Comparison of 111In-oxine and 111In-Acetylacetone for the labeling of cells: in vivo and in vitro biological testing

We have compared several complexes of indium as cell labels: indium-111-acetylacetone, indium-111-oxine, and indium-111-chloride complexed with 8-hydroxyquinoline (oxine) immediately prior to use. In labelling with acetylacetone, it was shown that the labeling efficiency is directly proportional to the amount of acetylacetone present, but the cell viability (as measured by in vitro aggregation studies), is inversely proportional to the amount of acetylacetone present. Biological studies were carried out in dogs using indium-111-labeled platelets; survival times and recovery values obtained with platelets labeled using all three techniques were similar. The same solutions were also used to label white blood cells; labeling efficiencies of greater than 80% were obtained in all cases, and the viability (as measured by trypan blue exclusion) was high in all cases. Chemotactic ability of the white cells labeled with indium-111-oxine is higher than that of unlabeled control cells; however, cells labeled with indium-111-acetylacetone were the same as the unlabeled control cells.