Vaccinations with T-helper type 1 directing adjuvants have different suppressive effects on the development of allergen-induced T-helper type 2 responses

BACKGROUND: Allergen-induced T-helper type 2 (Th2) responses can be inhibited with Th1 directing vaccines. However, studies comparing the efficacy of the different adjuvants have not been performed in detail. OBJECTIVE: For this reason we compare the effects of live Bacillus-Calmette-Guerin(BCG), heat-killed (hk)-BCG, CpG-ODN (oligodeoxynucleotide) or PPD on the development of allergen-induced Th2 responses in mice. METHODS: Ovalbumin (OVA)-specific allergic responses were induced in C57BL/6 mice by two intraperitoneally (i.p.) applications of OVA/alum followed by the intranasal challenge with OVA. The different Th1-inducing adjuvants were applied to the mice together with OVA/alum i.p. during the OVA-sensitization period and, subsequently, different parameters of allergic immune responses were evaluated. RESULTS: All the adjuvants were effective in inhibiting the development of allergen-induced airway eosinophilia, mucous production and, with the exception of PPD, also airway hyper-reactivity, when they were applied together with OVA/alum. However, allergen-specific IgG1 and IgE serum levels were only reduced in live BCG- and PPD-treated mice. Suppression of airway eosinophilia was not observed in IFN-gamma- or IL-12-deficient mice (hk-BCG, CpG-ODN and PPD). Interestingly, live BCG was still able to suppress allergen-induced Th2 responses in the absence of either IFN-gamma or IL-12. When mice vaccinated with the different adjuvants together with OVA/alum were subjected to a second period of OVA/alum immunization, only live and hk-BCG were able to efficiently suppress the development of airway inflammation. This effect could be adoptively transferred by splenic CD4(+) T cells. CONCLUSIONS: Taken together our data suggest that live BCG>hk-BCG>CpG-ODN >PPD are effective in suppressing allergen-induced Th2 responses. The degree of suppression and the component of the Th2 response affected (airway inflammation vs. the production of allergen-specific IgE and IgG1) were dependent upon the adjuvant used and how it was applied. Our results contribute to the design of novel vaccines protecting humans from developing allergic disorders.     

Interleukin-10-treated dendritic cells do not inhibit Th2 immune responses in ovalbumin/alum-sensitized mice

BACKGROUND: It is well known that the immunoregulatory cytokine interleukin (IL)-10 inhibits the accessory function of human dendritic cells (DC) in vitro. Recently, we have shown that these IL-10 DC inhibit the production of T helper cell 1 (Th1) and T helper cell 2 (Th2) cytokines by T cells from atopic individuals in vitro. The current study was set out to analyze whether IL-10 DC also exert inhibitory effects in vivo in a murine model of allergy to ovalbumin adsorbed to the adjuvant aluminium hydroxide (OVA/alum). METHODS: OVA-pulsed or unpulsed bone marrow-derived DC, treated with IL-10 or left untreated during generation, were injected intravenously into BALB/c mice prior to and during OVA/alum sensitization, and sera and immune responses of mesenterial lymph node cells were analyzed. Additionally, bronchoalveolar lavage was performed after intranasal challenge with OVA. RESULTS: Treatment of BALB/c mice with OVA-pulsed DC led to a significantly enhanced proliferation as well as Th2 (IL-4, IL-5), Th1 (interferon-gamma) and IL-10 cytokine production after restimulation of lymph node cells with OVA in vitro compared with OVA immunization alone. In contrast, using OVA-pulsed IL-10 DC for transfer, proliferation and cytokine production by lymph node cells were not enhanced. OVA-specific immunoglobulin G1 (IgG1) and IgG2a production were significantly increased after transfer of OVA-pulsed DC and OVA-pulsed IL-10 DC, respectively, whereas anti-OVA IgE production and airway eosinophilia remained unchanged. CONCLUSIONS: Our data indicate that IL-10 treatment of DC decreases the Th1 and Th2 stimulatory capacity of DC but does not actually inhibit systemic (IgE) and local (airway inflammation) allergen-specific immune responses in a murine model of allergy.     

