目的对屋尘螨主要变应原(Derp1)蛋白分子中与过敏病人血清特异性IgE相结合的表位序列的鉴定。进而获得基于串联表位的小分子低毒过敏原以作为新的免疫治疗剂。方法采用全蛋白序列重叠扫描法对Derp1蛋白进行全表位筛选,即合成了覆盖Derp1全蛋白222个氨基酸的31段各含15个氨基酸的多肽,且相邻肽段间有8个氨基酸的重叠。并将这些肽段按点状固相多肽合成法依顺序合成于纤维膜上。再将该膜与由数份过敏血清组成的血清池孵育,经抗人IgE-HRP二抗结合及X光片显影后对阳性点进行灰度比对及分析。结果经对X光片阳性点的比对及分析,我们确定出了Derp1过敏原蛋白中的3个强阳性表位序列。它们是位于第85~99位的氨基酸序列(表位1,Ep1),第106~120位的氨基酸序列(表位2,Ep2)及第190~204位的氨基酸序列(表位3,Ep3)。结论我们获得了Derp1中3个15肽的线性IgE结合表位(B细胞表位)序列。证实了Derp1分子中存在IgE结合的线性表位。为进一步构建T/B细胞串联表位的小分子低毒过敏原提供了物质基础。
Objective To identify the IgE-binding epitopes in the allergen Der p 1 of main house dust mites,which can be recognized by the specific IgE in the sera from allergic individuals,and obtain a hypoallergen derived from the T-B epitope fused peptide for potential use in specific immunotherapy(SIT).Methods Thirty-one peptides containing 15 amino acids each,which covered the full 222 amino acids of Der p 1 protein sequence,were synthesized on the cellulous membrane by solid-phase peptide(SPOTs) synthesis,with 8 overlapping amino acids between every two neighboring peptides.The membrane bearing the spots of the synthesized peptides were incubated with the allergic serum pools consisting of the sera from 5 allergic individuals.The membrane was then probed with HRP-conjugated anti-human IgE,followed by enhanced chemiluminescence(ECL) for visualization and gray scale analysis of the positive peptide spots.Results Three strong IgE-binding epitopes were identified in the amino acid sequence of Der p 1 molecule,namely Ep1(amino acids 85-99),Ep2(amino acids 106-120) and Ep3(amino acids 190-204).Conclusion The 3 IgE-binding epitopes(B cell epitopes) identified in Der p 1 confirm the presence of linear epitopes in Der p 1,suggesting the possibility of constructing T/B epitope-fused hypoallergens.