Reduction of Antigenicity of Cry j I, Major Allergen of Japanese Cedar Pollen, by the Attachment of Polysaccharides

One-pot preparation of mannan-coated antigen nanoparticles using human serum albumin as a matrix for tolerance induction

Nanoparticles (NPs) for allergen immunotherapy have garnered attention for their high efficiency and safety compared with naked antigen proteins. In this work, we present mannan-coated protein NPs, incorporating antigen proteins for antigen-specific tolerance induction. The heat-induced formation of protein NPs is a one-pot preparation method and can be applied to various proteins. Here, the NPs were formed spontaneously via heat denaturation of three component proteins: an antigen protein, human serum albumin (HSA) as a matrix protein, and mannoprotein (MAN) as a targeting ligand for dendritic cells (DCs). HSA is non-immunogenic, therefore suitable as a matrix protein, while MAN coats the surface of the NP. We applied this method to various antigen proteins and found that the self-disperse after heat denaturation was a requirement for incorporation into the NPs. We also established that the NPs could target DCs, and the incorporation of rapamycin into the NPs enhanced the induction of a tolerogenic phenotype of DC. The MAN coating provided steric hindrance and heat denaturation destroyed recognition structures, successfully preventing anti-antigen antibody binding, indicating the NPs may avoid anaphylaxis induction. The MAN-coated NPs proposed here, prepared by a simple method, have the potential for effective and safe allergies treatment for various antigens.

Reduced anaphylactic potential of denatured pullulan-conjugated Cry j 1

Japanese Cedar (JC) pollinosis is the most common seasonal allergic rhinitis in Japan. Throughout the JC pollen season, patients suffer from the allergic symptoms, resulting in a reduction of quality of life. Allergy immunotherapy (AIT) is an established treatment option for a wide range of allergens that unlike symptomatic treatments (e.g. antihistamines) may provide sustained immune tolerance. However, AIT, especially subcutaneous immunotherapy (SCIT) has a fatal anaphylaxis risk due to the use of crude allergen extracts. Consequently, development of allergen derivatives with substantially reduced anaphylactic potential is desirable. An allergen derivative that showed reduced IgE-binding and anaphylactic potential was developed through conjugation of native Cry j 1 (n Cry j 1), a major JC allergen, to the polysaccharide pullulan followed by chemical but non-covalent denaturation. The resulting Cry j 1 allergen derivative, Dn p-Cry j 1, showed reduced IgE-binding and IgE-mediated effector cell activation in vitro using an ELISA competition assay and a mast cell activation model (EXiLE). Reduced anaphylactic potential of Dn p-Cry j 1 in vivo was demonstrated using the rat passive cutaneous anaphylaxis (PCA) assay. The difference in anaphylactic potential of Dn p-Cry j 1 compared to n Cry j 1 in wild-type rats was of the same magnitude as the difference seen in the anaphylaxis reactions obtained with n Cry j 1 in wild-type rats and mast-cell deficient rats, indicating a dramatic reduction in anaphylactic potential of Dn p-Cry j 1. These results indicate that Dn p-Cry j 1 is a promising candidate for next-generation JC AIT.

Solid-in-Oil Nanodispersions for Transcutaneous Immunotherapy of Japanese Cedar Pollinosis

Japanese cedar pollinosis (JCP) is a common affliction caused by an allergic reaction to cedar pollen and is considered a disease of national importance in Japan. Antigen-specific immunotherapy (AIT) is the only available curative treatment for JCP. However, low compliance and persistence have been reported among patients subcutaneously or sublingually administered AIT comprising a conventional antigen derived from a pollen extract. To address these issues, many research studies have focused on developing a safer, simpler, and more effective AIT for JCP. Here, we review the novel antigens that have been developed for JCP AIT, discuss their different administration routes, and present the effects of anti-allergy treatment. Then, we describe a new form of AIT called transcutaneous immunotherapy (TCIT) and its solid-in-oil (S/O) nanodispersion formulation, which is a promising antigen delivery system. Finally, we discuss the applications of S/O nanodispersions for JCP TCIT. In this context, we predict that TCIT delivery by using a S/O nanodispersion loaded with novel antigens may offer an easier, safer, and more effective treatment option for JCP patients.

