Patterns of herpes simplex virus shedding over 1 month and the impact of acyclovir and HIV in HSV-2-seropositive women in Tanzania

Vaccination Route as a Determinant of Protective Antibody Responses against Herpes Simplex Virus

Herpes simplex viruses (HSV) are significant global health problems associated with mucosal and neurologic disease. Prior experimental vaccines primarily elicited neutralizing antibodies targeting glycoprotein D (gD), but those that advanced to clinical efficacy trials have failed. Preclinical studies with an HSV-2 strain deleted in gD (ΔgD-2) administered subcutaneously demonstrated that it elicited a high titer, weakly neutralizing antibodies that activated Fcg receptors to mediate antibody-dependent cellular cytotoxicity (ADCC), and completely protected mice against lethal disease and latency following vaginal or skin challenge with HSV-1 or HSV-2. Vaccine efficacy, however, may be impacted by dose and route of immunization. Thus, the current studies were designed to compare immunogenicity and efficacy following different routes of vaccination with escalating doses of ΔgD-2. We compared ΔgD-2 with two other candidates: recombinant gD protein combined with aluminum hydroxide and monophosphoryl lipid A adjuvants and a replication-defective virus deleted in two proteins involved in viral replication, dl5-29. Compared to the subcutaneous route, intramuscular and/or intradermal immunization resulted in increased total HSV antibody responses for all three vaccines and boosted the ADCC, but not the neutralizing response to ΔgD and dl5-29. The adjuvanted gD protein vaccine provided only partial protection and failed to elicit ADCC independent of route of administration. In contrast, the increased ADCC following intramuscular or intradermal administration of DgD-2 or dl5-29 translated into significantly increased protection. The DgD-2 vaccine provided 100% protection at doses as low as 5 × 104 pfu when administered intramuscularly or intradermally, but not subcutaneously. However, administration of a combination of low dose subcutaneous DgD-2 and adjuvanted gD protein resulted in greater protection than low dose DgD-2 alone indicating that gD neutralizing antibodies may contribute to protection. Taken together, these results demonstrate that ADCC provides a more predictive correlate of protection against HSV challenge in mice and support intramuscular or intradermal routes of vaccination.

Model of vaccine efficacy against HSV-2 superinfection of HSV-1 seropositive mice demonstrates protection by antibodies mediating cellular cytotoxicity

A majority of the world’s population is infected with HSV-1, highlighting the need for vaccines that are effective in HSV-1-seropositive hosts. We established a superinfection model by infecting mice intranasally with a sublethal dose of HSV-1, which results in high rates of seropositive, latently infected mice susceptible to HSV-2 superinfection. Sublethal HSV-1 induced a predominantly neutralizing antibody response. Vaccination of HSV-1-seropositive mice with recombinant adjuvanted glycoprotein D (rgD-2) failed to significantly boost HSV total or neutralizing antibody responses and provided no significant increased protection against HSV-2 superinfection compared to control-vaccinated HSV-1-seropositive mice. In contrast, immunization with a single-cycle virus deleted in gD (ΔgD-2) significantly boosted total HSV-specific antibody titers and elicited new antibody-dependent cell-mediated cytotoxicity responses, providing complete protection from death following HSV-2 superinfection. This model recapitulates clinical responses to natural infection and the rgD-2 vaccine trial outcomes and suggests that ΔgD-2 may prove protective in HSV-1-seropositive hosts.

Enrichment of herpes simplex virus type 2 (HSV-2) reactive mucosal T cells in the human female genital tract

Local mucosal cellular immunity is critical in providing protection from HSV-2. To characterize and quantify HSV-2-reactive mucosal T cells, lymphocytes were isolated from endocervical cytobrush and biopsy specimens from 17 HSV-2-infected women and examined ex vivo for the expression of markers associated with maturation and tissue residency and for functional T-cell responses to HSV-2. Compared with their circulating counterparts, cervix-derived CD4+ and CD8+ T cells were predominantly effector memory T cells (CCR7-/CD45RA-) and the majority expressed CD69, a marker of tissue residency. Co-expression of CD103, another marker of tissue residency, was highest on cervix-derived CD8+ T cells. Functional HSV-2 reactive CD4+ and CD8+ T-cell responses were detected in cervical samples and a median of 17% co-expressed CD103. HSV-2-reactive CD4+ T cells co-expressed IL-2 and were significantly enriched in the cervix compared with blood. This first direct ex vivo documentation of local enrichment of HSV-2-reactive T cells in the human female genital mucosa is consistent with the presence of antigen-specific tissue-resident memory T cells. Ex vivo analysis of these T cells may uncover tissue-specific mechanisms of local control of HSV-2 to assist the development of vaccine strategies that target protective T cells to sites of HSV-2 infection.

