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Zhao NQ, Pi R, Nguyen DN, Ranganath T, Seiler C, Holmes S, Marson A, Blish CA. NKp30 and NKG2D contribute to natural killer recognition of HIV-infected cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.24.600449. [PMID: 38979175 PMCID: PMC11230221 DOI: 10.1101/2024.06.24.600449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Natural killer (NK) cells respond rapidly in early HIV-1 infection. HIV-1 prevention and control strategies harnessing NK cells could be enabled by mechanistic understanding of how NK cells recognize HIV-infected T cells. Here, we profiled the phenotype of human primary NK cells responsive to autologous HIV-1-infected CD4 + T cells in vitro. We characterized the patterns of NK cell ligand expression on CD4 + T cells at baseline and after infection with a panel of transmitted/founder HIV-1 strains to identify key receptor-ligand pairings. CRISPR editing of CD4 + T cells to knockout the NKp30 ligand B7-H6, or the NKG2D ligands MICB or ULBP2 reduced NK cell responses to HIV-infected cells in some donors. In contrast, overexpression of NKp30 or NKG2D in NK cells enhanced their targeting of HIV-infected cells. Collectively, we identified receptor-ligand pairs including NKp30:B7-H6 and NKG2D:MICB/ULBP2 that contribute to NK cell recognition of HIV-infected cells.
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Fittje P, Hœlzemer A, Garcia-Beltran WF, Vollmers S, Niehrs A, Hagemann K, Martrus G, Körner C, Kirchhoff F, Sauter D, Altfeld M. HIV-1 Nef-mediated downregulation of CD155 results in viral restriction by KIR2DL5+ NK cells. PLoS Pathog 2022; 18:e1010572. [PMID: 35749424 PMCID: PMC9231786 DOI: 10.1371/journal.ppat.1010572] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 05/05/2022] [Indexed: 01/02/2023] Open
Abstract
Antiviral NK cell activity is regulated through the interaction of activating and inhibitory NK cell receptors with their ligands on infected cells. HLA class I molecules serve as ligands for most killer cell immunoglobulin-like receptors (KIRs), but no HLA class I ligands for the inhibitory NK cell receptor KIR2DL5 have been identified to date. Using a NK cell receptor/ligand screening approach, we observed no strong binding of KIR2DL5 to HLA class I or class II molecules, but confirmed that KIR2DL5 binds to the poliovirus receptor (PVR, CD155). Functional studies using primary human NK cells revealed a significantly decreased degranulation of KIR2DL5+ NK cells in response to CD155-expressing target cells. We subsequently investigated the role of KIR2DL5/CD155 interactions in HIV-1 infection, and showed that multiple HIV-1 strains significantly decreased CD155 expression levels on HIV-1-infected primary human CD4+ T cells via a Nef-dependent mechanism. Co-culture of NK cells with HIV-1-infected CD4+ T cells revealed enhanced anti-viral activity of KIR2DL5+ NK cells against wild-type versus Nef-deficient viruses, indicating that HIV-1-mediated downregulation of CD155 renders infected cells more susceptible to recognition by KIR2DL5+ NK cells. These data show that CD155 suppresses the antiviral activity of KIR2DL5+ NK cells and is downmodulated by HIV-1 Nef protein as potential trade-off counteracting activating NK cell ligands, demonstrating the ability of NK cells to counteract immune escape mechanisms employed by HIV-1. HIV infection remains a global health emergency that has caused around 36 million deaths. NK cells play an important role in the control of HIV-1 infections, and are able to detect and destroy infected cells using a large array of activating and inhibitory receptors, including KIRs. Here we demonstrate that CD155 serves as a functional interaction partner for the inhibitory NK cell receptor KIR2DL5, and that KIR2DL5+ NK cells are inhibited by CD155-expressing target cells. CD155 surface expression on HIV-1-infected CD4+ T cells was downregulated by the HIV-1 Nef protein, resulting in increased anti-viral activity of KIR2DL5+ NK cells through the loss of inhibitory signals. Taken together, these studies demonstrate functional consequences of the novel interaction between KIR2DL5 and CD155 for the antiviral activity of KIR2DL5+ NK cells during HIV-1 infection.
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Affiliation(s)
- Pia Fittje
- Leibniz Institute of Virology (LIV), Hamburg, Germany
| | - Angelique Hœlzemer
- Leibniz Institute of Virology (LIV), Hamburg, Germany
- First Department of Internal Medicine, Division of Infectious Diseases, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Wilfredo F. Garcia-Beltran
- Leibniz Institute of Virology (LIV), Hamburg, Germany
- Department of Pathology, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, United States of America
| | | | - Annika Niehrs
- Leibniz Institute of Virology (LIV), Hamburg, Germany
| | | | | | | | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Daniel Sauter
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Marcus Altfeld
- Leibniz Institute of Virology (LIV), Hamburg, Germany
- German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
- * E-mail:
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3
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Patient-Derived HIV-1 Nef Alleles Reveal Uncoupling of CD4 Downregulation and SERINC5 Antagonism Functions of the Viral Pathogenesis Factor. J Acquir Immune Defic Syndr 2021; 85:e23-e26. [PMID: 32541384 DOI: 10.1097/qai.0000000000002418] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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4
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Kaw S, Ananth S, Tsopoulidis N, Morath K, Coban BM, Hohenberger R, Bulut OC, Klein F, Stolp B, Fackler OT. HIV-1 infection of CD4 T cells impairs antigen-specific B cell function. EMBO J 2020; 39:e105594. [PMID: 33146906 PMCID: PMC7737609 DOI: 10.15252/embj.2020105594] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 09/28/2020] [Accepted: 10/01/2020] [Indexed: 12/12/2022] Open
Abstract
Failures to produce neutralizing antibodies upon HIV‐1 infection result in part from B‐cell dysfunction due to unspecific B‐cell activation. How HIV‐1 affects antigen‐specific B‐cell functions remains elusive. Using an adoptive transfer mouse model and ex vivo HIV infection of human tonsil tissue, we found that expression of the HIV‐1 pathogenesis factor NEF in CD4 T cells undermines their helper function and impairs cognate B‐cell functions including mounting of efficient specific IgG responses. NEF interfered with T cell help via a specific protein interaction motif that prevents polarized cytokine secretion at the T‐cell–B‐cell immune synapse. This interference reduced B‐cell activation and proliferation and thus disrupted germinal center formation and affinity maturation. These results identify NEF as a key component for HIV‐mediated dysfunction of antigen‐specific B cells. Therapeutic targeting of the identified molecular surface in NEF will facilitate host control of HIV infection.
