Fate of mouse macrophages radiolabelled with PKH-95 and injected intravenously.
Mouse macrophages purified by elutriation from thioglycollate-induced peritoneal exudate cells were labelled with indium-111-oxine and injected intravenously into mice. A substantial amount of unbound radioactivity remained in the circulation, suggesting that the radionuclide was not stably bound to the cells. Culture experiments with radiolabelled cells showed that indium-111 was released in the medium. Another cell marker, PKH-95, an iodine-125-labelled aliphatic compound insertable into the cell membrane, bound more stably than indium-111. Five minutes after injection of 125I-PKH-95-labelled macrophages, about 98% of the cells were in a non-circulating pool. It was checked that PKH-95 labelling did not compromise the viability and functions of the macrophages and that autologous erythrocytes and blood mononuclear cells labelled with PKH-95 remained in the circulation after i.v. injection. One hour after injection, 125I-PKH-95-labelled macrophages were distributed mainly in lung (36%), liver (19%) and spleen (5%). Subsequently, radioactivity decreased in the lung while increasing in liver, spleen and in an artificially induced footpad inflammation. The radioactivity accumulation in the inflammation persisted at least for 7 days. It represented a small proportion of radioactivity injected (0.2%) but was trapped very specifically in the inflammation. This raised the hypothesis that macrophages of the non-circulating pool could be released in the circulation and recruited into the inflammation with slow kinetics.
Centre régional de lutte contre le cancer, Rennes, France.
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Audran
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Collet
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A
Moisan
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Toujas
D000818:Animals; D002470:Cell Survival; D002478:Cells, Cultured; D004912:Erythrocytes / Q000166:cytology / Q000502:physiology*; D005456:Fluorescent Dyes / Q000493:pharmacokinetics; D007205:Indium Radioisotopes; D007457:Iodine Radioisotopes; D007700:Kinetics; D008214:Lymphocytes / Q000166:cytology / Q000502:physiology*; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009930:Organic Chemicals; D009942:Organometallic Compounds / Q000493:pharmacokinetics; D015125:Oxyquinoline / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D011865:Radioisotope Dilution Technique; D013997:Time Factors; D014018:Tissue Distribution
D005456:Fluorescent Dyes; D007205:Indium Radioisotopes; D007457:Iodine Radioisotopes; D009930:Organic Chemicals; D009942:Organometallic Compounds; C070059:PKH 95; C032950:indium oxine; D015125:Oxyquinoline