Suppression of proinflammatory cytokine expression by herpes simplex virus type 1

Herpes Simplex Virus ICP27 Protein Inhibits AIM 2-Dependent Inflammasome Influencing Pro-Inflammatory Cytokines Release in Human Pigment Epithelial Cells (hTert-RPE 1)

Although Herpes simplex virus type 1 (HSV-1) has been deeply studied, significant gaps remain in the fundamental understanding of HSV-host interactions: our work focused on studying the Infected Cell Protein 27 (ICP27) as an inhibitor of the Absent-in-melanoma-2 (AIM 2) inflammasome pathway, leading to reduced pro-inflammatory cytokines that influence the activation of a protective innate immune response to infection. To assess the inhibition of the inflammasome by the ICP27, hTert-immortalized Retinal Pigment Epithelial cells (hTert-RPE 1) infected with HSV-1 wild type were compared to HSV-1 lacking functional ICP27 (HSV-1∆ICP27) infected cells. The activation of the inflammasome by HSV-1∆ICP27 was demonstrated by quantifying the gene and protein expression of the inflammasome constituents using real-time PCR and Western blot. The detection of the cleavage of the pro-caspase-1 into the active form was performed by using a bioluminescent assay, while the quantification of interleukins 1β (IL-1β) and 18 (IL-18)released in the supernatant was quantified using an ELISA assay. The data showed that the presence of the ICP27 expressed by HSV-1 induces, in contrast to HSV-1∆ICP27 vector, a significant downregulation of AIM 2 inflammasome constituent proteins and, consequently, the release of pro-inflammatory interleukins into the extracellular environment reducing an effective response in counteracting infection.

Viral MicroRNAs in Herpes Simplex Virus 1 Pathobiology

Simplexvirus humanalpha1 (Herpes simplex virus type 1 [HSV-1]) infects millions of people globally, manifesting as vesiculo-ulcerative lesions of the oral or genital mucosa. After primary infection, the virus establishes latency in the peripheral neurons and reactivates sporadically in response to various environmental and genetic factors. A unique feature of herpesviruses is their ability to encode tiny noncoding RNAs called microRNA (miRNAs). Simplexvirus humanalpha1 encodes eighteen miRNA precursors that generate twentyseven different mature miRNA sequences. Unique Simplexvirus humanalpha1 miRNAs repertoire is expressed in lytic and latent stages and exhibits expressional disparity in various cell types and model systems, suggesting their key pathological functions. This review will focus on elucidating the mechanisms underlying the regulation of host-virus interaction by HSV-1 encoded viral miRNAs. Numerous studies have demonstrated sequence- specific targeting of both viral and host transcripts by Simplexvirus humanalpha1 miRNAs. While these noncoding RNAs predominantly target viral genes involved in viral life cycle switch, they regulate host genes involved in antiviral immunity, thereby facilitating viral evasion and lifelong viral persistence inside the host. Expression of Simplexvirus humanalpha1 miRNAs has been associated with disease progression and resolution. Systemic circulation and stability of viral miRNAs compared to viral mRNAs can be harnessed to utilize their potential as diagnostic and prognostic markers. Moreover, functional inhibition of these enigmatic molecules may allow us to devise strategies that have therapeutic significance to contain Simplexvirus humanalpha1 infection.

Peste des petits ruminants virus non-structural V and C proteins interact with the NF-κB p65 subunit and modulate pro-inflammatory cytokine gene induction

Peste des petits ruminants virus (PPRV) is known to induce transient immunosuppression in infected small ruminants by modulating several cellular pathways involved in the antiviral immune response. Our study shows that the PPRV-coded non-structural proteins C and V can interact with the cellular NF-κB p65 subunit. The PPRV-C protein interacts with the transactivation domain (TAD) while PPRV-V interacts with the Rel homology domain (RHD) of the NF-κB p65 subunit. Both viral proteins can suppress the NF-κB transcriptional activity and NF-κB-mediated transcription of cellular genes. PPRV-V protein expression can significantly inhibit the nuclear translocation of NF-κB p65 upon TNF-α stimulation, whereas PPRV-C does not affect it. The NF-κB-mediated pro-inflammatory cytokine gene expression is significantly downregulated in cells expressing PPRV-C or PPRV-V protein. Our study provides evidence suggesting a role of PPRV non-structural proteins V and C in the modulation of NF-κB signalling through interaction with the NF-κB p65 subunit.

Host immunological responses facilitate development of SARS-CoV-2 mutations in patients receiving monoclonal antibody treatments

BackgroundThe role of host immunity in emergence of evasive SARS-CoV-2 Spike mutations under therapeutic monoclonal antibody (mAb) pressure remains to be explored.MethodsIn a prospective, observational, monocentric ORCHESTRA cohort study, conducted between March 2021 and November 2022, mild-to-moderately ill COVID-19 patients (n = 204) receiving bamlanivimab, bamlanivimab/etesevimab, casirivimab/imdevimab, or sotrovimab were longitudinally studied over 28 days for viral loads, de novo Spike mutations, mAb kinetics, seroneutralization against infecting variants of concern, and T cell immunity. Additionally, a machine learning-based circulating immune-related biomarker (CIB) profile predictive of evasive Spike mutations was constructed and confirmed in an independent data set (n = 19) that included patients receiving sotrovimab or tixagevimab/cilgavimab.ResultsPatients treated with various mAbs developed evasive Spike mutations with remarkable speed and high specificity to the targeted mAb-binding sites. Immunocompromised patients receiving mAb therapy not only continued to display significantly higher viral loads, but also showed higher likelihood of developing de novo Spike mutations. Development of escape mutants also strongly correlated with neutralizing capacity of the therapeutic mAbs and T cell immunity, suggesting immune pressure as an important driver of escape mutations. Lastly, we showed that an antiinflammatory and healing-promoting host milieu facilitates Spike mutations, where 4 CIBs identified patients at high risk of developing escape mutations against therapeutic mAbs with high accuracy.ConclusionsOur data demonstrate that host-driven immune and nonimmune responses are essential for development of mutant SARS-CoV-2. These data also support point-of-care decision making in reducing the risk of mAb treatment failure and improving mitigation strategies for possible dissemination of escape SARS-CoV-2 mutants.FundingThe ORCHESTRA project/European Union's Horizon 2020 research and innovation program.

Vaccinium bracteatum Thunb Extract Inhibits HSV-1 Infection by Regulating ER Stress and Apoptosis

Herpes simplex Type 1 (HSV-1) is a neurotropic virus that infects the peripheral and central nervous system. Usually, after primary infection in epithelial cells, HSV-1 migrates retrograde to the peripheral nervous system (PNS), where it establishes a latent infection. HSV-1 can remain latent in the nervous system, and its reactivation in the brain can rarely cause acute HSV-1 encephalitis, often a life-threatening condition, or asymptomatic reactivations that could lead to neuronal damage and ultimately neurodegenerative disorders. Acyclovir and related nucleoside analogs have been used as therapeutic agents for HSV-1 infection, but resistance to the drug can arise, and the protective effect of HSV-1 on brain cells is limited. Therefore, there is an urgent need for research into safe and effective new antiviral agents that can protect brain cells from the damage that is caused by HSV-1 infection. Vaccinium bracteatum Thunb. (VBT) is widely distributed in Korea and China, and has pharmacological actions such as anti-inflammatory, antioxidant, and antidiabetic activity. Studies on the antiviral effect of VBT on HSV-1 infection have not been reported so far. Therefore, we sought to determine the HSV-1 antiviral effect and molecular mechanism of VBT at the cellular level. We confirmed that VBT repressed the VP16 and IE genes in both Vero and SK-N-SH cells. We also found that the generation of HSV-1 virions was inhibited by VBT treatment. VBT inhibited the activities of the HSV-1-induced endoplasmic reticulum (ER) stressors PERK, ATF4, and CHOP. We confirmed that VBT inhibited the activity of apoptosis factors by regulating the expression of death receptor (DR) after HSV-1 infection. As HSV-1 is closely associated with brain diseases, the study of the antiviral drug effects and mechanism of VBT is meaningful. Further studies using animal models of infection will also be performed to determine the potential of VBT as an antiviral agent.

