Feldberg Liron, Elhanany Eytan, Laskar Orly, Schuster Ofir
Department of Analytical Chemistry, Israel Institute for Biological Research, Ness Ziona 74100, Israel.
Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness Ziona 74100, Israel.
Toxins (Basel). 2021 Jan 22;13(2):79. doi: 10.3390/toxins13020079.
Ricin, a protein derived from the seeds of the castor bean plant (), is a highly lethal toxin that inhibits protein synthesis, resulting in cell death. The widespread availability of ricin, its ease of extraction and its extreme toxicity make it an ideal agent for bioterrorism and self-poisoning. Thus, a rapid, sensitive and reliable method for ricin identification in clinical samples is required for applying appropriate and timely medical intervention. However, this goal is challenging due to the low predicted toxin concentrations in bio-fluids, accompanied by significantly high matrix interferences. Here we report the applicability of a sensitive, selective, rapid, simple and antibody-independent assay for the identification of ricin in body fluids using mass spectrometry (MS). The assay involves lectin affinity capturing of ricin by easy-to-use commercial lactose-agarose (LA) beads, following by tryptic digestion and selected marker identification using targeted LC-MS/MS (Multiple Reaction Monitoring) analysis. This enables ricin identification down to 5 ng/mL in serum samples in 2.5 h. To validate the assay, twenty-four diverse naive- or ricin-spiked serum samples were evaluated, and both precision and accuracy were determined. A real-life test of the assay was successfully executed in a challenging clinical scenario, where the toxin was identified in an abdominal fluid sample taken 72 h post self-injection of castor beans extraction in an eventual suicide case. This demonstrates both the high sensitivity of this assay and the extended identification time window, compared to similar events that were previously documented. This method developed for ricin identification in clinical samples has the potential to be applied to the identification of other lectin toxins.
蓖麻毒素是一种从蓖麻植物种子中提取的蛋白质，是一种高度致命的毒素，可抑制蛋白质合成，导致细胞死亡。蓖麻毒素广泛可得、易于提取且毒性极强，使其成为生物恐怖主义和自我中毒的理想制剂。因此，为了进行适当及时的医疗干预，需要一种快速、灵敏且可靠的方法来鉴定临床样本中的蓖麻毒素。然而，由于生物流体中预测的毒素浓度较低，同时伴有显著的高基质干扰，这一目标具有挑战性。在此，我们报告了一种灵敏、选择性强、快速、简单且无需抗体的检测方法，该方法利用质谱（MS）鉴定体液中的蓖麻毒素。该检测方法包括使用易于操作的商业乳糖 - 琼脂糖（LA）磁珠通过凝集素亲和捕获蓖麻毒素，随后进行胰蛋白酶消化，并使用靶向液相色谱 - 串联质谱（多反应监测）分析鉴定选定的标志物。这使得在2.5小时内能够鉴定血清样本中低至5 ng/mL的蓖麻毒素。为了验证该检测方法，对24个不同的未接触过蓖麻毒素或添加了蓖麻毒素的血清样本进行了评估，并确定了精密度和准确度。在一个具有挑战性的临床场景中成功进行了该检测方法的实际测试，在一例最终自杀的病例中，在自注射蓖麻籽提取物72小时后采集的腹腔液样本中鉴定出了毒素。与先前记录的类似事件相比，这既证明了该检测方法的高灵敏度，也证明了其延长的鉴定时间窗口。这种为临床样本中蓖麻毒素鉴定而开发的方法有可能应用于其他凝集素毒素的鉴定。
