Toll样受体9配体CpG-ODN鼻内应用对变应性联合气道疾病炎性反应的影响

目的:探讨免疫刺激序列Cp G寡聚脱氧核苷酸(Cp G-ODN)鼻内应用与皮下注射对变应性联合气道疾病(ACAD)模型小鼠下气道炎性反应的影响。方法:30只清洁级雌性BALB/c鼠随机分为正常对照组(control组)、变应性鼻炎组(AR组)、变应性联合气道疾病组(ACAD组)、变应性联合气道疾病Cp G-ODN鼻内滴入组(Cp G i.n.组)和变应性联合气道疾病Cp G-ODN皮下注射组(Cp G i.d.组)。实验组动物依次进行腹腔卵白蛋白(OVA)和氢氧化铝凝胶基础致敏和3次鼻腔激发,此后OVA或生理盐水(NS)雾化气道激发,正常对照组则给予NS。Cp G i.n.组和Cp G i.d.组分别给予10.0μg Cp G-ODN滴鼻和皮下注射,其它组给予NS滴鼻或皮下注射。观察Cp GODN干预后对鼻腔及下气道病理变化及评分,并对支气管肺泡灌洗液(BALF)行白细胞分类及嗜酸性粒细胞计数,ELISA法测定BALF和脾脏中细胞因子IL-4、IL-5、IL-13和IFN-γ,以及血清OVA特异性Ig E。结果:炎症细胞浸润评分示ACAD组小鼠肺部的病理改变程度高于control组和AR组(P0.01);Cp G i.n.组炎症评分较ACAD组下降,差异有统计学显著性(P0.05),而Cp G i.d.组炎症评分较ACAD组略有下降,但差异无统计学意义。Cp G i.n.组BALF中的白细胞总数、EOS绝对值计数、EOS百分比、BALF和脾脏淋巴细胞上清液中Th2细胞因子较ACAD组降低,差异具有统计学显著性(P0.01)。Cp G i.d.组上述指标略低于ACAD组,但差异无统计学显著性。Cp G i.n.组血清的OVA特异性Ig E较ACAD组下降,差异有统计学显著性(P0.05),而Cp G i.d.组与ACAD组比较有所下降,但差异无统计学显著性。结论:Cp G-ODN可通过抑制变应性鼻炎而抑制变应性联合气道疾病小鼠的下气道炎性反应,鼻内应用可能较皮下注射更有效。     

The central role of CD30L/CD30 interactions in allergic rhinitis pathogenesis in mice

CD30 ligand (CD30L) plays an important role in the amplification and/or activation of effector CD4(+) T cells, irrespective of Th cell subset. To examine the role of CD30L in allergic rhinitis, we evaluated an OVA model of allergic rhinitis in CD30L knock out (KO) mice on a BALB/c background sensitized with OVA. Symptoms of allergic rhinitis such as eosinophil infiltration into the nasal mucosa were drastically diminished in OVA-sensitized CD30L KO mice following intranasal challenge with OVA. The levels of OVA-specific IgE in the sera and the Th2 response in nasopharynx-associated lymphoid tissues and cervical LNs of CD30L KO mice were significantly lower than those of WT mice following intranasal challenge with OVA. Intranasal administration of CD30-Ig during the effector phase with OVA significantly prevented the development of allergic rhinitis in WT mice. These results suggest that CD30L plays an important role in allergic rhinitis and that the inhibition of CD30L/CD30 signaling might be useful as a novel biological therapy for allergic rhinitis.     