Patterns of serum immune biomarkers during elephant endotheliotropic herpesvirus viremia in Asian and African elephants

Hemorrhagic disease (HD) caused by a group of elephant endotheliotropic herpesviruses (EEHV) is one of the leading causes of death for young elephants in human care. These viruses are widespread and typically persist latently in adult elephants with no negative effects; however, in juvenile Asian and more recently young African elephants, the onset of disease can be rapid and the mortality rate high. Measuring biomarkers associated with the immune response could be beneficial to understanding underlying disease processes, as well as the management of infection and HD. The goal of this study was to measure acute phase proteins and cytokines in serum collected from elephants infected with EEHV (13 Asian and 1 African) and compare concentrations according to presence, severity and outcome of disease. Serum amyloid A (SAA) and haptoglobin (HP) were higher in elephants with EEHV viremia than those without; concentrations increased with increasing viral load, and were higher in fatal cases compared to those that survived. In Asian elephants, SAA was also higher during EEHV1 viremia compared to EEHV5. Cytokine concentrations were typically low, and no statistical differences existed between groups. However, in individuals with detectable levels, longitudinal profiles indicated changes in tumor necrosis factor alpha (TNF-α) and interleukin-2 (IL-2) that may reflect an immune response to EEHV infection. However, the overall low concentrations detected using previously validated assays do not support the presence of a 'cytokine storm' and suggest more work is needed to understand if sub-optimal immune responses could be involved in disease progression. These results highlight the potential benefit of measuring circulating biomarker concentrations, such as APPs and cytokines, to improve our understanding of EEHV viremia and HD, assist with monitoring the progression of disease and determining the impact of interventions.

Molecular mechanisms of human herpes viruses inferring with host immune surveillance

Several human herpes viruses (HHVs) exert oncogenic potential leading to malignant transformation of infected cells and/or tissues. The molecular processes induced by viral-encoded molecules including microRNAs, peptides, and proteins contributing to immune evasion of the infected host cells are equal to the molecular processes of immune evasion mediated by tumor cells independently of viral infections. Such major immune evasion strategies include (1) the downregulation of proinflammatory cytokines/chemokines as well as the induction of anti-inflammatory cytokines/chemokines, (2) the downregulation of major histocompatibility complex (MHC) class Ia directly as well as indirectly by downregulation of the components involved in the antigen processing, and (3) the downregulation of stress-induced ligands for activating receptors on immune effector cells with NKG2D leading the way. Furthermore, (4) immune modulatory molecules like MHC class Ib molecules and programmed cell death1 ligand 1 can be upregulated on infections with certain herpes viruses. This review article focuses on the known molecular mechanisms of HHVs modulating the above-mentioned possibilities for immune surveillance and even postulates a temporal order linking regular tumor immunology with basic virology and offering putatively novel insights for targeting HHVs.

Pathobiology and treatment of viral keratitis

Keratitis is one of the most prevalent ocular diseases manifested by partial or total loss of vision. Amongst infectious (viz., microbes including bacteria, fungi, amebae, and viruses) and non-infectious (viz., eye trauma, chemical exposure, and ultraviolet exposure, contact lens) risk factors, viral keratitis has been demonstrated as one of the leading causes of corneal opacity. While many viruses have been shown to cause keratitis (such as rhabdoviruses, coxsackieviruses, etc.), herpesviruses are the predominant etiologic agent of viral keratitis. This chapter will summarize current knowledge on the prevalence, diagnosis, and pathobiology of viral keratitis. Virus-mediated immunomodulation of host innate and adaptive immune components is critical for viral persistence, and dysfunctional immune responses may cause destruction of ocular tissues leading to keratitis. Immunosuppressed or immunocompromised individuals may display recurring disease with pronounced severity. Early diagnosis of viral keratitis is beneficial for disease management and response to treatment. Finally, we have discussed current and emerging therapies to treat viral keratitis.

Role of Inflammation in Virus Pathogenesis during Pregnancy

Viral infections during pregnancy lead to a spectrum of maternal and fetal outcomes, ranging from asymptomatic disease to more critical conditions presenting with severe maternal morbidity, stillbirth, preterm birth, intrauterine growth restriction, and fetal congenital anomalies, either apparent at birth or later in life. In this article, we review the pathogenesis of several viral infections that are particularly relevant in the context of pregnancy and intrauterine inflammation. Understanding the diverse mechanisms employed by viral pathogens as well as the repertoire of immune responses induced in the mother may help to establish novel therapeutic options to attenuate changes in the maternal-fetal interface and prevent adverse pregnancy outcomes.

Modulation of cell proteome by 25-hydroxycholesterol and 27-hydroxycholesterol: A link between cholesterol metabolism and antiviral defense

Physiological cholesterol metabolism implies the generation of a series of oxidized derivatives, whose oxysterols are by far the most investigated ones for their potential multifaceted involvement in human pathophysiology. In this regard, noteworthy is the broad antiviral activity displayed by defined side chain oxysterols, in particular 25-hydroxycholesterol (25HC) and 27-hydroxycholesterol (27HC). Although their antiviral mechanism(s) may vary depending on virus/host interaction, these oxysterols share the common feature to hamper viral replication by interacting with cellular proteins. Here reported is the first analysis of the modulation of a cell proteome by these two oxysterols, that, besides yielding additional clues about their potential involvement in the regulation of sterol metabolism, provides novelinsights about the mechanism underlying the inhibition of virus entry and trafficking within infected cells. We show here that both 25HC and 27HC can down-regulate the junction adhesion molecule-A (JAM-A) and the cation independent isoform of mannose-6-phosphate receptor (MPRci), two crucial molecules for the replication of all those viruses that exploit adhesion molecules and the endosomal pathway to enter and diffuse within target cells.

A pro-inflammatory CD8+ T-cell subset patrols the cervicovaginal tract

The immune system of the cervicovaginal tract (CVT) must balance immunosurveillance and active immunity against pathogens with maintenance of tolerance to resident microbiota and to fetal and partner antigens for reproductive purposes. Thus, we predicted that CVT immunity is characterized by distinctive features compared to blood and other tissue compartments. Indeed, we found that CVT CD8+ T-cells had unique transcriptional profiles, particularly in their cytokine signature, compared to that reported for CD8+ T-cells in other tissue sites. Among these CVT CD8+ T-cells, we identified a CD69- CD103- subset that was characterized by reduced migration in response to tissue-exit signals and higher pro-inflammatory potential as compared to their blood counterpart. These inflammatory mucosal CD8+ T-cells (Tim) were increased in frequency in the CVT of individuals with chronic infection, pointing to a potential role in perpetuating inflammation. Our findings highlight the specialized nature of immunity within the CVT and identify Tim cells as potential therapeutic targets to tame tissue inflammation upon chronic infection.

