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Kenney LL, Carter EP, Gil A, Selin LK. T cells in the brain enhance neonatal mortality during peripheral LCMV infection. PLoS Pathog 2021; 17:e1009066. [PMID: 33400715 PMCID: PMC7785120 DOI: 10.1371/journal.ppat.1009066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 10/14/2020] [Indexed: 11/18/2022] Open
Abstract
In adult mice the severity of disease from viral infections is determined by the balance between the efficiency of the immune response and the magnitude of viral load. Here, the impact of this dynamic is examined in neonates. Newborns are highly susceptible to infections due to poor innate responses, lower numbers of T cells and Th2-prone immune responses. Eighty-percent of 7-day old mice, immunologically equivalent to human neonates, succumbed to extremely low doses (5 PFU) of the essentially non-lethal lymphocytic choriomeningitis virus (LCMV-Armstrong) given intraperitoneally. This increased lethality was determined to be dependent upon poor early viral control, as well as, T cells and perforin as assessed in knockout mice. By day 3, these neonatal mice had 400-fold higher viral loads as compared to adults receiving a 10,000-fold (5X104 PFU) higher dose of LCMV. The high viral load in combination with the subsequent immunological defect of partial CD8 T cell clonal exhaustion in the periphery led to viral entry and replication in the brain. Within the brain, CD8 T cells were protected from exhaustion, and thus were able to mediate lethal immunopathology. To further delineate the role of early viral control, neonatal mice were infected with Pichinde virus, a less virulent arenavirus, or LCMV was given to pups of LCMV-immune mothers. In both cases, peak viral load was at least 29-fold lower, leading to functional CD8 T cell responses and 100% survival.
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Affiliation(s)
- Laurie L. Kenney
- University of Massachusetts Medical School, Department of Pathology, Worcester, Massachusetts, United States of America
| | - Erik P. Carter
- University of Massachusetts Medical School, Department of Pathology, Worcester, Massachusetts, United States of America
| | - Anna Gil
- University of Massachusetts Medical School, Department of Pathology, Worcester, Massachusetts, United States of America
| | - Liisa K. Selin
- University of Massachusetts Medical School, Department of Pathology, Worcester, Massachusetts, United States of America
- * E-mail:
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2
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Nazerai L, Schøller AS, Rasmussen POS, Buus S, Stryhn A, Christensen JP, Thomsen AR. A New In Vivo Model to Study Protective Immunity to Zika Virus Infection in Mice With Intact Type I Interferon Signaling. Front Immunol 2018; 9:593. [PMID: 29623081 PMCID: PMC5874300 DOI: 10.3389/fimmu.2018.00593] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 03/09/2018] [Indexed: 12/12/2022] Open
Abstract
The association between recent Zika virus (ZIKV) infection and neurological complications, microcephaly in the fetus, and Guillain–Barré syndrome in adults underscores the necessity for a protective vaccine. Rational vaccine development requires an in-depth understanding of the mechanisms which could protect against infection with this virus. However, so far, such an analysis has been hampered by the absence of a suitable small animal model. Unlike the situation in humans, ZIKV only replicates effectively in the peripheral organs of mice, if type I IFN signaling is interrupted. As type I IFN also impacts the adaptive immune response, mice with such a defect are not optimal for a comprehensive immunological analysis. In this report, we show that even in wild-type (WT) mice i.c. infection with low doses of virus causes marked local virus replication and lethal encephalitis in naïve mice. Furthermore, peripheral infection of WT mice with low doses of virus induces a significant immune response, which provides long-lasting protection of WT mice from a fatal outcome of subsequent i.c. challenge. Therefore, combining peripheral priming with later i.c. challenge represents a new approach for studying the adaptive immune response to ZIKV in mice with an intact type I IFN response. In this study, we focused on the mechanisms underlying resistance to reinfection. Using a combination of adoptive transfer, antibody-based cell depletion, and gene targeting, we show that the key protective factor in type I IFN replete mice is humoral immunity. CD8 T cells are not essential in mice with preformed specific antibodies, but under conditions where initial antibody levels are low, effector CD8 T cells may play a role as a back-up system. These results have important implications for our understanding of natural immunity to ZIKV infection and for Zika vaccine design.
