Effects of suplatast tosilate, a new type of anti-allergic agent, on airway cough hypersensitivity induced by airway allergy in guinea-pigs

BACKGROUND: Cough receptor hypersensitivity is a fundamental feature of some conditions presenting with chronic non-productive cough. Suplatast tosilate, an anti-allergic agent, is a T helper (Th)2 cytokine inhibitor that inhibits the synthesis of interleukin (IL)-4, IL-5, immunoglobulin (Ig)E production, and local eosinophil accumulation. OBJECTIVE: The purpose of this study was to investigate the effect of suplatast on antigen-induced airway cough hypersensitivity and eosinophil infiltration into the airway. METHODS: Number of coughs elicited by inhalation of increasing concentrations of capsaicin (10-8, 10-6 and 10-4 M) was counted 24 h after an antigen challenge in conscious guinea-pigs and then bronchoalveolar lavage was performed. We investigated the effect of single (before antigen challenge or capsaicin provocation) or repetitive treatment with intraperitoneal suplatast at a dose of 10 or 30 mg/kg on antigen-induced cough hypersensitivity. RESULTS: Twenty-four hours after antigen challenge, guinea-pigs developed an increase in cough receptor sensitivity to inhaled capsaicin and eosinophil infiltration in the airways. After a 2-week treatment with suplatast, but not after only a single treatment before antigen challenge or capsaicin provocation, the antigen-induced early phase bronchoconstriction, cough hypersensitivity, and airway eosinophilia were inhibited in a dose-dependent manner. CONCLUSION: These results indicate that suplatast inhibits airway cough hypersensitivity underlying allergic eosinophilic inflammation.     

Suplatast tosilate inhibits goblet-cell metaplasia of airway epithelium in sensitized mice

BACKGROUND: IL-4 and IL-13 play a putative role in mucus hypersecretion in asthma. Suplatast tosilate prevents the synthesis of T(H2) cytokines. OBJECTIVE: Because suplatast tosilate inhibits T(H2) cytokines but does not inhibits IFN-gamma production, we examined the effect of suplatast on IL-4- or IL-13- and ovalbumin (OVA)-induced mucin synthesis in NCI-H292 cells in vitro and in bronchi of pathogen-free BALB/c mice in vivo. METHODS: In vitro, NCI-H292 cells were preincubated with suplatast tosilate (0.1-100 microgram/mL) 1 hour before adding human recombinant IL-4 (10 ng/mL). In vivo, mouse recombinant IL-4 or IL-13 (250 ng per/mouse) was instilled intranasally in mice pretreated with suplatast tosilate (50 mg.kg(-1).d(-1)). Mucous glycoconjugates were stained with Alcian blue (AB)/periodic acid-Schiff (PAS) stain. To evaluate effects of suplatast tosilate on goblet-cell metaplasia in OVA-sensitized mice, animals were pretreated with suplatast tosilate (1-50 mg.kg(-1).d(-1)) intragastrically. IL-4 and IL-13 were measured, and allergic inflammatory cells were analyzed in bronchoalveolar lavage fluid of OVA-sensitized mice. RESULTS: Pretreatment with suplastast did not prevent IL-4- or IL-13-induced increase in mucous glycoconjugate production in NCI-H292 cells or in mice. OVA sensitization increased AB/PAS-stained area of the epithelium (48.1% +/- 2.4%, P <.01 compared with control mice). Suplatast tosilate inhibited OVA-induced goblet-cell metaplasia in airway epithelium in a dose-dependent fashion; 50 mg.kg(-1).d(-1) decreased the AB/PAS area to 22.7% +/- 2.7% (P <.05 compared with OVA sensitization alone). Pretreatment with suplatast tosilate also prevented OVA-induced increase in IL-4 and IL-13 levels and decreased the number of lymphocytes and eosinophils in bronchoalveolar lavage fluid (P <.05 compared with values of mice given OVA alone). CONCLUSION: These results indicate that suplatast tosilate prevents allergen-induced goblet-cell metaplasia and the recruitment of eosinophils and lymphocytes into the airways. These results suggest that this effect is due to the prevention of the production of T(H2) cytokines in airways.     

