Coevolution pays off: Herpesviruses have the license to escape the DNA sensing pathway

Early detection of viral invasion by pattern recognition receptors (PRR) is crucial for the induction of a rapid and efficient immune response. Cytosolic DNA sensors are the most recently described class of PRR, and induce transcription of type I interferons (IFN) and proinflammatory cytokines via the key adaptor protein stimulator of interferon genes (STING). Herpesviruses are a family of large DNA viruses widely known for their immense arsenal of proteins dedicated to manipulating and evading host immune responses. Tantamount to the significant role played by DNA sensors and STING in innate immune responses, herpesviruses have in turn evolved a range of mechanisms targeting virtually every step of this key signaling pathway. Strikingly, some herpesviruses also take advantage of this pathway to promote their own replication. In this review, we will summarize the current understanding of DNA sensing and subsequent induction of signaling and transcription, and showcase the close adaptation of herpesviruses to their host reflected by the myriad of viral proteins dedicated to modulating this critical innate immune pathway.

Comparison of Acyclovir and Multistrain Lactobacillus brevis in Women with Recurrent Genital Herpes Infections: a Double-Blind, Randomized, Controlled Study

We performed a randomized double-blind controlled trial to compare the efficacy and safety of multistrain probiotic and acyclovir in women patients with recurrent genital herpes simplex virus type 2 (HSV-2) infections. Eighty-one patients enrolled in the study were being treated with multistrain Lactobacillus brevis one vaginal capsule every 12 h and oral acyclovir 400 mg twice daily for 6 months. Of 53 patients who completed both treatment courses, no important differences were identified between acyclovir and probiotic for the primary and secondary efficacy endpoint, resolution of episode (hazard ratio, 0.60; 95% CI, 0.3429 to 1.0663; P = 0.08), lesion healing time (hazard ratio, 0.57; 95% CI, 0.3034 to 1.0717, P = 0.08), viral shedding (hazard ratio, 0.54; 95% CI, 0.3027 to 0.9750, P = 0.04), and percentage of pain (hazard ratio, 0.48; 95% CI, 0.2708 to 0.8545, P = 0.01). The median time to first and second recurrence after treatment were 43 and 121 days in patients receiving acyclovir and 33 and 118 days in patients receiving probiotic (HR 2.61; 95% CI, 1.4427 to 4.7546, P = 0.001, and HR 0.62; 95% CI, 0.3500 to 1.1133, P = 0.1, respectively). No clinically important effects happened during the probiotic treatment but some of adverse events reported in patients taking acyclovir. Easy availability, low cost, and no side effect of L. brevis are valuable properties of probiotic therapy compared with acyclovir. Therefore, we concluded that multistrain L. brevis could play an important role in suppression of recurrent genital herpes simplex virus infection.

Increased Frequency of Virus Shedding by Herpes Simplex Virus 2-Infected Guinea Pigs in the Absence of CD4+ T Lymphocytes

Reactivation of herpes simplex virus 2 (HSV-2) results in infection of epithelial cells at the neuro-epithelial junction and shedding of virus at the epithelial surface. Virus shedding can occur in either the presence or absence of clinical disease and is usually of short duration, although the shedding frequency varies among individuals. The basis for host control of virus shedding is not well understood, although adaptive immune mechanisms are thought to play a central role. To determine the importance of CD4⁺ T cells in control of HSV-2 shedding, this subset of immune cells was depleted from HSV-2-infected guinea pigs by injection of an anti-CD4 monoclonal antibody (MAb). Guinea pigs were treated with the depleting MAb after establishment of a latent infection, and vaginal swabs were taken daily to monitor shedding by quantitative PCR. The cumulative number of HSV-2 shedding days and the mean number of days virus was shed were significantly increased in CD4-depleted compared to control-treated animals. However, there was no difference in the incidence of recurrent disease between the two treatment groups. Serum antibody levels and the number of HSV-specific antibody-secreting cells in secondary lymphoid tissues were unaffected by depletion of CD4⁺ T cells; however, the frequency of functional HSV-specific, CD8⁺ gamma interferon-secreting cells was significantly decreased. Together, these results demonstrate an important role for CD4⁺ T lymphocytes in control of virus shedding that may be mediated in part by maintenance of HSV-specific CD8⁺ T cell populations. These results have important implications for development of therapeutic vaccines designed to control HSV-2 shedding.IMPORTANCE Sexual transmission of HSV-2 results from viral shedding following reactivation from latency. The immune cell populations and mechanisms that control HSV-2 shedding are not well understood. This study examined the role of CD4⁺ T cells in control of virus shedding using a guinea pig model of genital HSV-2 infection that recapitulates the shedding of virus experienced by humans. We found that the frequency of virus-shedding episodes, but not the incidence of clinical disease, was increased by depletion of CD4⁺ T cells. The HSV-specific antibody response was not diminished, but frequency of functional HSV-reactive CD8⁺ T cells was significantly diminished by CD4 depletion. These results confirm the role of cell-mediated immunity and highlight the importance of CD4⁺ T cells in controlling HSV shedding, suggesting that therapeutic vaccines designed to reduce transmission by controlling HSV shedding should include specific enhancement of HSV-specific CD4⁺ T cell responses.

