NLRP3 priming due to skin damage precedes LTP allergic sensitization in a mouse model.

Allergic sensitization is initiated by protein and epithelia interaction, although the molecular mechanisms leading this encounter toward an allergic phenotype remain unknown. Here, we apply the two-hit hypothesis of inflammatory diseases to the study of food allergy sensitization. First, we studied the effects of long-term depilation in mice by analyzing samples at different time points. Several weeks of depilation were needed until clear immunological changes were evidenced, starting with upregulation of NLRP3 protein levels, which was followed by overexpression of Il1b and Il18 transcripts. Secondly, we assessed the effects of allergen addition (in this case, Pru p 3 in complex with its natural lipid ligand) over depilated skin. Systemic sensitization was evaluated by intraperitoneal provocation with Pru p 3 and measure of body temperature. Anaphylaxis was achieved, but only in mice sensitized with Prup3_complex and not treated with the NLRP3 inhibitor MCC950, thus demonstrating the importance of both hits (depilation + allergen addition) in the consecution of the allergic phenotype. In addition, allergen encounter (but not depilation) promoted skin remodeling, as well as CD45+ infiltration not only in the sensitized area (the skin), but across several mucosal tissues (skin, lungs, and gut), furtherly validating the systemization of the response. Finally, a low-scale study with human ILC2s is reported, where we demonstrate that Prup3_complex can induce their phenotype switch (↑CD86, ↑S1P1) when cultured in vitro, although more data is needed to understand the implications of these changes in food allergy development.

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 CxxxCx(10-14)CxxxC 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. The structures of one peanut (AH1.1) and 3 walnut (JR2.1, JR2.2, JR2.3) VBPs were solved using solution NMR, revealing similar α-hairpin structures stabilized by disulfide bonds with high levels of surface similarity. Peptide microarrays identified several peptide sequences primarily on AH1.1 and JR2.1, which were recognized by peanut-, walnut-, and dual-allergic patient IgE, establishing these peanut and walnut VBPs as potential mediators of allergenicity and cross-reactivity. JR2.2 and JR2.3 displayed extreme resilience against endosomal digestion, potentially hindering epitope generation and likely contributing to their reduced allergic potential.

HLA alleles and sustained peanut consumption promote IgG4 responses in subjects protected from peanut allergy.

We investigated the interplay between genetics and oral peanut protein exposure in the determination of the immunological response to peanut using the targeted intervention in the LEAP clinical trial. We identified an association between peanut-specific IgG4 and HLA-DQA1*01:02 that was only observed in the presence of sustained oral peanut protein exposure. The association between IgG4 and HLA-DQA1*01:02 was driven by IgG4 specific for the Ara h 2 component. Once peanut consumption ceased, the association between IgG4-specific Ara h 2 and HLA-DQA1*01:02 was attenuated. The association was validated by observing expanded IgG4-specific epitopes in people who carried HLA-DQA1*01:02. Notably, we confirmed the previously reported associations with HLA-DQA1*01:02 and peanut allergy risk in the absence of oral peanut protein exposure. Interaction between HLA and presence or absence of exposure to peanut in an allergen- and epitope-specific manner implicates a mechanism of antigen recognition that is fundamental to driving immune responses related to allergy risk or protection.

Aptamer based point of care diagnostic for the detection of food allergens.

Aptamers, due to their small size, strong target affinity, and ease of chemical modification, are ideally suited for molecular detection technologies. Here, we describe successful use of aptamer technology in a consumer device for the detection of peanut antigen in food. The novel aptamer-based protein detection method is robust across a wide variety of food matrices and sensitive to peanut protein at concentrations as low as 12.5 ppm (37.5 µg peanut protein in the sample). Integration of the assay into a sensitive, stable, and consumer friendly portable device will empower users to easily and quickly assess the presence of peanut allergens in foods before eating. With many food reactions occurring outside the home, the type of technology described here has significant potential to improve lives for children and families.

