Interdomain Stabilization Impairs CD4 Binding and Improves Immunogenicity of the HIV-1 Envelope Trimer

Zhang, Peng; Gorman, Jason; Geng, Hui; Liu, Qingbo; Yin, Lu; Tsybovsky, Yaroslav; Go, Eden P.; Dey, Barna; Andine, Tsion; Kwon, Alice; Patel, Mit; Gururani, Deepali; Uddin, Ferzan; Guzzo, Christina; Cimbro, Raffaello; Miao, Houxun; McKee, Krisha; Chuang, Gwo-Yu; Martin, Loı̈c; Sironi, Francesca; Malnati, Mauro S.; Desaire, Heather; Berger, Edward A.; Mascola, John R.; Dolan, Michael; Kwong, Peter D.; Lusso, Paolo

doi:10.1016/j.chom.2018.05.002

Cited by 45 publications

(58 citation statements)

References 57 publications

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“…These observations open the door to an 'epitope maskingbased design' strategy in which strain-specific or nonneutralizing epitopes are artificially covered to redirect the responses to other, potentially cross-neutralizing, epitopes [105,106]. Several studies have successfully used stabilizing mutations (reviewed in [84]), interdomain-locking mutations [107] and glycan shielding to decrease the immunogenicity of unwanted non-neutralizing epitopes without compromising the desired Ab responses [73, [106][107][108][109]. B cell immunology suggests that decreasing the immunogenicity of undesired epitopes should increase the competitive advantage of desired lower affinity bNAb epitopes [110].…”

Section: Epitope Maskingmentioning

confidence: 99%

Strategies for inducing effective neutralizing antibody responses against HIV-1

Moral-Sánchez

Sliepen

2019

Expert Review of Vaccines

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Introduction: Despite intensive research efforts, there is still no effective prophylactic vaccine available against HIV-1. Currently, substantial efforts are devoted to the development of vaccines aimed at inducing broadly neutralizing antibodies (bNAbs), which are capable of neutralizing most HIV-1 strains. All bNAbs target the HIV-1 envelope glycoprotein (Env), but Env immunizations usually only induce neutralizing antibodies (NAbs) against the sequence-matched virus and not against other strains. Areas covered: We describe the different strategies that have been explored to improve the breadth and potency of anti-HIV-1 NAb responses. The discussed strategies include the application of engineered Env immunogens, optimization of (bNAb) epitopes, different cocktail and sequential vaccination strategies, nanoparticles and nucleic acid-based vaccines. Expert opinion: A combination of the strategies described in this review and future approaches are probably needed to develop an effective HIV-1 vaccine that can induce broad, potent and long-lasting NAb responses.

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Section: Epitope Maskingmentioning

confidence: 99%

Strategies for inducing effective neutralizing antibody responses against HIV-1

Moral-Sánchez

Sliepen

2019

Expert Review of Vaccines

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“…10,13,17 Comparison of the F14 and Vt8 designs with previous stabilization strategies via the vector-based analysis (Figure 5D and E) revealed that most stabilized SOSIP structures, with the exception of those bound to fusion peptide-directed antibodies and the RC1 structures, resided in two dominant closed state clusters (Figure 5E; Supplementary Table 5). Interestingly, unlike previous stabilization strategies that either reduce or prevent CD4 binding 12,13,17,44 , the F14/Vt8 trimer retained interaction with CD4 while still preventing CD4-induced exposure of open state epitopes. Together, the findings presented here indicated close coupling of sCD4 induced internal rearrangements in gp120 and the N-terminal portion of the gp41 three-helix bundle.…”

