scholarly journals The human immunodeficiency virus-1 nef gene product: a positive factor for viral infection and replication in primary lymphocytes and macrophages.

1994 ◽  
Vol 179 (1) ◽  
pp. 101-113 ◽  
Author(s):  
M D Miller ◽  
M T Warmerdam ◽  
I Gaston ◽  
W C Greene ◽  
M B Feinberg

Considerable controversy and uncertainty have surrounded the biological function of the Human Immunodeficiency Virus (HIV)-1 nef gene product. Initial studies suggested that this early, nonstructural viral protein functioned as a negative regulatory factor; thus, it was proposed to play a role in establishing or maintaining viral latency. In contrast, studies in Simian Immunodeficiency Virus (SIV)mac-infected rhesus monkeys have suggested that Nef is not a negative factor but rather plays a central role in promoting high-level viral replication and is required for viral pathogenesis in vivo. We sought to define a tissue culture system that would approximate the in vivo setting for virus infection in order to assess the role of HIV-1 Nef in viral replication. We show that infection of mitogen-activated peripheral blood mononuclear cells (PBMC) with Nef+ HIV results in enhanced replication as evidenced by earlier gag p24 expression when compared with infections performed with nef mutant viruses. Moreover, when unstimulated freshly isolated PBMC are infected with Nef+ and Nef- viruses and then subsequently activated with mitogen, the Nef-induced difference in viral replication kinetics is even more pronounced, with the Nef- viruses requiring much more time in culture for appreciable growth. A positive effect of Nef on viral replication was also observed in primary macrophages infected with a recombinant of YU-2, a patient-derived molecular clone with macrophage tropism. These positive effects of Nef on viral replication are dependent on the initial multiplicity of infection (MOI), in that infections of unstimulated PBMC at low MOI are most dependent upon intact nef for subsequent viral growth. We now provide evidence that the Nef+ HIV is more infectious than Nef- HIV from both a tissue culture infectious dose analysis, and a single-cell HIV infection assay. In the latter case, we demonstrate that infection with equivalent doses of HIV based on virion-associated gag p24 yields five- to sixfold more infected cells if Nef+ viral stocks were used. Furthermore, we find that the differential infectivity is not dependent on CD4 down-regulation as Nef+ virus produced from transfected COS cells lacking CD4 is also more infectious. However, normalization of PBMC infections to equivalent infectivity between that of the Nef+ and Nef- viruses continues to reveal delayed viral replication in the absence of Nef, suggesting that secondary viral spread in PBMC is also enhanced in Nef+ infections. We demonstrate this directly by showing a 13-15-fold increase in infectivity of PBMC-derived Nef+ HIC.(ABSTRACT TRUNCATED AT 400 WORDS)

1992 ◽  
Vol 3 (2) ◽  
pp. 107-112 ◽  
Author(s):  
D. Kinchington ◽  
J. J. Harvey ◽  
T. J. O'Connor ◽  
B. C. N. M. Jones ◽  
K. G. Devine ◽  
...  

A number of zidovudine phosphoramidate and phosphorodiamidate derivatives were prepared, including some previously unreported benzyl esterified amino acyl compounds. These were found to be active in vitro against the human immunodeficiency virus (HIV-1), and were tested subsequently in the S+L-tissue culture assay against urethane leukaemia virus (ULV), a murine leukaemia virus (MuLV). The fifteen compounds tested showed a similar range of activity against the two viruses. No active compounds were missed in the MuLV system which was usually more sensitive to antiviral effects. Five compounds showed some toxicity to the mouse cells only. We are using this system in parallel with HIV assays to identify those derivatives which will be tested subsequently against a murine retrovirus in vivo.


PEDIATRICS ◽  
1991 ◽  
Vol 87 (6) ◽  
pp. 921-925
Author(s):  
Isaac Srugo ◽  
Philip A. Brunell ◽  
Nickolas V. Chelyapov ◽  
Victor lsraele ◽  
David D. Ho ◽  
...  

