Gangliosides, sialic acid-containing glycosphingolipids, are ubiquitously expressed in all eukaryotic cells and are primarily localized in the plasma membrane. Cholera toxin B subunit (Ctxb), a component of a heat-labile enterotoxin produced by Vibrio cholerae, has been frequently used as a probe to detect GM1 ganglioside because of its high affinity for this glycolipid. In this study, we evaluated the reactivity of Ctxb and the expression of GM1 in mouse embryonic neuroepithelial cells (NECs). Analysis of Ctxb reactivity of NECs based on flow cytometry revealed that about 80% of the cells are Ctxb positive. A detailed biochemical analysis, however, indicated that GM1 was expressed in NECs in barely detectable quantities. Thus, it was thought that reactivity of Ctxb in the NECs could arise from high-affinity interaction with GM1. Because Ctxb is commonly used as a reagent for flow cytometry and GM1 cell staining, we recommend that using this reagent alone would be inconclusive and that biochemical analysis of GM1 should also be performed to avoid overestimation of GM1 expression and/or mischaracterization of the ganglioside species.

中文翻译：

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霍乱毒素B亚基结合与GM1表达无关：这项使用小鼠胚胎神经前体细胞的研究。

神经节苷脂，一种含有唾液酸的糖鞘脂，在所有的真核细胞中普遍表达，并且主要位于质膜中。霍乱弧菌产生的不耐热肠毒素的成分霍乱毒素B亚基（Ctxb）由于对这种糖脂的亲和力高而经常被用作检测GM1神经节苷脂的探针。在这项研究中，我们评估了Ctxb的反应性和小鼠胚胎神经上皮细胞（NECs）中GM1的表达。基于流式细胞仪分析NEC的Ctxb反应性表明，约80％的细胞为Ctxb阳性。但是，详细的生化分析表明，GM1在NEC中的表达量几乎不可检测。因此，认为NEC中Ctxb的反应性可能源自与GM1的高亲和力相互作用。