Platelets Independently Recruit into Asthmatic Lungs and Models of Allergic Inflammation via CCR3.

Platelet activation and pulmonary recruitment occur in patients with asthma and in animal models of allergic asthma, in which leukocyte infiltration, airway remodeling, and hyperresponsiveness are suppressed by experimental platelet depletion. These observations suggest the importance of platelets to various characteristics of allergic disease, but the mechanisms of platelet migration and location are not understood. The aim of this study was to assess the mechanism of platelet recruitment to extravascular compartments of lungs from patients with asthma and after allergen challenge in mice sensitized to house dust mite (HDM) extract (contains the DerP1 [Dermatophagoides pteronyssinus extract peptidase 1] allergen); in addition, we assessed the role of chemokines in this process. Lung sections were immunohistochemically stained for CD42b+ platelets. Intravital microscopy in allergic mice was used to visualize platelets tagged with an anti-mouse CD49b-PE (phycoerythrin) antibody. Platelet-endothelial interactions were measured in response to HDM (DerP1) exposure in the presence of antagonists to CCR3, CCR4, and CXCR4. Extravascular CD42b+ platelets were detected in the epithelium and submucosa in bronchial biopsy specimens taken from subjects with steroid-naive mild asthma. Platelets were significantly raised in the lung parenchyma from patients with fatal asthma compared with postmortem control-lung tissue. Furthermore, in DerP1-sensitized mice, subsequent HDM exposure induced endothelial rolling, endothelial adhesion, and recruitment of platelets into airway walls, compared with sham-sensitized mice, via a CCR3-dependent mechanism in the absence of aggregation or interactions with leukocytes. Localization of singular, nonaggregated platelets occurs in lungs of patients with asthma. In allergic mice, platelet recruitment occurs via recognized vascular adhesive and migratory events, independently of leukocytes via a CCR3-dependent mechanism.

A role for early oral exposure to house dust mite allergens through breast milk in IgE-mediated food allergy susceptibility.

BACKGROUND: Successful prevention of food allergy requires the identification of the factors adversely affecting the capacity to develop oral tolerance to food antigen in early life. OBJECTIVES: This study sought to determine whether oral exposure to Dermatophagoides pteronyssinus through breast milk affects gut mucosal immunity with long-term effects on IgE-mediated food allergy susceptibility. METHODS: Gut immunity was explored in 2-week-old mice breast-fed by mothers exposed to D pteronyssinus, protease-inactivated D pteronyssinus, or to PBS during lactation. We further analyzed oral tolerance to a bystander food allergen, ovalbumin (OVA). In a proof-of-concept study, Der p 1 and OVA levels were determined in 100 human breast milk samples and the association with prevalence of IgE-mediated egg allergy at 1 year was assessed. RESULTS: Increased permeability, IL-33 levels, type 2 innate lymphoid cell activation, and Th2 cell differentiation were found in gut mucosa of mice nursed by mothers exposed to D pteronyssinus compared with PBS. This pro-Th2 gut mucosal environment inhibited the induction of antigen-specific FoxP3 regulatory T cells and the prevention of food allergy by OVA exposure through breast milk. In contrast, protease-inactivated D pteronyssinus had no effect on offspring gut mucosal immunity. Based on the presence of Der p 1 and/or OVA in human breast milk, we identified groups of lactating mothers, which mirror the ones found in mice to be responsible for different egg allergy risk. CONCLUSIONS: This study highlights an unpredicted potential risk factor for the development of food allergy, that is, D pteronyssinus allergens in breast milk, which disrupt gut immune homeostasis and prevents oral tolerance induction to bystander food antigen through their protease activity.

Association between biomarkers and house dust mite sublingual immunotherapy in allergic asthma.

