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2.
Protein & Cell ; (12): 723-739, 2020.
Article in English | WPRIM | ID: wpr-827018

ABSTRACT

Emerging and re-emerging RNA viruses occasionally cause epidemics and pandemics worldwide, such as the on-going outbreak of the novel coronavirus SARS-CoV-2. Herein, we identified two potent inhibitors of human DHODH, S312 and S416, with favorable drug-likeness and pharmacokinetic profiles, which all showed broad-spectrum antiviral effects against various RNA viruses, including influenza A virus, Zika virus, Ebola virus, and particularly against SARS-CoV-2. Notably, S416 is reported to be the most potent inhibitor so far with an EC of 17 nmol/L and an SI value of 10,505.88 in infected cells. Our results are the first to validate that DHODH is an attractive host target through high antiviral efficacy in vivo and low virus replication in DHODH knock-out cells. This work demonstrates that both S312/S416 and old drugs (Leflunomide/Teriflunomide) with dual actions of antiviral and immuno-regulation may have clinical potentials to cure SARS-CoV-2 or other RNA viruses circulating worldwide, no matter such viruses are mutated or not.


Subject(s)
Animals , Antiviral Agents , Pharmacology , Therapeutic Uses , Betacoronavirus , Physiology , Binding Sites , Cell Line , Coronavirus Infections , Drug Therapy , Virology , Crotonates , Pharmacology , Cytokine Release Syndrome , Drug Therapy , Drug Evaluation, Preclinical , Gene Knockout Techniques , Humans , Influenza A virus , Leflunomide , Pharmacology , Mice , Mice, Inbred BALB C , Orthomyxoviridae Infections , Drug Therapy , Oseltamivir , Therapeutic Uses , Oxidoreductases , Metabolism , Pandemics , Pneumonia, Viral , Drug Therapy , Virology , Protein Binding , Pyrimidines , RNA Viruses , Physiology , Structure-Activity Relationship , Toluidines , Pharmacology , Ubiquinone , Metabolism , Virus Replication
3.
Protein & Cell ; (12): 723-739, 2020.
Article in English | WPRIM | ID: wpr-828747

ABSTRACT

Emerging and re-emerging RNA viruses occasionally cause epidemics and pandemics worldwide, such as the on-going outbreak of the novel coronavirus SARS-CoV-2. Herein, we identified two potent inhibitors of human DHODH, S312 and S416, with favorable drug-likeness and pharmacokinetic profiles, which all showed broad-spectrum antiviral effects against various RNA viruses, including influenza A virus, Zika virus, Ebola virus, and particularly against SARS-CoV-2. Notably, S416 is reported to be the most potent inhibitor so far with an EC of 17 nmol/L and an SI value of 10,505.88 in infected cells. Our results are the first to validate that DHODH is an attractive host target through high antiviral efficacy in vivo and low virus replication in DHODH knock-out cells. This work demonstrates that both S312/S416 and old drugs (Leflunomide/Teriflunomide) with dual actions of antiviral and immuno-regulation may have clinical potentials to cure SARS-CoV-2 or other RNA viruses circulating worldwide, no matter such viruses are mutated or not.


Subject(s)
Animals , Antiviral Agents , Pharmacology , Therapeutic Uses , Betacoronavirus , Physiology , Binding Sites , Cell Line , Coronavirus Infections , Drug Therapy , Virology , Crotonates , Pharmacology , Cytokine Release Syndrome , Drug Therapy , Drug Evaluation, Preclinical , Gene Knockout Techniques , Humans , Influenza A virus , Leflunomide , Pharmacology , Mice , Mice, Inbred BALB C , Orthomyxoviridae Infections , Drug Therapy , Oseltamivir , Therapeutic Uses , Oxidoreductases , Metabolism , Pandemics , Pneumonia, Viral , Drug Therapy , Virology , Protein Binding , Pyrimidines , RNA Viruses , Physiology , Structure-Activity Relationship , Toluidines , Pharmacology , Ubiquinone , Metabolism , Virus Replication
4.
Protein & Cell ; (12): 723-739, 2020.
Article in English | WPRIM | ID: wpr-828583

