|Wasserman, R L - Allergy/immunology Research Center Of North Texas|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/16/2012
Publication Date: 2/23/2013
Citation: Mattison, C.P., Desormeaux, W.A., Grimm, C.C., Wasserman, R. 2013. Characterization of the effects of proteolysis and reduction on cashew allergens. Meeting Abstract. 133(2):AB115.
Technical Abstract: Resistance to digestive proteases is a common characteristic of food allergens. Among nut proteins, 2S albumins are refractory to digestion, and are potent food allergens. Allergic reactions to cashew have been described as more frequently severe than peanut reactions. The purpose of this study is to characterize the sensitivity of cashew proteins to proteolysis. Total cashew extracts and purified cashew allergens were subjected to proteolysis using varying protease-protein ratios and conditions. The effects of proteolysis were visualized by SDS-PAGE and immunoblotting with cashew allergic patient sera and anti-human IgE antibodies under reducing conditions. The proteins and peptides were evaluated by HPLC-coupled mass-spectrometry using an Agilent nano-LC fitted with Agilent 1200 nano-pumps and a 6500 Q-TOF LC. Spectral data from the analysis were evaluated with Spectrum Mill software to further compare and identify protein fragments. Protease concentration and prior treatment with reducing agent influenced the susceptibility of cashew proteins to proteolysis. Among cashew proteins, the 2S albumin Ana o 3 was more resistant to digestion by proteases, and digested Ana o 3 protein fragments retained IgE binding epitopes; however, reduction altered the sensitivity of Ana o 3 to protease digestion. Protease treatment can reduce binding of IgE from cashew allergic patients to cashew allergens, and disruption of disulfide bonds with reducing agents alters the sensitivity of cashew allergens to digestion. Our results indicate that processing steps including protein reduction and proteolysis could be used to reduce IgE binding to cashew allergens.