Pronounced Antiviral Effect Research Articles

Unlocking Therapeutic Potential: Enhanced shRNA delivery with Tat peptide in the Human Respiratory Syncytial Virus Treatment

Purpose: This research investigated the development of short hairpin RNA (shRNA) molecules designed to target specific regions of the HRSV M and F genes. The study aimed to assess the therapeutic potential of these shRNAs and evaluate the effectiveness of Tat peptide-mediated delivery in enhancing their functionality. Methods: To investigate the therapeutic potential of short hairpin RNA against HRSV, we acquired isolates from pediatric patients experiencing respiratory illness. These isolates were then cultured in human epidermoid carcinoma cells (HEp-2). To target the M and F genes of HRSV, we constructed plasmids expressing shRNAs. We further investigated the Tat peptide as a facilitator for shRNA plasmid delivery. The cytotoxicity of ribavirin, shRNA constructs, and control agents was assessed using the MTT assay. Next, we compared the transfection efficiency of Tat peptide-mediated shRNA delivery with that of lipofectamine 3000™. Finally, real-time PCR was employed to quantify HRSV replication in the treated cells. Results: Our study successfully demonstrated that Tat peptide-mediated delivery of shRNA plasmids significantly suppressed the expression of the M and F genes of HRSV compared to lipofectamine 3000™. This suppression was evident in both short-term experiments and scenarios involving stable shRNA expression. Furthermore, the combination of ribavirin with shRNA treatment resulted in a substantial reduction in viral load. Notably, the most pronounced antiviral effect was observed when both shRNAs were employed simultaneously. Conclusion: Our findings suggest that Tat peptide-mediated delivery of shRNA plasmids holds significant potential for achieving stable suppression of HRSV genes. This approach warrants further investigation as a potential gene therapy strategy for HRSV. By demonstrating promising results in vitro, this study highlights the need for future in vivo studies to comprehensively evaluate the therapeutic potential of this approach in a clinical setting.

Antiviral properties of diterpenes and their derivatives

The review focuses on low-molecular-weight natural metabolites of the diterpene series and their semi-synthetic analogues, which exhibit antiviral activity. Data on the antiviral activity of both plant extracts and their components are provided. The structures of biologically active natural diterpenoids and their derivatives with a pronounced antiviral effect are presented. Mechanisms of therapeutic action of diterpenoids and their derivatives with a pronounced antiviral effect are considered for different viruses. The review summarizes the data over the last 12 years (2011–2022).<br> The bibliography includes 183 references.

Effect of antiviral siRNAs on the production of cytokines in vitro

Objectives. To evaluate the dynamics of the expression level of IL-1β and IL-28β (IFN-λ3) genes as a result of complex knockdown of some cellular genes, whose expression products play an important role in the reproduction of the influenza virus.Methods. Following the collection of virus-containing liquid and cell lysate within three days from the moment of transfection and infection, the intensity of viral reproduction was assessed using the cytopathic effect titration method. The concentration of viral ribonucleic acid (vRNA) and change in the expression of IL-1β and IL-28β (IFN-λ3) were determined by real-time reverse transcription quantitative polymerase chain reaction (real-time RT-qPCR). The nonparametric Mann–Whitney test was used to statistically calculate significant differences between groups.Results. The use of each small interfering ribonucleic acid (siRNA) complex led to a decrease in viral reproduction on the first day at the multiplicity of infection (MOI) of 0.001. The use of complex A (FLT4.2 + Nup98.1) and D (FLT4.2 + Nup98.1 + Nup205) led to a decrease in viral titer by 2.8 lgTCID50/mL and by 2.1 lgTCID50/mL relative to the use of nonspecific L2 siRNA and viral control (p ≤ 0.05). Transfection of complexes B (Nup98.1 + Nup205) and C (FLT4.2 + Nup205) also reduced the viral titer by 1.5 lgTCID50/mL and 1.8 lgTCID50/mL relative to nonspecific L2 siRNA and viral control (p ≤ 0.05). When conducting real-time RT-qPCR, a significant decrease in the concentration of viral RNA was also noted. When using complexes B, C, and D, the concentration of vRNA decreased on the first day by 14.5, 4.1, and 15 times, respectively. On the second day, a decrease in vRNA was observed in cells with B and D complexes by 17.1 and 18.3 times (p ≤ 0.05). Along with a decrease in the viral titer and vRNA, an increase in the expression of the IL-1β and IL-28β genes was observed on the first day when using all siRNA complexes relative to nonspecific and viral controls (p ≤ 0.05). On the second day, an increase was also observed in cells with A and D complexes, while on the third day, there was an increase in the expression of these genes in cells with complex D (p ≤ 0.05).Conclusions. The use of siRNA complexes is shown to have a pronounced antiviral effect while simultaneously suppressing the activity of cellular genes (FLT4, Nup98 and Nup205). In parallel, the transfection of complexes that block the formation of expression products necessary for viral reproduction is demonstrated to lead to an increase in the level of expression of the IL-1β and IL-28β genes. These results indicate not only that the use of siRNA has antiviral activity, but also immunomodulatory activity, which can contribute to a more effective immune response of the body.

