Identification of a polygalacturonase (Cup s 2) as the major CCD-bearing allergen in Cupressus sempervirens pollen

Correlation Between N-Glycan GnGnXF3 and the Allergic Immune Response Against Juniperus ashei Pollen

BACKGROUND

Cupressaceae pollen increasingly causes respiratory allergies worldwide. Carbohydrates are abundant in extracts of these pollens, and the associated allergens are highly glycosylated. However, the contribution of saccharides to the allergenicity of these species remains unknown.

METHODS

Juniperus ashei pollen extract was deglycosylated and characterised using SDS-PAGE and immunoblotting. Additionally, N- and O-glycans were purified from the extract, identified, used as inhibitors in IgE-immunoblotting and further analysed via basophil activation tests. The interactions between IgE and J. ashei glycans were analysed using a glycan array. Purified Jun a 1 was treated with β-N-acetylglucosaminidase S and analysed using immunoblotting. The native pollen extract was used to immunise rabbits, and the IgG response was analysed using ELISA and glycan array.

RESULTS

Deglycosylation of J. ashei proteins abolished the interaction between IgE and allergens. This effect primarily depends on N-glycans. Purified N-glycans triggered basophil activation in some patients. A biantennary N-glycan with terminal GlcNAc, β-1,2 xylose and core α-1,3 fucose (GnGnXF3) was the most abundant glycan identified. The glycan array confirmed its interaction with IgE. The contribution of terminal N-acetylglucosamines (GlcNAc) to IgE-Jun a 1 interaction was validated. Moreover, effective immunisation of rabbits with the native extract confirmed the immunogenicity of their N-glycans.

CONCLUSIONS

The IgE-J. ashei allergen interaction is broadly controlled through N-glycans different from MUXF3. GnGnXF3 exerts an immunogenic effect in humans and rabbits; terminal GlcNAc residues influence its recognition by IgE. These discoveries reinforce the role of N-glycans in the allergic response to J. ashei.

Structural Basis for the IgE-Binding Cross-Reacting Epitopic Peptides of Cup s 3, a PR-5 Thaumatin-like Protein Allergen from Common Cypress (Cupressus sempervirens) Pollen

The present work was aimed at identifying the IgE-binding epitopic regions on the surface of the Cup s 3 allergen from the common cypress Cupressus sempervirens, that are possibly involved in the IgE-binding cross-reactivity reported between Cupressaceae species. Three main IgE-binding epitopic regions were mapped on the molecular surface of Cup s 3, the PR-5 thaumatin-like allergen of common cypress Cupressus sempervirens. They correspond to exposed areas containing either electropositive (R, K) or electronegative (D, E) residues. A coalescence occurs between epitopes #1 and #2, that creates an extended IgE-binding regions on the surface of the allergen. Epitope #3 contains a putative N-glycosylation site which is actually glycosylated and could therefore comprise a glycotope. However, most of the allergenic potency of Cup s 3 depends on non-glycosylated epitopic peptides. The corresponding regions of thaumatin-like allergens from other closely related Cupressaceae (Cryptomeria, Juniperus, Thuja) exhibit a very similar conformation that should account for the IgE-binding cross-reactivity observed among the Cupressaceae allergens.

Update on pollen-food allergy syndrome

INTRODUCTION

Allergies affect 20-30% of the population and respiratory allergies are mostly due to pollen grains from anemophilous plants. One to 5% of people suffer from food allergies and clinicians report increasing numbers of pollen-food allergy syndrome (PFAS), such that the symptoms have broadened from respiratory to gastrointestinal, and even to anaphylactic shock in the presence of cofactors. Thirty to 60% of food allergies are associated with pollen allergy while the percentage of pollen allergies associated to food allergy varies according to local environment and dietary habits.

AREAS COVERED

Articles published in peer-reviewed journals, covered by PubMed databank, clinical data are discussed including symptoms, diagnosis, and management. A chapter emphasizes the role of six well-known allergen families involved in PFAS: PR10 proteins, profilins, lipid transfer proteins, thaumatin-like proteins, isoflavone reductases, and β-1,3 glucanases. The relevance in PFAS of three supplementary allergen families is presented: oleosins, polygalacturonases, and gibberellin-regulated proteins. To support the discussion a few original relevant results were added.

EXPERT OPINION

Both allergenic sources, pollen and food, are submitted to the same stressful environmental changes resulting in an increase of pathogenesis-related proteins in which numerous allergens are found. This might be responsible for the potential increase of PFAS.

Mediterranean Cypress “Cupressus sempervirens”: A Review on Phytochemical and Pharmacological Properties

Background:

Cupressus sempervirens (C. sempervirens), commonly known as Mediterranean cypress is native to the eastern Mediterranean region, North America and subtropical Asia at higher altitudes. The crude, semi-purified and purified extracts of C. sempervirens have long been recognized for its pharmacological activities as evidenced by its extensive use by indigenous cultures in herbal medicines, tonics and infusion. Pharmacological properties displayed the prodigious biological activities that could be further explored for development of new herbal formulations or therapeutic agents.