BACKGROUND: House dust mite (HDM) sublingual immunotherapy (SLIT) has demonstrated efficacy in clinical trials of patients with asthma. Airway inflammation is a characteristic of respiratory allergy, but its relationship to SLIT remains unclear. OBJECTIVE: We evaluate the association between clinical outcomes with pulmonary function and biomarkers in before and after HDM SLIT (UMIN Number 000022390). METHODS: One hundred twelve patients with asthma sensitized to HDM were randomized to add-on 6 standardized quality (SQ)-HDM SLIT to pharmacotherapy or pharmacotherapy alone for 48 weeks. At baseline and end of study, biomarkers, blood eosinophils, serum IgE, serum periostin, fractional exhaled nitric oxide (FeNO), and spirometry and clinical symptoms were measured. Association between biomarkers and an increase in FEV1 of 120 mL or greater were analysed. RESULTS: Sublingual immunotherapy (SLIT) demonstrated a significant reduction of serum periostin (P < .001), FeNO (P < .01), and increase in HDM-specific IgE (P < .05), FEV1 (P < .001) and improvement of clinical symptom scores, when compared to pharmacotherapy. The change in FEV1 correlated with the changes in serum periostin (r = .696, P < .001) and the changes in FeNO (r = .682, P < .001). The independent predictor of improvement in airflow limitation was changed in serum periostin (r2  = .753, P = .013) and FeNO (P = .038). Based on cut-off values derived by receiver operating characteristic analysis (periostin 30.9 ng/mL, FeNO 28.0 ppb), patients were distinguished responders from non-responders, but with no predictive value for blood eosinophils or total IgE. The proportion of patients with both high periostin and FeNO levels was significantly higher in responder than in non-responder (P = .026). CONCLUSIONS AND CLINICAL RELEVANCE: Adding HDM SLIT to pharmacotherapy resulted in reduced serum periostin and FeNO, and improved pulmonary function. Serum periostin and FeNO may be useful biomarkers for prediction of SLIT.

Tyrophagus putrescentiae group 4 allergen allergenicity and epitope prediction.

INTRODUCTION AND OBJECTIVES: Allergen-specific immunotherapy (ASIT) is the only allergic disease-modifying therapy available for children and adults, and recombinant allergens are an interesting approach to improve allergy diagnosis and ASIT. Tyrophagus putrescentiae is a common storage mite that produces potent allergens. The aim of this study was to express and characterize recombinant group 4 allergen protein of T. putrescentiae (Tyr p 4), and to further investigate allergenicity and potential epitopes of Tyr p 4. MATERIALS AND METHODS: The cDNA encoding Tyr p 4 was generated by RT-PCR and subcloned into pET-28a(+) plasmid. The plasmid was then transformed into E. coli cells for expression. After purification by nickel affinity chromatography and identification by SDS-PAGE, recombinant Tyr p 4 protein was used for a skin prick test and an ELISA to determine the allergic response. RESULTS: Study participants' allergic response rate to Tyr p 4 protein was 13.3% (16/120). Eight B-cell epitopes and three T-cell epitopes of Tyr p 4 were predicted. CONCLUSIONS: Similar to group 4 allergens of other species of mite, allergenicity of Tyr p 4 is weak. The expression, characterization and epitope prediction of recombinant Tyr p 4 protein provide a foundation for further study of this allergen in the diagnosis and ASIT of storage mite allergy.

Novel Mutant Phospholipase D from Hemiscorpius lepturus Acts as A Highly Immunogen in BALB/c Mice Against the Lethality of Scorpion Venom.

Hemiscorpius lepturus (H. lepturus) which belongs to the Scorpionidae family, is the deadliest scorpion in Iran. It causes pathological manifestations like dermonecrosis, hemolysis, renal failure, necrotic ulcers, and in some cases, even death. The venom of this scorpion is well-known for its cytotoxic effects in comparison with the other venomous scorpions which show significant neurotoxic effects. Due to the painless nature of the sting of this scorpion, the clinical symptoms occur in victims 24 to 72 h post-sting. In our previous studies during the last decade, we demonstrated that the medical complications are attributable to the presence of phospholipase D (PLD) as a major toxin in the venom. With the purpose of designing and constructing a vaccine against H. lepturus for humans, animal model experiments were performed. To achieve this goal, non-toxic PLD was developed by mutation of two critical catalytic residues-His12 and His48-into alanines and the product was then denominated mut-rPLD1. The in-vivo tests showed that the mice immunized with interval doses of 10 µg of mut-rPLD1, were completely protected against 10× the LD100 of the venom. In conclusion, this mutant may be an effective vaccine candidate against scorpion envenomation by H. lepturus in future clinical studies.

