RESUMEN
The COVID-19 pandemic caused by the SARS-CoV-2 virus has highlighted the need for serological assays that can accurately evaluate the neutralizing efficiency of antibodies produced during infection or induced by vaccines. However, conventional assays often require the manipulation of live viruses on a level-three biosafety (BSL3) facility, which presents practical and safety challenges. Here, we present a novel, alternative assay that measures neutralizing antibodies (NAbs) against SARS-CoV-2 in plasma using flow cytometry. This assay is based on antibody binding to the S protein and has demonstrated precision in both intra- and inter-assay measurements at a dilution of 1:50. The cut-off was determined using Receiver Operating Characteristic (ROC) analysis and the value of 36.01% has shown high sensitivity and specificity in distinguishing between pre-pandemic sera, COVID-19 patients, and vaccinated individuals. The efficiency significantly correlates with the gold standard test, PRNT. Our new assay offers a safe and efficient alternative to conventional assays for evaluating NAbs against SARS-CoV-2.
Asunto(s)
Anticuerpos Neutralizantes , Anticuerpos Antivirales , COVID-19 , Citometría de Flujo , SARS-CoV-2 , Humanos , Citometría de Flujo/métodos , SARS-CoV-2/inmunología , Anticuerpos Neutralizantes/inmunología , Anticuerpos Neutralizantes/sangre , COVID-19/inmunología , COVID-19/diagnóstico , COVID-19/virología , Anticuerpos Antivirales/inmunología , Anticuerpos Antivirales/sangre , Glicoproteína de la Espiga del Coronavirus/inmunología , Pruebas de Neutralización/métodos , Prueba Serológica para COVID-19/métodos , Sensibilidad y Especificidad , Masculino , FemeninoRESUMEN
Yellow fever (YF) virus is a mosquito-borne virus belonging to the Flaviviridae family that circulates in tropical and subtropical areas of Africa and South America. Despite the availability of an effective vaccine, YF remains a threat to travelers, residents of endemic areas, and unvaccinated populations. YF vaccination and natural infection both induce the production of neutralizing antibodies. Serological diagnostic methods detecting YF virus-specific antibodies demonstrate high levels of cross-reactivities with other flaviviruses. To date, the plaque reduction neutralization test (PRNT) is the most specific serological test for the differentiation of flavivirus infections and is considered the reference method for detecting YF neutralizing antibodies and assessing the protective immune response following vaccination. In this study, we developed and validated a YF PRNT. We optimized different parameters including cell concentration and virus-serum neutralization time period and then assessed the intra- and inter-assay precisions, dilutability, specificity, and lower limit of quantification (LLOQ) using international standard YF serum, sera from vaccinees and human specimens collected through YF surveillance. The YF PRNT has shown good robustness and 100% of intra-assay precision, 95.6% of inter-assay precision, 100% of specificity, 100% of LLOQ, and 95.3% of dilutability. The test is, therefore, suitable for use in the YF diagnostic as well as evaluation of the YF vaccine neutralizing antibody response and risk assessment studies.
