KOS Strain Of Herpes Simplex Virus Type 1 Research Articles

Adenovirus-mediated RNA interference against herpes simplex virus infection in vitro.

Herpetic keratitis caused by the herpes simplex virus (HSV) is the most common form of ocular herpes that causes corneal blindness. Although treatments for herpes keratitis have improved in recent years. there is still considerable room for new treatments against viral infection that shows great promise. The aim of the study was to evaluate the effect of RNA interference on HSV Type 1 (HSV1) infection in vitro, first prophylactically then therapeutically. The highly conserved glycoproteins D (gD) and E (gE) were chosen as targets for this study. Different small interfering RNA (siRNA) duplexes that target gD and gE were designed and chemically synthesized. The recombinant adenovirus type 5 was developed and used as the vehicle with which we delivered the siRNA into the Vero cells infected with the HSV1 KOS strain. Evaluation of the efficacy of siRNA-mediated inhibition was performed either before virus inoculation (prophylactically) or after virus inoculation at the first appearance of lesions (therapeutically). The expression of messenger RNA encoding gD and gE was detected using a real-time polymerase chain reaction (qPCR). We analyzed HSV replication in Vero cells, cytotoxicity of HSV, and cell viability. When used prophylactically, the siRNA-targeting gD and gE created a more marked decrease in viral titer than when used therapeutically. The transfection of cells with recombinant adenovirus containing the siRNA expression cassette was associated with very low cytotoxicity. Adenovirus-mediated siRNA-targeting gD and gE genes effectively inhibit the replication of the HSV in Vero cells. In addition, these findings indicate that the prophylactic use of siRNA is far more effective at inhibiting HSV replication than the therapeutic use.

Short term exercise training enhances cell-mediated responses to HSV-1 vaccine in mice.

Exercise (with appropriate intensity and duration) is a natural modulator of immune responses and may be useful to increase the vaccine response towards antigen. According to the fact that rural area responding butter than urbon area to vaccine protocol, this study was undertaken to test the hypothesis that short term exercise training as an adjuvant for antigen such as herpes simplex virus type 1 (HSV-1) in animal models. Mice with/without access to short term exercise training were immunized intramuscularly with inactivated KOS strain of HSV-1. Immune responses was investigated with regards of both cell-mediated and humoral immunity. In this study by using short term exercise training as an adjuvant enhanced Th1 response while it did not show significant effect on Th2 responses towards HSV-1 immunization. Also, immunoglobulin G (IgG) 2a/IgG1-ratios increased in vaccine with short term exercise training group. These results suggested that coupling short term moderate exercise training as a mild adjuvant with vaccination may enhance cell-mediated immune responses especially Th1 responses.

Facial paralysis induced by ear inoculation of herpes simplex virus in rat.

Bell's palsy is caused by the reactivation of herpes simplex virus type 1 (HSV-1). Using Balb/c mice inoculated with the KOS strain of HSV-1, we previously developed an animal disease model that simulated mild Bell's palsy. The current study developed an animal disease model of more severe facial palsy than that seen in the mouse model. Three-week-old female Wister rats weighing 60-80g were inoculated on the auricle with HSV-1 and acyclovir was administered intraperitoneally to deactivate the infected HSV-1. Instead of HSV-1, phosphate-buffered saline was used for inoculation as a negative control. Quantitative polymerase chain reaction (PCR), behavior testing (blink reflex), electroneuronography, histopathology of the peripheral nerve, and immunohistochemistry of the facial nerve nucleus were evaluated. Facial palsy occurred 3-5 days after virus inoculation, and the severity of the facial palsy progressed for up to 7 days. Quantitative PCR showed an increase in HSV-1 DNA copies in the facial nerve from 24 to 72h, suggesting that HSV-1 infection occurred in the nerve. Electroneuronography values were 33.0±15.3% and 110.0±18.0% in HSV-1-inoculated and control rats, respectively. The histopathology of the peripheral nerve showed demyelination and loss of the facial nerve, and the facial nerve nucleus showed degeneration. Facial palsy developed in Wister rats following inoculation of the KOS strain of HSV-1 onto the auricles. The behavioral, histopathological, and electroneuronography data suggested that the severity of facial palsy was greater in our rats than in animals in the previous mouse disease model.