Investigation of the anti-influenza activity of siRNA complexes against the cellular genes <i>FLT4, Nup98</i>, and <i>Nup205 in vitro</i>

Objectives. Evaluation of changes in the viral activity of influenza A/WSN/33 after complex knockdown of combinations of cellular genes FLT4, Nup98 and Nup205 in human lung cell culture A549. Methods. The work was carried out using the equipment of the Center for Collective Use of the I. Mechnikov Research Institute of Vaccines and Sera, Russia. The authors performed transfection of combinations of small interfering ribonucleic acid (siRNA) complexes that cause simultaneous disruption of the expression of cellular genes FLT4, Nup98, and Nup205. Within three days from the moment of transfection and infection, the supernatant fluid and cell lysate were taken for subsequent viral reproduction intensity determination using the titration method for cytopathic action. The dynamics of changes in the concentration of viral ribonucleic acid (vRNA) was determined by real-time reverse transcription polymerase chain reaction (real-time RT-PCR). The nonparametric Mann–Whitney test was used to calculate statistically significant differences between groups.Results. Using all of the combinations of siRNA complexes, cell viability did not decrease below the threshold level of 70%. In cells treated with complex FLT4.2 + Nup98.1 + Nup205 at the multiplicity of infection (MOI) equal to 0.1, a significant decrease in viral reproduction by 1.5 lg was noted on the first day in relation to nonspecific and viral controls. The use of siRNA complexes at MOI 0.01 resulted in a more pronounced antiviral effect. The viral titer in cells treated with siRNA complexes FLT4.2 + Nup98.1 and Nup98.1 + Nup205 decreased by 1.5 lg on the first day. In cells treated with complexes FLT4.2 + Nup205 and FLT4.2 + Nup98.1 + Nup205, it decreased by 1.8 and 2.0 lg on the first day and by 1.8 and 2.5 lg on the second day, respectively, in relation to nonspecific and viral controls. When conducting real-time RT-PCR, a significant decrease in the concentration of vRNA was noted. At MOI 0.1, a 295, 55, and 63-fold decrease in the viral load was observed with the use of siRNA complexes FLT4.2 + Nup98.1, Nup98.1 + Nup205, and FLT4.2 + Nup98.1 + Nup205, respectively. On the second day, a decrease in vRNA was also observed in cells treated with complex A. A 415-fold decrease in vRNA on the third day was noted in cells treated with complex FLT4.2 + Nup205. At MOI 0.01, the concentration of vRNA decreased 9.5 times when using complex B relative to nonspecific and viral control.Conclusions. The study showed a pronounced antiviral effect of siRNA combinations while simultaneously suppressing the activity of cellular genes (FLT4, Nup98, and Nup205), whose expression products are playing important role in the viral reproduction process, and obtained original designs of siRNA complexes. The results obtained are of great importance for the creation of emergence prophylactic and therapeutic drugs, whose action is based on the mechanism of RNA interference.

