Location: Soybean and Nitrogen Fixation ResearchTitle: Identification of immunogenic epitopes of two soybean glycinin proteins in chicken
Submitted to: Food and Agricultural Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/28/2019
Publication Date: 12/11/2019
Citation: Taliercio, E.W., Loveless, T.M. 2019. Identification of immunogenic epitopes of two soybean glycinin proteins in chicken. Food and Agricultural Immunology. 31:1, 75-83. https://doi.org/10.1080/09540105.2019.1700930.
Interpretive Summary: The protein content of soybeans comprises a significant amount of the value of the US soybean crop. Much of the soybean crop provides protein for animal feeds and any aspect of the protein the detract from it value as an animal feed reduce the value of soybean. The seed storage proteins glycinin and conglycinin account for 40% to 60% of soy protein. We have identified regions of two glycinin proteins that cause an immune response in chickens. An inappropriate immune response to proteins is a necessary but not sufficient to cause an animal to be allergic to soybean protein. Allergies to soybean seed storage proteins compromise the ability of the animal to grow when soybean proteins are present in feed. To develop a strategy to mitigate the allergic response of chickens to glycinin we have identified specific regions of the glycinin acidic and basic subunits that are consistently immunogenic. Identification of natural variants of these immunogenic regions or modifying these regions by molecular manipulations may provide insight into ways to improve the growth and egg production of chickens when fed soybean protein.
Technical Abstract: Soybean meal is an important protein supplement in chicken feed. Two seed storage proteins, glycinin and B-conglycinin account for most of the protein in soymeal. While a valuable source of protein, soybean has also been reported to be allergenic in some animals. These allergenic responses are reported to cause a growth lag when fed to young pigs and reduce carcass weight of broilers. Glycinin and conglycinin have been reported as allergens in multiple species, including humans. Allergic responses to proteins are caused by an inappropriate immune response to the protein. We have isolated antibodies from chicken eggs show that chickens mount an immunogenic response to glycinin. All three classes of chicken immunoglobulins, IgA, IgM and IgY bound glycinin protein. Using a tiled peptide array representing 2 different glycinin proteins, we show that there are immunogenic regions unique to each glycinin protein and antigenic epitopes bind unique repertoires of IgA, IgM and IgY. This knowledge can be used to identify variants of immunogenic glycinin epitopes to determine the role these immunogenic sites play in the allergic response of chickens to soy protein