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Freeman TL, Zhao C, Schrode N, Fortune T, Shroff S, Tweel B, Beaumont KG, Swartz TH. HIV-1 activates oxidative phosphorylation in infected CD4 T cells in a human tonsil explant model. Front Immunol 2023; 14:1172938. [PMID: 37325659 PMCID: PMC10266353 DOI: 10.3389/fimmu.2023.1172938] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 05/16/2023] [Indexed: 06/17/2023] Open
Abstract
Introduction Human immunodeficiency virus type 1 (HIV-1) causes a chronic, incurable infection leading to immune activation and chronic inflammation in people with HIV-1 (PWH), even with virologic suppression on antiretroviral therapy (ART). The role of lymphoid structures as reservoirs for viral latency and immune activation has been implicated in chronic inflammation mechanisms. Still, the specific transcriptomic changes induced by HIV-1 infection in different cell types within lymphoid tissue remain unexplored. Methods In this study, we utilized human tonsil explants from healthy human donors and infected them with HIV-1 ex vivo. We performed single-cell RNA sequencing (scRNA-seq) to analyze the cell types represented in the tissue and to investigate the impact of infection on gene expression profiles and inflammatory signaling pathways. Results Our analysis revealed that infected CD4+ T cells exhibited upregulation of genes associated with oxidative phosphorylation. Furthermore, macrophages exposed to the virus but uninfected showed increased expression of genes associated with the NLRP3 inflammasome pathway. Discussion These findings provide valuable insights into the specific transcriptomic changes induced by HIV-1 infection in different cell types within lymphoid tissue. The activation of oxidative phosphorylation in infected CD4+ T cells and the proinflammatory response in macrophages may contribute to the chronic inflammation observed in PWH despite ART. Understanding these mechanisms is crucial for developing targeted therapeutic strategies to eradicate HIV-1 infection in PWH.
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Affiliation(s)
- Tracey L. Freeman
- Medical Scientist Training Program, University of Pittsburgh-Carnegie Mellon University, Pittsburgh, PA, United States
| | - Connie Zhao
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Nadine Schrode
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Trinisia Fortune
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Sanjana Shroff
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Benjamin Tweel
- Department of Otolaryngology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Kristin G. Beaumont
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Talia H. Swartz
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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2
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Abstract
The lack of a human immunodeficiency virus (HIV) cure has heightened interest in immunotherapy. As such, type I interferons (IFNs), in particular, IFN alpha (IFN-α), have gained renewed attention. However, HIV pathogenesis is driven by sustained IFN-mediated immune activation, and the use of IFNs is rather controversial. The following questions therein remain: (i) which IFN-α subtype to use, (ii) at which regimen, and (iii) at what time point in HIV infection it might be beneficial. Here, we used IFN-α14 modified by PASylation for its long half-life in vivo to eventually treat HIV infection. We defined the IFN dosing regimen based on the maximum increase in interferon-stimulated gene (ISG) expression 6 h after its administration and a return to baseline of ubiquitin-specific protease 18 (USP18) prior to the next dose. Notably, USP18 is the major negative regulator of type I IFN signaling. HIV infection resulted in increased ISG expression levels in humanized mice. Intriguingly, high baseline ISG levels correlated with lower HIV load. No effect was observed on HIV replication when PASylated IFN-α14 was administered in the chronic phase. However, combined antiretroviral therapy (cART) restored responsiveness to IFN, and PASylated IFN-α14 administered during analytical cART interruption resulted in a transiently lower HIV burden than in the mock-treated mice. In conclusion, cART-mediated HIV suppression restored transient IFN responsiveness and provided a potential window for immunoenhancing therapies in the context of analytical cART interruption. IMPORTANCE cART is highly efficient in suppressing HIV replication in HIV-infected patients and has resulted in a dramatic reduction in morbidity and mortality in HIV-infected people, yet it does not cure HIV infection. In addition, cART has several disadvantages. Thus, the HIV research community is exploring novel ways to control HIV infection for longer periods without cART. Here, we explored novel, long-acting IFN-α14 for its efficacy to control HIV replication in HIV-infected humanized mice. We found that IFN-α14 had no effect on chronic HIV infection. However, when mice were treated first with cART, we observed a transiently restored responsiveness to INF and a transiently lower HIV burden after stopping cART. These data emphasize (i) the value of cART-mediated HIV suppression and immune reconstitution in creating a window of opportunity for exploring novel immunotherapies, (ii) the potential of IFNs for constraining HIV, and (iii) the value of humanized mice for exploring novel immunotherapies.
