1
|
Rosichini M, Bordoni V, Silvestris DA, Mariotti D, Matusali G, Cardinale A, Zambruno G, Condorelli AG, Flamini S, Genah S, Catanoso M, Del Nonno F, Trezzi M, Galletti L, De Stefanis C, Cicolani N, Petrini S, Quintarelli C, Agrati C, Locatelli F, Velardi E. SARS-CoV-2 infection of thymus induces loss of function that correlates with disease severity. J Allergy Clin Immunol 2023; 151:911-921. [PMID: 36758836 PMCID: PMC9907790 DOI: 10.1016/j.jaci.2023.01.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 12/14/2022] [Accepted: 01/19/2023] [Indexed: 02/11/2023]
Abstract
BACKGROUND Lymphopenia, particularly when restricted to the T-cell compartment, has been described as one of the major clinical hallmarks in patients with coronavirus disease 2019 (COVID-19) and proposed as an indicator of disease severity. Although several mechanisms fostering COVID-19-related lymphopenia have been described, including cell apoptosis and tissue homing, the underlying causes of the decline in T-cell count and function are still not completely understood. OBJECTIVE Given that viral infections can directly target thymic microenvironment and impair the process of T-cell generation, we sought to investigate the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on thymic function. METHODS We performed molecular quantification of T-cell receptor excision circles and κ-deleting recombination excision circles to assess, respectively, T- and B-cell neogenesis in SARS-CoV-2-infected patients. We developed a system for in vitro culture of primary human thymic epithelial cells (TECs) to mechanistically investigate the impact of SARS-CoV-2 on TEC function. RESULTS We showed that patients with COVID-19 had reduced thymic function that was inversely associated with the severity of the disease. We found that angiotensin-converting enzyme 2, through which SARS-CoV-2 enters the host cells, was expressed by thymic epithelium, and in particular by medullary TECs. We also demonstrated that SARS-CoV-2 can target TECs and downregulate critical genes and pathways associated with epithelial cell adhesion and survival. CONCLUSIONS Our data demonstrate that the human thymus is a target of SARS-CoV-2 and thymic function is altered following infection. These findings expand our current knowledge of the effects of SARS-CoV-2 infection on T-cell homeostasis and suggest that monitoring thymic activity may be a useful marker to predict disease severity and progression.
Collapse
Affiliation(s)
- Marco Rosichini
- Department of Pediatric Hematology and Oncology, Cell and Gene Therapy, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy,Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Veronica Bordoni
- Department of Pediatric Hematology and Oncology, Cell and Gene Therapy, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy,Cellular Immunology Laboratory, INMI L Spallanzani – IRCCS, Rome, Italy
| | - Domenico Alessandro Silvestris
- Department of Pediatric Hematology and Oncology, Cell and Gene Therapy, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Davide Mariotti
- Cellular Immunology Laboratory, INMI L Spallanzani – IRCCS, Rome, Italy
| | - Giulia Matusali
- Virology Laboratory, INMI L Spallanzani – IRCCS, Rome, Italy
| | - Antonella Cardinale
- Department of Pediatric Hematology and Oncology, Cell and Gene Therapy, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Giovanna Zambruno
- Genodermatosis Unit, Genetics and Rare Diseases Research Division, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Angelo Giuseppe Condorelli
- Genodermatosis Unit, Genetics and Rare Diseases Research Division, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Sara Flamini
- Department of Pediatric Hematology and Oncology, Cell and Gene Therapy, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Shirley Genah
- Department of Pediatric Hematology and Oncology, Cell and Gene Therapy, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Marialuigia Catanoso
- Department of Pediatric Hematology and Oncology, Cell and Gene Therapy, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy,Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | | | - Matteo Trezzi
- Cardiac Surgery Unit, Department of Pediatric Cardiology and Cardiac Surgery, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Lorenzo Galletti
- Cardiac Surgery Unit, Department of Pediatric Cardiology and Cardiac Surgery, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Cristiano De Stefanis
- Pathology Unit, Core Research Laboratories, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Nicolò Cicolani
- Confocal Microscopy Core Facility, Research Center, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Stefania Petrini
- Confocal Microscopy Core Facility, Research Center, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Concetta Quintarelli
- Department of Pediatric Hematology and Oncology, Cell and Gene Therapy, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy,Department of Clinical Medicine and Surgery, University of Naples Federico II, Rome, Italy
| | - Chiara Agrati
- Department of Pediatric Hematology and Oncology, Cell and Gene Therapy, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy,Cellular Immunology Laboratory, INMI L Spallanzani – IRCCS, Rome, Italy
| | - Franco Locatelli
- Department of Pediatric Hematology and Oncology, Cell and Gene Therapy, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy,Catholic University of the Sacred Heart, Rome, Italy
| | - Enrico Velardi
- Department of Pediatric Hematology and Oncology, Cell and Gene Therapy, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
| |
Collapse
|
2
|
Insights into Thymus Development and Viral Thymic Infections. Viruses 2019; 11:v11090836. [PMID: 31505755 PMCID: PMC6784209 DOI: 10.3390/v11090836] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/03/2019] [Accepted: 09/06/2019] [Indexed: 12/16/2022] Open
Abstract
T-cell development in the thymus is a complex and highly regulated process, involving a wide variety of cells and molecules which orchestrate thymocyte maturation into either CD4+ or CD8+ single-positive (SP) T cells. Here, we briefly review the process regulating T-cell differentiation, which includes the latest advances in this field. In particular, we highlight how, starting from a pool of hematopoietic stem cells in the bone marrow, the sequential action of transcriptional factors and cytokines dictates the proliferation, restriction of lineage potential, T-cell antigen receptors (TCR) gene rearrangements, and selection events on the T-cell progenitors, ultimately leading to the generation of mature T cells. Moreover, this review discusses paradigmatic examples of viral infections affecting the thymus that, by inducing functional changes within this lymphoid gland, consequently influence the behavior of peripheral mature T-lymphocytes.
Collapse
|
3
|
Starikova EA, Golovin AS, Vasilyev KA, Karaseva AB, Serebriakova MK, Sokolov AV, Kudryavtsev IV, Burova LA, Voynova IV, Suvorov AN, Vasilyev VB, Freidlin IS. Role of arginine deiminase in thymic atrophy during experimental Streptococcus pyogenes infection. Scand J Immunol 2019; 89:e12734. [PMID: 30471128 DOI: 10.1111/sji.12734] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 11/11/2018] [Accepted: 11/18/2018] [Indexed: 01/08/2023]
Abstract
Expression of gene of arginine deiminase (AD) allows adaptation of Streptococcus pyogenes to adverse environmental conditions. AD activity can lead to L-arginine deficiency in the host cells' microenvironment. Bioavailability of L-arginine is an important factor regulating the functions of the immune cells in mammals. By introducing a mutation into S pyogenes M46-16, we obtained a strain with inactivated arcA/sagp gene (M49-16 delArcA), deficient in AD. This allowed elucidating the function of AD in pathogenesis of streptococcal infection. The virulence of the parental and mutant strains was examined in a murine model of subcutaneous streptococcal infection. L-arginine concentration in the plasma of mice infected with S pyogenes M49-16 delArcA remained unchanged in course of the entire experiment. At the same time mice infected with S pyogenes M49-16 demonstrated gradual diminution of L-arginine concentration in the blood plasma, which might be due to the activity of streptococcal AD. Mice infected with S pyogenes M49-16 delArcA demonstrated less intensive bacterial growth in the primary foci and less pronounced bacterial dissemination as compared with animals infected with the parental strain S pyogenes M46-16. Similarly, thymus involution, alterations in apoptosis, thymocyte subsets and Treg cells differentiation were less pronounced in mice infected with S pyogenes M49-16 delArcA than in those infected with the parental strain. The results obtained showed that S pyogenes M49-16 delArcA, unable to produce AD, had reduced virulence in comparison with the parental S pyogenes M49-16 strain. AD is an important factor for the realization of the pathogenic potential of streptococci.
Collapse
Affiliation(s)
| | | | | | - Alena Borisovna Karaseva
- Federal State Budgetary Scientific Institution, Institute of Experimental Medicine, St. Petersburg, Russia
| | | | - Alexey Victorovich Sokolov
- Federal State Budgetary Scientific Institution, Institute of Experimental Medicine, St. Petersburg, Russia.,Saint-Petersburg State University, St. Petersburg, Russia
| | - Igor Vladimirovich Kudryavtsev
- Federal State Budgetary Scientific Institution, Institute of Experimental Medicine, St. Petersburg, Russia.,Far Eastern Federal University Vladivostok, Russia
| | | | - Irina Vitalyevna Voynova
- Federal State Budgetary Scientific Institution, Institute of Experimental Medicine, St. Petersburg, Russia
| | - Alexander Nikolaevich Suvorov
- Federal State Budgetary Scientific Institution, Institute of Experimental Medicine, St. Petersburg, Russia.,Saint-Petersburg State University, St. Petersburg, Russia
| | - Vadim Borisovich Vasilyev
- Federal State Budgetary Scientific Institution, Institute of Experimental Medicine, St. Petersburg, Russia.,Saint-Petersburg State University, St. Petersburg, Russia
| | - Irina Solomonovna Freidlin
- Federal State Budgetary Scientific Institution, Institute of Experimental Medicine, St. Petersburg, Russia.,Saint-Petersburg State University, St. Petersburg, Russia.,Pavlov First Saint-Petersburg State Medical University, St. Petersburg, Russia
| |
Collapse
|
4
|
Manjati T, Nkambule B, Ipp H. Immune activation is associated with decreased thymic function in asymptomatic, untreated HIV-infected individuals. South Afr J HIV Med 2016; 17:445. [PMID: 29568606 PMCID: PMC5843076 DOI: 10.4102/sajhivmed.v17i1.445] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 05/25/2016] [Indexed: 11/15/2022] Open
Abstract
Background Reduced thymic function causes poor immunological reconstitution in human immunodeficiency virus (HIV)-positive patients on combined antiretroviral therapy (cART). The association between immune activation and thymic function in asymptomatic HIV-positive treatment-naive individuals has thus far not been investigated. Aims and objectives To optimise a five-colour flow cytometric assay for measurement of thymic function by measuring recent thymic emigrants (RTEs) in treatment-naive HIV-infected patients and healthy controls and correlate results with levels of immune activation, CD4 counts and viral load. Methods Blood obtained from 53 consenting HIV-positive individuals and 32 controls recruited from HIV prevention and testing clinic in Cape Town, South Africa. RTEs were measured (CD3+/CD4+/CD45RA+/CD31+/CD62L+) and levels were correlated with CD4 counts of HIV-infected individuals, log viral load and levels of immune activation (CD8+/CD38+ T-cells). Results HIV-infected individuals had reduced frequencies of RTEs when compared to controls (p = 0.0035). Levels of immune activation were inversely correlated with thymic function (p = 0.0403), and the thymic function in HIV-infected individuals showed no significant correlation with CD4 counts (p = 0.31559) and viral load (p = 0.20628). Conclusions There was impaired thymic function in HIV-infected individuals, which was associated with increased levels of immune activation. The thymic dysfunction was not associated with CD4 counts and viral load. Immune activation may result in inflammatory damage to the thymus and subsequent thymic dysfunction, and CD4 counts and viral load may not necessarily reflect thymic dysfunction in HIV.
