昆虫叮咬所引起的过敏是过敏反应中的重要类型。在昆虫叮咬过程中，它们直接将毒腺、唾液腺中有毒或能导致过敏的物质成份直接注入人体内，它相对于经皮肤接触、呼吸道吸入过敏原有时更为严重，可引起过敏性休克。
牛虻的2种过敏原蛋白被发现
目前人们对蚊子、蜜蜂、胡蜂导致过敏的研究报告较多，但对牛虻导致人体过敏的物质成份鲜有了解。前期，中国科学院昆明动物研究所赖仞研究员领导的团队首次从姚虻唾液腺中分离纯化鉴定了两个天然的过敏原蛋白分子Tab a1和Tab a2，研究成果发表于Allergen(2010,Jul 2)。近期，该团队又从牛虻唾液腺中纯化到一种新的过敏原Tab y1，它是一种Apyrase,并具有较强的抑制血小板聚集活性。通过皮肤针刺实验（SPT）发现对牛虻过敏的病人中有约70%对Tab y1呈阳性。通过Western blot检测发现Tab y1对采集的37份牛虻过敏病人血清IgE阳性率为81%，通过Elisa competitive inhibition发现，它可以剂量依赖的方式竞争性抑制病人血清IgE与牛虻唾液腺总蛋白的结合，因此它是牛虻唾液腺中的一种major allergen。
这些成果加深了对牛虻所引起过敏反应的了解，对昆虫刺蛰过敏反应的诊断和治疗具有重要意义。
该成果发表于过敏反应领域的著名期刊《过敏原》。
相关英文论文摘要：
A novel allergen Tab y 1 with inhibitory activity of platelet aggregation
from salivary glands of horseflies
Background: Horsefly sting causes allergic reactions in human body. However, our knowledge on horsefly allergens remains poor.
Objectives: To identify the novel horsefly allergens and characterize their properties.
Methods: A native allergen protein Tab y 1 (apyrase) was purified from the salivary glands of the horsefly Tabanus yao Macquart by gel filtration and ion exchange chromatography. Its sequence was determined by Edman degradation and cDNA cloning. Its allergenicity was assessed by immunoblotting for specific IgE, basophil activation test, skin prick test (SPT), and competitive enzyme-linked immunosorbent assay (ELISA).
Results: Tab y 1 showed a single diffusion band of 70 kDa on SDS-PAGE. Seventy percent (7/10) of patients with horsefly allergy tested positive to Tab y 1 in SPT; sera from 81% (30/37) of patients reacted to Tab y 1 on western blots. Purified Tab y 1 reduced approximately 42% sera IgE reactivity to horsefly salivary gland extract on a competitive ELISA. Tab y 1 upregulated the expression of CD63 and CCR3 on passively sensitized basophils by up to approximately 4.9-fold. Tab y 1 also showed enzymatic activity to hydrolyze ATP and ADP, and potent antiplatelet aggregation and antithrombotic activities.
Conclusion: The current work identified a novel major allergen of horsefly, Tab y 1, with antiplatelet aggregation and antithrombotic activities, which implicates Tab y 1 in helping horseflies suck host blood, meanwhile causing allergy in their human hosts.
英文论文链接：https://onlinelibrary.wiley.com/doi/10.1111/j.1398-9995.2011.02683.x/abstract
