Scientific Publications by FDA Staff

Free Radic Res 2008 Jan;42(1):49-56

Spin labelling of Bacillus anthracis endospores: a model for in vivo tracking by EPR imaging.

Tsai P, Cao GL, Merkel TJ, Rosen GM

Rosen, GM (reprint author), Univ Maryland, Sch Pharm, Dept Pharmaceut Sci, 725 W Lombard St, Baltimore, MD 21201 USA Univ Maryland, Sch Pharm, Dept Pharmaceut Sci, Baltimore, MD 21201 USA Univ Maryland, Ctr Med Biotechnol, Inst Biotechnol, Baltimore, MD 21201 USA Univ Maryland, Sch Pharm, Ctr EPR Imaging Vivo Physiol, Baltimore, MD 21201 USA US FDA, Lab Resp & Special Pathogens, Ctr Biol Evaluat & Res, Bethesda, MD 20892 USA

Anthrax is caused by the gram-negative bacterium, Bacillus anthracis. Infection by this microbe results from delivery of the endospore form of the bacillus through direct contact, either topical or inhalation. With regard to the latter route of administration, it is proposed that endospores of B. anthracis enter the lungs and are phagocytized by host alveolar macrophages. Thereafter, it is unclear as to how endospores travel to distal loci and what tissues are the targets. Herein, this study describes the spin labelling of endospores through two different approaches with various aminoxyls. Indeed, after exposure to RAW 264.7 cells, these aminoxyl-containing endospores were phagocytized, as demonstrated by EPR spectroscopy of the infected macrophage, thus providing a potential tool for EPR imaging in animals.