IgG2 inhibits HIV-1 internalization by monocytes, and IgG subclass binding is affected by gp120 glycosylation

ABSTRACT Griffithsin (Grft) is an antiviral lectin that has been shown to potently inhibit HIV-1 by binding high-mannose N-linked glycosylation sites on HIV-1 gp120. A key factor for Grft potency is glycosylation at N295 of gp120, which is directly adjacent to N332, a target glycan for an entire class of broadly neutralizing antibodies (bNAbs). Here, we unify previous work on the importance of other glycans to Grft potency against HIV-1 and Grft’s role in mediating the conformational change of gp120 by mutating nearly every glycosylation site in gp120. In addition to a significant loss of Grft activity by the removal of glycosylation at N295, glycan absence at N332 or N448 was found to have moderate effects on Grft potency. Interestingly, in the absence of N295, Grft effectiveness could be improved by a mutation that results in the glycan at N448 shifting to N446, indicating that the importance of individual glycans may be related to their effect on glycosylation density. Grft’s ability to alter the structure of gp120, exposing the CD4 binding site, correlated with the presence of glycosylation at N295 only in clade B strains, not clade C strains. We further demonstrate that Grft can rescue the activity of the bNAbs PGT121 and PGT126 in the event of a loss or a shift of glycosylation at N332, where the bNAbs suffer a drastic loss of potency. Despite targeting the same region, Grft in combination with PGT121 and PGT126 produced additive effects. This indicates that Grft could be an important combinational therapeutic.

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Characterization of IgG and IgG Subclass Antibodies Present in Paired Maternal and Fetal Serum Which Are Directed Against HIV-1 Proteins

AIDS Research and Human Retroviruses ◽

10.1089/aid.1991.7.847 ◽

1991 ◽

Vol 7 (10) ◽

pp. 847-854 ◽

Cited By ~ 8

Author(s):

TOBIAS R. KOLLMANN ◽

ARYE RUBINSTEIN ◽

WILLIAM D. LYMAN ◽

RUY SOEIRO ◽

HARRIS GOLDSTEIN

Keyword(s):

Igg Subclass ◽

Fetal Serum ◽

Hiv 1

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Differential IgG Subclass Responses to Epitopes in Transmembrane Protein of HIV-1

Viral Immunology ◽

10.1089/vim.1990.3.89 ◽

1990 ◽

Vol 3 (2) ◽

pp. 89-98 ◽

Cited By ~ 4

Author(s):

PER JOHAN KLASSE ◽

JONAS BLOMBERG ◽

RÜDIGER PIPKORN

Keyword(s):

Transmembrane Protein ◽

Igg Subclass ◽

Hiv 1

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Comparison of the Specificities of IgG, IgG-Subclass, IgA and IgM Reactivities in African and European HIV-Infected Individuals with an HIV-1 Clade C Proteome-Based Array

PLoS ONE ◽

10.1371/journal.pone.0117204 ◽

2015 ◽

Vol 10 (2) ◽

pp. e0117204 ◽

Cited By ~ 7

Author(s):

Daniela Gallerano ◽

Portia Ndlovu ◽

Ian Makupe ◽

Margarete Focke-Tejkl ◽

Kerstin Fauland ◽

...

Keyword(s):

Igg Subclass ◽

Clade C ◽

Hiv 1

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Structure and Fc-Effector Function of Rhesusized Variants of Human Anti-HIV-1 IgG1s

Frontiers in Immunology ◽

10.3389/fimmu.2021.787603 ◽

2022 ◽

Vol 12 ◽

Author(s):

William D. Tolbert ◽

Dung N. Nguyen ◽

Marina Tuyishime ◽

Andrew R. Crowley ◽

Yaozong Chen ◽

...

Keyword(s):

