scholarly journals Intrapatient Alterations in the Human Immunodeficiency Virus Type 1 gp120 V1V2 and V3 Regions Differentially Modulate Coreceptor Usage, Virus Inhibition by CC/CXC Chemokines, Soluble CD4, and the b12 and 2G12 Monoclonal Antibodies

2004 ◽  
Vol 78 (1) ◽  
pp. 524-530 ◽  
Author(s):  
Alexey A. Nabatov ◽  
Georgios Pollakis ◽  
Thomas Linnemann ◽  
Aletta Kliphius ◽  
Moustapha I. M. Chalaby ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Monoclonal Antibodies ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Genetic Alterations ◽  
Coreceptor Usage ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Soluble Cd4

ABSTRACT We studied human immunodeficiency virus type 1 (HIV-1) chimeric viruses altering in their gp120 V1V2 and V3 envelope regions to better map which genetic alterations are associated with specific virus phenotypes associated with HIV-1 disease progression. The V1V2 and V3 regions studied were based on viruses isolated from an individual with progressing HIV-1 disease. Higher V3 charges were linked with CXCR4 usage, but only when considered within a specific V1V2 and V3 N-linked glycosylation context. When the virus gained R5X4 dual tropism, irrespective of its V3 charge, it became highly resistant to inhibition by RANTES and highly sensitive to inhibition by SDF-1α. R5 viruses with higher positive V3 charges were more sensitive to inhibition by RANTES, while R5X4 dualtropic viruses with higher positive V3 charges were more resistant to inhibition by SDF-1α. Loss of the V3 N-linked glycosylation event rendered the virus more resistant to inhibition by SDF-1α. The same alterations in the V1V2 and V3 regions influenced the extent to which the viruses were neutralized with soluble CD4, as well as monoclonal antibodies b12 and 2G12, but not monoclonal antibody 2F5. These results further identify a complex set of alterations within the V1V2 and V3 regions of HIV-1 that can be selected in the host via alterations of coreceptor usage, CC/CXC chemokine inhibition, CD4 binding, and antibody neutralization.

scholarly journals Antibody-Dependent Cellular Cytotoxicity Directed against Cells Expressing Human Immunodeficiency Virus Type 1 Envelope of Primary or Laboratory-Adapted Strains by Human and Chimpanzee Monoclonal Antibodies of Different Epitope Specificities

1998 ◽  
Vol 72 (1) ◽  
pp. 286-293 ◽  
Author(s):  
Osama Alsmadi ◽  
Shermaine A. Tilley
Keyword(s):  
Human Immunodeficiency Virus ◽  
Monoclonal Antibodies ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cellular Cytotoxicity ◽  
Antibody Dependent Cellular Cytotoxicity ◽  
Adcc Activity ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The characteristics of antibody-dependent cellular cytotoxicity (ADCC) directed by a panel of human and chimpanzee antienvelope (anti-Env) monoclonal antibodies (MAbs) of different epitope specificities were studied; this was accomplished by using target cells expressing human immunodeficiency virus type 1 (HIV-1) Envs of either primary or laboratory-adapted strains. Human MAbs of similar apparent affinities (1 × 109 to 2 × 109 liters/mol) against either a “cluster II”-overlapping epitope of gp41 or against the CD4 binding site, V3 loop, or C5 domain of gp120 directed substantial and comparable levels of specific lysis against targets infected with laboratory-adapted strains of HIV-1. As expected, those MAbs specific for relatively conserved regions of Env generally exhibited ADCC activity against a broader range of HIV-1 strains than those directed against variable epitopes. Significant ADCC activities of selected MAbs against primary isolate Env-expressing cells were demonstrated. In addition, a new ADCC epitope in the V2 domain of gp120 was defined. CD56+ cells were demonstrated to be the effector cells in these studies by fluorescence-activated cell sorting followed by ADCC assays. Notably, all anti-Env MAbs tested in this study, including MAbs directed against each of the known neutralization epitope clusters in gp120, directed significant levels of ADCC against targets expressing Env of one or more HIV-1 strains. These results imply that many, if not most, HIV-1-neutralizing human Abs of high affinity (≥3 × 108 liters/mol in these studies) and of the immunoglobulin G1 (IgG1) subclass (i.e., the predominate IgG subclass) are capable of directing ADCC. Since neutralizing Abs have been associated with long-term survival following HIV-1 infection, this suggests that ADCC activity may be beneficial in vivo.

scholarly journals Evolution of Human Immunodeficiency Virus Type 1 Coreceptor Usage during Antiretroviral Therapy: a Bayesian Approach

