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.     

Cross protective efficacy of the Non-Neurotropic live attenuated herpes simplex virus type 1 vaccine VC-2 is enhanced by intradermal vaccination and deletion of glycoprotein G

Herpes simplex virus type 1 and 2 (HSV-1 and HSV-2 respectively) cause life-long latent infections resulting in recurrent orofacial and genital blisters or sores. Ensued disease can be painful and may lead to significant mental anguish of infected individuals. Currently, there are no FDA-approved vaccines for either prophylactic or therapeutic use, and recent clinical trials of subunit vaccines failed to achieve endpoints goals. Development of a safe live-attenuated herpes simplex vaccine may provide the antigenic breadth to ultimately protect individuals from acquiring HSV disease. We have previously shown that prophylactic use of the non-neurotropic live attenuated HSV-1 vaccine, VC-2, provides potent and durable protection from genital HSV-2 disease in the guinea pig model. Here, we investigated the effects of intradermal administration as well as the deletion of the viral glycoprotein G (gG) on the efficacy of prophylactic vaccination. Vaccination with either VC-2, VC-2 gG null, or gD2 MPL/Alum offered robust protection from acute disease regardless of route of vaccination. However, both the VC-2 gG-null and the ID vaccination route were more effective compared to the parent VC2 administered by the IM route. Specifically, the VC-2 gG-null administered ID, reduced HSV-2 vaginal replication on day 2 and day 4 as well as mean recurrent lesion scores more effectively than VC2 administered IM. Most importantly, only VC-2 gG null IM and VC-2 ID significantly reduced the frequency of recurrent shedding, the most likely source for virus transmission. Similarly, while all vaccinated groups demonstrated a significant reduction in the number of animals testing PCR-positive for HSV-2 in their dorsal root ganglia following challenge only VC2 ID vaccinated animals demonstrated a significant reduction in DRG viral load. All vaccinations induced neutralizing antibodies to HSV-2 MS when compared to unvaccinated guinea pigs. Therefore, further investigation of VC-2 gG null delivered ID is warranted.     

A Vaxfectin-adjuvanted HSV-2 plasmid DNA vaccine is effective for prophylactic and therapeutic use in the guinea pig model of genital herpes

Here we describe studies in the guinea pig model of genital herpes to evaluate a novel plasmid DNA (pDNA) vaccine encoding the HSV-2 glycoprotein D and UL46 and UL47 genes encoding tegument proteins VP11/12 and VP 13/14 (gD2/UL46/UL47), formulated with a cationic lipid-based adjuvant Vaxfectin^®. Prophylactic immunization with Vaxfectin^®-gD2/UL46/UL47 significantly reduced viral replication in the genital tract, provided complete protection against both primary and recurrent genital skin disease following intravaginal HSV-2 challenge, and significantly reduced latent HSV-2 DNA in the dorsal root ganglia compared to controls. We also examined the impact of therapeutic immunization of HSV-2 infected animals. Here, Vaxfectin^®-gD2/UL46/UL47 immunization significantly reduced both the frequency of recurrent disease and viral shedding into the genital tract compared to controls. This novel adjuvanted pDNA vaccine has demonstrated both prophylactic and therapeutic efficacy in the guinea pig model of genital herpes and warrants further development.     

Effect of route of vaccination with vaccinia virus expressing HSV-2 glycoprotein D on protection from genital HSV-2 infection

To evaluate the effects of the route of vaccination on protection against genital HSV infection guinea pigs were vaccinated twice with vaccinia recombinants expressing HSV-2 glycoprotein D or controls by intradermal, intranasal or intravaginal inoculation. Following HSV-2 intravaginal challenge, immunization by all 3 routes reduced vaginal HSV shedding and acute genital disease. The intravaginal vaccination, however, most effectively reduced primary and recurrent HSV disease. Vaccinia and HSV antibody titers were similar in all vaccinia gD immunized groups while the lymphoproliferative response was highest in the intradermal group. In a smaller follow-up experiment we demonstrated that intrarectal immunization with vaccinia gD could also induce antibody and T cell responses.     

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.     