A Priori ◽

Conformational Epitope ◽

Effector Function ◽

Igg Subclass ◽

Human Mabs ◽

Loop Region ◽

Dependent Cell ◽

Env Antigens ◽

Complementarity Determining Regions ◽

Hiv 1

Passive transfer of monoclonal antibodies (mAbs) of human origin into Non-Human Primates (NHPs), especially those which function predominantly by a Fc-effector mechanism, requires an a priori preparation step, in which the human mAb is reengineered to an equivalent NHP IgG subclass. This can be achieved by changing both the Fc and Fab sequence while simultaneously maintaining the epitope specificity of the parent antibody. This Ab reengineering process, referred to as rhesusization, can be challenging because the simple grafting of the complementarity determining regions (CDRs) into an NHP IgG subclass may impact the functionality of the mAb. Here we describe the successful rhesusization of a set of human mAbs targeting HIV-1 envelope (Env) epitopes involved in potent Fc-effector function against the virus. This set includes a mAb targeting a linear gp120 V1V2 epitope isolated from a RV144 vaccinee, a gp120 conformational epitope within the Cluster A region isolated from a RV305 vaccinated individual, and a linear gp41 epitope within the immunodominant Cys-loop region commonly targeted by most HIV-1 infected individuals. Structural analyses confirm that the rhesusized variants bind their respective Env antigens with almost identical specificity preserving epitope footprints and most antigen-Fab atomic contacts with constant regions folded as in control RM IgG1s. In addition, functional analyses confirm preservation of the Fc effector function of the rhesusized mAbs including the ability to mediate Antibody Dependent Cell-mediated Cytotoxicity (ADCC) and antibody dependent cellular phagocytosis by monocytes (ADCP) and neutrophils (ADNP) with potencies comparable to native macaque antibodies of similar specificity. While the antibodies chosen here are relevant for the examination of the correlates of protection in HIV-1 vaccine trials, the methods used are generally applicable to antibodies for other purposes.

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Metabolic labeling of HIV-1 envelope glycoprotein gp120 to elucidate the effect of gp120 glycosylation on antigen uptake

Journal of Biological Chemistry ◽

10.1074/jbc.ra118.004798 ◽

2018 ◽

Vol 293 (39) ◽

pp. 15178-15194 ◽

Cited By ~ 2

Author(s):

Lina Sun ◽

Mayumi Ishihara ◽

Dustin R. Middleton ◽

Michael Tiemeyer ◽

Fikri Y. Avci

Keyword(s):

Envelope Glycoprotein ◽

Metabolic Labeling ◽

Antigen Uptake ◽

Envelope Glycoprotein Gp120 ◽

Glycoprotein Gp120 ◽

Gp120 Glycosylation ◽

Hiv 1

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Distinct, IgG1-driven antibody response landscapes demarcate individuals with broadly HIV-1 neutralizing activity

Journal of Experimental Medicine ◽

10.1084/jem.20180246 ◽

2018 ◽

Vol 215 (6) ◽

pp. 1589-1608 ◽

Cited By ~ 17

Author(s):

Claus Kadelka ◽

Thomas Liechti ◽

Hanna Ebner ◽

Merle Schanz ◽

Peter Rusert ◽

...

Keyword(s):

Vaccine Development ◽

Neutralizing Antibody ◽

Antibody Responses ◽

Igg Subclass ◽

Dependent Manner ◽

Immune Modulators ◽

Broadly Neutralizing Antibody ◽

Binding Antibody ◽

Hiv 1 ◽

Disease Parameters

Understanding pathways that promote HIV-1 broadly neutralizing antibody (bnAb) induction is crucial to advance bnAb-based vaccines. We recently demarcated host, viral, and disease parameters associated with bnAb development in a large HIV-1 cohort screen. By establishing comprehensive antibody signatures based on IgG1, IgG2, and IgG3 activity to 13 HIV-1 antigens in 4,281 individuals in the same cohort, we now show that the same four parameters that are significantly linked with neutralization breadth, namely viral load, infection length, viral diversity, and ethnicity, also strongly influence HIV-1–binding antibody responses. However, the effects proved selective, shaping binding antibody responses in an antigen and IgG subclass–dependent manner. IgG response landscapes in bnAb inducers indicated a differentially regulated, IgG1-driven HIV-1 antigen response, and IgG1 binding of the BG505 SOSIP trimer proved the best predictor of HIV-1 neutralization breadth in plasma. Our findings emphasize the need to unravel immune modulators that underlie the differentially regulated IgG response in bnAb inducers to guide vaccine development.

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Ultrastructural observations of human monocytes infected with HIV-1

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084843 ◽

1991 ◽

Vol 49 ◽

pp. 108-109

Author(s):

James K. Koehler ◽

Steven G. Reed ◽

Joao S. Silva

Keyword(s):

Gradient Centrifugation ◽

Virus Production ◽

Human Monocyte ◽

Red Cross ◽

Human Monocytes ◽

Blood Monocytes ◽

Hiv Replication ◽

Electron Microscopic ◽

Ultrastructural Studies ◽

Hiv 1

As part of a larger study involving the co-infection of human monocyte cultures with HIV and protozoan parasites, electron microscopic observations were made on the course of HIV replication and infection in these cells. Although several ultrastructural studies of the cytopathology associated with HIV infection have appeared, few studies have shown the details of virus production in “normal,” human monocytes/macrophages, one of the natural targets of the virus, and suspected of being a locus of quiescent virus during its long latent period. In this report, we detail some of the interactions of developing virons with the membranes and organelles of the monocyte host.Peripheral blood monocytes were prepared from buffy coats (Portland Red Cross) by Percoll gradient centrifugation, followed by adherence to cover slips. 90-95% pure monocytes were cultured in RPMI with 5% non-activated human AB serum for four days and infected with 100 TCID50/ml of HIV-1 for four hours, washed and incubated in fresh medium for 14 days.

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