Strain-dependent induction of allergic rhinitis without adjuvant in mice

Differential Activation of Splenic cDC1 and cDC2 Cell Subsets following Poxvirus Infection of BALB/c and C57BL/6 Mice

Conventional dendritic cells (cDCs) are innate immune cells that play a pivotal role in inducing antiviral adaptive immune responses due to their extraordinary ability to prime and polarize naïve T cells into different effector T helper (Th) subsets. The two major subpopulations of cDCs, cDC1 (CD8α+ in mice and CD141+ in human) and cDC2 (CD11b+ in mice and CD1c+ in human), can preferentially polarize T cells toward a Th1 and Th2 phenotype, respectively. During infection with ectromelia virus (ECTV), an orthopoxvirus from the Poxviridae family, the timing and activation of an appropriate Th immune response contributes to the resistance (Th1) or susceptibility (Th2) of inbred mouse strains to the lethal form of mousepox. Due to the high plasticity and diverse properties of cDC subpopulations in regulating the quality of a specific immune response, in the present study we compared the ability of splenic cDC1 and cDC2 originating from different ECTV-infected mouse strains to mature, activate, and polarize the Th immune response during mousepox. Our results demonstrated that during early stages of mousepox, both cDC subsets from resistant C57BL/6 and susceptible BALB/c mice were activated upon in vivo ECTV infection. These cells exhibited elevated levels of surface MHC class I and II, and co-stimulatory molecules and showed enhanced potential to produce cytokines. However, both cDC subsets from BALB/c mice displayed a higher maturation status than that of their counterparts from C57BL/6 mice. Despite their higher activation status, cDC1 and cDC2 from susceptible mice produced low amounts of Th1-polarizing cytokines, including IL-12 and IFN-γ, and the ability of these cells to stimulate the proliferation and Th1 polarization of allogeneic CD4+ T cells was severely compromised. In contrast, both cDC subsets from resistant mice produced significant amounts of Th1-polarizing cytokines and demonstrated greater capability in differentiating allogeneic T cells into Th1 cells compared to cDCs from BALB/c mice. Collectively, our results indicate that in the early stages of mousepox, splenic cDC subpopulations from the resistant mouse strain can better elicit a Th1 cell-mediated response than the susceptible strain can, probably contributing to the induction of the protective immune responses necessary for the control of virus dissemination and for survival from ECTV challenge.

A Preliminary Study in Immune Response of BALB/c and C57BL/6 Mice with a Locally Allergic Rhinitis Model

BACKGROUND

BALB/c and C57BL/6 mouse strains are commonly used in allergy research. The current study investigated the immunological differences between these two mouse strains with a locally allergic rhinitis model.

METHODS

Eighteen BALB/c and eighteen C57BL/6 mice received different doses of ovalbumin (OVA) intranasally for eight weeks (each mouse strain has three subgroups, 25 mg/mL group, 0.25 mg/mL group, and the PBS group). The allergic symptoms, OVA-specific serum antibody (IgE, IgG1, IgG2a), cytokines (IL-4, IFN-γ, IL-10) in the splenic culture supernatant, infiltrating eosinophils and goblet cells in local nasal mucosa were measured. RNA-seq technology was applied to detect differential gene expression in the local nasal mucosa.

RESULTS

With the same dose of OVA stimulation, the exacerbation of allergic symptoms was more pronounced in C57BL/6 than in BALB/c. BALB/c serum IgE, IgG1, and IgG2a gradually increased, and C57BL/6 produced fewer serum antibodies IgE and IgG1, while IgG2a never increased. BALB/c spleen cell culture supernatant IL-4 and IL-10 increased with increasing dose, and IFN-γ increased significantly in the intermediate dose group, while IL-4, IL-10, and IFN-γ did not increase in C57BL/6. The infiltration of eosinophils and goblet cells in both mice was proportional to the dose, while C57BL/6 was elevated more than BALB/c. RNA-seq suggested that the innate immune response, immune system process function, Jun kinase (JNK) pathway, and MAPKK pathway were upregulated in C57BL/6 compared to BALB/c. The core genes responsible for the differential immune response in both mice with allergic rhinitis were Kng2, Kng1, Gnb3, Lpar3, Lpar1, Pik3r1, Pf4, Apob, Rps9, and Fbxo2.

CONCLUSION

There are significant differences in the immunologic responses between BALB/c mice and C57BL/6 mice. BALB/c mice developed mild local allergic inflammatory reactions and strong systemic immune responses. In contrast, C57BL/6 mice had stronger local allergic inflammatory responses and relatively mild systemic immune responses. Different mice strains can be selected according to the research purpose.

Strain-Specific Differences in House Dust Mite (Dermatophagoides farinae)-Induced Mouse Models of Allergic Rhinitis

Objectives.

Limited information is available regarding strain-related differences in mouse models of allergic rhinitis induced by Dermatophagoides farinae (Der f1). In this study, we compared differences between two mouse strains and determined the optimal dose of Der f1 for allergic rhinitis mouse models.

Methods.

Forty-eight mice were assigned to the following six groups (n=8 per group): group A (control, BALB/c), group B (Der f1-sensitized BALB/c, 25 µg), group C (Der f1-sensitized BALB/c, 100 µg), group D (control, C57BL/6), group E (Der f1-sensitized C57BL/6, 25 µg), and group F (Der f1-sensitized C57BL/6, 100 µg). Allergic inflammation was induced with Der f1 and alum sensitization, followed by an intranasal challenge with Der f1. Rubbing and sneezing scores, eosinophil and neutrophil infiltration, and immunoglobulin, cytokine, and chemokine levels in the nasal mucosa and from splenocyte cultures were assessed.

Results.

Rubbing and sneezing scores were higher in groups B, C, E, and F than in groups A and D, with a similar pattern in both strains (i.e., group B vs. E and group C vs. F). Serum immunoglobulin levels were significantly elevated compared to the control in groups B and C, but not in groups E and F. Eosinophil and neutrophil infiltration increased (all P<0.05) after the Der f1 challenge (groups B, C, E, and F) compared to the control (groups A and D) in both the BALB/c and C57BL/6 strains, without any significant difference between the two strains (group A vs. D, group B vs. E, and group C vs. F) (P>0.05). BALB/c mice (group B) showed a greater elevation of splenic interleukin (IL)-4 (P<0.01), IL-5 (P<0.01), and IL-6 levels (P<0.05) and nasal IL-4 mRNA levels (P<0.001) than the C57BL/6 mice (group E). Interestingly, mice treated with 100 µg Der f1 showed a weaker allergic response than those treated with 25 µg.

Conclusion.

We found 25 µg to be a more appropriate dose for Der f1 sensitization. BALB/c mice are more biased toward a Th2 response and are a more suitable model for allergic rhinitis than C57BL/6 mice. This study provides information on the appropriate choice of a mouse model for allergic rhinitis.

Signals through CD40 Play a Critical Role in the Pathophysiology of Schistosoma Mansoni Egg Antigen–Induced Allergic Rhinitis in Mice

Background

Interaction between CD40 and CD40L is thought to regulate immune responses in several allergic diseases. However, little is known about its in vivo role in the pathophysiology of allergic rhinitis. We sought to determine whether the lack of signals through CD40 affects the pathophysiology of allergic rhinitis using a murine model.

Methods

Wild type (WT) and CD40-deficient BALB/c (CD40-/-) mice were sensitized intranasally to Schistosoma mansoni egg antigen (SEA). After repeated sensitization, histamine responsiveness, serum antibody titer including immunoglobulin E (IgE), nasal eosinophilia, and cytokine production by nasal mononuclear cells were determined in each group.

