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Le Guillou-Guillemette H, Pivert A, Bouthry E, Henquell C, Petsaris O, Ducancelle A, Veillon P, Vallet S, Alain S, Thibault V, Abravanel F, Rosenberg AA, André-Garnier E, Bour JB, Baazia Y, Trimoulet P, André P, Gaudy-Graffin C, Bettinger D, Larrat S, Signori-Schmuck A, Saoudin H, Pozzetto B, Lagathu G, Minjolle-Cha S, Stoll-Keller F, Pawlotsky JM, Izopet J, Payan C, Lunel-Fabiani F, Lemaire C. Natural non-homologous recombination led to the emergence of a duplicated V3-NS5A region in HCV-1b strains associated with hepatocellular carcinoma. PLoS One 2017; 12:e0174651. [PMID: 28394908 PMCID: PMC5386276 DOI: 10.1371/journal.pone.0174651] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 03/13/2017] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND The emergence of new strains in RNA viruses is mainly due to mutations or intra and inter-genotype homologous recombination. Non-homologous recombinations may be deleterious and are rarely detected. In previous studies, we identified HCV-1b strains bearing two tandemly repeated V3 regions in the NS5A gene without ORF disruption. This polymorphism may be associated with an unfavorable course of liver disease and possibly involved in liver carcinogenesis. Here we aimed at characterizing the origin of these mutant strains and identifying the evolutionary mechanism on which the V3 duplication relies. METHODS Direct sequencing of the entire NS5A and E1 genes was performed on 27 mutant strains. Quasispecies analyses in consecutive samples were also performed by cloning and sequencing the NS5A gene for all mutant and wild strains. We analyzed the mutant and wild-type sequence polymorphisms using Bayesian methods to infer the evolutionary history of and the molecular mechanism leading to the duplication-like event. RESULTS Quasispecies were entirely composed of exclusively mutant or wild-type strains respectively. Mutant quasispecies were found to have been present since contamination and had persisted for at least 10 years. This V3 duplication-like event appears to have resulted from non-homologous recombination between HCV-1b wild-type strains around 100 years ago. The association between increased liver disease severity and these HCV-1b mutants may explain their persistence in chronically infected patients. CONCLUSIONS These results emphasize the possible consequences of non-homologous recombination in the emergence and severity of new viral diseases.
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Affiliation(s)
- Hélène Le Guillou-Guillemette
- Laboratoire de Virologie, CHU Angers, France
- HIFIH Laboratory, UPRES 3859, SFR 4208, LUNAM University, Angers, France
| | - Adeline Pivert
- Laboratoire de Virologie, CHU Angers, France
- HIFIH Laboratory, UPRES 3859, SFR 4208, LUNAM University, Angers, France
| | - Elise Bouthry
- Laboratoire de Virologie, CHU Angers, France
- HIFIH Laboratory, UPRES 3859, SFR 4208, LUNAM University, Angers, France
| | | | - Odile Petsaris
- Département de Bactériologie-Virologie-Hygiène Hospitalière et Parasitologie-Mycologie, CHRU, LUBEM, Brest, France
| | - Alexandra Ducancelle
- Laboratoire de Virologie, CHU Angers, France
- HIFIH Laboratory, UPRES 3859, SFR 4208, LUNAM University, Angers, France
| | - Pascal Veillon
- Laboratoire de Virologie, CHU Angers, France
- HIFIH Laboratory, UPRES 3859, SFR 4208, LUNAM University, Angers, France
| | - Sophie Vallet
- Département de Bactériologie-Virologie-Hygiène Hospitalière et Parasitologie-Mycologie, CHRU, LUBEM, Brest, France
| | | | | | - Florence Abravanel
- Laboratoire de Virologie, CNR VHE, Inserm U1043, CHU Purpan, Toulouse, France
| | - Arielle A. Rosenberg
- AP-HP, GHU Cochin, Laboratoire de Virologie, Université Paris Descartes, Paris, France
| | | | | | - Yazid Baazia
- Laboratoire de Virologie, CHU Avicenne, Bobigny, France
| | - Pascale Trimoulet
- Laboratoire de Virologie, Hôpital Pellegrin Tripode, CHU Bordeaux, France
| | - Patrice André
- Laboratoire de Virologie, Centre de Biologie Nord, Hôpital de la Croix Rousse, Lyon, France
| | | | | | - Sylvie Larrat
- Laboratoire de Virologie, UMI 3265 UJF-EMBL-CNRS, CHU, Unit of Virus Host Cell Interactions, Grenoble, France
| | - Anne Signori-Schmuck
- Laboratoire de Virologie, UMI 3265 UJF-EMBL-CNRS, CHU, Unit of Virus Host Cell Interactions, Grenoble, France
| | - Hénia Saoudin
- Laboratoire de Bactériologie-Virologie, CHU Saint-Etienne, France
| | - Bruno Pozzetto
- Laboratoire de Bactériologie-Virologie, CHU Saint-Etienne, France
| | | | | | | | | | - Jacques Izopet
- Laboratoire de Virologie, CNR VHE, Inserm U1043, CHU Purpan, Toulouse, France
| | - Christopher Payan
- Département de Bactériologie-Virologie-Hygiène Hospitalière et Parasitologie-Mycologie, CHRU, LUBEM, Brest, France
| | - Françoise Lunel-Fabiani
- Laboratoire de Virologie, CHU Angers, France
- HIFIH Laboratory, UPRES 3859, SFR 4208, LUNAM University, Angers, France
