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Moulden J, Sung CYW, Brizic I, Jonjic S, Britt W. Murine Models of Central Nervous System Disease following Congenital Human Cytomegalovirus Infections. Pathogens 2021; 10:1062. [PMID: 34451526 PMCID: PMC8400215 DOI: 10.3390/pathogens10081062] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 11/17/2022] Open
Abstract
Human cytomegalovirus infection of the developing fetus is a leading cause of neurodevelopmental disorders in infants and children, leading to long-term neurological sequela in a significant number of infected children. Current understanding of the neuropathogenesis of this intrauterine infection is limited because of the complexity of this infection, which includes maternal immunological responses that are overlaid on virus replication in the CNS during neurodevelopment. Furthermore, available data from human cases are observational, and tissues from autopsy studies have been derived from only the most severe infections. Animal models of this human infection are also limited by the strict species specificity of cytomegaloviruses. However, informative models including non-human primates and small animal models have been developed. These include several different murine models of congenital HCMV infection for the study of CMV neuropathogenesis. Although individual murine models do not completely recapitulate all aspects of the human infection, each model has provided significant information that has extended current understanding of the neuropathogenesis of this human infection. This review will compare and contrast different murine models in the context of available information from human studies of CNS disease following congenital HCMV infections.
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Affiliation(s)
- Jerome Moulden
- Department of Microbiology, UAB School of Medicine, Birmingham, Al 35294, USA;
| | - Cathy Yea Won Sung
- Laboratory of Hearing Biology and Therapeutics, NIDCD, NIH, Bethesda, MD 20892, USA;
| | - Ilija Brizic
- Center for Proteomics and Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (I.B.); (S.J.)
| | - Stipan Jonjic
- Center for Proteomics and Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (I.B.); (S.J.)
| | - William Britt
- Department of Microbiology, UAB School of Medicine, Birmingham, Al 35294, USA;
- Department of Pediatrics and Neurobiology, UAB School of Medicine, Birmingham, Al 35294, USA
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2
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Fernández-Alarcón C, Meyer LE, McVoy MA, Lokensgard JR, Hu S, Benneyworth MA, Anderholm KM, Janus BC, Schleiss MR. Impairment in neurocognitive function following experimental neonatal guinea pig cytomegalovirus infection. Pediatr Res 2021; 89:838-845. [PMID: 32555536 PMCID: PMC8168912 DOI: 10.1038/s41390-020-1010-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 05/18/2020] [Accepted: 05/27/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND Cytomegalovirus (CMV) is a leading infectious cause of neurologic deficits, both in the settings of congenital and perinatal infection, but few animal models exist to study neurodevelopmental outcomes. This study examined the impact of neonatal guinea pig CMV (GPCMV) infection on spatial learning and memory in a Morris water maze (MWM) model. METHODS Newborn pups were challenged intraperitoneally (i.p.) with a pathogenic red fluorescent protein-tagged GPCMV, or sham inoculated. On days 15-19 post infection (p.i.), pups were tested in the MWM. Viral loads were measured in blood and tissue by quantitative PCR (qPCR), and brain samples collected at necropsy were examined by histology and immunohistochemistry. RESULTS Viremia (DNAemia) was detected at day 3 p.i. in 7/8 challenged animals. End-organ dissemination was observed, by qPCR, in the lung, liver, and spleen. CD4-positive (CD4+) and CD8-positive (CD8+) T cell infiltrates were present in brains of challenged animals, particularly in periventricular and hippocampal regions. Reactive gliosis and microglial nodules were observed. Statistically significant spatial learning and memory deficits were observed by MWM, particularly for total maze distance traveled (p < 0.0001). CONCLUSION Neonatal GPCMV infection in guinea pigs results in cognitive defects demonstrable by the MWM. This neonatal guinea pig challenge model can be exploited for studying antiviral interventions. IMPACT CMV impairs neonatal neurocognition and memory in the setting of postnatal infection. The MWM can be used to examine memory and learning in a guinea pig model of neonatal CMV infection. CD4+ and CD8+ T cells infiltrate the brain following neonatal CMV challenge. This article demonstrates that the MWM can be used to evaluate memory and learning after neonatal GPCMV challenge. The guinea pig can be used to examine central nervous system pathology caused by neonatal CMV infection and this attribute may facilitate the study of vaccines and antivirals.
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Affiliation(s)
| | - Lucy E Meyer
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Michael A McVoy
- Department of Pediatrics, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - James R Lokensgard
- Department of Medicine, Neurovirology Laboratory, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Shuxian Hu
- Department of Medicine, Neurovirology Laboratory, University of Minnesota Medical School, Minneapolis, MN, USA
| | | | - Kaitlyn M Anderholm
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Bradley C Janus
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Mark R Schleiss
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN, USA.
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Vincenti I, Merkler D. New advances in immune components mediating viral control in the CNS. Curr Opin Virol 2021; 47:68-78. [PMID: 33636592 DOI: 10.1016/j.coviro.2021.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/01/2021] [Accepted: 02/05/2021] [Indexed: 11/26/2022]
Abstract
Protective immune responses in the central nervous system (CNS) must act efficiently but need to be tightly controlled to avoid excessive damage to this vital organ. Under homeostatic conditions, the immune surveillance of the CNS is mediated by innate immune cells together with subsets of memory lymphocytes accumulating over lifetime. Accordingly, a wide range of immune responses can be triggered upon pathogen infection that can be associated with devastating clinical outcomes, and which most frequently are due to neurotropic viruses. Here, we discuss recent advances about our understanding of anti-viral immune responses with special emphasis on mechanisms operating in the various anatomical compartments of the CNS.