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Vacunas , Vacuna contra la Fiebre Amarilla , Fiebre Amarilla , Humanos , Fiebre Amarilla/diagnóstico , Fiebre Amarilla/prevención & control , Pruebas de Neutralización , Virus de la Fiebre Amarilla , Anticuerpos Neutralizantes , Anticuerpos AntiviralesRESUMEN
BACKGROUND: As countries move towards or achieve measles elimination status, serosurveillance is an important public health tool. However, a major challenge of serosurveillance is finding a feasible, accurate, cost-effective, and high throughput assay to measure measles antibodyâ¯concentrationsâ¯and estimate susceptibility in a population. We conducted a systematic review to assess, characterize, and - to the extent possible - quantify the performance of measles IgG enzyme-linked assays (EIAs) compared to the gold standard, plaque reduction neutralization tests (PRNT). METHODS: We followed the PRISMA statement for a systematic literature search and methods for conducting and reporting systematic reviews and meta-analyses recommended by the Cochrane Screening and Diagnostic Tests Methods Group. We identified studies through PubMed and Embase electronic databases and included serologic studies detecting measles virus IgG antibodies among participants of any age from the same source population that reported an index (any EIA or multiple bead-based assays, MBA) and reference test (PRNT) using sera, whole blood, or plasma. Measures of diagnostic accuracy with 95% confidence intervals (CI) were abstracted for each study result, where reported. RESULTS: We identified 550 unique publications and identified 36 eligible studies for analysis. We classified studies as high, medium, or low quality; results from high quality studies are reported. Because most high quality studies used the Siemens Enzygnost EIA kit, we generate individual and pooled diagnostic accuracy estimates for this assay separately. Median sensitivity of the Enzygnost EIA was 92.1% [IQR = 82.3, 95.7]; median specificity was 96.9 [93.0, 100.0]. Pooled sensitivity and specificity from studies using the Enzygnost kit were 91.6 (95%CI: 80.7,96.6) and 96.0 (95%CI: 90.9,98.3), respectively. The sensitivity of all other EIA kits across high quality studies ranged from 0% to 98.9% with median (IQR) = 90.6 [86.6, 95.2]; specificity ranged from 58.8% to 100.0% with median (IQR) = 100.0 [88.7, 100.0]. CONCLUSIONS: Evidence on the diagnostic accuracy of currently available measles IgG EIAs is variable, insufficient, and may not be fit for purpose for serosurveillance goals. Additional studies evaluating the diagnostic accuracy of measles EIAs, including MBAs, should be conducted among diverse populations and settings (e.g., vaccination status, elimination/endemic status, age groups).
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Sarampión , Humanos , Pruebas de Neutralización/métodos , Técnicas para Inmunoenzimas , Virus del Sarampión , Sensibilidad y Especificidad , Anticuerpos Antivirales , Inmunoglobulina GRESUMEN
Dietary fiber is considered an essential constituent of a healthy child's diet. Diets of healthy children with adequate dietary fiber intake are characterized by a higher diet quality, a higher nutrient density, and a higher intake of vitamins and minerals in comparison to the diets of children with poor dietary fiber intake. Nevertheless, a substantial proportion of children do not meet the recommended dietary fiber intake. This is especially true in those children with kidney diseases, as traditional dietary recommendations in kidney diseases have predominantly focused on the quantities of energy and protein, and often restricting potassium and phosphate, while overlooking the quality and diversity of the diet. Emerging evidence suggests that dietary fiber and, by extension, a plant-based diet with its typically higher dietary fiber content are just as important for children with kidney diseases as for healthy children. Dietary fiber confers several health benefits such as prevention of constipation and fewer gastrointestinal symptoms, reduced inflammatory state, and decreased production of gut-derived uremic toxins. Recent studies have challenged the notion that a high dietary fiber intake confers an increased risk of hyperkalemia or nutritional deficits in children with kidney diseases. There is an urgent need of new studies and revised guidelines that address the dietary fiber intake in children with kidney diseases.
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Dieta , Fibras de la Dieta , Niño , Humanos , Estreñimiento/etiología , Vitaminas , Tracto GastrointestinalRESUMEN
Our previous study has firstly pointed that three nucleotide variants (g.-11C > T, g.117A > G, and g.149C > T) of the goat PRNT gene can significantly influence litter size. Given litter size is positively correlated with growth performance, we consider whether the PRNT gene also acts on the growth performance in goats. In this work, a correlation analysis among different litter size types and growth traits of Shaanbei white cashmere (SBWC) goats was performed, and results showed that a positive correlation did exist in our detected population (P < 0.01). Then, the association among different genotypes of three variations and goat growth performance was measured. Our results pointed to g.117A > G being significantly associated with the cannon circumference (P = 4.60E-05) while no significant effect was found between another two SNPs and growth traits after the Bonferroni's correction (P*n < 0.05). Together, this is the first report about the influence of the PRNT gene on the growth of goat and g.117A > G can be regarded as a possible DNA marker applying for MAS breeding.
