Unraveling the Diagnosis of Kiwifruit Allergy: Usefulness of Current Diagnostic Tests.

OBJECTIVES: To determine the usefulness of the in vitro and in vivo methods used in the diagnosis of kiwifruit allergy and to specifically assess the impact of seed proteins on sensitivity. METHODS: We performed skin prick tests (SPTs) using various commercial extracts, homemade pulp, and seed extracts and prick-prick tests with kiwifruit on 36 allergic patients. The presence of specific IgE (sIgE) was assessed using the ImmunoCAP (kiwifruit extract), ELISA (Act d 1, Act d 2), ISAC, and FABER assays. Immunoblotting of seed extract was carried out, and a single-blind oral food challenge was performed with whole seeds in seed-sensitized individuals. RESULTS: The prick prick test with kiwifruit demonstrated the highest diagnostic capacity (81.8% sensitivity and 94.1% specificity) among the in vivo tests. The sIgE levels measured using ImmunoCAP (kiwifruit extract) showed a similar sensitivity to that of global ISAC and FABER (63.9%, 59.5%, and 58.3%, respectively). Act d 1 was the major allergen. Sensitization to Act d 1 was associated with positive sIgE results to whole kiwifruit extract detected by ImmunoCAP (P<.000). A positive SPT result to kiwifruit seeds was associated with severe symptoms induced by kiwifruit (P=.019) as a marker of advanced disease, but not with clinically relevant sensitization. Challenge testing with kiwifruit seeds performed on 8 seed-sensitized patients yielded negative results. CONCLUSION: Sensitization to Act d 1 is associated with a positive result in conventional diagnostic techniques, whereas kiwifruit seed sensitization does not increase the sensitivity of the diagnostic techniques evaluated.

Allergen Profile of London Plane Tree Pollen: Clinical and Molecular Pattern in Central Spain.

BACKGROUND AND OBJECTIVES: Platanus acerifolia (London plane tree) is a deciduous tree of the Platanaceae family. Sensitization to this plant varies with geography. Madrid, located in central Spain, has one of the highest London plane tree pollen concentration levels on the Iberian Peninsula. We evaluated both the clinical characteristics and the molecular sensitization pattern of patients with allergy to London plane tree pollen in the region of Madrid. METHODS: Thirty-eight patients allergic to London plane tree pollen were selected according to their clinical symptoms and positive results in skin prick testing and/or specific IgE determination. Serum was collected, and allergen components were evaluated using immunodetection techniques as well as ImmunoCAP. The IgE-binding proteins detected were identified and characterized using mass spectrometry. RESULTS: Analysis of serum samples from allergic patients revealed 9 IgE-binding bands in London plane tree pollen extract. Among these, the 45-kDa protein, which corresponded to Pla a 2, was detected in 76.3% of patients. However, the 18-kDa (Pla a 1) and 9-kDa (Pla a 3) bands were detected in 44.7% and 23.7% of sera, respectively. These results were confirmed using purified proteins. Characterization of the allergen revealed the 27-kDa protein to be glutathione-S-transferase. CONCLUSIONS: The molecular profile of patients sensitized to London plane tree pollen differs from that reported in studies from other locations. In the population we studied, the prevalence of Pla a 2 was higher than that of Pla a 1 and Pla a 3. In addition, the minor allergen previously referred to as Pla a 4 was characterized as glutathione-S-transferase.

Allergen Profile of London Plane Tree Pollen: Clinical and Molecular Pattern in Central Spain

Background: Platanus acerifolia (London plane tree) is a deciduous tree of the Platanaceae family. Sensitization to this plant varies withgeography. Madrid, located in central Spain, has one of the highest London plane tree pollen concentration levels on the Iberian Peninsula.Objectives: We evaluated both the clinical characteristics and the molecular sensitization pattern of patients with allergy to London planetree pollen in the region of Madrid.Patients and Methods: Thirty-eight patients allergic to London plane tree pollen were selected according to their clinical symptoms andpositive results in skin prick testing and/or specific IgE determination. Serum was collected, and allergen components were evaluatedusing immunodetection techniques as well as ImmunoCAP. The IgE-binding proteins detected were identified and characterized usingmass spectrometry.Results: Analysis of serum samples from allergic patients revealed 9 IgE-binding bands in London plane tree pollen extract. Among these,the 45-kDa protein, which corresponded to Pla a 2, was detected in 76.3% of patients. However, the 18-kDa (Pla a 1) and 9-kDa (Pla a 3)bands were detected in 44.7% and 23.7% of sera, respectively. These results were confirmed using purified proteins. Characterization ofthe allergen revealed the 27-kDa protein to be glutathione-S-transferase.Conclusions: The molecular profile of patients sensitized to London plane tree pollen differs from that reported in studies from otherlocations. In the population we studied, the prevalence of Pla a 2 was higher than that of Pla a 1 and Pla a 3. In addition, the minorallergen previously referred to as Pla a 4 was characterized as glutathione-S-transferase. (AU)