Inhibitory effect of suplatast tosilate on eosinophil migration]

Suplatast tosilate has been shown to inhibit generation of Th2-type cytokines in vitro and used in the treatment of allergic diseases. Although the exact mechanism remains unknown, this compound attenuates the eosinophil infiltration in the asthmatic airway. In the present study, we examined whether suplatast tosilate directly modulates eosinophil migration in response to inflammatory mediators in vitro. Suplatast did not modify the spontaneous migration of eosinophils. On the other hand, eosinophil migration in response to PAF (1 microM) was significantly inhibited by 1 microM suplatast. Similarly, IL-5 (100 pM)-induced eosinophil migration was inhibited by 1 microM suplatast. These results suggest that suplatast tosilate inhibits eosinophil locomotion in response to PAF or IL-5 and thereby attenuates infiltration of the cells in allergic inflammation.     

Selective enhancement of production of IgE, IgG4, and Th2-cell cytokine during the rebound phenomenon in atopic dermatitis and prevention by suplatast tosilate.

BACKGROUND: Atopic dermatitis is a chronic inflammatory skin disease, which is commonly treated with topical steroids. It is, however, associated with rebound after therapy has been discontinued. OBJECTIVE: This study was designed to elucidate the mechanisms of the rebound phenomenon, and to test the effect of an oral anti-allergic medication, suplatast tosilate, on atopic dermatitis. METHODS: This is a randomized, placebo controlled study. Patients with atopic dermatitis who had been treated with strong steroid ointment (dexamethasone valerate) for several years were divided into two groups. One group (the control group, n = 15) was treated with a non-steroid anti-inflammatory ointment (bufexamac ointment), while the other group (the suplatast tosilate group, n = 17) was treated with the anti-allergic medications, suplatast tosilate and bufexamac ointment. In each group, in vitro production of immunoglobulins and cytokines before and after 2 weeks of treatment was measured. RESULTS: In the control group, 15 of the 15 patients experienced rebound and mean production of IgE, IgG4, IL-4, IL-5, IL-10, and IL-13 was enhanced after 2 weeks. In contrast, only 2 of the 17 patients in the suplatast tosilate group experienced rebound. There was no enhancement of production of immunoglobulins and cytokines after 2 weeks of treatment. CONCLUSION: Enhanced production of the Th2-cell cytokines, which selectively induces IgE and IgG4 production, may be involved in the pathogenesis of the rebound phenomenon, and that suplatast tosilate may prevent the rebound phenomenon by down-regulating the production of these cytokines.     

Effect of suplatast tosilate on goblet cell metaplasia in patients with asthma

BACKGROUND: Goblet cell metaplasia is a pathologic characteristic of asthma, associated with excess mucus secretion. Interleukin (IL)-4 and IL-13 plays an important role in mucus hypersecretion. Suplatast tosilate (suplatast), an antiallergic agent, is a Th2 cytokine inhibitor that suppresses the synthesis of IL-4, IL-5, IL-13, and eosinophilic airway inflammation. OBJECTIVE: We examined the effects of suplatast on mucus production in bronchial biopsy specimens taken from asthmatic subjects. METHODS: Oral suplatast 300 mg daily, or placebo was administered for 3 months in a double-blind, parallel-group study in 25 patients with asthma. Biopsy specimens were evaluated at before and after treatment for alcian blue/period acid-Schiff (AB/PAS), MUC5AC staining in bronchial epithelium and IL-4+, IL-13+ cells as well as inflammatory cells in lamina propria. RESULTS: There were significant decreases in the percentage of AB/PAS (P < 0.01) and MUC5AC (P < 0.01) stained area in the suplatast group. These changes were accompanied by significant decreases in IL-4+ and IL-13+ cells in suplatast-treated subjects. Additionally, we have observed that the number of infiltrating eosinophils and CD4+ T cells significantly decreased. CONCLUSIONS: These findings suggest that suplatast prevents goblet cell metaplasia through modulation of Th2 cytokine production and the recruitment of eosinophils and CD4+ T cells in the asthmatic airways.     

