Jansons V K, Weis P, Chen T, Redwood W R
Cancer Res. 1978 Mar;38(3):530-5.
The in vitro uptake of phospholipid vesicles by mouse leukemia L1210 cells was examined. Liposomes were generated by prolonged ultrasonic dispersion of aqueous dispersions of mixed lipids in the presence of radiolabeled inulin. Multilamellar vesicles were separated from unilamellar vesicles by column chromatography. Vesicle populations were examined by electron microscopy. Neutral vesicles were generated from egg yolk phosphatidylcholine and cholesterol, and surface charge was introduced via either phosphatidylserine or octadecylamine. Uptake, measured as cell-associated radioactivity, was temperature dependent and was strongly decreased by metabolic inhibitors. These results suggested that liposomes are taken up to a major extent by an energy-dependent mechanism. The uptake of liposomes by cells of a young culture was about 2-fold higher than was the uptake of liposomes by cells of a stationary culture. The uptake of positively charged liposomes by cells was about 20-fold higher than that of either neutral or negatively charged vesicles. About one-half of the cell-associated radioactivity transferred by positively charged liposomes could be removed by cell surface treatment with trypsin or neuraminidase or by a short exposure to 0.6 N NaCl.
对小鼠白血病L1210细胞对磷脂囊泡的体外摄取进行了研究。脂质体是通过在放射性标记的菊粉存在下，对混合脂质的水分散体进行长时间超声分散而产生的。通过柱色谱法将多层囊泡与单层囊泡分离。通过电子显微镜检查囊泡群体。中性囊泡由蛋黄磷脂酰胆碱和胆固醇产生，通过磷脂酰丝氨酸或十八烷基胺引入表面电荷。以细胞相关放射性测量的摄取是温度依赖性的，并且被代谢抑制剂强烈降低。这些结果表明，脂质体主要通过能量依赖机制被摄取。年轻培养细胞对脂质体的摄取比静止培养细胞对脂质体的摄取高约2倍。细胞对带正电荷脂质体的摄取比中性或带负电荷囊泡的摄取高约20倍。带正电荷脂质体转移的约一半细胞相关放射性可通过用胰蛋白酶或神经氨酸酶进行细胞表面处理或通过短时间暴露于0.6N NaCl来去除。
