Specific IgE Production Research Articles

Antigen dose‐dependent suppression of murine IgE responses is mediated by CD4−CD8− double‐negative T cells

The IgE response against protein antigens is profoundly influenced by the dose used for sensitization. The aim of the study was to identify immune cells that are involved in antigen dose-dependent regulation of IgE formation. Wild-type mice as well as T helper (Th)1-deficient IL-12p40(-/-) and IFN-gamma(-/-) mice were immunized by repeated intraperitoneal injection of either low doses (K01 mice) or high doses (K100 mice) of keyhole limpet haemocyanin adsorbed to aluminium hydroxide. Splenocytes of immunized mice were restimulated in vitro and antigen-dependent T cell proliferation and cytokine production were measured. The frequency of regulatory T cell subsets among splenocytes from K01 and K100 mice was compared using fluorocytometry and RT-PCR analysis. Splenocytes or T cell subpopulations were transferred into naïve mice and the effect of lymphocyte transfer on IgE production after priming of recipients with low antigen doses was determined. Specific IgE production was considerably impaired in K100 mice. Antigenic restimulation revealed hypoproliferation of K100 splenocytes and reduced production of Th2 cytokines IL-4, IL-5 and IL-13, but no induction of IFN-gamma production. Moreover, lymphocytes from K01 and K100 mice did not show significant differences in the expression of molecules associated with the phenotype or activity of conventional regulatory T cells. Transfer of splenocytes or purified T cells from K100 mice substantially suppressed the induction of IgE production in the recipients in an antigen- and isotype-specific manner. Neither CD4(+) nor CD8(+) T cells from K100 mice were able to inhibit IgE formation; instead, we identified CD4(-)CD8(-) double-negative T cells (dnT cells) as the principal T cell population, which potently suppressed IgE production. Our data demonstrate that CD4(-)CD8(-) dnT cells play a major role in the regulation of IgE responses induced by high antigen doses.

The Editor takes a closer look at some of this month's articles

Clinical & Experimental AllergyVolume 40, Issue 7 p. 957-957 Free Access The Editor takes a closer look at some of this month's articles First published: 10 June 2010 https://doi.org/10.1111/j.1365-2222.2010.03555.xAboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Clinically relevant local IgE production: doubt no more? There is now convincing evidence, much of which is quoted in the Opinions article by Powe and colleagues (pp. 987–997), that tissue production of specific IgE occurs in allergic disease. A number of authorities including Powe et al. as well as Peter Barnes in an Opinions paper last year [1], have argued that this is the explanation for intrinsic allergic disease. In other words the difference between extrinsic allergic disease and non-atopic disease is that in the former the specific IgE gets into the blood and in the latter it doesn't, although if this is the case the reasons remain unknown. If this hypothesis were correct then allergen challenge in intrinsic disease would also result in an early and late response. As inclusion criteria for allergen challenge is a positive skin prick test or circulating specific IgE this is not often done in non-atopic subjects. However Lopez and colleagues (pp. 1007–1014) have convincingly shown that patients who they describe as having ‘local allergic rhinitis’ (defined as people with perennial symptoms to dust mite with negative circulating specific IgE), have both early and late responses to allergen challenge measured by symptoms and mediator release including mast cell tryptase. This is an important and exciting observation, not least because it suggests that anti-allergic therapy including specific immunotherapy and omalizumab would be beneficial in intrinsic disease. [ (see Fig. 1 in Powe et al.) ] Twin studies: worth their weight Two papers in this issue illustrate the considerable value of twin studies, particularly those from the impressive Scandinavian twin registries where detailed information is available on large numbers of subjects. Thomsen et al. (pp. 1054–1061) have used the Danish Twin Registry which contains information on asthma in over 20 000 twins to measure the hereditability of asthma, confirming previous studies of a strong genetic element in young children and adults, and showing that this does not extend to older adults. Lundholm et al. (pp. 1044–1053) have interrogated the Swedish twin registry containing data on allergic disease in over 10 000 twins to definitively show that increased birth weight is a risk factor for the development of eczema, but interestingly not allergic rhinitis, independently of confounding factors such as gestational age and environmental and genetic factors. Two powerful studies generating novel and important data. [ Twins (courtesy of Wikipedia) ] Food allergy: go easy on the antacids There is increasing evidence that neutralization of stomach acid increases the risk of food allergy, presumably by preventing effective protein digestion, which in turn leads to larger amounts of allergen protein reaching the small intestine and being systemically absorbed [2, 3]. Further support for the importance of this pathway comes from Pali-Scholl et al. (pp. 1091–1098). They demonstrated in vitro that increasing the pH prevented the digestion of codfish antigens. They then demonstrated in a mouse model that co-feeding the animals codfish with antacids caused increased production of fish specific IgE and the development of a positive intradermal skin test. As they point out the widespread over-the-counter use of antacid tablets and powders could be one explanation for the increase in the incidence of food allergy, particularly in adults. [ Antacid tablets (courtesy of Wikipedia) ] References 1 Barnes PJ. Intrinsic asthma: not so different from allergic asthma but driven by superantigens? Clin Exp Allergy 2009; 39: 1145– 51. CASPubMedWeb of Science®Google Scholar 2 Kemp AS. Allergy and gastric acid suppression. Clin Exp Allergy 2009; 39: 176– 8. Wiley Online LibraryCASPubMedWeb of Science®Google Scholar 3 Dehlink E et al. First evidence of a possible association between gastric acid suppression during pregnancy and childhood asthma: a population-based register study. Clin Exp Allergy 2009; 39: 246– 53. CASPubMedWeb of Science®Google Scholar Volume40, Issue7July 2010Pages 957-957 ReferencesRelatedInformation