Neonatal vaccination with Bacillus Calmette-Guérin elicits long-term protection in mouse-allergic responses

Background:  Mycobacterium bovis Bacillus Calmette-Guérin (BCG) vaccination has been shown to inhibit allergic airway inflammation in animal models, associated with the regulation of allergen-specific T-cell immunity. However, little is known about whether neonatal BCG treatment could inhibit allergic inflammation by regulating allergen-specific T-cell response in aged mice. This study was aimed to investigate the impact of neonatal BCG treatment on allergic asthma and possible mechanism(s) underlying the action of BCG in different ages of mice.
Methods:  C57BL/6 neonates were vaccinated with BCG on days 1, 7 and 14, sensitized with ovalbumin (OVA) at 5 and 7 weeks of age, and then challenged with allergen at 9 or 45 weeks of age for early- or late-challenged asthma. Their airway inflammation and allergen-specific T-cell responses were characterized.
Results:  Following early-challenge, BCG vaccination inhibited airway hyper-responsiveness (AHR), infiltration of eosinophils and mucous overproduction ( P  <   0.05), and shifted OVA-specific predominant Th2- to Th1-type cytokine responses in both the bronchoalveolar lavage fluid and the splenocyte supernatants ( P  <   0.05). In late-challenged mice, neonatal BCG treatment attenuated AHR and eosinophilia ( P  <   0.05), but failed to modulate allergen-specific cytokine responses.
Conclusions:  Our data suggest that neonatal BCG vaccination has a long-term effect on inhibiting AHR and eosinophilia, which is associated with the modulation of Th1/Th2 cytokine production in early-, but not in late-challenged mice. Thus, different mechanisms may mediate the long-term protective effect of BCG neonatal vaccination differently in younger adult and aged mice.     

Intranasal delivery of whole influenza vaccine prevents subsequent allergen-induced sensitization and airway hyper-reactivity in mice

BACKGROUND: Infection with influenza virus has been associated with seemingly opposing effects on the development of asthma. However, there are no data about the effects of mucosal vaccination with inactivated influenza on the inception of allergic asthma. OBJECTIVE: To assess the immunological effects of inhaled inactivated influenza vaccine, using two different types of flu vaccines, on the inception of allergic sensitization and allergen-mediated airway disease in a mouse model. METHODS: BALB/c mice were intranasally or intratracheally vaccinated with whole or split influenza virus vaccine (days -1 or -1, 27) before systemic sensitization with ovalbumin (OVA) (days 1, 14) and repeated airway allergen challenges (days 28-30). Allergen sensitization (IgE serum levels), airway inflammation (differential cells in bronchoalveolar lavage fluid) and airway hyper-reactivity (AHR) (in vivo lung function) were analysed. RESULTS: The intranasal instillation of whole influenza vaccine before allergen sensitization significantly reduced the serum levels of total and OVA-specific IgE as well as allergen-induced AHR. Prevention was due to an allergen-specific shift from a predominant T helper (Th)2- towards a Th1-immune response. Application of split influenza vaccine did not show the same preventive effect. CONCLUSION: Intranasal administration of inactivated whole influenza vaccine reduced subsequent allergen sensitization and prevented allergen-induced AHR. Our results show that the composition of the influenza vaccine has a major influence on subsequent development of allergen-induced sensitization and AHR, and suggest that mucosal inactivated whole influenza vaccination may represent a step towards the development of a preventive strategy for atopic asthma.     

Mechanisms preventing allergen-induced airways hyperreactivity: role of tolerance and immune deviation

