Site-specific labeling of 'second generation' annexin V with Tc-99m(CO)(3) for improved imaging of apoptosis in vivo

In this study 'second generation' AnxV was specifically labeled with Tc-99m in three different ways outside the binding region of the protein to obtain an improved target-to-background activity ratio. The compounds were tested in vitro and in vivo in normal mice and in a model of hepatic apoptosis (anti-Fas mAb). The apoptosis binding was most prominent for the HIS-tagged 'second generation' AnxV labeled with Tc-99m(CO)(3) in comparison to Tc-99m-HYNIC-cys-AnxV and Tc-99m(CO)(3)-DTPA-cys-AnxV.