HIV-1 Cell to Cell Transfer across an Env-induced, Actin-dependent Synapse

Direct cell–cell transfer is an efficient mechanism of viral dissemination within an infected host, and human immunodeficiency virus 1 (HIV-1) can exploit this mode of spread. Receptor recognition by HIV-1 occurs via interactions between the viral surface envelope glycoprotein (Env), gp120, and CD4 and a chemokine receptor, CCR5 or CXCR4. Here, we demonstrate that the binding of CXCR4-using HIV-1–infected effector T cells to primary CD4+/CXCR4+ target T cells results in rapid recruitment to the interface of CD4, CXCR4, talin, and lymphocyte function–associated antigen 1 on the target cell, and of Env and Gag on the effector cell. Recruitment of these membrane molecules into polarized clusters was dependent on Env engagement of CD4 and CXCR4 and required remodelling of the actin cytoskeleton. Transfer of Gag from effector to target cell was observed by 1 h after conjugate formation, was independent of cell–cell fusion, and was probably mediated by directed virion fusion with the target cell. We propose that receptor engagement by Env directs the rapid, actin-dependent recruitment of HIV receptors and adhesion molecules to the interface, resulting in a stable adhesive junction across which HIV infects the target cell.

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Cell-Cell Spread of Human Immunodeficiency Virus Type 1 Overcomes Tetherin/BST-2-Mediated Restriction in T cells

Journal of Virology ◽

10.1128/jvi.01447-10 ◽

2010 ◽

Vol 84 (23) ◽

pp. 12185-12199 ◽

Cited By ~ 122

Author(s):

Clare Jolly ◽

Nicola J. Booth ◽

Stuart J. D. Neil

Keyword(s):

Human Immunodeficiency Virus ◽

T Cells ◽

Cell Surface ◽

Cell Transfer ◽

Free Virion ◽

Immunodeficiency Virus ◽

Cell To Cell Transfer ◽

Cell Spread ◽

Hiv 1

ABSTRACT Direct cell-to-cell spread of human immunodeficiency virus type 1 (HIV-1) between T cells at the virological synapse (VS) is an efficient mechanism of viral dissemination. Tetherin (BST-2/CD317) is an interferon-induced, antiretroviral restriction factor that inhibits nascent cell-free particle release. The HIV-1 Vpu protein antagonizes tetherin activity; however, whether tetherin also restricts cell-cell spread is unclear. We performed quantitative cell-to-cell transfer analysis of wild-type (WT) or Vpu-defective HIV-1 in Jurkat and primary CD4+ T cells, both of which express endogenous levels of tetherin. We found that Vpu-defective HIV-1 appeared to disseminate more efficiently by cell-to-cell contact between Jurkat cells under conditions where tetherin restricted cell-free virion release. In T cells infected with Vpu-defective HIV-1, tetherin was enriched at the VS, and VS formation was increased compared to the WT, correlating with an accumulation of virus envelope proteins on the cell surface. Increasing tetherin expression with type I interferon had only minor effects on cell-to-cell transmission. Furthermore, small interfering RNA (siRNA)-mediated depletion of tetherin decreased VS formation and cell-to-cell transmission of both Vpu-defective and WT HIV-1. Taken together, these data demonstrate that tetherin does not restrict VS-mediated T cell-to-T cell transfer of Vpu-defective HIV-1 and suggest that under some circumstances tetherin might promote cell-to-cell transfer, either by mediating the accumulation of virions on the cell surface or by regulating integrity of the VS. If so, inhibition of tetherin activity by Vpu may balance requirements for efficient cell-free virion production and cell-to-cell transfer of HIV-1 in the face of antiviral immune responses.

