IgE peptide-specific CTL inhibit IgE production: a transient IgE suppression model in wild-type and HLA-A2.1 transgenic mice

Effect of IgE peptide-specific CTL on IgE antibody production was studied in mouse models. CTL elicited in B6.A2Kb tg mice against a human IgE peptide nonamer, pWV, lysed human IgE-secreting U266 myeloma cells and inhibit IgE production by these cells. U266 transfected with mouse A2Kb transgene (U266-A2Kb) were optimally lysed by these CTL, because the α3 domain of A2Kb interacts well with the CD8 co-receptors. The CTL generated were more effective in inhibiting IgE production by U266-A2Kb cells than lysing these cells. IgE production by and progression of U266 myeloma were suppressed in B6.A2Kb tg mice rendered tolerant to these cells and vaccinated with pWV along with CpG. We also studied the CTL response elicited in wild-type mice by a mouse nonameric IgE peptide, PI-1, along with CpG. This treatment caused a transient suppression of the IgE response in mice previously sensitized to an antigen. In mice treated with this regimen repeatedly, the IgE response was fully recovered 20 days after each treatment. Notably, while IgE peptide/CpG-treated mice remained unresponsive to antigen challenge in vivo, antigen-specific IgE production can be elicited by antigen in cultured splenocytes from these mice. Moreover, IgE peptide/CpG also inhibited an on-going IgE response, including IgE production by bone marrow cells. Taken together, these observations indicate that a CTL-based IgE peptide vaccine targeting IgE-secreting B/plasma cells may be safely employed as a therapeutic approach for suppressing IgE production.     

Effects of dietary lactosucrose (4G-beta-D-galactosylsucrose) on the IgE response in mice

In this study, we examined the effects of dietary lactosucrose (LS, a non-digestible oligosaccharide) on the IgE response in mice immunized with ovalbumin (OVA)/alum. In addition to IgG1 and IgG2a responses, the anti-OVA IgE response in mice fed LS diets was dose-dependently suppressed, as compared with the control mice, while the serum total IgG levels were comparable. Moreover, dietary LS feeding inhibited antigen-specific IgE and IgG1 productions even after a second immunization. Regarding with cytokine production, when stimulated in vitro with OVA, splenocytes obtained from LS-fed mice produced a similar level of IFN-gamma, and lower levels of IL-4 and IL-5, as compared with the control mice. But IL-10 production by OVA-stimulated splenocytes was augmented in LS-fed mice, suggesting that IL-10 producing cells are responsible for the immunoregulatory effect of LS. Our findings indicate the further possibility that dietary LS supplementation can be used to prevent IgE-mediated allergic diseases.     

Anti-inflammatory effects of mitogen-activated protein kinase kinase inhibitor U0126 in an asthma mouse model

Mitogen-activated protein kinase (MAPK) signaling cascade plays a pivotal role in the activation of inflammatory cells. Recent findings revealed that the activity of p42/44 MAPK (also known as extracellular signal-regulated kinase (ERK)) in the lungs was significantly higher in asthmatic mice than in normal controls. We hypothesized that inhibition of ERK activity may have anti-inflammatory effects in allergic asthma. BALB/c mice were sensitized with OVA and, upon OVA aerosol challenge, developed airway eosinophilia, mucus hypersecretion, elevation in cytokine and chemokine levels, up-regulation of VCAM-1 expression, and airway hyperresponsiveness. Intraperitoneal administration of U0126, a specific MAPK/ERK kinase inhibitor, significantly (p < 0.05) inhibited OVA-induced increases in total cell counts, eosinophil counts, and IL-4, IL-5, IL-13, and eotaxin levels recovered in bronchoalveolar lavage fluid in a dose-dependent manner. U0126 also substantially (p < 0.05) reduced the serum levels of total IgE and OVA-specific IgE and IgG1. Histological studies show that U0126 dramatically inhibited OVA-induced lung tissue eosinophilia, airway mucus production, and expression of VCAM-1 in lung tissues. In addition, U0126 significantly (p < 0.05) suppressed OVA-induced airway hyperresponsiveness to inhaled methacholine in a dose-dependent manner. Western blot analysis of whole lung lysates shows that U0126 markedly attenuated OVA-induced tyrosine phosphorylation of ERK1/2. Taken together, our findings implicate that inhibition of ERK signaling pathway may have therapeutic potential for the treatment of allergic airway inflammation.     

