المؤلفون: Jan Münch, Janis A. Müller, Ali Gawanbacht, Frank Kirchhoff, Anna Glöckle, Matthias Geyer

المصدر: Journal of Virology

مصطلحات موضوعية: 0301 basic medicine, Receptors, CCR5, 030106 microbiology, Immunology, HIV Infections, Endogeny, Biology, Gp41, Microbiology, CXCR4, 03 medical and health sciences, Viral envelope, HIV Fusion Inhibitors, Virology, Humans, Infectivity, chemistry.chemical_classification, Virus Internalization, HIV Envelope Protein gp41, Peptide Fragments, Virus-Cell Interactions, HEK293 Cells, 030104 developmental biology, chemistry, Cell culture, alpha 1-Antitrypsin, Insect Science, Mutation, HIV-1, Genetic Fitness, Glycoprotein, Viral load

الوصف: VIRIP has been identified as natural HIV-1 inhibitor targeting the gp41 fusion peptide. An optimized analogue (VIR-576) was effective in a phase I/II clinical trial and initial studies showed that HIV-1 resistance to VIRIP-based inhibitors has a high genetic barrier. Partially resistant CXCR4 (X4)-tropic HIV-1 NL4-3 variants could be obtained, however, after more than 15 months of passaging in MT-4 cells in the presence of another derivative (VIR-353). Sequence analyses identified the accumulation of seven mutations across the HIV-1 envelope glycoprotein but outside the gp41 fusion peptide. The authors suggested that the three initial alterations conferred resistance, while subsequent changes restored viral fitness. Here, we introduced these mutations individually and in combination into X4- and CCR5 (R5)-tropic HIV-1 constructs and determined their impact on VIR-353 and VIR-576 susceptibility, viral infectivity, replication fitness, and fusogenicity. We found that essentially all seven mutations contribute to reduced susceptibility to VIRIP-based inhibitors. HIV-1 constructs containing ≥4 changes were substantially more resistant to both VIRIP-based inhibitors and the VRC34.01 antibody targeting the fusion peptide. However, they were also much less infectious and fusogenic than those harboring only the three initial alterations. Furthermore, the additional changes attenuated rather than rescued HIV-1 replication in primary human cells. Thus, the genetic barrier to HIV-1 resistance against VIRIP-based inhibitors is higher than previously suggested, and mutations reducing viral susceptibility come at a severe fitness cost that was not rescued during long-term cell culture passage.IMPORTANCE Many viral pathogens are critically dependent on fusion peptides (FPs) that are inserted into the cellular membrane for infection. Initially, it was thought that FPs cannot be targeted for therapy because they are hardly accessible. However, an optimized derivative (VIR-576) of an endogenous fragment of α1-antitrypsin, named VIRIP, targeting the gp41 FP reduced viral loads in HIV-1-infected individuals. Characterization of HIV-1 variants selected during long-term cell-culture passage in the presence of a VIRIP derivative suggested that just three mutations in the HIV-1 Env protein might be sufficient for VIRIP resistance and that four subsequent changes restored viral fitness. Here, we show that all seven mutations contribute to reduced viral susceptibility to VIRIP-based inhibitors and demonstrate that the additional changes strongly impair rather than rescue HIV-1 infectivity, fusogenicity, and replication fitness. High genetic barrier to resistance and severe fitness cost support further clinical development of this class of antiviral agents.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f045e20e8254d02d5540aa65a4f57bcaTest
https://doi.org/10.1128/jvi.00733-18Test

المؤلفون: Ali Gawanbacht, Eric J. Lee, Jacob Piehler, Jens Verheyen, Janis A. Müller, Brent Race, Mario L. Santiago, Sandra Francois, Cara C. Wilson, Kim J. Hasenkrug, Ronald J. Messer, Karin E. Peterson, Michael S. Harper, Kejun Guo, Katie Phillips, Jan Münch, Hartmut Hengel, Ulf Dittmer, Kathrin Gibbert, Erik Van Dis, Tyson A. Woods, Mirko Trilling, Kerry J. Lavender

