Detection of Ricin in Complex Samples by Immunocapture and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry

详细信息    查看全文

• 作者：Elodie Duriez ; Franç ; ois Fenaille ; Jean-Claude Tabet ; Patricia Lamourette ; Didier Hilaire ; Franç ; ois Becher ; Eric Ezan
• 刊名：Journal of Proteome Research
• 出版年：2008
• 出版时间：September 5, 2008
• 年：2008
• 卷：7
• 期：9
• 页码：4154-4163
• 全文大小：438K
• 年卷期：v.7,no.9(September 5, 2008)
• ISSN：1535-3907

文摘

Ricin, the toxin component of Ricinus communis is considered as a potential chemical weapon. Several complementary techniques are required to confirm its presence in environmental samples. Here, we report a method combining immunocapture and analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the accurate detection of different species of R. communis. Liquid environmental samples were applied to magnetic particles coated with a monoclonal antibody directed against the B-chain of the toxin. After acidic elution, tryptic peptides of the A- and B-chains were obtained by accelerated digestion with trypsin in the presence of acetonitrile. Of the 20 peptides observed by MALDI-TOF MS, three were chosen for detection (m/z 1013.6, m/z 1310.6 and m/z 1728.9, which correspond to peptides 161-LEQLAGNLR-169, 150-YTFAFGGNYDR-160, and 233-SAPDPSVITLENSWGR-248, respectively). Their selection was based on several parameters such as detection sensitivity, specificity toward ricin forms and absence of isotopic overlap with unrelated peptides. To increase assay reproducibility, stable isotope-labeled peptides were incorporated during the sample preparation phase. The final assay has a limit of detection estimated at ∼50 ng/mL (∼0.8 nM) of ricin in buffer. No interference was observed when the assay was applied to ricin-spiked milk samples. In addition, several varieties of R. communis or from different geographical origins were also shown to be detectable. The present assay provides a new tool with a total analytical time of ∼5 h, which is particularly relevant in the context of a bioterrorist incident.