This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Vatakis, D. N.
Right arrow Articles by Zack, J. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Vatakis, D. N.
Right arrow Articles by Zack, J. A.

 Previous Article  |  Next Article 

Journal of Virology, April 2009, p. 3374-3378, Vol. 83, No. 7
0022-538X/09/$08.00+0     doi:10.1128/JVI.02161-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Differentially Stimulated CD4+ T Cells Display Altered Human Immunodeficiency Virus Infection Kinetics: Implications for the Efficacy of Antiviral Agents{triangledown}

Dimitrios N. Vatakis,1,3 Christopher C. Nixon,2 Gregory Bristol,1,3 and Jerome A. Zack1,2,3*

David Geffen School of Medicine at UCLA, Department of Medicine, Division of Hematology/Oncology,1 Department of Microbiology Immunology and Molecular Genetics,2 UCLA AIDS Institute, Los Angeles, California 900953

Received 13 October 2008/ Accepted 2 January 2009


arrow
ABSTRACT
 
The activation state of CD4+ T cells plays a crucial role in the establishment of a productive human immunodeficiency virus infection. Here, we show that T cells stimulated for 1 day demonstrated delayed kinetics of viral reverse transcription and integration compared to cells stimulated for 2 days prior to infection. As a result, the efficiency of reverse transcription and integration inhibitors differs in these differentially stimulated cells. These studies increase our understanding of how T cells support viral replication and provide insight regarding the efficiency of antiretroviral therapy in lymphoid compartments.


arrow
TEXT
 
Unlike activated T cells, quiescent CD4+ T cells are resistant to human immunodeficiency virus (HIV) infection. Early studies showed that this block was characterized by the premature termination of reverse transcription (RT) (11, 12, 22, 25, 34, 35). Subsequent studies, using more-sensitive techniques, established that RT in quiescent cells was far slower and less stable than in activated cells (17, 36). In addition, we and others demonstrated that while cells activated for 48 h can be efficiently infected, infection prior to T-cell activation is very inefficient, characterized by a large delay in the kinetics of RT and integration, even if the cell is stimulated immediately following infection (11, 18, 27, 30). Therefore, the activation state of T cells markedly affects the progression of the early stages of HIV infection (29).

Nondividing cell types such as macrophages have been shown to be permissive to HIV infection (6, 14, 21, 24). Subsequent work showed that entry into the G1b phase of the cell cycle was sufficient to support the infection of T cells (11). Furthermore, it was demonstrated that various cytokine signals allowed infection in resting T cells (29). In vivo, T-cell activation generally occurs in lymphoid tissues, following the sequestration and presentation of foreign epitopes by antigen-presenting cells. HIV infection spreads via T-cell activation in these localized regions (1, 5). Within these regions, however, the relative state of T-cell activation is variable (5). Cells likely receive activation signals at different times relative to their exposure to virus.

To examine this issue, we stimulated quiescent CD4+ T cells for 24 or 48 h to generate target cells with different levels of activation. We then infected these cells with HIV and examined multiple stages of viral replication (RT, integration, viral gene transcription, and viral protein synthesis). Based on the kinetics of infection, we treated these differentially stimulated cells with RT and integration inhibitors to determine viral susceptibility.

Phenotype of quiescent CD4+ T cells stimulated for 24 or 48 h. Quiescent CD4+ T cells were isolated from total peripheral blood mononuclear cells by negative selection as previously described (30). This enabled us to stimulate a highly purified homogeneous population of truly quiescent CD4+ T cells. We then stimulated these cells for 24 or 48 h with plate-bound anti-CD3 (1 µg/ml) and soluble anti-CD28 (50 ng/ml). Cell cycle and activation states were assessed by flow cytometric assays (30) to examine cellular DNA and RNA synthesis, as well as the expression of T-cell activation markers (CD25, CD69, and HLA-DR). The cells stimulated for 24 h did not yet progress past the G1b phase of the cell cycle and expressed high levels of CD69 (Fig. 1). However, the 48-h-stimulated cells were distributed in all phases of the cell cycle and expressed high levels of all three activation markers, especially CD25 and HLA-DR (Fig. 1). Although 24-h stimulation was too early to produce robust cycling, these cells entered the G1b phase of the cell cycle, which we previously determined was sufficient for HIV infection (11).