Modification of allergic inflammation in murine model of rhinitis by different bacterial ligands: involvement of mast cells and dendritic cells

BACKGROUND: It has been suggested that airway bacterial infections exacerbate allergic disorders, and bacterial components in the air affect allergic inflammation via Toll-like receptors expressed on mast cells and dendritic cells in the airway mucosa. OBJECTIVE: Peptidoglycan (PGN) is a major component of the bacterial cell wall. We investigated the effect of PGN on the effector phase of allergic inflammation, in comparison with the effect of CpG-oligodeoxynucleotides (CpG), which is known to be a Th1 adjuvant. METHODS: Ovalbumin (OVA)-sensitized mice were challenged intranasally with OVA alone or OVA together with PGN or CpG. Nasal allergic symptoms and eosinophilia were scored, and the OVA-specific cytokine response was examined in the cells of cervical lymph nodes and nasal mucosa. Bone marrow-derived mast cells (BMMCs) and dendritic cells (BMDCs) were stimulated with PGN or CpG in vitro, and the expression level of cytokines and chemokines was examined by RT-PCR. In addition, the expression level of chemokines was examined by RT-PCR in mast cells of OVA-sensitized mice challenged with OVA alone or OVA together with PGN or CpG. RESULTS: PGN exposure exacerbated the nasal allergic symptoms and eosinophilia, whereas CpG exposure suppressed them. In addition, PGN exposure increased the OVA-specific IL-4 response in the cells, whereas CpG exposure decreased it. On the other hand, there were no significant differences in the OVA-specific IFN-gamma response. PGN but not CpG induced the expression of thymus and activation-regulated chemokine (TARC) and macrophage/monocyte-derived chemokine (MDC) in both BMMCs and mast cells of mice sensitized and challenged with OVA. CpG but not PGN induced the expression of IFN-beta and interferon-inducible protein-10 (IP-10) in BMDCs, and histamine did not influence this effect. CONCLUSION: These results demonstrate that PGN exposure exacerbates allergic inflammation mainly via mast cells, whereas CpG exposure suppresses allergic inflammation mainly via dendritic cells.     

Influence of respiratory syncytial virus infection on cytokine and inflammatory responses in allergic mice

BACKGROUND: Th2 lymphocyte responses are associated with inflammation and disease during allergic responses. Exposure to particular environmental factors during the expression of allergy could result in more pronounced Th2-like immune responses and more severe disease. One factor might be a respiratory virus infection. OBJECTIVE: The aim of our study was to investigate the influence of respiratory syncytial virus (RSV) infection on the expression of ovalbumin (OVA)-induced allergy in BALB/c mice. METHODS: We determined OVA-specific IgE in serum, cytokine profiles and histopathological lesions in lungs of OVA-allergic mice after RSV infection. RESULTS: OVA sensitization and challenge induced OVA-specific IgE in serum, Th2 cytokine mRNA expression, and mononuclear and eosinophilic inflammation in the lungs. RSV inoculation during the challenge period enhanced OVA-induced IL-4 and IL-5 mRNA expression in lung tissue. RSV further enhanced the OVA-induced hypertrophy of mucous cells and eosinophilic infiltration in lung tissue. Surprisingly, RSV infection decreased Th2 cytokine secretion and eosinophilic influx in bronchoalveolar lavage of OVA-allergic mice. Because inactivated RSV did not influence these responses, replication of RSV appeared essential for the modification of OVA-induced Th2 cytokine expression. RSV did not change OVA-specific IgE levels in serum. Furthermore, the RSV-induced IL-12 mRNA expression in lung tissue of OVA-allergic mice was diminished, but IFN-gamma mRNA expression was not affected. CONCLUSION: RSV infection enhanced particular OVA-induced Th2 cytokine mRNA responses and pulmonary lesions in allergic mice and thus aggravated allergic respiratory disease.     