An essential role for IL-18 in CD8 T cell-mediated suppression of IgE responses

The ability of CD8 T cells to suppress IgE responses is well established. Previously, we demonstrated that CD8 T cells inhibit IgE responses via the induction of IL-12, which promotes Th1 and suppresses Th2 responses. In this study, we show that IL-18 also plays an essential role in IgE suppression. In vitro, IL-18 synergized with IL-12 to promote Th1/T cytotoxic 1 and inhibit Th2/T cytotoxic 2 differentiation. OVA-specific TCR transgenic (OT-I) CD8 cells induced both IL-12 and IL-18 when cultured with OVA(257-264) peptide-pulsed dendritic cells. In vivo, IL-18(-/-) mice exhibited higher IgE and IgG1 levels compared with wild-type mice after immunization with OVA/alum. Furthermore, adoptive transfer of CD8 T cells from OVA-primed mice suppressed IgE responses in OVA/alum-immunized mice, but not in IL-18(-/-) mice. IgE suppression in IL-18(-/-) mice was restored if CD8 T cells were coadoptively transferred with IL-18-competent wild-type bone marrow dendritic cell progenitors, demonstrating an essential role of IL-18 in CD8 T cell-mediated suppression of IgE responses. The data suggest that CD8 T cells induce IL-18 production during a cognate interaction with APCs that synergizes with IL-12 to promote immune deviation away from the allergic phenotype. Our data identify IL-18 induction as a potentially useful target in immunotherapy of allergic disease.     

Binding the low affinity Fc epsilon R on B cells suppresses ongoing human IgE synthesis

Our results support the hypothesis that binding the low affinity Fc epsilon R (Fc epsilon R-II, CD23) on IgE-secreting B cells, directly suppresses IgE production. IgE production from AF-10/U266 (a human IgE plasmacytoma) decreased upon incubation with anti-IgE mAb or IgE:anti-IgE immune complexes (IgE-IC). Synthesis was suppressed a maximum of 51% with 10 micrograms/ml of IgE-IC after a 24-h incubation. Spontaneous in vitro IgE synthesis from the B cells of highly atopic individuals was also inhibited in a similar fashion. This effect was isotype specific as IgA or IgG immune complexes did not alter IgE production from AF-10 nor did IgE-IC affect IgA or IgG synthesis from lymphoblastoid cell lines making IgG (GM1500 and RPMI 8866) or IgA (GM1056). U266/AF-10 cells displayed both membrane IgE (greater than 90%) and Fc epsilon R-II (23%). To evaluate the role of these membrane proteins in the observed suppression of IgE synthesis, we treated U266/AF-10 cells with IgE-IC that bound Fc epsilon R-II but could not bind membrane IgE, as the mAb used was directed against an idiotypic determinant on the myeloma IgE (PS) used to make the IgE-IC. Suppression was maximal (greater than 50%) with these complexes at 0.1 micrograms/ml and at a 1/1 ratio of mAb anti-IgE to human myeloma IgE. When IgE-IC were used that were constructed with heat denatured IgE or F(ab')2 fragments of IgE, suppression was abrogated indicating IgE-Fc epsilon R binding was required. Neither PS IgE nor mAb 5.1 (the components of IgE-IC) alone affected IgE synthesis. Furthermore, a mAb binding directly to CD23 suppressed IgE synthesis from AF-10 up to 60%. Using limiting dilution analysis, we determined that IgE production per AF-10 cell was constant (0.9 pg/cell/24 h), independent of cell density and cells incubated with IgE-IC were uniformly suppressed. To clarify the mechanism of IgE-IC-induced suppression on AF-10 cells, we assessed both the proliferative rate and cell cycle distribution upon incubation with IgE-IC. There was no correlation between IgE production and [3H]TdR incorporation by AF-10 cells incubated with IgE-IC or anti-CD23 mAb. The distribution of cells within the cell cycle was unaffected by these treatments, with 60% of the cells in G1. These results define a direct role for the Fc epsilon R-II on B cells in the regulation of ongoing IgE synthesis.     

