Asensio Teresa, Crespo Jesus F, Sanchez-Monge Rosa, Lopez-Torrejon Gema, Somoza Maria L, Rodriguez Julia, Salcedo Gabriel
Departamento de Biotecnología, Escuela Técnica Superior Ingenieros Agrónomos, Universidad Polytécnica de Madrid, Spain.
J Allergy Clin Immunol. 2004 Oct;114(4):896-9. doi: 10.1016/j.jaci.2004.06.014.
Members belonging to 9 different families of plant pathogenesis-related (PR) proteins have been identified as pollen and food allergens. However, no PR-1 protein, a family widely distributed throughout the plant kingdom, has been involved so far in allergic reactions. On the other hand, melon ranges among the most relevant fruits causing food allergy in some countries, but the majority of its allergens remain still unidentified.
We sought to identify melon allergens related to plant PR proteins.
A serum pool or individual sera from 17 patients with allergy to melon confirmed by means of double-blind, placebo-controlled food challenge were used to detect IgE binding proteins of extracts from melon pulp and juice. Cuc m 3 was isolated from melon juice by reverse-phase HPLC and characterized by means of N-terminal amino acid sequencing of internal peptides, matrix-assisted laser desorption/ionization mass spectrometry analysis, direct and inhibition ELISA assays, and skin prick tests.
Cuc m 3 was a minor component of the melon juice, with a molecular weight of 16,097 d and a blocked N-terminus. N-terminal amino acid sequences of 3 different peptides derived from endo-Lys C digestion (overall 41 residues) showed more than 60% of sequence identity with PR-1 proteins from grape and cucumber. Cuc m 3 bound IgE from 12 of 17 sera from patients allergic to melon and inhibited approximately 40% and 70% of the IgE binding to melon pulp and juice extracts, respectively. Positive skin prick test responses to purified Cuc m 3 were found in 2 of 14 allergic patients.
A new melon allergen belonging to the PR-1 protein family has been isolated and characterized. It is the first evidence of the involvement of this plant protein family in food allergy.
已鉴定出属于9个不同植物病程相关（PR）蛋白家族的成员为花粉和食物过敏原。然而，迄今尚未发现广泛分布于植物界的PR - 1蛋白家族成员参与过敏反应。另一方面，甜瓜是一些国家引起食物过敏的最主要水果之一，但其大多数过敏原仍未明确。
我们试图鉴定与植物PR蛋白相关的甜瓜过敏原。
采用经双盲、安慰剂对照食物激发试验确诊的17例甜瓜过敏患者的混合血清或个体血清，检测甜瓜果肉和果汁提取物中的IgE结合蛋白。通过反相高效液相色谱从甜瓜汁中分离出Cuc m 3，并通过内部肽段的N端氨基酸测序、基质辅助激光解吸/电离质谱分析、直接和抑制ELISA试验以及皮肤点刺试验进行鉴定。
Cuc m 3是甜瓜汁中的一种次要成分，分子量为16,097 d，N端封闭。来自内肽酶Lys C消化产生的3种不同肽段的N端氨基酸序列（共41个残基）与葡萄和黄瓜的PR - 1蛋白显示出超过60%的序列同一性。Cuc m 3与17例甜瓜过敏患者血清中的12例IgE结合，并分别抑制约40%和70%的IgE与甜瓜果肉和果汁提取物的结合。在14例过敏患者中的2例对纯化的Cuc m 3皮肤点刺试验呈阳性反应。
已分离并鉴定出一种属于PR - 1蛋白家族的新型甜瓜过敏原。这是该植物蛋白家族参与食物过敏的首个证据。
