Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University, Tianjin 300071, China.
College of Food Science and Engineering, Tianjin University of Science & Technology, Tianjin 300457, China.
Food Chem. 2021 Aug 15;353:129481. doi: 10.1016/j.foodchem.2021.129481. Epub 2021 Mar 6.
The interaction between conventional immunoglobulins (Igs) and the Ig-binding surface proteins of Staphylococcus aureus (S. aureus) have obstructed the development of immuno-assays to detect these bacteria. The current study aimed to select nanobodies (Nbs) recognizing specifically S. aureus and to establish an immuno-assay to uncover S. aureus contaminations in foods. An alpaca was immunized with an inactivated S. aureus strain followed by the construction of a Nb library from which four target-specific Nbs were retrieved. Subsequently, a sandwich ELISA employing the Nb147 and biotinylated-Nb147 pair to capture and to detect S. aureus, respectively, was established to possess a detection limit of 1.4 × 10 colony forming units (CFU)/mL. The dedicated immuno-assay has been verified by detecting 10 CFU/mL of S. aureus in milk samples after an 8 h-enrichment step. This study provides the basis of an easy, reproducible and effective immuno-assay to screen for S. aureus contaminations in foods.
常规免疫球蛋白（Igs）与金黄色葡萄球菌（S. aureus）的 Ig 结合表面蛋白之间的相互作用，阻碍了免疫分析检测这些细菌的发展。本研究旨在筛选特异性识别金黄色葡萄球菌的纳米抗体（Nbs），并建立一种免疫分析方法来检测食品中的金黄色葡萄球菌污染。用灭活的金黄色葡萄球菌菌株对一只羊驼进行免疫，然后从该菌株构建一个纳米抗体文库，从中回收了 4 种靶向特异性纳米抗体。随后，建立了一种夹心 ELISA 方法，使用纳米抗体 147 和生物素化纳米抗体 147 分别用于捕获和检测金黄色葡萄球菌，其检测限为 1.4×10 个菌落形成单位（CFU）/mL。该专用免疫分析方法已通过在 8 小时富集步骤后在牛奶样本中检测到 10 CFU/mL 的金黄色葡萄球菌得到验证。本研究为在食品中筛选金黄色葡萄球菌污染提供了一种简单、可重复和有效的免疫分析方法的基础。
