Characteristics of herpes simplex virus infection and pathogenesis suggest a strategy for vaccine development

Herpes simplex virus (HSV) can cause oral or genital ulcerative lesions and even encephalitis in various age groups with high infection rates. More seriously, HSV may lead to a wide range of recurrent diseases throughout a lifetime. No vaccines against HSV are currently available. The accumulated clinical research data for HSV vaccines reveal that the effects of HSV interacting with the host, especially the host immune system, may be important for the development of HSV vaccines. HSV vaccine development remains a major challenge. Thus, we focus on the research data regarding the interactions of HSV and host immune cells, including dendritic cells (DCs), innate lymphoid cells (ILCs), macrophages, and natural killer (NK) cells, and the related signal transduction pathways involved in immune evasion and cytokine production. The aim is to explore possible strategies to develop new effective HSV vaccines.

Evidence for DNA-mediated nuclear compartmentalization distinct from phase separation

RNA Polymerase II (Pol II) and transcription factors form concentrated hubs in cells via multivalent protein-protein interactions, often mediated by proteins with intrinsically disordered regions. During Herpes Simplex Virus infection, viral replication compartments (RCs) efficiently enrich host Pol II into membraneless domains, reminiscent of liquid-liquid phase separation. Despite sharing several properties with phase-separated condensates, we show that RCs operate via a distinct mechanism wherein unrestricted nonspecific protein-DNA interactions efficiently outcompete host chromatin, profoundly influencing the way DNA-binding proteins explore RCs. We find that the viral genome remains largely nucleosome-free, and this increase in accessibility allows Pol II and other DNA-binding proteins to repeatedly visit nearby DNA binding sites. This anisotropic behavior creates local accumulations of protein factors despite their unrestricted diffusion across RC boundaries. Our results reveal underappreciated consequences of nonspecific DNA binding in shaping gene activity, and suggest additional roles for chromatin in modulating nuclear function and organization.

Comparative in Vitro Titrations of Herpes Simplex Virus in Cells Derived from Normal Uterine Cervix and from Cervical Cancer

Sero-epidemiologic investigations showed a significant association between carcinoma of the cervix uteri and previous infections of the female genital tract with subtype 2, or genital, Herpes Simplex Virus (HSV-2) (ref. 3, 13, 14, 16). This association could be due to a carcinogenic, or co-carcinogenic effect of HSV (ref. 6 and 17), or else to a preferential viral growth in tumoral or transformed cells as against normal cells. To test the latter hypothesis we cultured in vitro cells from normal cervix and from cervical cancer, and assayed HSV-2 (and also HSV-1, or facial, and the MP mutant of HSV-1: ref. 9, 12) in our cell cultures as well as in the human HEp-2 cell line. Equivalent viral yields (results not reported in detail), equivalent numbers of viral plaques (table 1) and similar plaque morphology (fig.8) and intracellular ecp (fig.7) were observed in our cell cultures and in HEp-2 cells. Thus, a preferential viral growth in tumoral cells is not apparent.

Antiviral activity and metal ion-binding properties of some 2-hydroxy-3-methoxyphenyl acylhydrazones

Here we report on the results obtained from an antiviral screening, including herpes simplex virus, vaccinia virus, vesicular stomatitis virus, Coxsackie B4 virus or respiratory syncytial virus, parainfluenza-3 virus, reovirus-1 and Punta Toro virus, of three 2-hydroxy-3-methoxyphenyl acylhydrazone compounds in three cell lines (i.e. human embryonic lung fibroblast cells, human cervix carcinoma cells, and African Green monkey kidney cells). Interesting antiviral EC₅₀ values are obtained against herpes simplex virus-1 and vaccinia virus. The biological activity of acylhydrazones is often attributed to their metal coordinating abilities, so potentiometric and microcalorimetric studies are here discussed to unravel the behavior of the three 2-hydroxy-3-methoxyphenyl compounds in solution. It is worth of note that the acylhydrazone with the higher affinity for Cu(II) ions shows the best antiviral activity against herpes simplex and vaccinia virus (EC₅₀ ~ 1.5 µM, minimal cytotoxic concentration = 60 µM, selectivity index = 40).

Impact of chronic blood viral infection on lymphocyte telomere length in Chornobyl clean-up workers in a remote period after radiation exposure

OBJECTIVE

To assess whether telomere length in lymphocytes of Chornobyl clean up workers at a late period 30 years after the exposure to ionizing radiation is influenced by a chronic blood viral infection and to determine role of viral carriage in cellular senescence.

PATIENTS AND METHODS

Study group included 70 Chornobyl cleanup male workers 30 years after exposure {doses of external exposure (602.67 ± 114.19) mSv (M ± m); age (59.75 ± 0.82) yrs}. Relative telomere length (RTL) was analysed by fluorescence in situ hybridization and flow cytometry, immune cell subsets by standard combinations of monoclonal antibodies (CD45/14, CD3/19, CD4/8, CD3/HLADR, CD3/16/56, TCRγδ) and flow cytometry; antiviral immunity was performed determining the chronic phase antibodies to viruses: Hepatitis C (HCV), Cytomegalovirus (CMV), Toxoplasma gondii (TOX), Herpes simplex (HSV) and Epstein Barr virus (EBV VCA IgG and EBV NA IgG). The object of the study was peripheral blood (PB) of clean up workers.

RESULTS

RTL changes were associated at the group level with the carrier state of the viral infection. RTL shortening was demonstrated as a significant difference between the groups (M ± SD) (HCV negative 15.27 ± 3.35, HCV posi tive 13.09 ± 3.05, p < 0.08, n = 12/52) or as a tendency (CMV negative 15.99 ± 5.41, CMV positive 14.86 ± 3.46 (M ± SD), p < 0.57, n = 11/53; HSV negative 17.01 ± 1.35, HSV positive 14.79 ± 3.80, p < 0.33, n = 13/51; TOX neg ative 15.94 ± 3.41, TOX positive 14.30 ± 3.81(M ± SD), p < 0.23, n = 27/37). These unidirectional changes can be associated with premature early cell aging of immune cells. To the contrary the significant RTL elongation was demonstrated in the group of EBV NA chronic carriers (EBV NA negative 11.25 ± 3.02 (M ± SD), EBV NA positive 16.15 ± 3.08 (M ± SD), p < 0.001, n = 15/49).

CONCLUSION

The study confirmed the assumption on a relationship existing between the telomere length, chronic viral infection and late effects in immune cells. The changes of telomeres length on the background of immune dys function may be a sign of cellular aging, and concomitant chronic blood viral infection such as Hepatitis C, Epstein Barr viruses carriage could form a background for an error prone DNA reparation system as a factor of accumulation of pathological conditions, including malignant transformation.

Myastenia and small doses of ionizing radiation: experience of successful use of rituximab for treatment of an irradiated with myasthenia gravis

A clinical case of the rituximab («Rituksim», «Mabthera») use to treat a man affected by the Chornobyl NPP acci dent with malignant resistant form of myasthenia gravis in conjunction with chronic mixed infection by Toxoplasma, Epstein Barr virus, Cytomegalovirus and Herpes simplex virus is described. In the dynamics of two year's observa tion the clinical efficacy of monoclonal antibodies was shown as the main symptoms stabilization and reducing doses of glucocorticoid and anticholinergic therapy. The positive effect was marked in the nearest and remote peri ods. Taking to account the efficacy, safety and good tolerability of rituximab, it is advisable to recommend treat ment for people exposed to ionizing radiation and developing myasthenia associated with chronic mixed infection by Toxoplasma, Epstein Barr, Cytomegalovirus and Herpes simplex virus.

