Herpes Simplex Virus Type 1 gD Research Articles

Comparison of effects of multiple adjuvants and immunization routes on the immunogenicity and protection of HSV-2 gD subunit vaccine

Genital herpes caused by herpes simplex virus type 2 (HSV-2) poses a global health issue. HSV-2 infection increases the risk of acquiring HIV infection. Studies have demonstrated that HSV-2 subunit vaccines have potential benefits, but require adjuvants to induce a balanced Th1/Th2 response. To develop a novel, effective vaccine, in this study, a truncated glycoprotein D (aa 1–285) of HSV-2 was formulated with an Al(OH)3 adjuvant, three squalene adjuvants, zMF59, zAS03, and zAS02, or a mucosal adjuvant, bacterium-like particles (BLPs). The immunogenicity of these subunit vaccines was evaluated in mice. After three immunizations, vaccines formulated with Al(OH)3, zMF59, zAS03, and zAS02 (intramuscularly) induced higher titers of neutralizing antibody than that formulated without adjuvant, and in particular, mice immunized with the vaccine plus zAS02 had the highest neutralizing antibody titers and tended to produce a more balanced immune reaction than others. Intranasal gD2-PA-BLPs also induced excellent IgA levels and a more balanced Th1 and Th2 responses than intranasal gD2. After challenge with a lethal dose of HSV-2, all five adjuvants exhibited a positive effect in improving the survival rate. zAS02 and gD2-PA-BLPs enhanced survival by 50% and 25%, respectively, when compared with the vaccine without adjuvant. zAS02 was the only adjuvant that resulted in complete vaginal virus clearance and genital lesion healing within eight days. These results demonstrate the potential of using zAS02 as a subunit vaccine adjuvant, and BLPs as a mucosal vaccine adjuvant.

Antiviral Effect of Polyphenolic Substances in Geranium wilfordii Maxim against HSV-2 Infection Using in vitro and in silico Approaches.

Background Herpes simplex virus type 2 (HSV-2) infestation was the most widespread STD (sexually transmitted diseases) among humans and was the leading cause of infectious recurrent genital herpes. Existing therapies against HSV-2 did incompletely restrain the comeback of activated HSV-2 infestation. Geranium wilfordii Maxim had long been used as traditional Chinese medicine for treating the diseases owing to its anti-inflammatory and antiviral effects. Herein, the study was designed to investigate the antiviral activity of G.wilfordii and its potential effect in regulating the host's immune response. Methods To identify the stage of infection at which the compounds inhibited HSV-2, we performed virucidal, therapeutic, and prophylactic assays. The antiviral efficacy was evaluated by the analysis of viral components HSV-2 gD and VP16. The antiviral activities of these compounds were also evaluated by phenotypic analysis, such as cell proliferation and apoptosis. Molecular docking studies on candidate compounds were done to indicate binding interactions between the compounds and adopted compound targets. Results Quercetin, corilagin, and geraniin inhibited the replication of HSV-2, with geraniin showing greater TI. The obtained IC50 value of quercetin was 204.7 μM and TI (IC50/EC50) was 5.1, whereas the obtained IC50 value of corilagin was 118.0 μg/ml and TI was 4.05. Geraniin exhibited prominent antiviral activity with an IC50 of 212.4 μM and an EC50 of 18.37 μM, resulting in a therapeutic index (TI) of 11.56. Geraniin showed important in vitro virucidal activity through blocking viral attachment. Compared with the virus group, the apoptosis rates in quercetin-, corilagin-, and geraniin-treated groups were significantly decreased (p < 0.001).The expressions at the transcription genes of virus own replication key factors (including HSV-2 gD and VP16) and cytokines (including TBK1) of infected cells treated with quercetin, corilagin, and geraniin were inhibited. The in silico approaches demonstrated a high number of potential strong intermolecular interactions as hydrogen bonds between geraniin, corilagin, and the activity site of HSV-2 gD. Molecular docking studies demonstrated the effects of corilagin by targeting TBK1. Conclusions Together, these results highlighted the importance of G.wilfordii treatment in HSV-2 infection and underscored its therapeutic potential. However, additional in vitro and in vivo research was required to validate our findings.