Transcutaneous Delivery of Immunomodulating Pollen Extract-Galactomannan Conjugate by Solid-in-Oil Nanodispersions for Pollinosis Immunotherapy

Japanese cedar pollinosis is a type I allergic disease and has already become a major public health problem in Japan. Conventional subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) cannot meet patients' needs owing to the side effects caused by both the use of conventional whole antigen molecules in the pollen extract and the administration routes. To address these issues, a surface-modified antigen and transcutaneous administration route are introduced in this research. First, the pollen extract (PE) was conjugated to galactomannan (PE-GM) to mask immunoglobulin E (IgE)-binding epitopes in the PE to avoid side effects. Second, as a safer alternative to SCIT and SLIT, transcutaneous immunotherapy (TCIT) with a solid-in-oil (S/O) nanodispersion system carrying PE-GM was proposed. Hydrophilic PE-GM was efficiently delivered through mouse skin using S/O nanodispersions, reducing the antibody secretion and modifying the type 1 T helper (Th1)/ type 2 T helper (Th2) balance in the mouse model, thereby demonstrating the potential to alleviate Japanese cedar pollinosis.

Next generation immunotherapy for tree pollen allergies

Tree pollen induced allergies are one of the major medical and public health burdens in the industrialized world. Allergen-Specific Immunotherapy (AIT) through subcutaneous injection or sublingual delivery is the only approved therapy with curative potential to pollen induced allergies. AIT often is associated with severe side effects and requires long-term treatment. Safer, more effective and convenient allergen specific immunotherapies remain an unmet need. In this review article, we discuss the current progress in applying protein and peptide-based approaches and DNA vaccines to the clinical challenges posed by tree pollen allergies through the lens of preclinical animal models and clinical trials, with an emphasis on the birch and Japanese red cedar pollen induced allergies.

Safety and efficacy of short-term oral immunotherapy with Cry j 1-galactomannan conjugate for Japanese cedar pollinosis: a randomized controlled trial

Current allergen-specific immunotherapy (AIT) for pollinosis requires long-term treatment with potentially severe side effects. Therefore, development of an AIT that is safe and more convenient with a shorter regimen is needed. This prospective, double-blind, placebo-controlled trial randomized 55 participants with Japanese cedar pollinosis (JCP) to active or placebo groups to test the safety and efficacy of short-term oral immunotherapy (OIT) with Cry j 1-galactomannan conjugate for JCP. Mean symptom-medication score as the primary outcome in the active group improved 27.8% relative to the placebo group during the entire pollen season. As the secondary outcomes, mean medication score in active group improved significantly, by 56.2%, compared with placebo during the entire pollen season. Mean total symptom score was similar between active and placebo groups during the entire pollen season. There were no severe treatment-emergent adverse events in the active and placebo groups. Therefore short-term OIT with Cry j 1-galactomannan conjugate is safe, and effective for reducing the amount of medication use for JCP.

Effect of short-term oral immunotherapy with Cry j1-galactomannan conjugate on quality of life in Japanese cedar pollinosis patients: A prospective, randomized, open-label study

OBJECTIVE

We have recently reported that a new regimen of short-term oral immunotherapy (OIT) with the Cry j1-galactomannan conjugate for Japanese cedar pollinosis (JCP) is effective to the improvement in the symptoms and medication use during the pollen season and relatively safe. The effect of OIT on quality of life (QOL) of JCP patients has not been assessed. Therefore, we evaluated for the first time the effect of OIT on QOL during the Japanese cedar/cypress pollen season.

METHODS

A prospective, randomized, open-label trial was conducted over a period of 4 months. Participants were randomly divided into two groups. The OIT and control groups comprised 23 and 24 subjects, respectively. The build-up phase was initiated 1 month before the expected pollen season. The maintenance phase was continued for 51 days during the peak of the cedar pollen season. The QOL score in the Japan Rhinoconjunctivitis Quality of Life Questionnaire (JRQLQ) No. 1 and visual analog scale (VAS) throughout the pollen season were evaluated.

RESULTS

Participants receiving OIT showed significant improvements in the total QOL score and VAS throughout the pollen season compared with the control group. In addition, the mean total QOL score and VAS correlated in both groups during the pollen season.