Suplatast tosilate inhibits eosinophil production and recruitment into the skin in murine contact sensitivity

Antiallergic drugs and antihistamines have been widely used for controlling mucosal allergic diseases in which eosinophilia is prominent. Although H1-receptor antagonists are effective for treating histamine-induced wheal and itch in urticaria, the effects of antihistamines and antiallergic agents on other eosinophilic skin diseases remain to be determined. We investigated the effects of oral administration of antiallergic drugs and antihistamines, such as suplatast tosilate, emedastine difumarate, and azelastine hydrochloride, on a novel murine model of eosinophilia in contact sensitivity to picryl chloride. Among the drugs tested, only suplatast tosilate remarkably inhibited blood and tissue eosinophilia and the ear swelling responses. The inhibitory effects on eosinophilia seemed to be mediated by the suppression of IL-5 production in spleen cells during eosinophil development, while the effects on the ear swelling response seemed to be mediated by suppression of IL-4 production in immune lymph node cells in the efferent phase. Suplatast tosilate may effectively treat eosinophilic skin diseases in which Th2-cell-derived cytokines are predominant.     

Inhibitory effects of suplatast tosilate on the differentiation and function of monocyte-derived dendritic cells from patients with asthma

Background Dendritic cells (DCs) are antigen‐presenting cells that efficiently activate T cells. Objective We examined the effects of suplatast tosilate, which prevents T‐helper type 2 responses, on the differentiation and function of monocyte‐derived DCs (moDCs). Methods DCs were differentiated in vitro from peripheral monocytes from patients with asthma by the addition of granulocyte macrophage colony‐stimulating factor and IL‐4 in the presence or absence of suplatast tosilate. Cell surface molecules (CD1a, CD14, CD80, CD83, CD86, HLA‐DR) on immature and mature DCs were analysed with flow cytometry, and the secretion of CC chemokine ligand (CCL)17 (thymus and activation‐regulated chemokine), IL‐12p70, IL‐12p40, and IL‐10 was measured with an ELISA. We also studied the proliferative responses of allogeneic CD4⁺ T cells from healthy subjects to DCs differentiated in the presence of suplatast tosilate. In addition, the production of IFN‐γ and IL‐5 by CD4⁺ T cells after coculture with untreated DCs or suplatast tosilate‐treated DCs was measured with ELISA. Results Suplatast tosilate significantly inhibited the expression of CD1a, CD80, and CD86 on immature DCs and of CD1a, CD80, CD83, and CD86 on mature DCs. Suplatast tosilate also significantly inhibited the secretion of CCL17, IL‐12p70, and IL‐12p40; however, the secretion of IL‐10 was not affected. The proliferative responses of allogeneic CD4⁺ T cells to suplatast tosilate‐treated DCs were suppressed. Moreover, suplatast tosilate‐treated DCs had an impaired capacity to stimulate CD4⁺ T cells to produce IFN‐γ and IL‐5. Conclusion Suplatast tosilate inhibits the differentiation, maturation, and function of moDCs.     

An annexin 1 (ANXA1)-derived peptide inhibits prototype antigen-driven human T cell Th1 and Th2 responses in vitro

BACKGROUND: Annexin-1 (ANXA1, lipocortin 1) is a pleiotrophic protein produced by many cell types including peripheral blood leucocytes. Although it has been shown to inhibit "macroscopic" inflammatory processes in animal models, its direct effects on antigen-activated human T cells have not been studied. OBJECTIVE: To test the hypothesis that ANXA1-derived peptides inhibit antigen-driven prototype Th1 and Th2-type human T cell responses of clinical relevance and lectin-driven responses in vitro. METHODS: Peripheral blood mononuclear cells (PBMC) were isolated from 14 atopic subjects sensitized to house dust mite allergen (Dermatophagoides pteronyssinus, Der p) and purified protein derivative (PPD) of Mycobacterium tuberculosis. PBMC (1 x 106/mL) were cultured with phytohaemagglutinin (PHA; 5 microg/mL; 4 days), Der p (25 microg/mL; 6 days), PPD (10 microg/mL, 6 days) or medium control. Two ANXA1-derived peptides, Ac2-26 and AF-2 (5-500 microM), were assessed for possible inhibition of PHA-and antigen-induced T cell proliferation (measured by 3H-thymidine uptake), while Ac2-26 was assessed for inhibition of Der p-induced interleukin (IL)-5 release and PPD-induced interferon-gamma (IFN-gamma) release (measured by ELISA). Comparison was made with dexamethasone as an established inhibitory control. Endogenous production by PBMC of cell surface-associated and intracellular ANXA1 in response to PHA, Der p and PPD in the presence and absence of dexamethasone was measured by specific ELISA. RESULTS: Both PHA- and antigen-induced T cellular proliferation were inhibited by dexamethasone. Although neither ANXA1-derived peptide significantly altered PHA-induced proliferation, both effected concentration-dependent reductions in antigen-induced proliferation, Ac2-26 being the more potent. Peptides of identical amino acid composition to Ac2-26 and AF-2, but of random sequence, were ineffective at equivalent concentrations. In addition, Ac2-26 and dexamethasone inhibited Der p-induced IL-5 release and PPD-induced IFN-gamma release in a concentration-dependent fashion. Endogenous ANXA1 was detectable in PBMC, but at concentrations approximately 104-fold lower, in molar terms, than the effective concentrations of the exogenously added, ANXA1-derived inhibitory peptides. Endogenous production was not significantly altered by any of the T cell stimuli employed in this study, in the presence or absence of dexamethasone. CONCLUSION: In prototype Th1 and Th2-type human T cell responses, ANXA1-derived peptides can inhibit antigen-driven cellular proliferation and cytokine production.     