BACKGROUND: Aeroallergens continuously enter the respiratory tract of atopic individuals and provoke the development of asthma characterized by airway hyperreactivity (AHR) and inflammation. By contrast, nonatopic individuals are exposed to the same aeroallergens, but airway inflammation does not develop. However, the mechanisms that prevent allergen-induced respiratory diseases in nonatopic subjects are poorly characterized. OBJECTIVE: In this study we compared the role of allergen-specific T-cell tolerance and immune deviation in conferring protection against the development of allergen-induced AHR. METHODS: We exposed mice to intranasal ovalbumin (OVA) to induce T-cell tolerance and examined its effects on the subsequent development of AHR and inflammation. RESULTS: We demonstrated that exposure of mice to intranasal OVA resulted in peripheral CD4(+) T-cell unresponsiveness that very efficiently prevented not only the development of AHR but also greatly inhibited airway inflammation and OVA-specific IgE production. The induction of peripheral T-cell tolerance and protection against AHR were not dependent on the presence of IFN-gamma or IL-4. The development of AHR was also prevented by an OVA-specific T(H)1-biased immune response induced by inhalation of OVA in the presence of IL-12. However, the OVA-specific T(H)1 response was associated with a significant degree of pulmonary inflammation. CONCLUSION: These results indicate that both allergen-specific T-cell tolerance and T(H)1-biased immune deviation prevent the development of AHR, but T(H)1 responses are associated with significantly greater inflammation in the lung than is associated with T-cell unresponsiveness. Therefore CD4(+) T-cell unresponsiveness critically regulates immune responses to aeroallergens and protects against the development of allergic disease and asthma.     

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。     

Systemic Administration of Olygodeoxynucleotides with CpG Motifs at Priming Phase Reduces Local Th2 Response and Late Allergic Rhinitis in BALB/c Mice

Oligodeoxynucleotides (ODN) with CpG motifs (CpG ODN) induce T helper (Th)1-type reaction. We aimed to evaluate the therapeutic effect of CpG ODN in the development of late allergic rhinitis induced by ovalbumin (OVA), which is one of Th2 diseaes, in BALB/c mice. Effects of a single dose of synthetic CpG-ODN (50 μg) intraperitoneally (i.p.) at the priming phase (on day 0) by OVA on the development of late eosinophilic rhinitis at respiratory areas were compared to the control mice treated with its vehicle (ODN without CpG motifs; 50 μg). Animals were again sensitized by OVA (on day 10) i.p., and 4 days after second sensitization animals were challenged by OVA intranasally (on day 14). Four days after challenge, eosinophilic reactions, nasal lesions and local cytokine values were examined. Compared to the control group, the CpG ODN-administration increased production of OVA-specific Th1 cytokine (interferon-γ) and decreased productions of ovalubmin-specific Th2 cytokines [interleukin (IL)-5 and IL-13] in nasal cavity fluids, supernatants of splenocytes and/or sera. Also, eosinophilia and increased total IgE values were decreased in mice treated with the CpG ODN compared to the control group. Moreover, nasal lesions with infiltration of eosinophils were prominently reduced by the CpG ODN-treatment compared to the control mice. The present study suggests that the systemic administration of CpG ODN at the priming phase may reduce local OVA-specific Th2 responses, resulting in decreased nasal pathology in the late allergic eosinophilic rhinitis. The authors wish it to be known, in their opinion, Toshiharu Hayashi and Keiko Hasegawa contributed equally to this work.     

Effect of neonatal sublingual vaccination with native or denatured ovalbumin and adjuvant CpG or cholera toxin on systemic and mucosal immunity in mice

Sublingual immunotherapy has been applied for allergic diseases, but whether sublingual immunization in neonates can prevent sensitization has not been studied. In this study, we evaluate the effect of neonatal sublingual vaccination with native or denatured allergens alone or plus adjuvant on allergy prevention. Newborn BALB/ c mice were sublingually vaccinated daily for the first 3 days with native or denatured ovalbumin (OVA) only, or combined adjuvant CpG or cholera toxin (CT). They were sensitized with OVA adsorbed onto alum 7 weeks after the last vaccination. Specific secretory IgA antibody responses were readily induced by neonatal vaccination with antigen plus CpG or CT, but not with antigen alone. Whereas vaccination with denatured OVA plus CpG markedly enhanced T helper 1 (Th1) responses and inhibited IgE production, vaccination with denatured OVA plus CT increased cervical lymph node cell production of interleukin-4 (IL-4), IL-5, IL-6, and serum IgG1 responses. These data demonstrate that neonatal sublingual vaccination with denatured OVA and CpG not only preferentially induces systemic Th1 responses and mucosal immunity, but also simultaneously abrogates IgE production. Neonatal sublingual vaccines may play a role for the strategy of allergy prevention.     

