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Liu F, Wu X, Li L, Zou Y, Liu S, Wang Z. Evolutionary characteristics of morbilliviruses during serial passages in vitro: Gradual attenuation of virus virulence. Comp Immunol Microbiol Infect Dis 2016; 47:7-18. [DOI: 10.1016/j.cimid.2016.05.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 05/22/2016] [Accepted: 05/24/2016] [Indexed: 02/05/2023]
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Syller J, Grupa A. Antagonistic within-host interactions between plant viruses: molecular basis and impact on viral and host fitness. MOLECULAR PLANT PATHOLOGY 2016; 17:769-82. [PMID: 26416204 PMCID: PMC6638324 DOI: 10.1111/mpp.12322] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Double infections of related or unrelated viruses frequently occur in single plants, the viral agents being inoculated into the host plant simultaneously (co-infection) or sequentially (super-infection). Plants attacked by viruses activate sophisticated defence pathways which operate at different levels, often at significant fitness costs, resulting in yield reduction in crop plants. The occurrence and severity of the negative effects depend on the type of within-host interaction between the infecting viruses. Unrelated viruses generally interact with each other in a synergistic manner, whereas interactions between related viruses are mostly antagonistic. These can incur substantial fitness costs to one or both of the competitors. A relatively well-known antagonistic interaction is cross-protection, also referred to as super-infection exclusion. This type of interaction occurs when a previous infection with one virus prevents or interferes with subsequent infection by a homologous second virus. The current knowledge on why and how one virus variant excludes or restricts another is scant. Super-infection exclusion between viruses has predominantly been attributed to the induction of RNA silencing, which is a major antiviral defence mechanism in plants. There are, however, presumptions that various mechanisms are involved in this phenomenon. This review outlines the current state of knowledge concerning the molecular mechanisms behind antagonistic interactions between plant viruses. Harmful or beneficial effects of these interactions on viral and host plant fitness are also characterized. Moreover, the review briefly outlines the past and present attempts to utilize antagonistic interactions among viruses to protect crop plants against destructive diseases.
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Affiliation(s)
- Jerzy Syller
- Plant Breeding and Acclimatization Institute-National Research Institute, Laboratory of Phytopathology, Centre Młochów, 05-831, Młochów, Poland
| | - Anna Grupa
- Plant Breeding and Acclimatization Institute-National Research Institute, Laboratory of Phytopathology, Centre Młochów, 05-831, Młochów, Poland
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Retrospective on the all-in-one retroviral nucleocapsid protein. Virus Res 2014; 193:2-15. [PMID: 24907482 PMCID: PMC7114435 DOI: 10.1016/j.virusres.2014.05.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 05/11/2014] [Accepted: 05/11/2014] [Indexed: 01/08/2023]
Abstract
This retrospective reviews 30 years of research on the retroviral nucleocapsid protein (NC) focusing on HIV-1 NC. Originally considered as a non-specific nucleic-acid binding protein, NC has seminal functions in virus replication. Indeed NC turns out to be a all-in-one viral protein that chaperones viral DNA synthesis and integration, and virus formation. As a chaperone NC provides assistance to genetic recombination thus allowing the virus to escape the immune response and antiretroviral therapies against HIV-1.
This review aims at briefly presenting a retrospect on the retroviral nucleocapsid protein (NC), from an unspecific nucleic acid binding protein (NABP) to an all-in-one viral protein with multiple key functions in the early and late phases of the retrovirus replication cycle, notably reverse transcription of the genomic RNA and viral DNA integration into the host genome, and selection of the genomic RNA together with the initial steps of virus morphogenesis. In this context we will discuss the notion that NC protein has a flexible conformation and is thus a member of the growing family of intrinsically disordered proteins (IDPs) where disorder may account, at least in part, for its function as a nucleic acid (NA) chaperone and possibly as a protein chaperone vis-à-vis the viral DNA polymerase during reverse transcription. Lastly, we will briefly review the development of new anti-retroviral/AIDS compounds targeting HIV-1 NC because it represents an ideal target due to its multiple roles in the early and late phases of virus replication and its high degree of conservation.
