title: Sensitive detection of Bacillus anthracis spores by immunocapture and liquid chromatography-tandem mass spectrometry.
abstract: Bacillus anthracis  is one of the most dangerous agents of the bioterrorism threat. We present here a sensitive immuno-liquid chromatography-tandem mass spectrometry (immuno-LC-MS/MS) approach to spore detection in complex environmental samples. It is based on the combined specificity and sensitivity of two techniques: immunocapture and targeted mass spectrometry. The immunocapture step, realized directly on the intact spores, is essential for their selective isolation and concentration from complex environmental samples. After parallel trypsin and Glu-C digestions, proteotypic peptides corresponding to small acid-soluble spore protein-B (SASP-B) are specifically monitored in the multiple reaction monitoring (MRM) mass spectrometry mode. Peptide ratio is carefully monitored and provides an additional level of specificity, which is shown to be highly useful for distinguishing closely related samples and avoiding false-positive/negative results. Sensitivity at the level of the infectious dose is demonstrated, with limits of detection of 7 × 10(3) spores/mL of milk or 10 mg of soil. This mass spectrometry approach is thus complementary to polymerase chain reaction (PCR) techniques.
authors.affiliation: Service de Pharmacologie et d'Immunoanalyse, iBiTec-S, CEA, Gif-sur-Yvette Cedex, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Chenau
authors.forename: François
authors.initials: F
authors.lastname: Fenaille
authors.forename: Eric
authors.initials: E
authors.lastname: Ezan
authors.forename: Nathalie
authors.initials: N
authors.lastname: Morel
authors.forename: Patricia
authors.initials: P
authors.lastname: Lamourette
authors.forename: Pierre L
authors.initials: PL
authors.lastname: Goossens
authors.forename: François
authors.initials: F
authors.lastname: Becher
mesh_terms: D001408:Bacillus anthracis / Q000737:chemistry* / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid; D004797:Enzyme-Linked Immunosorbent Assay; D053719:Tandem Mass Spectrometry