CD28 and secretory immunoglobulin A-dependent activation of eosinophils: inhibition of mediator release by the anti-allergic drug, suplatast tosilate

BACKGROUND: Eosinophils are major effector cells in allergic diseases. After their recruitment to sites of inflammation, they contribute to the pathophysiology of the disease by releasing granule proteins and cytokines. Suplatast tosilate (IPD-1151T), a new anti-allergic agent, has shown beneficial effect in the treatment of asthma, associated with reduced bronchoalveolar lavage eosinophil infiltration and eosinophilic cationic protein (ECP) release in serum and sputum. OBJECTIVE: We investigated whether suplatast tosilate could exert direct effects on human eosinophil activation. METHODS: Eosinophils from hypereosinophilic patients or normal donors were purified by Percoll gradient and the magnetic cell separation system. Chemotaxis was studied using the Boyden chamber technique using three chemoattractants, formyl-methionine-leucine-phenylalanine (fMLP), IL-5 and eotaxin. Oxidative metabolism was determined by a luminol-dependent chemiluminescence assay after activation with eotaxin or secretory IgA (sIgA). The release of ECP and eosinophil derived neurotoxin (EDN) was measured by radioimmunoassay and cytokine production was determined by ELISA following activation with sIgA or anti-CD28. RESULTS: The chemotactic response to fMLP, IL-5 and eotaxin was significantly inhibited by IPD-1151T. Suplatast tosilate was partially inhibiting the release of reactive oxygen species (ROS) induced by eotaxin and sIgA. Activation by sIgA and CD28 ligation resulted in the release of ECP and EDN, which was inhibited by IPD-1151T. Upon activation by anti-CD28, only IL-13 production was inhibited by IPD-1151T, whereas release of IL-2 and IFN-gamma was not affected. IL-10 release induced by sIgA was also inhibited by IPD-1151T. Additionally, the pro-inflammatory cytokine IL-6, which was secreted following anti-CD28 and sIgA stimulation, was strongly inhibited by IPD-1151T. CONCLUSION: Through inhibition of chemotaxis, IPD-1151T might limit the number of eosinophils at the inflammation site. Furthermore, it could reduce the pathological potential of eosinophils by inhibiting the release of ROS and cationic proteins, main inflammatory mediators produced by eosinophils. Moreover, the inhibition of immunoregulatory cytokines released by eosinophils could locally modify the immune response.     

Effects of suplatast tosilate on allergic eosinophilic airway inflammation in patients with mild asthma

BACKGROUND: Bronchial asthma is a chronic inflammatory disease characterized mainly by infiltration of the airway mucosa by various inflammatory cells, notably eosinophils. T(H)2-type cytokines are suggested to be deeply involved in the pathogenesis of asthma. OBJECTIVE: We sought to determine the suppressive effects of suplatast tosilate, an inhibitor of T(H)2-type cytokines, on eosinophilic inflammation of the bronchial mucosa in patients with mild asthma. METHODS: Airway hyperresponsiveness tests, pulmonary function tests, eosinophil measurements in induced sputum, and bronchial mucosa biopsies were performed before and after treatment with suplatast tosilate for 6 weeks in 15 patients with mild asthma and in 13 control patients with mild asthma not receiving suplatast tosilate. This study was performed as a case-controlled open study. RESULTS: In the treatment group a significant improvement in the provocation concentration of histamine was observed (P <.05). Improvements in peak expiratory flow (P <.01) and in symptom score (P <.05) were also noted in the suplatast tosilate-treated group. Moreover, the average number of infiltrating eosinophils and EG2(+) cells significantly decreased (both P <.05), as did the ratios of eosinophils and EG2(+) cells in sputum (both P <.01). The average number of CD4(+) and CD25(+) T lymphocytes also decreased (both P <.05). CONCLUSION: Suplatast tosilate appears to inhibit allergic airway inflammation mediated by T(H)2-type cytokine and to improve clinical symptoms in patients with mild asthma.     

