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1.
Int J Gen Med ; 17: 419-428, 2024.
Article in English | MEDLINE | ID: mdl-38333020

ABSTRACT

Purpose: Nonpharmacological, barrier-forming nasal sprays are used to manage symptoms of allergic rhinitis. We aim to evaluate the safety and effectiveness of Callergin (investigational product, IP), a nasal spray containing barrier-forming iota-carrageenan, in the treatment of allergic rhinitis (AR). Methods: In this randomized, controlled, crossover trial, adults with grass pollen allergy underwent a treatment sequence with IP, VisAlpin (comparator product, CP), and no treatment in random order. Treatment blocks consisted in prophylactic administration of the assigned treatment or no treatment, followed by a 3-hr allergen exposure, and were separated by a washout period of 7 days. Primary endpoint was a mean change from baseline in "Total Nasal Symptom Score" (TNSS, sum of rhinorrhea, itching, sneezing, and congestion scores) over 3 hr, recorded every 15 min during the challenge period. Results: A total of 42 participants underwent randomization. Exposure to grass pollen for 3 hr induced a notable TNSS increase from baseline in all participants at all times. Mean TNSS change from baseline over 3 hr was lower when participants received IP compared to no treatment, although the difference did not reach statistical significance (untreated 6.96 ± 2.30; IP 6.59 ± 1.93; difference 0.37 points [95% CI (confidence interval) -0.17 to 0.91]; p=0.170). In a post-hoc analysis, mean TNSS at 3 hr was significantly reduced after IP treatment compared to no treatment (untreated 8.29 ± 2.64; IP 7.70 ± 2.56; difference 0.60 points [95% CI -0.10 to 1.29] p=0.028). While all individual nasal symptoms contributed to this effect, rhinorrhea (p=0.013) and congestion (p=0.076) contributed most. Consistently, nasal secretion weight was slightly reduced with IP treatment (p=0.119). IP was safe and well-tolerated, with similar incidence of adverse events across treatment groups. Conclusion: Prophylactic treatment with the iota-carrageenan nasal spray IP is safe, well-tolerated, and alleviates nasal allergy symptoms in adults with grass pollen-induced AR. Trial Registration: NCT04531358.

2.
Viruses ; 14(7)2022 06 27.
Article in English | MEDLINE | ID: mdl-35891385

ABSTRACT

The ubiquitin proteasome system (UPS), particularly its deubiquitinating enzymes (DUBs), play a key role in the replication cycle of coronaviruses. The SARS-CoV-2 papain-like protease (Plpro) is known to process the viral polyproteins to form the replicase transcriptase complex and to counteract the host viral response. Recently, it was shown that this viral protease can also act as a deubiquitinating enzyme. In this study, we demonstrate that certain DUB-Inhibitors (DIs) interfere with SARS-CoV-2 replication. The DIs PR-619 and HBX41108 restrict SARS-CoV-2 in both Vero B4 and human Calu-3 lung cells where cells were infected with a Multiplicity of Infection (MOI) of 0.02. An in vitro protease assay using recombinant Plpro and Amido-4-methylcoumarin (AMC)-conjugated substrate revealed that PR-619 and HBX41108 are able to block the protease at concentrations where the interventions restricted virus replication. In contrast, DIs that do not inhibit Plpro had no influence on virus replication, which indicated that the protease might be at least one major target. Future vertical studies that would gain more insights into the mechanisms of how DUBs effect the replication of SARS-CoV-2 will further validate them as a potential therapeutic target.


Subject(s)
COVID-19 , SARS-CoV-2 , Coronavirus Papain-Like Proteases , Deubiquitinating Enzymes , Humans , Papain , Peptide Hydrolases , Protease Inhibitors/pharmacology , Virus Replication
3.
J Prev (2022) ; 43(1): 5-23, 2022 02.
Article in English | MEDLINE | ID: mdl-34962632

ABSTRACT

Body ideals conveyed by the media and by body comparisons often result in body dissatisfaction, which can cause risky health behaviours and eating disorders, especially in adolescents. We conducted a meta-analytic review of existing school-based interventions designed to enhance media literacy in order to reduce body dissatisfaction and to promote a positive body image. We included controlled trials examining children and adolescents from grade five to nine (age 10-15 years) after a manual search and a comprehensive literature search using PsycINFO, Medline, Web of Science, and CENTRAL. We computed average weighted effect sizes (Hedges' g) with the help of a random effects model and identified seventeen different programme evaluations with 7392 participants. We found a significantly larger effect on positive body image and media literacy in the intervention compared to control groups. However, heterogeneity was substantial for both outcomes. Results suggest that media literacy interventions have the potential to improve media literacy and reduce body dissatisfaction. Interventions that worked with the principle of induction of cognitive dissonance were the most effective.


