scholarly journals Direct Evidence of Lower Viral Replication Rates In Vivo in Human Immunodeficiency Virus Type 2 (HIV-2) Infection than in HIV-1 Infection

2007 ◽  
Vol 81 (10) ◽  
pp. 5325-5330 ◽  
Author(s):  
Adam MacNeil ◽  
Abdoulaye Dieng Sarr ◽  
Jean-Louis Sankalé ◽  
Seema Thakore Meloni ◽  
Souleymane Mboup ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Viral Mrna ◽  
Viral Dna ◽  
Viral Loads ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Studies have shown that human immunodeficiency virus type 2 (HIV-2) is less pathogenic than HIV-1, with a lower rate of disease progression. Similarly, plasma viral loads are lower in HIV-2 infection, suggesting that HIV-2 replication is restricted in vivo in comparison to that of HIV-1. However, to date, in vivo studies characterizing replication intermediates in the viral life cycle of HIV-2 have been limited. In order to test the hypothesis that HIV-2 has a lower replication rate in vivo than HIV-1 does, we quantified total viral DNA, integrated proviral DNA, cell-associated viral mRNA, and plasma viral loads in peripheral blood samples from groups of therapy-naïve HIV-1-infected (n = 21) and HIV-2-infected (n = 18) individuals from Dakar, Senegal, with CD4+ T-cell counts of >200/μl. Consistent with our previous findings, total viral DNA loads were similar between HIV-1 and HIV-2 and plasma viral loads were higher among HIV-1-infected individuals. Proportions of DNA in the integrated form were also similar between these viruses. In contrast, levels of viral mRNA were lower in HIV-2 infection. Our study indicates that HIV-2 is able to establish a stable, integrated proviral infection in vivo, but that accumulation of viral mRNA is attenuated in HIV-2 infection relative to that in HIV-1 infection. The differences in viral mRNA are consistent with the differences in plasma viral loads between HIV-1 and HIV-2 and suggest that lower plasma viral loads, and possibly the attenuated pathogenesis of HIV-2, can be explained by lower rates of viral replication in vivo.

scholarly journals Characterization of Simian Immunodeficiency Virus SIVSM/Human Immunodeficiency Virus Type 2 Vpx Function in Human Myeloid Cells

2008 ◽  
Vol 82 (24) ◽  
pp. 12335-12345 ◽  
Author(s):  
Caroline Goujon ◽  
Vanessa Arfi ◽  
Thomas Pertel ◽  
Jeremy Luban ◽  
Julia Lienard ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Simian Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Intracellular Localization ◽  
Lymphoid Cells ◽  
Viral Dna ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 2 (HIV-2)/simian immunodeficiency virus SIVSM Vpx is incorporated into virion particles and is thus present during the early steps of infection, when it has been reported to influence the nuclear import of viral DNA. We recently reported that Vpx promoted the accumulation of full-length viral DNA following the infection of human monocyte-derived dendritic cells (DCs). This positive effect was exerted following the infection of DCs with cognate viruses and with retroviruses as divergent as HIV-1, feline immunodeficiency virus, and even murine leukemia virus, leading us to suggest that Vpx counteracted an antiviral restriction present in DCs. Here, we show that Vpx is required, albeit to a different extent, for the infection of all myeloid but not of lymphoid cells, including monocytes, macrophages, and monocytoid THP-1 cells that had been induced to differentiate with phorbol esters. The intracellular localization of Vpx was highly heterogeneous and cell type dependent, since Vpx localized differently in HeLa cells and DCs. Despite these differences, no clear correlation between the functionality of Vpx and its intracellular localization could be drawn. As a first insight into its function, we determined that SIVSM/HIV-2 and SIVRCM Vpx proteins interact with the DCAF1 adaptor of the Cul4-based E3 ubiquitin ligase complex recently described to associate with HIV-1 Vpr and HIV-2 Vpx. However, the functionality of Vpx proteins in the infection of DCs did not strictly correlate with DCAF1 binding, and knockdown experiments failed to reveal a functional role for this association in differentiated THP-1 cells. Lastly, when transferred in the context of a replication-competent viral clone, Vpx was required for replication in DCs.

