Loomes L M, Uemura K, Feizi T
Infect Immun. 1985 Jan;47(1):15-20. doi: 10.1128/iai.47.1.15-20.1985.
The role of sialoglycolipids (gangliosides) as receptors for the human pathogen Mycoplasma pneumoniae was investigated by using purified gangliosides of known carbohydrate structures as inhibitors of the binding of 51Cr-labeled erythrocytes to sheet cultures of M. pneumoniae. We found that sialoglycolipids with long carbohydrate backbones of the poly-N-acetyllactosamine type were more potent inhibitors of M. pneumoniae binding than those with short carbohydrate chains. This is in accord with earlier inhibition data for glycoproteins and oligosaccharides. Thus, the inhibitory activity of a fraction of bovine erythrocyte gangliosides containing long backbone structures of I antigen type was approximately 200 times greater than that of the short chain gangliosides GM3 and GT1b. The binding of M. pneumoniae to erythrocytes of I and i antigen types was found to be comparable, indicating that M. pneumoniae in its adhesive specificity may not distinguish between the branched carbohydrate backbones of I type and the linear structures of i type. Thus, the production of autoantibodies to the backbone structures of I type rather than i type after infection with this agent may simply reflect a greater abundance of branched carbohydrate receptors of I type on the surface of host cells with which the mycoplasma forms immunogenic complexes.
通过使用已知碳水化合物结构的纯化神经节苷脂作为51Cr标记红细胞与肺炎支原体平板培养物结合的抑制剂，研究了唾液酸糖脂（神经节苷脂）作为人类病原体肺炎支原体受体的作用。我们发现，具有多聚N-乙酰乳糖胺型长碳水化合物主链的唾液酸糖脂比具有短碳水化合物链的唾液酸糖脂更有效地抑制肺炎支原体的结合。这与早期关于糖蛋白和寡糖的抑制数据一致。因此，含有I抗原型长主链结构的一部分牛红细胞神经节苷脂的抑制活性比短链神经节苷脂GM3和GT1b大约高200倍。发现肺炎支原体与I和i抗原型红细胞的结合相当，这表明肺炎支原体在其粘附特异性方面可能无法区分I型的分支碳水化合物主链和i型的线性结构。因此，感染该病原体后产生针对I型而非i型主链结构的自身抗体可能仅仅反映了支原体与之形成免疫原性复合物的宿主细胞表面I型分支碳水化合物受体的丰度更高。