Collapse
Affiliation(s)
- Thandiwe Manjati
- Division of Haematology, Department of Pathology, Stellenbosch University, South Africa.,Division of Haematopathology, National Health Laboratory Service, Tygerberg Hospital, Cape Town, South Africa
| | - Bongani Nkambule
- Division of Haematopathology, National Health Laboratory Service, Tygerberg Hospital, Cape Town, South Africa.,Department of Physiology, School of Laboratory and Medical Sciences, University of KwaZulu-Natal, South Africa
| | - Hayley Ipp
- Division of Haematology, Department of Pathology, Stellenbosch University, South Africa.,Division of Haematopathology, National Health Laboratory Service, Tygerberg Hospital, Cape Town, South Africa
| |
Collapse
|
5
|
Fiume G, Scialdone A, Albano F, Rossi A, Tuccillo FM, Rea D, Palmieri C, Caiazzo E, Cicala C, Bellevicine C, Falcone C, Vecchio E, Pisano A, Ceglia S, Mimmi S, Iaccino E, de Laurentiis A, Pontoriero M, Agosti V, Troncone G, Mignogna C, Palma G, Arra C, Mallardo M, Buonaguro FM, Scala G, Quinto I. Impairment of T cell development and acute inflammatory response in HIV-1 Tat transgenic mice. Sci Rep 2015; 5:13864. [PMID: 26343909 PMCID: PMC4561375 DOI: 10.1038/srep13864] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 08/07/2015] [Indexed: 01/22/2023] Open
Abstract
Immune activation and chronic inflammation are hallmark features of HIV infection causing T-cell depletion and cellular immune dysfunction in AIDS. Here, we addressed the issue whether HIV-1 Tat could affect T cell development and acute inflammatory response by generating a transgenic mouse expressing Tat in lymphoid tissue. Tat-Tg mice showed thymus atrophy and the maturation block from DN4 to DP thymic subpopulations, resulting in CD4+ and CD8+ T cells depletion in peripheral blood. In Tat-positive thymus, we observed the increased p65/NF-κB activity and deregulated expression of cytokines/chemokines and microRNA-181a-1, which are involved in T-lymphopoiesis. Upon LPS intraperitoneal injection, Tat-Tg mice developed an abnormal acute inflammatory response, which was characterized by enhanced lethality and production of inflammatory cytokines. Based on these findings, Tat-Tg mouse could represent an animal model for testing adjunctive therapies of HIV-1-associated inflammation and immune deregulation.
Collapse
Affiliation(s)
- Giuseppe Fiume
- Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Graecia", Viale Europa, 88100, Catanzaro, Italy
| | - Annarita Scialdone
- Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Graecia", Viale Europa, 88100, Catanzaro, Italy
| | - Francesco Albano
- Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Graecia", Viale Europa, 88100, Catanzaro, Italy
| | - Annalisa Rossi
- Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Graecia", Viale Europa, 88100, Catanzaro, Italy
| | - Franca Maria Tuccillo
- Molecular Biology and Viral Oncogenesis Unit, Department of Experimental Oncology, Istituto Nazionale Tumori "Fondazione Giovanni Pascale", IRCCS, 80131, Naples, Italy
| | - Domenica Rea
- Molecular Biology and Viral Oncogenesis Unit, Department of Experimental Oncology, Istituto Nazionale Tumori "Fondazione Giovanni Pascale", IRCCS, 80131, Naples, Italy
| | - Camillo Palmieri
- Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Graecia", Viale Europa, 88100, Catanzaro, Italy
| | - Elisabetta Caiazzo
- Department of Pharmacy, University of Naples "Federico II", Via Domenico Montesano 49, 80131, Naples, Italy
| | - Carla Cicala
- Department of Pharmacy, University of Naples "Federico II", Via Domenico Montesano 49, 80131, Naples, Italy
| | - Claudio Bellevicine
- Department of Public Health, University of Naples "Federico II", Via Sergio Pansini 5, 80131, Naples, Italy
| | - Cristina Falcone
- Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Graecia", Viale Europa, 88100, Catanzaro, Italy
| | - Eleonora Vecchio
- Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Graecia", Viale Europa, 88100, Catanzaro, Italy
| | - Antonio Pisano
- Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Graecia", Viale Europa, 88100, Catanzaro, Italy
| | - Simona Ceglia
- Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Graecia", Viale Europa, 88100, Catanzaro, Italy
| | - Selena Mimmi
- Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Graecia", Viale Europa, 88100, Catanzaro, Italy
| | - Enrico Iaccino
- Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Graecia", Viale Europa, 88100, Catanzaro, Italy
| | - Annamaria de Laurentiis
- Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Graecia", Viale Europa, 88100, Catanzaro, Italy
| | - Marilena Pontoriero
- Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Graecia", Viale Europa, 88100, Catanzaro, Italy
| | - Valter Agosti
- Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Graecia", Viale Europa, 88100, Catanzaro, Italy
| | - Giancarlo Troncone
- Department of Public Health, University of Naples "Federico II", Via Sergio Pansini 5, 80131, Naples, Italy
| | - Chiara Mignogna
- Science of Health Department, University of Catanzaro "Magna Graecia", Italy
| | - Giuseppe Palma
- Molecular Biology and Viral Oncogenesis Unit, Department of Experimental Oncology, Istituto Nazionale Tumori "Fondazione Giovanni Pascale", IRCCS, 80131, Naples, Italy
| | - Claudio Arra
- Molecular Biology and Viral Oncogenesis Unit, Department of Experimental Oncology, Istituto Nazionale Tumori "Fondazione Giovanni Pascale", IRCCS, 80131, Naples, Italy
| | - Massimo Mallardo
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Via Sergio Pansini 5, 80131, Naples, Italy
| | - Franco Maria Buonaguro
- Molecular Biology and Viral Oncogenesis Unit, Department of Experimental Oncology, Istituto Nazionale Tumori "Fondazione Giovanni Pascale", IRCCS, 80131, Naples, Italy
| | - Giuseppe Scala
- Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Graecia", Viale Europa, 88100, Catanzaro, Italy
| | - Ileana Quinto
- Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Graecia", Viale Europa, 88100, Catanzaro, Italy
| |
Collapse
|
6
|
Van Nuffel A, Ariën KK, Stove V, Schindler M, O'Neill E, Schmökel J, Van de Walle I, Naessens E, Vanderstraeten H, Van Landeghem K, Taghon T, Pulkkinen K, Saksela K, Garcia JV, Fackler OT, Kirchhoff F, Verhasselt B. Primate lentiviral Nef proteins deregulate T-cell development by multiple mechanisms. Retrovirology 2013; 10:137. [PMID: 24237970 PMCID: PMC3906981 DOI: 10.1186/1742-4690-10-137] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 10/28/2013] [Indexed: 01/21/2023] Open
Abstract
Background A nef gene is present in all primate lentiviral genomes and is important for high viral loads and progression to AIDS in human or experimental macaque hosts of HIV or SIV, respectively. In these hosts, infection of the thymus results in a decreased output of naive T cells that may contribute to the development of immunodeficiency. We have previously shown that HIV-1 subtype B Nef proteins can block human T-cell development. However, the underlying mechanism(s) and the conservation of this Nef function between different groups of HIV and SIV remained to be determined. Results We investigated whether reduction of thymic output is a conserved function of highly divergent lentiviral Nef proteins including those from both types of human immunodeficiency viruses (HIV-1 and HIV-2), their direct simian counterparts (SIVcpz, SIVgor and SIVsmm, respectively), and some additional SIV strains. We found that expression of most of these nef alleles in thymocyte progenitors impaired T-cell development and reduced thymic output. For HIV-1 Nef, binding to active p21 protein (Cdc42/Rac)-activated kinase (PAK2) was a major determinant of this function. In contrast, selective disruption of PAK2 binding did not eliminate the effect on T-cell development of SIVmac239 Nef, as was shown by expressing mutants in a newly discovered PAK2 activating structural motif (PASM) constituted by residues I117, H121, T218 and Y221, as well as previously described mutants. Rather, down-modulation of cell surface CD3 was sufficient for reduced thymic output by SIVmac Nef, while other functions of SIV Nefs contributed. Conclusions Our results indicate that primate lentiviral Nef proteins impair development of thymocyte precursors into T cells in multiple ways. The interaction of HIV-1 Nef with active PAK2 by HIV-1 seem to be most detrimental, and downregulation of CD3 by HIV-2 and most SIV Nef proteins sufficient for reduced thymic output. Since the reduction of thymic output by Nef is a conserved property of divergent lentiviruses, it is likely to be relevant for peripheral T-cell depletion in poorly adapted primate lentiviral infections.
Collapse
Affiliation(s)
- Anouk Van Nuffel
- Department of Clinical Chemistry, Microbiology, and Immunology, Ghent University, Ghent, Belgium.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Tolerance has its limits: how the thymus copes with infection. Trends Immunol 2013; 34:502-10. [PMID: 23871487 DOI: 10.1016/j.it.2013.06.004] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 05/25/2013] [Accepted: 06/17/2013] [Indexed: 01/11/2023]
Abstract
The thymus is required for T cell differentiation; a process that depends on which antigens are encountered by thymocytes, the environment surrounding the differentiating cells, and the thymic architecture. These features are altered by local infection of the thymus and by the inflammatory mediators that accompany systemic infection. Although once believed to be an immune privileged site, it is now known that antimicrobial responses are recruited to the thymus. Resolving infection in the thymus is important because chronic persistence of microbes impairs the differentiation of pathogen-specific T cells and diminishes resistance to infection. Understanding how these mechanisms contribute to disease susceptibility, particularly in infants with developing T cell repertoires, requires further investigation.
Collapse
|
8
|
Abstract
Human immunodeficiency virus (HIV) pathogenesis has proven to be quite complex and dynamic with most of the critical events (e.g., transmission, CD4(+) T-cell destruction) occurring in mucosal tissues. In addition, although the resulting disease can progress over years, it is clear that many critical events happen within the first few weeks of infection when most patients are unaware that they are infected. These events occur predominantly in tissues other than the peripheral blood, particularly the gastrointestinal tract, where massive depletion of CD4(+) T cells occurs long before adverse consequences of HIV infection are otherwise apparent. Profound insights into these early events have been gained through the use of nonhuman primate models, which offer the opportunity to examine the early stages of infection with the simian immunodeficiency virus (SIV), a close relative of HIV that induces an indistinguishable clinical picture from AIDS in Asian primate species, but importantly, fails to cause disease in its natural African hosts, such as sooty mangabeys and African green monkeys. This article draws from data derived from both human and nonhuman primate studies.
Collapse
Affiliation(s)
- A A Lackner
- Tulane National Primate Research Center, Tulane University Health Science Center, Covington, LA 70443, USA.
| | | | | |
Collapse
|
9
|
Zeng M, Haase AT, Schacker TW. Lymphoid tissue structure and HIV-1 infection: life or death for T cells. Trends Immunol 2012; 33:306-14. [PMID: 22613276 DOI: 10.1016/j.it.2012.04.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 03/22/2012] [Accepted: 04/04/2012] [Indexed: 01/07/2023]
Abstract
Secondary lymphoid tissue (LT) structure facilitates immune responses and maintains homeostasis of T cells through production of survival factors, such as interleukin (IL)-7 that is 'posted' on the stromal fibroblastic reticular cell (FRC) network on which T cells traffic. Here, we examine the pathological changes that occur in LTs during HIV and simian immunodeficiency virus (SIV) infection. Immune activation leads to collagen deposition and loss of the FRC network itself. This decreases access to IL-7 and reduces the major source of IL-7, both of which deplete naïve T cells to limit immune reconstitution with antiretroviral treatment. We discuss the implications of LT structure damage for the timing of antiretroviral therapy and consider the development of adjunctive antifibrotic agents to improve immune reconstitution in HIV infection.