Impairment of dendritic cell function by excretory-secretory products: a potential mechanism for nematode-induced immunosuppression

To determine whether helminth-derived products modulate dendritic cell (DC) function, we investigated the effects of excretory-secretory products (ES) and adult worm homogenate (AWH) derived from the gastrointestinal nematode Heligmosomoides polygyrus (Hp) on murine bone marrow-derived DC (BMDC). Compared to the TLR9 ligand CpG, Hp-derived products alone failed to induce DC activation. ES, but not AWH, inhibited BMDC cytokine and chemokine production and co-stimulatory molecule expression (CD40, CD86 and MHC class II) induced by TLR ligation. TLR ligand-independent, PMA-induced DC activation was unaffected by ES. Recipients of ES-treated BMDC pulsed with OVA had suppressed Ab responses in vivo, irrespective of the Th1 or Th2 isotype affiliation, compared to recipients of control OVA-pulsed BMDC. Importantly, suppression occurred even in the presence of the potent type 1 adjuvant CpG. In contrast to untreated OVA-pulsed BMDC, ES-treated BMDC pulsed with OVA had reduced co-stimulatory molecule and cytokine expression. CD4(+)CD25(+)Foxp3(-) T cells, which secreted high IL-10 levels, were generated in co-cultures of OT-II OVA-specific TCR-transgenic CD4(+) T cells and ES-treated BMDC. These IL-10-secreting T cells suppressed effector CD4(+) T cell proliferation and IFN-gamma production, the latter effect mediated by an IL-10-dependent mechanism. Together, these results demonstrate that nematode ES impaired DC function and suppressed both Th1 and Th2 adaptive immune responses possibly by inducing regulatory T cells.     

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.     

Common vaccine antigens inhibit allergen-induced sensitization and airway hyperresponsiveness in a murine model

BACKGROUND: Co-vaccination with cellular pertussis vaccine down-regulates allergic sensitization to diphtheria and tetanus antigens. Using a murine model, we investigated whether vaccination with diphtheria/tetanus toxoids, administered separately or simultaneously with the whole cell vaccine of Bordetella pertussis, inhibits subsequent allergen-induced immune and inflammatory responses. METHODS: BALB/c-mice were vaccinated intracutaneously with a combination of diphtheria and tetanus toxoids or a combination of diphtheria and tetanus toxoids with a whole cell vaccine of B. pertussis (three times, days -21 to -7) prior to systemic sensitization (days 1-14) and repeated airway challenges (days 28-30) with ovalbumin. RESULTS: Compared with negative controls, systemic sensitization and airway allergen challenges induced high serum levels of allergen-specific IgE, predominant Th2-type cytokine production, airway inflammation and development of in vivo airway hyperreactivity. Vaccination with diphtheria and tetanus toxoids prior to sensitization suppressed IgE formation and development of eosinophilic airway inflammation. Co-vaccination with a whole cell pertussis vaccine inhibited allergen sensitization, airway inflammation and development of in vivo airway hyperreactivity. Prevention was due to an allergen-specific and general shift from a predominant Th2 towards a predominant Th1 immune response. CONCLUSION: Vaccination with diphtheria and tetanus toxoids alone or in combination with whole cell pertussis vaccine prior to allergen sensitization prevented allergen-induced Th2 immune responses. Vaccine antigens may down-regulate allergic responses to a range of common allergens.     

Orally administered OVA/CpG-ODN induces specific mucosal and systemic immune response in young and aged mice

We have previously demonstrated that subcutaneously administered ovalbumin (OVA) plus synthetic oligodeoxynucleotides containing immunostimulatory CpG motifs (CpG-ODN) as adjuvant stimulate cellular and humoral immunity and promote T helper cell type 1 differentiation in aged mice. The present study assessed the ability of CpG-ODN to induce an OVA-specific immune response after oral immunization in young (3-month-old) and aged (18-month-old) BALB/c mice. Oral OVA/CpG-ODN immunization induces a similar OVA-specific T cell-proliferative response (in mucosal and systemic tissues), immunoglobulin G (IgG) in plasma, and IgA in intestinal washes in both groups of ages. The OVA-specific humoral immune response observed in aged mice was similar to the one observed in young mice, peaking at day 7 after the last oral immunization and was present over 40 days after the last oral immunization. The pattern of cytokines released in culture supernatants in both groups of mice was similar, with specific interferon-gamma secretion in the absence of interleukin-5 responses. These results provide evidence that orally administered OVA/CpG-ODN induces a young-like, specific, immune response against OVA in aged mice, showing that CpG-ODN might be used as a mucosal adjuvant during aging.     

