Impact of amino acid substitutions in the V2 and C2 regions of human immunodeficiency virus type 1 CRF01_AE envelope glycoprotein gp120 on viral neutralization susceptibility to broadly neutralizing antibodies specific for the CD4 binding site

Abstract

BackgroundThe CD4 binding site (CD4bs) of envelope glycoprotein (Env) gp120 is a functionally conserved, important target of anti-human immunodeficiency virus type 1 (HIV-1) neutralizing antibodies. Two neutralizing human monoclonal antibodies, IgG1 b12 (b12) and VRC01, are broadly reactive neutralizing antibodies which recognize conformational epitopes that overlap the CD4bs of Env gp120; however, many CRF01_AE viruses are resistant to neutralization mediated by these antibodies. We examined the mechanism underlying the b12 resistance of the viruses using CRF01_AE Env (AE-Env)-recombinant viruses in this study.ResultsOur results showed that an amino acid substitution at position 185 in the V2 region of gp120 played a crucial role in regulating the b12 susceptibility of AE-Env-recombinant viruses by cooperating with 2 previously reported potential N-linked glycosylation (PNLG) sites at positions 186 (N186) and 197 (N197) in the V2 and C2 regions of Env gp120. The amino acid residue at position 185 and 2 PNLG sites were responsible for the b12 resistance of 21 of 23 (>91%) AE-Env clones tested. Namely, the introduction of aspartic acid at position 185 (D185) conferred b12 susceptibility of 12 resistant AE-Env clones in the absence of N186 and/or N197, while the introduction of glycine at position 185 (G185) reduced the b12 susceptibility of 9 susceptible AE-Env clones in the absence of N186 and/or N197. In addition, these amino acid mutations altered the VRC01 susceptibility of many AE-Env clones.ConclusionsWe propose that the V2 and C2 regions of AE-Env gp120 contain the major determinants of viral resistance to CD4bs antibodies. CRF01_AE is a major circulating recombinant form of HIV-1 prevalent in Southeast Asia. Our data may provide important information to understand the molecular mechanism regulating the neutralization susceptibility of CRF01_AE viruses to CD4bs antibodies.

Prediction of VRC01 neutralization sensitivity by HIV-1 gp160 sequence features

“…Excellent research has been done to understand HIV-1 Env genotypic/AA features that affect VRC01 resistance [2, 9, 41–44]. Our approach complements this work by applying state-of-the-art machine learning and methodology for unbiased, nonparametric statistical inference (our area of expertise) − a contribution not yet provided in previous computational approaches to define AA sequence signatures for various bnAbs [7, 45–49] − and then interpreting the results in comparison with those from literature.…”

To prescreen or not to prescreen for broadly neutralizing antibody sensitivity in HIV cure-related trials

“… 10 , 37 This technique is more efficient and cost-effective in comparison to assay-based methods and has been used by numerous HIV-1 bNAb studies. 10 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 Of note, Gaebler et al have found that, in comparison to neutralization assays, genotypic prediction to identify resistance was inadequate, suggesting further room for improvement. 8 …”

HIV-1 subtype CRF01_AE and B differ in utilization of low levels of CCR5, Maraviroc susceptibility and potential N-glycosylation sites

“…In another study, Prevost et al showed that AE subtype expose the ADCC epitopes on the Env glycoprotein as a consequence of the H375 substitution (Prevost et al, 2017). Furthermore, the insensitivity of AE subtype to broadly neutralizing antibodies that bind the CD4 interacting region on Env has been well documented (Chen et al, 2016; Utachee et al, 2014). While these studies provide evidence that Envs from AE subtype engage CD4 differently and have specific changes within the CD4 binding region of the Env; our study shows that AE subtype also differs in CCR5 engagement compared to subtype B Envs from the same region.…”