Loss of mandibular lymph node integrity is associated with an increase in sensitivity to HSV-1 infection in CD118-deficient mice.
TL;DR: The adoptive transfer of HSV-specific TCR transgenic CD8+ T cells into CD118−/− mice at the time of infection modestly reduced viral titers in the nervous system suggesting in addition to the generation of HSv-specific CD8 + T cells, other type I IFN-activated pathways are instrumental in controlling acute infection.
Abstract: Type I IFNs are potent antiviral cytokines that contribute to the development of the adaptive immune response. To determine the role of type I IFNs in this process in an infectious disease model, mice deficient in the type I IFN receptor (CD118(-/-)) were ocularly infected with HSV-1 and surveyed at times post infection in the nervous system and lymph node for virus and the host immune response. Virus titers were elevated in the trigeminal ganglia and brain stem with virus disseminating rapidly to the draining lymph node of CD118(-/-) mice. T cell and plasmacytoid dendritic cell infiltration into the brain stem was reduced in CD118(-/-) mice following infection, which correlated with a reduction in CXCL10 but not CXCL9 expression. In contrast, CXCL1 and CCL2 levels were up-regulated in the brainstem of CD118(-/-) mice associated with an increase in F4/80(+) macrophages. By day 5 post infection, there was a significant loss in T, NK, and plasmacytoid dendritic cell numbers in the draining lymph nodes associated with an increase in apoptotic/necrotic T cells and an appreciable lack of HSV-specific CD8(+) T cells. The adoptive transfer of HSV-specific TCR transgenic CD8(+) T cells into CD118(-/-) mice at the time of infection modestly reduced viral titers in the nervous system suggesting in addition to the generation of HSV-specific CD8(+) T cells, other type I IFN-activated pathways are instrumental in controlling acute infection.
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TL;DR: A greater understanding of the contribution of resident glial cells and infiltrating leukocytes within the CNS in response to HSV-1 invasion is necessary to identify candidate molecules as targets for therapeutic intervention to reduce unwarranted inflammation coinciding with the maintenance of the anti-viral state.
127 citations
TL;DR: It is reported that TLR signaling is expendable in herpes simplex virus (HSV)-1 containment as depicted by plaque assays of knockout mice resembling wild-type controls, and an IRF-3-dependent, IRF7- and TLR-independent innate sensor responsible for HSV containment at the site of acute infection is identified.
109 citations
TL;DR: This review illustrates examples of established brain barrier models, in which the specific reaction patterns of different viral families can be analyzed, and highlights the pathogen specific array of cytokines and chemokines involved in immunological responses in viral CNS infections.
Abstract: Neurotropic viruses can cause devastating central nervous system (CNS) infections, especially in young children and the elderly. The blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB) have been described as relevant sites of entry for specific viruses as well as for leukocytes, which are recruited during the proinflammatory response in the course of CNS infection. In this review, we illustrate examples of established brain barrier models, in which the specific reaction patterns of different viral families can be analyzed. Furthermore, we highlight the pathogen specific array of cytokines and chemokines involved in immunological responses in viral CNS infections. We discuss in detail the link between specific cytokines and chemokines and leukocyte migration profiles. The thorough understanding of the complex and interrelated inflammatory mechanisms as well as identifying universal mediators promoting CNS inflammation is essential for the development of new diagnostic and treatment strategies.
99 citations
Cites background from "Loss of mandibular lymph node integ..."
...In contrast, an increase in macrophages within the CNS of IFNAR-A1 deficient mice has been observed [138]....
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TL;DR: CCL2 expression driven by IFI-16 recognition of HSV-1 facilitates the recruitment of inflammatory monocytes into the cornea proper to control viral replication.
82 citations
TL;DR: Using magnetic resonance imaging and type I IFN receptor–deficient mouse chimeras, it is demonstrated HSV-1 gains access to the murine brain stem and subsequently brain ependymal cells, leading to enlargement of the cerebral lateral ventricle and infection of the brain parenchyma in mice.