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Affiliation(s)
- Sheetal Kaw
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Swetha Ananth
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany.,German Centre for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - Nikolaos Tsopoulidis
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Katharina Morath
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Bahar M Coban
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany.,German Centre for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - Ralph Hohenberger
- Department of Otorhinolaryngology, University Hospital Heidelberg, Heidelberg, Germany
| | - Olcay C Bulut
- German Centre for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany.,Department of Otorhinolaryngology, Head and Neck Surgery, SLK Klinikum Am Gesundbrunnen, Heilbronn, Germany
| | - Florian Klein
- Laboratory of Experimental Immunology, Institute of Virology, University Hospital of Cologne, Cologne, Germany.,German Centre for Infection Research (DZIF), Partner Site Köln, Köln, Germany
| | - Bettina Stolp
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Oliver T Fackler
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany.,German Centre for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
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5
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Vizcarra P, Gallego J, Vivancos MJ, Sifuentes WA, Llop M, Casado JL. Evaluation of the fracture risk assessment tool for determining bone disease and the impact of secondary causes of osteoporosis in people living with HIV. HIV Res Clin Pract 2020; 21:63-71. [PMID: 32698706 DOI: 10.1080/25787489.2020.1794438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND Among HIV-infected individuals, screening for bone disease is encouraged to assess reversible risk factors and plan therapeutic interventions. OBJECTIVE We assessed the usefulness of Fracture Risk Assessment (FRAX) tool to identify candidates for dual X-ray absorptiometry (DXA) scan, or individuals with bone loss progression. We further explored how secondary causes of osteoporosis are reflected on FRAX. METHODS Longitudinal study of 217 consecutive individuals (mean, 45.8 years, 24% females) included after DXA scan. FRAX was calculated without/with femoral neck bone mineral density (BMD), checking the box of "secondary osteoporosis" for all the individuals. RESULTS Low BMD was observed in 133/217 (61%) individuals, of whom 98.5% had not been selected as candidates for DXA by current FRAX thresholds. Specifically, 23% of individuals aged <50 had low BMD but none was candidate for DXA. Adding BMD data, FRAX results increased by 50-100%, with 2/217 individuals (1%) above the thresholds. Classical and HIV-related secondary causes of osteoporosis (observed in 98% overall) correlated with low BMD, modifying significantly FRAX results (HCV coinfection, +124%; longer time of HIV infection, +93%; longer time on antiretroviral therapy, +147%; tenofovir exposure +36%). Individuals with lower BMD and higher FRAX results at inclusion had less bone decline in a follow-up DXA after a median of 3.5 years. CONCLUSIONS Currently recommended FRAX thresholds are not useful to select candidates for DXA scan, which could delay its performance in a population with a high prevalence of secondary factors for low BMD. Classical and HIV-related factors alter BMD and fracture risk estimation.
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Affiliation(s)
- Pilar Vizcarra
- Department of Infectious Diseases, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
| | - Juan Gallego
- Department of Infectious Diseases, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
| | - María J Vivancos
- Department of Infectious Diseases, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
| | - Walter A Sifuentes
- Department of Rheumatology, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
| | - María Llop
- Department of Rheumatology, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
| | - José L Casado
- Department of Infectious Diseases, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
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Umviligihozo G, Cobarrubias KD, Chandrarathna S, Jin SW, Reddy N, Byakwaga H, Muzoora C, Bwana MB, Lee GQ, Hunt PW, Martin JN, Brumme CJ, Bangsberg DR, Karita E, Allen S, Hunter E, Ndung'u T, Brumme ZL, Brockman MA. Differential Vpu-Mediated CD4 and Tetherin Downregulation Functions among Major HIV-1 Group M Subtypes. J Virol 2020; 94:e00293-20. [PMID: 32376625 PMCID: PMC7343213 DOI: 10.1128/jvi.00293-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 04/30/2020] [Indexed: 12/12/2022] Open
Abstract
Downregulation of BST-2/tetherin and CD4 by HIV-1 viral protein U (Vpu) promotes viral egress and allows infected cells to evade host immunity. Little is known however about the natural variability in these Vpu functions among the genetically diverse viral subtypes that contribute to the HIV-1 pandemic. We collected Vpu isolates from 332 treatment-naive individuals living with chronic HIV-1 infection in Uganda, Rwanda, South Africa, and Canada. Together, these Vpu isolates represent four major HIV-1 group M subtypes (A [n = 63], B [n = 84], C [n = 94], and D [n = 59]) plus intersubtype recombinants and uncommon strains (n = 32). The ability of each Vpu clone to downregulate endogenous CD4 and tetherin was quantified using flow cytometry following transfection into an immortalized T-cell line and compared to that of a reference Vpu clone derived from HIV-1 subtype B NL4.3. Overall, the median CD4 downregulation function of natural Vpu isolates was similar to that of NL4.3 (1.01 [interquartile range {IQR}, 0.86 to 1.18]), while the median tetherin downregulation function was moderately lower than that of NL4.3 (0.90 [0.79 to 0.97]). Both Vpu functions varied significantly among HIV-1 subtypes (Kruskal-Wallis P < 0.0001). Specifically, subtype C clones exhibited the lowest CD4 and tetherin downregulation activities, while subtype D and B clones were most functional for both activities. We also identified Vpu polymorphisms associated with CD4 or tetherin downregulation function and validated six of these using site-directed mutagenesis. Our results highlight the marked extent to which Vpu function varies among global HIV-1 strains, raising the possibility that natural variation in this accessory protein may contribute to viral pathogenesis and/or spread.IMPORTANCE The HIV-1 accessory protein Vpu enhances viral spread by downregulating CD4 and BST-2/tetherin on the surface of infected cells. Natural variability in these Vpu functions may contribute to HIV-1 pathogenesis, but this has not been investigated among the diverse viral subtypes that contribute to the HIV-1 pandemic. In this study, we found that Vpu function differs significantly among HIV-1 subtypes A, B, C, and D. On average, subtype C clones displayed the lowest ability to downregulate both CD4 and tetherin, while subtype B and D clones were more functional. We also identified Vpu polymorphisms that associate with functional differences among HIV-1 isolates and subtypes. Our study suggests that genetic diversity in Vpu may play an important role in the differential pathogenesis and/or spread of HIV-1.