Histidine-Rich Glycoprotein Inhibits HIV-1 Infection in a pH-Dependent Manner

Histidine-rich glycoprotein (HRG) is an abundant plasma protein with a multidomain structure, allowing its interaction with many ligands, including phospholipids, plasminogen, fibrinogen, IgG antibodies, and heparan sulfate. HRG has been shown to regulate different biological responses, such as angiogenesis, coagulation, and fibrinolysis. Here, we found that HRG almost completely abrogated the infection of Ghost cells, Jurkat cells, CD4⁺ T cells, and macrophages by HIV-1 at a low pH (range, 6.5 to 5.5) but not at a neutral pH. HRG was shown to interact with the heparan sulfate expressed by target cells, inhibiting an early postbinding step associated with HIV-1 infection. More importantly, by acting on the viral particle itself, HRG induced a deleterious effect, which reduces viral infectivity. Because cervicovaginal secretions in healthy women show low pH values, even after semen deposition, our observations suggest that HRG might represent a constitutive defense mechanism in the vaginal mucosa. Of note, low pH also enabled HRG to inhibit the infection of HEp-2 cells and Vero cells by respiratory syncytial virus (RSV) and herpes simplex virus 2 (HSV-2), respectively, suggesting that HRG might display broad antiviral activity under acidic conditions.IMPORTANCE Vaginal intercourse represents a high-risk route for HIV-1 transmission. The efficiency of male-to-female HIV-1 transmission has been estimated to be 1 in every 1,000 episodes of sexual intercourse, reflecting the high degree of protection conferred by the genital mucosa. However, the contribution of different host factors to the protection against HIV-1 at mucosal surfaces remains poorly defined. Here, we report for the first time that acidic values of pH enable the plasma protein histidine-rich glycoprotein (HRG) to strongly inhibit HIV-1 infection. Because cervicovaginal secretions usually show low pH values, our observations suggest that HRG might represent a constitutive antiviral mechanism in the vaginal mucosa. Interestingly, infection by other viruses, such as respiratory syncytial virus and herpes simplex virus 2, was also markedly inhibited by HRG at low pH values, suggesting that extracellular acidosis enables HRG to display broad antiviral activity.

Performance of four diagnostic assays for detecting herpes simplex virus type 2 antibodies in the Middle East and North Africa

BACKGROUND

Assessments of commercial assays in detecting herpes simplex virus type 2 (HSV-2) antibodies have shown variable sensitivity and specificity, and variation in performance by global population.

OBJECTIVE

To evaluate performance of four assays in detecting HSV-2 antibodies in a composite Middle Eastern and North African (MENA) population. The assays are two ELISA kits: HerpeSelect^® 2 ELISA IgG and Euroimmun Anti-HSV-2 (gG2) ELISA (IgG), and two immunoblot (IB)/Western blot (WB) assays: HerpeSelect^® 1 and 2 Immunoblot IgG and Euroimmun Anti-HSV-1/HSV-2 gG2 Euroline-WB (IgG/IgM).

STUDY DESIGN

Blood specimens were drawn from blood donors between 2013-2016 in Doha, Qatar. Twenty specimens from ten nationalities (Egypt, Iran, Jordan, Lebanon, Pakistan, Palestine, Qatar, Sudan, Syria, and Yemen; total = 200) were randomly selected and tested for HSV-2 antibodies.

RESULTS

In the six possible assay comparisons, Cohen's kappa statistics indicated fair to good agreement, ranging between 0.57 (95% CI 0.28-0.86) and 0.69 (95% CI 0.44-0.95). Meanwhile, positive percent agreement ranged between 50.0 (95% CI 18.7-81.3%) and 63.6% (95% CI 30.8-89.1%); negative percent agreement ranged between 97.8% (95% CI 94.4-99.4%) and 99.5% (95% CI 97.0-100.0%); and overall percent agreement ranged between 95.8% (95% CI 91.9-97.9%) and 97.5% (95% CI 94.2-98.9%). The two ELISA kits demonstrated comparable sensitivities and specificities ≥50% and >98%, respectively, with respect to the IB/WB assays.

CONCLUSION

The study provided, for the first time, primary data on performance of these assays in diagnosing HSV-2 infection in MENA populations. Findings support comparable performance and utility of these assays, and demonstrate challenges in establishing seropositivity (versus seronegativity).

The antiviral activity of arbidol hydrochloride against herpes simplex virus type II (HSV-2) in a mouse model of vaginitis

Objective

HSV-2 infection has increased significantly in recent years, which is closely associated with cervical cancer and HIV infection. The lack of success in vaccine development and the emergence of drug resistance to commonly used drugs emphasize the urgent need for alternative antivirals against HSV-2 infection. Arbidol (ARB) has been demonstrated to be a broad spectrum antiviral drug that exhibits immunomodulatory properties that affect the HSV-2 life cycle. This study investigated the efficacy and mechanism of ARB against HSV-2 in vivo and in vitro to further explore the clinical application of ARB.