A possible role of TARC in antigen-specific Th2-dominant responses in patients with Paragonimiasis westermani

BACKGROUND: Paragonimiasis westermani (Pw), a common parasitic zoonosis in Asia, is typically associated with eosinophilia. Th2 cytokines seem to have an important role in the clinical manifestations of this disease. Thymus and activation-regulated chemokine (TARC) is a potential key regulator of Th2-mediated inflammation. The purpose of the present study was to evaluate the antigen-specific Th2-dominant responses in patients with Pw. METHODS: The concentrations of cytokines and chemokines in supernatants of peripheral blood mononuclear cell (PBMC) cultures with or without antigen stimulation were measured by enzyme-linked immunosorbent assay (ELISA). TARC levels in serum from Pw patients were also evaluated by ELISA. The number of Th2 cells expressing the CC-chemokine receptor 4 (CCR4) in the peripheral blood was evaluated by flow cytometry. RESULTS: Antigen-stimulation induced production of IL-5 and IL-13, but not IFN-gamma from PBMC cultures in patients with Pw. Pw patients had elevated serum TARC levels and a higher proportion of CCR4-expressing cells among CD4+ T cells in the peripheral blood. There were also higher levels of TARC, but not IP-10, in supernatants of antigen-stimulated PBMC culture compared to unstimulated PBMC culture in patients with Pw. CONCLUSION: Our findings clarify antigen-specific Th2-dominant responses in patients with Pw and suggest a possible role for TARC in Th2-dominant responses.     

IL-10 induces a Th2 cell tolerance in allergic asthma

BACKGROUND: Interleukin (IL)-10 induces a long-term antigen-specific anergy in human CD4+ T cells. METHODS: Peripheral blood mononuclear cells (PBMCs) were isolated from house dust mite (Dermatophagoides farinae, Der f)-sensitized asthmatic patients. PBMCs were stimulated with Der f antigen for 72 h immediately after purification or after 48 h of resting culture with medium, and IL-10 and IL-5 in the culture supernatant were measured. PBMCs were also stimulated with Der f antigen for 7 days either immediately after purification or after 48 h of resting culture, after which cells were collected. Secondary proliferative responses of these cells to stimulation for 3 days with Der f antigen and mitomycin C-treated PBMCs as antigen-presenting cells or with phorbol myristate acetate (PMA) plus calcium ionophore were investigated. RESULTS: Stimulation of PBMCs with Der f antigen immediately after purification significantly increased the proliferative response and IL-5 production. Stimulation of PBMCs with Der f antigen after resting culture with medium alone for 48 h significantly decreased IL-5 production and markedly increased IL-10 production. Although activation of cells with Der f antigen immediately after purification significantly increased secondary proliferative responses, stimulation after 48 h of resting culture failed to increase secondary proliferative responses. However, proliferation recovered when cells were activated with PMA plus calcium ionophore. CONCLUSION: These results suggest that antigen-specific Th2 cells are anergized by IL-10 and that Th2 cell tolerance may suppress eosinophilic inflammation in allergic asthma.     

Immune mechanisms in congenital cytomegalovirus infection: activation of CMV-specific T helper cells (CMV-Th) by exogenous IL-2.

Infants with congenital CMV infection have a specific defect in CMV-induced lymphocyte proliferation, providing a model for investigation of mechanisms of viral immune recognition and immune response. In the present study the possible role of a defect in lymphokine activation of CMV-specific T helper cells (Th) was examined. IL-1 activity was detected in supernatants of patient mononuclear cell (MNC) cultures stimulated with CMV. In contrast, no IL-2 activity could be detected in supernatants of CMV-stimulated MNC cultures, whereas PHA induced normal IL-2 production. Addition of low concentrations of either crude TCGF or recombinant IL-2 (rIL-2) resulted in 2-4 fold augmentation of CMV-specific lymphocyte proliferation; exogenous IL-2 had no effect on MNC responses to HSV. CMV-specific Th lines/clones were established from three congenital CMV patients by initial stimulation of MNCs with CMV antigen and 0.1 U/ml rIL-2, followed by repeated stimulation with CMV, HLA-matched allogeneic feeder cells and 10% TCGF. The resulting CMV Th lines/clones proliferated specifically in response to stimulation with CMV antigen and produced endogenous IL-2. Thus, the immune deficiency associated with congenital CMV may either be due to an intrinsic defect in CMV-Th activation or CMV-specific suppressor cell activity.     

