2 Glycobiology Division, Institute of Chemistry, University of Natural Resources and Applied Life Sciences (Universität für Bodenkultur), Muthgasse 18, A-1190, Vienna, Austria; and 3 FAZ-Floridsdorf Allergy Center, Vienna, Austria
Received on October 23, 2003; revised on December 19, 2003; accepted on January 11, 2004
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Abstract |
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Key words:
antiglycan antibody
/
core-1,3-fucose
/
cross-reactive carbohydrate determinant
/
insect glycoprotein
/
plant glycoprotein
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Introduction |
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More than 20 years ago, the existence of a cross-reactive carbohydrate determinant (CCD) was proposed based on the promiscuous binding of allergic patients' sera to periodate-sensitive, heat-stable epitopes in a variety of allergens (Aalberse et al., 1981). Although these criteria might well have been misleading, the hypothesis was later confirmed by increasingly sophisticated experiments. In 1988, a similarly cross-reactive rabbit antiserum was described (Faye and Chrispeels, 1988
) and in 1991 antihorseradish peroxidase (HRP) serum was shown to bind to complex type plant N-glycans containing xylose and core
1,3-fucose (Kurosaka et al., 1991
).
Not much later, Tretter et al. (1993) reported that due to the presence of core
1,3-fucose, plant N-glycans can bind IgE from many bee venom allergic patients. In this and other studies, bromelain glycopeptides were employed, and the relative lability of the
1,3-fucosyl linkage allowed the preparation of nonfucosylated glycopeptides, which could be tested in antibody-binding assays. Because these defucosylated glycopeptidesstill containing xylosewere unable to bind IgE from bee venom allergic individuals, we concluded that the core
1,3-fucose is the key structural element for antibody binding. Identical results were obtained with patients sensitized against tomato, celery, and other allergens (Foetisch et al., 1999
, 2001
; Petersen et al., 1996
; Westphal et al., 2003
). However, other important allergens, such as Ara h 1, Ole e 1, or a vicillin-like 48-kDa protein from hazelnut, to which anti-CCD IgE binds, have been found to contain primarily structures with only xylose (Kolarich and Altmann, 2000
; Müller et al., 2000
; van Ree et al., 2000
). Strong evidence in favor of the assumption that xylose also plays a role as (part of) a glyco-epitope came from a report on the fractionation of a polyclonal anti-HRP antiserum into a fucose-specific and a xylose-specific pool using immobilized honeybee phospholipase (Faye et al., 1993
). Unfortunately there was no well-defined glycoprotein containing xylose only that would have helped assess the specificity of these fractions or the specificity of patients' sera IgE. Ascorbic acid oxidase from zucchini, occasionally used for that purpose (Batanero et al., 1999
), definitely also contains fucose (Altmann, 1998
), whereas not necessarily all of the (partially very complex) structures occuring on hemocyanin from Helix pomatia have so far been elucidated (Lommerse et al., 1997
).
Thus, although it is clear that CCDs essentially means complex type plant N-glycans (Foetisch and Vieths, 2001), the relative contributions of fucose and xylose or of other structural features to antibody binding are still unclear. Likewise, a sometimes postulated supportive role of the protein backbone for antibody binding has never been proven or disproven.
The biological significance of carbohydrate determinants in food, insect venom, or pollen allergies, however, is to a much higher degree unclear and topic of a current debate (Foetisch and Vieths, 2001; Foetisch et al., 2003
; Hemmer et al., 2001
; van der Veen et al., 1997
). In many cases, anti-CCD IgE antibodies do not appear to trigger clinical symptoms (van Ree et al., 1997
; van Ree, 2002
). This is contrasted by positive histamine release tests with some patients' sera (Bublin et al., 2003
; Foetisch et al., 1999
, 2003
; Westphal et al., 2003
) and by cases of patients with symptoms elicited by foods in the absence of detectable amounts of IgE against peptide epitopes (Foetisch et al., 2003
). The various aspects associated with carbohydrate determinants as allergens, for example, the discrepancies between serum tests, histamine release, skin tests, and finally clinical symptoms, have recently been reviewed and need not to be recapitulated here (van Ree, 2002
). Clearly, CCDs play a role as a source of false-positive serum test results in allergy diagnosis as the presence of anti-CCD IgE often has no clinical consequences (Hemmer et al., 2001
; Mari et al., 1999
; van Ree, 2002
). In keeping with earlier reports (Foetisch et al., 1999
; Tretter et al., 1993
), a recent survey indicated 23% of 1831 patients have anti-CCD IgE (Mari, 2002
). The criterion for CCD reactivity was a positive enzyme-linked immunosorbent assay (ELISA) and a negative skin prick test against bromelaina plant glycoprotein with one complex type N-glycan lacking the
1,3-mannose (Ishihara et al., 1979
). Although this report impressively demonstrates the dimension of the problem, it also demonstrates the need for structurally defined and more easily applicable test antigens for the detection of antiglycan IgE antibodies.