Subject(s)
Body Dissatisfaction , Feeding and Eating Disorders , Adolescent , Body Image/psychology , Child , Feeding and Eating Disorders/prevention & control , Humans , Literacy , Schools
4.
Int J Mol Sci ; 22(24)2021 Dec 08.
Article in English | MEDLINE | ID: mdl-34947999

ABSTRACT

The COVID-19 pandemic continues to spread around the world and remains a major public health threat. Vaccine inefficiency, vaccination breakthroughs and lack of supply, especially in developing countries, as well as the fact that a non-negligible part of the population either refuse vaccination or cannot be vaccinated due to age, pre-existing illness or non-response to existing vaccines intensify this issue. This might also contribute to the emergence of new variants, being more efficiently transmitted, more virulent and more capable of escaping naturally acquired and vaccine-induced immunity. Hence, the need of effective and viable prevention options to reduce viral transmission is of outmost importance. In this study, we investigated the antiviral effect of iota-, lambda- and kappa-carrageenan, sulfated polysaccharides extracted from red seaweed, on SARS-CoV-2 Wuhan type and the spreading variants of concern (VOCs) Alpha, Beta, Gamma and Delta. Carrageenans as part of broadly used nasal and mouth sprays as well as lozenges have the potential of first line defense to inhibit the infection and transmission of SARS-CoV-2. Here, we demonstrate by using a SARS-CoV-2 spike pseudotyped lentivirus particles (SSPL) system and patient-isolated SARS-CoV-2 VOCs to infect transgenic A549ACE2/TMPRSS2 and Calu-3 human lung cells that all three carrageenan types exert antiviral activity. Iota-carrageenan exhibits antiviral activity with comparable IC50 values against the SARS-CoV-2 Wuhan type and the VOCs. Altogether, these results indicate that iota-carrageenan might be effective for prophylaxis and treatment of SARS-CoV-2 infections independent of the present and potentially future variants.


Subject(s)
COVID-19 Drug Treatment , COVID-19/virology , Carrageenan/pharmacology , SARS-CoV-2/drug effects , Virus Replication/drug effects , Animals , Antiviral Agents/pharmacology , COVID-19/epidemiology , COVID-19/immunology , COVID-19 Vaccines/pharmacology , Chlorocebus aethiops , HEK293 Cells , Humans , Pandemics , Polysaccharides/pharmacology , SARS-CoV-2/metabolism , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/immunology , Vaccination/methods , Vero Cells
5.
Int J Mol Sci ; 22(19)2021 Sep 22.
Article in English | MEDLINE | ID: mdl-34638545

ABSTRACT

Even in the face of global vaccination campaigns, there is still an urgent need for effective antivirals against SARS-CoV-2 and its rapidly spreading variants. Several natural compounds show potential as antiviral substances and have the advantages of broad availabilities and large therapeutic windows. Here, we report that lectin from Triticum vulgaris (Wheat Germ Agglutinin) displays antiviral activity against SARS-CoV-2 and its major Variants of Concern (VoC), Alpha and Beta. In Vero B4 cells, WGA potently inhibits SARS-CoV-2 infection with an IC50 of <10 ng/mL. WGA is effective upon preincubation with the virus or when added during infection. Pull-down assays demonstrate direct binding of WGA to SARS-CoV-2, further strengthening the hypothesis that inhibition of viral entry by neutralizing free virions might be the mode of action behind its antiviral effect. Furthermore, WGA exhibits antiviral activity against human coronavirus OC43, but not against other non-coronaviruses causing respiratory tract infections. Finally, WGA inhibits infection of the lung cell line Calu-3 with wild type and VoC viruses with comparable IC50 values. Altogether, our data indicate that topical administration of WGA might be effective for prophylaxis or treatment of SARS-CoV-2 infections.


