Parallel use of CID, HCD and ETD for characterization of proteic allergens found in pollensomes

Comunicaciones a congreso

Ole e 15 and its human counterpart -PPIA- chimeras reveal an heterogeneous IgE response in olive pollen allergic patients

Olive pollen is a major cause of immunoglobulin E (IgE)-mediated allergy in Mediterranean countries. It is expected to become a worldwide leading allergenic source because olive cultivation is increasing in many countries. Ole e 15 belongs to the cyclophilin pan-allergen family, which includes highly cross-reactive allergens from non-related plant, animal and mold species. Here, the amino acid differences between Ole e 15 and its weak cross-reactive human homolog PPIA were grafted onto Ole e 15 to assess the contribution of specific surface areas to the IgE-binding. Eight Ole e 15-PPIA chimeras were produced in E. coli, purified and tested with 20 sera from Ole e 15-sensitized patients with olive pollen allergy by ELISA experiments. The contribution of linear epitopes was analyzed using twelve overlapping peptides spanning the entire Ole e 15 sequence. All the patients displayed a diverse reduction of the IgE-reactivity to the chimeras, revealing a highly polyclonal and patient-specific response to Ole e 15. IgE-epitopes are distributed across the entire Ole e 15 surface. Two main surface areas containing relevant conformational epitopes have been characterized. This is the first study to identify important IgE-binding regions on the surface of an allergenic cyclophilin.We thank the excellent technical support of Sara Abián Saz. This work was supported by grants cofounded by Fondo Europeo de Desarrollo Regional (FEDER): SAF2014-53209-R to M.V. and R.B. and SAF2017-86483-R to M.V. from the Ministerio de Economía y Competitividad and by the Thematic Networks and Co-operative Research Centres: RIRAAF Network RD12/0013/0015; and ARADyAL (RD16/0006/0014) from the Instituto de Salud Carlos III (ISCIII). A.N. and A.J. acknowledge PI-01119-2016 from the Consejería de Salud (Junta de Andalucía) and the Alergosur Foundation. R.B. also acknowledges the financial support of the PI17CIII/00045 grant from the AES-ISCIII program. The FPU predoctoral contract to P.S.S.-A. is supported by the Spanish Ministerio de Educación, Cultura y Deporte. C.O.-S. was supported by a contract of the Programa Operativo de Empleo Juvenil y la Iniciativa de Empleo Juvenil (YEI) with the participation of the Consejería de Educación, Juventud y Deporte de la Comunidad de Madrid y del Fondo Social Europeo.S

Sal k 5, a member of the widespread Ole e 1-like protein family, is a new allergen of Russian thistle (Salsola kali) pollen.

Salsola kali is an Amaranthaceae weed with important repercussions for pollinosis in temperate areas. Ole e 1-like members are relevant allergens in pollen from different species. We aimed to characterize and produce as recombinant allergen S. kali Ole e 1-like protein. METHODS:The natural allergen was purified at homogeneity after three chromatographic steps. Specific cDNA was sequenced and expressed in Pichia pastoris yeast. Structural relationships of natural and recombinant forms were carried out by 2D electrophoresis and spectroscopic analyses. Its immunological relevance was analyzed by ELISA and immunoblotting using an IgG antiserum and monoclonal antibodies specific to Ole e 1, as well as sera from 57 allergic patients recruited from two Spanish regions where this pollinosis is frequent. RESULTS:The purified allergen, Sal k 5, is an acidic glycoprotein of 151 amino acid residues and 17,628 Da of molecular mass. Its amino acid sequence exhibits 68 and 32% identity with the allergens of Che a 1 and Ole e 1, respectively. The recombinant protein was correctly processed and its structural and immunologic equivalence to the natural form was proven. A sensitization frequency between 30 and 40% was observed in pollinic patients from the center and east coast of Spain. CONCLUSIONS:Sal k 5 is a member of the Ole e 1-like protein family which can be considered an important allergen from S. kali. Its inclusion in diagnosis protocols would allow the accurate defining of patients allergic to this pollen

The Allergenic Structure of the Thaumatinlike Protein Ole e 13 Is Degraded by Processing of Raw Olive Fruits