Blocking IL-15 prevents the induction of allergen-specific T cells and allergic inflammation in vivo

IL-15 has been shown to accelerate and boost allergic sensitization in mice. Using a murine model of allergic sensitization to OVA, we present evidence that blocking endogenous IL-15 during the sensitization phase using a soluble IL-15Ralpha (sIL-15Ralpha) suppresses the induction of Ag-specific, Th2-differentiated T cells. This significantly reduces the production of OVA-specific IgE and IgG and prevents the induction of a pulmonary inflammation. Release of proinflammatory TNF-alpha, IL-1beta, IL-6, and IL-12 as well as that of Th2 cytokines IL-4, IL-5, and IL-13 into the bronchi are significantly reduced, resulting in suppressed recruitment of eosinophils and lymphocytes after allergen challenge. It is of clinical relevance that the airway hyper-responsiveness, a major symptom of human asthma bronchiale, is significantly reduced by sIL-15Ralpha treatment. Ex vivo analysis of the draining lymph nodes revealed reduced numbers of CD8, but not CD4, memory cells and the inability of T cells of sIL-15Ralpha-treated mice to proliferate and to produce Th2 cytokines after in vitro OVA restimulation. This phenomenon is not mediated by enhanced numbers of CD4(+)/CD25(+) T cells. These results show that IL-15 is important for the induction of allergen-specific, Th2-differentiated T cells and induction of allergic inflammation in vivo.     

Calpeptin通过抑制GATA3减轻变应性鼻炎大鼠炎症

摘要 目的：本研究旨在评估钙蛋白酶抑制剂calpeptin减轻变应性鼻炎大鼠炎症的作用并探讨其机制。方法：将20只雄性SD大鼠采用数字表法随机分为4组：正常组（Normal）、变应性鼻炎组（AR）、地塞米松干预AR组（DXMS+AR）、calpeptin干预AR组（Calpeptin+AR）。造模成功后,对大鼠AR症状进行行为学评分,对大鼠鼻黏膜组织切片以HE和PAS染色法观察鼻黏膜病理改变;对大鼠外周血以ELISA法检测总IgE、IL-4、IL-13水平;对大鼠鼻黏膜组织以免疫蛋白印迹法检测GATA3蛋白表达水平。单因素方差分析进行多组间比较,LSD- t检验进行组间两两比较。结果：与Normal组相比,AR组大鼠的鼻部过敏症状、鼻黏膜嗜酸粒细胞计数及外周血总IgE水平均升高,Calpeptin与地塞米松均能减轻气道炎症,减少嗜酸性粒细胞浸润,降低血清中OVA诱导的IgE的生成。探讨机制发现,酶联免疫吸附试验检测Th2细胞因子,与Normal组比较,AR组血清IL-4、IL-13水平均升高（P＜0.05）,而Calpeptin与地塞米松均能降低血清IL-4、IL-13水平（P＜0.05）。免疫蛋白印迹法检测大鼠鼻黏膜GATA3蛋白表达水平显示,与Normal组比较,AR组鼻黏膜 GATA3表达升高（P＜0.05）,而Calpeptin与地塞米松组鼻黏膜 GATA3表达均下降（P＜0.05）。结论：腹腔注射calpeptin能够减轻变应性鼻炎大鼠局部和全身过敏反应,其机制可能下调GATA3表达,影响Th2细胞的分化及细胞因子的分泌有关。     

Influence of recombinant IL-4, IFN-alpha, and IFN-gamma on the production of human IgE-binding factor (soluble CD23)

This study documents the influence of rIL-4, IFN-gamma, and IFN-alpha on the production of IgE-BF and the expression of lymphocyte receptor for IgE or CD23 Ag (Fc epsilon R II) by human mononuclear cells. IL-4 increases the secretion of IgE-binding factor (BF) by highly purified B lymphocytes, adherent cells, and U937 monoblastic cells. The effect of IL-4 on purified B cells is augmented by costimulating the cells with F(ab')2 anti-IgM. IFN-gamma, IL-2, IL-1-alpha, or IL-1 beta and the low m.w. B cell growth factor have no effect on IgE-BF production by purified B cells even when they are used in combination with anti-IgM. Stimulation of purified T cells with IL-4 or IL-4 plus PMA leads to the production of very small amounts of IgE-BF that might well be derived from the contaminating non-T cells. IFN-gamma increases IgE-BF synthesis by unfractionated PBMC, T cell-depleted PBMC, adherent cells, and U937 cells suggesting that it induces monocytes to release IgE-BF, IFN-gamma suppresses the IL-4-induced Fc epsilon R II expression and IgE-BF production by highly purified B cells but not by PBMC or their T cell-depleted fractions. IFN-alpha inhibits IgE-BF production by IFN-gamma-stimulated PBMC and by IL-4-stimulated cells suggesting that it exerts its effect on B cells and on monocytes. Moreover IFN-alpha suppresses the IL-4-induced expression of Fc epsilon R II on B cells. Both IFN-alpha and IFN-gamma suppress the synthesis of IgE by PBMC in response to IL-4. Taken collectively the results indicate that: 1) IL-4 induces IgE-BF production by both B cells and monocytes, 2) IFN-gamma stimulates IgE-BF synthesis by monocytes but suppresses its production by IL-4-stimulated B cells, and finally 3) IFN-alpha inhibits IgE-BF synthesis in response to either IFN-gamma or IL-4.     