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Affiliation(s)
- Gisele Umviligihozo
- Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada
| | - Kyle D Cobarrubias
- Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada
| | - Sandali Chandrarathna
- Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada
| | - Steven W Jin
- Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada
| | - Nicole Reddy
- University of KwaZulu-Natal, Durban, South Africa
- Africa Health Research Institute, Durban, South Africa
| | - Helen Byakwaga
- Mbarara University of Science and Technology, Mbarara, Uganda
- University of California, San Francisco, California, USA
| | - Conrad Muzoora
- Mbarara University of Science and Technology, Mbarara, Uganda
| | - Mwebesa B Bwana
- Mbarara University of Science and Technology, Mbarara, Uganda
| | - Guinevere Q Lee
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada
| | - Peter W Hunt
- University of California, San Francisco, California, USA
| | - Jeff N Martin
- University of California, San Francisco, California, USA
| | - Chanson J Brumme
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada
- University of British Columbia, Vancouver, British Columbia, Canada
| | - David R Bangsberg
- Oregon Health and Science University-Portland State University School of Public Health, Portland, Oregon, USA
| | - Etienne Karita
- Rwanda Zambia HIV Research Group-Projet San Francisco, Kigali, Rwanda
| | - Susan Allen
- Rwanda Zambia HIV Research Group-Projet San Francisco, Kigali, Rwanda
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia, USA
- Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
| | - Eric Hunter
- Rwanda Zambia HIV Research Group-Projet San Francisco, Kigali, Rwanda
- Emory Vaccine Center at Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, USA
| | - Thumbi Ndung'u
- University of KwaZulu-Natal, Durban, South Africa
- Africa Health Research Institute, Durban, South Africa
- Max Planck Institute for Infection Biology, Berlin, Germany
- Division of Infection and Immunity, University College London, London, United Kingdom
| | - Zabrina L Brumme
- Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada
| | - Mark A Brockman
- Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada
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7
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Abstract
The continuous interactions between host and pathogens during their coevolution have shaped both the immune system and the countermeasures used by pathogens. Natural killer (NK) cells are innate lymphocytes that are considered central players in the antiviral response. Not only do they express a variety of inhibitory and activating receptors to discriminate and eliminate target cells but they can also produce immunoregulatory cytokines to alert the immune system. Reciprocally, several unrelated viruses including cytomegalovirus, human immunodeficiency virus, influenza virus, and dengue virus have evolved a multitude of mechanisms to evade NK cell function, such as the targeting of pathways for NK cell receptors and their ligands, apoptosis, and cytokine-mediated signaling. The studies discussed in this article provide further insights into the antiviral function of NK cells and the pathways involved, their constituent proteins, and ways in which they could be manipulated for host benefit.
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Affiliation(s)
- Mathieu Mancini
- Department of Human Genetics, McGill University, Montreal, Quebec H3A 0C7, Canada;,
- McGill University Research Centre on Complex Traits, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Silvia M. Vidal
- Department of Human Genetics, McGill University, Montreal, Quebec H3A 0C7, Canada;,
- McGill University Research Centre on Complex Traits, McGill University, Montreal, Quebec H3G 0B1, Canada
- Department of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
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8
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Multifunctional Roles of the N-Terminal Region of HIV-1 SF2Nef Are Mediated by Three Independent Protein Interaction Sites. J Virol 2019; 94:JVI.01398-19. [PMID: 31597760 DOI: 10.1128/jvi.01398-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 10/01/2019] [Indexed: 01/23/2023] Open
Abstract
HIV-1 Nef promotes virus spread and disease progression by altering host cell transport and signaling processes through interaction with multiple host cell proteins. The N-terminal region in HIV-1 Nef encompassing residues 12 to 39 has been implicated in many Nef activities, including disruption of CD4 T lymphocyte polarization and homing to lymph nodes, antagonism of SERINC5 restriction to virion infectivity, downregulation of cell surface CD4 and major histocompatibility complex class I (MHC-I), release of Nef-containing extracellular vesicles, and phosphorylation of Nef by recruitment of the Nef-associated kinase complex (NAKC). How this region mediates these pleiotropic functions is unclear. Characterization of a panel of alanine mutants spanning the N-terminal region to identify specific functional determinants revealed this region to be dispensable for effects of Nef from HIV-1 strain SF2 (HIV-1SF2Nef) on T cell actin organization and chemotaxis, retargeting of the host cell kinase Lck to the trans-Golgi network, and incorporation of Nef into extracellular vesicles. MHC-I downmodulation was specific to residue M20, and inhibition of T cell polarization by Nef required the integrity of the entire region. In contrast, downmodulation of cell surface CD4 and SERINC5 antagonism were mediated by a specific motif encompassing residues 32 to 39 that was also essential for efficient HIV replication in primary CD4 T lymphocytes. Finally, Nef phosphorylation via association with the NAKC was mediated by two EP repeats within residues 24 to 29 but was dispensable for other functions. These results identify the N-terminal region as a multifunctional interaction module for at least three different host cell ligands that mediate independent functions of HIV-1SF2Nef to facilitate immune evasion and virus spread.IMPORTANCE HIV-1 Nef critically determines virus spread and disease progression in infected individuals by acting as a protein interaction adaptor via incompletely defined mechanisms and ligands. Residues 12 to 39 near the N terminus of Nef have been described as an interaction platform for the Nef-associated kinase complex (NAKC) and were recently identified as essential determinants for a broad range of Nef activities. Here, we report a systematic mapping of this amino acid stretch that revealed the presence of three independent interaction motifs with specific ligands and activities. While downmodulation of cell surface MHC-I depends on M20, two EP repeats are the minimal binding site for the NAKC, and residues 32 to 39 mediate antagonism of the host cell restriction factor SERINC5 as well as downmodulation of cell surface CD4. These results reveal that the N-terminal region of HIV-1SF2Nef is a versatile and multifunctional protein interaction module that exerts essential functions of the pathogenicity factor via independent mechanisms.
