Browse
Submit Data
Databases
API
Help

Dataset Information

28 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Bispecific Anti-HIV Immunoadhesins That Bind Gp120 and Gp41 Have Broad and Potent HIV-Neutralizing Activity.

ABSTRACT: We have constructed bispecific immunoglobulin-like immunoadhesins that bind to both the HIV-envelope glycoproteins: gp120 and gp41. These immunoadhesins have N terminal domains of human CD4 engrafted onto the N-terminus of the heavy chain of human anti-gp41 mAb 7B2. Binding of these constructs to recombinant Env and their antiviral activities were compared to that of the parental mAbs and CD4, as well as to control mAbs. The CD4/7B2 constructs bind to both gp41 and gp140, as well as to native Env expressed on the surface of infected cells. These constructs deliver cytotoxic immunoconjugates to HIV-infected cells, but not as well as a mixture of 7B2 and sCD4, and opsonize for antibody-mediated phagocytosis. Most surprisingly, given that 7B2 neutralizes weakly, if at all, is that the chimeric CD4/7B2 immunoadhesins exhibit broad and potent neutralization of HIV, comparable to that of well-known neutralizing mAbs. These data add to the growing evidence that enhanced neutralizing activity can be obtained with bifunctional mAbs/immunoadhesins. The enhanced neutralization activity of the CD4/7B2 chimeras may result from cross-linking of the two Env subunits with subsequent inhibition of the pre-fusion conformational events that are necessary for entry.

SUBMITTER: Pincus SH

PROVIDER: S-EPMC8310024 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Super Potent Bispecific Llama VHH Antibodies Neutralize HIV via a Combination of gp41 and gp120 Epitopes.

Project description:Broad and potent neutralizing llama single domain antibodies (VHH) against HIV-1 targeting the CD4 binding site (CD4bs) have previously been isolated upon llama immunization. Here we describe the epitopes of three additional VHH groups selected from phage libraries. The 2E7 group binds to a new linear epitope in the first heptad repeat of gp41 that is only exposed in the fusion-intermediate conformation. The 1B5 group competes with co-receptor binding and the 1F10 group interacts with the crown of the gp120 V3 loop, occluded in native Env. We present biophysical and structural details on the 2E7 interaction with gp41. In order to further increase breadth and potency, we constructed bi-specific VHH. The combination of CD4bs VHH (J3/3E3) with 2E7 group VHH enhanced strain-specific neutralization with potencies up to 1400-fold higher than the mixture of the individual VHHs. Thus, these new bivalent VHH are potent new tools to develop therapeutic approaches or microbicide intervention.

| S-EPMC6640723 | biostudies-literature

Broad and potent HIV-1 neutralization by a human antibody that binds the gp41-gp120 interface.

Project description:The isolation of human monoclonal antibodies is providing important insights into the specificities that underlie broad neutralization of HIV-1 (reviewed in ref. 1). Here we report a broad and extremely potent HIV-specific monoclonal antibody, termed 35O22, which binds a novel HIV-1 envelope glycoprotein (Env) epitope. 35O22 neutralized 62% of 181 pseudoviruses with a half-maximum inhibitory concentration (IC50) <50 ?g ml(-1). The median IC50 of neutralized viruses was 0.033 ?g ml(-1), among the most potent thus far described. 35O22 did not bind monomeric forms of Env tested, but did bind the trimeric BG505 SOSIP.664. Mutagenesis and a reconstruction by negative-stain electron microscopy of the Fab in complex with trimer revealed that it bound to a conserved epitope, which stretched across gp120 and gp41. The specificity of 35O22 represents a novel site of vulnerability on HIV Env, which serum analysis indicates to be commonly elicited by natural infection. Binding to this new site of vulnerability may thus be an important complement to current monoclonal-antibody-based approaches to immunotherapies, prophylaxis and vaccine design.

| S-EPMC4224615 | biostudies-literature

Rapid development of glycan-specific, broad, and potent anti-HIV-1 gp120 neutralizing antibodies in an R5 SIV/HIV chimeric virus infected macaque.

Project description:It is widely believed that the induction of a broadly neutralizing antibody (bNAb) response will be a critical component of a successful vaccine against HIV. A significant fraction of HIV-infected individuals mount bNAb responses, providing support for the notion that such responses could be elicited through vaccination. Infection of macaques with simian immunodeficiency virus (SIV) or SIV/HIV chimeric virus (SHIV) has been widely used to model aspects of HIV infection, but to date, only limited bNAb responses have been described. Here, we screened plasma from 14 R5-tropic SHIV-infected macaques for broadly neutralizing activity and identified a macaque with highly potent cross-clade plasma NAb response. Longitudinal studies showed that the development of broad and autologous NAb responses occurred coincidentally in this animal. Serum-mapping studies, using pseudovirus point mutants and antigen adsorption assays, indicated that the plasma bNAbs are specific for epitopes that include carbohydrates and are critically dependent on the glycan at position 332 of Env gp120. The results described herein provide insight into the development and evolution of a broad response, suggest that certain bNAb specificities may be more rapidly induced by immunization than others, and provide a potential model for the facile study of the development of bNAb responses.

| S-EPMC3250170 | biostudies-literature

Potent strategy to inhibit HIV-1 by binding both gp120 and gp41.