Methods

The efficacy of ARB on HSV-2 infection in vitro was examined by CPE and MTT assays. A vaginitis model was established to monitor changes in histopathology and inflammatory cytokine (IL-2, IL-4, TNF-α and TGF-β) expression by H&E staining and ELISA, respectively, and the efficacy of ARB was evaluated accordingly. Furthermore, flow cytometry was used to determine the ratio of CD4⁺/CD8⁺ T cells in the peripheral blood of the vaginitis animals. Considering the balance of efficacy and pharmacokinetics, ARB ointment was strictly prepared to observe formulation efficacy differences compared to the oral dosing form.

Results

The results showed that, in vitro, the TC₅₀ and IC₅₀ of ARB were 32.32 μg/mL and 4.77 μg/mL (SI = 6.82), respectively, indicating that ARB presents effective activity against HSV-2 in a dose-dependent manner. The results of the time-course assay suggested that 25 μg/mL ARB affected the late stage of HSV-2 replication. However, ARB did not inhibit viral attachment or cell penetration. The in vivo results showed that ARB ointment can improve the survival rate, prolong the survival time and reduce the reproductive tract injury in mice infected with HSV-2, regulate cytokine expression; and balance the CD4⁺ and CD8⁺ T lymphocyte ratio in the peripheral blood to participate in the regulation of immune response.

Conclusion

ARB showed anti-HSV-2 activity in vitro in a dose-dependent manner and played a role in inhibiting the late replication cycle of the virus. The vaginitis model was successfully established, according to immunomodulation outcomes, responded better to ARB in ointment form than in oral form.

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ARB showed anti-HSV-2 activity in vitro in a dose-dependent manner.

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ARB inhibited the late replication cycle of HSV-2.

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ARB ointment participated in the regulation of immune response to reduce the reproductive tract injury.

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ARB in ointment form responded to vaginitis better than in oral form.

Behavioral, Psychological, Gender, and Health Service Correlates to Herpes Simplex Virus Type 2 Infection among Young Adult Mexican-American Women Living in a Disadvantaged Community

Herpes simplex virus type 2 (HSV-2) is among the most prevalent sexually transmitted infections in the United States. Despite this, there has been limited research on the correlates to HSV-2 among disadvantaged and marginalized women, particularly among Latinas. Data for the present analysis include 125 young adult Mexican-American women enrolled in a longitudinal study in a disadvantaged urban community in San Antonio, Texas. The current rate of tested HSV-2 infection is 56.8%. Our findings suggest strong comorbidity of genital herpes with injecting heroin use, Hepatitis C, sexual violence, incarceration, and mental illness. Contributing to this population's nexus of risk are the low rates of health service utilization among those infected with HSV-2. Integration between behavioral health and primary care, including access to preventative services, are essential for improving the health of Latinas living in disadvantaged neighborhoods.

Herpes Simplex Virus Type 2 Infection-Induced Expression of CXCR3 Ligands Promotes CD4+ T Cell Migration and Is Regulated by the Viral Immediate-Early Protein ICP4

HSV-2 infection-induced CXCR3 ligands are important for the recruitment of virus-specific CD8⁺ T cells, but their impact on CD4⁺ T cell trafficking remains to be further determined. Given that recruitment of CD4⁺ T cells to infection areas may be one of the mechanisms that account for HSV-2 infection-mediated enhancement of HIV-1 sexual transmission, here we investigated the functionality of HSV-2 infection-induced CXCR3 ligands CXCL9, CXCL10, and CXCL11 in vivo and in vitro, and determined the viral components responsive for such induction and the underlying mechanisms. We first found that the expression of CXCR3 ligands CXCL9, CXCL10, and CXCL11 was increased in mice following vaginal challenge with HSV-2, while CXCL9 played a predominant role in the recruitment of CD4⁺ T cells to the vaginal foci of infected mice. HSV-2 infection also induced the production of CXCL9, CXCL10, and CXCL11 in human cervical epithelial cells. Of note, although HSV-2 induced the expression of all the three CXCR3 ligands, the induced CXCL9 appeared to play a predominant role in promoting CD4⁺ T cell migration, reflecting that the concentrations of CXCL10 and CXCL11 required for CD4⁺ T cell migration are higher than that of CXCL9. We further revealed that, ICP4, an immediate-early protein of HSV-2, is crucial in promoting CXCR3 ligand expression through the activation of p38 MAPK pathway. Mechanistically, ICP4 binds to corresponding promoters of CXCR3 ligands via interacting with the TATA binding protein (TBP), resulting in the transcriptional activation of the corresponding promoters. Taken together, our study highlights HSV-2 ICP4 as a vital viral protein in promoting CXCR3 ligand expression and CXCL9 as the key induced chemokine in mediating CD4⁺ T cell migration. Findings in this study have shed light on HSV-2 induced leukocyte recruitment which may be important for understanding HSV-2 infection-enhanced HIV-1 sexual transmission and the development of intervention strategies.