Here we report on the synthesis and characterization of a glyco-modified human glycoprotein. Various glycoforms of human transferrin (Tf) with or without xylose, fucose, terminal GlcNAc, or 3-linked mannose have been prepared (Figure 1), and their ability to bind anti-CCD IgG and anti-CCD IgE from patients' sera was tested.
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Results |
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Both Xyl-T and Fuc-T could be obtained in a form concentrated enough to allow an essentially complete conversion of several mg of GnGn-Tf to GnGnX-Tf or GnGnF-Tf, respectively (Figures 1 and 2). Initially we had problems to achieve complete fucosylation, and speculations were made as to a restricted access of the transferase to the attachment on the native Tf. However, the problem could be overcome by adding aliquots of the donor sugar GDP-fucose over the course of incubation; thus, the incomplete conversion was due the instability of GDP-fucose rather than a decreasing activity of the enzyme. Although the Pichia strain used (GS115) secretes detectable amounts of protease (Brierley, 1998) the final products were essentially intact with only a small amount of a fragment band at 41.3 kDa (Figure 4D).
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Recent reports would suggest that the N-glycans recognized by anti-CCD did not contain terminal GlcNAc (Foetisch and Vieths, 2001; van Ree et al., 2000
; Wilson et al., 1998
). In addition, preliminary results of anti-HRP western blots with fucosylated and xylosylated forms of GnGn-Tf with or without prior hexosaminidase indicated that in fact the terminal GlcNAc residues had a weakening effect on antibody binding. Therefore the primary transferase products were digested with hexosaminidase to finally yield the glyco-variants MM-, MMX-, MMF-, and MMXF-Tf. The success of the various modification steps was finally verified by mass spectrometry (MS) of the glycopeptides around Asn 630 (Figure 3). The glycopeptide 421433 could not be observed in the matrix-assisted laser desorption ionization (MALDI) MS spectrum. It should be noted that the glycosidases used (except the
-mannosidase) were not of plant origin, thus avoiding any glyco-contamination from this source.
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An ELISA titration of anti-HRP using MMX-, MMF-, and MMXF-Tf as antigens revealed strikingly similar antibody titers against each of the three glycoforms. This could imply that this serum consists of one population of antibodies that although polyclonal all bind with similar affinity to each of the three glycoforms. However, subsequent inhibition studies revealed the opposite. Binding of anti-HRP to MMX-Tf could not be inhibited by MMF-Tf and binding to MMF-Tf not by MMX-Tf (Table I). In contrast, binding of the rat monoclonal antibody YZ1/2.23 to MMX-Tf and MMF-Tf could be mutually cross-inhibited by MMX- and MMF-Tf (Table I). It is noteworthy that the absorbance measured for binding to MMX-Tf was only half that obtained with MMF-Tf. Apparently, YZ1/2.23 bears a paratope that covers both the fucosyl and the xylosyl residues, but with fucose contributing more to binding strength. Thus YZ1/2.23 cannot be used to discriminate between fucosylated or xylosylated glycoproteins (Figure 4C).
In previous work, defucosylation of bromelain glycopeptides led to a drastic decrease in their antibody-binding capacity, indicating negligible antibody binding by the glycopeptide carrying solely xylose (Petersen et al., 1996; Tretter et al., 1993
; Wilson et al., 1998
). The data presented here appear to contradict these earlier reports, because binding to MMX-Tf was displayed by both anti-HRP and YZ1/2.23 (Figure 4 and Table I). However, in the previous studies, defucosylated bromelain, which has a MUX structure, was used. Comparison of the inhibitory potency of MMX and MUX for anti-HRP binding to MMX-Tf revealed the significance of the
1,3-mannosyl residue (Table I and also Figure 4). In other words, although the MUXF structure of bromelain glycopeptides is suitable for measuring antifucose antibodies (Wilson et al., 1998
), it does not appear to be useful for detecting antixylose antibodies.
