CD8+ T cells in the central nervous system of mice with herpes simplex infection are highly activated and express high levels of CCR5 and CXCR3.

Herpes simplex virus type 2 (HSV-2) is a neurotropic virus that can cause meningitis, an inflammation of the meninges in the central nervous system. T cells are key players in viral clearance, and these cells migrate from peripheral blood into the central nervous system upon infection. Several factors contribute to T cell migration, including the expression of chemokines in the inflamed tissue that attract T cells through their expression of chemokine receptors. Here we investigated CD8+ T cell profile in the spinal cord in a mouse model of herpes simplex virus type 2 neuroinflammation. Mice were infected with HSV-2 and sacrificed when showing signs of neuroinflammation. Cells and/or tissue from spinal cord, spleen, and blood were analyzed for expression of activation markers, chemokine receptors, and chemokines. High numbers of CD8+ T cells were present in the spinal cord following genital HSV-2-infection. CD8+ T cells were highly activated and HSV-2 glycoprotein B -specific effector cells, some of which showed signs of recent degranulation. They also expressed high levels of many chemokine receptors, in particular CCR2, CCR4, CCR5, and CXCR3. Investigating corresponding receptor ligands in spinal cord tissue revealed markedly increased expression of the cognate ligands CCL2, CCL5, CCL8, CCL12, and CXCL10. This study shows that during herpesvirus neuroinflammation anti-viral CD8+ T cells accumulate in the CNS. CD8+ T cells in the CNS also express chemotactic receptors cognate to the chemotactic gradients in the spinal cord. This indicates that anti-viral CD8+ T cells may migrate to infected areas in the spinal cord during herpesvirus neuroinflammation in response to chemotactic gradients.

Cerebrospinal fluid biomarkers of brain injury, inflammation and synaptic autoimmunity predict long-term neurocognitive outcome in herpes simplex encephalitis.

OBJECTIVES: The aim was to investigate the correlation between biomarkers of brain injury and long-term neurocognitive outcome, and the interplay with intrathecal inflammation and neuronal autoimmunity, in patients with herpes simplex encephalitis (HSE). METHODS: A total of 53 adult/adolescent HSE patients were included from a prospective cohort in a randomized placebo-controlled trial investigating the effect of a 3-month follow-up treatment with valaciclovir. Study subjects underwent repeated serum/cerebrospinal fluid (CSF) sampling and brain magnetic resonance imaging in the first 3 months along with cognitive assessment using the Mattis Dementia Rating Scale (MDRS) at 24 months. CSF samples were analysed for biomarkers of brain injury, inflammation and synaptic autoimmunity. The predefined primary analysis was the correlation between peak CSF neurofilament protein (NFL), a biomarker of neuronal damage, and MDRS at 24 months. RESULTS: Impaired cognitive performance significantly correlated with NFL levels (rho = -0.36, p = 0.020). Development of IgG anti-N-methyl-D-aspartate receptor (NDMAR) antibodies was associated with a broad and prolonged proinflammatory CSF response. In a linear regression model, lower MDRS at 24 months was associated with previous development of IgG anti-N-methyl-D-aspartate receptor (NMDAR) (beta = -0.6249, p = 0.024) and age (z-score beta = -0.2784, p = 0.024), but not CSF NFL, which however significantly correlated with subsequent NMDAR autoimmunization (p = 0.006). DISCUSSION: Our findings show that NFL levels are predictive of long-term neurocognitive outcome in HSE, and suggest a causative chain of events where brain tissue damage increases the risk of NMDAR autoimmunisation and subsequent prolongation of CSF inflammation. The data provides guidance for a future intervention study of immunosuppressive therapy administered in the recovery phase of HSE.

Chemokines and matrix metalloproteinases in cerebrospinal fluid of patients with central nervous system complications caused by varicella-zoster virus.