The Immune Activity of PT-Peptide Derived from Anti-Lipopolysaccharide Factor of the Swimming Crab Portunus trituberculatus Is Enhanced when Encapsulated in Milk-Derived Extracellular Vesicles.

PT-peptide is derived from the anti-lipopolysaccharide factor of the swimming crab Portunus trituberculatus. The peptide, consisting of 34 amino acids, contains a lipopolysaccharide binding domain. In this study, we investigated the effect of PT-peptide encapsulated in raw milk-derived extracellular vesicles (EVs), designated as EVs-PT peptide, on immune regulation. The results showed that raw milk-derived EVs efficaciously delivered the PT-peptide into monocytes and elevated immune activity, including reactive oxygen species level, superoxide anion production, and phagocytosis. PT-peptide and EVs-PT peptide also elevated the secretion of cytokines, such as interferon-γ, interleukin-6, and tumor necrosis factor-α in human monocytic THP-1 cells. These results suggest that the PT-peptide could be developed as an immune stimulator.

Subcutaneous immunotherapy with purified Der p1 and 2 suppresses type 2 immunity in a murine asthma model.

BACKGROUND: Allergen-specific immunotherapy can induce long-term suppression of allergic symptoms, reduce medication use, and prevent exacerbations of allergic rhinitis and asthma. Current treatment is based on crude allergen extracts, which contain immunostimulatory components such as ß-glucans, chitins, and endotoxin. Use of purified or recombinant allergens might therefore increase efficacy of treatment. AIMS: Here, we test application of purified natural group 1 and 2 allergens from Dermatophagoides pteronyssinus (Der p) for subcutaneous immunotherapy (SCIT) treatment in a house dust mite (HDM)-driven mouse model of allergic asthma. MATERIALS AND METHODS: HDM-sensitized mice received SCIT with crude HDM extract, a mixture of purified Der p1 and 2 (DerP1/2), or placebo. Upon challenges, we measured specific immunoglobulin responses, allergen-induced ear swelling response (ESR), airway hyperresponsiveness (AHR), and inflammation in bronchoalveolar lavage fluid (BAL) and lung tissue. RESULTS: ESR measurement shows suppression of early allergic response in HDM-SCIT- and DerP1/2-SCIT-treated mice. Both HDM-SCIT and DerP1/2-SCIT are able to suppress AHR and eosinophilic inflammation. In contrast, only DerP1/2-SCIT is able to significantly suppress type 2 cytokines in lung tissue and BAL fluid. Moreover, DerP1/2-SCIT treatment is uniquely able suppress CCL20 and showed a trend toward suppression of IL-33, CCL17 and eotaxin levels in lung tissue. DISCUSSION: Taken together, these data show that purified DerP1/2-SCIT is able to not only suppress AHR and inflammation, but also has superior activity toward suppression of Th2 cells and HDM-induced activation of lung structural cells including airway epithelium. CONCLUSIONS: We postulate that treatment with purified natural major allergens derived from HDM will likely increase clinical efficacy of SCIT.

Long-term effects of adenotonsillectomy on serum-specific immunoglobulin E.

BackgroundThe biased immune reactions of the adenotonsillar tissues are not always reflected by the serum immunoglobulin E (IgE); thus, we hypothesize that the systemic atopic status may not be changed after the adenotonsillectomy (AT) in children.MethodsTwenty-five children with AT and 23 age-matched healthy children were enrolled into this study, and followed up for ~4 years. Nasal Symptoms Scores (NSS), Quality of Life Scores (QOLS), specific IgE (sIgE), cytokines, and inflammatory cell were documented in all the subjects before and after study.ResultsFourteen patients and three healthy controls had positive serum sIgE levels (>0.35 kU/l) at the study-start that was not changed by the study-end. Two patients and two sIgE-negative healthy controls showed the Dermatophagoidespteronyssinus sensitization at the study-end. NSS and QOLS showed significant improvement after the surgery in the sIgE-positive patients (P<0.05), whereas no significant changes were found in the sIgE-negative patients (P=1.00). In addition, the serum sIgE-negative patients showed significant increases in interleukin (IL)-4, IL-5, and IL-10 levels in the serum (P<0.001), although no significant differences were found post surgery (P=0.667, 0.408, and 0.714, respectively).ConclusionsOur study showed that AT did not affect the pediatric atopic status. The systemic atopy may be independent of the tonsillar and adenoid tissues in children.