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Reyes-Rodriguez AL, Reuter MA, McDonald D. Dendritic Cells Enhance HIV Infection of Memory CD4(+) T Cells in Human Lymphoid Tissues. AIDS Res Hum Retroviruses 2016; 32:203-10. [PMID: 26651015 DOI: 10.1089/aid.2015.0235] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Dendritic cells (DCs) play a key role in controlling infections by coordinating innate and adaptive immune responses to invading pathogens. Paradoxically, DCs can increase HIV-1 dissemination in vitro by binding and transferring infectious virions to CD4(+) T cells, a process called transinfection. Transinfection has been well characterized in cultured cell lines and circulating primary T cells, but it is unknown whether DCs enhance infection of CD4(+) T cells in vivo. In untreated HIV infection, massive CD4(+) T-cell infection and depletion occur in secondary lymphoid tissues long before decline is evident in the peripheral circulation. To study the role of DCs in HIV infection of lymphoid tissues, we utilized human tonsil tissues, cultured either as tissue blocks or as aggregate suspension cultures, in single-round infection experiments. In these experiments, addition of monocyte-derived DCs (MDDCs) to the cultures increased T-cell infection, particularly in CD4(+) T cells expressing lower levels of HLA-DR. Subset analysis demonstrated that MDDCs increased HIV-1 infection of central and effector memory T-cell populations. Depletion of endogenous myeloid DCs (myDCs) from the cultures decreased memory T-cell infection, and readdition of MDDCs restored infection to predepletion levels. Using an HIV-1 fusion assay, we found that MDDCs equally increased HIV delivery into naïve, central, and effector memory T cells in the cultures, whereas predepletion of myDCs reduced fusion into memory T cells. Together, these data suggest that resident myDCs facilitate memory T-cell infection in lymphoid tissues, implicating DC-mediated transinfection in driving HIV dissemination within these tissues in untreated HIV/AIDS.
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Affiliation(s)
- Angel L. Reyes-Rodriguez
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Morgan A. Reuter
- Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - David McDonald
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio
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4
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Li D, Schlaepfer E, Audigé A, Rochat MA, Ivic S, Knowlton CN, Kim B, Keppler OT, Speck RF. Vpx mediated degradation of SAMHD1 has only a very limited effect on lentiviral transduction rate in ex vivo cultured HSPCs. Stem Cell Res 2015. [PMID: 26207584 PMCID: PMC4766840 DOI: 10.1016/j.scr.2015.06.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Understanding how to achieve efficient transduction of hematopoietic stem and progenitor cells (HSPCs), while preserving their long-term ability to self-reproduce, is key for applying lentiviral-based gene engineering methods. SAMHD1 is an HIV-1 restriction factor in myeloid and resting CD4+ T cells that interferes with reverse transcription by decreasing the nucleotide pools or by its RNase activity. Here we show that SAMHD1 is expressed at high levels in HSPCs cultured in a medium enriched with cytokines. Thus, we hypothesized that degrading SAMHD1 in HSPCs would result in more efficient lentiviral transduction rates. We used viral like particles (VLPs) containing Vpx, shRNA against SAMHD1, or provided an excess of dNTPs or dNs to study this question. Regardless of the method applied, we saw no increase in the lentiviral transduction rate. The result was different when we used viruses (HR-GFP-Vpx+) which carry Vpx and encode GFP. These viruses allow assessment of the effects of Vpx specifically in the transduced cells. Using HR-GFP-Vpx+ viruses, we observed a modest but significant increase in the transduction efficiency. These data suggest that SAMHD1 has some limited efficacy in blocking reverse transcription but the major barrier for efficient lentiviral transduction occurs before reverse transcription.
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Affiliation(s)
- Duo Li
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, 8091, Switzerland.
| | - Erika Schlaepfer
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, 8091, Switzerland
| | - Annette Audigé
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, 8091, Switzerland
| | - Mary-Aude Rochat
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, 8091, Switzerland
| | - Sandra Ivic
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, 8091, Switzerland
| | - Caitlin N Knowlton
- Center for Drug Discovery, Department of Pediatrics, Emory University, Atlanta, GA 30322, USA
| | - Baek Kim
- Center for Drug Discovery, Department of Pediatrics, Emory University, Atlanta, GA 30322, USA
| | - Oliver T Keppler
- Institute of Medical Virology, National Reference Center for Retroviruses, University of Frankfurt, Frankfurt am Main 60054, Germany
| | - Roberto F Speck
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, 8091, Switzerland.
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5
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Adding new dimensions: towards an integrative understanding of HIV-1 spread. Nat Rev Microbiol 2014; 12:563-74. [PMID: 25029025 DOI: 10.1038/nrmicro3309] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In vitro studies in primary or immortalized cells continue to be used to elucidate the essential principles that govern the interactions between HIV-1 and isolated target cells. However, until recently, substantial technical barriers prevented this information from being efficiently translated to the more complex scenario of HIV-1 spread in the host in vivo, which has limited our understanding of the impact of host physiological parameters on the spread of HIV-1. In this Review, we discuss the recent development of imaging approaches to visualize HIV-1 spread and the adaptation of these approaches to organotypic ex vivo models and animal models. We focus on new concepts, including the mechanisms and in vivo relevance of cell-cell transmission for HIV-1 spread and the function of the HIV-1 pathogenesis factor Nef, which have emerged from the application of these integrative approaches in complex cell systems.