Collapse
Affiliation(s)
- Ming Zeng
- Department of Microbiology, Medical School, University of Minnesota, MMC 196, 420 Delaware Street S.E., Minneapolis, MN 55455, USA
| | | | | |
Collapse
|
10
|
Vassena L, Miao H, Cimbro R, Malnati MS, Cassina G, Proschan MA, Hirsch VM, Lafont BA, Morre M, Fauci AS, Lusso P. Treatment with IL-7 prevents the decline of circulating CD4+ T cells during the acute phase of SIV infection in rhesus macaques. PLoS Pathog 2012; 8:e1002636. [PMID: 22511868 PMCID: PMC3325214 DOI: 10.1371/journal.ppat.1002636] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Accepted: 02/25/2012] [Indexed: 02/04/2023] Open
Abstract
Although treatment with interleukin-7 (IL-7) was shown to transiently expand the naïve and memory T-cell pools in patients with chronic HIV-1 infection receiving antiretroviral therapy (ART), it is uncertain whether a full immunologic reconstitution can be achieved. Moreover, the effects of IL-7 have never been evaluated during acute HIV-1 (or SIV) infection, a critical phase of the disease in which the most dramatic depletion of CD4+ T cells is believed to occur. In the present study, recombinant, fully glycosylated simian IL-7 (50 µg/kg, s.c., once weekly for 7 weeks) was administered to 6 rhesus macaques throughout the acute phase of infection with a pathogenic SIV strain (mac251); 6 animals were infected at the same time and served as untreated controls. Treatment with IL-7 did not cause clinically detectable side effects and, despite the absence of concomitant ART, did not induce significant increases in the levels of SIV replication except at the earliest time point tested (day 4 post-infection). Strikingly, animals treated with IL-7 were protected from the dramatic decline of circulating naïve and memory CD4+ T cells that occurred in untreated animals. Treatment with IL-7 induced only transient T-cell proliferation, but it was associated with sustained increase in the expression of the anti-apoptotic protein Bcl-2 on both CD4+ and CD8+ T cells, persistent expansion of all circulating CD8+ T-cell subsets, and development of earlier and stronger SIV Tat-specific T-cell responses. However, the beneficial effects of IL-7 were not sustained after treatment interruption. These data demonstrate that IL-7 administration is effective in protecting the CD4+ T-cell pool during the acute phase of SIV infection in macaques, providing a rationale for the clinical evaluation of this cytokine in patients with acute HIV-1 infection. The development of highly effective cocktails of antiretroviral drugs has had a major impact on the survival and quality of life of individuals with HIV-1 infection. Yet, current protocols often fail to fully restore the immunologic function, a limitation that has prompted the clinical evaluation of immune-reconstitution agents, such as IL-7, as adjuvant therapies. To date, however, IL-7 has been tested exclusively in patients with chronic HIV-1 infection, while it appears that the immune system is irreparably damaged during acute primary infection, within the first few weeks after encountering the virus. We used a macaque model to show that treatment with IL-7 has beneficial effects if implemented during the acute phase of infection with SIV, the simian AIDS virus. Early administration of IL-7 was safe and effectively protected CD4+ T cells, the primary target cells for the virus, from the marked decline that typically occurs during acute SIV infection. Furthermore, IL-7 boosted the development of antiviral immune responses. Thus, IL-7 might be an effective adjuvant therapy in acute HIV-1 infection, which can protect the pool of CD4+ T cells before it is irreversibly compromised by the action of the virus.
Collapse
Affiliation(s)
- Lia Vassena
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- Human Virology Unit, DIBIT-HSR, Milano, Italy
| | - Huiyi Miao
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Raffaello Cimbro
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | | | | | - Michael A. Proschan
- Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Vanessa M. Hirsch
- Laboratory of Molecular Medicine, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Bernard A. Lafont
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | | | - Anthony S. Fauci
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Paolo Lusso
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
| |
Collapse
|
11
|
The majority of freshly sorted simian immunodeficiency virus (SIV)-specific CD8(+) T cells cannot suppress viral replication in SIV-infected macrophages. J Virol 2012; 86:4682-7. [PMID: 22318140 DOI: 10.1128/jvi.06324-11] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) primarily infect activated CD4(+) T cells but can infect macrophages. Surprisingly, ex vivo tetramer-sorted SIV-specific CD8(+) T cells that eliminated and suppressed viral replication in SIV-infected CD4(+) T cells failed to do so in SIV-infected macrophages. It is possible, therefore, that while AIDS virus-infected macrophages constitute only a small percentage of all virus-infected cells, they may be relatively resistant to CD8(+) T cell-mediated lysis and continue to produce virus over long periods of time.
Collapse
|
12
|
Chrobak P, Simard MC, Bouchard N, Ndolo TM, Guertin J, Hanna Z, Dave V, Jolicoeur P. HIV-1 Nef Disrupts Maturation of CD4+T Cells through CD4/Lck Modulation. THE JOURNAL OF IMMUNOLOGY 2010; 185:3948-59. [DOI: 10.4049/jimmunol.1001064] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
13
|
Kuhnt LA, Jennings RN, Brawner WR, Hathcock JT, Carreno AD, Johnson CM. Magnetic resonance imaging of radiation-induced thymic atrophy as a model for pathologic changes in acute feline immunodeficiency virus infection. J Feline Med Surg 2009; 11:977-84. [PMID: 19540785 PMCID: PMC11318762 DOI: 10.1016/j.jfms.2009.04.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/22/2009] [Indexed: 01/26/2023]
Abstract
The development of a protocol to reproducibly induce thymic atrophy, as occurs in feline immunodeficiency virus (FIV) infection and other immunosuppressive diseases, and to consistently estimate thymic volume, provides a valuable tool in the search of innovative and novel therapeutic strategies. Magnetic resonance imaging (MRI) using the short tau inversion recovery (STIR) technique, with fat suppression properties, was determined to provide an optimized means of locating, defining, and quantitatively estimating thymus volume in young cats. Thymic atrophy was induced in four, 8-10-week-old kittens with a single, directed 500 cGy dose of 6 MV X-rays from a clinical linear accelerator, and sequential MR images of the cranial mediastinum were collected at 2, 7, 14, and 21 days post irradiation (PI). Irradiation induced a severe reduction in thymic volume, which was decreased, on average, to 47% that of normal, by 7 days PI. Histopathology confirmed marked, diffuse thymic atrophy, characterized by reduced thymic volume, decreased overall cellularity, increased apoptosis, histiocytosis, and reduced distinction of the corticomedullary junction, comparable to that seen in acute FIV infection. Beginning on day 7 PI, thymic volumes rebounded slightly and continued to increase over the following 14 days, regaining 3-35% of original volume. These findings demonstrate the feasibility and advantages of using this non-invasive, in vivo imaging technique to measure and evaluate changes in thymic volume in physiologic and experimental situations. All experimental protocols in this study were approved by the Institutional Animal Care and Use Committee (IACUC) at Auburn University.
Collapse
Affiliation(s)
- Leah A Kuhnt
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA.
| | | | | | | | | | | |
Collapse
|
14
|
Williams KC, Burdo TH. HIV and SIV infection: the role of cellular restriction and immune responses in viral replication and pathogenesis. APMIS 2009; 117:400-12. [PMID: 19400864 DOI: 10.1111/j.1600-0463.2009.02450.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) have a long biological history. Both viruses evolved from Africa and remnants of them can be found in the 'fossil record' of several species in which they are not endemic. SIV remains endemic in several species of monkeys in Africa where it does not cause immune deficiency. HIV and SIV actively replicate within humans and Asian non-human primates, despite cellular and genetic viral restriction factors and genes, and at times robust innate and adaptive immune responses. While Lentiviruses are considered 'slow viruses' it is clear in humans and susceptible Asian monkeys that virus production is rapid and highly active. This results in a massive loss of CD4+ memory effector T cells early after infection and a continued race between viral evolution, cytotoxic lymphocytes, and failed neutralizing antibody responses. Concurrently, HIV and SIV can infect monocyte/macrophage populations in blood and more importantly in tissues, including the central nervous system, where the virus can remain sequestered and not cleared by anti-retroviral therapy, and hide for years. This review will discuss species and cellular barriers to infection, and the role of innate and acquired immunity with infection and pathogenesis of HIV and SIV in select species.
Collapse
|
15
|
Lederer S, Favre D, Walters KA, Proll S, Kanwar B, Kasakow Z, Baskin CR, Palermo R, McCune JM, Katze MG. Transcriptional profiling in pathogenic and non-pathogenic SIV infections reveals significant distinctions in kinetics and tissue compartmentalization. PLoS Pathog 2009; 5:e1000296. [PMID: 19214219 PMCID: PMC2633618 DOI: 10.1371/journal.ppat.1000296] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Accepted: 01/13/2009] [Indexed: 11/26/2022] Open
Abstract
Simian immunodeficiency virus (SIV) infection leads to AIDS in experimentally infected macaques, whereas natural reservoir hosts exhibit limited disease and pathology. It is, however, unclear how natural hosts can sustain high viral loads, comparable to those observed in the pathogenic model, without developing severe disease. We performed transcriptional profiling on lymph node, blood, and colon samples from African green monkeys (natural host model) and Asian pigtailed macaques (pathogenic model) to directly compare gene expression patterns during acute pathogenic versus non-pathogenic SIV infection. The majority of gene expression changes that were unique to either model were detected in the lymph nodes at the time of peak viral load. Results suggest a shift toward cellular stress pathways and Th1 profiles during pathogenic infection, with strong and sustained type I and II interferon responses. In contrast, a strong type I interferon response was initially induced during non-pathogenic infection but resolved after peak viral load. The natural host also exhibited controlled Th1 profiles and better preservation of overall cell homeostasis. This study identified gene expression patterns that are specific to disease susceptibility, tissue compartmentalization, and infection duration. These patterns provide a unique view of how host responses differ depending upon lentiviral infection outcome. Simian immunodeficiency virus (SIV) does not cause disease in African green monkeys (a natural host for the virus), whereas experimentally infected Asian macaques (a non-natural host) develop a progressive disease that is similar to that which occurs in HIV-infected humans. Insight into how HIV causes disease and leads to development of AIDS may therefore be gained by comparing the response of natural and non-natural hosts to SIV infection. To this end, we examined changes that occurred in gene expression levels over time and in multiple tissues derived from African green monkeys and Asian macaques experimentally infected with SIV. Infection leads to host-specific gene expression patterns in lymph nodes, blood, and colon. The natural and non-natural hosts differed with respect to the timing, intensity, and duration of infection-induced gene expression changes associated with inflammation and response to stress.
