Location: Food Processing and Sensory Quality Research
2017 Annual Report
Objectives
Obective 1: Enable new commercial methods to reduce or eliminate the allergenic properties of peanut and tree nut products.
Objective 2: Integrate overall oral and food allergenic properties of native and recombinant allergens with cross-reactivity among nuts, between nuts and pollens, and with pre and postharvest processing.
Objective 3: Integrate allergenic properties and molecular changes with commercial tree nut development.
Objective 4: Enable new commercial immunoassays for detection of allergens in processed foods.
Approach
The immunoglobulin E (IgE) binding sites that are responsible for the symptoms of allergic disease and cross-reactivity among peanut, tree nut and pollen allergens will be identified with peptide microarray technology. The IgE epitopes will be modeled on the surface of allergen structures to identify location and common or cross-reactive sequences and structural regions of allergens among nuts and pollens. Simultaneously, peanuts, tree nuts or purified allergens thereof (recombinant or native) will be subjected to existing and novel processing techniques (i.e. heat, chemical and enzymatic treatment). New allergens or changes in allergenic properties of existing allergens due to the processing methods will be identified by immunoassays with serum (containing IgE antibodies) from peanut and or tree nut allergic individuals. Proteins found to be immunologically altered by processing will be assessed within the food matrix or they will be purified and analyzed for alterations in size, structure, digestibility, binding to various antibodies, including, serum IgE, known anti-processing reaction products, and allergen specific antibodies. The specific amino acid residues, or peptides thought to be modified during different processing events, and to contribute to altered allergenic properties will be identified by mass spectrometry. Understanding the molecular basis of processing-induced alterations of allergens with respect to the IgE binding sights will guide the development of processing technologies towards reduced allergenicity of nuts and products thereof. This knowledge will also contribute to the development of better detection tools and labeling practices for industry and regulatory agencies resulting in better protection of consumers. As a possible early interventional method to reduce the allergenic potential of nuts, the expression and accumulation patterns of allergens in a model tree-nut (pecan) will be studied under various conditions, which may allow interference with their accumulation in the future.
Progress Report
Progress was made on all four objectives of the research project, which is under National Program 306 titled Quality and Utilization of Agricultural Products.
To meet objective 1. Generally regarded as safe (GRAS), food safe, and naturally occurring redox-compounds continue to be tested for destabilization and lowering of immunoglobulin E (IgE) antibody binding to cashew allergens. Compounds that alter the structure, modify the amino acid sequence, or otherwise alter the appearance of nut allergens can be used to prevent recognition of these allergens by IgE antibodies, the primary immune agents of allergic reactions. Digestive enzyme inhibitors were attached to peanut allergens which were then put into the context of peanut extract and subjected to digestive enzymes. The resultant modified peanut allergens/extracts were found to be more resistant to digestion and or lower in allergenic capacity than native allergens. Enzymes from novel sources, such as Aspergillus, are being explored for their ability to digest cashew proteins.
To meet the goals of Objective 2, we continue to develop and optimize large scale, rapid purification methods of the native allergens such as nCor a 9, nCor a 8 and the 48 kDa glycoprotein from hazelnut, nAna o 3 from cashew, nJug r 2 and nJug r 2 LS from walnut and nAra h 6 from peanut and use them to generate antibodies (immunological molecules derived from blood). Almond allergen Pru du 1 is produced in bacteria and purified for structural characterization and antibody production. Immunoglobulin E (IgE) binding sites have been identified for multiple nut allergens and computationally predicted IgE binding peptides are being empirically tested for IgE binding with serum from nut allergic patients. Microarrays continue to be used to identify epitope maps of key peanut and tree nut allergens and compared with computationally predicted epitopes.
To meet Objective 3, the description and naming of genes found in the library of expressed pecan nut genes from the Sumner cultivar continues to be updated. Expression of allergen genes and genes involved in fatty acid metabolism during pecan nut development has been described. Identification continues of all the accumulated proteins in a developing pecan nut, using various technologies such as liquid chromatography-mass spectrometry that can physically separate the proteins and identify them based upon their unique masses.
To meet Objective 4, the major allergen proteins or peptides thereof from processed and unprocessed nuts have been identified and selected for purification and use in antibody production. Several antibodies have been made against peanut and walnut allergens and the immunoassays have been developed for testing antibody specificity and sensitivity.