Application of Mucosal Immune-related Molecular Adjuvants CCL19 and CCL28 in Enhancing the Function of HSV-2 gD DNA Vaccine

Herpes simplex virus type 2 (HSV-2) develops an annual incidence of 2.3 million people worldwide, which can lead to life-long latent infections, asymptomatic and reactivations and with occasional symptomatic episodes causing ulcerative lesions in the genitalia and naus.

Serum and Cervicovaginal Fluid Antibody Profiling in Herpes Simplex Virus-Seronegative Recipients of the HSV529 Vaccine.

Previous herpes simplex virus type 2 (HSV-2) vaccines have not prevented genital herpes. Concerns have been raised about the choice of antigen, the type of antibody induced by the vaccine, and whether antibody is present in the genital tract where infection occurs. We reported results of a trial of an HSV-2 replication-defective vaccine, HSV529, that induced serum neutralizing antibody responses in 78% of HSV-1-/HSV-2- vaccine recipients. Here we show that HSV-1-/HSV-2- vaccine recipients developed antibodies to epitopes of several viral proteins; however, fewer antibody epitopes were detected in vaccine recipients compared with naturally infected persons. HSV529 induced antibodies that mediated HSV-2-specific natural killer (NK) cell activation. Depletion of glycoprotein D (gD)-binding antibody from sera reduced neutralizing titers by 62% and NK cell activation by 81%. HSV-2 gD antibody was detected in cervicovaginal fluid at about one-third the level of that in serum. A vaccine that induces potent serum antibodies transported to the genital tract might reduce HSV genital infection.

Scrutiny of the mechanism of β-amyloid protein captures HSV-2 to protect the brain infection

Alzheimer’s disease (AD) is an age-related neurodegenerative disorder. β-amyloid protein (Aβ) is the key protein which involved in AD. But the physiological function of Aβ is needed to be investigated. Many experimental studies have shown that Aβ could bind to glycoproteins D (gD) on the surface of the herpes virus. However the mechanism is still unclear. In the present study, we elucidate the molecular mechanism of the interaction between Aβ and gD of herpes simplex virus type 2 (HSV-2) by molecular docking and molecular dynamics simulation. Molecular dynamics simulations displayed that Aβ could stably bind to the HSV-2 gD owing to the presence of several interactions. Analysis binding free energy by molecular mechanics Poisson–Boltzmann surface area (MM–PBSA) method revealed that hot residues including Glu3, Glu11, Glu22 and Ala42 of Aβ1-42 were involved in binding with HSV-2 gD. Thus, the HSV-2 gD can be entrapped by Aβ which will be utilized for prevent and therapy of AD in future.

US6 Gene Deletion in Herpes Simplex Virus Type 2 Enhances Dendritic Cell Function and T Cell Activation.

Herpes simplex virus (HSV) type 1 (HSV-1) and type 2 (HSV-2) produce lifelong infections that are associated with frequent asymptomatic or clinically apparent reactivation. Importantly, HSV express multiple virulence factors that negatively modulate innate and adaptive immune components. Notably, HSV interfere with dendritic cell (DC) viability and function, likely hindering the capacity of the host to mount effective immunity against these viruses. Recently, an HSV-2 virus that was deleted in glycoprotein D was engineered (designated ΔgD-2). The virus is propagated on a complementing cell line that expresses HSV-1 gD, which permits a single round of viral replication. ΔgD-2 is safe, immunogenic, and provided complete protection against vaginal or skin challenges with HSV-1 and HSV-2 in murine models. Here, we sought to assess the interaction of ΔgD-2 with DCs and found that, in contrast to wild-type (WT) virus which induces DC apoptosis, ΔgD-2 promoted their migration and capacity to activate naïve CD8+ and CD4+ T cells in vitro and in vivo. Furthermore, DCs exposed to the WT and ΔgD-2 virus experienced different unfolded protein responses. Mice primed with DCs infected with ΔgD-2 in vitro displayed significantly reduced infection and pathology after genital challenge with virulent HSV-2 compared to non-primed mice, suggesting that DCs play a role in the immune response to the vaccine strain.