Theophylline suppresses IL-5 and IL-13 production,and lymphocyte proliferation upon stimulation with house dust mite in asthmatic children

BACKGROUND: Although theophylline has long been used as a medication for bronchial asthma (BA), much remains to be elucidated about its action on Th2 cells, which play a critical role in the development of BA. OBJECTIVE: This study aimed to clarify the effect of theophylline on Th2 cells in an allergen-specific manner in children with BA. METHODS: Peripheral blood mononuclear cells (PBMCs) from 32 children with BA were stimulated with house dust mite (HDM) or a purified HDM allergen Der f 1 in the presence or absence of theophylline at a therapeutic concentration (5-20 microg/ml). The proliferation of lymphocytes and the secretion of IL-5 and IL-13 were measured to estimate the influence of theophylline. RESULTS: Theophylline at a concentration of 20 microg/ml significantly suppressed lymphocyte proliferation induced by 6-day culture with HDM or Der f 1. It also significantly reduced the production of IL-5 and IL-13 upon stimulation with HDM or Der f 1. Suppression of cytokine production and lymphocyte proliferation increased with concentrations of theopylline between 5 and 20 microg/ml. CONCLUSION: Theophylline suppresses the proliferation of lymphocytes and the production of proinflammatory Th2 cytokines, IL-5 and IL-13 induced by stimulation of PBMCs with HDM in children with BA.     

Inhibitory effects of fluvastatin on cytokine and chemokine production by peripheral blood mononuclear cells in patients with allergic asthma

BACKGROUND: Statins have anti-inflammatory effects on immune cells. OBJECTIVE: To investigate the immunomodulatory effects of fluvastatin on peripheral blood mononuclear cells (PBMCs) after allergen-specific and non-allergen-specific stimulation in patients with asthma and in healthy subjects. METHODS: PBMCs from seven patients with asthma who showed elevated immunoglobulin (Ig)E to house dust mite were isolated and stimulated with Dermatofagoides farinae, purified protein derivative, and phytohaemagglutinin (PHA) in the presence or absence of fluvastatin. PBMCs from seven healthy subjects were stimulated with PHA. The effects of fluvastatin on cell proliferation and production of cytokines (interferon [IFN]-gamma and interleukin [IL]-5) and chemokines (chemokine CXC motif, ligand [CXCL10], and CC chemokine ligand [CCL17]) were measured. Migration of T helper (Th)1 and Th2 cell lines was also investigated. The expression of CXCR3 and CCR4 was analysed with flow cytometry. Steroid-insensitive PBMCs induced by preculture with IL-2 and IL-4 were also evaluated. Some experiments were performed in the presence of mevalonic acid. RESULTS: Fluvastatin inhibited the proliferation of PBMCs and decreased the production of IL-5, IFN-gamma, CCL17, and CXCL10 after allergen-specific and non-allergen-specific stimulation; all these effects, except for decreased CXCL10 production, were partially reversed by mevalonic acid. Culture supernatants obtained in the presence of fluvastatin prevented the migration of Th1 and Th2 cell lines in a dose-dependent manner. In addition, CCR4 and CXCR3 expression on CD4(+) T cells was not affected by the presence of fluvastatin. Fluvastatin inhibited the proliferative response of steroid-insensitive PBMCs to phytohaemagglutinin. CONCLUSION: Fluvastatin has inhibitory effects on cytokine and chemokine production, and thus might be used as a potential therapeutic agent in severe asthma.     