Up to that point, only Tf glycoforms had been used as coat antigens. A natural glycoprotein might contain additional structural features, and thus we chose oil seed rape pollen (OSR) extract as more natural example to explore the natural history of anti-CCD antibodies. Essentially complete inhibition of anti-HRP binding to OSR could be obtained by MMXF-Tf at a concentration ranging from 1 to 100 µg/ml (Table I). HRP itself, however, inhibited more effectively on a weight per volume basis by a factor of about 30 to 60 (Table I). Considering at least 7 N-glycans per molecule of HRP with a mass of 45 kDa for HRP and 1.6 fucosylated glycans per molecule of Tf with a mass of 70 kDa, the difference shrinks, in molar terms, to between 4 and 9. This still significant difference in inhibitory potency could point to a contribution to antibody binding of the peptide regions in the neighborhood of the N-glycan, which of course differ between transferrin and HRP to which the antibody was actually raised. It could, however, simply reflect the difference in valency of these two glycoproteins, which is known to be a critical factor for binding strength of carbohydrate epitopes (Welply et al., 1994; Yi et al., 1998
). Finally it should be mentioned that GnGnXF-Tf had only negligible inhibitory potency for anti-HRP (Table I).
Detection and characterization of IgE against CCDs
Finally, a small panel of allergic patients' sera was subject to measurement of specific IgE binding to the different Tf glycoforms. All of the bee and wasp venom double-positive patients' sera showed reaction with the fucosylated transferrins MMF and MMXF (the latter, however, could not be tested with all sera). Many sera of this group gave especially high readings in ELISA (Figure 5A). Similarly, most of the rape pollen reactive sera also reacted with MMF and MMXF, which corroborates the recent conclusion that OSR reactivity is in many cases due to anti-CCD IgE, whereby rape pollen itself had not necessarily been the elicitor of this immune response (Hemmer et al., 2001). None of the sera in these groups bound with MMX. In the case of the insect venom allergic patients, this is not surprising. However, these sera also bound stronger to MMXF-Tf which was, in addition to being fucosylated, also xylosylated (Figure 5B).
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To our surprise and disappointment, none of the sera recognized MMX to a significant degree, with the exception of one heavily atopic patient whose serum reacted strongly even with MM-Tf. As this contrasts the results obtained for rabbit anti-HRP, we assume the lack of MMX-binding by human IgE to be the result of our serum selection rather than of a general invisibility of xylose for the human immune system. This is especially obvious for the insect venom group because insect glycoproteins do not contain xylose. Future studies with panels of patients allergic against primarily xylosylated allergens, such as olive pollen, hazelnut, or peanut, may clarify this point.
Recently, human IgG levels against CCD structures have been measured using honeybee venom phospholipase and Helix pomatia hemocyanin as core 1,3-fucosylated probe and as ß1,2-xylosylated standards, respectively (Bardor et al., 2002
). We compared the results obtained with the glycomodified Tfs with these naturally available probes. The results obtained with phospholipase and MMF- or MMXF-Tf indeed were in agreement. The ELISA readings, however, were generally lower with phospholipase with the exception of a few sera where especially high values for phospholipase suggested the presence of antiprotein IgE (Figure 6A). In other words, because the phospholipase polypeptide is the major allergen of bee venom, it cannot at all be regarded as a reliable probe for the measurement of anti-CCD antibodies. Hemocyanin, like MMX-Tf, was not bound significantly by any of the sera (data not shown).
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Discussion |
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Because the glycans on Tf, especially in the GnGn but also in the galactosylated form, are substrate for a variety of yet other glycosyltransferases, the same approach could obviously also be chosen for other glycodeterminants. In addition to antibody binding, the reactivity with animal lectins could be studied with such Tf glycoforms using western blot, ELISA, or immunohistochemistry with Tf-specific antibodies. Indeed, a Drosophila lectin binding core 1,3-fucose has been characterized using MMF-Tf prepared in this laboratory (Bouyain et al., 2002
).
In this study the specificity of polyclonal rabbit sera, especially of an anti-HRP serum and of a rodent monoclonal antibody were studied. The latter, YZ1/2.23, exhibited a somewhat complicated epitope structure where both fucose and xylose residues play roles for antibody binding. In contrast, anti-HRP appears to consist of two distinct populations with paratopes either binding fucosylated or xylosylated glycans. Reflecting the absence of xylose in insect glycoproteins, the antihoneybee serum only bound to core 1,3-fucosylated transferrin.
The results obtained for GnGnF and GnGnXF show that the mere presence of core 1,3-fucose is, however, not the only criterion for binding of these antibodies. The CCD-epitope can be hidden by additional modifications of the N-glycan as was already suggested as an explanation for the low anti-HRP binding of tree pollens, which predominantly contain N-glycans with terminal GlcNAc residues (Wilson et al., 1998
, 2001
; Wilson and Altmann, 1998
).
Steric factors may also influence antibody binding. In western blots, it appeared that the proteolytic fragment generated during enzymatic modifications of Tf binds slightly stronger than the full-length Tf (Figure 3). A similar albeit contrary observation is made with honeybee phospholipase as compared to the much less abundant hyaluronidase (Hemmer et al., 2003). Unfortunately, such effects of steric presentation on antibody binding are difficult to discern experimentally.