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Keane NM, Roberts SG, Almeida CAM, Krishnan T, Chopra A, Demaine E, Laird R, Tschochner M, Carlson JM, Mallal S, Heckerman D, James I, John M. High-avidity, high-IFNγ-producing CD8 T-cell responses following immune selection during HIV-1 infection. Immunol Cell Biol 2012; 90:224-34. [PMID: 21577229 PMCID: PMC3173576 DOI: 10.1038/icb.2011.34] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
HIV-1 mutations, which reduce or abolish CTL responses against virus-infected cells, are frequently selected in acute and chronic HIV infection. Among population HIV-1 sequences, immune selection is evident as human leukocyte antigen (HLA) allele-associated substitutions of amino acids within or near CD8 T-cell epitopes. In these cases, the non-adapted epitope is susceptible to immune recognition until an escape mutation renders the epitope less immunogenic. However, several population-based studies have independently identified HLA-associated viral changes, which lead to the formation of a new T-cell epitope, suggesting that the immune responses that these variants or 'neo-epitopes' elicit provide an evolutionary advantage to the virus rather than the host. Here, we examined the functional characteristics of eight CD8 T-cell responses that result from viral adaptation in 125 HLA-genotyped individuals with chronic HIV-1 infection. Neo-epitopes included well-characterized immunodominant epitopes restricted by common HLA alleles, and in most cases the T-cell responses against the neo-epitope showed significantly greater functional avidity and higher IFNγ production than T cells for non-adapted epitopes, but were not more cytotoxic. Neo-epitope formation and emergence of cognate T-cell response coincident with a rise in viral load was then observed in vivo in an acutely infected individual. These findings show that HIV-1 adaptation not only abrogates the immune recognition of early targeted epitopes, but may also increase immune recognition to other epitopes, which elicit immunodominant but non-protective T-cell responses. These data have implications for immunodominance associated with polyvalent vaccines based on the diversity of chronic HIV-1 sequences.
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Affiliation(s)
- Niamh M Keane
- Centre for Clinical Immunology and Biomedical Statistics, Institute for Immunology and Infectious Diseases, Murdoch University, Perth, Western Australia, Australia
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Host Genomic Profiling in Human Immunodeficiency Virus Infection. Mol Microbiol 2011. [DOI: 10.1128/9781555816834.ch53] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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HIV-1 reverse transcriptase inhibitor resistance mutations and fitness: a view from the clinic and ex vivo. Virus Res 2008; 134:104-23. [PMID: 18289713 DOI: 10.1016/j.virusres.2007.12.021] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 12/27/2007] [Accepted: 12/28/2007] [Indexed: 01/04/2023]
Abstract
Genetic diversity plays a key role in human immunodeficiency virus (HIV) adaptation, providing a mechanism to escape host immune responses and develop resistance to antiretroviral drugs. This process is driven by the high-mutation rate during DNA synthesis by reverse transcriptase (RT), by the large viral populations, by rapid viral turnover, and by the high-recombination rate. Drugs targeting HIV RT are included in all regimens of highly active antiretroviral therapy (HAART), which helps to reduce the morbidity and mortality of HIV-infected patients. However, the emergence of resistant viruses is a significant obstacle to effective long-term management of HIV infection and AIDS. The increasing complexity of antiretroviral regimens has favored selection of HIV variants harboring multiple drug resistance mutations. Evolution of drug resistance is characterized by severe fitness losses when the drug is not present, which can be partially overcome by compensatory mutations or other adaptive changes that restore replication capacity. Here, we review the impact of mutations conferring resistance to nucleoside and nonnucleoside RT inhibitors on in vitro and in vivo fitness, their involvement in pathogenesis, persistence upon withdrawal of treatment, and transmission. We describe the techniques used to estimate viral fitness, the molecular mechanisms that help to improve the viral fitness of drug-resistant variants, and the clinical implications of viral fitness data, by exploring the potential relationship between plasma viral load, drug resistance, and disease progression.