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Manipulating CD4+T cells by optical tweezers for the initiation of cell-cell transfer of HIV-1

Journal of Biophotonics ◽

10.1002/jbio.200900102 ◽

2010 ◽

Vol 3 (4) ◽

pp. 216-223 ◽

Cited By ~ 19

Author(s):

Gregory P. McNerney ◽

Wolfgang Hübner ◽

Benjamin K. Chen ◽

Thomas Huser

Keyword(s):

T Cells ◽

Optical Tweezers ◽

Cd4 T Cells ◽

Cell Transfer ◽

Hiv 1 ◽

Cell Cell

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Macrophage Cell-Cell Interactions Promoting HIV-1 Infection

Viruses ◽

10.3390/v12050492 ◽

2020 ◽

Vol 12 (5) ◽

pp. 492 ◽

Cited By ~ 1

Author(s):

Maeva Dupont ◽

Quentin James Sattentau

Keyword(s):

T Cells ◽

Viral Entry ◽

Macrophage Infection ◽

Macrophage Cell ◽

Current State ◽

Direct Cell ◽

Cell Spread ◽

Hiv 1 ◽

Cell Cell

Many pathogens infect macrophages as part of their intracellular life cycle. This is particularly true for viruses, of which HIV-1 is one of the best studied. HIV-1 infection of macrophages has important consequences for viral persistence and pathogenesis, but the mechanisms of macrophage infection remain to be fully elucidated. Despite expressing viral entry receptors, macrophages are inefficiently infected by cell-free HIV-1 virions, whereas direct cell-cell spread is more efficient. Different modes of cell-cell spread have been described, including the uptake by macrophages of infected T cells and the fusion of infected T cells with macrophages, both leading to macrophage infection. Cell-cell spread can also transmit HIV-1 between macrophages and from macrophages to T cells. Here, we describe the current state of the field concerning the cell-cell spread of HIV-1 to and from macrophages, discuss mechanisms, and highlight potential in vivo relevance.

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T Cell-Macrophage Fusion Triggers Multinucleated Giant Cell Formation for HIV-1 Spreading

Journal of Virology ◽

10.1128/jvi.01237-17 ◽

2017 ◽

Vol 91 (24) ◽

Cited By ~ 31

Author(s):

Lucie Bracq ◽

Maorong Xie ◽

Marie Lambelé ◽

Lan-Trang Vu ◽

Julie Matz ◽

...

Keyword(s):

T Cells ◽

Cell Fusion ◽

Giant Cells ◽

Cell Transfer ◽

Multinucleated Giant Cells ◽

Virus Dissemination ◽

Virus Spreading ◽

Cell To Cell Transfer ◽

Hiv 1 ◽

Host Tissues

ABSTRACT HIV-1-infected macrophages participate in virus dissemination and establishment of virus reservoirs in host tissues, but the mechanisms for virus cell-to-cell transfer to macrophages remain unknown. Here, we reveal the mechanisms for cell-to-cell transfer from infected T cells to macrophages and virus spreading between macrophages. We show that contacts between infected T lymphocytes and macrophages lead to cell fusion for the fast and massive transfer of CCR5-tropic viruses to macrophages. Through the merge of viral material between T cells and macrophages, these newly formed lymphocyte-macrophage fused cells acquire the ability to fuse with neighboring noninfected macrophages. Together, these two-step envelope-dependent cell fusion processes lead to the formation of highly virus-productive multinucleated giant cells reminiscent of the infected multinucleated giant macrophages detected in HIV-1-infected patients and simian immunodeficiency virus-infected macaques. These mechanisms represent an original mode of virus transmission for viral spreading and a new model for the formation of macrophage virus reservoirs during infection. IMPORTANCE We reveal a very efficient mechanism involved in cell-to-cell transfer from infected T cells to macrophages and subsequent virus spreading between macrophages by a two-step cell fusion process. Infected T cells first establish contacts and fuse with macrophage targets. The newly formed lymphocyte-macrophage fused cells then acquire the ability to fuse with surrounding uninfected macrophages, leading to the formation of infected multinucleated giant cells that can survive for a long time, as evidenced in vivo in lymphoid organs and the central nervous system. This route of infection may be a major determinant for virus dissemination and the formation of macrophage virus reservoirs in host tissues during HIV-1 infection.

