Inhibition Of IgE Production Research Articles

Chemical and biological characterization of Food Allergy Herbal Formula 2 (FAHF-2) product consistency and potency

FAHF-2 has been shown to prevent peanut-induced anaphylaxis in a murine model. Phase I trials have demonstrated that FAHF-2 is a safe treatment for patients with food allergy. To complete the ongoing phase II study of safety and efficacy of FAHF-2, several batches of FAHF-2 were generated. The aim of this study was to analyze the chemical and biological consistency of different batches of FAHF-2 using our established methods. HPLC chromatogram data of each batch of FAHF-2 product were collected for analyzing product consistency. The bioactivities of 3 different batches of FAHF-2 (batch number1106, 0909 and 0202) were analyzed by culturingU266 (human B cell myeloma cell line), RBL-2H3 (mast cell line), and RAW 264.7 (mouse macrophage cell line) in the presence of 31, 62, 125, 250, and 500 μg/ml of FAHF-2. IgE production by U266, β-hexosaminidase release by RBL-2H3, and TNF-α production by RAW 264.7 cells were determined. Untreated cells were used as controls. Three biomarkers, berberine, jatrorrhizine, and ganoderic acid D, were used as indicators of FAHF-2 batch consistency. HPLC chromatogram data showed that batches of FAHF-2 had similar peak intensities of these three biomarkers. The in vitro assays showed that different batches of FAHF-2 all significantly inhibited IgE production by B cells, TNF-α production by macrophage cells, and degranulation by mast cells. IC50 values of 3 batches were comparable in the three bioactivity assays. This study shows that different batches of FAHF-2 used in clinical trials exhibited chemical consistency and biological potency in vitro.

Mechanisms of immunotherapy to wasp and bee venom

Hymenoptera venoms are important allergens that can elicit both local and systemic allergic reactions, including life-threatening anaphylaxis. Venom immunotherapy (VIT) remains the most effective treatment, reducing the risk of systemic reactions in individuals with Hymenoptera venom allergy. VIT can restore normal immunity against venom allergens and provide patients with a lifetime of tolerance to venoms. During VIT, peripheral tolerance is induced by the generation of allergen-specific regulatory T (Treg) cells, which suppress proliferative and cytokine responses against the venom allergens. Treg cells are characterized by IL-10 secretion that directly or indirectly influence effector cells of allergic inflammation, such as mast cells, basophils and eosinophils. Treg cells also have influence on B cells, suppressing IgE production and inducing the production of blocking type IgG4 antibodies against venom allergens. An accumulating body of evidence suggests that Treg cells may affect allergen sensitization and methods for enhancing this cell population may eventually improve the efficacy of VIT. In this article, immune mechanisms enrolled in bee and wasp VIT are reviewed.

Relationship between serum levels of interleukin-18, IgE and disease severity in patients with atopic dermatitis

Interleukin (IL)-18 is a pleiotropic cytokine. Synergistically with IL-12, IL-18 promotes immune responses of the T helper type, by enhancing synthesis of interferon-γ and inhibiting IgE production. IL-18 can also enhance production of IL-4 and IL-13 production, and stimulate synthesis of IgE. Moreover, in the presence of IL-3, IL-18 can directly stimulate basophils and mast cells to produce their mediators in an IgE-independent manner. These results indicate a role for IL-18 in the pathogenesis of atopic dermatitis (AD). To examine the association of serum IL-18 with IgE levels and disease severity in patients with AD. ELISA was used to measure IL-18 and total IgE levels in the sera of 67 patients with AD and 50 healthy volunteers. The SCORing Atopic Dermatitis (SCORAD) tool was used to determine the severity of this disease. The mean serum level of IL-18 in study group (155.68 pg/mL) was significantly higher than that of controls. IL-18 was also significantly higher in the sera of the patients with severe AD than in those with milder disease. There was a correlation with IgE and IL-18 levels, as patients who had high IgE levels also had high IL-18 levels, compared with controls. IL-18 seems to play an important role in the pathogenesis of AD, but this requires further study. IL-18 could be a useful clinical marker of disease severity in AD.

