Biologic interactions between HSV-2 and HIV-1 and possible implications for HSV vaccine development

Development of a safe and effective vaccine against herpes simplex virus type 2 (HSV-2) has the potential to limit the global burden of HSV-2 infection and disease, including genital ulcer disease and neonatal herpes, and is a global sexual and reproductive health priority. Another important potential benefit of an HSV-2 vaccine would be to decrease HIV infections, as HSV-2 increases the risk of HIV-1 acquisition several-fold. Acute and chronic HSV-2 infection creates ulcerations and draws dendritic cells and activated CD4+ T cells into genital mucosa. These cells are targets for HIV entry and replication. Prophylactic HSV-2 vaccines (to prevent infection) and therapeutic vaccines (to modify or treat existing infections) are currently under development. By preventing or modifying infection, an effective HSV-2 vaccine could limit HSV-associated genital mucosal inflammation and thus HIV risk. However, a vaccine might have competing effects on HIV risk depending on its mechanism of action and cell populations generated in the genital mucosa. In this article, we review biologic interactions between HSV-2 and HIV-1, consider HSV-2 vaccine development in the context of HIV risk, and discuss implications and research needs for future HSV vaccine development.     

Incidence of herpes neonatorum in Netherlands

OBJECTIVE: Investigation of the incidence of neonatal herpes in the Netherlands between 1992 and 1998. DESIGN: Inventory questionnaire survey. METHODS: All virological laboratories in the Netherlands were sent a questionnaire on the number of culture proven cases of neonatal herpes recorded between 1992 and 1998 and on the type of herpes simplex virus (HSV-1 or HSV-2). The gynaecological and paediatric departments of all university hospitals and of half of the general hospitals were sent questionnaires as well. Gynaecologists were asked how often caesarean section was performed in order to prevent neonatal herpes and how frequently pregnant women were seen with genital herpes. Paediatricians were asked how often they observed neonatal herpes, the type of HSV and the possible transmission route. Based on these data the figures for the whole of the Netherlands were estimated. RESULTS: The incidence of neonatal herpes in the Netherlands in the period 1992 to 1998 was 2.4 per 100,000 neonates. HSV-1 was the cause of neonatal herpes in 73%, HSV-2 in 9%, and in 18% of the cases the type of infection was not recorded. The number of pregnant women with genital herpes had increased, but, in agreement with a consensus statement, the gynaecologists hardly performed caesarean sections any more to prevent neonatal herpes (2 per year). CONCLUSIONS: The incidence of neonatal herpes in the Netherlands had not increased. There was no predominant role of HSV type 2 causing neonatal herpes.     

Prevalence of antibodies to herpes simplex virus types 1 and 2 in pregnant women, and estimated rates of infection.

There has been a recent increase in notifications of genital herpes but it is not known whether this has been reflected in the pregnant population. We have therefore carried out a study to determine the prevalence of herpes simplex antibodies in pregnant women and to estimate the incidence of primary infection. Sera were collected from 3533 women at antenatal clinics and tested for total antibodies to herpes simples virus (HSV), and if positive, for specific antibodies to HSV-2. Estimates of HSV-1 seroprevalence were derived from the HSV-2 seronegative population. HSV-1 seroprevalence was nearly 100% in black women born in Africa or the Caribbean and 60-80% in white, Asian and UK born black women. It was lower in women in non-manual employment. HSV-2 seroprevalence was related to age, rising from 0 at age 16 to 40% at age 35 in black women, and to about 10% in Asian and white women. The estimated incidence of primary HSV-2 infection during pregnancy, per 1000 pregnancies, was about 2.4 in Asian women, 5 in white women, and 20 in black women. Estimates of the incidence of neonatal infection were derived from these figures and compared to the nationally reported rates.     