Subject(s)
Antiviral Agents/pharmacology , COVID-19 Drug Treatment , SARS-CoV-2/drug effects , Wheat Germ Agglutinins/pharmacology , Animals , Antiviral Agents/chemistry , COVID-19/virology , Chlorocebus aethiops , Humans , SARS-CoV-2/physiology , Triticum/chemistry , Vero Cells , Virus Replication/drug effects , Wheat Germ Agglutinins/chemistry
6.
Int J Gen Med ; 14: 5241-5249, 2021.
Article in English | MEDLINE | ID: mdl-34526804

ABSTRACT

PURPOSE: The aim of this study was to investigate whether sucking of an iota-carrageenan containing lozenge releases sufficient iota-carrageenan into the saliva of healthy subjects to neutralize representatives of the most common respiratory virus families causing common cold and SARS-CoV-2. PATIENTS AND METHODS: In this monocentric, open label, prospective clinical trial, 31 healthy subjects were included to suck a commercially available iota-carrageenan containing lozenge. Saliva samples from 27 subjects were used for ex vivo efficacy analysis. The study's primary objective was to assess if the mean iota-carrageenan concentration of the saliva samples exceeded 5 µg/mL, which is the concentration known to reduce replication of human rhinovirus (hRV) 1a and 8 by 90%. The iota-carrageenan concentration of the saliva samples was analyzed by UV-Vis spectroscopy. The antiviral effectiveness of the individual saliva samples was determined in vitro against a panel of respiratory viruses including hRV1a, hRV8, human coronavirus OC43, influenza virus A H1N1pdm09, coxsackievirus A10, parainfluenza virus 3 and SARS-CoV-2 using standard virological assays. RESULTS: The mean iota-carrageenan concentration detected in the saliva exceeds the concentration needed to inhibit 90% of hRV1a and hRV8 replication by 134-fold (95% CI 116.3-160.8-fold; p < 0.001). Thus, the study met the primary endpoint. Furthermore, the iota-carrageenan saliva concentration was 60 to 30,351-fold higher than needed to reduce viral replication/binding of all tested viruses by at least 90% (p < 0.001). The effect was most pronounced in hCoV OC43; in case of SARS-CoV-2, the IC90 was exceeded by 121-fold (p < 0.001). CONCLUSION: Sucking an iota-carrageenan containing lozenge releases sufficient iota-carrageenan to neutralize and inactivate the most abundant respiratory viruses as well as pandemic SARS-CoV-2. The lozenges are therefore an appropriate measure to reduce the viral load at the site of infection, hereby presumably limiting transmission within a population as well as translocation to the lower respiratory tract. TRIAL REGISTRATION: NCT04533906.

7.
PLoS One ; 16(2): e0237480, 2021.
Article in English | MEDLINE | ID: mdl-33596218

ABSTRACT

In the absence of a vaccine and other effective prophylactic or therapeutic countermeasures the severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) remains a significant public health threat. Attachment and entry of coronaviruses including SARS-CoV-2 is mainly mediated by the spike glycoprotein. Here, we show that iota-carrageenan can inhibit the cell entry of the SARS-CoV-2 spike pseudotyped lentivirus in a dose dependent manner. SARS-CoV-2 spike pseudotyped lentivirus particles were efficiently neutralized with an IC50 value of 2.6 µg/ml iota-carrageenan. Experiments with patient isolated wild type SARS-CoV-2 virus showed an inhibition of replication in a similar range. In vitro data on iota-carrageenan against various Rhino- and endemic Coronaviruses showed similar IC50 values and translated readily into clinical effectiveness when a nasal spray containing iota-carrageenan demonstrated a reduction of severity and duration of symptoms of common cold caused by various respiratory viruses. Accordingly, our in vitro data on SARS-CoV-2 spike pseudotyped lentivirus and replication competent SARS-CoV-2 suggest that administration of iota-carrageenan may be an effective and safe prophylaxis or treatment for SARS-CoV-2 infections.