Blockade of PD-1 and LAG-3 Immune Checkpoints Combined with Vaccination Restores the Function of Antiviral Tissue-Resident CD8+ TRM Cells and Reduces Ocular Herpes Simplex Infection and Disease in HLA Transgenic Rabbits

Chronic viruses such as herpes simplex virus 1 (HSV-1) evade the hosts' immune system by inducing the exhaustion of antiviral T cells. In the present study, we found that exhausted HSV-specific CD8⁺ T cells, with elevated expression of programmed death ligand-1 (PD-1) and lymphocyte activation gene-3 (LAG-3) receptors were frequent in symptomatic patients, with a history of numerous episodes of recurrent corneal herpetic disease, compared to asymptomatic patients who never had corneal herpetic disease. Subsequently, using a rabbit model of recurrent ocular herpes, we found that the combined blockade of PD-1 and LAG-3 pathways with antagonist antibodies significantly restored the function of tissue-resident antiviral CD8⁺ T_RM cells in both the cornea and the trigeminal ganglia (TG). An increased number of functional tissue-resident HSV-specific CD8⁺ T_RM cells in latently infected rabbits was associated with protection against recurrent herpes infection and disease. Compared to the PD-1 or LAG-3 blockade alone, the combined blockade of PD-1 and LAG-3 appeared to have a synergistic effect in generating frequent polyfunctional Ki-67⁺, IFN-γ⁺, CD107⁺, and CD8⁺ T cells. Moreover, using the human leukocyte antigen (HLA) transgenic rabbit model, we found that dual blockade of PD-1 and LAG-3 reinforced the effect of a multiepitope vaccine in boosting the frequency of HSV-1-specific CD8⁺ T_RM cells and reducing disease severity. Thus, both the PD-1 and the LAG-3 exhaustion pathways play a fundamental role in ocular herpes T cell immunopathology and provide important immune checkpoint targets to combat ocular herpes.IMPORTANCE HSV-specific tissue-resident memory CD8⁺ T_RM cells play a critical role in preventing virus reactivation from latently infected TG and subsequent virus shedding in tears that trigger the recurrent corneal herpetic disease. In this report, we determined how the dual blockade of PD-1 and LAG-3 immune checkpoints, combined with vaccination, improved the function of CD8⁺ T_RM cells associated with a significant reduction in recurrent ocular herpes in HLA transgenic (Tg) rabbit model. The combined blockade of PD-1 and LAG-3 appeared to have a synergistic effect in generating frequent polyfunctional CD8⁺ T_RM cells that infiltrated both the cornea and the TG. The preclinical findings using the established HLA Tg rabbit model of recurrent herpes highlight that blocking immune checkpoints combined with a T cell-based vaccine would provide an important strategy to combat recurrent ocular herpes in the clinic.

Interactome and Proteome Dynamics Uncover Immune Modulatory Associations of the Pathogen Sensing Factor cGAS

Viral DNA sensing is an essential component of the mammalian innate immune response. Upon binding viral DNA, the cyclic-GMP-AMP synthase (cGAS) catalyzes the production of cyclic dinucleotides to induce type I interferons. However, little is known about how cGAS is homeostatically maintained or regulated upon infection. Here, we define cytoplasmic cGAS interactions with cellular and viral proteins upon herpes simplex virus type 1 (HSV-1) infection in primary human fibroblasts. We compare several HSV-1 strains (wild-type, d109, d106) that induce cytokine responses and apoptosis and place cGAS interactions in the context of temporal proteome alterations using isobaric-labeling mass spectrometry. Follow-up analyses establish a functional interaction between cGAS and 2'-5'-oligoadenylate synthase-like protein OASL. The OAS-like domain interacts with the cGAS Mab21 domain, while the OASL ubiquitin-like domain further inhibits cGAS-mediated interferon response. Our findings explain how cGAS may be inactively maintained in cellular homeostasis, with OASL functioning as a negative feedback loop for cytokine induction.

Enhanced expression of IFI16 and RIG-I in human third-trimester placentas following HSV-1 infection

The innate immune response in the placenta depends on the ability of maternal immune cells and fetal trophoblast cells to detect and eliminate invading pathogens through germline-encoded pattern recognition receptors (PRRs). In the present study, we analysed the transcripts and protein expression of interferon (IFN)-inducible protein (IFI)16, melanoma differentiation-associated protein 5 (MDA5), RIG-I-like receptor (RIG-I) and Toll-like receptor (TLR)-3 in third-trimester human placentas and investigated cytokine profiles generated during herpes simplex type 1 (HSV-1) infection. Decidual and chorionic villous biopsies (38-42 weeks of gestation) were obtained from healthy women immediately after a caesarean section. The expression of the DDX58 (RIG-I), IFIH1 (MDA5), IFI16 and TLR3 transcripts was measured using quantitative real-time polymerase chain reaction (qRT-PCR). Extracellular cytokine and PRRs levels were then quantified by enzyme-linked immunosorbent assays (ELISAs). All examined PRRs genes, including DDX58, IFIH1, IFI16 and TLR3, were expressed constitutively at the mRNA and protein levels in the placental biopsies. The concentration of the IFI16 protein was increased in HSV-1-infected decidual and chorionic villous explants compared to those of mock-infected tissues (P = 0·029). Higher protein expression levels of RIG-I in both the maternal and fetal parts of the placenta were found (P = 0·009 and P = 0·004, respectively). In addition, increased production of IFN-β by HSV-1-infected tissues was noticed (P = 0·004 for decidua, P = 0·032 for chorionic villi). No significant differences in the IFN-α, interleukin (IL)-6 and IL-8 levels were found. These results showed that HSV-1 infection can enhance the expression of IFI16 and RIG-I proteins in the human term placenta.

Cytokines Produced in Response to Varicella-Zoster Virus Infection of ARPE-19 Cells Stimulate Lymphocyte Chemotaxis

Posterior uveitis is an ocular complication that can occur with reactivation of varicella-zoster virus (VZV). It may lead to loss of vision due to retinal detachment and chronic inflammation, which often causes more severe disease than the virus infection itself. To increase our understanding of the immune response, we infected the retinal pigment epithelial (RPE) cell line, ARPE-19, with cell-associated VZV and compared its response to that of the MeWo cell line using multiplex assays. We observed (1) a difference in the magnitude and kinetics of cytokine responses between the 2 cell types and (2) differential migration of CD4+ and CD8+ T cells towards these cytokines. Thus, our data provide information about the cytokine and lymphocytic responses to VZV infection of RPE cells, thereby providing a useful platform for future studies to address mechanisms underlying the immunopathology of VZV-associated posterior uveitis.

Different inflammatory responses of bovine oviductal epithelial cells in vitro to bacterial species with distinct pathogenicity characteristics and passage number

The bovine oviduct provides the site for fertilization and early embryonic development. Modifications to this physiological environment, for instance the presence of pathogenic bacterial species, could diminish reproductive success at early stages of pregnancy. The aim of this study was to elucidate the inflammatory responses of bovine oviductal epithelial cells (BOEC) to a pathogenic bacterial species (Trueperella pyogenes) and a potentially pathogenic bacterium (Bacillus pumilus). BOEC from four healthy animals were isolated, cultured in passage 0 (P0) and passaged until P3. Trypan blue staining determined BOEC viability during 24 h co-culture with different multiplicities of infection (MOI) of T. pyogenes (MOI 0.01, 0.05, 0.1 and 1) or B. pumilus (MOI 1 and 10). BOEC remained viable when co-cultured with T. pyogenes at MOI 0.01 and with B. pumilus at MOI 1 and 10. Extracted total RNA from control and bacteria co-cultured samples was subjected to reverse transcription-quantitative polymerase chain reaction (RTq-PCR) to determine mRNA expression of various studied genes. The rate of release of interleukin 8 (IL8) and prostaglandin E₂ (PGE₂) from BOEC was measured by ELISA after 24 h co-culture with bacteria. RT-qPCR of various selected pro-inflammatory factors revealed similar mRNA expression of pro-inflammatory factors in BOEC co-cultured with T. pyogenes and in the controls. Higher mRNA expression of IL 1A, -1B, tumor necrosis factor alpha and CXC ligand (CXCL) 1/2, -3, -5 and IL8 and PG synthesis enzymes in BOEC co-cultured with B. pumilus was observed. In the presence of B. pumilus a higher amount of IL8 and PGE₂ was released from BOEC than from controls. The viability and pro-inflammatory response of P3 BOEC incubated with bacteria was lower than in P0 BOEC. These findings illustrate the pathogenicity of T. pyogenes towards BOEC in detail and the potential role of B. pumilus in generating inflammation in oviductal cells. Culturing conditions influenced the pro-inflammatory responses of BOEC towards bacteria. Therefore, researchers conducting epithelial-bacterial in vitro co-culture should not underestimate the effects of these parameters.