Pattern of sensitization to Juniperus oxycedrus 4EF-hand polcalcin, Jun o 4, compared with the 2EF-hand grass homolog Phl p 7 in a general Italian population of subjects suffering from pollinosis.

Cupressaceae pollen causes allergic reactions worldwide with long-lasting symptomatic periods. Currently, no cypress polcalcin is available for diagnostic purposes. With the aim to investigate the pattern of sensitization to a cypress polcalcin, a synthetic gene of Jun o 4, the Juniperus oxycedrus 4EF-hand polcalcin, was cloned and expressed in Escherichia coli. Its features were investigated in comparison with the grass 2EF-hand Phl p 7. Rhinitis was the symptom most frequently reported in a cohort of Italian patients sensitized to rJun o 4 and/or rPhl p 7. The detection of many pollen allergic patients sensitized to the cypress polcalcin, but negative to Phl p 7, indicates that Phl p 7 cannot be further considered a marker of sensitization towards all the polcalcins. A 4EF-hand cypress polcalcin claims the inclusion in allergy diagnostic tests. In addition, the sensitivity of polcalcins to gastrointestinal digestion is reported and discussed for the first time.

Detection of Wheat Lipid Transfer Protein (Tri a 14) Sensitization: Comparison between Currently Available Diagnostic Tools.

BACKGROUND: Wheat lipid transfer protein (LTP; Tri a 14) and ω5-gliadin have been described as major allergens in wheat allergy (WA) and relevant in wheat-induced anaphylaxis, frequently associated with cofactors. OBJECTIVE: The objective of this study was to compare tools currently available in routine diagnosis to detect Tri a 14 sensitization, its clinical relevance, and cosensitization to ω5-gliadin and other LTPs. METHODS: One hundred eighteen adults sensitized to rTri a 14 by ImmunoCAP® (cutoff ≥0.1 kUA/L) identified among 210 LTP allergic patients were included. We evaluated (1) wheat skin prick test (SPT), (2) specific IgE (sIgE) to wheat, rTri a 14, rTri a 19, peach, apple, walnut, hazelnut, and peanut LTPs using ImmunoCAP® and microarray ImmunoCAP®ISAC (cutoff ≥0.3I SU), and (3) wheat-related symptoms. RESULTS: Wheat SPT and sIgE were positive in 31% and 85% of subjects, respectively. rTri a 14 by microarray was detected in 25%. Eight percent showed cosensitization to ω5-gliadin. Thirty percent referred symptoms (gastrointestinal [13%], urticaria [11%], and anaphylaxis [8%]). Cofactors (45%) were significantly associated with systemic reactions. CONCLUSION: WA due to Tri a 14 is frequently related with systemic reactions and because are frequently related to cofactors, the culprit may not be suspected. Together with the poor performance to identify Tri a 14 sensitization of the current routine diagnostic tools based on the analysis of whole wheat extract, such as wheat SPT or sIgE, there is a high risk that WA may be overlooked. Thus, when WA is suspected, sIgE Tri a 14 assessment is recommended, together with wheat and ω5-gliadin, preferably in the singleplex format, and carefully evaluated considering ≥0.1 kUA/L as a cutoff.

Targeting immunodominant Bet v 1 epitopes with monoclonal antibodies prevents the birch allergic response.

