scholarly journals Nef-Induced CD4 Endocytosis in Human Immunodeficiency Virus Type 1 Host Cells: Role of p56lck Kinase

2009 ◽  
Vol 83 (14) ◽  
pp. 7117-7128 ◽  
Author(s):  
Nadine Laguette ◽  
Christelle Brégnard ◽  
Jérôme Bouchet ◽  
Alexandre Benmerah ◽  
Serge Benichou ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cell Surface ◽  
Surface Expression ◽  
Lymphoid Cells ◽  
Cell Surface Expression ◽  
Target Cells ◽  
Immunodeficiency Virus ◽  
Internalization Rate ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) Nef interferes with the endocytic machinery to modulate the cell surface expression of CD4. However, the basal trafficking of CD4 is governed by different rules in the target cells of HIV-1: whereas CD4 is rapidly internalized from the cell surface in myeloid cells, CD4 is stabilized at the plasma membrane through its interaction with the p56 lck kinase in lymphoid cells. In this study, we showed that Nef was able to downregulate CD4 in both lymphoid and myeloid cell lines but that an increase in the internalization rate of CD4 could be observed only in lymphoid cells. Expression of p56 lck in nonlymphoid CD4-expressing cells restores the ability of Nef in order to increase the internalization rate of CD4. Concurrent with this observation, the expression of a p56 lck -binding-deficient mutant of CD4 in lymphoid cells abrogates the Nef-induced acceleration of CD4 internalization. We also show that the expression of Nef causes a decrease in the association of p56 lck with cell surface-expressed CD4. Regardless of the presence of p56 lck , the downregulation of CD4 by Nef was followed by CD4 degradation. Our results imply that Nef uses distinct mechanisms to downregulate the cell surface expression levels of CD4 in either lymphoid or myeloid target cells of HIV-1.

scholarly journals Effect of Calcium-Modulating Cyclophilin Ligand on Human Immunodeficiency Virus Type 1 Particle Release and Cell Surface Expression of Tetherin

2009 ◽  
Vol 83 (24) ◽  
pp. 13032-13036 ◽  
Author(s):  
Mariana G. Bego ◽  
Mathieu Dubé ◽  
Johanne Mercier ◽  
Éric A. Cohen
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cell Surface ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Particle Release ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The human immunodeficiency virus type 1 (HIV-1) accessory protein Vpu enhances virus particle release by counteracting a host factor that retains virions at the surfaces of infected cells. It was recently demonstrated that cellular protein BST-2/CD317/Tetherin restricts HIV-1 release in a Vpu-dependent manner. Calcium-modulating cyclophilin ligand (CAML) was also proposed to be involved in this process. We investigated whether CAML is involved in cell surface expression of Tetherin. Here, we show that CAML overexpression in permissive Cos-7 cells or CAML depletion in restrictive HeLa cells has no effect on HIV-1 release or on Tetherin surface expression, indicating that CAML is not required for Tetherin-mediated restriction of HIV-1 release.

scholarly journals DC-SIGN Interactions with Human Immunodeficiency Virus Type 1 and 2 and Simian Immunodeficiency Virus

2001 ◽  
Vol 75 (10) ◽  
pp. 4664-4672 ◽  
Author(s):  
Stefan Pöhlmann ◽  
Frédéric Baribaud ◽  
Benhur Lee ◽  
George J. Leslie ◽  
Melissa D. Sanchez ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cell Surface ◽  
Lectin Binding ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Virus Binding ◽  
Expression Levels ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Dendritic cells (DCs) efficiently bind and transmit human immunodeficiency virus (HIV) to cocultured T cells and so may play an important role in HIV transmission. DC-SIGN, a novel C-type lectin that is expressed in DCs, has recently been shown to bind R5 HIV type 1 (HIV-1) strains and a laboratory-adapted X4 strain. To characterize the interaction of DC-SIGN with primate lentiviruses, we investigated the structural determinants of DC-SIGN required for virus binding and transmission to permissive cells. We constructed a panel of DC-SIGN mutants and established conditions which allowed comparable cell surface expression of all mutants. We found that R5, X4, and R5X4 HIV-1 isolates as well as simian immunodeficiency and HIV-2 strains bound to DC-SIGN and could be transmitted to CD4/coreceptor-positive cell types. DC-SIGN contains a single N-linked carbohydrate chain that is important for efficient cell surface expression but is not required for DC-SIGN-mediated virus binding and transmission. In contrast, C-terminal deletions removing either the lectin binding domain or the repeat region abrogated DC-SIGN function. Trypsin-EDTA treatment inhibited DC-SIGN mediated infection, indicating that virus was maintained at the surface of the DC-SIGN-expressing cells used in this study. Finally, quantitative fluorescence-activated cell sorting analysis of AU1-tagged DC-SIGN revealed that the efficiency of virus transmission was strongly affected by variations in DC-SIGN expression levels. Thus, variations in DC-SIGN expression levels on DCs could greatly affect the susceptibility of human individuals to HIV infection.