Inhibition of herpes simplex-1 virus replication by 25-hydroxycholesterol and 27-hydroxycholesterol

Oxysterols are known pleiotropic molecules whose antiviral action has been recently discovered. Here reported is the activity of a panel of oxysterols against HSV-1 with the identification of a new mechanism of action. A marked antiviral activity not only of 25HC but also of 27HC against HSV-1 was observed either if the oxysterols were added before or after infection, suggesting an activity unrelated to the viral entry inhibition as proposed by previous literature. Therefore, the relation between the pro-inflammatory activity of oxysterols and the activation of NF-kB and IL-6 induced by HSV-1 in the host cell was investigated. Indeed, cell pre-incubation with oxysterols further potentiated IL-6 production as induced by HSV-1 infection with a consequent boost of the interleukin's total cell secretion. Further, a direct antiviral effect of IL-6 administration to HSV-1 infected cells was demonstrated, disclosing an additional mechanism of antiviral action by both 25HC and 27HC.

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25HC and 27HC markedly inhibit HSV-1 replication in a standard cell culture system.

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Cell pre-incubation with oxysterols potentiates IL-6 production as induced by HSV-1.

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The concentration of IL-6 induced by oxysterols actually inhibits HSV-1 replication.

Role of Bacterial Exopolysaccharides as Agents in Counteracting Immune Disorders Induced by Herpes Virus

Extreme marine environments, such as the submarine shallow vents of the Eolian Islands (Italy), offer an almost unexplored source of microorganisms producing unexploited and promising biomolecules for pharmaceutical applications. Thermophilic and thermotolerant bacilli isolated from Eolian vents are able to produce exopolysaccharides (EPSs) with antiviral and immunomodulatory effects against Herpes simplex virus type 2 (HSV-2). HSV-2 is responsible for the most common and continuously increasing viral infections in humans. Due to the appearance of resistance to the available treatments, new biomolecules exhibiting different mechanisms of action could provide novel agents for treating viral infections. The EPSs hinder the HSV-2 replication in human peripheral blood mononuclear cells (PBMC) but not in WISH (Wistar Institute Susan Hayflic) cells line, indicating that cell-mediated immunity was involved in the antiviral activity. High levels of Th1-type cytokines were detected in PBMC treated with all EPSs, while Th2-type cytokines were not induced. These EPSs are water soluble exopolymers able to stimulate the immune response and thus contribute to the antiviral immune defense, acting as immunomodulators. As stimulants of Th1 cell-mediated immunity, they could lead to the development of novel drugs as alternative in the treatment of herpes virus infections, as well as in immunocompromised host.

Persistent Foot-and-Mouth Disease Virus Infection in the Nasopharynx of Cattle; Tissue-Specific Distribution and Local Cytokine Expression

Tissues obtained post-mortem from cattle persistently infected with foot-and-mouth disease virus (FMDV) were analyzed to characterize the tissue-specific localization of FMDV and partial transcriptome profiles for selected immunoregulatory cytokines. Analysis of 28 distinct anatomic sites from 21 steers infected with FMDV serotype A, O or SAT2, had the highest prevalence of overall viral detection in the dorsal nasopharynx (80.95%) and dorsal soft palate (71.43%). FMDV was less frequently detected in laryngeal mucosal tissues, oropharyngeal mucosal sites, and lymph nodes draining the pharynx. Immunomicroscopy indicated that within persistently infected mucosal tissues, FMDV antigens were rarely detectable within few epithelial cells in regions of mucosa-associated lymphoid tissue (MALT). Transcriptome analysis of persistently infected pharyngeal tissues by qRT-PCR for 14 cytokine genes indicated a general trend of decreased mRNA levels compared to uninfected control animals. Although, statistically significant differences were not observed, greatest suppression of relative expression (RE) was identified for IP-10 (RE = 0.198), IFN-β (RE = 0.269), IL-12 (RE = 0.275), and IL-2 (RE = 0.312). Increased relative expression was detected for IL-6 (RE = 2.065). Overall, this data demonstrates that during the FMDV carrier state in cattle, viral persistence is associated with epithelial cells of the nasopharynx in the upper respiratory tract and decreased levels of mRNA for several immunoregulatory cytokines in the infected tissues.

Almond Skin Inhibits HSV-2 Replication in Peripheral Blood Mononuclear Cells by Modulating the Cytokine Network

We have investigated the effect of almond skin extracts on the production of pro-inflammatory and anti-inflammatory cytokines in human peripheral blood mononuclear cells (PBMCs). PBMCs were either infected or not by herpes simplex virus type 2 (HSV-2), with and without prior treatment with almond skin extracts. Production of IL-17 induced by HSV-2 was inhibited by natural skins (NS) treatment. NS triggered PBMC in releasing IFN-α, IFN-γ and IL-4 in cellular supernatants. These results may explain the antiviral potential of almond skins.

Genomic analysis of host - Peste des petits ruminants vaccine viral transcriptome uncovers transcription factors modulating immune regulatory pathways

Peste des petits ruminants (PPR), is an acute transboundary viral disease of economic importance, affecting goats and sheep. Mass vaccination programs around the world resulted in the decline of PPR outbreaks. Sungri 96 is a live attenuated vaccine, widely used in Northern India against PPR. This vaccine virus, isolated from goat works efficiently both in sheep and goat. Global gene expression changes under PPR vaccine virus infection are not yet well defined. Therefore, in this study we investigated the host-vaccine virus interactions by infecting the peripheral blood mononuclear cells isolated from goat with PPRV (Sungri 96 vaccine virus), to quantify the global changes in the transcriptomic signature by RNA-sequencing. Viral genome of Sungri 96 vaccine virus was assembled from the PPRV infected transcriptome confirming the infection and demonstrating the feasibility of building a complete non-host genome from the blood transcriptome. Comparison of infected transcriptome with control transcriptome revealed 985 differentially expressed genes. Functional analysis showed enrichment of immune regulatory pathways under PPRV infection. Key genes involved in immune system regulation, spliceosomal and apoptotic pathways were identified to be dysregulated. Network analysis revealed that the protein - protein interaction network among differentially expressed genes is significantly disrupted in infected state. Several genes encoding TFs that govern immune regulatory pathways were identified to co-regulate the differentially expressed genes. These data provide insights into the host - PPRV vaccine virus interactome for the first time. Our findings suggested dysregulation of immune regulatory pathways and genes encoding Transcription Factors (TFs) that govern these pathways in response to viral infection.