The human immunodeficiency virus type 1 (HIV-1) was isolated from the plasma and peripheral blood mononuclear cells (PBMCs) from each of 21 infected children. The mean titers in plasma were 7 and 165 tissue culture-infective doses per milliliter in 9 children with asymptomatic (P-1) and 12 with symptomatic (P-2) infection, respectively (P = .0013). Significantly higher viral titers were found in PBMCs obtained from P-2 compared with P-1 children: 1920 vs 25 tissue culture-infective doses per 106 PBMC (P = .0018). In symptomatic patients at least 1 in 520 circulating mononuclear cells harbored HIV-1. No correlation was found between the viral burden and CD4+ lymphocyte counts. A decrease in the HIV-1 titers was noted both in PBMCs and plasma of symptomatic patients treated with zidovudine for 2 to 7 months. It is concluded that symptomatic children harbor a higher amount of the virus in plasma and PBMCs than asymptomatic children. Zidovudine treatment for 2 months or more decreased the amount of HIV-1 in PBMCs and plasma.


2004 ◽  
Vol 78 (21) ◽  
pp. 12054-12057 ◽  
Author(s):  
Fabienne Rayne ◽  
Agnès Vendeville ◽  
Anne Bonhoure ◽  
Bruno Beaumelle

ABSTRACT Hydroxychloroquine at 1 μM reduces the load of human immunodeficiency virus type 1 (HIV-1) in patients, whereas chloroquine (CQ) concentrations above 3 μM are required for inhibition of HIV-1 replication in peripheral blood mononuclear cells. Exogenous HIV-1 Tat reaches the cytosol of T cells by using low endosomal pH, and endosome neutralization by CQ prevents Tat from entering and affecting T cells. We show here that 0.6 μM CQ inhibits cytokine secretion induced by Tat in monocytes without affecting lipopolysaccharide-triggered cytokine release. This finding suggests that the in vivo anti-HIV-1 effect of CQ results not from a direct effect on the infected cell but rather from the capacity of CQ to prevent Tat from perturbing the cytokine balance.


1999 ◽  
Vol 73 (10) ◽  
pp. 8371-8383 ◽  
Author(s):  
Frank Kirchhoff ◽  
Jan Münch ◽  
Silke Carl ◽  
Nicole Stolte ◽  
Kerstin Mätz-Rensing ◽  
...  

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.


1998 ◽  
Vol 72 (7) ◽  
pp. 6260-6263 ◽  
Author(s):  
Christophe Guillon ◽  
Marchina E. van der Ende ◽  
Patrick H. M. Boers ◽  
Rob A. Gruters ◽  
Martin Schutten ◽  
...  

ABSTRACT Entry of human immunodeficiency virus type 1 (HIV-1) into target cells is mediated by binding of the surface envelope glycoprotein to the CD4 molecule. Interaction of the resulting CD4-glycoprotein complex with α- or β-chemokine receptors, depending on the biological phenotype of the virus, then initiates the fusion process. Here, we show that primary HIV-2 isolates and biological clones, in contrast to those of HIV-1, may use a broad range of coreceptors, including CCR-1, CCR-3, CCR-5, and CXCR-4. The syncytium-inducing capacity of these viruses did not correlate with the ability to infect via CXCR-4 or any other coreceptor. One cell-free passage of the intermediate isolates in mitogen-stimulated, CD8+ cell-depleted peripheral blood mononuclear cells resulted in the outgrowth of variants with CCR-5 only, whereas the coreceptor usage of late and early isolates did not change. Since HIV-2 is less pathogenic in vivo than HIV-1, these data suggest that HIV pathogenicity in vivo is not directly related to the spectrum of coreceptors used in in vitro systems.


2007 ◽  
Vol 81 (20) ◽  
pp. 11549-11552 ◽  
Author(s):  
Tatsuhiko Igarashi ◽  
Ranjini Iyengar ◽  
Russel A. Byrum ◽  
Alicia Buckler-White ◽  
Robin L. Dewar ◽  
...  

ABSTRACT A human immunodeficiency virus type 1 (HIV-1) derivative (HIVNL-DT5R) containing sequences encoding a 7-amino-acid segment of CA and the entire vif gene from simian immunodeficiency virus (SIV) was previously shown to establish spreading infections in cultured macaque peripheral blood mononuclear cells. To assess its replicative and disease-inducing properties in vivo, HIVNL-DT5R was inoculated into pig-tailed macaques. HIVNL-DT5R generated plasma viremia in all five of the monkeys and elicited humoral responses against all of the HIV-1 structural proteins but did not cause CD4+ T-lymphocyte depletion or clinical disease. Additional adaptation will be required to optimize infectivity in vivo.