Aims:

This review presents a critical analysis of the current state of knowledge about the ethno medicinal uses, phytochemistry and pharmacological properties of C. sempervirens L and its future applications.

Materials and Methods:

Literature related to C. sempervirens and its synonyms were searched on the available online literature databases such as Google Scholar, PubMed, SciFinder, Scopus, Springer, ScienceDirect, Wiley, ACS, Scielo and Web of Science, thesis, dissertations, books, reports, local herbal encyclopedias and other relevant websites.

Results:

A review of literature showed that decoction of cones and young branches of C. sempervirens gave astonishing effect in the treatment of hemorrhoids and to treat excessive sweating in the feet. Enormous pharmacological properties have been found including antiseptic, anti-inflammatory, antispasmodic, antioxidant, antimicrobial, hepatoprotective, wound-healing, anticoagulant, antihyperlipidemic, anticancer, neurobiological, antidiabetic, and antiosteoporotic. Approximately 109 phytochemical constituents have been searched out as isolates from various parts of this plant comprising mostly diterpenoids and biflavonoids.

Conclusion:

Numerous in vivo and in vitro studies have provided support for the traditional uses of C. sempervirens but further research work is required towards isolating more active constituents and for validating its clinical utilization in the herbal formulations for humans as well as investigating any potential toxicity for future clinical studies.

Pollen/Fruit Syndrome: Clinical Relevance of the Cypress Pollen Allergenic Gibberellin-Regulated Protein

A pollen/food-associated syndrome (PFAS) has been described between peach and cypress pollen. Cross-reactive allergens were characterized which belong to the Gibberellin-regulated protein (GRP) family, BP14 in cypress pollen and Pru p 7 in peach. GRP are small cationic protein with anti-microbial properties. A patient suffering from a peach/cypress syndrome was explored clinically and biologically using 2 types of immunoglobulin E (IgE) multiarray microchip, immunoblots and a basophil activation test to assess the clinical relevance of various extracts and purified allergens from fruits or cypress pollen. In addition to PR10 sensitization, the patient showed specific IgE to Pru p 7, BP14 and allergen from pomegranate. These last 3 allergens and allergenic sources are able to induce ex vivo basophil activation characterized by the monitoring of the expression of CD63 and CD203c, both cell surface markers correlated with a basophil mediator release. Up to 100% of cells expressed CD203c at 50 ng/mL of BP14 protein. In contrast, snakin-1, a GRP from potato sharing 82% sequence identity with Pru p 7 did not activate patient's basophils. These results strongly suggest that, like Pru p 7, BP14 is a clinically relevant allergenic GRP from pollen. Allergen members of this newly described protein family are good candidates for PFAS where no cross-reactive allergens have been characterized.

Double One-Dimensional Electrophoresis (D1-DE) Adapted for Immunoproteomics

The classical proteomics approach for the identification of allergen candidates consists on the separation of proteins by high-resolution two-dimensional electrophoresis (2-DE) with subsequent IgE immunoblotting and further analysis of IgE-reactive protein spots with mass spectrometry. In this approach at least two gels most be run. One gel is used for staining and the other is for immunoblotting by antibodies labeled with specific immunostains. Additional functional characterizations require either protein purification or 2-DE replicates and appear to be time- and reagent-consuming. Here we described a modified double one-dimensional electrophoresis (D1-DE) allowing the conversion of a protein spot previously visualized by 2-DE into an extended protein band. In D1-DE, the purity of the protein of interest is similar to 2-DE spots, but its abundance is many times higher than what can be found in a 2-DE single spot allowing many other functional analyses from a single D1-DE separation.

Plant food allergy: Influence of chemicals on plant allergens

Plant-derived foods are the most common allergenic sources in adulthood. Owing to the rapidly increasing prevalence of plant food allergies in industrialized countries, the environmental factors are suspected to play a key role in development of allergic sensitization. The present article provides an overview of ways by which chemicals may influence the development and severity of allergic reactions to plant foods, with especial focus on plant allergens up-regulated under chemical stress. In plants, a substantial part of allergens have defense-related function and their expression is highly influenced by environmental stress and diseases. Pathogenesis-related proteins (PR) account for about 25% of plant food allergens and some are responsible for extensive cross-reactions between plant-derived foods, pollen and latex allergens. Chemicals released by anthropogenic sources such as agriculture, industrial activities and traffic-related air pollutants are potential drivers of the increasing sensitization to allergenic PRs by elevating their expression and by altering their immunogenicity through post-translational modifications. In addition, some orally-taken chemicals may act as immune adjuvants or directly trigger non-IgE mediated food allergy. Taken together, the current literature provides an overwhelming body of evidence supporting the fact that plant chemical exposure and chemicals in diet may enhance the allergenic properties of certain plant-derived foods.