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Jackson PE, Tebit DM, Rekosh D, Hammarskjold ML. Rev-RRE Functional Activity Differs Substantially Among Primary HIV-1 Isolates. AIDS Res Hum Retroviruses 2016; 32:923-34. [PMID: 27147495 DOI: 10.1089/aid.2016.0047] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The HIV-1 replication cycle requires the nucleocytoplasmic export of intron-containing viral RNAs, a process that is ordinarily restricted. HIV overcomes this by means of the viral Rev protein, which binds to an RNA secondary structure called the Rev response element (RRE) present in all unspliced or incompletely spliced viral RNA transcripts. The resulting mRNP complex is exported through interaction with cellular factors. The Rev-RRE binding interaction is increasingly understood to display remarkable structural plasticity, but little is known about how Rev-RRE sequence differences affect functional activity. To study this issue, we utilized a lentiviral vector assay in which vector titer is dependent on the activity of selected Rev-RRE pairs. We found that Rev-RRE functional activity varies significantly (up to 24-fold) between naturally occurring viral isolates. The activity differences of the Rev-RRE cognate pairs track closely with Rev, but not with RRE activity. This variation in Rev activity is not correlated with differences in Rev steady state protein levels. These data suggest that Rev sequence differences drive substantial variation in Rev-RRE functional activity between patients. Such variation may play a role in viral adaptation to different immune milieus within and between patients and may be significant in the establishment of latency. The identification of differences in Rev-RRE functional activity in naturally occurring isolates may also permit more efficient production of lentiviral vectors.
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Affiliation(s)
- Patrick E. Jackson
- Department of Microbiology, Immunology, and Cancer Biology, Myles H. Thaler Center for AIDS and Human Retrovirus Research, University of Virginia, Charlottesville, Virginia
| | - Denis M. Tebit
- Department of Microbiology, Immunology, and Cancer Biology, Myles H. Thaler Center for AIDS and Human Retrovirus Research, University of Virginia, Charlottesville, Virginia
| | - David Rekosh
- Department of Microbiology, Immunology, and Cancer Biology, Myles H. Thaler Center for AIDS and Human Retrovirus Research, University of Virginia, Charlottesville, Virginia
| | - Marie-Louise Hammarskjold
- Department of Microbiology, Immunology, and Cancer Biology, Myles H. Thaler Center for AIDS and Human Retrovirus Research, University of Virginia, Charlottesville, Virginia
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Mann JK, Omarjee S, Khumalo P, Ndung'u T. Genetic determinants of Nef-mediated CD4 and HLA class I down-regulation differences between HIV-1 subtypes B and C. Virol J 2015; 12:200. [PMID: 26607225 PMCID: PMC4660847 DOI: 10.1186/s12985-015-0429-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 11/16/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND HIV-1 subtype C Nef sequences have a significantly lower ability overall to down-regulate CD4 and HLA-I than subtype B Nef sequences. Here we investigated whether Nef amino acids differing in frequency between HIV-1 subtypes B and C explain lower CD4 and HLA-I down-regulation ability of subtype C. FINDINGS Subtype-specific mutations were introduced into representative subtype B and C Nef sequences and the CD4 and HLA-I down-regulation ability of these mutants was measured by flow cytometry in a CD4+ T cell line. Subtype C consensus 20I and subtype B consensus 20M reduced and increased HLA-I down-regulation respectively, and the S88G immune escape mutation (which is significantly more frequent in subtype C than subtype B) reduced CD4 and HLA-I down-regulation. CONCLUSIONS Our data suggest that these subtype-specific differences may partly contribute to inter-subtype functional differences, and identification of an immune escape mutation - S88G - that impairs Nef function is of relevance to vaccine design.
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Affiliation(s)
- Jaclyn K Mann
- HIV Pathogenesis Programme, University of KwaZulu-Natal, 719 Umbilo Road, Durban, 4013, South Africa. .,KwaZulu-Natal Research Institute for Tuberculosis and HIV, University of KwaZulu-Natal, Durban, 4001, South Africa.
| | - Saleha Omarjee
- HIV Pathogenesis Programme, University of KwaZulu-Natal, 719 Umbilo Road, Durban, 4013, South Africa. .,KwaZulu-Natal Research Institute for Tuberculosis and HIV, University of KwaZulu-Natal, Durban, 4001, South Africa.
| | - Phumzile Khumalo
- HIV Pathogenesis Programme, University of KwaZulu-Natal, 719 Umbilo Road, Durban, 4013, South Africa. .,KwaZulu-Natal Research Institute for Tuberculosis and HIV, University of KwaZulu-Natal, Durban, 4001, South Africa.
| | - Thumbi Ndung'u
- HIV Pathogenesis Programme, University of KwaZulu-Natal, 719 Umbilo Road, Durban, 4013, South Africa. .,KwaZulu-Natal Research Institute for Tuberculosis and HIV, University of KwaZulu-Natal, Durban, 4001, South Africa. .,Ragon Institute of MGH, MIT and Harvard University, Cambridge, MA, 02139, USA. .,Max Planck Institute for Infection Biology, Chariteplatz, D-10117, Berlin, Germany.
