O fruto proibido, um caso de alergia oral / The forbidden fruit, a case of oral allergy

Trinta a 60% das alergias alimentares em adolescentes e adultos são associadas à alergia ao pólen e estão incluídas na síndrome pólen-frutas (SPF). Esta síndrome é caracterizada por sintomas alérgicos provocados pela ingestão de frutas ou vegetais frescos em pacientes com rinite/rinoconjuntivite alérgica sazonal. Os autores apresentam o caso clínico de um adolescente que após sensibilização primária através de pólens de gramíneas e oliveira manifestou posteriormente, por reatividade cruzada, sintomas de alergia oral com a ingestão de frutas frescas. Após recurso ao método de diagnóstico Immuno-Solid-Phase Allergen Chip (ISAC) verificou-se que as profilinas foram as proteínas responsáveis pela reatividade cruzada.

In adolescents and adults, 30% to 60% of food allergies are associated with pollen allergy and are included in the pollen-food syndrome (PFS). This syndrome is characterized by allergic symptoms elicited by the ingestion of fresh fruits or vegetables in patients with seasonal allergic rhinitis/rhinoconjunctivitis. The authors present the clinical case of an adolescent who, after primary sensitization to grass and olive tree pollens, subsequently manifested by cross-reactivity symptoms of oral allergy with the ingestion of fresh fruit. After diagnostic workup with the Immuno- Solid-phase Allergen Chip (ISAC) assay, profilins were identified as the proteins responsible for the cross-reactivity.

[Oral allergy syndrome (OAS)]. / Síndrome polen-alimento (síndrome de alergia por vía oral).

The pollen-food allergy syndrome, also known as oral allergy syndrome, is characterized by local reactions in the mouth and throat after consuming certain raw plant foods in individuals sensitized to pollen from grass, weeds, and trees. Birch-apple is the prototype of this syndrome, with apple, pear, and plum being the most commonly associated foods. Symptoms are usually limited to the oral cavity but can include systemic reactions, including anaphylaxis. Sensitization to pollen allergens, such as lipid transfer proteins, profilin, and PR-10 proteins, triggers this syndrome. Its prevalence varies by geographic region and the predominant pollen type, affecting between 30% and 60% of food allergies. Diagnosis involves a clinical history, skin tests, and, in ambiguous cases, double-blind, placebo-controlled oral food challenges. Treatment primarily involves avoiding trigger foods.

El síndrome de alergia a alimentos y pólenes, también conocido como síndrome polen-alimento o síndrome de alergia oral, se caracteriza por una reacción local en la boca y faringe después de ingerir ciertos alimentos vegetales crudos, en individuos sensibilizados al polen de hierbas, malezas y árboles. El abedul-manzana es el prototipo de este síndrome, siendo la manzana, pera y ciruela los alimentos más comúnmente asociados. Los síntomas suelen limitarse a la cavidad oral, pero pueden incluir reacciones sistémicas, incluida la anafilaxia. La sensibilización a alérgenos de polen, como las proteínas de transferencia de lípidos, profilina y proteínas PR-10, desencadena este síndrome. Su prevalencia varía según la región geográfica y el tipo de polen predominante, afectando entre el 30% y el 60% de las alergias alimentarias. El diagnóstico implica historia clínica, pruebas cutáneas y, en casos ambiguos, pruebas de provocación alimentaria oral. El tratamiento consiste principalmente en evitar los alimentos desencadenantes.

Identification and characterization of profilin gene family in rice

BACKGROUND Profilin proteins (PRFs) are small (12­15 kD) actin-binding protein, which play a significant role in cytoskeleton dynamics and plant development via regulating actin polymerization. Profilins have been well documented in Arabidopsis, Zea mays L. as well as Phaseolus vulgaris, however no such fully characterization of rice (Oryza sativa L.) profilin gene family has been reported thus far. RESULTS In the present study, a comprehensive genome-wide analysis of rice PRF genes was completed and three members were identified. OsPRF1 and OsPRF2 shared 98.5% similarity (6 nucleotide divergence), but the deduced amino acid sequences of OsPRF1 and OsPRF2 are fully identical. In contrast, the OsPRF3 presents relatively lower similarity with OsPRF1 and OsPRF2. Phylogenetic analysis also support that OsPRF1 has a closer relationship with OsPRF2. Expression pattern analysis revealed the differential expression of OsPRFs in tissues of mature plant, which suggested the potential spatial functional specificity for rice profilin genes. Subcellular localization analysis revealed the OsPRFs were localized in cytoplasm and nucleus and all of them could bind actin monomers. Furthermore, abiotic stresses and hormones treatments assay indicated that the three OsPRF genes could be differentially regulated, suggesting that OsPRF genes might participate in different stress processes in rice. CONCLUSIONS Taken together, our study provides a comprehensive analysis of the OsPRF gene family and will provide a basis for further studies on their roles in rice development and in response to abiotic stresses

Synergistic effect of GRA7 and profilin proteins in vaccination against chronic Toxoplasma gondii infection.

