Sexually transmitted herpes simplex viruses

The Peptide A-3302-B Isolated from a Marine Bacterium Micromonospora sp. Inhibits HSV-2 Infection by Preventing the Viral Egress from Host Cells

Herpesviruses are highly prevalent in the human population, and frequent reactivations occur throughout life. Despite antiviral drugs against herpetic infections, the increasing appearance of drug-resistant viral strains and their adverse effects prompt the research of novel antiherpetic drugs for treating lesions. Peptides obtained from natural sources have recently become of particular interest for antiviral therapy applications. In this work, we investigated the antiviral activity of the peptide A-3302-B, isolated from a marine bacterium, Micromonospora sp., strain MAG 9-7, against herpes simplex virus type 1, type 2, and human cytomegalovirus. Results showed that the peptide exerted a specific inhibitory activity against HSV-2 with an EC50 value of 14 μM. Specific antiviral assays were performed to investigate the mechanism of action of A-3302-B. We demonstrated that the peptide did not affect the expression of viral proteins, but it inhibited the late events of the HSV-2 replicative cycle. In detail, it reduced the cell-to-cell virus spread and the transmission of the extracellular free virus by preventing the egress of HSV-2 progeny from the infected cells. The dual antiviral and previously reported anti-inflammatory activities of A-3302-B, and its effect against an acyclovir-resistant HSV-2 strain are attractive features for developing a therapeutic to reduce the transmission of HSV-2 infections.

An Interleukin 12 Adjuvanted Herpes Simplex Virus 2 DNA Vaccine Is More Protective Than a Glycoprotein D Subunit Vaccine in a High-Dose Murine Challenge Model

Vaccination is a proven intervention against human viral diseases; however, success against Herpes Simplex Virus 2 (HSV-2) remains elusive. Most HSV-2 vaccines tested in humans to date contained just one or two immunogens, such as the virion attachment receptor glycoprotein D (gD) and/or the envelope fusion protein, glycoprotein B (gB). At least three factors may have contributed to the failures of subunit-based HSV-2 vaccines. First, immune responses directed against one or two viral antigens may lack sufficient antigenic breadth for efficacy. Second, the antibody responses elicited by these vaccines may have lacked necessary Fc-mediated effector functions. Third, these subunit vaccines may not have generated necessary protective cellular immune responses. We hypothesized that a polyvalent combination of HSV-2 antigens expressed from a DNA vaccine with an adjuvant that polarizes immune responses toward a T helper 1 (Th1) phenotype would compose a more effective vaccine. We demonstrate that delivery of DNA expressing full-length HSV-2 glycoprotein immunogens by electroporation with the adjuvant interleukin 12 (IL-12) generates substantially greater protection against a high-dose HSV-2 vaginal challenge than a recombinant gD subunit vaccine adjuvanted with alum and monophosphoryl lipid A (MPL). Our results further show that DNA vaccines targeting optimal combinations of surface glycoproteins provide better protection than gD alone and provide similar survival benefits and disease symptom reductions compared with a potent live attenuated HSV-2 0ΔNLS vaccine, but that mice vaccinated with HSV-2 0ΔNLS clear the virus much faster. Together, our data indicate that adjuvanted multivalent DNA vaccines hold promise for an effective HSV-2 vaccine, but that further improvements may be required.

Effects of thyroid hormone on HSV-1 gene regulation: implications in the control of viral latency and reactivation

Thyroid hormone (TH) is involved in many biological functions such as animal development, cell differentiation, etc. Variation and/or disruption of plasma TH level often led to abnormalities and physiological disorders. TH exerts the effects through its nuclear receptors (TR). Literature showed that procedures resulted in TH alteration also linked to reactivation of several viruses including Herpes Simplex Virus Type -1 (HSV-1). Bioinformatic analyses revealed a number of putative TH responsive elements (TRE) located in the critical regulatory regions of HSV-1 genes such as thymidine kinase (TK), latency associated transcript (LAT), etc. Studies using neuronal cell lines have provided evidences demonstrating that liganded TR regulated viral gene expression via chromatin modification and controlled viral replication. The removal of TH reversed the inhibition and induced the viral replication previously blocked by TH. These results suggest that TH may have implication to participate in the control of reactivation during HSV-1 latency.