Effects of lysedEnterococcus faecalis FK-23 on experimental allergic rhinitis in a murine model

In the current study,we sought to investigate whether lysed Enterococcus faecalis FK-23(LFK),a heat-killed probiotic preparation,attenuated eosinophil influx into the upper airway and had immunomodulatory activity in a murine allergic rhinitis model.Eighteen BALB/c mice were divided into three groups;the ovalbumin(OVA)-sensitized/challenged group,which received saline orally for 6 weeks(OVA group),the OVA-sensitized/challenged group,which received LFK orally for 6 weeks(LFK-fed group),and the non-sensitized group,which received saline for 6 weeks(saline control group).Nasal rubbing and sneezing were monitored during the study.After the final challenge,interleukin(IL)-4,interferon(IFN)-γ,and OVA-specific IgE levels in the sera and splenocyte culture supernatants were determined,eosinophilic infiltrate into the upper airway was quantified,and splenic CD4+CD25+ regulatory T cells(Tregs) were examined by flow cytometry.We found that nasal rubbing was significantly reduced in LFK-fed mice compared to the OVA group on d 27 and 35,and sneezing was significantly inhibited by LFK administration for 35 d.LFK-fed mice had significantly less eosinophil influx into the nasal mucosa than the OVA group.There were no significant differences between the LFK-fed group and OVA group in the serum and splenocyte culture supernatant levels of IL-4,IFN-γ,and OVA-specific IgE.Interestingly,the LFK-fed mice had a significantly greater percentage of splenic CD4+CD25+ Tregs than OVA group.Our results indicate that oral administration of LFK may alleviate nasal symptoms,reduce nasal eosinophilia,and increase the percentage of CD4+CD25+ Tregs in experimental allergic rhinitis.     

Establishment of animal model of antigen-specific T lymphocyte recruitment into nasal mucosa

DO11.10 transgenic mice, expressing an ovalbumin (OVA)-specific alphabeta T-cell receptor (TCR), have been used as a model of various immune diseases associated with T lymphocytes. Some studies of immunoresponse in lung have involved adoptive transfer of DO11.10 mice. As of yet, however, there have been no studies of the adoptive transfer model in the upper airway. The purpose of this study was to establish an animal model to clarify the recruitment mechanism and the roles of Th2 cells in allergic rhinitis. In accordance with the adoptive transfer system, we generated Th0, Th1 and Th2 cells from DO11.10 mice and transferred them into wild type BALB/c mice. Following nasal OVA challenge to DO11.10 mice or to the BALB/c mice into which antigen-specific Th2 cells had been transferred, the number of local antigen-specific TCR-positive cells accompanying the local eosinophilia had significantly increased. However, nasal OVA challenge to BALB/c mice into which antigen-specific Th0 or Th1 cells were transferred failed to increase the number of local OVA-specific TCR positive cells. These observations suggest that an antigen-specific homing mechanism of Th2 cells may exist in nasal mucosa. Analysis of this model will assist in the development of new therapeutic strategy, which targets Th2 cells in allergic rhinitis.     

Lactate dehydrogenase-elevating virus infection at the sensitization and challenge phases reduces the development of delayed eosinophilic allergic rhinitis in BALB/c mice

The present study was conducted to determine whether lactate dehydrogenase-elevating virus (LDV) infection at the sensitization and challenge phases affect the development of delayed allergic eosinophilic rhinitis induced by ovalbumin (OVA) in BALB/c mice (DAR group). Compared to the DAR group, LDV infection at the priming (DAR/LDVs group) and immunizing (DAR/LDVc group) phases reduced the induction of eosinophils in the bone marrow (BM) and/or blood. However, the number of eosinophils in the BM was not affected in the DAR/LDVc group. In addition, total blood IgE values were reduced in the DAR/LDVs but not the DAR/LDVc groups. Compared to the production of cytokines from splenic cells and blood IgE values in the DAR group, OVA-specific IL-4 and IFN-gamma productions and IgE values were reduced in the DAR/LDVs, whereas OVA-specific IFN-gamma and IL-4 productions were increased and decreased, respectively in the DAR/LDVc,but not the DAR/LDVs groups. Both DAR/LDVs and DAR/LDVc groups reduced the development of eosinophilic rhinitis associated with reduced VCAM-1 expression on endothelium in blood vessels and ICAM-1 expression on nasal respiratory epithelium at inflamed areas. The present study suggests that LDV infection at the sensitization phase may reduce the development of T helper (Th) 1 and Th2 responses, whereas LDV infection at the challenge phase may inhibit the development of Th2 response by shifting to Th1 response. These may be responsible for the reduction of the development of DAR by LDV infection.     