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Affiliation(s)
- Loulieta Nazerai
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Amalie Skak Schøller
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | | | - Søren Buus
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Anette Stryhn
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | | | - Allan Randrup Thomsen
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
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3
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Nazerai L, Bassi MR, Uddback IEM, Holst PJ, Christensen JP, Thomsen AR. Early life vaccination: Generation of adult-quality memory CD8+ T cells in infant mice using non-replicating adenoviral vectors. Sci Rep 2016; 6:38666. [PMID: 27929135 PMCID: PMC5144143 DOI: 10.1038/srep38666] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 11/14/2016] [Indexed: 12/02/2022] Open
Abstract
Intracellular pathogens represent a serious threat during early life. Importantly, even though the immune system of newborns may be characterized as developmentally immature, with a propensity to develop Th2 immunity, significant CD8+ T-cell responses may still be elicited in the context of optimal priming. Replication deficient adenoviral vectors have been demonstrated to induce potent CD8+ T-cell response in mice, primates and humans. The aim of the present study was therefore to assess whether replication-deficient adenovectors could overcome the risk of overwhelming antigen stimulation during the first period of life and provide a pertinent alternative in infant vaccinology. To address this, infant mice were vaccinated with three different adenoviral vectors and the CD8+ T-cell response after early life vaccination was explored. We assessed the frequency, polyfunctionality and in vivo cytotoxicity of the elicited memory CD8+ T cells, as well as the potential of these cells to respond to secondary infections and confer protection. We further tested the impact of maternal immunity against our replication-deficient adenoviral vector during early life vaccination. Overall, our results indicate that memory CD8+ T cells induced by adenoviral vectors in infant mice are of good quality and match those elicited in the adult host.
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Affiliation(s)
- Loulieta Nazerai
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Maria R Bassi
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Ida E M Uddback
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Peter J Holst
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Jan P Christensen
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Allan R Thomsen
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
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4
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Differential mucosal IL-10-induced immunoregulation of innate immune responses occurs in influenza infected infants/toddlers and adults. Immunol Cell Biol 2016; 95:252-260. [PMID: 27629065 DOI: 10.1038/icb.2016.91] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 08/23/2016] [Accepted: 09/07/2016] [Indexed: 01/17/2023]
Abstract
Young children (<5 years of age but especially those <2-year old) exhibit high rates of morbidity and frequently require hospitalizations due to complications from respiratory viral infections. This is also a population for which we understand less about how their unique level of immunological maturation affects their antiviral immune responses. However, we do know from prior studies that their T cells appear to apoptose in the lungs owing to limited interferon (IFN)γ autocrine signaling during infection. To begin to further understand additional limits, we utilized an infant/toddler murine model infected with influenza virus with an adult comparator. In our model, young mice exhibited lower interleukin (IL)-10+IFNγ+ co-producing CD4 T cells infiltrating the lungs that paralleled with a failed switch from an innate to adaptive immune response at the mid infection stage. Specifically, limited co-IL-10 production correlated with a lack of influenza-specific antibodies and subsequent complement receptor signaling (complement receptor type-1 related gene Y (CCRY)/p65) to the lung infiltrating CD4 T cells therefore limiting their IKAROs upregulation. Thus, limited IL-10 production appeared to diminish signaling to lung macrophages to stop accumulating late into infection. Taken together, our results suggest a novel role for complement mediated signaling in CD4 T cells with respect to IL-10 co-production. Furthermore, a subsequent failure to shift from the unfocused innate immune response to the specific adaptive responses may be a principle cause in the enhanced morbidity common in respiratory viral infection of young children.
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5
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Beyer M, Abdullah Z, Chemnitz JM, Maisel D, Sander J, Lehmann C, Thabet Y, Shinde PV, Schmidleithner L, Köhne M, Trebicka J, Schierwagen R, Hofmann A, Popov A, Lang KS, Oxenius A, Buch T, Kurts C, Heikenwalder M, Fätkenheuer G, Lang PA, Hartmann P, Knolle PA, Schultze JL. Tumor-necrosis factor impairs CD4(+) T cell-mediated immunological control in chronic viral infection. Nat Immunol 2016; 17:593-603. [PMID: 26950238 DOI: 10.1038/ni.3399] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 01/07/2016] [Indexed: 12/14/2022]
Abstract
Persistent viral infections are characterized by the simultaneous presence of chronic inflammation and T cell dysfunction. In prototypic models of chronicity--infection with human immunodeficiency virus (HIV) or lymphocytic choriomeningitis virus (LCMV)--we used transcriptome-based modeling to reveal that CD4(+) T cells were co-exposed not only to multiple inhibitory signals but also to tumor-necrosis factor (TNF). Blockade of TNF during chronic infection with LCMV abrogated the inhibitory gene-expression signature in CD4(+) T cells, including reduced expression of the inhibitory receptor PD-1, and reconstituted virus-specific immunity, which led to control of infection. Preventing signaling via the TNF receptor selectively in T cells sufficed to induce these effects. Targeted immunological interventions to disrupt the TNF-mediated link between chronic inflammation and T cell dysfunction might therefore lead to therapies to overcome persistent viral infection.
