Institute of Protein Biochemistry, CNR, Naples, Italy; Center for Molecular Allergology, IDI-IRCCS, Rome, Italy.
Clin Exp Allergy. 2013 Jan;43(1):128-40. doi: 10.1111/cea.12028.
Among the peach-derived allergens which are already known, the lipid transfer protein (Pru p 3) seems to be the one to exert severe allergic reactions.
To identify and characterize a new peach allergen causing a clinical picture similar to that of Pru p 3.
Patients were selected on the basis of their severe clinical reactivity and negative results to a panel of peach allergens available on the ISAC103 microarray. Several in-house and commercial preparations were compared. Several methods were used to characterize the newly identified molecule. Specific IgE and inhibition assays were performed using the Allergen micro-Beads Array (ABA) assay.
Negative ISAC results to Pru p 3 were confirmed by additional testing in contrast with the positive results obtained by commercial Pru p 3-enriched peach peel extracts. The analyses of one of these preparations led to the identification of Peamaclein, a new allergenic protein. It is a small, basic, cysteine-rich, heat-stable, digestion-resistant protein, homologous to a potato antimicrobial peptide. Peamaclein was able to trigger positive skin test reactions and to bind IgE in the ABA assay. It displays an electrophoretic mobility and chromatographic behaviour similar to that of Pru p 3; therefore, it can be hidden in Pru p 3 preparations. In fact, Pru p 3-enriched peach peel extracts were found to contain both Pru p 3 and Peamaclein by means of comparative in vivo testing, and by biochemical and immunochemical assays. Commercially available anti-Pru p 3 polyclonal antibodies were found to have a double specificity for the two molecules.
A new allergen from peach belonging to a new family of allergenic proteins has been identified and characterized. This knowledge on Peamaclein will improve our understanding on the clinical aspects of the peach allergy and the quality of diagnostic reagents.
在已知的桃过敏原中，脂质转移蛋白（Pru p 3）似乎是引起严重过敏反应的过敏原。
鉴定和表征一种新的桃过敏原，其引起的临床症状与 Pru p 3 相似。
根据严重的临床反应性和 ISAC103 微阵列上可用的桃过敏原组合的阴性结果选择患者。比较了几种内部和商业制剂。使用几种方法来表征新鉴定的分子。使用过敏原微珠阵列（ABA）测定法进行特异性 IgE 和抑制测定。
与从商业桃皮提取物中获得的阳性结果相反，Pru p 3 的 ISAC 结果为阴性，经进一步检测得到证实。对其中一种制剂的分析导致鉴定出一种新的致敏蛋白，即 Peamaclein。它是一种小的、碱性的、富含半胱氨酸的、热稳定的、消化抗性蛋白，与一种马铃薯抗菌肽同源。Peamaclein 能够引发阳性皮肤测试反应，并在 ABA 测定中结合 IgE。它显示出与 Pru p 3 相似的电泳迁移率和色谱行为；因此，它可以隐藏在 Pru p 3 制剂中。事实上，通过比较体内测试、生化和免疫化学测定，发现富含 Pru p 3 的桃皮提取物中含有 Pru p 3 和 Peamaclein。商业上可用的抗 Pru p 3 多克隆抗体被发现对这两种分子具有双重特异性。
从桃中鉴定和表征了一种属于新过敏原家族的新过敏原。对 Peamaclein 的了解将提高我们对桃过敏的临床方面和诊断试剂质量的理解。
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