Nanomedicine-mediated prevention of inflammatory monocytes infiltration ameliorate ovalbumin-induced allergic rhinitis in mouse model

Abstract

Th2 immune cells infiltration into nasal mucosa is one of the characters of allergic rhinitis (AR). We aimed to explore whether inhibition of Th2 immune cells infiltration would attenuate AR progression. AR mouse model was established by i.p. injection of ovalbumin (OVA). The infiltrated immune cells into nasal lavage fluid were detected by flow cytometry. Cytokine concentration in serum was determined by ELISA. AR mice symptoms were indicated by the number of sneezing and nasal rubbing events. In AR mice, CCL2 expression levels and CD45⁺CD11b⁺Ly6C^hi inflammatory monocytes cells significantly increased as compared with control mice. CCL2 siRNA encapsulated nanoparticles (NP_siCCL2) prevent CCL2 expression and inflammatory monocytes infiltration in AR mice. NP_siCCL2 treatment dramatically decreased the number of sneezing and nasal rubbing events in AR mice. Moreover, NP_siCCL2 treatment attenuated serum OVA-specific IgE, OVA-specific IgG1 and histamine levels. Mechanically, NP_siCCL2 treatment attenuates AR symptoms via inhibiting Th2 cytokine (IL-4, IL-5 and IL-13) production. Nanomedicine-mediated prevention of inflammatory monocytes infiltration ameliorates ovalbumin-induced allergic rhinitis in mouse model.     

Development of a novel Ag-specific immunotherapy using CpG oligodeoxynucleotides in a new, unique mouse cutaneous eosinophilic inflammation model

The number of patients with severe atopic dermatitis (AD) has been on the rise recently. We are therefore urgently in need of a treatment that can suppress Th2 cell-mediated responses in an Ag-specific fashion. Oligodeoxynucleotides (ODN)containing CpG motifs (CpG ODN) have been highlighted as immunomodulators that reduce Th2-mediated responses. To determine the effect of CpG ODN on Th2-mediated skin inflammation, we first developed a reproducible murine model of protein Ag-induced eosinophilic inflammation that is accompanied by epidermal acanthosis and increased serum IgE levels as seen in AD. In this model we found that treatment with CpG ODN during epicutaneous sensitization in previously i.p.-primed mice prevented the development of Th2-mediated responses. Furthermore, to evaluate the therapeutic effect of CpG ODN on established eosinophilic inflammation, mice were treated with a course of the immunotherapy at a skin site remote from the area of Ag application prior to the second 1-wk epicutaneous exposure to Ag. Therapeutic treatment with CpG ODN plus Ag, but not that with CpG ODN alone, could reverse the established eosinophilic inflammation. The presented results provide strong evidence for the feasibility of a novel Ag-specific immunomodulator to treat cutaneous eosinophilic inflammation such as that characteristically found in patients with severe AD.     

Mice vaccinated with allergen-pulsed myeloid dendritic cells are not protected from developing allergen-induced Th2 responses

