Office of Regulatory Science, Center for Food Safety and Applied Nutrition (CFSAN), Food and Drug Administration, 5001 Campus Drive, College Park, MD, 20740, USA.
Radix® BioSolutions, Georgetown, TX, 78626, USA.
Anal Bioanal Chem. 2018 Sep;410(23):5791-5806. doi: 10.1007/s00216-018-1187-3. Epub 2018 Jun 18.
Food allergies affect some 15 million Americans. The only treatment for food allergies is a strict avoidance diet. To help ensure the reliability of food labels, analytical methods are employed; the most common being enzyme-linked immunosorbent assays (ELISAs). However, the commonly employed ELISAs are single analyte-specific and cannot distinguish between false positives due to cross-reactive homologous proteins; making the method of questionable utility for regulatory purposes when analyzing for unknown or multiple food allergens. Also, should the need arise to detect additional analytes, extensive research must be undertaken to develop new ELISAs. To address these and other limitations, a multiplex immunoassay, the xMAP® food allergen detection assay (xMAP FADA), was developed using 30 different antibodies against 14 different food allergens plus gluten. Besides incorporating two antibodies for the detection of most analytes, the xMAP FADA also relies on two different extraction protocols; providing multiple confirmatory end-points. Using the xMAP FADA, the cross-reactivities of 45 botanicals used in dietary supplements and spices commercially sold in the USA were assessed. Only a few displayed cross-reactivities with the antibodies in the xMAP FADA at levels exceeding 0.0001%. The utility of the xMAP FADA was exemplified by its ability to detect and distinguish between betel nut, saw palmetto, and acai which are in the same family as coconut. Other botanicals examined included allspice, amchur, anise seed, black pepper, caraway seed, cardamom, cayenne red pepper, sesame seed, poppy seed, white pepper, and wheat grass. The combination of direct antibody detection, multi-antibody profiling, high sensitivity, and a modular design made it possible for the xMAP FADA to distinguish between homologous antigens, provide multiple levels of built-in confirmatory analysis, and optimize the bead set cocktail to address specific needs.
食物过敏影响了约 1500 万美国人。食物过敏的唯一治疗方法是严格避免食用相关食物。为了帮助确保食品标签的可靠性，采用了分析方法；最常见的是酶联免疫吸附测定法（ELISA）。然而，常用的 ELISA 是单一分析物特异性的，不能区分由于交叉反应同源蛋白引起的假阳性；这使得该方法在分析未知或多种食物过敏原时的实用性受到质疑。此外，如果需要检测额外的分析物，必须进行广泛的研究来开发新的 ELISA。为了解决这些和其他限制，开发了一种多重免疫分析，即 xMAP®食物过敏原检测分析（xMAP FADA），该分析使用了针对 14 种不同食物过敏原加谷蛋白的 30 种不同抗体。除了包含两种用于检测大多数分析物的抗体外，xMAP FADA 还依赖于两种不同的提取方案；提供多个确认终点。使用 xMAP FADA，评估了在美国商业销售的膳食补充剂和香料中使用的 45 种植物的交叉反应性。只有少数几种在 xMAP FADA 中的抗体的交叉反应性超过 0.0001%。xMAP FADA 的实用性体现在它能够检测和区分在同一科中的槟榔、锯棕榈和巴西莓，而其他检查的植物包括多香果、酸角、八角茴香种子、黑胡椒、葛缕子、豆蔻、卡宴红辣椒、芝麻、罂粟籽、白胡椒和小麦草。直接抗体检测、多抗体分析、高灵敏度和模块化设计的结合，使得 xMAP FADA 能够区分同源抗原，提供内置确认分析的多个层次，并优化珠子组鸡尾酒以满足特定需求。