BACKGROUND: Blocking the major cat allergen, Fel d 1, with mAbs was effective in preventing an acute cat allergic response. OBJECTIVES: This study sought to extend the allergen-specific antibody approach and demonstrate that a combination of mAbs targeting Bet v 1, the immunodominant and most abundant allergenic protein in birch pollen, can prevent the birch allergic response. METHODS: Bet v 1-specific mAbs, REGN5713, REGN5714, and REGN5715, were isolated using the VelocImmune platform. Surface plasmon resonance, x-ray crystallography, and cryo-electron microscopy determined binding kinetics and structural data. Inhibition of IgE-binding, basophil activation, and mast cell degranulation were assessed via blocking ELISA, flow cytometry, and the passive cutaneous anaphylaxis mouse model. RESULTS: REGN5713, REGN5714, and REGN5715 bind with high affinity and noncompetitively to Bet v 1. A cocktail of all 3 antibodies, REGN5713/14/15, blocks IgE binding to Bet v 1 and inhibits Bet v 1- and birch pollen extract-induced basophil activation ex vivo and mast cell degranulation in vivo. Crystal structures of the complex of Bet v 1 with immunoglobulin antigen-binding fragments of REGN5713 or REGN5715 show distinct interaction sites on Bet v 1. Cryo-electron microscopy reveals a planar and roughly symmetrical complex formed by REGN5713/14/15 bound to Bet v 1. CONCLUSIONS: These data confirm the immunodominance of Bet v 1 in birch allergy and demonstrate blockade of the birch allergic response with REGN5713/14/15. Structural analyses show simultaneous binding of REGN5713, REGN5714, and REGN5715 with substantial areas of Bet v 1 exposed, suggesting that targeting specific epitopes is sufficient to block the allergic response.

Novel antibody cocktail targeting Bet v 1 rapidly and sustainably treats birch allergy symptoms in a phase 1 study.

BACKGROUND: The efficacy of an allergen-specific IgG cocktail to treat cat allergy suggests that allergen-specific IgG may be a major protective mechanism elicited by allergen immunotherapy. OBJECTIVES: Extending these findings, we tested a Bet v 1-specific antibody cocktail in birch-allergic subjects. METHODS: This was a phase 1, randomized, double-blind, study with 2 parts. Part A administered ascending doses of the Bet v 1-specific antibody cocktail REGN5713/14/15 (150-900 mg) in 32 healthy adults. Part B administered a single subcutaneous 900-mg dose or placebo in 64 birch-allergic subjects. Total nasal symptom score response to titrated birch extract nasal allergen challenge and skin prick test (SPT) with birch and alder allergen were assessed at screening and days 8, 29, 57, and 113 (SPT only); basophil activation tests (n = 26) were conducted. RESULTS: Single-dose REGN5713/14/15 significantly reduced total nasal symptom score following birch nasal allergen challenge relative to baseline. Differences in total nasal symptom score areas under the curve (0-1 hour) for subjects treated with REGN5713/14/15 versus those given placebo (day 8: -1.17, P = .001; day 29: -1.18, P = .001; day 57: -0.85, P = .024) and titration SPT with birch difference in area under the curve of mean wheal diameters for subjects treated with REGN5713/14/15 versus placebo (all P < .001) were sustained for ≥2 months; similar results were observed with alder SPT. REGN5713/14/15 was well tolerated. Basophil responsiveness to birch-related allergens was significantly decreased in subjects treated with REGN5713/14/15 versus those given placebo on days 8, 57, and 113 (all P < .01). CONCLUSIONS: Single-dose REGN5713/14/15 was well tolerated and provided a rapid (1 week) and durable (2 months) reduction in allergic symptoms after birch allergen nasal allergen challenge, potentially offering a new paradigm for the treatment of birch allergy symptoms.

Association Between the Seed Storage Proteins 2S Albumin and 11S Globulin and Severe Allergic Reaction After Flaxseed Intake