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9
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Potential of the NKG2D/NKG2DL Axis in NK Cell-Mediated Clearance of the HIV-1 Reservoir. Int J Mol Sci 2019; 20:ijms20184490. [PMID: 31514330 PMCID: PMC6770208 DOI: 10.3390/ijms20184490] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 09/02/2019] [Accepted: 09/09/2019] [Indexed: 12/21/2022] Open
Abstract
Viral persistency in latently infected CD4+ T cells despite antiretroviral therapy (ART) represents a major drawback in the fight against HIV-1. Efforts to purge latent HIV-1 have been attempted using latency reversing agents (LRAs) that activate expression of the quiescent virus. However, initial trials have shown that immune responses of ART-treated patients are ineffective at clearing LRA-reactivated HIV-1 reservoirs, suggesting that an adjuvant immunotherapy is needed. Here we overview multiple lines of evidence indicating that natural killer (NK) cells have the potential to induce anti-HIV-1 responses relevant for virus eradication. In particular, we focus on the role of the NKG2D activating receptor that crucially enables NK cell-mediated killing of HIV-1-infected cells. We describe recent data indicating that LRAs can synergize with HIV-1 at upregulating ligands for NKG2D (NKG2DLs), hence sensitizing T cells that exit from viral latency for recognition and lysis by NK cells; in addition, we report in vivo and ex vivo data showing the potential benefits and drawbacks that LRAs may have on NKG2D expression and, more in general, on the cytotoxicity of NK cells. Finally, we discuss how the NKG2D/NKG2DLs axis can be exploited for the development of effective HIV-1 eradication strategies combining LRA-induced virus reactivation with recently optimized NK cell-based immunotherapies.
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10
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Potential impact of the antirheumatic agent auranofin on proviral HIV-1 DNA in individuals under intensified antiretroviral therapy: Results from a randomised clinical trial. Int J Antimicrob Agents 2019; 54:592-600. [PMID: 31394172 DOI: 10.1016/j.ijantimicag.2019.08.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 07/17/2019] [Accepted: 08/01/2019] [Indexed: 11/24/2022]
Abstract
Antiretroviral therapy (ART) is typically composed of a combination of three antiretroviral drugs and is the treatment of choice for people with human immunodeficiency virus type 1/acquired immune deficiency syndrome (HIV-1/AIDS). However, it is unable to impact on viral reservoirs, which harbour latent HIV-1 genomes that are able to reignite the infection upon treatment suspension. The aim of this study was to provide an estimate of the safety of the disease-modifying antirheumatic agent auranofin and its impact on the HIV-1 reservoir in humans under intensified ART. For this purpose, an interim analysis was conducted of three of the six arms of the NCT02961829 clinical trial (five patients each) with: no intervention, i.e. continuation of first-line ART; intensified ART (ART + dolutegravir and maraviroc); and intensified ART plus auranofin. Auranofin treatment was found to be well tolerated. No major adverse events were detected apart from a transient decrease in CD4+ T-cell counts at Weeks 8 and 12. Auranofin decreased total viral DNA in peripheral blood mononuclear cells compared with ART-only regimens at Week 20 (P = 0.036) and induced a decrease in integrated viral DNA as quantified by Alu PCR. Despite the limited number of patient-derived sequences available in this study, phylogenetic analyses of nef sequences support the idea that auranofin may impact on the viral reservoir. [ClinicalTrials.gov ID: NCT02961829].
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11
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DNAM-1 Activating Receptor and Its Ligands: How Do Viruses Affect the NK Cell-Mediated Immune Surveillance during the Various Phases of Infection? Int J Mol Sci 2019; 20:ijms20153715. [PMID: 31366013 PMCID: PMC6695959 DOI: 10.3390/ijms20153715] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 07/24/2019] [Accepted: 07/27/2019] [Indexed: 02/06/2023] Open
Abstract
Natural Killer (NK) cells play a critical role in host defense against viral infections. The mechanisms of recognition and killing of virus-infected cells mediated by NK cells are still only partially defined. Several viruses induce, on the surface of target cells, the expression of molecules that are specifically recognized by NK cell-activating receptors. The main NK cell-activating receptors involved in the recognition and killing of virus-infected cells are NKG2D and DNAM-1. In particular, ligands for DNAM-1 are nectin/nectin-like molecules involved also in mechanisms allowing viral infection. Viruses adopt several immune evasion strategies, including those affecting NK cell-mediated immune surveillance, causing persistent viral infection and the development of virus-associated diseases. The virus's immune evasion efficacy depends on molecules differently expressed during the various phases of infection. In this review, we overview the molecular strategies adopted by viruses, specifically cytomegalovirus (CMV), human immunodeficiency virus (HIV-1), herpes virus (HSV), Epstein-Barr virus (EBV) and hepatitis C virus (HCV), aiming to evade NK cell-mediated surveillance, with a special focus on the modulation of DNAM-1 activating receptor and its ligands in various phases of the viral life cycle. The increasing understanding of mechanisms involved in the modulation of activating ligands, together with those mediating the viral immune evasion strategies, would provide critical tools leading to design novel NK cell-based immunotherapies aiming at viral infection control, thus improving cure strategies of virus-associated diseases.