Figure 1
View larger version (24K):
[in this window]
[in a new window]

  		FIG. 1. Activation state of quiescent CD4+ T cells activated for 1 or 2 days. Quiescent CD4+ T cells were purified and stimulated by plate-bound anti-CD3 and soluble anti-CD28. After stimulation, cells were suspended in a buffer containing 0.03% saponin (Sigma). Fifty microliters of 400 µM 7AAD (Calbiochem, La Jolla, CA) was added at a final concentration of 20 mM. The cells were incubated at room temperature for 30 min and cooled on ice for at least 5 min, and 3 µl of 1.7 mM PyroninY (Polysciences, Warrington, PA) was added at a final concentration of 5 µM; the cells were then incubated for an additional 10 min on ice and analyzed. The quadrants were set based on n-butyrate (G1a arrest) and aphidocolin (G1b arrest) treatment of these cells as previously described (11, 30). In addition, cells were stained for the expression of CD25, CD69, and HLA-DR. The red line represents quiescent cells, blue 24-h-stimulated cells, and green 48-h-stimulated cells.

Kinetics of HIV infection in 24- and 48-h-stimulated CD4+ T cells. Since a significant amount of 24-h-stimulated T cells were in a permissive state, it was of interest to examine the detailed kinetics of HIV infection compared to that of the 48-h-stimulated cells. Following stimulation, the cells were infected with HIVNL4-3 for 2 h (multiplicity of infection [MOI], 0.5) and cultured in the presence of the protease inhibitor indinavir (100 nM) to ensure a single-round infection. We first assessed the kinetics of RT by a quantitative real-time PCR as previously described (30). In the cells stimulated for 48 h prior to infection, full-length viral DNA began to appear 4 h postinfection and peaked at 12 h, while in the cells stimulated for 24 h, the completion of RT was delayed and became apparent 6 h postinfection, peaking at the 24-h time point (Fig. 2A and D). A similar delay in kinetics was observed when analyzing samples for the presence of integrated proviral DNA, as assessed by an Alu-based PCR integration assay (Fig. 2B and D) (15, 30). In the 48-h-stimulated group, integration peaked at 12 h postinfection, while in cells stimulated for 24 h, integration was seen at the 24-h time point. The differences in RT and integration are temporal rather than quantitative (difference of less than fivefold), as the absolute levels converged at later time points. Interestingly, both groups exhibited the accumulation of intracellular p24 Gag (assessed by intracellular staining (15, 30) 24 h postinfection, albeit at different amounts (Fig. 2C and D). Thus, 24-h stimulation rendered cells permissive to HIV infection.


Figure 2
View larger version (34K):
[in this window]
[in a new window]

  		FIG. 2. Kinetics of HIV infection in 1-day- and 2-day-stimulated CD4+ T cells. The data shown are a representative of the results from three independent experiments. Quiescent CD4+ T cells were isolated from peripheral blood mononuclear cells obtained from healthy human donors. The cells were stimulated for 1 or 2 days followed by infection with HIVNL4-3 (MOI, 0.5). Diamonds represent the 24-h-stimulated group and squares the 2-day-stimulated group, unless otherwise specified. (A) 0.3 x 106 cells were harvested at different time points after infection, and DNA was extracted for viral DNA analysis. DNA extraction and real-time PCR analysis were performed. The limit of detection (indicated by a dashed line) was 0.01% cells based on AZT-treated negative controls. (B) 0.3 x 106 cells were harvested at different time points after infection, and DNA was extracted for viral integration analysis. The integration of viral DNA was assessed by an Alu-based integration assay (15, 30). The limit of detection (indicated by a dashed line) was 0.01% cells. In the control experiments, there was no background from nonintegrated viral DNA and values for the integrated viral DNA varied less than 20% within triplicates. (C) Cells were harvested at different time points after infection and analyzed for intracellular p24 Gag expression by fluorescence-activated cell sorting. Intracellular staining was performed by membrane permeabilization, followed by staining with antibody to the KC57 epitope of p24 Gag. (D) A schematic diagram outlining the kinetics of infection in 24- and 48-h-stimulated quiescent CD4+ T cells.