Background: Given the increased popularity of flaxseed in meals, several cases of allergy to these seeds have been reported. Little is known about the allergens implicated in hypersensitivity reactions to flaxseed. The present study aimed to identify the allergens involved in IgE-mediated reactions in 5 patients with a clinical history of severe systemic symptoms after flaxseed consumption. Methods: Proteins that were potential allergens with IgE-binding capacity were purified from flaxseed extract using chromatography and identified via MALDI-TOF mass spectrometry. Immunoassays were performed using the 5 allergic patients’ sera tested individually and as a pool. Results: Immunoblotting of the flaxseed extract revealed a low-molecular-mass protein (around 13 kDa) in 4 of the 5 patients, while a protein of approximately 55 kDa was detected in 2 patients. The proteins were identified by mass spectrometry as flaxseed 2S albumin, which is included in the WHO/IUIS allergen nomenclature as Lin u 1, and 11S globulin. Inhibition assays revealed in vitro IgE-mediated cross-reactivity between Lin u 1 and peanut and cashew nut proteins, while IgE-mediated recognition of 11S globulin by patients’ sera was partially inhibited by several plant-derived sources. Conclusions: Seed storage proteins from flaxseed were involved in the development of severe symptoms in the 5 patients studied and exhibited cross-reactivity with other allergenic sources. Besides the severity of flaxseed allergy in patients sensitized to 2S albumin, this is the first time that 11S globulin has been identified as a potential allergen. Taking these data into account should ensure a more accurate diagnosis. (AU)

Antecedentes: Dada la creciente popularidad de la linaza en las comidas, se han notificado varios casos de alergia a estas semillas. La información acerca de los alérgenos implicados en las reacciones de hipersensibilidad a estas semillas es escasa. El presente trabajo pretende identificar los alérgenos implicados en las reacciones mediadas por IgE en cinco pacientes con una historia clínica de síntomas sistémicos graves tras el consumo de linaza. Métodos: Las proteínas susceptibles de ser alérgenos con capacidad de unir IgE se purificaron a partir del extracto de linaza mediante técnicas cromatográficas. Su identificación se realizó mediante espectrometría de masas MALDI-TOF. Se realizaron inmunoensayos con los sueros de los cinco pacientes alérgicos, utilizados de forma individual o como mezclas. Resultados: Cuatro de los cinco pacientes reconocieron una proteína de baja masa molecular (alrededor de 13 kDa) en inmunoensayos con extracto de linaza, mientras que dos pacientes reconocieron una proteína de aproximadamente 55 kDa. Se identificaron por espectrometría de masas como albúmina 2S de linaza, incluida en la nomenclatura de alérgenos de la OMS/IUIS como Lin u 1, y globulina 11S, respectivamente. Los ensayos de inhibición in vitro revelaron la existencia de reactividad cruzada de la Lin u 1 con las proteínas del cacahuete y del anacardo, mientras que el reconocimiento por parte de la IgE de la globulina 11S por parte de los sueros de los pacientes fue parcialmente inhibido por varias fuentes vegetales. Conclusiones: Las proteínas de almacenamiento de las semillas de lino estaban implicadas en el desarrollo de síntomas graves en cinco individuos y mostraron una reactividad cruzada con otras fuentes alergénicas. Además de la gravedad de la alergia a la linaza en los pacientes sensibilizados a la albúmina 2S, es la primera vez que se identifica la globulina 11S como un alérgeno potencial.

Risk Factors in Severe Anaphylaxis: Which Matters the Most, Food or Cofactors?

Background: The prevalence of anaphylactic shock, the most severe manifestation of anaphylaxis, remains unknown. Risk factors and biomarkers have not been fully identified. Objective: To identify risk factors in patients who experience anaphylactic shock. Methods: Using lipid transfer protein (LTP) allergy as a model, we compared the characteristics of patients who developed anaphylaxis and anaphylactic shock. We recorded demographics, pollen sensitization, foods ingested up to 2 hours before onset of the reaction, and the presence of cofactors. Culprit foods were identified through a compatible clinical history and positive allergology work-up (skin prick test and/or sIgE). Results: We evaluated 150 reactions in 55 patients with anaphylaxis (134 reactions) and 12 with anaphylactic shock (16 reactions). Patients in the anaphylaxis group experienced twice as many reactions (mean [SD], 2.4 [2.5] for anaphylaxis vs 1.3 [1.5] for anaphylactic shock; P<.02). No relationship was found between any food group and severity of the reaction. The most frequent food involved in both groups of patients was the combination of several plant-derived foods (plant food mix), followed by peach and nuts. Indeed, in the reactions caused by plant food mix, the presence of a cofactor was observed more often than in other food groups. On the other hand, cofactors were not present in peach- and nut-related reactions. Exercise was the most frequent cofactor in all groups. Conclusion: In our series, the severity of the reactions was not determined by the kind of food or presence of a cofactor. Anaphylactic shock seems to be an infrequent presentation that may be associated with other individual-related factors requiring further evaluation (AU)