Background: The thaumatin-like protein (TLP) Ole e 13 in raw olive fruit is responsible for occupational allergy in olive oil mill workers. However,these workers do not experience allergic symptoms after ingestion of edible olive.Objectives: To analyze the presence of IgE-reactive TLP in raw and edible olive fruit and to assess the allergenic potency of both sources.Methods: The content of TLP in raw and edible olive fruit protein extracts was analyzed using immunoblotting with sera from allergic patients and with olive TLP–specific IgG. The structural and immunological stability of TLP were assayed using immunoblotting after treatment of both raw olive and purified TLP with 0.25 M NaOH solution for 24 hours. Olive pollen extract was investigated by immunoblotting for TLP content. Results: The TLP contained in raw olive fruit was not present in edible olives as a result of maceration before human consumption. No TLP was detected in olive pollen using specific IgG or sera from patients allergic to olive fruit. Sera from patients allergic to olive pollen did not react with purified TLP. Conclusions: IgE-reactive TLP is not present in edible olive, thus explaining the low number of patients allergic to this highly consumed fruit. Patients allergic to olive pollen are not sensitized to TLP and, therefore, not expected to be at risk of food allergy to olive fruit or TLP plant source

An Enzymatically Active β-1,3-Glucanase from Ash Pollen with Allergenic Properties: A Particular Member in the Oleaceae Family

Endo-β-1,3-glucanases are widespread enzymes with glycosyl hydrolitic activity involved in carbohydrate remodelling during the germination and pollen tube growth. Although members of this protein family with allergenic activity have been reported, their effective contribution to allergy is little known. In this work, we identified Fra e 9 as a novel allergenic β-1,3-glucanase from ash pollen. We produced the catalytic and carbohydrate-binding domains as two independent recombinant proteins and characterized them from structural, biochemical and immunological point of view in comparison to their counterparts from olive pollen. We showed that despite having significant differences in biochemical activity Fra e 9 and Ole e 9 display similar IgE-binding capacity, suggesting that β-1,3-glucanases represent an heterogeneous family that could display intrinsic allergenic capacity. Specific cDNA encoding Fra e 9 was cloned and sequenced. The full-length cDNA encoded a polypeptide chain of 461 amino acids containing a signal peptide of 29 residues, leading to a mature protein of 47760.2 Da and a pI of 8.66. An N-terminal catalytic domain and a C-terminal carbohydrate-binding module are the components of this enzyme. Despite the phylogenetic proximity to the olive pollen β-1,3-glucanase, Ole e 9, there is only a 39% identity between both sequences. The N- and C-terminal domains have been produced as independent recombinant proteins in Escherichia coli and Pichia pastoris, respectively. Although a low or null enzymatic activity has been associated to long β-1,3-glucanases, the recombinant N-terminal domain has 200-fold higher hydrolytic activity on laminarin than reported for Ole e 9. The C-terminal domain of Fra e 9, a cysteine-rich compact structure, is able to bind laminarin. Both molecules retain comparable IgE-binding capacity when assayed with allergic sera. In summary, the structural and functional comparison between these two closely phylogenetic related enzymes provides novel insights into the complexity of β-1,3-glucanases, representing a heterogeneous protein family with intrinsic allergenic capacity

Der p 1 based immunotoxin as potential tool for the treatment of dust mite respiratory allergy

Immunotoxins appear as promising therapeutic molecules, alternative to allergen-specifcimmunotherapy. In this work, we achieved the development of a protein chimera able to promote specifc cell death on efector cells involved in the allergic reaction. Der p 1 allergen was chosen as cell-targeting domain and the powerful ribotoxin α-sarcin as the toxic moiety. The resultant construction, named proDerp1αS, was produced and purifed from the yeast Pichia pastoris. Der p 1-protease activity and α-sarcin ribonucleolytic action were efectively conserved in proDerp1αS. Immunotoxin impact was assayed by using efector cells sensitized with house dust mite-allergic sera. Cell degranulation and death, triggered by proDerp1αS, was exclusively observed on Der p 1 sera sensitized-humRBL-2H3 cells, but not when treated with non-allergic sera. Most notably, equivalent IgE-binding and degranulation were observed with both proDerp1αS construct and native Der p 1 when using purifed basophils from sensitized patients. However, proDerp1αS did not cause any cytotoxic efect on these cells, apparently due to its lack of internalization after their surface IgEbinding, showing the complex in vivo panorama governing allergic reactions. In conclusion, herein we present proDerp1αS as a proof of concept for a potential and alternative new designs of therapeutic tools for allergies. Development of new, and more specifc, second-generation of immunotoxins following proDerp1αS, is further discussed