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4
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A unique evolution of the s2 gene of equine infectious anemia virus in hosts correlated with particular infection statuses. Viruses 2014; 6:4265-79. [PMID: 25390683 PMCID: PMC4246221 DOI: 10.3390/v6114265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 10/26/2014] [Accepted: 10/29/2014] [Indexed: 11/17/2022] Open
Abstract
Equine infectious anemia virus (EIAV) is a member of the Lentivirus genus in the Retroviridae family that exhibits a genomic structure similar to that of HIV-1. The S2 accessory proteins play important roles in viral replication in vivo and in viral pathogenicity; however, studies on S2 evolution in vivo are limited. This study analyzed the evolutionary characteristics of the S2 gene of a pathogenic EIAV strain, EIAVLN40, in four experimentally infected horses. The results demonstrated that 14.7% (10 of 68 residues) of the stable amino acid mutations occurred longitudinally in S2 during a 150-day infection period. Further analysis revealed that six of the ten mutated residues were positively selected during the infection. Alignment and phylogenetic analyses showed that the S2 gene sequences of viruses isolated from the infected horses at the early stage of EIAVLN40 infection were highly homologous and similar to the vaccine-specific sequence. The S2 gene variants isolated from the febrile episodes and late phase of infection became homologous to the S2 gene sequence of the inoculating EIAVLN40 strain. Our results indicate that the S2 gene evolves in diversity and divergence in vivo in different stages of EIAV infection and that this evolution correlates with the pathogenicity of the virus.
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Adland E, Carlson JM, Paioni P, Kløverpris H, Shapiro R, Ogwu A, Riddell L, Luzzi G, Chen F, Balachandran T, Heckerman D, Stryhn A, Edwards A, Ndung’u T, Walker BD, Buus S, Goulder P, Matthews PC. Nef-specific CD8+ T cell responses contribute to HIV-1 immune control. PLoS One 2013; 8:e73117. [PMID: 24023819 PMCID: PMC3759414 DOI: 10.1371/journal.pone.0073117] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 07/24/2013] [Indexed: 12/29/2022] Open
Abstract
Recent studies in the SIV-macaque model of HIV infection suggest that Nef-specific CD8+ T-cell responses may mediate highly effective immune control of viraemia. In HIV infection Nef recognition dominates in acute infection, but in large cohort studies of chronically infected subjects, breadth of T cell responses to Nef has not been correlated with significant viraemic control. Improved disease outcomes have instead been associated with targeting Gag and, in some cases, Pol. However analyses of the breadth of Nef-specific T cell responses have been confounded by the extreme immunogenicity and multiple epitope overlap within the central regions of Nef, making discrimination of distinct responses impossible via IFN-gamma ELISPOT assays. Thus an alternative approach to assess Nef as an immune target is needed. Here, we show in a cohort of >700 individuals with chronic C-clade infection that >50% of HLA-B-selected polymorphisms within Nef are associated with a predicted fitness cost to the virus, and that HLA-B alleles that successfully drive selection within Nef are those linked with lower viral loads. Furthermore, the specific CD8+ T cell epitopes that are restricted by protective HLA Class I alleles correspond substantially to effective SIV-specific epitopes in Nef. Distinguishing such individual HIV-specific responses within Nef requires specific peptide-MHC I tetramers. Overall, these data suggest that CD8+ T cell targeting of certain specific Nef epitopes contributes to HIV suppression. These data suggest that a re-evaluation of the potential use of Nef in HIV T-cell vaccine candidates would be justified.