Innate recognition of alphaherpesvirus DNA

Alphaherpesviruses include human and animal pathogens, such as herpes simplex virus type 1, which establish life-long latent infections with episodes of recurrence. The immunocompetence of the infected host is an important determinant for the outcome of infections with alphaherpesviruses. Recognition of pathogen-associated molecular patterns by pattern recognition receptors is an essential, early step in the innate immune response to pathogens. In recent years, it has been discovered that herpesvirus DNA is a strong inducer of the innate immune system. The viral genome can be recognized in endosomes by TLR9, as well as intracellularly by a variety of DNA sensors, the best documented being cGAS, RNA Pol III, IFI16, and AIM2. These DNA sensors use converging signaling pathways to activate transcription factors, such as IRF3 and NF-κB, which induce the expression of type I interferons and other inflammatory cytokines and activate the inflammasome. This review summarizes the recent literature on the innate sensing of alphaherpesvirus DNA, the mechanisms of activation of the different sensors, their mechanisms of signal transduction, their physiological role in defense against herpesvirus infection, and how alphaherpesviruses seek to evade these responses to allow establishment and maintenance of infection.

In vitro antiviral and immunomodulatory activity of arbidol and structurally related derivatives in herpes simplex virus type 1-infected human keratinocytes (HaCat)

Arbidol (ARB) is an antiviral drug that has broad-spectrum activity against a number of viral infections. To date, there are no specific data regarding its effects against a herpesvirus. Here, the in vitro antiviral effect of ARB and structurally related derivatives were evaluated in HaCat cells on different steps of herpes simplex virus type 1 replication: adsorption, entry and post-entry. The simplified pyrrolidine analogue, 9a2, showed the best antiviral activity in vitro by reducing the plaque numbers by about 50% instead of 42% obtained with ARB at the same concentration. Furthermore, we have reported that all tested compounds evaluated for their immunomodulatory activity showed the ability to reduce the viral proteins VP16 and ICP27 and to modify the virus-induced cytokine expression, allowing the host cell a more efficient antiviral response.

Altered expression of cytokines in mice infected intranasally with two syncytial variants of Herpes simplex virus type 1

Immune evasion strategies are important for the onset and the maintenance of viral infections. Many viruses have evolved mechanisms to counteract or suppress the host immune response. We have previously characterized two syncytial (syn) variants of Herpes simplex 1 (HSV-1) strain F, syn14-1 and syn17-2, obtained by selective pressure with a natural carrageenan. These variants showed a differential pathology in vaginal and respiratory mucosa infection in comparison with parental strain. In this paper, we evaluated the modulation of immune response in respiratory mucosa by these HSV-1 variants. We observed altered levels of Tumor Necrosis Factor-α and Interleukin-6 in lungs of animals infected with the syn14-1 and syn17-2 variants compared with the parental strain. Also, we detected differences in the recruitment of immune cells to the lung in syn variants infected mice. Both variants exhibit one point mutation in the sequence of the gene of glycoprotein D detected in the ectodomain of syn14-1 and the cytoplasmic tail of syn17-2. Results obtained in the present study contribute to the characterization of HSV-1 syn variants and the participation of the cellular inflammatory response in viral pathogenesis.

Recognition of herpes simplex viruses: toll-like receptors and beyond

Herpes simplex viruses (HSVs) are human pathogens that establish lytic and latent infections. Reactivation from latency occurs intermittently, which represents a lifelong source of recurrent infection. In this complex process, HSV triggers and neutralizes innate immunity. Therefore, a dynamic equilibrium between HSV and the innate immune system determines the outcome of viral infection. Detection of HSV involves pathogen recognition receptors that include Toll-like receptors, retinoic acid-inducible gene I-like receptors, and cytosolic DNA sensors. Moreover, innate components or pathways exist to sense membrane fusion upon viral entry into host cells. Consequently, this surveillance network activates downstream transcription factors, leading to the induction of type I interferon and inflammatory cytokines. Not surprisingly, with the capacity to establish chronic infection HSV has evolved strategies that modulate or evade innate immunity. In this review, we describe recent advances pertinent to the interplay of HSV and the induction of innate immunity mediated by pathogen recognition receptors or pathways.

MHC class I cross-presentation by dendritic cells counteracts viral immune evasion

DCs very potently activate CD8(+) T cells specific for viral peptides bound to MHC class I molecules. However, many viruses have evolved immune evasion mechanisms, which inactivate infected DCs and might reduce priming of T cells. Then MHC class I cross-presentation of exogenous viral Ag by non-infected DCs may become crucial to assure CD8(+) T cell responses. Although many vital functions of infected DCs are inhibited in vitro by many different viruses, the contributions of cross-presentation to T cell immunity when confronted with viral immune inactivation in vivo has not been demonstrated up to now, and remains controversial. Here we show that priming of Herpes Simplex Virus (HSV)-, but not murine cytomegalovirus (mCMV)-specific CD8(+) T cells was severely reduced in mice with a DC-specific cross-presentation deficiency. In contrast, while CD8(+) T cell responses to mutant HSV, which lacks crucial inhibitory genes, also depended on CD8α(+) DCs, they were independent of cross-presentation. Therefore HSV-specific CTL-responses entirely depend on the CD8α(+) DC subset, which present via direct or cross-presentation mechanisms depending on the immune evasion equipment of virus. Our data establish the contribution of cross-presentation to counteract viral immune evasion mechanisms in some, but not all viruses.

Effectiveness of HBV vaccination in infants and prediction of HBV prevalence trend under new vaccination plan: findings of a large-scale investigation

BACKGROUND

Hepatitis B virus (HBV) infection remains a severe public health problem. Investigating its prevalence and trends is essential to prevention.

METHODS

To evaluate the effectiveness of HBV vaccination under the 1992 Intervention Program for infants and predicted HBV prevalence trends under the 2011 Program for all ages. We conducted a community-based investigation of 761,544 residents of 12 counties in Zhejiang Province selected according to their location, population density, and economic development. The HBV prevalence trends were predicted by a time-shifting approach. HBV surface antigen (HBsAg) and alanine amino transferase (ALT) were determined.

RESULTS

Of the 761,544 persons screened for HBsAg, 54,132 were positive (adjusted carrier rate 6.13%); 9,455 had both elevated ALT and a positive HBsAg test (standardized rate 1.18%). The standardized HBsAg carrier rate for persons aged ≤20 years was 1.51%. Key factors influencing HBV infection were sex, age, family history, drinking, smoking, employment as a migrant worker, and occupation. With the vaccination program implemented in 2011, we predict that by 2020, the HBsAg carrier rate will be 5.27% and that for individuals aged ≤34 years will reach the 2% upper limit of low prevalence according to the WHO criteria, with a standardized rate of 1.86%.

CONCLUSIONS

The national HBV vaccination program for infants implemented in 1992 has greatly reduced the prevalence of HBV infection. The 2011 program is likely to reduce HBV infection in Zhejiang Province to a low moderate prevalence, and perinatal transmission is expected to be controlled by 2020.

Effects of oat β-glucan on the macrophage cytokine response to herpes simplex virus 1 infection in vitro

Oat β-glucan can counteract the increased risk for Herpes Simplex Virus 1 (HSV-1) infection in mice, the effects of which have, at least in part, been attributed to macrophages. However, the specific responses of macrophages to oat β-glucan treatment in this model have yet to be elucidated. We examined the effects of varying doses of oat β-glucan on the pro-inflammatory cytokine response in both peritoneal and lung macrophages with and without exposure to HSV-1 infection in vitro. Peritoneal and lung macrophages were obtained from mice and cultured with varying concentrations of oat β-glucan (0 (control), 10, 100, and 1,000 μg) for 24 h and supernatants were collected. A standardized dose of HSV-1 was added for a second 24 h incubation period after which supernatants were again collected. Samples were analyzed for interleukin-1β (IL-1β), IL-6, and tumor necrosis factor α (TNF-α) using enzyme linked immunosorbent assay (ELISA). In most cases, oat β-glucan resulted in a dose-dependent increase in pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) in lung and peritoneal macrophages with and without exposure to HSV-1 infection. When comparing across macrophage source, this response was greater for IL-1β and IL-6 in peritoneal macrophages and for TNF-α in lung macrophages. This may be a mechanism for the decreased risk for HSV-1 infection following oat β-glucan feedings in mice.