BACKGROUND: Varicella-zoster virus (VZV) is a common viral agent causing central nervous system (CNS) infections including encephalitis, meningitis, and Ramsay Hunt syndrome. Neurological complications occur frequently despite antiviral treatment. Matrix metalloproteinases (MMPs) and cytokines are involved in the neuroinflammatory response during CNS infection. Their role in VZV CNS infections and how they differ between different CNS entities caused by VZV are poorly investigated. METHODS: We analyzed the levels of 30 chemokines and 9 MMPs in cerebrospinal fluid (CSF) and serum from 66 patients with VZV CNS infections diagnosed by detection of VZV DNA in CSF and concomitant neurological symptoms and compared with a control group (n = 24). RESULTS: Levels of CCL19, CXCL8, CXCL9, and CXCL10 were significantly increased and surpassing the levels in serum when analyzing all patients with VZV CNS infections whereas CXCL11 was only increased in CSF of patients with VZV meningitis. MMP-2-levels were highly elevated in CSF of all 66 VZV patients. The patients with encephalitis had the most significantly increased levels of MMPs in CSF, and MMP-3, MMP-8, and MMP-12 were exclusively increased in this group, whereas MMP-9 in CSF was increased in the patients with VZV meningitis. CONCLUSIONS: We show that both chemokines and MMPs are elevated in the CSF of patients with VZV CNS infections. Encephalitis and meningitis patients differed with respect to other chemokines (CXCL11) and MMPs (MMP-3, MMP-8, MMP-9, and MMP-12), indicating that different location of the virus gives rise to qualitative differences in the ensuing inflammatory response. In addition, the pronounced increase of MMPs in CSF of the patients with encephalitis suggests an association to the severity of this manifestation, compared to VZV meningitis and Ramsay Hunt syndrome. The role of MMPs in association to chemokines should be further investigated to evaluate their significance in the neuropathogenesis of VZV CNS infections and as a potential target for new treatment alternatives.

The Noncoding RNA nc886 Regulates PKR Signaling and Cytokine Production in Human Cells.

Protein kinase RNA-activated (PKR) is a cytoplasmic receptor for dsRNA, and as such is involved in detection of viral infection. On binding dsRNA, PKR dimerizes, autophosphorylates, and then phosphorylates its substrate, eukaryotic translation initiation factor 2 subunit α (eIF2α), causing inhibition of mRNA translation and shutdown of viral protein production. However, active PKR has also been found to be involved in the NF-κB signaling pathway by inducing phosphorylation of IκBα. PKR is regulated by the noncoding RNA nc886, which has altered expression in cancer. We have found that expression of nc886 is highly upregulated during activation of human CD4+ T cells. As has been described in other cell types, nc886 bound to PKR in human T cell lysates, preventing PKR phosphorylation by polyinosinic:polycytidylic acid or HIV trans-activation response element RNA in lysates of T cell lines or primary human CD4+ T cells. Using clonal human T cell lines, we found that nc886 expression was strictly required for IFN-γ and IL-2 expression and secretion after T cell activation but did not affect proliferation or activation-induced cell death. In stimulated human PBMCs, nc886 expression strongly correlated with IFN-γ expression. Although nc886 inhibited PKR activation by dsRNA, it was required for PKR phosphorylation during T cell stimulation, with subsequent NF-κB signaling and CREB phosphorylation. nc886 also regulated PKR phosphorylation during human monocyte-derived macrophage activation. We have therefore identified nc886 as a noncoding RNA marker of T cell activation and regulator of PKR-dependent signaling.

Extracts of Equisetum giganteum L and Copaifera reticulate Ducke show strong antiviral activity against the sexually transmitted pathogen herpes simplex virus type 2.