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Affiliation(s)
- Emily Adland
- Department of Paediatrics, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
- * E-mail:
| | - Jonathan M. Carlson
- Microsoft Research, eScience Group, Los Angeles, California, United States of America
| | - Paolo Paioni
- Department of Paediatrics, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
| | - Henrik Kløverpris
- Department of Paediatrics, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
- Laboratory of Experimental Immunology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
- KwaZulu-Natal Research Institute for Tuberculosis & HIV, K-RITH, Nelson R Mandela School of Medicine, University of KwaZuluNatal, Durban, South Africa
| | - Roger Shapiro
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
- Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana
| | - Anthony Ogwu
- Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana
| | - Lynn Riddell
- Department of Genitourinary Medicine, Northamptonshire Healthcare NHS Trust,Northampton General Hospital, Northampton, United Kingdom
| | - Graz Luzzi
- Department of Genitourinary Medicine, Wycombe Hospital, High Wycombe, Bucks, United Kingdom
| | - Fabian Chen
- Department of Sexual Health, Royal Berkshire Hospital, Reading, United Kingdom
| | - Thambiah Balachandran
- Department of Genitourinary Medicine, Luton and Dunstable Hospital, Luton, United Kingdom
| | - David Heckerman
- Microsoft Research, eScience Group, Los Angeles, California, United States of America
| | - Anette Stryhn
- Laboratory of Experimental Immunology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anne Edwards
- The Oxford Department of Genitourinary Medicine, the Churchill Hospital, Oxford, United Kingdom
| | - Thumbi Ndung’u
- HIV Pathogenesis Programme, the Doris Duke Medical Research Institute, University of KwaZuluNatal, Durban, South Africa
- Ragon Institute of Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
| | - Bruce D. Walker
- HIV Pathogenesis Programme, the Doris Duke Medical Research Institute, University of KwaZuluNatal, Durban, South Africa
- Ragon Institute of Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
| | - Søren Buus
- Laboratory of Experimental Immunology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Philip Goulder
- Department of Paediatrics, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
- HIV Pathogenesis Programme, the Doris Duke Medical Research Institute, University of KwaZuluNatal, Durban, South Africa
- Ragon Institute of Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Philippa C. Matthews
- Nuffield Department of Medicine, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
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Bizinoto MC, Yabe S, Leal É, Kishino H, Martins LDO, de Lima ML, Morais ER, Diaz RS, Janini LM. Codon pairs of the HIV-1 vif gene correlate with CD4+ T cell count. BMC Infect Dis 2013; 13:173. [PMID: 23578255 PMCID: PMC3637627 DOI: 10.1186/1471-2334-13-173] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 03/26/2013] [Indexed: 01/28/2023] Open
Abstract
Background The human APOBEC3G (A3G) protein activity is associated with innate immunity against HIV-1 by inducing high rates of guanosines to adenosines (G-to-A) mutations (viz., hypermutation) in the viral DNA. If hypermutation is not enough to disrupt the reading frames of viral genes, it may likely increase the HIV-1 diversity. To counteract host innate immunity HIV-1 encodes the Vif protein that binds A3G protein and form complexes to be degraded by cellular proteolysis. Methods Here we studied the pattern of substitutions in the vif gene and its association with clinical status of HIV-1 infected individuals. To perform the study, unique vif gene sequences were generated from 400 antiretroviral-naïve individuals. Results The codon pairs: 78–154, 85–154, 101–157, 105–157, and 105–176 of vif gene were associated with CD4+ T cell count lower than 500 cells per mm3. Some of these codons were located in the 81LGQGVSIEW89 region and within the BC-Box. We also identified codons under positive selection clustered in the N-terminal region of Vif protein, between 21WKSLVK26 and 40YRHHY44 regions (i.e., 31, 33, 37, 39), within the BC-Box (i.e., 155, 159) and the Cullin5-Box (i.e., 168) of vif gene. All these regions are involved in the Vif-induced degradation of A3G/F complexes and the N-terminal of Vif protein binds to viral and cellular RNA. Conclusions Adaptive evolution of vif gene was mostly to optimize viral RNA binding and A3G/F recognition. Additionally, since there is not a fully resolved structure of the Vif protein, codon pairs associated with CD4+ T cell count may elucidate key regions that interact with host cell factors. Here we identified and discriminated codons under positive selection and codons under functional constraint in the vif gene of HIV-1.
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Corró G, Rocco CA, De Candia C, Catano G, Turk G, Mangano A, Aulicino PC, Bologna R, Sen L. Genetic and functional analysis of HIV type 1 nef gene derived from long-term nonprogressor children: association of attenuated variants with slow progression to pediatric AIDS. AIDS Res Hum Retroviruses 2012; 28:1617-26. [PMID: 22583022 DOI: 10.1089/aid.2012.0020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Among persons infected by HIV-1, the rate of progression to AIDS is multifactorial being affected by host and viral factors, including the HIV-encoded negative factor (Nef). Our aim was to define whether variations in the nef gene as well as its functions may be associated with slower HIV disease course in infected children. The proviral HIV-1 nef gene was cloned, sequenced, and compared in children with contrasting disease course: 10 long-term nonprogressors (LTNP) and six rapid progressor (RP). The CD4 and MHC-I down-modulation ability of nef alleles derived from LTNP and RP children was analyzed. We observed that only one of our 10 LTNP had a protective genetic background, and out of them, 40% had defective nef genes, carrying substitutions at the (AWLEAQ(56-61)) and the (Rxx(22-24)) domains, and that those alleles were unable of down-regulate CD4 and MHC-I. The emergence or presence of Nef L58V substitution was associated with viral attenuation, indicated by a reduction in HIV viral loads, a persistent preservation of CD4(+) T cell counts, and lack of AIDS-related symptoms. Our results demonstrate that HIV-1 perinatally infected children carrying functionally defective nef HIV-1 strains have prolonged asymptomatic phases without therapy, suggesting a relevant role of CD4 and MHC-I down-modulation Nef domains on in vivo HIV-1 pathogenesis and pediatric immunodeficiency outcome.