Local allergic rhinitis: a new entity, characterization and further studies

The purpose of this review is to describe new insights into the pathophysiology and clinical characterization of 'local allergic rhinitis', a new phenotype of rhinitis that may affect individuals previously diagnosed with nonallergic rhinitis. Several studies have shown the existence of local allergic rhinitis with nasal production of specific IgE (sIgE) antibodies in the absence of atopy in over 40% of nonallergic rhinitis patients. Evidence for this entity is supported by the clinical symptoms, the local production of sIgE and a leukocyte-lymphocyte inflammatory pattern, with an increase in the nasal fluids of eosinophils, mast cells and T lymphocytes during natural exposure to aeroallergens, as well as a positive immediate and dual response to a nasal allergen provocation test with local production of tryptase and eosinophil cationic protein and an increase of nasal sIgE to inhalant allergens. On the basis of these new findings, an advanced diagnostic approach is proposed in patients with symptoms suggestive of allergic rhinitis but negative results in skin prick test and serum sIgE. Detection of local sIgE in nasal secretions during natural exposure to aeorallergens and a positive nasal allergen provocation test with local production of tryptase, eosinophil cationic protein and sIgE are useful to detect patients with local allergic rhinitis.

Nasal inflammatory mediators and specific IgE production after nasal challenge with grass pollen in local allergic rhinitis

Evidence exists of a new form of local allergic rhinitis (LAR) with local production of specific IgE (sIgE) and a positive response to nasal allergen provocation test (NAPT) in patients previously diagnosed with idiopathic rhinitis. However, the immunologic mechanisms involved are still poorly understood. We explored the involvement of nasal sIgE, eosinophil, and mast cell activation in the response to NAPT with grass pollen (NAPT-grass) in a group of patients already classified with LAR. Out-of-spring NAPT-grass was performed in 30 patients with LAR and 30 healthy controls. Nasal symptoms, acoustic rhinometry, and nasal lavage were performed at baseline and 15 minutes and 1, 6, and 24 hours post-NAPT. Tryptase, eosinophilic cationic protein (ECP), and total and sIgE to grass pollen were measured in nasal lavage by immunoassays. NAPT-grass was positive in all patients with LAR. We detected significant increases of tryptase and ECP in 40% and 43%, respectively, at 15 minutes and 1, 6, and 24 hours post-NAPT compared with baseline (P < .05). sIgE was increased in 30%, with significant increases at 1 and 6 hours (P < .05) and 24 hours (P = .002) post-NAPT. The maximum release of tryptase was detected 15 minutes after NAPT, whereas the maximum release of ECP and sIgE was detected 24 hours after challenge. NAPT-grass was negative in all healthy controls, with no increase in tryptase, ECP, total IgE, or sIgE. These results demonstrate that patients with LAR had local production of sIgE and mast cell/eosinophil activation induced by nasal exposure to grass pollen.

