2S albumins are relevant and often major allergens from several tree nuts and seeds, affecting mainly children and young people. The present study aims to assess how the structural features of 2S albumins could affect their immunogenic capacity, which is essential to comprehend the role of these proteins in food allergy. For this purpose, twelve 2S albumins were isolated from their respective extracts by chromatographic methods and identified by MALDI-TOF mass-spectrometry. Their molecular and structural characterization was conducted by electrophoretic, spectroscopic and in silico methods, showing that these are small proteins that comprise a wide range of isoelectric points, displaying a general high structure stability to thermal treatment. Despite low amino acid sequence identity, these proteins share structural features, pointing conformational epitopes to explain cross-reactivity between them. Immunoblotting with allergic patients’ sera revealed those possible correlations between evolutionarily distant 2S albumins from different sources. The availability of a well-characterized panel of 2S albumins from plant-derived sources allowed establishing correlations between their structural features and their allergenic potential, including their role in cross-reactivity processes.

This study reports on the interactions of egg proteins, which represent a major health concern in food allergy, with polyphenols obtained from orange and lemon peels. The antioxidant properties of such citrus peel extracts prior to protein binding were evaluated. The resulting edible, and therefore inherently safe, matrices exhibit reduced IgE binding compared to pure proteins in indirect immunological assays (ELISA) using individual sera from patients allergic to ovalbumin and lysozyme. The reduced allergenicity could arise from the interactions with polyphenols, which alter the structure and functionality of the native proteins. It is hypothesized that the anti-inflammatory and antioxidant properties of the polyphenols, described as inhibitors of the allergic response, could add immunomodulatory features to the hypoallergenic complexes. A docking analysis using lysozyme was conducted to scrutinize the nature of the protein–polyphenol interactions. An in silico study unravelled the complexity of binding modes depending on the isoforms considered. Altogether, the presented results validate the antioxidant properties and reduced allergenicity of polyphenol-fortified proteins. Lastly, this study highlights the upgrading of vegetable wastes as a source of natural antioxidants, thus showing the benefits of a circular economy in agri-food science.

The consumption of macadamia nuts has increased due to their cardioprotective and antioxidant properties. However, this rise is consistent with an increase in the cases of macadamia nut allergy, leading to severe reactions. Although two Macadamia integrifolia allergens (Mac i 1 and Mac i 2) have been identified in Australian and Japanese patients, the allergenic sensitization patterns in Western European populations, particularly in Spain, remain unclear. For this purpose, seven patients with macadamia nut allergy were recruited in Spain. Macadamia nut protein extracts were prepared and, together with hazelnut and walnut extracts, were used in Western blot and inhibition assays. IgE-reactive proteins were identified using MALDI-TOF/TOF mass spectrometry (MS). Immunoblotting assays revealed various IgE-binding proteins in macadamia nut extracts. Mass spectrometry identified three new allergens: an oleosin, a pectin acetylesterase, and an aspartyl protease. Cross-reactivity studies showed that hazelnut extract but not walnut extract inhibited macadamia nut oleosin-specific IgE binding. This suggests that oleosin could be used as marker for macadamia–hazelnut cross-reactivity. The results show an allergenic profile in the Spanish cohort different from that previously detected in Australian and Japanese populations. The distinct sensitization profiles observed highlight the potential influence of dietary habits and environmental factors exposure on allergenicity.

Cross-allergies affect a significant proportion of the population, and contribute to detrimental health and socioeconomic impacts, yet allergen immunotherapies often target a single allergen source disregarding cross-reactive allergens from other sources. Here we introduce an immunization approach developed for improved desensitization in cross-allergic patients using a consensus allergen (cnsLTP1), which contains orthologous non-specific lipid transfer proteins (nsLTP) derived from relevant fruit and pollen allergens. In BALB/c mice, vaccination via either mRNA-lipid nanoparticle (LNP) vehicle or traditional protein formulation induces cnsLTP1-specific IgGs capable of recognizing and binding to multiple nsLTPs. These IgGs block allergen binding by patient serum IgEs and prevent humanized rat basophil degranulation in vitro. Meanwhile, in an allergic mouse model, the mRNA-LNP formulation is tolerated and induces allergen-specific IgG responses but does not ameliorate subsequent allergen challenge responses. Regardless, this cross-allergen mRNA-LNP-based immunotherapy may have translation value once route of administration, formulation and/or dosing are optimized.

The growing production of plastics has led to widespread environmental contamination by micro- and nanoplastics (MNPLs), raising increasing concern about their potential impact on human respiratory health. Among them, nanoplastics (NPs) can penetrate deeply into the lungs. However, their impact on human bronchial epithelial cells remains poorly characterized. Here, we assessed the effects of 40 nm polystyrene (PS)-NPs on human bronchial Calu-3 cells cultured at the air-liquid interface (ALI) during early epithelial establishment, a three-dimensional model representing a functionally immature or compromised airway epithelial barrier. Chronic exposure (120 h) to PS-NPs (12 and 120 µg/cm²) interfered with barrier establishment in a concentration- and time-dependent manner, as demonstrated by reduced transepithelial electrical resistance (TEER) and decreased expression of the junctional proteins E-cadherin and Zonula Occludens-1 (ZO-1). PS-NPs also promoted the release of multiple inflammatory mediators, with osteopontin (OPN), a recognized biomarker of air pollution exposure, together with IL-2 and IL-10, showing the most consistent increases across both epithelial compartments. Other cytokines displayed concentration- and compartment-dependent secretion patterns. This polarized secretion pattern suggests selective activation of epithelial signaling pathways and paracrine communication toward the submucosal milieu. Furthermore, PS-NPs were internalized by Calu-3 cells and packaged into extracellular vesicles (EVs), a process that may limit acute cellular damage while potentially enabling propagation of NP-induced signals. Overall, these findings indicate that PS-NP exposure perturbs epithelial barrier function and polarized intercellular communication under conditions mimicking a compromised airway epithelium, suggesting a mechanistic role for NPs as aggravating factors of pre-existing epithelial dysfunction.

Pollen-food allergy syndrome (PFAS) affects a significant proportion of the global population with a major health and socioeconomic impact. Patients are generally treated against the major sensitized allergen which does not warrant protection against cross-reactive allergens, leading to long and ineffective treatment regimens. For food allergies, patient guidelines rely on source avoidance, leading to dietary restrictions and reduced quality of life - in particular for those suffering from PFAS. To overcome these limitations, we introduce a novel allergy immunotherapy (AIT) approach utilizing consensus allergens and mRNA technology to achieve broader, safer, and faster desensitization in PFAS patients. We first designed a consensus allergen of orthologs of non-specific Lipid Transfer Proteins (cnsLTP-1) representing a broad spectrum of nsLTP allergens prevalent in food and pollen sources. CnsLTP-1 was delivered to naïve BALB/c mice using mRNA-lipid nanoparticles (mRNA-LNP) as vehicle, or by a traditional protein formulation, to assess if it elicits broad protection against allergens from different sources. Immunization with both mRNA-LNP and protein formulations demonstrated that cnsLTP-1-specific IgGs could be induced, whilst the mRNA-LNP formulation notably avoided the induction of allergen-specific IgEs. The induced antibodies were capable of recognizing and binding to a variety of nsLTPs, and effectively blocked the binding of allergens by allergic patient serum IgEs. This study thus demonstrates that the presented AIT strategy, based on mRNA-LNP technology and consensus allergens, could find clinical utility by addressing the limitations of current AIT. Further development of this technology platform could pave the way for more effective and patient-friendly treatments for PFAS and other cross-reactive allergies.