CONCLUSION

The new regimen of short-term OIT using the Cry j1-galactomannan conjugate results in meaningful improvements in QOL of JCP patients. Our findings suggest that short-term OIT using allergen-galactomannan conjugates, as well as sublingual and subcutaneous immunotherapy, improves QOL of patients with pollinosis. The study was registered in UMIN-CTR (UMIN000013408) as the name of "a prospective, randomized, open study of oral Cry j1-galactomannan conjugate immunotherapy for Japanese cedar pollen allergy".

Safety and efficacy of a new regimen of short-term oral immunotherapy with Cry j 1-galactomannan conjugate for Japanese cedar pollinosis: a prospective, randomized, open-label study

BACKGROUND

Short-term oral immunotherapy (OIT) using the Cry j1-galactomannan conjugate for Japanese cedar pollinosis may be effective and relatively safe. However, a treatment regimen has not been established. In the present study, we examined a new OIT regimen with a build-up phase and extended the maintenance phase of OIT to the peak period of the pollen season to enhance the therapeutic effect and safety of OIT.

METHODS

A prospective, randomized, open-label trial was conducted over a period of 4 months. Participants were randomly divided into two groups. The OIT group comprised 23 subjects. The build-up phase was initiated 1 month before the expected pollen season. The maintenance phase was continued for 51 days during the peak pollen season. The control group comprised 24 subjects. The symptoms and medication score, levels of allergen-specific serum antibodies throughout the pollen season, and adverse effects with OIT were evaluated.

RESULTS

Participants receiving OIT showed significant improvements in total symptom scores, medication score, and total symptom-medication scores throughout the pollen season compared with the control group. The levels of allergen-specific serum IgG4 were significantly increased in the OIT group but not in the control group throughout the cedar pollen season. Importantly, no severe adverse effects were observed with OIT.

CONCLUSIONS

The new regimen of short-term OIT using the Cry j1-galactomannan conjugate for Japanese cedar pollinosis is effective, relatively safe and induces immune tolerance. Thus, OIT using allergen-galactomannan conjugates may provide a rapid, effective, and thus convenient immunotherapy for pollinosis instead of SLIT or SCIT.

Phase I/II study of oral immunotherapy with Cry j1-galactomannan conjugate for Japanese cedar pollinosis

OBJECTIVE

Among many immunotherapeutic approaches, oral immunotherapy (OIT) is thought to be an effective route for desensitization against a variety of allergens. However, there is little evidence that OIT is effective for airway allergic diseases such as pollen allergy. Thus, in the present study, we assessed the safety, efficacy and immune response of OIT using the Cry j1-galactomannan conjugate for Japanese cedar pollen allergy.

METHODS

An open trial was conducted over a period of 4 months. The OIT group comprised of 23 subjects. Treatment was initiated 1 month before the estimated pollen season and continued for 1 month. The control group (the pharmacological treatment group without OIT) comprised of 11 subjects. The symptoms and medication score, levels of allergen-specific serum antibodies, cellular components of lymphocytes and cytokine production from peripheral blood mononuclear cells (PBMCs) were evaluated throughout the pollen season.

RESULTS

The participants receiving OIT treatment showed significant improvements in total symptom scores and symptom-medication scores during the pollen season compared with the control group. The levels of allergen-specific serum IgG4 and IL-10 production in PBMCs were significantly increased in the OIT group compared with that in the control group. Importantly, no severe adverse effects were observed in the participants receiving OIT treatment.

CONCLUSION

Short-term OIT using the Cry j1-galactomannan conjugate is effective, relatively safe and induces tolerant immune responses such as increased allergen-specific serum IgG4 and IL-10 production in PBMCs. These results suggest that OIT using allergen-galactomannan conjugates may provide a rapid, effective, and safe immunotherapy regimen for cedar pollen allergy.

Reduction of the number of major representative allergens: from clinical testing to 3-dimensional structures

Vast amounts of allergen sequence data have been accumulated, thus complicating the identification of specific allergenic proteins when performing diagnostic allergy tests and immunotherapy. This study aims to rank the importance/potency of the allergens so as to logically reduce the number of allergens and/or allergenic sources. Meta-analysis of 62 allergenic sources used for intradermal testing on 3,335 allergic patients demonstrated that in southern China, mite, sesame, spiny amaranth, Pseudomonas aeruginosa, and house dust account for 88.0% to 100% of the observed positive reactions to the 62 types of allergenic sources tested. The Kolmogorov-Smironov Test results of the website-obtained allergen data and allergen family featured peptides suggested that allergen research in laboratories worldwide has been conducted in parallel on many of the same species. The major allergens were reduced to 21 representative allergens, which were further divided into seven structural classes, each of which contains similar structural components. This study therefore has condensed numerous allergenic sources and major allergens into fewer major representative ones, thus allowing for the use of a smaller number of allergens when conducting comprehensive allergen testing and immunotherapy treatments.