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Affiliation(s)
- Marc Beyer
- Life and Medical Sciences Bonn, Genomics &Immunoregulation, University of Bonn, Bonn, Germany.,Platform for Single Cell Genomics and Epigenomics at the German Center for Neurodegenerative Diseases and the University of Bonn, Bonn, Germany
| | - Zeinab Abdullah
- Institute of Experimental Immunology, University Hospital Bonn, Bonn, Germany
| | - Jens M Chemnitz
- Department of Internal Medicine I, University Hospital Cologne, Cologne, Germany
| | - Daniela Maisel
- Department of Internal Medicine I, University Hospital Cologne, Cologne, Germany
| | - Jil Sander
- Life and Medical Sciences Bonn, Genomics &Immunoregulation, University of Bonn, Bonn, Germany
| | - Clara Lehmann
- Department of Internal Medicine I, University Hospital Cologne, Cologne, Germany.,German Center for Infection Research, partner site Bonn-Cologne, Cologne, Germany
| | - Yasser Thabet
- Life and Medical Sciences Bonn, Genomics &Immunoregulation, University of Bonn, Bonn, Germany.,Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Prashant V Shinde
- Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Lisa Schmidleithner
- Life and Medical Sciences Bonn, Genomics &Immunoregulation, University of Bonn, Bonn, Germany
| | - Maren Köhne
- Life and Medical Sciences Bonn, Genomics &Immunoregulation, University of Bonn, Bonn, Germany
| | - Jonel Trebicka
- Department of Internal Medicine I, University Hospital Bonn, Bonn, Germany
| | - Robert Schierwagen
- Department of Internal Medicine I, University Hospital Bonn, Bonn, Germany
| | - Andrea Hofmann
- Life and Medical Sciences Bonn, Genomics &Immunoregulation, University of Bonn, Bonn, Germany.,Institute of Human Genetics, Department of Genomics, Life &Brain Center, University of Bonn, Bonn, Germany
| | - Alexey Popov
- Life and Medical Sciences Bonn, Genomics &Immunoregulation, University of Bonn, Bonn, Germany
| | - Karl S Lang
- Institute of Immunology, Faculty of Medicine, University of Duisburg-Essen, Essen, Germany
| | - Annette Oxenius
- Institute of Microbiology, Swiss Federal Institute of Technology Zürich, Zürich, Switzerland
| | - Thorsten Buch
- Institute of Laboratory Animal Science, University of Zürich, Schlieren, Switzerland
| | - Christian Kurts
- Institute of Experimental Immunology, University Hospital Bonn, Bonn, Germany
| | - Mathias Heikenwalder
- Institute of Virology, Technische Universität/Helmholtz Zentrum München, München, Germany.,Division of Chronic Inflammation and Cancer, German Cancer Research Center, Heidelberg, Germany
| | - Gerd Fätkenheuer
- Department of Internal Medicine I, University Hospital Cologne, Cologne, Germany.,German Center for Infection Research, partner site Bonn-Cologne, Cologne, Germany
| | - Philipp A Lang
- Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.,Department of Molecular Medicine II, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Pia Hartmann
- Department of Internal Medicine I, University Hospital Cologne, Cologne, Germany.,German Center for Infection Research, partner site Bonn-Cologne, Cologne, Germany.,Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Cologne, Germany
| | - Percy A Knolle
- Institute of Experimental Immunology, University Hospital Bonn, Bonn, Germany.,Institute of Molecular Immunology, Klinikum rechts der Isar, Technische Universität München, München, Germany
| | - Joachim L Schultze
- Life and Medical Sciences Bonn, Genomics &Immunoregulation, University of Bonn, Bonn, Germany.,Platform for Single Cell Genomics and Epigenomics at the German Center for Neurodegenerative Diseases and the University of Bonn, Bonn, Germany