Antecedentes: Platanus acerifolia es un árbol de hoja caduca de la familia Platanaceae. La sensibilización frente a esta planta varía enfunción de la zona geográfica. Madrid, ubicada en el centro de España, tiene uno de los mayores niveles de concentración de polen deeste árbol en la Península Ibérica.Objetivo: Evaluar las características clínicas y los patrones moleculares de sensibilización en pacientes con alergia al plátano de sombraen la región de Madrid.Pacientes y Métodos: Treinta y ocho pacientes alérgicos al polen del plátano de sombra fueron seleccionados de acuerdo con los síntomasclínicos, pruebas cutáneas positivas y/o IgE específica. El suero se recogió y se evaluaron los componentes alérgicos mediante técnicas deinmunodetección, así como ImmunoCAP. Las proteínas que unían IgE fueron identificadas y caracterizadas por espectrometría de masas.Resultados: El análisis de los sueros de los pacientes alérgicos reveló 9 bandas que captaban IgE en los extractos de polen de plátano desombra. Entre estas, la proteína de 45 kDa, correspondiente a Pla a 2, se detectó en el 76,3% de los pacientes. Sin embargo, las bandasde 18 kDa (Pla a 1) y 9 kDa (Pla a 3) fueron reconocidas en el 44,7% y 27,3%, respectivamente. Estos resultados se confirmaron usandoproteínas purificadas. La caracterización de los alérgenos identificó la proteína de 27 kDa como una glutatión S-transferasa.Conclusiones: El perfil molecular de los pacientes sensibilizados al polen del plátano de sombra varía respecto al descrito en estudios deotras localizaciones. Nuestra población muestra una mayor prevalencia de Pla a 2 comparado con Pla a 1 y Pla a 3. Además, el alérgenominoritario previamente denominado Pla a 4 fue caracterizado como una glutatión-S-transferasa. (AU)

Unraveling the Diagnosis of Kiwifruit Allergy: Usefulness of Current Diagnostic Tests

Objectives: To determine the usefulness of the in vitro and in vivo methods used in the diagnosis of kiwifruit allergy and to specificallyassess the impact of seed proteins on sensitivity.Methods: We performed skin prick tests (SPTs) using various commercial extracts, homemade pulp, and seed extracts and prick-prick testswith kiwifruit on 36 allergic patients. The presence of specific IgE (sIgE) was assessed using the ImmunoCAP (kiwifruit extract), ELISA(Act d 1, Act d 2), ISAC, and FABER assays. Immunoblotting of seed extract was carried out, and a single-blind oral food challenge wasperformed with whole seeds in seed-sensitized individuals.Results: The prick prick test with kiwifruit demonstrated the highest diagnostic capacity (81.8% sensitivity and 94.1% specificity) amongthe in vivo tests. The sIgE levels measured using ImmunoCAP (kiwifruit extract) showed a similar sensitivity to that of global ISAC andFABER (63.9%, 59.5%, and 58.3%, respectively). Act d 1 was the major allergen. Sensitization to Act d 1 was associated with positivesIgE results to whole kiwifruit extract detected by ImmunoCAP (P<.000). A positive SPT result to kiwifruit seeds was associated withsevere symptoms induced by kiwifruit (P=.019) as a marker of advanced disease, but not with clinically relevant sensitization. Challengetesting with kiwifruit seeds performed on 8 seed-sensitized patients yielded negative results.Conclusions: Sensitization to Act d 1 is associated with a positive result in conventional diagnostic techniques, whereas kiwifruit seedsensitization does not increase the sensitivity of the diagnostic techniques evaluated (AU)