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Triggering TLR2, -3, -4, -5, and -8 reinforces the restrictive nature of M1- and M2-polarized macrophages to HIV. J Virol 2014; 88:9769-81. [PMID: 24942590 DOI: 10.1128/jvi.01053-14] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
UNLABELLED Macrophages must react to a large number of pathogens and their effects. In chronic HIV infection, the microenvironment changes with an influx of microbial products that trigger Toll-like receptors (TLRs). That dynamic nature can be replicated ex vivo by the proinflammatory (M1-polarized) and alternatively activated (M2-polarized) macrophages. Thus, we determined how polarized macrophages primed by various TLR agonists support HIV replication. Triggering of TLR2, -3, -4, -5, and -8 reinforced the low level of permissiveness in polarized macrophages. HIV was inhibited even more in M1-polarized macrophages than in macrophages activated only by TLR agonists. HIV was inhibited before its integration into the host chromosome. Polarization and triggering by various TLR agonists resulted in distinct cytokine profiles, endocytic activity, and distinct upregulation of restriction factors of HIV. Thus, different mechanisms likely contribute to the HIV-inhibitory effects. In chronic HIV infection, macrophages might become less permissive to HIV due to changes in the microenvironment. The high level of reactivity of polarized macrophages to TLR triggering may be exploited for immunotherapeutic strategies. IMPORTANCE Macrophages are a major target of HIV-1 infection. Different cell types in this very heterogeneous cell population respond differently to stimuli. In vitro, the heterogeneity is mimicked by their polarization into proinflammatory and alternatively activated macrophages. Here we explored the extent to which agonists triggering the TLR family affect HIV replication in polarized macrophages. We found that a number of TLR agonists blocked HIV replication substantially when given before infection. We also report the mechanisms of how TLR agonists exert their inhibitory action. Our findings may advance our understanding of which and how TLR agonists block HIV infection in polarized macrophages and may facilitate the design of novel immunotherapeutic approaches.
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Evans VA, Khoury G, Saleh S, Cameron PU, Lewin SR. HIV persistence: chemokines and their signalling pathways. Cytokine Growth Factor Rev 2012; 23:151-7. [PMID: 22749173 DOI: 10.1016/j.cytogfr.2012.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Latently infected resting CD4+ T cells are the major barrier to curing HIV. We have recently demonstrated that chemokines, which bind to the chemokine receptors CCR7, CXCR3 and CCR6, facilitate efficient HIV nuclear localisation and integration in resting CD4+ T cells, leading to latency. As latently infected cells are enriched in lymphoid tissues, where chemokines are highly concentrated, this may provide a mechanism for the generation of latently infected cells in vivo. Here we review the role of chemokines in HIV persistence; the main signalling pathways that are involved; and how these pathways may be exploited to develop novel strategies to reduce or eliminate latently infected cells.
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Affiliation(s)
- Vanessa A Evans
- Department of Medicine, Monash University, Melbourne, 3004, Australia
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8
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Audigé A, Hofer U, Dittmer U, van den Broek M, Speck RF. Evaluation of the immunomodulatory and antiviral effects of the cytokine combination IFN-α and IL-7 in the lymphocytic choriomeningitis virus and Friend retrovirus mouse infection models. Viral Immunol 2011; 24:375-85. [PMID: 21929334 DOI: 10.1089/vim.2011.0006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Existing therapies for chronic viral infections are still suboptimal or have considerable side effects, so new therapeutic strategies need to be developed. One option is to boost the host's immune response with cytokines. We have recently shown in an acute ex vivo HIV infection model that co-administration of interferon (IFN)-α and interleukin (IL)-7 allows us to combine the potent anti-HIV activity of IFN-α with the beneficial effects of IL-7 on T-cell survival and function. Here we evaluated the effect of combining IFN-α and IL-7 on viral replication in vivo in the chronic lymphocytic choriomeningitis virus (LCMV) and acute Friend retrovirus (FV) infection models. In the chronic LCMV model, cytokine treatment was started during the early replication phase (i.e., on day 7 post-infection [pi]). Under the experimental conditions used, exogenous IFN-α inhibited FV replication, but had no effect on viral replication in the LCMV model. There was no therapeutic benefit of IL-7 either alone or in combination with IFN-α in either of the two infection models. In the LCMV model, dose-dependent effects of the cytokine combination on T-cell phenotype/function were observed. It is possible that these effects would translate into antiviral activity in re-challenged mice. It is also possible that another type of IFN-α/β or induction of endogenous IFN-α/β alone or in combination with IL-7 would have antiviral activity in the LCMV model. Furthermore, we cannot exclude that some effect on viral titers would have been seen at later time points not investigated here (i.e., beyond day 34 pi). Finally, IFN-α/IL-7 may inhibit the replication of other viruses. Thus it might be worth testing these cytokines in other in vivo models of chronic viral infections.