Effects of ovalbumin glycoconjugates on alleviation of orally induced egg allergy in mice via dendritic-cell maturation and T-cell activation

SCOPE

Glycation of allergens via Maillard reaction or chemical conjugation has been shown to influence susceptibility to food-induced allergies. It is hypothesized that mucosal immune response bias can be favorably altered by orally administering various forms of glycated ovalbumin (OVA).

METHODS AND RESULTS

Groups of Balb/c mice (n = 10) were orally sensitized to OVA and administered various forms of glycated OVA (glucose, mannose, glucomannan, galactomannan, and a mixture containing OVA and glucomannan). Outcomes post oral challenge were measured as clinical allergic signs, serum histamine, mouse mast cell protease 1 (MMCP-1), antibody activity, type-1/2 cytokines, percentage of T-regulatory cells (T-regs) and in vitro dendritic cell, and T-cell-related mechanisms. Clinical signs and specific IgE were decreased (p ≤ 0.05), and T-reg cell percentage was increased in the mannose and glucomannan treated groups. The OVA-mannose group also had less histamine, MMCP-1, specific IgG, IL-4 and IL-17, and more IL-12p70 (p ≤ 0.05). Other parameters measured did not differ significantly among groups. Also, OVA-glycated mannose reduced maturation and uptake by dendritic cells. Less activation of T cells and type-2 cytokine response in DC-T-cell cocultures were observed with OVA-glycated mannose stimulation.

CONCLUSION

This study validates, for the first time, the use of OVA-glycated mannose and glucomannan for potential beneficial dietary interventions for allergy.

Effects of various saccharides on the masking of epitope sites and uptake in the gut of cedar allergen Cry j 1-saccharide conjugates by a naturally occurring Maillard reaction

A major allergen of Japanese cedar, Cry j 1, was conjugated with galactomannan (M(w) of 15 kDa), dextran (M(w) of 12 kDa), xyloglucan (M(w) of 1.4 kDa), and various monosaccharides through the Maillard reaction by dry-heating in 65% relative humidity. The Cry j 1-galactomannan conjugate completely masked the epitopes of the allergen in Cry j 1. The Cry j 1-dextran conjugate also masked the epitopes of Cry j 1. The small size of oligosaccharide (xyloglucan) and various monosaccharides cannot mask the epitopes of allergen Cry j 1. This suggests that the higher molecular size of attached saccharides is important to mask sterically the epitope sites. The Cry j 1-galactomannan and Cry j 1-mannose conjugates were effectively trafficked in the gut and co-localized with immune cells, such as dendritic cells in the gut, suggesting that Cry j 1-saccharide conjugates are phagocytosed via the mannose receptor in immune cells. These results suggest that the Cry j 1-galactomannan conjugate is suitable for masking the epitope sites of Cry j 1 and trafficking to immune cells in gut lumen.

Reduction of antigenicity of Cry j 1, a major allergen of Japanese cedar pollen, by thermal denaturation

The soluble aggregates of Cry j 1, a major allergen of Japanese cedar pollen, were formed without any coagulates during heat treatment at acidic pH 5, as shown in HPLC and SDS-PAGE patterns. A remarkable change in the CD spectrum was observed between native and heat-denatured Cry j 1 at a linear rate of 1 degrees C/min from 40 to 90 degrees C. The negative peak of native Cry j 1 at 222 nm was moved to 218 nm, suggesting the transition of an alpha-helix to beta-structure during heat denaturation. The increase in beta-structure was also observed during heat denaturation by monitoring the fluorescence with Thioflavin T. These results suggest that Cry j 1 forms intermolecular cross-beta-structure between denatured proteins during heating at 90 degrees C. The antigenicity of Cry j 1 detected by dot-blotting was greatly diminished during heating at a linear rate of 1 degrees C/min from 40 to 90 degrees C without any coagulates. These results suggest that IgE epitopes exposed on the molecular surface of Cry j 1 was buried inside soluble aggregates through intermolecular beta-structure formed by heating.

