Comparison and In-Silico Modeling of Monoclonal Antibodies Recognizing the Immuno-Dominant Ana o 3 Cashew Nut Allergen

Authors: Mattison, Chris; VANT-HULL, BARRY - Contiguity Consulting; BREN-MATTISON, YVETTE - Biomed Bridge; Grimm, Casey

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary: Food allergies can be a significant medical and economic burden. Preventing accidental exposure to food allergens is essential and allergic reactions to cashew nuts are often severe. One of the dominant cashew allergens is called Ana o 3. Ana o 3 is a small protein composed of 2 smaller subunits held together by chemical bonds. The Ana o 3 protein remains soluble even after extensive heating of cashew nuts. The stability and solubility properties of Ana o 3 make it an excellent target for testing and detection of cashew allergens. Monoclonal antibodies are great tools for detection and characterization of food allergens. Several monoclonal antibodies that recognize Ana o 3 were developed, characterized, and their genes were sequenced. Some of the antibodies can distinguish between native, recombinant, and unfolded Ana o 3 proteins. These antibodies may enable new immuno-assays and the development of cashew allergen diagnostic tools that can be used to prevent accidental cashew allergen exposures.

Technical Abstract: Food allergies negatively affect quality of life and can be a significant medical burden. Allergic reactions to cashew nuts can often be severe and are rarely outgrown. The Ana o 3 protein is an immuno-dominant cashew allergen. Ana o 3 is a small 13kDa protein composed of 2 subunits held together by disulfide bonds that can be disrupted by treatment with reducing agents. The stability and solubility properties of Ana o 3 make it an excellent target for detection methods and tools. Several monoclonal antibodies targeted towards Ana o 3 were generated and 4 of them were characterized. All 4 of the monoclonal antibodies recognized both recombinant and native Ana o 3. One of the antibodies was specific for cashew nut extract, while 2 antibodies also recognized pistachio extract, and one of them also recognized pecan extract. Two of the antibodies likely recognized conformational epitopes as binding by these antibodies was disrupted after treatment of Ana o 3 with a reducing agent. In contrast, recognition of Ana o 3 by 2 of the antibodies was increased after reduction of Ana o 3, suggesting linear epitopes. The antibodies were sequenced, and potential epitopes and docking sites for each of the antibodies were predicted using in-silico modeling. This collection of antibodies represent useful reagents for the study and characterization of the Ana o 3 cashew nut allergen using cell based and immunoassay methods.