Alginic acid oligosaccharide suppresses Th2 development and IgE production by inducing IL-12 production

BACKGROUND: Since allergen-specific IgE is directly involved in the type I allergic reaction, development of a method for inhibiting Th2 responses which lead to the induction of IgE production would be a useful approach for preventing allergic disorders. The ability and mechanism of alginic acid oligosaccharide (ALGO), an oligosaccharide obtained from natural edible polysaccharide, for suppressing Th2 responses was examined in detail. METHODS: Lymph node cells obtained from beta-lactoglobulin (beta-LG)-primed BALB/c mice were cultured in vitro with an antigen for 3 days in the absence or presence of ALGO. The amount of cytokine in each culture supernatant was measured. The effect of ALGO on Th2 development was also examined by using ovalbumin specific T cell receptor transgenic mice. Antibody production in the serum of BALB/c mice that had been immunized with beta-LG or beta-LG plus ALGO was investigated. RESULTS: The production of IFN-gamma induced by antigen stimulation was upregulated by ALGO in a dose-dependent manner. IL-12 production was also enhanced by ALGO, and the addition of the anti-IL-12 antibody to the culture abrogated the effect of ALGO. On the other hand, IL-4 production by antigen-stimulated splenocytes of transgenic mice was suppressed in the presence of ALGO. Furthermore, IgE production by ALGO-treated mice was significantly inhibited compared with control mice. CONCLUSIONS: These results indicate that ALGO suppressed antigen-induced Th2 development by inducing IL-12 production. ALGO also inhibited in vivo IgE production. These findings suggest that ALGO is expected to be an edible anti-allergic agent.     

Selective recruitment of CCR4-bearing Th2 cells toward antigen-presenting cells by the CC chemokines thymus and activation-regulated chemokine and macrophage-derived chemokine

Helper T cells are classified into Th1 and Th2 subsets based on their profiles of cytokine production. Th1 cells are involved in cell-mediated immunity, whereas Th2 cells induce humoral responses. Selective recruitment of these two subsets depends on specific adhesion molecules and specific chemoattractants. Here, we demonstrate that the T cell-directed CC chemokine thymus and activation-regulated chemokine (TARC) was abundantly produced by monocytes treated with granulocyte macrophage colony stimulating factor (GM-CSF) or IL-3, especially in the presence of IL-4 and by dendritic cells derived from monocytes cultured with GM-CSF + IL-4. The receptor for TARC and another macrophage/dendritic cell-derived CC chemokine macrophage-derived chemokine (MDC) is CCR4, a G protein-coupled receptor. CCR4 was found to be expressed on approximately 20% of adult peripheral blood effector/memory CD4+ T cells. T cells attracted by TARC and MDC generated cell lines predominantly producing Th2-type cytokines, IL-4 and IL-5. Fractionated CCR4+ cells but not CCR4- cells also selectively gave rise to Th2-type cell lines. When naive CD4+ T cells from adult peripheral blood were polarized in vitro, Th2-type cells selectively expressed CCR4 and vigorously migrated toward TARC and MDC. Taken together, CCR4 is selectively expressed on Th2-type T cells and antigen-presenting cells may recruit Th2 cells expressing CCR4 by producing TARC and MDC in Th2-dominant conditions.     

IL-16 inhibits IL-5 production by antigen-stimulated T cells in atopic subjects

BACKGROUND: We have previously shown increased expression of the CD4+ cell chemoattractant IL-16 at sites of airway allergic inflammation. Little is known about the significance of IL-16 in allergic inflammation and its role in allergen-driven T-cell cytokine responses. Because IL-16 interacts specifically with CD4+ T cells, we hypothesized that IL-16 released at sites of inflammation may modulate the pattern of cytokines produced by CD4+ T cells. OBJECTIVE: We investigated the effects of exogenous rhIL-16 on cytokine production of PBMCs from atopic and nonatopic subjects in response to antigen and PHA. METHODS: Primary cultures of freshly isolated PBMCs from ragweed-sensitive atopic subjects and nonatopic subjects were stimulated with ragweed or PHA in the presence or absence of rhIL-16. Supernatant levels of IL-4, IL-5, and IFN-gamma were determined by means of ELISA at different time points between 2 and 6 days. Effects of IL-16 on antigen-induced cellular proliferative responses were determined. RESULTS: No IL-4 protein was detected after antigen stimulation of PBMCs from atopic subjects, whereas significant levels of IL-5 were measured on day 6 (median, 534.9 pg/mL). IL-5 secretion was abolished in PBMC cultures depleted of CD4+ cells. The addition of rhIL-16 in antigen-stimulated PBMC cultures significantly reduced the amount of IL-5 released (median, 99.8 pg/mL; P <.001). Detectable levels of IFN-gamma (median, 53.3 pg/mL) were identified after antigen stimulation. The addition of rhIL-16 in antigen-stimulated PBMC cultures significantly increased IFN-gamma levels (median, 255.6 pg/mL; P <.05). Effects of rhIL-16 appear to be specific for antigen-stimulated PBMCs in atopic subjects because rhIL-16 did not alter IL-5 or IFN-gamma production in response to PHA nor did rhIL-16 alter cytokine production in nonatopic normal subjects. CONCLUSION: These studies suggest that IL-16 can play a role in regulating the production of cytokines seen in allergic states in response to antigen.     