Targeting Herpes Simplex Virus-1 gD by a DNA Aptamer Can Be an Effective New Strategy to Curb Viral Infection.

Herpes simplex virus type 1 (HSV-1) is an important factor for vision loss in developed countries. A challenging aspect of the ocular infection by HSV-1 is that common treatments, such as acyclovir, fail to provide effective topical remedies. Furthermore, it is not very clear whether the viral glycoproteins, required for HSV-1 entry into the host, can be targeted for an effective therapy against ocular herpes in vivo. Here, we demonstrate that HSV-1 envelope glycoprotein gD, which is essential for viral entry and spread, can be specifically targeted by topical applications of a small DNA aptamer to effectively control ocular infection by the virus. Our 45-nt-long DNA aptamer showed high affinity for HSV-1 gD (binding affinity constant [Kd] = 50 nM), which is strong enough to disrupt the binding of gD to its cognate host receptors. Our studies showed significant restriction of viral entry and replication in both in vitro and ex vivo studies. In vivo experiments in mice also resulted in loss of ocular infection under prophylactic treatment and statistically significant lower infection under therapeutic modality compared to random DNA controls. Thus, our studies validate the possibility that targeting HSV-1 entry glycoproteins, such as gD, can locally reduce the spread of infection and define a novel DNA aptamer-based approach to control HSV-1 infection of the eye.

A novel vaccine vector: herpes simplex virus type-2 deleted in glycoprotein D (HSV-2 ΔgD) and expressing modified influenza A (IAV) hemagglutinin (HA) antigens

Abstract Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) cause significant global morbidity and mortality. In collaboration, the Jacobs and Herold laboratories generated an attenuated herpes simplex virus type 2 (HSV-2) strain deleted in glycoprotein D (HSV-2 ΔgD) and demonstrated that it triggers an FcγRIV activating response that elicits both antibody-dependent cell-mediated cytotoxicity and phagocytosis. The antibodies rapidly clear virus and prevent the establishment of latency in mice and guinea pigs following challenge with several clinical isolates of both HSV-1 and HSV-2. We therefore propose that HSV-2 ΔgD is an ideal vaccine vector to induce immunity against a wide array of pathogens. The HSV genome is difficult to work with due to high GC content, repetitive regions, and tendency toward attenuation. Using Gibson cloning and homologous recombination we introduce exogenous genes such as red fluorescent protein (rfp) and influenza A (IAV) hemagglutinin (HA) into the HSV genome. IAV HA is a great model antigen to study the immunogenicity of proteins inserted into the HSV-2 ΔgD backbone. Moreover, cloning both full-length and stalk HAs into the HSV-2 ΔgD genome will test the influence of immunodominant antigens on the character of our antibody response. Our expression vectors, verified by digestion and sequencing, encode a chimeric gD/HA protein that contains the signal sequence and cytosolic and transmembrane domains of HSV-2 gD. These modifications will promote trafficking of HA to the cell membrane and viral envelope. Our recombination system has produced an RFP+ HSV-2 ΔgD virus that we verified by fluorescence, digestion and sequencing. The kinetics of infection with the RFP+ virus match that its parental HSV-2 ΔgD strain.