scholarly journals Cytopathicity of Human Immunodeficiency Virus Type 2 (HIV-2) in Human Lymphoid Tissue Is Coreceptor Dependent and Comparable to That of HIV-1

2000 ◽  
Vol 74 (20) ◽  
pp. 9594-9600 ◽  
Author(s):  
Birgit Schramm ◽  
Michael L. Penn ◽  
Emil H. Palacios ◽  
Robert M. Grant ◽  
Frank Kirchhoff ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Target Cell ◽  
Lymphoid Tissue ◽  
Immunodeficiency Virus ◽  
The Impact ◽  
Hiv 1

ABSTRACT Epidemiological studies have shown that human immunodeficiency virus type 2 (HIV-2) is markedly less pathogenic than HIV-1 in vivo. Individuals infected with HIV-2 exhibit a remarkably slow rate of disease development, and these clinical properties have been attributed presumptively to an “attenuated” phenotype of HIV-2 itself. Here, we investigated the impact of coreceptor usage on the cytopathicity of HIV-2 and compared its pathogenic potential with that of HIV-1 in a unique human lymphoid histoculture model. We found that HIV-2 strains, as well as closely related simian immunodeficiency viruses (SIV), displayed mildly or highly aggressive cytopathic phenotypes depending on their abilities to use the coreceptor CCR5 or CXCR4, respectively. A side-by-side comparison of primary X4 HIV-1 and HIV-2 strains revealed similar, high degrees of cytopathicity induced by both HIV types. Furthermore, we found that HIV-2 coreceptor specificity for CCR5 and CXCR4 determined the target cell population for T-cell depletion in lymphoid tissue. Finally, utilization of the alternate coreceptors BOB and Bonzo did not significantly increase the cytopathic properties of HIV-2. These findings demonstrate that coreceptor preference is a key regulator of target cell specificity and the cytopathic potential of HIV-2, with indistinguishable rules compared with HIV-1. Moreover, HIV-2 strains are not characterized by an intrinsically lower cytopathicity than HIV-1 strains. Therefore, direct cytopathic potential per se does not explain the unique behavior of HIV-2 in people, highlighting that other unknown factors need to be elucidated as the basis for their lesser virulence in vivo.

scholarly journals The Human Immunodeficiency Virus Type 1nef Gene Can to a Large Extent Replace Simian Immunodeficiency Virus nef In Vivo

1999 ◽  
Vol 73 (10) ◽  
pp. 8371-8383 ◽  
Author(s):  
Frank Kirchhoff ◽  
Jan Münch ◽  
Silke Carl ◽  
Nicole Stolte ◽  
Kerstin Mätz-Rensing ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Viral Replication ◽  
Simian Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Viral Loads ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Chimeric Viruses

ABSTRACT The nef gene of the pathogenic simian immunodeficiency virus (SIV) 239 clone was replaced with primary human immunodeficiency virus type 1 (HIV-1) nef alleles to investigate whether HIV-1 Nef can substitute for SIV Nef in vivo. Initially, two rhesus macaques were infected with the chimeric viruses (Nef-SHIVs). Most of the nef alleles obtained from both animals predicted intact open reading frames. Furthermore, forms containing upstream nucleotide substitutions that enhanced expression of the inserted gene became predominant. One animal maintained high viral loads and slowly progressed to immunodeficiency. nef long terminal repeat sequences amplified from this animal were used to generate a second generation of Nef-SHIVs. Two macaques, which were subsequently infected with a mixture of cloned chimeric viruses, showed high viral loads and progressed to fatal immunodeficiency. Five macaques received a single molecular clone, named SHIV-40K6. The SHIV-40K6 nef allele was active in CD4 and class I major histocompatibility complex downregulation and enhanced viral infectivity and replication. Notably, all of the macaques inoculated with SHIV-40K6 showed high levels of viral replication early in infection. During later stages, however, the course of infection was variable. Three animals maintained high viral loads and developed immunodeficiency. Of the remaining two macaques, which showed decreasing viral loads after the acute phase of infection, only one efficiently controlled viral replication and remained asymptomatic during 1.5 years of follow-up. The other animal showed an increasing viral load and developed signs of progressive infection during later stages. Our data demonstrate that HIV-1 nefcan, to a large extent, functionally replace SIVmac nef in vivo.