Characteristics of Nonallergic Vasomotor Rhinitis

Nonallergic rhinitis (NAR) conditions are currently considered diagnoses by exclusion. A diagnosis of NAR requires negative specific IgE responses by skin or serologic testing and more recently testing to exclude localized production of specific IgE in the nose. Symptoms are classically aggravated by irritant triggers such as tobacco smoke, perfumes/fragrances, and temperature or barometric pressure changes. A previously developed questionnaire survey designed to help physicians recognize differences between allergic rhinitis and nonallergic rhinitis subtypes found that patients with symptom onset later in life (> 35 years), no family history of allergies, no seasonality or cat-induced symptoms, and symptoms induced by perfumes and fragrances had > 95% likelihood of having a physician diagnosis of NAR. Of note, clinical symptoms were not generally useful for differentiating chronic rhinitis subtypes which has also been confirmed in a more recent study investigating the relationship between headaches and chronic rhinitis subtypes (Table 1). In subsequent studies it was found that a significant percentage of NAR patients did not experience irritant-induced symptoms, suggesting that these triggers are not a clinical characteristic that can be uniformly used for all NAR patients. However, a newly developed Irritant Index Scale can be used to reliably differentiate pure allergic rhinitis from nonallergic rhinitis with trigger phenotypes. The use of standardized and validated questionnaires allows objective characterization of chronic rhinitis subtypes that appears to improve the accuracy of clinically diagnosing these patients.

Ortho-Phthalaldehyde enhances allergen-specific IgE production without allergen-specific IgG in ovalbumin-sensitized mice

ortho-Phthalaldehyde (OPA) is commonly used as a safer and more effective chemical disinfectant for use with medical devices in hospitals. However, the cases of patients with occupational bronchial asthma or contact dermatitis are recently reported among workers in the medical professions who were exposed to OPA disinfectant. Mechanism of allergic reaction associated with OPA is poorly understood. The purpose of this study is that OPA may act as an immunological adjuvant in the allergic reaction accompanied by enhanced specific-IgE production in response to allergen challenge in OVA-sensitized mice. OPA induced increase of total cell numbers, and reflected infiltration of neutrophils in BAL fluid after allergen challenge in sensitized mice, dose-dependently. However, total protein concentration in BAL fluid did not change in the all of groups. The OPA induced up-regulation of eotaxin and monocyte chemotactic protein-1 mRNAs in the lung as well as the increase in OVA-specific IgE in sensitized mice compared with non-sensitized controlled mice without increase in the level of OVA-specific IgG. Cytokines IL-4 and IL-5 mRNA were expressed by allergen (OVA) challenge in both lungs collected from OPA-administrated-sensitized and OPA-administrated-nonsensitized mice. From these data, we concluded that low concentration of OPA that enhanced the OVA-induced recruitment of neutrophils to the lung and the production of allergen-specific IgE, suggesting that OPA acts as an immunological adjuvant.

