Beta(1,2)-xylose and alpha(1,3)-fucose residues have a strong contribution in IgE binding to plant glycoallergens.
Primary structures of the N-glycans of two major pollen allergens (Lol p 11 and Ole e 1) and a major peanut allergen (Ara h 1) were determined. Ole e 1 and Ara h 1 carried high mannose and complex N-glycans, whereas Lol p 11 carried only the complex. The complex structures all had a beta(1,2)-xylose linked to the core mannose. Substitution of the proximal N-acetylglucosamine with an alpha(1, 3)-fucose was observed on Lol p 11 and a minor fraction of Ole e 1 but not on Ara h 1. To elucidate the structural basis for IgE recognition of plant N-glycans, radioallergosorbent test analysis with protease digests of the three allergens and a panel of glycoproteins with known N-glycan structures was performed. It was demonstrated that both alpha(1,3)-fucose and beta(1,2)-xylose are involved in IgE binding. Surprisingly, xylose-specific IgE antibodies that bound to Lol p 11 and bromelain did not recognize closely related xylose-containing structures on horseradish peroxidase, phytohemeagglutinin, Ole e 1, and Ara h 1. On Lol p 11 and bromelain, the core beta-mannose is substituted with just an alpha(1,6)-mannose. On the other xylose-containing N-glycans, an additional alpha(1,3)-mannose is present. These observations indicate that IgE binding to xylose is sterically hampered by the presence of an alpha(1,3)-antenna.
van Ree
R
R
Department of Allergy, Central Laboratory of The Netherlands Red Cross Blood Transfusion Service, Academic Medical Centre, University of Amsterdam, 1066 CX Amsterdam, The Netherlands. r_van_ree@clb.nl
Cabanes-Macheteau
M
M
Akkerdaas
J
J
Milazzo
J P
JP
Loutelier-Bourhis
C
C
Rayon
C
C
Villalba
M
M
Koppelman
S
S
Aalberse
R
R
Rodriguez
R
R
Faye
L
L
Lerouge
P
P
D000485:Allergens / Q000378:metabolism*; D015153:Blotting, Western; D003429:Cross Reactions; D005643:Fucose / Q000378:metabolism*; D006031:Glycosylation; D006801:Humans; D007073:Immunoglobulin E / Q000096:biosynthesis / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D011134:Polysaccharides / Q000737:chemistry* / Q000276:immunology; D014994:Xylose / Q000378:metabolism*
D000485:Allergens; D010940:Plant Proteins; D011134:Polysaccharides; D005643:Fucose; D007073:Immunoglobulin E; D014994:Xylose