Distribution of cellular HSV-1 receptor expression in human brain

Herpes simplex virus type 1 (HSV-1) is a neurotropic virus linked to a range of acute and chronic neurological disorders affecting distinct regions of the brain. Unusually, HSV-1 entry into cells requires the interaction of viral proteins glycoprotein D (gD) and glycoprotein B (gB) with distinct cellular receptor proteins. Several different gD and gB receptors have been identified, including TNFRSF14/HVEM and PVRL1/nectin 1 as gD receptors and PILRA, MAG, and MYH9 as gB receptors. We investigated the expression of these receptor molecules in different areas of the adult and developing human brain using online transcriptome databases. Whereas all HSV-1 receptors showed distinct expression patterns in different brain areas, the Allan Brain Atlas (ABA) reported increased expression of both gD and gB receptors in the hippocampus. Specifically, for PVRL1, TNFRFS14, and MYH9, the differential z scores for hippocampal expression, a measure of relative levels of increased expression, rose to 2.9, 2.9, and 2.5, respectively, comparable to the z score for the archetypical hippocampus-enriched mineralocorticoid receptor (NR3C2, z = 3.1). These data were confirmed at the Human Brain Transcriptome (HBT) database, but HBT data indicate that MAG expression is also enriched in hippocampus. The HBT database allowed the developmental pattern of expression to be investigated; we report that all HSV1 receptors markedly increase in expression levels between gestation and the postnatal/adult periods. These results suggest that differential receptor expression levels of several HSV-1 gD and gB receptors in the adult hippocampus are likely to underlie the susceptibility of this brain region to HSV-1 infection.

Rapid Screening by Cell-Based Fusion Assay for Identifying Novel Antivirals of Glycoprotein B-Mediated Herpes Simplex Virus Type 1 Infection.

Herpes simplex virus type 1 (HSV-1) is a causative agent for a variety of diseases. Although antiherpetic drugs such as acyclovir have been developed to inhibit virus replication through interaction with DNA kinases, their continuous administration leads to an increase in the frequency of drug-resistant HSV-1, which is an important clinical issue that requires urgent solution. Recently, we reported that the sialylated O-linked sugar T antigen (sTn) and its attached peptide region (O-glycosylated sTn peptide) derived from the HSV-1 glycoprotein B (gB) protein inhibited HSV-1 infection by specifically targeting paired immunoglobulin-like type 2 receptor alpha (PILRα) in vitro. In this study, to further identify novel inhibitors of gB-mediated HSV-1 infection in vitro, we established a cell-based fusion assay for rapid drug screening. Chinese hamster ovary (CHO) cells were transfected with expression plasmids for HSV-1 gB, gD, gH, and gL, and T7 RNA polymerase, and were designated as the effector cells. The CHO-K1 cells stably expressing PILRα were transfected with the expression plasmid for firefly luciferase under the T7 promoter, and were designated as the target cells. The effector and target cells were co-cultured, and luminescence was measured when both cells were successfully fused. Importantly, we found that cell-to-cell fusion was specifically inhibited by O-glycosylated sTn peptide in a dose dependent manner. Our results suggested that this virus-free cell-based fusion assay system could be a useful and promising approach to identify novel inhibitors of gB-mediated HSV-1 infection, and will aid in the development of antiviral therapeutic strategies for HSV-1-associated diseases.

Accumulation of asoluble form of human nectin-2 is required for exerting the resistance against herpes simplex virus type 2 infection in transfected cells.

Cell entry of herpes simplex virus type 2 (HSV-2) requires the interaction of viral glycoprotein D (gD) with the receptor nectin-1 and herpesvirus entry mediator (HVEM). In addition, it is known that nectin-2 is also functional as areceptor for HSV-2, although the binding to the gD is weak. To examine an antiviral potential of asoluble form of human nectin-2 (hNectin-2Ig), transfected Vero cells expressing the entire ectodomain of nectin-2 fused to the Fc portion of human IgG were established. Specific binding of hNectin-2Ig to HSV-2 gD was confirmed by ELISA. Competitive ELISA demonstrated that accumulation of hNectin-2Ig in transfected cells increased significantly in acell culture time dependent manner. Viral growth of several HSV-2 strains was significantly inhibited in the transfected cells that were cultured for 72 hr compared with control Vero cells, but not in cells that were cultured for 24 hr. These results indicate that accumulation of asoluble form of nectin-2 is required for exerting the resistance against HSV-2 infection.