Modulation of immunoglobulin production by invariant Vα19-Jα33 TCR-bearing cells.

We have previously shown that invariant Vα19-Jα33 TCR+ (Vα19i T) cells suppress the disease progress in some models for organ specific autoimmune diseases and type IV allergy that deteriorate along with decline to excess in Th1- or Th17- immunity. In this study, we examined the effects of over-generation of Vα19i T cells on the Th2-controlled immunoglobulin isotype production in the models for type I allergy. IgE production by invariant Vα19-Jα33 TCR transgenic (Tg) mice was suppressed compared with that by non-Tg controls following administration with goat anti-mouse IgD antiserum or OVA, while IgG2a production was not influenced by the introduction of the transgene into the recipients. IgE production by wild type mice was similarly reduced when they were subjected to adoptive transfer with invariant Vα19-Jα33 TCR Tg+ but not Tg− cells prior to immunization. Furthermore, the suppression of IgE production by these recipients was enhanced when they were previously administered with a Vα19i T cell activator, one of the modified α-mannosyl ceramides. In summary, it is suggested that Vα19i T cells have potential to participate in the homeostasis of immunity and that they suppress disease progression resulting from not only Th1- but also Th2- immunity excess.

Extract of Poncirus trifoliata fruit reduces elevated serum IgE concentrations in chemically induced allergic model mice

The fruit of trifoliate orange (Poncirus trifoliate) is widely used for treating allergies including allergenic dermatitis and inflammation in oriental medicine. Increased blood IgE concentration and histamine level following dermatitis, coughing and asthma are the most important clinical symptoms of allergic diseases. Decreases in the elevated serum IgE concentrations are essential in the treatment of allergy because increased IgE blood levels are initiated in allergenic immune disorders. This study was conducted to investigate the activities of an extract of trifoliate orange fruit using 100% methanol followed by extraction with boiling water on the regulation of blood IgE concentration in the U266B1 human myeloma cell line and a 1-chloro-2,4-dinitrobenzene (DNCB) sensitized mouse model. The results revealed that the extracts of trifoliate orange suppressed IgE production in U266B1 cells in a dose dependent manner with or without lipopolysaccharide (LPS) stimulation of the cells. In addition, chemically elevated blood IgE concentrations were dramatically decreased by oral administration, ventral injection, and topical application of the trifoliate orange extracts (TOE). The results indicated that the fraction of TOE should contain an important compound of the fruit of trifoliate orange, and TOE had the ability to reduce IgE concentrations in cultured cells and a chemically sensitized in vivo mouse model.

1,25-dihydroxyvitamin D3 impairs NF-κB activation in human naïve B cells

1α,25-dihydroxyvitamin D3 (calcitriol), the bioactive metabolite of vitamin D, modulates the activation and inhibits IgE production of anti-CD40 and IL-4 stimulated human peripheral B cells. Engagement of CD40 results in NF-κB p50 activation, which is essential for the class switch to IgE. Herein, we investigated by which mechanism calcitriol modulates NF-κB mediated activation of human naïve B cells. Naïve B cells were predominantly targeted by calcitriol in comparison with memory B cells as shown by pronounced induction of the VDR target gene cyp24a1. Vitamin D receptor activation resulted in a strongly reduced p105/p50 protein and mRNA expression in human naïve B cells. This effect is mediated by impaired nuclear translocation of p65 and consequently reduced binding of p65 to its binding site in the p105 promoter. Our data indicate that the vitamin D receptor reduces NF-κB activation by interference with NF-κB p65 and p105. Thus, the vitamin D receptor inhibits costimulatory signal transduction in naïve B cells, namely by reducing CD40 signaling.

Inhibition of IgE Production By Chemical Constituents Isolated From Qumai (Dianthus Superbus)

RATIONALE: It has been found that non-polar acidic fraction of Qu Mai (Dianthus superbus), which contains mostly organic acid compounds, effectively reduced IgE secretion by human B cell line (U266myeloma cells). The aim of this study was to isolate individual constituent from the Qu Mai non-polar acidic fraction, characterize these compounds, and investigate their effects on IgE secretion.