2004 ◽  
Vol 78 (20) ◽  
pp. 11296-11302 ◽  
Author(s):  
Christina M. R. Kitchen ◽  
Sean Philpott ◽  
Harold Burger ◽  
Barbara Weiser ◽  
Kathryn Anastos ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiretroviral Therapy ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Coreceptor Usage ◽  
Hierarchical Approach ◽  
Bayesian Hierarchical ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT There is substantial evidence for ongoing replication and evolution of human immunodeficiency virus type 1 (HIV-1), even in individuals receiving highly active antiretroviral therapy. Viral evolution in the presence of antiviral therapy needs to be considered when developing new therapeutic strategies. Phylogenetic analyses of HIV-1 sequences can be used for this purpose but may give rise to misleading results if rates of intrapatient evolution differ significantly. To improve analyses of HIV-1 evolution relevant to studies of pathogenesis and treatment, we developed a Bayesian hierarchical model that incorporates all available sequence data while simultaneously allowing the phylogenetic parameters of each patient to vary. We used this method to examine evolutionary changes in HIV-1 coreceptor usage in response to treatment. We examined patients whose viral populations exhibited a shift in coreceptor utilization in response to therapy. CXCR4 (X4) strains emerged in each patient but were suppressed following initiation of new antiretroviral regimens, so that CCR5-utilizing (R5) strains predominated. By phylogenetically reconstructing the evolutionary relationship of HIV-1 obtained longitudinally from each patient, it was possible to examine the origin of the reemergent R5 virus. Using our Bayesian hierarchical approach, we found that the reemergent R5 virus detectable after therapy was more closely related to the predecessor R5 virus than to the X4 strains. The Bayesian hierarchical approach, unlike more traditional methods, makes it possible to evaluate competing hypotheses across patients. This model is not limited to analyses of HIV-1 but can be used to elucidate evolutionary processes for other organisms as well.

scholarly journals Nef Does Not Affect the Efficiency of Human Immunodeficiency Virus Type 1 Fusion with Target Cells

2003 ◽  
Vol 77 (19) ◽  
pp. 10645-10650 ◽  
Author(s):  
Minoru Tobiume ◽  
Janet E. Lineberger ◽  
Christopher A. Lundquist ◽  
Michael D. Miller ◽  
Christopher Aiken
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Intracellular Transport ◽  
Target Cells ◽  
Wild Type ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Soluble Cd4

ABSTRACT The human immunodeficiency virus type 1 (HIV-1) accessory protein Nef stimulates viral infectivity by an unknown mechanism. Recent studies have suggested that Nef may act by regulating the efficiency of virus entry into cells. Here we provide evidence to the contrary. Using a quantitative assay of HIV-1 virus-cell fusion, we observed equivalent rates and extents of fusion of wild-type and Nef-defective HIV-1 particles with MT-4 cells and CD4-expressing HeLa cells. In studies using soluble CD4 (sCD4) to inhibit infection, wild-type and Nef-defective HIV-1 escaped the sCD4 block with similar kinetics. We conclude that Nef acts at a postentry step in infection, probably by facilitating intracellular transport of the HIV-1 ribonucleoprotein complex.

scholarly journals Evidence that Antibody-Mediated Neutralization of Human Immunodeficiency Virus Type 1 by Sera from Infected Individuals Is Independent of Coreceptor Usage

1998 ◽  
Vol 72 (3) ◽  
pp. 1886-1893 ◽  
Author(s):  
David C. Montefiori ◽  
Ronald G. Collman ◽  
Timothy R. Fouts ◽  
Ji Ying Zhou ◽  
Miroslawa Bilska ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Coreceptor Usage ◽  
Peripheral Blood Mononuclear ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) uses a variety of chemokine receptors as coreceptors for virus entry, and the ability of the virus to be neutralized by antibody may depend on which coreceptors are used. In particular, laboratory-adapted variants of the virus that use CXCR4 as a coreceptor are highly sensitive to neutralization by sera from HIV-1-infected individuals, whereas primary isolates that use CCR5 instead of, or in addition to, CXCR4 are neutralized poorly. To determine whether this dichotomy in neutralization sensitivity could be explained by differential coreceptor usage, virus neutralization by serum samples from HIV-1-infected individuals was assessed in MT-2 cells, which express CXCR4 but not CCR5, and in mitogen-stimulated human peripheral blood mononuclear cells (PBMC), where multiple coreceptors including CXCR4 and CCR5 are available for use. Our results showed that three of four primary isolates with a syncytium-inducing (SI) phenotype and that use CXCR4 and CCR5 were neutralized poorly in both MT-2 cells and PBMC. The fourth isolate, designated 89.6, was more sensitive to neutralization in MT-2 cells than in PBMC. We showed that the neutralization of 89.6 in PBMC was not improved when CCR5 was blocked by having RANTES, MIP-1α, and MIP-1β in the culture medium, indicating that CCR5 usage was not responsible for the decreased sensitivity to neutralization in PBMC. Consistent with this finding, a laboratory-adapted strain of virus (IIIB) was significantly more sensitive to neutralization in CCR5-deficient PBMC (homozygous Δ32-CCR5 allele) than were two of two SI primary isolates tested. The results indicate that the ability of HIV-1 to be neutralized by sera from infected individuals depends on factors other than coreceptor usage.

scholarly journals Neutralizing Monoclonal Antibodies Block Human Immunodeficiency Virus Type 1 Infection of Dendritic Cells and Transmission to T Cells