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Palacios R, Viciana I, Pérez de Pedro I, de la Torre J, Ropero F, Fernández S, Salgado F, Roldán J, de Dios Colmenero J, Márquez M, Santos J. Prevalencia de mutaciones de resistencia primaria en los nuevos diagnósticos de infección por el VIH en la provincia de Málaga. Enferm Infecc Microbiol Clin 2008; 26:141-5. [DOI: 10.1157/13116750] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Herrera M, García-Arriaza J, Pariente N, Escarmís C, Domingo E. Molecular basis for a lack of correlation between viral fitness and cell killing capacity. PLoS Pathog 2007; 3:e53. [PMID: 17432933 PMCID: PMC1851977 DOI: 10.1371/journal.ppat.0030053] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2006] [Accepted: 02/27/2007] [Indexed: 11/19/2022] Open
Abstract
The relationship between parasite fitness and virulence has been the object of experimental and theoretical studies often with conflicting conclusions. Here, we provide direct experimental evidence that viral fitness and virulence, both measured in the same biological environment provided by host cells in culture, can be two unrelated traits. A biological clone of foot-and-mouth disease virus acquired high fitness and virulence (cell killing capacity) upon large population passages in cell culture. However, subsequent plaque-to-plaque transfers resulted in profound fitness loss, but only a minimal decrease of virulence. While fitness-decreasing mutations have been mapped throughout the genome, virulence determinants-studied here with mutant and chimeric viruses-were multigenic, but concentrated on some genomic regions. Therefore, we propose a model in which viral virulence is more robust to mutation than viral fitness. As a consequence, depending on the passage regime, viral fitness and virulence can follow different evolutionary trajectories. This lack of correlation is relevant to current models of attenuation and virulence in that virus de-adaptation need not entail a decrease of virulence.
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Affiliation(s)
- Mónica Herrera
- Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Cantoblanco, Madrid, Spain
| | - Juan García-Arriaza
- Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Cantoblanco, Madrid, Spain
| | - Nonia Pariente
- Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Cantoblanco, Madrid, Spain
| | - Cristina Escarmís
- Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Cantoblanco, Madrid, Spain
| | - Esteban Domingo
- Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Cantoblanco, Madrid, Spain
- * To whom correspondence should be addressed. E-mail:
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Darlix JL, Garrido JL, Morellet N, Mély Y, de Rocquigny H. Properties, functions, and drug targeting of the multifunctional nucleocapsid protein of the human immunodeficiency virus. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2007; 55:299-346. [PMID: 17586319 DOI: 10.1016/s1054-3589(07)55009-x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Jean-Luc Darlix
- LaboRetro, Unité INSERM de Virologie Humaine, IFR128, ENS Sciences de Lyon 46 allée d'Italie, Lyon, France
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Metzner KJ, Binley JM, Gettie A, Marx P, Nixon DF, Connor RI. Tenofovir treatment augments anti-viral immunity against drug-resistant SIV challenge in chronically infected rhesus macaques. Retrovirology 2006; 3:97. [PMID: 17184540 PMCID: PMC1769512 DOI: 10.1186/1742-4690-3-97] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Accepted: 12/21/2006] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Emergence of drug-resistant strains of human immunodeficiency virus type 1 (HIV-1) is a major obstacle to successful antiretroviral therapy (ART) in HIV-infected patients. Whether antiviral immunity can augment ART by suppressing replication of drug-resistant HIV-1 in humans is not well understood, but can be explored in non-human primates infected with simian immunodeficiency virus (SIV). Rhesus macaques infected with live, attenuated SIV develop robust SIV-specific immune responses but remain viremic, often at low levels, for periods of months to years, thus providing a model in which to evaluate the contribution of antiviral immunity to drug efficacy. To investigate the extent to which SIV-specific immune responses augment suppression of drug-resistant SIV, rhesus macaques infected with live, attenuated SIVmac239Deltanef were treated with the reverse transcriptase (RT) inhibitor tenofovir, and then challenged with pathogenic SIVmac055, which has a five-fold reduced sensitivity to tenofovir. RESULTS Replication of SIVmac055 was detected in untreated macaques infected with SIVmac239Deltanef, and in tenofovir-treated, naïve control macaques. The majority of macaques infected with SIVmac055 experienced high levels of plasma viremia, rapid CD4+ T cell loss and clinical disease progression. By comparison, macaques infected with SIVmac239Deltanef and treated with tenofovir showed no evidence of replicating SIVmac055 in plasma using allele-specific real-time PCR assays with a limit of sensitivity of 50 SIV RNA copies/ml plasma. These animals remained clinically healthy with stable CD4+ T cell counts during three years of follow-up. Both the tenofovir-treated and untreated macaques infected with SIVmac239Deltanef had antibody responses to SIV gp130 and p27 antigens and SIV-specific CD8+ T cell responses prior to SIVmac055 challenge, but only those animals receiving concurrent treatment with tenofovir resisted infection with SIVmac055. CONCLUSION These results support the concept that anti-viral immunity acts synergistically with ART to augment drug efficacy by suppressing replication of viral variants with reduced drug sensitivity. Treatment strategies that seek to combine immunotherapeutic intervention as an adjunct to antiretroviral drugs may therefore confer added benefit by controlling replication of HIV-1, and reducing the likelihood of treatment failure due to the emergence of drug-resistant virus, thereby preserving treatment options.