Anthranilamides with quinoline and β-carboline scaffolds: design, synthesis, and biological activity.

In the present study, we report the design and synthesis of novel amide-type hybrid molecules based on anthranilic acid and quinoline or β-carboline heterocyclic scaffolds. Three types of biological screenings were performed: (i) in vitro antiproliferative screening against a panel of solid tumor and leukemia cell lines, (ii) antiviral screening against several RNA viruses, and (iii) anti-quorum sensing screening using gram-negative Chromobacterium violaceum as the reporter strain. Antiproliferative screening revealed a high activity of several compounds. Anthranilamides 12 and 13 with chloroquine core and halogenated anthranilic acid were the most active agents toward diverse cancer cell lines such as glioblastoma, pancreatic adenocarcinoma, colorectal carcinoma, lung carcinoma, acute lymphoblastic, acute myeloid, chronic myeloid leukemia, and non-Hodgkin lymphoma, but also against noncancerous cell lines. Boc-protected analogs 2 and 3 showed moderate activities against the tested cancer cells without toxic effects against noncancerous cells. A nonhalogenated quinoline derivative 10 with N-benzylanthranilic acid residue was equally active as 12 and 13 and selective toward tumor cells. Chloroquine and quinoline anthranilamides 10–13 exerted pronounced antiviral effect against human coronaviruses 229E and OC43, whereas 12 and 13 against coronavirus OC43 (EC50 values in low micromolar range; selectivity indices from 4.6 to > 10.4). Anthranilamides 14 and 16 with PQ core inhibited HIV-1 with EC50 values of 9.3 and 14.1 µM, respectively. Compound 13 displayed significant anti-quorum/biofilm effect against the quorum sensing reporter strain (IC50 of 3.7 μM) with no apparent bactericidal effect.Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s11030-021-10347-8.

Chemoreactome screening of pharmaceutical effects on SARS-CoV-2 and human virome to help decide on drug-based COVID-19 therapy

Background. So-called rational drug design is suboptimal when it comes to finding effective and safe drug-based treatment for COVID-19. Another approach seems promising: to reprofile the pharmaceuticals registered in the Anatomical, Therapeutic, and Chemical Classifier (ATC).Material and methods. Chemoreactome screening, a method that simulates the results of inhibiting viral growth in a cell culture, models the effects of pharmaceuticals on the human virome, and estimates the adverse effects of medicines, was used to reprofile about 2700 pharmaceuticals from the ATC. The information technology behind chemoreactome analysis is based on the topological recognition theory advanced by the Institute of Pharmaceutical Informatics, Federal Research Center for Informatics and Control, Russian Academy of Sciences.Results. Sixty two pharmaceuticals and 20 micronutrients were found to have a pronounced antiviral effect with minimal side effects. Comparison against data of basic research and clinical trials showed 31 out of 62 pharmaceuticals to have been independently confirmed usable in COVID-19 treatment. These inhibit coronaviral proteins and/or function as adaptogenic molecules that improve the functioning of cells exposed to viral stress. Glucosamine sulfate was found to have the best safety profile and minimum effects on the healthy human virome out of all the tested anticoronaviral micronutrients.Conclusions. Reprofiling of pharmaceuticals registered in the ATC could significantly speed up the search for more effective and safer drugbased COVID-19 treatments. Several micronutrients show promise for long-term coronavirus prevention, especially in the elderly.