Subject(s)
COVID-19/virology , Carrageenan/pharmacology , SARS-CoV-2/drug effects , Virus Replication/drug effects , Animals , Antibodies, Viral/immunology , Antiviral Agents/pharmacology , COVID-19/immunology , COVID-19/metabolism , Chlorocebus aethiops , HEK293 Cells , Humans , Lentivirus/metabolism , Middle Aged , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells , Virus Internalization/drug effects , COVID-19 Drug Treatment
8.
Pharmaceutics ; 12(9)2020 Sep 05.
Article in English | MEDLINE | ID: mdl-32899549

ABSTRACT

Due to fast nasal mucociliary clearance, only the dissolved drug content can effectively permeate the mucosa and be pharmaceutically active after intranasal application of suspensions. Therefore, the aim of this study was to increase the budesonide concentration in solution of a nasal spray formulation. Budesonide, a highly water-insoluble corticosteroid, was successfully solubilized using a micellar formulation comprising escin, propylene glycol and dexpanthenol in an aqueous buffered environment ("Budesolv"). A formulation based on this micellar system was well-tolerated in the nasal cavity as shown in a good laboratory practice (GLP) local tolerance study in rabbits. Ex vivo permeation studies into porcine nasal mucosa revealed a faster and more efficient absorption. Budesolv with 300 µg/mL solubilized budesonide resulted in a budesonide concentration of 42 µg/g tissue after only 15 min incubation. In comparison, incubation with the marketed product Rhinocort® aqua 64 (1.28 mg/mL budesonide as suspension) led to 15 µg/g tissue. The in vivo tumor-necrosis-factor (TNF)-α secretion in an acute lung inflammation mouse model was significantly reduced (p < 0.001) following a prophylactic treatment with Budesolv compared to Rhinocort® aqua 64. Successful treatment 15 min after the challenge was only possible with Budesolv (40% reduction of TNF-α, p = 0.0012) suggesting a faster onset of action. The data reveal that solubilization based on saponin micelles presents an opportunity for the development of products containing hardly soluble substances that result in a faster onset and a better topical treatment effect.

9.
Psychother Psychosom Med Psychol ; 70(9-10): 396-404, 2020 Oct.
Article in German | MEDLINE | ID: mdl-32069511

ABSTRACT

Social participation is politically as well as socially and psychologically relevant for the coexistence of people in our society and the well-being of the individual. In light of the German Federal Participation Act and the partial equalization of the terms "(Social) Participation" and "Inclusion", social participation in recent years has frequently been restricted to people with disabilities with regard to the "International Classification of Functioning, Disability and Health (ICF)" of the World Health Organization and the UN Convention on the Rights of Persons with Disabilities. The question of participation, however, affects all people and is not only dependent on the degree of functional capacity or disability, but also on social inclusion, financial possibilities, regional affiliation, education, self-esteem and is correlated with health. In the present study, a new short scale of 5 items (KsT-5) for measuring the aspects "belonging", "self-efficacy", "need for recognition", "self-esteem" and "integration in the social environment" was tested on a German representative general population sample (N=2531) with regard to their psychometric quality criteria. It showed a good fit with a one-factor solution, a satisfactory internal consistency of Cronbach's α=0,73 and McDonald's ω=0,73 as well as good convergent validity over positive correlations with self-esteem and psychological as well as physical health. This study provides norm values of the new KsT-5 stratified according to gender and age as a prerequisite for use in future studies.


Subject(s)
Social Participation/psychology , Adolescent , Adult , Aged , Disability Evaluation , Disabled Persons/psychology , Factor Analysis, Statistical , Female , Germany , Humans , Male , Middle Aged , Psychometrics , Quality of Life , Reference Standards , Reproducibility of Results , Self Concept , Self Efficacy , Young Adult
10.
Int J Gen Med ; 11: 275-283, 2018.
Article in English | MEDLINE | ID: mdl-30013382