المصدر: Journal of Virology. 90:6001-6013

مصطلحات موضوعية: Myxovirus Resistance Proteins, 0301 basic medicine, Combination therapy, Immunology, Medizin, Antiviral protein, Alpha interferon, HIV Infections, Mice, Transgenic, Viremia, APOBEC-3G Deaminase, CD8-Positive T-Lymphocytes, Biology, GPI-Linked Proteins, Lymphocyte Activation, Virus Replication, Antiviral Agents, Microbiology, Virus, Mice, 03 medical and health sciences, Immune system, Antigens, CD, Virology, Vaccines and Antiviral Agents, medicine, Animals, Humans, Interferon-alpha, virus diseases, Viral Load, medicine.disease, Immunity, Innate, Killer Cells, Natural, 030104 developmental biology, Viral replication, Insect Science, Disease Progression, HIV-1, Viral load

الوصف: Although all 12 subtypes of human interferon alpha (IFN-α) bind the same receptor, recent results have demonstrated that they elicit unique host responses and display distinct efficacies in the control of different viral infections. The IFN-α2 subtype is currently in HIV-1 clinical trials, but it has not consistently reduced viral loads in HIV-1 patients and is not the most effective subtype against HIV-1 in vitro . We now demonstrate in humanized mice that, when delivered at the same high clinical dose, the human IFN-α14 subtype has very potent anti-HIV-1 activity whereas IFN-α2 does not. In both postexposure prophylaxis and treatment of acute infections, IFN-α14, but not IFN-α2, significantly suppressed HIV-1 replication and proviral loads. Furthermore, HIV-1-induced immune hyperactivation, which is a prognosticator of disease progression, was reduced by IFN-α14 but not IFN-α2. Whereas ineffective IFN-α2 therapy was associated with CD8 + T cell activation, successful IFN-α14 therapy was associated with increased intrinsic and innate immunity, including significantly higher induction of tetherin and MX2, increased APOBEC3G signature mutations in HIV-1 proviral DNA, and higher frequencies of TRAIL + NK cells. These results identify IFN-α14 as a potent new therapeutic that operates via mechanisms distinct from those of antiretroviral drugs. The ability of IFN-α14 to reduce both viremia and proviral loads in vivo suggests that it has strong potential as a component of a cure strategy for HIV-1 infections. The broad implication of these results is that the antiviral efficacy of each individual IFN-α subtype should be evaluated against the specific virus being treated. IMPORTANCE The naturally occurring antiviral protein IFN-α2 is used to treat hepatitis viruses but has proven rather ineffective against HIV in comparison to triple therapy with the antiretroviral (ARV) drugs. Although ARVs suppress the replication of HIV, they fail to completely clear infections. Since IFN-α acts by different mechanism than ARVs and has been shown to reduce HIV proviral loads, clinical trials are under way to test whether IFN-α2 combined with ARVs might eradicate HIV-1 infections. IFN-α is actually a family of 12 distinct proteins, and each IFN-α subtype has different efficacies toward different viruses. Here, we use mice that contain a human immune system, so they can be infected with HIV. With this model, we demonstrate that while IFN-α2 is only weakly effective against HIV, IFN-α14 is extremely potent. This discovery identifies IFN-α14 as a more powerful IFN-α subtype for use in combination therapy trials aimed toward an HIV cure.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::6568c37792337023ed8f1abfef52d049Test
https://doi.org/10.1128/jvi.00451-16Test

المؤلفون: Shariq M. Usmani, Mohammad Khalid, Guido Silvestri, Jan Münch, Hangxing Yu, Johannes A. van der Merwe, Anke Heigele, Jan Schmökel, Frank Kirchhoff

المصدر: Journal of Virology

مصطلحات موضوعية: CD4-Positive T-Lymphocytes, CD3 Complex, Cell Survival, viruses, T cell, Immunology, Receptors, Antigen, T-Cell, Apoptosis, Streptamer, Biology, Microbiology, Interleukin 21, Immune system, Antigen, T-Lymphocyte Subsets, Virology, medicine, Animals, Humans, Cytotoxic T cell, nef Gene Products, Human Immunodeficiency Virus, IL-2 receptor, Antigen-presenting cell, virus diseases, Virus-Cell Interactions, 3. Good health, medicine.anatomical_structure, Insect Science, HIV-1, Leukocyte Common Antigens