Induction of interferon-λ contributes to TLR3 and RIG-I activation-mediated inhibition of herpes simplex virus type 2 replication in human cervical epithelial cells.

Is it possible to immunologically activate human cervical epithelial cells to produce antiviral factors that inhibit herpes simplex virus type 2 (HSV-2) replication? Our results indicate that human cervical epithelial cells possess a functional TLR3/RIG-I signaling system, the activation of which can mount an Interferon-λ (IFN-λ)-mediated anti-HSV-2 response. There is limited information about the role of cervical epithelial cells in genital innate immunity against HSV-2 infection. We examined the expression of toll-like receptors (TLRs) and retinoic acid-inducible I (RIG-I) in End1/E6E7 cells by real-time PCR. The IFN-λ induced by TLR3 and RIG-I activation of End1/E6E7 cells was also examined by real-time PCR and ELISA. HSV-2 infection of End1/E6E7 cells was evaluated by the real-time PCR detection of HSV-2 gD expression. The antibody to IL-10Rβ was used to determine whether IFN-λ contributes to TLR3/RIG-I mediated HSV-2 inhibition. Expression of interferon regulatory factor 3 (IRF3), IRF7, IFN-stimulated gene 56 (ISG56), 2'-5'-oligoadenylate synthetase I (OAS-1) and myxovirus resistance A (MxA) were determined by the real-time PCR and western blot. End1/E6E7 cells were transfected with shRNA to knockdown the IRF3, IRF7 or RIG-I expression. Student's t-test and post Newman-Keuls test were used to analyze stabilized differences in the immunological parameters above between TLR3/RIG-I-activated cells and control cells. Human cervical epithelial cells expressed functional TLR3 and RIG-I, which could be activated by poly I:C and 5'ppp double-strand RNAs (5'ppp dsRNA), resulting in the induction of endogenous interferon lambda (IFN-λ). The induced IFN-λ contributed to TLR3/RIG-I-mediated inhibition of HSV-2 replication in human cervical epithelial cells, as an antibody to IL-10Rβ, an IFN-λ receptor subunit, could compromise TLR3/RIG-I-mediated inhibition of HSV-2. Further studies showed that TLR3/RIG-I signaling in the cervical epithelial cells by dsRNA induced the expression of the IFN-stimulated genes (ISGs), ISG56, 2'-5'-oligoadenylate synthetase I (OAS-1) and myxovirus resistance A (MxA), the key antiviral elements in the IFN signaling pathway. In addition, we observed that the topical treatment of genital mucosa with poly I:C could protect mice from genital HSV-2 infection. Future prospective studies with primary cells and suitable animal models are needed in order to confirm these outcomes. The findings provide direct and compelling evidence that there is intracellular expression and regulation of IFN-λ in human cervical epithelial cells, which may have a key role in the innate genital protection against viral infections. Not applicable. This work was supported by the National Natural Science Foundation of China (81301428 to L.Z. and 81271334 to W.-Z.H.), the Fundamental Research Funds for the Central Universities (2042015kf0188 to L.Z.), the China Postdoctoral Science Foundation (2013M531745 to L.Z.), the Development Program of China ('973', 2012CB518900 to W.-Z.H.) from the Ministry of Science and Technology of the People's Republic of China, grants (DA12815 and DA022177 to W.-Z.H.) from the National Institute on Drug Abuse (NIDA) and the open project of Hubei Key Laboratory of Wudang Local Chinese Medicine Research (WDCM005 to M.S.). The authors declare no competing financial interests.