Another modulator of binding strength beyond glycan structure is the valency of the glyco-antigen. We suggest that this valency factor explains the difference in inhibitory potency of MMXF-Tf and HRP. Polyvalency is an important factor for the ability to trigger physiological reactions of effector cells in allergy. Because Tf is divalent it can be expected to be effective in biological test systems, such as histamine release by granulocytes.
The analysis of the specificity of patients' sera revealed once again the importance of core 1,3-linked fucose. This had to be expected in the bee and wasp venom reactive group, but it was also observed for patients with OSR and multiple pollen reactivity. Remarkably, however, MMXF-Tf consistently gave higher ELISA readings than MMF-Tf, even though no patient in our test groups exhibited significant binding with merely xylosylated glycans.
It should be emphasized that the biosynthetic glyco-antigens used here are more reliable probes for anti-CCD IgE than, say, honeybee phospholipase, which also contains a number of highly important peptide epitopes. In the near future, larger numbers of patients' sera shall be analyzed using the glycomodified transferrins with methods more suitable for IgE quantitation than ELISA. Apart from the maybe academic question of whether there are xylose-reactive patients, a major issue will be to render allergy diagnosis more reliable by allowing discrimination between IgE binding to peptide or to carbohydrate epitopes. Although the overall prevalence of anti-CCD antibodies in our patients' sera was lower than that reported by others (Mari, 2002), our data suggest that such antibodies may be commonly found in patients with multiple sensitization to many different allergens. However, there is no obvious correlation between anti-CCD titers as measured with, for example, MMXF-Tf and total IgE levels (Figure 6B), which contradicts the view that CCD reactivity is merely a nonspecific phenomenon observed in highly atopic patients.
Especially in the case of insect venom and food allergy, both including a certain risk for fatal or nearly fatal reactions, it appears appropriate to develop tests that can result in reassuring patients where a positive laboratory result is merely caused by CCDs, which supposedly have no clinical significanceat least in the absence of anti-peptide IgE against the respective allergen.
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Materials and methods |
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GDP-fucose was purchased from Sigma-Aldrich, and UDP-xylose was obtained from CarboSource Services at the University of Georgia. The monoclonal antibody YZ1/2.23, raised against elderberry abscission tissue, was a gift of Dr. Daphne Osborne (Open University) and David Ashford (University of York). Polyclonal anti-HRP serum from rabbit, antibee venom serum from rabbit, and the respective second antibodies have been described before (McManus et al., 1988; Wilson et al., 1998
).
Sera were collected from patients undergoing routine allergy testing for inhalant or insect venom allergy. Patients with inhalant allergy were skin-prick tested with common inhalant allergens, including pollens (hazel, alder, birch, grass, rye, ash, plantain, nettle, mugwort, ragweed, OSR, plane tree), house dust mites, animal danders (cat, dog, horse, guinea pig), molds (Cladosporium, Alternaria, Penicillium), and rubber latex (all Soluprick, ALK, Denmark). Insect venom allergy was confirmed by positive radioallergosorbent test and subsequent skin testing.
Three groups of sera were used: (1) Sera from patients suffering from pollen allergy that according to radioallergosorbent and skin-prick test were sensitized to a narrow range of pollen allergens only, for instance, birch and other Fagales pollen only (n = 20) and grass/rye pollen only (n = 24); all patients from this group also had a positive radioallergosorbent test to the respective allergen; 4 of the 44 patients had a weakly positive skin test but negative serology to one of the tested indoor allergens; (2) sera from patients with multiple pollen sensitization, for instance, sensitization to at least 4 different pollen species (n = 41); patients from this group had multiple positive radioallergosorbent test to pollen allergens, although not all allergens reacting positively in the skin test have been tested by serology; 26 of the patients were also sensitized to one or more of the indoor allergens; (3) preselected sera that were assumed to contain anti-CCD IgE, such as those reacting with HMW glycoallergens in OSR (Focke et al., 1988) (n = 9) or those exhibiting cross-reactivity with bee and wasp venom glycoallergens (Hemmer et al., 2001
, unpublished data) (n = 7).
Preparation of glycomodified Tfs
Ten milligrams of human apo-Tf (Sigma-Aldrich) was treated for 16 h with 100 mU neuraminidase in 0.5 ml 50 mM sodium acetate buffer at pH 5.0 at 37°C. Subsequently, 4.2 U ß-galactosidase from Aspergillus oryzae (Zeleny et al., 1997) was added, and the sample was incubated overnight. The integrity of the resultant GnGn-transferrin was checked by sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDSPAGE) and the N-glycans were analysed as will be described.