Host Enzymes Heparanase and Cathepsin L Promote Herpes Simplex Virus 2 Release from Cells

Herpes simplex virus 2 (HSV-2) can productively infect many different cell types of human and nonhuman origin. Here we demonstrate interconnected roles for two host enzymes, heparanase (HPSE) and cathepsin L, in HSV-2 release from cells. In vaginal epithelial cells, HSV-2 causes heparan sulfate shedding and upregulation in HPSE levels during the productive phase of infection. We also noted increased levels of cathepsin L and show that regulation of HPSE by cathepsin L via cleavage of HPSE proenzyme is important for infection. Furthermore, inhibition of HPSE by a specific inhibitor, OGT 2115, dramatically reduces HSV-2 release from vaginal epithelial cells. Likewise, we show evidence that the inhibition of cathepsin L is detrimental to the infection. The HPSE increase after infection is mediated by an increased NF-κB nuclear localization and a resultant activation of HPSE transcription. Together these mechanisms contribute to the removal of heparan sulfate from the cell surface and thus facilitate virus release from cells.IMPORTANCE Genital infections by HSV-2 represent one of the most common sexually transmitted viral infections. The virus causes painful lesions and sores around the genitals or rectum. Intermittent release of the virus from infected tissues during sexual activities is the most common cause of transmission. At the molecular level, cell surface heparan sulfate (HS) is known to provide attachment sites for HSV-2. While the removal of HS during HSV-1 release has been shown, not much is known about the host factors and their regulators that contribute to HSV-2 release from natural target cell types. Here we suggest a role for the host enzyme heparanase in HSV-2 release. Our work reveals that in addition to the regulation of transcription by NF-κB, HPSE is also regulated posttranslationally by cathepsin L and that inhibition of heparanase activity directly affects HSV-2 release. We provide unique insights into the host mechanisms controlling HSV-2 egress and spread.

Prevalence of sexually transmitted infections (HIV, hepatitis B virus, herpes simplex virus type 2, and syphilis) in pregnant women in Ethiopia: Trends over 10 years (2005-2014)

OBJECTIVES

This study was performed to determine the trends in seroprevalence of four major sexually transmitted infections (STIs) (HIV, hepatitis B virus (HBV), herpes simplex virus type 2 (HSV-2), and syphilis) over a 10-year period (2005-2014) in pregnant women in Ethiopia.

METHODS

Pregnant women (15-49 years old) who were enrolled in the antenatal care-based national HIV surveillance were included. Serological tests for HIV, HBV, HSV-2, and syphilis were done on serum/plasma samples.

RESULTS

A total of 4887 pregnant women were included. Results showed a decline in prevalence of these STIs by 40-60% over the 10 years (2005-2014): HIV (10.5% to 5.5%), syphilis (2.5% to 1.1%), HBV (12.6% to 6.7%), and HSV-2 (47.5% to 28.5%). In 2014, 109/4887 (2.2%) women had triple infections. In 2005, 2007, and 2009, the prevalence of HSV-2 in the older age group (35-45 years) (47.1%, 47.4%, and 50.0%, respectively) was higher than that in the younger age group (15-24 years) (40.9%, 19.5%, and 20.2%, respectively). Age category (Chi-square=22.4, p<0.001), study sites/residence (Chi-square=135.2, p=0.001), and time/years (Chi-square=58.9, p=0.001) were associated with a positive HSV-2 test result.

CONCLUSIONS

A decline in HIV, HBV, HSV-2, and syphilis of >40% was seen over the years in Ethiopia. However, an intermediate endemicity level of HBV and higher prevalence of HIV and HSV-2 by 2014, suggest the need to strengthen prevention strategy for STIs.

Herpetic Panophthalmitis: A Diagnostic Dilemma

Purpose: To describe an uncommon presentation of ocular infection caused by human herpes simplex virus 2 (HSV-2).Methods: Case report.Results: A 32-year-old female with no prior history of mucocutaneous herpesvirus infection presented with a minimally painful hypertensive granulomatous panophthalmitis and optic neuropathy that was initially suspected to be orbital cellulitis. Her disease progressed despite antibiotic and steroid treatment, and HSV-2 was ultimately identified in the vitreous.Conclusion: Although rare, ocular infection by human herpesvirus can present as a panophthalmitis. The case is discussed in the context of two previously reported cases of herpes simplex panophthalmitis, as well panophthalmitis caused by varicella zoster virus.

Development of disease and immunity at the genital epithelium following intrarectal inoculation of male guinea pigs with herpes simplex virus type 2

Most analyses of genital immunity to herpes simplex virus type 2 (HSV-2) have been performed in females, consequently immune protection of the male genital epithelium is incompletely understood. We developed a model of male genital HSV-2 infection resulting from intrarectal inoculation of guinea pigs. Vesicular lesions developed transiently on the perineum and foreskin concurrent with acute virus shedding. Virus shedding and recurrent genital lesions were also detected after establishment of a latent infection. Analysis of perineum and foreskin RNA detected transcripts for IFNγ, proinflammatory and regulatory cytokines, and for genes involved in migration and regulation of leukocytes. HSV-specific T cells were detected in lymphoid and genital tissues after resolution of the primary infection whereas virus-specific antibody secreting cells were detected only in lymphoid tissue. Taken together, the ability to quantify pathogenesis and local immunity in this guinea pig model represent an important advance towards understanding immunity to HSV-2 in males.

