scholarly journals Characterization of T cell-expressed chimeric receptors with antibody-type specificity for the CD4 binding site of HIV-1 gp120

1998 ◽  
Vol 28 (12) ◽  
pp. 4177-4187 ◽  
Author(s):  
Natacha Bitton ◽  
Florence Verrier ◽  
Patrice Debré ◽  
Guy Gorochov
Keyword(s):  
T Cell ◽  
Binding Site ◽  
Chimeric Receptors ◽  
Cd4 Binding Site ◽  
Hiv 1

scholarly journals HIV-1 R5 Macrophage-Tropic Envelope Glycoprotein Trimers Bind CD4 with High Affinity, while the CD4 Binding Site on Non-macrophage-tropic, T-Tropic R5 Envelopes Is Occluded

2017 ◽  
Vol 92 (2) ◽  
Author(s):  
Briana Quitadamo ◽  
Paul J. Peters ◽  
Alexander Repik ◽  
Olivia O'Connell ◽  
Zhongming Mou ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Binding Site ◽  
Envelope Protein ◽  
High Avidity ◽  
Immune Tissue ◽  
Coreceptor Binding ◽  
Cd4 Binding Site ◽  
Low Levels ◽  
Hiv 1

ABSTRACTHIV-1 R5 variants exploit CCR5 as a coreceptor to infect both T cells and macrophages. R5 viruses that are transmitted or derived from immune tissue and peripheral blood are mainly inefficient at mediating infection of macrophages. In contrast, highly macrophage-tropic (mac-tropic) R5 viruses predominate in brain tissue and can be detected in cerebrospinal fluid but are infrequent in immune tissue or blood even in late disease. These mac-tropic R5 variants carry envelope glycoproteins (Envs) adapted to exploit low levels of CD4 on macrophages to induce infection. However, it is unclear whether this adaptation is conferred by an increased affinity of the Env trimer for CD4 or is mediated by postbinding structural rearrangements in the trimer that enhance the exposure of the coreceptor binding site and facilitate events leading to fusion and virus entry. In this study, we investigated CD4 binding to mac-tropic and non-mac-tropic Env trimers and showed that CD4-IgG binds efficiently to mac-tropic R5 Env trimers, while binding to non-mac-tropic trimers was undetectable. Our data indicated that the CD4 binding site (CD4bs) is highly occluded on Env trimers of non-mac-tropic R5 viruses. Such viruses may therefore infect T cells via viral synapses where Env and CD4 become highly concentrated. This environment will enable high-avidity interactions that overcome extremely low Env-CD4 affinities.IMPORTANCEHIV R5 variants bind to CD4 and CCR5 receptors on T cells and macrophages to initiate infection. Transmitted HIV variants infect T cells but not macrophages, and these viral strains persist in immune tissue even in late disease. Here we show that the binding site for CD4 present on HIV's envelope protein is occluded on viruses replicating in immune tissue. This occlusion likely prevents antibody binding to this site and neutralization of the virus, but it makes it difficult for virus-CD4 interactions to occur. Such viruses probably pass from T cell to T cell via cell contacts where CD4 is highly concentrated and allows infection via inefficient envelope-CD4 binding. Our data are highly relevant for vaccines that aim to induce antibodies targeting the CD4 binding site on the envelope protein.

scholarly journals Characterization of a vaccine-elicited human antibody with sequence homology to VRC01-class antibodies that binds the C1C2 gp120 domain

2021 ◽  
Author(s):  
Matthew D Gray ◽  
Junli Feng ◽  
Connor E Weidle ◽  
Kristen W Cohen ◽  
Lamar Ballweber-Fleming ◽  
...  
Keyword(s):  
B Cells ◽  
Binding Site ◽  
Sequence Homology ◽  
Human Antibody ◽  
Heavy Chains ◽  
Vaccine Trials ◽  
Class B ◽  
Cd4 Binding Site ◽  
Hiv 1

Broadly HIV-1 neutralizing VRC01-class antibodies bind the CD4-binding site of the HIV-1 envelope (Env) and contain VH1-2*02-derived heavy chains paired with light chains expressing five amino acid long CDRL3s. Their unmutated forms do not recognize Env or neutralize HIV-1. The lack of elicitation of VRC01-class antibodies in human clinical trials could potentially be due to the absence of activation of the corresponding naive B cells by the vaccine Env immunogens. To address this point directly, we examined Env-specific BCR sequences from participants in the HVTN 100 clinical trial. Of all the sequences analyzed only one displayed sequence homology to VRC01-class antibodies, but the corresponding antibody (FH1) recognized the C1C2 gp120 domain. For FH1 to switch epitope recognition to the CD4-binding site, alterations in both the CDRH3 and CDRL3 were necessary. Our findings support the use of specifically designed immunogens to activate VRC01-class B cells in future human vaccine trials.