scholarly journals Human Immunodeficiency Virus Type 1 Vpr Protein Does Not Modulate Surface Expression of the CD4 Receptor

2002 ◽  
Vol 76 (8) ◽  
pp. 4125-4130 ◽  
Author(s):  
Enrique Argañaraz ◽  
María José Cortés ◽  
Sydney Leibel ◽  
Juan Lama
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Cell Surface ◽  
Target Cells ◽  
Viral Receptor ◽  
Cd4 Receptor ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
Hiv 1

ABSTRACT The CD4 receptor is required for the entry of human immunodeficiency virus (HIV) into target cells. It has long been known that Nef, Env, and Vpu participate in the removal of the viral receptor from the cell surface. Recently, it has been proposed that the HIV type 1 (HIV-1) Vpr protein may also play a role in the downmodulation of CD4 from the surfaces of infected cells (L. Conti, B. Varano, M. C. Gauzzi, P. Matarrese, M. Federico, W. Malorani, F. Belardelli, and S. Gessani, J. Virol. 74:10207-10211, 2000). To investigate the possible role of Vpr in the downregulation of the viral receptor Vpr alleles from HIV-1 and simian immunodeficiency virus were transiently expressed in transformed T cells and in 293T fibroblasts, and their ability to modulate surface CD4 was evaluated. All Vpr alleles efficiently arrested cells in the G2 stage of the cell cycle. However, none of the tested Vpr proteins altered the expression of CD4 on the cell surface. In comparison, HIV-1 Nef efficiently downmodulated surface CD4 in all the experimental settings. Transformed T cells and primary lymphocytes were challenged with wild-type, Nef-defective, and Vpr-defective viruses. A significant reduction in the HIV-induced downmodulation of surface CD4 was observed in viruses lacking Nef. However, Vpr-deletion-containing viruses showed no defect in their ability to remove CD4 from the surfaces of infected cells. Our results indicate that Vpr does not play a role in the HIV-induced downmodulation of the CD4 receptor.

scholarly journals Costimulation of Naive CD8+ Lymphocytes Induces CD4 Expression and Allows Human Immunodeficiency Virus Type 1 Infection

1998 ◽  
Vol 72 (11) ◽  
pp. 9054-9060 ◽  
Author(s):  
Scott G. Kitchen ◽  
Yael D. Korin ◽  
Michael D. Roth ◽  
Alan Landay ◽  
Jerome A. Zack
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Rapid Disease Progression ◽  
Cd8 Cells ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) infection requires cell surface expression of CD4. Costimulation of CD8+/CD4− T lymphocytes by anti-CD3 and anti-CD28 antibodies or by allogeneic dendritic cells induced expression of CD4 and rendered these CD8 cells susceptible to HIV-1 infection. Naive CD45RA+ cells responded with greater expression of CD4 than did CD45RO+ cells. CD8+lymphocytes derived from fetal or newborn sources exhibited a greater tendency to express CD4, consistent with their naive states. This mechanism of infection suggests HIV-induced perturbation of the CD8 arm of the immune response and could explain the generally rapid disease progression seen in HIV-infected children.

scholarly journals Envelope-Dependent, Cyclophilin-Independent Effects of Glycosaminoglycans on Human Immunodeficiency Virus Type 1 Attachment and Infection

2002 ◽  
Vol 76 (12) ◽  
pp. 6332-6343 ◽  
Author(s):  
Yi-jun Zhang ◽  
Theodora Hatziioannou ◽  
Trinity Zang ◽  
Douglas Braaten ◽  
Jeremy Luban ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cell Surface ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Target Cells ◽  
Independent Manner ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Cell surface glycosaminoglycans (GAGs), in particular heparan sulfate (HS), have been proposed to mediate the attachment of human immunodeficiency virus type 1 (HIV-1) to target cells prior to virus entry, and both the viral gp120 envelope protein and virion-associated cyclophilin A (CypA) have been shown to directly interact with HS and its analogues. To determine the role of GAGs in HIV attachment and infection, we generated HIV-susceptible derivatives of CHO cell lines that either express high levels of GAGs (CHO-K1) or lack GAGs (pgsA745). Using a panel of HIV-1 envelopes, we found that cell surface GAG-mediated effects on virion attachment and infection vary in an envelope strain-dependent but coreceptor-independent manner. In fact, cell surface GAG-mediated enhancement of infection is confined to isolates that contain a highly positively charged V3-loop sequence, while infection by most strains is apparently inhibited by the presence of GAGs. Moreover, the enhancing and inhibitory effects of polycations and polyanions on HIV-1 infection are largely dependent on the presence of cell surface GAGs. These observations are consistent with a model in which GAGs influence in vitro HIV-1 infection primarily by modifying the charge characteristics of the target cell surface. Finally, the effects of GAGs on HIV-1 infection are observed to an equivalent extent whether CypA is present in or absent from virions. Overall, these data exclude a major role for GAGs in mediating the attachment of many HIV-1 strains to target cells via interactions with virion-associated gp120 or CypA.

