Khalife J, Pierce R J, Godin C, Capron A
Centre d'immunologie et de Biologie Parasitaire, INSERM U 167-CNRS 624, Institut Pasteur, Lille, France.
Parasitology. 1994 Jun;108 ( Pt 5):533-42. doi: 10.1017/s0031182000077404.
We have previously described a rat mAb directed against a peptide derived from the vif protein of HIV-1 that recognized two Schistosoma mansoni (Sm) antigens with a major band at 65 kDa. Epitope mapping of this mAb using overlapping hexapeptides derived from the vif peptide revealed that the motif recognized was PLPSVT. The screening of a Sm cDNA library led to the identification of two clones, Sm70 and Sm65. The two deduced protein sequences did not share any common structural features apart from the epitope recognized by the mAb (see below), and did not show significant identity to sequences present in the data bases. However, the N terminus of the deduced sequence of the Sm70 protein exhibits a consensus sequence known to be an ATP/GTP binding site. Furthermore, the C terminus of the deduced Sm65 protein sequence was found to contain a conserved hexapeptide with a consensus sequence LPETGE reported to be an important motif of the surface proteins of gram-positive cocci. Both proteins exhibit a peptide sequence (PLRSVT for Sm70 and PVGSVT for Sm65) similar to the epitope recognized by the mAb anti-vif. Western blotting experiments showed that the mAb anti-vif reacted with both proteins. However, only Sm65 was recognized by sera from HIV-1-seropositive individuals, whereas both proteins were recognized by S. mansoni-infected patients.
我们之前描述过一种针对源自HIV-1病毒vif蛋白的肽段的大鼠单克隆抗体，该抗体可识别两种曼氏血吸虫（Sm）抗原，其中主要条带位于65 kDa处。使用源自vif肽段的重叠六肽对该单克隆抗体进行表位作图，结果显示所识别的基序为PLPSVT。对曼氏血吸虫cDNA文库的筛选导致鉴定出两个克隆，即Sm70和Sm65。除了该单克隆抗体所识别的表位外（见下文），这两个推导的蛋白质序列没有任何共同的结构特征，并且与数据库中存在的序列没有显著的同一性。然而，Sm70蛋白推导序列的N端显示出一个已知为ATP/GTP结合位点的共有序列。此外，发现推导的Sm65蛋白序列的C端含有一个保守的六肽，其共有序列为LPETGE，据报道这是革兰氏阳性球菌表面蛋白的一个重要基序。这两种蛋白均表现出与抗vif单克隆抗体所识别的表位相似的肽序列（Sm70为PLRSVT，Sm65为PVGSVT）。蛋白质印迹实验表明，抗vif单克隆抗体与这两种蛋白均发生反应。然而，只有Sm65能被HIV-1血清阳性个体的血清识别，而这两种蛋白均可被曼氏血吸虫感染患者的血清识别。
