花生过敏原Ara h1免疫显性抗原决定簇的鉴别

Identification of the Immunodominant Epitopes on Ara h1,a Major Peanut Allergen

为探索花生过敏原致敏机理,采用固相合成肽技术合成Ara h1的23条多肽。以花生过敏患者血清为抗体,鉴别和定位Ara h1的抗原决定簇。结果表明:Ara h1第21～34位,第89～98位,第393～403位,第498～507位,第594～605位氨基酸序列识别率在60%以上,为Arah1的抗原决定簇,其中第498～507位的多肽识别率为100%,是显性抗原决定簇,其氨基酸序列为RRYTARLKEG。用丙氨酸依次取代显性抗原决定簇的每个氨基酸,结果抗原决定簇的致敏性增强或丧失,说明Ara h1第499位和第503位的精氨酸和第502位的丙氨酸为降低Ara h1致敏性的关键氨基酸。

In order to explore the sensibilization mechanism of peanut allergen, Ara hi. 23 peptides were synthesized using solid-phase synthesis on the basis of the sequence of Ara hl. Serum IgE from patients with documented peanut hypersensitivity reactions was used to screen the linear IgE-binding epitopes on Ara h 1. Results showed that the peptides at AA 21-34, 89-98, 393-403, 498-507, and 594-605 were considered as epitopes since they were reeognized by IgE from at least 60% of the sera tested, moreover, 100% IgE from patients interacted with the immunodominant epitope at AA 498-507 （RRYTARLKEG）. Mutational analysis of the immunodominant epitope showed that single amino acid changes had dramatic effects on IgE-binding characteristics. In comparison with the native peptide, single site substituted peptides R499, A502, R503 resulted in total loss of IgE binding. The key amino acids which can reduce the sensibility of Ara h 1 are arginine and alanine.