Proof of concept of the preventive efficacy of high-dose recombinant mono-allergen immunotherapy in atopic dogs sensitized to the Dermatophagoides farinae allergen Der f 2.

BACKGROUND: Allergen immunotherapy is currently the only intervention proposed to specifically prevent clinical flares after allergen challenges. The low molecular weight Der f 2 (Df2) is a major allergen in Japanese dogs sensitized to Dermatophagoides farinae house dust mites. OBJECTIVES: Pilot, blinded, placebo-controlled experiment testing the efficacy of subcutaneous immunotherapy (SCIT) with high doses of recombinant Df2 conjugated to the maltotriose pullulan (rDf2-P). METHODS: Eight Maltese beagle atopic dogs were sensitized to rDf2 then randomized to SCIT with rDf2-P (six dogs) or placebo (two). The immunotherapy consisted of six weekly injections of increasing doses (0.1-10.0 µg) of rDf2-P followed by four monthly injections of 10 µg of this allergen. Epicutaneous rDf2 challenges, rDf2-specific IgE serology and intradermal reactivity, as well as serum cytokine level measurements, were performed throughout the study. RESULTS: Subcutaneous injections of placebo did not alter the cutaneous reactivity after rDf2 challenge, while that of the dogs treated with rDf2-P SCIT disappeared in five of six dogs (83%) and was reduced in one of six (17%). During SCIT maintenance, skin lesion scores were significantly lower in dogs receiving SCIT compared to those treated with placebo. This clinical improvement was accompanied by a concurrent, yet not significant, decrease in rDf2-specific IgE serology and immediate intradermal reactivity. Cytokine serum levels were inconclusive. There were no adverse events seen with rDf2-P SCIT. CONCLUSIONS AND CLINICAL IMPORTANCE: The new mono-allergen SCIT appears safe and effective for reducing skin lesions after allergen challenges; it deserves further testing in dogs with spontaneous atopic dermatitis.

Looped limulus anti-lipopolysaccharide derived peptide CLP-19 induces endotoxin tolerance involved inhibition of NF-κB activation.

Endotoxin tolerance (ET) is a complex protective mechanism against endotoxin shock. The looped CLP-19 peptide derived from Limulus anti-LPS peptide induced the ET phenomenon but the molecular mechanism has yet to be fully elucidated. Here, we confirmed that CLP-19 attenuated upon LPS stimulated pro-inflammatory factor secretion of TNF-α and IL-6 but increased anti-inflammatory factor production of IL-10 in dose- and time-dependent manners. CLP-19 also inhibited subsequent LPS stimulated expression of TLR4 on the cell membrane. Moreover, the CLP-19 inhibited degradation of the inhibitor of NF-κB (IκBα and IκBß) and reduced LPS induced NF-κB activity, but not of effects on expression of MyD88 and TRAF-6. Finally CLP-19 significantly increased survival of lethal LPS shock mouse models with significantly less pathological injury to lung. These findings collectively suggest that CLP-19 induces ET phenomenon involved inhibition of NF-κB activation. In conclusion, this study has revealed a novel function of CLP-19 that appears to represent a potential therapeutic agent for clinical treatment of septic shock.

Suppression of dust mite allergy by mucosal delivery of a hypoallergenic derivative in a mouse model.