SiO₂ nanoparticles as platform for delivery of 3'-triazole analogues of AZT-triphosphate into cells

A system for delivery of analogues of AZT-triphosphates (AZT*TP) based on SiO₂ nanoparticles was proposed. For this purpose, a simple and versatile method was developed for the preparation of SiO₂∼dNTP conjugates using the 'click'-reaction between AZTTP and premodified nanoparticles containing the alkyne groups. The substrate properties of SiO₂∼AZT*TP were tested using Klenow fragment and HIV reverse transcriptase. The 3'-triazole derivatives of thymidine triphosphate being a part of the SiO₂∼AZT*TP nanocomposites were shown to be incorporated into the growing DNA chain. It was shown by confocal microscopy that the proposed SiO₂∼AZT*TP nanocomposites penetrate into cells. These nanocomposites were shown to inhibit the reproduction of POX and Herpes viruses at nontoxic concentrations.

Engineering herpes simplex viruses by infection-transfection methods including recombination site targeting by CRISPR/Cas9 nucleases

Herpes simplex viruses (HSVs) are frequent human pathogens and the ability to engineer these viruses underpins much research into their biology and pathogenesis. Often the ultimate aim is to produce a virus that has the desired phenotypic change and no additional alterations in characteristics. This requires methods that minimally disrupt the genome and, for insertions of foreign DNA, sites must be found that can be engineered without disrupting HSV gene function or expression. This study advances both of these requirements. Firstly, the use of homologous recombination between the virus genome and plasmids in mammalian cells is a reliable way to engineer HSV such that minimal genome changes are made. This has most frequently been achieved by cotransfection of plasmid and isolated viral genomic DNA, but an alternative is to supply the virus genome by infection in a transfection-infection method. Such approaches can also incorporate CRISPR/Cas9 genome engineering methods. Current descriptions of infection-transfection methods, either with or without the addition of CRISPR/Cas9 targeting, are limited in detail and the extent of optimization. In this study it was found that transfection efficiency and the length of homologous sequences improve the efficiency of recombination in these methods, but the targeting of the locus to be engineered by CRISPR/Cas9 nucleases has an overriding positive impact. Secondly, the intergenic space between UL26 and UL27 was reexamined as a site for the addition of foreign DNA and a position identified that allows insertions without compromising HSV growth in vitro or in vivo.

[The suppression of a herpes simplex virus reproduction with drug resistance by combination 15lys-bis-nt and phosphate of acycloguanosine with some antiherpetic drugs]

Antiherpetic activity of the double and triple combinations, including original connections 15Lys-bis-Nt and phosphate of acycloguanosine (P-ACG), was studied in vitro. For the first time, it was demonstrated that in case of their combined use with known antiherpetic agents, whose activity does not depend on TK of HSV (PFA, AraA, CDV, Rib, GLN, αa-IFN), synergistic or additive effects of interaction was observed. The antiviral effect of the tested combinations was studied on the model of ACG-resistant viral strain. The tested combinations could be of interest for practical medicine.

[A study of the antiherpetic activity of the chaga mushroom (Inonotus obliquus) extracts in the Vero cells infected with the herpes simplex virus]

The chaga mushroom (Inonotus obliquus) contains a wide range of excellent bioactive compounds. However, limited information exists on the antiviral activity of the compounds extracted from chaga. A number of subfractions of chaga were obtained using different solvents and different procedures. The subfractions of chaga extracted with water, alcohol, alkali were tested for their toxicity for the Vero cell culture and antiviral effect in the Vero cells infected with the Herpes simplex virus (HSV), Type 1. It was shown that most of the subfractions were not toxic for the Vero cells and had protective effect on the Vero cells infected with HSV. The subfraction IV in the concentration 5 microg/ml protected the Vero cells from cytodestructive action of HSV and no viral DNA was detected in infected cells treated with chaga extracts. Best protective effect was observed when compound was added before or within one hour after the Vero cells were infected with HSV.

Herpes simplex virus dances with amyloid precursor protein while exiting the cell

Herpes simplex type 1 (HSV1) replicates in epithelial cells and secondarily enters local sensory neuronal processes, traveling retrograde to the neuronal nucleus to enter latency. Upon reawakening newly synthesized viral particles travel anterograde back to the epithelial cells of the lip, causing the recurrent cold sore. HSV1 co-purifies with amyloid precursor protein (APP), a cellular transmembrane glycoprotein and receptor for anterograde transport machinery that when proteolyzed produces A-beta, the major component of senile plaques. Here we focus on transport inside epithelial cells of newly synthesized virus during its transit to the cell surface. We hypothesize that HSV1 recruits cellular APP during transport. We explore this with quantitative immuno-fluorescence, immuno-gold electron-microscopy and live cell confocal imaging. After synchronous infection most nascent VP26-GFP-labeled viral particles in the cytoplasm co-localize with APP (72.8+/−6.7%) and travel together with APP inside living cells (81.1+/−28.9%). This interaction has functional consequences: HSV1 infection decreases the average velocity of APP particles (from 1.1+/−0.2 to 0.3+/−0.1 µm/s) and results in APP mal-distribution in infected cells, while interplay with APP-particles increases the frequency (from 10% to 81% motile) and velocity (from 0.3+/−0.1 to 0.4+/−0.1 µm/s) of VP26-GFP transport. In cells infected with HSV1 lacking the viral Fc receptor, gE, an envelope glycoprotein also involved in viral axonal transport, APP-capsid interactions are preserved while the distribution and dynamics of dual-label particles differ from wild-type by both immuno-fluorescence and live imaging. Knock-down of APP with siRNA eliminates APP staining, confirming specificity. Our results indicate that most intracellular HSV1 particles undergo frequent dynamic interplay with APP in a manner that facilitates viral transport and interferes with normal APP transport and distribution. Such dynamic interactions between APP and HSV1 suggest a mechanistic basis for the observed clinical relationship between HSV1 seropositivity and risk of Alzheimer's disease.

Complementation of a herpes simplex virus ICP0 null mutant by varicella-zoster virus ORF61p

The herpes simplex virus (HSV) ICP0 protein acts to overcome intrinsic cellular defenses that repress viral alpha gene expression. In that vein, viruses that have mutations in ICP0's RING finger or are deleted for the gene are sensitive to interferon, as they fail to direct degradation of promyelocytic leukemia protein (PML), a component of host nuclear domain 10s. While varicella-zoster virus is also insensitive to interferon, ORF61p, its ICP0 ortholog, failed to degrade PML. A recombinant virus with each coding region of the gene for ICP0 replaced with sequences encoding ORF61p was constructed. This virus was compared to an ICP0 deletion mutant and wild-type HSV. The recombinant degraded only Sp100 and not PML and grew to higher titers than its ICP0 null parental virus, but it was sensitive to interferon, like the virus from which it was derived. This analysis permitted us to compare the activities of ICP0 and ORF61p in identical backgrounds and revealed distinct biologic roles for these proteins.