Toxoplasmosis is a zoonotic disease with worldwide prevalence in humans and warm-blooded animal populations. In livestock Toxoplasma gondii is the causal agent of significant economic losses since it can cause abortions in goats and sheep. It is estimated that one third of the world population is infected. Although there are effective therapies for acute infection, these are sometimes poorly tolerated, teratogenic, and have a long administration time. Considering the deficiencies that exist related to the prevention and treatment of toxoplasmosis, the development of a safe and effective vaccine would be extremely valuable in fighting against this infection. In the present work, we characterize for the first time the adjuvant and immunogenic potential of a recombinant profilin protein (rTgPF), in a vaccine formulation alone or in combination with the well-known GRA7 antigen candidate in a murine toxoplasmosis model. Since TgPF acts as a ligand for TLR11 and 12 inducing innate immune responses that promote type 1 adaptive responses, we first study the capacity of the mix rGRA7 + rTgPF to initiate an immune response by evaluating dendritic cell activation. Both rTgPF and rGRA7 induces activation of mouse BMDCs more efficiently than the single proteins, evidenced by increased expression of CD80 and CD86 co-stimulatory proteins and secretion of IL-6, IL-10 and IL-12 cytokines after in vitro stimulation. The sum of the effects of rGRA7 and rTgPF on BMDCs maturation led us to assay them in a vaccination protocol. BALB/c mice vaccinated with this mix elicited a Th1-biased immunity via the induction of lymphocyte proliferation, activation of CD4+T cells and increased IFN-γ production that resulted in enhanced protection against chronic Toxoplama gondii infection. Profilin per se induce only cellular immunity but augments the effect of rGRA7 immune responses when used together, thus allowing us to postulate rTgPF as a potential adjuvant in a protein vaccine.

Novel murine mAbs define specific and cross-reactive epitopes on the latex profilin panallergen Hev b 8.

The production of specific antibodies able to recognize allergens from different sources or block interactions between allergens and antibodies mediating allergic reactions is crucial for developing successful tools for diagnostics and therapeutics. Panallergens are highly conserved proteins present in widely different species, implicated in relevant cross-reactions. The panallergen latex profilin (Hev b 8) has been associated with the latex-food-pollen syndrome. We generated five monoclonal IgGs and one IgE from murine hybridomas against recombinant Hev b 8 and evaluated their interaction with this allergen using ELISA and biolayer interferometry (BLI). Affinity purified mAbs exhibited high binding affinities towards rHev b 8, with KD1 values ranging from 10-10 M to 10-11 M. Some of these antibodies also recognized the recombinant profilins from maize and tomato (Zea m 12 and Sola l 1), and the ash tree pollen (Fra e 2). Competition ELISA demonstrated that some mAb pairs could bind simultaneously to rHev b 8. Using BLI, we detected competitive, non-competitive, and partial-competition interactions between pairs of mAbs with rHev b 8, suggesting the existence of at least two non-overlapping epitopes on the surface of this allergen. Three-dimensional models of the Fv of 1B4 and 2D10 IgGs and docking simulations of these Fvs with rHev b 8 revealed these epitopes. Furthermore, these two mAbs inhibited the interaction of polyclonal IgE and IgG4 antibodies from profilin-allergic patients with rHev b 8, indicating that the mAbs and the antibodies present in sera from allergic patients bind to overlapping epitopes on the allergen. These mAbs can be useful tools for immune-localization studies, immunoassay development, or standardization of allergenic products.

Heat-Stable Hazelnut Profilin: Molecular Dynamics Simulations and Immunoinformatics Analysis.

Heat treatment can modify the allergenic potential, reducing allergenicity in specific proteins. Profilins are one of the important hazelnut allergens; these proteins are considered panallergens due to their high capacity for cross-reactivity with other allergens. In the present work, we evaluated the thermostability of hazelnut profilin, combining molecular dynamics simulation and immunoinformatic techniques. This approach helped us to have reliable results in immunogenicity studies. We modeled Cor a 2 profilin and applied annealing simulation, equilibrium, and production simulation at constant temperatures ranging from 300 to 500 K using Gromacs software. Despite the hazelnut profilins being able to withstand temperatures of up to 400 K, this does not seem to reduce its allergenicity. We have found that profilin subjected to temperatures of 450 and 500 K could generate cross-reactivity with other food allergens. In conclusion, we note a remarkable thermostability of Cor a 2 at 400 K which avoids its structural unfolding.

