Wang Wenbo, Zirkle Brett, Nie Jianhui, Ma Jian, Gao Kai, Chen Xiaojiang S, Huang Weijing, Kong Wei, Wang Youchun
*College of Life Science, Jilin University, Changchun, China; †Key Laboratory of the Ministry of Health for Research on Quality and Standardization of Biotech Products, Division of Monoclonal Antibody, National Institutes for Food and Drug Control (NIFDC), Beijing, China; ‡Department of Molecular and Computational Biology/Chemistry Department/Norris Cancer Center, University of Southern California, Los Angeles, CA; and §Key Laboratory of the Ministry of Health for Research on Quality and Standardization of Biotech Products, Division of HIV/AIDS and Sex-Transmitted Virus Vaccines, National Institutes for Food and Drug Control (NIFDC), Beijing, China.
J Acquir Immune Defic Syndr. 2015 Jul 1;69(3):270-7. doi: 10.1097/QAI.0000000000000595.
HIV-1 gp120/gp41 is heavily modified by n-linked carbohydrates that play important roles either in correct folding or in shielding vulnerable viral protein surfaces from antibody recognition.
In our previous work, 25 potential N-linked glycosylation sites (PNGS) of a CRF07_BC isolate of HIV-1 were individually mutated, and the resulting effects on infectivity and antibody-mediated neutralization were evaluated. To further understand the functional role of these PNGS, we generated double and multiple mutants from selected individual PNGS mutants. The effects were then evaluated by examining infectivity and sensitivity to antibody-mediated neutralization by neutralizing monoclonal antibodies (nMAbs) and serum antibodies from HIV-1 positive donors.
Infectivity results showed that, among the 12 combined PNGS mutants, only 197M.1 (N197D/N301Q) lost infectivity completely, whereas all others (except for 197M.6) showed reduced viral infectivity. In terms of neutralization sensitivity to known nMAbs, we found that adding N463Q mutation to all the gp120 mutants containing N197D significantly increased neutralization sensitivity to VRC01 and VRC03, suggesting N197 and N463 have a strong synergistic effect in regulating the neutralizing sensitivity of HIV-1 to the anti-CD4bs nMAbs VRC01/VRC03. Structural analysis based on the available structures of gp120 alone and in complex with CD4 and various nMAbs elucidates a molecular rationale for this experimental observation.
The data indicate that N463 plays an important role in regulating the CD4bs MAbs VRC01/VRC03 sensitivity in the genetic background of N197D mutation of gp120, which should provide valuable information for a better understanding of the interplay between HIV-1 and VRC01/03.
HIV-1 gp120/gp41被N-连接碳水化合物大量修饰，这些碳水化合物在正确折叠或保护易受攻击的病毒蛋白表面不被抗体识别方面发挥重要作用。
在我们之前的工作中，对一株HIV-1 CRF07_BC分离株的25个潜在N-连接糖基化位点（PNGS）进行了单独突变，并评估了其对感染性和抗体介导中和作用的影响。为了进一步了解这些PNGS的功能作用，我们从选定的单个PNGS突变体中构建了双突变体和多突变体。然后通过检测感染性以及对来自HIV-1阳性供体的中和单克隆抗体（nMAbs）和血清抗体介导的中和作用的敏感性来评估其效果。
感染性结果显示，在12个组合的PNGS突变体中，只有197M.1（N197D/N301Q）完全丧失感染性，而其他所有突变体（除197M.6外）的病毒感染性均降低。在对已知nMAbs的中和敏感性方面，我们发现，在所有含有N197D的gp120突变体中添加N463Q突变显著增加了对VRC01和VRC03的中和敏感性，表明N197和N463在调节HIV-1对抗CD4bs nMAbs VRC01/VRC03的中和敏感性方面具有很强的协同作用。基于单独的gp120以及与CD4和各种nMAbs复合物的现有结构进行的结构分析阐明了这一实验观察结果的分子原理。
数据表明，在gp120的N197D突变的遗传背景下，N463在调节CD4bs单克隆抗体VRC01/VRC03敏感性方面发挥重要作用，这应为更好地理解HIV-1与VRC01/03之间的相互作用提供有价值的信息。