Abstract: HSV-1 is the leading cause of sporadic viral encephalitis, with mortality rates approaching 30% despite treatment with the antiviral drug of choice, acyclovir. Permanent neurologic deficits are common in patients that survive, but the mechanism leading to this pathology is poorly understood, impeding clinical advancements in treatment to reduce CNS morbidity. Using magnetic resonance imaging and type I IFN receptor-deficient mouse chimeras, we demonstrate HSV-1 gains access to the murine brain stem and subsequently brain ependymal cells, leading to enlargement of the cerebral lateral ventricle and infection of the brain parenchyma. A similar enlargement in the lateral ventricles is found in a subpopulation of herpes simplex encephalitic patients. Associated with encephalitis is an increase in CXCL1 and CXCL10 levels in the cerebral spinal fluid, TNF-α expression in the ependymal region, and the influx of neutrophils of encephalitic mouse brains. Reduction in lateral ventricle enlargement using anti-secretory factor peptide 16 reduces mortality significantly in HSV-1-infected mice without any effect on expression of inflammatory mediators, infiltration of leukocytes, or changes in viral titer. Microglial cells but not infiltrating leukocytes or other resident glial cells or neurons are the principal source of resistance in the CNS during the first 5 d postinfection through a Toll/IL-1R domain-containing adapter inducing IFN-β-dependent, type I IFN pathway. Our results implicate lateral ventricle enlargement as a major cause of mortality in mice and speculate such an event transpires in a subpopulation of human HSV encephalitic patients.
68 citations
Cites background from "Loss of mandibular lymph node integ..."
...However, analysis of brain cortex and ependyma for cytokine and chemokine (TNF-a and CXCL10) expression by suspension array or leukocyte infiltrate (including neutrophils, macrophages, inflammatory monocytes, and NK cells) by flow cytometry revealed no significant difference in levels or cell numbers comparing peptide- to vehicle-treated mice day 7 to 8 p.i. (data not shown)....
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...We speculate CXCL10 may serve as an easily accessible predictor of inflammation severity in patients with no previous history of neuroinflammatory disease....
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...Likewise, HSE WT mice had detectable levels of IL-1a, CCL2, CXCL1, CXCL9, and CXCL10, with CXCL1 and CXCL10 expression significantly above that recovered in the CSF of non-HSE WT mice day 8 p.i. (Fig....
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...Associated with encephalitis is an increase in CXCL1 and CXCL10 levels in the cerebral spinal fluid, TNF-a expression in the ependymal region, and the influx of neutrophils of encephalitic mouse brains....
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...for CD118 mice) or the relationship between a functional type I IFN pathway and HSV-1–induced CXCL10 (34)....
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References
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TL;DR: Results indicate that viral gene expression or viral protein production is necessary for the inhibition of phosphorylation by HSV-1.
94 citations
TL;DR: Exposure to apoptotic cells rendered DCap capable of producing much more NO in response to exogenous IFN-γ than normal DC, which plays a key role in apoptotic cell-mediated immunosuppression.
Abstract: Apoptotic cells induce immunosuppression through unknown mechanisms. To identify the underlying molecular mediators, we examined how apoptotic cells induce immunoregulation by dendritic cells (DC). We found that administration of DC exposed to apoptotic cells (DC(ap)) strongly inhibited the expansion of lymphocytes in draining lymph nodes in vivo and the subsequent Ag-specific activation of these lymphocytes ex vivo. Unexpectedly, DC(ap) supported T cell activation to a similar extent as normal DC in vitro, leading to proliferation and IL-2 production, except that DC(ap) did not support T cell production of IFN-gamma. Surprisingly, when DC(ap) were cocultured with normal DC, they completely lost their ability to support T cell activation, an effect reversed by anti-IFN-gamma or inhibitors of inducible NO synthase (iNOS). As expected, exposure to apoptotic cells rendered DC(ap) capable of producing much more NO in response to exogenous IFN-gamma than normal DC. Furthermore, DC(ap) from iNOS(-/-) or IFN-gammaR1(-/-) mice were not inhibitory in vitro or in vivo. Therefore, the IFN-gamma-induced production of NO by apoptotic cell-sensitized DC plays a key role in apoptotic cell-mediated immunosuppression.