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Cabras , Nucleótidos , Embarazo , Femenino , Animales , Cabras/genética , Tamaño de la Camada/genética , Genotipo , FenotipoRESUMEN
BACKGROUND: Patients recovering from COVID-19 may need vaccination against SARS-CoV-2 because acquired immunity from primary infection may wane, given the emergence of new SARS-CoV-2 variants. Understanding the trends of anti-spike IgG and neutralizing antibody titers in patients recovering from COVID-19 may inform the decision made on the appropriate interval between recovery and vaccination. METHODS: Participants aged 20 years or older and diagnosed with COVID-19 between January and December, 2020 were enrolled. Serum specimens were collected every three months from 10 days to 12 months after the onset of symptom for determinations of anti-spike IgG and neutralizing antibody titers against SARS-CoV-2 Wuhan strain with D614G mutation, alpha, gamma and delta variants. RESULTS: Of 19 participants, we found a decreasing trend of geometric mean titers of anti-spike IgG from 560.9 to 217 and 92 BAU/mL after a 4-month and a 7-month follow-up, respectively. The anti-spike IgG titers declined more quickly in the ten participants with severe or critical disease than the nine participants with only mild to moderate disease between one month and seven months after SARS-CoV-2 infection (-8.49 vs - 2.34-fold, p < 0.001). The neutralizing activity of the convalescent serum specimens collected from participants recovering from wild-type SARS-CoV-2 infection against different variants was lower, especially against the delta variants (p < 0.01 for each variant with Wuhan strain as reference). CONCLUSION: Acquired immunity from primary infection with SARS-CoV-2 waned within 4-7 months in COVID-19 patients, and neutralizing cross-activities against different SARS-CoV-2 variants were lower compared with those against wild-type strain.
Asunto(s)
COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , Anticuerpos Neutralizantes , Sueroterapia para COVID-19 , Inmunoglobulina G , Anticuerpos AntiviralesRESUMEN
Serological assays are useful in investigating the development of humoral immunity against SARS-CoV-2 in the context of epidemiological studies focusing on the spread of protective immunity. The plaque reduction neutralization test (PRNT) is the gold standard method to assess the titer of protective antibodies in serum samples. However, to provide a result, the PRNT requires several days, skilled operators, and biosafety level 3 laboratories. Therefore, alternative methods are being assessed to establish a relationship between their outcomes and PRNT results. In this work, four different immunoassays (Roche Elecsys® Anti SARS-CoV-2 S, Snibe MAGLUMI® SARS-CoV-2 S-RBD IgG, Snibe MAGLUMI® 2019-nCoV IgG, and EUROIMMUN® SARS-CoV-2 NeutraLISA assays, respectively) have been performed on individuals healed after SARS-CoV-2 infection. The correlation between each assay and the reference method has been explored through linear regression modeling, as well as through the calculation of Pearson's and Spearman's coefficients. Furthermore, the ability of serological tests to discriminate samples with high titers of neutralizing antibodies (>160) has been assessed by ROC curve analyses, Cohen's Kappa coefficient, and positive predictive agreement. The EUROIMMUN® NeutraLISA assay displayed the best correlation with PRNT results (Pearson and Spearman coefficients equal to 0.660 and 0.784, respectively), as well as the ROC curve with the highest accuracy, sensitivity, and specificity (0.857, 0.889, and 0.829, respectively).
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COVID-19 , SARS-CoV-2 , Anticuerpos Neutralizantes , Anticuerpos Antivirales , COVID-19/diagnóstico , Prueba de COVID-19 , Humanos , Inmunoglobulina G , Sensibilidad y Especificidad , Pruebas Serológicas/métodosRESUMEN
Dyskalemias are often seen in children with chronic kidney disease (CKD). While hyperkalemia is common, with an increasing prevalence as glomerular filtration rate declines, hypokalemia may also occur, particularly in children with renal tubular disorders and those on intensive dialysis regimens. Dietary assessment and adjustment of potassium intake is critically important in children with CKD as hyperkalemia can be life-threatening. Manipulation of dietary potassium can be challenging as it may affect the intake of other nutrients and reduce palatability. The Pediatric Renal Nutrition Taskforce (PRNT), an international team of pediatric renal dietitians and pediatric nephrologists, has developed clinical practice recommendations (CPRs) for the dietary management of potassium in children with CKD stages 2-5 and on dialysis (CKD2-5D). We describe the assessment of dietary potassium intake, requirements for potassium in healthy children, and the dietary management of hypo- and hyperkalemia in children with CKD2-5D. Common potassium containing foods are described and approaches to adjusting potassium intake that can be incorporated into everyday practice discussed. Given the poor quality of evidence available, a Delphi survey was conducted to seek consensus from international experts. Statements with a low grade or those that are opinion-based must be carefully considered and adapted to individual patient needs, based on the clinical judgment of the treating physician and dietitian. These CPRs will be regularly audited and updated by the PRNT.