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Affiliation(s)
- Ilena Vincenti
- University of Geneva, Department of Pathology and Immunology, Geneva, Switzerland
| | - Doron Merkler
- University of Geneva, Department of Pathology and Immunology, Geneva, Switzerland; Division of Clinical Pathology, Geneva University Hospital, 1211 Geneva, Switzerland.
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Sellier Y, Marliot F, Bessières B, Stirnemann J, Encha-Razavi F, Guilleminot T, Haicheur N, Pages F, Ville Y, Leruez-Ville M. Adaptive and Innate Immune Cells in Fetal Human Cytomegalovirus-Infected Brains. Microorganisms 2020; 8:microorganisms8020176. [PMID: 31991822 PMCID: PMC7074756 DOI: 10.3390/microorganisms8020176] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 01/17/2020] [Accepted: 01/20/2020] [Indexed: 12/25/2022] Open
Abstract
Background: The understanding of the pathogenesis of cytomegalovirus (CMV)-induced fetal brain lesions is limited. We aimed to quantify adaptive and innate immune cells and CMV-infected cells in fetal brains with various degrees of brain damage. Methods: In total, 26 archived embedded fetal brains were studied, of which 21 were CMV-infected and classified in severely affected (n = 13) and moderately affected (n = 8), and 5 were uninfected controls. The respective magnitude of infected cells, immune cells (CD8+, B cells, plasma cells, NK cells, and macrophages), and expression of immune checkpoint receptors (PD-1/PD-L1 and LAG-3) were measured by immunochemistry and quantified by quantitative imaging analysis. Results: Quantities of CD8+, plasma cells, NK cells, macrophages, and HCMV+ cells and expression of PD-1/PD-L1 and LAG-3 were significantly higher in severely affected than in moderately affected brains (all p values < 0.05). A strong link between higher number of stained cells for HCMV/CD8 and PD-1 and severity of brain lesions was found by component analysis. Conclusions: The higher expression of CD8, PD-1, and LAG-3 in severely affected brains could reflect immune exhaustion of cerebral T cells. These exhausted T cells could be ineffective in controlling viral multiplication itself, leading to more severe brain lesions. The study of the functionality of brain leucocytes ex vivo is needed to confirm this hypothesis.
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Affiliation(s)
- Yann Sellier
- Service de Gynécologie-Obstétrique, Hôpital Universitaire Necker-Enfants-malades, AP-HP, 149 rue de Sèvres, 75015 Paris, France; (Y.S.); (J.S.)
- EHU 7328 PACT, 75015 Paris, France;
- Université Paris Descartes, Sorbonne Paris Cité, 75015 Paris, France; (F.M.); (B.B.); (F.E.-R.); (T.G.); (F.P.)
| | - Florence Marliot
- Université Paris Descartes, Sorbonne Paris Cité, 75015 Paris, France; (F.M.); (B.B.); (F.E.-R.); (T.G.); (F.P.)
- INSERM U872, plateforme d’Immuno-monitoring, service d’Immunologie Biologique, Hôpital Européen Georges-Pompidou, AP-HP, 75015 Paris, France;
| | - Bettina Bessières
- Université Paris Descartes, Sorbonne Paris Cité, 75015 Paris, France; (F.M.); (B.B.); (F.E.-R.); (T.G.); (F.P.)
- Service d’histologie-Embryologie-Cytogénétique Hôpital Universitaire Necker-Enfants-malades, AP-HP, 75015 Paris, France
- Institut Imagine, Université Paris Descartes (INSERM U) 1163, 75015 Paris, France
| | - Julien Stirnemann
- Service de Gynécologie-Obstétrique, Hôpital Universitaire Necker-Enfants-malades, AP-HP, 149 rue de Sèvres, 75015 Paris, France; (Y.S.); (J.S.)
- EHU 7328 PACT, 75015 Paris, France;
- Université Paris Descartes, Sorbonne Paris Cité, 75015 Paris, France; (F.M.); (B.B.); (F.E.-R.); (T.G.); (F.P.)
| | - Ferechte Encha-Razavi
- Université Paris Descartes, Sorbonne Paris Cité, 75015 Paris, France; (F.M.); (B.B.); (F.E.-R.); (T.G.); (F.P.)
- Service d’histologie-Embryologie-Cytogénétique Hôpital Universitaire Necker-Enfants-malades, AP-HP, 75015 Paris, France
| | - Tiffany Guilleminot
- Université Paris Descartes, Sorbonne Paris Cité, 75015 Paris, France; (F.M.); (B.B.); (F.E.-R.); (T.G.); (F.P.)
- Service d’histologie-Embryologie-Cytogénétique Hôpital Universitaire Necker-Enfants-malades, AP-HP, 75015 Paris, France
- Laboratoire de Virologie, Hôpital Universitaire Necker-Enfants-malades, AP-HP, Centre National de Référence, laboratoire associé Cytomégalovirus, 75015 Paris, France
| | - Nacilla Haicheur
- INSERM U872, plateforme d’Immuno-monitoring, service d’Immunologie Biologique, Hôpital Européen Georges-Pompidou, AP-HP, 75015 Paris, France;
| | - Franck Pages
- Université Paris Descartes, Sorbonne Paris Cité, 75015 Paris, France; (F.M.); (B.B.); (F.E.-R.); (T.G.); (F.P.)