A randomized controlled trial of a replication defective (gH deletion) herpes simplex virus vaccine for the treatment of recurrent genital herpes among immunocompetent subjects

BACKGROUND: A replication incompetent herpes virus lacking the glycoprotein H gene has been developed as a potential therapeutic vaccine for genital herpes. GOAL: To determine vaccine efficacy on reducing HSV reactivation and clinical disease among immunocompetent persons with recurrent genital HSV-2 infection. STUDY DESIGN: Randomized multicenter placebo-controlled trial. Healthy volunteers who had six or more recurrences of genital herpes per year were randomized to receive injections of vaccine at 0 and 8 or 0, 4, and 8 or 0, 2, 4, and 8 weeks or placebo and were followed for subsequent recurrences for 1 year. RESULTS: The median times to first recurrence of genital herpes (40 days versus 30 days versus 37 days versus 42 days, respectively), mean number of recurrences (3 versus 3 versus 2.4 versus 1.9, respectively), and time to lesion healing of the first recurrence (8 days versus 7.8 days versus 7.4 days versus 7.5 days, respectively), were similar for all treatment groups. Asymptomatic viral shedding was detected by PCR in 61/74 (82%) persons performing daily sample collection following completion of the vaccination series. No differences were noted in the proportion of days with shedding between treatment groups (11.9% versus 17.2% versus 13.1% versus 16.4%, respectively). CONCLUSION: This replication incompetent HSV-2 vaccine lacking the glycoprotein H gene was safe but had no clinical or virologic benefit in the amelioration of genital HSV-2 disease among immunocompetent men and women.     

Evaluation of AD472, a live attenuated recombinant herpes simplex virus type 2 vaccine in guinea pigs

An attenuated recombinant herpes simplex virus type 2 (HSV-2), designated as AD472, was constructed by deleting both copies of the gamma(1)34.5 gene, UL55-56, UL43.5, and the US10-12 region from HSV-2 strain G. This virus was engineered to be a safe and effective live attenuated HSV-2 vaccine and was tested in the guinea pig model of genital herpes to evaluate its ability to protect from disease upon challenge with the wild type (wt) virus, HSV-2 (G). AD472 administered intramuscularly did not prevent infection or virus replication in the vaginal tract, but did reduce both lesion development and severity in a dose-dependent manner in guinea pigs challenged with the wt virus. Frequency of reactivation from latency was low compared with that of the parent virus, HSV-2 (G). Immunization with AD472 at doses of 1x10(5)PFU generally precluded colonization of the ganglia or establishment of latency by the challenge virus. Results presented here support the concept of a rationally engineered live attenuated vaccine for the prevention of the genital disease associated with infection by HSV-2.     

The adjuvant CLDC increases protection of a herpes simplex type 2 glycoprotein D vaccine in guinea pigs

Herpes simplex virus (HSV) infections are common but there is no vaccine available. We evaluated cationic liposome–DNA complexes (CLDC) as an adjuvant for an HSV gD2 vaccine and compared it to an MPL/Alum adjuvant in a guinea pig model of genital herpes. The addition of CLDC to the gD2 vaccine significantly decreased acute and recurrent disease and most importantly the number of days with recurrent virus shedding compared to gD2 alone. Reductions in these outcomes were also detected when gD2 + CLDC was compared to gD2 + MPL/Alum. When the vaccine and adjuvants were evaluated as therapeutic vaccines, they were ineffective. CLDC enhanced protection compared to MPL/Alum and is the first vaccine to reduce recurrent virus shedding, a key to decreasing the spread of HSV-2.     

青岛地区不同职业人群中生殖器单纯疱疹病毒感染情况的流行病学调查

在青岛地区对随机抽查的１１个不同职业及两个特殊人群（妊娠、宫颈癌）中１１４８份生殖器分泌物，应用单克隆抗体双夹心法酶联免疫吸附试验（ＭｃＡｂ－ＥＬＩＳＡ），分型检测标本中单纯疱疹病毒（ＨＳＶ）抗原，总阳性一率为２２．６％，其中ＨＳＶ－１占２０．０％。在不同性别中，男性标本中ＨＳＶ抗原阳性率２４．２％，女性为２１．５％，两者无显著性差异。特殊职业，反途贩运司标本中，ＨＳＶ抗原阳性率为４８．０％，个体     

Genital herpes vaccines--cause for cautious optimism

The high prevalence of herpes simplex virus infections in many communities, its numerous serious physical and psychological complications and its importance in enhancing the transmission of HIV make this virus an obvious target for prevention by vaccination. Randomised clinical trials of only one genital herpes vaccine has shown efficacy so far. Analysis of clinical results is complicated by the difference between disease and infection, different results for males and females and the interaction between HSV-1 and HSV-2 immunity.     