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6
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Siefker DT, Adkins B. Rapid CD8 + Function Is Critical for Protection of Neonatal Mice from an Extracellular Bacterial Enteropathogen. Front Pediatr 2016; 4:141. [PMID: 28119902 PMCID: PMC5220481 DOI: 10.3389/fped.2016.00141] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 12/19/2016] [Indexed: 12/19/2022] Open
Abstract
Both human and murine neonates are characteristically highly susceptible to bacterial infections. However, we recently discovered that neonatal mice are surprisingly highly resistant to oral infection with Yersinia enterocolitica. This resistance was linked with activation of both innate and adaptive responses, involving innate phagocytes, CD4+ cells, and B cells. We have now extended these studies and found that CD8+ cells also contribute importantly to neonatal protection from Y. enterocolitica. Strikingly, neonatal CD8+ cells in the mesenteric lymph nodes (MLN) are rapidly mobilized, increasing in proportion, number, and IFNγ production as early as 48 h post infection. This early activation appears to be critical for protection since B2m-/- neonates are significantly more susceptible than wt neonates to primary Y. enterocolitica infection. In the absence of CD8+ cells, Y. enterocolitica rapidly disseminated to peripheral tissues. Within 48 h of infection, both the spleens and livers of B2m-/-, but not wt, neonates became heavily colonized, likely leading to their deaths from sepsis. In contrast to primary infection, CD8+ cells were dispensable for the generation of immunological memory protective against secondary infection. These results indicate that CD8+ cells in the neonatal MLN contribute importantly to protection against an extracellular bacterial enteropathogen but, notably, they appear to act during the early innate phase of the immune response.
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Affiliation(s)
- David T Siefker
- Department of Pediatrics, Le Bonheur Children's Medical Center , Memphis, TN , USA
| | - Becky Adkins
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine , Miami, FL , USA
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7
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Smith NL, Wissink E, Wang J, Pinello JF, Davenport MP, Grimson A, Rudd BD. Rapid proliferation and differentiation impairs the development of memory CD8+ T cells in early life. THE JOURNAL OF IMMUNOLOGY 2014; 193:177-84. [PMID: 24850719 DOI: 10.4049/jimmunol.1400553] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Neonates often generate incomplete immunity against intracellular pathogens, although the mechanism of this defect is poorly understood. An important question is whether the impaired development of memory CD8+ T cells in neonates is due to an immature priming environment or lymphocyte-intrinsic defects. In this article, we show that neonatal and adult CD8+ T cells adopted different fates when responding to equal amounts of stimulation in the same host. Whereas adult CD8+ T cells differentiated into a heterogeneous pool of effector and memory cells, neonatal CD8+ T cells preferentially gave rise to short-lived effector cells and exhibited a distinct gene expression profile. Surprisingly, impaired neonatal memory formation was not due to a lack of responsiveness, but instead because neonatal CD8+ T cells expanded more rapidly than adult cells and quickly became terminally differentiated. Collectively, these findings demonstrate that neonatal CD8+ T cells exhibit an imbalance in effector and memory CD8+ T cell differentiation, which impairs the formation of memory CD8+ T cells in early life.