Antiviral effect of novel purine conjugate LAS-131 against Herpes simplex virus type 1 (Herpesviridae: Alphaherpesvirinae: Simplexvirus: Human alphaherpesvirus 1) in vitro

Herpes simplex viruses type 1 (HSV-1) are extremely widespread throughout the world and, similar to other herpesviruses, establish lifelong persistent infection in the host. Reactivating sporadically, HSV-1 elicits recurrences in both immunocompetent and immunocompromised individuals and can cause serious diseases (blindness, encephalitis, generalized infections). The currently available antiherpetic drugs that aimed mainly at suppressing replication of viral DNA are not always effective enough, for example, due to the development of drug resistance. As we showed earlier the newly discovered compound LAS-131 exhibits the strong and highly selective inhibitory activity against HSV‑1, including strain resistant to acyclovir (selective index, SI = 63). The presence of LAS-131 at a concentration of 20 μg/ml leads to a decrease in the titer of HSV-1 (strain L2) by 4 lg in a one round of HSV-1 replication. To establish the step(s) of the virus life cycle that is sensitive to the action of LAS-131, we have applied a widely used approach, that made it possible to determine how long the addition of a compound can be postponed before it loses its antiviral activity (time-of-addition assay), and to compare this indicator with the crucial time of application of inhibitors with a well-known mechanism of action (in cell culture). It has been shown for the first time that LAS-131 retains a pronounced antiviral effect when introduced into the experimental system no later than 9 hours post-infection (p.i.). However, LAS-131 does not affect the release of HSV-1 from the cell. Together with published data on the termination of the synthesis of viral DNA 9-12 h after the adsorption in a cell culture infected with HSV with a high multiplicity (≥1 PFU/cell), our results suggest that LAS-131 interferes the life cycle of HSV-1 during synthesis of viral DNA. Further studies of the mechanism of action are necessary to establish definitely the biological target for this compound,.

Химический состав и противовирусные свойства экстрактов плодовых тел гастероидных грибов Западной Сибири

Методами водного и этанольного извлечений получены экстракты плодовых тел грибов гастеромицетов — дождевика грушевидного (Lycoperdon pyriforme) и весёлки обыкновенной (Phallus impudicus). В грибных экстрактах обнаружено наличие белков, полисахаридов, катехинов, танинов, сапонинов и в некоторых экстрактах — флавонолов. Установлено, что все полученные экстракты малотоксичны для культур клеток MDCK и Vero и обладают противовирусной активностью in vitro в отношении вируса гриппа, герпеса 2-го типа и некоторых ортопоксвирусов. Растворы грибных экстрактов оказывают зависимое от концентрации влияние на снижение репродукции вируса герпеса 2-го типа и ортопоксвирусов (вирусов осповакцины и эктромелии) в культуре клеток Vero и вируса гриппа в культуре клеток MDCK. В экспериментах по защите клеток от вирусов установлено, что наибольшим противовирусным свойством обладает этанольный экстракт дождевика грушевидного, который защищает более 50 % клеток Vero от патогенного действия вирусов осповакцины и простого герпеса 2-го типа и более 75 % клеток MDCK — от цитопатического действия вируса гриппа, что может быть обусловлено большим содержанием в данном экстракте, по сравнению с другими таких БАВ, как белки и полисахариды. Исследование влияния экстрактов гастеромицетов на репродукцию вируса гриппа в культуре клеток MDCK показало, что водные и этанольные экстракты дождевика грушевидного и веселки обыкновенной оказывают ингибирующее действие на репликацию вируса гриппа А/Aichi/2/68 (H3N2) и на адсорбцию вируса гриппа птиц A/chicken/Kurgan/05/2005 (H5N1).