scholarly journals Human Immunodeficiency Virus Type 1 Nucleocapsid Zn2+ Fingers Are Required for Efficient Reverse Transcription, Initial Integration Processes, and Protection of Newly Synthesized Viral DNA

2003 ◽  
Vol 77 (2) ◽  
pp. 1469-1480 ◽  
Author(s):  
James S. Buckman ◽  
William J. Bosche ◽  
Robert J. Gorelick
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Reverse Transcription ◽  
Full Length ◽  
Viral Dna ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) containing mutations in the nucleocapsid (NC) Zn2+ finger domains have greatly reduced infectivity, even though genome packaging is largely unaffected in certain cases. To examine replication defects, viral DNA (vDNA) was isolated from cells infected with viruses containing His-to-Cys changes in their Zn2+ fingers (NCH23C and NCH44C), an integrase mutant (IND116N), a double mutant (NCH23C/IND116N), or wild-type HIV-1. In vitro assays have established potential roles for NC in reverse transcription and integration. In vivo results for these processes were obtained by quantitative PCR, cloning of PCR products, and comparison of the quantity and composition of vDNA generated at discrete points during reverse transcription. Quantitative analysis of the reverse transcription intermediates for these species strongly suggests decreased stability of the DNA produced. Both Zn2+ finger mutants appear to be defective in DNA synthesis, with the minus- and plus-strand transfer processes being affected while interior portions of the vDNA remain more intact. Sequences obtained from PCR amplification and cloning of 2-LTR circle junction fragments revealed that the NC mutants had a phenotype similar to the IN mutant; removal of the terminal CA dinucleotides necessary for integration of the vDNA is disabled by the NC mutations. Thus, the loss of infectivity in these NC mutants in vivo appears to result from defective reverse transcription and integration processes stemming from decreased protection of the full-length vDNA. Finally, these results indicate that the chaperone activity of NC extends from the management of viral RNA through to the full-length vDNA.

scholarly journals Specific and Independent Recognition of U3 and U5att Sites by Human Immunodeficiency Virus Type 1 Integrase In Vivo

1998 ◽  
Vol 72 (10) ◽  
pp. 8396-8402 ◽  
Author(s):  
Takao Masuda ◽  
Marcelo J. Kuroda ◽  
Shinji Harada
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Proviral Integration ◽  
Viral Dna ◽  
Immunodeficiency Virus ◽  
Dna Ends ◽  
Hiv 1

ABSTRACT The retroviral attachment (att) sites at viral DNA ends are cis-acting regions essential for proviral integration. To investigate the sequence features of att important for human immunodeficiency virus type 1 (HIV-1) integration in vivo, we generated a series of 25 att mutants of HIV-1 by mutagenesis of the U3, U5, or both boundaries of att. Our results indicated that the terminal 11 or 12 bp of viral DNA are sufficient for specific recognition by HIV-1 integrase (IN) and suggested that IN might recognize each att site independently in vivo.

scholarly journals Allogeneic leukocytes but not therapeutic blood elements induce reactivation and dissemination of latent human immunodeficiency virus type 1 infection: implications for transfusion support of infected patients

Blood ◽  
1992 ◽  
Vol 80 (8) ◽  
pp. 2128-2135 ◽  
Author(s):  
MP Busch ◽  
TH Lee ◽  
J Heitman
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Blood Components ◽  
Route Of Transmission ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Donor Lymphocytes