Collapse
Affiliation(s)
- Sharon Lederer
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - David Favre
- Department of Medicine, Division of Experimental Medicine, University of California, San Francisco, California, United States of America
| | - Kathie-Anne Walters
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Sean Proll
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Bittoo Kanwar
- Department of Medicine, Division of Experimental Medicine, University of California, San Francisco, California, United States of America
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, University of California, San Francisco, California, United States of America
| | - Zeljka Kasakow
- Department of Medicine, Division of Experimental Medicine, University of California, San Francisco, California, United States of America
| | - Carole R. Baskin
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
- Washington National Primate Research Center, University of Washington, Seattle, Washington, United States of America
| | - Robert Palermo
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Joseph M. McCune
- Department of Medicine, Division of Experimental Medicine, University of California, San Francisco, California, United States of America
| | - Michael G. Katze
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
- Washington National Primate Research Center, University of Washington, Seattle, Washington, United States of America
- * E-mail:
| |
Collapse
|
16
|
Borda JT, Alvarez X, Mohan M, Hasegawa A, Bernardino A, Jean S, Aye P, Lackner AA. CD163, a marker of perivascular macrophages, is up-regulated by microglia in simian immunodeficiency virus encephalitis after haptoglobin-hemoglobin complex stimulation and is suggestive of breakdown of the blood-brain barrier. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 172:725-37. [PMID: 18276779 DOI: 10.2353/ajpath.2008.070848] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Macrophages and microglia are the major cell types infected by human immunodeficiency virus and simian immunodeficiency virus (SIV) in the central nervous system. Microglia are likely infected in vivo, but evidence of widespread productive infection (ie, presence of viral RNA and protein) is lacking. This conclusion is controversial because, unlike lymphocytes, macrophages and microglia cannot be discreetly immunophenotyped. Of particular interest in the search for additional monocyte/macrophage-lineage cell markers is CD163; this receptor for haptoglobin-hemoglobin (Hp-Hb) complex, which forms in plasma following erythrolysis, is expressed exclusively on cells of monocyte/macrophage lineage. We examined CD163 expression in vitro and in vivo by multiple techniques and at varying times after SIV infection in macaques with or without encephalitis. In normal and acutely SIV-infected animals, and in SIV-infected animals without encephalitis, CD163 expression was detected in cells of monocyte/macrophage lineage, including perivascular macrophages, but not in parenchymal microglia. However, in chronically infected animals with encephalitis, CD163 expression was detected in activated microglia surrounding SIV encephalitis lesions in the presence of Hp-Hb complex, suggesting leakage of the blood-brain barrier. CD163 expression was also induced on microglia in vitro after stimulation with Hp-Hb complex. We conclude that CD163 is a selective marker of perivascular macrophages in normal macaques and during the early phases of SIV infection; however, later in infection in animals with encephalitis, CD163 is also expressed by microglia, which are probably activated as a result of vascular compromise.
Collapse
Affiliation(s)
- Juan T Borda
- Division of Comparative Pathology, Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, Louisiana 70433, USA
| | | | | | | | | | | | | | | |
Collapse
|
17
|
|
18
|
Kolenda-Roberts HM, Kuhnt LA, Jennings RN, Mergia A, Gengozian N, Johnson CM. Immunopathogenesis of feline immunodeficiency virus infection in the fetal and neonatal cat. FRONT BIOSCI-LANDMRK 2007; 12:3668-82. [PMID: 17485330 PMCID: PMC2278015 DOI: 10.2741/2343] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The global incidence of pediatric HIV infection is estimated at 2.3 million children, most acquiring the infection from their mothers in utero, peripartum, or postpartum. Pediatric HIV infection typically causes a rapidly progressive disease when compared with adult infection, due in part to the profound susceptibility of the neonatal thymus to productive infection or degenerative changes. Failed production of naive T-lymphocytes further limits the success of antiviral therapy to restore immunologic function. In this review, we explore the use of feline immunodeficiency virus (FIV) infection of domestic cats as an animal model for pediatric HIV infection. Cats infected with FIV represent the smallest host of a naturally occurring lentivirus, and the immunodeficiency syndrome elicited by FIV infection is similar to that of HIV-AIDS. The feline-FIV model uniquely reproduces several key aspects of immunosuppressive lentivirus infection of the thymus, allowing investigators to define viral determinants of pathogenicity, influence of host age on disease outcome, and therapeutic strategies to restore thymus function.
Collapse
Affiliation(s)
- Holly M. Kolenda-Roberts
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, FL
| | - Leah A. Kuhnt
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL
| | - Ryan N. Jennings
- Veterinary Medical Program, College of Veterinary Medicine, Michigan State University, East Lansing, MI
| | - Ayalew Mergia
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, FL
| | - Nazareth Gengozian
- Department of Medicine, Graduate School of Medicine, University of Tennessee, and the Thompson Cancer Survival Center, Knoxville, TN
| | - Calvin M. Johnson
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL
| |
Collapse
|
19
|
Abstract
The pathogenesis of AIDS has proven to be quite complex and dynamic, with most of the critical events (e.g., transmission, CD4(+) T cell destruction) occurring in tissues that are not easily accessible for analysis. In addition, although the disease can progress over years, many critical events happen within the first few weeks of infection, when most patients are unaware that they are infected. The nonhuman primate model of AIDS has been used extensively to fill these gaps in our understanding of AIDS pathogenesis.
Collapse
Affiliation(s)
- Andrew A Lackner
- Tulane National Primate Research Center, Covington, Louisiana 70433, USA.
| | | |
Collapse
|
20
|
Viollet L, Monceaux V, Petit F, Ho Tsong Fang R, Cumont MC, Hurtrel B, Estaquier J. Death of CD4+ T cells from lymph nodes during primary SIVmac251 infection predicts the rate of AIDS progression. THE JOURNAL OF IMMUNOLOGY 2007; 177:6685-94. [PMID: 17082581 DOI: 10.4049/jimmunol.177.10.6685] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Immunological and virological events that occur during the earliest stages of SIV infection are now considered to have a major impact on subsequent disease progression. In the present study, we demonstrate a clear correlation between progression to AIDS and the rate of in vitro CD4+ (but not CD8+) T cell death in lymph nodes. The dying CD4+ T cells were effector memory T cells, which are critical for the immune response to pathogens. However, there was no correlation between the rate of the viral replication within lymph nodes and the extent of Fas ligand-mediated death, despite the increased sensitivity of CD4+ T cells to death in response to recombinant human Fas ligand. CD4+ T cell death was caspase and apoptosis-inducing factor independent but was clearly associated with mitochondrion damage. Interestingly, higher expression levels of the active form of Bak, a proapoptotic molecule involved in mitochondrial membrane permeabilization, were observed in SIV-infected macaques progressing more rapidly to AIDS. Finally, we demonstrated that the strain of SIV we used requires CCR5 and BOB/GRP15 molecules as coreceptors and caused death of unstimulated noncycling primary CD4+ T cells. Altogether, these results demonstrate that CD4+ T cell death occurring early after SIV infection is a crucial determinant of progression to AIDS and that it is mediated by the intrinsic death pathway.
Collapse
Affiliation(s)
- Laurence Viollet
- Unité de Physiopathologie des Infections Lentivirales, Institut Pasteur, Paris, France
| | | | | | | | | | | | | |
Collapse
|
21
|
Meissner EG, Zhang L, Jiang S, Su L. Fusion-induced apoptosis contributes to thymocyte depletion by a pathogenic human immunodeficiency virus type 1 envelope in the human thymus. J Virol 2006; 80:11019-30. [PMID: 16956934 PMCID: PMC1642149 DOI: 10.1128/jvi.01382-06] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Accepted: 08/30/2006] [Indexed: 01/09/2023] Open
Abstract
The mechanisms of CD4(+) T-cell depletion during human immunodeficiency virus type 1 (HIV-1) infection remain incompletely characterized. Of particular importance is how CD4(+) T cells are depleted within the lymphoid organs, including the lymph nodes and thymus. Herein we characterize the pathogenic mechanisms of an envelope from a rapid progressor (R3A Env) in the NL4-3 backbone (NL4-R3A) which is able to efficiently replicate and deplete CD4(+) thymocytes in the human fetal-thymus organ culture (HF-TOC). We demonstrate that uninterrupted replication is required for continual thymocyte depletion. During depletion, NL4-R3A induces an increase in thymocytes which uptake 7AAD, a marker of cell death, and which express active caspase-3, a marker of apoptosis. While 7AAD uptake is observed predominantly in uninfected thymocytes (p24(-)), active caspase-3 is expressed in both infected (p24(+)) and uninfected thymocytes (p24(-)). When added to HF-TOC with ongoing infection, the protease inhibitor saquinavir efficiently suppresses NL4-R3A replication. In contrast, the fusion inhibitors T20 and C34 allow for sustained HIV-1 production. Interestingly, T20 and C34 effectively prevent thymocyte depletion in spite of this sustained replication. Apoptosis of both p24(-) and p24(+) thymocytes appears to be envelope fusion dependent, as T20, but not saquinavir, is capable of reducing thymocyte apoptosis. Together, our data support a model whereby pathogenic envelope-dependent fusion contributes to thymocyte depletion in HIV-1-infected thymus, correlated with induction of apoptosis in both p24(+) and p24(-) thymocytes.
Collapse
Affiliation(s)
- Eric G Meissner
- Lineberger Comprehensive Cancer Center, CB#7295, Chapel Hill, NC 27599, USA
| | | | | | | |
Collapse
|
22
|
Gurney KB, Uittenbogaart CH. Human immunodeficiency virus persistence and production in T-cell development. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2006; 13:1237-45. [PMID: 16988009 PMCID: PMC1656539 DOI: 10.1128/cvi.00184-06] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1) replication depends on CD4 and coreceptor expression as well as host factors associated with the activation state of the cell. To determine the impact of the activation stage of thymocytes on the HIV-1 life cycle, we investigated R5 and X4 HIV-1 entry, reverse transcription, and expression in discrete thymocyte subsets at different stages of T-cell development. Early after infection, preferential entry and replication of R5 HIV-1 were predominantly detected in mature CD3(+/hi) CD27(+) thymocytes. Thus, R5 HIV-1 targets the stage of development where thymocytes acquire functional responsiveness, which has important implications for HIV pathogenesis. In contrast, X4 HIV-1 expression and replication were primarily found in immature CD3(-/+/low) CD27(-) CD69(-) thymocytes. HIV-1 proviral burden and virus expression in thymocyte subsets correlated with the expression of the highest levels of the respective coreceptor. R5 and X4 HIV-1 entered and completed reverse transcription in all subsets tested, indicating that the activation state of thymocytes and coreceptor expression are sufficient to support full reverse transcription throughout development. Although R5 HIV-1 is expressed mainly in mature CD3(+/hi) CD27(+) thymocytes, 5.3% of HIV-1-infected immature thymocytes express R5 HIV-1, indicating that potentially latent viral DNA can be established early in T-cell development.
Collapse
Affiliation(s)
- Kevin B Gurney
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA School of Medicine, Los Angeles, CA 90095-1747, USA
| | | |
Collapse
|
23
|
Hurtrel B, Petit F, Arnoult D, Müller-Trutwin M, Silvestri G, Estaquier J. Apoptosis in SIV infection. Cell Death Differ 2006; 12 Suppl 1:979-90. [PMID: 15818408 DOI: 10.1038/sj.cdd.4401600] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Pathogenic human immunodeficiency virus (HIV)/Simian immunodeficiency virus (SIV) infection is associated with increased T-cell apoptosis. In marked contrast to HIV infection in humans and SIV infection in macaques, the SIV infection of natural host species is typically nonpathogenic despite high levels of viral replication. In these nonpathogenic primate models, no observation of T-cell apoptosis was observed, suggesting that either SIV is less capable of directly inducing apoptosis in natural hosts (likely as a result of coevolution/coadaptation with the host) or, alternatively, that the indirect T-cell apoptosis plays the key role in determining the HIV-associated T-cell depletion and progression to acquired immune deficiency syndrome (AIDS). Understanding the molecular and cellular mechanisms responsible for the disease-free equilibrium in natural hosts for SIV infection, including those determining the absence of high levels of T-cell apoptosis, is likely to provide important clues regarding the mechanisms of AIDS pathogenesis in humans.