Neonatal herpes simplex virus infection in the British Isles

Summary. This study was set up to estimate the incidence of neonatal herpes simplex virus (HSV) infection in the British Isles, and to document the outcome of neonatal infection. Paediatricians reported cases of neonatal HSV through the active reporting scheme of the British Paediatric Association Surveillance Unit. Over a 5half year period (1986-91) 76 infants with neonatal HSV infection were reported, an incidence of recognised infection in the British Isles of 1.65/100000 livebirths. Twenty-five infants had HSV-1 infection, 24 HSV-2 and in 27 virus type was unknown. Twenty-seven had disseminated infection, 23 herpes encephalitis and 26 localised infection. Nineteen infants (25%) died in the neonatal period, and a further 25 (33%) have subsequently died or have long-term sequelae. At least half of the infants had been discharged home before symptoms became apparent. For 21 women there was evidence of a maternal genital herpes infection at some time, but this was reported or diagnosed retrospectively after neonatal HSV was suspected in 19 cases, and ante-natally in only two. Neonatal HSV is rare in the British Isles and routine antenatal screening for genital herpes infection during pregnancy is not justified. A high proportion of infected infants present with non-specific signs and symptoms and without mucocutaneous involvement; furthermore, there is rarely a history of maternal infection. As early diagnosis and prompt treatment is essential, there must be a high level of awareness of the serious nature of neonatal HSV infection.     

The challenges and opportunities for the development of a T-cell epitope-based herpes simplex vaccine

Herpes simplex virus type 1 and type 2 (HSV-1 & HSV-2) infections have been prevalent since the ancient Greek times. To this day, they still affect a staggering number of over a billion individuals worldwide. HSV-1 infections are predominant than HSV-2 infections and cause potentially blinding ocular herpes, oro-facial herpes and encephalitis. HSV-2 infections cause painful genital herpes, encephalitis, and death in newborns. While prophylactic and therapeutic HSV vaccines remain urgently needed for centuries, their development has been difficult. During the most recent National Institute of Health (NIH) workshop titled “Next Generation Herpes Simplex Virus Vaccines: The Challenges and Opportunities”, basic researchers, funding agencies, and pharmaceutical representatives gathered: (i) to assess the status of herpes vaccine research; and (ii) to identify the gaps and propose alternative approaches in developing a safe and efficient herpes vaccine. One “common denominator” among previously failed clinical herpes vaccine trials is that they either used a whole virus or a whole viral protein, which contain both “pathogenic symptomatic” and “protective asymptomatic” antigens and epitopes. In this report, we continue to advocate developing “asymptomatic” epitope-based sub-unit vaccine strategies that selectively incorporate “protective asymptomatic” epitopes which: (i) are exclusively recognized by effector memory CD4⁺ and CD8⁺ T cells (T_EM cells) from “naturally” protected seropositive asymptomatic individuals; and (ii) protect human leukocyte antigen (HLA) transgenic animal models of ocular and genital herpes. We review the role of animal models in herpes vaccine development and discuss their current status, challenges, and prospects.     

Immunotherapeutic activity of a recombinant combined gB-gD-gE vaccine against recurrent HSV-2 infections in a guinea pig model

The guinea pig model of recurrent genital herpes simplex virus type 2 (HSV-2) infection was used to test the immunotherapeutic activity of a glycoprotein subunit vaccine. Vaccine formulation consisted of three recombinant herpes simplex virus (HSV) glycoproteins, namely gB1s, gD2t and gE1t, plus aluminium hydroxide [Al(OH)3)] adjuvant. One month after viral challenge, infected animals were therapeutically immunised by seven subcutaneous injections of a low dose of antigens with a weekly interval for the first five and a fortnightly interval for the last two administrations. Results showed that the treatment was highly effective in ameliorating the recidivist pathology of animals, suggesting that this kind of vaccine formulation and administration may be helpful for therapeutic intervention in humans affected by recurrent herpes infections.     