A helminth immunomodulator reduces allergic and inflammatory responses by induction of IL-10-producing macrophages

The coincidence between infections with parasitic worms and the reduced prevalence of allergic disease in humans and in animal models has prompted the search for helminth molecules with antiallergic and antiinflammatory potential. We report herein that filarial cystatin, a secreted protease inhibitor of filarial nematodes, suppresses Th2-related inflammation and the ensuing asthmatic disease in a murine model of OVA-induced allergic airway responsiveness. Treatment with recombinant filarial cystatin inhibited eosinophil recruitment, reduced levels of OVA-specific and total IgE, down-regulated IL-4 production, and suppressed allergic airway hyperreactivity when applied during or after sensitization and before challenge with the allergen. Depletion of macrophages by clodronate-containing liposomes prevented the curative effects and restored the levels of infiltrating cells, IgE, and allergic airway reactivity. Blocking of IL-10 by application of anti-IL-10 receptor Abs restored the reduced number of infiltrating cells and the levels of OVA-specific IgE. In contrast, depletion of regulatory T cells by anti-CD25 Abs had only limited effects. Cystatin also modulated macrophage-mediated inflammation in a murine model of dextran sulfate sodium-induced colitis, leading to reduction of inflammatory infiltrations and epithelial damage. Our data demonstrate that treatment with a single helminth protein can exert the antiallergic effects of helminth infections.     

Functional morphology of nuclear organizer regions of chromosomes and of nucleoli in cells of human multiple myeloma cell lines. II.Relationship between immunoglobulin E production and argentophilia of nuclear organizer regions of chromosomes in U 266 cell line

The IgE content in both cytoplasm and culture medium of U 266 myeloma cells, was studied by the enzyme-linked immunoassay in correlation with Ag-staining of NORs of chromosomes in their nuclei throughout 9 days after cell seeding. Proliferative activity of the cells was evaluated with 3H-thymidine labeling. The average values of both the cytoplasmic IgE content and its secretion level in U 266 cell population, being in logarithmic growth phase, were higher in S-phase cells as compared with G1-cells. On comparison of results of the present and previous (Turilova et al., 1998) studies it was revealed that U 266 myeloma cell line had a high stability of cell proliferation kinetics and IgE secretion and the dynamics of Ag-NORs-staining, while the number of argentophilic grains in the cell nuclei in the present experiment was higher to correlate with an enhanced IgE production. It is suggested that Ag-NORs-staining reflects the level of specific functional activity of cells in the U 266 line.     

Flt-3 ligand reverses late allergic response and airway hyper-responsiveness in a mouse model of allergic inflammation

Flt3 ligand (Flt3-L) is a growth factor for dendritic cells and induces type 1 T cell responses. We recently reported that Flt3-L prevented OVA-induced allergic airway inflammation and suppressed late allergic response and airway hyper-responsiveness (AHR). In the present study we examined whether Flt3-L reversed allergic airway inflammation in an established model of asthma. BALB/c mice were sensitized and challenged with OVA, and AHR to methacholine was established. Then mice with AHR were randomized and treated with PBS or 6 microg of Flt3-L i.p. for 10 days. Pulmonary functions and AHR to methacholine were examined after rechallenge with OVA. Treatment with Flt3-L of presensitized mice significantly suppressed (p < 0.001) the late allergic response, AHR, bronchoalveolar lavage fluid total cellularity, absolute eosinophil counts, and inflammation in the lung tissue. There was a significant decrease in proinflammatory cytokines (TNF-alpha, IL-4, and IL-5) in bronchoalveolar lavage fluid, with a significant increase in serum IL-12 and a decrease in serum IL-5 levels. There was no significant effect of Flt3-L treatment on serum IL-4 and serum total IgE levels. Sensitization with OVA significantly increased CD11b(+)CD11c(+) cells in the lung, and this phenomenon was not significantly affected by Flt3-L treatment. These data suggest that Flt3-L can reverse allergic airway inflammation and associated changes in pulmonary functions in murine asthma model.     