Collapse
Affiliation(s)
- B Hurtrel
- Unité de Physiopathologie des Infections Lentivirales, Institut Pasteur, Paris, cedex 15, France
| | | | | | | | | | | |
Collapse
|
24
|
Schmitt N, Nugeyre MT, Scott-Algara D, Cumont MC, Barré-Sinoussi F, Pancino G, Israël N. Differential susceptibility of human thymic dendritic cell subsets to X4 and R5 HIV-1 infection. AIDS 2006; 20:533-42. [PMID: 16470117 DOI: 10.1097/01.aids.0000210607.63138.bc] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Human thymus can be infected by HIV-1 with potential consequences on immune regeneration and homeostasis. We previously showed that CD4 thymocytes preferentially replicate CXCR4 tropic (X4) HIV-1 dependently on interleukin (IL)-7. Here we addressed the susceptibility of thymic dendritic cells (DC) to HIV-1 infection. METHODS We investigated the replication ability of CXCR4 or CCR5 (R5) tropic HIV-1 in thymic micro-explants as well as in isolated thymic CD11clowCD14- DC, CD11chighCD14+ DC and plasmacytoid DC subsets. RESULTS Thymic tissue was productively infected by both X4 and R5 viruses. However, X4 but not R5 HIV-1 replication was enhanced by IL-7 in thymic micro-explants, suggesting that R5 virus replication occurred in cells other than thymocytes. Indeed, we found that R5 HIV-1 replicated efficiently in DC isolated from thymic tissue. The replicative capacity of X4 and R5 viruses differed according to the different DC subsets. R5 but not X4 HIV-1 efficiently replicated in CD11chighCD14+ DC. In contrast, no HIV-1 replication was detected in CD11clowCD14- DC. Both X4 and R5 viruses efficiently replicated in plasmacytoid DC, which secreted interferon-alpha upon HIV-1 exposure. Productive HIV-1 infection also caused DC loss, consistent with different permissivity of each DC subset. CONCLUSIONS Thymic DC sustain high levels of HIV-1 replication. DC might thus be the first target for R5 HIV-1 infection of thymus, acting as a Trojan horse for HIV-1 spread to thymocytes. Furthermore, DC death induced by HIV-1 infection may affect thymopoiesis.
Collapse
Affiliation(s)
- Nathalie Schmitt
- Unité de Régulation des Infections Rétrovirales, Institut Pasteur, Paris, France.
| | | | | | | | | | | | | |
Collapse
|
25
|
Hayes KA, Köksoy S, Phipps AJ, Buck WR, Kociba GJ, Mathes LE. Lentivirus-specific cytotoxic T-lymphocyte responses are rapidly lost in thymectomized cats infected with feline immunodeficiency virus. J Virol 2005; 79:8237-42. [PMID: 15956569 PMCID: PMC1143713 DOI: 10.1128/jvi.79.13.8237-8242.2005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To what extent the thymus is needed to preserve the virus-specific cytotoxic T-lymphocyte (CTL) response of lentivirus-infected adults is unclear. Presented here is the first definitive study using thymectomized (ThX) animals to directly evaluate the contribution of thymic function to lentivirus-specific CTL response and the control of lentivirus infections. ThX and mock-ThX cats were inoculated with feline immunodeficiency virus (FIV) and monitored for their FIV-specific CTL responses. Early in infection, both FIV-ThX and FIV-mock-ThX cats produced similar CTL responses, but surprisingly, after 20 weeks, the FIV-ThX cats showed a statistically significant loss of FIV-specific CTL activity, while FIV-infected cats with intact thymuses continued to maintain FIV-specific CTL. The loss of CTL did not affect plasma virus load, which remained elevated for both groups. These results emphasize the importance of thymic integrity in maintaining immunity to lentiviruses, but also bring into question the notion that virus load is regulated predominantly by the virus-specific CTL response.
Collapse
Affiliation(s)
- Kathleen A Hayes
- Department of Veterinary Biosciences, Center for Retrovirus Research, The Ohio State University, 1925 Coffey Road, Columbus, Ohio 43210, USA
| | | | | | | | | | | |
Collapse
|
26
|
Ho Tsong Fang R, Khatissian E, Monceaux V, Cumont MC, Beq S, Ameisen JC, Aubertin AM, Israël N, Estaquier J, Hurtrel B. Disease progression in macaques with low SIV replication levels: on the relevance of TREC counts. AIDS 2005; 19:663-73. [PMID: 15821392 DOI: 10.1097/01.aids.0000166089.93574.5a] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND An attenuated immunodeficiency virus has been long considered innocuous. Nevertheless, converging data suggest that low levels of viral replication can still provoke AIDS. Pathogenesis of these attenuated infections is not understood. OBJECTIVES To determine the pathogenicity of a long-term attenuated infection and to delineate T-cell dynamics during such an infection. METHODS This is a cross-sectional study of 12 rhesus macaques infected with SIV Delta nef for 8 years. We evaluated apoptosis (annexin V), activation (HLA-DR, Ki67), and newly generated T cells (TCR excision circle: TREC). RESULTS Infection with SIV Delta nef induced pathological CD4 T-cell depletion after 8 years of infection. Virus replication and CD8 T-cell activation positively correlated with the rate of disease progression. The frequency of TREC within CD8+CD45RA+ cells increased in SIV Delta nef-infected animals compared to age-matched non-infected controls. Moreover, in the cohort of infected animals, TREC+CD45RA+CD4+ T-cell counts correlated strongly with non-progression to AIDS. The animal with the lowest rate of disease progression exhibited a 115-fold increase in TREC+CD45RA+CD4+ T-cell counts compared to age-matched non-infected controls. In contrast, the animal showing the fastest rate of progression to AIDS displayed 600-fold lower TREC+CD45RA+CD4+ T-cell counts compared to age-matched non-infected controls. CONCLUSIONS Our results suggest that the thymus plays a major role in the pathogenesis of an attenuated SIV infection and that a sustained thymic output could maintain CD4 T-cell homeostasis in the context of low viral loads.
Collapse
Affiliation(s)
- Raphaël Ho Tsong Fang
- Unité de Physiopathologie des Infections Lentivirales, Institut Pasteur, Paris, France.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Thiebot H, Vaslin B, Derdouch S, Bertho JM, Mouthon F, Prost S, Gras G, Ducouret P, Dormont D, Le Grand R. Impact of bone marrow hematopoiesis failure on T-cell generation during pathogenic simian immunodeficiency virus infection in macaques. Blood 2005; 105:2403-9. [PMID: 15388577 DOI: 10.1182/blood-2004-01-0025] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
AbstractExperimental infection of macaques with pathogenic strains of simian immunodeficiency virus (SIV) represents one of the most relevant animal models for studying HIV pathogenesis. In this study, we demonstrated a significant decrease in the generation of CD4+ T cells from bone marrow (BM) CD34+ progenitors in macaques infected with SIVmac251. This decrease appears to result from changes in the clonogenic potential of BM progenitors of both the myeloid and lymphoid lineages. We also demonstrated a significant decrease in the numbers of the most immature long-term culture-initiating cells (LTC-ICs). Hematopoietic failure occurred as early as primary infection, in the absence of CD34+ BM cell infection and was not related to plasma viral load. No major change was observed in the phenotype of BM CD34+ cells from infected macaques, including apoptosis markers such as annexin V staining and BcL-2 expression, but a significantly higher that normal proportion of cells were in the G0/G1 phase. This is the first demonstration that failure of BM hematopoiesis results in impaired T-cell production, which may contribute to the disruption of T-lymphocyte homeostasis characteristic of pathogenic lentiviral infections in primates.
Collapse
Affiliation(s)
- Hugues Thiebot
- CEA, Laboratoire d'Immuno-Pathologie Expérimentale, Service de Neurovirologie, Centre de Recherches du Service de Santé des Armées, Ecole Pratique des Hautes Etudes, Institut Paris-Sud sur les Cytokines, Université Paris XI, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Arron ST, Ribeiro RM, Gettie A, Bohm R, Blanchard J, Yu J, Perelson AS, Ho DD, Zhang L. Impact of thymectomy on the peripheral T cell pool in rhesus macaques before and after infection with simian immunodeficiency virus. Eur J Immunol 2005; 35:46-55. [PMID: 15593297 DOI: 10.1002/eji.200424996] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The goal of this study was to define, by surgical removal of the thymus in juvenile rhesus macaques, the role of the thymus in peripheral T cell homeostasis and to assess the significance of thymic output in SIV infection. By monitoring the changes in phenotypic T cell markers as well as in the numbers of TCR excisional circles--a recently described marker for recent thymic emigrants--following thymectomy, we present evidence that surgical thymectomy in juvenile macaques results in a faster decay of peripheral CD4(+) cells, but does not cause a substantial shift in CD45RA(+) and CD45RA(-) populations. We were able to measure a thymic output of 0.32% and 0.21% per day of CD4(+) and CD8(+) cells, respectively. No compensatory extra-thymic source was detected in lymphoid tissues, although there was a small compensatory increase in T cell proliferation in the peripheral T cell pool. After SIV infection, thymectomized animals did not have higher viral loads, greater T cell decay, or faster disease progression. We therefore conclude that peripheral destructive processes, rather than a loss of thymic output, appear to be the main causes of T cell depletion in SIV infection.
Collapse
Affiliation(s)
- Sarah Tuttleton Arron
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York, NY 10016, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Borda JT, Alvarez X, Kondova I, Aye P, Simon MA, Desrosiers RC, Lackner AA. Cell tropism of simian immunodeficiency virus in culture is not predictive of in vivo tropism or pathogenesis. THE AMERICAN JOURNAL OF PATHOLOGY 2005; 165:2111-22. [PMID: 15579453 PMCID: PMC1618703 DOI: 10.1016/s0002-9440(10)63261-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
SIVmac239/316 is a molecular clone derived from SIVmac239 that differs from the parental virus by nine amino acids in env. This virus, unlike the parental SIVmac239, is able to replicate well in alveolar macrophages in culture. We have not however, observed macrophage-associated inflammatory disease in any animal infected with SIVmac239/316. Therefore, we sought to examine the cell tropism of this virus in vivo in multiple tissues using in situ hybridization combined with immunohistochemistry and multilabel confocal microscopy for viral nucleic acid and multiple cell-type-specific markers for macrophages and T lymphocytes. Tissues examined included brain, heart, lung, lymph nodes, spleen, thymus, and small and large intestine. Matched tissues from macaques infected with the parental SIVmac239 and uninfected macaques were also examined. Many infected cells were detected in the tissues of animals infected with SIVmac239 and SIVmac239/316 although there appeared to be fewer positive cells in animals infected with SIVmac239/316. Surprisingly, in light of the cell culture observations, nearly every simian immunodeficiency virus-infected cell in animals inoculated with SIVmac239/316 was a T lymphocyte rather than a macrophage. This was true both during early infection (first 2 months) and in terminal disease. In contrast, as previously described, SIVmac239 was found in both T cells and macrophages in tissues as early as 21 days after infection. These studies indicate that during both acute and chronic SIVmac239/316 infection T lymphocytes rather than macrophages are the principal targets in vivo. These data combined with the absence of macrophage-associated lesions in SIVmac239/316-infected animals indicate that in vitro cell tropism is not predictive of in vivo tropism or disease pathogenesis.
Collapse
Affiliation(s)
- Juan T Borda
- Tulane National Primate Research Center, Tulane University, Covington, LA 70433, USA
| | | | | | | | | | | | | |
Collapse
|
30
|
Lelièvre JD, Mammano F, Arnoult D, Petit F, Grodet A, Estaquier J, Ameisen JC. A novel mechanism for HIV1-mediated bystander CD4+ T-cell death: neighboring dying cells drive the capacity of HIV1 to kill noncycling primary CD4+ T cells. Cell Death Differ 2004; 11:1017-27. [PMID: 15118766 DOI: 10.1038/sj.cdd.4401441] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
CD4+ T-cell death is a crucial feature of AIDS pathogenesis, but the mechanisms involved remain unclear. Here, we present in vitro findings that identify a novel process of HIV1 mediated killing of bystander CD4+ T cells, which does not require productive infection of these cells but depends on the presence of neighboring dying cells. X4-tropic HIV1 strains, which use CD4 and CXCR4 as receptors for cell entry, caused death of unstimulated noncycling primary CD4+ T cells only if the viruses were produced by dying, productively infected T cells, but not by living, chronically infected T cells or by living HIV1-transfected HeLa cells. Inducing cell death in HIV1-transfected HeLa cells was sufficient to obtain viruses that caused CD4+ T-cell death. The addition of supernatants from dying control cells, including primary T cells, allowed viruses produced by living HIV1-transfected cells to cause CD4+ T-cell death. CD4+ T-cell killing required HIV1 fusion and/or entry into these cells, but neither HIV1 envelope-mediated CD4 or CXCR4 signaling nor the presence of the HIV1 Nef protein in the viral particles. Supernatants from dying control cells contained CD95 ligand (CD95L), and antibody-mediated neutralization of CD95L prevented these supernatants from complementing HIV1 in inducing CD4+ T-cell death. Our in vitro findings suggest that the very extent of cell death induced in vivo during HIV1 infection by either virus cytopathic effects or immune activation may by itself provide an amplification loop in AIDS pathogenesis. More generally, they provide a paradigm for pathogen-mediated killing processes in which the extent of cell death occurring in the microenvironment might drive the capacity of the pathogen to induce further cell death.