Results

Intranasal sensitization with SEA in WT mice elicited a strong Th2 response including SEA-specific IgE production, nasal eosinophilia, and interleukin (IL)-4, and IL-5 production by nasal mononuclear cells after antigen challenge. Production of SEA-specific IgE and IgG1 was abolished in SEA-sensitized CD40-/- mice. These mice showed impaired nasal eosinophilia and displayed markedly reduced histamine-induced nasal hyperresponsiveness as compared with WT mice. Furthermore, reduced production of IL-4 and IL-5 by nasal mononuclear cells was seen in CD40-/- mice.

Conclusion

These results show that signals through CD40 play a critical role in not only IgE production but also pathophysiology of allergic rhinitis such as nasal hyperresponsiveness and nasal eosinophilia.

Schistosome-Induced Fibrotic Disease: The Role of Hepatic Stellate Cells

Hepatic fibrosis is a common pathology in various liver diseases. Hepatic stellate cells (HSCs) are the main cell type responsible for collagen deposition and fibrosis formation in the liver. Schistosomiasis is characterised by granulomatous fibrosis around parasite eggs trapped within the liver and other host tissues. This response is facilitated by the recruitment of immune cells and the activation of HSCs. The interactions between HSCs and schistosome eggs are complex and diverse, and a better understanding of these interactions could lead to improved resolution of fibrotic liver disease, including that associated with schistosomiasis. Here, we discuss recent advances in HSC biology and the role of HSCs in hepatic schistosomiasis.

The 1st step initiation essential for allergen-specific IgE antibody production upon the 2nd step: Induction of non-specific IgE+ small B cells containing secondly-sensitized allergen-specific ones in mice firstly-sensitized with an allergen

There was a significant amount of non-specific, but not of allergen (e.g., papain, mite feces and four kinds of pollen)-specific, IgE antibodies (Abs) in the sera of normal mice. An i.n. injection of each allergen without adjuvant into mice caused an increase in total IgE Ab titers with a similar time course in the serum. However, the stage of initiation of allergy varied from allergen to allergen. Submandibular lymph node cells from normal mice contained papain-, but not mite feces- or pollen-specific IgE⁺ cells and an i.n. injection of papain induced papain-specific IgE Abs in the serum. In contrast, one (i.n.) or two (i.n. and s.c) injections of mite feces induced neither mite feces-specific IgE⁺ cells in the lymph nodes nor mite feces-specific IgE Abs in the serum. I.n. sensitization with cedar pollen induced cedar pollen-specific IgE⁺ small B cells in the lymph nodes on Day 10, when non-specific IgE Ab titers reached a peak in the serum, implying induction of related allergen-specific IgE⁺ small cells as well. In fact, a second (s.c.) injection of ragweed (or cedar) pollen into mice sensitized i.n. once with cedar (or ragweed) pollen, but not with mite feces, induced a large amount of ragweed (or cedar) pollen-specific IgE Abs in the serum. These results indicate that when firstly-sensitized non-specific IgE⁺ small B cells in mouse lymph nodes include some secondly-sensitized allergen-specific ones, mice produce IgE Abs specific for the secondly-injected allergen.

NKT cells contribute to basal IL-4 production but are not required to induce experimental asthma

CD1d-deficiency results in a selective deletion of NKT cells in mice that is reported to prevent murine allergic airway disease (AAD). Because we find 2–3 fold lower basal IL-4 production in CD1d^- mice than in wild-type (WT) mice, we hypothesized that the contribution made by NKT cells to AAD would depend on the strength of the stimulus used to induce the disease. Consequently, we compared CD1d-deficient mice to WT mice in the development of AAD, using several models of disease induction that differed in the type and dose of allergen, the site of sensitization and the duration of immunization. Surprisingly we found equivalent allergic inflammation and airway disease in WT and CD1d^- mice in all models investigated. Consistent with this, NKT cells constituted only ~2% of CD4⁺ T cells in the lungs of mice with AAD, and IL-4-transcribing NKT cells did not expand with disease induction. Concerned that the congenital absence of NKT cells might have caused a compensatory shift within the immune response, we administered an anti-CD1d monoclonal Ab (mAb) to block NKT function before airway treatments, before or after systemic sensitization to antigen. Such Ab treatment did not affect disease severity. We suggest that the differences reported in the literature regarding the significance of NKT cells in the induction of allergic airway disease may have less to do with the methods used to study the disease and more to do with the animals themselves and/or the facilities used to house them.

Immunosuppressive effect of sinomenine in an allergic rhinitis mouse model

Allergic rhinitis (AR) is a chronic allergic airway disease that has become a significant global public health issue. Sinomenine (SN), a natural phytochemical found in Sinomenium acutum, showed anti-inflammatory and immunosuppressive effect in previous studies. In order to explore the role of SN in the treatment of AR, mice were sensitized and challenged by ovalbumin (OVA) to establish an AR mouse model. SN was administered to AR mice orally, and compared with dexamethasone treatment as a positive control. Nasal symptoms and histopathological changes were used to evaluate the effect of SN treatment in the AR mice model. In addition, the levels of anti-OVA specific IgE and various cytokines in the serum were measured by enzyme-linked immunosorbent assay, while the levels of transforming growth factor-β (TGF-β) in the mucosa were also detected by western blot analysis and reverse transcription-quantitative polymerase chain reaction. AR mice that received SN treatment had reduced symptom scores and milder eosinophil infiltration. The serum levels of anti-OVA specific IgE and interleukin-4 significantly decreased following SN treatment. Furthermore, TGF-β expression levels in the serum and nasal mucosa tissue in AR mice increased when compared with those in AR mice without treatment. In conclusion, SN treatment alleviated the symptoms of AR in mice and had an immunosuppressive effect on AR, which may result from the upregulation of TGF-β.

Establishment of a new animal model of allergic rhinitis with biphasic sneezing by intranasal sensitization with Staphylococcal enterotoxin B

Allergic rhinitis (AR) is a global health problem. The effectiveness of currently available medications is limited and therefore investigation for more effective drugs is essential. The aim of the present study was to establish a model of AR in guinea pigs that can be utilized for the further investigation of new drugs. Guinea pigs were intranasally sensitized with 1 µg Staphylococcal enterotoxin B (SEB) dissolved in 40 µl saline once daily for 14 days. One week after the last sensitization, the same treatment was applied intranasally once every four days for a total of 30 times. In the treatment group, terfenadine was administered orally 70 min before the 4th, 14th and 24th challenge. Sneezing and nasal scratching were evaluated following each of the 30 challenges. The quantity of antigen-specific antibodies in the serum was measured. Between the 19th and 30th challenges, the guinea pigs in the model group produced significant biphasic elevations in sneezing number, with peaks 10 min-2 h and 4-8 h after the SEB challenges. In addition, the guinea pigs produced significantly more sneezing in the first peak during the 19th to 30th challenges than during the first to 18th challenges (P<0.01). Terfenadine significantly inhibited the early- and late-phase sneezing at all challenge times. The serum levels of SEB-specific immunoglobulin (Ig) E and IgG₁ were higher in the model group in comparison with those in the control group (P<0.01). This experiment demonstrated that SEB can induce typical AR with biphasic sneezing in guinea pigs. Histamine may play an important role in the early- and the late-phase sneezing in the model of AR. This model can be potentially used for the investigation of new drugs.

Innate Mucosal Immune System Response of BALB/c vs C57BL/6 Mice to Injury in the Setting of Enteral and Parenteral Feeding

BACKGROUND

Outbred mice exhibit increased airway and intestinal immunoglobulin A (IgA) following injury when fed normal chow, consistent with humans. Parenteral nutrition (PN) eliminates IgA increases at both sites. Inbred mice are needed for detailed immunological studies; however, specific strains have not been evaluated for this purpose. BALB/c and C57BL/6 are common inbred mouse strains but demonstrate divergent immune responses to analogous stress. This study addressed which inbred mouse strain best replicates the outbred mouse and human immune response to injury.