Objetivos: Determinar la rentabilidad diagnóstica de las técnicas in vitro e in vivo utilizadas en el diagnóstico de alergia al kiwi y estudiarla influencia de las proteínas alergénicas de las semillas en su sensibilidad.Métodos: Se seleccionaron 36 pacientes alérgicos a kiwi. Se les realizó prick test con cuatro extractos comerciales diferentes y prick-prickcon kiwi. Se determinó IgE específica mediante ImmunoCAP (extracto de kiwi), ELISA (Act d 1, Act d 2), las micromatrices ISAC y FABER eImmunoblotting de extracto de semilla de kiwi. Se realizó exposición oral simple ciego frente a semilla de kiwi en pacientes sensibilizadosa la semilla.Resultados: El prick-prick de kiwi fue la prueba in vivo con mayor rendimiento (sensibilidad 81,8%, especificidad 94,1%). El ImmunoCAPde extracto de kiwi mostró una sensibilidad similar a la global del ISAC y del FABER (63,9%, 59,5% y 58,3%, respectivamente). Act d 1fue el alérgeno mayoritario. Se encontró asociación entre los niveles de IgE específica frente a Act d 1 (ISAC) y el extracto de kiwi medianteImmunoCAP (p <0,000). La prueba cutánea positiva con semilla se asoció con mayor gravedad de síntomas frente a kiwi (p = 0,019),como marcador de enfermedad avanzada, pero no como sensibilización clínicamente relevante. La prueba de provocación con semillasfue negativa en los ocho pacientes provocados.Conclusiones: La sensibilización a Act d 1 se asocia con resultados positivos con las técnicas diagnósticas convencionales. La sensibilizaciónfrente a semillas no mejora el rendimiento de las técnicas evaluadas (AU)

Developing an Optical Interferometric Detection Method based biosensor for detecting specific SARS-CoV-2 immunoglobulins in Serum and Saliva, and their corresponding ELISA correlation.

The standard rapid approach for the diagnosis of coronavirus disease 2019 (COVID-19) is the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA. The detection of specific anti-SARS-CoV-2 immunoglobulins is crucial for screening people who have been exposed to the virus, whether or not they presented symptoms. Recent publications report different methods for the detection of specific IgGs, IgMs, and IgAs against SARS-CoV-2; these methods mainly detect immunoglobulins in the serum using conventional techniques such as rapid lateral flow tests or enzyme-linked immunosorbent assay (ELISA). In this article, we report the production of recombinant SARS-CoV-2 spike protein and the development of a rapid, reliable, cost-effective test, capable of detecting immunoglobulins in serum and saliva samples. This method is based on interferometric optical detection. The results obtained using this method and those obtained using ELISA were compared. Owing to its low cost and simplicity, this test can be used periodically for the early detection, surveillance, detection of immunity, and control of the spread of COVID-19.

A new optical interferometric-based in vitro detection system for the specific IgE detection in serum of the main peach allergen.

Food allergens cause worldwide chronic diseases with a great impact on public health. Immunoglobulins E (IgEs) trigger allergic reactions by specifically binding the allergens to which the allergic patients are sensitized. In this scientific work we report for the first time a new optical interferometric in vitro system for the detection of specific IgEs (sIgEs) to the principal peach allergen (Pru p 3) in real serum samples. Interferometric Optical Detection Method (IODM) was employed for reading out the signal of Fabry-Perot based interferometers acting as biotransducers. Pru p 3 was immobilized as bioreceptor onto the sensing surface for detecting the target biomolecules, sIgEs to Pru p 3. Moreover, the demanding low concentration of IgE, compared to other analytes in real serum samples, made it necessary to use nanoparticles (NPs) for two reasons: to collect only the IgEs from the serum sample and to enhance the optical interferometric read-out signal. The methodology was validated in advance by scanning electron microscopy (SEM). Consequently, we report in this article a novel high-performance in vitro detection method to recognize sIgE to molecular allergens by means of silicon dioxide (SiO2) NPs. Finally, this scientific work provides the basis for the in vitro component resolved diagnosis (CRD) of sIgEs to molecular allergens.

Mechanisms underlying induction of allergic sensitization by Pru p 3.