Blockade of CTLA-4 promotes airway inflammation in naive mice exposed to aerosolized allergen but fails to prevent inhalation tolerance

In subjects not developing allergy, inhalation of nonpathogenic protein antigens causes no harm and is associated with tolerance induction. Repeated exposure to aerosolized ovalbumin (OVA) likewise does not evoke airway inflammation and induces inhalation tolerance in experimental animals. The present study explored the role of the inhibitory T-cell receptor CTLA-4, in preventing inflammation and in establishing inhalation tolerance in response to a protein antigen. Naive BALB/c mice were injected intraperitoneally with anti-CTLA-4 monoclonal antibody or control immunoglobulin G (IgG) and exposed daily to aerosolized saline or OVA over 10 or 20 consecutive days. OVA-specific IgE levels and the inflammatory response in airway tissues were assessed 2 days after last exposure. The OVA-specific IgE response was also evaluated in mice subjected to a subsequent immunogenic OVA challenge 18 days after last aerosol exposure. Additional mice were made tolerant by 10 days of OVA aerosol exposure and were then subjected to an immunogenic OVA challenge combined with CTLA-4 blockade or control IgG treatment. Repeated inhalation of aerosolized OVA alone did not cause a pulmonary inflammatory response. In contrast, 10 days of OVA exposure combined with blockade of CTLA-4 led to development of eosinophilic lung infiltrates, BAL fluid eosinophilia, goblet cell hyperplasia and increased OVA-specific IgE. By 20 days of OVA exposure and blockade of CTLA-4, the inflammatory response remained. Mice exposed to aerosolized OVA for 10 days exhibited greatly reduced OVA-specific IgE responses to subsequent immunogenic OVA challenge. Blockade of CTLA-4 during the period of OVA aerosol exposure did not prevent this suppression of the OVA-specific IgE response. Neither did blockade of CTLA-4 during immunogenic OVA challenge alter the allergen-specific IgE response. Our results indicate that in vivo blockade of CTLA-4 modulates the initial immune response to a protein antigen allowing the development of allergen-induced airway inflammation in naive mice. However, this initial exaggerated immune response is followed by the induction of inhalation tolerance, demonstrating that CTLA-4 signalling is not decisive in this process. Our findings also show that once inhalation tolerance is established it may not be disrupted by blockade of CTLA-4.     

Lipopolysaccharide inhalation exacerbates allergic airway inflammation by activating mast cells and promoting Th2 responses

BACKGROUND: Bacterial infection occasionally exacerbates asthma, although the cellular and molecular mechanisms have not been well defined. An involvement of mast cells has been suggested, as lipopolysaccharides (LPS)-induced cytokine production from mast cells in vitro. OBJECTIVE: This study was undertaken to examine the effects of LPS inhalation on mast cell functions and allergen-specific immune responses in a murine model of asthma. METHODS: Female BALB/c mice or mast cell-deficient W/W(v) mice were immunized intraperitoneally with ovalbumin (OVA). Mice were challenged with aerosolized OVA or OVA with LPS daily from day 21 to day 24. Twenty-four hours after the last challenge, airway inflammation and OVA-specific immune responses were examined. Allergen-specific T cell responses were further analysed by adoptively transferring OVA-specific CD4(+) T cells. Expression of chemokines in the lung was also examined. RESULTS: LPS inhalation with OVA resulted in exacerbated airway infiltration, which was not evident in mast cell-deficient mice. IL-5 production by mast cells in the lung was enhanced by LPS inhalation. OVA-specific IgE production as well as proliferation, cytokine production and local infiltration of OVA specific T-helper lymphocytes type 2 (Th2) were also enhanced. Up-regulated expression of Th2- and/or eosinophil-attracting chemokines was observed in the lung of mice inhalated with LPS. CONCLUSIONS: LPS inhalation exacerbates airway inflammation, which is accompanied by mast cell activation and enhanced Th2 responses. These observations provide clues towards understanding the mechanisms of bacterial infection-induced exacerbation of the clinical features of asthma.     