Tetragenococcus halophilus MN45 Isolated from Miso Inhibits IgE Production

We measured the ability of 100 strains of lactic acid bacteria (LAB) isolated from miso to induce Th1-type cytokines (interleukin (IL)-12 and IFN-γ) using mouse Peyer’s patch (PP) cells, and selected Tetragenococcus halophilus MN45 strain (MN45) as the strain with the potential for a strong anti-allergic effect. MN45 cultured in medium containing 15% NaCl for more than 2 days showed the strongest activity of Th1-type cytokine induction among MN45 cultured at various NaCl concentrations and culture times. Next, we analyzed the ability of MN45 to suppress IgE production and the mechanism thereof by neutralizing IL-12 and IFN-γ using PP cells and splenocytes from ovalbumin (OVA)-induced allergic diarrhea model mice. Analysis revealed that MN45 induced IL-12 first, and then IL-12 induced IFN-γ strongly and inhibited IgE production. These results indicate that MN45 may exert an anti-allergic effect.

Fucoidan suppresses IgE production in peripheral blood mononuclear cells from patients with atopic dermatitis

We previously reported that fucoidan, a dietary fiber purified from seaweed, inhibited IgE production in B cells from mice spleen in vitro and ovalbumin-sensitized mice in vivo. In this study, we examined the effect of fucoidan on IgE production in human peripheral blood mononuclear cells (PBMC) in vitro. PBMC, obtained from healthy donors or patients with atopic dermatitis (AD) with high levels of serum IgE, were cultured with IL-4 and anti-CD40 antibody in the presence or absence of fucoidan. Fucoidan significantly reduced IgE production in PBMC without affecting cell proliferation and IFN-γ production. Fucoidan also inhibited immunoglobulin germline transcripts of B cells in PBMC, and decreased the number of IgE-secreting cells. The inhibitory effects of fucoidan were similarly observed for both PBMC from patients with AD and those with healthy donors. Our findings indicate that fucoidan suppresses IgE induction by inhibiting immunoglobulin class-switching to IgE in human B cells, even after the onset of AD.

Targeting the vitamin D receptor inhibits the B cell‐dependent allergic immune response

1α,25-dihydroxyvitamin D(3) (calcitriol), the biologically active form of vitamin D, is an immunomodulatory hormone, e.g. it inhibits IgE synthesis in B cells. As its clinical application is limited by hypercalcemia, synthetic vitamin D receptor (VDR) agonists that mediate immunomodulatory activities without adverse hypercalcemic effects are of great interest. This study aimed to investigate the impact of a low-calcemic VDR agonist on the IgE immune response in vitro and in vivo. Human peripheral B cells were cultured under IgE inducing conditions in the presence of VDR ligands. B cells were analyzed by quantitative RT-PCR, enzyme-linked immunosorbent assays, enzyme-linked immunospot technique, and flow cytometry. BALB/c mice were sensitized with ovalbumin (OVA)/alum followed by the therapeutic VDR agonist treatment and analyzed regarding the humoral immunoglobulin profile. The natural VDR ligand calcitriol, but also a low-calcemic VDR agonist, profoundly suppressed IgE production by human peripheral B cells by 63.9 ± 5.9%. The potential mechanisms involved are the reduction of the transcript for activation-induced deaminase (AID) and the reduction of IgE immunoglobulin-secreting cells by 68.1 ± 12.7%. By using an in vivo approach, we finally demonstrate that the humoral IgE response in a type I allergy mouse model was impaired by the VDR agonist. Our results show that targeting the VDR modulates the humoral immune response including IgE. Whether it might be useful for clinical applications has to be determined in appropriate clinical trials.