BACKGROUND: Dendritic cells (DC) play a decisive role in the induction of allergen-induced Th1 and Th2 responses. Since the induction of allergen-specific Th1 responses has shown to inhibit allergen-induced Th2-type inflammation, in this study we investigated whether manipulated myeloid-derived DC pulsed with the specific allergen would predominantly induce allergen-specific Th1 responses thereby reducing the development of Th2 responses. METHODS: Murine bone marrow (BM)-DC were generated and pulsed with ovalbumin (OVA) and CpG oligodeoxynucleotides (CpG-ODN). Langerhans cells (LC) were also isolated and pulsed in vitro with OVA. Subsequently, mice were vaccinated intravenously with either CpG/OVA-pulsed BM-DC or OVA-pulsed LC, and the protocol to induce OVA-specific Th2 responses using OVA/alum sensitization was initiated. Airway inflammation and OVA-specific serum antibody levels were evaluated 6 days after the intranasal challenge with OVA. RESULTS: The application ofCpG/OVA-pulsed BM-DC was unable to reduce airway eosinophilia and inflammation in OVA/alum-immunized mice. OVA-specific IgG1 or IgE serum levels were also not reduced. The experiments using LC pulsed with OVA yielded similar results. However, mice vaccinated with CpG/OVA-pulsed BM-DC had greatly enhanced levels of serum OVA-specific IgG2a, suggesting the induction of allergen-specific Th1 responses in vivo. Moreover, allergen-induced mast cell degranulation was decreased using this approach. CONCLUSIONS: Taken together, our results demonstrated that the vaccination with OVA-pulsed BM-DC matured with CpG-ODN or OVA-pulsed LC did not result in a reduction in allergen-specific Th2 responses in a murine model of severe atopic asthma. Other DC-based vaccination strategies should be evaluated in order to prevent the development of allergic disorders.     

Oral administration of CpG-ODNs suppresses antigen-induced asthma in mice

Oligodeoxynucleotides containing CpG motifs (CpG-ODNs) can protect against eosinophilic airway inflammation in asthma. Previously we have found that parenteral or mucosal administration of CpG-ODNs is effective in preventing (as well as reversing established) disease. In this study, we examined the effect of oral CpG-ODNs on the development of immune tolerance. Using an ovalbumin (OVA)-induced murine model of asthma, we found that CpG-ODNs, administered orally around the time of sensitization, prevented eosinophilic airway inflammation in a dose-dependent manner. Although oral co-administration of CpG-ODNs with OVA (known to induce tolerance) did not significantly change the inhibition of OVA-induced airway eosinophilia, it did modulate OVA-specific immunoglobulin responses: oral administration of OVA alone suppressed OVA-specific IgG1 production, but only mice that received CpG-ODNs demonstrated enhanced levels of OVA-specific IgG2c. Finally, we examined whether oral administration of CpG-ODNs, alone or with OVA, could reverse established eosinophilic airway inflammation. Again, neither OVA nor CpG-ODNs alone modulated established eosinophilic airway inflammation, but a combination of the OVA and CpG-ODNs successfully desensitized the mice. This desensitization was associated with suppression of OVA-specific IgE and enhancement of OVA-specific IgG2c production. These findings provide the first indication that oral administration of CpG-ODNs is effective in preventing and reversing antigen-induced eosinophilic airway inflammation. CpG-ODNs may be useful as a component of oral immunotherapy to promote tolerance in established asthma.     

Mast cell regulation of epithelial TSLP expression plays an important role in the development of allergic rhinitis

Epithelial cell-derived thymic stromal lymphopoietin (TSLP) is a master switch for asthma or atopic dermatitis by inducing a dendritic cell-mediated Th2-type allergic inflammation. Allergic rhinitis is also pathologically characterized by Th2-type allergic inflammation. This study demonstrates that mast cells regulate the epithelial TSLP expression in allergic rhinitis. TSLP expression was found to be up-regulated predominantly in the nasal epithelium in the ovalbumin (OVA)-sensitized and -nasally challenged mouse model of allergic rhinitis, which was abolished in mast cell-deficient WBB6F1-W/W(v) in comparison with control WBB6F1-+/+ mice. Similarly, the epithelial TSLP expression was reduced in Fc receptor gamma chain (FcgammaR)-deficient mice, where the high-affinity IgE receptor (FcepsilonRI) is not expressed on mast cells, in comparison with control C57BL/6 mice. Furthermore, the administration of neutralizing TSLP antibody during the challenge phase of OVA inhibited the development of allergic rhinitis. These results suggest that the direct stimulation of epithelial cells by antigens alone may not be sufficient to induce TSLP expression in the nasal epithelium, and that mast cell regulation of epithelial TSLP expression, possibly via FcepsilonRI, plays an important role in the development of allergic rhinitis.     