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Affiliation(s)
- Guillermo Corró
- Laboratorio de Biología Celular y Retrovirus, Hospital de Pediatría “Prof. Dr. Juan P. Garran,” Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnológicas, Buenos Aires, Argentina
| | - Carlos A Rocco
- Laboratorio de Biología Celular y Retrovirus, Hospital de Pediatría “Prof. Dr. Juan P. Garran,” Buenos Aires, Argentina
| | - Cristian De Candia
- National Reference Center for AIDS, University of Buenos Aires, Buenos Aires, Argentina
| | - Gabriel Catano
- Veterans Administration Research Center for AIDS and HIV-1 Infection, South Texas Veterans Health Care System and Department of Medicine, University of Texas Health Science Care at San Antonio, San Antonio, Texas
| | - Gabriela Turk
- National Reference Center for AIDS, University of Buenos Aires, Buenos Aires, Argentina
| | - Andrea Mangano
- Laboratorio de Biología Celular y Retrovirus, Hospital de Pediatría “Prof. Dr. Juan P. Garran,” Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnológicas, Buenos Aires, Argentina
| | - Paula C. Aulicino
- Laboratorio de Biología Celular y Retrovirus, Hospital de Pediatría “Prof. Dr. Juan P. Garran,” Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnológicas, Buenos Aires, Argentina
| | - Rosa Bologna
- Servicio de Infectología, Hospital de Pediatría “Prof. Dr. Juan P. Garrahan,” Buenos Aires, Argentina
| | - Luisa Sen
- Laboratorio de Biología Celular y Retrovirus, Hospital de Pediatría “Prof. Dr. Juan P. Garran,” Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnológicas, Buenos Aires, Argentina
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Immune selection in vitro reveals human immunodeficiency virus type 1 Nef sequence motifs important for its immune evasion function in vivo. J Virol 2012; 86:7126-35. [PMID: 22553319 DOI: 10.1128/jvi.00878-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) Nef downregulates major histocompatibility complex class I (MHC-I), impairing the clearance of infected cells by CD8(+) cytotoxic T lymphocytes (CTLs). While sequence motifs mediating this function have been determined by in vitro mutagenesis studies of laboratory-adapted HIV-1 molecular clones, it is unclear whether the highly variable Nef sequences of primary isolates in vivo rely on the same sequence motifs. To address this issue, nef quasispecies from nine chronically HIV-1-infected persons were examined for sequence evolution and altered MHC-I downregulatory function under Gag-specific CTL immune pressure in vitro. This selection resulted in decreased nef diversity and strong purifying selection. Site-by-site analysis identified 13 codons undergoing purifying selection and 1 undergoing positive selection. Of the former, only 6 have been reported to have roles in Nef function, including 4 associated with MHC-I downregulation. Functional testing of naturally occurring in vivo polymorphisms at the 7 sites with no previously known functional role revealed 3 mutations (A84D, Y135F, and G140R) that ablated MHC-I downregulation and 3 (N52A, S169I, and V180E) that partially impaired MHC-I downregulation. Globally, the CTL pressure in vitro selected functional Nef from the in vivo quasispecies mixtures that predominately lacked MHC-I downregulatory function at the baseline. Overall, these data demonstrate that CTL pressure exerts a strong purifying selective pressure for MHC-I downregulation and identifies novel functional motifs present in Nef sequences in vivo.
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Zuo J, Suen J, Wong A, Lewis M, Ayub A, Belzer M, Church J, Yang OO, Krogstad P. Functional analysis of HIV type 1 Nef gene variants from adolescent and adult survivors of perinatal infection. AIDS Res Hum Retroviruses 2012; 28:486-92. [PMID: 21861776 DOI: 10.1089/aid.2011.0172] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Throughout the world, infants and children with HIV-1 infection are increasingly surviving into adolescence and adulthood. As HIV Nef is an important determinant of the pathogenic potential of the virus, we examined nef alleles in a cohort of extreme long-term survivors of HIV infection (average age of 16.6 years) to determine if Nef defects might have contributed to patient survival. HIV nef gene sequences were amplified for phylogenetic analysis from 15 adolescents and adults infected by mother-to-child transmission (n=10) or by blood transfusion (n=5). Functional analysis was performed by inserting patient-derived nef sequences into an HIV-derived vector that permits simultaneous evaluation of the impact of the Nef protein on MHC-I and CD4 cell surface expression. We found evidence of extensive nef gene diversity, including changes in known functional domains involved in the downregulation of cell surface MHC-I and CD4. Only 3 of 15 individuals (20%) had nef alleles with a loss of the ability to downregulate either CD4 or MHC-I. Survival into adulthood with HIV infection acquired in infancy is not uniformly linked to loss of function in nef. The Nef protein remains a potential target for immunization or pharmacologic intervention.
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Affiliation(s)
- Jun Zuo
- UCLA AIDS Institute and the David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Jeffrey Suen
- UCLA AIDS Institute and the David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Alanna Wong
- UCLA AIDS Institute and the David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Martha Lewis
- UCLA AIDS Institute and the David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Ali Ayub
- UCLA AIDS Institute and the David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Marvin Belzer
- Childrens Hospital Los Angeles and the Keck School of Medicine at USC, Los Angeles, California
| | - Joseph Church
- Childrens Hospital Los Angeles and the Keck School of Medicine at USC, Los Angeles, California
| | - Otto O. Yang
- UCLA AIDS Institute and the David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Paul Krogstad
- UCLA AIDS Institute and the David Geffen School of Medicine at UCLA, Los Angeles, California
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Tebit DM, Arts EJ. Tracking a century of global expansion and evolution of HIV to drive understanding and to combat disease. THE LANCET. INFECTIOUS DISEASES 2011; 11:45-56. [PMID: 21126914 DOI: 10.1016/s1473-3099(10)70186-9] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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11
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High viremia is associated with high levels of in vivo major histocompatibility complex class I Downregulation in rhesus macaques infected with simian immunodeficiency virus SIVmac239. J Virol 2010; 84:5443-7. [PMID: 20219903 DOI: 10.1128/jvi.02452-09] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human and simian immunodeficiency viruses (HIV and SIV) downregulate major histocompatibility complex class I (MHC-I) molecules from the surface of infected cells. Although this activity is conserved across viral isolates, its importance in AIDS pathogenesis is not clear. We therefore developed an assay to detect the level of MHC-I expression of SIV-infected cells directly ex vivo. Here we show that the extent of MHC-I downregulation is greatest in SIVmac239-infected macaques that never effectively control virus replication. Our results suggest that a high level of MHC-I downregulation is a hallmark of fast disease progression in SIV infection.