BACKGROUND: Recently, the nature of the lipid-ligand of Pru p 3, one of the most common plant food allergens in southern Europe, has been identified as a derivative of the alkaloid camptothecin bound to phytosphingosine. However, the origin of its immunological activity is still unknown. OBJECTIVE: We sought to evaluate the role of the Pru p 3 lipid-ligand in the immunogenic activity of Pru p 3. METHODS: In vitro cultures of different cell types (monocyte-derived dendritic cells [moDCs], PBMCs [peripheral blood mononuclear cells] and epithelial and iNKT-hybridoma cell lines) have been used to determine the immunological capacity of the ligand, by measuring cell proliferation, maturation markers and cytokine production. To study the capacity of the lipid-ligand to promote sensitization to Pru p 3 in vivo, a mouse model of anaphylaxis to peach has been produced and changes in the humoral and basophil responses have been analysed. RESULTS: The lipid-ligand of Pru p 3 induced maturation of moDCsc and proliferation of PBMCs. Its immunological activity resided in the phytosphingosine tail of the ligand. The adjuvant activity of the ligand was also confirmed in vivo, where the complex of Pru p 3-ligand induced higher levels of IgE than Pru p 3 alone. The immunological capacity of the Pru p 3 ligand was mediated by CD1d, as maturation of moDCs was inhibited by anti-CD1d antibodies and Pru p 3-ligand co-localized with CD1d on epithelial cells. Finally, Pru p 3-ligand presented by CD1d was able to interact with iNKTs. CONCLUSIONS AND CLINICAL RELEVANCE: The Pru p 3 lipid-ligand could act as an adjuvant to promote sensitization to Pru p 3, through its recognition by CD1d receptors. This intrinsic adjuvant activity of the accompanying lipid cargo could be a general essential feature of the mechanism underlying the phenomenon of allergenicity.

Bronchial Challenge With Tri a 14 as an Alternative Diagnostic Test for Baker's Asthma.

BACKGROUND: Baker's asthma (BA) is the most prevalent occupational respiratory disease in developed countries. It is caused by inhalation of wheat dust in the working environment and affects 1%-10% of workers in the baking industry. Diagnosis of BA is based on bronchial challenge with wheat, a technique that carries a high risk for patients. The wheat lipid transfer protein Tri a 14 is a major allergen in BA. OBJECTIVE: The aim of our study was to characterize Tri a 14 as a marker of BA in order to prevent patients from having to undergo bronchial challenge with wheat. METHODS: The study population comprised 55 patients selected at the Rio Hortega Hospital, Valladolid, Spain. Patients with BA were diagnosed using a skin prick test (SPT) with wheat and Tri a 14 and bronchial challenge test (BCT) with wheat. Patients with food allergy had a clear clinical history of allergy to peach confirmed by positive SPT to peach extract and Pru p 3. RESULTS: All patients in the BA group had a positive SPT result with wheat (100%), and most had positive results with Tri a 14 (95%). A positive BCT result with Tri a 14 was also observed in 22 of 27 of the patients with BA (82%). The response to Tri a 14 was specifically associated with BA. CONCLUSION: Tri a 14 is a good marker of BA and can be used in SPT and BCT as an alternative diagnostic method, thus avoiding bronchial challenge with wheat and reducing the risk associated with this technique.

Bronchial challenge with Tri a 14 as an alternative diagnostic test for Baker’s asthma

Background: Baker's asthma (BA) is the most prevalent occupational respiratory disease in developed countries. It is caused by inhalation of wheat dust in the working environment and affects 1%-10% of workers in the baking industry. Diagnosis of BA is based on bronchial challenge with wheat, a technique that carries a high risk for patients. The wheat lipid transfer protein Tri a 14 is a major allergen in BA. Objective: The aim of our study was to characterize Tri a 14 as a marker of BA in order to prevent patients from having to undergo bronchial challenge with wheat. Methods: The study population comprised 55 patients selected at the Rio Hortega Hospital, Valladolid, Spain. Patients with BA were diagnosed using a skin prick test (SPT) with wheat and Tri a 14 and bronchial challenge test (BCT) with wheat. Patients with food allergy had a clear clinical history of allergy to peach confirmed by positive SPT to peach extract and Pru p 3. Results: All patients in the BA group had a positive SPT result with wheat (100%), and most had positive results with Tri a 14 (95%). A positive BCT result with Tri a 14 was also observed in 22 of 27 of the patients with BA (82%). The response to Tri a 14 was specifically associated with BA. Conclusion: Tri a 14 is a good marker of BA and can be used in SPT and BCT as an alternative diagnostic method, thus avoiding bronchial challenge with wheat and reducing the risk associated with this technique (AU)