Biological Features of Herpes Simplex Virus Type 1 Latency in Mice According to Experimental Conditions and Type of Neurones

To compare the biological patterns of viral transcripts during herpes simplex virus type 1 (HSV1) latent infection according to experimental conditions. Two types of murine models of HSV1 infection were used: the corneal scarification model, often used in studies of HSV1 latency, and the oro-ocular murine model. Two strains of HSV1 were used for the inoculation: SC16, a wild type strain considered as highly neuroinvasive, and KOS, previously described as poorly neurovirulent. The amounts of viral genomes, and those of four types of viral transcripts (immediate-early, early and late, together with latency-associated transcripts [LATs]), were measured by quantitative PCR and RT-PCR in the main sites of HSV1 latent infection at 6 days, 1 and 3 months post inoculation, and the number of LAT-expressing neurons was assessed by in-situ hybridization on histological sections of trigeminal ganglia (TG). Using the SC16 strain of HSV1 in the oro-ocular model, immediate-early transcripts were still present at 1 month post inoculation (early stage of latent infection), but were not detected at 3 months (late stage of latent infection). In both cases, early and late viral genes transcripts were not detected, demonstrating the latent nature of the infection with this combination of experimental conditions. In contrast, such progress in the viral gene expression was not observed in the corneal scarification model, particularly when the KOS strain of HSV1 was used. These results highlight that the behavior of the virus in the nervous system depends on the method inoculation, and the viral strain. All these parameters are likely to influence the establishment of latent infection.

Expression of interleukin-9 in murine cornea with herpetic stromal keratitis

Background Herpetic stromal keratitis (HSK) is an immunopathologic eye disorder mediated by CD4+ T lymphocytes.Interleukin-9 (IL-9) is a cytokine linked to the process of many immune inflammatory diseases,but whether IL-9 is involved in the immunopathology of HSK remains unclear.Objective This study was to investigate the expression of IL-9 in murine cornea during the development of HSK and its relationship with the degree of HSK.Methods One hundred and eighty clean BALB/c mice were divided into the normal control group (20 mice) and experimental group (160 mice).HSK models were established by scratching on the surface of the cornea followed by inoculation of 1 × 106 plague forming unit(PFU) herpes simplex virus type 1 (HSV-1) KOS strain.Change of ocular surface was examined under the slit lamp biomicroscopy before and I day,3,5,7,8,10,14,21 days after inoculation of HSV-1.The corneas of mice were collected on the time points mentioned above.The relative expression level of IL-9 mRNA in the cornea of mice was detected by real-time PCR.Immunocytochemical localization of IL-9 protein in murine cornea was viewed by a confocal microscope after preparation of the corneal cryostat sections.All experimental manipulations were undertaken in accordance with the institutional guidelines for the care and use of laboratory animals.Results Punctiform,dendriform or geographic defect in corneal epithelium were seen 3 days and healing 6 days after inoculation of HSV-1.However,edema and opacity of the corneal stroma appeared 7 days and peaked 14 days following the inoculation.Real-time PCR assay showed that very little of IL-9 mRNA (A260/A280) was expressed in the cornea in the mice of the control group.But in 1 day,3,5,7,8,10 and 14 days,the relative level of IL-9 mRNA was 6.37±0.45,5.66±0.53,3.93±0.35,3.62±0.34,3.23±0.18,2.57±0.14,2.19±0.20,with a significant difference among the various time points (F=92.764,P=0.000),and IL-9 mRNA in 1 day,3,5,7,8,10 and 14 days after inoculation was significantly higher than before inoculation (P＜0.05);while no markedly difference was found in IL-9 mRNA expression between the 21-day group after inoculation and the normal control group (P =0.340).IL-9 protein was expressed in the epithelial layer,stromal layer and endothelial cell layer of the corneas,with a stronger green fluorescence in the HSK mice,but no expression of IL-9 protein was seen in the control mice.Conclusions HSK model can be successfully created by corneal scratching and inoculation of HSV-1 KOS strain in BALB/c mouse.IL-9 is involved in the pathogenesis and development of HSK mediated by immunoresponse. Key words: Herpes simplex virus type 1 ; Cornea; Interleukin-9 ; Stromal keratitis

Antiviral activities of aerial subsets of Artemisia species against Herpes Simplex virus type 1 (HSV1) in vitro