ABSTRACT

Emerging and re-emerging RNA viruses occasionally cause epidemics and pandemics worldwide, such as the on-going outbreak of the novel coronavirus SARS-CoV-2. Herein, we identified two potent inhibitors of human DHODH, S312 and S416, with favorable drug-likeness and pharmacokinetic profiles, which all showed broad-spectrum antiviral effects against various RNA viruses, including influenza A virus, Zika virus, Ebola virus, and particularly against SARS-CoV-2. Notably, S416 is reported to be the most potent inhibitor so far with an EC of 17 nmol/L and an SI value of 10,505.88 in infected cells. Our results are the first to validate that DHODH is an attractive host target through high antiviral efficacy in vivo and low virus replication in DHODH knock-out cells. This work demonstrates that both S312/S416 and old drugs (Leflunomide/Teriflunomide) with dual actions of antiviral and immuno-regulation may have clinical potentials to cure SARS-CoV-2 or other RNA viruses circulating worldwide, no matter such viruses are mutated or not.


Subject(s)
Animals , Antiviral Agents , Pharmacology , Therapeutic Uses , Betacoronavirus , Physiology , Binding Sites , Cell Line , Coronavirus Infections , Drug Therapy , Virology , Crotonates , Pharmacology , Cytokine Release Syndrome , Drug Therapy , Drug Evaluation, Preclinical , Gene Knockout Techniques , Humans , Influenza A virus , Leflunomide , Pharmacology , Mice , Mice, Inbred BALB C , Orthomyxoviridae Infections , Drug Therapy , Oseltamivir , Therapeutic Uses , Oxidoreductases , Metabolism , Pandemics , Pneumonia, Viral , Drug Therapy , Virology , Protein Binding , Pyrimidines , RNA Viruses , Physiology , Structure-Activity Relationship , Toluidines , Pharmacology , Ubiquinone , Metabolism , Virus Replication
5.
J. bras. nefrol ; 41(4): 539-549, Out.-Dec. 2019. tab, graf
Article in English | LILACS | ID: biblio-1056608

ABSTRACT

Abstract According to data from the last census of the Brazilian Society of Nephrology (SBN), the prevalence of hepatitis C virus (HCV) in Brazilian hemodialysis units (HU) is 3.3%, about three times higher than what is reported for the Brazilian general population. Often, professionals working in HU are faced with clinical situations that require rapid HCV diagnosis in order to avoid horizontal transmission within the units. On the other hand, thanks to the development of new antiviral drugs, the cure of patients with HCV, both in the general population and in patients with chronic kidney disease and the disease eradication, appear to be very feasible objectives to be achieved in the near future . In this scenario, SBN and the Brazilian Society of Hepatology present in this review article a proposal to approach HCV within HUs.


Resumo De acordo com os dados do último censo da Sociedade Brasileira de Nefrologia (SBN), a prevalência de portadores do vírus da hepatite C (HCV) nas unidades de hemodiálise (UH) no Brasil é de 3,3%, cerca de três vezes maior do que é observado na população geral brasileira. Muitas vezes, os profissionais que trabalham nas UH deparam-se com situações clínicas que demandam rápido diagnóstico do HCV, a fim de evitar uma transmissão horizontal dentro das unidades. Por outro lado, a cura dos pacientes portadores do HCV, tanto na população geral como na portadora de doença renal crônica e a erradicação da doença, em virtude do desenvolvimento de novas drogas antivirais, parecem ser objetivos bastante factíveis, a ser alcançados em futuro próximo. Nesse cenário, a SBN e a Sociedade Brasileira de Hepatologia apresentam neste artigo de revisão uma proposta de abordagem do HCV dentro das UH.


Subject(s)
Humans , Renal Dialysis/statistics & numerical data , Hepatitis C/epidemiology , Disease Transmission, Infectious/prevention & control , Renal Insufficiency, Chronic/therapy , Antiviral Agents/therapeutic use , RNA Viruses/genetics , Brazil/epidemiology , Cross Infection/transmission , Prevalence , Hepatitis C/diagnosis , Hepatitis C/drug therapy , Hepacivirus/drug effects , Hepacivirus/genetics , Glomerular Filtration Rate/physiology , Nephrology/organization & administration , Nephrology/statistics & numerical data
6.
Rev. chil. infectol ; 36(1): 26-31, feb. 2019. tab, graf
Article in Spanish | LILACS | ID: biblio-1003653

