Imaging of pulmonary granulomas using a photon imager.

To clarify the location of pulmonary granulomas in vivo, we prepared a Mycobacterium tuberculosis H37Rv mutant in which the gene for a green fluorescent protein (GFP) (GFP-H37Rv) was introduced. Five weeks after aerosol infection with GFP-H37Rv, the infected lungs from guinea pigs and mice were subjected to imaging using a photon imager. Pulmonary granulomas more than 1 mm in diameter were localized clearly by the photon imager. Therefore, if a method for binding a dye (GFP, fluorescein isothiocyanate [FITC], etc.) specifically to M. tuberculosis can be developed, it will be possible to visualize granulomas using a photon imager.