Project description:The development of an anti-HIV microbicide is critical in the fight against the spread of HIV. It is shown here that the covalent linking of compounds that bind gp120 with compounds that bind gp41 can inhibit HIV entry even more potently than individual inhibitors or noncovalent combinations. The most striking example involves griffithsin, a potent HIV inhibitor that binds to the surface of HIV gp120. While griffithsin inhibits HIV Env-mediated fusion in a CCR5-tropic cell-cell fusion assay with a 50% inhibitory concentration (IC(50)) of 1.31 ± 0.87 nM and the gp41-binding peptide C37 shows an IC(50) of 18.2 ± 7.6 nM, the covalently linked combination of griffithsin with C37 (Griff37) has an IC(50) of 0.15 ± 0.05 nM, exhibiting a potency 8.7-fold greater than that of griffithsin alone. Similarly, in CXCR4-tropic cell-cell fusion assays, Griff37 is 5.2-fold more potent than griffithsin alone. In viral assays, both griffithsin and Griff37 inhibit HIV replication at midpicomolar levels, but the linked compound Griff37 is severalfold more potent than griffithsin alone against both CCR5- and CXCR4-tropic virus strains. Another example of this strategy is the covalently linked combination of peptide C37 with a variant of the gp120-binding peptide CD4M33 (L. Martin et al., Nat. Biotechnol. 21:71-76, 2003). Also, nuclear magnetic resonance (NMR) spectra for several of these compounds are shown, including, to our knowledge, the first published NMR spectrum for griffithsin.

| S-EPMC3019634 | biostudies-literature

HIV-1 gp41 core with exposed membrane-proximal external region inducing broad HIV-1 neutralizing antibodies.

Project description:The membrane-proximal external region (MPER) of the HIV-1 gp41 consists of epitopes for the broadly cross-neutralizing monoclonal antibodies 2F5 and 4E10. However, antigens containing the linear sequence of these epitopes are unable to elicit potent and broad neutralizing antibody responses in vaccinated hosts, possibly because of inappropriate conformation of these epitopes. Here we designed a recombinant antigen, designated NCM, which comprises the N- and C-terminal heptad repeats that can form a six-helix bundle (6HB) core and the MPER domain of gp41. Two mutations (T569A and I675V) previously reported to expose the neutralization epitopes were introduced into NCM to generate mutants named NCM(TA), NCM(IV), and NCM(TAIV). Our results showed that NCM and its mutants could react with antibodies specific for 6HB and MPER of gp41, suggesting that these antigens are in the form of a trimer of heterodimer (i.e., 6HB) with three exposed MPER tails. Antigen with double mutations, NCM(TAIV), elicited much stronger antibody response in rabbits than immunogens with single mutation, NCM(TA) and NCM(IV), or no mutation, NCM. The purified MPER-specific antibodies induced by NCM(TAIV) exhibited broad neutralizing activity, while the purified 6HB-specific antibodies showed no detectable neutralizing activity. Our recombinant antigen design supported by an investigation of its underlying molecular mechanisms provides a strong scientific platform for the discovery of a gp41 MPER-based AIDS vaccine.

| S-EPMC3069051 | biostudies-literature

Broad and potent neutralization of HIV-1 by a gp41-specific human antibody.

Project description:Characterization of human monoclonal antibodies is providing considerable insight into mechanisms of broad HIV-1 neutralization. Here we report an HIV-1 gp41 membrane-proximal external region (MPER)-specific antibody, named 10E8, which neutralizes ∼98% of tested viruses. An analysis of sera from 78 healthy HIV-1-infected donors demonstrated that 27% contained MPER-specific antibodies and 8% contained 10E8-like specificities. In contrast to other neutralizing MPER antibodies, 10E8 did not bind phospholipids, was not autoreactive, and bound cell-surface envelope. The structure of 10E8 in complex with the complete MPER revealed a site of vulnerability comprising a narrow stretch of highly conserved gp41-hydrophobic residues and a critical arginine or lysine just before the transmembrane region. Analysis of resistant HIV-1 variants confirmed the importance of these residues for neutralization. The highly conserved MPER is a target of potent, non-self-reactive neutralizing antibodies, suggesting that HIV-1 vaccines should aim to induce antibodies to this region of HIV-1 envelope glycoprotein.

| S-EPMC4854285 | biostudies-literature

Design of an Escherichia coli expressed HIV-1 gp120 fragment immunogen that binds to b12 and induces broad and potent neutralizing antibodies.

