Core α1,3-fucose is a key part of the epitope recognized by antibodies reacting against plant N-linked oligosaccharides and is present in a wide variety of plant extracts

Carbohydrates have been suggested to account for some IgE cross-reactions between various plant, insect, and mollusk extracts, while some IgC antibodies have been successfully raised against plant glycoproteins. A rat monoclonal antibody raised against elderberry abscission tissue (YZ1/12.23) and rabbit polyclonal antiserum against horseradish peroxidase were screened for reactivity in enzyme-linked immunosorbent assay against a range of plant glycoproteins and extracts as well as neoglycoproteins, bee venom phospholipase, and several animal glycoproteins. Of the oligosaccharides tested, Man(3)Xyl-FucGlcNAc(2) (MMXF3) derived from horseradish peroxidase was the most potent inhibitor of the reactivity of both YZ1/2.,23 and anti-horseradish peroxidase to native horseradish peroxidase glycoprotein, The reactivity of YZ1/2.23 and anti-horseradish peroxidase against Sophora japonica lectin was most inhibited by a neoglycoconjugate of bromelain glycopeptide cross-linked to bovine serum albumin, while the defucosylated form of this conjugate was inactive as an inhibitor, A wide range of plant extracts was found to react against YZ1/2.23 and anti-horseradish peroxidase, with particularly high reactivities recorded for grass pollen and nut extracts, All these reactivities were inhibitable with the bromelain glycopeptide/bovine serum albumin conjugate, Bee venom phospholipase and whole bee venom reacted weakly with YZ1/2.23 but more strongly with anti-horseradish peroxidase in a manner inhibitable with the bromelain glycopeptide/bovine serum albumin conjugate, while hemocyanin from Helix pomatia reacted poorly with YZ1/2.23 but did react with anti-horseradish peroxidase, It is concluded that the alpha 13-fucose residue linked to the chitobiose core of plant glycoproteins is the most important residue in the epitope recognized by the two antibodies studied, but that the polyclonal anti-horseradish peroxidase antiserum also contains antibody populations that recognize the xylose linked to the core mannose of many plant and gastropod N-linked oligosaccharides.