Gorny Miroslaw K, Williams Constance, Volsky Barbara, Revesz Kathy, Cohen Sandra, Polonis Victoria R, Honnen William J, Kayman Samuel C, Krachmarov Chavdar, Pinter Abraham, Zolla-Pazner Susan
Department of Pathology, New York University School of Medicine, New York, NY 10016, USA.
J Virol. 2002 Sep;76(18):9035-45. doi: 10.1128/jvi.76.18.9035-9045.2002.
The epitopes of the V3 domain of the human immunodeficiency virus type 1 (HIV-1) gp120 glycoprotein have complex structures consisting of linear and conformational antigenic determinants. Anti-V3 antibodies (Abs) recognize both types of elements, but Abs which preferentially react to the conformational aspect of the epitopes may have more potent neutralizing activity against HIV-1, as recently suggested. To test this hypothesis, human anti-V3 monoclonal Abs (MAbs) were selected using a V3 fusion protein (V3-FP) which retains the conformation of the third variable region. The V3-FP consists of the V3(JR-CSF) sequence inserted into a truncated form of murine leukemia virus gp70. Six human MAbs which recognize epitopes at the crown of the V3 loop were selected with the V3-FP. They were found to react more strongly with molecules displaying conformationally intact V3 than with linear V3 peptides. In a virus capture assay, these MAbs showed cross-clade binding to native, intact virions of clades A, B, C, D, and F. No binding was found to isolates from subtype E. The neutralizing activity of MAbs against primary isolates was determined in three assays: the GHOST cell assay, a phytohemagglutinin-stimulated peripheral blood mononuclear cell assay, and a luciferase assay. While these new MAbs displayed various degrees of activity, the pattern of cross-clade neutralization of clades A, B, and F was most pronounced. The neutralization of clades C and D viruses was weak and sporadic, and neutralization of clade E by these MAbs was not detected. Analysis by linear regression showed a highly significant correlation (P < 0.0001) between the strength of binding of these anti-V3 MAbs to intact virions and the percent neutralization. These studies demonstrate that human MAbs to conformation-sensitive epitopes of V3 display cross-clade reactivity in both binding to native, intact virions and neutralization of primary isolates.
人类免疫缺陷病毒1型（HIV-1）糖蛋白gp120的V3结构域的表位具有复杂结构，由线性和构象抗原决定簇组成。抗V3抗体（Abs）可识别这两种类型的元件，但最近有研究表明，优先与表位构象方面发生反应的抗体可能对HIV-1具有更强的中和活性。为验证这一假设，使用保留第三可变区构象的V3融合蛋白（V3-FP）筛选人抗V3单克隆抗体（MAbs）。V3-FP由插入鼠白血病病毒gp70截短形式的V3（JR-CSF）序列组成。用V3-FP筛选出6种识别V3环顶部表位的人MAbs。发现它们与呈现构象完整V3的分子反应比与线性V3肽更强。在病毒捕获试验中，这些MAbs显示出对A、B、C、D和F亚型天然完整病毒体的跨分支结合。未发现与E亚型分离株的结合。通过三种试验测定MAbs对原代分离株的中和活性：GHOST细胞试验、植物血凝素刺激的外周血单个核细胞试验和荧光素酶试验。虽然这些新的MAbs表现出不同程度的活性，但A、B和F亚型的跨分支中和模式最为明显。对C和D亚型病毒的中和作用较弱且不连续未检测到这些MAbs对E亚型的中和作用。线性回归分析表明，这些抗V3 MAbs与完整病毒体的结合强度与中和百分比之间存在高度显著的相关性（P<0.0001）。这些研究表明，针对V3构象敏感表位的人MAbs在与天然完整病毒体结合以及对原代分离株的中和方面均表现出跨分支反应性。
