Gao Yun Feng, Wang De Yun, Ong Tan Ching, Tay Su Ling, Yap Kwong Hsia, Chew Fook Tim
Department of Biological Sciences, National University of Singapore, Singapore.
J Allergy Clin Immunol. 2007 Jul;120(1):105-12. doi: 10.1016/j.jaci.2007.02.032. Epub 2007 Apr 18.
Allergenic components from Blomia tropicalis are important triggers of allergies in the tropics.
We sought to identify and characterize a novel allergen, Blo t 21, from B tropicalis.
Blo t 21 was initially identified from an expressed sequence tag database generated from a B tropicalis cDNA library. Allergenicity of this antigen was examined by means of skin prick testing, ELISA, and IgE immuno-dot blotting. We evaluated whether Blo t 21 and Blo t 5 were cross-reactive by using IgE inhibition ELISAs.
Blo t 21, a 129-amino-acid protein sharing 39% identity with Blo t 5, is a product of a single-copy gene. It has an alpha-helical secondary structure and localizes to midgut and hindgut contents of B tropicalis, as well as fecal particles. Positive responses to Blo t 21 were shown in 93% (40/43) by means of ELISA and 95% (41/43) by means of skin prick testing when assayed in 43 adult patients with ongoing persistent allergic rhinitis. However, sera of 494 consecutive individuals attending outpatient allergy clinics over 1(1/2) years showed 57.9% (286/494) had positive responses to Blo t 21. Although the majority (>75%) of sensitized individuals were cosensitized to both Blo t 5 and Blo t 21, these 2 allergens had a low-to-moderate degree of cross-reactivity.
Blo t 21 is a major allergen in B tropicalis that is not highly cross-reactive to Blo t 5, despite sharing some sequence and structural identity.
Blo t 21, representing a new group of allergens, is an important B tropicalis allergen.
热带无爪螨的变应原成分是热带地区过敏反应的重要触发因素。
我们试图从热带无爪螨中鉴定并表征一种新型变应原Blo t 21。
Blo t 21最初是从热带无爪螨cDNA文库生成的表达序列标签数据库中鉴定出来的。通过皮肤点刺试验、酶联免疫吸附测定（ELISA）和IgE免疫斑点印迹法检测该抗原的变应原性。我们使用IgE抑制ELISA评估Blo t 21和Blo t 5是否存在交叉反应。
Blo t 21是一种由129个氨基酸组成的蛋白质，与Blo t 5有39%的同源性，是单拷贝基因的产物。它具有α螺旋二级结构，定位于热带无爪螨的中肠和后肠内容物以及粪便颗粒中。在43例持续性变应性鼻炎成年患者中进行检测时，ELISA显示93%（40/43）的患者对Blo t 21呈阳性反应，皮肤点刺试验显示95%（41/43）的患者呈阳性反应。然而，在1年半的时间里，连续494名到门诊过敏诊所就诊的个体血清显示，57.9%（286/494）的个体对Blo t 21呈阳性反应。尽管大多数（>75%）致敏个体对Blo t 5和Blo t 21均呈共致敏状态，但这两种变应原的交叉反应程度较低。
Blo t 21是热带无爪螨中的一种主要变应原，尽管与Blo t 5有一些序列和结构上的同源性，但与Blo t 5的交叉反应性不高。
Blo t 21代表了一组新的变应原，是热带无爪螨的一种重要变应原。