TNF-alpha contributes to the development of allergic rhinitis in mice

BACKGROUND: Allergic rhinitis is an inflammation involving T(H)2-type cytokine production, with pathologic eosinophil infiltration in the nasal mucosa. Although TNF-alpha is thought to be a pro-inflammatory cytokine, the relationship between TNF-alpha and allergic rhinitis has not been clarified. OBJECTIVES: The role of TNF-alpha in a murine model of ovalbumin (OVA)-sensitized allergic rhinitis was investigated by using mice deficient in the gene encoding TNF-alpha (TNF-alpha(-/-) mice). METHODS: Both wild-type (TNF-alpha(+/+)) and TNF-alpha(-/-) mice were sensitized with OVA by means of intraperitoneal injection. They were then challenged with intranasal OVA, and various allergic responses were assessed. RESULTS: The production of OVA-specific IgE in the serum (P <.05) and the frequency of sneezes (P <.05) and nasal rubs (P <.05) decreased significantly in TNF-alpha(-/-) mice after OVA sensitization compared with that in TNF-alpha(+/+) mice (P <.05). The mRNA expression of IL-4, IL-10, and eotaxin in nasal mucosa in TNF-alpha(-/-) mice was also significantly suppressed compared with that in TNF-alpha(+/+) mice after OVA sensitization (P <.05). Furthermore, the expression of both endothelial-leukocyte adhesion molecule 1 and vascular cell adhesion molecule 1 mRNA in the nasal mucosa was significantly suppressed (P <.05), although intercellular adhesion molecule 1 mRNA expression did not decrease significantly in TNF-alpha(-/-) mice compared with that in TNF-alpha(+/+) mice after OVA sensitization. In addition, the effect of TNF-alpha on endothelial-leukocyte adhesion molecule 1 and vascular cell adhesion molecule 1 expression by means of Western blot analysis was compatible with the mRNA results. Pathologically, eosinophil infiltration in nasal mucosa was significantly restricted in TNF-alpha(-/-) mice compared with in TNF-alpha(+/+) mice after OVA sensitization (P <.05). CONCLUSION: TNF-alpha is necessary for antigen-specific IgE production and for the induction of T(H)2-type cytokines and chemokines. Furthermore, TNF-alpha might be important for the expression of adhesion molecules to recruit eosinophils to the allergic inflammatory site. We conclude that the lack of TNF-alpha inhibited the development of allergic rhinitis.     

Ameliorative effect of acetylshikonin on ovalbumin (OVA)‐induced allergic rhinitis in mice through the inhibition of Th2 cytokine production and mast cell histamine release

Acetylshikonin has long been known as an anti‐inflammatory and antioxidative reagent. However, the anti‐allergic effect has not been studied. The aim of this study was to evaluate the effect of acetylshikonin on allergic rhinitis (AR) in mice. Mice were sensitized by intraperitoneal injection of OVA and aluminum hydroxide and challenged with intranasal instillation of OVA. Acetylshikonin was administered orally after nasal cavities challenge. Severity of allergic rhinitis was assessed according to nasal symptoms; serum OVA‐specific immunoglobulin E (IgE), IgG1, and IgG2a level; and interleukin (IL)‐4, IL‐10, IL‐5, IL‐13, TNF‐α, IL‐12, and interferon (INF)‐γ levels in nasal lavage fluid (NALF). Additionally, the histological change and the release of histamine in serum and nasal lavage fluid were evaluated by acid‐Schiff stain and ELISA. Acetylshikonin attenuated manifestation of nasal symptoms in sensitized mice and inhibited production of Th2‐related OVA‐specific IgE, IgG1, and Th2 cell‐produced IL‐4, IL‐5, IL‐13, and mast cell produced histamine; however, it had no effect on Th1 cell‐produced cytokines, like INF‐γ. In addition, the degree of inflammatory cell infiltration and goblet cell hyperplasia was attenuated by acetylshikonin treatment. Our results suggest that acetylshikonin effectively reduces allergic inflammation in a mouse model of allergic rhinitis by its anti‐allergic and anti‐inflammatory properties.     