Antecedentes: El asma del panadero (BA) es la enfermedad respiratoria ocupacional más frecuente en los países occidentales. Está causada por la inhalación diaria de harina de trigo en el entorno de trabajo, afectando entre 1-10% de los trabajadores de la industria panadera. El diagnóstico de BA se basa en la provocación bronquial con trigo, una técnica de alto riesgo para los pacientes. La proteína de transferencia de lípidos de trigo (LTP) Tri a 14 ha sido descrita como alérgeno principal en esta patología. Objetivo: El objetivo de nuestro estudio ha sido caracterizar Tri a 14 como marcador de BA, y así evitar la provocación bronquial con trigo en estos pacientes. Métodos: Para ello, se seleccionaron cincuenta y cinco pacientes en el Hospital Río Hortega de Valladolid, España. Resultados: Los pacientes diagnosticados con BA mostraron prueba cutánea (SPT) positiva a trigo (100%) y la mayoría también a Tri a 14 (95%). Todos ellos, fueron sometidos a provocación bronquial con Tri a 14, observándose un resultado positivo en 22/27 de los sujetos evaluados (82%). Conclusiones: En base a esto, se puede concluir que Tri a 14 es un buen marcador de BA, y podría ser utilizado en SPT y provocación bronquial como método diagnóstico, reduciendo el uso de la provocación bronquial con trigo y el riesgo asociado a esta técnica (AU)

Characterization of profilin and polcalcin panallergens from ash pollen.

BACKGROUND: Ash (Fraxinus excelsior) is an important source of allergenic pollen in temperate areas of Europe. Profilin and polcalcin are 2 important panallergens involved in cross-reactivity between different sources. OBJECTIVE: To clone and produce Fra e 2 (profilin) and Fra e 3 (polcalcin) as recombinant proteins and evaluate their immunological properties using the natural forms obtained from ash pollen. METHODS: Total RNA from ash pollen was used as a template to obtain the specific complementary DNA (cDNA) sequences of the 2 panallergens. The cDNA-encoding sequences were cloned into the pET11b expression vector and used to transform BL21 (DE3) Escherichia coli cells. Proteins were expressed, purified by chromatography, and characterized structurally by circular dichroism, mass spectrometry, and immunologically by western blot and ELISA using profilin and polcalcin polyclonal antibodies and human sera from ash pollen-sensitized patients. RESULTS: Profilin and polcalcin amino acid sequences from ash pollen showed a high degree of identity with homologous allergens from different sources. The cDNA-encoding allergen sequences were expressed as nonfusion recombinant proteins and purified to homogeneity. Secondary structure values were similar to those obtained from other members of these families. Allergenic properties of the recombinant allergens were observed to be equivalent to those of the natural counterparts of F excelsior pollen. CONCLUSIONS: Fra e 2 and Fra e 3 recombinant allergens might be used in clinical diagnosis to determine profilin- and polcalcin-specific IgE levels present in the sera of ash pollen-sensitized patients, thus facilitating the finding of the sensitizing source in areas with complex sensitization profiles.

Characterization of profilin and polcalcin panallergens from ash pollen

Background: Ash ( Fraxinus excelsior ) is an important source of allergenic pollen in temperate areas of Europe. Profilin and polcalcin are 2 important panallergens involved in cross-reactivity between different sources. Objective: To clone and produce Fra e 2 (profilin) and Fra e 3 (polcalcin) as recombinant proteins and evaluate their immunological properties using the natural forms obtained from ash pollen. Methods: Total RNA from ash pollen was used as a template to obtain the specific complementary DNA (cDNA) sequences of the 2 panallergens. The cDNA-encoding sequences were cloned into the pET11b expression vector and used to transform BL21 (DE3) Escherichia coli cells. Proteins were expressed, purified by chromatography, and characterized structurally by circular dichroism, mass spectrometry, and immunologically by western blot and ELISA using profilin and polcalcin polyclonal antibodies and human sera from ash pollen-sensitized patients. Results: Profilin and polcalcin amino acid sequences from ash pollen showed a high degree of identity with homologous allergens from different sources. The cDNA-encoding allergen sequences were expressed as nonfusion recombinant proteins and purified to homogeneity. Secondary structure values were similar to those obtained from other members of these families. Allergenic properties of the recombinant allergens were observed to be equivalent to those of the natural counterparts of F excelsior pollen. Conclusions: Fra e 2 and Fra e 3 recombinant allergens might be used in clinical diagnosis to determine profilin- and polcalcin-specific IgE levels present in the sera of ash pollen-sensitized patients, thus facilitating the finding of the sensitizing source in areas with complex sensitization profiles (AU)

