Figure 1.

iRFP TG mouse macrophages express fluorescence in vitro. (A) Peritoneal macrophages from iRFP TG and WT mice observed by fluorescence microscope under a Cy5.5 filter. A clear, fluorescent signal was observed only in the iRFP TG macrophages (scale bar, 50 $\mu$m). (B) The observed iRFP signal with an augmenting number of iRFP TG mouse peritoneal macrophages in comparison to 1 × 10⁷ WT peritoneal macrophages by the IVIS spectrum under 710 nm and 760 nm excitation and emission wavelengths, respectively. The number of iRFP TG macrophage cells required to emit a detectable iRFP signal by the spectrum IVIS under the above conditions was determined to be 1 × 10⁵ cells. (C) The observed iRFP signal intensity with the corresponding macrophage number. A gradual increase in iRFP signal was observed with increasing cell number. The signal intensity was measured by the Living Image Software.