Polzer Svenja, Dittmar Matthias T, Schmitz Herbert, Schreiber Michael
Bernhard Nocht Institute for Tropical Medicine, 20359, Hamburg, Germany.
Virology. 2002 Dec 5;304(1):70-80. doi: 10.1006/viro.2002.1760.
We have studied infectivity and neutralization of X4, R5, and R5X4 tropic HIV-1 mutants, which are lacking N-linked glycosylation sites for glycans g13, g14, g15, and g17 in the V3 loop region of gp120. X4-tropic NL4-3 mutants lacking combinations of g14/15 or g15/17 showed markedly higher infectivity in CXCR4-specific infection. The role of g15 in CCR5-specific infection was investigated using viruses with high (NL-918, R5-monotropic), medium (NL-991, R5-monotropic), and low (NL-952, R5X4-dualtropic) CCR5-specific infectivity. For NL-991, a reduction of infectivity on GHOST-CCR5 cells was observed for a mutant lacking g15. For NL-952 mutants all lacking g15, a complete loss of CCR5-specificity was observed and NL-952 was shifted from R5X4 to X4 tropism. For all mutants of NL4-3, NL-991, and NL-952, where the lack of g15 markedly influenced infectivity or coreceptor usage, neutralization was enhanced. In contrast, NL-918 mutants with or without g15 showed no difference in neutralization and no difference in GHOST-CCR5 infection rates. Thus, for viruses with a low or medium CCR5-specificity the role of g15 for changing CCR5-usage and sensitivity to neutralization was more significant than for viruses with high infection rates on GHOST-CCR5 cells. Our data demonstrate that V3 glycans play an important role in the usage of CXCR4 and CCR5. The lack of g15 was relevant for a more efficient use of CXCR4, whereas interaction with CCR5 was facilitated in the presence of g15. This study also demonstrates that glycan g15 is involved in blocking of neutralizing antibodies and shifting HIV tropism from R5X4 to X4.
我们研究了X4、R5和R5X4嗜性的HIV-1突变体的感染性和中和作用，这些突变体在gp120的V3环区域缺乏与聚糖g13、g14、g15和g17相连的N-糖基化位点。缺乏g14/15或g15/17组合的X4嗜性NL4-3突变体在CXCR4特异性感染中表现出明显更高的感染性。使用具有高（NL-918，R5单嗜性）、中（NL-991，R5单嗜性）和低（NL-952，R5X4双嗜性）CCR5特异性感染性的病毒研究了g15在CCR5特异性感染中的作用。对于NL-991，观察到缺乏g15的突变体对GHOST-CCR5细胞的感染性降低。对于所有都缺乏g15的NL-952突变体，观察到CCR5特异性完全丧失，并且NL-952从R5X4嗜性转变为X4嗜性。对于NL4-3、NL-991和NL-952的所有突变体，其中缺乏g15显著影响感染性或共受体使用，中和作用增强。相比之下，有或没有g15的NL-918突变体在中和作用上没有差异，在GHOST-CCR5感染率上也没有差异。因此，对于具有低或中等CCR5特异性的病毒，g15在改变CCR5使用和中和敏感性方面的作用比在GHOST-CCR5细胞上具有高感染率的病毒更显著。我们的数据表明，V3聚糖在CXCR4和CCR5的使用中起重要作用。缺乏g15与更有效地使用CXCR4相关，而在存在g15的情况下促进了与CCR5的相互作用。这项研究还表明，聚糖g15参与中和抗体的阻断以及将HIV嗜性从R5X4转变为X4。
