Dietary fiber pectin alters the gut microbiota and diminishes the inflammatory immune responses in an experimental peach allergy mouse model.

Since therapeutic options are limited the utilization of prebiotics is suggested to prevent food allergies (FAs). Using an experimental peach allergy model we explored the effect of dietary fiber pectin, a high-methoxyl heteropolysaccharide, on the manifestation of FA. CBA/J mice were sensitized, subsequently orally boosted and provoked with peach peel extract.

Characterization of the Immune-Modulating Properties of Different β-Glucans on Myeloid Dendritic Cells.

In allergen-specific immunotherapy, adjuvants are explored for modulating allergen-specific Th2 immune responses to re-establish clinical tolerance. One promising class of adjuvants are β-glucans, which are naturally derived sugar structures and components of dietary fibers that activate C-type lectin (CLR)-, "Toll"-like receptors (TLRs), and complement receptors (CRs). We characterized the immune-modulating properties of six commercially available β-glucans, using immunological (receptor activation, cytokine secretion, and T cell modulating potential) as well as metabolic parameters (metabolic state) in mouse bone marrow-derived myeloid dendritic cells (mDCs).

Cross-protection of AIT-induced antibodies to related allergens requires a high degree of structural identity.

Background: In contrast to sublingual immunotherapy (SLIT) with recombinant Mal d 1 (rMal d 1-SLIT), SLIT with rBet v 1 (rBet v 1-SLIT) induced Mal d 1-cross-reactive antibodies without IgE-blocking activity. To elucidate whether the development of cross-protective IgG responses depends on the degree of molecular identity of allergens we compared the cross-reactivity, cross-blocking activity, and affinity of SLIT-induced antibodies with allergens of varying amino acid sequence identities to Bet v 1 and Mal d 1, namely Cor a 1.04 (hazelnut), Pru av 1 (cherry), and Dau c 1 (carrot).

IL-10-modulated dendritic cells from birch pollen- and hazelnut-allergic patients facilitate Treg-mediated allergen-specific and cross-reactive tolerance.

Background: Approximately 70% of individuals allergic to birch pollen (Bet v 1.01 [Bet]) develop a secondary food allergy (e.g.

Effects of pectin methyl-esterification on intestinal microbiota and its immunomodulatory properties in naive mice.

Pectins are dietary fibers that are attributed with several beneficial immunomodulatory effects. Depending on the degree of esterification (DE), pectins can be classified as high methoxyl pectin (HMP) or low methoxyl pectin (LMP). The aim of this study was to investigate the effects of pectin methyl-esterification on intestinal microbiota and its immunomodulatory properties in naive mice.

Allergic Reaction to a Commercially Available Insect Snack Caused by House Cricket (Acheta domesticus) Tropomyosin.

Scope: Edible insects contain allergens with potential cross-reactivity to other invertebrates. Here, this study examines IgE-reactive proteins in a house cricket snack (Acheta domesticus) leading to an allergic reaction in a 27-year old man followed by a similar reaction days later after eating shrimps.

Methods And Results: Prick to prick tests verify the IgE-mediated allergy to crickets and skin prick testing confirms a type I sensitization to house dust mite without any clinical relevance for the patient, and to shrimp extracts, but is negative for several other foods.

The Role of IgA in the Manifestation and Prevention of Allergic Immune Responses.

Purpose Of Review: Immunoglobulin A (IgA) mediates immune exclusion of antigens in the gut. Notably, IgA plays also a role in the prevention of IgE-mediated allergies and induction of immune tolerance. The present review addresses the role of IgA in the manifestation of IgE-mediated allergies, including allergen-specific immunotherapy (AIT), the regulation of IgA production, and the mechanism of IgA in immune cell activation.

A flagellin-conjugate protein induces dual NLRC4- and NLRP3-inflammasome activation which modulates inflammatory cytokine secretion from macrophages.

Background: A recombinant fusion protein combining the adjuvant and TLR5-ligand flagellin with the major birch pollen allergen Bet v 1 (rFlaA:Betv1) has been suggested to prevent the manifestation of birch allergy. Noteworthy, rFlaA:Betv1 induced both pro- and anti-inflammatory responses which were differentially regulated. However, the mechanism by which flagellin fusion proteins modulate allergen-specific immune responses, especially the mechanisms underlying IL-1β secretion and their contribution to the overall immune responses remains elusive.

Peach extract induces systemic and local immune responses in an experimental food allergy model.

Peach allergy is among the most frequent food allergies in the Mediterranean area, often eliciting severe anaphylactic reactions in patients. Due to the risk of severe symptoms, studies in humans are limited, leading to a lack of therapeutic options. This study aimed to develop a peach allergy mouse model as a tool to better understand the pathomechanism and to allow preclinical investigations on the development of optimized strategies for immunotherapy.

Role of Glycolysis and Fatty Acid Synthesis in the Activation and T Cell-Modulating Potential of Dendritic Cells Stimulated with a TLR5-Ligand Allergen Fusion Protein.

Trained immune responses, based on metabolic and epigenetic changes in innate immune cells, are de facto innate immune memory and, therefore, are of great interest in vaccine development. In previous studies, the recombinant fusion protein rFlaA:Betv1, combining the adjuvant and toll-like receptor (TLR)5-ligand flagellin (FlaA) and the major birch pollen allergen Bet v 1 into a single molecule, significantly suppressed allergic sensitization in vivo while also changing the metabolism of myeloid dendritic cells (mDCs). Within this study, the immune-metabolic effects of rFlaA:Betv1 during mDC activation were elucidated.