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Affiliation(s)
- Norah L Smith
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853
| | - Erin Wissink
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853; and
| | - Jocelyn Wang
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853
| | - Jennifer F Pinello
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853
| | - Miles P Davenport
- Complex Systems in Biology Group, Centre for Vascular Research, University of New South Wales, Kensington, New South Wales 2052, Australia
| | - Andrew Grimson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853; and
| | - Brian D Rudd
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853;
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8
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Belnoue E, Fontannaz P, Rochat AF, Tougne C, Bergthaler A, Lambert PH, Pinschewer DD, Siegrist CA. Functional limitations of plasmacytoid dendritic cells limit type I interferon, T cell responses and virus control in early life. PLoS One 2013; 8:e85302. [PMID: 24376875 PMCID: PMC3871569 DOI: 10.1371/journal.pone.0085302] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 11/26/2013] [Indexed: 11/19/2022] Open
Abstract
Infant mortality from viral infection remains a major global health concern: viruses causing acute infections in immunologically mature hosts often follow a more severe course in early life, with prolonged or persistent viral replication. Similarly, the WE strain of lymphocytic choriomeningitis virus (LCMV-WE) causes acute self-limiting infection in adult mice but follows a protracted course in infant animals, in which LCMV-specific CD8⁺ T cells fail to expand and control infection. By disrupting type I IFNs signaling in adult mice or providing IFN-α supplementation to infant mice, we show here that the impaired early life T cell responses and viral control result from limited early type I IFN responses. We postulated that plasmacytoid dendritic cells (pDC), which have been identified as one major source of immediate-early IFN-I, may not exert adult-like function in vivo in the early life microenvironment. We tested this hypothesis by studying pDC functions in vivo during LCMV infection and identified a coordinated downregulation of infant pDC maturation, activation and function: despite an adult-like in vitro activation capacity of infant pDCs, the expression of the E2-2 pDC master regulator (and of critical downstream antiviral genes such as MyD88, TLR7/TLR9, NF-κB, IRF7 and IRF8) is downregulated in vivo at baseline and during LCMV infection. A similar pattern was observed in response to ssRNA polyU, a model ligand of the TLR7 viral sensor. This suggests that the limited T cell-mediated defense against early life viral infections is largely attributable to / regulated by infant pDC responses and provides incentives for novel strategies to supplement or stimulate immediate-early IFN-α responses.
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Affiliation(s)
- Elodie Belnoue
- World Health Organization Collaborating Center for Vaccinology and Neonatal Immunology, Departments of Pathology-Immunology and Pediatrics, University of Geneva, Geneva, Switzerland
| | - Paola Fontannaz
- World Health Organization Collaborating Center for Vaccinology and Neonatal Immunology, Departments of Pathology-Immunology and Pediatrics, University of Geneva, Geneva, Switzerland
| | - Anne-Françoise Rochat
- World Health Organization Collaborating Center for Vaccinology and Neonatal Immunology, Departments of Pathology-Immunology and Pediatrics, University of Geneva, Geneva, Switzerland
| | - Chantal Tougne
- World Health Organization Collaborating Center for Vaccinology and Neonatal Immunology, Departments of Pathology-Immunology and Pediatrics, University of Geneva, Geneva, Switzerland
| | - Andreas Bergthaler
- World Health Organization Collaborating Center for Vaccinology and Neonatal Immunology, Departments of Pathology-Immunology and Pediatrics, University of Geneva, Geneva, Switzerland
| | - Paul-Henri Lambert
- World Health Organization Collaborating Center for Vaccinology and Neonatal Immunology, Departments of Pathology-Immunology and Pediatrics, University of Geneva, Geneva, Switzerland
| | - Daniel D. Pinschewer
- World Health Organization Collaborating Center for Vaccinology and Neonatal Immunology, Departments of Pathology-Immunology and Pediatrics, University of Geneva, Geneva, Switzerland
| | - Claire-Anne Siegrist
- World Health Organization Collaborating Center for Vaccinology and Neonatal Immunology, Departments of Pathology-Immunology and Pediatrics, University of Geneva, Geneva, Switzerland
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9
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Prendergast AJ, Klenerman P, Goulder PJR. The impact of differential antiviral immunity in children and adults. Nat Rev Immunol 2012; 12:636-48. [PMID: 22918466 DOI: 10.1038/nri3277] [Citation(s) in RCA: 132] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The course of immune maturation has evolved to favour survival at each stage of development in early life. Fetal and neonatal immune adaptations facilitate intrauterine survival and provide early postnatal protection against extracellular pathogens, but they leave infants susceptible to intracellular pathogens such as viruses that are acquired perinatally. This Review focuses on three such pathogens--HIV, hepatitis B virus and cytomegalovirus--and relates the differential impact of these infections in infants and adults to the antiviral immunity that is generated at different ages. A better understanding of age-specific antiviral immunity may inform the development of integrated prevention, treatment and vaccine strategies to minimize the global disease burden resulting from these infections.