CpG and poly(I:C) stimulation of dendritic cells and fibroblasts limits herpes simplex virus type 1 infection in an IFNβ-dependent and -independent way

Viral activation of toll-like receptors (TLRs) on dendritic cells (DCs) leads to production of various cytokines, including antiviral type I interferons (IFNs). Synthetic ligands specific for TLRs are also able to induce the production of type I IFNs (IFNα/β) by DCs, suggesting that these ligands have potential as antiviral drugs. In this in vitro study we extensively investigated the antiviral activity of various TLR ligands. Mouse bone marrow (BM) cells were differentiated into plasmacytoid and conventional DCs (pDCs and cDCs), stimulated with various TLR ligands and tested the antiviral abilities of collected supernatants in an in vitro herpes simplex virus type 1 (HSV-1) infection model. We observed a significant IFNβ-, (but not IFNα-) dependent reduction in HSV-1 infection when a mixed pDC/cDC population was stimulated with the TLR9 ligand CpG. In the absence of pDCs, TLR stimulation resulted in less pronounced antiviral effects. The most pronounced antiviral effect was observed when both DC subsets were stimulated with poly(I:C). A similar noticeable antiviral effect was observed when fibroblasts (L929 cells) were stimulated directly with poly(I:C). These poly(I:C)-mediated antiviral effects were only partially IFNβ-mediated and probably TLR independent. These data demonstrate that TLR ligands are not only able to produce type I IFN but can indeed act as antiviral drugs. In particular poly(I:C), which exerts its antiviral effects even in the absence of DCs, may become a promising drug e.g. to prevent respiratory infections by topical intranasal application.

Otsenka effektivnosti fotodinamicheskoy terapii papillomavirusnoy infektsii pri predrake i nachal'nom rake sheyki matki

The antiviral efficiency of photodynamic therapy (PDT) was studied in 54 women infected with high-oncogenic human papillomavirus (HPV) DNA genotypes: 8 patients with moderate dysplasia (Group 1), 32 with severe dysplasia (Group 2); 14 with carcinoma in situ (Group 3). Types 16, 18 of HPV DNA were identified in virtually two thirds of cases or their combination with other high-oncogenic genotypes (31, 33, 35, 45, 58) were noted. A multiplex, quantitative, real-time polymerase chain reaction (PCR) assay was made. PDT used the photosensitizer Photosens. A follow-up lasted 3 months to 1 year. The antiviral efficiency of PDT was evaluated, by comparatively analyzing the results of the multiplex real-time PCR performed before PDT and 3, 6, and 12 months after treatment. Complete eradication of HPV was achieved in 4 women with the low clinically significant amount of virus and in 10 with a clinically significant viral load. There was a complete antiviral effect in 21 of the 36 patients with a higher viral load and a low clinically significant amount of virus in the others. Therefore, PDT has not only antitumor activity, but also a pronounced antiviral effect.

Divergent susceptibilities of human herpesvirus 6 variants to type I interferons

Two distinct human herpesvirus 6 (HHV-6) variants infect humans. HHV-6B is the etiologic agent of roseola and is associated with life-threatening neurological diseases, such as encephalitis, as well as organ transplant failure. The epidemiology and disease association for HHV-6A remain ill-defined. Specific anti-HHV-6 drugs do not exist and classic antiherpes drugs have secondary effects that are often problematic for transplant patients. Clinical trials using IFN were also performed with inconclusive results. We investigated the efficacy of type I IFN (alpha/beta) in controlling HHV-6 infection. We report that cells infected with laboratory strains and primary isolates of HHV-6B are resistant to IFN-alpha/beta antiviral actions as a result of improper IFN-stimulated gene (ISGs) expression. In contrast, HHV-6A-infected cells were responsive to IFN-alpha/beta with pronounced antiviral effects observed. Type II IFN (gamma)-signaling was unaltered in cells infected by either variant. The HHV-6B immediate-early 1 (IE1) physically interacts with STAT2 and sequestrates it to the nucleus. As a consequence, IE1B prevents the binding of ISGF3 to IFN-responsive gene promoters, resulting in ISG silencing. In comparison, HHV-6A and its associated IE1 protein displayed marginal ISG inhibitory activity relative to HHV-6B. The ISG inhibitory domain of IE1B mapped to a 41 amino acid region absent from IE1A. Transfer of this IE1B region resulted in a gain of function that conferred ISG inhibitory activity to IE1A. Our work is unique in demonstrating type I IFN signaling defects in HHV-6B-infected cells and highlights a major biological difference between HHV-6 variants.