Status of vaccine research and development of vaccines for herpes simplex virus

Herpes simplex virus type-1 (HSV-1) and -2 (HSV-2) are highly prevalent global pathogens which commonly cause recurrent oral and genital ulcerations. Less common but more serious complications include meningitis, encephalitis, neonatal infection, and keratitis. HSV-2 infection is a significant driver of the HIV epidemic, increasing the risk of HIV acquisition 3 fold. As current control strategies for genital HSV-2 infection, including antiviral therapy and condom use, are only partially effective, vaccines will be required to reduce infection. Both preventive and therapeutic vaccines for HSV-2 are being pursued and are in various stages of development. We will provide an overview of efforts to develop HSV-2 vaccines, including a discussion of the clinical need for an HSV vaccine, and status of research and development with an emphasis on recent insights from trials of vaccine candidates in clinical testing. In addition, we will touch upon aspects of HSV vaccine development relevant to low and middle income countries.     

Reduction of recurrent HSV disease using imiquimod alone or combined with a glycoprotein vaccine

The aim of this study is to evaluate the effects of an immune modulator, imiquimod, given alone or in combination with an HSV vaccine on HSV immune responses and as immunotherapy of a genital recurrence model. After recovery from primary genital HSV infection, animals were randomized to placebo, 21 days of imiquimod plus a placebo vaccine, or 21 days of imiquimod plus an HSV-2 glycoprotein vaccine. Placebo or HSV vaccine was given in the footpad on days 16 and 37 after HSV-2 genital inoculation. Daily imiquimod or placebo was given subcutaneously in the shoulder on days 16 through 37. Genital recurrences were monitored and HSV specific NK activity, IL-2 response and ELISA antibody were assayed. For the entire 15 week observation period, imiquimod alone reduced recurrences 62.6%, while addition of HSV vaccine to imiquimod reduced recurrences 80.6% compared to placebo/placebo. The duration of significant recurrence reduction was more notable with the addition of vaccine. Imiquimod alone significantly reduced the weekly HSV recurrent disease in the first 10 weeks (53-94% reduction, mean 75.9%), as did imiquimod plus HSV-vaccine (71-98% reduction, mean 89.5%). In weeks 10-15, imiquimod alone reduced recurrences significantly only in week 10 (20-53% reduction, mean 33%), whereas the addition of vaccine extended the significant recurrence reduction to 14 weeks (44-71% reduction, mean 56.8%). The recurrence reduction is correlated to an increased HSV-induced in vitro IL-2 response and NK activity against HSV targets in treated groups. Both imiquimod and the imiquimod/vaccine combination significantly reduced genital HSV recurrences, but the combination extended the duration and extent of protection for recurrences compared to imiquimod alone. Enhanced HSV specific immune responses correlated to the protection.     

Neonatal herpes simplex virus infection following Jewish ritual circumcisions that included direct orogenital suction - New York City, 2000-2011

Herpes simplex virus (HSV) infection commonly causes "cold sores" (HSV type 1 [HSV-1]) and genital herpes (HSV-1 or HSV type 2 [HSV-2]); HSV infection in newborns can result in death or permanent disability. During November 2000-December 2011, a total of 11 newborn males had laboratory-confirmed HSV infection in the weeks following out-of-hospital Jewish ritual circumcision, investigators from the New York City Department of Health and Mental Hygiene (DOHMH) learned. Ten of the 11 newborns were hospitalized; two died. In six of the 11 cases, health-care providers confirmed parental reports that the ritual circumcision included an ultra-Orthodox Jewish practice known as metzitzah b'peh, in which the circumciser (mohel, plural: mohelim) places his mouth directly on the newly circumcised penis and sucks blood away from the circumcision wound (direct orogenital suction). In the remaining cases, other evidence suggested that genital infection was introduced by direct orogenital suction (probable direct orogenital suction). Based on cases reported to DOHMH during April 2006-December 2011, the risk for neonatal herpes caused by HSV-1 and untyped HSV following Jewish ritual circumcision with confirmed or probable direct orogenital suction in New York City was estimated at 1 in 4,098 or 3.4 times greater than the risk among male infants considered unlikely to have had direct orogenital suction. Oral contact with a newborn's open wound risks transmission of HSV and other pathogens. Circumcision is a surgical procedure that should be performed under sterile conditions. Health-care professionals advising parents and parents choosing Jewish ritual circumcision should inquire in advance whether direct orogenital suction will be performed, and orogenital suction should be avoided.     