Direct PCR-free electrochemical biosensing of plant-food derived nucleic acids in genomic DNA extracts. Application to the determination of the key allergen Sola l 7 in tomato seeds

A novel and disposable electrochemical biosensor for PCR-free and selective detection of Sola l 7, a non-specific lipid transfer protein (nsLTP) found in tomato seeds associated to severe symptoms of tomato-allergic patients, is reported in this work. The methodology involves the formation of DNA/RNA heterohybrids by sandwich hybridization of a specific fragment of the Sola l 7 allergen coding sequence with appropriate RNA probes designed and described for the first time in this work. Labeling was carried out with commercial antibodies specific to the heteroduplexes and secondary antibodies conjugated with HRP onto the surface of magnetic beads. Amperometric transduction was performed upon magnetic capture of the resulting magnetic bioconjugates on screen-printed electrodes using the system H2O2/HQ. A comparison of the sandwich hybridization format with a direct approach as well as between different labeling strategies was performed. The LOD value achieved was 0.2 pM (5 amol in 25 μL). The biosensor was successfully applied to the selective analysis of the targeted Sola l 7 specific region directly in just 100 ng of non-fragmented denatured genomic DNA extracted from tomato seeds.The financial support of the Spanish Ministerio de Economía y Competitividad Research Projects, CTQ2015-64402-C2-1-R, SAF2017-86483-R and the TRANSNANOAVANSENS Program from the Comunidad de Madrid (Grant P2018/NMT-4349) are gratefully acknowledged. M.F.B. is grateful to FCT grant SFRH/BPD/78845/2011,financed by POPH–QREN–Tipologia4.1–Formação Avançada, subsidized by Fundo Social Europeu and Ministério da Ciência, Tecnologiae Ensino Superior. The author M.A.P.B. is grateful to the authors J.M.R., M.F.B., S.C., J.M.P. for the scientific assistance and suggestions shared throughout the supervision of her Master’s project and Master’s thesis at University of Minho. The author M.A.P.B. also acknowledges the Department of Biology (DB) and the Centre of Molecular and Environmental Biology (CBMA) from University of Minho (UM), Braga,Portugal, by providing all the conditions leading to the Master's thesis in“Biophysics and Bionanosystems”. Financial support of M.A.P.B. forthis work was provided by a fellowship within the programme Erasmus+ scholarship/Portugal, which allowed performing the laboratorial work at the University Complutense of Madrid, Madrid, Spain. The author J.M.R. acknowledges CBMA-UM and DB-UM, Portugal, by the conditions provided. J.M.R. is also grateful to the Green Chemistry Laboratory (LAQV)–Research center Chemistry and Technology Network (REQUIMTE), and the Department of Chemistry and Biochemistry (DCB) from Faculty of Sciences, University of Porto(FCUP), Porto, Portugal, where currently he is researcher. J.M.R. acknowledges the financial support of the strategic programmes UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) and PTDC/SAUNUT/30448/2017 (POCI-01-0145-FEDER-030448) and M.F.B. the financial support of the projects PTDC/QUI-QAN/30735/2017 and UID/QUI/50006/2019, funded by national funds through Fundação para a Ciência e Tecnologia [Foundation for Science and Technology](FCT-I.P.)/Ministério da Ciência, Tecnologia e Ensino Superior [Ministry of Science, Technology and Higher Education] (MCTES), and Fundo Europeu de Desenvolvimento Regional [European RegionalDevelopment Fund] (FEDER), under the scope of the COMPETE2020–Programa Operacional Competitividade e Internacionalização[COMPETE2020–Competitiveness and InternationalizationOperational Program, POCI]. S.B. acknowledges the financial support from MINECO through the“Juan de la Cierva” program.info:eu-repo/semantics/publishedVersio

Immunologic responses to the major allergen of Olea Europaea in local and systemic allergic rhinitis subjects