Therapeutic immunization with a mixture of herpes simplex virus type 1 Glycoprotein D derived “asymptomatic” human CD8+ T cell epitopes decreases spontaneous ocular shedding in latently infected HLA transgenic rabbits: association with low frequency of local PD-1+TIM-3+CD8+ exhausted T cells (VAC4P.1114)

Abstract Most blinding ocular herpetic disease is due to reactivation of herpes simplex virus type 1 (HSV-1) from latency rather than to primary acute infection. No herpes simplex vaccine is currently available for use in humans. In this study, we used the HLA-A*02:01 transgenic (HLA Tg) rabbit model of ocular herpes to assess the therapeutic efficacy of a therapeutic vaccine based on HSV-1 gD epitopes that are mainly recognized by CD8+ T cells from “naturally” protected HLA-A*02:01 positive, HSV-1 seropositive healthy asymptomatic (ASYMP) individuals (who have never had clinical herpes disease). Three ASYMP CD8+ T cell epitopes (gD53-61, gD70-78 and gD278-286) were linked with a promiscuous CD4+ T-cell epitope (gD287-317) to create 3 separate pairs of CD4-CD8 peptides, which were then each covalently coupled to an Ne-palmitoyl-lysine moiety, a toll like receptor 2 (TLR-2) ligand. This resulted in the construction of 3 CD4-CD8 lipopeptide vaccines. Latently infected HLA-Tg rabbits were immunized with a mixture of these 3 ASYMP lipopeptide vaccines, delivered as eye drops in sterile PBS. The ASYMP therapeutic vaccination: (i) significantly reduced HSV-1 shedding detected in tears; (ii) boosted the number and function of local HSV-1-specific CD8+ T cells; and (iii) was associated with fewer exhausted HSV-1 gD-specific PD-1+TIM-3+CD8+ T-cells. The results underscore the potential of an ASYMP CD8+ T cell epitope-based therapeutic vaccine strategy against recurrent ocular herpes.

Zebrafish encoded 3-O-sulfotransferase-2 generated heparan sulfate serves as a receptor during HSV-1 entry and spread

Previously we reported the role of zebrafish (ZF) encoded glucosaminyl 3-O-sulfotransferase-3 (3-OST-3) isoform in assisting herpes simplex virus type-1 (HSV-1) entry and spread by generating an entry receptor to HSV-1 envelope glycoprotein D (gD). However, the ability of ZF encoded 3-OST-2 isoform to participate in HSV-1 entry has not been determined although it is predominantly expressed in ZF brain, a prime target for HSV-1 to infect and establish lifelong latency. Here we report the expression cloning of ZF encoded 3-OST-2 isoform and demonstrate HSV-1 entry into resistant Chinese hamster ovary (CHO-K1) cells expressing the clone. Additional significance of ZF encoded 3-OST-2 receptor was demonstrated using medically important isolates of HSV-1. In addition, interference to HSV-1 entry was observed upon co-expression of HSV-1 gD and ZF 3-OST-2. Similarly HSV-1 entry was significantly inhibited by the pre-treatment of cells with enzyme HS lyases (heparinase II/III). Finally, ZF-3-OST-2 expressing CHO-K1 was able to fuse with HSV-1 glycoprotein expressing cells suggesting their role in HSV-1 spread. Taken together our result demonstrates a role for ZF 3-OST-2 in HSV-1 pathogenesis.

Nasal and skin delivery of IC31®-adjuvanted recombinant HSV-2 gD protein confers protection against genital herpes

