Abstract #1885

Feng J, Meloni M, Allan S, Narvainen J, Faulkner S, Kauppinen R

Macrophages contain tuftsin receptor that functions to internalize tuftsin for cell activation. Tuftsin was used as a lead molecule to tag the bioactive peptide with FITC or DOTA. Both Tb and Gd petide conjugates were obtained using DOTA-tuftsin. FITC-tuftsin was internalized by mouse macrophages as revealed by confocal microscopy. Time-gated fluorometry showed dose-dependency of fluorescence signal from macrophages incubated with Tb-tuftsin. Finally, T1-weighted MRI signal was strongly enhanced in macrophage preparations exposed to Gd-tuftsin. These results indicate that tagged tuftsin-conjugates retain biological function at the tuftsin receptor and may be used to detect macrophage cells by fluorescence imaging or MRI.