scholarly journals HIV-1 Envelope Glycoprotein Trafficking and Viral Transmission

Proceedings ◽  
2020 ◽  
Vol 50 (1) ◽  
pp. 17
Author(s):  
Melissa Victoria Fernandez ◽  
Lwar N Naing ◽  
David A Scheiblin ◽  
Sherimay D Ablan ◽  
Jennifer A Simmons ◽  
...  
Keyword(s):  
T Cell ◽  
Envelope Glycoprotein ◽  
Viral Transmission ◽  
Virological Synapse ◽  
Glycoprotein Complex ◽  
Viral Spread ◽  
Clade B ◽  
Clade C ◽  
T Cell Lines ◽  
Hiv 1

HIV-1 encodes an envelope glycoprotein complex (Env) containing a long cytoplasmic tail (CT) harboring trafficking motifs implicated in Env incorporation into virions. Although the requirement for the Env CT in viral transmission is known, the precise mechanism by which Env is incorporated into nascent virions and localizes to the virological synapse remains poorly defined. To further elucidate the mechanism of Env trafficking, we examined three HIV-1 strains: the lab-adapted clade B strain, NL4-3, and a transmitted/founder (T/F) clade C virus, K3016, and a T/F clade B virus, CH077. The HIV-1 Env CT contains two invariant trafficking motifs: tyrosine endocytosis motif, Y712SPL, and C-terminal dileucine motif, LL855. Virion Env incorporation analysis revealed that Y712SPL is necessary for efficient Env incorporation, while LL855 is dispensable. Spreading infection kinetics were analyzed in various T-cell lines and primary human PBMCs; the results indicated that both endocytic motifs contribute to efficient viral spread in culture. Analysis of Env localization to the T-cell uropod, the portion of the plasma membrane that forms a virological synapse with uninfected cells, was found to be dependent on the Env CT and the Y712SPL motif. Cell-to-cell and cell-free transmission assays using T cells infected with HIV-1 bearing Y712A or LL855AA Env CT mutations are ongoing to establish a role for these motifs in both modes of viral transmission. These studies will significantly enhance our understanding of Env trafficking and viral transmission, providing insights into viral Env–host interactions in physiologically relevant cells.

scholarly journals Elucidating the basis for permissivity of the MT-4 T-cell line to replication of an HIV-1 mutant lacking the gp41 cytoplasmic tail

2020 ◽  
Author(s):  
Melissa V. Fernandez ◽  
Huxley K. Hoffman ◽  
Nairi Pezeshkian ◽  
Philip R. Tedbury ◽  
Schuyler B. van Engelenburg ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Line ◽  
Cell Lines ◽  
Cytoplasmic Tail ◽  
Viral Transmission ◽  
Virus Particles ◽  
Cell Transmission ◽  
T Cell Lines ◽  
Hiv 1

AbstractHIV-1 encodes an envelope glycoprotein (Env) that contains a long cytoplasmic tail (CT) harboring trafficking motifs implicated in Env incorporation into virus particles and viral transmission. In most physiologically relevant cell types, the gp41 CT is required for HIV-1 replication, but in the MT-4 T-cell line the gp41 CT is not required for a spreading infection. To help elucidate the role of the gp41 CT in HIV-1 transmission, in this study we investigated the viral and cellular factors that contribute to the permissivity of MT-4 to gp41 CT truncation. We found that the kinetics of HIV-1 production are faster in MT-4 than in the other T-cell lines tested, but MT-4 express equivalent amounts of HIV-1 proteins on a per-cell basis relative to cells not permissive to CT truncation. MT-4 express higher levels of plasma-membrane-associated Env than non-permissive cells and Env internalization from the plasma membrane is slower compared to another T-cell line, SupT1. Paradoxically, despite the high levels of Env on the surface of MT-4, two-fold less Env is incorporated into virus particles in MT-4 compared to SupT1. Cell-to-cell transmission between co-cultured 293T and MT-4 is higher than in co-cultures of 293T with most other T-cell lines tested, indicating that MT-4 are highly susceptible to this mode of infection. These data help to clarify the long-standing question of how MT-4 cells overcome the requirement for the HIV-1 gp41 CT and support a role for gp41 CT-dependent trafficking in Env incorporation and cell-to-cell transmission in physiologically relevant cell lines.ImportanceThe HIV-1 Env cytoplasmic tail (CT) is required for efficient Env incorporation into nascent particles and viral transmission in primary CD4+ T cells. The MT-4 T-cell line has been reported to support multiple rounds of infection of HIV-1 encoding a gp41 CT truncation. Uncovering the underlying mechanism of MT-4 T-cell line permissivity to gp41 CT truncation would provide key insights into the role of the gp41 CT in HIV-1 transmission. This study reveals that multiple factors contribute to the unique ability of a gp41 CT truncation mutant to spread in cultures of MT-4 cells. The lack of a requirement for the gp41 CT in MT-4 is associated with the combined effects of rapid HIV-1 protein production, high levels of cell-surface Env expression, and increased susceptibility to cell-to-cell transmission compared to non-permissive cells.