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Affiliation(s)
- Annette Audigé
- Division of Infectious Diseases and Hospital Epidemiology, University of Zurich, Zurich, Switzerland.
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9
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Schlaepfer E, Speck RF. TLR8 Activates HIV from Latently Infected Cells of Myeloid-Monocytic Origin Directly via the MAPK Pathway and from Latently Infected CD4+T Cells Indirectly via TNF-α. THE JOURNAL OF IMMUNOLOGY 2011; 186:4314-24. [DOI: 10.4049/jimmunol.1003174] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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10
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Lewin SR, Evans VA, Elliott JH, Spire B, Chomont N. Finding a cure for HIV: will it ever be achievable? J Int AIDS Soc 2011; 14:4. [PMID: 21255462 PMCID: PMC3037295 DOI: 10.1186/1758-2652-14-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Accepted: 01/24/2011] [Indexed: 12/03/2022] Open
Abstract
Combination antiretroviral therapy (cART) has led to a major reduction in HIV-related mortality and morbidity. However, HIV still cannot be cured. With the absence of an effective prophylactic or therapeutic vaccine, increasing numbers of infected people, emerging new toxicities secondary to cART and the need for life-long treatment, there is now a real urgency to find a cure for HIV. There are currently multiple barriers to curing HIV. The most significant barrier is the establishment of a latent or "silent" infection in resting CD4+ T cells. In latent HIV infection, the virus is able to integrate into the host cell genome, but does not proceed to active replication. As a consequence, antiviral agents, as well as the immune system, are unable to eliminate these long-lived, latently infected cells. Reactivation of latently infected resting CD4+ T cells can then re-establish infection once cART is stopped. Other significant barriers to cure include residual viral replication in patients receiving cART, even when the virus is not detectable by conventional assays. In addition, HIV can be sequestered in anatomical reservoirs, such as the brain, gastrointestinal tract and genitourinary tract. Achieving either a functional cure (long-term control of HIV in the absence of cART) or a sterilizing cure (elimination of all HIV-infected cells) remains a major challenge. Several studies have now demonstrated that treatment intensification appears to have little impact on latent reservoirs. Some potential and promising approaches that may reduce the latent reservoir include very early initiation of cART and the use of agents that could potentially reverse latent infection. Agents that reverse latent infection will promote viral production; however, simultaneous administration of cART will prevent subsequent rounds of viral replication. Such drugs as histone deacetylase inhibitors, currently used and licensed for the treatment of some cancers, or activating latently infected resting cells with cytokines, such as IL-7 or prostratin, show promising results in reversing latency in vitro when used either alone or in combination. In order to move forward toward clinical trials that target eradication, there needs to be careful consideration of the risks and benefits of these approaches, agreement on the most informative endpoints for eradication studies and greater engagement of the infected community.
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Affiliation(s)
- Sharon R Lewin
- Department of Medicine, Monash University, Melbourne, Australia.
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Tsuchimoto T, Sakata KI, Someya M, Yamamoto H, Hirayama R, Matsumoto Y, Furusawa Y, Hareyama M. Gene expression associated with DNA-dependent protein kinase activity under normoxia, hypoxia, and reoxygenation. JOURNAL OF RADIATION RESEARCH 2011; 52:464-471. [PMID: 21905307 DOI: 10.1269/jrr.10137] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Affiliation(s)
- Tadashi Tsuchimoto
- Department of Radiology, Sapporo Medical University, School of Medicine, Hokkaido, Japan
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12
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Geuenich S, Kaderali L, Allespach I, Sertel S, Keppler OT. Biological signature characteristics of primary isolates from human immunodeficiency virus type 1 group O in ex vivo human tonsil histocultures. J Virol 2009; 83:10494-503. [PMID: 19706709 PMCID: PMC2753123 DOI: 10.1128/jvi.00928-09] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2009] [Accepted: 07/30/2009] [Indexed: 01/09/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) group M viruses have achieved a global distribution, while HIV-1 group O viruses are endemic only in particular regions of Africa. Here, we evaluated biological characteristics of group O and group M viruses in ex vivo models of HIV-1 infection. The replicative capacity and ability to induce CD4 T-cell depletion of eight group O and seven group M primary isolates were monitored in cultures of human peripheral blood mononuclear cells and tonsil explants. Comparative and longitudinal infection studies revealed HIV-1 group-specific activity patterns: CCR5-using (R5) viruses from group M varied considerably in their replicative capacity but showed similar levels of cytopathicity. In contrast, R5 isolates from group O were relatively uniform in their replicative fitness but displayed a high and unprecedented variability in their potential to deplete CD4 T cells. Two R5 group O isolates were identified that cause massive depletion of CD4 T cells, to an extent comparable to CXCR4-using viruses and not documented for any R5 isolate from group M. Intergroup comparisons found a five- to eightfold lower replicative fitness of isolates from group O than for isolates from group M yet a similar overall intrinsic pathogenicity in tonsil cultures. This study establishes biological ex vivo characteristics of HIV-1 group O primary isolates. The current findings challenge the belief that a grossly reduced replicative fitness or inherently impaired cytopathicity of viruses from this group underlies their low global prevalence.
