Neutrophil labeling with indium-111: tropolone vs. oxine

This study was undertaken to compare tropolone with oxine (8-hydroxy-quinoline) for labeling human neutrophils with In-111. Exposure of neutrophils to tropolone at concentrations required for efficient labeling resulted in a marked impairment of chemotaxis. In contrast, no impairment of neutrophil chemotaxis was observed using In-111 oxine. Labeling efficiencies obtained with In-111 tropolone under optimal conditions were consistently less than those obtained with In-111 oxine. We evaluated cells labeled by the two methods using chemotaxis radioassay to assess the chemotatic potential of labeled cells. The results led to the conclusion that the oxine technique is preferable to tropolone for labeling human neutrophils with In-111.