Evidence for the potential influence of cyclic nucleotides on maintenance of or reactivation from latency of herpes simplex virus in trigeminal ganglionic neurons

Herpes simplex virus infections are epidemic throughout developed countries, and recurrent herpes simplex keratitis is the most common cause of corneal blindness in these countries, NIH (1973). No available antiviral agent is capable of eradicating the state of viral ganglionic latency, and hence no effective treatment currently exists for prevention of viral re-activation from latency, with resultant recurrent infectious viral clinical manifestations. Putative triggers of re-activation include stress, sunburn, menses, trauma, and fever. These 'triggers' seem to share at least one common characteristic: the potential ability to influence intracellular cyclic nucleotide levels through the action of such first order messengers as catacolamines (stress, trauma) and/or arachadonic acid metabolites (sunburn, fever, trauma, and menses). We exploited an in vitro model of HSV ganglionic latency, and developed a model of in vitro organ culture ganglionic viral reactivation from latency. We then examined the effect of a variety of agents on this model. We found that agents which have been shown to elevate cyclic AMP levels consistently produce increased viral shedding (compared to control, spontaneous reactivation rate) in our model of viral reactivation from latency. In contrast, agents which have been shown to depress c-AMP levels and/or to elevate c-GMP levels inhibit viral reactivation from latency in this in vitro model. We conclude that intracellular cyclic nucleotide levels may influence events which control herpes simplex genome transcription.

Extraneuronal herpetic latency: animal and human corneal studies

HSV DNA has been previously detected by both in situ and dot blot hybridization in neuronal tissues latently infected with herpes simplex virus (HSV), but not in extraneuronal tissues. The present study, using dot blot hybridization with a cloned full-length HSV DNA probe and subtractive hybridization assays for detecting HSV RNA, reveals both the presence and activity of the HSV genome in 100% of HSV latently infected rabbit corneas tested. Studies on human herpetic corneas taken at keratoplasty using slot blot hybridization with a cloned full-length HSV DNA probe demonstrated positive binding (hybridization) to the probe in 50% of samples tested but no binding to normal human control DNA. These studies confirm earlier, less sensitive virus recovery assays and implicate the cornea as an extraneuronal site of HSV latency and reactivation.

[Characterization and antimicrobial activity of the bioactive metabolites in streptomycete isolates]

Twenty different streptomycete isolates were obtained from soils of southeast Serbia. Five isolates identified as Streptomyces hygroscopicus (SH100, SH101, SH102, SH103, and SH104) showed strong activity against Botrytis cinerea, a parasite found in domestic vines. These isolates were extensively studied for their in vitro antimicrobial activity against Gram-positive bacteria, Gram-negative bacteria, yeasts and fungi, and also antiviral activity against Herpes simplex. The results indicated that the obtained isolates were highly active against Botrytis cinerea, Candida albicans, and Herpes simplex, with an inhibition zone of approximately 31 mm. The structure of the bioactive components was determined using elemental analysis, as well as UV/VIS, FTIR, and TLC.

Pinastric acid revisited: a complete NMR and X-ray structure assignment

Chemical investigation of a terrestrial lichen has yielded the pulvinic acid derivative pinastric acid (4). The structure of 4 was secured by detailed spectroscopic analysis as well as via a single X-ray diffraction study. This is the first report of the X-ray structure and 2D NMR assignment of pinastric acid (4). Pinastric acid (4) displayed antitumour, antiviral and antimicrobial (both antibacterial and antifungal) activities. Whilst the antiviral and antimicrobial activities are consistent with previous findings of 4 this is the first report of the antitumour properties for the compound.

Bioreactor production of recombinant herpes simplex virus vectors

Serotypical application of herpes simplex virus (HSV) vectors to gene therapy (type 1) and prophylactic vaccines (types 1 and 2) has garnered substantial clinical interest recently. HSV vectors and amplicons have also been employed as helper virus constructs for manufacture of the dependovirus adeno-associated virus (AAV). Large quantities of infectious HSV stocks are requisite for these therapeutic applications, requiring a scalable vector manufacturing and processing platform comprised of unit operations which accommodate the fragility of HSV. In this study, production of a replication deficient rHSV-1 vector bearing the rep and cap genes of AAV-2 (denoted rHSV-rep2/cap2) was investigated. Adaptation of rHSV production from T225 flasks to a packed bed, fed-batch bioreactor permitted an 1100-fold increment in total vector production without a decrease in specific vector yield (pfu/cell). The fed-batch bioreactor system afforded a rHSV-rep2/cap2 vector recovery of 2.8 x 10(12) pfu. The recovered vector was concentrated by tangential flow filtration (TFF), permitting vector stocks to be formulated at greater than 1.5 x 10(9) pfu/mL.

Anti-herpes simplex virus activities of two novel disulphated cyclitols

By screening a library of sulphated compounds of low molecular weight, we have found that several cyclitol derivatives, each modified with two sulphate groups in addition to pyrrole and various aromatic moieties, inhibited infectivity of herpes simplex virus (HSV) at concentrations approximately 100 times lower than those toxic for cultured cells. These disulphated cyclitols interfered with HSV-1 attachment to cells, and efficiently reduced the cell-to-cell spread of the virus. This effect is most likely due to their low molecular weight and associated with the compounds' capability to access the narrow intercellular spaces. Furthermore, these disulphated cyclitols also inactivated infectivity of HSV. However, the virus-inactivating activities of these compounds were to some extent diminished in the presence of human cervical secretions or other protein-rich solutions suggesting that disulphated cyclitols may have some features of surfactant-type virucides. In conclusion, this new class of anti-HSV compounds offers potential for further development.

Herpes simplex virus hepatitis: expanding the spectrum of disease

We describe 2 transplant patients with herpes simplex virus (HSV) hepatitis who were minimally symptomatic throughout their illness. The spectrum of disease caused by HSV hepatitis is more variable than previously reported in this population. HSV hepatitis should be considered in immunocompromised hosts with elevated transaminases without evidence of fulminant hepatic necrosis.

Virucidal activity of a GT-rich oligonucleotide against herpes simplex virus mediated by glycoprotein B

We have investigated the antiviral mechanism of a phosphorothioate oligonucleotide, ISIS 5652, which has activity against herpes simplex virus (HSV) in the low micromolar range in plaque reduction assays. We isolated a mutant that is resistant to this compound. Marker rescue and sequencing experiments showed that resistance was due to at least one of three mutations in the UL27 gene which result in amino acid changes in glycoprotein B (gB). Because gB has a role in attachment and entry of HSV, we tested the effects of ISIS 5652 at these stages of infection. The oligonucleotide potently inhibited attachment of virus to cells at 4 degrees C; however, the resistant mutant did not exhibit resistance at this stage. Moreover, a different oligonucleotide with little activity in plaque reduction assays was as potent as ISIS 5652 in inhibiting attachment. Similarly, ISIS 5652 was able to inhibit entry of pre-attached virions into cells at 37 degrees C, but the mutant did not exhibit resistance in this assay. The mutant did not attach to or enter cells more quickly than did wild-type virus. Strikingly, incubation of wild-type virus with 1 to 2 microM ISIS 5652 at 37 degrees C led to a time-dependent, irreversible loss of infectivity (virucidal activity). No virucidal activity was detected at 4 degrees C or with an unrelated oligonucleotide at 37 degrees C. The resistant mutant and a marker-rescued derivative containing its gB mutations exhibited substantial resistance to this virucidal activity of ISIS 5652. We hypothesize that the GT-rich oligonucleotide induces a conformational change in gB that results in inactivation of infectivity.