A live-attenuated HSV-2 ICP0 virus elicits 10 to 100 times greater protection against genital herpes than a glycoprotein D subunit vaccine

Glycoprotein D (gD-2) is the entry receptor of herpes simplex virus 2 (HSV-2), and is the immunogen in the pharmaceutical industry's lead HSV-2 vaccine candidate. Efforts to prevent genital herpes using gD-2 subunit vaccines have been ongoing for 20 years at a cost in excess of $100 million. To date, gD-2 vaccines have yielded equivocal protection in clinical trials. Therefore, using a small animal model, we sought to determine if a live-attenuated HSV-2 ICP0⁻ virus would elicit better protection against genital herpes than a gD-2 subunit vaccine. Mice immunized with gD-2 and a potent adjuvant (alum+monophosphoryl lipid A) produced high titers of gD-2 antibody. While gD-2-immunized mice possessed significant resistance to HSV-2, only 3 of 45 gD-2-immunized mice survived an overwhelming challenge of the vagina or eyes with wild-type HSV-2 (MS strain). In contrast, 114 of 115 mice immunized with a live HSV-2 ICP0⁻ virus, 0ΔNLS, survived the same HSV-2 MS challenges. Likewise, 0ΔNLS-immunized mice shed an average 125-fold less HSV-2 MS challenge virus per vagina relative to gD-2-immunized mice. In vivo imaging demonstrated that a luciferase-expressing HSV-2 challenge virus failed to establish a detectable infection in 0ΔNLS-immunized mice, whereas the same virus readily infected naïve and gD-2-immunized mice. Collectively, these results suggest that a HSV-2 vaccine might be more likely to prevent genital herpes if it contained a live-attenuated HSV-2 virus rather than a single HSV-2 protein.

Herpes simplex virus 2 ICP0 mutant viruses are avirulent and immunogenic: implications for a genital herpes vaccine

Herpes simplex virus 1 (HSV-1) ICP0⁻ mutants are interferon-sensitive, avirulent, and elicit protective immunity against HSV-1 (Virol J, 2006, 3:44). If an ICP0⁻ mutant of herpes simplex virus 2 (HSV-2) exhibited similar properties, such a virus might be used to vaccinate against genital herpes. The current study was initiated to explore this possibility. Several HSV-2 ICP0⁻ mutant viruses were constructed and evaluated in terms of three parameters: i. interferon-sensitivity; ii. virulence in mice; and iii. capacity to elicit protective immunity against HSV-2. One ICP0⁻ mutant virus in particular, HSV-2 0ΔNLS, achieved an optimal balance between avirulence and immunogenicity. HSV-2 0ΔNLS was interferon-sensitive in cultured cells. HSV-2 0ΔNLS replicated to low levels in the eyes of inoculated mice, but was rapidly repressed by an innate, Stat 1-dependent host immune response. HSV-2 0ΔNLS failed to spread from sites of inoculation, and hence produced only inapparent infections. Mice inoculated with HSV-2 0ΔNLS consistently mounted an HSV-specific IgG antibody response, and were consistently protected against lethal challenge with wild-type HSV-2. Based on their avirulence and immunogenicity, we propose that HSV-2 ICP0⁻ mutant viruses merit consideration for their potential to prevent the spread of HSV-2 and genital herpes.

HSV: what you need to know to care for your pregnant patient

The purpose of this article is to provide nurses with information about herpes simplex virus (HSV): its transmission and diagnosis, and the recommended management during pregnancy and birth. Genital herpes is one of the three most common, chronic sexually transmitted infections in the United States. Diagnosis of HSV infection is challenging, because obtaining cultures of lesions can be difficult and delays occur before accurate results are available. Serological testing can determine whether a person has had the infection, but antibodies are not present in sufficient quantities for about 6 to 12 weeks after exposure, leaving a large window of time for false-negative results. Pregnant women who have genital herpes present a complex management situation because fetal exposure to the virus during the birth process can lead to neonatal infection and high morbidity and mortality rates. Appropriate physical, psychological, and educational management of seropositive and/or symptomatic women during pregnancy, coupled with prompt diagnosis and treatment of infected newborns, offers the best hope for positive outcomes.

Phase I dose-escalation study of a monovalent heat shock protein 70-herpes simplex virus type 2 (HSV-2) peptide-based vaccine designed to prime or boost CD8 T-cell responses in HSV-naïve and HSV-2-infected subjects

This was a phase I study to assess the safety, tolerability, and immunogenicity of escalating doses of AG-702, a noncovalent complex of an HLA A*0201-restricted epitope in the glycoprotein B protein of herpes simplex virus type 2 (gB2) and truncated human constitutive heat shock protein 70. Similar vaccines have been immunogenic in animals. Three injections of 10 to 250 mug were administered intradermally to HLA A*0201-bearing subjects who were either herpes simplex virus type 2 (HSV-2)-infected or HSV uninfected. Sixty-two participants received the vaccine, 60 completed the protocol, and T-cell data were accrued for 56 subjects. The vaccine was safe and well tolerated. New or boosted responses to the HSV-2 CD8 epitope were not detected. Baseline responses to an epitope in virion proteins 13/14 were higher than responses to the gB2 epitope. A heat shock protein vaccine with an HSV-2 peptide appears to be safe at the doses studied in healthy adults with or without HSV infection. Modifications of the dose, adjuvant, route, schedule, or HSV antigen may be required to improve responses.