METHODS

Intravenously cannulated mice received chow or PN for 5 days and then underwent sacrifice at 0 or 8 hours following controlled surgical injury (BALB/c: n = 16-21/group; C57BL/6: n = 12-15/group). Bronchoalveolar lavage (BAL) was analyzed by enzyme-linked immunosorbent assay for IgA, tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6, while small intestinal wash fluid (SIWF) was analyzed for IgA.

RESULTS

No significant increase in BAL IgA occurred following injury in chow- or PN-fed BALB/c mice (chow: P = .1; PN: P = .7) despite significant increases in BAL TNF-α and SIWF IgA (chow: 264 ± 28 vs 548 ± 37, P < .0001; PN: 150 ± 12 vs 301 ± 17, P < .0001). Injury significantly increased mucosal IgA in chow-fed C57BL/6 mice (BAL: 149 ± 33 vs 342 ± 87, P = .01; SIWF: 236 ± 28 vs 335 ± 32, P = .006) and BAL cytokines. After injury, PN-fed C57BL/6 mice exhibited no difference in BAL IgA (P = .9), BAL cytokines, or SIWF IgA (P = .1).

CONCLUSIONS

C57BL/6 mice exhibit similar airway responses to injury as outbred mice and humans, providing an appropriate model for studying mucosal responses to injury. The BALB/c mucosal immune system responds differently to injury and does not replicate the human injury response.

Repeated antigen painting and sublingual immunotherapy in mice convert sublingual dendritic cell subsets

The sublingual mucosa (SLM) is utilized as the site for sublingual immunotherapy (SLIT) to induce tolerance against allergens. The contribution of SLM-dendritic cells (SLM-DCs) has not been clarified. The aim of this study was to examine the dynamics and phenotype of SLM-DCs after topical antigen painting and SLIT. SLM-DCs were histologically evaluated after FITC painting. A novel murine Japanese cedar pollinosis (JCP) model was generated and change in SLM-DCs after SLIT was examined. The density of SLM-DCs was clearly lower compared with the buccal mucosa and dorsal surface of the tongue. Topical FITC painting on the SLM induced maximal recruitment of submucosal DCs (smDCs) at 6h, but most smDCs had vanished at 24h. Repeated painting on the SLM induced exhaustion and conversion of the smDC phenotype. CD206(high)CD11c(low) round-type cells with fewer dendrites and less lymph node migration capacity became dominant. In the murine model of JCP, SLIT efficiently inhibited clinical symptoms and allergen-mediated immunological responses. SLIT markedly reduced the number of SLM-DCs, converted to the round-type dominant phenotype and inhibited the activation of regional lymph node DCs. Topical antigen painting on the SLM induced rapid exhaustion and conversion of smDCs. The unique dynamics of SLM-DCs may contribute to tolerance induction in SLIT.

Taenia crassiceps infection and its excreted/secreted products inhibit STAT1 activation in response to IFN-γ

It is well understood that helminth infections modulate the immune responses of their hosts but the mechanisms involved in this modulation are not fully known. Macrophages and dendritic cells appear to be consistently affected during this type of infection and are common target cells for helminth-derived molecules. In this report, we show that macrophages obtained from chronically Taenia crassiceps-infected mice displayed an impaired response to recombinant murine IFN-γ, but not to recombinant murine IL-4, as measured based on the phosphorylation of STAT1 and STAT6, respectively. These macrophages expressed high levels of SOCS3. However, the inhibition of phosphatase activity by orthovanadate restored the IFN-γ response of these macrophages by increasing STAT1 phosphorylation without affecting SOCS3 expression. Therefore, we aimed to identify the phosphatases associated with IFN-γ signaling inhibition and found that macrophages from T. crassiceps-infected mice displayed enhanced SHP-1 expression. Interestingly, the exposure of naïve macrophages to T. crassiceps excreted/secreted products similarly interfered with IFN-γ-induced STAT1 phosphorylation. Moreover, macrophages exposed to T. crassiceps excreted/secreted products expressed high levels of SOCS3 as well as SHP-1. Strikingly, human peripheral blood mononuclear cells that were exposed to T. crassiceps excreted/secreted products in vitro also displayed impaired STAT1 phosphorylation in response to IFN-γ; again, phosphatase inhibition abrogated the T. crassiceps excreted/secreted product-altered IFN-γ signaling. These data demonstrate a new mechanism by which helminth infection and the products derived during this infection target intracellular pathways to block the response to inflammatory cytokines such as IFN-γ in both murine and human cells.

IgE Production after Four Routes of Injections of Japanese Cedar Pollen Allergen without Adjuvant: Crucial Role of Resident Cells at Intraperitoneal or Intranasal Injection Site in the Production of Specific IgE toward the Allergen

The production of specific IgE antibodies directed toward cedar pollen correlates well with the onset of allergic rhinitis; but the mechanisms of allergen recognition as nonself and Ig class switch to IgE by the immune system are still not fully understood. In the present study, we injected cedar pollen into mice through 4 different routes (intranasal (i.n.), intraperitoneal (i.p.), intravenous (i.v.), and subcutaneous (s.c.)) without adjuvant 1 to 3 times, and determined time-dependent changes in the total and specific serum IgE levels compared with those in the serum levels of other isotype Igs. After an i.p. or i.n. injection of allergen into the mice, they produced a 1.5-to 1.7-fold increase in total IgE, but none in IgG, IgM, or IgA antibodies in their serum, whereas an i.v. or s.c. injection of allergen was inactive as an inducer of total IgE antibodies. Upon a 2nd (s.c.) injection of the allergen into the i.p. or i.n. sensitized mice, a large amount of allergen-specific IgE antibodies was found in the serum. In the case of i.v. or s.c. sensitized mice, however, they produced total, but not specific, IgE antibodies; and a 3rd (s.c.) injection of the allergen resulted in a large amount of specific IgE antibodies in the serum. These results imply that resident cells at the i.p. or i.n. injection site may play a crucial role in the efficient production of total and specific IgE antibodies toward the allergen.

Induction of allergic rhinitis in mice

We describe a method for allergic rhinitis (AR) induction in mice. Methodology involves nasal infusions of small volumes of ovalbumin for both initial sensitization and challenges. The latter are frequent and carried out over several weeks. This methodology more closely resembles natural AR induction than does the common use of systemic sensitization, often with adjuvants, followed by nasal challenges with relatively large allergen volumes. Also described are methodologies for collection of cardiac blood and perfusion for preparation of histological samples, both essential in verifying AR induction in individual animals.

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

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

Tissue-specific effects of allergic rhinitis in mouse nasal epithelia

Allergic rhinitis (AR) can cause significant olfactory loss, but few studies have specifically investigated AR effects on olfactory and nasal respiratory tissues per se. To address this, we used a murine AR protocol employing nasal allergen infusion for both sensitization and challenges. Seven- to 11-week BALB/c mice were bilaterally infused with 1% ovalbumin (OVA) in phosphate-buffered saline (PBS) or PBS alone for 6 or 11 weeks, given single bilateral PBS or OVA infusions 24 h before sacrifice, or left untreated. High OVA-specific IgE serum levels and eosinophil infiltration confirmed AR induction. Olfactory (OE) and respiratory (RE) epithelia showed distinctly different responses, most conspicuously, massive eosinophil infiltration of immediately RE-subjacent lamina propria. In OE, such infiltration was minimal. Significant RE hypertrophy and hyperplasia also occurred, although OE organization was generally maintained and extensive disruption localized despite a 20% reduction in sensory neurons and globose basal cells after 11 weeks OVA. Pronounced Bowman's gland hypertrophy crowded both OE and olfactory nerve bundles. Cellular proliferation was widely distributed in RE but in OE was localized to normally thinner OE and RE-proximal OE, suggesting possible indirect RE influences. Terminal deoxynucleotide transferase (TdT) nick end labeling was greater in OE than RE and, in contrast to other effects, occurred with acute infusions and chronic PBS alone, often unilaterally. Following chronic OVA, AR-related bilateral increases appeared superimposed on those. These findings indicate AR effects on olfactory function may be complex, reflecting various levels of RE/OE responses and interactions.