Establishment and characterization of a novel genetic hybrid cell line for propagation of four pathogens

Chromosomal DNAs were purified from human epidermoid carcinoma (HEP-2) cells and transfected into human embryonic lung (HEL) cells to establish a genetic hybrid cell line susceptible to infections by toxoplasma, rubella virus, cytomegalovirus, and herpes simplex virus. Karyotype analysis showed that the resultant hybrid cells, designated D3, had a chromosome number of 96, which was stable after passage for 100 generations. Direct microscopy and immunofluorescence showed that the D3 cells could be infected by the four pathogens with overt cytopathic effects. The toxoplasma and three viruses were purified from infected D3 cells by sucrose gradient centrifugation and used as the antigens for detection of specific IgG and/or IgM in serum samples from pregnant women with suspicious infections by the four pathogens, the results of which were consistent with those of commercial kits. These data indicate that a stable genetic hybrid cell line has been generated, which is a valuable tool for the isolation of the four intrauterine pathogens and for the preparation of antigens for serological tests.

Phosphorylation of the herpes simplex virus tegument protein VP22 has no effect on incorporation of VP22 into the virus but is involved in optimal expression and virion packaging of ICP0

Herpes simplex virus VP22 is a major tegument protein of unknown function. Very recently, we reported that the predominant effect of deleting the VP22 gene was on the expression, localization, and virion incorporation of ICP0. In addition, the Delta22 virus replicated poorly in epithelial MDBK cells. We have also previously shown that VP22 interacts with the tegument protein VP16 and the cellular microtubule network. While the majority of VP22 in infected cells is highly phosphorylated, the nonphosphorylated form of VP22 is the predominant species in the virion, suggesting a differential requirement for phosphorylation through virus replication. Hence, to study the significance of VP22 phosphorylation, we have now constructed two recombinant viruses expressing green fluorescent protein-VP22 (G22) in which the previously identified serine phosphorylation sites have been mutated either to alanine to abolish the phosphorylation status of VP22 (G22P-) or to glutamic acid to mimic permanent phosphorylation (G22P+). Localization studies indicated that the G22P- protein associated tightly with microtubules in some infected cells, suggesting that VP22 phosphorylation may control its interaction with the microtubule network. By contrast, VP22 phosphorylation had no effect on its ability to interact with VP16 and, importantly, had no effect on the relative packaging of VP22. Intriguingly, virion packaging of ICP0 was reduced in the G22P+ virus while ICP0 expression was reduced in the G22P- virus, suggesting that these two ICP0 defects, previously observed in the Delta22 virus, were attributable to different forms of VP22. Furthermore, the Delta22 virus replication defect in MDBK cells correlated with the expression of constitutively charged VP22 in the G22P+ virus. Taken together, these results suggest an important role for VP22 phosphorylation in its relationship with ICP0.

Effect of chemotherapy-induced DNA repair on oncolytic herpes simplex viral replication

BACKGROUND

Gliomas treated with the alkylating agent temozolomide have incomplete responses in part because of tumoral repair of chemotherapy-induced DNA damage. Data from phase I trials suggest that G207, an oncolytic herpes simplex virus (HSV) with mutated ribonucleotide reductase (RR) and gamma34.5 genes, is safe but needs greater viral oncolysis to be effective. We hypothesized that temozolomide and G207 treatment limitations could be jointly addressed using temozolomide-induced tumor-protective DNA repair pathways to enhance viral replication.

METHODS

Human glioblastoma cells (U87, T98, and U373) and U87 cells transfected with the gene for the DNA repair enzyme O6-methylguanine DNA methyltransferase (MGMT) were treated with G207 and/or temozolomide. Drug interactions, expression of the growth arrest DNA damage 34 (GADD34) and RR transcripts before and after their knockdown with short interfering RNAs, DNA strand breaks, and apoptosis were measured using Chou-Talalay analysis, real-time reverse transcription-polymerase chain reaction, the comet assay, and flow cytometry, respectively. Survival of mice (groups of ten) with intracranial U87 xenograft tumors treated with temozolomide and/or G207 was analyzed using Kaplan-Meier analysis.

RESULTS

Temozolomide exhibited strong synergy with G207 in both MGMT-negative and the MGMT inhibitor O6-benzylguanine-treated MGMT-expressing gliomas (Chou-Talalay combination indices = 0.005 to 0.39) and induced GADD34 expression primarily in nonapoptotic MGMT-negative U87 glioma cells (fold difference = 16, 95% confidence interval [CI] = 12.6 to 20.4, compared with untreated cells). MGMT-expressing T98 and U87/MGMT cells treated with temozolomide plus O6-benzylguanine had higher RR expression than untreated cells (fold difference =14.9, 95% CI = 10.1 to 22.0 [T98]; 9.9, 95% CI = 7.0 to 13.8 [U87/MGMT]). GADD34 and RR knockdown increased temozolomide-induced DNA damage and inhibited the synergy of G207 and temozolomide in U87 and O6-benzylguanine-treated U87/MGMT cells. Mice bearing intracranial U87 tumors survived longer after combination therapy (100% survival at 90 days) than after single-agent therapy (median survival = 46 and 48 days with G207 and temozolomide treatment, respectively).

CONCLUSIONS

Temozolomide-induced DNA repair pathways vary with MGMT expression and enhance HSV-mediated oncolysis in glioma cells. These findings unveil the potential of HSV to target cells surviving temozolomide treatment.

Enhanced nectin-1 expression and herpes oncolytic sensitivity in highly migratory and invasive carcinoma

PURPOSE

Although a variety of malignant tumors are susceptible to therapy with oncolytic herpes simplex viruses, the determinants of tumor sensitivity to these viruses are poorly understood. Nectin-1 is a cell surface adhesion molecule that is a component of intercellular adherens junctions and also functions as a herpes viral receptor. Because highly invasive cells may have decreased intercellular adhesion, we sought to determine if such cells might also have altered availability of cell surface nectin-1 to act as a herpes receptor.

EXPERIMENTAL DESIGN AND RESULTS

A series of squamous cell carcinoma lines of increasing migratory and invasive potential, termed MG1-MG14, were selected by serial passages of murine SCC7 through Matrigel invasion chambers. Available cell surface nectin-1 was enhanced on the MG11 and MG14 cell lines in comparison to SCC7 as measured by cellular ELISA and immunofluorescence microscopy. A replication-competent, oncolytic herpes virus (NV1023) showed an increased ability to enter MG11 and MG14 cells as compared with SCC7 cells. Furthermore, MG11 and MG14 supported increased herpes viral replication and cytotoxicity over SCC7. For all three of the cell lines, viral entry assays revealed that the actively migrating cells were significantly more susceptible to herpes infection than the nonmigrating cells.