Vitamin D receptor binds to the ε germline gene promoter and exhibits transrepressive activity

Recently, an increased incidence of allergic diseases has been associated with vitamin D deficiency. We demonstrated previously that calcitriol, the active form of vitamin D, inhibits ε germline transcription, a prerequisite for IgE production. However, the underlying mechanisms remain unexplored. We sought to investigate whether the ε germline gene promoter (Iε) represents a primary vitamin D receptor (VDR) target. Therefore we investigated VDR binding to Iε, analyzed VDR-complex composition in more detail, and delineated its functional consequences. The VDR binding to Iε in human B cells, the composition of the VDR-recruited complex, and the acetylation pattern were investigated by means of chromatin immunoprecipitation. The calcitriol-mediated action on Iε was analyzed by using a reporter gene assay. We demonstrate that Iε is a possible VDR target. Calcitriol-activated VDR binds together with retinoid X receptor α to the Iε region. The heterodimer interacts with silencing mediator for retinoid and thyroid hormone receptors, which recruits histone deacetylase (HDAC) 1 and HDAC3. The inhibition of silencing mediator for retinoid and thyroid hormone receptors or HDACs reversed the site-specific deacetylation of histones 3 and 4 and the calcitriol-driven inhibition of the ε germline transcription. The VDR-complex transrepressive actions on Iε were confirmed in a reporter assay. We show here that inhibition of IgE production by calcitriol is mediated by its transrepressive activity through the VDR-corepressor complex affecting chromatin compacting around the Iε region. Our findings shed new light on mechanisms of VDR transrepression and understanding of IgE regulation.

Proteose Peptone Fraction of Bovine Milk Depressed IgE Productionin Vitroandin Vivo

Proteose peptone (PP) is a heat-stable and acid-soluble protein in milk whey. We reveal in this study the IgE production-suppressing activity of the PP fraction in bovine milk. The PP fraction suppressed IgE production by human myeloma cell line U266 cells by depressing the IgE mRNA expression. The suppressive activity of the PP fraction was facilitated by trypsin digestion. An oral administration of the PP fraction significantly decreased the levels of total and ovalbumin (OVA)-specific IgE in the serum collected from OVA-sensitized mice. However, the serum levels of other Ig classes in OVA-sensitized mice were not affected by the intake of the PP fraction. The PP fraction suppressed the mRNA expression level of IgE in mice splenocytes collected from OVA-sensitized mice. Moreover, the B cell population in the spleen was decreased, while the T cell population was increased by administering the PP fraction. These results suggest that the PP fraction modified the B/T cell balance.

Inhibition of IgE production by docosahexaenoic acid is mediated by direct interference with STAT6 and NFκB pathway in human B cells

Nutrition can modify the onset or severity of diseases and recent changes in eating habits are supposed to promote immunoglobulin (Ig) E-dependent disorders. The n-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) possesses immunomodulatory properties and has been shown to influence chronic and allergic inflammatory disorders in vivo. Here, we examined the impact of DHA on primary human B cells to elucidate its potential role in direct regulation of IgE production and the underlying mechanisms of action. Therefore, cells were stimulated with anti-CD40/interleukin (IL)-4 in the presence of DHA. Subsequently, Ig production, generation of antibody secreting cells, epsilon-germline transcript (ɛGLT) and activation induced desaminase (AID) expression as well as IgE relevant signaling pathways were analyzed. Our results reveal that DHA inhibits IgE production (75±14%) and, depending on concentration, the differentiation of IgE secreting cells (59±27%). The reduction of IgE is accompanied by a direct inhibition of the switching process indicated by decreased ɛGLT and AID transcription. DHA causes both a reduced CD40 dependent nuclear factor κB-p50 translocation into the nucleus and a decreased IL-4 receptor expression which was associated with a reduction of IL-4 driven signal transducer and activator of transcription 6 phosphorylation. Taken together, DHA inhibits IgE production of human B cells by direct interference with both the CD40 and the IL-4 signaling pathway. The data provide one explanation for the anti-allergic role of DHA at the molecular level.