Asunto(s)
Hiperpotasemia , Potasio en la Dieta , Insuficiencia Renal Crónica , Niño , Humanos , Hiperpotasemia/dietoterapia , Hiperpotasemia/etiología , Hiperpotasemia/prevención & control , Diálisis Renal/efectos adversos , Insuficiencia Renal Crónica/complicaciones , Insuficiencia Renal Crónica/dietoterapia , Insuficiencia Renal Crónica/terapiaRESUMEN
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serological assays are urgently needed for rapid diagnosis, contact tracing, and for epidemiological studies. So far, there is limited data on how commercially available tests perform with real patient samples, and if positive tested samples show neutralizing abilities. Focusing on IgG antibodies, we demonstrate the performance of two enzyme-linked immunosorbent assay (ELISA) assays (Euroimmun SARS-CoV-2 IgG and Vircell COVID-19 ELISA IgG) in comparison to one lateral flow assay (FaStep COVID-19 IgG/IgM Rapid Test Device) and two in-house developed assays (immunofluorescence assay [IFA] and plaque reduction neutralization test [PRNT]). We tested follow up serum/plasma samples of individuals polymerase chain reaction-diagnosed with COVID-19. Most of the SARS-CoV-2 samples were from individuals with moderate to the severe clinical course, who required an in-patient hospital stay. For all examined assays, the sensitivity ranged from 58.8 to 76.5% for the early phase of infection (days 5-9) and from 93.8% to 100% for the later period (days 10-18).
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Anticuerpos Antivirales/sangre , COVID-19/diagnóstico , Inmunoglobulina G/sangre , SARS-CoV-2/inmunología , Adulto , COVID-19/sangre , COVID-19/inmunología , COVID-19/virología , Ensayo de Inmunoadsorción Enzimática/normas , Femenino , Técnica del Anticuerpo Fluorescente Indirecta/normas , Hospitalización , Humanos , Masculino , Persona de Mediana Edad , Pruebas de Neutralización/normas , SARS-CoV-2/patogenicidad , Sensibilidad y Especificidad , Índice de Severidad de la Enfermedad , Factores de TiempoRESUMEN
Chikungunya (CHIKV) reemerged in India after a gap of 32 years, in 2005-2006 and has established endemicity in Pune. To assess the degree of CHIKV exposure, we estimated age-stratified prevalence of IgG antibodies to CHIKV in Pune population. This retrospective study utilized age-stratified serum samples collected from 15 wards of Pune in 2017 for dengue (DENV) virus study. Indirect anti-CHIKV-IgG ELISA was developed and used to test 1904 samples. Exposure to CHIKV and DENV was compared in the same population. CHIKV-specific plaque reduction neutralization test (PRNT) was employed to evaluate ELISA positivity and neutralizing potential of anti-CHIKV-IgG antibodies. Indirect ELISA showed 98.5% concordance with commercial ELISA. Seropositivity to CHIKV was 46.4%, one-third children < 15 years being antibody positive. A significant increase (45%, p = 0.026-0.038) was noted at 16-25 years and varied between 48 and 56% until the age 65. In elderly (65 + years), antibody positivity was reduced (41%, p = 0.01). In children, CHIKV-PRNT50 titers increased with age and remained comparable from the age group 11-15 until > 65. Exposure to DENV was higher than CHIKV. Lower exposure of children and elderly could be due to lesser exposure to the vectors. High prevalence of IgG antibodies needs to be addressed while planning vaccine studies for CHIKV.
