Sun Lujia, Chen Bo, Liu Xianbo, Zhu Yun, Zhang Guangxu, Liang Xiaoxing, Xing Lixiao, Xu Wei, Jiang Shibo, Wang Xinling
Shanghai Institute of Infectious Disease and Biosecurity, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Frontiers Science Center of Pathogenic Microbes and Infection, Fudan University, Shanghai, China.
Chengdu NBbiolab. CO., LTD, SME Incubation Park, 319 Qingpi Avenue, Chengdu, China.
Curr Res Microb Sci. 2024 Jul 22;7:100263. doi: 10.1016/j.crmicr.2024.100263. eCollection 2024.
The highly conserved hydrophobic pocket region of HIV-1 gp41 NHR triple-stranded coiled coil is crucial for the binding of CHR to NHR to form a six-helix bundle (6-HB). This pocket is only exposed instantaneously during fusion, making it an ideal target for antibody drug design. However, IgG molecule is too big to enter the pocket during the fusion process. Therefore, to overcome the steric hindrance and kinetic obstacles caused by the formation of gp41 pre-hairpin fusion intermediate, we obtained nanobodies (Nbs) targeting NHR by immunizing alpaca with an NHR-trimer mimic. Specifically, we identified a Nb, Nb-172, that exhibited potent and broadly neutralizing activity against HIV-1 pseudoviruses, HIV-1 primary isolates, and T20-resistant HIV-1 strains. In addition, the combinatorial use of mD1.22 and Nb-172 exhibited synergism in inhibiting HIV-1 infection inactivating cell-free virions. Nb-172 can competitively bind to the hydrophobic pocket of gp41 NHR to inhibit 6-HB formation. These findings suggest that Nb-172 merits further investigation as a potential therapeutic for HIV-1 infection.
HIV-1 gp41 NHR三链卷曲螺旋高度保守的疏水口袋区域对于CHR与NHR结合形成六螺旋束（6-HB）至关重要。该口袋仅在融合过程中瞬间暴露，使其成为抗体药物设计的理想靶点。然而，IgG分子太大，在融合过程中无法进入该口袋。因此，为了克服由gp41前发夹融合中间体形成所造成的空间位阻和动力学障碍，我们用一种NHR三聚体模拟物免疫羊驼，获得了靶向NHR的纳米抗体（Nbs）。具体而言，我们鉴定出一种纳米抗体Nb-172，它对HIV-1假病毒、HIV-1原代分离株和T20耐药HIV-1毒株表现出强效且广泛的中和活性。此外，mD1.22和Nb-172的联合使用在使游离病毒失活从而抑制HIV-1感染方面表现出协同作用。Nb-172可竞争性结合gp41 NHR的疏水口袋以抑制6-HB的形成。这些发现表明，Nb-172作为一种潜在的HIV-1感染治疗药物值得进一步研究。