Clinical management of herpes simplex virus infections: past, present, and future

Infection with herpes simplex virus (HSV) types 1 and 2 is ubiquitous in the human population. Most commonly, virus replication is limited to the epithelia and establishes latency in enervating sensory neurons, reactivating periodically to produce localized recurrent lesions. However, these viruses can also cause severe disease such as recurrent keratitis leading potentially to blindness, as well as encephalitis, and systemic disease in neonates and immunocompromised patients. Although antiviral therapy has allowed continual and substantial improvement in the management of both primary and recurrent infections, resistance to currently available drugs and long-term toxicity pose a current and future threat that should be addressed through the development of new antiviral compounds directed against new targets. The development of several promising HSV vaccines has been terminated recently because of modest or controversial therapeutic effects in humans. Nevertheless, several exciting vaccine candidates remain in the pipeline and are effective in animal models; these must also be tested in humans for sufficient therapeutic effects to warrant continued development. Approaches using compounds that modulate the chromatin state of the viral genome to suppress infection and reactivation or induce enhanced antiviral immunity have potential. In addition, technologies such as CRISPR/Cas9 have the potential to edit latent viral DNA in sensory neurons, potentially curing the neuron and patient of latent infection. It is hoped that development on all three fronts—antivirals, vaccines, and gene editing—will lead to substantially less HSV morbidity in the future.

Photodynamic Inactivation of Herpes Simplex Viruses

Herpes simplex virus (HSV) infections can be treated with direct acting antivirals like acyclovir and foscarnet, but long-term use can lead to drug resistance, which motivates research into broadly-acting antivirals that can provide a greater genetic barrier to resistance. Photodynamic inactivation (PDI) employs a photosensitizer, light, and oxygen to create a local burst of reactive oxygen species that inactivate microorganisms. The botanical plant extract Orthoquin^TM is a powerful photosensitizer with antimicrobial properties. Here we report that Orthoquin also has antiviral properties. Photoactivated Orthoquin inhibited herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2) infection of target cells in a dose-dependent manner across a broad range of sub-cytotoxic concentrations. HSV inactivation required direct contact between Orthoquin and the inoculum, whereas pre-treatment of target cells had no effect. Orthoquin did not cause appreciable damage to viral capsids or premature release of viral genomes, as measured by qPCR for the HSV-1 genome. By contrast, immunoblotting for HSV-1 antigens in purified virion preparations suggested that higher doses of Orthoquin had a physical impact on certain HSV-1 proteins that altered protein mobility or antigen detection. Orthoquin PDI also inhibited the non-enveloped adenovirus (AdV) in a dose-dependent manner, whereas Orthoquin-mediated inhibition of the enveloped vesicular stomatitis virus (VSV) was light-independent. Together, these findings suggest that the broad antiviral effects of Orthoquin-mediated PDI may stem from damage to viral attachment proteins.

Antiviral Activity of Tannic Acid Modified Silver Nanoparticles: Potential to Activate Immune Response in Herpes Genitalis

(1) Background: Tannic acid is a plant-derived polyphenol showing antiviral activity mainly because of an interference with the viral adsorption. In this work, we tested whether the modification of silver nanoparticles with tannic acid (TA-AgNPs) can provide a microbicide with additional adjuvant properties to treat genital herpes infection. (2) Methods: The mouse model of the vaginal herpes simplex virus 2 (HSV-2) infection was used to test immune responses after treatment of the primary infection with TA-AgNPs, and later, after a re-challenge with the virus. (3) Results: The mice treated intravaginally with TA-AgNPs showed better clinical scores and lower virus titers in the vaginal tissues soon after treatment. Following a re-challenge, the vaginal tissues treated with TA-AgNPs showed a significant increase in the percentages of IFN-gamma+ CD8+ T-cells, activated B cells, and plasma cells, while the spleens contained significantly higher percentages of IFN-gamma+ NK cells and effector-memory CD8+ T cells in comparison to NaCl-treated group. TA-AgNPs-treated animals also showed significantly better titers of anti-HSV-2 neutralization antibodies in sera; and (4) Conclusions: Our findings suggest that TA-AgNPs sized 33 nm can be an effective anti-viral microbicide to be applied upon the mucosal tissues with additional adjuvant properties enhancing an anti-HSV-2 immune response following secondary challenge.

HSV-2 glycoprotein J promotes viral protein expression and virus spread

HSV-2 spread is predominantly dependent on cell-to-cell contact. However, the underlying mechanisms remain to be determined. Here we demonstrate that HSV-2 gJ, which was previously assigned no specific function, promotes HSV-2 cell-to-cell spread and syncytia formation. In the context of viral infection, knockout or knockdown of gJ impairs HSV-2 cell-to-cell spread among epithelial cells or from epithelial cells to neuronal cells, which leads to decreased virus production, whereas ectopic expression of gJ enhances virus production. Mechanistically, gJ increases the expression levels of HSV-2 proteins, and also enhances viral protein expression and replication of heterologous viruses like HIV-1 and JEV, suggesting that HSV-2 gJ likely functions as a regulator of viral protein expression and virus production. Findings in this study provide a basis for further understanding the role of gJ in HSV-2 replication.