scholarly journals Human Immunodeficiency Virus Type 1 Attachment to HeLa CD4 Cells Is CD4 Independent and gp120 Dependent and Requires Cell Surface Heparans

1998 ◽  
Vol 72 (5) ◽  
pp. 3623-3634 ◽  
Author(s):  
Isabelle Mondor ◽  
Sophie Ugolini ◽  
Quentin J. Sattentau
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cell Surface ◽  
Hela Cells ◽  
Target Cells ◽  
Cd4 Cells ◽  
Virus Binding ◽  
Hla Dr ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The binding of human immunodeficiency virus type 1 (HIV-1) (Hx10) virions to two different cell lines was analyzed by using a novel assay based on the detection, by anti-HLA-DR-specific antibodies, of HLA-DR+ virus binding to HLA-DR− cells. Virion attachment to the CD4+-T-cell line A3.01 was highly CD4 dependent in that it was potently inhibited by CD4 monoclonal antibodies (MAbs), and little virus binding to the CD4−sister A2.01 line was observed. By contrast, virion binding to HeLa cells expressing moderate or high levels of CD4 was equivalent to, or lower than, binding to wild-type CD4− HeLa cells. Moreover, several CD4 MAbs did not reduce, but enhanced, HIV-1 attachment to HeLa-CD4 cells. CD4 was required for infection of HeLa cells, however, demonstrating a postattachment role for this receptor. MAbs specific for the V2 and V3 loops and the CD4i epitope of gp120 strongly inhibited virion binding to HeLa-CD4 cells, whereas MAbs specific for the CD4bs and the 2G12 epitopes enhanced attachment. Despite this, all gp120- and gp41-specific MAbs tested neutralized infectivity on HeLa-CD4 cells. HIV-1 attachment to HeLa cells was only partially inhibited by MAbs specific for adhesion molecules present on the virus or target cells but was completely blocked by polyanions such as heparin, dextran sulfate, and pentosan sulfate. Treatment of HeLa-CD4 cells with heparinases completely eliminated HIV attachment and infection, strongly implicating cell surface heparans in the attachment process. CD4 dependence for HIV-1 attachment to target cells is thus highly cell line specific and may be replaced by other ligand-receptor interactions.

scholarly journals Human immunodeficiency virus 1 downregulates cell surface expression of the non-classical major histocompatibility class I molecule HLA-G1

2004 ◽  
Vol 85 (7) ◽  
pp. 1945-1954 ◽  
Author(s):  
Muriel Derrien ◽  
Nathalie Pizzato ◽  
Guillermina Dolcini ◽  
Elisabeth Menu ◽  
Gérard Chaouat ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cell Surface ◽  
Glioma Cells ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Immunodeficiency Virus ◽  
Immune Defences ◽  
Hiv 1 ◽  
Human Immunodeficiency Virus 1 ◽  
Major Histocompatibility Class I

Human immunodeficiency virus 1 (HIV-1) downregulates cell surface expression of HLA-A and HLA-B but not HLA-C or HLA-E to ultimately escape immune defences. Here, it is shown that cell surface expression of the non-classical HLA-G1 is also downregulated by HIV-1, by using co-transfection experiments and infection with cell-free HIV-1 of HLA-G1-expressing U87 glioma cells or macrophages in primary culture. Moreover, co-transfection experiments using proviruses deleted in either nef or vpu or plasmids encoding HIV-1 Nef and Vpu mixed together with a HLA-G1-expressing construct demonstrated that HLA-G1 downregulation is Nef-independent and Vpu-dependent, contrasting with the Nef- and Vpu-dependent HLA-A2 downregulation. Together, these results show that the decrease of HLA-A2 and HLA-G1 caused by HIV-1 occurs through distinct mechanisms.

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