Losa G A, Heumann D, Carrel S, von Fliedner V, Mach J P
Lab Invest. 1986 Nov;55(5):573-9.
Common acute lymphoblastic leukemia antigen detected by radioimmunoassay in the serum of patients with common acute lymphoblastic leukemia was found to be exclusively associated with the pellet of the serum samples obtained by ultracentrifugation at 100,000 X g. The pellets were shown to contain membrane vesicles or fragments which were characterized by electron microscopy and determination of enzymatic activity. The pelleted fragments had an apparent diameter ranging between 60 and 260 nm and showed a trilaminar membrane structure. On freeze-fracture preparations, the fragments with concave profile, corresponding to the external fracture face of plasma membrane, displayed an intramembrane particle density (ranging from 0 to 750 particles per micron2) which is similar to that recorded on the corresponding fracture face of intact cells from the common lymphoblastic leukemia antigen positive leukemic cell line (Nalm-1) or of vesicles shed in the culture medium by Nalm-1 cells. Furthermore, analysis of the membrane enzyme marker 5'-nucleotidase in the pellet of patient's sera, showed that the presence of this enzyme correlated with that of common lymphoblastic leukemia antigen, but the quantitative relationship between the two surface constituents was not linear. The results suggest that the two markers are located on the same membrane fragments, but that their individual distribution on the shed fragments is heterogeneous.
通过放射免疫测定法在普通急性淋巴细胞白血病患者血清中检测到的普通急性淋巴细胞白血病抗原，被发现仅与通过100,000×g超速离心获得的血清样品沉淀相关。这些沉淀显示含有膜泡或碎片，通过电子显微镜和酶活性测定对其进行了表征。沉淀的碎片表观直径在60至260nm之间，呈现出三层膜结构。在冷冻断裂制剂上，具有凹面轮廓的碎片，对应于质膜的外断裂面，显示出膜内颗粒密度（范围为每平方微米0至750个颗粒），这与在普通淋巴细胞白血病抗原阳性白血病细胞系（Nalm-1）的完整细胞的相应断裂面上或Nalm-1细胞在培养基中脱落的囊泡上记录的密度相似。此外，对患者血清沉淀中的膜酶标志物5'-核苷酸酶的分析表明，该酶的存在与普通淋巴细胞白血病抗原的存在相关，但这两种表面成分之间的定量关系不是线性的。结果表明这两种标志物位于相同的膜碎片上，但它们在脱落碎片上的各自分布是异质的。