Antecedentes: La prevalencia del shock anafiláctico sigue siendo desconocida. Aún no se han identificado completamente factores de riesgo ni biomarcadores. Objetivo: Identificar factores de riesgo de shock anafiláctico. Método: Utilizando la alergia a proteína de transferencia de lípidos (LTP) como modelo, se han comparado características de pacientes que han presentado una anafilaxia (An) y pacientes que han desarrollado un shock anafiláctico (SAn). Se recopilaron datos demográficos, sensibilización a pólenes, alimentos ingeridos hasta 2 horas antes del inicio de la reacción y la presencia o no de cofactores. El alimento implicado se identificó mediante historia clínica compatible y estudio alergológico positivo (prick test y/o IgE). Resultados: Se evaluaron un total de 150 reacciones; 55 pacientes del grupo An sufrieron 134 reacciones, y 12 pacientes del grupo SAn sufrieron 16 reacciones. El grupo An experimentó el doble de reacciones por paciente (media [DS] 2,4 [2,5] en An vs 1,3 [1,5] en SAn, p<0,02). No se observó relación entre el tipo de alimento y la gravedad de la reacción. El alimento implicado con más frecuencia en ambos grupos fue la combinación de varios vegetales (“mix de vegetales”), seguido por el melocotón y frutos secos. No hubo cofactores implicados en las reacciones con melocotón ni con frutos secos. En ambos grupos el eje rcicio fue el cofactor involucrado con más frecuencia.Conclusión: En nuestra serie, el alimento y la presencia de cofactor no determinan la gravedad de una reacción. Los shocks anafilácticos parecen ser una presentación infrecuente y podrían estar relacionados con factores individuales que precisarán una evaluación más extensa (AU)

Preventive Administration of Non-Allergenic Bet v 1 Peptides Reduces Allergic Sensitization to Major Birch Pollen Allergen, Bet v 1.

IgE-mediated allergy to birch pollen affects more than 100 million patients world-wide. Bet v 1, a 17 kDa protein is the major allergen in birch pollen responsible for allergic rhinoconjunctivitis and asthma in birch pollen allergic patients. Allergen-specific immunotherapy (AIT) based on therapeutic administration of Bet v 1-containing vaccines is an effective treatment for birch pollen allergy but no allergen-specific forms of prevention are available. We developed a mouse model for IgE sensitization to Bet v 1 based on subcutaneous injection of aluminum-hydroxide adsorbed recombinant Bet v 1 and performed a detailed characterization of the specificities of the IgE, IgG and CD4+ T cell responses in sensitized mice using seven synthetic peptides of 31-42 amino acids length which comprised the Bet v 1 sequence and the epitopes recognized by human CD4+ T cells. We then demonstrate that preventive systemic administration of a mix of synthetic non-allergenic Bet v 1 peptides to 3-4 week old mice significantly reduced allergic immune responses, including IgE, IgG, IgE-mediated basophil activation, CD4+ T cell and IL-4 responses to the complete Bet v 1 allergen but not to the unrelated major grass pollen allergen Phl p 5, without inducing Bet v 1-specific allergic sensitization or adaptive immunity. Our results thus demonstrate that early preventive administration of non-allergenic synthetic T cell epitope-containing allergen peptides could be a safe strategy for the prevention of allergen-specific IgE sensitization.

