Application Of A Labeled Antibody For Noninvasive Monitoring Of Transplanted Hepatocytes By Near-Infrared (Nir) Imaging

Technologies for in vivo imaging gain significance to monitor distribution and integration of cells for the use in cell therapies during the regeneration of diseased organs. The aim of the study was to identify NIR dyes for visualization of transplanted hepatocytes in vivo in rats. Wild type and CD26‐deficient hepatocytes and livers from wild type Fisher rats were used. A total of six dyes (DY676, 681, 776, 777, 782, 800 emission range 699–801nm) were analyzed using a multispectral imager. For quantification, the Regions‐of‐Interests (ROI) of defined mixtures of CD26‐positive and negative cells were detected. Results were verified by flow cytometry. DY676, 776, 777, 782, 800 yielded non‐specific conjugates with undefined cellular components. DY681 linked to the CD26‐antibody specifically detected CD26‐positive hepatocytes. DY681 displayed ROIs of 372, 375, 244, 102 and 9 [average signal] using defined mixtures of 100%, 85%, 50%, 15% and 0% CD26‐positive cells. Flow cytometry confirmed 99%, 78%, 56%, 21% and 0.2% CD26‐positive cells. Wildtype livers treated in situ with DY681‐CD26 antibody displayed positive signals throughout the whole organ. The DY681‐linked antibody is eligible for the non‐invasive labeling of transplanted hepatocytes. Thus, the hepatic distribution of the cells and repopulation of the liver might be observed, which helps to reduce the amount of animal experiments.