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Affiliation(s)
- Andrew J Prendergast
- Centre for Paediatrics, Blizard Institute, Queen Mary University of London, Newark Street, London E1 2AT, UK
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10
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Rincon MR, Oppenheimer K, Bonney EA. Selective accumulation of Th2-skewing immature erythroid cells in developing neonatal mouse spleen. Int J Biol Sci 2012; 8:719-30. [PMID: 22701342 PMCID: PMC3371569 DOI: 10.7150/ijbs.3764] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Accepted: 12/16/2011] [Indexed: 01/15/2023] Open
Abstract
Environmental factors likely regulate neonatal immunity and self-tolerance. However, evidence that the neonatal immune system is suppressed or deviated is varied depending on the antigen and the timing of antigen exposure relative to birth. These disparate findings may be related to the availability of the appropriate antigen presenting cells but also point to the possibility of homeostatic changes in non-lymphoid cells in the relevant lymphoid tissues. Here we show that, while leukocytes are the most abundant cell population present in spleen during the first 4-5 days after birth, a massive accumulation of nucleated immature erythroid population in the spleen takes places on day 6 after birth. Although the relative frequency of these immature erythorid cells slowly decreases during the development of neonates, they remain one of the most predominant populations up to three weeks of age. Importantly, we show that the immature erythroid cells from neonate spleen have the capacity to modulate the differentiation of CD4 T cells into effector cells and provide a bias towards a Th2 type instead of Th1 type. These nucleated erythroid cells can produce cytokines that participate in the Th2/Th1 balance, an important one being IL-6. Thus, the selective accumulation of immature erythroid cells in the spleen during a specific period of neonatal development may explain the apparent differences observed in the type(s) of immune responses generated in infants and neonates. These findings are potentially relevant to the better management of immune deficiency in and to the design of vaccination strategies for the young.
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Affiliation(s)
- Mercedes R Rincon
- University of Vermont College of Medicine, Department of Medicine/Immunobiology, Burlington, Vermont 05405, USA
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11
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Long-lasting protective antiviral immunity induced by passive immunotherapies requires both neutralizing and effector functions of the administered monoclonal antibody. J Virol 2010; 84:10169-81. [PMID: 20610721 DOI: 10.1128/jvi.00568-10] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Using FrCas(E) retrovirus-infected newborn mice as a model system, we have shown recently that a long-lasting antiviral immune response essential for healthy survival emerges after a short treatment with a neutralizing (667) IgG2a isotype monoclonal antibody (MAb). This suggested that the mobilization of adaptive immunity by administered MAbs is key for the success in the long term for the MAb-based passive immunotherapy of chronic viral infections. We have addressed here whether the anti-FrCas(E) protective endogenous immunity is the mere consequence of viral propagation blunting, which would simply give time to the immune system to react, and/or to actual immunomodulation by the MAb during the treatment. To this aim, we have compared viral replication, disease progression, and antiviral immune responses between different groups of infected mice: (i) mice treated with either the 667 MAb, its F(ab')(2) fragment, or an IgM (672) with epitopic specificity similar to that of 667 but displaying different effector functions, and (ii) mice receiving no treatment but infected with a low viral inoculum reproducing the initial viral expansion observed in their infected/667 MAb-treated counterparts. Our data show that the reduction of FrCas(E) propagation is insufficient on its own to induce protective immunity and support a direct immunomodulatory action of the 667 MAb. Interestingly, they also point to sequential actions of the administered MAb. In a first step, viral propagation is exclusively controlled by 667 neutralizing activity, and in a second one, this action is complemented by FcgammaR-binding-dependent mechanisms, which most likely combine infected cell cytolysis and the modulation of the antiviral endogenous immune response. Such complementary effects of administered MAbs must be taken into consideration for the improvement of future antiviral MAb-based immunotherapies.
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12
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Abstract
Newborns face complex physical and immunological changes before and after birth. Although the uterus is a sterile environment for the fetus, it also contains non-self material from the mother. Birth involves the transition from the sterile intra-uterine environment to an environment rich in microbes and requires rapid induction of appropriate responses to control these microbes. In this review we focus on the similarities and differences of human and murine neonatal DC and their reaction to various stimuli. A better understanding of the newborn immune system--in particular, the DC-T-cell interaction--will be beneficial for the development of improved strategies to prevent or treat infections in this vulnerable population and prepare the immune system to cope with allergens and tumors later in life.
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Affiliation(s)
- Fabienne Willems
- Institute for Medical Immunology, Université Libre de Bruxelles, Charleroi, Belgium
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