111Indium-labeled human alveolar macrophages and monocytes: function and ultrastructure.

Human alveolar macrophages and peripheral blood mononuclear cells were labelled with indium-111 (111In)-oxine in ethanol. The efficiency of labeling averaged 84% for macrophages and 74% for mononuclear cell preparations. Phagocytosis by macrophages, the release of colony stimulating factor activity (CSF) by macrophages, and chemotaxis by monocytes in response to human C5-derived chemotactic factor (C5fr) and formyl-methionyl-leucyl-phenylalanine (f-MLP), were indistinguishable between labeled and unlabeled cells. Microscopically, labeled cells looked similar to control cells. Radioautography demonstrated 111In throughout the labeled cells, but there was a disproportionately high quantity over nuclei. These findings add to the growing literature indicating that 111In labels cells efficiently and that cells can retain function after being labeled with 111In.