COMPARISON OF THE CARBOHYDRATE-BINDING SPECIFICITIES OF CHOLERA-TOXIN AND ESCHERICHIA-COLI HEAT-LABILE ENTEROTOXINS LTH-I, LT-IIA, AND LT-IIB
COMPARISON OF THE CARBOHYDRATE-BINDING SPECIFICITIES OF CHOLERA-TOXIN AND ESCHERICHIA-COLI HEAT-LABILE ENTEROTOXINS LTH-I, LT-IIA, AND LT-IIB
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DOI：
10.1128/iai.56.7.1748-1753.1988
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发表时间：
1988-07-01
影响因子：
3.1
通讯作者：
GINSBURG, V
中科院分区：
文献类型：
--
作者：
FUKUTA, S;MAGNANI, JL;GINSBURG, V
霍乱弧菌和大肠埃希氏菌的不耐热肠毒素在结构和功能上存在相关性。它们是由A和B多肽亚基组成的低聚物。它们与神经节苷脂结合，激活腺苷环化酶。这些毒素形成两个抗原性不同的组；每个组的成员会交叉反应，但不一定是相同的。血清组I包括霍乱毒素(CT)和大肠杆菌I型不耐热肠毒素(LT-I)。Lth-I和LTP-I分别是由人和猪的大肠杆菌菌株产生的LT-I的抗原变异体。血清组II含有大肠杆菌的II型不耐热肠毒素(LT-II)。已经描述了两个抗原性变体，分别命名为LT-IIa和LT-IIb。用免疫染色薄层色谱法和固相放射免疫法分析CT、Lth-I、LT-IIa和LT-IIb与神经节苷脂的结合。这四种毒素具有不同的糖脂结合特性。Lth-I和CT与神经节苷脂GM1结合较强，与神经节苷脂GD1b结合较弱。然而，与CT不同的是，Lth-I还与GM2和asialo GM1结合较弱。Lth-I和CT一样，可能与末端糖序列Gal.beta.1-3GalNAc.beta.1-4(NeuAc.alpha.2-3)Gal.结合。，其中GalNAc为N-乙酰半乳糖胺，NeuAc为N-乙酰神经氨酸。Lt-IIa可能与CT和Lth-I结合的糖序列结合，与GD1b和GD2中一样，对第二个NeuAc的结合有额外贡献。此外，LT-IIa必须与Gal.beta1-3GalNAc结合。。。与GD1a、GT1b和GQ1b中一样，其结合相对不受NeuAc与末端半乳糖残基连接的影响。LT-IIb可能与末端糖序列NeuAc.alpha2-3Gal.beta1-4GalNAc结合。。..，因为它与神经节苷脂GD1a和GT1b结合，而不与GM1结合。
The heat-labile enterotoxins of Vibrio cholerae and Escherichia coli are related in structure and function. They are oligomers consisting of A and B polypeptide subunits. They bind to gangliosides, and they activate adenylate cyclase. The toxins form two antigenically distinct groups; members of each group cross-react but are not necessarily identical. Serogroup I includes cholera toxin (CT) and type I heat-labile enterotoxin (LT-I) of E. coli. LTh-I and LTp-I are antigenic variants of LT-I produced by strains of E. coli from humans and pigs, respectively. Serogroup II contains the type II heat-labile enterotoxin (LT-II) of E. coli. Two antigenic variants designated LT-IIa and LT-IIb have been described. The binding of CT, LTh-I, LT-IIa, and LT-IIb to gangliosides was analyzed by immunostaining thin-layer chromatograms and by solid-phase radioimmunoassay. The four toxins have different glycolipid-binding specificities. LTh-I and CT bind strongly to ganglioside GM1 and less strongly to ganglioside GD1b. However, LTh-I unlike CT, also binds weakly to GM2 and asialo GM1. LTh-I, like CT, probably binds to the terminal sugar sequence Gal.beta.1-3GalNAc.beta.1-4(NeuAc.alpha.2-3)Gal. . ., where GalNAc is N-acetylgalactosamine and NeuAc is N-acetylneuraminic acid. LT-IIa probably binds to the same sugar sequence to which CT and LTh-I bind, with the additional contribution to binding of a second NeuAc as in GD1b and GD2. Also, LT-IIa must bind the Gal.beta.1-3GalNAc. . . sequence in such a way that its binding is relatively unaffected by attachment of NeuAc to the terminal galactose residue as in GD1a, GT1b, and GQ1b. LT-IIb probably binds to the terminal sugar sequence NeuAc.alpha.2-3Gal.beta.1-4GalNAc . . ., as it binds to gangliosides GD1a and GT1b but not to GM1.