ABSTRACT

Resumen Introducción: La temprana detección viral en infecciones respiratorias agudas (IRA) es esencial para establecer una terapia apropiada y prevenir el contagio intrahospitalario. Objetivo: Comparar la eficacia de la técnica de inmunofluorescencia indirecta (IFI) con la reacción de polimerasa en cadena (RPC) para identificar virus respiratorios en niños hospitalizados por IRA. Métodos: Se incluyeron 47 aspirados nasofaríngeos de niños ≤ 2 años con IRA. La IFI incluyó virus respiratorio sincicial (VRS), adenovirus, influenza A y B y parainfluenza. La RPC incluyó, además, la detección de metapneumovirus, enterovirus/rinovirus, bocavirus y coronavirus. Se estimó sensibilidad, especificidad, valor predictor positivo y negativo (VPP/VPN) y correlación kappa para VRS mediante IFI en comparación a la RPC. Resultados: La IFI detectó únicamente VRS (29; 61,7%). La RPC detectó diversos virus, entre ellos VRS en 26 casos (55,3%), seguido por bocavirus (29,8%), enterovirus/ rinovirus (21,3%), adenovirus (14,9%) y parainfluenza (4,3%) entre otros, con 35,5% de co-infección. La IFI presentó sensibilidad: 85,7%, especificidad: 73,6%, VPP: 82,7%, VPN: 77,7% y kappa: 0,5990 (IC 95%; 0,36360,8346) para VRS. Conclusión: La IFI presenta buena sensibilidad, pero moderada especificidad para VRS. Sin embargo, falla en la detección de otros virus respiratorios. La introducción de RPC permitiría mejorar el diagnóstico etiológico de las IRA de origen viral.


Background: Early viral detection in acute respiratory infections (ARI) is essential to establish appropriate therapy and prevent nosocomial transmission. Objective: To compare the efficacy of indirect immunofluorescence technique (IIF) with the polymerase chain reaction (PCR) to identify respiratory viruses in children hospitalized for ARI. Methods: 47 nasopharyngeal aspirates of children ≤ 2 years with ARI were included. IFI included respiratory syncytial virus (RSV), adenovirus, influenza A and B and parainfluenza. PCR also included the detection of metapneumovirus, enterovirus/rhinovirus, bocavirus and coronavirus. Sensitivity, specificity, positive and negative predictive value (VPP/NPV) and kappa correlation for RSV were estimated by IIF compared to PCR. Results: The IIF detected only RSV (29; 61.7%). PCR detected several viruses, including RSV in 26 cases (55.3%), followed by bocavirus (29.8%), rhinovirus/enterovirus (21.3%), adenovirus (14.9%) and parainfluenza (4,3%) among others, with 35.5% of coinfection. The IIF presented sensitivity: 85.7%, specificity: 73.6%, PPV: 82.7%, NPV: 77.7% and kappa: 0.5990 (95% CI, 0.3636-0.8346) for RSV. Conclusion: The IIF presents good sensitivity, but moderate specificity for RSV. However, IIF fails to detect other respiratory viruses. The introduction of PCR would improve the etiological diagnosis of ARI of viral origin.


Subject(s)
Humans , Male , Female , Infant , Child, Preschool , Child , Adolescent , Viruses/isolation & purification , Nasopharynx/virology , Polymerase Chain Reaction/methods , Fluorescent Antibody Technique, Indirect/methods , Respiratory Tract Infections/virology , RNA Viruses/isolation & purification , Chile , Cross-Sectional Studies , Prospective Studies , Reproducibility of Results , Sensitivity and Specificity , DNA Viruses/isolation & purification
7.
Rev. Soc. Bras. Med. Trop ; 52: e20180323, 2019. graf
Article in English | LILACS | ID: biblio-1003132

ABSTRACT

Abstract We report the case of a 32-year-old man from Rio de Janeiro, who was infected in the Amazon region of Brazil by Leishmania (Viannia) naiffi. Generally, patients with L. naiffi cutaneous leishmaniasis exhibit a good therapeutic response to either pentavalent antimonials or pentamidine. However, after pentamidine treatment, this patient's infection evolved to therapeutic failure. To understand this clinical outcome, we investigated the presence of the Leishmania RNA virus (LRV) in parasites isolated from the cutaneous lesion; herein, we discuss the possible association between a poor response to pentamidine therapy and the presence of the LRV.