For xylosylation, GnGn-Tf (5 mg in a final volume of 1.6 ml) was incubated with 4 µmol UDP-xylose and 13 mU Xyl-T (in 25 mM 2(N-morpholino)ethanesulfonic acid, pH 7.0) at 16°C for 48 h. For fucosylation, GnGn-Tf (2 mg in a final volume of 0.8 ml containing 20 mM MnCl2) was incubated with 2.8 µmol GDP-fucose (added in three aliquots over time) and 0.6 mU Fuc-T (dissolved in 25 mM 2(N-morpholino)ethanesulfonic acid, pH 6.8) at 25°C for 48 h. A doubly modified glycoform, GnGnXF-Tf, was obtained by fucosylation of GnGnX-Tf.
To remove the terminal N-acetylglucosamine residues, solutions of GnGn-, GnGnX-, GnGnF-, and GnGnXF-Tfs were diluted threefold with 50 mM sodium citrate buffer of pH 5.0 and digested with ß-N-acetyl-glucosaminidase (0.5 mU/mg Tf). For the preparation of glycoforms lacking the 1,3-mannosyl residue, 0.45 mg MM- and MMX-Tf were digested for 24 h at 37°C with 20 mU jack bean
-mannosidase in the buffer containing 0.1 mM ZnCl2.
Analytical methods
The structures of the N-glycans on the various Tf glycoforms were verified in two ways. (1) In the first approach, 10 µg glycoproteins were digested for 4 h at 37°C with 0.5 µg pepsin (Sigma-Aldrich) in 30 µl 5% formic acid. Then this solvent was evaporated, and the samples were deglycosylated with peptide:N-glyosidase A described (Kolarich and Altmann, 2000). Oligosaccharides were isolated and analysed by MALDI MS on a linear time-of-flight instrument as described (Kolarich and Altmann, 2000
). (2) Alternatively, glycoproteins were subjected to SDSPAGE, and bands were excised, S-alkylated, and digested with described (Katayama et al., 2001
; Kolarich and Altmann, 2000
). The (glyco-)peptides were analyzed by MALDI MS on a Waters-Micromass Q-TOF GLOBAL system using
-cyano-4-hydroxycinnamic acid as the matrix.
Western blot
Tf glycoforms (0.1 µg) were separated by SDSPAGE and electroblotted to a nitrocellulose membrane. The membrane was blocked with 3% nonfat milk in 10 mM TrisHCl, pH 7.5, 150 mM NaCl, 0.1% Tween and subsequently incubated for 1 h with rabbit anti-HRP or antibee venom serum diluted 1:2000. After washing in Tris-buffered saline, alkaline phosphataseconjugated anti-rabbit antibody at a dilution of 1:2000 was added, and bands were stained for 30 min with 5-bromo-4-chloro-3-indolyl phosphate and nitro blue tetrazolium.
IgG ELISA
Tf glycoforms at a concentration of 5 µg/ml or OSR at a protein concentration of 1 µg/ml was used for coating ELISA well plates (Nunc maxisorp) for 1 h at 37°C in 0.1 M sodium carbonate buffer, pH 9.6. After the washing and blocking steps, plates were incubated for 1 h at 37°C with either anti-HRP diluted 1:20,000 or YZ1/2.23 diluted 1:40,000. The subsequent steps were performed as described previously (Wilson et al., 2001).
For inhibition ELISA, sera were preincubated for 1 h at 37°C with different glycoproteins at different concentrations.
IgE ELISA
Microtiter plates were coated with Tf glycoforms overnight at 4°C but otherwise as described. The plates were washed twice with phosphate-buffered saline (PBS) containing 0.05% Tween 20 and blocked with PBS containing 1% bovine serum albumin for 2.5 h at room temperature. The plates were then incubated overnight at 4°C with allergic patients' sera diluted 1:10 with PBS. After washing the plates five times with Tween-20 containing PBS, anti-human IgEalkaline phosphatase conjugate (Pharmingen, San Diego) diluted 1:2000 with PBS containing 0.05% bovine serum albumin was added, and the plates were incubated first for 1 h at 37°C and then for 30 min at 4°C. Plates were again washed five times and then stained with p-nitrophenyl phosphate dissolved to 1 mg/ml in 0.1 M diethanolamine of pH 9.7. The optical density at 405 nm was read after 2 h.