Collapse
Affiliation(s)
- J D Lelièvre
- EMI-U 9922 INSERM/Université Paris 7, IFR02, AP-HP, Faculté de Médecine Xavier Bichat, 16 rue Henri Huchard, 75018 Paris, France.
| | | | | | | | | | | | | |
Collapse
|
31
|
Affiliation(s)
- Justin Stebbing
- Department of Immunology, Division of Investigative Science, Faculty of Medicine, Imperial College of Science, Technology and Medicine, Chelsea and Westminster Hospital, London
| | | | | |
Collapse
|
32
|
Fuller RA, Westmoreland SV, Ratai E, Greco JB, Kim JP, Lentz MR, He J, Sehgal PK, Masliah E, Halpern E, Lackner AA, González RG. A prospective longitudinal in vivo 1H MR spectroscopy study of the SIV/macaque model of neuroAIDS. BMC Neurosci 2004; 5:10. [PMID: 15070430 PMCID: PMC385227 DOI: 10.1186/1471-2202-5-10] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2003] [Accepted: 03/05/2004] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The neurological complications of HIV infection remain poorly understood. Clinically, in vivo 1H magnetic resonance spectroscopy (MRS) demonstrates brain injury caused by HIV infection even when the MRI is normal. Our goal was to undertsand the dynamics of cerebral injury by performing a longitudinal in vivo 1H MRS study of the SIV/macaque model of neuroAIDS. RESULTS Eight rhesus macaques were infected with SIVmac251 and serially imaged with MRI and 1H MRS to terminal AIDS or the endpoint of 2 years. During acute infection, there were stereotypical brain MRS changes, dominated by a significant elevation of the Cho/Cr ratio in the frontal cortex. Subsequently, brain metabolic patterns diverged between animals. There was an elevation of basal ganglia Cho/Cr four weeks post-inoculation in 2 animals that developed SIV encephalitis (p = 0.022). Metabolite ratios averaged across all 8 animals were not significantly different from baseline at any time point after 2 weeks post inoculation. However, linear regression analysis on all 8 animals revealed a positive correlation between a change in frontal lobe Cho/Cr and plasma viral load (P < 0.001, R = 0.80), and a negative correlation between NAA/Cr in the basal ganglia and the plasma viral load (P < 0.02, R = -0.73). No MRI abnormalities were detected at any time. CONCLUSIONS After infection with SIV, macaque brain metabolism changes in a complex manner that is dependent on brain region, host factors and viral load. An elevation of basal ganglia Cho/Cr 4 weeks after SIV infection may be marker of a propensity to develop SIV encephalitis. Elevations of Cho/Cr, often observed in CNS inflammation, were associated with increased plasma viral load during acute and chronic infection. Evidence of neuronal injury in the basal ganglia was associated with increased plasma viral load in the chronic stage of infection. These observations support the use of drugs capable of controlling the viral replication and trafficking of virus into the CNS, and may help explain the reduction in incidence of HIV-associated dementia in the era of HAART despite the inability of most of those drugs to effectively enter the CNS.
Collapse
Affiliation(s)
- Robert A Fuller
- Massachusetts General Hospital NMR Center and Neuroradiology Division, Harvard Medical School, Charlestown, MA, USA
| | - Susan V Westmoreland
- New England Primate Research Center, Harvard Medical School, Southborough, MA, USA
| | - Eva Ratai
- Massachusetts General Hospital NMR Center and Neuroradiology Division, Harvard Medical School, Charlestown, MA, USA
| | - Jane B Greco
- Massachusetts General Hospital NMR Center and Neuroradiology Division, Harvard Medical School, Charlestown, MA, USA
| | - John P Kim
- Massachusetts General Hospital NMR Center and Neuroradiology Division, Harvard Medical School, Charlestown, MA, USA
| | - Margaret R Lentz
- Massachusetts General Hospital NMR Center and Neuroradiology Division, Harvard Medical School, Charlestown, MA, USA
| | - Julian He
- Massachusetts General Hospital NMR Center and Neuroradiology Division, Harvard Medical School, Charlestown, MA, USA
| | - Prabhat K Sehgal
- New England Primate Research Center, Harvard Medical School, Southborough, MA, USA
| | - Eliezer Masliah
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Elkan Halpern
- Massachusetts General Hospital NMR Center and Neuroradiology Division, Harvard Medical School, Charlestown, MA, USA
| | - Andrew A Lackner
- Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, LA, USA
| | - R Gilberto González
- Massachusetts General Hospital NMR Center and Neuroradiology Division, Harvard Medical School, Charlestown, MA, USA
| |
Collapse
|
33
|
Moore JP, Kitchen SG, Pugach P, Zack JA. The CCR5 and CXCR4 coreceptors--central to understanding the transmission and pathogenesis of human immunodeficiency virus type 1 infection. AIDS Res Hum Retroviruses 2004; 20:111-26. [PMID: 15000703 DOI: 10.1089/088922204322749567] [Citation(s) in RCA: 327] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In this review, we will discuss what is known, what is suspected, and what still remains obscure about the central role played by coreceptor expression and usage in the transmission and pathogenic consequences of human immunodeficiency virus type 1 (HIV-1) infection. An emphasis will be on the HIV-1 phenotypic variants that are defined by their usage of the CCR5 or CXCR4 coreceptors, and how the different cellular tropism of these variants influences how and where HIV-1 replicates in vivo. We will also review what might happen when coreceptor antagonists are used clinically to treat HIV-1 infection.
Collapse
Affiliation(s)
- John P Moore
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10021, USA.
| | | | | | | |
Collapse
|
34
|
Abstract
In the absence of antiretroviral treatment, HIV-1 establishes a chronic, progressive infection of the human immune system that invariably, over the course of years, leads to its destruction and fatal immunodeficiency. Paradoxically, while viral replication is extensive throughout the course of infection, deterioration of conventional measures of immunity is slow, including the characteristic loss of CD4(+) T cells that is thought to play a key role in the development of immunodeficiency. This conundrum suggests that CD4(+) T cell-directed viral cytopathicity alone cannot explain the course of disease. Indeed, recent advances now indicate that HIV-1 pathogenesis is likely to result from a complex interplay between the virus and the immune system, particularly the mechanisms responsible for T cell homeostasis and regeneration. We review these data and present a model of HIV-1 pathogenesis in which the protracted loss of CD4(+) T cells results from early viral destruction of selected memory T cell populations, followed by a combination of profound increases in overall memory T cell turnover, damage to the thymus and other lymphoid tissues, and physiological limitations in peripheral CD4(+) T cell renewal.
Collapse
Affiliation(s)
- Daniel C Douek
- Human Immunology Section Vaccine Research Center, NIAID, NIH, Bethesda, Maryland 20892, USA.
| | | | | |
Collapse
|
35
|
Prins RM, Graf MR, Merchant RE, Black KL, Wheeler CJ. Thymic function and output of recent thymic emigrant T cells during intracranial glioma progression. J Neurooncol 2003; 64:45-54. [PMID: 12952285 DOI: 10.1007/bf02700019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
One of the hallmarks of patients with glioblastoma multiforme (GBM) is profound lymphopenia mostly confined to the T cell lineage. A deficiency in the production of naive T cells from the thymus could contribute to the lymphopenia seen in GBM patients. In this study we asked whether thymic function and the production of recent thymic emigrant (RTE) T cells from the thymus was influenced by intracranial (i.c.) glioma progression. We found significant thymic involution in animals with progressive i.c. gliomas. Involuted thymi from animals with progressive i.c. T9.F gliomas showed dramatic losses of CD4+ CD8+ (DP) thymocytes. Microscopic analysis complemented those findings by demonstrating a reversal of the typical cortico-medullary structure. Significant increases in apoptosis accompanied the rapid loss of viable thymocytes, which was prevented in part by adrenalectomy, suggesting a dominant role for endogenous glucocorticoids. This thymic involution was also associated with a significant decrease in peripheral RTE T cells, reflecting the diminished thymic function. Finally, we found that CD8+ RTE T cells were enriched in progressively growing T9 gliomas, which points to an immunological role for RTE's in anti-glioma immunity. Our findings may shed light on the significance of thymic function for anti-glioma immunity and the response to immunotherapeutic treatment paradigms.
Collapse
Affiliation(s)
- Robert M Prins
- Department of Anatomy and Surgery, Virginia Commonwealth University/Medical College of Virginia, Richmond, VA, USA
| | | | | | | | | |
Collapse
|
36
|
Petit F, Arnoult D, Viollet L, Estaquier J. Intrinsic and extrinsic pathways signaling during HIV-1 mediated cell death. Biochimie 2003; 85:795-811. [PMID: 14585547 DOI: 10.1016/j.biochi.2003.09.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Infection with human immunodeficiency virus (HIV) is characterized by the gradual depletion of CD4+ T lymphocytes. The incorporation of the concept of apoptosis as a rationale to explain progressive T cell depletion has led to growing research in this field during the last 10 years. In parallel, the biochemical pathways implicated in programmed cell death have been extensively studied. Thus, the influence of mitochondrial control in the two major apoptotic pathways-the extrinsic and intrinsic pathways-is now well admitted. In this review, we summarized our current knowledge of the different pathways involved in the death of T cells in the course of HIV infection.
Collapse
Affiliation(s)
- Frédéric Petit
- Unité de Physiopathologie des Infections Lentivirales, Institut Pasteur, 28, rue du Dr Roux, 75724 Paris cedex 15, France
| | | | | | | |
Collapse
|
37
|
Monceaux V, Estaquier J, Février M, Cumont MC, Rivière Y, Aubertin AM, Ameisen JC, Hurtrel B. Extensive apoptosis in lymphoid organs during primary SIV infection predicts rapid progression towards AIDS. AIDS 2003; 17:1585-96. [PMID: 12853740 DOI: 10.1097/00002030-200307250-00002] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The acute phase of HIV and SIV infections leads to a host/virus equilibrium, and accumulating evidence suggests that this early phase dictates further progression towards AIDS. To gain insight into the early events that determine rapid disease progression, we performed a longitudinal study in the SIV rhesus macaque model, allowing an in-depth analysis of the primary stage of infection. METHODS We assessed viral replication (quantification of replicating and infected cells in lymph nodes, plasma viral load), immune response (cytotoxic T lymphocyte, antibody, proliferative responses), apoptosis and cycling cells (Ki-67 labelling) on lymph nodes and blood in nine rhesus macaques infected with the pathogenic SIVmac251 isolate. RESULTS Six primates remained asymptomatic during the one year follow-up period of the study, whereas three developed AIDS within 5-6 months. During the first 2 weeks of infection, peak numbers of apoptotic cells in the lymph node T-cell areas were significantly higher in the three future rapid progressors than in the six future slow progressors, and were correlated with subsequent viraemia levels measured 6 months after infection. The numbers of infected or cycling cells in the same lymph node T-cell areas, however, only became significantly different in future rapid and slow progressors 8 weeks after infection, at the end of the primary phase. CONCLUSION Our findings identified extensive apoptosis induction in peripheral lymphoid organs as an early and predictive event that may play a crucial role in impairing the capacity of the immune system to control viral replication and progression towards disease.