Subject(s)
Humans , Male , Adult , Pentamidine/therapeutic use , RNA Viruses/genetics , Trypanocidal Agents/therapeutic use , Leishmaniasis, Cutaneous/drug therapy , Leishmania/virology , Pentamidine/adverse effects , Trypanocidal Agents/adverse effects , Polymerase Chain Reaction , Treatment Failure
8.
Article in English | WPRIM | ID: wpr-764240

ABSTRACT

Zika virus (ZIKV) is one of the pathogens which is transmitted world widely, but there are no effective drugs and vaccines. Whole genome sequencing (WGS) of viruses could be applied to viral pathogen characterization, diagnosis, molecular surveillance, and even finding novel pathogens. We established an improved method using direct RNA sequencing with Nanopore technology to obtain WGS of ZIKV, after adding poly (A) tails to viral RNA. This established method does not require specific primers, complimentary DNA (cDNA) synthesis, and polymerase chain reaction (PCR)-based enrichment, resulting in the reduction of biases as well as of the ability to find novel RNA viruses. Nanopore technology also allows to read long sequences. It makes WGS easier and faster with long-read assembly. In this study, we obtained WGS of two strains of ZIKV following the established protocol. The sequenced reads resulted in 99% and 100% genome coverage with 63.5X and 21,136X, for the ZIKV PRVABC59 and MR 766 strains, respectively. The sequence identities of the ZIKV PRVABC59 and MR 766 strains for each reference genomes were 98.76% and 99.72%, respectively. We also found that the maximum length of reads was 10,311 bp which is almost the whole genome size of ZIKV. These long-reads could make overall structure of whole genome easily, and WGS faster and easier. The protocol in this study could provide rapid and efficient WGS that could be applied to study the biology of RNA viruses including identification, characterization, and global surveillance.


Subject(s)
Bias , Biology , Diagnosis , DNA , Genome , Genome Size , Methods , Nanopores , Polymerase Chain Reaction , RNA Viruses , RNA , RNA, Viral , Sequence Analysis, RNA , Tail , Vaccines , Zika Virus
9.
Article in English | WPRIM | ID: wpr-717995

ABSTRACT

Human rhinoviruses (HRV) are one of the major causes of common cold in humans and are also associated with acute asthma and bronchial illness. Heat-shock protein 90 (Hsp90), a molecular chaperone, is an important host factor for the replication of single-strand RNA viruses. In the current study, we examined the effect of the Hsp90 inhibitor pochonin D, in vitro and in vivo, using a murine model of human rhinovirus type 1B (HRV1B) infection. Our data suggested that Hsp90 inhibition significantly reduced the inflammatory cytokine production and lung damage caused by HRV1B infection. The viral titer was significantly lowered in HRV1B-infected lungs and in Hela cells upon treatment with pochonin D. Infiltration of innate immune cells including granulocytes and monocytes was also reduced in the bronchoalveolar lavage (BAL) by pochonin D treatment after HRV1B infection. Histological analysis of the lung and respiratory tract showed that pochonin D protected the mice from HRV1B infection. Collectively, our results suggest that the Hsp90 inhibitor, pochonin D, could be an attractive antiviral therapeutic for treating HRV infection.


Subject(s)
Animals , Asthma , Bronchoalveolar Lavage , Common Cold , Granulocytes , Heat-Shock Proteins , HeLa Cells , Hot Temperature , Humans , In Vitro Techniques , Lung , Mice , Molecular Chaperones , Monocytes , Respiratory System , Rhinovirus , RNA Viruses
10.
Article in English | WPRIM | ID: wpr-714742

ABSTRACT

Defensins are antimicrobial peptides that participate in the innate immunity of hosts. Humans constitutively and/or inducibly express α- and β-defensins, which are known for their antiviral and antibacterial activities. This review describes the application of human defensins. We discuss the extant experimental results, limited though they are, to consider the potential applicability of human defensins as antiviral agents. Given their antiviral effects, we propose that basic research be conducted on human defensins that focuses on RNA viruses, such as human immunodeficiency virus (HIV), influenza A virus (IAV), respiratory syncytial virus (RSV), and dengue virus (DENV), which are considered serious human pathogens but have posed huge challenges for vaccine development for different reasons. Concerning the prophylactic and therapeutic applications of defensins, we then discuss the applicability of human defensins as antivirals that has been demonstrated in reports using animal models. Finally, we discuss the potential adjuvant-like activity of human defensins and propose an exploration of the ‘defensin vaccine’ concept to prime the body with a controlled supply of human defensins. In sum, we suggest a conceptual framework to achieve the practical application of human defensins to combat viral infections.