Stimulation of naïve B cells with a fusion protein consisting of FlaA and Bet v 1 induces regulatory B cells ex vivo.

Background: The experimental fusion protein rFlaA:Betv1 was shown to efficiently suppress allergen-specific sensitization in mice. However, the detailed mechanism of rFlaA:Betv1-mediated immune modulation is not fully understood. In this study, we investigated the effect of rFlaA:Betv1 on naïve murine B cells.

Modulation of dendritic cell metabolism by an MPLA-adjuvanted allergen product for specific immunotherapy.

Background: Recently, bacterial components were shown to enhance immune responses by shifting immune cell metabolism towards glycolysis and lactic acid production, also known as the Warburg Effect. Currently, the effect of allergen products for immunotherapy (AIT) and commercial vaccines on immune cell metabolism is mostly unknown.

Objective: To investigate the effect of AIT products (adjuvanted with either MPLA or Alum) on myeloid dendritic cell (mDC) metabolism and activation.

Allergenic Properties and Molecular Characteristics of PR-1 Proteins.

Only a small fraction of proteins in plants and animals are classified as allergens. The allergenic properties are frequently attributed to certain functional characteristics of the proteins, such as a role in the plant defense against biotic and abiotic stress, to achieve the systematic acquired resistance. In line with this, eight members out of 17 functional pathogenesis-related (PR) protein families have been characterized as allergens.

Does the Food Ingredient Pectin Provide a Risk for Patients Allergic to Non-Specific Lipid-Transfer Proteins?

Pectin, a dietary fiber, is a polysaccharide that is widely used in food industry as a gelling agent. In addition, prebiotic and beneficial immunomodulatory effects of pectin have been demonstrated, leading to increased importance as food supplement. However, as cases of anaphylactic reactions after consumption of pectin-supplemented foods have been reported, the present study aims to evaluate the allergy risk of pectin.

The Fusion Protein rFlaA:Betv1 Modulates DC Responses by a p38-MAPK and COX2-Dependent Secretion of PGE from Epithelial Cells.

Developing new adjuvants/vaccines and better understanding their mode-of-action is an important task. To specifically improve birch pollen allergy treatment, we designed a fusion protein consisting of major birch pollen allergen Betv1 conjugated to the TLR5-ligand flagellin (rFlaA:Betv1). This study investigates the immune-modulatory effects of rFlaA:Betv1 on airway epithelial cells.

The Flagellin:Allergen Fusion Protein rFlaA:Betv1 Induces a MyD88- and MAPK-Dependent Activation of Glucose Metabolism in Macrophages.

TLR5 ligand flagellin-containing fusion proteins are potential vaccine candidates for many diseases. A recombinant fusion protein of flagellin A and the major birch pollen allergen Bet v 1 (rFlaA:Betv1) modulates immune responses in vitro and in vivo. We studied the effects of rFlaA:Betv1 on bone marrow-derived macrophages (BMDMs).

The Dietary Fiber Pectin: Health Benefits and Potential for the Treatment of Allergies by Modulation of Gut Microbiota.

Purpose Of Review: The incidence of allergies is increasing and has been associated with several environmental factors including westernized diets. Changes in environment and nutrition can result in dysbiosis of the skin, gut, and lung microbiota altering the production of microbial metabolites, which may in turn generate epigenetic modifications. The present review addresses studies on pectin-mediated effects on allergies, including the immune modulating mechanisms by bacterial metabolites.

β-(1→4)-Mannobiose Acts as an Immunostimulatory Molecule in Murine Dendritic Cells by Binding the TLR4/MD-2 Complex.

Some β-mannans, including those in coffee bean and soy, contain a mannose backbone with β-(1→4) bonds. Such mannooligosaccharides could have immunological functions involving direct interaction with immune cells, in addition to acting as prebiotics. This study aimed at assessing the immunological function of mannooligosaccharides with β-(1→4) bond, and elucidating their mechanism of action using bone marrow-derived murine dendritic cells (BMDCs).

Human monocyte-derived type 1 and 2 macrophages recognize Ara h 1, a major peanut allergen, by different mechanisms.

Evidence has suggested that major peanut allergen Ara h 1 activates dendritic cells (DCs) via interaction with DC-SIGN (dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin), a C-type lectin receptor, and contributes to development of peanut allergy. Since macrophages, as well as DCs, play a crucial role in innate immunity, we investigated whether natural Ara h 1 (nAra h 1) activates two different subsets of macrophages, human monocyte derived macrophage type 1 (hMDM1: pro-inflammatory model) and type 2 (hMDM2: anti-inflammatory model). hMDM1 and hMDM2 predominantly produced pro-inflammatory cytokines (IL-6 and TNF-α) and an anti-inflammatory cytokine (IL-10) in response to nAra h 1, respectively.

Allergenicity assessment of the edible cricket Acheta domesticus in terms of thermal and gastrointestinal processing and IgE cross-reactivity with shrimp.

The allergenic potency of the cricket Acheta domesticus, a promising edible insect, has never been assessed. This work aims to study the immunoreactivity of Acheta domesticus, and its cross-reactivity with the shrimp Litopenaeus vannamei, assessing the effect of cooking and gastrointestinal digestion on their allergenic properties. Different cricket proteins were detected by immunoblotting with shrimp-allergic patients' sera.

The key to the allergenicity of lipid transfer protein (LTP) ligands: A structural characterization.

Plant lipid transfer proteins are a large family that can be found in all land plants. They have a hydrophobic cavity that allows them to harbor lipids and facilitates their traffic between membranes. However, in humans, this plant protein family is responsible for the main food allergies in the Mediterranean area.