A human monoclonal antibody against the CD4-binding site of HIV1 gp120 exhibits potent, broadly neutralizing activity

ABSTRACT We isolated a human monoclonal antibody against diphtheria toxin (DT). It bound to fragment B with a binding activity (Kd ) of 3.01 nM. The neutralizing activity assayed by the rabbit skin test was estimated to be 73,600 IU/g. This could be used as a therapeutic drug against DT in place of the traditional equine sera.

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A novel site contributing to growth-arrest-specific gene 6 binding to its receptors as revealed by a human monoclonal antibody

Biochemical Journal ◽

10.1042/bj20040859 ◽

2005 ◽

Vol 387 (3) ◽

pp. 727-735 ◽

Cited By ~ 28

Author(s):

Paul W. FISHER ◽

Michael BRIGHAM-BURKE ◽

Sheng-Jiun WU ◽

Jinquan LUO ◽

Jill CARTON ◽

...

Keyword(s):

Monoclonal Antibody ◽

Binding Site ◽

Receptor Binding ◽

Human Monoclonal Antibody ◽

Growth Arrest ◽

Peptide Sequence ◽

Receptor Interaction ◽

Specific Gene ◽

Dependent Manner ◽

Hydrophobic Patch

Gas6 (growth-arrest-specific gene 6) is a vitamin K-dependent protein known to activate the Axl family of receptor tyrosine kinases. It is an important regulator of thrombosis and many other biological functions. The C-terminus of Gas6 binds to receptors and consists of two laminin-like globular domains LG1 and LG2. It has been reported that a Ca2+-binding site at the junction of LG1 and LG2 domains and a hydrophobic patch at the LG2 domain are important for receptor binding [Sasaki, Knyazev, Cheburkin, Gohring, Tisi, Ullrich, Timpl and Hohenester (2002) J. Biol. Chem. 277, 44164–44170]. In the present study, we developed a neutralizing human monoclonal antibody, named CNTO300, for Gas6. The antibody was generated by immunization of human IgG-expressing transgenic mice with recombinant human Gas6 protein and the anti-Gas6 IgG sequences were rescued from an unstable hybridoma clone. Binding of Gas6 to its receptors was partially inhibited by the CNTO300 antibody in a dose-dependent manner. To characterize further the interaction between Gas6 and this antibody, the binding kinetics of CNTO300 for recombinant Gas6 were compared with independently expressed LG1 and LG2. The CNTO300 antibody showed comparable binding affinity, yet different dependence on Ca2+, to Gas6 and LG1. No binding to LG2 was detected. In the presence of EDTA, binding of the antibody to Gas6 was disrupted, but no significant effect of EDTA on LG1 binding was evident. Further epitope mapping identified a Gas6 peptide sequence recognized by the CNTO300 antibody. This peptide sequence was found to be located at the LG1 domain distant from the Ca2+-binding site and the hydrophobic patch. Co-interaction of Gas6 with its receptor and CNTO300 antibody was detected by BIAcore analysis, suggesting a second receptor-binding site on the LG1 domain. This hypothesis was further supported by direct binding of Gas6 receptors to an independently expressed LG1 domain. Our results revealed, for the first time, a second binding site for Gas6–receptor interaction.

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Synergistic neutralization of human immunodeficiency virus type 1 by a chimpanzee monoclonal antibody against the V2 domain of gp120 in combination with monoclonal antibodies against the V3 loop and the CD4-binding site.

Journal of Virology ◽

10.1128/jvi.70.7.4466-4473.1996 ◽

1996 ◽

Vol 70 (7) ◽

pp. 4466-4473 ◽

Cited By ~ 35

Author(s):

S Vijh-Warrier ◽

A Pinter ◽

W J Honnen ◽

S A Tilley

Keyword(s):

Monoclonal Antibody ◽

Human Immunodeficiency Virus ◽

Monoclonal Antibodies ◽

Binding Site ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

V3 Loop ◽

Immunodeficiency Virus ◽

Cd4 Binding Site

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Neutralization Characteristics HIV-1 CRF01_AE Env Clones from Infections in China

10.21203/rs.3.rs-568729/v1 ◽

2021 ◽

Author(s):

Xinyu Zhang ◽

Zehua Zhou ◽

Xueli Li ◽

Yimeng An ◽

Fei Jiang ◽

...