Subject(s)
Antiviral Agents , Defensins , Dengue Virus , HIV , Humans , Immunity, Innate , Influenza A virus , Models, Animal , Peptides , Respiratory Syncytial Viruses , RNA Viruses
11.
Article in English | WPRIM | ID: wpr-741491

ABSTRACT

Canine coronavirus is a single-stranded RNA virus that causes enteritis in dogs of any age. Coronaviral enteritis is seldom definitively diagnosed, since it is usually much less severe than many other types of enteritis and is self-limiting. Conventional diagnostics for the canine coronaviral enteritis such as polymerase chain reaction (PCR), virus isolation, and electron microscopic examination are inappropriate for small animal clinics due to the complicated experimental processes involved. Therefore, a commercially available lateral flow test kit based on chromatographic immunoassay techniques was tested to evaluate its performance as a first-line diagnostic test kit that could be used in clinics. The coronavirus antigen test kit detected canine coronavirus-infected dogs with 93.1% sensitivity and 97.5% specificity. The detection limit of the test kit was between 1.97 × 10⁴/mL and 9.85 × 10³/mL for samples with a 2-fold serial dilution from 1.25 × 10⁶ TCID₅₀ (TCID₅₀, 50% tissue culture infectious dose). Additionally, the test kit had no cross-reactivity with canine parvovirus, distemper virus, or Escherichia coli. Overall, the commercially available test kit showed good diagnostic performance in a clinical setting, with results similar to those from PCR, confirming their potential for convenient and accurate use in small animal clinics.


Subject(s)
Animals , Coronavirus , Coronavirus, Canine , Diagnostic Tests, Routine , Distemper , Dogs , Enteritis , Escherichia coli , Immunoassay , Limit of Detection , Parvovirus, Canine , Polymerase Chain Reaction , Reagent Kits, Diagnostic , RNA Viruses , Sensitivity and Specificity
12.
Article in English | WPRIM | ID: wpr-758868

ABSTRACT

In many countries, vaccines are used for the prevention of foot-and-mouth disease (FMD). However, because there is no protection against FMD immediately after vaccination, research and development on antiviral agents is being conducted to induce protection until immunological competence is produced. This study tested whether well-known chemicals used as RNA virus treatment agents had inhibitory effects on FMD viruses (FMDVs) and demonstrated that ribavirin showed antiviral effects against FMDV in vitro/in vivo. In addition, it was observed that combining the administration of the antiviral agents orally and complementary therapy with vaccines synergistically enhanced antiviral activity and preserved the survival rate and body weight in the experimental animals. Antiviral agents mixed with an adjuvant were inoculated intramuscularly along with the vaccines, thereby inhibiting virus replication after injection and verifying that it was possible to induce early protection against viral infection prior to immunity being achieved through the vaccine. Finally, pigs treated with antiviral agents and vaccines showed no clinical signs and had low virus excretion. Based on these results, it is expected that this combined approach could be a therapeutic and preventive treatment for early protection against FMD.


Subject(s)
Animals , Antiviral Agents , Body Weight , Foot-and-Mouth Disease , Immunocompetence , Ribavirin , RNA Viruses , Survival Rate , Swine , Vaccination , Vaccines , Virus Replication
13.
Mem. Inst. Oswaldo Cruz ; 113(4): e170487, 2018. graf
Article in English | LILACS | ID: biblio-894910

ABSTRACT

Viruses of trypanosomatids are now being extensively studied because of their diversity and the roles they play in flagellates' biology. Among the most prominent examples are leishmaniaviruses implicated in pathogenesis of Leishmania parasites. Here, we present a historical overview of this field, starting with early reports of virus-like particles on electron microphotographs, and culminating in detailed molecular descriptions of viruses obtained using modern next generation sequencing-based techniques. Because of their diversity, different life cycle strategies and host specificity, we believe that trypanosomatids are a fertile ground for further explorations to better understand viral evolution, routes of transitions, and molecular mechanisms of adaptation to different hosts.