1998 ◽  
Vol 72 (12) ◽  
pp. 9788-9794 ◽  
Author(s):  
Sarah S. Frankel ◽  
Ralph M. Steinman ◽  
Nelson L. Michael ◽  
Silvia Ratto Kim ◽  
Nina Bhardwaj ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Dendritic Cells ◽  
Monoclonal Antibodies ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Prevention of the initial infection of mucosal dendritic cells (DC) and interruption of the subsequent transmission of HIV-1 from DC to T cells are likely to be important attributes of an effective human immunodeficiency virus type 1 (HIV-1) vaccine. While anti-HIV-1 neutralizing antibodies have been difficult to elicit by immunization, there are several human monoclonal antibodies (MAbs) that effectively neutralize virus infection of activated T cells. We investigated the ability of three well-characterized neutralizing MAbs (IgG1b12, 2F5, and 2G12) to block HIV-1 infection of human DC. DC were generated from CD14+ blood cells or obtained from cadaveric human skin. The MAbs prevented viral entry into purified DC and the ensuing productive infection in DC/T-cell cultures. When DC were first pulsed with HIV-1, MAbs blocked the subsequent transmission to unstimulated CD3+ T cells. Thus, neutralizing antibodies can block HIV-1 infection of DC and the cell-to-cell transmission of virus from infected DC to T cells. These data suggest that neutralizing antibodies could interrupt the initial events associated with mucosal transmission and regional spread of HIV-1.

scholarly journals Antibody-Mediated Enhancement of Human Immunodeficiency Virus Type 1 Infectivity Is Determined by the Structure of gp120 and Depends on Modulation of the gp120-CCR5 Interaction

2002 ◽  
Vol 76 (6) ◽  
pp. 2827-2834 ◽  
Author(s):  
Christophe Guillon ◽  
Martin Schutten ◽  
Patrick H. M. Boers ◽  
Rob A. Gruters ◽  
Albert D. M. E. Osterhaus
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Coreceptor Usage ◽  
Main Determinant ◽  
Immunodeficiency Virus ◽  
Viral Determinants ◽  
V3 Region ◽  
Hiv 1

ABSTRACT In this study, we characterized the viral determinants of coreceptor usage in relation to susceptibility to antibody-mediated neutralization or enhancement of infectivity by using chimeras of three highly related human immunodeficiency virus type 1 (HIV-1) isolates of different phenotypes. We found that the V3 region was the main determinant of antibody-mediated enhancement and coreceptor specificity but that the overall structure of gp120 was also important for these properties. Constructs susceptible to antibody-mediated enhancement preferentially use CCR5 as a coreceptor, in contrast to constructs that were neutralized or not affected. Using monoclonal antibodies directed against CD4 or CCR5, we were able to show that antibody-mediated enhancement was CD4 dependent. Altogether, our results suggest that the modulation of the interaction of gp120 with CCR5 is the mechanism underlying antibody-mediated enhancement of HIV-1 infectivity.

The role of viral coreceptors and enhanced macrophage tropism in human immunodeficiency virus type 1 disease progression

Sexual Health ◽  
2004 ◽  
Vol 1 (1) ◽  
pp. 23 ◽  
Author(s):  
Paul R. Gorry ◽  
Jasminka Sterjovski ◽  
Melissa Churchill ◽  
Kristie Witlox ◽  
Lachlan Gray ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Disease Progression ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Molecular Mechanisms ◽  
Coreceptor Usage ◽  
Immunodeficiency Virus ◽  
The Impact ◽  
Hiv 1

Despite numerous studies on the impact of viral diversity, human immunodeficiency virus type 1 (HIV-1)-specific immune responses and host factors on disease progression, we still do not have a firm understanding of the long-term pathogenesis of HIV-1 infection. Rapid depletion of CD4+ T-lymphocytes has been associated with a switch in viral coreceptor usage from CCR5 to CXCR4 in ~40 to 50% of infected individuals. However, the majority of infected individuals who progress to AIDS harbour only CCR5-dependent (R5) viral strains. The progression HIV-1 disease is associated with an enhanced tropism of R5 viral strains for monocyte/macrophage lineage cells (enhanced M-tropism). However, the underlying molecular mechanisms contributing to enhanced M-tropism by R5 HIV-1 strains, and how HIV-1 variants with enhanced M-tropism cause CD4+ T-cell depletion in vivo are unknown. This review examines the relationship between viral coreceptor usage, M-tropism, and pathogenicity of HIV-1. We highlight evidence supporting the hypothesis that enhanced M-tropism of R5 HIV-1 results from adaptive viral evolution, resulting in HIV-1 variants that have increased ability to utilise relatively low levels of CCR5 expressed on macrophages, by way of increased CCR5 affinity. The evidence also suggests that these late-emerging, R5 viral strains have reduced sensitivity to entry inhibitors, and increased ability to cause CD4+ T-lymphocyte loss. These variants are likely to impact HIV-1 disease progression, especially in patients who persistently harbour only R5 viral strains.

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