Accomplishments
1. Development of antibodies against the major allergens of peanuts and tree nuts. Developing allergen specific antibodies addresses multiple goals of the project and subordinate projects. ARS scientists at New Orleans, Louisiana, have produced antibodies against specific nut allergens, which allows development of various assays to detect and characterize the individual allergens in food products used for oral immunotherapy and development of allergen reduction processes. The purified allergens, antibodies and immunological methods are constant sources for funded and unfunded collaborations and technology transfer with various universities such as University of North Carolina and companies such as Aimmune Therapeutics.
2. Development of a rapid method for purification and detection of hazelnut, peanut and walnut allergens. The food industry, regulatory agencies and other research partners are in search of rapid, large-scale production and detection of allergens. ARS scientist's research in New Orleans, Louisiana, provided tools for regulators and the food industry to detect and confirm the presence and the state of peanut and tree nut allergens in processed foods or on surfaces.
Review Publications
Chung, S., Reed, S.S., Zhang, D. 2016. Peanut allergens attached with p-aminobenzamidine are more resistant to digestion than native allergens. Polish Journal of Food and Nutrition Sciences. 7:1352-1363.
Yang, Y., Chen, Z., Hurlburt, B.K., Gui-Ling, L., Yong-Xia, Z., Dan-Xia, F., Hai-Wang, S., Min-Jie, C., Guang-Ming, L. 2017. Identification of triosephosphate isomerase as a novel allergen in octopus fangsiao. Molecular Immunology. 85:35-46.
Mahajan, A., Yousseff, L.A., Cleyrat, C., Grattan, R., Lucero, S., Mattison, C.P., Erasmus, F.M., Jacobson, B., Tapia, L., Hlavacek, W.S., Schuyler, M., Wilson, B.S. 2017. Allergen valency, dose and FcERI occupancy set thresholds for secretory responses to Pen a 1 and motivate design of hypoallergens. Journal of Immunology. 198:1034-1046. doi:10.4049/jimmunol.1601334.
Mattison, C.P., Grimm, C.C., Li, Y., Chidal, H.J., McCaslin, D.R., Chung, S., Bren-Mattison, Y., Wasserman, R.L. 2017. Identification and characterization of ana o 3 modifications on arginine-111 residue in heated cashew nuts. Journal of Agricultural and Food Chemistry. 65(2):411-420.
Mattison, C.P., Rai, R., Settlage, R.E., Hinchliffe, D.J., Madison, C.A., Bland, J.M., Brashear, S.S., Graham, C.J., Tarver, M.R., Florane, C.B., Bechtel, P.J. 2017. RNA-seq analysis of developing pecan (Carya illinoinensis) embryos reveals parallel expression patterns among allergen and lipid metabolism genes. Journal of Agricultural and Food Chemistry. 65:1443-1455. doi:10.1021/acs.jafc.6b04199.
Cabanillas, B., Crespo, J., Maleki, S.J., Rodriguez, J., Novak, N. 2016. Pin p 1 is a major allergen from Pine nut and the first food allergen described in the plant group of Gymnosperms. Journal of Agricultural and Food Chemistry. 210:70-77.
Comstock, S.S., Maleki, S.J., Teuber, S.S. 2016. Boiling and frying peanuts decreases soluble peanut (Arachis Hypogaea) allergens Ara h 1 and Ara h 2 but does not generate hypoallergenic peanuts. PLoS One. doi:10.1371/journal.pone.0157849.
Defreece, C.B., Cary, J.W., Grimm, C.C., Wasserman, R.L., Mattison, C.P. 2016. Treatment of cashew extracts with Aspergillopepsin reduces IgE binding to cashew allergens. Journal of Applied Biology & Biotechnology. 4(2):1-10.
Johnson, K., Williams, J., Maleki, S.J., Hurlburt, B.K., London, R., Mueller, G. 2016. Enhanced approaches for identifying Amadori products: application to peanut allergens . Journal of Agricultural and Food Chemistry. 64:1406-1413.
Liu, Q., Yang, Y., Maleki, S.J., Alcocer, M., Xu, S., Shi, C., Cao, M., Liu, G. 2016. Anti-food allergic activity of sulfated polysaccharide from gracilaria lemaneiformis is dependent on immunosuppression and inhibition of p38 mapk. Journal of Agricultural and Food Chemistry. 64:4536-4544.
Yang, Y., Zhang, Y., Liu, M., Maleki, S.J., Zhang, M., Liu, Q., Cao, M., Su, W., Liu, G. 2017. Triosephosphate isomerase and filamin C share common epitopes as novel allergens of Procambarus clarkii. Journal of Agricultural and Food Chemistry. 65:950-963.