Effect of the CD4+ T-cell activation state on the efficacy of antiretroviral drugs. The differences observed in HIV kinetics led us to examine the sensitivity of the above cell populations to antiretroviral drugs targeting the early stages in the viral life cycle. To address this, cells were treated with zidovudine (AZT) (10 µM), efavirenz (EFV) (0.1 µM) (4, 23, 33), or the integrase inhibitors 118-D-24 (80 µM) (26) and raltegravir (50 nM), which was recently approved for clinical use (8-10), at various time points postinfection. The inhibition of viral replication was assessed by quantifying intracellular p24 Gag levels 48 h postinfection. The response to AZT treatment correlated well with RT kinetics. AZT was effective at blocking infection in the 48-h-stimulated cells when added up to 6 h after infection (Fig. 3A). In contrast, in 24-h-stimulated cells, the drug was effective if added up to 12 h postinfection. In a separate set of experiments (Fig. 3B), we examined the effect of EFV compared to that of AZT. Although AZT and EFV inhibit RT, they function through different mechanisms, possibly leading to altered inhibition kinetics (4, 23, 33). However, there was no observed difference between the two RT inhibitors.


Figure 3
View larger version (18K):
[in this window]
[in a new window]

  		FIG. 3. Efficacy of RT inhibitor drugs on differentially stimulated cells infected with HIVNL4-3. Quiescent CD4+ T cells were stimulated for 1 day ({blacklozenge}) or 2 days ({blacksquare}), unless specified otherwise in the legend. Subsequently, they were infected with HIVNL4-3 (MOI, 0.5). The results are the average of four different experiments, unless otherwise indicated. In all experiments, infection was assessed 2 days later by p24 Gag expression using fluorescence-activated cell sorting and plotted as the percentage of inhibition. Statistically significant differences are indicated by asterisks (**, P < 0.05). Comparisons between multiple groups were made using the one-tailed Student t test. (A) Infected cells were treated with AZT at different time points after infection. The 24-h time point is the average of the results from two experiments. (B) Infected cells were treated with AZT or EFV at different time points after infection.

The effectiveness of the integrase inhibitors 118-D-24 and raltegravir (Fig. 4) reflected the kinetics of integration between the two cell populations. The drug effectiveness of 118-D-24 did not exceed 70% inhibition (as opposed to RT inhibitors, for which inhibition exceeded 90%). 118-D-24 added to cells stimulated for 24 h showed a significantly greater ability to inhibit integration when added 12 h postinfection than in cells stimulated for 48 h. However, in both cell types, the effect of the inhibitor was lost if added 14 h postinfection. On the other hand, the efficacy of raltegravir was far superior. Inhibition was more than 90% under both conditions. When added to cells stimulated for 24 h, the drug inhibited when added up to 12 h postinfection, while in 48-h-stimulated cells, some virus could escape inhibition at 8 h postinfection. Therefore, due to the delayed progression of viral replication, the 24-h-stimulated cells were susceptible to antiretroviral drugs over a longer period of time.


Figure 4
View larger version (19K):
[in this window]
[in a new window]

  		FIG. 4. Efficacy of integrase inhibitors on differentially stimulated cells infected with HIVNL4-3. Quiescent CD4+ T cells were stimulated for 1 day ({blacklozenge}) or 2 days ({blacksquare}), unless specified otherwise in the legend. Subsequently, they were infected with HIVNL4-3 (MOI, 0.5). The results are the average of four different experiments, unless otherwise indicated. In all experiments, infection was assessed 2 days later by p24 Gag expression using fluorescence-activated cell sorting and plotted as the percentage of inhibition. Statistically significant differences are indicated by asterisks (**, P < 0.05). Comparisons between multiple groups were made using the one-tailed Student t test. (A) Infected cells were treated with 118-D-24 at different time points after infection. (B) Infected cells were treated with raltegravir at different time points after infection.