Design of tomato fruits with reduced allergenicity by dsRNAi-mediated inhibition of ns-LTP (Lyc e 3) expression

Plant genetic engineering has the potential to introduce new allergenic proteins into foods but, at the same time, it can be used to remove established allergens. Here, we report the molecular characterization of Lyc e 3, a new tomato (Lycopersicon esculentum) allergen, and the efficient down-regulation of its expression in transgenic tomato plants. Following the identification of an immunoglobulin E (IgE)-binding 9-kDa polypeptide in tomato peel, designated Lyc e 3, its partial amino acid sequence was determined by N-terminal protein sequencing. Sequence comparison revealed that Lyc e 3 encodes a nonspecific lipid transfer protein (ns-LTP). In plants, ns-LTPs are encoded by large gene families which differ in primary amino acid sequence, expression and proposed cellular function. To identify Lyc e 3 encoding complementary DNAs (cDNAs), public tomato expressed sequence tag (EST) databases were screened for ns-LTP sequences. Following this strategy, two cDNAs, LTPG1 and LTPG2, with high homology to the N-terminal sequence of Lyc e 3, were identified. Ectopic expression of LTPG1 and LTPG2 in Escherichia coli, followed by immunoblotting, verified their IgE reactivity. Subsequently, transgenic tomato plants constitutively expressing LTPG1- or LTPG2-specific double-stranded RNA interference (dsRNAi) constructs were created and tested for the suppression of Lyc e 3 accumulation. Efficient silencing of Lyc e 3 was documented by Northern and Western blotting. In both cases, Lyc e 3 accumulation was decreased to levels below the detection limit (less than 0.5% of the wild-type protein). The allergenic potential of Lyc e 3-deficient tomato fruits was tested by measuring histamine release from sensitized human basophils stimulated with transgenic and parental lines. These assays revealed a strong (10- to 100-fold) decrease in histamine release of human basophils challenged with transgenic fruit extracts when compared with control extracts. These results demonstrate the feasibility of creating low allergenic tomato fruits by means of dsRNAi inhibition.

Engineered allergens for immunotherapy

PURPOSE OF REVIEW

Specific immunotherapy is a clinically effective causative treatment for allergic conditions. However, the reagents used for immunotherapy are crude extracts prepared from natural sources with potential life-threatening anaphylactic side effects. Molecular cloning of allergens has made it feasible to design novel therapeutic approaches for improved and safer forms of allergen-specific immunotherapy. The purpose of this review is to examine recent advances made in the last 2 years in genetic engineering of allergens for specific immunotherapy.

RECENT FINDINGS

Genetic engineering of allergen with nil or low IgE reactivity but retained T-cell reactivity offers a novel therapeutic approach to improving safety and efficacy of allergen-specific immunotherapy. Hypoallergenic forms of major allergens have been produced, with reduced IgE epitopes while preserving other characteristics of the molecule to induce a protective response.

SUMMARY

Hypoallergenic forms of major allergens are potential candidates for allergen-specific immunotherapy in the future. These genetically engineered hypoallergens now need to be tested in clinical trials before being widely used. Safer and more efficacious vaccines would increase patient compliance leading to extensive use of immunotherapy.

Effective reduction of antigenicity of hen egg lysozyme by site-specific glycosylation

Various mutant lysozymes were constructed by genetic modification and secreted in yeast expression system to evaluate the changes in the antigenicity of hen egg lysozyme (HEL). Although Arg68, the most critical residue to antigenicity of HEL, was substituted with Gln, the binding of monoclonal antibodies (mAbs) with the mutant lysozyme did not critically reduce, remaining 60% of the binding with mAb. In contrast, glycosylated mutant lysozyme G49N whose glycine was substituted with asparagine dramatically reduced the binding with mAb. The oligomannosyl type of G49N lysozyme reduced binding with mAb to one-fifth, while the polymannosyl type of G49N lysozyme completely diminished the binding with mAb. This suggests that the site-specific glycosylation of lysozyme in the interfacial region of lysozyme-antibody complex is more effective to reduce the antigenicity than the mutation of single amino acid substitution in the interfacial region.