- INSERM U872, plateforme d’Immuno-monitoring, service d’Immunologie Biologique, Hôpital Européen Georges-Pompidou, AP-HP, 75015 Paris, France;
| | - Yves Ville
- Service de Gynécologie-Obstétrique, Hôpital Universitaire Necker-Enfants-malades, AP-HP, 149 rue de Sèvres, 75015 Paris, France; (Y.S.); (J.S.)
- EHU 7328 PACT, 75015 Paris, France;
- Université Paris Descartes, Sorbonne Paris Cité, 75015 Paris, France; (F.M.); (B.B.); (F.E.-R.); (T.G.); (F.P.)
- Correspondence: ; Tel.: +33-1-44-49-63-32
| | - Marianne Leruez-Ville
- EHU 7328 PACT, 75015 Paris, France;
- Université Paris Descartes, Sorbonne Paris Cité, 75015 Paris, France; (F.M.); (B.B.); (F.E.-R.); (T.G.); (F.P.)
- Laboratoire de Virologie, Hôpital Universitaire Necker-Enfants-malades, AP-HP, Centre National de Référence, laboratoire associé Cytomégalovirus, 75015 Paris, France
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Chauhan P, Lokensgard JR. Glial Cell Expression of PD-L1. Int J Mol Sci 2019; 20:ijms20071677. [PMID: 30987269 PMCID: PMC6479336 DOI: 10.3390/ijms20071677] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 03/27/2019] [Accepted: 04/02/2019] [Indexed: 12/11/2022] Open
Abstract
The programmed death (PD)-1/PD-L1 pathway is a well-recognized negative immune checkpoint that results in functional inhibition of T-cells. Microglia, the brain-resident immune cells are vital for pathogen detection and initiation of neuroimmune responses. Moreover, microglial cells and astrocytes govern the activity of brain-infiltrating antiviral T-cells through upregulation of PD-L1 expression. While T-cell suppressive responses within brain are undoubtedly beneficial to the host, preventing cytotoxic damage to this vital organ, establishment of a prolonged anti-inflammatory milieu may simultaneously lead to deficiencies in viral clearance. An immune checkpoint blockade targeting the PD-1: PD-L1 (B7-H1; CD274) axis has revolutionized contemporary treatment for a variety of cancers. However, the therapeutic potential of PD1: PD-L1 blockade therapies targeting viral brain reservoirs remains to be determined. For these reasons, it is key to understand both the detrimental and protective functions of this signaling pathway within the brain. This review highlights how glial cells use PD-L1 expression to modulate T-cell effector function and limit detrimental bystander damage, while still retaining an effective defense of the brain.
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Affiliation(s)
- Priyanka Chauhan
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA.
| | - James R Lokensgard
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA.
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Brizić I, Hiršl L, Britt WJ, Krmpotić A, Jonjić S. Immune responses to congenital cytomegalovirus infection. Microbes Infect 2017; 20:543-551. [PMID: 29287989 DOI: 10.1016/j.micinf.2017.12.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 12/15/2017] [Accepted: 12/19/2017] [Indexed: 12/15/2022]
Abstract
Human cytomegalovirus (HCMV) is the most common cause of viral infection acquired in utero. Even though the infection has been studied for several decades, immune determinants important for virus control and mechanisms of long-term sequelae caused by infection are still insufficiently characterized. Animal models of congenital HCMV infection provide unique opportunity to study various aspects of human disease. In this review, we summarize current knowledge on the role of immune system in congenital CMV infection, with emphasis on lessons learned from mouse model of congenital CMV infection.
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Affiliation(s)
- Ilija Brizić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia; Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Lea Hiršl
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia; Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - William J Britt
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Pediatrics Infectious Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Astrid Krmpotić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Stipan Jonjić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia; Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia.
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7
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Abstract
The two ligands B cell-activating factor of the tumor necrosis factor family (BAFF) and a proliferation-inducing ligand (APRIL) and the three receptors BAFF receptor (BAFF-R), transmembrane activator and calcium-modulating cyclophilin ligand interactor (TACI), and B cell maturation antigen (BCMA) are members of the "BAFF system molecules." BAFF system molecules are primarily involved in B cell homeostasis. The relevance of BAFF system molecules in host responses to microbial assaults has been investigated in clinical studies and in mice deficient for each of these molecules. Many microbial products modulate the expression of these molecules. Data from clinical studies suggest a correlation between increased expression levels of BAFF system molecules and elevated B cell responses. Depending on the pathogen, heightened B cell responses may strengthen the host response or promote susceptibility. Whereas pathogen-mediated increases in the expression levels of the ligands and/or the receptors appear to promote microbial clearance, certain pathogens have evolved to ablate B cell responses by suppressing the expression of TACI and/or BAFF-R on B cells. Other than its well-established role in B cell responses, the TACI-mediated activation of macrophages is also implicated in resistance to intracellular pathogens. An improved understanding of the role that BAFF system molecules play in infection may assist in devising novel strategies for vaccine development.