In Vitro Study of Multi-Therapeutic Properties of Thymus bovei Benth. Essential Oil and Its Main Component for Promoting Their Use in Clinical Practice

Thymus bovei Benth. (TB) is an important plant in the traditional medicine of the Mediterranean region. This study investigates the health-promoting properties of TB essential oil (TB-EO) for its possible use in clinical practice with regards to its cytotoxic, anti-herpes simplex virus type 2 (HSV-2), and antihypertensive (through inhibition of human angiotensin-converting enzyme; ACE) properties. The phytochemical profile of EO (99.9%) was analyzed by Gas Chromatography with Flame-Ionization Detection (GC-FID) and Gas Chromatography-Mass Spectrometry (GC-MS). In this study, all biological methods were performed at the level of in vitro studies. The results showed that TB-EO exerted remarked cytotoxic properties against human cervical carcinoma cells, colon cancer cells, and lung adenocarcinoma cells with the half-maximal inhibitory concentration (IC₅₀) values of 7.22, 9.30, and 8.62 µg/mL, respectively, in comparison with that of standard anticancer drug cisplatin with IC₅₀ values of 4.24, 5.21, and 5.43 µg/mL, respectively. Fascinatingly, TB-EO showed very weak cytotoxicity on the healthy human fetal lung fibroblast cells with an IC₅₀ value of 118.34 µg/mL compared with that of cisplatin (IC₅₀ = 10.08 µg/mL). TB-EO, its main component geraniol, TB-EO combined with acyclovir (ACV) along with standard ACV, have displayed pronounced inhibitory properties against the replication of HSV-2 with the half-maximal effective concentration (EC₅₀) values of 2.13, 1.92, 0.81 and 1.94 µg/mL, respectively, with corresponding selectivity indices (SI) 98.59, 109.38, 259.26 and 108.25, respectively. TB-EO and geraniol at a concentration of 15 µg/mL showed prominent inhibitory activities against ACE with % of inhibition 95.4% and 92.2%, respectively, compared with that of standard inhibitor captopril (99.8%; 15 µg/mL). Molecular docking studies were performed to unveil the mechanism of action of geraniol as well as structural parameters necessary for anti-HSV-2 activity (through the inhibition of HSV-2 protease) and ACE inhibition. This is the first report on the chemical composition of Egyptian TB-EO along with the above-mentioned biological activities. Our results may be considered as novel findings in the course of a search for new and active anticancer, anti-HSV-2 and antihypertensive agents, and expand the medicinal value of this plant and its phytochemicals in clinical practice.

Resveratrol as a Novel Anti-Herpes Simplex Virus Nutraceutical Agent: An Overview

The herpes simplex virus (HSV) is a common human virus affecting many people worldwide. HSV infections manifest with lesions that occur in different parts of the body, including oral, ocular, nasal, and genital skin and mucosa. In rare cases, HSV infections can be serious and lethal. Several anti-HSV drugs have been developed, but the existence of mutant viruses resistant to these drugs led to the individuation of novel antiviral agents. Plant-derived bioactive compounds, and more specifically polyphenols, have been demonstrated to exert marked anti-HSV activity and, among these, resveratrol (RSV) would be considered a good candidate. The purpose of this manuscript is to review the available literature elucidating the efficacy of RSV against HSV and the main demonstrated mechanisms of action.

Regulation of Herpes Simplex Virus 2 Protein Kinase UL13 by Phosphorylation and Its Role in Viral Pathogenesis

UL13 proteins are serine/threonine protein kinases encoded by herpes simplex virus 1 (HSV-1) and HSV-2. Although the downstream effects of the HSV protein kinases, mostly those of HSV-1 UL13, have been reported, there is a lack of information on how these viral protein kinases are regulated in HSV-infected cells. In this study, we used a large-scale phosphoproteomic analysis of HSV-2-infected cells to identify a physiological phosphorylation site in HSV-2 UL13 (i.e., Ser-18) and investigated the significance of phosphorylation of this site in HSV-2-infected cell cultures and mice. Our results were as follows. (i) An alanine substitution at UL13 Ser-18 (S18A) significantly reduced HSV-2 replication and cell-to-cell spread in U2OS cells to a level similar to those of the UL13-null and kinase-dead mutations. (ii) The UL13 S18A mutation significantly impaired phosphorylation of a cellular substrate of this viral protein kinase in HSV-2-infected U2OS cells. (iii) Following vaginal infection of mice, the UL13 S18A mutation significantly reduced mortality, HSV-2 replication in the vagina, and development of vaginal disease to levels similar to those of the UL13-null and the kinase-dead mutations. (iv) A phosphomimetic substitution at UL13 Ser-18 significantly restored the phenotype observed with the UL13 S18A mutation in U2OS cells and mice. Collectively, our results suggested that phosphorylation of UL13 Ser-18 regulated UL13 function in HSV-2-infected cells and that this regulation was critical for the functional activity of HSV-2 UL13 in vitro and in vivo and also for HSV-2 replication and pathogenesis.IMPORTANCE Based on studies on cellular protein kinases, it is obvious that the regulatory mechanisms of protein kinases are as crucial as their functional consequences. Herpesviruses each encode at least one protein kinase, but the mechanism by which these kinases are regulated in infected cells remains to be elucidated, with a few exceptions, although information on their functional effects has been accumulating. In this study, we have shown that phosphorylation of the HSV-2 UL13 protein kinase at Ser-18 regulated its function in infected cells, and this regulation was critical for HSV-2 replication and pathogenesis in vivo UL13 is conserved in all members of the family Herpesviridae, and this is the first report clarifying the regulatory mechanism of a conserved herpesvirus protein kinase that is involved in viral replication and pathogenesis in vivo Our study may provide insight into the regulatory mechanisms of the other conserved herpesvirus protein kinases.