Abstract Background: Drug resistance to current anti-herpetic drugs has been increasingly reported. Therefore, there is a need for finding new antiviral agents, in particular from natural sources. Objective: In the present study, antiviral activity of subset extracts obtained from aerial parts of Artemisia including A. incana, A. chamaemelifolia, A. campesteris, A. fragrans, A. annua, A. vulgaris, and A. persica were investigated against Herpes Simplex type I (HSV1). Methods: Different concentrations of extracts (400, 200, 100, 50, 25, 12.5, 6.25, and 3.125 μg/mL) were obtained from subset of each plant separately, and used against KOS strain of HSV1 in HeLa cells. After 24 hours incubation, tetrazolium dye (MTT), was added. The dye absorption by viable cells was measured and compared to the positive control (extract-untreated cells) and acyclovir (as anti-viral agent). Results: The extracts obtained from A. annua had the highest antiviral activity while those of A. chamaemelifolia showed the lowest activity. Conclusion: Subset extracts of A. annua may be an appropriate candidate for further development of anti HSV1 infection.

Phenoxazine Derivatives Suppress the Infections Caused by Herpes Simplex Virus Type-1 and Herpes Simplex Virus Type-2 Intravaginally Inoculated Into Mice

We examined the in vivo antiviral activities of 2-amino-4,4α-dihydro-4α-7-dimethyl-3H-phenoxazine-3-one (Phx-1), 3-amino-1,4α-dihydro-4α-8-dimethyl-2H-phenoxazine-2-one (Phx-2), and 2-aminophenoxazine-3-one (Phx-3) against herpes viruses. The virus yield three days after administration, changes in the 6-degree’s lesion scores, and the morbidity were assessed after herpes simplex virus type-1 (HSV-1) [acyclovir (ACV)-sensitive KOS strain or ACV-resistant A4-3 strain] or HSV-2 (ACV-sensitive UW 268 strain) was inoculated intravaginally to mice with administration of Phx-1, Phx-2, Phx-3, or ACV (0.2 mg per administration, 3 times daily) for 8 days starting from 1 day before virus inoculation to 7 days after infection. Phx-1, Phx-2, and Phx-3 extensively suppressed the virus yield of HSV-1. Only Phx-2 exerted moderate inhibitory effects against HSV-2 in mice. The lesion scores, as clinical signs manifested by infection of the KOS strain of HSV-1, were extensively suppressed by intravaginal application of Phx-1, Phx-2, or Phx-3. The lesion scores in HSV-2–infected mice indicated moderate suppression, when Phx-1, Phx-2, or Phx-3 was applied. Without treatment by one of the compounds, none of the HSV-1– infected mice died, but all the HSV-2–infected ones did. However, by the administration of Phx-1, Phx-2, or Phx-3 fairly improved the survival rates of the HSV-2–infected mice. Phx-2 showed dose-dependent anti-HSV-2 efficacy when administered at doses of 0.2 and 1 mg per administration. The present in vivo data suggest that the Phx-1, Phx-2, and Phx-3 are attractive candidates for agents to prevent both replication of HSV and aggravation of lesions caused by these viruses.

A novel adjuvant, the general opioid antagonist naloxone, elicits a robust cellular immune response for a DNA vaccine

While many adjuvants have been discovered and used in research, only a few adjuvants have been permitted for use with human vaccination. We have previously shown that the administration of naloxone (NLX), a general opioid antagonist, during infection with a non-virulent strain of herpes simplex virus type 1 (HSV-1) could enhance protection against HSV-1 challenge. Here, the adjuvant activity of NLX has been evaluated using a DNA vaccine for HSV-1 as a model. BALB/c mice were divided into four groups; for experimental groups, mice received the glycoprotein D1 (gD1) DNA vaccine alone or in combination with the adjuvant NLX. A positive control group received the KOS strain of HSV-1, and a negative control group received PBS. All mice were immunized three times on days 0, 21 and 42. Three weeks after the last immunization, immune responses against HSV-1 were assessed. Our results indicate that the administration of NLX as an adjuvant increased the ability of the gD1 DNA vaccine to enhance cytolytic T lymphocyte activity, lymphocyte proliferation, delayed-type hypersensitivity and shifting the immune response toward a T helper (Th)1 pattern and improved protective immunity against HSV-1. NLX also increased the IgG2a/IgG1 ratio, though it did not affect the production of HSV-1 antiserum. In conclusion, administration of NLX as an adjuvant in combination with the gD1 DNA vaccine can enhance cell-mediated immunity and shift the immune responses to Th1.