Der p, IL-4, and TGF-beta cooperatively induce EGFR-dependent TARC expression in airway epithelium

Thymus and Activation-Regulated Chemokine (TARC) may be critical in Th2 cell recruitment in allergic inflammation; however, the mechanisms of allergen-induced TARC release are unclear. Since airway epithelium is the first line of defense to inhaled allergens, we questioned whether house dust mite allergen (Der p) can induce TARC expression in bronchial epithelial cells, how this is regulated at the molecular level, and if micro-environmental cytokines augment this effect. We examined the effects of Der p and the cytokines IL-4 and TGF-beta on TARC expression in 16HBE cells and primary bronchial asthma epithelium. Real-time PCR and immunofluorescence demonstrated that Der p induces TARC expression in bronchial epithelium. Supernatants from Der p-stimulated 16HBE cells were able to induce TARC-dependent T cell trafficking. IL-4 and TGF-beta cooperatively enhanced Der p-induced TARC expression in 16HBE cells. Specific inhibitors, immunodetection, and gel-shifts revealed that these effects are mediated by phosphorylation of the epidermal growth factor receptor (EGFR), mitogen-activated protein kinase (MAPK) signaling and subsequent nuclear factor (NF)-kappaB activation. A Disintegrin And Metalloproteinase (ADAM), a family of proteins involved in shedding of various growth factors, was shown to be responsible for EGFR activation. The increase in TARC production by direct interaction of Der p with the bronchial epithelium may be an important initial step in the generation of allergic inflammation, which is further potentiated by micro-environmental cytokines. Interference with ADAM or EGFR activity may be a novel promising target to prevent TARC release and subsequent allergic inflammation.     

High interleukin-13 production by phytohaemagglutinin- and Der p 1-stimulated cord blood mononuclear cells is associated with the subsequent development of atopic dermatitis at the age of 3 years

OBJECTIVE: The aim of our study was to conduct a prospective investigation into the potential association of cord blood proliferative response and cytokine production in response to various stimuli on the development of atopic dermatitis (AD) at the age of 3 years. METHODS: Cord blood mononuclear cells (CBMC) from 40 healthy term neonates were isolated. The proliferative response of CBMC stimulated with IL-2, betalactoglobulin (BLG) and house dust mite allergen (Der p 1) was assessed by liquid scintillation counting and the stimulation index (SI) was calculated. The cytokines interleukin (IL-)13, interferon (IFN-)gamma, IL-10 and IL-18 in the cell culture supernatants in response to phytohaemagglutinin (PHA), Der p 1 and BLG were measured using the ELISA technique. After 3 years, symptoms of AD were obtained with a questionnaire completed by the parents. RESULTS: We observed significantly higher IL-13 levels in response to PHA in children who subsequently developed symptoms of AD (S: median, 291 pg/mL) compared with asymptomatic children (No-S: 149 pg/mL; P=0.021, Wilcoxon test). Similarly, in response to Der p 1 significantly higher IL-13 levels were observed in symptomatic children (S: 168.6; No-S: 61.6 pg/mL; P=0.0084). In response to BLG, IL-13 levels were 287.2 (S) and 123.6 pg/mL (No-S; P=0.19). No significant differences were found when comparing the IFN-gamma levels in CBMC cultures stimulated with PHA (S: 10.2; No-S: 17.6 IU/L; P=0.78), Der p 1 (S: 307.6; No-S: 616.2 IU/L; P=0.2) or BLG (S: 18; No-S: 28.5 IU/L; P=0.83; Fig. 2). The IL-18 and IL-10 levels and the stimulation index in response to IL-2, BLG and Der p 1 showed no significant difference between children who subsequently developed symptoms of AD and asymptomatic children. CONCLUSION: Our data suggest that enhanced IL-13 levels at birth are associated with the subsequent development of atopic symptoms at the age of 3 years.