Keyword(s):

Monoclonal Antibodies ◽

Binding Site ◽

External Region ◽

Sugar Chain ◽

Neutralizing Activity ◽

Cd4 Binding Site ◽

Anti Hiv ◽

V3 Region ◽

Hiv 1 ◽

V1v2 Region

Abstract Owing to the increasing prevalence of HIV-1 CRF_01AE, it is necessary to understand the neutralization properties of CRF_01AE and to develop broadly neutralizing monoclonal antibodies (bnmAbs) that can neutralize this virus. The full-length Env gene was cloned from HIV-1 CRF01_AE-infected plasma specimens collected in China and used to establish pseudoviruses. Neutralization phenotypes of the pseudoviruses were characterized with bnmAbs. The neutralizing activities of 11 bnmAbs VRC01, VRC03, IgG1b12 and 3BNC117 (targeting the CD4 binding site); PG9 (targeting the V1V2 region); 2G12 (sugar chain specific), PGT135 and 10-1074 (targeting the V3 region); 2F5, 4E10 and 10E8 (targeting the membrane proximal external region), against 36 pseudoviruses were analyzed, demonstrating varying efficacies. In general, VRC01, 10E8 and 3BNC117 showed strong neutralizing activity, neutralizing more than 75% of the pseudoviruses; followed by PG9 and 4E10, showing moderate neutralizing activity with neutralization of 50%–60% of the pseudoviruses; whereas the efficacies of the remaining bnmAbs were poor, neutralizing less than 15% of pseudoviruses tested. Env variants of CRF_01AE also showed significant differences in resistance to neutralization. CRF_01AE Env variants pose a serious challenge for the development of bnmAbs and vaccines, and these characterized HIV-1 CRF_01AE pseudoviruses could be used for neutralization studies and evaluation of vaccines or anti-HIV-1 products in China.

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Potent binding of 2019 novel coronavirus spike protein by a SARS coronavirus-specific human monoclonal antibody

10.1101/2020.01.28.923011 ◽

2020 ◽

Cited By ~ 13

Author(s):

Xiaolong Tian ◽

Cheng Li ◽

Ailing Huang ◽

Shuai Xia ◽

Sicong Lu ◽

...

Keyword(s):

Monoclonal Antibody ◽

Binding Site ◽

Neutralizing Antibodies ◽

Rapid Development ◽

Antiviral Treatment ◽

Human Monoclonal Antibody ◽

Cross Reactivity ◽

Spike Protein ◽

The Cross ◽

Novel Coronavirus

ABSTRACTThe newly identified 2019 novel coronavirus (2019-nCoV) has caused more than 800 laboratory-confirmed human infections, including 25 deaths, posing a serious threat to human health. Currently, however, there is no specific antiviral treatment or vaccine. Considering the relatively high identity of receptor binding domain (RBD) in 2019-nCoV and SARS-CoV, it is urgent to assess the cross-reactivity of anti-SARS-CoV antibodies with 2019-nCoV spike protein, which could have important implications for rapid development of vaccines and therapeutic antibodies against 2019-nCoV. Here, we report for the first time that a SARS-CoV-specific human monoclonal antibody, CR3022, could bind potently with 2019-nCoV RBD (KD of 6.3 nM). The epitope of CR3022 does not overlap with the ACE2 binding site within 2019-nCoV RBD. Therefore, CR3022 has the potential to be developed as candidate therapeutics, alone or in combination with other neutralizing antibodies, for the prevention and treatment of 2019-nCoV infections. Interestingly, some of the most potent SARS-CoV-specific neutralizing antibodies (e.g., m396, CR3014) that target the ACE2 binding site of SARS-CoV failed to bind 2019-nCoV spike protein, indicating that the difference in the RBD of SARS-CoV and 2019-nCoV has a critical impact for the cross-reactivity of neutralizing antibodies, and that it is still necessary to develop novel monoclonal antibodies that could bind specifically to 2019-nCoV RBD.

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