Collapse
Affiliation(s)
- Valérie Monceaux
- Unité de Physiopathologie des Infections Lentivirales, Institut Pasteur, CNRS URA 1930, 28 rue du Docteur Roux, 75724 Paris, France
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Abstract
How HIV replicates and causes destruction of the thymus, and how to restore thymic function, are among the most important questions of HIV-1 pathogenesis and therapy in adult as well as pediatric patients. The thymus appears to function, albeit at reduced levels, throughout the life of adults, to respond to T cell depletion induced by HIV and to be suppressed by HIV. In this review, we summarize recent findings concerning HIV replication and pathogenesis in the human thymus, focusing on mechanistic insights gleaned from studies in the SCID-hu Thy/Liv mouse and human fetal-thymus organ culture (HF-TOC) models. First, we discuss HIV viral determinants and host factors involved in the replication of HIV in the thymus. Second, we consider evidence that both viral factors and host factors contribute to HIV-induced thymocyte depletion. We thus propose that multiple mechanisms, including depletion and suppression of progenitor cells, paracrine and direct lytic depletion of thymocytes, and altered thymocyte selection are involved in HIV-induced pathology in the thymus. With the SCID-hu Thy/Liv mouse and HF-TOC models, it will be important in the coming years to further clarify the virological, cell biological, and immunological mechanisms of HIV replication and pathogenesis in human thymus, and to correlate their significance in HIV disease progression.
Collapse
Affiliation(s)
- Eric G Meissner
- Department of Microbiology and Immunology, The Lineberger Comprehensive Cancer Center, School of Medicine, The University of North Carolina, Chapel Hill, NC 27599-7295, USA
| | | | | | | | | |
Collapse
|
39
|
Schmitt N, Chêne L, Boutolleau D, Nugeyre MT, Guillemard E, Versmisse P, Jacquemot C, Barré-Sinoussi F, Israël N. Positive regulation of CXCR4 expression and signaling by interleukin-7 in CD4+ mature thymocytes correlates with their capacity to favor human immunodeficiency X4 virus replication. J Virol 2003; 77:5784-93. [PMID: 12719571 PMCID: PMC154045 DOI: 10.1128/jvi.77.10.5784-5793.2003] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The emergence of X4 human immunodeficiency virus type 1 (HIV-1) variants in infected individuals is associated with poor prognosis. One of the possible causes of this emergence might be the selection of X4 variants in some specific tissue compartment. We demonstrate that the thymic microenvironment favors the replication of X4 variants by positively modulating the expression and signaling of CXCR4 in mature CD4(+) CD8(-) CD3(+) thymocytes. Here, we show that the interaction of thymic epithelial cells (TEC) with these thymocytes in culture induces an upregulation of CXCR4 expression. The cytokine secreted by TEC, interleukin-7 (IL-7), increases cell surface expression of CXCR4 and efficiently overcomes the downregulation induced by SDF-1 alpha, also produced by TEC. IL-7 also potentiates CXCR4 signaling, leading to actin polymerization, a process necessary for virus entry. In contrast, in intermediate CD4(+) CD8(-) CD3(-) thymocytes, the other subpopulation known to allow virus replication, TEC or IL-7 has little or no effect on CXCR4 expression and signaling. CCR5 is expressed at similarly low levels in the two thymocyte subpopulations, and neither its expression nor its signaling was modified by the cytokines tested. This positive regulation of CXCR4 by IL-7 in mature CD4(+) thymocytes correlates with their high capacity to favor X4 virus replication compared with intermediate thymocytes or peripheral blood mononuclear cells. Indeed, we observed an enrichment of X4 viruses after replication in thymocytes initially infected with a mixture of X4 (NL4-3) and R5 (NLAD8) HIV strains and after the emergence of X4 variants from an R5 primary isolate during culture in mature thymocytes.
Collapse
Affiliation(s)
- Nathalie Schmitt
- Unité de Biologie des Rétrovirus, Institut Pasteur, 75724 Paris Cedex 15, France
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Shen A, Zink MC, Mankowski JL, Chadwick K, Margolick JB, Carruth LM, Li M, Clements JE, Siliciano RF. Resting CD4+ T lymphocytes but not thymocytes provide a latent viral reservoir in a simian immunodeficiency virus-Macaca nemestrina model of human immunodeficiency virus type 1-infected patients on highly active antiretroviral therapy. J Virol 2003; 77:4938-49. [PMID: 12663799 PMCID: PMC152116 DOI: 10.1128/jvi.77.8.4938-4949.2003] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2002] [Accepted: 01/25/2003] [Indexed: 11/20/2022] Open
Abstract
Despite suppression of viremia in patients on highly active antiretroviral therapy (HAART), human immunodeficiency virus type 1 persists in a latent reservoir in the resting memory CD4(+) T lymphocytes and possibly in other reservoirs. To better understand the mechanisms of viral persistence, we established a simian immunodeficiency virus (SIV)-macaque model to mimic the clinical situation of patients on suppressive HAART and developed assays to detect latently infected cells in the SIV-macaque system. In this model, treatment of SIV-infected pig-tailed macaques (Macaca nemestrina) with the combination of 9-R-(2-phosphonomethoxypropyl)adenine (PMPA; tenofovir) and beta-2',3'-dideoxy-3'-thia-5-fluorocytidine (FTC) suppressed the levels of plasma virus to below the limit of detection (100 copies of viral RNA per ml). In treated animals, levels of viremia remained close to or below the limit of detection for up to 6 months except for an isolated "blip" of detectable viremia in each animal. Latent virus was measured in blood, spleen, lymph nodes, and thymus by several different methods. Replication-competent virus was recovered after activation of a 99.5% pure population of resting CD4(+) T lymphocytes from a lymph node of a treated animal. Integrated SIV DNA was detected in resting CD4(+) T cells from spleen, peripheral blood, and various lymph nodes including those draining the gut, the head, and the limbs. In contrast to the wide distribution of latently infected cells in peripheral lymphoid tissues, neither replication-competent virus nor integrated SIV DNA was detected in thymocytes, suggesting that thymocytes are not a major reservoir for virus in pig-tailed macaques. The results provide the first evidence for a latent viral reservoir for SIV in macaques and the most extensive survey of the distribution of latently infected cells in the host.
Collapse
Affiliation(s)
- Anding Shen
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Shimada T, Suzuki H, Motohara M, Kuwata T, Ibuki K, Ui M, Iida T, Fukumoto M, Miura T, Hayami M. Comparative histopathological studies in the early stages of acute pathogenic and nonpathogenic SHIV-infected lymphoid organs. Virology 2003; 306:334-46. [PMID: 12642106 DOI: 10.1016/s0042-6822(02)00082-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
To clarify the early pathological events in simian and human immunodeficiency chimeric virus (SHIV)-infected lymphoid organs, we examined rhesus macaques infected with an acute pathogenic SHIV (SHIV89.6P) or a nonpathogenic SHIV (NM-3rN) by sequential biopsies and serial necropsies. In the SHIV89.6P-infected monkeys, acute thymic involution as shown by increased cortical tingible-body macrophages and by neutrophilic infiltrates without follicular aggregation in the medulla began within 14 days postinoculation (dpi). Cells that were strongly positive for the virus were identified in the thymic medulla. SHIV89.6P-infected lymph nodes showed severe paracortical lymphadenitis with scattered virus-positive cells at 14 dpi and they developed paracortical depletion without the obvious follicular involution. In contrast, NM-3rN-infected monkeys showed no signs of thymic dysinvolution and the lymph nodes exhibited only follicular hyperplasia. NM-3rN-infected monkeys showed much fewer virus-positive cells in these lymphoid tissues than did SHIV89.6P-infected monkeys during the same period. These differences clearly reflect the difference in the virulence of these SHIVs.
Collapse
Affiliation(s)
- Toshihide Shimada
- Department of Pathology, Kyoto City Hospital, 604-8845, Kyoto, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Sopper S, Nierwetberg D, Halbach A, Sauer U, Scheller C, Stahl-Hennig C, Mätz-Rensing K, Schäfer F, Schneider T, ter Meulen V, Müller JG. Impact of simian immunodeficiency virus (SIV) infection on lymphocyte numbers and T-cell turnover in different organs of rhesus monkeys. Blood 2003; 101:1213-9. [PMID: 12393472 DOI: 10.1182/blood-2002-06-1644] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HIV infection leads to reduced numbers and increased turnover of CD4(+) T cells in blood. However, blood represents only 2% of the total lymphocyte pool, and information about other organs is lacking, leading to controversy about the effects of HIV infection on T-cell homeostasis. Therefore, we have determined phenotype and turnover of lymphocyte subsets in various tissues of macaques. Infection with simian immunodeficiency virus (SIV) resulted in increased proliferation rates of T cells in all organs. Despite reduced CD4 counts in blood, absolute numbers of CD4(+) T cells were increased in spleen and lymph nodes and remained stable in nonlymphoid organs such as liver, lung, bone marrow, and brain during the asymptomatic phase, indicative for an altered tissue distribution. In animals killed with first signs of AIDS, total body CD4 counts and proliferation rates had returned to control levels, whereas thymocytes were almost completely absent. Our data show that a drastically increased turnover in the early stages of HIV infection, driven by a generalized immune activation rather than a homeostatic response to CD4(+) T-cell destruction, is followed by exhaustion of the regenerative capacity of the immune system.
Collapse
Affiliation(s)
- Sieghart Sopper
- Institut für Virologie und Immunbiologie, Julius-Maximilians-Universität, Würzburg, Germany.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
|
44
|
Gurney KB, Yang OO, Wilson SB, Uittenbogaart CH. TCR gamma delta+ and CD161+ thymocytes express HIV-1 in the SCID-hu mouse, potentially contributing to immune dysfunction in HIV infection. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:5338-46. [PMID: 12391255 DOI: 10.4049/jimmunol.169.9.5338] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The vast diversity of the T cell repertoire renders the adaptive immune response capable of recognizing a broad spectrum of potential antigenic peptides. However, certain T cell rearrangements are conserved for recognition of specific pathogens, as is the case for TCRgammadelta cells. In addition, an immunoregulatory class of T cells expressing the NK receptor protein 1A (CD161) responds to nonpeptide Ags presented on the MHC-like CD1d molecule. The effect of HIV-1 infection on these specialized T cells in the thymus was studied using the SCID-hu mouse model. We were able to identify CD161-expressing CD3(+) cells but not the CD1d-restricted invariant Valpha24/Vbeta11/CD161(+) NK T cells in the thymus. A subset of TCRgammadelta cells and CD161-expressing thymocytes express CD4, CXCR4, and CCR5 during development in the thymus and are susceptible to HIV-1 infection. TCRgammadelta thymocytes were productively infectable by both X4 and R5 virus, and thymic HIV-1 infection induced depletion of CD4(+) TCRgammadelta cells. Similarly, CD4(+)CD161(+) thymocytes were depleted by thymic HIV-1 infection, leading to enrichment of CD4(-)CD161(+) thymocytes. Furthermore, compared with the general CD4-negative thymocyte population, CD4(-)CD161(+) NK T thymocytes exhibited as much as a 27-fold lower frequency of virus-expressing cells. We conclude that HIV-1 infection and/or disruption of cells important in both innate and acquired immunity may contribute to the overall immune dysfunction seen in HIV-1 disease.
