Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Inmunología and Instituto de Estudios de la Inmunidad Humoral Ricardo A. Margni (IDEHU), UBA-CONICET, Buenos Aires, Argentina.
Universidad Nacional de Luján, Departamento de Ciencias Básicas, Luján, Argentina; Universidad Nacional de Luján, Instituto de Ecología y Desarrollo Sustentable (INEDES)-CONICET, Laboratorio de Inmunología, Buenos Aires, Argentina.
Biochem Biophys Res Commun. 2021 Jun 18;558:168-174. doi: 10.1016/j.bbrc.2021.04.077. Epub 2021 Apr 28.
Staphylococcal enterotoxins are one of the most important causative agents of food poisoning. These molecules function as both gastrointestinal toxins and superantigens (SAgs) which can simultaneously bind MHC-II and T cell receptor leading to a non-specific polyclonal T cell activation and massive proinflammatory cytokine release. Common symptoms include vomiting and diarrhea; however, in more severe cases, systemic dissemination may result in toxic shock syndrome and can be lethal in a few hours. Only small amounts of these heat-stable toxins are needed to cause the disease. Therefore, it is highly important to detect quickly low concentrations of SAgs in biological samples. In this work, we report a surface plasmon resonance (SPR)-based capture immunoassay for the detection of the SAg SEG. We analyzed the use of different amplification strategies. The SPR-based double-antibody sandwich approach could detect picomolar levels of SEG. The use of antibody-coated silica nanoparticles (AbSiNPs) as an alternative enhancing reagent also detected SEG in the picomolar range. Although AbSiNPs did not improve the limit of detection, for the same amount of SAg tested, AbSiNPs gave a higher response level than free antibodies. This work highlights the suitability of silica nanoparticles for signal amplification in SPR-based biosensors. Overall, SPR biosensors offer the capability for continuous real-time monitoring and high sensitivity that can be befitting for the detection of enterotoxins in food industries, laboratories and regulatory agencies.
葡萄球菌肠毒素是最重要的食物中毒致病因子之一。这些分子既作为胃肠毒素，又作为超抗原 (SAg) 发挥作用，可同时与 MHC-II 和 T 细胞受体结合，导致非特异性多克隆 T 细胞激活和大量促炎细胞因子释放。常见症状包括呕吐和腹泻；然而，在更严重的情况下，全身播散可能导致中毒性休克综合征，在数小时内可致命。只需少量热稳定毒素即可引发疾病。因此，快速检测生物样本中低浓度的 SAg 非常重要。在这项工作中，我们报告了一种基于表面等离子体共振 (SPR) 的捕获免疫分析，用于检测 SAg SEG。我们分析了不同放大策略的使用。基于 SPR 的双抗体夹心方法可以检测到皮摩尔级别的 SEG。使用涂有抗体的硅纳米颗粒 (AbSiNPs) 作为替代增强试剂也可以在皮摩尔范围内检测到 SEG。虽然 AbSiNPs 没有提高检测限，但对于相同量的测试 SAg，AbSiNPs 比游离抗体产生更高的响应水平。这项工作强调了硅纳米颗粒在基于 SPR 的生物传感器中用于信号放大的适用性。总的来说，SPR 生物传感器提供了连续实时监测和高灵敏度的能力，非常适合食品工业、实验室和监管机构中肠毒素的检测。