Susceptibility of human female primary genital epithelial cells to herpes simplex virus, type-2 and the effect of TLR3 ligand and sex hormones on infection

Genital epithelial cells (ECs) are the first line of defense that sexually transmitted viruses encounter. The mechanism of viral pathogenesis in these cells is not well understood. Here, we show that a primary cell culture model from human reproductive tract tissues can be used as a novel ex vivo model in examining the interaction of herpes simplex virus, type 2 (HSV-2), with female genital mucosa. Confluent, polarized primary cultures of human endometrial and cervical ECs were established and shown to be free from any significant contamination of any other cell type. Both endometrial and cervical ECs were found to be highly susceptible to HSV-2 infection. The kinetic of infection was similar to in vivo infection, with the earliest viral shedding seen at 18 h postinfection. Primary EC monolayers could be infected both apically and basolaterally, but preferential viral shedding was seen on the apical side of cells. Following treatment of the monolayers with poly (I:C), an innate immune activator that acts via TLR3, viral shedding was reduced significantly, comparable to levels seen when an antiviral formulation, acyclovir, was used. Treatment of epithelial and stromal co-cultures with estradiol increased HSV-2 infection in endometrial ECs, but viral shedding decreased following treatment with progesterone. To the best of our knowledge, this is the first study that examines the interaction of primary human female genital ECs with HSV-2, using an ex vivo culture model. The results provide valuable information regarding the susceptibility of women's genital ECs to HSV-2 and the ability of innate immunity and hormones to modify this susceptibility.

Prevalence of antibodies against herpes simplex virus types 1 and 2 in children and young people in an urban region in Tanzania

Herpes simplex virus type 1 (HSV-1) is transmitted by close contact, both sexual and nonsexual, and infections are acquired during childhood and adolescence. Herpes simplex virus type 2 (HSV-2), however, is thought to be transmitted mainly by sexual contact. Most HSV-2 infections are consequently expected to occur after the onset of sexual activity. Recent reports indicate an increasing prevalence of HSV-2 on the African continent, but most studies have been performed on adult cohorts. In the present study, we collected sera from Tanzanian children and young persons from 1 to 20 years old, with at least 100 individuals in each age group. Antibodies against HSV-1 and HSV-2 were detected by an in-house Western blot method which was shown to perform well in comparison with a commercial Western blot assay. Type-specific antibodies were also analyzed by two noncommercial enzyme-linked immunosorbent assay methods based upon the antigenicities of branched synthetic oligopeptides corresponding to epitopes in glycoprotein G of HSV-1 or HSV-2. The prevalence of HSV-1 antibodies increased gradually from 73% for the age group of 1 to 4 years to 92% for the age group of 17 to 20 years. The prevalence of HSV-2 antibodies was unexpectedly high, as 15% of the children were infected by the age of 8 years, with the incidence increasing gradually to 40% in the age group of 17 to 20 years. The reason for this unexpectedly high frequency is not clear but could suggest that nonsexual transmission of HSV-2 is more common than previously thought. There was no statistically significant association between seropositivities for HSV-2 and human immunodeficiency virus.

Minimal change in HSV-2 seroreactivity: a cross-sectional Swedish population study

The prevalence of antibodies to herpes simplex virus type 2 (HSV-2) was determined in sera collected from 2 Swedish cross-sectional populations during 1990/91 and 1996/97. A glycoprotein G2 (gG-2) peptide ELISA was used to analyse 2899 sera from adults. We found a prevalence of 13.0% in 18-70-y-olds in 1990/91 and 16.4% in 31-55-y-olds in 1996/97. Seropositivity to HSV-2 was somewhat higher in women than in men; 14.4% compared to 11.6% in 1990/91 and 18.9% compared to 13.6% in 1996/97. Overall there was a significant difference in female prevalence of HSV-2 compared to prevalence in males of the same age groups (p=0.013). Total antibody prevalence to HSV-1 of 88% in HSV-2 negative individuals above 18 y of age was found. HSV-2 positive individuals were found seropositive to HSV-1 in approximately 95% of the cases. 12% were negative for both HSV-1 and HSV-2 antibodies. In addition, there was no serological sign that the reported increase of HSV-1 as an early sexual disease had reduced the frequency of HSV-2 seropositivity in the sexually most active age groups. In conclusion, our investigation has shown no significant increase of HSV-2 seroprevalence in randomly selected Swedish subjects during the defined time period.