English

The hot water extract of a brown marine alga, Cystoseira myrica, from the Persian Gulf was evaluated as an antiviral compound against KOS strain of HSV-1 in cell culture. The extract exhibited antiviral activity against herpes simplex virus type 1 (HSV-1) not only during absorption of virus to the cells, but also on post attachment stages of virus replication. The water extract of C. myrica was sterilized by filtration and autoclaving, respectively. The IC50 for filtered extract was 99 µg/ml and the IC50 for autoclaved extract was 125 µg/ml. Based on resulted selectivity index (SI) values of the extracts, which were 33.4 and 28.2 for filtered and autoclaved extracts, respectively, we found that the antiviral compound(s) in the water extract of C. myrica to be heat stable. Also, the SI values for inhibition of the post attachment stages of HSV-1 replication were 23.1 and 21.7 for filtered and autoclaved extracts, respectively. The IC50 in this phase of study were 143 and 162 µg/ml for filtered and autoclaved extracts, respectively. Therefore, C. myrica could be a good candidate as a natural source for anti-HSV-1 compound(s) isolation.   Key words: Cystoseira myrica, HSV-1, antiviral, Persian Gulf.

The herpes simplex virus type 1 UL20 protein modulates membrane fusion events during cytoplasmic virion morphogenesis and virus-induced cell fusion.

The herpes simplex virus type 1 (HSV-1) UL20 protein is an important determinant for virion morphogenesis and virus-induced cell fusion. A precise deletion of the UL20 gene in the HSV-1 KOS strain was constructed without affecting the adjacent UL20.5 gene. The resultant KOS/UL20-null virus produced small plaques of 8 to 15 cells in Vero cells while it produced wild-type plaques on the complementing cell line G5. Electron microscopic examination of infected cells revealed that the KOS/UL20-null virions predominantly accumulated capsids in the cytoplasm while a small percentage of virions were found as enveloped virions within cytoplasmic vacuoles. Recently, it was shown that UL20 expression was necessary and sufficient for cell surface expression of gK (T. P. Foster, X. Alvarez, and K. G. Kousoulas, J. Virol. 77:499-510, 2003). Therefore, we investigated the effect of UL20 on virus-induced cell fusion caused by syncytial mutations in gB and gK by constructing recombinant viruses containing the gBsyn3 or gKsyn1 mutations in a UL20-null genetic background. Both recombinant viruses failed to cause virus-induced cell fusion in Vero cells while they readily caused fusion of UL20-null complementing G5 cells. Ultrastructural examination of UL20-null viruses carrying the gBsyn3 or gKsyn1 mutation revealed a similar distribution of virions as the KOS/UL20-null virus. However, cytoplasmic vacuoles contained aberrant virions having multiple capsids within a single envelope. These multicapsid virions may have been formed either by fusion of viral envelopes or by the concurrent reenvelopment of multiple capsids. These results suggest that the UL20 protein regulates membrane fusion phenomena involved in virion morphogenesis and virus-induced cell fusion.

The first immunoglobulin-like domain of HveC is sufficient to bind herpes simplex virus gD with full affinity, while the third domain is involved in oligomerization of HveC.

The human herpesvirus entry mediator C (HveC/PRR1) is a member of the immunoglobulin family used as a cellular receptor by the alphaherpesviruses herpes simplex virus (HSV), pseudorabies virus, and bovine herpesvirus type 1. We previously demonstrated direct binding of the purified HveC ectodomain to purified HSV type 1 (HSV-1) and HSV-2 glycoprotein D (gD). Here, using a baculovirus expression system, we constructed and purified truncated forms of the receptor containing one [HveC(143t)], two [HveC(245t)], or all three immunoglobulin-like domains [HveC(346t)] of the extracellular region. All three constructs were equally able to compete with HveC(346t) for gD binding. The variable domain bound to virions and blocked HSV infection as well as HveC(346t). Thus, all of the binding to the receptor occurs within the first immunoglobulin-like domain, or V-domain, of HveC. These data confirm and extend those of Cocchi et al. (F. Cocchi, M. Lopez, L. Menotti, M. Aoubala, P. Dubreuil, and G. Campadelli-Fiume, Proc. Natl. Acad. Sci. USA 95:15700, 1998). Using biosensor analysis, we measured the affinity of binding of gD from HSV strains KOS and rid1 to two forms of HveC. Soluble gDs from the KOS strain of HSV-1 had the same affinity for HveC(346t) and HveC(143t). The mutant gD(rid1t) had an increased affinity for HveC(346t) and HveC(143t) due to a faster rate of complex formation. Interestingly, we found that HveC(346t) was a tetramer in solution, whereas HveC(143t) and HveC(245t) formed dimers, suggesting a role for the third immunoglobulin-like domain of HveC in oligomerization. In addition, the stoichiometry between gD and HveC appeared to be influenced by the level of HveC oligomerization.