Inhibition of ongoing myeloma IgE synthesis in vitro by activated human T cells

The ability of activated T cells to suppress ongoing IgE synthesis in vitro was assessed using U266--a human myeloma cell line spontaneously producing IgE. T cells were able to inhibit U266 IgE synthesis in the presence of 10 micrograms/ml of Con A by 41.8% (p less than 0.01). T cells preincubated with 10 or 50 micrograms/ml of Con A and washed extensively were still able to inhibit U266 IgE synthesis in the absence of Con A by 41 and 46% (p less than 0.05 and p less than 0.02, respectively). The decrease in IgE measured was due to inhibition of newly formed IgE by U266, as shown by control experiments with cycloheximide. The inhibition was not due to the simple depletion of nutrient growth factors by the activated T cells, as it did not occur with MOLT-4, T cells that are very active metabolically; nor could it be reversed with medium containing IL 2 and B cell growth factors. Culture supernatants of Con A-activated T cells were also able to suppress IgE synthesis by U266 (21%; p less than 0.01), which suggests that upon appropriate activation, T cells secrete material(s) with inhibitory properties for IgE synthesis. Activation of T cells by mixed lymphocyte culture using puromycin-treated lymphoblastoid cell lines as stimulators also generated T cells that had suppressive activity for IgE synthesis. T cells activated with Con A and subsequently incubated with IgE demonstrated a diminished ability to suppress IgE synthesis. This observation is in agreement with the finding that patients with high levels of IgE may lack isotype-specific suppressor T cells for spontaneous IgE secretion. However, T cells from such patients have so far shown variable loss of IgE suppressive function. These results suggest that human IgE synthesis is susceptible to inhibition at a very differentiated stage, and this may be important in expression of allergic diseases.     

Essential role of macrophages in the initiation of allergic rhinitis in mice sensitized intranasally once with cedar pollen: regulation of class switching of immunoglobulin in B cells by controlling interleukin-4 production in T cells of submandibular lymph nodes

The production of allergen-specific IgE antibodies (Abs) in allergen-sensitized patients or animals has a mutual relationship with the immunologic response leading to allergic rhinitis. We recently reported that, after an intranasal injection of cedar pollen into mice, an interleukin-4 (IL-4)-dependent increase in serum nonspecific IgE Abs was a prerequisite for the production of serum allergen-specific IgE Abs. Here, we explored which lymphoid organs were responsive to the intranasally injected allergen and how IL-4 and IgE Abs were produced in the lymphocytes. Time-dependent changes in the total cell numbers and in in vitro IgE Ab production in various lymphoid organs revealed that the submandibular lymph nodes were the main responsible organ. After treatment with allergen (for IgE production) or allergen and complete Freund's adjuvant (for IgG production), we separated submandibular lymph node cells into macrophage-, lymphocyte-, and granulocyte-rich populations by discontinuous Percoll density-gradient centrifugation. Unexpectedly, bulk cells, but not the lymphocyte- or macrophage-rich populations, produced significant amounts of IL-4, IgE, and IgG; whereas production was restored by addition of Mac-1(+) cells from the macrophage-rich to the lymphocyte-rich fraction. Furthermore, a combination of the lymphocyte-rich population (for IgG [or IgE]) production) and the macrophage-rich population (for IgE [or IgG]) production) produced a large amount of IgE (or IgG). These results indicate that, in the initiation of allergic rhinitis, macrophages in the submandibular lymph nodes are essential not only for IL-4 or immunoglobulin production, but also for class switching of immunoglobulin in lymphocytes.     

Oral administration of chitin down-regulates serum IgE levels and lung eosinophilia in the allergic mouse