الوصف: The role of the accessory viral Nef protein as a multifunctional manipulator of the host cell that is required for effective replication of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) in vivo is well established. It is unknown, however, whether Nef manipulates all or just specific subsets of CD4 + T cells, which are the main targets of virus infection and differ substantially in their state of activation and importance for a functional immune system. Here, we analyzed the effect of Nef proteins differing in their T cell receptor (TCR)-CD3 downmodulation function in HIV-infected human lymphoid aggregate cultures and peripheral blood mononuclear cells. We found that Nef efficiently downmodulates TCR-CD3 in naive and memory CD4 + T cells and protects the latter against apoptosis. In contrast, highly proliferative CD45RA + CD45RO + CD4 + T cells were main producers of infectious virus but largely refractory to TCR-CD3 downmodulation. Such T cell subset-specific differences were also observed for Nef-mediated modulation of CD4 but not for enhancement of virion infectivity. Our results indicate that Nef predominantly modulates surface receptors on CD4 + T cell subsets that are not already fully permissive for viral replication. As a consequence, Nef-mediated downmodulation of TCR-CD3, which distinguishes most primate lentiviruses from HIV type 1 (HIV-1) and its vpu -containing simian precursors, may promote a selective preservation of central memory CD4 + T cells, which are critical for the maintenance of a functional immune system. IMPORTANCE The Nef proteins of human and simian immunodeficiency viruses manipulate infected CD4 + T cells in multiple ways to promote viral replication and immune evasion in vivo . Here, we show that some effects of Nef are subset specific. Downmodulation of CD4 and TCR-CD3 is highly effective in central memory CD4 + T cells, and the latter Nef function protects this T cell subset against apoptosis. In contrast, highly activated/proliferating CD4 + T cells are largely refractory to receptor downmodulation but are main producers of infectious HIV-1. Nef-mediated enhancement of virion infectivity, however, was observed in all T cell subsets examined. Our results provide new insights into how primate lentiviruses manipulate their target cells and suggest that the TCR-CD3 downmodulation function of Nef may promote a selective preservation of memory CD4 + T cells, which are critical for immune function, but has little effect on activated/proliferating CD4 + T cells, which are the main targets for viral replication.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::498b0e665ddd9f18ceebb3755f6faa41Test
https://doi.org/10.1128/jvi.03104-14Test

المؤلفون: Jan Münch, Jason Neidleman, Aram Avila-Herrera, Haichuan Liu, H. E. Witkowska, Warner C. Greene, Senthil Kumar, James F. Smith, Ali Gawanbacht, Nadia R. Roan, Simon Chu, Shariq M. Usmani, Marcus Fändrich, Onofrio Zirafi, Ming Dong, Katherine S. Pollard, Frank Kirchhoff, Janis A. Müller

المساهمون: Hahn, BH

المصدر: Journal of virology, vol 88, iss 13

مصطلحات موضوعية: Amyloid, Proteases, Proteolysis, Blotting, Western, Molecular Sequence Data, Immunology, Sequence Homology, HIV Infections, Semen, Biology, Seminal Vesicle Secretory Proteins, Medical and Health Sciences, Microbiology, Serine, Clinical Research, Virology, medicine, Humans, Amino Acid Sequence, Peptide sequence, Phylogeny, Agricultural and Veterinary Sciences, Sequence Homology, Amino Acid, medicine.diagnostic_test, Blotting, Liquefaction, Biological Sciences, Virus Internalization, Peptide Fragments, Virus-Cell Interactions, Amino Acid, Infectious Diseases, Biochemistry, Insect Science, HIV-1, HIV/AIDS, Infection, Western, Semenogelin