Section: Discussionmentioning

confidence: 76%

“…Centroids for the vectors in the analysis included a K46-K490 Cα centroid, W571 and W596 c-αs, c-αs of gp120 excluding variable loops the V1/V1 region residues, and the N- and C-termni, and a V1/V2+V3 c-α centroid Vectors between these reference positions were generated and included a projection of the W596 to K46-K490 centroid vector on to the W596 to W571 vector. Angles, distances, and dihedrals between these vectors were then compiled for a set of available crystal and cryo-EM structures with PDB IDs 4TVP 71 , 4ZMJ 25 , 5ACO 72 , 5CEZ 37 , 5CJX 73 , 5D9Q 74 , 5FYJ 75 , 5FYK 75 , 5FYL 75 , 5T3X 76 , 5T3Z 76 , 5U7M 33 , 5U7O 33 , 5UTF 13 , 5V7J 77 , 5V8L 78 , 5V8M 78 , 6CDE 38 , 6CDI 38 , 6CH7 79 , 6CH8 79 , 6CUE 80 , 6CUF 81 , and 6DE7 12 , 5THR 26 , 5VN3 27 , 5VN8 73 , 6CM3 31 , 6EDU 31 , 5FUU 82 , 6DCQ 46 , 6MAR 83 , 5U1F 55 , 5C7K 84 , 5I8H 85 , 5UM8 86 , 5UTY 13 , 5VIY 87 , 5VJ6 87 , 5WDU 14 , 6B0N 88 , 6CCB 89 , 6CE0 11 , 6CH9 79 , 6CHB 79 , 6CK9 90 , 6DCQ 46 , 6DID 91 , 6E5P 92 , 6IEQ 93 , 6MCO 94 , 6MDT 94 , 6MN7 95 , 6MPG 96 , 6MPH 96 , 6MTJ 97 , 6MTN 97 , 6MU6 97 , 6MU7 97 , 6MU8 97 , 6MUF 97 , 6MUG 97 , 6N1V 96 , 6N1W 96 , 6NC2 98 , 6NC3 98 , 6NF2 96 , 6NIJ 47 , 6NM6 99 , 6NNF 99 , 6NNJ 99 , 6OHY 100 , 6OKP 101 , 6OLP 47 , 6ORN 39 , 6ORO 39 , 6OR...…”

Section: Methodsmentioning

confidence: 99%

Disruption of the HIV-1 Envelope allosteric network blocks CD4-induced rearrangements

Henderson

Zhou

et al. 2019

Preprint

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30The trimeric HIV-1 Envelope protein (Env) mediates viral-host cell fusion via a network of 31 conformational transitions, with allosteric elements in each protomer orchestrating host 32 receptor-induced exposure of the co-receptor binding site and fusion elements. To 33 understand the molecular details of this allostery, we introduced Env mutations aimed to 34 prevent CD4-induced rearrangements in the HIV-1 BG505 Env trimer. Binding analysis 35 performed on the soluble ectodomain BG505 SOSIP Env trimers, cell-surface expressed 36 BG505 full-length trimers and single-molecule Förster Resonance Energy Transfer 37 (smFRET) performed on the full-length virion-bound Env confirmed that these mutations 38 prevented CD4-induced transitions of the HIV-1 Env. Structural analysis by single-39 particle cryo-electron microscopy performed on the BG505 SOSIP mutant Env proteins 40 revealed rearrangements in the gp120 topological layer contacts with gp41. Specifically, 41 a conserved tryptophan at position 571 (W571) was displaced from its typical pocket at 42 the interface of gp120 topological layers 1 and 2 by lysine 567, disrupting key gp120-43 gp41 contacts and rendering the Env insensitive to CD4 binding. Vector based analysis 44 of closed Env SOSIP structures revealed the newly designed trimers exhibited a 45 quaternary structure distinct from that typical of SOSIPs and residing near a cluster of 46 Env trimers bound to vaccine-induced fusion peptide-directed antibodies (vFP Mabs). 47These results reveal the critical function of W571 as a conformational switch in Env 48 allostery and receptor-mediated viral entry and provide insights on Env conformation that 49 are relevant for vaccine design.50 51 52 53 54Host cell entry of HIV-1 is accomplished by the envelope glycoprotein (Env) spike. HIV-1 55Env is a trimer of heterodimers comprised of gp120 and gp41 protomers, and exists in a 56 metastable conformation capable of transitioning from a prefusion closed configuration to a 57 fusion-competent open state upon triggering by CD4. 1,2 The C-terminal gp41 domain contains a 58 single transmembrane helix and the membrane fusion elements of the trimer. 3-5 The gp12059 segment binds the primary receptor CD4, triggering conformational changes leading to the 60 binding of co-receptor CCR5/CXCR4 that causes global rearrangements in the trimer structure 61 leading to viral and cell membrane fusion and gp120 shedding. 6-8 While many studies have 62 sought to understand the nature of the communication between the CD4 binding site, the 63 coreceptor binding site and the fusogenic elements of the HIV-1 Env, a complete understanding 64 of the allosteric mechanism and metastability in HIV-1 Env remains lacking. 65The design of a soluble, stabilized ectodomain Env (SOSIP), containing an engineered 66 gp120 to gp41 disulfide (SOS) and an HR1 helix breaking I to P mutation, has revealed 67 structural details regarding broadly neutralizing antibody (bnAb) epitopes and as an immunogen 68 has induced autologous neutralizing antibodies. 2,9 The...