Modulation of specific and allergy-related immune responses by helminths

Helminths are master regulators of host immune responses utilising complex mechanisms to dampen host protective Th2-type responses and favour long-term persistence. Such evasion mechanisms ensure mutual survival of both the parasite and the host. In this paper, we present recent findings on the cells that are targeted by helminths and the molecules and mechanisms that are induced during infection. We discuss the impact of these factors on the host response as well as their effect in preventing the development of aberrant allergic inflammation. We also examine recent findings on helminth-derived molecules that can be used as tools to pinpoint the underlying mechanisms of immune regulation or to determine new anti-inflammatory therapeutics.

Adipose tissue-derived stem cells for cell therapy of airway allergic diseases in mouse

The purpose of this study was to compare murine mesenchymal stem cells (MSCs) isolated from bone marrow (BM) and adipose tissue (AT) for the selection of suitable MSCs in cell therapy of an airway allergic animal model. We compared MSCs of BALB/c mice derived from BM and AT with respect to proliferation potential, immunophenotype, and multilineage differentiation capacity. In proliferation potential, MSCs from AT (ASCs) showed higher fibroblastoid colony-forming units frequencies and colony-forming efficiency than MSCs from BM (BMSCs). The flow cytometry analysis showed that both ASCs and BMSCs expressed MSCs-related antigens (CD90 and CD105), whereas they did not express hematopoiesis-related antigens (CD45 and CD11b). There was no significant difference in adipogenic, osteogenic, and chondrogenic differentiation between the murine ASCs and BMSCs. In conclusion, the present study has shown that ASCs had higher CFU-F frequencies and colony-forming efficiency than BMSCs. ASCs and BMSCs presented a similar surface immunophenotype and multilineage differentiation capacity. Therefore, ASCs in BALB/c mice might be a more useful material for cell therapy of the airway allergic experiment due to the abundance, relatively easy harvesting and high proliferation potential.

Murine models of airway fungal exposure and allergic sensitization

Inhalation of common indoor filamentous fungi has been associated with the induction or exacerbation of allergic respiratory disease. The understanding of fungal inhalation and allergic sensitization has significantly advanced with the use of small animal models, especially mouse models. Numerous studies have employed different animal exposure and sensitization techniques, each with inherent advantages and disadvantages that are addressed in this review. In addition, most studies involve exposure of animals to fungal spores or spore extracts while neglecting the influence of hyphal or subcellular fragment exposures. Recent literature examining the potential for hyphae and fungal fragments to induce or exacerbate allergy is discussed. Innate immune recognition of fungal elements and their contribution to lung allergic inflammation in animal models are also reviewed. Though physical properties of fungi play an important role following exposure, host immune development is also critical in airway inflammation and allergy. We discuss the importance of environmental factors that influence early immune development and subsequent susceptibility to allergy. Murine studies that examine the role of intestinal microflora and prenatal or early life environmental factors that promote allergic sensitization are also evaluated. Future studies will require animal models that accurately reflect natural fungal exposures and identify environmental factors that influence immune development and thus promote respiratory fungal allergy and disease.

CRTH2 plays an essential role in the pathophysiology of Cry j 1-induced pollinosis in mice

PGD(2) is the major prostanoid produced during the acute phase of allergic reactions. Two PGD(2) receptors have been isolated, DP and CRTH2 (chemoattractant receptor-homologous molecule expressed on Th2 cells), but whether they participate in the pathophysiology of allergic diseases remains unclear. We investigated the role of CRTH2 in the initiation of allergic rhinitis in mice. First, we developed a novel murine model of pollinosis, a type of seasonal allergic rhinitis. Additionally, pathophysiological differences in the pollinosis were compared between wild-type and CRTH2 gene-deficient mice. An effect of treatment with ramatroban, a CRTH2/T-prostanoid receptor dual antagonist, was also determined. Repeated intranasal sensitization with Cry j 1, the major allergen of Cryptomeria japonica pollen, in the absence of adjuvants significantly exacerbated nasal hyperresponsive symptoms, Cry j 1-specific IgE and IgG1 production, nasal eosinophilia, and Cry j 1-induced in vitro production of IL-4 and IL-5 by submandibular lymph node cells. Additionally, CRTH2 mRNA in nasal mucosa was significantly elevated in Cry j 1-sensitized mice. Following repeated intranasal sensitization with Cry j 1, CRTH2 gene-deficient mice had significantly weaker Cry j 1-specific IgE/IgG1 production, nasal eosinophilia, and IL-4 production by submandibular lymph node cells than did wild-type mice. Similar results were found in mice treated with ramatroban. These results suggest that the PGD(2)-CRTH2 interaction is elevated following sensitization and plays a proinflammatory role in the pathophysiology of allergic rhinitis, especially pollinosis in mice.

STAT1 is involved in the pathogenesis of murine allergic rhinitis

BACKGROUND

Signal transducer and activator of transcription (STAT) 1 signaling pathway mediates biological functions of interferon (IFN) gamma, which is a key cytokine-regulating T helper 1 (Thl) differentiation. Although constitutive activation of STAT1 has been reported in the airway epithelium of patients with chronic asthma, its in vivo role in the pathogenesis of allergic rhinitis is not clear. We determined the role of STAT1 in the pathogenesis of allergic rhinitis in vivo using STAT1 gene-deficient (STAT1-/-) mice and a murine model of Schistosoma mansoni egg antigen (SEA)-induced allergic rhinitis.

METHODS

STATI -/- BALB/c and wild-type (WT) mice were sensitized by intranasal administration of SEA, and their immunologic responses were examined.

RESULTS

STATI-1- mice showed impaired nasal eosinophilia and markedly reduced histamine-induced nasal hyperresponsiveness after SEA sensitization. Moreover, levels of Th2-associated SEA-specific IgG1 and IgE antibodies were lower in STAT1-/- mice. Anti-CD3stimulated nasal lymphocytes from STAT1-/-mice also produced less amounts of Th2-associated cytokines IL-4, IL-5, IL-10, and IL-13 compared with WT mice, but both produced comparable levels of IFN-gamma.

CONCLUSION

These results show that STAT1 is involved in the pathogenesis of SEA-induced allergic rhinitis in BALB/c mice. Furthermore, they reveal a surprising role of STAT1 in induction of nasal eosinophilia, and Th2-type cytokine production from nasal lymphocytes during allergic rhinitis.