Intranasal nanoemulsion-adjuvanted HSV-2 subunit vaccine is effective as a prophylactic and therapeutic vaccine using the guinea pig model of genital herpes

Genital herpes is a sexually transmitted disease representing a major global health concern. Currently, there is no approved vaccine and existing antiviral therapies exhibit limited efficacy. Herein, we describe an intranasal (IN) vaccine comprised of HSV-2 surface glycoproteins gD2 and gB2 formulated in a nanoemulsion adjuvant (NE01-gD2/gB2). Using the HSV-2 genital herpes guinea pig model, we demonstrate that IN NE01-gD2/gB2 induces higher levels of neutralizing antibody compared to a monovalent IN NE01-gD2 vaccine, but less than an intramuscular (IM) Alum/MPL-gD2 vaccine. Following intravaginal (IVag) challenge with HSV-2, the group immunized with IN NE01-gD2/gB2 exhibited significantly reduced acute and recurrent disease scores compared to placebo recipients. Significantly, latent virus was only detected in the dorsal root ganglia of 1 of 12 IN NE01-gD2/gB2-vaccinated animals compared to 11 of 12 placebo recipient. In the therapeutic model, IN NE01-gD2/gB2 immunized guinea pigs exhibited a significant reduction in the recurrent lesions scores (64%, p < 0.01), number of animal days with disease (64%, p < 0.01), number of animals with viral shedding (50%, p < 0.04) and reduction in virus positive vaginal swabs (56%, p < 0.04), These data suggests that the treatment may be effective in treating chronic disease and minimizing virus transmission. These results warrant advancing the development of IN NE01-gD2/gB2 as both a prophylactic and therapeutic vaccine against HSV-2.     

Inactivated HSV-2 in MPL/alum adjuvant provides nearly complete protection against genital infection and shedding following long term challenge and rechallenge

Herpes Simplex Virus Type 2 (HSV-2) infection can result in life-long recurrent genital disease, asymptomatic virus shedding, and transmission. No vaccine to date has shown significant protection clinically. Here, we used a mouse model of genital HSV-2 infection to test the efficacy of a vaccine consisting of whole, formalin-inactivated HSV-2 (FI-HSV2) formulated with monophosphoryl lipid A (MPL) and alum adjuvants. Vaccine components were administered alone or as a prime-boost immunization together with DNA vaccines encoding a truncated glycoprotein D2 (gD2t) and two conserved HSV-2 genes necessary for virus replication, UL5 (DNA helicase) and UL30 (DNA polymerase). Our results show: (1) compared with mock immunized controls, mice immunized with FI-HSV2 plus MPL/alum consistently showed protection against disease burden and total viral shedding while the mice immunized with gD2t protein with MPL/alum did not; (2) protection against genital disease and viral replication correlated with the type of boost in a prime-boost immunization with little advantage afforded by a DNA prime; (3) intramuscular (i.m.) immunization with FI-HSV2 in MPL/Alhydrogel adjuvant provided nearly complete protection against vaginal HSV-2 shedding after a lethal intravaginal (i.vag.) short-term challenge and long-term rechallenge; (4) single formulation immunization with DNA vaccines, FI-HSV2, and MPL in an aluminum phosphate (Adju-Phos) adjuvant did not increase protection relative to FI-HSV2/MPL/Adju-Phos alone; and (5) addition of MPL/alum to the FI-HSV2 was required for optimal protection against disease, viral replication, and latent virus load in the dorsal root ganglia (DRG). Most notably, an optimized vaccine formulation of FI-HSV2 MPL/Alhydrogel given i.m. completely protected against detectable vaginal HSV-2 shedding in the majority of animals and HSV-2 latent DNA in the DRG of all animals.     

A novel HSV-2 subunit vaccine induces GLA-dependent CD4 and CD8 T cell responses and protective immunity in mice and guinea pigs

Background/objectivesThere is currently no licensed prophylactic or therapeutic vaccine for HSV-2 infection.MethodsWe developed a novel preclinical vaccine candidate, G103, consisting of three recombinantly expressed HSV-2 proteins (gD and the UL19 and UL25 gene products) adjuvanted with the potent synthetic TLR4 agonist glucopyranosyl lipid A (GLA) formulated in stable emulsion. The vaccine was tested for immunogenicity and efficacy in pre-clinical models for preventative and therapeutic vaccination.ResultsVaccination of mice with G103 elicited antigen-specific binding and neutralizing antibody responses, as well as robust CD4 and CD8 effector and memory T cells. The T cell responses were further boosted by subsequent challenge with live virus. Prophylactic immunization completely protected against lethal intravaginal HSV-2 infection in mice, with only transient replication of virus in the genital mucosa and sterilizing immunity in dorsal root ganglia. Supporting the use of G103 therapeutically, the vaccine expanded both CD4 and CD8 T cells induced in mice by previous infection with HSV-2. In the guinea pig model of recurrent HSV-2 infection, therapeutic immunization with G103 was approximately 50% effective in reducing the number of lesions per animal as well as the overall lesions score.ConclusionsTaken together, the data show that G103 is a viable candidate for development of a novel prophylactic and therapeutic HSV-2 vaccine.     