Antigen dose‐dependent suppression of murine IgE responses is mediated by CD4−CD8− double‐negative T cells

The IgE response against protein antigens is profoundly influenced by the dose used for sensitization. The aim of the study was to identify immune cells that are involved in antigen dose-dependent regulation of IgE formation. Wild-type mice as well as T helper (Th)1-deficient IL-12p40(-/-) and IFN-gamma(-/-) mice were immunized by repeated intraperitoneal injection of either low doses (K01 mice) or high doses (K100 mice) of keyhole limpet haemocyanin adsorbed to aluminium hydroxide. Splenocytes of immunized mice were restimulated in vitro and antigen-dependent T cell proliferation and cytokine production were measured. The frequency of regulatory T cell subsets among splenocytes from K01 and K100 mice was compared using fluorocytometry and RT-PCR analysis. Splenocytes or T cell subpopulations were transferred into naïve mice and the effect of lymphocyte transfer on IgE production after priming of recipients with low antigen doses was determined. Specific IgE production was considerably impaired in K100 mice. Antigenic restimulation revealed hypoproliferation of K100 splenocytes and reduced production of Th2 cytokines IL-4, IL-5 and IL-13, but no induction of IFN-gamma production. Moreover, lymphocytes from K01 and K100 mice did not show significant differences in the expression of molecules associated with the phenotype or activity of conventional regulatory T cells. Transfer of splenocytes or purified T cells from K100 mice substantially suppressed the induction of IgE production in the recipients in an antigen- and isotype-specific manner. Neither CD4(+) nor CD8(+) T cells from K100 mice were able to inhibit IgE formation; instead, we identified CD4(-)CD8(-) double-negative T cells (dnT cells) as the principal T cell population, which potently suppressed IgE production. Our data demonstrate that CD4(-)CD8(-) dnT cells play a major role in the regulation of IgE responses induced by high antigen doses.

Pediococcus pentosaceusSn26 Inhibits IgE Production and the Occurrence of Ovalbumin-Induced Allergic Diarrhea in Mice

We investigated the anti-allergic effect of a new strain (Pediococcus pentosaceus Sn26, the Sn26 strain) among 59 strains isolated from Japanese fermented vegetable pickles, the Sunki pickle. The Sn26 strain increased Th1 type cytokine (IL-12 and IFN-gamma) production of Peyer's patch (PP) cells in BALB/c mice, improved the Th1/Th2 balance, and inhibited IgE production of splenocytes of ovalbumin (OVA)-induced allergic diarrheic mice. Next we demonstrated, by neutralizing IL-12 and IFN-gamma, that the Sn26 strain first induced IL-12, that IL-12 induced IFN-gamma, and that decreases in IL-4 and IgE production followed. Furthermore, oral administration of the Sn26 strain decreased serum OVA-specific IgE levels and ameliorated the appearance of diarrhea in OVA-induced allergic diarrheic mice. Based on these results, it was assumed that oral administration of the Sn26 strain ameliorated type-1 allergies through improvement of the Th1/Th2 balance and decreases in IgE production.

Derp2-mutant gene vaccine inhibits airway inflammation and up-regulates Toll-like receptor 9 in an allergic asthmatic mouse model

A DNA vaccine encoding the whole segment of the Derp2 allergen could prevent allergic airway inflammation in a Derp2 allergen-induced allergic airway inflammation mouse model. This study investigated the effect of DNA vaccine encoding Derp2-mutant gene in which an IgE epitope was deleted on airway inflammation and the role of TLR9 in the asthmatic mouse model. A Derp2-mutant DNA vaccine was constructed. Mice were immunized, sensitized and challenged. Airway inflammation, airway hyper reactivity (AHR) and serum antibody were tested. The expression of Toll like receptor9 (TLR9) was detected with western-blot and immunehistochemistry. We demonstrated that the Derp2-mutant-DNA induced IgG2a and inhibited IgE production, inhibited airway allergenic inflammation and AHR. Derp2-mutant-DNA vaccine induce TLR9 expression in lung tissue. The data indicate that allergen DNA vaccine deleted IgE epitope could prevent allergenic airway inflammation, AHR, and upregulate lung TLR9 express.

