He Yuxian, Honnen William J, Krachmarov Chavdar P, Burkhart Michael, Kayman Samuel C, Corvalan Jose, Pinter Abraham
Laboratory of Retroviral Biology, Public Health Research Institute, Newark, NJ 07103-3535, USA.
J Immunol. 2002 Jul 1;169(1):595-605. doi: 10.4049/jimmunol.169.1.595.
Despite considerable interest in the isolation of mAbs with potent neutralization activity against primary HIV-1 isolates, both for identifying useful targets for vaccine development and for the development of therapeutically useful reagents against HIV-1 infection, a relatively limited number of such reagents have been isolated to date. Human mAbs (hu-mAbs) are preferable to rodent mAbs for treatment of humans, but isolation of hu-mAbs from HIV-infected subjects by standard methods of EBV transformation of B cells or phage display of Ig libraries is inefficient and limited by the inability to control or define the original immunogen. An alternative approach for the isolation of hu-mAbs has been provided by the development of transgenic mice that produce fully hu-mAbs. In this report, we show that immunizing the XenoMouse G2 strain with native recombinant gp120 derived from HIV(SF162) resulted in robust humoral Ab responses against gp120 and allowed the efficient isolation of hybridomas producing specific hu-mAbs directed against multiple regions and epitopes of gp120. hu-mAbs possessing strong neutralizing activity against the autologous HIV(SF162) strain were obtained. The epitopes recognized were located in three previously described neutralization domains, the V2-, V3- and CD4-binding domains, and in a novel neutralization domain, the highly variable C-terminal region of the V1 loop. This is the first report of neutralizing mAbs directed at targets in the V1 region. Furthermore, the V2 and V3 epitopes recognized by neutralizing hu-mAbs were distinct from those of previously described human and rodent mAbs and included an epitope requiring a full length V3 loop peptide for effective presentation. These results further our understanding of neutralization targets for primary, R5 HIV-1 viruses and demonstrate the utility of the XenoMouse system for identifying new and interesting epitopes on HIV-1.
尽管人们对分离具有针对原发性HIV-1分离株的有效中和活性的单克隆抗体（mAb）有着浓厚兴趣，这既有助于确定疫苗开发的有用靶点，也有助于开发针对HIV-1感染的治疗性有用试剂，但迄今为止，此类试剂的分离数量相对有限。对于人类治疗而言，人源单克隆抗体（hu-mAb）比啮齿动物单克隆抗体更具优势，但通过B细胞的EBV转化或Ig文库的噬菌体展示等标准方法从HIV感染受试者中分离hu-mAb效率低下，且受限于无法控制或确定原始免疫原。转基因小鼠产生完全人源单克隆抗体的技术发展为hu-mAb的分离提供了一种替代方法。在本报告中，我们表明用源自HIV（SF162）的天然重组gp120免疫XenoMouse G2品系，可引发针对gp120的强烈体液抗体反应，并能有效分离出产生针对gp120多个区域和表位的特异性hu-mAb的杂交瘤。获得了对同源HIV（SF162）毒株具有强中和活性的hu-mAb。所识别的表位位于三个先前描述的中和结构域，即V2、V3和CD4结合结构域，以及一个新的中和结构域，即V1环的高度可变C末端区域。这是关于针对V1区域靶点的中和单克隆抗体的首次报告。此外，中和性hu-mAb识别的V2和V3表位与先前描述的人源和啮齿动物单克隆抗体的表位不同，其中包括一个需要全长V3环肽才能有效呈递的表位。这些结果加深了我们对原发性R5 HIV-1病毒中和靶点的理解，并证明了XenoMouse系统在识别HIV-1上新的和有趣表位方面的实用性。