Abstract Various immunologic stimuli and heterologous viral regulatory elements have been shown to increase susceptibility to, and replication of, human immunodeficiency virus type 1 (HIV-1) in lymphocytes and monocytes in vitro. Transfusion of allogeneic blood components from heterologous donors constitutes a profound immunologic stimulus to the recipient, in addition to being a potential route of transmission of lymphotropic viral infections. To investigate the hypothesis that transfusions, and particularly those containing leukocytes, activate HIV-1 replication in infected recipient cells, we cocultured peripheral blood mononuclear cells (PBMC) from three anti-HIV-1-positive individuals with allogeneic donor PBMC, as well as partially purified populations of donor lymphocytes, monocytes, granulocytes, platelets, and red blood cells (RBC) and allogeneic cell-free plasma. Allogeneic PBMC induced a dose-related activation of HIV-1 expression in in vivo infected cells, followed by dissemination of HIV-1 to previously uninfected patient cells. Activation of HIV-1 replication was observed with donor lymphocytes, monocytes, and granulocytes, whereas no effect was seen with leukocyte-depleted RBC, platelets, or plasma (ie, therapeutic blood constituents). Allogeneic donor PBMC were also shown to upregulate HIV-1 expression in a “latently” infected cell line, and to increase susceptibility of heterologous donor PBMC to acute HIV-1 infection. Studies should be performed to evaluate whether transfusions of leukocyte-containing blood components accelerate HIV-1 dissemination and disease progression in vivo. If so, HIV-1-infected patients should be transfused as infrequently as possible and leukocyte-depleted (filtered) blood components should be used to avoid this complication.

scholarly journals The Interaction of Vpr with Uracil DNA Glycosylase Modulates the Human Immunodeficiency Virus Type 1 In Vivo Mutation Rate

2000 ◽  
Vol 74 (15) ◽  
pp. 7039-7047 ◽  
Author(s):  
Louis M. Mansky ◽  
Sandra Preveral ◽  
Luc Selig ◽  
Richard Benarous ◽  
Serge Benichou
Keyword(s):  
Human Immunodeficiency Virus ◽  
Mutation Rate ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Dna Glycosylase ◽  
Uracil Dna Glycosylase ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The Vpr protein of human immunodeficiency virus type 1 (HIV-1) influences the in vivo mutation rate of the virus. Since Vpr interacts with a cellular protein implicated in the DNA repair process, uracil DNA glycosylase (UNG), we have explored the contribution of this interaction to the mutation rate of HIV-1. Single-amino-acid variants of Vpr were characterized for their differential UNG-binding properties and used to trans complement vpr null mutant HIV-1. A striking correlation was established between the abilities of Vpr to interact with UNG and to influence the HIV-1 mutation rate. We demonstrate that Vpr incorporation into virus particles is required to influence the in vivo mutation rate and to mediate virion packaging of the nuclear form of UNG. The recruitment of UNG into virions indicates a mechanism for how Vpr can influence reverse transcription accuracy. Our data suggest that distinct mechanisms evolved in primate and nonprimate lentiviruses to reconcile uracil misincorporation into lentiviral DNA.

scholarly journals Human Immunodeficiency Virus Type 1 Nucleocapsid Protein Nuclear Localization Mediates Early Viral mRNA Expression

2002 ◽  
Vol 76 (20) ◽  
pp. 10444-10454 ◽  
Author(s):  
Jielin Zhang ◽  
Clyde S. Crumpacker
Keyword(s):  
Human Immunodeficiency Virus ◽  
Mrna Expression ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Nucleocapsid Protein ◽  
Viral Mrna ◽  
Genomic Rna ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT An important aspect of the pathophysiology of human immunodeficiency virus type 1 (HIV-1) infection is the ability of the virus to replicate in the host vigorously without a latent phase and to kill cells with a dynamic turnover of 1.8 × 109 cells/day and 10.3 × 109 virions/24 h. The transcription of HIV-1 RNA in acute infection occurs at two stages; the transcription of viral spliced mRNA occurs early, and the transcription of viral genomic RNA occurs later. The HIV-1 Tat protein is translated from the early spliced mRNA and is critical for HIV-1 genomic RNA expression. The cellular transcription factors are important for HIV-1 early spliced mRNA expression. In this study we show that virion nucleocapsid protein (NC) has a role in expression of HIV-1 early spliced mRNA. The HIV-1 NC migrates from the cytoplasm to the nucleus and accumulates in the nucleus at 18 h postinfection. Mutations on HIV-1 NC zinc fingers change the pattern of early viral spliced mRNA expression and result in a delayed expression of early viral mRNA in HIV-infected cells. This delayed HIV-1 early spliced mRNA expression occurs after proviral DNA has been integrated into the cellular genome, as shown by a quantitative integration assay. These results show that virion NC plays an important role in inducing HIV-1 early mRNA expression and contributes to the rapid viral replication that occurs during HIV-1 infection.