Subject(s)
RNA Viruses , Trypanosomatina/virology , Microscopy, Electron, Scanning Transmission , Leishmaniavirus/physiology , Host Specificity
14.
Mem. Inst. Oswaldo Cruz ; 112(5): 339-347, May 2017. tab, graf
Article in English | LILACS | ID: biblio-841791

ABSTRACT

BACKGROUND Real-time reverse transcription polymerase chain reaction (RT-PCR) is routinely used to detect viral infections. In Brazil, it is mandatory the use of nucleic acid tests to detect hepatitis C virus (HCV), hepatitis B virus and human immunodeficiency virus in blood banks because of the immunological window. The use of an internal control (IC) is necessary to differentiate the true negative results from those consequent from a failure in some step of the nucleic acid test. OBJECTIVES The aim of this study was the construction of virus-modified particles, based on MS2 bacteriophage, to be used as IC for the diagnosis of RNA viruses. METHODS The MS2 genome was cloned into the pET47b(+) plasmid, generating pET47b(+)-MS2. MS2-like particles were produced through the synthesis of MS2 RNA genome by T7 RNA polymerase. These particles were used as non-competitive IC in assays for RNA virus diagnostics. In addition, a competitive control for HCV diagnosis was developed by cloning a mutated HCV sequence into the MS2 replicase gene of pET47b(+)-MS2, which produces a non-propagating MS2 particle. The utility of MS2-like particles as IC was evaluated in a one-step format multiplex real-time RT-PCR for HCV detection. FINDINGS We demonstrated that both competitive and non-competitive IC could be successfully used to monitor the HCV amplification performance, including the extraction, reverse transcription, amplification and detection steps, without compromising the detection of samples with low target concentrations. In conclusion, MS2-like particles generated by this strategy proved to be useful IC for RNA virus diagnosis, with advantage that they are produced by a low cost protocol. An attractive feature of this system is that it allows the construction of a multicontrol by the insertion of sequences from more than one pathogen, increasing its applicability for diagnosing different RNA viruses.


Subject(s)
RNA Viruses/genetics , Hepatitis C/diagnosis , Hepacivirus/genetics , Escherichia coli/genetics , Real-Time Polymerase Chain Reaction/methods , Levivirus/genetics , Models, Biological
15.
Article in English | WPRIM | ID: wpr-165996

ABSTRACT

Recent advances in reverse genetics techniques make it possible to manipulate the genome of RNA viruses such as Newcastle disease virus (NDV). Several NDV vaccine strains have been used as vaccine vectors in poultry, mammals, and humans to express antigens of different pathogens. The safety, immunogenicity, and protective efficacy of these NDV-vectored vaccines have been evaluated in pre-clinical and clinical studies. The vaccines are safe in mammals, humans, and poultry. Bivalent NDV-vectored vaccines against pathogens of economic importance to the poultry industry have been developed. These bivalent vaccines confer solid protective immunity against NDV and other foreign antigens. In most cases, NDV-vectored vaccines induce strong local and systemic immune responses against the target foreign antigen. This review summarizes the development of NDV-vectored vaccines and their potential use as a base for designing other effective vaccines for veterinary and human use.


Subject(s)
Animals , Genome , Humans , Mammals , Newcastle disease virus , Newcastle Disease , Poultry , Reverse Genetics , RNA Viruses , Vaccines
16.
Immune Network ; : 261-270, 2016.
Article in English | WPRIM | ID: wpr-139327

ABSTRACT

The human immune system has evolved to fight against foreign pathogens. It plays a central role in the body's defense mechanism. However, the immune memory geared to fight off a previously recognized pathogen, tends to remember an original form of the pathogen when a variant form subsequently invades. This has been termed 'original antigenic sin'. This adverse immunological effect can alter vaccine effectiveness and sometimes cause enhanced pathogenicity or additional inflammatory responses, according to the type of pathogen and the circumstances of infection. Here we aim to give a simplified conceptual understanding of virus infection and original antigenic sin by comparing and contrasting the two examples of recurring infections such as influenza and dengue viruses in humans.