克鼻敏汤剂对实验性变应性鼻炎大鼠细胞因子水平的调节作用

研究中药复方克鼻敏汤剂对实验性变应性鼻炎大鼠的治疗作用,并初步探讨其机制。用卵清蛋白致敏大鼠制作变应性鼻炎动物模型,并经灌胃克鼻敏进行预防性治疗。观察变应性鼻炎大鼠行为学改变;组织病理学方法观察鼻黏膜改变;采用ELISA法检测血清总IgE、卵清蛋白特异性IgE和细胞因子IFN-γ、IL-2、IL-4及IL-5水平。结果发现与模型对照组比较,克鼻敏治疗组行为学积分、血清总IgE和特异性IgE含量,IL-4和IL-5水平均明显下降(P<0.01);血清IL-2和IFN-γ明显升高(P<0.01)。克鼻敏治疗组与药物对照组和正常对照组比较,IFN-γ、IL-4和IL-5水平均无显著性差异,但克鼻敏治疗组行为学积分、血清总IgE和特异性IgE含量及IL-2水平均高于药物对照组和正常对照组。克鼻敏治疗组与强的松治疗组比较各项观测指标均无显著性差异。研究结果提示中药复方克鼻敏汤剂可通过调节细胞因子表达,下调IgE的产生达到对实验性变应性鼻炎的治疗目的。     

Allergen-independent immunostimulatory sequence oligodeoxynucleotide therapy attenuates experimental allergic rhinitis

While effective for the prevention and treatment of allergic rhinitis (AR) symptoms, currently available medications do not reverse allergen specific hypersensitivities. Therefore, pharmacotherapeutics are not curative and their daily use is often required for years. These investigations were conducted to determine whether immunostimulatory sequence oligodeoxynucleotide (ISS-ODN) delivery protects previously sensitized mice from AR hypersensitivity responses and modulates their allergen specific immune profiles. Mice were first sensitized with ovalbumin (OVA) and alum, twenty-four hr before beginning a series of seven daily intranasal (i.n.) allergen challenges, subsets of mice received a single i.n. or intradermal (i.d.) dose of ISS-ODN or control oligodeoxynucleotide (C-ODN), a single intraperitoneal (i.p.) injection of dexamethasone (DXM), or no intervention. Mice receiving i.d. or i.n. ISS-ODN were found to have attenuated immediate and late phase effector cell responses to i.n. OVA challenge. Specifically, ISS-ODN treated mice had less histamine and cysteinyl leukotriene release and eosinophilic inflammation in their nasal passages than mice treated with C-ODN. In addition, splenocytes from ISS-ODN but not C-ODN treated mice displayed attenuated OVA-specific interleukin (IL)-4, IL-5, and IL-13 but increased interferon-gamma responses. Finally, ISS-ODN was generally a more effective treatment than DXM, both in blunting AR hypersensitivity responses and in shifting T helper 2 Th2-biased immune parameters towards Th1 dominance. As ISS-ODN delivery rapidly attenuated effector cell responses in this AR model in an allergen independent manner, the present results suggest that therapy with ISS-ODN alone may be an effective alternative to corticosteroid medications for the clinical management of AR.     

