Conformational antigenic heterogeneity as a cause of the persistent fraction in HIV-1 neutralization

Colin, Philippe; Ringe, Rajesh P.; Yasmeen, Anila; Ozorowski, Gabriel; Ketas, Thomas J.; Lee, Wen-Hsin; Ward, Andrew B.; Moore, John P.; Klasse, P J

doi:10.1186/s12977-023-00624-9

Cited by 6 publications

(15 citation statements)

References 110 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…GnT1-Env lacks complex glycans that impart glyco-heterogeneity, consistent with the diffuse gp160m, gp120 and gp41 bands of the parent. In contrast, the poorly expressed GnT1-gp160m, gp120 and gp41 bands were all sharp, consistent with greater homogeneity (S2B Fig,compare Mixing neuraminidase and galactosidase (NG) visibly increased gp160m, gp120 and gp41 mobility, which was clearer in lanes digested with endo H (S2B Fig, lanes [11][12][13][14]. Further mobility changes were not detected when acetylglucosamidase (NGA) and endo F3 (NGAF3) were added (S2B Fig, compare lanes 13-18), suggesting that steric constraints limit their activities.…”

Section: Resultssupporting

confidence: 54%

“…Thus, a bNAb may neutralize a fraction of virus with a relatively small clashing glycan, but not the fraction with a large clashing glycan [10,11]. This epigenetic virus "escape" results in a sub-saturating neutralization plateau [5,[10][11][12][13]. Because of these challenges, preclinical vaccine NAbs tend to vary in potency and saturation, usually with limited breadth [14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Impact of Glycan Depletion, Glycan Debranching and Increased Glycan Charge on HIV-1 Neutralization Sensitivity and Immunogenicity

D’Addabbo,

Tong,

Crooks

et al. 2024

Preprint

View full text Add to dashboard Cite

Modifying HIV-1’s envelope glycoprotein glycans can impact its neutralization sensitivity. The use of the knock out cell line GnT1-prevents the elaboration of complex-type glycans, and opens up the glycan shield, increasing bNAb vulnerability. Some bNAb precursors can bind to GnT1-trimers, supporting their use in vaccine priming. However, GnT1-trimers express poorly and exhibit very low infectious counts. Here, we describe two other potentially vaccine-relevant glycoengineered trimers, 1) To truncate complex glycans, we used of a cocktail of glycosidases, termed “NGAF3” (Neuraminidase, β-Galactosidase, N-Acetylglucosaminidase and endoglycosidaseF3). Like GnT1-trimers, NGAF3 reduced glycan clashes and increased bNAb potency while retaining a closed trimer conformation; 2) Modified by β-1,4-galactosyltransferase 1 (B4GalT1) and β-galactoside α-2,6 sialyltransferase 1 (ST6Gal1) during Env biosynthesis. Glycan mass spectrometry revealed that NGAF3 removed glycan heads of 3 of 7 positions on the trimer that are largely occupied by complex glycans. It also revealed a novel B4GalT1 activity to favor glycan precursor conversion to hybrid glycans rather than complex glycans. A comparison to monomeric gp120 revealed that B4GalT1’s new activity depends on tight glycan spacing. B4GalT1 affected more glycans than NGAF3 (6 out of 7 glycans), perhaps due to greater accessibilityduringEnv folding rather thanafterfolding. Surprisingly, the N611 glycan was unaffected by either modification. B4GalT1 and ST6Gal1 cooperatively increased the abundance of hybrid glycans and α-2,6 hypersialylated termini. This occurred largely by amplifying the abundance of a limited number of hybrid glycan structures that are also present on unmodified trimers. In rabbit vaccinations, B4GalT1+ST6GalT1-modified virus-like particles reduced the frequency and titers of serum NAbs that showed a modest preference for modified glycans. Conversely, chronically HIV-1-infected donor plasma neutralizing antibody titers were 1.7- to 10.8- fold higher against B4GalT1+ST6GalT1-modified pseudovirus. Overall, our data provide tools for heterologous prime, boost and polishing vaccine regimens using modified glycans.AUTHOR SUMMARYAn HIV-1 vaccine remains one of the most significant biomedical challenges today. Vaccines often work by triggering virus fighting antibodies to stave off infection. For HIV-1, this has been exceedingly difficult because the target, called the HIV-1 envelope glycoprotein (Env) is extremely variable and carries a thick sugar coat, protecting it from all but a few rare broadly reactive antibodies (termed bNAbs) that sometimes develop during natural HIV-1 infection. Given these challenges, it is reasonable to propose that any successful vaccine will need to be rationally designed to trigger the rare bNAbs. To meet this goal might require more 3 different vaccine components. First, a vaccine “prime” to trigger rare bNAb proliferation, followed by heterologous “boosts” and “polishing” immunogens to select for bNAbs. In this study, we evaluated two potential immunogens. In one approach, we used cocktails of enzymes to strip Env’s sugar coat, in the hope of reducing the barrier to stimulate bNAb precursors. In another, we used excess enzymes to build particular structures on Env’s coat. We checked how well these two Env variants were recognized by antibodies. We also checked in fine detail how the sugars were changed at the molecular level. Finally, we immunized rabbits. Our data enrich the number of strategies available to further explore the concept of priming, boosting and polishing vaccine shots.

show abstract

Section: Resultssupporting

confidence: 54%

Section: Introductionmentioning

confidence: 99%

Impact of Glycan Depletion, Glycan Debranching and Increased Glycan Charge on HIV-1 Neutralization Sensitivity and Immunogenicity