Comparative study of the adjuvanticity of Bacillus thuringiensis Cry1Ab protein and cholera toxin on allergic sensitisation and elicitation to peanut

We aimed to investigate the adjuvanticity of Cry1Ab on allergic sensitisation and elicitation to peanut in mice, in comparison with cholera toxin (CT), a known mucosal Th2 adjuvant. Balb/c mice were gavaged with phosphate buffer saline (PBS) (control), peanut protein extract (PE) alone or PE co-administered either with CT or Cry1Ab. Peanut-specific IgE, IgG1 and IgG2a and Th1/Th2/Th17 cytokine secretion by splenocytes were assayed. Gavaged mice were further challenged with PE. Markers of the immediate and late phases of the allergic reaction were assayed in bronchoalveolar lavages (BAL) fluids collected 10 minutes or 36 hours after airway challenge, respectively. Sensitisation to peanut was only observed in mice receiving PE plus CT, as demonstrated by specific IgE and IgG1 production in sera and secretion of Th2 (and Th17) cytokines by splenocytes. Following challenge, mice sensitised with PE plus CT produced leukotrienes (LT) E4 and C4, then Th2/Th17-cytokines and showed eosinophil/neutrophil influx in BAL. Interestingly, LT production, Th2/Th17 cytokine release and eosinophil influx were also significant in mice gavaged with PE plus Cry-1Ab, but not with PBS or PE alone. Cry1Ab did not demonstrate adjuvant effects on oral sensitisation to peanut. However, this study shows possible adjuvant properties of Cry1Ab on the elicitation of the allergic reaction, at least in the Balb/c mouse model and in the experimental conditions used.

Pravastatin attenuates allergic airway inflammation by suppressing antigen sensitisation, interleukin 17 production and antigen presentation in the lung

Background:Statins are widely used to treat hyperlipidaemia. Their immunosuppressive effect has recently been confirmed in various immune mediated disease models. However, relatively few studies have been conducted on allergic inflammation,...

Single Non-Viral Antigen Exposure During a Paramyxoviral Respiratory Infection is Sufficient to Drive Specific IgE Production

Single Non-Viral Antigen Exposure During a Paramyxoviral Respiratory Infection is Sufficient to Drive Specific IgE Production

The Effects of Microbial Materials Adhered to Asian Sand Dust on Allergic Lung Inflammation

Asian sand dust (ASD) containing microbiological materials, sulfate (SO(4)(2)), and nitrate (NO(3)(-) ) derived from air pollutants in East China, reportedly cause adverse respiratory health effects. ASD aggravates ovalbumin (OVA)-associated experimental lung eosinophilia. In this study, the toxic materials adsorbed onto ASD were excluded by heat treatment at 360 degrees C for 30 min. The effects of nonheated ASD or heated ASD (H-ASD) toward the allergic lung inflammation were compared in murine lungs. ICR mice were administered intratracheally with normal saline (control), H-ASD, ASD, OVA, OVA + H-ASD, and OVA + ASD, four times at 2-week intervals. ASD only increased neutrophils in bronchoalveolar lavage fluids (BALFs) along with pro-inflammatory mediators, such as keratinocyte chemoattractant (KC). H-ASD and ASD enhanced eosinophil recruitment induced by OVA in the alveoli and in the submucosa of the airway, which has a goblet cell proliferation in the bronchial epithelium. The two ASDs synergistically increased interleukin-5 (IL-5), monocyte chemotactic protein-3 (MCP-3), and eotaxin, which were associated with OVA, in BALF. The enhancing effects were much greater in ASD than in H-ASD. The two ASDs induced the adjuvant effects to specific IgE and IgG1 production by OVA. In the in vitro study using RAW264.7 cells, ASD increased the expression of Toll-like receptor 2 (TLR 2) mRNA but not TLR4 mRNA. H-ASD caused no expression of either TLR mRNA. These results suggest that the aggravated lung eosinophilia by ASD may be due to activation of Th2-associated immune response via the activation of TLR2 by microbial components adhered to ASD.