Specific binding of herpes simplex virus type 1 (HSV-1) strain HSZP to host cell surface can provoke interference with early shutoff of host protein synthesis induced by HSV-1 strain KOS

The HSZP strain of herpes simplex virus type 1 (HSV-1) is defective with respect to the early shutoff of host protein synthesis but is effective at interfering with the early shutoff function of the HSV-1 KOS strain, even when heat-inactivated or neutralized by antibody. The interference was not due to exclusion of strain KOS by HSZP at the level of adsorption or penetration. The component responsible for the interference is an integral part of HSZP virions. Strain HSZP inactivated with zinc ions failed to interfere with the early shutoff function of the superinfecting strain KOS. The same effect was also found with strain HSZP purified from cells treated with 2-deoxy-D-glucose. This finding supports the idea that a specific interaction between HSZP virions and the cell surface can be responsible for the interference phenomenon.

Molecular characterization of naturally occurring glycoprotein C-negative herpes simplex virus type 1.

We previously isolated glycoprotein C (gC)-negative herpes simplex virus type 1 (HSV-1) mutants, TN-1, TN-2 and TN-3, from a patient with recurrent herpetic keratitis at one-year intervals. In the present study, the molecular basis for the inability of these clinical isolates to express gC was examined. The nucleotide sequence of the gC gene of the TN-1 strain was compared with that of the HSV-1 KOS strain. In the open reading frame of the gC gene, there were 12 nucleotide differences between the TN-1 and KOS strains, seven of which led to amino acid substitutions. Importantly, one of them was the codon change from CAG for glutamine at position 280 to TAG for the amber termination codon. Accordingly, the TN-1 strain produced a truncated gC with a predicted molecular weight, which was secreted into the extracellular fluid. These results suggest that this amber mutation in the TN-gC gene results in a premature termination of gC translation and is the cause of the gC-negative phenotype of the TN strains. It is expected that these extremely rare HSV-1 strains will provide us with valuable information concerning the in vivo functions of gC, especially in ocular diseases.

Herpes simplex virus type 1 (HSV-1) HSZP interferes also after antibody neutralization with early shutoff of host protein synthesis induced by HSV-1 KOS.

The HSZP strain of herpes simplex virus type 1 (HSV-1) is defective with respect to the early shutoff of host protein synthesis. However, in superinfection experiments using Vero cells, the HSZP strain was effective, even after neutralization by antibody, at interfering with the early shutoff function of the HSV-1 KOS strain. Evidence was given that the observed interference was not due to exclusion of the KOS by HSZP at the level of adsorption or penetration. The neutralized KOS strain failed to induce early shutoff of host protein synthesis.

Oncogenic transformation of hamster embryo cells after exposure to inactivated herpes simplex virus type 1.

The in vitro transformation of hamster embryo fibroblasts by herpes simplex virus type 1 (HSV-1) after exposure of the virus to UV irradiation is described. Cell transformation was induced by 2 out of 12 strains of HSV-1 that were tested for transforming potential. Cells transformed by the KOS strain of HSV-1 were not oncogenic when injected into newborn Syrian hamsters. However, cells transformed by HSV-1 strain 14-012 induced tumors in 47% of the newborn hamsters injected. HSV-specific antigens were found in the cytoplasm of cells transformed by both virus strains. Sera from tumor-bearing hamsters contained HSV-1- and HSV-2-neutralizing antibodies as well as antibodies which reacted specifically with HSV antigens by the indirect immunofluorescence technique. Hamster oncornavirus antigens were not detected by immunofluorescence methods. These observations represent the first evidence of the oncogenic potential of HSV-1.