73 citations
"Loss of mandibular lymph node integ..." refers background in this paper
...Specifically, it has recently been shown that IFN- -induced NO generated in response to apoptotic cells leads to cell-mediated immunosuppression (61)....
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TL;DR: This is the first report that shows enhanced CXCL10 expression following neurotropic viral replication requires both intact TLR 9 and type I interferon signaling pathways, and is correlative with an increase in virus shedding and a reduction in neutrophil infiltration.
66 citations
TL;DR: Overall, the findings serve to identify novel transcripts that are differentially expressed in the presence or absence of IFN-αβR-mediated signaling, further elucidating interactions between the IFN and antiviral inflammatory responses in vivo.
Abstract: Pneumonia virus of mice (PVM; family Paramyxoviridae ) is a natural pathogen of rodents that reproduces important clinical features of severe respiratory syncytial virus infection in humans. As anticipated, PVM infection induces transcription of IFN antiviral response genes preferentially in wild-type over IFN-αβR gene-deleted (IFN-αβR −/− ) mice. However, we demonstrate that PVM infection results in enhanced expression of eotaxin-2 (CCL24), thymus and activation-regulated chemokine (CCL17), and the proinflammatory RNase mouse eosinophil-associated RNase (mEar) 11, and decreased expression of monocyte chemotactic protein-5, IFN-γ-inducible protein-10, and TLR-3 in lung tissue of IFN-αβR −/− mice when compared with wild type. No differential expression of chemokines MIP-1α or MIP-2 or Th2 cytokines IL-4 or IL-5 was observed. Differential expression of proinflammatory mediators was associated with distinct patterns of lung pathology. The widespread granulocytic infiltration and intra-alveolar edema observed in PVM-infected, wild-type mice are replaced with patchy, dense inflammatory foci localized to the periphery of the larger blood vessels. Bronchoalveolar lavage fluid from IFN-αβR −/− mice yielded 7- to 8-fold fewer leukocytes overall, with increased percentages of eosinophils, monocytes, and CD4 + T cells, and decreased percentage of CD8 + T cells. Differential pathology is associated with prolonged survival of the IFN-αβR −/− mice (50% survival at 10.8 ± 0.6 days vs the wild type at 9.0 ± 0.3 days; p
56 citations
"Loss of mandibular lymph node integ..." refers background in this paper
...Mice deficient in the type I IFN receptor (CD118 / ) (29) or HSV glycoprotein B (gB)T-I....
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TL;DR: It is reported that HSV-infected fibroblasts or HSV alone can inactivate T cells by profoundly inhibiting TCR signal transduction, elucidate a potentially novel method of viral immune evasion that could be exploited to better manage HSV infection, aid in vaccine design, or allow targeted manipulation of T cell function.
Abstract: T lymphocytes are an essential component of the immune response against HSV infection. We previously reported that T cells became functionally impaired or inactivated after contacting HSV-infected fibroblasts. In our current study, we investigate the mechanisms of inactivation. We report that HSV-infected fibroblasts or HSV alone can inactivate T cells by profoundly inhibiting TCR signal transduction. Inactivation requires HSV penetration into T cells but not de novo transcription or translation. In HSV-inactivated T cells stimulated through the TCR, phosphorylation of Zap70 occurs normally. However, TCR signaling is inhibited at linker for activation of T cells (LAT) and at steps distal to LAT in the TCR signal cascade including inhibition of calcium flux and inhibition of multiple MAPK. Inactivation of T cells by HSV leads to the reduced phosphorylation of LAT at tyrosine residues critical for TCR signal propagation. Treatment of T cells with tyrosine phosphatase inhibitors attenuates inactivation by HSV, and stimulus with a mitogen that bypasses LAT phosphorylation overcomes inactivation. Our findings elucidate a potentially novel method of viral immune evasion that could be exploited to better manage HSV infection, aid in vaccine design, or allow targeted manipulation of T cell function.
54 citations
"Loss of mandibular lymph node integ..." refers background in this paper
...In addition to targeting the type I IFN pathway, HSV-1 interferes with the MHC class I (9 –11) and class II (12) processing pathways, disrupts TCR signaling (13), attenuates CTL cytolytic activity (14), and induces CD4 T cell apoptosis (15)....
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