scholarly journals Elucidating the Basis for Permissivity of the MT-4 T-Cell Line to Replication of an HIV-1 Mutant Lacking the gp41 Cytoplasmic Tail

2020 ◽  
Vol 94 (23) ◽  
Author(s):  
Melissa V. Fernandez ◽  
Huxley K. Hoffman ◽  
Nairi Pezeshkian ◽  
Philip R. Tedbury ◽  
Schuyler B. van Engelenburg ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
T Cell ◽  
Cell Line ◽  
Cell Lines ◽  
Cytoplasmic Tail ◽  
Viral Transmission ◽  
Virus Particles ◽  
T Cell Lines ◽  
Hiv 1

ABSTRACT HIV-1 encodes an envelope glycoprotein (Env) that contains a long cytoplasmic tail (CT) harboring trafficking motifs implicated in Env incorporation into virus particles and viral transmission. In most physiologically relevant cell types, the gp41 CT is required for HIV-1 replication, but in the MT-4 T-cell line the gp41 CT is not required for a spreading infection. To help elucidate the role of the gp41 CT in HIV-1 transmission, in this study, we investigated the viral and cellular factors that contribute to the permissivity of MT-4 cells to gp41 CT truncation. We found that the kinetics of HIV-1 production and virus release are faster in MT-4 than in the other T-cell lines tested, but MT-4 cells express equivalent amounts of HIV-1 proteins on a per-cell basis relative to cells not permissive to CT truncation. MT-4 cells express higher levels of plasma-membrane-associated Env than nonpermissive cells, and Env internalization from the plasma membrane is less efficient than that from another T-cell line, SupT1. Paradoxically, despite the high levels of Env on the surface of MT-4 cells, 2-fold less Env is incorporated into virus particles produced from MT-4 than SupT1 cells. Contact-dependent transmission between cocultured 293T and MT-4 cells is higher than in cocultures of 293T with most other T-cell lines tested, indicating that MT-4 cells are highly susceptible to cell-to-cell infection. These data help to clarify the long-standing question of how MT-4 cells overcome the requirement for the HIV-1 gp41 CT and support a role for gp41 CT-dependent trafficking in Env incorporation and cell-to-cell transmission in physiologically relevant cell lines. IMPORTANCE The HIV-1 Env cytoplasmic tail (CT) is required for efficient Env incorporation into nascent particles and viral transmission in primary CD4+ T cells. The MT-4 T-cell line has been reported to support multiple rounds of infection of HIV-1 encoding a gp41 CT truncation. Uncovering the underlying mechanism of MT-4 T-cell line permissivity to gp41 CT truncation would provide key insights into the role of the gp41 CT in HIV-1 transmission. This study reveals that multiple factors contribute to the unique ability of a gp41 CT truncation mutant to spread in cultures of MT-4 cells. The lack of a requirement for the gp41 CT in MT-4 cells is associated with the combined effects of rapid HIV-1 protein production, high levels of cell-surface Env expression, and increased susceptibility to cell-to-cell transmission compared to nonpermissive cells.