Allergic asthma caused by house dust mite (HDM) is becoming a public health problem. Specific immunotherapy is considered to be the only curative treatment, but it is always associated with IgE-mediated side effects in the therapy process. A few studies showed that the disruption of allergen IgE epitopes could reduce IgE reactivity and thus reduce allergenic activity. In this study, a hypoallergenic derivative of the major HDM allergen Der p2 was constructed by genetic engineering. This derivative was confirmed to have a considerably reduced IgE reactivity compared with Der p2. For its application in vivo, recombinant Lactococcus lactis (LL-DM) was engineered to deliver the Der p2 derivative to the intestinal mucosal surface. Oral administration of LL-DM significantly alleviated Der p2-induced airway inflammation, as shown by reduced inflammatory infiltration and a reduction in Th2 cytokines in bronchoalveolar lavage. This protective effect was associated with an up-regulation of specific IgG2a and a decrease in IL-4 level in the spleen which may affect specific IgE response. Moreover, the levels of regulatory T cells in the mesenteric lymph nodes and spleen were markedly increased in mice fed with LL-DM, suggesting that LL-DM can inhibit allergic responses via the induction of regulatory T cell. Our results indicate that the Der p2 derivative is a promising therapeutic molecule for specific immunotherapy and recombinant lactic acid bacteria could be developed as a promising treatment or prevention strategy for allergic diseases.

Vitamin D as an adjunct to subcutaneous allergen immunotherapy in asthmatic children sensitized to house dust mite.

BACKGROUND: We aimed to investigate the efficacy, safety, and T regulatory cell response of vitamin D as an adjunct to allergen-specific immunotherapy (IT). METHODS: Fifty children with asthma and receiving pharmacotherapy were randomized into three groups as: subcutaneous IT (SCIT) along with vitamin D supplementation (650 U/day; n: 17), SCIT alone (n: 15), and pharmacotherapy alone (n: 18). All patients were evaluated at baseline, 6th and 12th months for scorings of symptoms and medication, skin prick testing, total IgE, specific IgE, and Der p 1-specific IgG4. In addition, D. pteronyssinus-induced CD4(+) CD25(+) FOXP3(+) T regulatory cell percentage, intracellular Foxp3 expression, and peripheral blood mononuclear cell IL-10 and TGF-ß responses were assessed. RESULTS: In the SCIT + vitamin D and SCIT alone groups, total asthma symptom score (TASS), total symptom score (TSS), and total medication scores (TMS) were significantly lower than pharmacotherapy group at the end of 1 year. While the comparison of delta values (Δ 6th and Δ 12th month - baseline) of those scores revealed no significant differences between the two IT groups, TASS at the 6th month was lower in the SCIT + vitamin D group compared with others. There was a significant and positive trend in the levels of Der p 1-specific IgG4 in both IT groups throughout the study period. Whereas the levels of Der p 1-induced IL-10 and TGF-ß were similar between IT groups, the mean fluorescence intensity of Foxp3 was highest in the SCIT + vitamin D group compared with others at the 12th month. The rate of discontinuation of inhaled corticosteroid (ICS) was 6/17 in SCIT + vitamin D, 3/15 in SCIT, and 0/18 in the pharmacotherapy group (P = 0.02). CONCLUSION: Both SCIT groups fared better than pharmacotherapy alone at the end of 1 year. Although the clinical and immunologic outcomes were mostly similar between the two IT groups, some favorable outcomes of vitamin D warrant further investigation in more selected populations with varying doses as adjunct to IT.

Epicutaneously applied Der p 2 induces a strong TH 2-biased antibody response in C57BL/6 mice, independent of functional TLR4.

BACKGROUND: The major house dust mite allergen Der p 2 is a structural and functional homologue of MD-2 within the TLR4-CD14-MD-2 complex. An asthma mouse model in TLR4-deficient mice recently suggested that the allergic immune response against Der p 2 is solely dependent on TLR4 signaling. We investigated whether similar mechanisms are important for Der p 2 sensitization via the skin. METHODS: In an epicutaneous sensitization model, the response to recombinant Der p 2 in combination with or without lipopolysaccharide (LPS) was compared between C57BL/6 WT and TLR4-deficient mice. We further analyzed possible adjuvant function of exogenous cysteine proteases. RESULTS: Sensitization with rDer p 2 induced similar levels of allergen-specific IgG1 and IgE antibodies in both mouse strains. LPS increased the systemic (antibody levels, cytokine release by restimulated splenocytes) and local (infiltration of immune cells into the skin) Th2 immune responses, which against our expectations were stronger in the absence of functional TLR4 expression. Barrier disruption by papain, a protease with structural homology to Der p 1, did not enhance the sensitization capacity of rDer p 2. However, the presence of LPS increased the stability of rDer p 2 against the protease. CONCLUSION: Our data suggest that rDer p 2 alone can cause a strong TH 2-biased response via the skin being enhanced in the presence of LPS. This response is not reliant on functional TLR4, but vice versa TLR4 expression rather protects against epicutaneous sensitization to house dust mite allergen Der p 2.