Anti-Infectivity against Herpes Simplex Virus and Selected Microbes and Anti-Inflammatory Activities of Compounds Isolated from Eucalyptus globulus Labill

Herpes simplex virus (HSV) causes numerous mild-to-serious human diseases, including mucocutaneous herpes infections and life-threatening herpes encephalitis. Moreover, herpes viral lesions can be complicated by inflammation and secondary bacterial infections. The development of resistance to antiviral drugs along with the undesirable side effects of these drugs are relevant argue for the development of new anti-HSV drugs with diverse mechanisms of action. Eucalyptus extracts have been used for decades to combat various infectious diseases. We isolated and studied 12 pure compounds and one mixture of two constitutional isomers from the leaves and twigs of E. globulus. The structures were identified by spectroscopic methods (NMR, HR-MS, IR) and all of them were tested for antiherpetic activity against the replication of antigen types HSV-1 and HSV-2. Tereticornate A (12) (IC₅₀: 0.96 μg/mL; selectivity index CC₅₀/IC₅₀: 218.8) showed the strongest activity in the anti-HSV-1 assay, even greater than acyclovir (IC₅₀: 1.92 μg/mL; selectivity index CC₅₀/IC₅₀: 109.4), a standard antiviral drug. Cypellocarpin C (5) (EC₅₀: 0.73 μg/mL; selectivity index CC₅₀/EC₅₀: 287.7) showed the most potent anti-HSV-2 activity, also more intensive than acyclovir (EC₅₀: 1.75 μg/mL; selectivity index CC₅₀/EC₅₀: 120.0). The antimicrobial activity of the isolated compounds was also evaluated against the bacteria Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Pseudomonas aeruginosa and the yeast Candida albicans. The anti-inflammatory potential was examined using LPS-stimulated THP-1-XBlue™-MD2-CD14 and THP-1 macrophages and focusing on the influences of the NF-κB/AP-1 activity and the secretion of pro-inflammatory cytokines IL-1β and TNF-α.

Ultrasensitive Capture of Human Herpes Simplex Virus Genomes Directly from Clinical Samples Reveals Extraordinarily Limited Evolution in Cell Culture

Herpes simplex viruses (HSVs) are difficult to sequence due to their large DNA genome, high GC content, and the presence of repeats. To date, most HSV genomes have been recovered from culture isolates, raising concern that these genomes may not accurately represent circulating clinical strains. We report the development and validation of a DNA oligonucleotide hybridization panel to recover nearly complete HSV genomes at abundances up to 50,000-fold lower than previously reported. Using copy number information on herpesvirus and host DNA background via quantitative PCR, we developed a protocol for pooling for cost-effective recovery of more than 50 HSV-1 or HSV-2 genomes per MiSeq run. We demonstrate the ability to recover >99% of the HSV genome at >100× coverage in 72 h at viral loads that allow whole-genome recovery from latently infected ganglia. We also report a new computational pipeline for rapid HSV genome assembly and annotation. Using the above tools and a series of 17 HSV-1-positive clinical swabs sent to our laboratory for viral isolation, we show limited evolution of HSV-1 during viral isolation in human fibroblast cells compared to the original clinical samples. Our data indicate that previous studies using low-passage-number clinical isolates of herpes simplex viruses are reflective of the viral sequences present in the lesion and thus can be used in phylogenetic analyses. We also detect superinfection within a single sample with unrelated HSV-1 strains recovered from separate oral lesions in an immunosuppressed patient during a 2.5-week period, illustrating the power of direct-from-specimen sequencing of HSV.IMPORTANCE Herpes simplex viruses affect more than 4 billion people across the globe, constituting a large burden of disease. Understanding the global diversity of herpes simplex viruses is important for diagnostics and therapeutics as well as cure research and tracking transmission among humans. To date, most HSV genomics has been performed on culture isolates and DNA swabs with high quantities of virus. We describe the development of wet-lab and computational tools that enable the accurate sequencing of near-complete genomes of HSV-1 and HSV-2 directly from clinical specimens at abundances >50,000-fold lower than previously sequenced and at significantly reduced cost. We use these tools to profile circulating HSV-1 strains in the community and illustrate limited changes to the viral genome during the viral isolation process. These techniques enable cost-effective, rapid sequencing of HSV-1 and HSV-2 genomes that will help enable improved detection, surveillance, and control of this human pathogen.