Evaluate: the in vivo and in vitro responses to nOle e 1 in allergic rhinitis (AR) and local allergic rhinitis (LAR) patients sensitized to olive tree pollen (OL) confirmed by nasal allergen provocation test (NAPT). Methods: Twelve subjects with AR, 12 with LAR, and 12 subjects as control group (CG) were selected. Skin testing and NAPT with nOle e 1 were performed. ECP and tryptase were measured in nasal lavages before and after NAPT. Serum IgE to OL allergens were measured by ELISA. Basophil activation tests (BAT) with OL and nOle e 1 and dendritic cell maturation/proliferation studies were carried out. Results: All AR (12/12) and 10/12 (83%) of LAR had a +NAPT to nOle e 1. ECP levels in nasal lavages were significantly increased after NAPT in both AR and LAR compared with CG at 15 minutes (p<0.05). Serum IgE was positive only in AR. All AR had +BAT responses to OL and 10/12 to nOle e 1 (83%); 8/12 LAR (66.6%) had a +BAT with OL and 4/12 (33%) to nOle e 1, with only one subject of the control group with a +BAT to both OL and nOle e 1 (8%). Dendritic cell proliferation to nOle e 1 was increased in AR compared to LAR and CG (p=0.019 and p=0.001 respectively).Conclusion: Both AR and LAR had a similar in vivo response to nOle e 1 with release of inflammatory mediators. Specific basophil activation with OL and nOle e 1 was observed in LAR confirming previous data obtained with dust mites

A relevant IgE-reactive 28 kDa protein identified from Salsola kali pollen extract by proteomics is a natural degradation product of an integral 47 kDa polygalaturonase

[EN] A highly prevalent IgE-binding protein band of 28 kDa is observed when Salsola kali pollen extract is incubated with individual sera from Amaranthaceae pollen sensitized patients. By an immunoproteomic analysis of S. kali pollen extract, we identified this protein band as an allergenic polygalacturonase enzyme. The allergen, named Sal k 6, exhibits a pI of 7.14 and a molecular mass of 39,554.2 Da. It presents similarities to Platanaceae, Poaceae, and Cupressaceae allergenic polygalacturonases. cDNA-encoding sequence was subcloned into the pET41b vector and produced in bacteria as a His-tag fusion recombinant protein. The far-UV CD spectrum determined that rSal k 6 was folded. Immunostaining of the S. kali pollen protein extract with a rSal k 6-specific pAb and LC-MS/MS proteomic analyses confirmed the co-existence of the 28 kDa band together with an allergenic band of about 47 kDa in the pollen extract. Therefore, the 28 kDa was assigned as a natural degradation product of the 47 kDa integral polygalacturonase. The IgE-binding inhibition to S. kali pollen extract using rSal k 6 as inhibitor showed that signals directed to both protein bands of 28 and 47 kDa were completely abrogated. The average prevalence of rSal k 6 among the three populations analyzed was 30%, with values correlating well with the levels of grains/m(3) of Amaranthaceae pollen. Sal k 6 shares IgE epitopes with Oleaceae members (Fraxinus excelsior, Olea europaea and Syringa vulgaris), with IgE-inhibition values ranging from 20% to 60%, respectively. No IgE-inhibition was observed with plant-derived food extracts.This work was supported by grants SAF2011-26716 and SAF2014-53209-R from the Ministerio de Economia y Competitividad and RIRAAF Network RD12/0013/0015 from the ISCIII. R.B. was a fellow of the Ramon y Cajal program of the Ministerio de Economia y Competitividad (Spain). C.O-S. is supported by a contract of the Programa Operativo de Empleo Juvenil y la Iniciativa de Empleo Juvenil (YEI) with the participation of the Consejeria de Education, Juventud y Deporte de la Comunidad de Madrid y del Fondo Social Europeo.Mas-García, S.; Oeo-Santos, C.; Cuesta-Herranz, J.; Díaz-Perales, A.; Colás, C.; Fernández, J.; Barber, D.... (2017). A relevant IgE-reactive 28 kDa protein identified from Salsola kali pollen extract by proteomics is a natural degradation product of an integral 47 kDa polygalaturonase. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics. 1865(8):1067-1076. https://doi.org/10.1016/j.bbapap.2017.05.007S106710761865

Ash pollen immunoproteomics: Identification, immunologic characterization, and sequencing of 6 new allergens

Immunoproteomics, IgE-inhibition assays and cDNA-cloning reveals that ash and olive allergenic protein profiles are mostly equivalent, thus explaining their high cross reactivity. Our data suggest simplifying diagnosis of patients by using indistinctly ash or olive pollen