1997 ◽  
Vol 41 (5) ◽  
pp. 1082-1093 ◽  
Author(s):  
S M Daluge ◽  
S S Good ◽  
M B Faletto ◽  
W H Miller ◽  
M H St Clair ◽  
...  

1592U89, (-)-(1S,4R)-4-[2-amino-6-(cyclopropylamino)-9H-purin-9-yl]-2-cyclo pentene-1-methanol, is a carbocyclic nucleoside with a unique biological profile giving potent, selective anti-human immunodeficiency virus (HIV) activity. 1592U89 was selected after evaluation of a wide variety of analogs containing a cyclopentene substitution for the 2'-deoxyriboside of natural deoxynucleosides, optimizing in vitro anti-HIV potency, oral bioavailability, and central nervous system (CNS) penetration. 1592U89 was equivalent in potency to 3'-azido-3'-deoxythymidine (AZT) in human peripheral blood lymphocyte (PBL) cultures against clinical isolates of HIV type 1 (HIV-1) from antiretroviral drug-naive patients (average 50% inhibitory concentration [IC50], 0.26 microM for 1592U89 and 0.23 microM for AZT). 1592U89 showed minimal cross-resistance (approximately twofold) with AZT and other approved HIV reverse transcriptase (RT) inhibitors. 1592U89 was synergistic in combination with AZT, the nonnucleoside RT inhibitor nevirapine, and the protease inhibitor 141W94 in MT4 cells against HIV-1 (IIIB). 1592U89 was anabolized intracellularly to its 5'-monophosphate in CD4+ CEM cells and in PBLs, but the di- and triphosphates of 1592U89 were not detected. The only triphosphate found in cells incubated with 1592U89 was that of the guanine analog (-)-carbovir (CBV). However, the in vivo pharmacokinetic, distribution, and toxicological profiles of 1592U89 were distinct from and improved over those of CBV, probably because CBV itself was not appreciably formed from 1592U89 in cells or animals (<2%). The 5'-triphosphate of CBV was a potent, selective inhibitor of HIV-1 RT, with Ki values for DNA polymerases (alpha, beta, gamma, and epsilon which were 90-, 2,900-, 1,200-, and 1,900-fold greater, respectively, than for RT (Ki, 21 nM). 1592U89 was relatively nontoxic to human bone marrow progenitors erythroid burst-forming unit and granulocyte-macrophage CFU (IC50s, 110 microM) and human leukemic and liver tumor cell lines. 1592U89 had excellent oral bioavailability (105% in the rat) and penetrated the CNS (rat brain and monkey cerebrospinal fluid) as well as AZT. Having demonstrated an excellent preclinical profile, 1592U89 has progressed to clinical evaluation in HIV-infected patients.


Blood ◽  
1992 ◽  
Vol 80 (8) ◽  
pp. 2128-2135 ◽  
Author(s):  
MP Busch ◽  
TH Lee ◽  
J Heitman

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.


2003 ◽  
Vol 77 (7) ◽  
pp. 4389-4395 ◽  
Author(s):  
Anuska Llano ◽  
Jordi Barretina ◽  
Arantxa Gutiérrez ◽  
Bonaventura Clotet ◽  
José A. Esté

ABSTRACT There is a relationship between CD4-T-cell number and circulating interleukin 7 (IL-7) levels in human immunodeficiency virus (HIV)-positive individuals. Here, we show that IL-7 induced a dose-dependent production of CCL3 (MIP-1α), CCL4 (MIP-1β), and CCL5 (RANTES) in peripheral blood mononuclear cells (PBMC), ex vivo tonsil lymphoid tissue of HIV− individuals, and PBMC from HIV+ individuals, suggesting that IL-7 may regulate β-chemokine production in vivo. In a cross-sectional study of HIV+ individuals (n = 130), a weak but significant correlation between IL-7 and RANTES was noted (r = 0.379; P < 0.001). Remarkably, the correlation between IL-7 and RANTES increased to an r value of 0.798 (P < 0.001) if individuals with low CD4 cell counts (<200 cells/μl) were excluded from the analysis. Our results suggest that there is a relationship between IL-7 and the production of RANTES both in vitro and in vivo that is lost in immune-compromised patients (CD4 count of <200 cells/μl) but that could be restored by antiretroviral therapy. Unlike the case for IL-7, high levels of RANTES suggest an intermediate stage of HIV disease progression.


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