Infectivity and growth kinetics of Herpes Simplex Virus type-2 in MOLT4 CCR5+ and CEM CCR5+ T cell lines

Herpes simplex virus type-2 (HSV-2) is an important sexually transmitted pathogen that infects the genital mucosal epithelial cells causing ulcerative lesions at the site of entry, facilitating HIV infection. The infection of epithelial cells and skin resident dendritic cells with HSV-2 causes a release of chemokine and retinoic acid which attracts CD4⁺ T-cells to the genital mucosa. In this study, we investigated whether HSV-2 (ATCC VR734) could infect and replicate in two T-cell lines (CEM CCR5+ and MOLT4 CCR5+). The growth of HSV-2 was assessed by plaque assay while the intracellular HSV-2 was identified using infectious center and indirect immunofluorescence assays. The replication of HSV-2 in T-cell lines was compared to a cell line (Vero) which is routinely used for growing HSV-2. Analysis indicated that a low level of infection was detected in the two T-cells lines and was dependent on the infectious dose as well as the time of adsorption. Indirect immunofluorescence showed presence of HSV-2 antigens in the CEM CCR5+ and Vero cell lines but not in MOLT4 CCR5+. The data suggests that T-cells can support growth of HSV-2 which might contribute to changes in gene expression of T-cells. This is an important aspect that needs to be further investigated in relation of HIV-1/HSV-2 viral synergy.

Tannic Acid-Modified Silver and Gold Nanoparticles as Novel Stimulators of Dendritic Cells Activation

Silver nanoparticles (AgNPs) are promising new antimicrobial agents against a wide range of skin and mucosal pathogens. However, their interaction with the immune system is currently not fully understood. Dendritic cells (DCs) are crucial during development of T cell-specific responses against bacterial and viral pathogens. We have previously shown that tannic acid-modified silver nanoparticles (TA-AgNPs) consist of a promising microbicide against HSV-2. The aim of this study was to compare the ability of TA-AgNPs or TA-AuNPs of similar sizes (TA-Ag/AuNPs) to induce DCs maturation and activation in the presence of HSV-2 antigens when used at non-toxic doses. First, we used JAWS II DC line to test toxicity, ultrastructure as well as activation markers (MHC I and II, CD40, CD80, CD86, PD-L1) and cytokine production in the presence of TA-Ag/AuNPs. Preparations of HSV-2 treated with nanoparticles (TA-Ag/AuNPs-HSV-2) were further used to investigate HSV-2 antigen uptake, activation markers, TLR9 expression, and cytokine production. Additionally, we accessed proliferation and activation of HSV-2-specific T cells by DCs treated with TA-AgNP/AuNPs-HSV-2. We found that both TA-AgNPs and TA-AuNPs were efficiently internalized by DCs and induced activated ultrastructure. Although TA-AgNPs were more toxic than TA-AuNPs in corresponding sizes, they were also more potent stimulators of DCs maturation and TLR9 expression. TA-Ag/AuNPs-HSV-2 helped to overcome inhibition of DCs maturation by live or inactivated virus through up-regulation of MHC II and CD86 and down-regulation of CD80 expression. Down-regulation of CD40 expression in HSV-2-infected DCs was reversed when HSV-2 was treated with TA-NPs sized >30 nm. On the other hand, small-sized TA-AgNPs helped to better internalize HSV-2 antigens. HSV-2 treated with both types of NPs stimulated activation of JAWS II and memory CD8+ T cells, while TA-AgNPs treatment induced IFN-γ producing CD4+ and CD8+ T cells. Our study shows that TA-AgNPs or TA-AuNPs are good activators of DCs, albeit their final effect upon maturation and activation may be metal and size dependent. We conclude that TA-Ag/AuNPs consist of a novel class of nano-adjuvants, which can help to overcome virus-induced suppression of DCs activation.

A VP26-mNeonGreen Capsid Fusion HSV-2 Mutant Reactivates from Viral Latency in the Guinea Pig Genital Model with Normal Kinetics

Fluorescent herpes simplex viruses (HSV) are invaluable tools for localizing virus in cells, permitting visualization of capsid trafficking and enhancing neuroanatomical research. Fluorescent viruses can also be used to study virus kinetics and reactivation in vivo. Such studies would be facilitated by fluorescent herpes simplex virus recombinants that exhibit wild-type kinetics of replication and reactivation and that are genetically stable. We engineered an HSV-2 strain expressing the fluorescent mNeonGreen protein as a fusion with the VP26 capsid protein. This virus has normal replication and in vivo recurrence phenotypes, providing an essential improved tool for further study of HSV-2 infection.

High Burden of HIV, Syphilis and HSV-2 and Factors Associated with HIV Infection Among Female Sex Workers in Tanzania: Implications for Early Treatment of HIV and Pre-exposure Prophylaxis (PrEP)

This paper estimates population-based prevalence of HIV, syphilis, HSV-2 and factors influencing HIV infection using a national sample of 1914 female sex workers (FSWs) in 7 regions in Tanzania. Additionally, HIV incidence was estimated by comparing biological HIV results with self-reported HIV status. The average HIV prevalence among FSWs in all 7 regions was 28%, ranging from 14% in Tabora to 38% in Shinyanga. HIV incidence was found to be 13 per 100 person-years. Syphilis prevalence was 8% with significantly higher burden found in Iringa (11%), Mbeya (13%), and Shinyanga (12%). Nearly 60% of the study population was infected with HSV-2. The high HIV prevalence and incidence coupled with suboptimal condom use indicate an urgent need to roll out the "Treat-All" approach and provide antiretroviral therapy to FSWs living with HIV regardless of their CD4 count. In addition, antiretroviral-based prevention technologies such as oral pre-exposure prophylaxis and microbicides should be piloted and evaluated.