Construction and delivery of gene therapy vector containing soluble TNFalpha receptor-IgGFc fusion gene for the treatment of allergic rhinitis

Tumor necrosis factor alpha plays primary role in the pathogenesis of inflammatory diseases. TNFalpha is essential for antigen-specific IgE production and for the induction of Th2-type cytokines. The lack of TNFalpha inhibited the development of allergic rhinitis. In this study, the chimeric gene of soluble TNF receptor and IgGFc fragment (sTNFR-IgGFc) was cloned into the EBV-based plasmid pGEG. When the plasmid pGEG.sTNFR-IgGFc was transferred to endothelium cell, a considerable expression of the sTNFR-IgGFc fusion protein was detected. Moreover, the expression product in the supernatant could antagonize the cytolytic activity of TNFalpha on L929 cells. Then the plasmid was delivered into nasal mucosa of allergic rhinitis mice to determine its effect on this animal model. Results showed that symptoms in treated group were improved. Pathological examination showed the numbers of eosinophil, mast cell and IL-5(+) cells in treated groups were reduced compared with placebo group. These data showed that pGEG.sTNFR-IgGFc expression plasmid is potential for the treatment of allergic rhinitis, and suggest that the antagonist of TNFalpha may provide a new approach for the treatment of 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.

Genetically modified plants and food hypersensitivity diseases: usage and implications of experimental models for risk assessment

The recent advances in biotechnology in the plant industry have led to increasing crop production and yield that in turn has increased the usage of genetically modified (GM) food in the human food chain. The usage of GM foods for human consumption has raised a number of fundamental questions including the ability of GM foods to elicit potentially harmful immunological responses, including allergic hypersensitivity. To assess the safety of foods derived from GM plants including allergenic potential, the US FDA, Food and Agriculture Organization of the United Nations (FAO)/World Health Organization (WHO), and the EU have developed approaches for evaluation assessment. One assessment approach that has been a very active area of research and debate is the development and usage of animal models to assess the potential allergenicity of GM foods. A number of specific animal models employing rodents, pigs, and dogs have been developed for allergenicity assessment. However, validation of these models is needed and consideration of the criteria for an appropriate animal model for the assessment of allergenicity in GM plants is required. We have recently employed a BALB/c mouse model to assess the potential allergenicity of GM plants. We have been able to demonstrate that this model is able to detect differences in antigenicity and identify aspects of protein post-translational modifications that can alter antigenicity. Furthermore, this model has also enabled us to examine the usage of GM plants as a therapeutic approach for the treatment of allergic diseases. This review discusses the current approaches to assess the allergenic potential of GM food and particularly focusing on the usage of animal models to determine the potential allergenicity of GM foods and gives an overview of our recent findings and implications of these studies.

Listeriolysin O, a cytolysin derived from Listeria monocytogenes, inhibits generation of ovalbumin-specific Th2 immune response by skewing maturation of antigen-specific T cells into Th1 cells

Listeriolysin O (LLO), a cholesterol-dependent cytolysin derived from Listeria monocytogenes, is a potent inducer of interleukin (IL)-12, IL-18 and interferon (IFN)-gamma. We have shown that LLO facilitates development of T cells mediating protective immunity against L. monocytogenes through the induction of IFN-gamma production at an early stage. Based on this finding, it is postulated that LLO inhibits differentiation of Th2 cells and the Th2 immune response. By using a murine model of ovalbumin (OVA)-induced allergic rhinitis, we investigated whether LLO has an ability to modulate the Th2-type immune disorder. In mice sensitized intraperitoneally with ovalbumin (OVA)/alum and challenged intranasally with OVA, a large number of eosinophils migrated into the nasal tissue, and high titres of anti-OVA IgE and IgG(1) antibodies were detected in sera. However, LLO treatment during sensitization markedly inhibited the eosinophil infiltration and production of these anti-OVA antibodies. A large number of T cells from mice sensitized and challenged with OVA produced high level of IL-4 and IL-5 but not IFN-gamma after stimulation with OVA. In contrast, OVA-specific IFN-gamma-producing T cells were preferentially induced in mice treated with LLO at the time of sensitization. In the absence of LLO administration, the expression level of GATA-3 and SOCS-3 in CD4(+) T cells was enhanced after sensitization with OVA. LLO treatment resulted in a reduction of GATA-3 and SOCS-3 expressions but induced the transcription of T-bet instead. Taken together, these data show clearly that LLO is capable of inhibiting Th2 immune response by skewing differentiation of antigen-specific T cells into Th1 cells.

Purification and structural analysis of the novel glycoprotein allergen Cyn d 24, a pathogenesis-related protein PR-1, from Bermuda grass pollen

Bermuda grass pollen (BGP) contains a very complex mixture of allergens, but only a few have been characterized. One of the allergens, with an apparent molecular mass of 21 kDa, has been shown to bind serum IgE from 29% of patients with BGP allergy. A combination of chromatographic techniques (ion exchange and reverse phase HPLC) was used to purify the 21 kDa allergen. Immunoblotting was performed to investigate its IgE binding and lectin-binding activities, and the Lysyl-C endopeptidase digested peptides were determined by N-terminal sequencing. The cDNA sequence was analyzed by RACE PCR-based cloning. The protein mass and the putative glycan structure were further elucidated using MALDI-TOF mass spectrometry. The purified 21 kDa allergen was designated Cyn d 24 according to the protocol of International Union of Immunological Societies (IUIS). It has a molecular mass of 18,411 Da by MALDI-TOF analysis and a pI of 5.9. The cDNA encoding Cyn d 24 was predicted to produce a 153 amino acid mature protein containing tow conserved sequences seen in the pathogen-related protein family. Carbohydrate analysis showed that the most abundant N-linked glycan is a alpha(3)-fucosylated pauci-mannose (Man3GlcNAc2) structure, without a Xyl beta-(1,2)-linked to the branching beta-Man. Thus, Cyn d 24 is a glycoprotein and the results of the sequence alignment indicate that this novel allergen is a pathogenesis-related protein 1. To the best of our knowledge, this is the first study to identify any grass pollen allergen as a pathogenesis-related protein 1.

The allergy adjuvant effect of particles - genetic factors influence antibody and cytokine responses

BACKGROUND

There is increasing epidemiological and experimental evidence for an aggravating effect of particulate air pollution on asthma and allergic symptoms and, to a lesser extent, on allergic sensitization. Genetic factors appear to influence not only the magnitude, but also the quality of the adjuvant effect of particles with respect to allergen-specific IgE (Th2-associated) and IgG2a (Th1-associated) responses. In the present study, we aimed to investigate how the genetic background influences the responses to the allergen and particles alone and in combination. We examined how polystyrene particles (PSP) affected the IgE and IgG2a responses against the model allergen ovalbumin (OVA), after subcutaneous injection into the footpad of BALB/cA, BALB/cJ, NIH and C3H/HeN mice, Further, ex vivo IL-4, IFN-gamma and IL-10 cytokine secretion by Con A-stimulated cells from the draining popliteal lymph node (PLN) five days after injection of OVA and PSP separately or in combination was determined.

RESULTS

PSP injected with OVA increased the levels of OVA-specific IgE antibodies in all strains examined. In contrast, the IgG2a levels were significantly increased only in NIH and C3H/HeN mice. PSP in the presence of OVA increased cell numbers and IL-4, IL-10 and IFN-gamma levels in BALB/cA, NIH and C3H/HeN mice, with the exception of IFN-gamma in NIH mice. However, each mouse strain had their unique pattern of response to OVA+PSP, OVA and PSP, and also their unique background cytokine response (i.e. the cytokine response in cells from mice injected with buffer only).

CONCLUSION

Genetic factors (i.e. the strain of mice) influenced the susceptibility to the adjuvant effect of PSP on both secondary antibody responses and primary cellular responses in the lymph node, as well as the cellular responses to both OVA and PSP given separately. Interestingly, PSP alone induced cytokine responses in the lymph node in some of the mouse strains. Furthermore, we found that the ex vivo cytokine patterns did not predict the in vivo Th2- and Th1-associated antibody response patterns in the different mouse strains. The results indicate that insoluble particles act by increasing the inherent response to the allergen, and that the genetic background may determine whether an additional Th1-associated component is added to the response.