scholarly journals Inhibition of Virus Attachment to CD4+ Target Cells Is a Major Mechanism of T Cell Line–adapted HIV-1 Neutralization

1997 ◽  
Vol 186 (8) ◽  
pp. 1287-1298 ◽  
Author(s):  
Sophie Ugolini ◽  
Isabelle Mondor ◽  
Paul W.H.I. Parren ◽  
Dennis R. Burton ◽  
Shermaine A. Tilley ◽  
...  
Keyword(s):  
T Cell ◽  
Binding Site ◽  
Cell Line ◽  
Target Cells ◽  
Cd4 Cells ◽  
Cell Binding ◽  
Major Mechanism ◽  
Cd4 Binding Site ◽  
Hiv 1 ◽  
Soluble Cd4

Antibody-mediated neutralization of human immunodeficiency virus type–1 (HIV-1) is thought to function by at least two distinct mechanisms: inhibition of virus–receptor binding, and interference with events after binding, such as virus–cell membrane fusion. Here we show, by the use of a novel virus–cell binding assay, that soluble CD4 and monoclonal antibodies to all confirmed glycoprotein (gp)120 neutralizing epitopes, including the CD4 binding site and the V2 and V3 loops, inhibit the adsorption of two T cell line–adapted HIV-1 viruses to CD4+ cells. A correlation between the inhibition of virus binding and virus neutralization was observed for soluble CD4 and all anti-gp120 antibodies, indicating that this is a major mechanism of HIV neutralization. By contrast, antibodies specific for regions of gp120 other than the CD4 binding site showed little or no inhibition of either soluble gp120 binding to CD4+ cells or soluble CD4 binding to HIV-infected cells, implying that this effect is specific to the virion–cell interaction. However, inhibition of HIV-1 attachment to cells is not a universal mechanism of neutralization, since an anti-gp41 antibody did not inhibit virus–cell binding at neutralizing concentrations, implying activity after virus–cell binding.

Isolation and characterization of a novel neutralizing antibody targeting the CD4-binding site of HIV-1 gp120

2016 ◽  
Vol 132 ◽  
pp. 252-261 ◽  
Author(s):  
Yuanyuan Qiao ◽  
Lai Man ◽  
Zonglin Qiu ◽  
Lingli Yang ◽  
Youxiang Sun ◽  
...  
Keyword(s):  
Binding Site ◽  
Neutralizing Antibody ◽  
Isolation And Characterization ◽  
Cd4 Binding Site ◽  
Antibody Targeting ◽  
Hiv 1

Structural characterization of broadly neutralizing human monoclonal antibodies against the CD4 binding site of HIV-1 gp120

1994 ◽  
Vol 31 (15) ◽  
pp. 1149-1160 ◽  
Author(s):  
Jessamyn Bagley ◽  
Patrick J. Dillon ◽  
Craig Rosen ◽  
James Robinson ◽  
Joseph Sodroski ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Binding Site ◽  
Structural Characterization ◽  
Human Monoclonal Antibodies ◽  
Cd4 Binding Site ◽  
Hiv 1

scholarly journals Neutralization Properties of Simian Immunodeficiency Viruses Infecting Chimpanzees and Gorillas

mBio ◽  
2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Hannah J. Barbian ◽  
Julie M. Decker ◽  
Frederic Bibollet-Ruche ◽  
Rachel P. Galimidi ◽  
Anthony P. West ◽  
...  
Keyword(s):  
T Cells ◽  
Binding Site ◽  
Pan Troglodytes ◽  
Neutralizing Antibodies ◽  
Gorilla Gorilla ◽  
Protective Capacity ◽  
Content Type ◽  
Ccr5 Receptor ◽  
Cd4 Binding Site ◽  
Hiv 1