Expression of profilin in Trypanosoma cruzi and identification of some of its ligands.

The role and regulation of actin in Trypanosoma cruzi and other related parasites is largely unknown. Based on early genome analysis, it was proposed that there was a reduced dependency on the acto-myosin system in the trypanosomatid parasites. However, more recent studies have extended the set of potential actin regulatory proteins, particularly for T. cruzi. One of the identified actin-binding proteins in trypanosomatids is profilin. In other systems, it is capable of simultaneously binding both monomeric actin and several actin-regulatory factors. Hence, the study of profilin and its ligands may help to identify novel pathways in which actin is involved. In T. cruzi, profilin is encoded by a single copy gene. In this work, we demonstrated that this gene is constitutively expressed in both insect and mammalian stages of the parasite, and that the protein is diffusely distributed. Furthermore, we identified some of its potential ligands by LC-MS using GST-profilin pull-down assays of parasite's protein extracts. Many of them were trypanosomatid specific proteins with unknown functions, although proteins from the carbohydrate metabolism, and two metallopeptidases were also detected. As expected, known ligands of profilin in other organisms were identified, including actin, the microtubule components, and the elongation factor 1-alpha. Our work suggests that profilin and the actin system may be regulated by unknown factors and participate in novel biological processes.

Fusion of foreign T-cell epitopes and addition of TLR agonists enhance immunity against Neospora caninum profilin in cattle.

We demonstrated recently that immunization with recombinant Neospora caninum profilin (rNcPRO) induces limited protection and a regulatory T-cell response in mice. The aim of this study was to evaluate the immune response elicited by rNcPRO in cattle and assess a strategy to enhance its immunogenicity, combining the addition of T-cell epitopes and immune modulators. We developed a chimeric recombinant profilin fused to functional T-cell epitopes present in the N-terminal sequence of vesicular stomatitis virus (VSV) glycoprotein G (rNcPRO/G). Groups of three cattle were immunized with two doses (2 weeks apart) of rNcPRO or rNcPRO/G formulated with alum hydroxide or a nanoparticulated soya-based adjuvant enriched with Toll-like receptor (TLR) 2 and TLR9 agonists, aimed to tackle the MyD88 pathway (AVECplus). rNcPRO induced only a primary immune response (IgM mediated), while antibodies in rNcPRO/G-vaccinated animals switched to IgG1 after the booster. The vaccine formulated with rNcPRO/G and AVECplus improved the production of systemic IFN-γ and induced long-term recall B-cell responses. Overall, our study provides data supporting the use of T-cell epitopes from VSV glycoprotein G and TLR agonists to enhance and modulate immunity to peptide antigens in bovines, particularly when using small proteins from parasites for which immune responses are usually feeble.

Immunization with Neospora caninum profilin induces limited protection and a regulatory T-cell response in mice.

Profilins are actin-binding proteins that regulate the polymerization of actin filaments. In apicomplexan parasites, they are essential for invasion. Profilins also trigger the immune response of the host by activating TLRs on dendritic cells (DCs), inducing the production of pro-inflammatory cytokines. In this study we characterized for the first time the immune response and protection elicited by a vaccine based on Neospora caninum profilin in mice. Groups of eight BALB/c mice received either two doses of a recombinant N. caninum profilin expressed in Escherichia coli. (rNcPRO) or PBS, both formulated with an aqueous soy-based adjuvant enriched in TLR-agonists. Specific anti-profilin antibodies were detected in rNcPRO-vaccinated animals, mainly IgM and IgG3, which were consumed after infection. Splenocytes from rNcPRO-immunized animals proliferated after an in vitro stimulation with rNcPRO before and after challenge. An impairment of the cellular response was observed in NcPRO vaccinated and infected mice following an in vitro stimulation with native antigens of N. caninum, related to an increase in the percentage of CD4+CD25+FoxP3+. Two out of five rNcPRO-vaccinated challenged mice were protected; they were negative for parasite DNA in the brain and showed no histopathological lesions, which were found in all PBS-vaccinated animals. As a whole, our results provide evidence of a regulatory response elicited by immunization with rNcPRO, and suggest a role of profilin in the modulation and/or evasion of immune responses against N. caninum.