Shaposhnikova G I, Prokazova N V, Buznikov G A, Zvezdina N D, Teplitz N A, Bergelson L D
Eur J Biochem. 1984 May 2;140(3):567-70. doi: 10.1111/j.1432-1033.1984.tb08139.x.
The ganglioside composition of mouse ascites hepatoma ( MAH ) cells, the ascites fluid and cell-conditioned media were determined and found to be qualitatively identical, but quantitatively different. The ganglioside content of the ascites fluid and the medium conditioned by MAH -cells at the native cell concentration (10(8) cells/ml) comprised respectively 74.9% and 23% of the cell-associated gangliosides. When incubated at lower cell-density (10(6) cells/ml) the cells were found to be release about three-times higher amounts of ganglioside per cell than during incubation at the native concentration. Centrifugation of the dense-cell-conditioned medium revealed the major part of the released gangliosides to be associated with a 150000 X g pellet that probably contains shed plasma membrane fragments. In the 150000 X g pellet of the extracellular fluids the relative content of the most polar cell ganglioside corresponding chromatographically to GT1b was about ten-times higher than in the cells. The possibility is raised that the more intense shedding of gangliosides from less crowded MAH cells may play a role in the self protection of the tumor from host immune rejection during initial stages of growth.
对小鼠腹水肝癌（MAH）细胞、腹水及细胞条件培养基中的神经节苷脂成分进行了测定，发现其在定性上相同，但在定量上存在差异。腹水以及由天然细胞浓度（10⁸个细胞/毫升）的MAH细胞所条件培养的培养基中的神经节苷脂含量，分别占细胞相关神经节苷脂的74.9%和23%。当在较低细胞密度（10⁶个细胞/毫升）下培养时，发现细胞释放的神经节苷脂量比在天然浓度下培养时每个细胞高出约三倍。对高密度细胞条件培养基进行离心后发现，释放出的神经节苷脂的主要部分与一个150000×g沉淀相关，该沉淀可能包含脱落的质膜片段。在细胞外液的150000×g沉淀中，色谱上对应于GT1b的最具极性的细胞神经节苷脂的相对含量比在细胞中高出约十倍。由此提出一种可能性，即来自较不密集的MAH细胞的神经节苷脂更强烈的脱落可能在肿瘤生长初期对宿主免疫排斥的自我保护中发挥作用。