ABSTRACT

INTRODUCTION: Xylometazoline hydrochloride (HCl) is a nasal decongestant that causes vasoconstriction in the nasal submucosa. It has been used for more than 50 years for the treatment of nasal congestion caused by rhinitis/sinusitis. Iota-carrageenan is effective against a broad variety of respiratory viruses, which are the most common cause of infections of the upper respiratory tract. Therefore, it is used as the active component in the antiviral nasal spray Coldamaris prophylactic (1.2 mg/mL iota-carrageenan in 0.5% NaCl) and other medical device nasal sprays that are approved and marketed in the EU. Recently, we developed a nasal spray formulation containing both xylometazoline HCl (0.05%) and iota-carrageenan (0.12%) that provides decongestion and antiviral protection of the nasal mucosa at the same time. RESULTS: A set of in vitro experiments revealed that the vasoconstrictive properties of xylometazoline HCl and the antiviral effectiveness of iota-carrageenan against human rhinovirus (hRV) 1a, hRV8 and human coronavirus OC43 were maintained in the formulation containing these two compounds. Permeation experiments using bovine nasal mucosa showed that iota-carrageenan had no significant influence on the permeation of xylometazoline HCl. Finally, in the local tolerance and toxicity study, it was shown that the formulation was well tolerated at the application site with no occurrence of erythema or edema in the nostrils of all rabbits or any signs of toxicity in any of the organs and tissues inspected. CONCLUSION: Investigations on compatibility of xylometazoline HCl and iota-carrageenan demonstrated that the substances do not influence each other, allowing both to fulfill their known specific clinical efficacy (xylometazoline HCl) and effectiveness (iota-carrageenan).

11.
Int J Gen Med ; 10: 53-60, 2017.
Article in English | MEDLINE | ID: mdl-28280379

ABSTRACT

Up to 80% of sore throats are caused by viruses. Several over the counter products are available which provide symptomatic, not causal relief. For such lozenges, containing the antiseptics and local anesthetics amylmetacresol (AMC) and 2,4-dichlorobenzyl alcohol (DCBA) or hexylresorcinol (HR), recently an additional virucidal effect was published. Therefore, we tested a set of Strepsils® lozenges, containing either HR (Max [#2]) or AMC/DCBA (Original [#3], Extra Strong [#4], Warm [#5], Orange and Vitamin C [#6], Sugar free Lemon [#7], Children/Strawberry [#8] and Soothing Honey and Lemon [#9]) for their antiviral efficiency against representatives of respiratory viruses known to cause sore throat: human rhinovirus (HRV) 1a, HRV8, influenza virus A H1N1n, Coxsackievirus A10, and human coronavirus (hCoV) OC43. The lozenges were tested head to head with Coldamaris® lozenges (#1), which contain the patented antiviral iota-carrageenan. None of the tested AMC/DCBA or HR containing lozenges shows any antiviral effectiveness against HRV8 at the tested concentrations, whereas all are moderately active against HRV1a. Only lozenge #5 shows any activity against hCoV OC43 and Coxsackievirus A10 at the tested concentrations. Similarly, only lozenge #3 is moderately active against influenza A H1N1n virus. The data indicates that neither the isolated effect of the active ingredients nor the pH but rather one or more of the excipients of the specific formulations are responsible for the antiviral effect of some of the AMC/DCBA or HR containing lozenges. In contrast, carrageenan-containing lozenges are highly active against all viruses tested. In another experiment, we showed that binding and inactivation of virus particles by iota-carrageenan are fast and highly effective. During the residence time of the lozenge in the mouth, the viral titer is reduced by 85% and 91% for influenza A virus and hCoV OC43, respectively. Carrageenan-containing lozenges are, therefore, suitable as causative therapy against viral infections of the throat.

12.
PLoS One ; 10(6): e0128794, 2015.
Article in English | MEDLINE | ID: mdl-26053018

ABSTRACT

BACKGROUND: Carrageenan is a clinically proven and marketed compound for the treatment of viral upper respiratory tract infections. As infections caused by influenza virus are often accompanied by infections with other respiratory viruses the combination of a specific anti-influenza compound with the broadly active antiviral polymer has huge potential for the treatment of respiratory infections. Thus, the combination of the specific anti-influenza drug Zanamivir together with carrageenan in a formulation suitable for intranasal application was evaluated in-vitro and in-vivo. PRINCIPAL FINDINGS: We show in-vitro that carrageenan and Zanamivir act synergistically against several influenza A virus strains (H1N1(09)pdm, H3N2, H5N1, H7N7). Moreover, we demonstrate in a lethal influenza model with a low pathogenic H7N7 virus (HA closely related to the avian influenza A(H7N9) virus) and a H1N1(09)pdm influenza virus in C57BL/6 mice that the combined use of both compounds significantly increases survival of infected animals in comparison with both mono-therapies or placebo. Remarkably, this benefit is maintained even when the treatment starts up to 72 hours post infection. CONCLUSION: A nasal spray containing carrageenan and Zanamivir should therefore be tested for prevention and treatment of uncomplicated influenza in clinical trials.