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12
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Abstract
Latent viral reservoirs in long-living cell populations are the main obstacle to a cure of HIV/AIDS. HIV-1 latency is controlled by the activation status of infected cells and their ability to return to a resting phenotype associated with silencing of viral gene expression. These cellular features are not just determined by the host since HIV-1 has evolved sophisticated mechanisms to alter cellular activation and survival to its advantage. Especially the HIV-1 accessory proteins Nef and Vpu exert numerous activities to promote viral replication and immune evasion affecting the size and preservation of the viral reservoir. Here, we review how antagonistic and synergistic functions of Nef and Vpu might affect HIV-1 latency. We also discuss whether these two accessory factors represent suitable targets to improve the ‘shock and kill’ cure strategy.
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Affiliation(s)
- Dorota Kmiec
- Institute of Molecular Virology, ULM University Medical Center, Meyerhofstr 1, Ulm 89081, Germany
| | - Smitha Srinivasachar
- Institute of Molecular Virology, ULM University Medical Center, Meyerhofstr 1, Ulm 89081, Germany
| | - Frank Kirchhoff
- Institute of Molecular Virology, ULM University Medical Center, Meyerhofstr 1, Ulm 89081, Germany
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13
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Huerga H, Ferlazzo G, Wanjala S, Bastard M, Bevilacqua P, Ardizzoni E, Sitienei J, Bonnet M. Mortality in the first six months among HIV-positive and HIV-negative patients empirically treated for tuberculosis. BMC Infect Dis 2019; 19:132. [PMID: 30744603 PMCID: PMC6369550 DOI: 10.1186/s12879-019-3775-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 02/04/2019] [Indexed: 01/20/2023] Open
Abstract
Background Empirical treatment of tuberculosis (TB) may be necessary in patients with negative or no Xpert MTB/RIF results. In a context with access to Xpert, we assessed mortality in the 6 months after the initial TB consultation among HIV-positive and HIV-negative patients who received empirical TB treatment or TB treatment based on bacteriological confirmation and we compared it with the mortality among those who did not receive TB treatment. Methods This prospective cohort study included consecutively adult patients with signs and symptoms of TB attending an outpatient TB clinic in Western Kenya. At the first consultation, patients received a clinical exam and chest X-ray. Sputum was collected for microscopy, Xpert and Mycobacterium tuberculosis complex (MTB) culture. Patients not started on TB treatment were reassessed after 5 days. All patients bacteriologically confirmed (positive Xpert or culture) received TB treatment. Empirical treatment was defined as a decision to start TB treatment without bacteriological confirmation. Patients were reassessed after 6 months. Results Of 606 patients included, 344/606 (56.8%) were women. Median age was 35 years [Interquartile Range (IQR):27–47] and 398/594 (67.0%) were HIV-positive. In total, 196/606 (32.3%) patients were Xpert- or culture-positive and 331/606 (54.6%) started TB treatment. Overall, 100/398 (25.1%) HIV-positive and 31/196 (15.8%) HIV-negative patients received empirical treatment. Mortality in the 6 months following the first consultation was 1.6 and 0.8/100 patient-months among HIV-positive and HIV-negative patients respectively. In the multivariate analyses, TB treatment - whether empirical or based on bacteriological confirmation- was not associated with increased mortality among HIV-positive patients (aHR:2.51, 95%CI:0.79–7.90 and aHR:1.25, 95%CI:0.37–4.21 respectively). However, HIV-negative patients who received empirical treatment had a higher risk of mortality (aHR:4.85, 95%CI:1.08–21.67) compared to those not started on treatment. HIV-negative patients treated for TB based on bacteriological confirmation did not have a different risk of mortality (aHR:0.77, 95%CI:0.08–7.41). Conclusions Our findings suggest that in a context with access to Xpert, clinicians should continue using empirical TB treatment in HIV-positive patients with signs and symptoms of TB and negative Xpert results. However, differential diagnoses other than TB should be actively sought before initiating empirical TB treatment, particularly in HIV-negative patients.
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Affiliation(s)
| | | | | | | | | | - Elisa Ardizzoni
- Médecins Sans Frontières, Paris, France.,Institute of Tropical Medicine, Antwerp, Belgium
| | | | - Maryline Bonnet
- Epicentre, Paris, France.,IRD UMI 233 TransVIHMI - UM - INSERM U1175, Montpellier, France
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14
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Langer S, Hammer C, Hopfensperger K, Klein L, Hotter D, De Jesus PD, Herbert KM, Pache L, Smith N, van der Merwe JA, Chanda SK, Fellay J, Kirchhoff F, Sauter D. HIV-1 Vpu is a potent transcriptional suppressor of NF-κB-elicited antiviral immune responses. eLife 2019; 8:41930. [PMID: 30717826 PMCID: PMC6372280 DOI: 10.7554/elife.41930] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 01/26/2019] [Indexed: 12/11/2022] Open
Abstract
Many viral pathogens target innate sensing cascades and/or cellular transcription factors to suppress antiviral immune responses. Here, we show that the accessory viral protein U (Vpu) of HIV-1 exerts broad immunosuppressive effects by inhibiting activation of the transcription factor NF-κB. Global transcriptional profiling of infected CD4 +T cells revealed that vpu-deficient HIV-1 strains induce substantially stronger immune responses than the respective wild type viruses. Gene set enrichment analyses and cytokine arrays showed that Vpu suppresses the expression of NF-κB targets including interferons and restriction factors. Mutational analyses demonstrated that this immunosuppressive activity of Vpu is independent of its ability to counteract the restriction factor and innate sensor tetherin. However, Vpu-mediated inhibition of immune activation required an arginine residue in the cytoplasmic domain that is critical for blocking NF-κB signaling downstream of tetherin. In summary, our findings demonstrate that HIV-1 Vpu potently suppresses NF-κB-elicited antiviral immune responses at the transcriptional level. The Human Immunodeficiency Virus (or HIV for short) has infected more than 70 million people worldwide. Although effective therapies exist to prevent the replication of the virus and the development to AIDS, there is no cure or vaccine, and the virus still spreads efficiently in human populations, infecting about 1.8 million new people every year. The unfortunate success of HIV can in part be explained by several viral proteins that trick our immune system and enable the virus to persist at high levels in the human body. For example, an HIV protein called viral protein U (Vpu) prevents infected cells from producing alarm signals such as interferons, which usually help healthy, uninfected cells to defend themselves against viruses. However, the extent to which Vpu interferes with interferons and other proteins involved in immune responses has remained unclear. To address this question, Langer, Hammer, Hopfensperger et al. compared how different variants of HIV affect immune responses in human cells. The experiments showed that cells infected with HIV variants lacking Vpu released larger amounts of interferons and other cellular proteins that are involved in immune responses compared to HIV variants with Vpu. Further experiments showed that Vpu works by inhibiting the activation of a protein called NF-κB, which usually switches on genes that encode interferons and many other proteins involved in immune responses. These findings demonstrate that Vpu has a broader impact on the human immune response than previously thought. In order to multiply efficiently, HIV initially requires the NF-κB protein to be active. Therefore, when NF-κB is inactive, HIV may adopt a dormant state that prevents current antiviral drug treatments from eradicating the virus in the human body. In the future, developing new drugs that can activate dormant HIV particles may therefore have the potential to help cure HIV infections.
