Lenz R, Pluznik D H
Exp Hematol. 1985 Jul;13(6):539-44.
Our previous studies have shown that preincubation of murine bone marrow (BM) cells with cholera toxin (CT) or with its B subunit inhibited their responsiveness to colony-stimulating factor (CSF). Because ganglioside GM1 is a component of the CT receptor, the present study was undertaken to determine whether gangliosides interact with CSF and therefore might play a role in the binding sites for CSF. Preincubation of CSF with increasing concentrations of bovine-brain mixed gangliosides resulted in decreased numbers of colonies of BM-derived granulocyte-macrophage progenitor cells (CFU-C) in soft agar. The inhibitory effect of the gangliosides could be reduced by increasing the concentrations of CSF. Evidence for direct binding of CSF to gangliosides was obtained by affinity chromatography of CSF on gangliosides-sepharose beads. CSF activity was retained on the beads and could be eluted with 6 M guanidine HCl. Four different individual gangliosides (GM1, GM2, GD1a, GT1b) were tested for their inhibitory effect on CSF-induced clonal growth of CFU-C. GM1 was the most effective with a 50% inhibition (I50) of clonal growth at a concentration of 15 microM. while the other three gangliosides had slight inhibitory activity (I50 at a concentration greater than 100 microM). In addition, preincubation of BM cells with rabbit anti-GM1 antibodies before addition of CSF reduced the clonal growth of CFU-C to 45%. These data indicate that GM1 interacts with CSF and suggest that gangliosides may play a role in the interaction of CSF with CFU-C and that the binding site for CSF on the surface of these cells might either consist of or contain this ganglioside.
我们之前的研究表明，用霍乱毒素（CT）或其B亚基对小鼠骨髓（BM）细胞进行预孵育会抑制它们对集落刺激因子（CSF）的反应性。由于神经节苷脂GM1是CT受体的一个组成部分，因此开展了本研究以确定神经节苷脂是否与CSF相互作用，进而可能在CSF的结合位点中发挥作用。用浓度不断增加的牛脑混合神经节苷脂对CSF进行预孵育，导致软琼脂中BM来源的粒细胞-巨噬细胞祖细胞（CFU-C）的集落数量减少。增加CSF的浓度可降低神经节苷脂的抑制作用。通过将CSF在神经节苷脂-琼脂糖珠上进行亲和层析，获得了CSF与神经节苷脂直接结合的证据。CSF活性保留在珠子上，可用6M盐酸胍洗脱。测试了四种不同的单个神经节苷脂（GM1、GM2、GD1a、GT1b）对CSF诱导的CFU-C克隆生长的抑制作用。GM1最有效，在浓度为15μM时对克隆生长的抑制率为50%（I50），而其他三种神经节苷脂具有轻微的抑制活性（I50浓度大于100μM）。此外，在添加CSF之前用兔抗GM1抗体对BM细胞进行预孵育，可将CFU-C的克隆生长降低至45%。这些数据表明GM1与CSF相互作用，并提示神经节苷脂可能在CSF与CFU-C的相互作用中发挥作用，并且这些细胞表面CSF的结合位点可能由这种神经节苷脂组成或包含这种神经节苷脂。