D’Addabbo,

Tong,

Crooks

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

“…Another potential mechanism for partial bNAb resistance can be posttranslational modifications on Env such as glycosylation heterogeneity or conformational heterogeneity in genetically identical virions. This can result in a fraction of clonal virions exhibiting resistance to bNAbs, and is often observed as incomplete neutralization curve plateaus or persistent fractions [6,24,25 ▪ ]. We have shown that combining bNAbs can overcome such heterogeneous resistant fractions of virus [6], suggesting that bNAbs are complementary also in the impact of posttranslational modifications underlying partial bNAb resistance.…”

Section: Complementarity Of Broadly Neutralizing Antibody Resistance ...mentioning

confidence: 94%

Divide and conquer: broadly neutralizing antibody combinations for improved HIV-1 viral coverage

Wagh

Seaman

2023

Current Opinion in HIV and AIDS

View full text Add to dashboard Cite

Purpose of reviewSuccessful HIV-1 prevention and therapy will require broad and potent coverage of within-host and global viral diversity. Broadly neutralizing antibody (bNAb) combination and multispecific therapeutics provide an opportunity to meet this challenge due to the complementary activity of individual antibody components. Here, we review the principles and applications of this concept. Recent findingsThe Antibody Mediated Prevention (AMP) trials have demonstrated the high bar for neutralization potency and breadth that bNAb-mediated prevention modalities will need to achieve to have a meaningful impact on the HIV-1 epidemic. Additional clinical studies have recently shown that an even higher bar may be required for therapeutic inhibition of the diverse within-host quasispecies present in viremic and aviremic people with HIV-1 (PWH). We discuss how the complementarity of bNAbs in terms of neutralization profiles, resistance mutations and coverage of within-host quasispecies may overcome these stringent requirements and lead to effective bNAb combination or multispecific antibody based prophylactic and therapeutic strategies.

show abstract

“…PFs and low slopes of the neutralization curves have been described for various isolates of HIV-1 and SHIV in combination with bNAbs directed to several epitope clusters located all over the Env trimer: at the trimer apex, the V3-base, the outer-domain mannose patch, the CD4-binding site (CD4-bs), the fusion peptide (FP) and interface between the outer (gp120) and transmembrane (gp41) subunits, and the membrane-proximate external region of gp41 [37][38][39][40][41][42][43][44][45][46][47][48][49]. PFs in neutralization by bNAbs directed to the trimer apex and interface-FP have been attributed to conformational flexibility, although such effects may be the atypical features of Env derived from particular isolates [37,41].…”

Section: Plos Pathogensmentioning

confidence: 99%

“…Glycosylation differences may be explanatory factors in all these cases, although other covalent modifications cannot be excluded; nor can non-covalent variations on the basis solely of these data (cf. [37]). Allosteric modulation of the antigenicity can arise through domino effects within the glycan shield through varied glycan bulk, charge, and occupancy.…”

Section: Plos Pathogensmentioning

confidence: 99%

Glycan heterogeneity as a cause of the persistent fraction in HIV-1 neutralization

Ringe,

Colin,

Ozorowski

et al. 2023

PLoS Pathog

Self Cite

View full text Add to dashboard Cite

Neutralizing antibodies (NAbs) to multiple epitopes on the HIV-1-envelope glycoprotein (Env) have been isolated from infected persons. The potency of NAbs is measured more often than the size of the persistent fraction of infectivity at maximum neutralization, which may also influence preventive efficacy of active or passive immunization and the therapeutic outcome of the latter. Many NAbs neutralize HIV-1 CZA97.012, a clone of a Clade-C isolate, to ~100%. But here NAb PGT151, directed to a fusion-peptide epitope, left a persistent fraction of 15%. NAb PGT145, ligating the Env-trimer apex, left no detectable persistent fraction. The divergence in persistent fractions was further analyzed by depletion of pseudoviral populations of the most PGT151- and PGT145-reactive virions. Thereby, neutralization by the non-depleting NAb increased, whereas neutralization by the depleting NAb decreased. Furthermore, depletion by PGT151 increased sensitivity to autologous neutralization by sera from rabbits immunized with soluble native-like CZA97.012 trimer: substantial persistent fractions were reduced. NAbs in these sera target epitopes comprising residue D411 at the V4-β19 transition in a defect of the glycan shield on CZA97.012 Env. NAb binding to affinity-fractionated soluble native-like CZA97.012 trimer differed commensurately with neutralization in analyses by ELISA and surface plasmon resonance. Glycan differences between PGT151- and PGT145-purified trimer fractions were then demonstrated by mass spectrometry, providing one explanation for the differential antigenicity. These differences were interpreted in relation to a new structure at 3.4-Å resolution of the soluble CZA97.012 trimer determined by cryo-electron microscopy. The trimer adopted a closed conformation, refuting apex opening as the cause of reduced PGT145 binding to the PGT151-purified form. The evidence suggests that differences in binding and neutralization after trimer purification or pseudovirus depletion with PGT145 or PGT151 are caused by variation in glycosylation, and that some glycan variants affect antigenicity through direct effects on antibody contacts, whereas others act allosterically.

show abstract

Conformational antigenic heterogeneity as a cause of the persistent fraction in HIV-1 neutralization

Cited by 6 publications

References 110 publications

Impact of Glycan Depletion, Glycan Debranching and Increased Glycan Charge on HIV-1 Neutralization Sensitivity and Immunogenicity

Impact of Glycan Depletion, Glycan Debranching and Increased Glycan Charge on HIV-1 Neutralization Sensitivity and Immunogenicity

Divide and conquer: broadly neutralizing antibody combinations for improved HIV-1 viral coverage

Glycan heterogeneity as a cause of the persistent fraction in HIV-1 neutralization

Contact Info

Product

Resources

About