Allergen immunotherapy for allergic rhinitis

Introduction Allergic rhinitis—the most common allergic disease—is characterized by sneezing, clear rhinorrhea, nasal itching, congestion, and itchy, watery eyes [1]. Despite advances in immunology, allergic rhinitis remains a significant health issue affecting approximately 30% of adults and 40% of children [2]. Its prevalence is increasing, especially in Western countries [3]. The morbidity of allergic rhinitis is significant, inflicting high costs on society through lost work and school time. Allergic rhinitis “is a symptomatic disorder of the nose induced by an IgE [immunoglobulin E]-mediated inflammation after allergen exposure of the membranes lining the nose” [4]. In an atopic individual, allergen exposure causes specific IgE production, which binds to mast cell surfaces. Upon reexposure, the allergen crosslinks IgE on the mast cells, leading to degranulation and release of histamine and other inflammatory mediators [3]. Recommended treatments depend on severity of the disease [4]. Treatments include allergen avoidance, antihistamines, intranasal steroids, antileukotriene receptor antagonists, mast cell stabilizers, and decongestants. Despite treatment, many patients continue to exhibit symptoms. In addition, these treatments offer only symptomatic relief; none has been shown to abate disease activity. However, immunotherapy has been used with success and is the only treatment that may alter disease activity. Subcutaneous immunotherapy (SCIT) requires injections one to three times a week of extracts at increasing concentrations until a maintenance dose is reached. Then, the maintenance dose is given for 3 to 5 years. Reactions to SCIT, which range from mild erythema surrounding the injection site to anaphylaxis, resulted in a search for alternative routes of delivery. Consequently, sublingual immunotherapy (SLIT) has been suggested as an alternative, and is already used routinely in European countries [5]. SCIT has been shown to alter levels of antibodies in the blood, decrease reactions to specific allergen skin testing, and alter the immune response from T helper (Th) 2 (allergic) to Th1 (nonallergic) [6]. The immunologic effect of sublingual immunotherapy is less clear. This review examines SCIT and SLIT as treatments for allergic rhinitis when compared with placebo.

Enhanced Production of IgE Anti-Japanese Cedar Pollen Specific Antibodies by Peripheral Blood B Cells from Patients with Japanese Cedar Pollinosis

IgE antibodies against Japanese cedar pollen (JCP) play an important role for the pathogenesis of the cedar pollinosis, but the mechanism of their production has been unclear. We explored the capacity of peripheral blood B cells from pollinosis patients to produce anti-JCP specific IgE. Peripheral blood B cells from 16 pollinosis patients and 9 normal subjects were cultured with mitomycin-C treated T cells with immobilized anti-CD3 for 10 days. B cells from pollinosis patients produced higher amounts of anti-JCP specific IgE than those from normal subjects upon stimulation with immobilized anti-CD3 activated autologous T cell, whereas the production of anti-JCP specific IgM were comparable between normal subjects and patients. Exogenous IL-4/IL-5 or anti-CD3 stimulated patients' T cells could not induce the production of anti-JCP specific IgE from normal B cells. These results indicate that B cells from normal individuals contain comparable numbers of precursors that are committed to produce anti-JCP specific IgM to patients' B cells. Moreover, the data confirm that the class switching of IgM to IgE within anti-JCP specific B cells contributes to development of Japanese cedar pollinosis.

Local immunoglobulin production in nasal polyposis is modulated by superantigens

Chronic rhinosinusitis (CRS) with nasal polyps (NP) represents a persistent inflammation often characterized by local hyper-immunoglobulinaemia and the presence of specific IgE to Staphylococcus aureus enterotoxins (SAEs). We aimed to study the systemic and local production of Igs in relation to plasma cells, B cells and specific IgE to SAEs. Concentrations of IgE, IgG, IgM, IgA, IgG subclasses and specific IgE to SAE were determined on tissue homogenates and serum from 15 CRS patients with NP, 15 CRS without NP and 10 control patients. Tissue cryo-sections were stained for CD19, CD20 and CD138 to demonstrate B and plasma cells. IgA, IgG and IgE concentrations were significantly higher in tissue homogenates, but not in serum, of NP compared with CRS and control subjects. NP with specific IgE to SAEs had significantly higher concentrations of IgG and IgE, and also showed a significantly higher fraction of IgG4 (P=0.003) and a lower fraction of IgG2 (P=0.04) than those without specific IgE production. Furthermore, naïve CD19(+) B cell and plasma cell counts (CD138(+)) were significantly higher in NP tissue compared with controls or CRS. The difference in IgE, IgG and IgA expression between NP tissue and serum, supported by increased numbers of plasma cells, suggests a local production of these Igs in NP in response to a chronic microbial trigger. The local immune response to SAE is associated with a further increased production of IgE and IgG, and a shift in IgG subclasses.