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Requirement for an Intact T-Cell Actin and Tubulin Cytoskeleton for Efficient Assembly and Spread of Human Immunodeficiency Virus Type 1

Journal of Virology ◽

10.1128/jvi.01469-06 ◽

2007 ◽

Vol 81 (11) ◽

pp. 5547-5560 ◽

Cited By ~ 134

Author(s):

Clare Jolly ◽

Ivonne Mitar ◽

Quentin J. Sattentau

Keyword(s):

Human Immunodeficiency Virus ◽

T Cells ◽

Plasma Membrane ◽

T Cell ◽

Immunodeficiency Virus ◽

Fixed Cell ◽

Cell Spread ◽

Hiv 1 ◽

Cell Cell

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) infection of CD4+ T cells leads to the production of new virions that assemble at the plasma membrane. Gag and Env accumulate in the context of lipid rafts at the inner and outer leaflets of the plasma membrane, respectively, forming polarized domains from which HIV-1 buds. HIV-1 budding can result in either release of cell-free virions or direct cell-cell spread via a virological synapse (VS). The recruitment of Gag and Env to these plasma membrane caps in T cells is poorly understood but may require elements of the T-cell secretory apparatus coordinated by the cytoskeleton. Using fixed-cell immunofluorescence labeling and confocal microscopy, we observed a high percentage of HIV-1-infected T cells with polarized Env and Gag in capped, lipid raft-like assembly domains. Treatment of infected T cells with inhibitors of actin or tubulin remodeling disrupted Gag and Env compartmentalization within the polarized raft-like domains. Depolymerization of the actin cytoskeleton reduced Gag release and viral infectivity, and actin and tubulin inhibitors reduced Env incorporation into virions. Live- and fixed-cell confocal imaging and assay of de novo DNA synthesis by real-time PCR allowed quantification of HIV-1 cell-cell transfer. Inhibition of actin and tubulin remodeling in infected cells interfered with cell-cell spread across a VS and reduced new viral DNA synthesis. Based on these data, we propose that HIV-1 requires both actin and tubulin components of the T-cell cytoskeleton to direct its assembly and budding and to elaborate a functional VS.

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Distinct efficacy of HIV-1 entry inhibitors to prevent cell-to-cell transfer of R5 and X4 viruses across a human placental trophoblast barrier in a reconstitution model in vitro

Retrovirology ◽

10.1186/1742-4690-5-31 ◽

2008 ◽

Vol 5 (1) ◽

pp. 31 ◽

Cited By ~ 7

Author(s):

Ahidjo Ayouba ◽

Claude Cannou ◽

Marie-Thérèse Nugeyre ◽

Françoise Barré-Sinoussi ◽

Elisabeth Menu

Keyword(s):

Cell Transfer ◽

Entry Inhibitors ◽

Cell To Cell Transfer ◽

Hiv 1

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The envelope cytoplasmic tail regulates HIV-1 assembly and spread

10.1101/2021.02.08.430194 ◽

2021 ◽

Author(s):

Xenia Snetkov ◽

Tafhima Haider ◽

Dejan Mesner ◽

Nicholas Groves ◽

Schuyler van Engelenburg ◽

...

Keyword(s):

T Cells ◽

Structural Integrity ◽

Alpha Helix ◽

Cytoplasmic Tail ◽

Virological Synapse ◽

Cell Contact ◽

Viral Fusion ◽

And Function ◽

Hiv 1 ◽

Cell Cell

AbstractThe HIV-1 envelope (Env) is an essential determinant of viral infectivity, tropism and spread between T cells. Lentiviral Env contain an unusually long 150 amino acid cytoplasmic tail (EnvCT) but the function of the EnvCT and conserved domains within it remain largely uncharacterised. Here we identified a highly conserved tryptophan motif at position 757 (W757) in the LLP-2 alpha helix of the EnvCT as a key determinant for HIV-1 replication and spread between T cells. Strikingly we find that mutating W757 had wide-ranging consequences including altering Env mobility in the plasma membrane, preventing Env and Gag recruitment to sites of cell-cell contact for virological synapse (VS) formation and cell-cell spread, and impeding viral fusion. Notably, W757 was also required for efficient virus budding, revealing a previously unappreciated role for the EnvCT in regulating HIV-1 assembly and egress. We conclude that W757 is a key residue that stabilises the structural integrity and function of Env, consistent with the recent model that this region of the EnvCT acts as a critical supporting baseplate for Env.