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Affiliation(s)
- Jiro Sakai
- Laboratory of Bacterial Polysaccharides, Division of Bacterial Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Mustafa Akkoyunlu
- Laboratory of Bacterial Polysaccharides, Division of Bacterial Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
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Beauparlant D, Rusert P, Magnus C, Kadelka C, Weber J, Uhr T, Zagordi O, Oberle C, Duenas-Decamp MJ, Clapham PR, Metzner KJ, Günthard HF, Trkola A. Delineating CD4 dependency of HIV-1: Adaptation to infect low level CD4 expressing target cells widens cellular tropism but severely impacts on envelope functionality. PLoS Pathog 2017; 13:e1006255. [PMID: 28264054 PMCID: PMC5354460 DOI: 10.1371/journal.ppat.1006255] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 03/16/2017] [Accepted: 02/22/2017] [Indexed: 02/07/2023] Open
Abstract
A hallmark of HIV-1 infection is the continuously declining number of the virus' predominant target cells, activated CD4+ T cells. With diminishing CD4+ T cell levels, the capacity to utilize alternate cell types and receptors, including cells that express low CD4 receptor levels such as macrophages, thus becomes crucial. To explore evolutionary paths that allow HIV-1 to acquire a wider host cell range by infecting cells with lower CD4 levels, we dissected the evolution of the envelope-CD4 interaction under in vitro culture conditions that mimicked the decline of CD4high target cells, using a prototypic subtype B, R5-tropic strain. Adaptation to CD4low targets proved to severely alter envelope functions including trimer opening as indicated by a higher affinity to CD4 and loss in shielding against neutralizing antibodies. We observed a strikingly decreased infectivity on CD4high target cells, but sustained infectivity on CD4low targets, including macrophages. Intriguingly, the adaptation to CD4low targets altered the kinetic of the entry process, leading to rapid CD4 engagement and an extended transition time between CD4 and CCR5 binding during entry. This phenotype was also observed for certain central nervous system (CNS) derived macrophage-tropic viruses, highlighting that the functional perturbation we defined upon in vitro adaptation to CD4low targets occurs in vivo. Collectively, our findings suggest that CD4low adapted envelopes may exhibit severe deficiencies in entry fitness and shielding early in their evolution. Considering this, adaptation to CD4low targets may preferentially occur in a sheltered and immune-privileged environment such as the CNS to allow fitness restoring compensatory mutations to occur.
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Affiliation(s)
- David Beauparlant
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Peter Rusert
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Carsten Magnus
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Claus Kadelka
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, Zurich, Switzerland
| | - Jacqueline Weber
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Therese Uhr
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Osvaldo Zagordi
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Corinna Oberle
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Maria J. Duenas-Decamp
- Program in Molecular Medicine, Biotech II, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Paul R. Clapham
- Program in Molecular Medicine, Biotech II, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Karin J. Metzner
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, Zurich, Switzerland
| | - Huldrych F. Günthard
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, Zurich, Switzerland
| | - Alexandra Trkola
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
- * E-mail:
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Chauhan P, Hu S, Sheng WS, Prasad S, Lokensgard JR. Modulation of Microglial Cell Fcγ Receptor Expression Following Viral Brain Infection. Sci Rep 2017; 7:41889. [PMID: 28165503 PMCID: PMC5292951 DOI: 10.1038/srep41889] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 01/03/2017] [Indexed: 12/22/2022] Open
Abstract
Fcγ receptors (FcγRs) for IgG couple innate and adaptive immunity through activation of effector cells by antigen-antibody complexes. We investigated relative levels of activating and inhibitory FcγRs on brain-resident microglia following murine cytomegalovirus (MCMV) infection. Flow cytometric analysis of microglial cells obtained from infected brain tissue demonstrated that activating FcγRs were expressed maximally at 5 d post-infection (dpi), while the inhibitory receptor (FcγRIIB) remained highly elevated during both acute and chronic phases of infection. The highly induced expression of activating FcγRIV during the acute phase of infection was also noteworthy. Furthermore, in vitro analysis using cultured primary microglia demonstrated the role of interferon (IFN)γ and interleukin (IL)-4 in polarizing these cells towards a M1 or M2 phenotype, respectively. Microglial cell-polarization correlated with maximal expression of either FcγRIV or FcγRIIB following stimulation with IFNγ or IL-4, respectively. Finally, we observed a significant delay in polarization of microglia towards an M2 phenotype in the absence of FcγRs in MCMV-infected Fcer1g and FcgR2b knockout mice. These studies demonstrate that neuro-inflammation following viral infection increases expression of activating FcγRs on M1-polarized microglia. In contrast, expression of the inhibitory FcγRIIB receptor promotes M2-polarization in order to shut-down deleterious immune responses and limit bystander brain damage.