Genital herpes caused by herpes simplex virus type 2 (HSV-2) remains the leading cause of genital ulcers worldwide. Given the disappointing results of the recent genital herpes vaccine trials in humans, development of novel vaccine strategies capable of eliciting protective mucosal and systemic immune responses to HSV-2 is urgently required. Here we tested the ability of the adjuvant IC31® in combination with HSV-2 glycoprotein D (gD) used through intranasal (i.n.), intradermal (i.d.), or subcutaneous (s.c.) immunization routes for induction of protective immunity against genital herpes infection in C57BL/6 mice. Immunization with gD plus IC31® through all three routes of immunization developed elevated gD-specific serum antibody responses with HSV-2 neutralizing activity. Whereas the skin routes promoted the induction of a mixed IgG2c/IgG1 isotype profile, the i.n. route only elicited IgG1 antibodies. All immunization routes were able to induce gD-specific IgG antibody responses in the vaginas of mice immunized with IC31®-adjuvanted gD. Although specific lymphoproliferative responses were observed in splenocytes from mice of most groups vaccinated with IC31®-adjuvanted gD, only i.d. immunization resulted in a significant splenic IFN-γ response. Further, immunization with gD plus IC31® conferred 80–100% protection against an otherwise lethal vaginal HSV-2 challenge with amelioration of viral replication and disease severity in the vagina. These results warrant further exploration of IC31® for induction of protective immunity against genital herpes and other sexually transmitted infections.

Cloning and phylogenetic analysis of gD gene of human herpes simplex virus type 2 in Iranian isolates

Herpes simplex virus type 2 (HSV-2) is a member of herpesviridae family and subfamily of alphaherpesvirinae. HSV-2 infection often causes genital herpes in women and men, abortion, infant herpes and non-infectious meningitides. Glycoprotein D and B respectively, are coded by gD and gB gene. They are the adhesion of HSV-2 attached to the surface of the epithelial cells and are used for making vaccine. To determine the phylogenetic analysis of HSV-2 gD gene and cloning of it in E. coli, infected samples from Esfahan and Chaharmahal Va Bakhtiari provinces in Iran, which were multiplied by PCR and then the segments having 1013bp lengths related to 3 infected samples for gD gene were selected in cloning pCR 4-TOPO plasmid and sequencing. After determining the nucleotide sequences of HSV-2 gD gene, they were compared with samples reported in Iran and other countries. The results showed 2.8 - 10% genetic differentiation which enjoyed more affinity with nucleotide sequenced in USA (K02373) with 97.2% and the biggest difference is in Sweden sample (EU018093) with 90%. The current research showed high homology in the sequence of gD gene of HSV-2. Then, with presence of these affinities in the research samples and other species of Iran and other countries, a good vaccine can be made with high efficiency against all HSV-2 species in the world. Key words: Herpes simplex virus type 2 (HSV-2), PCR, gD gene, phylogenenetic analysis, Iran, Chaharmahal Va Bakhtiari province, Esfahan province.

Interaction of herpes simplex virus type 2 (HSV-2) glycoprotein D with the host cell surface is sufficient to induce Chlamydia trachomatis persistence

When presented with certain unfavourable environmental conditions, Chlamydia trachomatis reticulate bodies (RBs) enter into a viable, yet non-cultivable state called persistence. Previously, we established an in vitro C. trachomatis and herpes simplex virus type 2 (HSV-2) co-infection model. These data indicate that (i) viral co-infection stimulates chlamydial persistence, (ii) productive HSV replication is not required for persistence induction, and (iii) HSV-induced persistence is not mediated by any currently characterized anti-chlamydial pathway or persistence inducer. In this study we demonstrated that chlamydial infectivity, though initially suppressed, recovered within 44 h of co-infection with UV-inactivated HSV-2, demonstrating that HSV-induced persistence is reversible. Co-incubation of chemically fixed, HSV-2-infected inducer cells with viable, C. trachomatis-infected responder cells both suppressed production of infectious chlamydial progeny and stimulated formation of swollen, aberrantly shaped RBs. In addition, pre-incubation of viral particles with viral glycoprotein D (gD)-specific neutralizing antibody prevented co-infection-induced persistence. Finally, exposure of C. trachomatis-infected cells to a soluble, recombinant HSV-2 gD : Fc fusion protein decreased production of infectious EBs to a degree similar to that observed in co-infected cultures. Thus, we conclude that interaction of HSV gD with the host cell surface is sufficient to trigger a novel host anti-chlamydial response that restricts chlamydial development.

