van Hage-Hamsten M, Johansson E, Roquet A, Peterson C, Andersson M, Greiff L, Vrtala S, Valenta R, Grönneberg R
Department of Medicine, Division of Clinical Immunology, Karolinska Institute and Hospital, Stockholm, Sweden.
Clin Exp Allergy. 2002 Oct;32(10):1448-53. doi: 10.1046/j.1365-2745.2002.01495.x.
Genetic engineering of the major birch pollen allergen (Bet v 1) has led to the generation of recombinant Bet v 1 derivatives with markedly reduced IgE-binding capacity, but with retained T cell activating ability.
To compare the mucosal reactivity to rBet v 1 derivatives with rBet v 1 wild-type as basis for new therapeutic strategies for birch pollen allergy based on mucosal tolerance induction.
Outside the pollen season, 10 patients with birch pollen allergic rhinitis and mild asthma underwent four nasal challenge-sessions in a randomized, double-blind, and cross-over design, employing increasing doses of rBet v 1 fragment mix, rBet v 1 trimer, rBet v 1 wild-type and diluent (albumin). Nasal lavage fluids (NAL) were collected before the challenge-series as well as 10 min, 4 and 24 h thereafter. Nasal lavage fluid levels of tryptase as well as EPO and ECP were measured as indices of mast cell and eosinophil activity, respectively.
All 10 patients tolerated the highest accumulated dose, 8.124 microg, when challenged with rBet v 1 trimer, eight with rBet v 1 fragments compared to one when challenged with rBet v 1 wild-type. No late phase reactions were observed. The change in tryptase levels (pre-challenge vs. 10 min) was significantly lower after challenges with rBet v 1 trimer and rBet v 1 fragments than with rBet v 1 wild-type. The change in EPO/ECP concentration pre-challenge versus 4 h post-challenge was lower for rBet v 1 trimer and the change was significantly lower when pre-challenge versus 24 h post-challenge to rBet v 1 fragments and rBet v 1 wild-type was examined.
The derivatives induced significantly fewer symptoms and lower mast cell and eosinophil activation than rBet v 1 wild-type upon application to the nasal mucosa. They could in the future be candidates for immunotherapy based on mucosal tolerance induction.
对主要桦树花粉过敏原（Bet v 1）进行基因工程改造已产生重组Bet v 1衍生物，其IgE结合能力显著降低，但保留了T细胞激活能力。
以rBet v 1野生型为基础，比较对rBet v 1衍生物的黏膜反应性，为基于黏膜耐受诱导的桦树花粉过敏新治疗策略提供依据。
在花粉季节之外，10例桦树花粉过敏性鼻炎和轻度哮喘患者采用随机、双盲、交叉设计进行了4次鼻腔激发试验，使用递增剂量的rBet v 1片段混合物、rBet v 1三聚体、rBet v 1野生型和稀释剂（白蛋白）。在激发试验系列之前以及之后10分钟、4小时和24小时收集鼻腔灌洗液（NAL）。分别测量鼻腔灌洗液中类胰蛋白酶以及EPO和ECP的水平，作为肥大细胞和嗜酸性粒细胞活性的指标。
用rBet v 1三聚体激发时，所有10例患者均耐受最高累积剂量8.124微克；用rBet v 1片段激发时，8例患者耐受，而用rBet v 1野生型激发时只有1例患者耐受。未观察到迟发相反应。用rBet v 1三聚体和rBet v 1片段激发后，类胰蛋白酶水平的变化（激发前与10分钟时相比）显著低于用rBet v 1野生型激发。rBet v 1三聚体激发前与激发后4小时的EPO/ECP浓度变化较低，当检查激发前与激发后24小时的rBet v 1片段和rBet v 1野生型时，变化显著更低。
与rBet v 1野生型相比，这些衍生物应用于鼻黏膜时诱发的症状明显更少，肥大细胞和嗜酸性粒细胞激活更低。它们未来可能成为基于黏膜耐受诱导的免疫治疗候选药物。