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Affiliation(s)
- Karin J Metzner
- Aaron Diamond AIDS Research Center and The Rockefeller University, New York, NY 10016, USA
- University of Erlangen-Nuremberg, Institute of Clinical and Molecular Virology, Schlossgarten 4, Erlangen, 91054, Germany
| | - James M Binley
- Torrey Pines Institute for Molecular Studies, San Diego, CA 92121, USA
| | - Agegnehu Gettie
- Tulane Regional Primate Research Center and Department of Tropical Medicine, Tulane University Health Sciences Center, Covington, LA 70433, USA
| | - Preston Marx
- Tulane Regional Primate Research Center and Department of Tropical Medicine, Tulane University Health Sciences Center, Covington, LA 70433, USA
| | - Douglas F Nixon
- University of California, San Francisco, Department of Medicine, Division of Experimental Medicine, San Francisco, CA 94110, USA
| | - Ruth I Connor
- Aaron Diamond AIDS Research Center and The Rockefeller University, New York, NY 10016, USA
- Department of Microbiology and Immunology, HB7556, Dartmouth-Hitchcock Medical Center, One Medical Center Drive, NH 03756, Lebanon
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Abstract
Management of infection with human immunodeficiency virus (HIV) improved dramatically during the 1990s. The advent of high-performance quantitative HIV assays and highly active antiretroviral therapy were the two most important developments in HIV medicine. As a result, HIV mortality and morbidity have reduced significantly, although a proportion of HIV-infected patients are still diagnosed late. Management of HIV during pregnancy has also improved so that vertical transmission is now limited to less than 2% of all cases. Knowledge of the different stages of HIV infection enables optimal timing of start of antiretroviral therapy. Routine offering of HIV testing might also reduce the number of patients diagnosed with immunodeficiency. Better knowledge of the life cycle of HIV has made it possible to design new classes of antiretroviral drugs. The new drugs, however, pose new challenges as they might have long-term side effects. In addition, their interactions with other antiretroviral drugs might not be favourable.
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Affiliation(s)
- Kaveh Manavi
- Department of Genitourinary Medicine, Whittall Street Clinic, Whittall Street, Birmingham, B4 6DH, UK.
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Khan AS, Kumar D. Simian foamy virus infection by whole-blood transfer in rhesus macaques: potential for transfusion transmission in humans. Transfusion 2006; 46:1352-9. [PMID: 16934071 DOI: 10.1111/j.1537-2995.2006.00862.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Cross-species infection of humans with simian foamy virus (SFV) has been reported in European and North American nonhuman primate (NHP) handlers, primarily due to wound injuries involving infected animals in research centers and zoos. Additionally, African hunters have been found to be infected with SFV by exposure to body fluids, blood, or tissues of infected NHPs in the wild. The persistence of infectious virus in peripheral blood mononuclear cells (PBMNC) and the recent identification of some infected blood donors has raised safety concerns regarding potential virus transmission by blood transfusion. STUDY DESIGN AND METHODS SFV infection by blood transfusion was evaluated by whole-blood transfer from two naturally-infected rhesus macaques (designated as D1 and D2) to retrovirus-free monkeys. Blood from D1 was transfused to two recipient monkeys R1 and R2 and from D2 to monkeys R3 and R4. Virus transmission was evaluated by immunoassays, polymerase chain reaction assays, and coculture of PBMNC for SFV isolation. RESULTS SFV infection was seen in R1 and R2 based on development of virus-specific antibodies, identification of SFV sequences in monkey PBMNC, and isolation of infectious virus from PBMNC. Furthermore, both R1 and R2 remained SFV-positive at about 1 year after transfusion, which was the last time tested. No evidence of SFV infection was seen in R3 and R4. CONCLUSION SFV transmission in macaques occurred by transfusion of blood from one of two infected donor animals. These results indicate the potential of SFV transfusion transmission in humans, which may depend on virus-specific or donor-related factors.
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Affiliation(s)
- Arifa S Khan
- Laboratory of Retrovirus Research, Division of Viral Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Bethesda, Maryland, USA.
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