CONCLUSIONS

These results show that malignant cells with highly migratory and invasive properties may exhibit increased cell surface nectin-1 availability, which may serve as a herpes viral receptor to enhance the efficacy of herpes oncolytic therapy. This finding has implications regarding patient selection for future clinical trials using these promising therapeutic vectors.

Phosphorylation of the VP16 transcriptional activator protein during herpes simplex virus infection and mutational analysis of putative phosphorylation sites

VP16 is a virion phosphoprotein of herpes simplex virus and a transcriptional activator of the viral immediate-early (IE) genes. We identified four novel VP16 phosphorylation sites (Ser18, Ser353, Ser411, and Ser452) at late times in infection but found no evidence of phosphorylation of Ser375, a residue reportedly phosphorylated when VP16 is expressed from a transfected plasmid. A virus carrying a Ser375Ala mutation of VP16 was viable in cell culture but with a slow growth rate. The association of the mutant VP16 protein with IE gene promoters and subsequent IE gene expression was markedly reduced during infection, consistent with prior transfection and in vitro results. Surprisingly, the association of Oct-1 with IE promoters was also diminished during infection by the mutant strain. We propose that Ser375 is important for the interaction of VP16 with Oct-1, and that the interaction is required to enable both proteins to bind to IE promoters.

Herpes simplex virus: propagation, quantification, and storage

Herpes simplex virus (HSV) is the prototype of a family of large, enveloped, double-stranded DNA viruses, the Herpesviridae, which cause significant morbidity and mortality in humans. Productive replication of HSV in cells in culture results in definitive changes in cellular physiology and metabolism, ultimately leading to lysis. These definitive aspects of viral-host interactions enable diagnosis of HSV infections. In this unit, a series of methods are described for the propagation, quantification, and storage of HSV. Infectious center assays are used to measure the titers of HSV stocks. In addition, immunological methods are described for documenting the accumulation of viral polypeptides in infected whole cell extracts, as well as in situ using indirect immunofluorescence. These techniques should be beneficial to basic research virologists utilizing standard laboratory HSV strains, as well as clinical microbiologists interested in characterizing HSV isolated from patients.

Herpes Simplex Virus Infections in Neonates and Early Childhood

Of the commonly considered congenital infections, those caused by cytomegalovirus (CMV), syphilis, and herpes simplex virus (HSV) are frequently (CMV, HSV) or exclusively (syphilis) acquired sexually by the mother, with subsequent transmission to the developing fetus. Of the other commonly considered congenital infections, including rubella and toxoplasma infections, the mother is exposed to the infectious agent via interpersonal or environmental contacts. Unlike each of these other pathogens, which are transmitted transplacentally to the developing fetus following maternal infection though, HSV usually is transmitted perinatally as the neonate is exposed to the virus during passage through an infected birth canal. This difference in timing of acquisition of infection has had important consequence in the therapeutic advances achieved during the last 30 years in the management of neonatal HSV infections. Because the time period between the acquisition of infection and initiation of effective antiviral therapy is shorter in neonatal herpes than in congenital toxoplasmosis or CMV infections, the outcomes of therapy have the potential to be markedly different. This article will summarize the current state of neonatal HSV disease presentation, diagnosis, and management.

Recombinant interleukin-2 enhanced the antitumor effect of ADV/RSV-HSV-tk/ACV therapy in a murine bladder cancer model

BACKGROUND

Previous studies demonstrated the antitumor effects of IL-2 and ADV/RSV-HSV-tk in bladder tumor models. In our study, we employed the intramuscular injection of recombinant IL-2 combined with ADV/RSV-HSV-tk gene therapy in the MBT-2 murine bladder tumor model.

MATERIALS AND METHODS

In the in vitro study, after adenoviral gene transduction efficiency had been assessed, the cytotoxicity of ADV/RSV-HSV-tk/ACV was examined. In the in vivo study, ADV/RSV-HSV-tk was injected into MBT-2 subcutaneous tumors, ACV was injected intraperitoneally daily for 13 days and recombinant IL-2 was injected intramuscularly daily for 10 days.

RESULTS

The X-gal staining of MBT-2 cells infected with 125 multiplicity of injection (MOI) indicated > 20% adenoviral gene transduction efficiency. The cell growth of MBT-2 infected with 125 MOI was significantly inhibited by 40 microM of ACV. In the in vivo study, the combination therapy significantly inhibited tumor growth in the MBT-2 tumor model.

CONCLUSION

The systemic administration of recombinant IL-2 in combination with HSV-tk gene therapy exhibited an enhanced antitumor effect.

Optimal design and efficiency of two-phase case-control studies with error-prone and error-free exposure measures

This paper addresses optimal design and efficiency of two-phase (2P) case-control studies in which the first phase uses an error-prone exposure measure, Z, while the second phase measures true, dichotomous exposure, X, in a subset of subjects. Optimal design of a separate second phase, to be added to a preexisting study, is also investigated. Differential misclassification is assumed throughout. Results are also applicable to 2P cohort studies with error-prone and error-free measures of disease status but error-free exposure measures. While software based on the mean score method of Reilly and Pepe (1995, Biometrika 82, 299--314) can find optimal designs given pilot data, the lack of simple formulae makes it difficult to generalize about efficiency compared to one-phase (1P) studies based on X alone. Here, formulae for the optimal ratios of cases to controls and first- to second-phase sizes, and the optimal second-phase stratified sampling fractions, given a fixed budget, are given. The maximum efficiency of 2P designs compared to a 1P design is deduced and is shown to be bounded from above by a function of the sensitivities and specificities of Z. The efficiency of 'balanced' separate second-phase designs (Breslow and Cain, 1988, Biometrika 75, 11--20)-in which equal numbers of subjects are chosen from each first-phase strata-compared to optimal design is deduced, enabling situations where balanced designs are nearly optimal to be identified.

Antimicrobial activity of UMFix tissue fixative

AIMS

The aim of this study was to determine the antimicrobial effects of UMFix, an alcohol based tissue fixative, on various microorganisms. The UMFix solution was compared with 10% neutral buffered formalin.

METHODS

Standard methods to determine microorganism colony counts were performed after exposure of the microorganisms to UMFix and 10% neutral buffered formalin.

RESULTS

After a short exposure, UMFix rapidly killed vegetative bacteria, yeasts, moulds, and viruses. Bacterial spores were resistant to killing by UMFix. All organisms were killed by the 10% neutral buffered formalin preparation.

CONCLUSIONS

UMFix was microbicidal for vegetative bacteria, yeasts, and aspergillus species after a short exposure, although it was not active against spore forming bacillus species. The methanol content of the fixative was responsible for the killing effect of this fixative. No killing was seen when polyethylene glycol was used alone.

