van Hoffen E, van der Kleij H P M, den Hartog Jager C F, van Doorn W A, Knol E F, Opstelten D-J, Koppelman S J, Knulst A C
Department of Dermatology/Allergology, University Medical Center Utrecht, Utrecht, The Netherlands.
Clin Exp Allergy. 2014 Dec;44(12):1558-66. doi: 10.1111/cea.12319.
Specific immunotherapy for peanut allergy is associated with significant side-effects. Chemically modified allergens may provide a safer alternative.
This study aimed to analyse the immunogenicity and allergenicity of modified peanut conglutin.
Native peanut conglutin and two modifications thereof were generated (RA and RAGA). Conglutin-specific T cell lines from 11 peanut-allergic patients were analysed for proliferation and cytokine production. Sera from 14 patients were analysed for IgE/IgG1/IgG4 binding by immunoblot and ELISA. IgE reactivity was analysed by direct and indirect basophil activation test (BAT), in presence and absence of patient plasma or CD32-blocking antibodies.
T cell proliferation to RA was unchanged, and proliferation to RAGA was reduced compared to native conglutin. Cytokine profiles remained unchanged. IgE, IgG1 and IgG4 binding to RA and RAGA was significantly reduced. In the direct BAT, the relative potency of modified conglutin was decreased in 67% and increased/similar in 33% of the patients. In the indirect BAT, RA and RAGA were 10-100 times less potent than native conglutin. Addition of plasma to the indirect BAT increased the relative potency of modified conglutin in patients with high peanut-specific IgG levels. This was mediated via blocking of the response to native conglutin, most likely by soluble IgG, and not via CD32.
Chemical modification of peanut conglutin by RA retains immunogenicity and reduces allergenicity and may be a promising approach for development of a curative treatment for peanut allergy. In a subgroup of patients, where the reactivity of native conglutin is already partially blocked by IgG, the effect of the modification of conglutin is less pronounced.
花生过敏的特异性免疫疗法伴有显著的副作用。化学修饰的变应原可能提供一种更安全的选择。
本研究旨在分析修饰后的花生凝集素的免疫原性和变应原性。
制备天然花生凝集素及其两种修饰产物（RA和RAGA）。分析来自11名花生过敏患者的凝集素特异性T细胞系的增殖和细胞因子产生情况。通过免疫印迹和酶联免疫吸附测定法分析14名患者血清中的IgE/IgG1/IgG4结合情况。在有或无患者血浆或CD32阻断抗体的情况下，通过直接和间接嗜碱性粒细胞激活试验（BAT）分析IgE反应性。
与天然凝集素相比，T细胞对RA的增殖未改变，对RAGA的增殖降低。细胞因子谱保持不变。IgE、IgG1和IgG4与RA和RAGA的结合显著减少。在直接BAT中，67%的患者修饰凝集素的相对效力降低，33%的患者增加/相似。在间接BAT中，RA和RAGA的效力比天然凝集素低10 - 100倍。在间接BAT中加入血浆可增加花生特异性IgG水平高的患者中修饰凝集素的相对效力。这是通过阻断对天然凝集素的反应介导的，最可能是通过可溶性IgG，而不是通过CD32。
用RA对花生凝集素进行化学修饰可保留免疫原性并降低变应原性，可能是开发花生过敏治愈性疗法的一种有前景的方法。在一部分患者中，天然凝集素的反应性已被IgG部分阻断，凝集素修饰的效果不太明显。