Patterns of human herpesvirus-8 oral shedding among diverse cohorts of human herpesvirus-8 seropositive persons

Background

Human herpesvirus-8 (HHV-8), the etiologic agent of Kaposi sarcoma (KS), establishes lifelong latent infection with periodic lytic replication (“shedding”) at mucosal sites, especially the oropharynx. Patterns of HHV-8 shedding are not well understood, and require elucidation to better predict risk of HHV-8 related malignancies in those infected. We sought to characterize patterns of HHV-8 oropharyngeal shedding among diverse cohorts that enrolled HHV-8 seropositive persons.

Methods

We quantified HHV-8 oral shedding using PCR among HHV-8 seropositive persons who collected at least 14 days of oral swabs in 22 studies on 3 continents. We excluded persons taking antivirals during sampling or any prior use of antiretrovirals in those who were HIV-infected.

Results

248 participants were enrolled from the US, Peru, Cameroon, Uganda, and Kenya; 61 % were men, 58 % were HIV seropositive, and 16 % had KS. Overall, 3,123 of 10,557 samples (29.6 %) had HHV-8 detected. Quantity of virus shed was highly correlated with shedding rate, (ρ = 0.72, p < 0.0001). HHV-8 was detected in ≥1 sample in 55 % of participants with a median of 7 % of days in the US and Kenya, 0 % in Uganda and Peru, and 18 % in Cameroon. Median episode duration was three days, and episodes with high median quantity lasted longer (42 vs 3 days, p < 0.0001). In persons with multiple observations over time, 66 % of shedding rate variance was attributable to differences between individuals.

Conclusions

In HHV-8 infected individuals from diverse settings, oral mucosal shedding rate, quantity, and duration were correlated; individual shedding was highly variable. Studies are needed to determine factors accounting for between-person variation and the relationship of HHV-8 shedding to development of associated diseases.

Persistence of mucosal T-cell responses to herpes simplex virus type 2 in the female genital tract

Relatively little is known about the human T-cell response to herpes simplex virus type 2 (HSV-2) in the female genital tract, a major site of heterosexual HSV-2 acquisition, transmission, and reactivation. In order to understand the role of local mucosal immunity in HSV-2 infection, T-cell lines were expanded from serial cervical cytobrush samples from 30 HSV-2-infected women and examined for reactivity to HSV-2. Approximately 3% of the CD3+ T cells isolated from the cervix were HSV-2 specific and of these, a median of 91.3% were CD4+, whereas a median of 3.9% were CD8+. HSV-2-specific CD4+ T cells expanded from the cervix were not only more frequent than CD8+ T cells but also exhibited greater breadth in terms of antigenic reactivity. T cells directed at the same HSV-2 protein were often detected in serial cervical cytobrush samples and in blood. Thus, broad and persistent mucosal T-cell responses to HSV-2 were detected in the female genital tract of HSV-2+ women suggesting that these cells are resident at the site of HSV-2 infection. Understanding the role of these T cells at this biologically relevant site will be central to the elucidation of adaptive immune mechanisms involved in controlling HSV-2 disease.

Conformational analysis, molecular structure and solid state simulation of the antiviral drug acyclovir (zovirax) using density functional theory methods

The five tautomers of the drug acyclovir (ACV) were determined and optimised at the MP2 and B3LYP quantum chemical levels of theory. The stability of the tautomers was correlated with different parameters. On the most stable tautomer N1 was carried out a comprehensive conformational analysis, and the whole conformational parameters (R, β, Φ, φ1, φ2, φ3, φ4, φ5) were studied as well as the NBO Natural atomic charges. The calculations were carried out with full relaxation of all geometrical parameters. The search located at least 78 stable structures within 8.5 kcal/mol electronic energy range of the global minimum, and classified in two groups according to the positive or negative value of the torsional angle j1. In the nitrogen atoms and in the O2' and O5' oxygen atoms of the most stable conformer appear a higher reactivity than in the natural nucleoside deoxyguanosine. The solid state was simulated through a dimer and tetramer forms and the structural parameters were compared with the X-ray crystal data available. Several general conclusions were emphasized.

Cervicovaginal HIV-1 shedding in women taking antiretroviral therapy in Burkina Faso: a longitudinal study

BACKGROUND

Antiretroviral therapy (ART) reduces transmission of HIV-1. However, genital HIV-1 can be detected in patients on ART. We analyzed factors associated with genital HIV-1 shedding among high-risk women on ART in Burkina Faso.

METHODS

Plasma viral load (PVL) and enriched cervicovaginal lavage HIV-1 RNA were measured every 3-6 months for up to 8 years. Random-effects logistic and linear regression models were used to analyze associations of frequency and quantity of genital HIV-1 RNA with behavioral and biological factors, adjusting for within-woman correlation. The lower limit of detection of HIV-1 RNA in plasma and eCVL samples was 300 copies per milliliter.