Antecedentes: El polen de fresno (Fraxinus excelsior ) es una importante fuente alergénica en zonas cálidas de Europa. La profilina y polcalcina son 2 panalérgenos implicados en reactividad cruzada. Objetivos: Clonar y producir Fra e 2 (profilina) y Fra e 3 (polcalcina) como alérgenos recombinantes. Comparar sus propiedades inmunológicas con sus formas naturales del polen de fresno. Métodos: El RNA total de polen de fresno se utilizó como molde para obtener los cDNAs específicos de ambos panalérgenos. Dichos cDNAs se clonaron en el vector de expresión pET11b y se transformaron células de Escherichia coli BL21(DE3). Las proteínas se caracterizaron mediante dicroísmo circular, espectrometría de masas, inmunodetección en membrana y ELISA utilizando anticuerpos policlonales frente a profilina y polcalcina y sueros de pacientes alérgicos al polen de fresno. Resultados: Las secuencias de aminoácidos de la profilina y polcalcina de polen de fresno presentaban una identidad de secuencia elevada con alérgenos homólogos. Dichos alérgenos se expresaron como proteínas recombinantes independientes y se purificaron a homogeneidad. Los valores de estructura secundaria fueron similares a los de otros miembros de estas familias. Las propiedades alergénicas de los alérgenos recombinantes resultaron ser equivalentes a los de sus homólogos naturales del polen. Conclusiones: Los alérgenos recombinantes Fra e 2 y Fra e 3 podrían usarse en diagnóstico clínico para determinar los niveles de IgE específicos para profilina y polcalcina en los sueros de los pacientes sensibilizados al polen de fresno, facilitando así la identificación de la fuente sensibilizante en áreas donde los pacientes presentan perfiles alergénicos complejos (AU)

Allergenic characterization of new mutant forms of Pru p 3 as new immunotherapy vaccines.

Nowadays, treatment of food allergy only considered the avoidance of the specific food. However, the possibility of cross-reactivity makes this practice not very effective. Immunotherapy may exhibit as a good alternative to food allergy treatment. The use of hypoallergenic molecules with reduced IgE binding capacity but with ability to stimulate the immune system is a promising tool which could be developed for immunotherapy. In this study, three mutants of Pru p 3, the principal allergen of peach, were produced based on the described mimotope and T cell epitopes, by changing the specific residues to alanine, named as Pru p 3.01, Pru p 3.02, and Pru p 3.03. Pru p 3.01 showed very similar allergenic activity as the wild type by in vitro assays. However, Pru p 3.02 and Pru p 3.03 presented reduced IgE binding with respect to the native form, by in vitro, ex vivo, and in vivo assays. In addition, Pru p 3.03 had affected the IgG4 binding capacity and presented a random circular dichroism, which was reflected in the nonrecognition by specific antibodies anti-Pru p 3. Nevertheless, both Pru p 3.02 and Pru p 3.03 maintained the binding to IgG1 and their ability to activate T lymphocytes. Thus, Pru p 3.02 and Pru p 3.03 could be good candidates for potential immunotherapy in peach-allergic patients.

Transport of Pru p 3 across gastrointestinal epithelium - an essential step towards the induction of food allergy?

BACKGROUND: Since intestinal absorption of food protein can trigger an allergic reaction, the effect of plant food allergen on intestinal epithelial cell permeability and its ability to cross the epithelial monolayer was evaluated. OBJECTIVE: To study the interaction of Pru p 3 with intestinal epithelium, its natural entrance, analyzing transport kinetics and cellular responses that trigger. METHODS: This was achieved using Pru p 3, the peach LTP, as a model. Enterocytic monolayers were established by culturing Caco 2 cells, as a model of enterocytes, on permeable supports that separate the apical and basal compartments. Pru p 3 was added to the apical compartment, the transepithelial resistance (TEER) was measured, and the transport was quantified. RESULTS: The peach allergen that crossed the cell monolayer was detected in the cell fraction and in the basal medium by immunodetection with specific antibodies and the quantity was measured by ELISA assay. Pru p 3 was able to cross the monolayer without disturbing the integrity of the tight junctions. This transport was significantly higher than that of a non-allergenic peach LTP, LTP1, and occurred via lipid raft pathway. The incubation of Caco 2 cells with Pru p 3 and LTP1 produced the expression of epithelial-specific cytokines TSLP, IL33 and IL25. CONCLUSION: These results suggest that Pru p 3 was able to cross the cell monolayer by the transcellular route and then induce the production of Th2 cytokines. The results of the present study represent a step towards clarifying the importance of Pru p 3 as a sensitizer. CLINICAL RELEVANCE: The capacity of food allergens to cross the intestinal monolayer could explain their high allergenic capacity and its fast diffusion through the body associating to severe symptoms.