الوصف: Semen enhances HIV infection in vitro , but how long it retains this activity has not been carefully examined. Immediately postejaculation, semen exists as a semisolid coagulum, which then converts to a more liquid form in a process termed liquefaction. We demonstrate that early during liquefaction, semen exhibits maximal HIV-enhancing activity that gradually declines upon further incubation. The decline in HIV-enhancing activity parallels the degradation of peptide fragments derived from the semenogelins (SEMs), the major components of the coagulum that are cleaved in a site-specific and progressive manner upon initiation of liquefaction. Because amyloid fibrils generated from SEM fragments were recently demonstrated to enhance HIV infection, we set out to determine whether any of the liquefaction-generated SEM fragments associate with the presence of HIV-enhancing activity. We identify SEM1 from amino acids 86 to 107 [SEM1(86-107)] to be a short, cationic, amyloidogenic SEM peptide that is generated early in the process of liquefaction but that, conversely, is lost during prolonged liquefaction due to the activity of serine proteases. Synthetic SEM1(86-107) amyloids directly bind HIV-1 virions and are sufficient to enhance HIV infection of permissive cells. Furthermore, endogenous seminal levels of SEM1(86-107) correlate with donor-dependent variations in viral enhancement activity, and antibodies generated against SEM1(86-107) recognize endogenous amyloids in human semen. The amyloidogenic potential of SEM1(86-107) and its virus-enhancing properties are conserved among great apes, suggesting an evolutionarily conserved function. These studies identify SEM1(86-107) to be a key, HIV-enhancing amyloid species in human semen and underscore the dynamic nature of semen's HIV-enhancing activity. IMPORTANCE Semen, the most common vehicle for HIV transmission, enhances HIV infection in vitro , but how long it retains this activity has not been investigated. Semen naturally undergoes physiological changes over time, whereby it converts from a gel-like consistency to a more liquid form. This process, termed liquefaction, is characterized at the molecular level by site-specific and progressive cleavage of SEMs, the major components of the coagulum, by seminal proteases. We demonstrate that the HIV-enhancing activity of semen gradually decreases over the course of extended liquefaction and identify a naturally occurring semenogelin-derived fragment, SEM1(86-107), whose levels correlate with virus-enhancing activity over the course of liquefaction. SEM1(86-107) amyloids are naturally present in semen, and synthetic SEM1(86-107) fibrils bind virions and are sufficient to enhance HIV infection. Therefore, by characterizing dynamic changes in the HIV-enhancing activity of semen during extended liquefaction, we identified SEM1(86-107) to be a key virus-enhancing component of human semen.

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::dc5f306eb6041628968eec4bd551a1aaTest
https://doi.org/10.1128/jvi.00269-14Test

المؤلفون: Jan Münch, Mark A. Wainberg, Thibault Mesplède, Daniel A. Donahue, Björn D. Kuhl, Richard D Sloan

المصدر: Journal of Virology. 87:8110-8123

مصطلحات موضوعية: CD4-Positive T-Lymphocytes, Dynamins, Endosome, Immunology, Endocytic cycle, HIV Infections, Endocytosis, Models, Biological, Microbiology, Clathrin, Jurkat cells, Jurkat Cells, Viral entry, Virology, Vaccines and Antiviral Agents, Humans, Dynamin, biology, Virus Internalization, Cell biology, HEK293 Cells, Monomeric Clathrin Assembly Proteins, Insect Science, HIV-1, Leukocytes, Mononuclear, biology.protein, Ap180, RNA Interference

الوصف: HIV-1 can be transmitted as cell-free virus or via cell-to-cell contacts. Cell-to-cell transmission between CD4 + T cells is the more efficient mode of transmission and is predominant in lymphoid tissue, where the majority of virus resides. Yet the cellular mechanisms underlying productive cell-to-cell transmission in uninfected target cells are unclear. Although it has been demonstrated that target cells can take up virus via endocytosis, definitive links between this process and productive infection remain undefined, and this route of transmission has been proposed to be nonproductive. Here, we report that productive cell-to-cell transmission can occur via endocytosis in a dynamin-dependent manner and is sensitive to clathrin-associated antagonists. These data were obtained in a number of CD4 + T-cell lines and in primary CD4 + T cells, using both CXCR4- and CCR5-tropic virus. However, we also found that HIV-1 demonstrated flexibility in its use of such endocytic pathways as certain allogeneic transmissions were seen to occur in a dynamin-dependent manner but were insensitive to clathrin-associated antagonists. Also, depleting cells of the clathrin accessory protein AP180 led to a viral uptake defect associated with enhanced infection. Collectively, these data demonstrate that endosomal uptake of HIV-1 during cell-to-cell transmission leads to productive infection, but they are also indicative of a flexible model of viral entry during cell-to-cell transmission, in which the virus can alter its entry route according to the pressures that it encounters.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::468eefa4b2214c87380ca90e3d5ee129Test
https://doi.org/10.1128/jvi.00815-13Test