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A Conserved Tryptophan in the Envelope Cytoplasmic Tail Regulates HIV-1 Assembly and Spread

Viruses ◽

10.3390/v14010129 ◽

2022 ◽

Vol 14 (1) ◽

pp. 129

Author(s):

Xenia Snetkov ◽

Tafhima Haider ◽

Dejan Mesner ◽

Nicholas Groves ◽

Schuyler B. van Engelenburg ◽

...

Keyword(s):

T Cells ◽

Single Molecule ◽

Virus Assembly ◽

Alpha Helix ◽

Cytoplasmic Tail ◽

Virological Synapse ◽

Cell Contact ◽

Viral Spread ◽

Hiv 1 ◽

Cell Cell

The HIV-1 envelope (Env) is an essential determinant of viral infectivity, tropism and spread between T cells. Lentiviral Env contain an unusually long 150 amino acid cytoplasmic tail (EnvCT), but the function of the EnvCT and many conserved domains within it remain largely uncharacterised. Here, we identified a highly conserved tryptophan motif at position 757 (W757) in the LLP-2 alpha helix of the EnvCT as a key determinant for HIV-1 replication and spread between T cells. Alanine substitution at this position potently inhibited HIV-1 cell–cell spread (the dominant mode of HIV-1 dissemination) by preventing recruitment of Env and Gag to sites of cell–cell contact, inhibiting virological synapse (VS) formation and spreading infection. Single-molecule tracking and super-resolution imaging showed that mutation of W757 dysregulates Env diffusion in the plasma membrane and increases Env mobility. Further analysis of Env function revealed that W757 is also required for Env fusion and infectivity, which together with reduced VS formation, result in a potent defect in viral spread. Notably, W757 lies within a region of the EnvCT recently shown to act as a supporting baseplate for Env. Our data support a model in which W757 plays a key role in regulating Env biology, modulating its temporal and spatial recruitment to virus assembly sites and regulating the inherent fusogenicity of the Env ectodomain, thereby supporting efficient HIV-1 replication and spread.

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Tuberculosis-associated IFN-I induces Siglec-1 on tunneling nanotubes and favors HIV-1 spread in macrophages

eLife ◽

10.7554/elife.52535 ◽

2020 ◽

Vol 9 ◽

Cited By ~ 6

Author(s):

Maeva Dupont ◽

Shanti Souriant ◽

Luciana Balboa ◽

Thien-Phong Vu Manh ◽

Karine Pingris ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Risk Factor ◽

Type I Interferon ◽

Type I ◽

Cell Transfer ◽

Tunneling Nanotubes ◽

Factors Associated ◽

Tunneling Nanotube ◽

Cell To Cell Transfer ◽

Hiv 1

While tuberculosis (TB) is a risk factor in HIV-1-infected individuals, the mechanisms by which Mycobacterium tuberculosis (Mtb) worsens HIV-1 pathogenesis remain scarce. We showed that HIV-1 infection is exacerbated in macrophages exposed to TB-associated microenvironments due to tunneling nanotube (TNT) formation. To identify molecular factors associated with TNT function, we performed a transcriptomic analysis in these macrophages, and revealed the up-regulation of Siglec-1 receptor. Siglec-1 expression depends on Mtb-induced production of type I interferon (IFN-I). In co-infected non-human primates, Siglec-1 is highly expressed by alveolar macrophages, whose abundance correlates with pathology and activation of IFN-I/STAT1 pathway. Siglec-1 localizes mainly on microtubule-containing TNT that are long and carry HIV-1 cargo. Siglec-1 depletion decreases TNT length, diminishes HIV-1 capture and cell-to-cell transfer, and abrogates the exacerbation of HIV-1 infection induced by Mtb. Altogether, we uncover a deleterious role for Siglec-1 in TB-HIV-1 co-infection and open new avenues to understand TNT biology.

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