Greer J M, Koerner T A, Hayakawa K, Hardy R R, Kemp J D
Department of Microbiology, University of Iowa College of Medicine, Iowa City 52242.
Glycobiology. 1993 Aug;3(4):391-401. doi: 10.1093/glycob/3.4.391.
Two monoclonal antibodies (mAbs), SM3G11 and SM6C10, can be used to discriminate between functionally distinct murine CD4+ T cell subsets. In this study we use high-performance thin-layer chromatography and immunostaining techniques to show that the 3G11 mAb reacts with two bands of a ganglioside fraction from murine spleen and thymus, and rat spleen. The 6C10 antibody shows no evidence of glycolipid reactivity. The 3G11+ bands have a mobility between those of the reference gangliosides GD1a and GD1b from human brain. The 3G11+ reactive bands were eluted in the disialyl fraction of rat spleen gangliosides using DEAE anion-exchange chromatography. Treatment of spleen gangliosides with endoglycoceramidase eliminates 3G11 antibody binding over time, indicating that the antigen contains a Glc beta 1-1'ceramide linkage, characteristic of a glycosphingolipid. Treatment of thymus or spleen gangliosides with sialidase eliminates binding of 3G11, thus indicating that the 3G11 epitope is dependent on the expression of one or more sialic acid residues. Immunostaining studies with a variety of reagents indicate that the 3G11+ gangliosides: (i) probably do not contain either the asialo-GM1 or the GM1 core structures; (ii) are not recognized by mAbs specific for the oligosaccharides of asialo-GM2, GM2, GD2 and GD3 gangliosides; and (iii) are also not recognized by antibodies or reagents that are specific for several structures representative of other major glycosphingolipid classes. Overall, these studies strongly suggest that the 3G11+ gangliosides have structures that have not been previously recognized in murine lymphoid tissue. Structures that could account for the known properties of the 3G11+ molecules are described. Finally, ways in which the selective expression of 3G11+ gangliosides might be linked to functionally distinct T-cell behaviours are discussed.
两种单克隆抗体（mAb），即SM3G11和SM6C10，可用于区分功能不同的小鼠CD4+ T细胞亚群。在本研究中，我们使用高效薄层色谱法和免疫染色技术表明，3G11单克隆抗体与来自小鼠脾脏、胸腺以及大鼠脾脏的神经节苷脂部分的两条条带发生反应。6C10抗体未显示出糖脂反应性的证据。3G11+条带的迁移率介于来自人脑的参考神经节苷脂GD1a和GD1b之间。使用DEAE阴离子交换色谱法，将3G11+反应性条带从大鼠脾脏神经节苷脂的二唾液酸部分洗脱出来。用内切糖神经酰胺酶处理脾脏神经节苷脂会随着时间的推移消除3G11抗体的结合，这表明该抗原含有β1-1'连接的葡萄糖神经酰胺键，这是糖鞘脂的特征。用唾液酸酶处理胸腺或脾脏神经节苷脂会消除3G11的结合，因此表明3G11表位依赖于一个或多个唾液酸残基的表达。用多种试剂进行的免疫染色研究表明，3G11+神经节苷脂：（i）可能不包含脱唾液酸GM1或GM1核心结构；（ii）不被针对脱唾液酸GM2、GM2、GD2和GD3神经节苷脂寡糖的单克隆抗体识别；（iii）也不被针对其他主要糖鞘脂类别的几种代表性结构的抗体或试剂识别。总体而言，这些研究强烈表明，3G11+神经节苷脂具有以前在小鼠淋巴组织中未被识别的结构。描述了可能解释3G11+分子已知特性的结构。最后，讨论了3G11+神经节苷脂的选择性表达可能与功能不同的T细胞行为相关的方式。