Pulmonary pathology of severe acute respiratory syndrome in Toronto

The severe acute respiratory syndrome (SARS) pandemic in Toronto resulted in a large number of autopsies on its victims. We describe the pulmonary pathology of patients who died in the 2003 Toronto outbreak. Autopsy material from the lungs of 20 patients who died between March and July 2003 were characterized by histology, molecular biology, and immunohistochemistry for cytokeratins, thyroid transcription factor-1, CD68, Epstein-Barr virus, cytomegalovirus, and human herpes simplex viruses. Matched controls were obtained from patients who died of other causes over the same interval. The mean duration of illness was 27 days (range 5-108 days). Post-mortem lung tissues from 19 of 20 patients with probable SARS were positive for SARS-associated coronavirus by RT-PCR. Histologically, all patients showed varying degrees of exudative and proliferative phase acute lung injury, evidenced in conventional and immunohistochemical stains by edema, inflammatory infiltrate, pneumocyte hyperplasia, fibrinous exudates, and organization. Eight of 20 patients showed predominantly a diffuse alveolar damage pattern of acute lung injury, six showed predominantly an acute fibrinous and organizing pneumonia pattern, and the remainder showed an admixture of the two patterns. Squamous metaplasia and scattered multinucleate giant cells were present in most cases. Vascular fibrin thrombi were a common finding and were often associated with pulmonary infarcts. Special stains demonstrated vascular endothelial damage of both small- and mid-sized pulmonary vessels. Two cases were complicated by invasive fungal disease consistent with Aspergillosis, and another by coinfection with cytomegalovirus. Our findings indicate that the lungs of patients who die of SARS are almost always positive for the SARS-associated coronavirus by RT-PCR, and may show features of both diffuse alveolar damage and acute fibrinous and organizing pneumonia patterns of acute injury. Cases of SARS may be complicated by coexistent infections and therapy-related lung injury.

Dendritic Cells Exposed to Herpes Simplex Virus In Vivo Do Not Produce IFN-α after Rechallenge with Virus In Vitro and Exhibit Decreased T Cell Alloreactivity

Plasmacytoid dendritic cells (DC) are known to produce large amounts of IFN-alpha when stimulated with virus in vivo and in vitro. Immunohistological staining of spleens from mice taken at different times after HSV infection revealed an early infiltration of plasmacytoid DC whereas both the myeloid DC and lymphoid-related DC had different kinetics. Upon rechallenge with virus in vitro, total splenic DCs from viral-infected mice were unable to produce IFN-alpha when compared with DC from mice that received an initial in vivo injection with PBS. Furthermore, DC from mice that were infected with increasing doses of HSV expressed high levels of accessory and activation molecules compared with control mice. However, when cultured in vitro together with allogeneic T cells, DC from mice that had been exposed to the highest viral titers in vivo induced the lowest levels of T cell proliferation. DC exposed to PBS in vivo promoted a Th1 response upon coculture with CD4(+) T cells whereas T cells cultured with DC exposed to increasing viral titers in vivo resulted in a gradually decreased Th1 response. The data suggest HSV induces DC maturation and at higher titers, exhaustion, diminishing T cell proliferation, and IFN-gamma secretion.

Famciclovir Suppression of Asymptomatic and Symptomatic Recurrent Anogenital Herpes Simplex Virus Shedding in Women: A Randomized, Double‐Blind, Double‐Dummy, Placebo‐Controlled, Parallel‐Group, Single‐Center Trial

Genital herpes is most often transmitted while the patient is asymptomatic, presumably during episodes of viral shedding. To determine whether famciclovir is effective in reducing asymptomatic shedding, women with frequent, recurrent genital outbreaks were enrolled in a randomized, double-blind, double-dummy, placebo-controlled, parallel-group, 112-day trial of suppressive treatment with famciclovir for anogenital viral shedding. Sixty women received 125 mg of famciclovir 3 times daily, 59 received 250 mg of famciclovir 3 times daily, and 58 received placebo. Patients recorded symptoms and self-obtained cultures daily. Famciclovir reduced asymptomatic shedding, compared with placebo (P < .0001). The onset of asymptomatic shedding was also delayed (P < .0001). Famciclovir reduced symptomatic shedding in a dose-dependent manner (0.72% for 125 mg 3 times daily vs. 0.19% for 250 mg 3 times daily [P < .0001] vs. 5.53% for placebo [P < .0001]). In conclusion, suppressive treatment with famciclovir reduced both asymptomatic and symptomatic viral shedding and delayed the onset of asymptomatic shedding in women with frequently recurring genital herpes. Studies to examine the effects of suppression by famciclovir on the transmission of genital herpes are warranted.

Shear-induced release of disabled herpes simplex virus from baby-hamster kidney cells

A new process route is proposed to increase the production yield of disabled herpes simplex virus type 1 (HSV-1 DIS). Infected baby-hamster kidney (BHK) cells were subjected to a range of shear rates between 3.69 x 10(3) s(-1) and 51.3 x 10(3) s(-1) in the gap between a pair of co-axial cylinders. Analysis of the supernatant fractions of sheared material established that optimal virus release was achieved by exposing the infected cells to a shear rate of 42.7 x 10(3) s(-1) for a period of 1 min. Compared with the current laboratory process, the titre of HSV-1 DIS was increased over 30-fold, from about 1 x 10(6) to 30 x 10(6) pfu (plaque-forming units)/ml. Evaluation of the supernatant fractions by flow cytometry, total protein assay, PAGE and dot-blot assays showed no evidence of cell disruption, supporting the hypothesis that shear-induced release of the cell-membrane-bound virus was achieved without compromising downstream purification. The proposed method is scalable, and since no additional chemicals are required, it provides an attractive option for enhanced recovery of virus particles for therapeutic applications.

In vitro anti-herpes simplex viruses and anti-adenoviruses activity of twelve traditionally used medicinal plants in Taiwan

As an effort to search for new antiviral agents from traditional medicine, the hot water (HW) extract of twelve traditionally used medicinal plants in Taiwan was evaluated for their in vitro anti-herpes simplex viruses (HSV; including HSV-1 and HSV-2) and anti-adenoviruses (ADV; including ADV-3, ADV-8 and ADV-11) activities with a XTT-based colorimetric assay. Results showed that the tested HW extracts exhibited anti-HSV and anti-ADV activities at different magnitudes of potency. Among the twelve medicinal plants, Boussingaultia gracilis var. pseudobaselloides (Basellaceae) and Serissa japonica (Rubiaceae) possessed broad spectrum of antiviral activity. Ardisia squamulosa (Myrsinaceae) and Artemisai princeps var. orientalis (Compositae) were more effective in inhibiting ADV-8 replication than the other four viruses. Cell cytotoxic assay demonstrated that all tested HW extracts had CC50 values higher than their EC50 values. It was concluded that the twelve traditionally used medicinal plants in Taiwan possessed antiviral activity, and some of them merit further investigation.

Valacyclovir for the suppression of recurrent genital herpes in human immunodeficiency virus-infected subjects

To determine the efficacy and safety of valacyclovir (500 mg twice daily) for the suppression of recurrent genital herpes simplex virus infections in human immunodeficiency virus (HIV)-infected subjects, a randomized, double-blind, placebo-controlled, multicenter international trial was conducted. A total of 293 HIV-seropositive subjects receiving antiretroviral therapy were enrolled. The proportion of subjects who did not have a recurrence of genital herpes at 6 months was 65% among valacyclovir recipients versus 26% among placebo recipients (relative risk, 2.5; 95% confidence interval, 1.8-3.5). The time to first genital herpes recurrence was significantly shorter in the placebo group (median, 59 days) than in the valacyclovir group (median, >180 days). Valacyclovir was well tolerated; the incidence of adverse events for the 2 treatment groups was similar when the duration of treatment was considered. There were no episodes of thrombotic microangiopathy. Valacyclovir was safe and effective for the suppression of recurrent genital herpes infection in HIV-infected individuals.