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Affiliation(s)
- Simon Langer
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany.,Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, United States
| | - Christian Hammer
- School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | | | - Lukas Klein
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Dominik Hotter
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Paul D De Jesus
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, United States
| | - Kristina M Herbert
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, United States
| | - Lars Pache
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, United States
| | - Nikaïa Smith
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | | | - Sumit K Chanda
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, United States
| | - Jacques Fellay
- School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
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15
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Lamas-Murua M, Stolp B, Kaw S, Thoma J, Tsopoulidis N, Trautz B, Ambiel I, Reif T, Arora S, Imle A, Tibroni N, Wu J, Cui G, Stein JV, Tanaka M, Lyck R, Fackler OT. HIV-1 Nef Disrupts CD4 + T Lymphocyte Polarity, Extravasation, and Homing to Lymph Nodes via Its Nef-Associated Kinase Complex Interface. THE JOURNAL OF IMMUNOLOGY 2018; 201:2731-2743. [PMID: 30257886 DOI: 10.4049/jimmunol.1701420] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 08/21/2018] [Indexed: 12/31/2022]
Abstract
HIV-1 Nef is a multifunctional protein that optimizes virus spread and promotes immune evasion of infected cells to accelerate disease progression in AIDS patients. As one of its activities, Nef reduces the motility of infected CD4+ T lymphocytes in confined space. In vivo, Nef restricts T lymphocyte homing to lymph nodes as it reduces the ability for extravasation at the diapedesis step. Effects of Nef on T lymphocyte motility are typically mediated by its ability to reduce actin remodeling. However, interference with diapedesis does not depend on residues in Nef required for inhibition of host cell actin dynamics. In search for an alternative mechanism by which Nef could alter T lymphocyte extravasation, we noted that the viral protein interferes with the polarization of primary human CD4+ T lymphocytes upon infection with HIV-1. Expression of Nef alone is sufficient to disrupt T cell polarization, and this effect is conserved among lentiviral Nef proteins. Nef acts by arresting the oscillation of CD4+ T cells between polarized and nonpolarized morphologies. Mapping studies identified the binding site for the Nef-associated kinase complex (NAKC) as critical determinant of this Nef activity and a NAKC-binding-deficient Nef variant fails to impair CD4+ T lymphocyte extravasation and homing to lymph nodes. These results thus imply the disruption of T lymphocyte polarity via its NAKC binding site as a novel mechanism by which lentiviral Nef proteins alter T lymphocyte migration in vivo.
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Affiliation(s)
- Miguel Lamas-Murua
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Bettina Stolp
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Sheetal Kaw
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Judith Thoma
- Physical Chemistry of Biosystems, University of Heidelberg, 69120 Heidelberg, Germany
| | - Nikolaos Tsopoulidis
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Birthe Trautz
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Ina Ambiel
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Tatjana Reif
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Sakshi Arora
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Andrea Imle
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Nadine Tibroni
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Jingxia Wu
- T Cell Metabolism (D140), German Cancer Research Centre, 69120 Heidelberg, Germany
| | - Guoliang Cui
- T Cell Metabolism (D140), German Cancer Research Centre, 69120 Heidelberg, Germany
| | - Jens V Stein
- Theodor Kocher Institute, University of Bern, 3012 Bern, Switzerland; and
| | - Motomu Tanaka
- Physical Chemistry of Biosystems, University of Heidelberg, 69120 Heidelberg, Germany.,Center for Integrative Medicine and Physics, Institute for Advanced Study, Kyoto University, Kyoto 606-8501, Japan
| | - Ruth Lyck
- Theodor Kocher Institute, University of Bern, 3012 Bern, Switzerland; and
| | - Oliver T Fackler
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany;
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16
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Chase AJ, Wombacher R, Fackler OT. Intrinsic properties and plasma membrane trafficking route of Src family kinase SH4 domains sensitive to retargeting by HIV-1 Nef. J Biol Chem 2018; 293:7824-7840. [PMID: 29588370 DOI: 10.1074/jbc.ra118.002794] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Indexed: 01/18/2023] Open
Abstract
The HIV type 1 pathogenicity factor Nef enhances viral replication by modulating multiple host cell pathways, including tuning the activation state of infected CD4 T lymphocytes to optimize virus spread. For this, Nef inhibits anterograde transport of the Src family kinase (SFK) Lck toward the plasma membrane (PM). This leads to retargeting of the kinase to the trans-Golgi network, whereas the intracellular transport of a related SFK, Fyn, is unaffected by Nef. The 18-amino acid Src homology 4 (SH4) domain membrane anchor of Lck is necessary and sufficient for Nef-mediated retargeting, but other details of this process are not known. The goal of this study was therefore to identify characteristics of SH4 domains responsive to Nef and the transport machinery used. Screening a panel of SFK SH4 domains revealed two groups that were sensitive or insensitive for trans-Golgi network retargeting by Nef as well as the importance of the amino acid at position 8 for determining Nef sensitivity. Anterograde transport of Nef-sensitive domains was characterized by slower delivery to the PM and initial targeting to Golgi membranes, where transport was arrested in the presence of Nef. For Nef-sensitive SH4 domains, ectopic expression of the lipoprotein binding chaperone Unc119a or the GTPase Arl3 or reduction of their endogenous expression phenocopied the effect of Nef. Together, these results suggest that, analogous to K-Ras, Nef-sensitive SH4 domains are transported to the PM by a cycle of solubilization and membrane insertion and that intrinsic properties define SH4 domains as cargo of this Nef-sensitive lipoprotein binding chaperone-GTPase transport cycle.