المؤلفون: Jacqueline Schnell, Wolf-Georg Forssmann, Ludger Ständker, Frank Kirchhoff, Christoph Meier, Nadia R. Roan, Onofrio Zirafi, Jan Münch, Franziska Arnold, Tanja Weil, Warner C. Greene, Christina M. Stürzel

المصدر: Journal of Virology

مصطلحات موضوعية: Male, Amyloid, Acid Phosphatase, Amino Acid Motifs, Molecular Sequence Data, Immunology, Human immunodeficiency virus (HIV), Virus Attachment, HIV Infections, Semen, Peptide, Biology, medicine.disease_cause, Microbiology, Cell Line, Virology, medicine, Humans, Amino Acid Sequence, Vector (molecular biology), Enhancer, Hiv transmission, chemistry.chemical_classification, Molecular biology, Peptide Fragments, Virus-Cell Interactions, Biochemistry, Prostatic acid phosphatase, chemistry, Insect Science, HIV-1, Protein Tyrosine Phosphatases, Sequence Alignment

الوصف: Semen is the major vector for HIV-1 transmission. We previously isolated C-proximal fragments of the prostatic acid phosphatase (PAP) from semen which formed amyloid fibrils that potently enhanced HIV infection. Here, we used the same methodology and identified another amyloidogenic peptide. Surprisingly, this peptide is derived from an N-proximal fragment of PAP (PAP85-120) and forms, similar to the C-proximal fragments, positively charged fibrillar structures that increase virion attachment to cells. Our results provide a first example for amyloid formation by fragments of distinct regions of the same precursor and further emphasize the possible importance of amyloidogenic peptides in HIV transmission.

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::19678d65c604fe0862ef68899a15b6d1Test
https://doi.org/10.1128/jvi.06121-11Test

المؤلفون: Maria G. Salazar, Frank Kirchhoff, Clement W. Gnanadurai, Ivona Pandrea, Gerald H. Learn, Christiane Stahl-Hennig, Jan Münch, Rajeev Gautam, Matthias H. Kraus, Christian Apetrei, Ulrike Sauermann, Nicholas F. Parrish, Beatrice H. Hahn, Katharina Töpfer

المصدر: Journal of Virology. 84:12245-12254

مصطلحات موضوعية: CD4-Positive T-Lymphocytes, viruses, Blotting, Western, Molecular Sequence Data, Immunology, Simian Acquired Immunodeficiency Syndrome, Viremia, Genome, Viral, Virus Replication, medicine.disease_cause, Polymerase Chain Reaction, Microbiology, Virus, law.invention, Cercopithecinae, law, Virology, medicine, Animals, Cluster Analysis, Cloning, Molecular, Phylogeny, Polymerase chain reaction, DNA Primers, Base Sequence, biology, Sequence Analysis, DNA, Nucleic acid amplification technique, Simian immunodeficiency virus, Flow Cytometry, biology.organism_classification, medicine.disease, Phenotype, Viral replication, Insect Science, Lentivirus, Disease Progression, Pathogenesis and Immunity, Simian Immunodeficiency Virus, African Green Monkey, Nucleic Acid Amplification Techniques