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Replicative capacity of human immunodeficiency virus type 1 transmitted from mother to child is associated with pediatric disease progression rate. J Virol 2010; 84:492-502. [PMID: 19828603 DOI: 10.1128/jvi.01743-09] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus (HIV)-infected infants in the developing world typically progress to AIDS or death within the first 2 years of life. However, a minority progress relatively slowly. This study addresses the potential contribution of viral factors to HIV disease progression in eight infants selected from a well-characterized cohort of C clade HIV-infected infants, monitored prospectively from birth in Durban, South Africa. Three infants were defined as "progressors," and five were defined as "slow progressors." We observed that slow-progressor infants carry HIV isolates with significantly lower replicative capacity compared to virus from progressors. Furthermore, our data suggest a link between the attenuated viral phenotype and HLA-B* 57/5801 epitope-specific Gag mutational patterns of the transmitted virus and not to coreceptor usage or to the presence of Nef deletions or insertions. These data underline the importance of virus-host interactions and highlight the contribution of viral attenuation through Gag-specific CD8(+) T-cell escape mutations, among other factors, in the control of pediatric HIV infection.
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Campbell GR, Loret EP, Spector SA. HIV-1 clade B Tat, but not clade C Tat, increases X4 HIV-1 entry into resting but not activated CD4+ T cells. J Biol Chem 2010; 285:1681-91. [PMID: 19917610 PMCID: PMC2804326 DOI: 10.1074/jbc.m109.049957] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 11/13/2009] [Indexed: 11/06/2022] Open
Abstract
CXCR4-using human immunodeficiency virus, type 1 (HIV-1) variants emerge late in the course of infection in >40% of individuals infected with clade B HIV-1 but are described less commonly with clade C isolates. Tat is secreted by HIV-1-infected cells where it acts on both uninfected bystander cells and infected cells. In this study, we show that clade B Tat, but not clade C Tat, increases CXCR4 surface expression on resting CD4+ T cells through a CCR2b-dependent mechanism that does not involve de novo protein synthesis. The expression of plectin, a cytolinker protein that plays an important role as a scaffolding platform for proteins involved in cellular signaling including CXCR4 signaling and trafficking, was found to be significantly increased following B Tat but not C Tat treatment. Knockdown of plectin using RNA interference showed that plectin is essential for the B Tat-induced translocation of CXCR4 to the surface of resting CD4+ T cells. The increased surface CXCR4 expression following B Tat treatment led to increased function of CXCR4 including increased chemoattraction toward CXCR4-using-gp120. Moreover, increased CXCR4 surface expression rendered resting CD4+ T cells more permissive to X4 but not R5 HIV-1 infection. However, neither B Tat nor C Tat was able to up-regulate surface expression of CXCR4 on activated CD4+ T cells, and both proteins inhibited the infection of activated CD4+ T cells with X4 but not R5 HIV-1. Thus, B Tat, but not C Tat, has the capacity to render resting, but not activated, CD4+ T cells more susceptible to X4 HIV-1 infection.
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Affiliation(s)
- Grant R. Campbell
- From the Department of Pediatrics, Division of Infectious Diseases, University of California San Diego, La Jolla, California 92093-0672
| | - Erwann P. Loret
- INSERM U911, Faculté de Pharmacie, Université de la Méditerranée, 13385 Marseille Cedex 5, France
| | - Stephen A. Spector
- From the Department of Pediatrics, Division of Infectious Diseases, University of California San Diego, La Jolla, California 92093-0672
- Rady Children's Hospital, San Diego, California 92123, and
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Tzitzivacos D, Tiemessen C, Stevens W, Papathanasopoulos M. Viral genetic determinants of nonprogressive HIV type 1 subtype C infection in antiretroviral drug-naive children. AIDS Res Hum Retroviruses 2009; 25:1141-8. [PMID: 19895210 DOI: 10.1089/aid.2009.0080] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Characterization of HIV-1 from slow progressors is important to facilitate vaccine and antiviral drug development. To identify virus attenuations that may contribute to slower rates of disease progression, the full-length viral genomes from primary isolates of six slow progressing HIV-positive children were sequenced. Proviral DNA was extracted from cocultured peripheral blood mononuclear cells and used to PCR amplify, sequence, and extensively analyze the near full-length genomes and LTR regions. All primary HIV-1 isolates were HIV-1 subtype C throughout their genome, and amino acid (AA) sequence analysis revealed open reading frames for all genes. However, all isolates had at least one unusual gene/protein. For example, isolate LT5 had a 2AA insertion in the Vpr mitochondriotoxic domain. Isolate LT21 contained an additional 5AA in the C-terminus of tat exon 2, while integrase in isolate LT39 had an additional 4AA at the C-terminus. Rev from isolates LT45 and LT46 did not have the characteristic subtype C 16AA truncation, and in addition, had a further 3AA. Furthermore, altered functional domains were noted in several isolates, such as the cAMP-dependent kinase PKA phosphorylation site in Nef (LT5), a Vpr mutation involved in decreased proapoptotic activity (all isolates), and the Nef ExxxLL motif involved in the interaction with AP-1 and AP-2 (LT46). The slower HIV-1 disease progression in these six children may be attributed to altered protein functions. For example, LT46 Nef is unable to bind AP-1 and AP-2 and therefore is inactive on CD4 endocytosis. The biological relevance of these findings requires further investigation.