The IgE repertoire in PBMCs of atopic patients is characterized by individual rearrangements without variable region of the heavy immunoglobulin chain bias

Patients with atopic diseases are characterized by high levels of specific IgE production. However, little is known about the composition of their B-cell repertoires. We sought to analyze the complete PBMC-derived IgE repertoire and to compare clonal expansions between different patients. We have analyzed the IgE-bearing B-cell receptor repertoire in highly atopic patients (>1000 IU/mL) using quantitative RT-PCR, complementarity determining region 3 spectratyping, and sequence analysis. Three representative patients were additionally followed during anti-IgE therapy. Atopic patients exhibited 100 to 1000 times more IgE-specific transcripts than control individuals. These patients used a variable region of the heavy immunoglobulin chain (VH) epsilon repertoire highly similar to their IgM and IgG repertoires, with preference of VH3b, VH4, VH3a, and VH1 segments. Each patient harbored individual clonal expansions, most probably as correlation of allergen-specific IgE production. Common expansions within the complementary determining region 3 shared by several individuals with similar sensitization patterns were found in spectratyping analysis. However, these antigen-driven expansions showed differences on the sequence level. In omalizumab-treated patients the clinical improvement was paralleled by a clear increase in the ratio of IgG/IgE transcripts. The IgE repertoire in atopic patients follows the VH use patterns seen for other immunoglobulins and seems to preferentially recruit individual rearrangements rather than public expansions. The detailed analysis of the IgE B-cell repertoire is highly suitable to follow changes in IgE uses during different therapy modalities.

Formalin-Fixed Staphylococcus aureus Particles Prevent Allergic Sensitization in a Murine Model of Type I Allergy

Background: Bacterial infections are supposed to act counterregulatory to the development of allergen-specific Th2 immune responses. We analyzed whether administration of extracellular Staphylococcus aureus inhibited experimental sensitization against allergens. Methods: BALB/c mice were immunized with alum-adsorbed ovalbumin (OVA) together with formalin-fixed Staphylococcus particles. OVA-specific antibody production and cytokine synthesis by spleen cells was analyzed. Airway reactivity and cellular infiltration into the airways was assessed after intranasal challenge of mice with OVA. In addition, the capacity of Staphylococcus particles to modulate cytokine production by bone marrow-derived dendritic cells was analyzedin vitro. Results: Simultaneous application of OVA and Staphylococcus particles very efficiently inhibited production of specific IgE and IgG1 as well as secretion of IL-4 and IL-5 by splenocytes, while enhancing IgG2a formation and production of IFN-γ, indicating a shift from a Th2 response towards a Th1-biased response. This effect was not dependent on the expression of protein A by Staphylococcus. An enhanced frequency or activity of regulatory T cells after administration of Staphylococcus particles was not apparent. Treatment of mice with Staphylococcus particles during the sensitization phase prevented lung inflammation (airway hyperreactivity, eosinophilia) after local challenge with OVA. Culture of bone marrow-derived dendritic cells with Staphylococcus particles induced IL-12p35 and p40 mRNA expression as well as secretion of IL-12p70, and increased production of IL-10 mRNA and protein. Conclusions: Administration of formalin-fixed Staphylococcus particles induced Th1-biased immune responses and prevented allergic sensitization.