Collapse
MESH Headings
- Animals
- Antigens, Surface/biosynthesis
- CD3 Complex/metabolism
- CD4 Antigens/biosynthesis
- Cell Separation
- Cells, Cultured
- HIV Infections/genetics
- HIV Infections/immunology
- HIV Infections/virology
- HIV-1/immunology
- Humans
- Immunity, Innate/genetics
- Killer Cells, Natural/cytology
- Killer Cells, Natural/immunology
- Lectins, C-Type/biosynthesis
- Mice
- Mice, SCID
- NK Cell Lectin-Like Receptor Subfamily B
- Receptors, Antigen, T-Cell, gamma-delta/biosynthesis
- Receptors, HIV/biosynthesis
- Species Specificity
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
- T-Lymphocyte Subsets/virology
- Thymus Gland/cytology
- Thymus Gland/immunology
- Thymus Gland/virology
Collapse
Affiliation(s)
- Kevin B Gurney
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, School of Medicine, 90095, USA
| | | | | | | |
Collapse
|
45
|
MacLean AG, Orandle MS, MacKey J, Williams KC, Alvarez X, Lackner AA. Characterization of an in vitro rhesus macaque blood-brain barrier. J Neuroimmunol 2002; 131:98-103. [PMID: 12458041 PMCID: PMC3635499 DOI: 10.1016/s0165-5728(02)00256-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The blood-brain barrier (BBB) has been modeled in vitro in a number of species, including rat, cow and human. Coculture of multiple cell types is required for the correct expression of tight junction proteins by microvascular brain endothelial cells (MBEC). Markers of inflammation, especially MHC-II, and cell adhesion molecules, such as VCAM-1, are not expressed on the luminal surface of the barrier under resting conditions. The rhesus macaque model has been used to study early events of HIV-neuropathogenesis in vivo, but a suitable in vitro model has not been available for detailed mechanistic studies. Here we describe an in vitro rhesus macaque blood-brain barrier that utilizes autologous MBEC and astrocytes. We believe that this model is highly relevant for examining immunological events at the blood-brain barrier and demonstrate its potential usefulness for examining early events in AIDS neuropathogenesis.
Collapse
Affiliation(s)
- Andrew G MacLean
- New England Regional Primate Research Center, Harvard Medical School, Southborough, MA 01772-9102, USA
| | | | | | | | | | | |
Collapse
|
46
|
Sodora DL, Milush JM, Ware F, Wozniakowski A, Montgomery L, McClure HM, Lackner AA, Marthas M, Hirsch V, Johnson RP, Douek DC, Koup RA. Decreased levels of recent thymic emigrants in peripheral blood of simian immunodeficiency virus-infected macaques correlate with alterations within the thymus. J Virol 2002; 76:9981-90. [PMID: 12208974 PMCID: PMC136511 DOI: 10.1128/jvi.76.19.9981-9990.2002] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The thymus is responsible for de novo production of CD4(+) and CD8(+) T cells and therefore is essential for T-cell renewal. The goal of this study was to assess the impact of simian immunodeficiency virus (SIV) infection on the production of T cells by the thymus. Levels of recent thymic emigrants within the peripheral blood were assessed through quantification of macaque T-cell receptor excision circles (TREC). Comparison of SIV-infected macaques (n = 15) to uninfected macaques (n = 23) revealed stable or increased TREC levels at 20 to 34 weeks postinfection. Further assessment of SIV-infected macaques (n = 4) determined that TREC levels decreased between 24 and 48 weeks postinfection. Through the assessment of longitudinal time points in three additional SIVmac239-infected macaques, the SIV infection was divided into two distinct phases. During phase 1 (16 to 30 weeks), TREC levels remained stable or increased within both the CD4 and CD8 T-cell populations. During phase 2 (after 16 to 30 weeks), TREC levels declined in both T-cell populations. As has been described for human immunodeficiency virus (HIV)-infected patients, this decline in TREC levels did at times correlate with an increased level of T-cell proliferation (Ki67(+) cells). However, not all TREC decreases could be attributed to increased T-cell proliferation. Further evidence for thymic dysfunction was observed directly in a SIVmac239-infected macaque that succumbed to simian AIDS at 65 weeks postinfection. The thymus of this macaque contained an increased number of memory/effector CD8(+) T cells and an increased level of apoptotic cells. In summary, reduced levels of TREC can be observed beginning at 16 to 30 weeks post-SIV infection and correlate with changes indicative of dysfunction within the thymic tissue. SIV infection of macaques will be a useful model system to elucidate the mechanisms responsible for the thymic dysfunction observed in HIV-infected patients.
Collapse
Affiliation(s)
- Donald L Sodora
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9113, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Williams K, Schwartz A, Corey S, Orandle M, Kennedy W, Thompson B, Alvarez X, Brown C, Gartner S, Lackner A. Proliferating cellular nuclear antigen expression as a marker of perivascular macrophages in simian immunodeficiency virus encephalitis. THE AMERICAN JOURNAL OF PATHOLOGY 2002; 161:575-85. [PMID: 12163382 PMCID: PMC1850726 DOI: 10.1016/s0002-9440(10)64213-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Brain perivascular macrophages are a major target of simian immunodeficiency virus (SIV) infection in rhesus macaques and HIV infection in humans. Perivascular macrophages are distinct from parenchymal microglia in their location, morphology, expression of myeloid markers, and turnover in the CNS. In contrast to parenchymal microglia, perivascular macrophages are continuously repopulated by blood monocytes, which undergo maturation to macrophages on entering the central nervous system (CNS). We studied differences in monocyte/macrophages in vivo that might account for preferential infection of perivascular macrophages by SIV. In situ hybridization for SIV and proliferating cellular nuclear antigen (PCNA) immunohistochemistry demonstrated that SIV-infected and PCNA-positive cells were predominantly found in perivascular cuffs of viremic animals and in histopathological lesions that characterize SIV encephalitis (SIVE) in animals with AIDS. Multilabel techniques including double-label immunohistochemistry and combined in situ hybridization and immunofluorescence confocal microscopy revealed numerous infected perivascular macrophages that were PCNA-positive. Outside the CNS, SIV-infected, PCNA-expressing macrophage subpopulations were found in the small intestine and lung of animals with AIDS. While PCNA is used as a marker of cell proliferation it is also strongly expressed in non-dividing cells undergoing DNA synthesis and repair. Therefore, more specific markers for cell proliferation including Ki-67, topoisomerase IIalpha, and bromodeoxyuridine (BrdU) incorporation were used which indicated that PCNA-positive cells within SIVE lesions were not proliferating. These observations are consistent with perivascular macrophages as terminally differentiated, non-dividing cells and underscores biological differences that could potentially define mechanisms of preferential, productive infection of perivascular macrophages in the rhesus macaque model of neuroAIDS. These studies suggest that within CNS and non-CNS tissues there exist subpopulations of macrophages that are SIV-infected and express PCNA.
Collapse
Affiliation(s)
- Kenneth Williams
- Department of Medicine, Harvard Medical School, Division of Viral Pathogenesis, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Orandle MS, MacLean AG, Sasseville VG, Alvarez X, Lackner AA. Enhanced expression of proinflammatory cytokines in the central nervous system is associated with neuroinvasion by simian immunodeficiency virus and the development of encephalitis. J Virol 2002; 76:5797-802. [PMID: 11992008 PMCID: PMC137036 DOI: 10.1128/jvi.76.11.5797-5802.2002] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Inflammatory cytokines are believed to play an important role in the pathogenesis of human immunodeficiency virus type 1-associated encephalitis. To examine this in the simian immunodeficiency virus (SIV)-infected macaque model of neuroAIDS, inflammatory cytokine gene expression was evaluated in the brains of macaques infected with pathogenic SIV(mac251) by reverse transcriptase PCR. Interleukin-1 beta was readily detected in the brains of all animals evaluated, regardless of infection status or duration of infection. Tumor necrosis factor alpha (TNF-alpha) and gamma interferon (IFN-gamma) transcripts were undetectable in the brains of uninfected control animals but were upregulated at 7 and 14 days postinoculation. At the terminal stage of infection, TNF-alpha and IFN-gamma transcripts were coexpressed in the brains of four of five animals with SIV encephalitis (SIVE). Within an encephalitic brain, TNF-alpha and IFN-gamma transcripts were detected in six of seven regions with histologic evidence of SIVE, suggesting a direct relationship between neuropathology and altered cytokine gene expression. With combined fluorescent in situ hybridization and immunofluorescence, TNF-alpha-expressing cells were frequently identified as CD68-positive macrophages within perivascular lesions. These observations provide evidence that cytokines produced by activated inflammatory macrophages are an important element in the pathogenesis of SIVE.
Collapse
Affiliation(s)
- Marlene S Orandle
- New England Regional Primate Research Center, Southborough, Massachusetts 01772-9102, USA
| | | | | | | | | |
Collapse
|
49
|
Abstract
The peripheral T cell pool is damaged by HIV-1 infection and can be regenerated by production of new T lymphocytes either from the thymus or from proliferation of post-thymic T cells. A critical question for AIDS patients is whether treatment with antiretroviral drugs can restore the capability to produce new T lymphocytes. The development of a new assay of thymus function in adults (the measurement of T cell receptor excision circles, TRECs), and studies of thymus biopsies in untreated and treated HIV-1-infected patients, have suggested that in select patients the thymus can regenerate on antiretroviral therapy. New strategies to overcome the thymic atrophy of aging are needed to improve thymic function in the majority of AIDS patients.
Collapse
Affiliation(s)
- Gregory D Sempowski
- Department of Medicine and the Center For AIDS Research and Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina 27710, USA.
| | | |
Collapse
|
50
|
Simard MC, Chrobak P, Kay DG, Hanna Z, Jothy S, Jolicoeur P. Expression of simian immunodeficiency virus nef in immune cells of transgenic mice leads to a severe AIDS-like disease. J Virol 2002; 76:3981-95. [PMID: 11907238 PMCID: PMC136064 DOI: 10.1128/jvi.76.8.3981-3995.2002] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In order to study the functions of simian immunodeficiency virus (SIV) Nef in vivo in a small-animal model, we constructed transgenic (Tg) mice expressing the SIV(mac)239 nef gene in the natural target cells of the virus under the control of the human CD4 gene promoter (CD4C). These CD4C/SHIV-nef(SIV) Tg mice develop a severe AIDS-like disease, with manifestations including premature death, failure to thrive or weight loss, wasting, thymic atrophy, an especially low number of peripheral CD8+ T cells as well as a low number of peripheral CD4+ T cells, diarrhea, splenomegaly, and kidney (interstitial nephritis, segmental glomerulosclerosis), lung (lymphocytic interstitial pneumonitis), and heart disease. In addition, these Tg mice fail to mount a class-switched antibody response after immunization with ovalbumin, they produce anti-DNA autoantibodies, and some of them develop Pneumocystis carinii lung infections. All these results suggest a generalized Nef-induced immunodeficiency. The low numbers of peripheral CD8+ and CD4+ T cells are likely to reflect a thymic defect and may be similar to the DiGeorge-like "thymic defect" immunophenotype described for a subgroup of human immunodeficiency virus type 1-infected children. Therefore, it appears that SIV Nef alone expressed in mice, in appropriate cell types and at sufficient levels, can elicit many of the phenotypes of simian and human AIDS. These Tg mice should be instrumental in studying the pathogenesis of SIV Nef-induced phenotypes.
Collapse
Affiliation(s)
- Marie-Chantal Simard
- Laboratory of Molecular Biology, Clinical Research Institute of Montréal, Montréal, Québec H2W 1R7, Canada
| | | | | | | | | | | |
Collapse
|