Inhibition of Airway Allergic Disease by Co-Administration of Flagellin with Allergen

Bacterial flagellin, which activates Toll-like receptor 5 and cytosolic pattern recognition receptor Ipaf, has a strong immunomodulatory activity. In the present study, we examined whether intranasal co-administration of flagellin with allergen could modulate established airway hyperresponsiveness and Th2 response using an ovalbumin (OVA)-sensitized mouse model. Balb/c mice sensitized with OVA were treated with OVA–flagellin (FlaB) mixture three times at 1-week intervals. Seven days after the final OVA–FlaB administration, the mice were challenged with OVA inhalation, and airway responses and OVA-specific immune responses were evaluated. The OVA–FlaB treatment significantly suppressed OVA-induced airway hyperresponsiveness, airway eosinophilic inflammation, and OVA-specific Th2 cytokine productions in splenocytes. These results indicate that flagellin co-administered with allergen can modulate airway inflammatory response through inhibition of Th2 responses, and flagellin can be considered as a component for allergen-specific immunotherapy.     

Topical CTLA4-Ig suppresses ongoing mucosal immune response in presensitized murine model of allergic rhinitis.

Allergic rhinitis is thought to be mediated by CD4+ T cells producing Th2-associated cytokines. Optimal Ag-specific T-cell activation requires the engagement of T-cell receptor with antigen (Ag) in the context of MHC, and the engagement of appropriate costimulatory molecules. One of the most well-characterized costimulatory pathways is the interaction of B7/CD28-CTLA4 molecules. Recent studies have suggested that the costimulatory pathway may influence the development of Th2 immune responses. The objective of this study was the examination of the role of B7/CD28-CTLA4 costimulatory pathway in the pathogenesis of ovalbumin (OVA)-induced immune response in presensitized murine model of allergic rhinitis. Systemically presensitized BALB/c mice significantly developed Ag-induced early phase nasal symptoms, nasal hyperresponsiveness to histamine, nasal eosinophilia, serum levels of OVA- specific IgE and Th2-associated cytokines following repeated topical Ag challenges. Topical administration of CTLA4-Ig during nasal challenges inhibited Ag-induced nasal symptoms and histamine hyperresponsiveness. We also found a significant reduction in nasal lavage eosinophilia and serum levels of OVA-specific IgE. Furthermore, CTLA4-Ig treatment significantly decreased interleukin (IL)-4 content in nasal tissue, while there was no significant change in IL-5 or IFN-gamma levels. These results suggest that B7/CD28-CTLA4 costimulatory pathway mediates the development of ongoing Th2 immune responses and plays a major role in regulating allergic disease, such as allergic rhinitis.     

Attenuated Salmonella typhimurium reduces ovalbumin-induced airway inflammation and T-helper type 2 responses in mice

Cytokines produced by Th2 cells are responsible for the pathogenesis of asthma. Th1-biased immune responses caused by attenuated salmonella have the potential to relieve asthmatic symptoms. We evaluated whether oral administration of attenuated salmonella could modulate allergic responses in a chicken ovalbumin (OVA)-induced asthmatic murine model. Mice were fed with attenuated salmonella SL7207 one dose before and three doses during the induction of an allergic response. Lung histology, percentages of eosinophil in bronchoalveolar lavage fluid, serum levels of OVA-specific antibodies and cytokine production by OVA-activated splenocytes were evaluated in mice with or without the administration of SL7207. A significant reduction in pulmonary eosinophilic infiltration was observed in mice receiving attenuated salmonella. Lower levels of OVA-specific IgG1 but higher titres of OVA-IgG2a in serum were also detected in this group. Splenocytes from salmonella-fed mice produced lower levels of Th2 cytokines upon OVA stimulation. The administration of attenuated salmonella significantly suppressed immunopathological symptoms in OVA-sensitized mice. Inhibition of Th2 responses might explain the potential mechanisms. This study provides some evidence for the feasibility of attenuated salmonella as an effective vaccine for allergic diseases.