Department of Biochemistry and Nutrition, CSIR-Central Food Technological Research Institute, Mysore, India.
Mol Nutr Food Res. 2014 Apr;58(4):894-902. doi: 10.1002/mnfr.201300261. Epub 2013 Dec 5.
Cases of oral allergy syndrome following the ingestion of sapodilla plum (Manilkara zapota) have been reported rarely. As the causative allergens are not known, the main objective of this study was to identify and characterize the important allergens in sapodilla.
Allergy to sapodilla was diagnosed by case history, skin prick test, and serum allergen-specific IgE. The allergen was detected by IgE immunoblotting, purified on SP-Sepharose and characterized by native/SDS-PAGE, IEF, MS, and amino acid composition. Several cases of allergy to sapodilla fruit were identified; majority of the sapodilla-allergic subjects (6/7) experienced typical oral allergy syndrome symptoms, and allergen-specific IgE to the purified protein was positive. The allergen has a pI ≥9.5 and high contents of arginine, threonine, glycine, and cysteine. Circular dichroism revealed a secondary structure rich in beta sheets/turns. Based on its N-terminal sequence of A-T-F-D-I-Q-N-N-C-X-Y-, the allergen (21 578 Da) was identified as a thaumatin-like protein by homology.
The causative allergen in sapodilla plum has been identified and characterized as a highly basic thaumatin-like protein belonging to the pathogenesis-related protein (PR-5) family, which has been recognized as a new family of conserved, cross-reactive plant allergens.
食用萨帕塔鳄梨树（Manilkara zapota）后出现口腔过敏综合征的病例很少见。由于未知致病过敏原，本研究的主要目的是鉴定和分析鳄梨树中的重要过敏原。
通过病例史、皮肤点刺试验和血清过敏原特异性 IgE 诊断对鳄梨树过敏。通过 IgE 免疫印迹检测过敏原，在 SP-Sepharose 上纯化，并通过天然/SDS-PAGE、IEF、MS 和氨基酸组成进行表征。鉴定出几例鳄梨树过敏病例；大多数鳄梨树过敏患者（6/7）出现典型的口腔过敏综合征症状，且对纯化蛋白的过敏原特异性 IgE 呈阳性。过敏原的等电点（pI）≥9.5，精氨酸、苏氨酸、甘氨酸和半胱氨酸含量高。圆二色性显示富含β片/转折的二级结构。根据其 N 端序列 A-T-F-D-I-Q-N-N-C-X-Y-，过敏原（21578 Da）通过同源性鉴定为一种硫氧还蛋白样蛋白。
已鉴定和分析出鳄梨树中的致敏原，其为一种高度碱性的硫氧还蛋白样蛋白，属于与发病机制相关蛋白（PR-5）家族，该家族已被认为是一种保守的、交叉反应性植物过敏原的新家族。