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Affiliation(s)
- Priyanka Chauhan
- Neurovirology Laboratory, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Shuxian Hu
- Neurovirology Laboratory, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Wen S Sheng
- Neurovirology Laboratory, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Sujata Prasad
- Neurovirology Laboratory, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - James R Lokensgard
- Neurovirology Laboratory, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA
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Lokensgard JR, Mutnal MB, Prasad S, Sheng W, Hu S. Glial cell activation, recruitment, and survival of B-lineage cells following MCMV brain infection. J Neuroinflammation 2016; 13:114. [PMID: 27207308 PMCID: PMC4874004 DOI: 10.1186/s12974-016-0582-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 05/13/2016] [Indexed: 12/23/2022] Open
Abstract
Background Chemokines produced by reactive glia drive migration of immune cells and previous studies from our laboratory have demonstrated that CD19+ B cells infiltrate the brain. In this study, in vivo and in vitro experiments investigated the role of reactive glial cells in recruitment and survival of B-lineage cells in response to (murine cytomegalovirus) MCMV infection. Methods Flow cytometric analysis was used to assess chemokine receptor expression on brain-infiltrating B cells. Real-time RT-PCR and ELISA were used to measure chemokine levels. Dual-immunohistochemical staining was used to co-localize chemokine production by reactive glia. Primary glial cell cultures and migration assays were used to examine chemokine-mediated recruitment. Astrocyte: B cell co-cultures were used to investigate survival and proliferation. Results The chemokine receptors CXCR3, CXCR5, CCR5, and CCR7 were detected on CD19+ cells isolated from the brain during MCMV infection. In particular, CXCR3 was found to be elevated on an increasing number of cells over the time course of infection, and it was the primary chemokine receptor expressed at 60 days post infection Quite different expression kinetics were observed for CXCR5, CCR5, and CCR7, which were elevated on the highest number of cells early during infection and decreased by 14, 30, and 60 days post infection Correspondingly, elevated levels of CXCL9, CXCL10, and CXCL13, as well as CCL5, were found within the brains of infected animals, and only low levels of CCL3 and CCL19 were detected. Differential expression of CXCL9/CXCL10 and CXCL13 between microglia and astrocytes was apparent, and B cells moved towards supernatants from MCMV-infected microglia, but not astrocytes. Pretreatment with neutralizing Abs to CXCL9 and CXCL10 inhibited this migration. In contrast, neutralizing Abs to the ligand of CXCR5 (i.e., CXCL13) did not significantly block chemotaxis. Proliferation of brain-infiltrating B cells was detected at 7 days post infection and persisted through the latest time tested (60 days post infection). Finally, astrocytes produce BAFF (B cell activating factor of the TNF family) and promote proliferation of B cells via cell-to-cell contact. Conclusions CXCR3 is the primary chemokine receptor on CD19+ B cells persisting within the brain, and migration to microglial cell supernatants is mediated through this receptor. Correspondingly, microglial cells produce CXCL9 and CXCL10, but not CXCL13. Reactive astrocytes promote B cell proliferation.
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Affiliation(s)
- James R Lokensgard
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, 3-220 LRB/MTRF, 2001 6th Street S.E., Minneapolis, MN, 55455, USA.
| | - Manohar B Mutnal
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, 3-220 LRB/MTRF, 2001 6th Street S.E., Minneapolis, MN, 55455, USA
| | - Sujata Prasad
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, 3-220 LRB/MTRF, 2001 6th Street S.E., Minneapolis, MN, 55455, USA
| | - Wen Sheng
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, 3-220 LRB/MTRF, 2001 6th Street S.E., Minneapolis, MN, 55455, USA
| | - Shuxian Hu
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, 3-220 LRB/MTRF, 2001 6th Street S.E., Minneapolis, MN, 55455, USA
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Prasad S, Hu S, Sheng WS, Singh A, Lokensgard JR. Tregs Modulate Lymphocyte Proliferation, Activation, and Resident-Memory T-Cell Accumulation within the Brain during MCMV Infection. PLoS One 2015; 10:e0145457. [PMID: 26720146 PMCID: PMC4697843 DOI: 10.1371/journal.pone.0145457] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 12/03/2015] [Indexed: 11/25/2022] Open
Abstract
Accumulation and retention of regulatory T-cells (Tregs) has been reported within post viral-encephalitic brains, however, the full extent to which these cells modulate neuroinflammation is yet to be elucidated. Here, we used Foxp3-DTR (diphtheria toxin receptor) knock-in transgenic mice, which upon administration of low dose diphtheria toxin (DTx) results in specific deletion of Tregs. We investigated the proliferation status of various immune cell subtypes within inflamed central nervous system (CNS) tissue. Depletion of Tregs resulted in increased proliferation of both CD8+ and CD4+ T-cell subsets within the brain at 14 d post infection (dpi) when compared to Treg-sufficient animals. At 30 dpi, while proliferation of CD8+ T-cells was controlled within brains of both Treg-depleted and undepleted mice, proliferation of CD4+ T-cells remained significantly enhanced with DTx-treatment. Previous studies have demonstrated that Treg numbers within the brain rebound following DTx treatment to even higher numbers than in untreated animals. Despite this rebound, CD8+ and CD4+ T-cells proliferated at a higher rate when compared to that of Treg-sufficient mice, thus maintaining sustained neuroinflammation. Furthermore, at 30 dpi we found the majority of CD8+ T-cells were CD127hi KLRG1- indicating that the cells were long lived memory precursor cells. These cells showed marked elevation of CD103 expression, a marker of tissue resident-memory T-cells (TRM) in the CNS, in untreated animals when compared to DTx-treated animals suggesting that generation of TRM is impaired upon Treg depletion. Moreover, the effector function of TRM as indicated by granzyme B production in response to peptide re-stimulation was found to be more potent in Treg-sufficient animals. Taken together, our findings demonstrate that Tregs limit neuroinflammatory responses to viral infection by controlling cell proliferation and may direct a larger proportion of lymphocytes within the brain to be maintained as TRM cells.