Antiviral activity of Engystol® and Gripp-Heel®: an in-vitro assessment

BackgroundInfections with respiratory viruses can activate the innate immune response - an important host defence mechanism in the early stage of viral infection. Interferon (IFN) release, triggered by virus infection, is an important factor in establishing an antiviral state, where IFN activation occurs prior to the onset of the adaptive immune response.The two ultra-low-dose combination medications, Engystol® and Gripp-Heel®, have documented efficacy for the treatment of the respiratory infections. However, the underlying antiviral mechanisms remain elusive.MethodsIt was the goal to investigate whether Engystol® and Gripp-Heel® display antiviral activity in a prophylactic treatment protocol (2, 24 and 48 h pre-incubation) using a plaque reduction assay and whether the medications affect the release of type 1 IFN in virus-susceptible cell lines and human peripheral blood mononuclear cells (PBMCs).ResultsBoth medications demonstrate prophylactic effect against viral respiratory virus replication. However, when the incubation was continued for up to 5 days, both medications exhibited a pronounced antiviral effect which was dependent on the pre-incubation time. Moreover, in co-stimulated HeLa cells as well as in activated PBMCs Gripp-Heel® and Engystol® demonstrated an increased type 1 IFN production.ConclusionsEngystol® and Gripp-Heel® inhibited the replication of a variety of respiratory viruses. Additionally, we showed that pre-incubation affects the magnitude of the inhibitory effect differently for the various tested viruses. Both medications stimulate type 1 IFN release in different cell systems which suggests that their antiviral activity may be mediated possibly via modulation of the antiviral type 1 IFN host response.

Combinations of Cyclophilin Inhibitor NIM811 with Hepatitis C Virus NS3-4A Protease or NS5B Polymerase Inhibitors Enhance Antiviral Activity and Suppress the Emergence of Resistance

Chronic hepatitis C virus (HCV) infection remains a major global health burden while current interferon-based therapy is suboptimal. Efforts to develop more effective antiviral agents mainly focus on two viral targets: NS3-4A protease and NS5B polymerase. However, resistant mutants against these viral specific inhibitors emerge quickly both in vitro and in patients, particularly in the case of monotherapy. An alternative and complementary strategy is to target host factors such as cyclophilins that are also essential for viral replication. Future HCV therapies will most likely be combinations of multiple drugs of different mechanisms to maximize antiviral activity and to suppress the emergence of resistance. Here, the effects of combining a host cyclophilin inhibitor NIM811 with other viral specific inhibitors were investigated in vitro using HCV replicon. All of the combinations led to more pronounced antiviral effects than any single agent, with no significant increase of cytotoxicity. Moreover, the combination of NIM811 with a nucleoside (NM107) or a non-nucleoside (thiophene-2-carboxylic acid) polymerase inhibitor was synergistic, while the combination with a protease inhibitor (BILN2061) was additive. Resistant clones were selected in vitro with these inhibitors. Interestingly, it was much more difficult to develop resistance against NIM811 than viral specific inhibitors. No cross-resistance was observed among these inhibitors. Most notably, NIM811 was highly effective in blocking the emergence of resistance when used in combination with viral protease or polymerase inhibitors. Taken together, these results illustrate the significant advantages of combining inhibitors targeting both viral and host factors as key components of future HCV therapies.