Effect of sublingual administration with a native or denatured protein allergen and adjuvant CpG oligodeoxynucleotides or cholera toxin on systemic T(H)2 immune responses and mucosal immunity in mice.

BACKGROUND: Sublingual immunotherapy has been recently used for allergic diseases, but its mechanisms are still unclear. OBJECTIVE: To examine the effect of sublingual administration of a native or denatured allergen alone or plus adjuvant on systemic T(H)2 responses and mucosal immunity in mice. METHODS: Naive or sensitized BALB/c mice were sublingually vaccinated biweekly for 3 weeks with ovalbumin (OVA) or urea-denatured OVA (CM-OVA) only or plus adjuvant CpG oligodeoxynucleotides (CpG) or cholera toxin (CT). Two weeks later, their specific serum IgG, IgG1, IgG2a, IgE, and saliva secretory IgA (SIgA) antibody responses and the cytokine profiles of spleen and cervical lymph node cells were investigated. RESULTS: Specific SIgA antibody responses were induced by vaccination with CM-OVA plus CpG or CT. Whereas vaccination with CM-OVA and CpG enhanced T(H)1 responses but inhibited IgE production, vaccination with CT and CM-OVA or OVA increased cervical lymph node cell production of interleukin (IL) 4, IL-5, and IL-6 and serum IgG1 antibody responses. In previously sensitized mice, sublingual vaccination with OVA or CM-OVA plus CT or CpG stimulated mucosal SIgA antibody responses, but did not enhance ongoing IgE antibody responses. CONCLUSIONS: Sublingual vaccination with OVA or CM-OVA plus adjuvant CT or CpG all can induce systemic and mucosal immunity, but CM-OVA plus CpG had the best prophylactic and therapeutic effects on IgE antibody production. It is likely that sublingual vaccines may have a role for the prophylaxis and immunotherapy of allergic reactions.     

OVA-Fc融合基因疫苗对哮喘小鼠的疗效观察

目的探讨OVA-Fc融合基因疫苗治疗哮喘小鼠气道炎症和气道高反应性的效果。方法分别将制备的OVA-Fc-pcDNA3．1质粒、OVA-pcDNA3．1质粒、pcDNA3．1质粒,皮下免疫Balb／c哮喘小鼠模型,40d后,观察肺组织的病理变化,并检测肺泡灌洗液中细胞总数及嗜酸粒细胞计数,细胞因子的含量以及血清中OVA特异的IgE抗体的水平。结果OVA-Fc-pcDNA3．1基因修饰的DNA疫苗免疫小鼠后,能有效抑制哮喘小鼠肺组织的炎细胞浸润,肺泡灌洗液中细胞总数明显下降（P〈0．05）,嗜酸性粒细胞的总数明显下降（P〈0．05）,肺泡灌洗液中IL-10、INF-Y的分泌增加（P〈0．05）,血清中OVA特异的IgE抗体能有效的得以控制（P〈0．05）。结论OVA-Fc-pcDNA3．1基因修饰的DNA疫苗可较OVA变应原基因更强的特异性地抑制哮喘小鼠的气道炎症,有望对哮喘的治疗具有重要的价值。     

The influence of CpG motifs on a protein or DNA-based Th2-type immune response against major pollen allergens Bet v 1a, Phl p 2 and Escherichia coli-derived beta-galactosidase

