Structural analysis of N-glycans from allergenic grass, ragweed and tree pollens: Core alpha 1,3-linked fucose and xylose present in all pollens examined

The N-glycans from soluble extracts of ten pollens were examined. The pyrid ylaminated oligosaccharides derived from these sources were subject to gel filtration and reverse-phase HPLC, in conjunction with exoglycosidase diges ts, and in some cases matrix-assisted laser desorption-ionisation mass spec trometry. In comparison to known structures, it was possible to determine t he major structures of the N-glycans derived from Kentucky blue grass (Poa pratensis), rye (Secale cerale), ryegrass (Lolium perenne), short ragweed ( Ambrosia elatior), giant ragweed (Ambrosia trifida), birch (Betula alba), h ornbeam (Caprinus betulus), horse chestnut (Aesculus hippocastanum), olive (Olea europaea) and snake-skin pine (Pinus leucodermis) pollen extracts. Fo r grass pollens the major glycans detected were identical in properties to: [GRAPHICS] Grass pollens also contained some minor structures with one or two non-redu cing terminal N-acetylglucosamine residues. In the ragweed pollens, the maj or structures carried core alpha 1,3-linked fucose with or without the pres ence of xylose. In tree pollen extracts, the major structures were either x ylosylated, with or without fucose and terminal N-acetylglucosamine residue s, with also significant amounts of oligomannose structures. These results are compatible with the hypothesis that the carbohydrate structures are ano ther potential source of immunological cross-reaction between different pla nt allergens.