Polyfunctional CD8+ T-Cell Response to Autologous Peptides from Protease and Reverse Transcriptase of HIV-1 Clade B

2019 ◽  
Vol 17 (5) ◽  
pp. 350-359
Author(s):  
Liliana Acevedo-Saenz ◽  
Federico Perdomo-Celis ◽  
Carlos J. Montoya ◽  
Paula A. Velilla
Keyword(s):  
T Cell ◽  
Reverse Transcriptase ◽  
Cellular Response ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Effective Vaccine ◽  
Cell Responses ◽  
Clade B ◽  
Hiv 1

Background: : The diversity of the HIV proteome influences the cellular response and development of an effective vaccine, particularly due to the generation of viral variants with mutations located within CD8+ T-cell epitopes. These mutations can affect the recognition of the epitopes, that may result in the selection of HIV variants with mutated epitopes (autologous epitopes) and different CD8+ T-cell functional profiles. Objective:: To determine the phenotype and functionality of CD8+ T-cell from HIV-infected Colombian patients in response to autologous and consensus peptides derived from HIV-1 clade B protease and reverse transcriptase (RT). Methods:: By flow cytometry, we compared the ex vivo CD8+ T-cell responses from HIV-infected patients to autologous and consensus peptides derived from HIV-1 clade B protease and RT, restricted by HLA-B*35, HLA-B*44 and HLA-B*51 alleles. Results:: Although autologous peptides restricted by HLA-B*35 and HLA-B*44 did not show any differences compared with consensus peptides, we observed the induction of a higher polyfunctional profile of CD8+ T-cells by autologous peptides restricted by HLA-B*51, particularly by the production of interferon-γ and macrophage inflammatory protein-1β. The response by different memory CD8+ T-cell populations was comparable between autologous vs. consensus peptides. In addition, the magnitude of the polyfunctional response induced by the HLA-B*51-restricted QRPLVTIRI autologous epitope correlated with low viremia. Conclusion:: Autologous peptides should be considered for the evaluation of HIV-specific CD8+ Tcell responses and to reveal some relevant epitopes that could be useful for therapeutic strategies aiming to promote polyfunctional CD8+ T-cell responses in a specific population of HIV-infected patients.

scholarly journals Antagonism to and Intracellular Sequestration of Human Tetherin by the Human Immunodeficiency Virus Type 2 Envelope Glycoprotein

2009 ◽  
Vol 83 (22) ◽  
pp. 11966-11978 ◽  
Author(s):  
Anna Le Tortorec ◽  
Stuart J. D. Neil
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Envelope Glycoprotein ◽  
Virus Assembly ◽  
Accessory Gene ◽  
Immunodeficiency Virus ◽  
T Cell Lines ◽  
Hiv 1 ◽  
Tetherin Antagonism

ABSTRACT Tetherin (CD317/BST-2), an interferon-induced membrane protein, restricts the release of nascent retroviral particles from infected cell surfaces. While human immunodeficiency virus type 1 (HIV-1) encodes the accessory gene vpu to overcome the action of tetherin, the lineage of primate lentiviruses that gave rise to HIV-2 does not. It has been previously reported that the HIV-2 envelope glycoprotein has a Vpu-like function in promoting virus release. Here we demonstrate that the HIV-2 Rod envelope glycoprotein (HIV-2 Rod Env) is a tetherin antagonist. Expression of HIV-2 Rod Env, but not that of HIV-1 or the closely related simian immunodeficiency virus (SIV) SIVmac1A11, counteracts tetherin-mediated restriction of Vpu-defective HIV-1 in a cell-type-specific manner. This correlates with the ability of the HIV-2 Rod Env to mediate cell surface downregulation of tetherin. Antagonism requires an endocytic motif conserved across HIV/SIV lineages in the gp41 cytoplasmic tail, but specificity for tetherin is governed by extracellular determinants in the mature Env protein. Coimmunoprecipitation studies suggest an interaction between HIV-2 Rod Env and tetherin, but unlike studies with Vpu, we found no evidence of tetherin degradation. In the presence of HIV-2 Rod Env, tetherin localization is restricted to the trans-Golgi network, suggesting Env-mediated effects on tetherin trafficking sequester it from virus assembly sites on the plasma membrane. Finally, we recapitulated these observations in HIV-2-infected CD4+ T-cell lines, demonstrating that tetherin antagonism and sequestration occur at physiological levels of Env expression during virus replication.