Subject(s)
Dengue , Dengue Virus , Humans , Immune System , Influenza, Human , Memory , RNA Viruses , RNA , Virulence
17.
Immune Network ; : 261-270, 2016.
Article in English | WPRIM | ID: wpr-139322

ABSTRACT

The human immune system has evolved to fight against foreign pathogens. It plays a central role in the body's defense mechanism. However, the immune memory geared to fight off a previously recognized pathogen, tends to remember an original form of the pathogen when a variant form subsequently invades. This has been termed 'original antigenic sin'. This adverse immunological effect can alter vaccine effectiveness and sometimes cause enhanced pathogenicity or additional inflammatory responses, according to the type of pathogen and the circumstances of infection. Here we aim to give a simplified conceptual understanding of virus infection and original antigenic sin by comparing and contrasting the two examples of recurring infections such as influenza and dengue viruses in humans.


Subject(s)
Dengue , Dengue Virus , Humans , Immune System , Influenza, Human , Memory , RNA Viruses , RNA , Virulence
18.
Article in English | WPRIM | ID: wpr-60758

ABSTRACT

Hepatitis C virus (HCV) infection is a major medical challenge affecting around 200 million people worldwide. The main site of HCV replication is the hepatocytes of the liver. HCV is a positive enveloped RNA virus from the flaviviridae family. Six major HCV genotypes are implicated in the human infection. In developed countries the children are infected mainly through vertical transmission during deliveries, while in developing countries it is still due to horizontal transmission from adults. Minimal nonspecific and brief symptoms are initially found in approximately 15% of children. Acute and chronic HCV infection is diagnosed through the recognition of HCV RNA. The main objective for treatment of chronic HCV is to convert detected HCV viremia to below the detection limit. Children with chronic HCV infection are usually asymptomatic and rarely develop severe liver damage. Therefore, the benefits from current therapies, pegylated-Interferon plus ribavirin, must be weighed against their adverse effects. This combined treatment offers a 50-90% chance of clearing HCV infection according to several studies and on different HCV genotype. Recent direct acting antiviral (DAA) drugs which are well established for adults have not yet been approved for children and young adults below 18 years. The most important field for the prevention of HCV infection in children would be the prevention of perinatal and parenteral transmission. There are areas of focus for new lines of research in pediatric HCV-related disease that can be addressed in the near future.


Subject(s)
Adult , Child , Developed Countries , Developing Countries , Epidemiology , Flaviviridae , Genotype , Hepacivirus , Hepatitis C , Hepatitis , Hepatocytes , Humans , Limit of Detection , Liver , Ribavirin , RNA , RNA Viruses , Viremia , Young Adult
19.
Braz. j. otorhinolaryngol. (Impr.) ; 81(5): 533-540, Sept.-Oct. 2015. tab, graf
Article in English | LILACS | ID: lil-766282

ABSTRACT

ABSTRACT INTRODUCTION: Mucosal leishmaniosis (ML) is a severe clinical form of leishmaniosis. Complex factors related to the parasite and the host are attributed to the development of mucosal lesions. Leishmania RNA virus 1 (LRV1) can disrupt immune response, and may be the main determinant of severity of the disease; it should be investigated. OBJECTIVE: To study the existence of clinical differences between patients with ML with endosymbiosis by LRV1 and. those without it. METHODS: A cross-sectional cohort study with clinical evaluation, polymerase chain reaction (PCR) detection of Leishmania, species classification, and search of LRV1 was performed. Only patients with confirmed diagnosis of ML by positive PCR and with nasal mucosa injuries were included in this analysis. RESULTS: Out of 37 patients, 30 (81.1%) were diagnosed with Leishmania braziliensis, five (13.5%) with Leishmania guyanensis, and two (5.4%) with mixed infection of L. braziliensis and L. guyanensis. LVR1 virus was present in 26 (70.3%) of the cases. CONCLUSION: Correlation between clinical phenotype and presence of LRV1 was not observed, although the frequency of the virus is two-fold higher in mucosal lesions than that found in the literature on skin lesions in the same geographical area.