الوصف: Understanding the lack of disease progression in nonpathogenic simian immunodeficiency virus (SIV) infections is essential for deciphering the immunopathogenesis of human AIDS. Yet, in vivo studies have been hampered by a paucity of infectious molecular clones (IMCs) of SIV suitable to dissect the viral and host factors responsible for the nonpathogenic phenotype. Here, we describe the identification, cloning, and biological analysis of the first transmitted/founder (T/F) virus representing a nonpathogenic SIV infection. Blood was collected at peak viremia from an acutely infected sabaeus monkey ( Chlorocebus sabaeus ) inoculated intravenously with an African green monkey SIV (SIVagm) strain (Sab92018) that had never been propagated in vitro . To generate IMCs, we first used conventional (bulk) PCR to amplify full-length viral genomes from peripheral blood mononuclear cell (PBMC) DNA. Although this yielded two intact SIVagmSab genomes, biological characterization revealed that both were replication defective. We then performed single-genome amplification (SGA) to generate partially overlapping 5′ ( n = 10) and 3′ ( n = 13) half genomes from plasma viral RNA. Analysis of these amplicons revealed clusters of nearly identical viral sequences representing the progeny of T/F viruses. Synthesis of the consensus sequence of one of these generated an IMC (Sab92018ivTF) that produced infectious CCR5-tropic virions and replicated to high titers in Molt-4 clone 8 cells and African green monkey PBMCs. Sab92018ivTF also initiated productive infection in sabaeus monkeys and faithfully recapitulated the replication kinetics and nonpathogenic phenotype of the parental Sab92018 strain. These results thus extend the T/F virus concept to nonpathogenic SIV infections and provide an important new tool to define viral determinants of disease nonprogression.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::2227b7e5753df9667398a567ddee9c56Test
https://doi.org/10.1128/jvi.01603-10Test

المؤلفون: Jaydip Das Gupta, Robert H. Silverman, Kirsten Hanke, Christina Gaughan, Kyeong Ae Kim, Jan Münch, Eric A. Klein, Christopher J. Weight, Carvell T. Nguyen, Norbert Bannert, Seunghee Hong, Frank Kirchhoff

المصدر: Journal of Virology. 83:6995-7003

مصطلحات موضوعية: Male, viruses, Acid Phosphatase, Immunology, Population, urologic and male genital diseases, Microbiology, Transformation and Oncogenesis, Virus, Xenotropic murine leukemia virus-related virus, Prostate cancer, Retrovirus, Cell Line, Tumor, Virology, Murine leukemia virus, medicine, Humans, education, Cells, Cultured, Gammaretrovirus, education.field_of_study, biology, Prostatic Neoplasms, virus diseases, Fibroblasts, biology.organism_classification, medicine.disease, Prostatic acid phosphatase, Insect Science, Protein Tyrosine Phosphatases, Retroviridae Infections

الوصف: The xenotropic murine leukemia virus-related virus (XMRV) has recently been detected in prostate cancer tissues and may play a role in tumorigenesis. It is currently unclear how this virus is transmitted and which factors promote its spread in the prostate. We show that amyloidogenic fragments known as semen-derived enhancer of virus infection (SEVI) originating from prostatic acid phosphatase greatly increase XMRV infections of primary prostatic epithelial and stromal cells. Hybrid simian/human immunodeficiency chimeric virus particles pseudotyped with XMRV envelope protein were used to demonstrate that the enhancing effect of SEVI, or of human semen itself, was at the level of viral attachment and entry. SEVI enhanced XMRV infectivity but did not bypass the requirement for the xenotropic and polytropic retrovirus receptor 1. Furthermore, XMRV RNA was detected in prostatic secretions of some men with prostate cancer. The fact that the precursor of SEVI is produced in abundance by the prostate indicates that XMRV replication occurs in an environment that provides a natural enhancer of viral infection, and this may play a role in the spread of this virus in the human population.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::4c4eadac599e5c3960c86417adcb8e10Test
https://doi.org/10.1128/jvi.00268-09Test

المؤلفون: Nicole Studtrucker, Jörg Votteler, Torgils Fossen, Elke Rücker, Peter Henklein, Alok Sharma, Victor Wray, Stefan Sörgel, Karsten Bruns, Frank Kirchhoff, Jan Münch, Bernhard Schick, Ulrich S. Schubert

