IgE and IgG4 epitopes of the peanut allergens shift following oral immunotherapy.

Background: Oral immunotherapy (OIT) with peanut () allergen powder-dnfp (PTAH; Aimmune Therapeutics) is an FDA-approved treatment to desensitize peanut allergic participants.

Objective: Here we assessed shifts in IgE and IgG4 binding to peanut allergens and their epitopes recognized by United States (US) peanut allergic participants ( = 20) enrolled in phase 3 PTAH OIT clinical trials.

Methods: Pre- and post- trial participant sera were collected approximately 12 months apart and tested for IgE binding to intact peanut proteins via ImmunoCAP ISAC immunoassays.

Structure and IgE Cross-Reactivity among Cashew, Pistachio, Walnut, and Peanut Vicilin-Buried Peptides.

Peanut and tree-nut allergies are frequently comorbid for reasons not completely understood. Vicilin-buried peptides (VBPs) are an emerging family of food allergens whose conserved structural fold could mediate peanut/tree-nut co-allergy. Peptide microarrays were used to identify immunoglobulin E (IgE) epitopes from the N-terminus of the vicilin allergens Ara h 1, Ana o 1, Jug r 2, and Pis v 3 using serum from three patient diagnosis groups: monoallergic to either peanuts or cashew/pistachio, or dual allergic.

IgE epitopes of Ara h 9, Jug r 3, and Pru p 3 in peanut-allergic individuals from Spain and the US.

Non-specific lipid transfer proteins (LTPs) are well studied allergens that can lead to severe reactions, but often cause oral allergy syndrome in the Mediterranean area and other European countries. However, studies focused on LTP reactivity in allergic individuals from the United States are lacking because they are not considered major allergens. The goal of this study is to determine if differences in immunoglobulin (Ig) E binding patterns to the peanut allergen Ara h 9 and two homologous LTPs (walnut Jug r 3 and peach Pru p 3) between the US and Spain contribute to differences observed in allergic reactivity.

Structure, Immunogenicity, and IgE Cross-Reactivity among Walnut and Peanut Vicilin-Buried Peptides.

Vicilin-buried peptides (VBPs) from edible plants are derived from the N-terminal leader sequences (LSs) of seed storage proteins. VBPs are defined by a common α-hairpin fold mediated by conserved CxxxCxCxxxC motifs. Here, peanut and walnut VBPs were characterized as potential mediators of both peanut/walnut allergenicity and cross-reactivity despite their low (∼17%) sequence identity.

Epitopes with similar physicochemical properties contribute to cross reactivity between peanut and tree nuts.

Many individuals with peanut (PN) allergy have severe reactions to tree nuts (TN) such as walnuts or cashews. Although allergenic proteins in TN and PN have overall low identity, they share discrete sequences similar in physicochemical properties (PCP) to known IgE epitopes. Here, PCP-consensus peptides (cp, 13 aa and 31 aa) were identified from an alignment of epitope rich regions of walnut vicilin, Jug r 2, leader sequence (J2LS) and cross-reactive epitopes in the 2S albumins of peanut and synthesized.

Contribution of Chemical Modifications and Conformational Epitopes to IgE Binding by Ara h 3.

Roasting is known to change the allergenic properties of peanuts. To study these observations at a molecular level, the relationship of IgE binding to the structure of Ara h 3 from raw and roasted peanuts was assessed. Ara h 3 (A3) was purified from raw (R), light roast (LR) and dark roast (DR) peanuts, the purity was assessed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the secondary structures were compared with circular dichroism (CD) spectroscopy.

Purification of Recombinant Peanut Allergen Ara h 1 and Comparison of IgE Binding to the Natural Protein.

Allergic reactions to food are on the rise worldwide and there is a corresponding increase in interest to understand the molecular mechanisms responsible. Peanut allergies are the most problematic because the reaction often persists into adulthood and can be as severe as anaphylaxis and death The purpose of the work presented here was to develop a reproducible method to produce large quantities of pure recombinant Ara h 1(rAra h 1) that will enable standardization of immunological tests for patients and allow structural and immunological studies on the wild type and mutagenized forms of the protein. Ara h 1 is initially a pre-pro-protein which, following two endoproteolytic cleavages, becomes the mature form found in peanut.

Importance of a specific amino acid pairing for murine MLL leukemias driven by MLLT1/3 or AFF1/4.

Acute leukemias caused by translocations of the MLL gene at chromosome 11 band q23 (11q23) are characterized by a unique gene expression profile. More recently, data from several laboratories indicate that the most commonly encountered MLL fusion proteins, MLLT1, MLLT3, and AFF1 are found within a molecular complex that facilitates the elongation phase of mRNA transcription. Mutational analyses suggest that interaction between the MLLT1/3 proteins and AFF family proteins are required for experimental transformation of hematopoietic progenitor cells (HPCs).

Ara h 1 structure is retained after roasting and is important for enhanced binding to IgE.

Scope: Ara h 1 from roasted peanut binds higher levels of serum immunoglobulin E than raw peanuts and this is likely due to the Maillard reaction. While Ara h 1 linear IgE epitopes have been mapped, the presence and importance of structural epitopes is not clear.

Methods And Results: Mass spectrometry, immunoblot, ELISA, circular dichroism (CD), and structural analysis were used to compare structural and subsequent IgE-binding differences in Ara h 1 purified from raw (N) and roasted peanuts (R) and denatured Ara h 1 (D).

Differences among heat-treated, raw, and commercial peanut extracts by skin testing and immunoblotting.

Background: Peanut allergenicity has been reported to be influenced by heat treatment, yet the commonly available extracts for skin prick testing (SPT) are derived from raw extracts.

Objective: To assess the effect of heat treatment on the SPT reactivity and specific IgE binding to peanut.

Methods: Three commercial extracts and 3 laboratory-prepared extracts, including raw, roasted, and boiled, were used for SPT in 19 patients with suspected peanut allergy and in 4 individuals who eat peanut without any symptoms.

Effects of boiling on the IgE-binding properties of tropomyosin of shrimp (Litopenaeus vannamei).

The thermal stability and IgE binding of raw and boiled shrimp extracts and the tropomyosins (TM) have not been reported. In this study, we compare the stability of raw and boiled shrimp TM of Litopenaeus vannamei and evaluate how boiling may alter the allergenicity of L. vannamei.

Processing can alter the properties of peanut extract preparations.

As peanut allergy is an increasing public health risk, affecting over 1% of the United States and United Kingdom school children, it is important that methods and reagents for accurate diagnosis of food allergy and detection of allergenic foods are reliable and consistent. Given that most current experimental, diagnostic, and detection tests rely on the presence of soluble allergens in food extracts, we investigated the effects of thermal processing on the solubility and IgE binding of the major peanut allergens, Ara h 1 and Ara h 2. The soluble and insoluble fractions of peanuts that were boiled, fried, and roasted were subjected to electrophoresis and Western blot analysis using anti-Ara h 1 and anti-Ara h 2 antibodies and serum IgE from peanut allergic individuals.

Identification of a novel mitogen-activated protein kinase in Toxoplasma gondii.

Toxoplasma gondii is an Apicomplexan parasite causing significant morbidity and mortality in immunocompromised hosts. Mitogen activated protein kinases regulate diverse biologic processes including proliferation, differentiation, survival and stress responses. We searched a new T.