In vivo CD4+ T cells are found in diverse anatomic locations such that the encounter with antigen or stimulating cytokines is not a homogeneous event. This results in different T-cell activation states in a single location (5, 16, 29). As a productive HIV infection is dependent on the target cell's activation state (11, 19, 25, 28, 30, 34), this has major implications for viral pathogenesis and therapy.

In this study, we determined the kinetics of HIV infection in differentially activated T cells. Cells stimulated for 24 h displayed a 12-h delay in RT and integration compared to the 48-h-stimulated cells. Interestingly, viral protein expression kinetics were similar in both cell populations. Therefore, the kinetics of the early stages of the viral life cycle may be modulated by host mechanisms, such as signal transduction pathways (3, 7, 19, 25, 32) or host cytoskeletal organization activated during T-cell activation (2, 13). T-cell activation may also change the patterns of HIV integration due to distinct cellular gene expression patterns (20, 31).

Based on the results above, we reasoned that antiretroviral drugs targeting viral RT and integration would have differential effects on the virus depending on the activation state of the host cell. Our data showed that the effective window for RT and integration inhibitors was increased for partially activated cells (the 24-h-stimulated group) compared with that for fully activated T cells (the 48-h-stimulated group). A similar trend was seen when we treated the two cell groups with integrase inhibitors.

These data clearly demonstrate that antiviral drug effectiveness is tightly linked to the rate of viral life cycle progression, which in turn is dependent on the cell activation state. Our data suggest that integration inhibitors, due to their prolonged period of efficacy, might be useful as postexposure prophylactic agents in circumstances such as known needlestick injuries. While these results do not reflect true in vivo drug efficacy, as dosing, availability, and metabolism may affect drug concentrations, a deeper understanding of the cellular mechanisms required for a productive infection can lead to the development of more potent therapies against HIV.


arrow
ACKNOWLEDGMENTS
 
We thank Helen J. Brown for critically reading the manuscript. The following reagents were obtained through the AIDS Research and Reference Reagent Program, Division of AIDS, NIAID, NIH: AZT, EFV, integrase inhibitor 118-D-24, and indinavir sulfate. Raltegravir was provided by Merck (Whitehouse Station, NJ).

This work was supported by NIH grants AI36059, AI03059, and AI070010 and the UCLA CFAR (AI28697).


arrow
FOOTNOTES
 
* Corresponding author. Mailing address: 615 Charles E. Young Drive South, BSRB 173 Mailcode: 736322, Los Angeles, CA 90095. Phone: (310) 825-0876. Fax: (310) 983-1067. E-mail: jzack{at}ucla.edu Back