The HSV-1 live attenuated VC2 vaccine provides protection against HSV-2 genital infection in the guinea pig model of genital herpes

Background

Although development of an HSV vaccine is a priority there is currently no vaccine available. The recent failure of subunit vaccines suggest that presentation of more antigens via a live attenuated vaccine may be required for protection. We therefore evaluated VC2, a live attenuated HSV vaccine, engineered to be unable to enter into neuronal axons.

Effects of herpes simplex virus type 2 glycoprotein vaccines and CLDC adjuvant on genital herpes infection in the guinea pig

Genital herpes simplex virus (HSV) infections are common but results from vaccine trials with HSV-2 glycoprotein D (gD) have been disappointing. We therefore compared a similar HSV gD2 vaccine, to a further truncated gD2 vaccine, to a vaccine with gD2 plus gB2 and gH2/gL2 and to a vaccine with only gB2 and gH2/gL2 in a guinea pig model of genital herpes. All vaccines were administered with cationic liposome-DNA complexes (CLDC) as an adjuvant. All vaccines significantly decreased the severity of acute genital disease and vaginal virus replication compared to the placebo group. The majority of animals in all groups developed at least one episode of recurrent disease but the frequency of recurrent disease was significantly reduced by each vaccine compared to placebo. No vaccine was significantly more protective than gD2 alone for any of the parameters described above. No vaccine decreased recurrent virus shedding. When protection against acute infection of dorsal root ganglia and the spinal cord was evaluated all vaccines decreased the per cent of animal with detectable virus and the quantity of virus but again no vaccine was significantly more protective than another. Improvements in HSV-2 vaccines may require inclusion of more T cell targets, more potent adjuvants or live virus vaccines.     

A vaccine containing highly purified virus particles in adjuvant provides high level protection against genital infection and disease in guinea pigs challenged intravaginally with homologous and heterologous strains of herpes simplex virus type 2

Infection with Herpes Simplex Viruses (HSVs) represents a significant health burden worldwide with HSV-1 and HSV-2 causing genital disease and HSV-2 contributing to human immunodeficiency virus acquisition. Despite great need, there is currently no licensed vaccine against HSV. In this report, we evaluated the protective efficacy of a vaccine containing highly purified, inactivated HSV-2 particles (with and without additional recombinant glycoprotein D) formulated with a monophosphoryl lipid A/Alhydrogel adjuvant in a guinea pig HSV genital model. The key results from 3 independent studies were: (1) vaccination consistently provided significant 3–3.5 Log10 reductions in vaginal HSV-2 titers on day 2 postchallenge; (2) following homologous or heterologous challenge with two U.S. isolates, all vaccine groups showed complete protection against lesion formation, significant 3 Log10 reductions in day 2 virus shedding, enhanced virus clearance, significant reductions in HSV-2 DNA within ganglia, and no detectable shedding (<2 PFU) or latent viral DNA in some immunized animals; (3) following challenge with a third heterologous strain, vaccination provided complete protection against primary and recurrent lesions, significant reductions in primary virus shedding, a 50% reduction in recurrent shedding days, and undetectable latent virus in the ganglia and spinal cords of most animals; and (4) adding glycoprotein D provided no enhanced protection relative to that elicited by the inactivated HSV-2 particles alone. Together, these data provide strong support for further development of this exceedingly protective and highly feasible vaccine candidate for human trials.     

