The Graduate School.
Natural Sciences Unit, College of Science.
Asian Pac J Allergy Immunol. 2017 Dec;35(4):203-211. doi: 10.12932/AP0794.
Blo t 5, a major allergen from the house dust mite Blomia tropicalis had been identified as an important trigger of allergic diseases. Effects of sequence variations to the IgE binding activity of Blo t 5 remain unclear.
The study determined gene polymorphisms of Blo t 5, expressed the recombinant Blo t 5 allergen in E. coli system and determined its IgE reactivity in house dust mite allergic Filipino patients.
Gene polymorphism was determined using Polymerase Chain Reaction and DNA sequencing. Recombinant Blo t 5 was expressed as a GST-fusion protein in E. coli and purified by affinity chromatography. IgE-binding activity of 230 age-and sex-matched allergic and non-allergic subjects was subjected to Enzyme-linked Immunosorbent Assay and Western blot analysis.
Five polymorphic variants of Blo t 5 were identified with 26 DNA base and 12 amino acid substitutions thus implying a high degree of sequence diversity. Of the 115 cases, 68.70% and 59.13% showed reactivity to Blo t extract and rBlo t 5 respectively. Total and specific IgE levels of allergic and non-allergic subjects differ significantly (p< 0.0001).
Blo t 5 gene exhibits polymorphic variants with predicted amino acid sequences resulting to changes in its IgE epitopes. These polymorphisms may suggest variability of allergenic properties of Blo t 5. The incorporation of the Blo t 5 variants in the panel of diagnostic allergens and immunotherapy is highly recommended.
布罗美索 5 是一种来自热带家尘螨的主要过敏原，已被确定为过敏疾病的重要触发因素。序列变异对布罗美索 5 的 IgE 结合活性的影响尚不清楚。
本研究确定了布罗美索 5 的基因多态性，在大肠杆菌系统中表达重组布罗美索 5 过敏原，并测定其在菲律宾尘螨过敏患者中的 IgE 反应性。
采用聚合酶链反应和 DNA 测序法确定基因多态性。将重组布罗美索 5 作为 GST 融合蛋白在大肠杆菌中表达，并通过亲和层析进行纯化。对 230 名年龄和性别匹配的过敏和非过敏受试者的 IgE 结合活性进行酶联免疫吸附试验和 Western blot 分析。
鉴定出布罗美索 5 的 5 种多态变体，其 DNA 碱基和 12 个氨基酸发生了 26 个替换，表明其序列多样性很高。在 115 例病例中，68.70%和 59.13%分别对布罗美索提取物和 rBlo t 5 有反应性。过敏和非过敏受试者的总 IgE 和特异性 IgE 水平差异有统计学意义（p<0.0001）。
布罗美索 5 基因表现出多态性变体，其预测的氨基酸序列导致其 IgE 表位发生变化。这些多态性可能提示布罗美索 5 的变应原特性存在差异。强烈建议将布罗美索 5 变体纳入诊断过敏原和免疫治疗的面板中。