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Affiliation(s)
- D.B. Tzitzivacos
- HIV Pathogenesis Research Laboratory, Department of Molecular Medicine and Haematology, University of the Witwatersrand Medical School, Parktown, Johannesburg 2193, South Africa
| | - C.T. Tiemessen
- Cell Biology, AIDS Virus Research Unit, National Institute for Communicable Diseases, Johannesburg 2131, South Africa
| | - W.S. Stevens
- HIV Pathogenesis Research Laboratory, Department of Molecular Medicine and Haematology, University of the Witwatersrand Medical School, Parktown, Johannesburg 2193, South Africa
| | - M.A. Papathanasopoulos
- HIV Pathogenesis Research Laboratory, Department of Molecular Medicine and Haematology, University of the Witwatersrand Medical School, Parktown, Johannesburg 2193, South Africa
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Cavalieri E, Florido C, Leal É, Machado DM, Camargo M, Diaz RS, Janini LM. Intrahost and interhost variability of the HIV type 1 nef gene in Brazilian children. AIDS Res Hum Retroviruses 2009; 25:1129-40. [PMID: 19943790 DOI: 10.1089/aid.2009.0061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Many aspects of HIV-1 pathogenesis are affected by Nef protein activity, and efforts have been made to study variation in the nef gene and how that variation relates to disease outcome. We studied the genetic diversity of the nef gene in distinct clones obtained from the same patient (intrahost) and in sequences obtained from different hosts (interhost). The set of sequences analyzed was obtained from HIV-1-infected Brazilian children and contained 112 clones from 25 children (intrahost samples), as well as 55 sequences from epidemiologically unlinked children (interhost samples). We found extensive site polymorphisms and amino acid length variations, mainly in the amino terminal region of the nef gene, between the myristoylation motif (MGxxxS) and the MHC-1 downregulation motif (Rxx). Analysis of the sequences deposited in the Los Alamos HIV sequences database ( www.hiv.lanl.gov ) indicated that the most frequent motif at the MHC-1 downregulation site in the subtype B strain is R(86%)A(64%)E(82%) (n = 1040) and R(78%)T(74%)E(56%) in the subtype C strain (n = 549). Conversely, the Brazilian subtype B isolates presented the motif R(81%)T(62%)E(67%) at this site (n = 64). A detailed analysis of selective pressures identified a concentration of codons under strong positive selection in the amino terminal region of the nef gene. We also determined that different sites are under positive selection in the subtype B and subtype C viruses. The amino acid composition in the MHC-1 downregulation motif of the nef gene in our sequences may indicate a distinct adaptive pattern of HIV-1 subtype B to the Brazilian host population.
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Affiliation(s)
| | | | - Élcio Leal
- Federal University of São Paulo, São Paulo, Brazil
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Campbell GR, Loret EP. What does the structure-function relationship of the HIV-1 Tat protein teach us about developing an AIDS vaccine? Retrovirology 2009; 6:50. [PMID: 19467159 PMCID: PMC2693501 DOI: 10.1186/1742-4690-6-50] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Accepted: 05/25/2009] [Indexed: 11/03/2022] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) trans-activator of transcription protein Tat is an important factor in viral pathogenesis. In addition to its function as the key trans-activator of viral transcription, Tat is also secreted by the infected cell and taken up by neighboring cells where it has an effect both on infected and uninfected cells. In this review we will focus on the relationship between the structure of the Tat protein and its function as a secreted factor. To this end we will summarize some of the exogenous functions of Tat that have been implicated in HIV-1 pathogenesis and the impact of structural variations and viral subtype variants of Tat on those functions. Finally, since in some patients the presence of Tat-specific antibodies or CTL frequencies are associated with slow or non-progression to AIDS, we will also discuss the role of Tat as a potential vaccine candidate, the advances made in this field, and the importance of using a Tat protein capable of eliciting a protective or therapeutic immune response to viral challenge.
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Affiliation(s)
- Grant R Campbell
- Department of Pediatrics, Division of Infectious Diseases, University of California San Diego, La Jolla, California 92093-0672, USA.