RESULTS

One hundred and eighty-eight participants initiated ART from 2004 to 2011. PVL was detectable in 16% (171/1050) of visits, in 52% (90/174) of women. Cervicovaginal HIV-1 RNA was detectable in 16% (128/798) of visits with undetectable plasma HIV-1 RNA in 45% (77/170) of women. After adjusting for PVL, detectable cervicovaginal HIV-1 RNA was independently associated with abnormal vaginal discharge and use of nevirapine or zidovudine vs. efavirenz and stavudine, respectively; longer time on ART and hormonal contraception were not associated with increased shedding. The presence of bacterial vaginosis, herpes simplex virus-2 DNA, and the use of nevirapine vs efavirenz were independently associated with an increased quantity of cervicovaginal HIV-1 RNA.

CONCLUSIONS

Certain ART regimens, abnormal vaginal discharge, bacterial vaginosis, and genital herpes simplex virus-2 are associated with HIV-1 cervicovaginal shedding or quantity in women on ART after adjusting for PVL. This may reduce the effectiveness of ART as prevention in high-risk populations.

A combination microbicide gel protects macaques against vaginal simian human immunodeficiency virus-reverse transcriptase infection, but only partially reduces herpes simplex virus-2 infection after a single high-dose cochallenge

Herpes simplex virus-2 (HSV-2) infection increases HIV susceptibility. We previously established a rhesus macaque model of vaginal HSV-2 preexposure followed by cochallenge with HSV-2 and simian/human immunodeficiency virus-reverse transcriptase (SHIV-RT). Using this model, we showed that a gel containing the nonnucleoside reverse transcriptase inhibitor (NNRTI) MIV-150 in carrageenan (CG) reduced SHIV-RT infection. To evaluate the efficacy of new generation microbicides against both viruses, we first established dual infection after single vaginal cochallenge with SHIV-RT and HSV-2 in HSV-2-naive macaques. All animals (6/6) became HSV-2 infected, with 4/6 coinfected with SHIV-RT. In a control group cochallenged with SHIV-RT and UV-inactivated HSV-2, 2/4 became SHIV-RT infected, and none had detectable HSV-2. Low-level HSV-2-specific antibody and T cell responses were detected in some HSV-2-infected animals. To test a CG gel containing MIV-150 and zinc acetate (MZC), which provided naive animals full protection from SHIV-RT for at least 8 h, MZC (vs. CG) was applied daily for 14 days followed by cochallenge 8 h later. MZC prevented SHIV-RT infection (0/9 infected, p=0.04 vs. 3/6 in CG controls), but only reduced HSV-2 infection by 20% (6/9 infected vs. 5/6 in CG, p=0.6). In HSV-2-infected animals, none of the gel-treated animals seroconverted, and only the CG controls had measurable HSV-2-specific T cell responses. This study shows the promise of MZC to prevent immunodeficiency virus infection (even in the presence of HSV-2) and reduce HSV-2 infection after exposure to a high-dose inoculum. Additionally, it demonstrates the potential of a macaque coinfection model to evaluate broad-spectrum microbicides.

Silicone-acyclovir controlled release devices suppress primary herpes simplex virus-2 and varicella zoster virus infections in vitro

Following initial infection, herpesviruses retreat into a permanent latent state with periodic reactivation resulting in an enhanced likelihood of transmission and clinical disease. The nucleoside analogue acyclovir reduces clinical symptoms of the three human alpha herpesviruses, HSV-1, HSV-2, and VZV. Long-term administration of acyclovir (ACV) can reduce the frequency and severity of reactivation, but its low bioavailability and short half-life require a daily drug regimen. Our lab is working to develop a subcutaneous delivery system to provide long-lasting, sustained release of ACV. Previously, we demonstrated that an implantable silicone (MED-4050) device, impregnated with ACV protected against HSV-1 both in vitro and in vivo. Here, we extend our in vitro observations to include protection against both HSV-2 and VZV. We also demonstrate protection against HSV-2 in vitro using MED-4750, a silicone polymer designed for long-term use in humans. When release of ACV from MED-4750 is quantitated on a daily basis, an initial burst of 5 days is observed, followed by a long period of slow release with near-zero-order kinetics, with an average daily release of 1.3923 ± 0.5908 μg ACV over days 20–60. Development of a slow-release implant has the potential to significantly impact the treatment of human alpha herpesvirus infections.

High-dose valacyclovir decreases plasma HIV-1 RNA more than standard-dose acyclovir in persons coinfected with HIV-1 and HSV-2: a randomized crossover trial

BACKGROUND

Standard doses of herpes simplex virus (HSV) suppressive therapy reduce plasma HIV-1 RNA levels (0.25-0.53 log10 copies per milliliter) among HIV-1/HSV-2 coinfected persons. Postulated mechanisms for this effect include direct inhibition of HIV-1 by acyclovir or indirect reduction by decreasing HSV-associated inflammation. We hypothesized that high-dose valacyclovir would further reduce plasma HIV-1 RNA and that the effect would be mediated by greater suppression of HSV shedding.