Effect of immunization with herpes simplex virus type-1 (HSV-1) glycoprotein D (gD) plus the immune enhancer GPI-0100 on infection with HSV-1 or HSV-2

These studies were performed to determine the effects of GPI-0100, a semi synthetic Quillaja Saponin analog, formulated with herpes simplex virus type-1 (HSV-1) glycoprotein D (gD) on immunity to HSV. SKH-1 hairless mice, used as a model of herpes labialis, inoculated with HSV-1 results in facial lesions, virus replication and mortality. Mortality rates, lesion scores and viral titers were significantly reduced in SKH-1 mice immunized with gD/GPI-0100 prior to cutaneous inoculation with HSV-1 and the protective effects were greater than those using the standard alum adjuvant. Genital HSV-2 infections in guinea pigs were also utilized to determine if gD combined with GPI-0100 was protective against infection, disease severity and viral shedding. Guinea pigs immunized with HSV-1 gD with or without GPI-0100 had significantly reduced area under the curve lesion scores, but infection rates and virus shedding was not altered. When Tween 40 was added to gD and GPI-0100, mean peak lesion scores were also significantly reduced. The results obtained in a genital HSV-2 infection of guinea pigs did not indicate enhanced protection or reduced virus shedding following immunization with GPI-0100 and gD. There was, however, a significant improvement in clinical herpetic genital disease with the combination of gD plus the immune enhancer GPI-0100.     

Construction and properties of a herpes simplex virus 2 dl5-29 vaccine candidate strain encoding an HSV-1 virion host shutoff protein

The replication-defective herpes simplex virus 2 (HSV-2) dl5-29 mutant virus strain with deletions in the U_L5 and U_L29 genes has been shown to protect mice and guinea pigs against challenge with wild-type (wt) HSV-2 and to protect against ocular disease caused by HSV-1 infection. The dl5-29 strain is currently being prepared for clinical trials as a herpes vaccine candidate. As a possible approach to improve the efficacy of dl5-29 as a genital herpes vaccine, we replaced the U_L41 gene encoding the virion host shutoff function (vhs) with the U_L41 gene from HSV-1. While the HSV-2 U_L41 and HSV-1 U_L41 gene products have analogous functions, vhs-1 is 40-fold less active than vhs-2. Previously, it was shown that disruption of the U_L41 gene can increase the efficacy of dl5-29 as a vaccine against HSV-2. These properties led us to hypothesize that replacement of vhs-2 by vhs-1 would decrease cytopathic effects in infected host cells, allowing longer survival of antigen-presenting cells and induction of stronger immune responses. The new recombinant dl5-29-41.1 virus shows nearly the same immunogenicity and protection against HSV-2 challenge as the parental dl5-29 virus or a triply deleted mutant virus, dl5-29-41, in the murine model of infection, and grows to higher titers than the parental strain in complementing cells, which is important for GMP production. The results have implications for the design of future HSV-2 vaccine candidates and mechanisms of induction of protective immunity against genital herpes.     

Protection against herpes simplex virus type 2 infection in a neonatal murine model using a trivalent nucleoside-modified mRNA in lipid nanoparticle vaccine

Neonatal herpes is a dreaded complication of genital herpes infection in pregnancy. We recently compared two vaccine platforms for preventing genital herpes in female mice and guinea pigs and determined that HSV-2 glycoproteins C, D and E expressed using nucleoside-modified mRNA in lipid nanoparticles provided better protection than the same antigens produced as baculovirus proteins and administered with CpG and alum. Here we evaluated mRNA and protein immunization for protection against neonatal herpes. Female mice were immunized prior to mating and newborns were infected intranasally with HSV-2. IgG binding and neutralizing antibody levels in mothers and newborns were comparable using the mRNA or protein vaccines. Both vaccines protected first and second litter newborns against disseminated infection based on virus titers in multiple organs. We conclude that both vaccines are efficacious at preventing neonatal herpes, which leaves the mRNA vaccine as our preferred candidate based on better protection against genital herpes.