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Affiliation(s)
- Silvia Geuenich
- Department of Virology, University of Heidelberg, Heidelberg, Germany
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Homann S, Tibroni N, Baumann I, Sertel S, Keppler OT, Fackler OT. Determinants in HIV-1 Nef for enhancement of virus replication and depletion of CD4+ T lymphocytes in human lymphoid tissue ex vivo. Retrovirology 2009; 6:6. [PMID: 19146681 PMCID: PMC2630989 DOI: 10.1186/1742-4690-6-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Accepted: 01/15/2009] [Indexed: 12/28/2022] Open
Abstract
Background HIV-1 Nef critically contributes to AIDS in part by augmenting virus titers in infected individuals. Analyzing which of Nef's activities contribute to HIV pathogenesis has been hampered by the lack of a cell culture model in which Nef exerts pronounced effects on HIV replication. The human lymphoid aggregate culture (HLAC) from tonsil maintains the cell populations and cytokine milieu found in vivo, supports a productive infection without exogenous stimulation, and Nef contributes to efficient HIV-1 replication as well as CD4+ T cell depletion in this experimental ex vivo-model. Results To identify determinants in Nef that mediate these activities, we infected HLAC with a panel of isogenic HIV-1NL4-3 strains that encode for well-characterized mutants of HIV-1SF2 Nef. Determination of HIV-1 replication revealed that enhancement of the virus spread by Nef is governed by a complex set of protein interaction surfaces. In contrast, increased CD4+ T lymphocyte depletion depended on only two protein interaction surfaces in Nef that mediate either downregulation of cell surface CD4 or interaction with the NAKC signalosome. Consistently, in HLAC from 9 out of 14 donors, Nef enhanced CD4+ T cell depletion in the absence of a significant effect on virus replication. Moreover, our results suggest that this Nef-dependent enhancement in depletion occurred predominately in uninfected bystander CD4+ T cells. Conclusion Our findings suggest that Nef facilitates depletion of CD4+ T lymphocytes in HIV-1-infected lymphoid tissue ex vivo by increasing the pool of productively infected cells and by sensitizing bystander cells for killing. This ability might contribute to Nef's pathogenic potential in vivo.
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14
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Audigé A, Urosevic M, Schlaepfer E, Walker R, Powell D, Hallenberger S, Joller H, Simon HU, Dummer R, Speck RF. Anti-HIV state but not apoptosis depends on IFN signature in CD4+ T cells. THE JOURNAL OF IMMUNOLOGY 2006; 177:6227-37. [PMID: 17056552 DOI: 10.4049/jimmunol.177.9.6227] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
To gain insights into the molecular mechanisms underlying early host responses to HIV in the CD4(+) T cell target population, we examined gene expression in CD4(+) T cells isolated 24 h after ex vivo HIV infection of lymphocyte aggregate cultures derived from human tonsils. Gene profiling showed a distinct up-regulation of genes related to immune response and response to virus, notably of IFN-stimulated genes (ISGs), irrespective of the coreceptor tropism of the virus. This mostly IFN-alpha-dependent gene signature suggested the involvement of plasmacytoid dendritic cells, a principal component of the antiviral immune response. Indeed, depletion of plasmacytoid dendritic cells before HIV inoculation abrogated transcriptional up-regulation of several ISGs and resulted in increased levels of HIV replication. Treatment with a blocking anti-IFN-alphaR Ab yielded increased HIV replication; conversely, HIV replication was decreased in pDC-depleted cultures treated with IFN-alpha. Among up-regulated ISGs was also TRAIL, indicating a potential role of the IFN signature in apoptosis. However, a blocking anti-TRAIL Ab did not abrogate apoptosis of CD4(+) T cells in CXCR4-tropic HIV-infected cultures, suggesting the involvement of pathways other than TRAIL mediated. We conclude that acute HIV infection of lymphoid tissue results in up-regulation of ISGs in CD4(+) T cells, which induces an anti-HIV state but not apoptosis.