Prenatal versus postnatal sensitization to environmental allergens in a high-risk birth cohort

The timing of allergen sensitization is controversial, with conflicting evidence suggesting transplacental priming versus exclusively postnatal priming. Resolution of this question is important in relation to rational design of allergy prevention strategies, particularly the issue of allergen avoidance during pregnancy. To elucidate the kinetics of sensitization in high-risk children during their first 2 years of life. We prospectively studied house dust mite (HDM)-specific IgE and IgG(4) antibody production and associated T-cell immunity in a cohort of 200 high-risk infants. Parallel antibody studies tracked responses against a broader panel of inhalant and dietary allergens including peanut. HDM-induced T(H)2 responses in PBMC from 6 months onward, particularly IL-4 and IL-5, correlated increasingly strongly with sensitization outcomes at 2 years, and a contrasting negative relationship was observed with IFN-gamma response capacity. HDM-induced T-cell responses in cord blood, although common, were unrelated to subsequent sensitization. Transient HDM-IgE (and IgG(4)) production frequently peaked at 6 or 12 months before returning to baseline, which suggests the onset of protective tolerance. This finding contrasted with progressively increasing HDM-IgE titers in children sensitized by 2 years of age. Comparably contrasting patterns were observed in peanut-specific responses in sensitized versus nonsensitized children. Priming of T(H)2 responses associated with persistent HDM-IgE production occurs entirely postnatally, as HDM reactivity in cord blood seems nonspecific and is unrelated to subsequent development of allergen-specific T(H)2 memory or IgE. These findings question the scientific basis for existing recommendations for allergen avoidance by high-risk women during pregnancy.

Development of a Novel Mouse Anaphylaxis Model Produced by Intermittent Intravenous Injections of Ovalbumin without Adjuvant

This study was performed to develop mouse anaphylaxis model using ovalbumin (OA) as an antigen, with no adjuvant, and an intravenous route of administration. OA at dose levels from 0.5 to 500 mg/kg was injected 3 times into the tail vein of female CD-1 (ICR) mice at 4-day intervals. Clinical signs and extravasation of Evans blue dye (vascular permeability) were observed, serum histamine levels and airway resistance were measured, and histopathological examinations were performed. Furthermore, to detect serum IgE and IgG, heterologous and homologous passive cutaneous anaphylaxis tests were performed. Additionally, strain differences in susceptibility to OA anaphylaxis was examined with 3 mouse strains: ICR, BALB/c and C57BL/6 mice. Shortly after the 3rd injection, most of the animals exhibited systemic anaphylactic signs including death, and this was accompanied by increases in vascular permeability, plasma histamine levels, and airway resistance. Four days after the 2nd injection, anti-OA IgE and IgG were detected in sera of mice injected with 0.5 and 5.0 mg/kg or higher doses of OA, respectively. Histological findings included: congestion in many tissues; detachment of mucosal epithelial cells in the gastrointestinal tract; enhanced death, decreased numbers of lymphocytes, and increased numbers of macrophages in the lymphoid tissues. ICR mice were shown to be most susceptible to the OA anaphylaxis of the 3 mouse strains examined. In conclusion, the results demonstrate that 3 intermittent intravenous injections of OA without adjuvant at 4-day intervals can induce anaphylactic shock in mice, in particular, most effectively in ICR mice, and that the anaphylaxis is characterized by specific IgE and IgG production.

Chondroitin Sulfate Intake Inhibits the IgE-mediated Allergic Response by Down-regulating Th2 Responses in Mice