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). BMDMs differentiated from BALB/c, C57BL/6, TLR5-/-, or MyD88-/- mice were pre-treated with inhibitors, stimulated with rFlaA:Betv1 or respective controls, and analyzed for activation, cytokine secretion, metabolic state, RNA transcriptome, and modulation of allergen-specific Th2 responses. Stimulation of BMDMs with rFlaA:Betv1 resulted in MyD88-dependent production of IL-1ß, IL-6, TNF-α, IL-10, CD69 upregulation, and a pronounced shift towards glycolysis paralleled by activation of MAPK, NFκB, and mTOR signaling. Inhibition of either mTOR (rapamycin) or SAP/JNK-MAPK signaling (SP600125) resulted in dose-dependent metabolic suppression. In BMDM and T cell co-cultures, rFlaA:Betv1 stimulation suppressed rBet v 1-induced IL-5 and IL-13 secretion while inducing IFN-γ production. mRNA-Seq analyses showed HIF-1a, JAK, STAT, phagosome, NLR, NFκB, TNF, TLR, and chemokine signaling to participate in the interplay of cell activation, glycolysis, and immune response. rFlaA:Betv1 strongly activated BMDMs, resulting in MyD88-, MAPK-, and mTOR-dependent enhancement of glucose metabolism. Our results suggest macrophages are important target cells to consider during restauration of allergen tolerance during AIT.

Structural Alterations of Antigens at the Material Interface: An Early Decision Toolbox Facilitating Safe-by-Design Nanovaccine Development.

Nanomaterials have found extensive interest in the development of novel vaccines, as adjuvants and/or carriers in vaccination platforms. Conjugation of protein antigens at the particle surface by non-covalent adsorption is the most widely used approach in licensed particulate vaccines. Hence, it is essential to understand proteins' structural integrity at the material interface in order to develop safe-by-design nanovaccines. In this study, we utilized two model proteins, the wild-type allergen Bet v 1 and its hypoallergenic fold variant (BM4), to compare SiO2 nanoparticles with Alhydrogel® as particulate systems. A set of biophysical and functional assays including circular dichroism spectroscopy and proteolytic degradation was used to examine the antigens' structural integrity at the material interface. Conjugation of both biomolecules to the particulate systems decreased their proteolytic stability. However, we observed qualitative and quantitative differences in antigen processing concomitant with differences in their fold stability. These changes further led to an alteration in IgE epitope recognition. Here, we propose a toolbox of biophysical and functional in vitro assays for the suitability assessment of nanomaterials in the early stages of vaccine development. These tools will aid in safe-by-design innovations and allow fine-tuning the properties of nanoparticle candidates to shape a specific immune response.

An Updated Overview of Almond Allergens.

Tree nuts are considered an important food in healthy diets. However, for part of the world's population, they are one of the most common sources of food allergens causing acute allergic reactions that can become life-threatening. They are part of the Big Eight food groups which are responsible for more than 90% of food allergy cases in the United States, and within this group, almond allergies are persistent and normally severe and life-threatening. Almond is generally consumed raw, toasted or as an integral part of other foods. Its dietary consumption is generally associated with a reduced risk of cardiovascular diseases. Several almond proteins have been recognized as allergens. Six of them, namely Pru du 3, Pru du 4, Pru du 5, Pru du 6, Pru du 8 and Pru du 10, have been included in the WHO-IUIS list of allergens. Nevertheless, further studies are needed in relation to the accurate characterization of the already known almond allergens or putative ones and in relation to the IgE-binding properties of these allergens to avoid misidentifications. In this context, this work aims to critically review the almond allergy problematic and, specifically, to perform an extensive overview regarding known and novel putative almond allergens.

Natural Course and Prognostic Factors of Immediate-Type Peanut Allergy in Children.