Identifications of inhibitors of IgE production by human lymphocytes isolated from ‘Cha Chuukanbohon Nou 6’ tea leaves

Tea (Camellia sinensis L.) is consumed all over the world and in especially large quantities in Japan and China, where it has been used not only as a daily beverage but also for medicinal purposes for thousands of years. Tea has been found to exhibit various bioregulatory activities, including antiallergic, anticarcinogenic, antimetastatic, antioxidative, antihypertensive, antihypercholesterolemic, anti-dental caries and antibacterial effects, and to influence intestinal flora. Cha Chuukanbohon Nou 6 is a tea cultivar improved by the National Institute of Vegetable and Tea Science (NIVTS) in Japan. On comparing chemical constituents of 11 varieties of tea leaves by high-performance liquid chromatography, we found two new major compounds in Cha Chuukanbohon Nou 6. Nuclear magnetic resonance spectroscopy revealed these compounds to be theogallin and 1,2-di-O-galloyl-4,6-O-(S)-hexahydroxydiphenoyl-beta-D-glucopyranose. The two were similar in chemical structure to strictinin, an inhibitor of immunoglobulin (Ig) production. Thus their effects on the production of Igs by peripheral blood lymphocytes were tested. Both compounds, like strictinin, inhibited IgE production. The results suggest Cha Chuukanbohon Nou 6 to be the basis of an antiallergic beverage.

White Sorghum (Sorghum bicolor(L.) Moench) Bran Extracts Suppressed IgE Production by U266 Cells

Sorghum, Sorghum bicolor (L.) Moench, is the fifth most important cereal crop in the world. In this study, we identified the IgE production-suppressing activity of white sorghum bran extracts. White sorghum is one of the genotypes of sorghum. White sorghum bran extracts in 10 mM sodium phosphate buffer (pH 7.4) suppressed IgE production in human myeloma cell line U266. The extracts suppressed IgE production by decreasing mRNA transcription level of IgE, but they did not affect IgA or IgG production of mice splenocytes in vitro. Heat treatment and trypsin digestion did not affect IgE production-suppressing activity. The white sorghum bran extracts were fractionated by ultrafiltration, and the molecular weight of the active substance was estimated to be less than 1,000.

Anti-Allergic Effect of a Hot-Water Extract of Quince (Cydonia oblonga)

We examined the effect of a crude hot-water extract (HW) of quince (Cydonia oblonga Miller) fruit on type I allergy in vivo and in vitro. The oral administration of the quince HW-added diet to NC/Nga mice for 63 d showed a significant decrease in the development of atopic dermatitis-like skin lesions under conventional conditions. The concentration of IgE in the serum collected from mice fed with quince HW was also lowered in a dose-dependent manner. Moreover, we found that quince HW inhibited the release of beta-hexosaminidase from rat basophilic leukemia cell line RBL-2H3 after a 24-h treatment. The quince HW fraction of less than 3 kDa reduced the mRNA expression of the high-affinity IgE receptor (FcepsilonRI) gamma subunit. These results suggest that quince HW had an inhibitory effect on type I allergy by suppressing IgE production and IgE-mediated degranulation.

Peritoneal injection of fucoidan suppresses the increase of plasma IgE induced by OVA-sensitization

We previously reported that fucoidan, a dietary fiber purified from seaweed, inhibited IgE production by B cells in vitro. In this study, we examined the effect of fucoidan on IgE production in vivo. The OVA-induced increase of plasma IgE was significantly suppressed when fucoidan was intraperitoneally, but not orally, administered prior to the first immunization with OVA. The production of IL-4 and IFN-γ in response to OVA in spleen cells isolated from OVA-sensitized mice treated with fucoidan in vivo was lower than that from mice treated without fucoidan. Moreover, the flow cytometric analysis and ELISpot assay revealed that the administration of fucoidan suppressed a number of IgE-expressing and IgE-secreting B cells, respectively. These results indicate that fucoidan inhibits the increase of plasma IgE through the suppression of IgE-producing B cell population, and the effect of fucoidan in vivo is crucially dependent on the route and timing of its administration.