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Affiliation(s)
- Sujata Prasad
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, 55455, United States of America
| | - Shuxian Hu
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, 55455, United States of America
| | - Wen S. Sheng
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, 55455, United States of America
| | - Amar Singh
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, 55455, United States of America
| | - James R. Lokensgard
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, 55455, United States of America
- * E-mail:
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12
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Ikuta K, Ogawa H, Hashimoto H, Okano W, Tani A, Sato E, Kosugi I, Kobayashi T, Omori K, Suzutani T. Restricted infection of murine cytomegalovirus (MCMV) in neonatal mice with MCMV-induced sensorineural hearing loss. J Clin Virol 2015. [PMID: 26209396 DOI: 10.1016/j.jcv.2015.06.083] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND Congenital infection with human Cytomegalovirus (HCMV) is known to be a causative agent of sensorineural hearing loss (SNHL). OBJECTIVES To clarify the nongenetic etiology of SNHL by identifying the Cytomegalovirus (CMV)-infected region in the cochleae. STUDY DESIGN We established an animal model of SNHL by injecting neonatal Balb/c mice with intracerebral murine Cytomegalovirus (MCMV) within 24h after delivery. RESULTS At 3 weeks of age, unilateral and bilateral SNHL were observed in 24% (5/21) and 29% (6/21) of the mice, respectively. SNHL thereafter progressed, with 79% of mice developing bilateral SNHL by 6 weeks of age. MCMV antigens and DNA were detected in the spiral ganglion, and cells surrounding the meninges and scala tympani at 1 week of age. However, both MCMV antigens and DNA had completely disappeared by 2 weeks of age. It is possible that the MCMV reached the spiral ganglion via cerebrospinal fluid as the result of meningitis, as the stria vascularis was found to be MCMV antigen negative. Myosin VI expression in the outer hair cells was lost at 3 weeks of age. MCMV and myosin VI expression disappeared before and during SNHL progression, respectively. CONCLUSIONS There was a definite lag time between the period in which MCMV antigens/DNA-positive cells were observed and that in which SNHL developed and myosin VI-negative hair cells were observed. Further study is needed to explore the role of MCMV in the loss of myosin VI expression in the outer hair cells.
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Affiliation(s)
- Kazufumi Ikuta
- Department of Microbiology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Hiroshi Ogawa
- Department of Otolaryngology, Fukushima Medical University School of Medicine, Fukushima, Japan; Department of Otolaryngology, Aizu Medical Center, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Hiromi Hashimoto
- Department of Microbiology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Wataru Okano
- Department of Otolaryngology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Akiko Tani
- Department of Otolaryngology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Etsuko Sato
- Department of Otolaryngology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Isao Kosugi
- Department of Pathology II, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Takahiro Kobayashi
- Department of Microbiology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Koichi Omori
- Department of Otolaryngology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Tatsuo Suzutani
- Department of Microbiology, Fukushima Medical University School of Medicine, Fukushima, Japan
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13
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Lokensgard JR, Schachtele SJ, Mutnal MB, Sheng WS, Prasad S, Hu S. Chronic reactive gliosis following regulatory T cell depletion during acute MCMV encephalitis. Glia 2015; 63:1982-1996. [PMID: 26041050 DOI: 10.1002/glia.22868] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 05/12/2015] [Indexed: 12/21/2022]
Abstract
Long-term, persistent central nervous system inflammation is commonly seen following brain infection. Using a murine model of viral encephalitis (murine cytomegalovirus, MCMV) we have previously shown that post-encephalitic brains are maintained in an inflammatory state consisting of glial cell reactivity, retention of brain-infiltrating tissue-resident memory CD8+ T-cells, and long-term persistence of antibody-producing cells of the B-lineage. Here, we report that this neuroinflammation occurs concomitantly with accumulation and retention of immunosuppressive regulatory T-cells (Tregs), and is exacerbated following their ablation. However, the extent to which these Tregs function to control neuroimmune activation following MCMV encephalitis is unknown. In this study, we used Foxp3-diphtheria toxin receptor-GFP (Foxp3-DTR-GFP) transgenic mice, which upon administration of low-dose diphtheria toxin (DTx) results in the specific depletion of Tregs, to investigate their function. We found treatment with DTx during the acute phase of viral brain infection (0-4 dpi) resulted in depletion of Tregs from the brain, exacerbation of encephalitis (i.e., increased presence of CD4+ and CD8+ T-cells), and chronic reactive phenotypes of resident glial cells (i.e., elevated MHC Class II as well as PD-L1 levels, sustained microgliosis, and increased glial fibrillary acidic protein (GFAP) expression on astrocytes) versus untreated, infected animals. This chronic proinflammatory environment was associated with reduced cognitive performance in spatial learning and memory tasks (Barnes Maze) by convalescent animals. These data demonstrate that chronic glial cell activation, unremitting post-encephalitic neuroinflammation, and its associated long-term neurological sequelae in response to viral brain infection are modulated by the immunoregulatory properties of Tregs. GLIA 2015;63:1982-1996.