Subject(s)
Carrageenan/administration & dosage , Carrageenan/therapeutic use , Influenza A virus/drug effects , Orthomyxoviridae Infections/drug therapy , Zanamivir/administration & dosage , Zanamivir/therapeutic use , Administration, Intranasal , Animals , Antiviral Agents/therapeutic use , Carrageenan/pharmacology , Disease Models, Animal , Dogs , Humans , Influenza A Virus, H7N7 Subtype/drug effects , Inhibitory Concentration 50 , Madin Darby Canine Kidney Cells , Mice , Orthomyxoviridae Infections/prevention & control , Orthomyxoviridae Infections/virology , Treatment Outcome , Zanamivir/pharmacology
13.
Virus Res ; 168(1-2): 48-55, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22727684

ABSTRACT

The replication of tick-borne encephalitis virus (TBEV), like that of all flaviviruses, is absolutely dependent on proteolytic processing. Production of the mature proteins C and prM from their common precursor requires the activity of the viral NS2B/3 protease (NS2B/3(pro)) at the C-terminus of protein C and the host signal peptidase I (SPaseI) at the N-terminus of protein prM. Recently, we have shown in cell culture that the cleavage of protein C and the subsequent production of TBEV particles can be made dependent on the activity of the foot-and-mouth disease virus 3C protease, but not on the activity of the HIV-1 protease (HIV1(pro)) (Schrauf et al., 2012). To investigate this failure, we developed an in vitro cleavage assay to assess the two cleavage reactions performed on the C-prM precursor. Accordingly, a recombinant modular NS2B/3(pro), consisting of the protease domain of NS3 linked to the core-domain of cofactor NS2B, was expressed in E. coli and purified to homogeneity. This enzyme could cleave a C-prM protein synthesised in rabbit reticulocyte lysates. However, cleavage was only specific when protein synthesis was performed in the presence of canine pancreatic microsomal membranes and required the prevention of signal peptidase I (SPaseI) activity by lengthening the h-region of the signal peptide. The presence of membranes allowed the concentration of NS2B/3(pro) used to be reduced by 10-20 fold. Substitution of the NS2B/3(pro) cleavage motif in C-prM by a HIV-1(pro) motif inhibited NS2B/3(pro) processing in the presence of microsomal membranes but allowed cleavage by HIV-1(pro) at the C-prM junction. This system shows that processing at the C-terminus of protein C by the TBEV NS2B/3(pro) is highly membrane dependent and will allow the examination of how the membrane topology of protein C affects both SPaseI and NS2B/3(pro) processing.


Subject(s)
Capsid Proteins/metabolism , Dog Diseases/virology , Encephalitis Viruses, Tick-Borne/enzymology , Encephalitis, Tick-Borne/veterinary , Intracellular Membranes/virology , Viral Envelope Proteins/metabolism , Viral Nonstructural Proteins/metabolism , Amino Acid Sequence , Animals , Capsid Proteins/chemistry , Capsid Proteins/genetics , Dog Diseases/metabolism , Dogs , Encephalitis Viruses, Tick-Borne/chemistry , Encephalitis Viruses, Tick-Borne/genetics , Encephalitis Viruses, Tick-Borne/metabolism , Encephalitis, Tick-Borne/metabolism , Encephalitis, Tick-Borne/virology , Intracellular Membranes/metabolism , Microsomes/metabolism , Microsomes/virology , Molecular Sequence Data , Proteolysis , RNA Helicases/chemistry , RNA Helicases/genetics , RNA Helicases/metabolism , Sequence Alignment , Serine Endopeptidases/chemistry , Serine Endopeptidases/genetics , Serine Endopeptidases/metabolism , Viral Envelope Proteins/chemistry , Viral Envelope Proteins/genetics , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/genetics
14.
J Gen Virol ; 93(Pt 3): 504-515, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22131310