Nasal exposure to Staphylococcal enterotoxin enhances the development of allergic rhinitis in mice

BACKGROUND

Staphylococcal enterotoxins (SEs) appear to play a role in the pathogenesis of allergic disease. However, little is known whether the nasal exposure to SE affects the development of allergic rhinitis (AR).

OBJECTIVE

We sought to determine the in vivo effect of nasal exposure to SE on the development of AR using mouse model.

METHODS

BALB/c mice were intranasally sensitized with Schistosoma mansoni egg antigen (SmEA) in the presence or absence of staphylococcal enterotoxin B (SEB). Control mice were intranasally sensitized with either SEB or SmEA alone. The production of antigen-specific antibodies including IgE, nasal eosinoplilia and cytokines by nasal mononuclear cells was compared among mice that had or had not received SEB treatment.

RESULTS

Nasal exposure to SEB enhanced the development of AR in SmEA-sensitized mice, as manifested by SmEA-specific IgE production, nasal eosinophilia, and IL-4 and IL-5 production by nasal mononuclear cells after Ag challenge. This treatment also elicited IFN-gamma production by SmEA-primed cells. In addition, these mice produced SEB-specific IgE whereas mice treated with SEB without SmEA sensitization did not produce SEB-specific IgE or demonstrate nasal eosinophilia.

CONCLUSION

These results suggest that the nasal exposure to SEB enhances susceptibility to AR although the exposure to SE solely does not induce AR.

Mouse strain specificity of the IgE response to the major allergens of Phleum pratense

BACKGROUND

IgE immune responses against major allergens from Phleum pratense in low- and high-responder mouse strains were compared and the influence of alum was assessed, in order to evaluate the effect of the genetic background and adjuvants on IgE reactivity in a mouse model for P. pratense allergy.

METHODS

Different mouse strains and F1 offspring were sensitized with P. pratense pollen extract. Serum IgE levels, the induction of specific IgE antibodies and immediate cutaneous hypersensitivity reactions were monitored by ELISA, Western blot and a skin test, respectively.

RESULTS

All mouse strains investigated mounted an IgE response and exhibited a positive skin test to pollen extract. Differences were seen in the level of total serum IgE and in specific IgE reactivity to different major allergens of P. pratense. Notable differences were seen in IgE reactivity and immediate hypersensitivity against Phl p 1, which were only observed in SJL/j mice. The foremost influence of alum was on total IgE production levels.

CONCLUSIONS

Alum is not necessary as an adjuvant to elicit IgE reactivity against the clinically relevant allergens of P. pratense, since even low-responder mouse strains mounted a hypersensitivity reaction after sensitization without the adjuvant using otherwise identical sensitization strategies. Moreover, when analyzing the allergenicity of a compound, the hypersensitivity response of different mouse strains should be considered, as implicated by the differential results obtained for IgE reactivity against Phl p 1. Lastly, a genetic component may be involved in IgE reactivity to Phl p 1.

Roles of major oligosaccharides on Cry j 1 in human immunoglobulin E and T cell responses

BACKGROUND

We have demonstrated that carbohydrates in Cry j 1, the major allergen of Cryptomeria japonica pollen, play a major role in promoting Cry j 1-specific Th2 response. However, little is known as to whether the carbohydrates directly participate in allergic responses.

OBJECTIVE

We sought to determine whether Cry j 1-related oligosaccharides function as IgE and/or T cell epitopes. In addition, the regulatory effect of Cry j 1-related oligosaccharide on Cry j 1-specific T cell responses was investigated.

METHODS

Two monovalent oligosaccharides largely found on Cry j 1, Manalpha1-6(Manalpha1-3)(Xylbeta1-2)Manbeta1-4GlcNAcbeta1-4(Fucalpha1-3)GlcNAc (M3FX), and GlcNAcbeta1-2Manalpha1-6(GlcNAcbeta1-2Manalpha1-3)(Xylbeta1-2)Manbeta1-4GlcNAcbeta1-4(Fucalpha1-3)GlcNAc (GN2M3FX) were prepared. Manalpha1-2Manalpha1-6(Manalpha1-2Manalpha1-3)Manalpha1-6(Manalpha1-2Manalpha1-2Manalpha1-3)Manbeta1-4GlcNAcbeta1-4GlcNAc (M9A) was used as control. Competitive inhibition ELISA for Cry j 1-specific IgE was performed using these oligosaccharides as inhibitors. In addition, T cell lines specific for Cry j 1 or purified protein derivative of Mycobacterium tubecurosis (PPD) were established, and cellular responses against these oligosaccharides were investigated in the presence or absence of the respective antigens.

RESULTS

Overall, neither M3FX nor GN2M3FX displayed inhibitory effect on the binding between IgE and Cry j 1. In addition, M3FX did not by itself stimulate Cry j 1 or PPD-specific T cells. However, M3FX significantly inhibited Cry j 1-induced proliferation and IL-4 production in Cry j 1-specific T cells. Such an inhibitory effect was not seen in PPD-specific T cell responses.

CONCLUSION

These results suggest that Cry j 1-related oligosaccharides are not major epitopes for IgE or T cells. However, these oligosaccharides have a novel potential to inhibit Cry j 1-specific T cell responses selectively.

Roles of FcgammaRIIB in nasal eosinophilia and IgE production in murine allergic rhinitis

The low-affinity IgG Fc receptor, FcgammaRIIB, displays inhibitory potential in experimental models such as autoimmune diseases. However, whether this receptor is involved in the onset of allergic diseases remains unknown. This study examines the role of FcgammaRIIB in the initiation of allergic rhinitis in mice. Repeated intranasal sensitization with Schistosoma mansoni egg antigen (SEA) induced SEA-specific IgE and marked nasal eosinophilia in high-responder BALB/c mice. FcgammaRIIB gene-deficient (-/-) BALB/c mice displayed severe eosinophilia compared with that of wild-type counterparts. However, FcgammaRIIB -/- mice conversely produced less SEA-specific IgE. The production of interleukin (IL)-4 but not of IL-5 or IFN-gamma by nasal mononuclear cells was also decreased in FcgammaRIIB -/- mice, suggesting that the exacerbation of nasal eosinophila in FcgammaRIIB -/- mice is independent of the local IL-5 levels. The findings in low responder C57BL/6 mice were similar. In addition, nasal eosinophilia in FcgammaRIIB -/- mice passively sensitized with SEA was exacerbated, and conversely, specific IgE production was inhibited after a nasal challenge. These results suggest that FcgammaRIIB plays a regulatory role in the initiation of allergic rhinitis that is independent of either mouse strain or type of sensitization.

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.

Immune responses in the lung and local lymph node of A/J mice to intranasal sensitization and challenge with adjuvant-free ovalbumin

Pathologic features of IgE-mediated allergic airway diseases include airway infiltration of inflammatory cells (eg, lymphocytes, plasma cells, and eosinophils) and mucous cell metaplasia (MCM) in airway epithelium. CD4(+) T lymphocytes, specifically those producing a type 2 (Th2) cytokine profile, are necessary for the induction of IgE-mediated allergic airway responses. Most experimental models of IgE-mediated allergic airway disease use systemic (eg, intraperitoneal) administration of an allergen coupled with an adjuvant to sensitize animals. Cytokine changes are measured in a number of ways including in bronchoalveolar lavage fluid (BALF) or lymph node cells stimulated ex vivo. The primary objective of this study was to test the hypothesis that intranasal sensitization and challenge of mice with ovalbumin in the absence of an adjuvant will induce the pathologic features that are characteristic of IgE-mediated allergic airway disease. Another objective was to determine if intranasal delivery of this allergen will result in the induction of a profile of cytokine gene expression in the lung and tracheobronchial (TB) lymph node, that is typical of immunologic changes associated with IgE-mediated allergic airway disease. Only mice that were intranasally sensitized and challenged with ovalbumin exhibited pulmonary lesions that included marked MCM in the respiratory epithelium lining the nasal and pulmonary airways, and an associated mixed inflammatory cell influx consisting of lymphocytes, plasma cells and eosinophils. Ovalbumin-treated mice also exhibited enhanced expression of the Th2 cytokine mRNAs IL-4, IL-5, IL-10, and IL-13 in the lung and IL-4 in the TB lymph node, and concurrent increases in ovalbumin-specific IgE in the serum. The results of this study indicate that A/J mice intranasally instilled with ovalbumin without adjuvant have the hallmark histopathologic and immunologic features of IgE-mediated allergic airway disease of humans.