المصدر: Journal of Virology. 81:9572-9576

مصطلحات موضوعية: Conformational change, Magnetic Resonance Spectroscopy, Proline, Lymphoid Tissue, viruses, Molecular Sequence Data, Immunology, Biology, Virus Replication, medicine.disease_cause, Microbiology, Protein Structure, Secondary, Virus, Virology, medicine, Humans, Amino Acid Sequence, Peptide sequence, Mutation, Gene Products, vpr, Virus Assembly, virus diseases, vpr Gene Products, Human Immunodeficiency Virus, biochemical phenomena, metabolism, and nutrition, Subcellular localization, Virus-Cell Interactions, Amino Acid Substitution, Viral replication, Apoptosis, Insect Science, HIV-1, Mutagenesis, Site-Directed, Ex vivo, HeLa Cells

الوصف: Mutational analysis of the four conserved proline residues in human immunodeficiency virus type 1 (HIV-1) Vpr reveals that only Pro-35 is required for efficient replication of R5-tropic, but not of X4-tropic, viruses in human lymphoid tissue (HLT) cultivated ex vivo. While Vpr-mediated apoptosis and G 2 cell cycle arrest, as well as the expression and subcellular localization of Vpr, were independent, the capacity for encapsidation of Vpr into budding virions was dependent on Pro-35. 1 H nuclear magnetic resonance data suggest that mutation of Pro-35 causes a conformational change in the hydrophobic core of the molecule, whose integrity is required for the encapsidation of Vpr, and thus, Pro-35 supports the replication of R5-tropic HIV-1 in HLT.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::6c59a9cf205cdc0d7ebd01b2cfb4d376Test
https://doi.org/10.1128/jvi.02803-06Test

المؤلفون: Jan Münch, Raghavan Chinnadurai, Devi Rajan, Frank Kirchhoff

المصدر: Journal of Virology. 81:6563-6572

مصطلحات موضوعية: CD4-Positive T-Lymphocytes, Enfuvirtide, Lymphoid Tissue, viruses, Amino Acid Motifs, Molecular Sequence Data, Immunology, Mutant, Plasma protein binding, Biology, Gp41, Microbiology, Virus, HIV Fusion Inhibitors, Viral entry, Virology, Vaccines and Antiviral Agents, Drug Resistance, Viral, medicine, Humans, Amino Acid Sequence, Codon, Base Sequence, HIV Envelope Protein gp41, Protein Structure, Tertiary, Heptad repeat, Insect Science, Mutation, HIV-1, Ex vivo, Protein Binding, medicine.drug

الوصف: Human immunodeficiency virus type 1 (HIV-1) fusion inhibitors blocking viral entry by binding the gp41 heptad repeat 1 (HR1) region offer great promise for antiretroviral therapy, and the first of these inhibitors, T20 (Fuzeon; enfuvirtide), is successfully used in the clinic. It has been reported previously that changes in the 3-amino-acid GIV motif at positions 36 to 38 of gp41 HR1 mediate resistance to T20 but usually not to second-version fusion inhibitors, such as T1249, which target an overlapping but distinct region in HR1 including a conserved hydrophobic pocket (HP). Based on the common lack of cross-resistance and the difficulty of selecting T1249-resistant HIV-1 variants, it has been suggested that the determinants of resistance to first- and second-version fusion inhibitors may be different. To further assess HIV-1 resistance to fusion inhibitors and to analyze where changes in HR1 are tolerated, we randomized 16 codons in the HR1 region, including those making contact with HR2 codons and/or encoding residues in the GIV motif and the HP. We found that changes only at positions 37I, 38V, and 40Q near the N terminus of HR1 were tolerated. The propagation of randomly gp41-mutated HIV-1 variants in the presence of T1249 allowed the effective selection of highly resistant forms, all containing changes in the IV residues. Overall, the extent of T1249 resistance was inversely correlated to viral fitness and cytopathicity. Notably, one HIV-1 mutant showing ∼10-fold-reduced susceptibility to T1249 inhibition replicated with wild type-like kinetics and caused substantial CD4 + -T-cell depletion in ex vivo-infected human lymphoid tissue in the presence and absence of an inhibitor. Taken together, our results show that the GIV motif also plays a key role in resistance to second-version fusion inhibitors and suggest that some resistant HIV-1 variants may be pathogenic in vivo.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::04d0982dd4b2658b51c41fc2140a4270Test
https://doi.org/10.1128/jvi.02546-06Test