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Acknowledgements |
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Footnotes |
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Abbreviations |
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References |
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Altmann, F. (1998) Structures of the N-linked carbohydrate of ascorbic acid oxidase from zucchini. Glycoconj. J., 15, 7982.[CrossRef][ISI][Medline]
Altmann, F., Staudacher, E., Wilson, I.B.H., and März, L. (1999) Insect cells as hosts for the expression of recombinant glycoproteins. Glycoconj. J., 16, 109123.[ISI][Medline]
Bardor, M., Faveeuw, C., Fitchette, A.C., Gilbert, D., Galas, L., Trottein, F., Faye, L., and Lerouge, P. (2002) Immunoreactivity in mammals of two typical plant glyco-epitopes, core (1,3)-fucose and core xylose. Glycobiology, 13, 427434.[ISI][Medline]
Batanero, E., Crespo, J.F., Monsalve, R.I., Martin-Esteban, M., Villalba, M., and Rodriguez, R. (1999) IgE-binding and histamine-release capabilities of the main carbohydrate component isolated from the major allergen of olive tree pollen, Ole e 1. J. Allergy Clin. Immunol., 103, 147153.[ISI][Medline]
Bencúrová, M., Rendic, D., Fabini, G., Kopecky, E.M., Altmann, F., and Wilson, I.B.H. (2003) Expression of eukaryotic glycosyltransferases in the yeast Pichia pastoris. Biochimie, 85, 413422.[CrossRef][ISI][Medline]
Bouyain, S., Silk, N.J., Fabini, G., and Drickamer, K. (2002) An endogenous Drosophila receptor for glycans bearing 1,3-linked core fucose residues. J. Biol. Chem., 277, 2256622572.
Brierley, R.A. (1998) Secretion of recombinant human insulin-like growth factor I (IGF-I). Methods Mol. Biol., 103, 149177.[Medline]
Bublin, M., Radauer, C., Wilson, I.B.H., Kraft, D., Scheiner, O., Breiteneder, H., and Hoffmann-Sommergruber, K. (2003) Cross-reactive N-glycans of Api g 5, a high molecular weight glycoprotein allergen from celery, are required for immunoglobulin E binding and activation of effector cells from allergic patients. FASEB J., 17, 16971699.
Faveeuw, C., Mallevaey, T., Paschinger, K., Wilson, I.B.H., Fontaine, J., Mollicone, R., Oriol, R., Altmann, F., Lerouge, P., Capron, M., and Trottein, F. (2003) Schistosome N-glycans containing core 3-fucose and core ß2-xylose epitopes are strong inducers of Th2 responses in mice. Eur. J. Immunol., 33, 12711281.[CrossRef][ISI][Medline]
Faye, L. and Chrispeels, M.J. (1988) Common antigenic determinants in the glycoproteins of plants, molluscs and insects. Glycoconj. J., 5, 245256.[ISI]
Faye, L., Gomord, V., Fitchette-Laine, A.C., and Chrispeels, M.J. (1993) Affinity purification of antibodies specific for Asn-linked glycans containing 1
3 fucose or ß1
2 xylose. Anal. Biochem., 209, 104108.[CrossRef][ISI][Medline]
Focke, M., Hemmer, W., Hayek, B., Götz, M. and Jarisch, R. (1998) Identification of allergens in oilseed rape (Brassica napus) pollen. Int. Arch. Allergy Immunol., 117, 105112.[CrossRef][ISI][Medline]
Foetisch, K. and Vieths, S. (2001) N- and O-linked oligosaccharides of allergenic glycoproteins. Glycoconj. J., 18, 373390.[CrossRef][ISI][Medline]
Foetisch, K., Altmann, F., Haustein, D., and Vieths,S. (1999) Involvement of carbohydrate epitopes in the IgE response of celery-allergic patients. Int. Arch. Allergy Immunol., 120, 3042.
Foetisch, K., Son, D.Y., Altmann, F., Aulepp, H., Conti, A., Haustein, D., and Vieths. S. (2001) Tomato (Lycopersicon esculentum) allergens in pollen-allergic patients. Eur. Food Res. Technol., 213, 259266.[CrossRef][ISI]
Foetisch, K., Retzek, M., Westphal, S., Lauer, L., Altmann, F., Kolarich, K., Scheurer, S., and Vieths, S. (2003) Biological activity of IgE specific for cross-reactive carbohydrate determinants (CCD) J. Allergy Clin. Immunol., 111, 889896.[CrossRef][ISI][Medline]
Haslam, S.M., Morris, H.R., and Dell, A. (2001) Mass spectrometric strategies: providing structural clues for helminth glycoproteins. Trends Parasitol., 17, 213235.