Molecular characterization of an interleukin-4-inducing factor from Schistosoma mansoni eggs

The eggs of the parasitic trematode Schistosoma mansoni are powerful inducers of a T helper type 2 (Th2) immune response and immunoglobulin E (IgE) production. S. mansoni egg extract (SmEA) stimulates human basophils to rapidly release large amounts of interleukin (IL)-4, the key promoter of a Th2 response. Here we show purification and sequence of the IL-4-inducing principle of S. mansoni eggs (IPSE). Stimulation studies with human basophils using SmEA fractions and natural and recombinant IPSE as well as neutralization and immunodepletion studies using antibodies to recombinant IPSE demonstrate that IPSE is the bioactive principle in SmEA leading to activation of basophils and to expression of IL-4 and IL-13. Regarding the mechanism of action, blot analysis showed that IPSE is an IgE-binding factor, suggesting that it becomes effective via cross-linking receptor-bound IgE on basophils. Immunohistology revealed that IPSE is enriched in and secreted from the subshell area of the schistosome egg. We conclude from these data that IPSE may be an important parasite-derived component for skewing the immune response toward Th2.

Site-specific sensitization in a murine model of allergic rhinitis: role of the upper airway in lower airways disease

BACKGROUND

Allergic rhinitis (AR) is the most common atopic disease with strong links to asthma. We have developed a murine model of AR to study nasal, bronchial, and systemic immune response to local allergen stimulation.

OBJECTIVES

The purpose of this study was to develop and characterize a murine model of AR.

METHODS

Six- to 8-week-old BALB/c mice were sensitized by means of intranasal (local) application of ovalbumin (OVA) or systemic intraperitoneal injection. They were then challenged with intranasal OVA, and allergic response was assessed.

RESULTS

Intranasal particle deposition was found to be exclusively in the nares. All sensitized animals showed increased levels of OVA-specific serum IgE and IgG after challenge, although the timing to maximal response varied with the route and dose of allergen used. Histology of the upper and lower airways showed marked eosinophilic infiltration, and analysis of bronchoalveolar lavage fluid showed increased IL-5 and PMN infiltrates after challenge.

CONCLUSION

Using exclusive local sensitization and challenge of mouse nares, we were able to demonstrate inflammatory changes in both the upper and lower airways, even though distribution of allergen particles appeared to be only in the nares of these animals. This provides further evidence for the importance of the upper airway in lower airways disease. We have shown that the route of administration greatly affects the characteristics of the subsequent immune responses.

Intranasal application of purified protein derivative suppresses the initiation but not the exacerbation of allergic rhinitis in mice

BACKGROUND

Several epidemiological and experimental studies have demonstrated that exposure to pathogens such as those from the genus Mycobacterium leads to the suppression of allergic sensitization and inflammation. However, little is known as to whether pathogen-derived soluble antigens have the potential to modulate the pathogenesis of allergic rhinitis.

OBJECTIVE

We sought to determine whether application of purified protein derivative (PPD) from Mycobacterium tuberculosis can suppress the initiation and/or exacerbation of allergic rhinitis using a recently developed murine model.

METHODS

First, we investigated whether a single intranasal application of PPD could elicit cytokine production in the nose by RT-PCR. BALB/c mice were repeatedly sensitized with Schistosoma mansoni egg antigen (SEA) intranasally without an adjuvant. PPD was applied through different routes either before or after sensitization. The production of SEA-specific antibodies, nasal eosinophilia and cytokines by nasal lymphocytes was compared among mice that had or had not received PPD treatment.

RESULTS

IFN-gamma, but not IL-4, was detected in the nasal tissue 12 to 48 h after a single intranasal application of 10 microg PPD. Repeated intranasal application of PPD prior to and during sensitization with SEA significantly inhibited the production of both SEA-specific IgE/IgG1 and nasal eosinophilia. Moreover, it partially inhibited the production of IL-4 by nasal lymphocytes in response to SEA. Conversely, this treatment led to a significant increase in IFN-gamma production. On the other hand, PPD applied through the footpad had no effect over the same period. Repeated intranasal application of PPD after sensitization with SEA had no exacerbative effect on allergic inflammation.

CONCLUSION

These results indicate that the local application of PPD, and the subsequent induction of IFN-gamma, inhibits the initiation, but not the exacerbation, of allergic rhinitis in mice. This suggests that pathogen-derived antigens have potential for use in the prevention and prophylaxis of allergic rhinitis.

Differential role of CD80 and CD86 molecules in the induction and the effector phases of allergic rhinitis in mice

Selective involvement of CD80 and/or CD86 in the differentiation of T-helper (Th)1 and Th2 was seen in several diseases. In this study, we sought to determine the differential roles of CD80 and CD86 in the induction and effector phase of allergic rhinitis using Schistosoma mansoni egg antigen (SEA) as a specific Ag. Intranasal sensitization with SEA in BALB/c mice elicited a strong Th2 response including SEA-specific IgE production, nasal eosinophilia, and IL-4 and IL-5 production by nasal lymphocytes after Ag challenge. Blockade of CD80 at the induction phase significantly inhibited these manifestations, whereas no effect was observed by CD86 blockade. In contrast, the simultaneous blockade of both CD80 and CD86 during the effector phase partially inhibited IgE and IgG(1) production and nasal eosinophilia, although either blockade of CD80 or CD86 during the phase failed to inhibit these responses. Flow cytometric analysis on nasal mononuclear cells showed that CD80 but not CD86 was preferentially expressed on non-B cells by in vitro SEA stimulation in unsensitized mice. However, both CD80 and CD86 expression were significantly augmented by in vitro SEA stimulation in sensitized mice. Our results suggest the differential roles and expression of CD80 and CD86 in the development of allergic rhinitis.

Lacto-N-fucopentaose III found on Schistosoma mansoni egg antigens functions as adjuvant for proteins by inducing Th2-type response

We have recently demonstrated that induction of Th2 responses by Schistosoma mansoni egg Ag is largely due to carbohydrates on the Ag functioning as adjuvants. Lacto-N-fucopentaose III (LNFPIII), a polylactosamine sugar, is the predominant carbohydrate found in S. mansoni egg Ag. Therefore, using neoglycoprotein, we investigated whether LNFPIII induces in vivo Th2 response and functions as an adjuvant. Following intranasal immunization with LNFPIII linked to human serum albumin (HSA) (HSA-LNFPIII), BALB/c mice mounted a strong Th2 response and produced significantly higher levels of total IgE as well as HSA-specific IgG, IgG1, and IgE. HSA-LNFPIII was over 1000-fold more potent in inducing Ab production as compared with HSA alone. Although LNFPIII itself did not function as an epitope for either IgG or IgE, its conjugation with protein was essential for the adjuvant activity. Moreover, fucose residue on LNFPIII was crucial for induction of Ab production. Nasal lymphocytes from mice immunized with HSA-LNFPIII produced IL-4, IL-5, and IL-10, but not IFN-gamma following in vitro stimulation with HSA or HSA-LNFPIII. In addition, these activated nasal lymphocytes also showed a significant increase of B7-2 expression on B220-positive cells. Furthermore, not only intranasal but also both i.p. and s.c. immunization with HSA-LNFPIII induced significant production of HSA-specific Abs compared with the immunization with HSA alone, suggesting that the activity of LNFPIII was not restricted on particular route of immunization. These results demonstrate that Lewis type carbohydrate LNFPIII can function as an adjuvant by their ability to induce a Th2 response.

