Hadlock K G, Lanford R E, Perkins S, Rowe J, Yang Q, Levy S, Pileri P, Abrignani S, Foung S K
Departments of Pathology, Stanford University, Stanford, CA 94304, USA.
J Virol. 2000 Nov;74(22):10407-16. doi: 10.1128/jvi.74.22.10407-10416.2000.
The intrinsic variability of hepatitis C virus (HCV) envelope proteins E1 and E2 complicates the identification of protective antibodies. In an attempt to identify antibodies to E2 proteins from divergent HCV isolates, we produced HCV E2 recombinant proteins from individuals infected with HCV genotypes 1a, 1b, 2a, and 2b. These proteins were then used to characterize 10 human monoclonal antibodies (HMAbs) produced from peripheral B cells isolated from an individual infected with HCV genotype 1b. Nine of the antibodies recognize conformational epitopes within HCV E2. Six HMAbs identify epitopes shared among HCV genotypes 1a, 1b, 2a, and 2b. Six, including five broadly reactive HMAbs, could inhibit binding of HCV E2 of genotypes 1a, 1b, 2a, and 2b to human CD81 when E2 and the antibody were simultaneously exposed to CD81. Surprisingly, all of the antibodies that inhibited the binding of E2 to CD81 retained the ability to recognize preformed CD81-E2 complexes generated with some of the same recombinant E2 proteins. Two antibodies that did not recognize preformed complexes of HCV 1a E2 and CD81 also inhibited binding of HCV 1a virions to CD81. Thus, HCV-infected individuals can produce antibodies that recognize conserved conformational epitopes and inhibit the binding of HCV to CD81. The inhibition is mediated via antibody binding to epitopes outside of the CD81 binding site in E2, possibly by preventing conformational changes in E2 that are required for CD81 binding.
丙型肝炎病毒（HCV）包膜蛋白E1和E2的内在变异性使得保护性抗体的鉴定变得复杂。为了鉴定来自不同HCV分离株的E2蛋白抗体，我们从感染HCV 1a、1b、2a和2b基因型的个体中制备了HCV E2重组蛋白。然后用这些蛋白来表征从感染HCV 1b基因型个体分离的外周血B细胞产生的10种人单克隆抗体（HMAbs）。其中9种抗体识别HCV E2内的构象表位。6种HMAbs鉴定出HCV 1a、1b、2a和2b基因型共有的表位。当E2和抗体同时与CD81接触时，6种抗体（包括5种具有广泛反应性的HMAbs）可抑制HCV 1a、1b、2a和2b基因型的E2与人CD81的结合。令人惊讶的是，所有抑制E2与CD81结合的抗体都保留了识别由某些相同重组E2蛋白产生的预先形成的CD81-E2复合物的能力。两种不识别HCV 1a E2和CD81预先形成复合物的抗体也抑制HCV 1a病毒颗粒与CD81的结合。因此，HCV感染个体可产生识别保守构象表位并抑制HCV与CD81结合的抗体。这种抑制作用是通过抗体与E2中CD81结合位点之外的表位结合介导的，可能是通过阻止CD81结合所需的E2构象变化来实现的。