BACKGROUND: DNA immunization and protein immunization with CpG motifs as adjuvants represent promising approaches in allergen-specific immunotherapy. Objective: We investigated the effect of coinjection or prepriming with CpG-ODN on Th2-type responses induced by gene gun and protein immunization. METHODS: BALB/c mice were immunized with the gene gun using plasmid DNA containing the cDNAs coding for the genes of Bet v 1a, Phl p 2 and beta-galactosidase or with the purified Al(OH)(3)-adsorbed proteins. In addition, CpG-ODN were applied by coinjection or by prepriming treatment. Antibody and cytokine responses were measured by ELISA, proliferative and cytotoxic responses were determined by standard labeling procedures. Furthermore, the allergenic activity of sera was measured by passive cutaneous anaphylaxis. RESULTS: Gene gun immunization and protein immunization induced a clear Th2-type response for all antigens. The Th1-promoting effect of CpG-ODN coinjection together with gene gun immunization was restricted to beta-galactosidase as indicated by the increase of IgG2a and a marked expression of IFN-gamma. CpG motifs also increased the specific cytotoxic response against beta-galactosidase. Prepriming with CpG-ODN and gene gun or protein immunization with Bet v 1a exhibited no significant difference to the non-CpG control group. However, sera from mice preprimed with CpG-ODN induced no anaphylaxis with gene gun immunization, but with protein immunization. CONCLUSIONS: The effect of CpG motifs in vivo depends on a variety of parameters like the nature of the antigen and the immunization modality. Furthermore, our studies indicate that a combination of CpG + DNA immunization may be more effective in antagonizing Th2 responses than the combination of CpG + protein immunization.     

Oral administration of desloratadine prior to sensitization prevents allergen-induced airway inflammation and hyper-reactivity in mice

BACKGROUND: Histamine-1-receptor (H1R)-antagonists were shown to influence various immunological functions on different cell types and may thus be employed for immune-modulating strategies for the prevention of primary immune responses. OBJECTIVE: The aim of this study was to investigate the effects of an H1R-antagonist on allergen-induced sensitization, airway inflammation (AI) and airway hyper-reactivity (AHR) in a murine model. METHODS: BALB/c mice were systemically sensitized with ovalbumin (OVA) (six times, days 1-14) and challenged with aerosolized allergen (days 28-30). One day prior to the first and 2 h prior to every following sensitization, mice received either 1 or 0.01 microg of desloratadine (DL) or placebo per os. RESULTS: Sensitization with OVA significantly increased specific and total IgE and IgG1 serum levels, as well as in vitro IL-5 and IL-4 production by spleen and peribronchial lymph node (PBLN) cells. Sensitized and challenged mice showed a marked eosinophilic infiltration in broncho-alveolar lavage fluids and lung tissues, and developed in vivo AHR to inhaled methacholine. Oral treatment with DL prior to OVA sensitization significantly decreased production of OVA-specific IgG1, as well as in vitro Th2-cytokine production by spleen and PBLN cells, compared with OVA-sensitized mice. Moreover, eosinophilic inflammation and development of in vivo AHR were significantly reduced in DL-treated mice, compared with sensitized controls. CONCLUSION: Treatment with H1R-anatagonist prior to and during sensitization suppressed allergen-induced Th2 responses, as well as development of eosinophilic AI and AHR. This underscores an important immune modulating function of histamine, and implies a potential role of H1R-anatagonists in preventive strategies against allergic diseases.     

CpG oligodeoxinucleotides functions as an effective adjuvant in aged BALB/c mice

During aging, there is an increased rise in susceptibility to infectious diseases. However, it is still unresolved whether standard vaccine adjuvants are efficient in the elderly. We report that immunization with OVA plus synthetic oligodeoxinucleotides containing immunostimulatory CpG motifs (CpG-ODN) stimulates specific Th1 response in aged mice. The immunization with OVA/CpG-ODN induced an increase in CD19+ cells. These cells from aged mice in vivo captured OVA-FITC as efficiently as those from young mice. Interestingly, na?ve aged mice, which showed Th2 polarization and up-regulation of the expression of GATA-3, with immunization with OVA/CpG-ODN inducing Th1-specific response but maintaining a Th2 pattern in response to a non-specific stimulator of T cells. Our data suggest that the response elicited by CpG-ODN in aged mice have similar properties to the response developed in young mice, emphasizing the importance of the use of this adjuvant during aging.     

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.