scholarly journals In vivo characteristics of human immunodeficiency virus type 1 intersubtype recombination: determination of hot spots and correlation with sequence similarity

2003 ◽  
Vol 84 (10) ◽  
pp. 2715-2722 ◽  
Author(s):  
Gkikas Magiorkinis ◽  
Dimitrios Paraskevis ◽  
Anne-Mieke Vandamme ◽  
Emmanouil Magiorkinis ◽  
Vana Sypsa ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Recombination Frequency ◽  
Sequence Similarity ◽  
Virus Species ◽  
Immunodeficiency Virus ◽  
Hiv 1

Recombination plays a pivotal role in the evolutionary process of many different virus species, including retroviruses. Analysis of all human immunodeficiency virus type 1 (HIV-1) intersubtype recombinants revealed that they are more complex than described initially. Recombination frequency is higher within certain genomic regions, such as partial reverse transcriptase (RT), vif/vpr, the first exons of tat/rev, vpu and gp41. A direct correlation was observed between recombination frequency and sequence similarity across the HIV-1 genome, indicating that sufficient sequence similarity is required upstream of the recombination breakpoint. This finding suggests that recombination in vivo may occur preferentially during reverse transcription through the strand displacement-assimilation model rather than the copy-choice model.

scholarly journals Mutations in the Human Immunodeficiency Virus Type 1 Integrase D,D(35)E Motif Do Not Eliminate Provirus Formation

1998 ◽  
Vol 72 (6) ◽  
pp. 4678-4685 ◽  
Author(s):  
Meenakshi Gaur ◽  
Andrew D. Leavitt
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Viral Genome ◽  
Viral Dna ◽  
Infectious Titer ◽  
Immunodeficiency Virus ◽  
Acidic Residues ◽  
Hiv 1

ABSTRACT The core domain of human immunodeficiency virus type 1 (HIV-1) integrase (IN) contains a D,D(35)E motif, named for the phylogenetically conserved glutamic acid and aspartic acid residues and the invariant 35 amino acid spacing between the second and third acidic residues. Each acidic residue of the D,D(35)E motif is independently essential for the 3′-processing and strand transfer activities of purified HIV-1 IN protein. Using a replication-defective viral genome with a hygromycin selectable marker, we recently reported that a mutation at any of the three residues of the D,D(35)E motif produces a 103- to 104-fold reduction in infectious titer compared with virus encoding wild-type IN (A. D. Leavitt et al., J. Virol. 70:721–728. 1996). The infectious titer, as measured by the number of hygromycin-resistant colonies formed following infection of cells in culture, was less than a few hundred colonies per μg of p24. To understand the mechanism by which the mutant virions conferred hygromycin resistance, we characterized the integrated viral DNA in cells infected with virus encoding mutations at each of the three residues of the D,D(35)E motif. We found the integrated viral DNA to be colinear with the incoming viral genome. DNA sequencing of the junctions between integrated viral DNA and host DNA showed that (i) the characteristic 5-bp direct repeat of host DNA flanking the HIV-1 provirus was not maintained, (ii) integration often produced a deletion of host DNA, (iii) integration sometimes occurred without the viral DNA first undergoing 3′-processing, (iv) integration sites showed a strong bias for a G residue immediately adjacent to the conserved viral CA dinucleotide, and (v) mutations at each of the residues of the D,D(35)E motif produced essentially identical phenotypes. We conclude that mutations at any of the three acidic residues of the conserved D,D(35)E motif so severely impair IN activity that most, if not all, integration events by virus encoding such mutations are not IN mediated. IN-independent provirus formation may have implications for anti-IN therapeutic agents that target the IN active site.

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