Differential modulation of cytokine, chemokine and Toll like receptor expression in chickens infected with classical and variant infectious bursal disease virus

Infectious bursal disease (IBD) is an important immunosuppressive disease of chickens. The causative agent, infectious bursal disease virus (IBDV), consists of two serotypes, 1 and 2. Serotype 1 consists of classic IBDV (cIBDV) and variant IBDV (vIBDV). Both of these strains vary in antigenicity and pathogenesis. The goal of this study was to compare the immunopathogenesis of cIBDV and vIBDV. Three-week-old specific pathogen free chickens were inoculated intraocularly with standard challenge strain (STC) (cIBDV) and a variant strain Indiana (IN) (vIBDV). The cIBDV produced more pronounced bursal damage, inflammatory response and infiltration of T cells as compared to vIBDV. There were significant differences in the expression of innate (IFN-α and IFN-β), proinflammatory cytokine and mediator (IL-6 and iNOS) in cIBDV- and vIBDV-infected bursas. The expression of chemokines genes, IL-8 and MIP-α was also higher in cIBDV-infected chickens during the early phase of infection. The expression of Toll like receptor 3 (TLR3) was downregulated at post inoculation days (PIDs) 3, 5, and 7 in the bursas of vIBDV-infected chickens whereas TLR3 was upregulated at PIDs 3 and 5 in cIBDV-infected bursas. In vIBDV-infected bursa, TLR7 expression was downregulated at PIDs 3 and 5 and upregulated at PID 7. However, TLR7 was upregulated at PIDs 3 and 7 in cIBDV-infected bursas. The expression of MyD88 was downregulated whereas TRIF gene expression was upregulated in cIBDV- and vIBDV-infected bursa. These findings demonstrate the critical differences in bursal lesions, infiltration of T cells, expression of cytokines, chemokines and TLRs in the bursa of cIBDV-and vIBDV-infected chickens.

Inhibition of HSV-1 replication by laser diode-irradiation: possible mechanism of action

Herpes labialis are the most frequent clinical manifestations of HSV-1 infection. Epithelial cells are able to respond to HSV-1 presence inducing the expression of IL-6, IL-1, TNF-α and IL-8. These proinflammatory cytokines have a function in the acute-phase response mediation, chemotaxis, inflammatory cell activation and antigen-presenting cells. In the human epithelial cell models, it has been demonstrated that, after an early induction of proinflammatory host response, HSV-1 down-modulates the proinflammatory cytokine production through the accumulation of two viral proteins, ICP4 and ICP27, whose transcription is induced by tegument protein VP16. These viral proteins, through the decreasing of stabilizing the mRNAs of proinflammatory genes, delay cytokine production to an extent that allows the virus to replicate. Moreover, viral transactivating proteins, ICP-0 and VP-16 induce IL-10 expression. The conventional treatment of herpes labialis involves the topical and systemic use of antiviral drugs but it is necessary to find new therapies that can act in a selective and non-cytotoxic manner in viral infection. Laser diode therapy has been considered as a non-invasive alternative treatment to the conventional treatment of herpes labialis in pain therapy, in modulation of inflammation and in wound healing. This study aims to report a possible mechanism of action of laser diode irradiation in prevention and reduction of severity of labial manifestations of herpes labialis virus. We investigated, in an in vitro model of epithelial cells HaCat, the laser-effect on HSV-1 replication and we evaluated the modulation of expression of certain proinflammatory cytokines (TNF-α, IL-1β and IL-6), antimicrobial peptide HBD2, chemokine IL-8 and the immunosuppressive cytokine, IL-10. Our results lead us to hypothesize that LD-irradiation acts in the final stage of HSV-1 replication by limiting viral spread from cell to cell and that laser therapy acts also on the host immune response unblocking the suppression of proinflammatory mediators induced by accumulation of progeny virus in infected epithelial cells.

Porcine reproductive and respiratory syndrome virus non-structural protein 1 suppresses tumor necrosis factor-alpha promoter activation by inhibiting NF-κB and Sp1

The objective of this study was to identify porcine reproductive and respiratory syndrome virus (PRRSV)-encoded proteins that are responsible for the inhibition of TNF-α expression and the mechanism(s) involved in this phenomenon. Using a TNF-α promoter reporter system, the non-structural protein 1 (Nsp1) was found to strongly suppress the TNF-α promoter activity. Such inhibition takes place especially at the promoter's proximal region. Both Nsp1α and Nsp1β, the two proteolytic fragments of Nsp1, were shown to be involved in TNF-α promoter suppression. Furthermore, using reporter plasmids specific for transcription factors (TFs) that bind to TNF-α promoter, Nsp1α and Nsp1β were demonstrated to inhibit the activity of the TFs that bind CRE-κB(3) and Sp1 elements respectively. Subsequent analyses showed that Nsp1α moderately inhibits NF-κB activation and that Nsp1β completely abrogates the Sp1 transactivation. These findings reveal one of the important mechanisms underlying the innate immune evasion by PRRSV during infection.

Immunomodulatory and antiviral activity of almond skins

The elimination of a viral infection requires a proinflammatory host response (type 1 immunity), characterized by activation of mononuclear cells and production of proinflammatory cytokines, such as interferons (IFNs), tumor necrosis factor (TNF)-alpha and interleukin (IL)-12. On the other hand, IL-4 and IL-10 play a role in decreasing the inflammatory response supported by helper T (Th)1 cells. In this study we evaluated the effects of almond skins on the release of cytokines by peripheral blood mononuclear cells (PBMC), either infected or not with herpes simplex virus type 2 (HSV-2). Natural (NS) and blanched almond skins (BS) were subjected to simulated gastric and duodenal digestion and used at not cytotoxic concentrations. NS induced a significant decrease in HSV-2 replication, whereas extracts obtained from BS did not significantly influence the viral replication. High levels of cytokines production, such as IFN-alpha (38+/-5.3 pg/ml), IL-12 (215+/-17.1 pg/ml), IFN-gamma (5+/-0.7 IU/ml), TNF-alpha (3940+/-201.0 pg/ml), were detected. Moreover, IL-10 (210+/-12.2 pg/ml) and IL-4 (170+/-21.4 pg/ml), representative of Th2 responses, were found. Our data suggest that almond skins improve the immune surveillance of PBMC towards viral infection, both by triggering the Th1 and Th2 subsets.

Activation and evasion of innate antiviral immunity by herpes simplex virus

Herpes simplex virus (HSV), a human pathogenic virus, has evolved several strategies to evade the production and function of interferons (IFNs) and cytokines generated by the innate immune system to restrict the virus. Equilibrium exists between the virus and the immune response, and a shift in this delicate balance either restricts the virus or enhances virus spread and tissue damage. Therefore, understanding of the cytokine response generated after HSV infection and the underlying virus-cell interactions is essential to improve our understanding of viral pathogenesis. This review summarizes the current knowledge on induction and evasion of the innate immune response by HSV.

