[111In]oxine labelling of polymorphonuclear leucocytes: doubts concerning elution and effects on cell behaviour

Polymorphonuclear leucocytes (PMN) from normal human subjects were labelled with [111In]oxine (20 muCi 10(8) cells). In the presence of 20% autologous serum (AS), dissociation of 111In from the cells resulted in mean losses of radioactivity of 13% at 3 h and 30% at 24 h. Adherence of 111In-labelled PMN to cultured porcine endothelial monolayers was increased by 40.7 +/- 31.6% after 60 min incubation in 20% AS at 37 degrees C when compared with unlabelled cells. Phagocytosis and intracellular killing of Candida albicans were unaltered by labelling. Elution of 111In from labelled PMN together with enhanced adhesiveness may have important implications for the study of PMN kinetics and the investigation of inflammatory disease.