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“…In addition to the structural studies discussed above, both the SOS and DS changes are being used in soluble Env trimers for immunization studies (51,54,55,(61)(62)(63)(64)(65)(66)(67)(68)(69)(70)(71). However, it has been reported that changes in hydrophobic gp41 residues near the viral membrane can disrupt a state 1 HIV-1 Env conformation (13,(72)(73)(74)(75)(76)(77), raising the possibility that membrane interactions can influence the conformation of the HIV-1 Env ectodomain.…”

mentioning

confidence: 99%

Effects of the SOS (A501C/T605C) and DS (I201C/A433C) Disulfide Bonds on HIV-1 Membrane Envelope Glycoprotein Conformation and Function

Nguyen

Alsahafi

Finzi

et al. 2019

J Virol

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Most broadly neutralizing antibodies and many entry inhibitors target the pretriggered (state 1) conformation of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env). Here we examine two previously reported Env mutants designed to be stabilized in this conformation by the introduction of artificial disulfide bonds: A501C/T605C (called SOS) and I201C/A433C (called DS). SOS Env supported virus entry and cell-cell fusion only after exposure to a reducing agent, dithiothreitol (DTT). Deletion of the Env cytoplasmic tail improved the efficiency with which the SOS Env supported virus infection in a reducing environment. The antigenicity of the SOS Env was similar to that of the unmodified Env, except for greater sensitivity to some state 1-preferring ligands. In contrast, viruses with the DS Env were not infectious, even after DTT treatment. The proteolytic maturation of the DS Env on both cell surfaces and virions was severely compromised compared with that of the unmodified Env. The DS Env exhibited detectable cell-fusing activity when DTT was present. However, the profiles of cell-surface Env recognition and cell-cell fusion inhibition by antibodies differed for the DS Env and the unmodified Env. Thus, the DS Env appears to be stabilized in an off-pathway conformation that is nonfunctional on the virus. The SOS change exerted more subtle, context-dependent effects on Env conformation and function. IMPORTANCE The human immunodeficiency virus type 1 (HIV-1) envelope proteins (Envs) bind receptors on the host cell and change shape to allow the virus to enter the cell. Most virus-inhibiting antibodies and drugs recognize a particular shape of Env called state 1. Disulfide bonds formed by cysteine residues have been introduced into soluble forms of the flexible envelope proteins in an attempt to lock them into state 1 for use in vaccines and as research tools. We evaluated the effect of these cysteine substitutions on the ability of the membrane Env to support virus entry and on susceptibility to inhibition by antibodies and small molecules. We found that the conformation of the envelope proteins with the cysteine substitutions differed from that of the unmodified membrane envelope proteins. Awareness of these effects can assist efforts to create stable HIV-1 Env complexes that more closely resemble the state 1 conformation.

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Interdomain Stabilization Impairs CD4 Binding and Improves Immunogenicity of the HIV-1 Envelope Trimer

Cited by 45 publications

References 57 publications

Strategies for inducing effective neutralizing antibody responses against HIV-1

Strategies for inducing effective neutralizing antibody responses against HIV-1

Disruption of the HIV-1 Envelope allosteric network blocks CD4-induced rearrangements

Effects of the SOS (A501C/T605C) and DS (I201C/A433C) Disulfide Bonds on HIV-1 Membrane Envelope Glycoprotein Conformation and Function

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