Induction, distribution and modulation of upper airway allergic inflammation in mice

BACKGROUND

To further elucidate mechanisms of human allergic rhinosinusitis, we studied the induction, distribution and modulation of allergen-induced upper airway inflammation in a BALB/c mouse model.

METHODS

Allergic inflammation induced with ovalbumin (OVA) by intraperitoneal (IP) injection in alum was compared to repeated intranasal instillation. The type and distribution of inflammatory cells was compared in the respiratory and olfactory epithelial compartments. Eosinophil distribution was assessed using Scarlet Red stain and a polyclonal antibody recognizing eosinophil major basic protein (MBP). The role of interleukin (IL)-5 in upper airway inflammation was tested by administration of polyclonal anti-IL-5 antibody during the sensitization protocol.

RESULTS

Unsensitized control mice receiving saline failed to develop upper airway eosinophil infiltration. IP OVA-sensitized mice developed marked upper airway mucosal eosinophil infiltration after aerosol OVA challenge, whereas repeated intranasal instillation of OVA produced qualitatively similar, but less intense eosinophil infiltration. Using either sensitization protocol, eosinophil infiltration was seen in areas of the lower portion of the nasal septum, the floor and the lower lateral walls of the mid-caudal region of the nasal cavity. Immunofluorescence staining for MBP confirmed this distribution of eosinophils but also demonstrated some eosinophils in the maxillary sinuses and in circumscribed regions of the ethmoturbinates. All areas of eosinophil infiltration were lined by respiratory epithelium. The selective infiltration of respiratory but not olfactory epithelium by eosinophils was unassociated with a measurable induction of epithelial ICAM-1 or eotaxin expression. OVA-induced upper airway eosinophil infiltration was found to be IL-5 dependent, since administration of a polyclonal anti-IL-5 antibody (TRFK-5) during OVA sensitization resulted in a marked modulation (80% decrease) in eosinophil infiltration in response to subsequent OVA challenge.

CONCLUSION

The mouse upper airway, specifically in areas containing respiratory epithelium, is a target for OVA-induced allergic inflammation. This selective infiltration of respiratory, but not olfactory, epithelium is, in part, dependent upon IL-5. This model is useful for further dissection of the inflammatory response with genetic manipulations and targeted immunological approaches.

Sex-related differences in the initiation of allergic rhinitis in mice

BACKGROUND

Several clinical and epidemiologic studies have investigated sex differences in the prevalence of allergic rhinitis. At present, however, no reports have demonstrated such differences in experimental models with local, but not parenteral, sensitization with antigens that may reflect natural exposure to allergens. We have recently developed murine models of allergic rhinitis after repeated intranasal sensitization with antigens in the absence of adjuvants. In this study, we investigated the role of sex in the initiation of the disease in vivo.

METHODS

Male and female CBA/J and BALB/c mice were sensitized intranasally with phospholipase A2 (PLA2) and Schistosoma mansoni egg antigen (SEA), respectively, in the absence of adjuvants. After the repeated sensitization, serum Ab titers against the sensitizing antigen and nasal eosinophilia were determined. In addition, the involvement of androgen in IgE synthesis was investigated in castrated CBA/J male mice with or without testosterone administration.

RESULTS

Females produced significantly higher levels of PLA2-specific IgE than males in CBA/J mice sensitized with PLA2. On the other hand, both titers of PLA2-specific IgG1 and nasal eosinophilia did not significantly differ between the two groups. Castrated male mice produced significantly higher amounts of PLA2-specific IgE than sham-treated male mice. In addition, PLA2-specific IgE production decreased in castrated mice treated with testosterone. Sexual differences in the production of Ag-specific IgE were not seen in BALB/c mice after the sensitization with SEA.

CONCLUSION

These results suggest that sex is responsible for the production of Ag-specific IgE, but not IgG1 or nasal eosinophilia, and that androgen appears to be involved in the in vivo production of specific IgE in male mice.

Interleukin-4-independent production of Th2 cytokines by nasal lymphocytes and nasal eosinophilia in murine allergic rhinitis

BACKGROUND

Interleukin (IL)-4 is believed to play an important role in the atopic pathogenesis. However, the precise role of IL-4 in the in vivo initiation of allergic rhinitis is not fully understood. We have recently found that BALB/c mice sensitized intranasally with Schistosoma mansoni egg antigen (SEA) mount a Th2 response that initiates allergic rhinitis. Thus, we sought to determine the role of IL-4 in the initiation of allergic rhinitis in vivo with this model.

METHODS

IL-4 gene-deficient (IL-4 -/-) BALB/c and wild-type (IL-4 +/+) control mice were sensitized by intranasal SEA administration, and their immunologic responses were examined both in vivo and in vitro.

RESULTS

IL-4 +/+ mice sensitized with SEA displayed significantly higher titers of SEA-specific IgG1 and IgE antibodies than IL-4-/- mice, while the latter produced significantly more SEA-specific IgG2a. Antigen-stimulated nasal lymphocytes from SEA-sensitized IL-4 -/- and IL-4 +/+ mice produced similar amounts of IL-5 and IL-10, but neither produced IFN-gamma. Furthermore, the severity of nasal eosinophilia was similar in both groups.

CONCLUSIONS

These results indicate that although IL-4 is necessary for the production of Th2-associated antibodies--in particular, IgE--it is not required for either the production of the Th2-associated cytokines IL-5 and IL-10, or the induction of nasal eosinophilia.

Induction of Th2 Responses and IgE Is Largely Due to Carbohydrates Functioning as Adjuvants on Schistosoma mansoni Egg Antigens

Infection with the helminth parasite Schistosoma mansoni induces a pronounced Th2-type response that is associated with significant IgE production. To better understand how the parasite drives these responses, we investigated the relative roles of proteins and carbohydrates in driving Th2-type and/or IgE responses using a murine model of intranasal sensitization with soluble egg Ags (SEA) of Schistosoma mansoni. We found that repeated intranasal sensitization with soluble egg Ags led to the induction of both total and specific IgE production and nasal eosinophilia. By comparing the responses of mice sensitized with SEA or metaperiodate-treated SEA we were able to demonstrate that carbohydrates on SEA are the major inducers of IgE production and nasal recruitment of eosinophils. Mice sensitized with periodate-treated SEA displayed a significant decrease in both total and specific IgE levels in comparison to mice sensitized with native SEA. Furthermore, sensitization of mice with periodate-treated SEA significantly reduced levels of Ag-specific IgG1, but had no effect on IgG2a production. Nasal lymphocytes from mice sensitized with native SEA, but not with periodate-treated SEA, produced IL-4, IL-5, and IL-10 when restimulated with native SEA in vitro. On the other hand, lymphocytes from mice sensitized with periodate-treated SEA did not produce any of these same cytokines following in vitro restimulation, suggesting that carbohydrates were required for in vivo induction of Th2 response and for that of associated cytokine responses in this model. Lastly, competitive inhibition ELISA showed that although carbohydrates are required for SEA-specific IgE induction, they are not targets of the induced IgE response.