Retinoic Acid Analogues Inhibit Human Herpesvirus 8 Replication

Retinoids have a pronounced antiviral effect against several viruses. In this study we aimed to investigate the effect of retinoids on human herpesvirus 8 (HHV-8). A panel of retinoic acid compounds were tested for their antiviral activity against HHV-8 in human umbilical vascular endothelial cells (HUVECs) and in a human epithelial cell line. The presence, transcription and antigen expression of HHV-8 in infected cells - in the presence or absence of retinoic acid compounds - were evaluated by PCR, reverse transcriptase PCR and immunofluorescence assays; HHV-8 viral load was determined by real-time quantitative PCR. Angiogenesis induced by HHV-8 was also assessed using Cultrex basement membrane extract. The compounds tested specifically inhibited viral promoters, during the early and late phases of infection in both cell systems tested, and resulted in up to 100-fold reduction of viral titre and release of progeny virus. The inhibition of viral replication induced by retinoids in endothelial cells, the primary target of HHV-8-driven transformation in Kaposi's Sarcoma, prevented endothelial cells from developing spindle morphology and in vitro tube formation, characteristic changes associated with HHV-8 infection and transformation. We show that retinoids inhibit HHV-8 replication and identify new retinoid compounds with a strong antiviral effect. Selective retinoids, particularly those with retinoic acid receptor agonist activity, may be good candidates for the development of antiviral drugs.

Conserved herpesvirus protein kinases

Conserved herpesviral protein kinases (CHPKs) are a group of enzymes conserved throughout all subfamilies of Herpesviridae. Members of this group are serine/threonine protein kinases that are likely to play a conserved role in viral infection by interacting with common host cellular and viral factors; however, along with a conserved role, individual kinases may have unique functions in the context of viral infection in such a way that they are only partially replaceable even by close homologues. Recent studies demonstrated that CHPKs are crucial for viral infection and suggested their involvement in regulation of numerous processes at various infection steps (primary infection, nuclear egress, tegumentation), although the mechanisms of this regulation remain unknown. Notwithstanding, recent advances in discovery of new CHPK targets, and studies of CHPK knockout phenotypes have raised their attractiveness as targets for antiviral therapy. A number of compounds have been shown to inhibit the activity of human cytomegalovirus (HCMV)-encoded UL97 protein kinase and exhibit a pronounced antiviral effect, although the same compounds are inactive against Epstein–Barr virus (EBV)-encoded protein kinase BGLF4, illustrating the fact that low homology between the members of this group complicates development of compounds targeting the whole group, and suggesting that individualized, structure-based inhibitor design will be more effective. Determination of CHPK structures will greatly facilitate this task.

Antiviral Activity and Hepatoprotection by Heme Oxygenase-1 in Hepatitis B Virus Infection

Induction of heme oxygenase-1 (HO-1) has been shown to be beneficial in immune-mediated liver damage. We now investigate the effects of HO-1 induction in models of human hepatitis B virus (HBV) infection. Adenoviral transfer of an HBV 1.3 genome into wild-type mice was used as a model for acute hepatitis B. HBV transgenic animals were used as a model for chronic HBV infection. HBV replication was assessed by HBV viremia, antigenemia, and Southern blotting, liver damage was assessed by serum alanine aminotransferase activities and histopathology of liver sections. To investigate HO-1 effects on HBV replication at a molecular level, stably HBV-transfected hepatoma cells were used. HBV gene expression, protein stability, transcription, and replication were determined. HO-1 was induced by either cobalt-protoporphyrin-IX or over expressed by adenoviral gene transfer. In the acute hepatitis B model, liver injury was reduced significantly after HO-1 induction. In addition, HO-1 showed a pronounced antiviral effect, which was confirmed in stably HBV-transfected hepatoma cells and in persistently HBV replicating transgenic mice. We showed that HO-1 induction repressed HBV replication directly in hepatocytes at a posttranscriptional step by reducing stability of HBV core protein and thus blocking refill of nuclear HBV covalently closed circular (ccc)DNA. Small interfering RNA directed against HO-1 proved that this effect depended on the expression level of HO-1. Besides its hepatoprotective effect, HO-1 showed a pronounced antiviral activity in HBV infection. Therefore, induction of HO-1 might be a novel therapeutic option for inflammatory flares of hepatitis B.