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Affiliation(s)
- James R Lokensgard
- Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Scott J Schachtele
- Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Manohar B Mutnal
- Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Wen S Sheng
- Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Sujata Prasad
- Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Shuxian Hu
- Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
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14
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Coleman SM, McGregor A. A bright future for bioluminescent imaging in viral research. Future Virol 2015; 10:169-183. [PMID: 26413138 DOI: 10.2217/fvl.14.96] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Bioluminescence imaging (BLI) has emerged as a powerful tool in the study of animal models of viral disease. BLI enables real-time in vivo study of viral infection, host immune response and the efficacy of intervention strategies. Substrate dependent light emitting luciferase enzyme when incorporated into a virus as a reporter gene enables detection of bioluminescence from infected cells using sensitive charge-coupled device (CCD) camera systems. Advantages of BLI include low background, real-time tracking of infection in the same animal and reduction in the requirement for larger animal numbers. Transgenic luciferase-tagged mice enable the use of pre-existing nontagged viruses in BLI studies. Continued development in luciferase reporter genes, substrates, transgenic animals and imaging systems will greatly enhance future BLI strategies in viral research.
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Affiliation(s)
- Stewart M Coleman
- Health Science Center, Department of Microbial Pathogenesis & Immunology, Texas A&M University, 407 Reynolds Medical Building, College Station, TX 77843-1114, USA
| | - Alistair McGregor
- Health Science Center, Department of Microbial Pathogenesis & Immunology, Texas A&M University, 407 Reynolds Medical Building, College Station, TX 77843-1114, USA
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15
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Mutnal MB, Hu S, Schachtele SJ, Lokensgard JR. Infiltrating regulatory B cells control neuroinflammation following viral brain infection. THE JOURNAL OF IMMUNOLOGY 2014; 193:6070-80. [PMID: 25385825 DOI: 10.4049/jimmunol.1400654] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Previous studies have demonstrated the existence of a subset of B lymphocytes, regulatory B cells (Bregs), which modulate immune function. In this study, in vivo and in vitro experiments were undertaken to elucidate the role of these Bregs in controlling neuroinflammation following viral brain infection. We used multicolor flow cytometry to phenotype lymphocyte subpopulations infiltrating the brain, along with in vitro cocultures to assess their anti-inflammatory and immunoregulatory roles. This distinctive subset of CD19(+)CD1d(hi)CD5(+) B cells was found to infiltrate the brains of chronically infected animals, reaching highest levels at the latest time point tested (30 d postinfection). B cell-deficient Jh(-/-) mice were found to develop exacerbated neuroimmune responses as measured by enhanced accumulation and/or retention of CD8(+) T cells within the brain, as well as increased levels of microglial activation (MHC class II). Conversely, levels of Foxp3(+) regulatory T cells were found to be significantly lower in Jh(-/-) mice when compared with wild-type (Wt) animals. Further experiments showed that in vitro-generated IL-10-secreting Bregs (B10) were able to inhibit cytokine responses from microglia following stimulation with viral Ags. These in vitro-generated B10 cells were also found to promote proliferation of regulatory T cells in coculture studies. Finally, gain-of-function experiments demonstrated that reconstitution of Wt B cells into Jh(-/-) mice restored neuroimmune responses to levels exhibited by infected Wt mice. Taken together, these results demonstrate that Bregs modulate T lymphocyte as well as microglial cell responses within the infected brain and promote CD4(+)Foxp3(+) T cell proliferation in vitro.
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Affiliation(s)
- Manohar B Mutnal
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, MN 55455
| | - Shuxian Hu
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, MN 55455
| | - Scott J Schachtele
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, MN 55455
| | - James R Lokensgard
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, MN 55455
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Activated CD8+ T lymphocytes inhibit neural stem/progenitor cell proliferation: role of interferon-gamma. PLoS One 2014; 9:e105219. [PMID: 25133679 PMCID: PMC4136865 DOI: 10.1371/journal.pone.0105219] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 07/21/2014] [Indexed: 12/03/2022] Open
Abstract
The ability of neural stem/progenitor cells (NSCs) to self-renew, migrate to damaged sites, and differentiate into neurons has renewed interest in using them in therapies for neurodegenerative disorders. Neurological diseases, including viral infections of the brain, are often accompanied by chronic inflammation, whose impact on NSC function remains unexplored. We have previously shown that chronic neuroinflammation, a hallmark of experimental herpes simplex encephalitis (HSE) in mice, is dominated by brain-infiltrating activated CD8 T-cells. In the present study, activated CD8 lymphocytes were found to suppress NSC proliferation profoundly. Luciferase positive (luc+) NSCs co-cultured with activated, MHC-matched, CD8+ lymphocytes (luc−) showed two- to five-fold lower luminescence than co-cultures with un-stimulated lymphocytes. On the other hand, similarly activated CD4+ lymphocytes did not suppress NSC growth. This differential lymphocyte effect on proliferation was confirmed by decreased BrdU uptake by NSC cultured with activated CD8 T-cells. Interestingly, neutralizing antibodies to interferon-gamma (IFN-γ) reversed the impact of CD8 lymphocytes on NSCs. Antibodies specific to the IFN-γ receptor-1 subunit complex abrogated the inhibitory effects of both CD8 lymphocytes and IFN-γ, indicating that the inhibitory effect of these cells was mediated by IFN-γ in a receptor-specific manner. In addition, activated CD8 lymphocytes decreased levels of nestin and Sox2 expression in NSCs while increasing GFAP expression, suggesting possible induction of an altered differentiation state. Furthermore, NSCs obtained from IFN-γ receptor-1 knock-out embryos were refractory to the inhibitory effects of activated CD8+ T lymphocytes on cell proliferation and Sox2 expression. Taken together, the studies presented here demonstrate a role for activated CD8 T-cells in regulating NSC function mediated through the production of IFN-γ. This cytokine may influence neuro-restorative processes and ultimately contribute to the long-term sequelae commonly seen following herpes encephalitis.
