Puncher M R, Blower P J
Biological Laboratory, The University, Canterbury, UK.
Eur J Nucl Med. 1995 Feb;22(2):101-7. doi: 10.1007/BF00838938.
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 outnumbered 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 bind 99mTc-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.
利用标记细胞悬液涂片和冰冻切片的放射自显影技术，研究了用锝-99m-氟化亚锡胶体标记全血或富白细胞血浆（LRP）中的血细胞时，放射性在血细胞内及血细胞间的分布情况。结果表明，该示踪剂对中性粒细胞具有选择性：LRP（五个样本的平均值）中每种细胞类型的标记概率（相对于红细胞）分别为：中性粒细胞9.4；淋巴细胞3.7；单核细胞3.0；嗜酸性粒细胞1.4；红细胞1.0。当在全血中进行标记时（五个样本），74.5%±8.3%的细胞结合放射性与红细胞结合，13.6%±6.5%与中性粒细胞结合，11.9%±2.1%与淋巴细胞结合；而在LRP中（其中白细胞数量仅略少于红细胞），76.5%±14.9%的放射性与中性粒细胞结合。涂片放射自显影中的标记细胞呈现出两种不同的银粒模式：“弥散型”，与细胞内放射性颗粒一致（存在于中性粒细胞中）；“灶型”，与直接接触乳剂的细胞表面附着颗粒一致（存在于其他白细胞类型和红细胞中）。吞噬抑制剂细胞松弛素B既未降低标记中性粒细胞的比例，也未改变标记模式。中性粒细胞能够从红细胞表面清除放射性。研究得出结论，中性粒细胞通过吞噬作用在细胞内以高亲和力结合99mTc-SnF2；其他细胞在细胞表面可逆性结合且亲和力较低。这种选择性足够高，使得在LRP中主要标记白细胞，而在全血中则不然。