ABSTRACTBroadly cross-reactive neutralizing antibodies (bNabs) represent powerful tools to combat human immunodeficiency virus type 1 (HIV-1) infection. Here, we examined whether HIV-1-specific bNabs are capable of cross-neutralizing distantly related simian immunodeficiency viruses (SIVs) infecting central (Pan troglodytestroglodytes) (SIVcpzPtt) and eastern (Pan troglodytesschweinfurthii) (SIVcpzPts) chimpanzees (n= 11) as well as western gorillas (Gorilla gorilla gorilla) (SIVgor) (n= 1). We found that bNabs directed against the CD4 binding site (n= 10), peptidoglycans at the base of variable loop 3 (V3) (n= 5), and epitopes at the interface of surface (gp120) and membrane-bound (gp41) envelope glycoproteins (n= 5) failed to neutralize SIVcpz and SIVgor strains. In addition, apex V2-directed bNabs (n= 3) as well as llama-derived (heavy chain only) antibodies (n= 6) recognizing both the CD4 binding site and gp41 epitopes were either completely inactive or neutralized only a fraction of SIVcpzPttstrains. In contrast, one antibody targeting the membrane-proximal external region (MPER) of gp41 (10E8), functional CD4 and CCR5 receptor mimetics (eCD4-Ig, eCD4-Igmim2, CD4-218.3-E51, and CD4-218.3-E51-mim2), as well as mono- and bispecific anti-human CD4 (iMab and LM52) and CCR5 (PRO140, PRO140-10E8) receptor antibodies neutralized >90% of SIVcpz and SIVgor strains with low-nanomolar (0.13 to 8.4 nM) potency. Importantly, the latter antibodies blocked virus entry not only in TZM-bl cells but also in Cf2Th cells expressing chimpanzee CD4 and CCR5 and neutralized SIVcpz in chimpanzee CD4+T cells, with 50% inhibitory concentrations (IC50s) ranging from 3.6 to 40.5 nM. These findings provide new insight into the protective capacity of anti-HIV-1 bNabs and identify candidates for further development to combat SIVcpz infection.IMPORTANCESIVcpz is widespread in wild-living chimpanzees and can cause AIDS-like immunopathology and clinical disease. HIV-1 infection of humans can be controlled by antiretroviral therapy; however, treatment of wild-living African apes with current drug regimens is not feasible. Nonetheless, it may be possible to curb the spread of SIVcpz in select ape communities using vectored immunoprophylaxis and/or therapy. Here, we show that antibodies and antibody-like inhibitors developed to combat HIV-1 infection in humans are capable of neutralizing genetically diverse SIVcpz and SIVgor strains with considerable breadth and potency, including in primary chimpanzee CD4+T cells. These reagents provide an important first step toward translating intervention strategies currently developed to treat and prevent AIDS in humans to SIV-infected apes.

scholarly journals Broad neutralization by a combination of antibodies recognizing the CD4 binding site and a new conformational epitope on the HIV-1 envelope protein

2012 ◽  
Vol 209 (8) ◽  
pp. 1469-1479 ◽  
Author(s):  
Florian Klein ◽  
Christian Gaebler ◽  
Hugo Mouquet ◽  
D. Noah Sather ◽  
Clara Lehmann ◽  
...  
Keyword(s):  
Binding Site ◽  
Envelope Protein ◽  
Neutralizing Antibodies ◽  
Conformational Epitope ◽  
Broadly Neutralizing Antibodies ◽  
Cd4 Binding Site ◽  
Capture Method ◽  
Anti Hiv ◽  
Hiv 1 ◽  
Viral Isolates

Two to three years after infection, a fraction of HIV-1–infected individuals develop serologic activity that neutralizes most viral isolates. Broadly neutralizing antibodies that recognize the HIV-1 envelope protein have been isolated from these patients by single-cell sorting and by neutralization screens. Here, we report a new method for anti–HIV-1 antibody isolation based on capturing single B cells that recognize the HIV-1 envelope protein expressed on the surface of transfected cells. Although far less efficient than soluble protein baits, the cell-based capture method identified antibodies that bind to a new broadly neutralizing epitope in the vicinity of the V3 loop and the CD4-induced site (CD4i). The new epitope is expressed on the cell surface form of the HIV-1 spike, but not on soluble forms of the same envelope protein. Moreover, the new antibodies complement the neutralization spectrum of potent broadly neutralizing anti-CD4 binding site (CD4bs) antibodies obtained from the same individual. Thus, combinations of potent broadly neutralizing antibodies with complementary activity can account for the breadth and potency of naturally arising anti–HIV-1 serologic activity. Therefore, vaccines aimed at eliciting anti–HIV-1 serologic breadth and potency should not be limited to single epitopes.

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