Chondroitin sulfate (CS) was administered orally to BALB/c mice immunized intraperitoneally with ovalbumin (OVA) and/or dinitrophenylated OVA. The titers of antigen-specific IgE and IgG1 in mouse sera were determined. The antigen-specific IgE production by mice fed ad libitum with CS was significantly inhibited. We also examined the effect of feeding CS on immediate-type hypersensitivity. One hour after antigen stimulation, the ears of mice fed with CS swelled less than those of the control mice. Furthermore, the rise in serum histamine in the mice fed with CS under active systemic anaphylaxis was significantly lower than that in the controls. We next examined the pattern of cytokine production by splenocytes from mice followed by re-stimulation with OVA in vitro. The splenocytes from the mice fed with CS produced less interleukin (IL)-5, IL-10, and IL-13 than those from the control group. In contrast, the production of interferon-gamma and IL-2 by the splenocytes of mice fed with CS was not significantly different from those in the control mice. In addition, the production of transforming growth factor-beta from the splenocytes of mice fed with CS was significantly higher than that of the control mice. Furthermore, we showed that the percentages of CD4(+) cells, CD8(+) cells, and CD4(+)CD25(+) cells in the splenocytes of mice fed with CS are significantly higher than those of the control. These findings suggest that oral intake of CS inhibits the specific IgE production and antigen-induced anaphylactic response by up-regulating regulatory T-cell differentiation, followed by down-regulating the Th2 response.

Modified Th2 Responses at High-Dose Exposures to Allergen

The relationships between allergen exposures and allergy and asthma are complex. High exposure levels to cat allergen are associated with IgG- and IgG(4)-specific antibody responses without sensitization or risk of asthma, a process described as a "modified Th2 response." Attenuation of risk of allergy and asthma at high exposure levels has been reported in longitudinal studies of both childhood and occupational asthma. To investigate, using an occupational model, the relationships among estimated exposure to aeroallergens, the production of specific IgE, IgG and IgG(4) antibodies, and the prevalence of associated symptoms. Cross-sectional survey of employees exposed to rats at work on six pharmaceutical sites across the United Kingdom. A total of 689 (89%) provided a blood sample and completed a questionnaire. At highest exposure to rats, there was an attenuation of the exposure response for sensitization and symptoms. In contrast, the frequency of individuals producing high quantities of specific IgG and IgG(4) increased with exposure intensity. Ratios of IgG(4)/IgE were highest in those handling the greatest number of rats. Risk of developing work-related chest symptoms was lower for those who produced both specific IgE and IgG(4) compared to those with specific IgE only. High exposure to rats is associated with lower rates of specific IgE and symptoms but an increased frequency of high specific IgG and IgG(4) production. Specific IgG(4) produced together with specific IgE may reduce the risk of developing work-related chest symptoms compared with when specific IgE is produced alone.

Immunogenic and allergenic potentials of natural and recombinant innocuous proteins

A new aspect of protein immunogenic and allergenic properties has become important recently, when there is a higher chance that our immune system will be exposed to novel protein antigens and/or familiar protein antigens with an unprecedented high frequency and large amount. These proteins are innocuous, nontoxic, and noninvasive by themselves, and include various natural proteins from the environment and recombinant proteins from industry. The technical term allergenic has been used for such proteins and their abilities to induce specific IgE production and to cross-link IgE/Fc epsilonRI on the surface of mast cells and basophiles have been recognized. As for the environmental proteins, some physicochemical properties (solubility, stability, and permeability across a mucosal epithelium) of the proteins indirectly play important roles in their allergenic potential because they do not originate from invasive pathogens as vehicles. Indeed, several lines of experimental evidences have been accumulated indicating that all proteins are absorbed across mucosal epithelia by transcellular transport and/or through interstitial spaces among the epithelial cells but not at equal levels. Some animal models have been established for natural sensitization to some allergenic proteins by feeding or intragastric administration without an adjuvant and, in a few cases, some symptoms resembling human allergy and even anaphylaxis have been induced by oral challenge with the proteins. Sometimes, even to self-proteins, the immunogenic or allergenic potential is given by post-translational modifications and possibly by unknown structural/conformational alterations, when they are exogenous self-proteins, such as recombinant human proteins for drug use. Despite the accumulation of knowledge and the progress in analytical technology on protein allergenicity, it is still crucial to predict the allergenic potential of novel and unused proteins. However, some animal models are applicable for assessing the relative allergenic potential of processed proteins in comparison with that of native proteins in preclinical studies.