{triangledown} Published ahead of print on 7 January 2009. Back


arrow
REFERENCES
 
    1
  1. Brenchley, J. M., B. J. Hill, D. R. Ambrozak, D. A. Price, F. J. Guenaga, J. P. Casazza, J. Kuruppu, J. Yazdani, S. A. Migueles, M. Connors, M. Roederer, D. C. Douek, and R. A. Koup. 2004. T-cell subsets that harbor human immunodeficiency virus (HIV) in vivo: implications for HIV pathogenesis. J. Virol. 78:1160-1168.[Abstract/Free Full Text]
    2. 2
  2. Bukrinskaya, A., B. Brichacek, A. Mann, and M. Stevenson. 1998. Establishment of a functional human immunodeficiency virus type 1 (HIV-1) reverse transcription complex involves the cytoskeleton. J. Exp. Med. 188:2113-2125.[Abstract/Free Full Text]
    3. 3
  3. Cole, S. W., Y. D. Korin, J. L. Fahey, and J. A. Zack. 1998. Norepinephrine accelerates HIV replication via protein kinase A-dependent effects on cytokine production. J. Immunol. 161:610-616.[Abstract/Free Full Text]
    4. 4
  4. De Clercq, E. 1998. The role of non-nucleoside reverse transcriptase inhibitors (NNRTIs) in the therapy of HIV-1 infection. Antivir. Res. 38:153-179.[CrossRef][Medline]
    5. 5
  5. Eckstein, D. A., M. L. Penn, Y. D. Korin, D. D. Scripture-Adams, J. A. Zack, J. F. Kreisberg, M. Roederer, M. P. Sherman, P. S. Chin, and M. A. Goldsmith. 2001. HIV-1 actively replicates in naive CD4(+) T cells residing within human lymphoid tissues. Immunity 15:671-682.[CrossRef][Medline]
    6. 6
  6. Embretson, J., M. Zupancic, J. L. Ribas, A. Burke, P. Racz, K. Tenner-Racz, and A. T. Haase. 1993. Massive covert infection of helper T lymphocytes and macrophages by HIV during the incubation period of AIDS. Nature 362:359-362.[CrossRef][Medline]
    7. 7
  7. Francois, F., and M. E. Klotman. 2003. Phosphatidylinositol 3-kinase regulates human immunodeficiency virus type 1 replication following viral entry in primary CD4+ T lymphocytes and macrophages. J. Virol. 77:2539-2549.[Abstract/Free Full Text]
    8. 8
  8. Hazuda, D. J., S. D. Young, J. P. Guare, N. J. Anthony, R. P. Gomez, J. S. Wai, J. P. Vacca, L. Handt, S. L. Motzel, H. J. Klein, G. Dornadula, R. M. Danovich, M. V. Witmer, K. A. Wilson, L. Tussey, W. A. Schleif, L. S. Gabryelski, L. Jin, M. D. Miller, D. R. Casimiro, E. A. Emini, and J. W. Shiver. 2004. Integrase inhibitors and cellular immunity suppress retroviral replication in rhesus macaques. Science 305:528-532.[Abstract/Free Full Text]
    9. 9
  9. Iwamoto, M., L. A. Wenning, A. S. Petry, M. Laethem, M. De Smet, J. T. Kost, S. A. Merschman, K. M. Strohmaier, S. Ramael, K. C. Lasseter, J. A. Stone, K. M. Gottesdiener, and J. A. Wagner. 2008. Safety, tolerability, and pharmacokinetics of raltegravir after single and multiple doses in healthy subjects. Clin. Pharmacol. Ther. 83:293-299.[CrossRef][Medline]
    10. 10
  10. Kassahun, K., I. McIntosh, D. Cui, D. Hreniuk, S. Merschman, K. Lasseter, N. Azrolan, M. Iwamoto, J. A. Wagner, and L. A. Wenning. 2007. Metabolism and disposition in humans of raltegravir (MK-0518), an anti-AIDS drug targeting the human immunodeficiency virus 1 integrase enzyme. Drug Metab. Dispos. 35:1657-1663.[Abstract/Free Full Text]
    11. 11
  11. Korin, Y. D., and J. A. Zack. 1998. Progression to the G1b phase of the cell cycle is required for completion of human immunodeficiency virus type 1 reverse transcription in T cells. J. Virol. 72:3161-3168.[Abstract/Free Full Text]
    12. 12
  12. Korin, Y. D., and J. A. Zack. 1999. Nonproductive human immunodeficiency virus type 1 infection in nucleoside-treated G0 lymphocytes. J. Virol. 73:6526-6532.[Abstract/Free Full Text]