Hemmer, W., Focke, M., Kolarich, D., Wilson, I.B.H., Altmann, F., Wöhrl, S., Götz, M., and Jarisch, R. (2001) Antibody binding to venom carbohydrates is a frequent cause for double-positivity of honeybee and yellow jacket venom in patients with stinging insect allergy. J. Allergy Clin. Immunol., 108, 10451052.[CrossRef][ISI][Medline]
Hsu, T.A., Takahashi, N., Tsukamoto, Y., Kato, K., Shimada, I., Masuda, K., Whiteley, E.M., Fan, J.Q., Lee, Y.C., and Betenbaugh, M.J. (1997) Differential N-glycan patterns of secreted and intracellular IgG produced in Trichoplusia ni cells. J. Biol. Chem., 272, 90629070.
Ishihara, H., Takahashi, N., Oguri, S., and Tejima, S. (1979) Complete structure of the carbohydrate moiety of stem bromelain. An application of the almond glycopeptidase for structural studies of glycopeptides. J. Biol. Chem., 254, 1071510719.[Abstract]
Katayama, H., Nagasu, T., and Oda, Y. (2001) Improvement of in-gel digestion protocol for peptide mass fingerprinting by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Rapid Commun. Mass Spectrom., 15, 14161421.[CrossRef][ISI][Medline]
Kolarich, D. and Altmann, F. (2000) N-glycan analysis by matrix assisted laser desorption/ionisation mass spectrometry of electrophoretically separated non-mammalian proteins. Application to peanut allergen Ara h 1 and olive pollen allergen Ole e 1. Anal. Biochem., 285, 6475.[CrossRef][ISI][Medline]
Kubelka, V., Altmann, F., Staudacher, E., Tretter, V., März, L., Hård, K., Kamerling, J.P., and Vliegenthart, J.F.G. (1993) Primary structures of the N-linked carbohydrate chains from honeybee venom phospholipase A2. Eur. J. Biochem., 213, 11931204.[Abstract]
Kubelka, V., Altmann, F., and März, L. (1995) The asparagine-linked carbohydrate of honeybee venom hyaluronidase. Glyconj. J., 12, 7783.
Kurosaka, A., Yano, A., Itoh, N., Kuroda, Y., Nakagawa, T., and Kawasaki, T. (1991) The structure of a neural specific carbohydrate epitope of horseradish peroxidase recognized by anti-horseradish peroxidase antiserum. J. Biol. Chem., 266, 41684172.
Lerouge, P., Cabanes-Macheteau, M., Rayon, C., Fitchette-Lainé, A.C., Gomord, V., and Faye, L. (1998) N-glycoprotein biosynthesis in plants: recent developments and future trends. Plant Mol. Biol., 38, 3148.[CrossRef][ISI][Medline]
Lommerse, J.P., Thomas-Oates, J.E., Gielens, C., Preaux, G., Kamerling, J.P., and Vliegenthart, J.F. (1997) Primary structure of 21 novel monoantennary and diantennary N-linked carbohydrate chains from -hemocyanin of Helix pomatia. Eur. J. Biochem., 249, 195222.[Abstract]
Mari, A. (2002) IgE to cross-reactive carbohydrate determinants: analysis of the distribution and appraisal of the in vivo and in vitro reactivity. Int. Arch. Allergy Immunol., 129, 286295.[CrossRef][ISI][Medline]
Mari, A., Iacovacci, P., Afferni, C., Barletta, B., Tinghino, R., Di Felice, G., and Pini, C. (1999) Specific IgE to cross-reactive carbohydrate determinants strongly affect the in vitro diagnosis of allergic diseases. J. Allergy Clin. Immunol., 103, 10051011.[ISI][Medline]
McManus, M.T., McKeating, J., Secher, D.S., Osborne, D.J., Ashford, D., Dwek, R.A., and Rademacher, T.W. (1988) Identification of a monoclonal antibody to abscission tissue that recognises xylose/fucose-containing N-linked oligosaccharides from higher plants. Planta, 175, 506512.[ISI]
Müller, U., Lüttkopf, D., Hoffmann, A., Petersen, A., Becker, W.M., Schocker, F., Niggemann, B., Altmann, F., Kolarich, D., and Vieths, S. (2000) Allergens in native and roasted hazelnuts (Corylus avellana) and their cross-reactivity to pollen. Eur. Food Res. Technol., 212, 212.[CrossRef][ISI]
Petersen, A., Vieths, S., Aulepp, H., Schlaak, M., and Becker, W.M. (1996) Ubiquitous structures responsible for IgE cross-reactivity between tomato fruit and grass pollen allergens. J. Allergy Clin. Immunol., 98, 805815.[ISI][Medline]
