Location: Food Processing and Sensory Quality Research
2018 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 4 objectives, all of which fall under National Program 306, “Plant Product Development, Quality, and Marketability.” The project will address NP 306 Action Plan Component 1 Food: Problem Statement 1.A Define, Measure, Preserve/Enhance/Reduce Attributes that Impact Quality and Marketability, 1.B New Bioactive Ingredients and Functional Foods and 1.C New and Improved Food Processing Technologies. Under Objective 1, progress was made in showing that the allergenic potential of pistachio and cashew can be reduced by digestion with food-grade enzymes under ultrasound treatment. Also, naturally occurring polyphenolic compounds in pomegranate, blueberry, and concord grape juice were evaluated as allergen precipitation agents that can effectively reduce the reaction of allergy-related antibodies from the immune system, known as immunoglobulin E, to cashew allergens from cashew nut extracts. Under Objective 2, Immunoglobulin E is a type of antibody only found in mammals and sites where immunoglobulins E bind to multiple nut allergens have been identified and computationally predicted immunogenic peptides are being tested for Immunoglobulin E binding with serum antibodies from nut allergic patient blood. Cross-reactive binding sites between pathogenesis resistance-10 proteins, which are important for a type of food allergy that is caused by inhalation of pollen, from multiple nuts has been determined by different immunoassays. To meet the goals of Objective 2 and 4, cashew allergenic proteins (Ana o 1 and Ana o 3), that are known to cause allergic reactions in some individuals, were purified from cashew nut and will be used to generate antibodies in rabbits for further studies including the development of assays to identify these allergens in food systems. Peanut allergen Ara h 9 was expressed in recombinant form and purified for structural characterization and antibody production. Peanut allergenic proteins, Ara h 8.02 and Ara h 9, that are known to cause allergic reactions in some individuals, were purified from peanut seeds. Allergen purification, antibody production and immunologically-based assay development and improvement are constantly ongoing toward the detection of multiple nut allergens in foods. Under Objective 3, understanding genetic differences between plants may yield clues if pecan nuts from a particular plant have reduced Immunoglobulin E antibody binding and therefore cause less allergic reactivity. Therefore, the description and naming of genes discovered in a library of expressed pecan nut genes from pecan varieties such as the Sumner cultivar continues to be updated and compared to other cultivars to identify significant differences in pecan allergen sequences. Gene library sequence updates, corresponding protein library, along with physical protein separation methods may be used to characterize the timing and accumulation of allergens and other proteins during pecan development.
Accomplishments
1. Characterization and development of a food (peanut) as a pharmaceutical for the first time. ARS researchers at New Orleans, Louisiana, contributed to the detailed characterization and development of the first food allergy treatment/therapeutic drug for the treatment of peanut allergy, which has passed Phase 3 clinical trials and is close to market. Once this peanut oral immunotherapy (OIT) drug, which has been shown to desensitize allergic individuals, in much the same way as inhaled allergy shots, becomes available in the market, it will be the first food allergy treatment to be available on the market.
2. Development of antibodies and immunoassays against the major food allergens. The food industry, allergists, scientists and regulators need methods to detect allergenic proteins (allergens) in foods, on product lines, on surfaces, and pharmaceuticals. ARS researchers at New Orleans, Louisiana, have developed antibodies against specific food and purified allergenic proteins, which allow the development of various assays to detect and characterize the individual allergens. The purified allergens, antibodies and immunological methods are constant sources for funding, collaborations and technology transfer with various institutions that will use these tools to detect allergens in foods, such as regulators like FDA, who issue food recalls due to cross-contact of a non-allergenic food with allergens; companies that need to prevent cross-contamination of the products; and the pharmaceutical industries who want to normalize and perform detailed characterization of the allergen content of materials used for diagnostics and therapeutic treatments.
3. Development of a rapid method for purification of peanut and tree nut allergens. The food industry, regulatory agencies and other scientists and research partners are in search of rapid, large-scale production and detection of allergens. The current work on rapid, large-scale method for allergen purification, not only allows ARS researchers at New Orleans, Louisiana, to develop antibodies and immune assays, and to study the structure of individual allergic proteins, but allows other researchers to develop various types of assays that are relevant to their studies, such as characterization of the types and mechanisms of action of immune cells involved in the immunological responses in food allergy.
4. Identification of the immunoglobulin E binding sites of major nut allergens. The first step in an allergenic response is for the immune system molecules to bind to the protein causing the allergy. One method to identify biomarkers of allergic disease is to study the interaction of the immune system molecules, such as Immunoglobulin E, with the allergenic proteins to which they bind. The binding sites for the immunoglobulin E from hundreds of peanut and tree nut allergic individuals have been identified by ARS researches at the Southern Regional Research Center, in New Orleans, Louisiana, for multiple nut allergens. Identification of the sites on the allergenic protein where the immunoglobulin E binding enables researchers to design more targeted diagnostics and therapeutics protocols, which can result in better management of patient allergies and identification of antigenic proteins in food systems.
Review Publications
Chung, S., Mattison, C.P., Grimm, C.C., Reed, S.S. 2017. Simple methods to reduce major allergen Ara h 1 and Ana o 1/2 in peanut and cashew extracts. Journal of Food Science and Nutrition. 5:1065-1071.
Li, Y., Mattison, C.P. 2018. Polyphenol-Rich pomegranate juice reduces IgE binding to cashew nut allergens. Journal of the Science of Food and Agriculture. 98:1632-1638.
Vargas, A.M., Mahajan, A., Tille, K., Rans, T.S., Champoux, E., Grimm, C.C., Cottone, C.B., Riegel, C., Chial, H., Wilson, B., Mattison, C.P. 2018. Cross-reaction of recombinant termite (Coptotermes formosanus) tropomyosin with IgE from cockroach and shrimp allergic individuals. Annals of Allergy, Asthma & Immunology. 120(3):335-337.
Booth, W., Schlachter, C., Pote, S., Ussin, N., Mank, N., Klapper, V., Offermann, L., Tang, C., Hurlburt, B.K., Chruszcz, M. 2018. Impact of an N-terminal poly histidine tag on protein thermal stability. ACS Omega. 3:760-768.
Mattison, C.P., Jefferson, C.M., Gallao, M.I., De Brito, E. 2017. Effects of industrial cashew nut processing on anacardic acid content and allergen recognition by IgE. Food Chemistry. 240:370-376.
Adeseye, L.O., Cao, H., Maleki, S.J., Nayak, B. 2017. Shrimp tropomyosin retains antibody reactivity after exposure to acidic conditions. Journal of the Science of Food and Agriculture. https://doi:10.1002/jsfa.8221.
Cuadrado, C., Cheng, H., Sanchiz, A., Ballesteros, I., Easson, M.W., Grimm, C.C., Dieguez, C., Linacero, R., Burbano, C., Maleki, S.J. 2017. Influence of enzymatic hydrolysis on the allergenic reactivity of processed cashew and pistachio. Food Chemistry. https://doi.org/10.1016/j.foodchem.2017.08.120.
Lu, W., Negi, S.S., Schein, C.H., Maleki, S.J., Hurlburt, B.K., Braun, W. 2018. Distinguishing allergens from non-allergenic homologues using Physical–Chemical Property (PCP) motifs. Molecular Immunology. 99:1-8.