Epidemiology of genital herpes simplex virus infections in a community-based sample in France: results of the HERPIMAX study

OBJECTIVE

The objective of this study was to provide information on the prevalence of herpes simplex infections in the general population in Europe.

GOALS

The goals of this study were to determine the prevalence of clinically probable genital herpes and the relationship between serotype and clinical expression in a French community-based sample.

STUDY

A total of 4410 subjects chosen at random were serotyped for herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2). Data on symptoms were obtained by questionnaire allowing retrospective diagnosis of clinically probable genital herpes.

RESULTS

Questionnaire data and serotype were available for 3192 subjects. Seroprevalences of HSV-1 and HSV-2 were 65.6% and 15.5%, respectively. Prevalence of clinically probable genital herpes was 11.8%, identified in 11.1% of HSV-1-positive subjects and 26.8% of HSV-2-positive subjects, with a lower prevalence in those coinfected with both virus types.

CONCLUSIONS

Clinically probable genital herpes was observed in one fourth of subjects with HSV-2 infections and in some subjects with HSV-1 infection. Coinfection with HSV-1 appeared to protect against symptom expression in subjects infected with HSV-2.

Prevention of genital herpes in a guinea pig model using a glycoprotein D-specific single chain antibody as a microbicide

Background

Genital herpes (GH) is a recurrent sexually transmitted infection (STI) that causes significant morbidity and is also the major source of herpes simplex virus (HSV) in cases of neonatal herpes. Vaccination is a current goal which has had limited success so far in preventing GH and microbicides offer an attractive alternative. Treatment of primary disease cannot prevent establishment of latent infections and thus, cannot prevent subsequent recurrent disease. Recently, many of the molecular events leading to entry of HSV into cells have been elucidated, resulting in the description of a number of herpesvirus entry mediators (HVEMs) that interact with HSV glycoprotein D (gD) on the surface of virions. Described here is a strategy for interrupting the spread of HSV based on interfering with these interactions. The hypothesis addressed in the current report was that single chain antibody variable fragments (scFv) that interrupt associations between gD and HVEMs would not only prevent infection in vitro but could also be used as microbicides to interfere with acquisition GH.

Results and Conclusions

Here we show that a scFv derived from a particular hybridoma, DL11, not only inhibits infection in vitro but also prevents development of GH in a guinea pig model when applied intravaginally in an inert vehicle. Comparison of different anti-gD single chain antibodies supported the hypothesis that the activity of DL11-scFv is based on its ability to disrupt the associations between gD and the two major receptors for HSV, nectin-1 and HveA. Further, the results predict that bacterial expression of active single chain antibodies can be optimized to manufacture inexpensively a useful microbicidal product active against HSV.

Management of neonatal herpes simplex virus infections

As many as 2,500 infants develop neonatal herpes each year, most of whom are born to women with no history or physical findings suggestive of genital herpes. Infection usually takes one of three forms: 1) disease localized to skin, eyes, and mucous membranes, 2) localized central nervous system infection, or 3) disseminated infection. Exposure to the virus occurs during passage through an infected birth canal, but 5% of infants acquire the infection in utero. The mortality rate is 31% for disseminated infection and 6% for localized central nervous system disease; long-term neurologic sequelae are seen in 17% and 70% of survivors, respectively. Diagnosis is made by isolating of the virus from skin lesions or other involved sites. The polymerase chain reaction for the detection of viral DNA in cerebrospinal fluid or serum is now the diagnostic test of choice for central nervous system or disseminated neonatal herpes because it has higher sensitivity than traditional culture methods. Treatment is with high-dose intravenous acyclovir (60 mg/kg per day in three divided doses), with adjustments made for infants with renal or hepatic insufficiency. Supportive measures and neuroimaging studies are often required. Acyclovir is administered for three weeks, but infants with disease localized to the skin, eyes, and mucous membranes can be treated for two weeks if the cerebrospinal fluid polymerase chain reaction assay is negative for herpes simplex virus DNA. Prevention of infection in infants can be accomplished by cesarean delivery when women have active lesions at the onset of labor. Neonates delivered through an infected birth canal should be screened between 24 and 48 hours of age with viral cultures of eyes, nasopharynx, mouth, and rectum. If positive, they should be treated with acyclovir even if asymptomatic. Suppressive acyclovir therapy beginning at 36 weeks gestation is often prescribed for women with frequent recurrences of genital herpes.