Previous studies showed that local macrophages phagocytose nonantigenic chitin particles (1-10 micrometer polymers of N-acetyl-d -glucosamine) through mannose receptors and produce IL-12, IL-18, and TNF-alpha. These cytokines lead to the production of IFN-gamma by NK cells. To determine whether chitin could down-regulate Th2 responses, chitin was given orally (8 mg/day for 3 days before and 13 days during ragweed allergen immunization) in BALB/c and C57BL/6 mice. These ragweed-immunized mice were given ragweed intratracheally on day 11. Three days after the challenge, the immunized mice with saline (controls) showed increases in serum IgE levels and lung eosinophil numbers. The chitin treatment resulted in decreases of these events in both strains. To dissect the inhibitory mechanisms of Th2 responses, spleen cells (4 x 106 cells/ml) isolated from the ragweed-immunized mice (controls) were cultured in the presence of ragweed and/or chitin for 3 days (recall responses). Ragweed alone stimulated the production of IL-4 (0.6 ng/ml), IL-5 (20 U/ml), and IL-10 (3.2 ng/ml), but not IFN-gamma. Ragweed/chitin stimulation resulted in significant decreases of IL-4, IL-5, and IL-10 levels and the production of IFN-gamma (48 U/ml). Moreover, spleen cells isolated from the chitin-treated mice showed ragweed-stimulated IFN-gamma production (15 U/ml) and significantly lower levels of the Th2 cytokines, suggesting that the immune responses were redirected toward a Th1 response. Collectively, these results indicate that chitin-induced innate immune responses down-regulate Th2-facilitated IgE production and lung eosinophilia in the allergic mouse.     

TSLP receptor is not essential for house dust mite-induced allergic rhinitis in mice

TSLP induces Th2 cytokine production by Th2 cells and various other types of cells, thereby contributing to Th2-type immune responses and development of allergic disorders. We found that house dust mite (HDM) extract induced TSLP production by nasal epithelial cells, suggesting that TSLP may be involved in development of HDM-induced allergic rhinitis (AR). To investigate that possibility in greater detail, wild-type and TSLP receptor-deficient (TSLPR^?/?) mice on the C57BL/6J background were repeatedly treated intranasally with HDM extract. The frequency of sneezing, numbers of eosinophils and goblet cells, thickness of submucosal layers, serum levels of total IgE and HDM-specific IgG1, and levels of IL-4, IL-5 and IL-13 in the culture supernatants of HDM-stimulated LN cells were comparable in the two mouse strains. Those findings indicate that, in mice, TSLPR is not crucial for development of HDM-induced AR.     

Oral Administration of a Hop Water Extract Ameliorates the Development of Dermatitis Induced by the Periodical Topical Application of a Mite Antigen in Atopic Dermatitis Model NC/Nga Mice

We investigated the inhibitory effect of an oral administration of a hop water extract (HWE) on the development of dermatitis by using NC/Nga atopic dermatitis model mice. The induction of allergic dermatitis was conducted by tape-stripping and topical application of a mite antigen (Dermatophagoides farinae) on to the ear once a week for 10 weeks. HWE was orally administered at a dose of 100 or 500 mg/kg. The total immunoglobulin E (IgE) concentration in serum and the ear thickness were periodically examined. Finally, the antigen-specific IgE level in the serum and the production of interleukin (IL)-4, IL-12 and interferon (IFN)-γ from splenocytes and cervical lymph node cells were measured. The oral administration of HWE significantly inhibited the increase of total IgE production and ear swelling throughout the experimental period. The production of IL-12 was significantly lower in the HWE administered group than in the control group. The results suggest that the intake of HWE may be effective in preventing and alleviating the development of atopic dermatitis-like skin disease.     

Th2 cytokine production from mast cells is directly induced by lipopolysaccharide and distinctly regulated by c-Jun N-terminal kinase and p38 pathways

Mast cells secrete multiple cytokines and play an important role in allergic inflammation. Although it is widely accepted that bacteria infection occasionally worsens allergic airway inflammation, the mechanism has not been defined. In this study, we show that LPS induced Th2-associated cytokine production such as IL-5, IL-10, and IL-13 from mast cells and also synergistically enhanced production of these cytokines induced by IgE cross-linking. LPS-mediated Th2-type cytokine production was abolished in mouse bone marrow-derived mast cells derived from C3H/HeJ mice, suggesting that Toll-like receptor 4 is essential for the cytokine production. Furthermore, we found that mitogen-activated protein kinases including extracellular signal-regulated kinase 1/2, c-Jun N-terminal kinase, and p38 kinase were activated by LPS stimulation in bone marrow-derived mast cells. Inhibition of extracellular signal-regulated kinase activation has little effect on LPS-mediated cytokine production. In contrast, inhibition of c-Jun N-terminal kinase activation significantly suppressed both IL-10 and IL-13 expression at both mRNA and protein levels. Interestingly, although inhibition of p38 did not down-regulate the mRNA induction, it moderately decreased all three cytokine productions by LPS. These results indicate that LPS-mediated production of IL-5, IL-10, and IL-13 was distinctly regulated by mitogen-activated protein kinases. Our findings may indicate a clue to understanding the mechanisms of how bacteria infection worsens the clinical features of asthma.