Cost-Effective High-Speed, Three-Dimensional Live-Cell Imaging of HIV-1 Transfer at the T Cell Virological Synapse

2021 ◽  
Author(s):  
Alice Sandmeyer ◽  
Lili Wang ◽  
Wolfgang Hübner ◽  
Marcel Müller ◽  
Benjamin Chen ◽  
...  
Keyword(s):  
T Cell ◽  
Live Cell Imaging ◽  
High Speed ◽  
Cell Imaging ◽  
Three Dimensional ◽  
Cost Effective ◽  
Live Cell ◽  
Virological Synapse ◽  
Hiv 1

scholarly journals High-Multiplicity HIV-1 Infection and Neutralizing Antibody Evasion Mediated by the Macrophage-T Cell Virological Synapse

2013 ◽  
Vol 88 (4) ◽  
pp. 2025-2034 ◽  
Author(s):  
C. J. A. Duncan ◽  
J. P. Williams ◽  
T. Schiffner ◽  
K. Gartner ◽  
C. Ochsenbauer ◽  
...  
Keyword(s):  
T Cell ◽  
Neutralizing Antibody ◽  
High Multiplicity ◽  
Virological Synapse ◽  
Hiv 1

Cell-Surface Heparan Sulfate Proteoglycan Mediates HIV-1 Infection of T-Cell Lines

1993 ◽  
Vol 9 (2) ◽  
pp. 167-174 ◽  
Author(s):  
MAHESH PATEL ◽  
MASAKI YANAGISHITA ◽  
GREGORY RODERIQUEZ ◽  
DUMITH CHEQUER BOU-HABIB ◽  
TAMAS ORAVECZ ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Surface ◽  
Heparan Sulfate ◽  
Cell Lines ◽  
Heparan Sulfate Proteoglycan ◽  
Sulfate Proteoglycan ◽  
T Cell Lines ◽  
Hiv 1

scholarly journals Immune correlates of the Thai RV144 HIV vaccine regimen in South Africa

2019 ◽  
Vol 11 (510) ◽  
pp. eaax1880 ◽  
Author(s):  
Glenda E. Gray ◽  
Ying Huang ◽  
Nicole Grunenberg ◽  
Fatima Laher ◽  
Surita Roux ◽  
...  
Keyword(s):  
South Africa ◽  
T Cell ◽  
Immune Responses ◽  
Hiv Vaccine ◽  
Antibody Responses ◽  
Vaccine Regimen ◽  
Humoral Immune ◽  
Immune Correlates ◽  
Clade C ◽  
Hiv 1

One of the most successful HIV vaccines to date, the RV144 vaccine tested in Thailand, demonstrated correlates of protection including cross-clade V1V2 immunoglobulin G (IgG) breadth, Env-specific CD4+ T cell polyfunctionality, and antibody-dependent cellular cytotoxicity (ADCC) in vaccinees with low IgA binding. The HIV Vaccine Trials Network (HVTN) 097 trial evaluated this vaccine regimen in South Africa, where clade C HIV-1 predominates. We compared cellular and humoral responses at peak and durability immunogenicity time points in HVTN 097 and RV144 vaccinee samples, and evaluated vaccine-matched and cross-clade immune responses. At peak immunogenicity, HVTN 097 vaccinees exhibited significantly higher cellular and humoral immune responses than RV144 vaccinees. CD4+ T cell responses were more frequent in HVTN 097 irrespective of age and sex, and CD4+ T cell Env-specific functionality scores were higher in HVTN 097. Env-specific CD40L+ CD4+ T cells were more common in HVTN 097, with individuals having this pattern of expression demonstrating higher median antibody responses to HIV-1 Env. IgG and IgG3 binding antibody rates and response magnitude to gp120 vaccine– and V1V2 vaccine–matched antigens were higher or comparable in HVTN 097 than in RV144 ADCC, and ADCP functional antibody responses were elicited in HVTN 097. Env-specific IgG and CD4+ Env responses declined significantly over time in both trials. Overall, cross-clade immune responses associated with protection were better than expected in South Africa, suggesting wider applicability of this regimen.

scholarly journals Griffithsin Retains Anti-HIV-1 Potency with Changes in gp120 Glycosylation and Complements Broadly Neutralizing Antibodies PGT121 and PGT126

2019 ◽  
Vol 64 (1) ◽  
Author(s):  
Kathryn Fischer ◽  
Kimberly Nguyen ◽  
Patricia J. LiWang
Keyword(s):  
Neutralizing Antibodies ◽  
Glycosylation Site ◽  
Significant Loss ◽  
Broadly Neutralizing Antibodies ◽  
Clade B ◽  
Key Factor ◽  
Clade C ◽  
Cd4 Binding Site ◽  
Gp120 Glycosylation ◽  
Hiv 1

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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