Mutational epitope analysis of Pru av 1 and Api g 1, the major allergens of cherry (Prunus avium) and celery (Apium graveolens):: correlating IgE reactivity with three-dimensional structure
Mutational epitope analysis of Pru av 1 and Api g 1, the major allergens of cherry (Prunus avium) and celery (Apium graveolens):: correlating IgE reactivity with three-dimensional structure
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DOI：
10.1042/bj20031057
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发表时间：
2003-11-15
影响因子：
4.1
通讯作者：
Scheurer, S
中科院分区：
文献类型：
--
作者：
Neudecker, P;Lehmann, K;Scheurer, S
桦树花粉症经常伴随着对食物的不良反应，这是由于花粉过敏原特异性IgE与同源食物过敏原交叉反应所致。例如，主要的樱桃(Prunus Avium)变应原Pru av 1的三级结构与主要的桦树(Betula Verrucosa)花粉变应原Bet v 1几乎相同。为了确定交叉反应的Ig E表位，我们用免疫印迹、EAST(酶过敏吸附试验)、CD和核磁共振谱分析了芹菜(ApiumGraveolens)主要变应原Pru av 1和Api g 1.0101的突变体。在樱桃过敏患者中，已知的Bet v1的IgE表位P-loop区的Glu(45)突变为Trp(45)，显著减少了IgE与Pru av I的结合。Pru-av-1野生型的骨架构象在Pru-av-1Trp(45)的三维结构中是保守的，表明Glu(45)的侧链参与了交叉反应的IgE表位。因此，对于芹菜过敏患者的一个亚组，Lys(44)到Glu的突变增强了与同源芹菜过敏原Api g 1.0101的IgE结合。PrU av 1 Pro(112)突变体对IgE的反应性几乎完全丧失是由于其三级结构的破坏。Ala(112)突变和C-末端155-159残基的缺失都不影响IgE与Pru av 1的结合。总之，P-环的结构部分解释了交叉反应模式，通过定点突变调节IgE结合是开发针对患者定制的特异性免疫治疗的低过敏变异体的一种有前途的方法。
Birch pollinosis is often accompanied by adverse reactions to food due to pollen-allergen specific IgE cross-reacting with homologous food allergens. The tertiary structure of Pru av 1, the major cherry (Prunus avium) allergen, for example, is nearly identical with Bet v 1, the major birch (Betula verrucosa) pollen allergen. In order to define cross-reactive IgE epitopes, we generated and analysed mutants of Pru av 1 and Api g 1.0101, the major celery (Apium graveolens) allergen, by immunoblotting, EAST (enzyme allergosorbent test), CD and NMR spectroscopy. The mutation of Glu(45) to Trp(45) in the P-loop region, a known IgE epitope of Bet v 1, significantly reduced IgE binding to Pru av I in a subgroup of cherry-allergic patients. The backbone conformation of Pru av 1 wild-type is conserved in the three-dimensional structure of Pru av 1 Trp(45), demonstrating that the side chain of Glu(45) is involved in a cross-reactive IgE epitope. Accordingly, for a subgroup of celery-allergic patients, IgE binding to the homologous celery allergen Api g 1.0101 was enhanced by the mutation of Lys(44) to Glu. The almost complete loss of IgE reactivity to the Pru av 1 Pro(112) mutant is due to disruption of its tertiary structure. Neither the mutation Ala(112) nor deletion of the C-terminal residues 155-159 influenced IgE binding to Pru av 1. In conclusion, the structure of the P-loop partially explains the cross-reactivity pattern, and modulation of IgE-binding by site-directed mutagenesis is a promising approach to develop hypo-allergenic variants for patient-tailored specific immunotherapy.