Spik, G., Debruyne, V., Montreuil, J., van Halbeek, H., and Vliegenthart, J.F. (1985) Primary structure of two sialylated triantennary glycans from human serotransferrin. FEBS Lett., 183, 6569.[CrossRef][ISI][Medline]
Tretter, V., Altmann, F., Kubelka, V., März, L., and Becker, W.M. (1993) Fucose linked 1-3 to the core-region of glycoprotein N-glycans creates an important epitope for IgE from honeybee venom allergic individuals. Int. Arch. Allergy Immunol., 102, 259266.[ISI][Medline]
van der Veen, M.J., van Ree, R., Aalberse, R.C., Akkerdaas, J., Koppelman, S.J., Jansen, H.M., and van der Zee, J.S. (1997) Poor biologic activity of cross-reactive IgE directed to carbohydrate determinants of glycoproteins. J. Allergy Clin. Immunol., 100, 327334.[ISI][Medline]
van Die, I., Gomord, V., Kooyman, F.N.J., van den Berg, T.K., Cummings, R.D., and Vervelde, L. (1999) Core 1
3-fucose is a common modification of N-glycans in parasitic helminths and constitutes an important epitope for IgE from Haemonchus contortus infected sheep. FEBS Lett., 463, 189193.[CrossRef][ISI][Medline]
van Kuik, J.A., van Halbeek, H., Kamerling, J.P., and Vliegenthart, J.F. (1985) Primary structure of the low-molecular-weight carbohydrate chains of Helix pomatia -hemocyanin. Xylose as a constituent of N-linked oligosaccharides in an animal glycoprotein. J. Biol. Chem., 260, 1398413988.
van Ree, R. (2002) Carbohydrate epitopes and their relevance for the diagnosis and treatment of allergic diseases. Int. Arch. Allergy Immunol., 129, 189197.[CrossRef][ISI][Medline]
van Ree, R., Cabanes-Macheteau, M., Akkerdaas, J., Milazzo, J.P., Loutelier-Bourhis, C., Rayon, C., Villalba, M., Koppelman, S., Aalberse, R., Rodriguez, R., and others. (2000) ß(1,2)-Xylose and (1,3)-fucose residues have a strong contribution in IgE binding to plant glycoallergens. J. Biol. Chem., 275, 1145111458.
Welply, J.K., Abbas, S.Z., Scudder, P., Keene, J.L., Broschat, K., Casnocha, S., Gorka, C., Steininger, C., Howard, S.C., and Schmuke, J.J. (1994) Multivalent sialyl-LeX: potent inhibitors of E-selectin-mediated cell adhesion; reagent for staining activated endothelial cells. Glycobiology, 4, 259265.[Abstract]
Westphal, S., Kolarich, D., Foetisch, K., Lauer, I., Altmann, F., Conti, A., Crespo, J.F., Miranda, E.E., Vieths, S., and Scheurer, S. (2003) Molecular characterization and allergenic activity of Lyc e 2 (ß-fructofuranosidase), a glycosylated allergen of tomato. Eur. J. Biochem., 270, 13271337.
Wilson, I.B.H. (2002) Glycosylation of proteins in plants and invertebrates. Curr. Opin. Struct. Biol., 12, 569577.[CrossRef][ISI][Medline]
Wilson, I.B.H. and Altmann, F. (1998) Structural analysis of N-glycans from allergenic grass, ragweed and tree pollens. Core 1,3-fucose and xylose present in all pollens examined. Glycoconj. J., 15, 10551070.[CrossRef][ISI][Medline]
Wilson, I.B.H., Harthill, J.E., Mullin, N., Ashford, D., and Altmann, F. (1998) Core 1,3-fucose is a key part of the epitope recognized by antibodies reacting against plant N-linked oligosaccharides. Glycobiology, 8, 651661.
Wilson, I.B.H., Zeleny, R., Kolarich, D., Staudacher, E., Stroop, C.J.M., Kamerling, J.P., and Altmann, F. (2001) Analysis of Asn-linked glycans from vegetable foodstuffs: widespread occurrence of Lewis a, core 1,3-linked fucose and xylose substitutions. Glycobiology, 11, 261274.
Yi, D., Lee, R.T., Longo, P., Boger, E.T., Lee, Y.C., Petri, W.A. Jr., and Schnaar, R.L. (1998) Substructural specificity and polyvalent carbohydrate recognition by the Entamoeba histolytica and rat hepatic N-acetylgalactosamine/galactose lectins. Glycobiology, 8, 10371043.
Zeleny, R., Altmann, F., and Praznik, W. (1997) A capillary electrophoretic study on the specificity of ß-galactosidases from Aspergillus oryzae, Escherichia coli, Streptococcus pneumoniae and Canavalia ensiformis (jack bean). Anal. Biochem., 246, 96101.[CrossRef][ISI][Medline]