ETHNOPHARMACOLOGICAL RELEVANCE: Equisetum giganteum L and Copaifera reticulate Ducke have been traditionally used by women of the Tacana tribe in the Bolivian Amazonas for genital hygiene and for treatment of genital infection/inflammation. AIM OF THE STUDY: To assess the ability of extracts from Equisetum giganteum L and Copaifera reticulate Ducke to block genital viral infection by herpes simplex virus type 2. MATERIALS AND METHODS: Equisetum giganteum L and Copaifera reticulate Ducke were collected from the Amazon region of La Paz, Bolivia. Extracts were prepared and screened for anti-viral activity against herpes simplex virus type 2 (HSV-2) using both in vitro and in in vivo models of infection. RESULTS: Equisetum giganteum L and Copaifera reticulate Ducke efficiently blocked HSV-2 infection of cell cultures without major cell cytotoxic effects. Extracts of Equisetum giganteum L and Copaifera reticulate Ducke could prevent HSV-2 disease development when administered together with virus in a mouse model of genital HSV-2 infection. In vitro analyses revealed that both plant extracts exerted their anti-HSV-2 effects by interfering with viral cell attachment and entry, but could not block viral replication post entry. CONCLUSIONS: These studies show that extracts of Equisetum giganteum L and Copaifera reticulate Ducke have potent antiviral activities against HSV-2 comparable to those two previously identified plants, Croton lechleri Müll. Arg. and Uncaria tomentosa (Willd. ex Schult.) DC. These studies confirm that plants used by the Tacana tribe could be explored further for the development of novel topical antiviral microbicides.

Maturation-dependent expression of AIM2 in human B-cells.

Intracellular DNA- and RNA-sensing receptors, such as the IFN-inducible protein Absent in Melanoma 2 (AIM2), serve as host sensors against a wide range of infections. Immune sensing and inflammasome activation by AIM2 has been implicated in innate antiviral recognition in many experimental systems using cell-lines and animal models. However, little is known about the expression and function of AIM2 in freshly isolated human cells. In this study we investigated the expression of AIM2 in different cell types derived from human cord and adult peripheral blood, in steady state and following in vitro-activation. Adult but not cord blood B-cells expressed high levels of AIM2 mRNA at steady state. In adults, AIM2 was primarily expressed in mature memory CD27+ B-cells. Both adult and cord blood derived B-cells could induce their transcription of AIM2 mRNA in response to type II IFN but not type I IFN or the AIM2 ligand poly dA:dT. Upon B-cell receptor stimulation, B-cells from adult blood expressed reduced levels of AIM2 mRNA. In addition, we show that adult B-cells were able to release IL-1ß upon stimulation with synthetic DNA. We conclude that functional AIM2 is preferentially expressed in adult human CD27+ B-cells, but is absent in cord blood mononuclear cells.

CXCL11 production in cerebrospinal fluid distinguishes herpes simplex meningitis from herpes simplex encephalitis.

BACKGROUND: The closely related herpes simplex viruses 1 and 2 can cause inflammations of the central nervous system (CNS), where type 1 most often manifest as encephalitis (HSE), and type 2 as meningitis (HSM). HSE is associated with severe neurological complications, while HSM is benign in adults. We proposed that studying the chemokine and cytokine production in cerebrospinal fluid (CSF) and serum could indicate why two closely related viruses exhibit different severity of their accompanied CNS inflammation. METHODS: Secretion patterns of 30 chemokines and 10 cytokines in CSF of adult patients with acute HSE (n = 14) and HSM (n = 20) in the initial stage of disease were analyzed and compared to control subjects without viral central nervous system infections and to levels in serum. RESULTS: Most measured chemokines and cytokines increased in CSF of HSE and HSM patients. Overall, the CSF chemokine levels were higher in CSF of HSM patients compared to HSE patients. However, only five chemokines reached levels in the CSF that exceeded those in serum facilitating a positive CSF-serum chemokine gradient. Of these, CXCL8, CXCL9, and CXCL10 were present at high levels both in HSE and HSM whereas CXCL11 and CCL8 were present in HSM alone. Several chemokines were also elevated in serum of HSE patients but only one in HSM patients. No chemokine in- or efflux between CSF and serum was indicated as the levels of chemokines in CSF and serum did not correlate. CONCLUSIONS: We show that HSM is associated with a stronger and more diverse inflammatory response in the CNS compared to HSE in the initial stage of disease. The chemokine patterns were distinguished by the exclusive local CNS production of CXCL11 and CCL8 in HSM. Inflammation in HSM appears to be restricted to the CNS whereas HSE also was associated with systemic inflammation.