BACKGROUND: Predicting food allergy resolution is essential to minimize the number of restricted foods in children. However, there have been no studies on the natural history of peanut allergy (PA) in Korea. OBJECTIVE: This study aimed to evaluate the natural course and prognostic factors of immediate-type PA in children till the age of 10 years. METHODS: We retrospectively collected data of 122 children who developed PA before 60 months of age from 3 tertiary hospitals in Korea. Diagnosis and resolution of PA was defined as an oral food challenge test or a convincing history of symptoms within 2 h after peanut ingestion. The prognostic factors for resolution of PA were identified using the Cox proportional hazard model. RESULTS: The median (interquartile range) age at diagnosis was 2.0 (1.3-3.0) years. Among the 122 children, PA resolved in 18 (14.8%) children. The level of peanut-specific IgE (sIgE) at diagnosis in the persistence group was significantly higher than that in the resolution group (p = 0.026). The probabilities of resolution of PA were 10.3% and 32.8% at the ages of 6 and 10 years, respectively. A peanut-sIgE level ≥1 kU/L at diagnosis was significantly associated with persistent PA (hazard ratio, 5.99; 95% confidence interval, 1.89-18.87). CONCLUSIONS: Only 10.3% of our patients had a probability of developing spontaneous resolution of PA by 6 years of age. Peanut-sIgE levels ≥1 kU/L at diagnosis were associated with the persistence of PA.

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.

Recombinant Bet v 1-BanLec chimera modulates functional characteristics of peritoneal murine macrophages by promoting IL-10 secretion.

Allergen-specific immunotherapy (AIT) is a desensitizing treatment for allergic diseases that corrects the underlined pathological immune response to innocuous protein antigens, called allergens. Recombinant allergens employed in the AIT allowed the production of well-defined formulations that possessed consistent quality but were often less efficient than natural allergen extracts. Combining recombinant allergens with an adjuvant or immunomodulatory agent could improve AIT efficacy. This study aimed to perform structural and functional characterization of newly designed recombinant chimera composed of the Bet v 1, the major birch pollen allergen, and Banana Lectin (BanLec), TLR2, and CD14 binding protein, for the application in AIT. rBet v 1-BanLec chimera was designed in silico and expressed as a soluble fraction in Escherichia coli. Purified rBet v 1-BanLec (33.4 kDa) retained BanLec-associated biological activity of carbohydrate-binding and preserved IgE reactive epitopes of Bet v 1. The chimera revealed secondary structures with predominant ß sheets. The immunomodulatory capacity of rBet v 1-BanLec tested on macrophages showed changes in myeloperoxidase activity, reduced NO production, and significant alterations in the production of cytokines when compared to both rBanLec and rBet v 1. Comparing to rBet v 1, rBet v 1-BanLec was demonstrated to be more efficient promoter of IL-10 production as well as weaker inducer of NO production and secretion of pro-inflammatory cytokines TNFα, and IL-6. The ability of rBet v 1-BanLec to promote IL-10 in together with the preserved 3D structure of Bet v 1 part implies that the construct might exert a beneficial effect in the allergen-specific immunotherapy.

Design of peptides with high affinity binding to a monoclonal antibody as a basis for immunotherapy.

About half of the US population is sensitized to one or more allergens, as found by a National Health and Nutrition Examination Survey (NHANES). The most common treatment for seasonal allergic responses is the daily use of oral antihistamines, which can control some of the symptoms, but are not effective for nasal congestion, and can be debilitating in many patients. Peptide immunotherapy is a promising new approach to treat allergic airway diseases. The small size of the immunogens cannot lead to an unwanted allergic reaction in sensitized patients, and the production of peptides with sufficient amounts for immunotherapy is time- and cost-effective. However, it is not known what peptides are the most effective for an immunotherapy of allergens. We previously produced a unique monoclonal antibody (mAb) E58, which can inhibit the binding of multiple groups of mAbs and human IgEs from patients affected by the major group 1 allergens of ragweed (Amb a 1) and conifer pollens (Jun a 1, Cup s 1, and Cry j 1). Here, we demonstrated that a combined approach, starting from two linear E58 epitopes of the tree pollen allergen Jun a 1 and the ragweed pollen allergen Amb a 1, and residue modifications suggested by molecular docking calculations and peptide design could identify a large number of high affinity binding peptides. We propose that this combined experimental and computational approach by structural analysis of linear IgE epitopes and peptide design, can lead to potential new candidates for peptide immunotherapy.