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Affiliation(s)
- Amanda J Chase
- From the Department of Infectious Diseases, Center for Integrative Infectious Disease Research (CIID), Integrative Virology, University Hospital Heidelberg, Im Neuenheimer Feld 344, 69120 Heidelberg, Germany
| | - Rebecka Wombacher
- From the Department of Infectious Diseases, Center for Integrative Infectious Disease Research (CIID), Integrative Virology, University Hospital Heidelberg, Im Neuenheimer Feld 344, 69120 Heidelberg, Germany
| | - Oliver T Fackler
- From the Department of Infectious Diseases, Center for Integrative Infectious Disease Research (CIID), Integrative Virology, University Hospital Heidelberg, Im Neuenheimer Feld 344, 69120 Heidelberg, Germany
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17
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HLA Class I Downregulation by HIV-1 Variants from Subtype C Transmission Pairs. J Virol 2018; 92:JVI.01633-17. [PMID: 29321314 DOI: 10.1128/jvi.01633-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 12/23/2017] [Indexed: 02/08/2023] Open
Abstract
HIV-1 downregulates human leukocyte antigen A (HLA-A) and HLA-B from the surface of infected cells primarily to evade CD8 T cell recognition. HLA-C was thought to remain on the cell surface and bind inhibitory killer immunoglobulin-like receptors, preventing natural killer (NK) cell-mediated suppression. However, a recent study found HIV-1 primary viruses have the capacity to downregulate HLA-C. The goal of this study was to assess the heterogeneity of HLA-A, HLA-B, and HLA-C downregulation among full-length primary viruses from six chronically infected and six newly infected individuals from transmission pairs and to determine whether transmitted/founder variants exhibit common HLA class I downregulation characteristics. We measured HLA-A, HLA-B, HLA-C, and total HLA class I downregulation by flow cytometry of primary CD4 T cells infected with 40 infectious molecular clones. Primary viruses mediated a range of HLA class I downregulation capacities (1.3- to 6.1-fold) which could differ significantly between transmission pairs. Downregulation of HLA-C surface expression on infected cells correlated with susceptibility to in vitro NK cell suppression of virus release. Despite this, transmitted/founder variants did not share a downregulation signature and instead were more similar to the quasispecies of matched donor partners. These data indicate that a range of viral abilities to downregulate HLA-A, HLA-B, and HLA-C exist within and between individuals that can have functional consequences on immune recognition.IMPORTANCE Subtype C HIV-1 is the predominant subtype involved in heterosexual transmission in sub-Saharan Africa. Authentic subtype C viruses that contain natural sequence variations throughout the genome often are not used in experimental systems due to technical constraints and sample availability. In this study, authentic full-length subtype C viruses, including transmitted/founder viruses, were examined for the ability to disrupt surface expression of HLA class I molecules, which are central to both adaptive and innate immune responses to viral infections. We found that the HLA class I downregulation capacity of primary viruses varied, and HLA-C downregulation capacity impacted viral suppression by natural killer cells. Transmitted viruses were not distinct in the capacity for HLA class I downregulation or natural killer cell evasion. These results enrich our understanding of the phenotypic variation existing among natural HIV-1 viruses and how that might impact the ability of the immune system to recognize infected cells in acute and chronic infection.
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18
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Reeves DB, Peterson CW, Kiem HP, Schiffer JT. Autologous Stem Cell Transplantation Disrupts Adaptive Immune Responses during Rebound Simian/Human Immunodeficiency Virus Viremia. J Virol 2017; 91:e00095-17. [PMID: 28404854 PMCID: PMC5469274 DOI: 10.1128/jvi.00095-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 04/06/2017] [Indexed: 02/07/2023] Open
Abstract
Primary HIV-1 infection induces a virus-specific adaptive/cytolytic immune response that impacts the plasma viral load set point and the rate of progression to AIDS. Combination antiretroviral therapy (cART) suppresses plasma viremia to undetectable levels that rebound upon cART treatment interruption. Following cART withdrawal, the memory component of the virus-specific adaptive immune response may improve viral control compared to primary infection. Here, using primary infection and treatment interruption data from macaques infected with simian/human immunodeficiency virus (SHIV), we observe a lower peak viral load but an unchanged viral set point during viral rebound. The addition of an autologous stem cell transplant before cART withdrawal alters viral dynamics: we found a higher rebound set point but similar peak viral loads compared to the primary infection. Mathematical modeling of the data that accounts for fundamental immune parameters achieves excellent fit to heterogeneous viral loads. Analysis of model output suggests that the rapid memory immune response following treatment interruption does not ultimately lead to better viral containment. Transplantation decreases the durability of the adaptive immune response following cART withdrawal and viral rebound. Our model's results highlight the impact of the endogenous adaptive immune response during primary SHIV infection. Moreover, because we capture adaptive immune memory and the impact of transplantation, this model will provide insight into further studies of cure strategies inspired by the Berlin patient.IMPORTANCE HIV patients who interrupt combination antiretroviral therapy (cART) eventually experience viral rebound, the return of viral loads to pretreatment levels. However, the "Berlin patient" remained free of HIV rebound over a decade after stopping cART. His cure is attributed to leukemia treatment that included an HIV-resistant stem cell transplant. Inspired by this case, we studied the impact of stem cell transplantation in a macaque simian/HIV (SHIV) system. Using a mechanistic mathematical model, we found that while primary infection generates an adaptive immune memory response, stem cell transplantation disrupts this learned immunity. The results have implications for HIV cure regimens based on stem cell transplantation.