Expression and characterization of natural-like recombinant Der p 2 for sublingual immunotherapy.

BACKGROUND: Recombinant allergens with a native conformation represent an alternative to natural extracts for immunotherapy and diagnostic purposes. METHODS: We produced the Der p 2 mite allergen in Pichia pastoris and Escherichia coli. After purification by cation exchange chromatography, recombinant molecules were compared to their natural counterpart based upon structural (disulfide bonds, secondary structure, thermal stability) and immunological properties (antibody reactivity, basophil and T cell activation, tolerance induction in a murine sublingual immunotherapy model). RESULTS: The Der p 2.0101 isoform was confirmed to be prevalent in Dermatophagoides pteronyssinus extracts. It was then produced as a secreted molecule in P. pastoris or refolded from E. coli inclusion bodies. The yeast-expressed rDer p 2 molecule exhibits a natural-like disulfide bridge distribution and secondary structure, whereas the E. coli-derived rDer p 2 presents some heterogeneity in cysteine bonds and a lower stability following thermal stress. The two recombinant as well as natural Der p 2 molecules exhibit comparable IgE recognition and activate basophil and CD4+ T cells. Sublingual immunotherapy of nDer p 2- sensitized mice using either one of the rDer p 2 molecules efficiently decreases airway hyperresponsiveness as well as Th2 responses. CONCLUSIONS: Natural and recombinant Der p 2 molecules produced in P. pastoris and E. coli exhibit comparable immunological properties despite distinct structural features. Natural-like cysteine pairing is a critical parameter to identify stable, well-folded and homogenous proteins appropriate for immunotherapy and diagnostic purposes.

Evaluation of sensitization to the crude extract of Dermatophagoides farinae and its derived allergens, Der f 2 and Zen 1, in dogs with atopic dermatitis in Southern Brazil.

BACKGROUND: Atopic dermatitis is associated with the production of IgE antibodies against environmental allergens and allergens of the house dust miteDermatophagoides farinae are frequently implicated in the disease. OBJECTIVES: We aimed to observe the allergen-specific IgE against crudeD. farinae, Der f 2 and Zen 1 in dogs with atopic dermatitis and report if these dogs are in contact with material that could shelter mite allergens. METHODS: 100 dogs with clinical diagnosis of atopic dermatitis were included after exclusion of other forms of pruritic skin disease and dogs that already received specific or non-specific immunotherapy. These dogs were of different breeds and ages and they were presented at a veterinary teaching hospital and a private service of veterinary dermatology, both located in Curitiba, Southern Brazil. At the time of anamnesis, some questions were applied to know the possibility of these dogs having had contact with furniture and textile material which could shelter house dust mites. Sera samples were obtained and further analyzed by ELISA assay to measure serum IgE levels against these allergens with an established cut-off of 0.200 IgE optical density. RESULTS: The allergen-specific IgE positivity against crudeD. farinae (92 %) and Zen 1 (77 %) was higher than Der f 2 (56 %). There was a correlation in sensitization to crude D. farinae and Zen 1 that was not observed between crude D. farinae and Der f 2 and Der f 2 and Zen 1. The sensitization to D. farinae and its allergens was associated with an unrestricted exposition to furniture and textile material. CONCLUSION & CLINICAL RELEVANCE: dogs with atopic dermatitis are frequently sensitized to D. farinae and its allergens, Der f 2 and Zen 1, may be considered major allergens in these dogs. Zen 1 may be the main allergen responsible for the sensitization to crude D. farinae.