Effects of partially dismantling the CD4 binding site glycan fence of HIV-1 Envelope glycoprotein trimers on neutralizing antibody induction

Crooks, Ema T.; Osawa, Keiko; Tong, Tommy; Grimley, Samantha L.; Dai, Yang; Whalen, Robert G.; Kulp, Daniel W.; Menis, Sergey; Schief, William R.; Binley, James Μ.

doi:10.1016/j.virol.2017.02.024

Cited by 33 publications

(46 citation statements)

References 89 publications

(234 reference statements)

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“…In some cases, the stimulation of germline reverted BCRs in vitro and in vivo was observed [ 60 , 61 ]; however, with limited autologous neutralization [ 59 ]. Two recent studies performed in parallel to ours used similar glycan-deleted immunogens [ 35 , 36 ] in outbred animals, but without the boosting regimens we described here. Crooks et al used JRFL Env based trimer VLPs both possessing (wt) and lacking the N-glycan at N362.…”

Section: Discussionmentioning

confidence: 99%

“…Crooks et al used JRFL Env based trimer VLPs both possessing (wt) and lacking the N-glycan at N362. They detected some autologous neutralization and mapping to CD4bs-proximal N-glycans [ 36 ], but with small numbers of animals per group it was not possible to determine statistical difference in the responses against wt or N362 glycan-deleted JRFL virus [ 36 , 62 ]. Zhou et al analyzed four well-ordered SOSIP trimers possessing targeted N-glycan deletions at the CD4bs including those derived from 16055-based chimeric trimer.…”

Section: Discussionmentioning

confidence: 99%

“…Here, guided by CD4bs antibodies and Env structures [ 2 , 32 , 33 ], we selectively deleted potential N-linked glycans (PNGS) proximal to the CD4bs on the well-ordered soluble clade C 16055 NFL TD CC trimers because of their high degree of stability and homogeneity [ 33 , 34 ]. Our goal was to enhance in vivo engagement by naïve B cells specific for this conserved neutralizing determinant regardless of the genetic properties of their B cell receptors (BCRs), similar in concept to two recent studies performed in parallel [ 35 , 36 ]. We generated a series of N-glycan-deleted variant trimers that maintained native-like trimer conformation without significant loss in stability.…”

Section: Introductionmentioning

confidence: 99%

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Targeted N-glycan deletion at the receptor-binding site retains HIV Env NFL trimer integrity and accelerates the elicited antibody response

et al. 2017

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Extensive shielding by N-glycans on the surface of the HIV envelope glycoproteins (Env) restricts B cell recognition of conserved neutralizing determinants. Elicitation of broadly neutralizing antibodies (bNAbs) in selected HIV-infected individuals reveals that Abs capable of penetrating the glycan shield can be generated by the B cell repertoire. Accordingly, we sought to determine if targeted N-glycan deletion might alter antibody responses to Env. We focused on the conserved CD4 binding site (CD4bs) since this is a known neutralizing determinant that is devoid of glycosylation to allow CD4 receptor engagement, but is ringed by surrounding N-glycans. We selectively deleted potential N-glycan sites (PNGS) proximal to the CD4bs on well-ordered clade C 16055 native flexibly linked (NFL) trimers to potentially increase recognition by naïve B cells in vivo. We generated glycan-deleted trimer variants that maintained native-like conformation and stability. Using a panel of CD4bs-directed bNAbs, we demonstrated improved accessibility of the CD4bs on the N-glycan-deleted trimer variants. We showed that pseudoviruses lacking these Env PNGSs were more sensitive to neutralization by CD4bs-specific bNAbs but remained resistant to non-neutralizing mAbs. We performed rabbit immunogenicity experiments using two approaches comparing glycan-deleted to fully glycosylated NFL trimers. The first was to delete 4 PNGS sites and then boost with fully glycosylated Env; the second was to delete 4 sites and gradually re-introduce these N-glycans in subsequent boosts. We demonstrated that the 16055 PNGS-deleted trimers more rapidly elicited serum antibodies that more potently neutralized the CD4bs-proximal-PNGS-deleted viruses in a statistically significant manner and strongly trended towards increased neutralization of fully glycosylated autologous virus. This approach elicited serum IgG capable of cross-neutralizing selected tier 2 viruses lacking N-glycans at residue N276 (natural or engineered), indicating that PNGS deletion of well-ordered trimers is a promising strategy to prime B cell responses to this conserved neutralizing determinant.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Targeted N-glycan deletion at the receptor-binding site retains HIV Env NFL trimer integrity and accelerates the elicited antibody response

et al. 2017

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“…The largest-effect mutations for both antibodies introduced a serine or threonine in place of the asparagine at site 197. The N197 glycan is part of a glycan fence that shields the CD4bs (Crooks et al, 2017). N197S and N197T (N197S/T) both eliminate this N197 glycan and introduce a new potential N-linked glycosylation motif (PNG) at N195.…”

Section: Escape From Cd4bs Bnabs Reveals Distinct Interprotomer Dynammentioning

confidence: 99%

An Antigenic Atlas of HIV-1 Escape from Broadly Neutralizing Antibodies Distinguishes Functional and Structural Epitopes

Dingens

Arenz²,

Weight³

et al. 2019

Immunity

115

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“…The largest-effect mutations for both antibodies introduced a serine or threonine in place of the asparagine at site 197. The N197 glycan is part of a glycan fence that shields the CD4bs (Crooks et al, 2017). N197S/T both eliminate this N197 glycan and introduce a new potential N-linked glycosylation motif (PNG) at N195.…”

Section: Figure 4 | Escape From Cd4bs Bnabs Abmentioning

confidence: 99%

An antigenic atlas of HIV-1 escape from broadly neutralizing antibodies

Dingens

Arenz²,

Weight³

et al. 2018

Preprint

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Anti-HIV broadly neutralizing antibodies (bnAbs) have revealed vaccine targets on the virus's Env protein and are themselves promising immunotherapeutics. The efficacy of bnAb-based therapies and vaccines depends in part on how readily the virus can escape neutralization. While structural studies can define contacts between bnAbs and Env, only functional studies can define mutations that confer escape. Here we map how all single amino-acid mutations to Env affect neutralization of HIV by nine bnAbs targeting five epitopes. For most bnAbs, mutations at only a small fraction of structurally defined contact sites mediated escape, and most escape occurred at sites that are near but do not directly contact the antibody. The mutations selected by two pooled bnAbs were similar to those expected from the combination of the bnAbs' independent action. Overall, our mutation-level antigenic atlas provides a comprehensive dataset for understanding viral immune escape and refining therapies and vaccines.

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Effects of partially dismantling the CD4 binding site glycan fence of HIV-1 Envelope glycoprotein trimers on neutralizing antibody induction

Cited by 33 publications

References 89 publications

Targeted N-glycan deletion at the receptor-binding site retains HIV Env NFL trimer integrity and accelerates the elicited antibody response

Targeted N-glycan deletion at the receptor-binding site retains HIV Env NFL trimer integrity and accelerates the elicited antibody response

An Antigenic Atlas of HIV-1 Escape from Broadly Neutralizing Antibodies Distinguishes Functional and Structural Epitopes

An antigenic atlas of HIV-1 escape from broadly neutralizing antibodies

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