Pathogen recognition and inflammatory signaling in innate immune defenses

The innate immune system constitutes the first line of defense against invading microbial pathogens and relies on a large family of pattern recognition receptors (PRRs), which detect distinct evolutionarily conserved structures on pathogens, termed pathogen-associated molecular patterns (PAMPs). Among the PRRs, the Toll-like receptors have been studied most extensively. Upon PAMP engagement, PRRs trigger intracellular signaling cascades ultimately culminating in the expression of a variety of proinflammatory molecules, which together orchestrate the early host response to infection, and also is a prerequisite for the subsequent activation and shaping of adaptive immunity. In order to avoid immunopathology, this system is tightly regulated by a number of endogenous molecules that limit the magnitude and duration of the inflammatory response. Moreover, pathogenic microbes have developed sophisticated molecular strategies to subvert host defenses by interfering with molecules involved in inflammatory signaling. This review presents current knowledge on pathogen recognition through different families of PRRs and the increasingly complex signaling pathways responsible for activation of an inflammatory and antimicrobial response. Moreover, medical implications are discussed, including the role of PRRs in primary immunodeficiencies and in the pathogenesis of infectious and autoimmune diseases, as well as the possibilities for translation into clinical and therapeutic applications.

Activation of host antiviral RNA-sensing factors necessary for herpes simplex virus type 1-activated transcription of host cell fucosyltransferase genes FUT3, FUT5, and FUT6 and subsequent expression of sLe(x) in virus-infected cells

Herpes simplex virus type 1 (HSV-1) induces expression of a selectin receptor, the carbohydrate epitope sialyl Lewis X (sLe(x)), at the surface of infected cells. The molecular background to this phenomenon is that a viral immediate early RNA interacts with as yet unidentified host factors, eventually resulting in transcription of three dormant host fucosyltransferase genes (FUT3, FUT5, and FUT6), whose gene products are rate-limiting for synthesis of sLe(x). The aim of the present study was to define the immediate targets for the viral RNA in this process. We found that the Protein Kinase R (PKR) inhibitors 2-aminopurine (2-AP) and C16 inhibited FUT3, FUT5, and FUT6 expression as well as HSV-1-induced expression of sLe(x), indicating a primary role of PKR as a viral RNA target. The PKR-dependent activation of the FUT genes seemed neither to involve PKR effects on translation nor to involve NF-kappaB- or JNK-dependent activation. IMD-0354, known as an inhibitor of the NF-kappaB-activating factor IKK-2, induced FUT transcription via a novel IKK-2-independent mechanism, irrespective of whether the cells were virus-infected or not. Altogether, the results suggested that PKR is the primary target for HSV-1 early RNA during induction of FUT3, FUT5, and FUT6, and that the subsequent steps in the transcriptional activation of these host genes involve a hitherto unknown IMD-0354, yet IKK-2-independent, pathway.

Facile biocatalytic access to 9-fluorenylmethyl polyglycosides: evaluation of antiviral activity on immunocompetent cells

The biological activities of a series of mono- and oligosaccharides (beta-xylosides and alpha-glucosides) of 9-fluorenylmethanol were investigated together with mono-beta-galactoside and beta-glucoside of this aglycone, produced by biocatalytic routes. By using marine glycoside hydrolases and inexpensive donors such as maltose or xylan, access to mono-alpha-glucoside or mono-beta-xyloside of 9-fluorenylmethanol was obtained. Additionally, interesting polyglycoside derivatives were isolated. Biological testing indicated that in vitro treatment with these carbohydrate derivatives may influence the balance of cytokines in the environment of human peripheral blood mononuclear cells (PBMC), restricting the harmful effect of herpes simplex type 2 replication. In fact, these carbohydrate derivatives tested in WISH cells did not show any significant antiviral activity.

The in vitro immunomodulatory activity of a synthetic brassinosteroid analogue would account for the improvement of herpetic stromal keratitis in mice

Herpes simplex virus type 1 (HSV-1) induces an ocular chronic immunoinflammatory syndrome named herpetic stromal keratitis that can lead to vision impairment and blindness. We have reported that the synthetic brassinosteroid (22S,23S)-3beta-bromo-5alpha,22,23-trihydroxystigmastan-6-one, designated as 2, is a potent antiviral in vitro and reduces the incidence of murine herpetic stromal keratitis, although it does not exert an antiviral effect in vivo. In the present report, we investigated whether brassinosteroid 2 may play a role in the modulation of the response of epithelial and immune cells to HSV-1 infection. Compound 2 blocked HSV-1-induced activation of NF-kappaB by inhibiting its translocation to the nucleus of infected corneal and conjunctival cells in vitro, as well as significantly reduced the secretion of TNF-alpha in infected NHC cells. Conversely, IL-6 production was enhanced by compound 2 after HSV-1 infection in both cell types. The production of these cytokines was considerably reduced in a LPS-stimulated macrophage cell line after treatment with compound 2. In conclusion, brassinosteroid 2 would be playing a modulating effect as an inductor or inhibitor, depending on the cell type involved. The improvement of disease observed in mice could be a balance between both, the immunostimulating and immunosuppressive effects of brassinosteroid 2 in vivo.

Amphipathic DNA Polymers are Candidate Vaginal Microbicides and Block Herpes Simplex Virus Binding, Entry and Viral Gene Expression

Background

Amphipathic DNA polymers are promising therapies for the prevention of HIV and genital herpes infections. Recent studies on a panel of such compounds indicated potent activity against HIV binding and entry. This current study was conducted to explore the anti-herpes simplex virus (HSV) activity of the same panel of compounds and to determine their mechanism of activity.

Methods

The anti-HSV activity of a 40-nucleotide degenerate polymer (REP 9), a 40-nucleotide polycytidine amphipathic DNA polymer (REP 9C) and an analogue lacking amphipathic activity (Randomer 3) were compared in plaque reduction assays in the absence or presence of human genital tract secretions; the mechanisms of anti-HSV activity were explored.

Results

REP 9 inhibited HSV infection 10,000-fold, whereas Randomer 3 displayed no anti-HSV activity. The antiviral activity was independent of sequence but was dependent on size: the most potent activity was observed for analogues of 40 nucleotides in length. Mechanistic studies indicated that REP 9 and REP 9C blocked HSV-2 binding and entry, were active when added post-entry, inhibited viral gene expression and blocked HSV-induced apoptosis. Confocal microscopy studies showed rapid delivery of fluorescently tagged REP 9 and REP 9C into human epithelial cells, and delivery was significantly greater in infected cells as compared with uninfected cells. REP 9 exhibited no cytotoxicity and retained anti-HSV activity in the presence of cervicovaginal secretions and when virus was introduced in seminal plasma.

Conclusions

REP 9 and REP 9C represent a novel class of antiviral agents that act by multiple mechanisms. These compounds warrant further development for systemic or topical delivery for the prevention and treatment of HIV and HSV.

Poly I:C inhibits the expression of channel catfish virus immediate-early gene ORF 1 at early times after infection

Channel catfish virus (CCV) is a herpesvirus that infects channel catfish fry and fingerlings. Previous research has demonstrated that Type I interferons inhibit the expression of immediate-early (IE) genes of some mammalian herpesviruses. However, CCV is distantly related to the mammalian herpesviruses and Type I interferons from higher vertebrates exhibit only 20% similarity to fish interferons. In this work we demonstrate that treatment of channel catfish ovary (CCO) cells, a fibroblast-like cell line, with poly I:C, a known inducer of Type I interferons, results in inhibition of expression of the CCV IE gene ORF 1. Thus, although the genes involved have diverged, the mechanism appears to be conserved. If this paradigm holds true for other CCV IE-Type I interferon interactions, it could have important implications for the impact of CCV on the host immune system.