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.     

Effects of DNA immunization formulated with bupivacaine in murine and guinea pig models of genital herpes simplex virus infection

The immunogenicity and efficacy of a herpes simplex virus type 2 glycoprotein D (gD2) DNA vaccine formulated with bupivacaine was evaluated using murine and guinea pig models of genital herpes. Animals received three doses of 100 microg of gD2 plasmid or control plasmid intramuscularly prior to intravaginal challenge with HSV-2. Immunization induced HSV ELISA and neutralizing antibody in serum and ELISA antibody in the vaginal secretions of all animals evaluated. Following intravaginal HSV-2 challenge, vaginal viral replication was reduced in both models with peak reductions of greater than 99%. Immunization also decreased the number of animals developing any clinical disease (p < 0.001) and the severity of the acute disease (total lesion score 6.4 versus 0.6 in guinea pigs, p < 0.001). Further recurrent lesion days were reduced from 14.5 to 4.9 days in immunized guinea pigs (p < 0.001). DNA immunization with gD2 + bupivacaine was effective in reducing clinical disease and viral replication in both guinea pigs and mice.     

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.     

Therapeutic HSV-2 vaccine decreases recurrent virus shedding and recurrent genital herpes disease

BackgroundGenital herpes simplex virus (HSV) type 2 is a common persistent infection that frequently reactivates to cause recurrent lesions and recurrent viral shedding which is incompletely controlled by antiviral therapy. GEN-003 is a candidate therapeutic vaccine containing 2 HSV-2 proteins, gD2 and ICP4, and Matrix-M2 adjuvant (M2).MethodsHSV-2 seropositive persons with genital herpes were randomized into three dose cohorts of Gen-003 (60 µg antigen/50 µg M2, 60 µg/75 µg M2 or Placebo). Three intramuscular doses 21 days apart of GEN-003 or placebo were administered. Participants obtained genital area swabs twice-daily for HSV-2 detection and monitored genital lesions for 12 months. The rates of virus shedding and lesion rates before vaccination were compared to 3 defined periods after vaccination; Days 43–71, Month 6 and Month 12.ResultsGEN-003 at a dose of 60 µg each antigen/50 µg M2 reduced HSV shedding immediately after dosing with a rate ratio of 0.58, compared to 0.75 for the GEN-003 60 µg/75 µg M2 and 1.06 for placebo. Lesion rates, recurrence rates, and duration of recurrences were also reduced. Reactogenicity was higher with the 75 µg M2 dose than the 50 µg M2 dose, specifically for pain, tenderness, malaise and fatigue. Antibody and cellular immune responses were stimulated by both doses and persisted to 12 months.ConclusionsGEN-003 vaccine manufactured with a scalable process gave results similar to those observed in prior clinical trials. GEN-003 had an acceptable safety profile and stimulated both humoral and cellular immune responses. The 60 µg antigen/50 µg M2 provided the maximal effect on virologic and clinical measures and warrants further development. (Funded by Genocea; ClinicalTrials.gov number NCT02515175).     

Vaccination with a HSV-2 UL24 mutant induces a protective immune response in murine and guinea pig vaginal infection models

