Abstract
Autoradiography of smears and frozen sections of labelled cell suspensions was used to study the distribution of radioactivity in and among blood cells labelled in either whole blood or leucocyte-rich plasma (LRP) with technetium-99m-SnF2 colloid. The tracer proved selective for neutrophils: the labelling probability (relative to that for erythrocytes) for each cell type in LRP (mean of five samples) was: neutrophils, 9.4; lymphocytes, 3.7; monocytes, 3.0; eosinophils 1.4; erythrocytes, 1.0. When labelling was carried out in whole blood (five samples), 74.5%±8.3% of the cell-bound radioactivity was bound to erythrocytes, 13.6%±6.5% to neutrophils, and 11.9%±2.1% to lymphocytes, whereas in LRP (in which the leucocytes were only slightly out-numbered by erythrocytes), 76.5%±14.9% of radioactivity was neutrophil bound. Labelled cells in smear autoradiographs exhibited two distinct silver grain patterns, “diffuse”, consistent with an intracellular radioactive particle (in neutrophils), and “focal”, consistent with a cell surface-adhering particle in direct contact with the emulsion (in other leucocyte types and erythrocytes). The phagocytic inhibitor cytochalasin B neither reduced the proportion of labelled neutrophils nor altered the labelling pattern. Neutrophils were able to scavenge radioactivity from the surface of erythrocytes. It is concluded that neutrophils bind99mTc-SnF2 intracellularly by phagocytosis, with high affinity; other cells become labelled at the cell surface reversibly and with lower affinity. This selectivity is high enough to permit predominantly leucocyte labelling in LRP but not in whole blood.
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References
Fisher CH, Scheffel U, Tsan MF, Rhodes BA, Wagner HN. Leukocyte tagging by phagocytosis of Tc-99m HSA microspheres. Use in localisation of experimental abscesses by external scanning.J Nucl Med 1975; 16: 527.
McAfee JG, Thakur ML. Survey of radioactive agents for in vitro labeling of phagocytic nucleocytes. II. Particles.J Nucl Med 1976; 17: 488–492.
Thakur ML, Coleman RE, Welch MJ. Indium-111-labeled leucocytes for the localisation of abscesses: preparation, analysis, tissue distribution, and comparison with gallium-67 citrate in dogs.J Lab Clin Med 1977; 89: 217–228.
Peters AM, Danpure HJ, Osman S, et al. Clinical experience with Tc-99m hexamethylpropyleneamineoxime for labelling leucocytes and imaging inflammation.Lancet 1986; 11: 946–949.
Hanna R, Braun T, Levendel A, Lomas F. Radiochemistry and biostability of autologous leucocytes labelled with Tc-99m-stannous colloid in whole blood.Eur J Nucl Med 1984; 9: 216–219.
Hanna R, Lomas F. Identification of factors affecting technetium 99m leucocyte labelling by phagocytic engulfment and development of an optimal technique.Eur J Nucl Med 1986; 12: 159–162.
Mock BH, English D. Leukocyte labeling with technetium-99m tin colloids.J Nucl Med 1987; 28: 1471–1477.
Rogers AW.Techniques of autoradiography, 2nd edn. Amsterdam: Elsevier/North Holland, 1979.
Puncher MRB, Blower PJ. Radionuclide targeting and dosimetry at the microscopic level: the role of microautoradiography.Eur J Nucl Med 1994; 21: 1347–1365.
Radpharmn Scientific leucocyte labelling kit, package insert, 1994, Radpharm Scientific, PO Box 223, Kippax ACT, Australia 2615.
Mountford PJ, Kettle AG, O'Doherty MJ, Coakley AJ. Comparison of technetium-99m-HM-PAO leukocytes with indium-111-oxine leukocytes for localizing intraabdominal sepsis.J Nucl Med 1990; 31: 311–315.
Hymer WC, Kuff EL. Isolation of nuclei from mammalian tissues through the use of Triton X-100.J Histochem Cytochem 1964; 12: 359–363.
Puncher MRB, Blower PJ. Frozen section microautoradiography in the study of radionuclide targeting: application to In-111-oxine labeled leukocytes.J Nucl Med 1995 (to be published).
Puncher MRB, Blower PJ. Autoradiography and density gradient separation of Tc-99m-Exametazime (HMPAO) labelled leucocytes reveals selectivity for eosinophils.Eur J Nucl Med 1994; 21: 1175–1182.
Berger MJ. Distribution of absorbed dose around point sources of electrons and beta particles in water and other media. MIRD Pamphlet no. 7.J Nucl Med 1971; 12(Suppl): 5–23.
Shortman K, Williams N, Jackson H, Russel P, Byrt P, Diener E. The separation of different cell classes from lymphoid organs.J Cell Biol 1971; 48: 566–579.
Malawista SE, Gee JBL, Bensch KG. Cytochalasin B reversibly inhibits phagocytosis: functional, metabolic, and ultrastructural effects in human blood leucocytes and rabbit alveolar macrophages.Yale J Biol Med 1971; 44: 286–300.
Baker RJ, Hanna RW, Lomas F, Bartholomeusz D, Sullivan P, Chatterton B. Clinical appraisal of99mTc leucocytes labelled by stannous colloid phagocytosis. In: Nicolini M, Bandoli G, Mazzi U, eds. Proceedings of the third international symposium on technetium in chemistry and nuclear medicine. Verona: Cortina International; New York: Raven Press; 1991: 741–748.
Axline SG, Reaven SG. Inhibition of phagocytosis and plasma membrane mobility of the cultivated macrophage by cytochalasin B.J Cell Biol 1974; 62: 647–659.
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Puncher, M.R.B., Blower, P.J. Labelling of leucocytes with colloidal tech netium-99m-SnF2: an investigation of the labelling process by autoradiography. Eur J Nucl Med 22, 101–107 (1995). https://doi.org/10.1007/BF00838938
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DOI: https://doi.org/10.1007/BF00838938