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Predicting the impact of blocking human immunodeficiency virus type 1 Nef in vivo. J Virol 2008; 83:2349-56. [PMID: 19091857 DOI: 10.1128/jvi.00821-08] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) Nef is a multifunctional protein that confers an ability to evade killing by cytotoxic T lymphocytes (CTLs) as well as other advantages to the virus in vivo. Here we exploited mathematical modeling and related statistical methods to estimate the impact of Nef activity on viral replication in vivo in relation to CTLs. Our results indicate that downregulation of major histocompatibility complex class I (MHC-I) A and B by wild-type Nef confers an advantage to the virus of about 82% in decreased CTL killing efficiency on average, meaning that abolishing the MHC-I downregulation function of Nef would increase killing by more than fivefold. We incorporated this estimate, as well as prior estimates of replicative enhancement by Nef, into a previously published model of HIV-1 and CTLs in vivo (W. D. Wick, O. O. Yang, L. Corey, and S. G. Self, J. Virol. 79:13579-13586, 2005), generalized to permit CTL recognition of multiple epitopes. A sequence database analysis revealed that 92.9% of HIV-1 epitopes are A or B restricted, and a previous study found an average of about 19 epitopes recognized (M. M. Addo et al., J. Virol. 77:2081-2092, 2003). We combined these estimates in the model in order to predict the impact of inhibiting Nef function in the general (chronically infected) population by a drug. The predicted impact on viral load ranged from negligible to 2.4 orders of magnitude, depending on the effects of the drug and the CTL dynamical scenario assumed. We conclude that inhibiting Nef could make a substantial reduction in disease burden, lengthening the time before the necessity of undertaking combination therapy with other antiretroviral drugs.
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Lewis MJ, Balamurugan A, Ohno A, Kilpatrick S, Ng HL, Yang OO. Functional adaptation of Nef to the immune milieu of HIV-1 infection in vivo. THE JOURNAL OF IMMUNOLOGY 2008; 180:4075-81. [PMID: 18322217 DOI: 10.4049/jimmunol.180.6.4075] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Nef-mediated down-regulation of MHC class I (MHC-I) molecules on HIV-1-infected cells has been proposed to enhance viral persistence through evasion of host CTLs. This conclusion is based largely on demonstrations that Nef from laboratory HIV-1 strains reduces the susceptibility of infected cells to CTL killing in vitro. However, the function and role of Nef-mediated MHC-I down-regulation in vivo have not been well described. To approach this issue, nef quasispecies from chronically HIV-1-infected individuals were cloned into recombinant reporter viruses and tested for their ability to down-regulate MHC-I molecules from the surface of infected cells. The level of function varied widely between individuals, and although comparison to the immunologic parameters of blood CD4(+) T lymphocyte count and breadth of the HIV-1-specific CTL response showed positive correlations, no significant correlation was found in comparison to plasma viremia. The ability of in vivo-derived Nef to down-regulate MHC-I predicted the resistance of HIV-1 to suppression by CTL. Taken together, these data demonstrate the functionality of Nef to down-regulate MHC-I in vivo during stable chronic infection, and suggest that this function is maintained by the need of HIV-1 to cope with the antiviral CTL response.
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Affiliation(s)
- Martha J Lewis
- Geffen School of Medicine, University of California, Department of Medicine, Division of Infectious Diseases, Los Angeles, CA 90095, USA.
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Disease progression and evolution of the HIV-1 env gene in 24 infected infants. INFECTION GENETICS AND EVOLUTION 2008; 8:110-20. [DOI: 10.1016/j.meegid.2007.10.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 10/23/2007] [Accepted: 10/24/2007] [Indexed: 11/23/2022]
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Compartmentalization of the gut viral reservoir in HIV-1 infected patients. Retrovirology 2007; 4:87. [PMID: 18053211 PMCID: PMC2217557 DOI: 10.1186/1742-4690-4-87] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Accepted: 12/04/2007] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Recently there has been an increasing interest and appreciation for the gut as both a viral reservoir as well as an important host-pathogen interface in human immunodefiency virus type 1 (HIV-1) infection. The gut associated lymphoid tissue (GALT) is the largest lymphoid organ infected by HIV-1. In this study we examined if different HIV-1 quasispecies are found in different parts of the gut of HIV-1 infected individuals. RESULTS Gut biopsies (esophagus, stomach, duodenum and colorectum) were obtained from eight HIV-1 infected preHAART (highly active antiretroviral therapy) patients. HIV-1 Nef and Reverse transcriptase (RT) encoding sequences were obtained through nested PCR amplification from DNA isolated from the gut biopsy tissues. The PCR fragments were cloned and sequenced. The resulting sequences were subjected to various phylogenetic analyses. Expression of the nef gene and viral RNA in the different gut tissues was determined using real-time RT-PCR. Phylogenetic analysis of the Nef protein-encoding region revealed compartmentalization of viral replication in the gut within patients. Viral diversity in both the Nef and RT encoding region varied in different parts of the gut. Moreover, increased nef gene expression (p < 0.05) and higher levels of viral genome were observed in the colorectum (p < 0.05). These differences could reflect an adaptation of HIV-1 to the various tissues. CONCLUSION Our results indicated that different HIV-1 quasispecies populate different parts of the gut, and that viral replication in the gut is compartmentalized. These observations underscore the importance of the gut as a host-pathogen interface in HIV-1 infection.
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