O.105 Early clinical results with CPG 10101, a new investigational antiviral TRL9 agonist being developed for treatment of subjects chronically infected with hepatitis C virus

Increasing lines of evidence suggest that DNA vaccine is of interest to fight chronic hepatitis B virus (HBV) infection. We used the Pekin duck infected by duck HBV (DHBV), closely related to the human virus, which is an attractive model allowing study of protective and therapeutic effectiveness of DNA vaccines against hepatitis B. Immunisation with a plasmid encoding the DHBV large (L) envelope protein induced a strong, specific, highly neutralising and long-lasting anti-preS humoral response in uninfected ducks. Importantly, maternal antibodies elicited by such DNA immunisation were vertically transmitted and protected progeny against viral challenge. Therapeutic immunisation of chronic DHBV-carrier ducks with this plasmid DNA led to the dramatic and sustained decrease in viral replication and even to clearance of intrahepatic viral covalently close circular DNA (cccDNA) pool in some animals. Our recent combination therapy data showed even a more pronounced antiviral effect of DNA vaccine to DHBV envelope protein when associated with antiviral drug (lamivudine) treatment. Therefore, DNA-based vaccine appears as a promising new approach for prophylaxis and therapy of hepatitis B.

Progress in DNA vaccine for prophylaxis and therapy of hepatitis B

Increasing lines of evidence suggest that DNA vaccine is of interest to fight chronic hepatitis B virus (HBV) infection. We used the Pekin duck infected by duck HBV (DHBV), closely related to the human virus, which is an attractive model allowing study of protective and therapeutic effectiveness of DNA vaccines against hepatitis B. Immunisation with a plasmid encoding the DHBV large (L) envelope protein induced a strong, specific, highly neutralising and long-lasting anti-preS humoral response in uninfected ducks. Importantly, maternal antibodies elicited by such DNA immunisation were vertically transmitted and protected progeny against viral challenge. Therapeutic immunisation of chronic DHBV-carrier ducks with this plasmid DNA led to the dramatic and sustained decrease in viral replication and even to clearance of intrahepatic viral covalently close circular DNA (cccDNA) pool in some animals. Our recent combination therapy data showed even a more pronounced antiviral effect of DNA vaccine to DHBV envelope protein when associated with antiviral drug (lamivudine) treatment. Therefore, DNA-based vaccine appears as a promising new approach for prophylaxis and therapy of hepatitis B.

The protease inhibitors

With the advent of newer antiretroviral agents for the treatment of patients with human immunodeficiency virus (HIV) infection and acquired immune deficiency syndrome (AIDS), health care providers are faced with many options to optimize their patients’ therapy. Currently, there are three groups of drugs available for the treatment of patients with HIV infection: nucleoside reverse transcriptase inhibitors (also known as nucleoside analogues), nonnucleoside reverse transcriptase inhibitors, and protease inhibitors (PIs). The preferred initial treatment regimen now consists of two nucleoside analogues and a PI. Protease inhibitors cause profound and sustained suppression of viral replication, increase time to first AIDS-defining illness, and reduce mortality. Each of the available PIs have distinct pharmacokinetic and metabolic properties that result in different dosing regimens and potential for interactions with food and other drugs. Patients with HIV infection typically receive several drugs; therefore, convenience of administration, optimal side-effect profile, and cost of the agents must also be considered along with the potential for drug interactions. A growing proportion of HIV patients worldwide are women. HIV-infected pregnant women should be offered antiretroviral prophylaxis to prevent perinatal HIV transmission as well as to optimize their own health. Zidovudine (ZDV) treatment has been the standard antiretroviral treatment during pregnancy; however, recent data has shown that combination regimens produce a more pronounced antiviral effect and may be more effective than ZDV monotherapy in preventing perinatal HIV transmission.

Antiviral chemotherapy.

Over the last few years, several new antiviral agents have been added to the chemotherapeutic armamentarium. This review discusses advances in the treatment of HIV disease in children and adults. More pronounced antiviral effects have been achieved through the study of new agents such as the protease inhibitors as well as through a better understanding of previously approved drugs, such as reverse transcriptase inhibitors.