Project description:b12, one of the few broadly neutralizing antibodies against HIV-1, binds to the CD4 binding site (CD4bs) on the gp120 subunit of HIV-1 Env. Two small fragments of HIV-1 gp120, b121a and b122a, which display about 70% of the b12 epitope and include solubility-enhancing mutations, were designed. Bacterially expressed b121a/b122a were partially folded and could bind b12 but not the CD4bs-directed non-neutralizing antibody b6. Sera from rabbits primed with b121a or b122a protein fragments and boosted with full-length gp120 showed broad neutralizing activity in a TZM-bl assay against a 16-virus panel that included nine Tier 2 and 3 viruses as well as in a five-virus panel previously designed to screen for broad neutralization. Using a mean IC50 cut-off of 50, sera from control rabbits immunized with gp120 alone neutralized only one virus of the 14 non-Tier 1 viruses tested (7%), whereas sera from b121a- and b122a-immunized rabbits neutralized seven (50%) and twelve (86%) viruses, respectively. Serum depletion studies confirmed that neutralization was gp120-directed and that sera from animals immunized with gp120 contained lower amounts of CD4bs-directed antibodies than corresponding sera from animals immunized with b121a/b122a. Competition binding assays with b12 also showed that b121a/2a sera contained significantly higher amounts of antibodies directed toward the CD4 binding site than the gp120 sera. The data demonstrate that it is possible to elicit broadly neutralizing sera against HIV-1 in small animals.

| S-EPMC3617282 | biostudies-literature

HIV-1 envelope trimer elicits more potent neutralizing antibody responses than monomeric gp120.

Project description:HIV-1 envelope glycoprotein is the primary target for HIV-1-specific antibodies. The native HIV-1 envelope spike on the virion surface is a trimer, but trimeric gp140 and monomeric gp120 currently are believed to induce comparable immune responses. Indeed, most studies on the immunogenicity of HIV-1 envelope oligomers have revealed only marginal improvement over monomers. We report here that suitably prepared envelope trimers have nearly all the antigenic properties expected for native viral spikes. These stable, rigorously homogenous trimers have antigenic properties markedly different from those of monomeric gp120s derived from the same sequences, and they induce potent neutralizing antibody responses for a cross-clade set of tier 1 and tier 2 viruses with titers substantially higher than those elicited by the corresponding gp120 monomers. These results, which demonstrate that there are relevant immunologic differences between monomers and high-quality envelope trimers, have important implications for HIV-1 vaccine development.

| S-EPMC3409750 | biostudies-literature

Neutralizing Antibodies Targeting HIV-1 gp41.

Project description:HIV-1 vaccine research has obtained an enormous boost since the discovery of many broadly neutralizing antibodies (bnAbs) targeting all accessible sites on the HIV-1 envelope glycoprotein (Env). This in turn facilitated high-resolution structures of the Env glycoprotein in complex with bnAbs. Here we focus on gp41, its highly conserved heptad repeat region 1 (HR1), the fusion peptide (FP) and the membrane-proximal external region (MPER). Notably, the broadest neutralizing antibodies target MPER. Both gp41 HR1 and MPER are only fully accessible once receptor-induced conformational changes have taken place, although some studies suggest access to MPER in the close to native Env conformation. We summarize the data on the structure and function of neutralizing antibodies targeting gp41 HR1, FP and MPER and we review their access to Env and their complex formation with gp41 HR1, MPER peptides and FP within native Env. We further discuss MPER bnAb binding to lipids and the role of somatic mutations in recognizing a bipartite epitope composed of the conserved MPER sequence and membrane components. The problematic of gp41 HR1 access and MPER bnAb auto- and polyreactivity is developed in the light of inducing such antibodies by vaccination.

| S-EPMC7690876 | biostudies-literature

Peptide mimic of the HIV envelope gp120-gp41 interface.

Project description:The human immunodeficiency virus envelope glycoprotein (Env) is composed of surface (gp120) and transmembrane (gp41) subunits, which are noncovalently associated on the viral surface. Human immunodeficiency virus Env mediates viral entry after undergoing a complex series of conformational changes induced by interaction with cellular CD4 and a chemokine coreceptor. These changes propagate from gp120 to gp41 via the gp120-gp41 interface, ultimately exposing gp41 and allowing it to form the trimer-of-hairpins structure that provides the driving force for membrane fusion. Key unresolved questions about the gp120-gp41 interface include the specific regions of gp41 and gp120 involved, the mechanism by which receptor and coreceptor-binding-induced conformational changes in gp120 are communicated to gp41, how trimer-of-hairpins formation is prevented in the prefusogenic gp120-gp41 complex, and, ultimately, the structure of the prefusion gp120-gp41 complex. Here, we develop a biochemical model system that mimics a key portion of the gp120-gp41 interface in the prefusogenic state. We find that a gp41 fragment containing the disulfide bond loop and C-peptide region binds primarily to the gp120 C5 region and that this interaction is incompatible with trimer-of-hairpins formation. Based on these data, we propose that in prefusogenic Env, gp120 sequesters the gp41 C-peptide region away from the N-trimer region, preventing trimer-of-hairpins formation until coreceptor binding disrupts this interface. This model system is a valuable tool for studying the gp120-gp41 complex, conformational changes induced by CD4 and coreceptor binding, and the mechanism of membrane fusion.

| S-EPMC2265733 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data