Taniguchi Y, Zolla-Pazner S, Xu Y, Zhang X, Takeda S, Hattori T
Laboratory of Virus Immunology, Kyoto University, Kyoto, 606-8507, Japan.
Virology. 2000 Aug 1;273(2):333-40. doi: 10.1006/viro.2000.0436.
A mixture of two peptides from gp41 (N36 and C34) forms an alpha-helical structure that is thought to represent the fusogenic form of gp41. A human anti-gp41 monoclonal antibody (mAb 98-6), generated from the cells of an infected individual, reacted poorly with C34, but binding was strongly enhanced when N36 was added, indicating that the mAb reacts with a conformational epitope present in the fusogenic structure formed by the interaction of peptides N36 and C34. The epitope recognized by mAb 98-6 was found in lysates of virions on oligomeric forms of gp41 (dimers, trimers, and tetramers). On infected cells, the epitope was present as oligomers of gp41, as monomers of gp41, and as part of the envelope polyprotein gp160, obtained after biotinylation of intact cells, which were then lysed and immunoprecipitated with various mAbs. In lysates of infected cells, the epitope was present as part of both monomeric gp41 and gp160. These studies demonstrate that infected humans can respond to the fusogenic form of gp41 and that the anti-gp41 mAb studied here recognizes a conformational epitope formed by the interaction of two regions of gp41, which forms an alpha-helical bundle. This epitope is found on several forms of gp41 as it occurs in virions, on the surface of infected cells, and in infected cells.
来自gp41的两种肽（N36和C34）的混合物形成一种α-螺旋结构，该结构被认为代表gp41的融合形式。一种从受感染个体的细胞产生的人抗gp41单克隆抗体（mAb 98-6）与C34反应较差，但当加入N36时结合力大大增强，这表明该单克隆抗体与由肽N36和C34相互作用形成的融合结构中存在的构象表位发生反应。在病毒粒子裂解物中，mAb 98-6识别的表位存在于gp41的寡聚体形式（二聚体、三聚体和四聚体）上。在受感染细胞上，该表位以gp41的寡聚体、gp41的单体以及完整细胞生物素化后获得的包膜多蛋白gp160的一部分的形式存在，然后将细胞裂解并用各种单克隆抗体进行免疫沉淀。在受感染细胞的裂解物中，该表位以单体gp41和gp160两者的一部分的形式存在。这些研究表明，受感染的人类能够对gp41的融合形式作出反应，并且这里研究的抗gp41单克隆抗体识别由gp41的两个区域相互作用形成的构象表位，该构象表位形成一个α-螺旋束。这种表位存在于gp41的几种形式上，因为它存在于病毒粒子中、受感染细胞的表面以及受感染细胞内。