Differential Responses of Murine Vaginal and Uterine Epithelial Cells Prior to and Following Herpes Simplex Virus Type 2 (HSV-2) Infection

PROBLEM

This study was undertaken to evaluate the susceptibility of upper and lower reproductive tract epithelial cells (ECs) to herpes simplex virus type 2 (HSV-2) infection and examine their cytokine secretion patterns prior to and following infection.

METHOD OF STUDY

Primary EC cultures, grown from murine vaginal and uterine tissue, were inoculated with HSV-2. Viral shedding was measured in apical and basolateral compartments. Multi-analyte bead-based immunoassays run on Luminex, were used to analyse cytokine profiles.

RESULTS

Both vaginal and uterine ECs became productively infected with HSV-2, ex-vivo. Uterine ECs displayed varying degrees of infection, dependent on transepithelial resistance of the monolayers. Co-culturing stromal cells did not significantly change levels of viral shedding from ECs. Uterine ECs and epithelial-stromal co-cultures constitutively secreted interleukin (IL)-1alpha, IL-6, mouse homologue of human IL-8 (KC) and monocyte chemotactic protein-1 (MCP-1), while vaginal epithelial-stromal co-cultures secreted granulocyte-macrophage colony stimulating factor (GM-CSF) and KC. Following exposure to HSV-2, IL-6 and MCP-1 levels decreased in uterine EC cultures.

CONCLUSIONS

This data shows that ECs from the upper and lower reproductive tract have different cytokine secretion profiles and respond differentially to infection. HSV-2 may be able to suppress epithelial cytokine secretion as a strategy to evade host immune system.

Human cytomegalovirus blocks tumor necrosis factor alpha- and interleukin-1beta-mediated NF-kappaB signaling

NF-kappaB plays an important role in the early cellular response to pathogens by activating genes involved in inflammation, immune response, and cell proliferation and survival. NF-kappaB is also utilized by many viral pathogens, like human cytomegalovirus (HCMV), to activate their own gene expression programs, reflecting intricate roles for NF-kappaB in both antiviral defense mechanisms and viral physiology. Here we show that the NF-kappaB signaling pathway stimulated by proinflammatory cytokines tumor necrosis factor alpha (TNF-alpha) and interleukin-1beta (IL-1beta) becomes inhibited in HCMV-infected cells. The block to NF-kappaB signaling is first noticeable during the early phase of infection but is fully established only at later times. Biochemical and genetic evidence demonstrates that the viral inhibition of proinflammatory signaling by distinct cytokines occurs upstream of the convergence point of NF-kappaB-activating pathways, i.e., the IkappaB kinase complex, and that it is mediated via different mechanisms. Consistent with this, we further show that an HCMV variant that has lost the ability to downregulate TNF-alpha-induced NF-kappaB signaling also fails to downregulate surface expression of TNF receptor 1, thereby mechanistically linking the inhibition of TNF-alpha-induced NF-kappaB signaling by HCMV to TNF receptor targeting. Our data support a model whereby HCMV inhibits cytokine-induced NF-kappaB signaling at later times during infection, and we suggest that this contributes to the inhibition of the cell's antiviral defense program.

Trypanosoma cruzi-Mediated IFN-γ-Inducible Nitric Oxide Output in Macrophages Is Regulated byiNOSmRNA Stability

Although the effects of activated macrophages (Muphi) on the intracellular parasite Trypanosoma cruzi are well documented, little is known about how host-Muphi functions are affected by this pathogen before activation. This study is aimed at assessing the capacity of T. cruzi infection to modulate J77.4 murine Muphi NO generation following IFN-gamma stimulation, and identifying mechanisms regulating this modulation. Results show that parasite infection potentiates Muphi to produce inducible NO synthase (iNOS) mRNA and protein as well as NO following IFN-gamma stimulation above IFN-gamma alone controls. This potentiation occurs through the concomitant activation of NF-kappaB, ERK1/ERK2 MAPK, and stress-activated protein kinase signaling pathways. Activation of the JAK/STAT pathway by IFN-gamma then leads to STAT1alpha translocation and the transcription of a stable iNOS mRNA species. A decreased rate of iNOS mRNA degradation results in elevated levels of iNOS protein and NO production. Maximal iNOS expression is likely achieved through NF-kappaB activation by T. cruzi, whereas iNOS mRNA stability results from ERK1/ERK2 MAPK and stress-activated protein kinase activation by the infection. Taken together, our data show that T. cruzi-infected Muphi NO generation is controlled at both pre- and posttranscriptional levels and relies on signaling pathway cross-talk. This is the first report of a parasite pathogen capable of heightening host mRNA stability.

Bats: important reservoir hosts of emerging viruses

Bats (order Chiroptera, suborders Megachiroptera ["flying foxes"] and Microchiroptera) are abundant, diverse, and geographically widespread. These mammals provide us with resources, but their importance is minimized and many of their populations and species are at risk, even threatened or endangered. Some of their characteristics (food choices, colonial or solitary nature, population structure, ability to fly, seasonal migration and daily movement patterns, torpor and hibernation, life span, roosting behaviors, ability to echolocate, virus susceptibility) make them exquisitely suitable hosts of viruses and other disease agents. Bats of certain species are well recognized as being capable of transmitting rabies virus, but recent observations of outbreaks and epidemics of newly recognized human and livestock diseases caused by viruses transmitted by various megachiropteran and microchiropteran bats have drawn attention anew to these remarkable mammals. This paper summarizes information regarding chiropteran characteristics and information regarding 66 viruses that have been isolated from bats. From these summaries, it is clear that we do not know enough about bat biology; we are doing too little in terms of bat conservation; and there remain a multitude of questions regarding the role of bats in disease emergence.

Induction of cytokine expression by herpes simplex virus in human monocyte-derived macrophages and dendritic cells is dependent on virus replication and is counteracted by ICP27 targeting NF-kappaB and IRF-3

Macrophages and dendritic cells (DCs) play essential roles in host defence against microbial infections. In the present study, it is shown that human monocyte-derived macrophages and DCs express both type I and type III interferons (IFNs) [IFN-alpha, IFN-beta and interleukin 28 (IL-28), IL-29, respectively], tumour necrosis factor alpha and the chemokines CCL5 and CXCL10 after herpes simplex virus 1 (HSV-1) infection. The cytokine-inducing activity of HSV-1 was dependent on viability of the virus, because UV-inactivated virus did not induce a cytokine response. Pretreatment of the cells with IFN-alpha or IL-29 strongly enhanced the HSV-1-induced cytokine response. Both IFN-alpha and IL-29 decreased viral immediate-early (IE) gene infected-cell protein 27 (ICP27) transcription, suggesting that IL-29 possesses antiviral activity against HSV-1 comparable to that of IFN-alpha. Macrophage infection with HSV-1 lacking functional ICP27 (d27-1 virus) resulted in strongly enhanced cytokine mRNA expression and protein production. In contrast, viruses lacking functional IE genes ICP0 and ICP4 induced cytokine responses comparable to those of the wild-type viruses. The activation of transcription factors IRF-3 and NF-kappaB was strongly augmented when macrophages were infected with the ICP27 mutant virus. Altogether, the results demonstrate that HSV-1 both induces and inhibits the antiviral response in human cells and that the type III IFN IL-29, together with IFN-alpha, amplifies the antiviral response against the virus. It is further identified that viral IE-gene expression interferes with the antiviral response in human macrophages and ICP27 is identified as an important viral protein counteracting the early innate immune response.