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Slavuljica I, Kveštak D, Huszthy PC, Kosmac K, Britt WJ, Jonjić S. Immunobiology of congenital cytomegalovirus infection of the central nervous system—the murine cytomegalovirus model. Cell Mol Immunol 2014; 12:180-91. [PMID: 25042632 DOI: 10.1038/cmi.2014.51] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 06/02/2014] [Indexed: 02/05/2023] Open
Abstract
Congenital human cytomegalovirus infection is a leading infectious cause of long-term neurodevelopmental sequelae, including mental retardation and hearing defects. Strict species specificity of cytomegaloviruses has restricted the scope of studies of cytomegalovirus infection in animal models. To investigate the pathogenesis of congenital human cytomegalovirus infection, we developed a mouse cytomegalovirus model that recapitulates the major characteristics of central nervous system infection in human infants, including the route of neuroinvasion and neuropathological findings. Following intraperitoneal inoculation of newborn animals with mouse cytomegalovirus, the virus disseminates to the central nervous system during high-level viremia and replicates in the brain parenchyma, resulting in a focal but widespread, non-necrotizing encephalitis. Central nervous system infection is coupled with the recruitment of resident and peripheral immune cells as well as the expression of a large number of pro-inflammatory cytokines. Although infiltration of cellular constituents of the innate immune response characterizes the early immune response in the central nervous system, resolution of productive infection requires virus-specific CD8(+) T cells. Perinatal mouse cytomegalovirus infection results in profoundly altered postnatal development of the mouse central nervous system and long-term motor and sensory disabilities. Based on an enhanced understanding of the pathogenesis of this infection, prospects for novel intervention strategies aimed to improve the outcome of congenital human cytomegalovirus infection are proposed.
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Affiliation(s)
- Irena Slavuljica
- 1] Department of Histology and Embryology, School of Medicine, University of Rijeka, Rijeka, Croatia [2] Department of Infectious Diseases, School of Medicine, University of Rijeka, Rijeka, Croatia
| | - Daria Kveštak
- Department of Histology and Embryology, School of Medicine, University of Rijeka, Rijeka, Croatia
| | - Peter Csaba Huszthy
- 1] Department of Histology and Embryology, School of Medicine, University of Rijeka, Rijeka, Croatia [2] Department of Immunology, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Kate Kosmac
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - William J Britt
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Stipan Jonjić
- Department of Histology and Embryology, School of Medicine, University of Rijeka, Rijeka, Croatia
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Schachtele SJ, Hu S, Sheng WS, Mutnal MB, Lokensgard JR. Glial cells suppress postencephalitic CD8+ T lymphocytes through PD-L1. Glia 2014; 62:1582-94. [PMID: 24890099 PMCID: PMC4141010 DOI: 10.1002/glia.22701] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Revised: 04/30/2014] [Accepted: 05/15/2014] [Indexed: 01/06/2023]
Abstract
Engagement of the programmed death (PD)−1 receptor on activated cells by its ligand (PD‐L1) is a mechanism for suppression of activated T‐lymphocytes. Microglia, the resident inflammatory cells of the brain, are important for pathogen detection and initiation of innate immunity, however, a novel role for these cells as immune regulators has also emerged. PD‐L1 on microglia has been shown to negatively regulate T‐cell activation in models of multiple sclerosis and acute viral encephalitis. In this study, we investigated the role of glial cell PD‐L1 in controlling encephalitogenic CD8+ T‐lymphocytes, which infiltrate the brain to manage viral infection, but remain to produce chronic neuroinflammation. Using a model of chronic neuroinflammation following murine cytomegalovirus (MCMV)‐induced encephalitis, we found that CD8+ T‐cells persisting within the brain expressed PD‐1. Conversely, activated microglia expressed PD‐L1. In vitro, primary murine microglia, which express low basal levels of PD‐L1, upregulated the co‐inhibitory ligand on IFN‐γ‐treatment. Blockade of the PD‐1: PD‐L1 pathway in microglial: CD8+ T‐cell co‐cultures increased T‐cell IFN‐γ and interleukin (IL)−2 production. We observed a similar phenomenon following blockade of this co‐inhibitory pathway in astrocyte: CD8+ T‐cell co‐cultures. Using ex vivo cultures of brain leukocytes, including microglia and CD8+ T‐cells, obtained from mice with MCMV‐induced chronic neuroinflammation, we found that neutralization of either PD‐1 or PD‐L1 increased IFN‐γ production from virus‐specific CD8+ T‐cells stimulated with MCMV IE1168–176 peptide. These data demonstrate that microglia and astrocytes control antiviral T‐cell responses and suggest a therapeutic potential of PD1: PD‐L1 modulation to manage the deleterious consequences of uncontrolled neuroinflammation. GLIA 2014;62:1582–1594 Microglia and astrocytes exert regulatory control over T‐cells during chronic neuroinflammation following viral brain infection. Post-encephalitic glial cells express PD‐L1 and suppress persistent CD8 T‐cells via the PD‐1: PD‐L1 inhibitory pathway.
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Affiliation(s)
- Scott J Schachtele
- Department of Medicine, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota, McGuire Translational Research Facility, Minneapolis, Minnesota
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