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Affiliation(s)
- Annette Audigé
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, Raemistrasse 100, 8091 Zurich, Switzerland
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15
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Moutsopoulos NM, Vázquez N, Greenwell-Wild T, Ecevit I, Horn J, Orenstein J, Wahl SM. Regulation of the tonsil cytokine milieu favors HIV susceptibility. J Leukoc Biol 2006; 80:1145-55. [PMID: 16943383 DOI: 10.1189/jlb.0306142] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Mucosal associated lymphoid tissues are major targets of HIV during early infection and disease progression but can also provide a viral safe haven during highly active antiretroviral therapy. Among these tissues, the tonsils remain enigmatic regarding their status as primary and/or secondary sites of retroviral infection. To dissect the mechanisms underlying susceptibility to HIV in this compartment, isolated tonsil cells were studied for phenotypic and functional characteristics, which may account for their permissiveness to infection. For this, tonsil cells and PBMC were infected in parallel with HIV, and viral replication was monitored by p24 ELISA. Our results demonstrate that unstimulated tonsil cells were more readily infected than PBMC with HIV. Phenotypic characterization of the tonsil cells revealed heterogeneous lymphoid populations but with increased expression of early activation markers and the viral co-receptor CXCR4, relative to PBMC, all of which may contribute to viral susceptibility. Furthermore, the cytokine microenvironment appeared to be key in facilitating HIV infection and tonsil-secreted products enhanced HIV infection in PBMC. Of the cytokines detected in the tonsil supernatants, TH2 cytokines, particularly IL-4, promoted HIV infection and replication. Interestingly, this TH2 profile appeared to dominate, even in the presence of the TH1 cytokine IFNgamma and the anti-viral factor IFNalpha, likely due to the enhanced expression of suppressor of cytokine signaling (SOCS) proteins, which may disengage IFN signaling. These and other local environmental factors may render tonsil cells increasingly susceptible to HIV infection.
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Affiliation(s)
- Niki M Moutsopoulos
- Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, NIH, 30 Convent Dr., MSC 4352, Bethesda, MD 20892, USA
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Kreisberg JF, Yonemoto W, Greene WC. Endogenous factors enhance HIV infection of tissue naive CD4 T cells by stimulating high molecular mass APOBEC3G complex formation. ACTA ACUST UNITED AC 2006; 203:865-70. [PMID: 16606671 PMCID: PMC2118295 DOI: 10.1084/jem.20051856] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Human immunodeficiency virus (HIV) can infect resting CD4 T cells residing in lymphoid tissues but not those circulating in peripheral blood. The molecular mechanisms producing this difference remain unknown. We explored the potential role of the tissue microenvironment and its influence on the action of the antiviral factor APOBEC3G (A3G) in regulating permissivity to HIV infection. We found that endogenous IL-2 and -15 play a key role in rendering resident naive CD4 T cells susceptible to HIV infection. Infection of memory CD4 T cells also requires endogenous soluble factors, but not IL-2 or -15. A3G is found in a high molecular mass complex in HIV infection–permissive, tissue-resident naive CD4 T cells but resides in a low molecular mass form in nonpermissive, blood-derived naive CD4 T cells. Upon treatment with endogenous soluble factors, these cells become permissive for HIV infection, as low molecular mass A3G is induced to assemble into high molecular mass complexes. These findings suggest that in lymphoid tissues, endogenous soluble factors, likely including IL-2 and -15 and others, stimulate the formation of high molecular mass A3G complexes in tissue-resident naive CD4 T cells, thereby relieving the potent postentry restriction block for HIV infection conferred by low molecular mass A3G.
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Affiliation(s)
- Jason F Kreisberg
- Gladstone Institute of Virology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
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Song W, Wilson CM, Allen S, Wang C, Li Y, Kaslow RA, Tang J. Interleukin 18 and human immunodeficiency virus type I infection in adolescents and adults. Clin Exp Immunol 2006; 144:117-24. [PMID: 16542373 PMCID: PMC1809636 DOI: 10.1111/j.1365-2249.2006.03050.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2006] [Indexed: 12/21/2022] Open
Abstract
Interleukin (IL)-18, a proinflammatory cytokine, has been recognized recently as an important factor in both treated and untreated patients with human immunodeficiency virus type 1 (HIV-1) infection. Consistent with all earlier reports, our quantification of serum IL-18 concentrations in 88 HIV-1 seropositive, North American adolescents (14-18 years old) revealed a positive correlation with cell-free HIV-1 viral load at two separate visits (Spearman's r = 0.31 and 0.50, respectively, P < 0.01 for both), along with a negative correlation with CD4+ T cell counts (r = -0.31 and -0.35, P < 0.01 for both). In additional analyses of 66 adults (21-58 years old) from Zambia, HIV-1 seroconversion was associated uniformly with elevated IL-18 production (P < 0.0001). These epidemiological relationships were independent of other population-related characteristics, including age, gender and ethnicity. In neither study population could serum IL-18 concentrations be associated with the IL-18 gene (IL18) promoter genotypes defined by five major single nucleotide polymorphisms. Collectively, these findings suggest that circulating IL-18 rather than the IL18 genotype may provide a useful biomarker for HIV-1-related events or outcomes.