Liposomal gD ectodomain (gD 1–306) vaccine protects against HSV2 genital or rectal infection of female and male mice

Herpes simplex virus type 2 (HSV2) is the most common causative agent of genital herpes, with infection rates as high as 1 in 6 adults. The present studies were done to evaluate the efficacy of a liposomal HSV2 gD 1–306 vaccine (L-gD 1–306-HD) in an acute murine HSV2 infection model of intravaginal (female) or intrarectal (male or female) challenge. Two doses of L-gD 1–306-HD containing 60 μg gD 1–306-HD and 15 μg monophosphoryl lipid A (MPL) per dose provided protection against HSV2 intravaginal challenge (86–100% survival, P ≤ 0.0003 vs. control liposomes; P = 0.06 vs. L-gD 1–306-HD without MPL). Both male and female mice (BALB/c and C57BL/6) immunized with L-gD 1–306-HD/MPL were significantly protected against HSV2 intrarectal challenge, with higher survival rates compared to controls (71–100%, P ≤ 0.007). L-gD 1–306-HD/MPL also provided increased survival when compared to a liposomal peptide vaccine, L-gD 264–285-HD/MPL (male BALB/c, P ≤ 0.001; female BALB/c and male C57BL/6, P = 0.06). Mice given L-gD 1–306-HD/MPL also had minimal disease signs, reduced viral burden in their spinal cords and elevated neutralizing antibody titers in the females. The vaccine also stimulated gD 1–306-HD specific splenocytes of both male and female mice with significantly elevated levels of IFN-γ compared to IL-4 ( P ≤ 0.01) indicating that there was an enhanced Th1 response. These results provide the first evidence that the L-gD 1–306-HD vaccine can protect both male and female mice against intrarectal HSV2 challenge.

A sugar binding protein cyanovirin-N blocks herpes simplex virus type-1 entry and cell fusion

Herpes simplex virus type-1 (HSV-1) causes significant health problems from periodic skin and corneal lesions to encephalitis. It is also considered a cofactor in the development of age-related secondary glaucoma. Inhibition of HSV-1 at the stage of viral entry generates a unique opportunity for preventative and/or therapeutic intervention. Here we provide evidence that a sugar binding antiviral protein, cyanovirin-N (CV-N), can act as a potent inhibitor of HSV-1 entry into natural target cells. Inhibition of entry was independent of HSV-1 gD receptor usage and it was observed in transformed as well as primary cell cultures. Evidence presented herein suggests that CV-N can not only block virus entry to cells but also, it is capable of significantly inhibiting membrane fusion mediated by HSV glycoproteins. While CV-N treated virions were significantly deficient in entering into cells, HSV-1 glycoproteins-expressing cells pretreated with CV-N demonstrated reduced cell-to-cell fusion and polykaryocytes formation. The observation that CV-N can block both entry as well as membrane fusion suggests a stronger potential for this compound in antiviral therapy against HSV-1.

The importance of heparan sulfate in herpesvirus infection

Herpes simplex virus type-1 (HSV-1) is one of many pathogens that use the cell surface glycosaminoglycan heparan sulfate as a receptor. Heparan sulfate is highly expressed on the surface and extracellular matrix of virtually all cell types making it an ideal receptor. Heparan sulfate interacts with HSV-1 envelope glycoproteins gB and gC during the initial attachment step during HSV-1 entry. In addition, a modified form of heparan sulfate, known as 3-O-sulfated heparan sulfate, interacts with HSV-1 gD to induce fusion between the viral envelope and host cell membrane. The 3-O-sulfation of heparan sulfate is a rare modification which occurs during the biosynthesis of heparan sulfate that is carried out by a family of enzymes known as 3-O-sulfotransferases. Due to its involvement in multiple steps of the infection process, heparan sulfate has been a prime target for the development of agents to inhibit HSV entry. Understanding how heparan sulfate functions during HSV-1 infection may not only be critical for inhibiting infection by this virus, but it may also be crucial in the fight against many other pathogens as well.