Submitted to: Journal of Agriculture and Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/1/2006
Publication Date: 4/17/2007
Citation: Fu, C.J., Jez, J.M., Kerley, M.S., Allee, G.L., Krishnan, H.B. 2007. Identification, characterization, epitope mapping, and three-dimensional modeling of the alpha-subunit of beta-conglycinin of soybean, a potential allergen for young pigs. Journal of Agriculture and Food Chemistry. 55:4014-4020. Interpretive Summary: Approximately 97 % of the soybean meal (SBM) produced in the US is used for animal feed, primarily in poultry, swine, and cattle diets. In the US, SBM accounts for 27% of the protein used in swine feeds. It has been shown that SBM can affect pig performance in the first few weeks following weaning and elicit specific antibodies in weaned piglets. However, these proteins have not been identified and characterized. In this study, we identified soybean beta-conglycinin alpha-subunit as being a potential allergen protein for weaning piglets. Three peptides located on the surface of the protein molecule have been found to be critical for the allergenicity. This study provides valuable information toward an understanding of the molecular basis of allergenicity. Information from this study may assist in construction of non-allergenic soybean proteins. Development of hypoallergenic soybeans will greatly enhance the nutritive value of soybean.
Technical Abstract: Soybean ranks among the eight most significant food allergens for humans. Soybean meal (SBM), the major by-product of soybean oil extraction, is the main protein source for swine diets globally. In the US, 8.6 million metric tons of SBM was used in swine rations in 2004. The pathological effect and immunological response of SBM feeding has been demonstrated in swine. In this study, we have utilized serum collected from piglets feed with SBM in immunoblot analysis to detect proteins that elicited antigenic response. We have identified soybean beta-conglycinin alpha-subunit as being a potential allergen for young piglets. Characterization of this protein indicated that deglycosylation and pepsin digestion did not eliminate immuno-reactivity of this protein. Epitope mapping utilizing planar cellulose supports technology (SPOT) showed three peptides spanning amino acids S185-R231 were critical for the allergenicity. Computer generated three-dimensional structure model of the alpha-subunit of beta-conglycinin indicated that the antigenic epitopes were located on the surface of the protein. Information from this study may assist in construction of recombinant non-allergenic soybean protein useable for both immunotherapy and the potential production of hypoallergenic soybean plants.