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Affiliation(s)
- W Song
- Department of Epidemiology, University of Alabama at Birmingham, Birmingham, AL 35294-0022, USA
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18
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Schlaepfer E, Audigé A, Joller H, Speck RF. TLR7/8 Triggering Exerts Opposing Effects in Acute versus Latent HIV Infection. THE JOURNAL OF IMMUNOLOGY 2006; 176:2888-95. [PMID: 16493046 DOI: 10.4049/jimmunol.176.5.2888] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
TLRs trigger innate immunity by recognizing conserved motifs of microorganisms. Recently, ssRNAs from HIV and influenza virus were shown to trigger TLR7 and 8. Thus, we hypothesized that HIV ssRNA, by triggering TLR7/8, affects HIV pathogenesis. Indeed, HIV ssRNA rendered human lymphoid tissue of tonsillar origin or PBMC barely permissive to HIV replication. The synthetic compound R-848, which also triggers TLR7/8, showed similar anti-HIV activity. Loss of R-848's activity in lymphoid tissue depleted of B cells suggested a role for B cells in innate immunity. TLR7/8 triggering appears to exert antiviral effects through soluble factors: conditioned medium reduced HIV replication in indicator cells. Although a number of cytokines and chemokines were increased upon adding R-848 to lymphoid tissue, blocking those cytokines/chemokines (i.e., IFN-alpha receptor, IFN-gamma, MIP-1alpha, -1beta, RANTES, and stromal cell-derived factor-1) did not result in the reversal of R-848's anti-HIV activity. Thus, the nature of this soluble factor(s) remains unknown. Unlike lymphoid tissue acutely infected with HIV, triggering latently infected promonocytic cells induced the release of HIV virions. The anti-HIV effects of triggering TLR7/8 may inhibit rapid killing, while pro-HIV effects may guarantee a certain replication level. Compounds triggering TLR7/8 may be attractive drug candidates to purge latent HIV while preventing new infections.
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Affiliation(s)
- Erika Schlaepfer
- Division of Infectious Diseases and Hospital Epidemiology, Department of Internal Medicine, University Hospital of Zurich, Zurich, Switzerland
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19
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Budhia S, Haring LF, McConnell I, Blacklaws BA. Quantitation of ovine cytokine mRNA by real-time RT–PCR. J Immunol Methods 2006; 309:160-72. [PMID: 16458919 DOI: 10.1016/j.jim.2005.12.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2004] [Revised: 08/31/2005] [Accepted: 12/07/2005] [Indexed: 11/23/2022]
Abstract
In this study we describe for the first time the dynamics of the expression of the cytokines, IL-1beta, IL-12p40, TNFalpha in ovine dendritic cells and macrophages after LPS stimulation. Real time RT-PCR was used for the quantitation of these cytokines and IL-4 and IFNgamma as well as two potential housekeeping genes (HKG), ATPase and GAPDH, in mRNAs from ovine leucocyte populations. Both dual-labelled probes (TAMRA/FAM) and SYBR Green assays were utilised, using a Corbett Research RotorGene and ABI 7700 machine. In order to quantitate each cytokine in our assays all C(T) values were compared to a standard curve generated using plasmid DNA containing the cytokine of interest. To validate our assays, concanavalin A-stimulated peripheral blood mononuclear cells (PBMCs) and LPS-stimulated monocyte-derived dendritic cells (MoDC) and monocyte-derived macrophages (MDMØ) were examined. We found that peak cytokine mRNA expression was between 3 and 6 h for the cytokines examined except for IL-12p40 where peak cytokine release was around 12 h post-stimulation in MDMØ and PBMCs. However, in MoDCs, peak IL-12p40 mRNA expression was observed within 3-6 h. We have identified a sensitive and reliable method for the identification of ovine cytokine mRNAs.
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Affiliation(s)
- Sangeeta Budhia
- Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES, United Kingdom
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20
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Audigé A, Schlaepfer E, Joller H, Speck RF. Uncoupled anti-HIV and immune-enhancing effects when combining IFN-alpha and IL-7. THE JOURNAL OF IMMUNOLOGY 2005; 175:3724-36. [PMID: 16148118 DOI: 10.4049/jimmunol.175.6.3724] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cytokine-based therapies have been examined for purging viral reservoirs and immunomodulation in HIV infection. However, single cytokines did not result in either HIV eradication or an efficient HIV-specific immune response. We hypothesize that cytokines with distinct biologic effects need to be combined for immunotherapy of HIV infection. In this study, we investigated the anti-HIV activity and immune-enhancing effects of the combination of IFN-alpha and IL-7. In human lymphocyte aggregate cultures infected ex vivo with the X4 HIV strain NL4-3, IFN-alpha/IL-7 potently inhibited HIV replication and preserved CD4(+) T cells, probably by up-regulating Bcl-2. IFN-alpha/IL-7 also strongly inhibited R5 HIV replication. Furthermore, in allogeneic MLRs, IFN-alpha/IL-7 increased T cell proliferation and IFN-gamma production. IFN-alpha alone also had strong anti-HIV activity, but neither preserved CD4(+) T cells nor increased T cell responses in MLRs. IL-7 alone maintained T cells and enhanced T cell activation in MLRs, but only moderately inhibited or increased HIV replication. Thus, coadministration of IFN-alpha/IL-7 combines the potent anti-HIV activity of IFN-alpha with the beneficial effects of IL-7 on T cell survival and function. We speculate that IFN-alpha will block viral replication, activate APCs, and up-regulate MHC molecules, thus allowing IL-7 to display its effects for generating an efficient immune response. In this scenario, the known reactivation of latent HIV by IL-7 may be advantageous.