The rational design and development of genetically attenuated HSV-2 mutant viruses represent an attractive approach for developing both prophylactic and therapeutic vaccines for genital herpes. Previously, HSV-2 UL24 was shown to be a virulence determinant in both murine and guinea pig vaginal infection models. An UL24-βgluc insertion mutant produced syncytial plaques and replicated to nearly wild type levels in tissue culture, but induced little or no pathological effects in recipient mice or guinea pigs following vaginal infection. Here we report that immunization of mice or guinea pigs with high or low doses of UL24-βgluc elicited a highly protective immune response. UL24-βgluc immunization via the vaginal or intramuscular routes was demonstrated to protect mice from a lethal vaginal challenge with wild type HSV-2. Moreover, antigen re-stimulated splenic lymphocytes harvested from immunized mice exhibited both HSV-2 specific CTL activity and IFN-γ expression. Humoral anti-HSV-2 responses in serum were Th1-polarized (IgG_2a > IgG₁) and contained high-titer anti-HSV-2 neutralizing activity. Guinea pigs vaccinated subcutaneously with UL24-βgluc or the more virulent parental strain (186) were challenged with a heterologous HSV-2 strain (MS). Acute disease scores were nearly indistinguishable in guinea pigs immunized with either virus. Recurrent disease scores were reduced in UL24-βgluc immunized animals but not to the same extent as those immunized with strain 186. In addition, challenge virus was not detected in 75% of guinea pigs subcutaneously immunized with UL24-βgluc. In conclusion, disruption of the UL24 gene is a prime target for the development of a genetically attenuated live HSV-2 vaccine.     

A heat shock protein based polyvalent vaccine targeting HSV-2: CD4 and CD8 cellular immunity and protective efficacy

Efforts to develop a subunit vaccine against genital herpes have been hampered by lack of knowledge of the protective antigens of HSV-2, the causative agent of the disease. Vaccines based either on selected antigens or attenuated live virus approaches have not demonstrated meaningful clinical activity. We present here results of a therapeutic vaccine candidate, HerpV (formerly called AG-707), consisting of 32 HSV-2 peptides derived from 22 HSV-2 proteins, complexed non-covalently to the HSP70 chaperone and formulated with QS-21 saponin adjuvant. HerpV is observed to be immunogenic, generating CD4⁺ and CD8⁺ T cell responses in three mouse strains including HLA-A2 transgenic mice. Optimal T cell stimulation was dependent on the synergistic adjuvant properties of QS-21 with hsp70. The vaccine provided significant protection from viral challenge in a mouse prophylaxis model and showed signals of activity in a guinea pig therapeutic model of existing infection. Peripheral blood mononuclear cells from human HSV-2⁺ subjects also showed reactivity in vitro to a subset of individual peptides and to the pool of all 32 peptides. Recombinant human Hsc70 complexed with the 32 peptides also stimulated the expansion of CD8⁺ T cells from HSV-2⁺ subjects in vitro. These studies demonstrate that HerpV is a promising immunotherapy candidate for genital herpes, and provide a foundation for evaluating HerpV in human HSV-2⁺ subjects with the intent of eliciting CD4⁺ and CD8⁺ T cell responses to a broad array of viral antigens.     

Inflammatory parameters associated with systemic reactogenicity following vaccination with adjuvanted hepatitis B vaccines in humans

Background

Adjuvants like AS01_B increase the immunogenicity of vaccines and generally cause increased transient reactogenicity compared with Alum. A phase II randomized trial was conducted to characterize the response to AS01_B and Alum adjuvanted vaccines. A post-hoc analysis was performed to examine the associations between reactogenicity and innate immune parameters.

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.     

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.     

A randomized,double-blind,controlled clinical trial to evaluate the safety and immunogenicity of an intranasally administered trivalent inactivated influenza vaccine with adjuvant LTh(αK): A phase I study

Background

A nasal influenza vaccine has been available only in a live attenuated form, which limits the range of recipients to immune-competent individuals. The present study evaluated a newly developed intranasal inactivated influenza vaccine with a novel adjuvant, heat-labile enterotoxin (LT) derived from E. coli (LTh(αK)).

Development of a therapeutic vaccine for HSV-2

A therapeutic vaccine for genital herpes is clearly needed. Vaccines recently developed for HSV-2 in humans have been aimed at eliciting CD4+ T cell responses and neutralizing antibody responses to two HSV-2 glycoproteins (gB and gD). These vaccines have had no therapeutic effect against HSV-2 in human clinical trials. To enable development of an efficacious vaccine, Corixa Corporation has made a major effort to identify novel antigens that can be recognized by human HSV-2-specific CD8+ and CD4+ T cells. Corixa Corporation's proprietary adjuvants and delivery systems, when combined with appropriate antigens, may allow the development of an effective therapeutic vaccine for HSV-2.     

Vaccine health beliefs and educational influences among pediatric residents

Objective

A pilot study of pediatric residents to describe perceived benefits and effects of vaccines and educational influences on vaccine practice among pediatric residents.