    13. 13
  13. Matarrese, P., and W. Malorni. 2005. Human immunodeficiency virus (HIV)-1 proteins and cytoskeleton: partners in viral life and host cell death. Cell Death Differ. 12(Suppl. 1):932-941.[CrossRef][Medline]
    14. 14
  14. O'Brien, W. A., A. Namazi, H. Kalhor, S. H. Mao, J. A. Zack, and I. S. Chen. 1994. Kinetics of human immunodeficiency virus type 1 reverse transcription in blood mononuclear phagocytes are slowed by limitations of nucleotide precursors. J. Virol. 68:1258-1263.[Abstract/Free Full Text]
    15. 15
  15. O'Doherty, U., W. J. Swiggard, D. Jeyakumar, D. McGain, and M. H. Malim. 2002. A sensitive, quantitative assay for human immunodeficiency virus type 1 integration. J. Virol. 76:10942-10950.[Abstract/Free Full Text]
    16. 16
  16. Oswald-Richter, K., S. M. Grill, M. Leelawong, and D. Unutmaz. 2004. HIV infection of primary human T cells is determined by tunable thresholds of T cell activation. Eur. J. Immunol. 34:1705-1714.[CrossRef][Medline]
    17. 17
  17. Pierson, T. C., Y. Zhou, T. L. Kieffer, C. T. Ruff, C. Buck, and R. F. Siliciano. 2002. Molecular characterization of preintegration latency in human immunodeficiency virus type 1 infection. J. Virol. 76:8518-8531.[Abstract/Free Full Text]
    18. 18
  18. Plesa, G., J. Dai, C. Baytop, J. L. Riley, C. H. June, and U. O'Doherty. 2007. Addition of deoxynucleosides enhances human immunodeficiency virus type 1 integration and 2LTR formation in resting CD4+ T cells. J. Virol. 81:13938-13942.[Abstract/Free Full Text]
    19. 19
  19. Polacino, P. S., H. A. Liang, and E. A. Clark. 1995. Formation of simian immunodeficiency virus long terminal repeat circles in resting T cells requires both T cell receptor- and IL-2-dependent activation. J. Exp. Med. 182:617-621.[Abstract/Free Full Text]
    20. 20
  20. Schroder, A. R., P. Shinn, H. Chen, C. Berry, J. R. Ecker, and F. Bushman. 2002. HIV-1 integration in the human genome favors active genes and local hotspots. Cell 110:521-529.[CrossRef][Medline]
    21. 21
  21. Schuitemaker, H., N. A. Kootstra, R. A. Fouchier, B. Hooibrink, and F. Miedema. 1994. Productive HIV-1 infection of macrophages restricted to the cell fraction with proliferative capacity. EMBO J. 13:5929-5936.[Medline]
    22. 22
  22. Spina, C. A., J. C. Guatelli, and D. D. Richman. 1995. Establishment of a stable, inducible form of human immunodeficiency virus type 1 DNA in quiescent CD4 lymphocytes in vitro. J. Virol. 69:2977-2988.[Abstract]
    23. 23
  23. Staszewski, S., J. Morales-Ramirez, K. T. Tashima, A. Rachlis, D. Skiest, J. Stanford, R. Stryker, P. Johnson, D. F. Labriola, D. Farina, D. J. Manion, N. M. Ruiz, et al. 1999. Efavirenz plus zidovudine and lamivudine, efavirenz plus indinavir, and indinavir plus zidovudine and lamivudine in the treatment of HIV-1 infection in adults. N. Engl. J. Med. 341:1865-1873.[Abstract/Free Full Text]
    24. 24
  24. Stevenson, M., B. Brichacek, N. Heinzinger, S. Swindells, S. Pirruccello, E. Janoff, and M. Emerman. 1995. Molecular basis of cell cycle dependent HIV-1 replication. Implications for control of virus burden. Adv. Exp. Med. Biol. 374:33-45.[Medline]
    25. 25
  25. Stevenson, M., T. L. Stanwick, M. P. Dempsey, and C. A. Lamonica. 1990. HIV-1 replication is controlled at the level of T cell activation and proviral integration. EMBO J. 9:1551-1560.[Medline]
    26. 26