METHODS

Thirty-four participants with HIV-1 and HSV-2 not on antiretroviral therapy were enrolled into a randomized, open-label crossover trial of valacyclovir 1000 mg twice daily or acyclovir 400 mg twice daily for 12 weeks, followed by a 2-week washout, and then the alternate treatment arm for 12 weeks. HSV DNA was measured from daily self-collected genital swabs for the initial 4 weeks of each arm, and HIV-1 RNA was quantified from weekly plasma samples.

RESULTS

Twenty-eight participants provided plasma samples and genital swabs on both acyclovir and valacyclovir. The genital HSV-2 shedding rate was the same on valacyclovir and acyclovir [7.8% vs. 8.2% of days; relative risk: 0.95; 95% confidence interval (CI): 0.66 to 1.37; P = 0.78]. Plasma HIV-1 RNA was 0.27 log10 copies per milliliter lower on valacyclovir compared with acyclovir (95% CI: -0.41 to -0.14 log10 copies per milliliter; P < 0.001); this was unchanged after adjustment for genital HSV-2 shedding.

CONCLUSIONS

High-dose valacyclovir reduces plasma HIV-1 RNA levels more than standard-dose acyclovir in HIV-1/HSV-2-seropositive persons not receiving antiretroviral therapy. The incremental reduction in plasma HIV-1 RNA achieved is not mediated by greater genital HSV-2 suppression.

Changes in the soluble mucosal immune environment during genital herpes outbreaks

BACKGROUND

Genital tract secretions provide variable inhibitory activity against herpes simplex virus (HSV) ex vivo. We hypothesize that the anti-HSV activity may prevent the spread of virus from the more commonly affected sites, such as the external genitalia, to the upper genital tract.

METHODS

The antimicrobial activity of cervicovaginal lavage (CVL) and concentrations of mucosal immune mediators were measured in 10 HIV-seronegative women with an active external herpetic lesion and compared with 10 HIV-seronegative women who were HSV-1 and HSV-2 seronegative. Samples were obtained at the time of a symptomatic external lesion (day 0), after 1 week of oral acyclovir (day 7), and 1 week after completing treatment (day 14). Controls were evaluated at parallel intervals.

RESULTS

The anti-HSV activity was higher in CVL obtained from cases compared to controls at presentation (day 0) (54.3% vs. 28%), fell to similar levels on day 7, and then rebounded on day 14 (69% vs. 25%). The anti-HSV activity correlated positively and significantly with the concentrations of several inflammatory proteins; the concentrations of these proteins tended to be higher in cases compared with controls and followed a similar temporal pattern.

CONCLUSIONS

Increases in inflammatory immune mediators and anti-HSV activity were detected in CVL at the time of clinical outbreaks and after completion of a short course of acyclovir. These mucosal responses may protect against HSV spread but could facilitate HIV infection and contribute to the clinical observation that, independent of clinical lesions, HSV-2 is a risk factor for HIV acquisition.

In vitro antiviral activity of dermaseptin S(4) and derivatives from amphibian skin against herpes simplex virus type 2

Herpes simplex virus (HSV) infections have become a public health problem worldwide. The emergence of acyclovir-resistant viral strains and the failure of vaccination to prevent herpetic infections have prompted the search for new antiviral drugs. Accordingly, the present study was undertaken to synthesize chemically and evaluate Dermaseptin S(4) (S(4)), an anti-microbial peptide derived from amphibian skin, and its derivatives in terms of anti-herpetic activity. The effects of biochemical modifications on their antimicrobial potential were also investigated. The peptides were incubated together with HSV-2 on target cells under various conditions, and the antiviral effects were examined via a cell metabolic labeling method. The findings revealed that DS(4) derivatives elicited concentration-dependent antiviral activity at micromole concentrations. The biochemical modifications of S(4) allowed for the reduction of peptide cytotoxicity without altering antiviral activity. Dermaseptins were added at different times during the viral cycle to investigate the mode of antiviral action. At the highest non-cytotoxic concentrations, most of the tested derivatives were noted to exhibit high antiviral activity particularly when pre-incubated with free herpes viruses prior to infection. Among these peptides, K(4)K(20)S(4) exhibited the highest antiviral activity against HSV-2 sensitive and resistant strains. Interestingly, the antiviral activity of K(4)K(20)S(4) was effective on both acyclovir-resistant and -sensitive viruses. The findings indicate that K(4)K(20)S(4) can be considered a promising candidate for future application as a therapeutic virucidal agent for the treatment of herpes viruses.