ABSTRACT
Abstract Colletotrichum is one of the most economically important fungal genera, which affects a wide range of hosts, specifically tropical and subtropical crops. Thus far, there have been several records of mycovirus infection in Colletotrichum spp., primarily by viruses of the Partitiviridae family. There have also been records of infections by mycoviruses of the Chrysoviridae family. Mycoviruses are (+)ssRNA and dsRNA genome viruses, which may or may not be enveloped. To date, no mycovirus with a DNA genome has been isolated from Colletotrichum spp. Typically, mycoviruses cause latent infections, although hypo- and hypervirulence have also been reported in Colletotrichum spp. In addition to its effects on pathogenic behavior, mycovirus infection can lead to important physiological changes, such as altered morphological characteristics, reduced vegetative growth, and suppressed conidia production. Therefore, research on mycoviruses infecting phytopathogenic fungi can help develop alternative methods to chemical control, which can cause irreversible damage to humans and the environment. From an agricultural perspective, mycoviruses can contribute to sustainable agriculture as biological control agents via changes in fungal physiology, ultimately resulting in the total loss of or reduction in the virulence of these pathogens.
Resumo Colletotrichum é um dos gêneros fúngicos mais importantes economicamente, afetando uma ampla gama de hospedeiros, especialmente em cultivos tropicais e subtropicais. Atualmente já existem diversos registros de infecção por micovírus em Colletotrichum spp., sendo a maioria dos já identificados classificados na família Partitiviridae. Ocorrem registros também de micovírus pertencentes à família Chrysoviridae. Compreendem vírus de genoma de (+)ssRNA e dsRNA que podem ser ou não envelopados. Ainda não foram identificados micovírus com genoma de DNA isolados de Colletotrichum. A infecção por micovírus pode ocorrer de forma latente, mas já foi observado em Colletotrichum spp. o fenômeno de hipo e hipervirulência. Além de influenciar no comportamento patogênico, a infecção pode causar mudanças fisiológicas importantes como alterações das características morfológicas, redução do crescimento vegetativo e redução na produção de conídios. O estudo com micovírus em fungos fitopatogênicos traz uma alternativa ao controle químico que é um método capaz de causar danos irreversíveis ao homem e o meio ambiente. Sob a perspectiva agrícola, os micovírus podem contribuir para agricultura sustentável como agentes de controle biológico. Isso porque obsevam-se mudanças importantes na fisiologia fúngica resultando na perda total ou redução da virulência desses patógenos.
Subject(s)
Humans , RNA Viruses , Colletotrichum , Fungal Viruses/genetics , Phylogeny , Spores, Fungal , VirulenceABSTRACT
La enfermedad por coronavirus (COVID-19) producida por el SARS-CoV-2 ha sido un reto para los servicios de salud en todo el mundo. La pandemia se ha extendido ampliamente con más de 80 millones de casos confirmados y más de un millón de muertes a nivel mundial, por lo que ha estado bajo constante investigación para entender todos los aspectos de la enfermedad. Recientemente se han reportado varios casos de pacientes con síndrome de Guillain-Barré asociado a COVID-19 como manifestación principal, convirtiéndola en la primera enfermedad neurológica autoinmune desencadenada por SARS-CoV-2; sin embargo, es necesario obtener más información para entender completamente los mecanismos inmunopatogénicos implicados en esta asociación.
The coronavirus disease (COVID-19) caused by SARS-CoV-2 has been a challenge for health services around the world. The pandemic has spread widely, with more than 80 million confirmed cases and more than one million deaths globally. There have been many studies to understand all aspects of the disease. Recently, several cases have been reported of patients with Guillain-Barré syndrome associated with COVID-19 as the main manifestation. As it may be one of the first autoimmune neurological diseases triggered by SARS-CoV-2, it is necessary to obtain more information to fully understand the immunopathogenic mechanisms involved in this association.
Subject(s)
Humans , Male , Female , Aged , RNA Viruses , Viruses , Coronavirus , Autoimmune Diseases of the Nervous System , Guillain-Barre Syndrome , Nervous System DiseasesABSTRACT
RNA viruses cause a multitude of human diseases, including several pandemic events in the past century. Upon viral invasion, the innate immune system responds rapidly and plays a key role in activating the adaptive immune system. In the innate immune system, the interactions between pathogen-associated molecular patterns and host pattern recognition receptors activate multiple signaling pathways in immune cells and induce the production of pro-inflammatory cytokines and interferons to elicit antiviral responses. Macrophages, dendritic cells, and natural killer cells are the principal innate immune components that exert antiviral activities. In this review, the current understanding of innate immunity contributing to the restriction of RNA viral infections was briefly summarized. Besides the main role of immune cells in combating viral infection, the intercellular transfer of pathogen and host-derived materials and their epigenetic and metabolic interactions associated with innate immunity was discussed. This knowledge provides an enhanced understanding of the innate immune response to RNA viral infections in general and aids in the preparation for the existing and next emerging viral infections.
Subject(s)
Humans , Immunity, Innate , Interferons , RNA , RNA Viruses , Virus DiseasesABSTRACT
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 , Humans , Mice , 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 , Influenza A virus , Leflunomide , Pharmacology , 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 ReplicationABSTRACT
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 , Humans , Mice , 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 , Influenza A virus , Leflunomide , Pharmacology , 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 ReplicationABSTRACT
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 , Humans , Mice , 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 , Influenza A virus , Leflunomide , Pharmacology , 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 ReplicationABSTRACT
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 dataABSTRACT
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 & purificationABSTRACT
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 FailureABSTRACT
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 VirusABSTRACT
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 , Humans , Mice , Asthma , Bronchoalveolar Lavage , Common Cold , Granulocytes , Heat-Shock Proteins , HeLa Cells , Hot Temperature , In Vitro Techniques , Lung , Molecular Chaperones , Monocytes , Respiratory System , Rhinovirus , RNA VirusesABSTRACT
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 SpecificityABSTRACT
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)
Humans , Antiviral Agents , Defensins , Dengue Virus , HIV , Immunity, Innate , Influenza A virus , Models, Animal , Peptides , Respiratory Syncytial Viruses , RNA VirusesABSTRACT
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 , Dogs , Coronavirus , Coronavirus, Canine , Diagnostic Tests, Routine , Distemper , Enteritis , Escherichia coli , Immunoassay , Limit of Detection , Parvovirus, Canine , Polymerase Chain Reaction , Reagent Kits, Diagnostic , RNA Viruses , Sensitivity and SpecificityABSTRACT
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 ReplicationABSTRACT
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, BiologicalABSTRACT
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 , Humans , Genome , Mammals , Newcastle disease virus , Newcastle Disease , Poultry , Reverse Genetics , RNA Viruses , VaccinesABSTRACT
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)
Humans , Dengue , Dengue Virus , Immune System , Influenza, Human , Memory , RNA Viruses , RNA , VirulenceABSTRACT
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.