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Affiliation(s)
- Annette Audigé
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, Zurich, Switzerland.
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Lee C, Tomkowicz B, Freedman BD, Collman RG. HIV-1 gp120-induced TNF-{alpha} production by primary human macrophages is mediated by phosphatidylinositol-3 (PI-3) kinase and mitogen-activated protein (MAP) kinase pathways. J Leukoc Biol 2005; 78:1016-23. [PMID: 16081599 DOI: 10.1189/jlb.0105056] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) infection is initiated by binding of the viral envelope glycoprotein gp120 to CD4 followed by a chemokine receptor, but these interactions may also take place independently from infection. gp120 stimulation of primary human macrophages is known to trigger production of cytokines implicated in pathogenesis, particularly tumor necrosis factor alpha (TNF-alpha), but the mechanisms have not been determined. We sought to define the pathways responsible for TNF-alpha secretion by monocyte-derived macrophages (MDM) following HIV-1 gp120 stimulation. MDM exposure to recombinant macrophage-tropic (R5) gp120 led to dose- and donor-dependent release of TNF-alpha, which was cyclohexamide-sensitive and associated with up-regulated message. Pretreatment with specific inhibitors of the mitogen-activated protein kinases (MAPK) extracellular signal-regulated kinase 1/2 (ERK-1/2; PD98059, U0126) and p38 (SB202190, PD169316) inhibited the secretion of TNF-alpha. gp120-elicited TNF-alpha production was also blocked by phosphatidylinositol-3 kinase (PI-3K) inhibitors (wortmannin, LY294002). Moreover, PI-3K inhibition ablated gp120-induced phosphorylation of p38 and ERK-1/2. The response was inhibited by a CC chemokine receptor 5 (CCR5)-specific antagonist, indicating that CCR5 was in large part responsible. These results indicate that gp120-elicited TNF-alpha production by macrophages involves chemokine receptor-mediated PI-3K and MAPK activation, that PI-3K is an upstream regulator of MAPK in this pathway, and that p38 and ERK-1/2 independently regulate TNF-alpha production. These gp120-triggered signaling pathways may be responsible for inappropriate production of proinflammatory cytokines by macrophages, which are believed to play a role in immunopathogenesis and in neurological sequelae of AIDS.
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Affiliation(s)
- Chuhee Lee
- Department of Medicine, University of Pennsylvania school of Medicine, Philadelphia, PA 19104, USA
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Schlaepfer E, Audigé A, von Beust B, Manolova V, Weber M, Joller H, Bachmann MF, Kundig TM, Speck RF. CpG oligodeoxynucleotides block human immunodeficiency virus type 1 replication in human lymphoid tissue infected ex vivo. J Virol 2004; 78:12344-54. [PMID: 15507621 PMCID: PMC525063 DOI: 10.1128/jvi.78.22.12344-12354.2004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Oligodeoxynucleotides (ODNs) with immunomodulatory motifs control a number of microbial infections in animal models, presumably by acting through toll-like receptor 9 (TLR9) to induce a number of cytokines (e.g., alpha interferon and tumor necrosis factor alpha). The immunomodulatory motif consists of unmethylated sequences of cytosine and guanosine (CpG motif). ODNs without CpG motifs do not trigger TLR9. We hypothesized that triggering of TLR9 generates a cellular environment unfavorable for human immunodeficiency virus (HIV) replication. We tested this hypothesis in human lymphocyte cultures and found that phosphorothioate-modified ODN CpG2006 (type B ODNs) inhibited HIV replication nearly completely and prevented the loss of CD4(+) T cells. ODNs CpG2216 and CpG10 (type A ODNs) were less effective. CpG2006 blocked HIV replication in purified CD4(+) T cells and T-cell lines; CpG10 was ineffective in this setting, indicating that type A ODNs may inhibit HIV replication in CD4(+) T-cell lines indirectly through a separate cell subset. However, control ODNs without CpG motifs also showed anti-HIV effects, indicating that these effects are nonspecific and not due to TLR9 triggering. The mechanism of action is not clear. CpG2006 and its control ODN blocked syncytium formation in a cell fusion-based assay, but CpG10, CpG2216, and their control ODNs did not. The latter types interfered with the HIV replication cycle during disassembly or reverse transcription. In contrast, CpG2006 and CpG2216 specifically induced cytokines critical to initiation of the innate immune response. In summary, the nonspecific anti-HIV activity of CpG ODNs, their ability to stimulate HIV replication in latently infected cells, potentially resulting in their elimination, and their documented ability to link the innate and adaptive immune responses make them attractive candidates for further study as anti-HIV drugs.
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Affiliation(s)
- Erika Schlaepfer
- Division of Infectious Diseases and Hospital Epidemiology, Department of Internal Medicine, University Hospital of Zurich, Raemistrasse 100, 8091 Zurich, Switzerland
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