RESUMO Introdução: A leishmaniose de mucosa (LM) é uma forma clínica grave da leishmaniose. Fatores complexos ligados ao parasita e ao hospedeiro são atribuídos ao desenvolvimento das lesões de mucosa. Leishmania RNA Vírus 1 (LRV1) pode subverter a resposta imune, podendo ser o principal determinante da gravidade da doença e deve ser pesquisado. Objetivo: Estudar a existência de diferenças clínicas entre pacientes portadores de LM com endosimbiose por LRV1 e as que não possuem. Métodos: Foi realizado um estudo de coorte histórica com corte transversal com avaliação clínica, detecção da Leishmania por técnica de PCR, classificação da espécie e pesquisa de LRV1. Foram incluídos na análise da pesquisa somente os pacientes com diagnóstico confirmado de LM com PCR positivo, com lesão de mucosa nasal. Resultados: Dos 37 pacientes, 30 (81,1%) foram diagnosticados com L. braziliensis, 5 (13,5%) com L. guyanensis e 2 (5,4%) com infecção mista de L. braziliensis e L. guyanensis. O vírus LVR1 estava presente em 26 casos (70,3%). Conclusão: A correlação entre o fenótipo clínico e a presença do LRV1 não foi constatada, porém a frequência do vírus é duas vezes maior em lesão de mucosa do que encontrado em trabalho, da mesma região, sobre lesão cutânea.


Subject(s)
Adolescent , Adult , Aged , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Young Adult , Leishmania/virology , Leishmaniasis, Mucocutaneous/virology , Leishmaniavirus/genetics , Nasal Mucosa/parasitology , RNA Viruses/genetics , Cohort Studies , Cross-Sectional Studies , Leishmania/classification , Leishmaniasis, Mucocutaneous/genetics , Phenotype , Polymerase Chain Reaction , Severity of Illness Index
20.
Belo Horizonte; s.n; 2015. XV, 79 p.
Thesis in Portuguese | LILACS, ColecionaSUS | ID: biblio-940888

ABSTRACT

A família Bunyaviridae consiste em uma das maiores e mais diversificadas famílias de vírus de RNA, contendo cerca de 350 vírus sorologicamente distintos. O Apeu virus (APEUV) é um vírus da família Bunyaviridae que se destaca por seu grande potencial emergente. Isolado pela primeira no Brasil, este vírus pode causar uma doença que apresenta sintomas semelhantes aos da gripe, como febre alta, dor de cabeça e mialgia, associadas geralmente a náuseas, vômitos, fraqueza e fotofobia. Entretanto, apesar de seu potencial patogênico, pouco se sabe sobre a sua interação com o sistema imunológico humano. Com o objetivo de estudar alguns aspectos da resposta imune, principalmente a reposta inata desencadeada pela infecção do APEUV, a expressão de 19 genes (TLR3, TLR7, TLR8, TLR9, MyD88,IRF3, IRF5, IRF7, IRF9, IRAK4, TRAF3, TRAF6, TICAM1, JUN, ROBO-3(RIG-1),IFIH1(MDA-5), IFNα, IFNβ, IFNy) foi analisada. Para tal, foram feitos ensaios de qPCR baseados na metodologia TaqMan®, utilizando cDNA obtido a partir de RNA total extraído de células mononucleares do sangue periférico (PBMC) e de células A549 (linhagem derivada de carcinoma pulmonar humano), infectadas ou não com APEUV por períodos de 4 ou 8 horas.


Como controles, foram utilizadas células infectadas com o vírus da estomatite vesicular (VSV) como controle positivo de uma infecção por vírus de RNA fita simples, e células tratadas com o mock das amostras de vírus como controle negativo. Os dados obtidos foram analisados em software específico. Nossos resultados indicam que PBMC infectadas com APEUV por 4horas (m.o.i.=1 e m.o.i.=3) induzem um aumento na expressão de TLR9 e IFNβ. Quando quantificada a expressão de genes em células A549 infectadas com APEUV(m.o.i.=1 por 4 horas) comparadas com o mock, verificou-se um aumento da expressão dos genes TLR9, IRF3 e IRF7 e no período de 8 horas, também comparando com o mock, verificou-se aumento de forma significativa na expressão de TLR 9, além de um aumento na expressão de TLR3, TLR7, TRAF3 , IRF7 e IFNβ.Verificamos ainda que, após escolher um gene housekeeping através de método estatístico, células A549 infectadas com APEUV em uma m.o.i.=1, tende a aumentara expressão dos genes IFNβ e TICAM-I, fundamentais na indução de um estado celular antiviral. Estudos posteriores são necessários para a determinação dos mecanismos envolvidos na resposta imune inata humana contra o Apeu virus.


Subject(s)
Male , Female , Humans , Bunyaviridae/isolation & purification , RNA Virus Infections/immunology , RNA Viruses/pathogenicity
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