LYTIC ANTI-ALPHA-GALACTOSYL ANTIBODIES FROM PATIENTS WITH CHRONIC CHAGAS-DISEASE RECOGNIZE NOVEL O-LINKED OLIGOSACCHARIDES ON MUCIN-LIKE GLYCOSYL-PHOSPHATIDYLINOSITOL-ANCHORED GLYCOPROTEINS OF TRYPANOSOMA-CRUZI
LYTIC ANTI-ALPHA-GALACTOSYL ANTIBODIES FROM PATIENTS WITH CHRONIC CHAGAS-DISEASE RECOGNIZE NOVEL O-LINKED OLIGOSACCHARIDES ON MUCIN-LIKE GLYCOSYL-PHOSPHATIDYLINOSITOL-ANCHORED GLYCOPROTEINS OF TRYPANOSOMA-CRUZI
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DOI：
10.1042/bj3040793
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发表时间：
1994-12-15
影响因子：
4.1
通讯作者：
TRAVASSOS, LR
中科院分区：
文献类型：
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作者：
ALMEIDA, IC;FERGUSON, MAJ;TRAVASSOS, LR
慢性恰加斯病(美国锥虫病)患者的血清中含有较高水平的能溶解克氏锥虫的抗α-半乳糖抗体。这些抗体识别的克氏锥虫F2/3抗原复合体在SDS/PAGE上表现为广泛的涂片[Almeida，Krautz，Krettli和Travessos(1993)J.Clin]。实验室。肛门。7,307-316]。用细菌磷脂酰肌醇特异性磷脂酶C(PI-PLC)处理克氏毛滴虫细胞后，它们对慢性恰加斯病(Chagasic，CH)抗-α-半乳糖抗体(anti-Gal)的反应性大部分丧失。经溶剂提取和疏水作用层析纯化的F2/3抗原复合体含有60%的碳水化合物和大量的Thr、Ser、Glx、Asx、Gly、Ala和Pro，但疏水氨基酸相对较少。肌醇、乙醇胺和1-O-十六烷基甘油的存在表明糖基磷脂酰肌醇膜锚的存在。PI-PLC处理证实了这一点，它使F2/3分子具有亲水性并对抗(交叉反应决定簇)抗体起反应。F2/3抗原的GlcNAc主要位于与苏氨酸残基O-糖苷键的低聚糖的还原末端。这些O-连接的寡糖可以通过β-消除和温和的联氨分解来释放。与CH-抗Gal反应的最小释放的寡糖醇是Galα1-3Galβ1-4GlcNAol(GlcNAol是N-乙酰氨基葡萄糖醇)。还观察到了其他几种含半乳糖的寡糖醇，其中大多数是支化的，在还原末端含有4，6-二氧取代的谷氨酰胺醇。所释放的寡糖醇中约有一半可与固定化CH抗半乳糖结合，但无一能与正常人血清中的抗半乳糖结合。这些数据表明，CH抗Gal的特异性与从正常人血清中分离的天然抗Gal有很大不同。因此，这些新型的克氏锥虫O-连接低聚糖在自然感染条件下具有高度的免疫原性，是裂解CH抗半乳糖的靶标。
Sera of patients with chronic Chagas' disease (American trypanosomiasis) contain elevated levels of anti-alpha-galactosyl antibodies that are lytic to Trypanosoma cruzi. The T. cruzi trypomastigote F2/3 antigen complex recognized by these antibodies runs as a broad smear on SDS/PAGE [Almeida, Krautz, Krettli and Travassos (1993) J. Clin. Lab. Anal. 7, 307-316]. Treatment of T. cruzi trypomastigote cells with bacterial phosphatidylinositol-specific phospholipase C (PI-PLC) abolished most of their reactivity to chronic Chagas'-disease ((Chagasic, Ch) anti-alpha-galactosyl antibodies (anti-Gal). The F2/3 antigen complex, purified by solvent extraction and hydrophobic-interaction chromatography, contained 60% carbohydrate by weight and substantial amounts of Thr, Ser, Glx, Asx, Gly, Ala and Pro, but relatively few hydrophobic amino acids. The presence of myoinositol, ethanolamine and 1-O-hexadecylglycerol suggested the presence of glycosyl-phosphatidylinositol membrane anchors. This was confirmed by PI-PLC treatment, which rendered the F2/3 molecules hydrophilic and reactive to anti-(cross-reacting determinant) antibodies. The majority of the GlcNAc content of the F2/3 antigens was found at the reducing termini of oligosaccharides in O-glycosidic linkage to Thr residues. These O-linked oligosaccharides could be released by beta-elimination and by mild hydrazinolysis. The smallest released oligosaccharitol that was reactive with the Ch anti-Gal was Gal alpha 1-3Gal beta 1-4GlcNAcol (where GlcNAcol is N-acetyl-glucosaminitol). Several other Gal-containing oligosaccharitols were observed, most of which were branched and contained 4,6-di-O-substituted GlcNAcol at their reducing termini. About half of the total released oligosaccharitols could bind to immobilized Ch anti-Gal, but none of them bound to the anti-Gal isolated from normal human sera. These data suggest that the specificities of the Ch anti-Gal are quite different from the natural anti-Gal isolated from normal human sera. Therefore, these novel T. cruzi O-linked oligosaccharides are highly immunogenic under the conditions of natural infection and are the targets for lytic Ch anti-Gal.