The herpes simplex virus (HSV) protein ICP34.5 is a virion component that forms a DNA-binding complex with proliferating cell nuclear antigen and HSV replication proteins

The replicative ability of ICP34.5-null herpes simplex virus (HSV) is cell type and state dependent. In certain cells, ICP34.5 interacts with protein phosphatase 1 to preclude host cell protein synthesis shutoff by dephosphorylation of the eukaryotic initiation factor eIF-2alpha. However, host cell shutoff is not induced by ICP34.5-null HSV in most cells, irrespective of type and state. In general, dividing cells support replication of ICP34.5-null HSV; nondividing cells cannot. Previously the authors showed that ICP34.5 binds to proliferating cell nuclear antigen (PCNA), a protein necessary for cellular DNA replication and repair. Here the authors demonstrate that (1) the interaction between ICP34.5 and PCNA involves two regions of the virus protein; (2) ICP34.5 forms a complex with HSV replication proteins that is DNA binding; (3) at early times in infection, ICP34.5 colocalizes with PCNA and HSV replication proteins in cell nuclei, before accumulating in the cytoplasm; and (4) ICP34.5 is a virion protein. In light of ongoing clinical trials assessing the safety and efficacy of ICP34.5-null HSV, it is vital that the roles of ICP34.5 in HSV replication are understood. The authors propose that in nondividing cells, ICP34.5 is required to switch PCNA from repair to replication mode, a prerequisite for the initiation of HSV replication.

Disabled infectious single cycle herpes simplex virus (DISC-HSV) is a candidate vector system for gene delivery/expression of GM-CSF in human prostate cancer therapy

BACKGROUND

DISC-HSV is a replication incompetent herpes simplex virus that is a highly efficient vector for the transduction of genes in vivo and in vitro. We examine the ability of DISC-HSV to infect human prostate cancer cell-lines and xenograft tumor models, and induce expression of reporter and therapeutic cytokine genes.

METHODS

Infection was confirmed by cellular staining for the beta-galactosidase reporter gene product, and by EM. Human GM-CSF production following DISC-hGMCSF infection was measured using ELISA. The metabolic activity of infected cells was determined by NADP/NADPH assay. Cell death was estimated by cell-cycle analysis using flow cytometry with propidium iodide staining.

RESULTS

Infection of DU145, PC3 and LNCaP cells with DISC-HSV was dose dependent. Cells infected with DISC-hGM-CSF released significant levels of hGM-CSF for 3 days. NADP/NADPH assay suggested that infected cells continued to be metabolically active for 3 days post-infection, which was consistent with flow cytometry findings that cell death did not occur within 7 days of infection. Tumor xenografts injected with DISC-HSV expressed beta-galactosidase, and intracellular viral particles were demonstrated using EM.

CONCLUSIONS

We have previously reported the rejection of established tumors following intra-tumoral injection of DISC-GMCSF. This study demonstrates the ability of DISC-HSV to infect prostate cancer and express GMCSF at significant levels. We suggest that prostate cancer is a potential target for therapy using DISC-HSV containing GM-CSF.

Dynamics of herpes simplex virus capsid maturation visualized by time-lapse cryo-electron microscopy

The capsid of the herpes simplex virus initially assembles as a procapsid that matures through a massive conformational change of its 182 MDa surface shell. This transition, which stabilizes the fragile procapsid, is facilitated by the viral protease that releases the interaction between the shell and the underlying scaffold; however, protease-deficient procapsids mature slowly in vitro. To study procapsid maturation as a time-resolved process, we monitored this reaction by cryo-electron microscopy (cryo-EM). The resulting images were sorted into 17 distinct classes, and three-dimensional density maps were calculated for each. When arranged in a chronological series, these maps yielded molecular movies of procapsid maturation. A single major switching event takes place at stages 8-9, preceded by relatively subtle adjustments in the pattern of interactions and followed by similarly small 'aftershocks'. The primary mechanism underlying maturation is relative rotations of domains of VP5, the major capsid protein.

Virus-inhibiting surgical glove to reduce the risk of infection by enveloped viruses

Needle puncture and other accidents that occur during surgery and other procedures may lead to viral infections of medical personnel, notably by hepatitis C (HCV) and human immunodeficiency virus (HIV), now that hepatitis B can be prevented by vaccination. A new surgical glove called G-VIR, which contains a disinfecting agent for enveloped viruses, has been developed. Herpes simplex type 1 (HSV) was used as a standard enveloped virus in both in vitro and in vivo tests of the virucidal capacity of the glove. Bovine viral diarrhea virus (BVDV) and feline immunodeficiency virus (FIV) were used as models for HCV and HIV, respectively. For in vitro study, a contaminated needle was passed through a glove and residual virus was titrated; for in vivo studies, animals were stuck with a contaminated needle through a glove. Despite variation in virus enumeration inherent in the puncture technique, statistical evaluation showed that infection was reproducibly and substantially reduced by passage through the virucidal layer. For BVDV, the amount of virus passing through the virucidal glove was reduced in 82% of pairwise comparisons with control gloves that lacked the virucidal agent; when plaque counts were adjusted to a common dilution, the median count for the virucidal glove was on the average reduced >10-fold. In experiments in which the proportion of wells infected with FIV was measured, the ratio of TCID(50) values (control glove to G-VIR) was >15, and probably much higher. For HSV, the amount of virus passing through the virucidal glove was reduced in 81% of comparisons with control gloves; the median of adjusted plaque counts was reduced on the average approximately eightfold or ninefold. In vivo tests with FIV and HSV in cats and mice, respectively, found smaller percentage reductions in infection than the in vitro tests but confirmed the virucidal effect of the gloves.

Potent oncolytic activity of multimutated herpes simplex virus G207 in combination with vincristine against human rhabdomyosarcoma

Replication restricted oncolytic viruses such as multimutated herpes simplex virus type 1 (HSV-1) G207 represent a novel and attractive approach for cancer therapy, including pediatric solid tumors. Rhabdomyosarcoma is the most common soft-tissue sarcoma of childhood and is often diagnosed already as an advanced disseminated disease. Despite aggressive therapeutic approaches, the prognosis for patients with metastatic rhabdomyosarcoma remains grim. Therefore, there is a need for novel effective drugs with superior safety and efficacy profile. In this study, we showed marked in vitro activity of HSV-1 G207 against embryonal and alveolar rhabdomyosarcoma cells. All human embryonal (KF-RMS-1, RD, and CCA) and alveolar RMS (KFR, Rh28, Rh30, and Rh41) cell lines were highly sensitive to cytotoxic and replicative effects of G207 even at a multiplicity of infection of 0.01, except embryonal Rh1 rhabdomyosarcoma cells, which were efficiently killed only upon multiplicity of infection of 1.0. i.v. G207 treatment of xenotransplanted KFR and KF-RMS-1 tumors in mice led to significant tumor growth inhibition of both tumor entities, whereas intraneoplastic G207 treatment additionally resulted in complete tumor disappearance in 25% of animals. No difference has been found between alveolar and embryonal types of rhabdomyosarcoma. Combination treatment of both cell lines with G207 and vincristine led to strongly enhanced in vitro cytotoxicity without affecting infection efficiency and replication of G207 in KFR as well as in KF-RMS-1 cells. In vivo combination treatment using i.v. G207 and vincristine resulted in complete regression of alveolar rhabdomyosarcoma in five of eight animals and significant growth inhibition of embryonal rhabdomyosarcoma. Taking into consideration the proven safety of G207 in humans, we suggest that G207 alone and in combination with vincristine should be additionally evaluated as a potential agent against human rhabdomyosarcoma.

