitis from September to December 2015. We evaluated the severity of disease using the Scoring of Atopic Dermatitis (SCORAD) index and measured serum 25-hydroxyvitamin-D levels. Spearman’s test was used to analyze for a correlation between serum 25-hydroxyvitamin-D level and the atopic dermatitis score in children with atopic dermatitis.Results Mean SCORAD index was 32.0 (SD 14.99) , with a range of 10.9 to 71.4. Mean serum 25-hydroxyvitamin-D level was 41.1 (SD 24.81) ng/mL, with a range of 10-137 ng/mL. There was a moderate correlation between serum 25-hydroxyvitamin-D level and the SCORAD index (r=-0.591), with higher SCORAD index associated with lower serum 25-hydroxyvitamin-D level (P=0.01).Conclusion There is a moderate correlation between serum 25-hydroxyvitamin-D level and the SCORAD index in children with atopic dermatitis.

Suppressive effect of ethanol extract from passion fruit seeds on IgE production

An array of foodstuffs was screened for the suppressive effect on production of IgE, a key molecule in the type I allergic reaction, using U266 cells. An ethanol extract from passion fruit seeds (PFS) has emerged as a food material with the IgE production-suppressive effect as the result of screening. Real-time RT-PCR analysis revealed that the IgE production-suppressive effect was caused by downregulated IgE gene expression. In addition, PFS selectively suppressed IgE production and did not affect the production of IgG, IgA, or IgM by mouse splenocytes. Resveratrol and piceatannol were identified as bioactive ingredients contained in passion fruit seeds. The effect of oral administration of PFS, resveratrol, and piceatannol was evaluated using a mouse model of allergic contact dermatitis. Both stilbenoids significantly suppressed IgE production in orally administered mice. Overall results indicated that passion fruit seeds are a promising candidate with the antiallergy effect for development of functional foods.

JSI-124 inhibits IgE production in an IgE B cell line

IgE is a key effector molecule in atopic diseases; however, the regulation mechanisms of IgE production in IgE B cells remain poorly understood. In the present study, we demonstrate that JSI-124 (cucurbitacin I), a selective STAT3 inhibitor, selectively inhibits production of IgE by a human IgE B cell line, CRL-8033 cells, while does not affect the IgG production by IgG B cell lines. In the aspect of molecular mechanism, we found that Igλ, but not Ighe, gene expression was suppressed by JSI-124. The above effects of JSI-124 were not mediated by affecting cellular proliferation or apoptosis. Furthermore, multiple B cell differentiation-related genes expression was not significantly affected by JSI-124. Taken together, we demonstrate a potential strategy of therapeutically suppressing IgE production without affecting IgG production in atopic patients.

Oral tolerance inhibits atopic dermatitis-like type 2 inflammation in mice by modulating immune microenvironments.

Oral tolerance is immune unresponsiveness induced by oral administration of innocuous antigens. Oral administration of allergens has been shown to be effective for suppressing IgE production in allergic responses. However, whether oral tolerance has a role in protection from allergic skin inflammation has not been fully investigated. Here, we evaluated the potential protective role of oral tolerance in a murine model of atopic dermatitis (AD) and investigated the underlying immunologic mechanisms. Mice were fed with ovalbumin (OVA) in drinking water then epicutaneously sensitized by repeated application of OVA to tape-stripped skin. Skin biopsies were analyzed for immunohistopathologic features. Levels of antibodies in sera and intestinal washes were measured by ELISA. Flow cytometry and real-time PCR analysis of the skin and mesenteric lymph nodes (MLN) were performed to investigate the immunologic effects of oral tolerance in epicutaneous (EC) sensitization-induced allergic responses. Induction of oral tolerance effectively inhibited inflammatory responses provoked by EC sensitization. Tolerogenic immune mediators were significantly increased in the skin and MLN of EC-sensitized mice following induction of oral tolerance. A marked increase in Il5 and Il13 expression and infiltration of eosinophils and type 2 innate lymphoid cells (ILC2) in the skin of EC-sensitized mice were significantly inhibited by oral tolerance. Oral tolerance plays a protective role in the development of AD in a murine model by modulating immune microenvironments to be more favorable for immune regulation. This modulation involves inhibition of ILC2 infiltration in skin lesions.

Effects of Sohamhyoong-Tang on Ovalbumin-Induced Allergic Reaction in BALB/c Mice.

IgE-mediated mast cell degranulation and excessive Th2 cells activation are major features of various allergic diseases. Sohamhyoong-tang has been reported to have anti-inflammatory and antibacterial effects. In this study, we investigated the inhibitory effect of Sohamhyoong-tang extract (SHHTE) on allergic symptoms and inflammatory responses in ovalbumin- (OVA-) sensitized BALB/c mice. The mice were sensitized with OVA and alum at 2-week intervals and then orally given SHHTE for 13 days followed by intradermal OVA injection. Administration of SHHTE significantly reduced edema formation and inflammatory-cell infiltration in ear tissues. Total and OVA-specific IgEs as well as proinflammatory cytokine TNF-α and Th2-associated cytokine IL-4 levels were lower in the SHHTE-treated group than in the vehicle. SHHTE treatment significantly suppressed both mRNA and protein levels of IL-4 and IL-5 in OVA-stimulated splenocytes. SHHTE decreased Th1 (IFN-γ) and Th17 (IL-17a) cytokine mRNA expression but increased Treg cytokines (IL-10 and TGF-β1). Moreover, SHHTE significantly inhibited degranulation of RBL-2H3 cell line in a dose-dependent manner. Thus, SHHTE efficiently inhibited the allergic symptoms in an OVA-sensitized mouse model and its action may correlate with the suppression of IgE production by increasing IL-10 and TGF-β1, which can limit the function of other T helper cells and prevent the release of inflammatory mediators from mast cells. These results suggest that SHHTE could be a therapeutic agent for treating various allergic diseases.

Specialized proresolving mediators (SPMs) inhibit human B‐cell IgE production

Specialized proresolving mediators (SPMs) constitute a recently recognized class of bioactive molecules thatpromote the resolution of inflammation. We recently reported that the SPMs resolvin D1 (RvD1) and 17-hydroxydocosahexaenoic acid (17-HDHA) promote the differentiation of IgG-secreting B cells and enhance antibody-mediated immune responses. However, there is an important knowledge gap regarding whether or not SPMs regulate human B-cell IgE production, which is the key effector in diseases such as asthma and allergy. Therefore, we investigated whether a panel of diverse SPMs influences B-cell IgE production. An important finding was that 17-HDHA and RvD1 inhibit IgE production by human B cells and suppress the differentiation of naïve B cells into IgE-secreting cells by specifically blocking epsilon germline transcript. This effect is specific to human IgE, as the SPMs do not inhibit production of IgM and IgG and did not suppress other IL-4-upregulated genes. 17-HDHA and RvD1 act by stabilizing the transcriptional repressor B-cell lymphoma 6, which competes with STAT6 for binding at the epsilon germline transcript promoter. Overall, these new findings demonstrate that certain SPMs inhibit the differentiation of IgE-producing B cells, without being broadly immune suppressive, representing a novel class of potential therapeutics for IgE-driven diseases such as asthma and allergy.