ABSTRACT

Mature protein C of tick-borne encephalitis virus (TBEV) is cleaved from the polyprotein precursor by the viral NS2B/3 protease (NS2B/3(pro)). We showed previously that replacement of the NS2B/3(pro) cleavage site at the C terminus of protein C by the foot-and-mouth disease virus (FMDV) 2A StopGo sequence leads to the production of infectious virions. Here, we show that infectious virions can also be produced from a TBEV mutant bearing an inactivated 2A sequence through the expression of the FMDV 3C protease (3C(pro)) either in cis or in trans (from a TBEV replicon). Cleavage at the C terminus of protein C depended on the catalytic activity of 3C(pro) as well as on the presence of an optimized 3C(pro) cleavage site. Passage of the TBEV mutants bearing a 3C(pro) cleavage site either in the absence of 3C(pro) or in the presence of a catalytically inactive 3C(pro) led to the appearance of revertants in which protein C cleavage by NS2B/3(pro) had been regained. In three different revertants, a cleavage site for NS2B/3(pro), namely RR*C, was now present, leading to an elongated protein C. Furthermore, two revertants acquired additional mutations in the C terminus of protein C, eliminating two basic residues. Although these latter mutants showed wild-type levels of early RNA synthesis, their foci were smaller and an accumulation of protein C in the cytoplasm was observed. These findings suggest a role of the positive charge of the C terminus of protein C for budding of the nucleocapsid and further support the notion that TBEV protein C is a multifunctional protein.


Subject(s)
Cysteine Endopeptidases/metabolism , Encephalitis Viruses, Tick-Borne/physiology , Foot-and-Mouth Disease Virus/enzymology , Viral Nonstructural Proteins/metabolism , Viral Proteins/metabolism , Virus Replication , 3C Viral Proteases , Cysteine Endopeptidases/genetics , Encephalitis Viruses, Tick-Borne/genetics , Mutation , RNA Helicases/genetics , RNA Helicases/metabolism , Recombination, Genetic , Serine Endopeptidases/genetics , Serine Endopeptidases/metabolism , Viral Nonstructural Proteins/genetics , Viral Proteins/genetics
15.
J Virol ; 79(16): 10672-7, 2005 Aug.
Article in English | MEDLINE | ID: mdl-16051859

ABSTRACT

Engineering of the influenza A virus NS1 protein became an attractive approach to the development of influenza vaccine vectors since it can tolerate large inserts of foreign proteins. However, influenza virus vectors expressing long foreign sequences from the NS1 open reading frame (ORF) are usually replication deficient in animals due to the abrogation of their NS1 protein function. In this study, we describe a bicistronic expression strategy based on the insertion of an overlapping UAAUG stop-start codon cassette into the NS gene, allowing the reinitiation of translation of a foreign sequence. Although the expression level of green fluorescent protein (GFP) from the newly created reading frame was significantly lower than that obtained previously from an influenza virus vector expressing GFP from the NS1 ORF, the bicistronic vector appeared to be replication competent in mice and showed outstanding genetic stability. All viral isolates derived from mouse lungs at 10 days postinfection were still capable of expressing GFP in infected cells. Utilizing this bicistronic approach, we constructed another recombinant influenza virus, allowing the secretion of biologically active human interleukin-2 (IL-2). Although this virus also replicated to high titers in mouse lungs, it did not display any mortality rate in infected animals, in contrast to control viruses. Moreover, the IL-2-expressing virus showed an enhanced CD8+ response to viral antigens in mice after a single intranasal immunization. These results indicate that influenza viruses could be engineered for the expression of biologically active molecules such as cytokines for immune modulation purposes.


Subject(s)
Genetic Vectors/genetics , Influenza A virus/genetics , Interleukin-2/genetics , Viral Nonstructural Proteins/genetics , Animals , CD8-Positive T-Lymphocytes/immunology , Cell Line , Humans , Immunoglobulin G/blood , Mice , Recombination, Genetic
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