Evaluation of three Copan viral transport systems for the recovery of cultivatable, clinical virus isolates

Three Copan viral transport media (VTM) were compared to the BBL Viral Culturette and Micro Test M4 systems for their ability to maintain the viability of clinical strains of enterovirus, herpes simplex virus, adenovirus and parainfluenza virus. VTM were inoculated, incubated up to 72 h at both 4 degrees C and 22 degrees C, and processed for cell culture. The concentration of infectious virus in VTM was determined by standard endpoint dilution assay. All VTM maintained viable enterovirus and adenovirus for 72 h but adenovirus from M4 and Copan CVM media were detected in cell culture at least one day sooner than from other media. Only M4 and Copan CVM media supported the recognition of low-titer herpes simplex virus in cell culture within 24 h. Parainfluenza virus was consistently detected in culture within six days when maintained in M4 and two of the Copan VTM media. Overall, the Copan CVM compared favorably to the M4 in maintaining concentrations of viable virus that could be recovered and identified rapidly in routine cell culture.

Isolation and characterization of a sulfated polysaccharide from the brown alga Sargassum patens and determination of its anti-herpes activity

Bioactivity-guided fractionation of the hot water extract from the brown alga Sargassun patens led to the isolation of a polysaccharide as an antiviral component against herpes simplex viruses which are the cause of cold sores (HSV-1) and genital herpes (HSV-2). The polysaccharide contained a sulfur group that could be present as a sulfate ester. It is thus a sulfated polysaccharide with a molecular mass of about 424 kDa, and is designated SP-2a. Gas chromatographic assay showed that the polysaccharide consisted of fucose, galactose, mannose, xylose, glucose, and galactosamine. The fucose is the major constituent sugar (35.3%), followed by galactose (18.4%). The 50% effective concentration (EC50) against HSV-2, HSV-1, and HSV-1 acyclovir resistant strain was 1.3, 5.5, and 4.1 microg/mL, respectively. The 50% cytotoxic concentration (CC50) of SP-2a on the growth of normal Vero cell line was more than 4000 microg/mL. Therefore SP-2a of S. patens may be a potent agent for treating HSV infections.

Mapping of functional regions in the amino-terminal portion of the herpes simplex virus ICP27 regulatory protein: importance of the leucine-rich nuclear export signal and RGG Box RNA-binding domain

Infected-cell protein 27 (ICP27) is an essential herpes simplex virus type 1 (HSV-1) regulatory protein that activates a subset of viral delayed-early and late genes, at least in part through posttranscriptional mechanisms. Previous studies have shown that the amino (N)-terminal half of the protein contains important functional regions, including a leucine-rich nuclear export signal (NES). However, to date, the phenotype of an HSV-1 ICP27 NES mutant has not been reported. In this study, we engineered and characterized dLeu, an HSV-1 deletion mutant that specifically lacks ICP27's NES (amino acids 6 to 19). The phenotype of dLeu was analyzed alongside those of eight other ICP27 N-terminal deletion mutants. We found that in Vero cells, dLeu displays modest defects in viral gene expression and an approximately 100-fold reduction in the production of viral progeny. Unlike wild-type (WT) ICP27, which exhibits a cytoplasmic distribution in addition to its predominant nuclear localization, dLeu ICP27 is highly restricted to the cell nucleus. This strongly suggests that the N-terminal leucine-rich sequence functions as an NES during viral infection. Our analysis of dLeu and the other mutants has enabled us to genetically define the regions in the N-terminal 200 residues of ICP27 which are required for efficient viral growth in Vero cells. Only two regions appear to be important: (i) the leucine-rich NES and (ii) the RGG box RNA-binding domain, encoded by residues 139 to 153. A virus lacking the RGG box-encoding sequence, d4-5, has a phenotype similar to that of dLeu in that it displays modest defects in viral gene expression and grows poorly. Interestingly, deletion of both the NES and RGG box, as well as the sequences in between, is lethal. The resulting virus, d1-5, displays severe defects in viral gene expression and DNA synthesis and is unable to produce significant amounts of infectious progeny. Therefore, the N-terminal portion of ICP27 contains at least two functional domains which collectively are absolutely essential for viral infection.

Herpes simplex virus vectors for gene delivery to a variety of different cell types

Herpes Simplex Virus (HSV) has a number of advantages as a gene delivery vector, particularly for the nervous system. Thus, it naturally establishes asymptomatic latent infections of neuronal cells. Moreover, it is readily grown in culture to high titre and has a large genome so allowing it to be used to deliver multiple or very large genes. Considerable progress has been made in effectively disabling the virus so that it does not damage the cells it infects but can still deliver an inserted gene effectively. In addition, it is now possible to obtain long-term expression of the transgene in the nervous system, using regulatory elements derived from the latency-associated transcript of the virus. As well as its use in the nervous system, the virus has also been used to successfully deliver genes to a variety of other cell types, including peripheral blood mononuclear cells and cardiac myocytes within the intact heart. In particular, its ability to deliver genes effectively to replicating cancer cells and to dendritic cells offers considerable potential for the use of this virus in cancer therapy.

Explant-induced reactivation of herpes simplex virus occurs in neurons expressing nuclear cdk2 and cdk4

Herpes simplex virus (HSV) establishes productive (lytic) infections in nonneuronal cells and nonproductive (latent) infections in neurons. It has been proposed that HSV establishes latency because quiescent neurons lack cellular factors required for productive infection. It has been further proposed that these putative factors are induced following neuronal stress, as a requirement for HSV reactivation. To date, the identity of these putative cellular factors remains unknown. We have demonstrated that cyclin-dependent kinase (cdk) 1, 2, or 7 is required for HSV replication in nonneuronal cells. Interestingly, cdks 1 and 2 are not expressed in quiescent neurons but can be induced in stressed neurons. Thus, cdks may be among the cellular proteins required for HSV reactivation whose neuronal expression is differentially regulated during stress. Herein, we determined that neuronal expression of nuclear cdk2, cdk4, and cyclins E and D2 (which activate cdks 2 and 4, respectively) was induced following explant cultivation, a stressful stimulus that induces HSV reactivation. In contrast, neuronal expression of cdk7 and cytoplasmic cdk4 decreased during explant cultivation, whereas cdk3 was detected in the same small percentage of neurons before and after explant cultivation and cdks 1, 5, and 6 were not detected in neuronal cell bodies. HSV-1 reactivated specifically in neurons expressing nuclear cdk2 and cdk4, and an inhibitor specific for cdk2 inhibited HSV-1 reactivation. We conclude that neuronal levels of cdk2 are among the factors that determine the outcome of HSV infections of neurons.