  26. Svarovskaia, E. S., R. Barr, X. Zhang, G. C. Pais, C. Marchand, Y. Pommier, T. R. Burke, Jr., and V. K. Pathak. 2004. Azido-containing diketo acid derivatives inhibit human immunodeficiency virus type 1 integrase in vivo and influence the frequency of deletions at two-long-terminal-repeat-circle junctions. J. Virol. 78:3210-3222.[Abstract/Free Full Text]
    27. 27
  27. Swiggard, W. J., C. Baytop, J. J. Yu, J. Dai, C. Li, R. Schretzenmair, T. Theodosopoulos, and U. O'Doherty. 2005. Human immunodeficiency virus type 1 can establish latent infection in resting CD4+ T cells in the absence of activating stimuli. J. Virol. 79:14179-14188.[Abstract/Free Full Text]
    28. 28
  28. Swiggard, W. J., U. O'Doherty, D. McGain, D. Jeyakumar, and M. H. Malim. 2004. Long HIV type 1 reverse transcripts can accumulate stably within resting CD4+ T cells while short ones are degraded. AIDS Res. Hum. Retrovir. 20:285-295.[CrossRef][Medline]
    29. 29
  29. Unutmaz, D., V. N. KewalRamani, S. Marmon, and D. R. Littman. 1999. Cytokine signals are sufficient for HIV-1 infection of resting human T lymphocytes. J. Exp. Med. 189:1735-1746.[Abstract/Free Full Text]
    30. 30
  30. Vatakis, D. N., G. Bristol, T. A. Wilkinson, S. A. Chow, and J. A. Zack. 2007. Immediate activation fails to rescue efficient human immunodeficiency virus replication in quiescent CD4+ T cells. J. Virol. 81:3574-3582.[Abstract/Free Full Text]
    31. 31
  31. Wang, G. P., A. Ciuffi, J. Leipzig, C. C. Berry, and F. D. Bushman. 2007. HIV integration site selection: analysis by massively parallel pyrosequencing reveals association with epigenetic modifications. Genome Res. 17:1186-1194.[Abstract/Free Full Text]
    32. 32
  32. Yang, X., and D. Gabuzda. 1999. Regulation of human immunodeficiency virus type 1 infectivity by the ERK mitogen-activated protein kinase signaling pathway. J. Virol. 73:3460-3466.[Abstract/Free Full Text]
    33. 33
  33. Young, S. D., S. F. Britcher, L. O. Tran, L. S. Payne, W. C. Lumma, T. A. Lyle, J. R. Huff, P. S. Anderson, D. B. Olsen, S. S. Carroll, et al. 1995. L-743, 726 (DMP-266): a novel, highly potent nonnucleoside inhibitor of the human immunodeficiency virus type 1 reverse transcriptase. Antimicrob. Agents Chemother. 39:2602-2605.[Abstract]
    34. 34
  34. Zack, J. A., S. J. Arrigo, S. R. Weitsman, A. S. Go, A. Haislip, and I. S. Chen. 1990. HIV-1 entry into quiescent primary lymphocytes: molecular analysis reveals a labile, latent viral structure. Cell 61:213-222.[CrossRef][Medline]
    35. 35
  35. Zack, J. A., A. M. Haislip, P. Krogstad, and I. S. Chen. 1992. Incompletely reverse-transcribed human immunodeficiency virus type 1 genomes in quiescent cells can function as intermediates in the retroviral life cycle. J. Virol. 66:1717-1725.[Abstract/Free Full Text]
    36. 36
  36. Zhou, Y., H. Zhang, J. D. Siliciano, and R. F. Siliciano. 2005. Kinetics of human immunodeficiency virus type 1 decay following entry into resting CD4+ T cells. J. Virol. 79:2199-2210.[Abstract/Free Full Text]

Journal of Virology, April 2009, p. 3374-3378, Vol. 83, No. 7
0022-538X/09/$08.00+0     doi:10.1128/JVI.02161-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Arfi, V., Lienard, J., Nguyen, X.-N., Berger, G., Rigal, D., Darlix, J.-L., Cimarelli, A. (2009). Characterization of the Behavior of Functional Viral Genomes during the Early Steps of Human Immunodeficiency Virus Type 1 Infection. J. Virol. 83: 7524-7535 [Abstract] [Full Text]  

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Vatakis, D. N.
Right arrow Articles by Zack, J. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Vatakis, D. N.
Right arrow Articles by Zack, J. A.

Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»