Calabozo B, Barber D, Polo F
Research and Development Department, ALK-Abelló, Madrid, Spain.
Clin Exp Allergy. 2002 Nov;32(11):1628-34. doi: 10.1046/j.1365-2222.2002.01530.x.
Pla l 1, the major allergen of Plantago lanceolata pollen, is a glycoprotein that contains an N-glycosylation site. Carbohydrate moieties of many allergenic glycoproteins have been reported to be IgE-binding determinants responsible for cross-reactivity among different species.
To identify the kind of linkages and the type of glycans present in Pla l 1 and to investigate their contribution to the allergic response to this allergen.
Pla l 1 was deglycosylated by N-glycosidase A and the IgE-binding ability of the unglycosylated protein was evaluated by dot-blot. Identification of beta1 --> 2 xylose and/or alpha1 --> 3 fucose residues in Pla l 1 N-glycan was carried out by incubation with specific antibodies from rabbit antiserum against HRP (anti-HRP). The contribution of this N-glycan to total IgE reactivity was analysed quantitatively by pre-incubation of Pla l 1 with anti-HRP prior to incubation with sera. The role of the carbohydrate moiety of Pla l 1 in cross-reactivity was studied by RAST using unrelated glycoproteins with known sugar composition and structure.
The effectiveness of N-glycosidase A to deglycosylate Pla l 1 and the ineffectiveness of the treatment with PNGase F indicate that Pla l 1 carries a complex N-glycan with an alpha1 --> 3 fucose residue in its structure. Furthermore, the presence of beta1 --> 2 xylose and/or alpha1 --> 3 fucose residues was identified in this N-glycan by means of an ELISA. Pre-incubation of Pla l 1 with an anti-HRP antibody caused a weak but significant reduction in IgE reactivity. Some sera from P. lanceolata-allergic patients reacted positively with four glycoproteins that bear N-glycans of complex type but not with fetuine.
Pla l 1 is a glycoprotein that carries at least a complex, major N-linked glycan, with a alpha1 --> 3 fucose residue in its structure and probably also a beta1 --> 2 xylose. This glycan moiety does not seem to constitute a relevant allergenic epitope of Pla l 1.
窄叶车前花粉的主要变应原Pla l 1是一种含有N - 糖基化位点的糖蛋白。据报道，许多变应原性糖蛋白的碳水化合物部分是负责不同物种间交叉反应的IgE结合决定簇。
确定Pla l 1中存在的连接类型和聚糖类型，并研究它们对该变应原过敏反应的作用。
用N - 糖苷酶A对Pla l 1进行去糖基化处理，并通过斑点印迹法评估去糖基化蛋白的IgE结合能力。通过与兔抗HRP抗血清中的特异性抗体孵育，鉴定Pla l 1 N - 聚糖中的β1→2木糖和/或α1→3岩藻糖残基。在与血清孵育之前，通过将Pla l 1与抗HRP预孵育，定量分析这种N - 聚糖对总IgE反应性的贡献。使用具有已知糖组成和结构的不相关糖蛋白，通过RAST研究Pla l 1碳水化合物部分在交叉反应中的作用。
N - 糖苷酶A对Pla l 1去糖基化的有效性以及PNGase F处理的无效性表明，Pla l 1在其结构中携带一种具有α1→3岩藻糖残基的复杂N - 聚糖。此外，通过ELISA在该N - 聚糖中鉴定出β1→2木糖和/或α1→3岩藻糖残基的存在。用抗HRP抗体对Pla l 1进行预孵育导致IgE反应性有微弱但显著的降低。一些对窄叶车前过敏患者的血清与四种带有复杂型N - 聚糖的糖蛋白呈阳性反应，但与胎球蛋白无反应。
Pla l 1是一种糖蛋白，其结构中至少携带一种复杂的主要N - 连接聚糖，带有α1→3岩藻糖残基，可能还带有β1→2木糖。这种聚糖部分似乎不构成Pla l 1的相关变应原表位。