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Affiliation(s)
- Daniel B Reeves
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Christopher W Peterson
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Hans-Peter Kiem
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
- Department of Medicine, University of Washington, Seattle, Washington, USA
- Department of Pathology, University of Washington, Seattle, Washington, USA
| | - Joshua T Schiffer
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
- Department of Medicine, University of Washington, Seattle, Washington, USA
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19
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Errata. J Acquir Immune Defic Syndr 2016; 73:e66. [PMID: 27792687 DOI: 10.1097/qai.0000000000001197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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20
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In vitro functional assessment of natural HIV-1 group M Vpu sequences using a universal priming approach. J Virol Methods 2016; 240:32-41. [PMID: 27865749 DOI: 10.1016/j.jviromet.2016.11.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/04/2016] [Accepted: 11/08/2016] [Indexed: 01/06/2023]
Abstract
The HIV-1 accessory protein Vpu exhibits high inter- and intra- subtype genetic diversity that may influence Vpu function and possibly contribute to HIV-1 pathogenesis. However, scalable methods to evaluate genotype/phenotype relationships in natural Vpu sequences are limited, particularly those expressing the protein in CD4+ T-cells, the natural target of HIV-1 infection. A major impediment to assay scalability is the extensive genetic diversity within, and immediately upstream of, Vpu's initial 5' coding region, which has necessitated the design of oligonucleotide primers specific for each individual HIV-1 isolate (or subtype). To address this, we developed two universal forward primers, located in relatively conserved regions 38 and 90 bases upstream of Vpu, and a single universal reverse primer downstream of Vpu, which are predicted to cover the vast majority of global HIV-1 group M sequence diversity. We show that inclusion of up to 90 upstream bases of HIV-1 genomic sequence does not significantly influence in vitro Vpu expression or function when a Rev/Rev Response Element (RRE)-dependent expression system is used. We further assess the function of four diverse HIV-1 Vpu sequences, revealing reproducible and significant differences between them. Our approach represents a scalable option to measure the in vitro function of genetically diverse natural Vpu isolates in a CD4+ T-cell line.
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Abstract
Natural killer cells are a diverse group of innate lymphocytes that are specialized to rapidly respond to cancerous or virus-infected cells. NK cell function is controlled by the integration of signals from activating and inhibitory receptors expressed at the cell surface. Variegated expression patterns of these activating and inhibitory receptors at the single cell level leads to a highly diverse NK cell repertoire. Here I review the factors that influence NK cell repertoire diversity and its functional consequences for our ability to fight viruses.
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Affiliation(s)
- Catherine A Blish
- Department of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford, CA 94305 ; Immunology Program, Stanford University School of Medicine, Stanford, CA 94305
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22
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HIV-1 Vpu Antagonizes CD317/Tetherin by Adaptor Protein-1-Mediated Exclusion from Virus Assembly Sites. J Virol 2016; 90:6709-6723. [PMID: 27170757 DOI: 10.1128/jvi.00504-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/06/2016] [Indexed: 01/22/2023] Open
Abstract
UNLABELLED The host cell restriction factor CD317/tetherin traps virions at the surface of producer cells to prevent their release. The HIV-1 accessory protein Vpu antagonizes this restriction. Vpu reduces the cell surface density of the restriction factor and targets it for degradation; however, these activities are dispensable for enhancing particle release. Instead, Vpu has been suggested to antagonize CD317/tetherin by preventing recycling of internalized CD317/tetherin to the cell surface, blocking anterograde transport of newly synthesized CD317/tetherin, and/or displacing the restriction factor from virus assembly sites at the plasma membrane. At the molecular level, antagonism relies on the physical interaction of Vpu with CD317/tetherin. Recent findings suggested that phosphorylation of a diserine motif enables Vpu to bind to adaptor protein 1 (AP-1) trafficking complexes via two independent interaction motifs and to couple CD317/tetherin to the endocytic machinery. Here, we used a panel of Vpu proteins with specific mutations in individual interaction motifs to define which interactions are required for antagonism of CD317/tetherin. Impairing recycling or anterograde transport of CD317/tetherin to the plasma membrane was insufficient for antagonism. In contrast, excluding CD317/tetherin from HIV-1 assembly sites depended on Vpu motifs for interaction with AP-1 and CD317/tetherin and correlated with antagonism of the particle release restriction. Consistently, interference with AP-1 function or its expression blocked these Vpu activities. Our results define displacement from HIV-1 assembly sites as active principle of CD317/tetherin antagonism by Vpu and support a role of tripartite complexes between Vpu, AP-1, and CD317/tetherin in this process. IMPORTANCE CD317/tetherin poses an intrinsic barrier to human immunodeficiency virus type 1 (HIV-1) replication in human cells by trapping virus particles at the surface of producer cells and thereby preventing their release. The viral protein Vpu antagonizes this restriction, and molecular interactions with the restriction factor and adaptor protein complex 1 (AP-1) were suggested to mediate this activity. Vpu modulates intracellular trafficking of CD317/tetherin and excludes the restriction factor from HIV-1 assembly sites at the plasma membrane, but the relative contribution of these effects to antagonism remain elusive. Using a panel of Vpu mutants, as well as interference with AP-1 function and expression, we show here that Vpu antagonizes CD317/tetherin by blocking its recruitment to viral assembly sites in an AP-1-dependent manner. These results refine our understanding of the molecular mechanisms of CD317/tetherin antagonism and suggest complexes of Vpu with the restriction factor and AP-1 as targets for potential therapeutic intervention.
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