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Fiebre Chikungunya/epidemiología , Virus Chikungunya/inmunología , Adolescente , Adulto , Factores de Edad , Anciano , Fiebre Chikungunya/sangre , Fiebre Chikungunya/virología , Niño , Preescolar , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Inmunoglobulina G/sangre , India/epidemiología , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Prevalencia , Curva ROC , Estudios Retrospectivos , Sensibilidad y Especificidad , Adulto JovenRESUMEN
Jamestown Canyon virus (JtCV) is an arbovirus and a member of the California serogroup. To our knowledge, all the cases of JtCV have been reported in immunocompetent patients since it was first detected in 1997. We report a case of JtCV encephalitis in a solid organ transplant patient. A 48-year-old woman from Wisconsin had multiple hospital admissions for symptoms of progressive confusion, visual hallucinations, and inability to perform self-care. Initial evaluation was significant for lymphocytes in cerebrospinal fluid (CSF), and multiple infectious and metabolic causes were excluded. Further investigation found JtCV IgM in serum, and CSF. The patient's clinical course was compatible with JtCV encephalitis, and she was treated with ribavirin in addition to reduction of her immunosuppressive medications. She showed gradual and significant improvement in her mental and functional status. JtCV can cause a variety of symptoms that range from a flu-like syndrome to encephalitis. There have been an increased number of reported cases in recent years which is attributed to increased physician awareness and the availability of laboratory testing. Optimal treatment is still not known.
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Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/líquido cefalorraquídeo , Encefalitis de California/diagnóstico , Trasplante de Corazón/efectos adversos , Antivirales/uso terapéutico , Virus de la Encefalitis de California/patogenicidad , Encefalitis de California/tratamiento farmacológico , Encefalitis de California/etiología , Femenino , Humanos , Inmunoglobulina M/sangre , Inmunoglobulina M/líquido cefalorraquídeo , Persona de Mediana Edad , Ribavirina/uso terapéutico , Resultado del TratamientoRESUMEN
Chronic wasting disease (CWD) is caused by abnormal deleterious prion protein (PrPSc), and transmissible spongiform encephalopathy occurs in the Cervidae family. In recent studies, the susceptibility of prion disease has been affected by polymorphisms of the prion gene family. However, the study of the prion-related protein gene (PRNT) is rare, and the DNA sequence of this gene was not fully reported in all Cervidae families. In the present study, we amplified and first identified PRNT DNA sequences in the Cervidae family, including red deer, elk, sika deer and Korean water deer, using polymerase chain reaction (PCR). We aligned nucleotide sequences of the PRNT gene and the amino acid sequences of prion-related protein (Prt) protein among several species. In addition, we performed phylogenetic analysis to measure the evolutionary relationships of the PRNT gene in the Cervidae family. Furthermore, we performed homology modeling of the Prt protein using SWISS-MODEL and compared the structure of Prt protein between sheep and the Cervidae family using the Swiss-PdbViewer program. We obtained much longer PRNT sequences of red deer compared to the PRNT gene sequence registered in GenBank. Korean water deer denoted more close evolutionary distances with goats and cattle than the Cervidae family. We found 6 Cervidae family-specific amino acids by the alignment of Prt amino acid sequences. There are significantly different distributions of hydrogen bonds and the atomic distance of the N-terminal tail and C-terminal tail between sheep and the Cervidae family. We also detected the mRNA expression of PRNT gene in 3 tissues investigated. To our knowledge, this report is the first genetic study of the PRNT gene in the Cervidae family.
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Ciervos/genética , Priones/genética , Enfermedad Debilitante Crónica/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Expresión Génica , Modelos Moleculares , Priones/química , Conformación Proteica , ARN Mensajero/genéticaRESUMEN
BACKGROUND & OBJECTIVES: The global pandemic caused by SARS-CoV-2 virus has challenged public health system worldwide due to the unavailability of approved preventive and therapeutic options. Identification of neutralizing antibodies (NAb) and understanding their role is important. However, the data on kinetics of NAb response among COVID-19 patients are unclear. To understand the NAb response in COVID-19 patients, we compared the findings of microneutralization test (MNT) and plaque reduction neutralization test (PRNT) for the SARS-CoV-2. Further, the kinetics of NAb response among COVID-19 patients was assessed. METHODS: A total of 343 blood samples (89 positive, 58 negative for SARS-CoV-2 and 17 cross-reactive and 179 serum from healthy individuals) were collected and tested by MNT and PRNT. SARS-CoV-2 virus was prepared by propagating the virus in Vero CCL-81 cells. The intra-class correlation was calculated to assess the correlation between MNT and PRNT. The neutralizing endpoint as the reduction in the number of plaque count by 90 per cent (PRNT90) was also calculated. RESULTS: The analysis of MNT and PRNT quantitative results indicated that the intra-class correlation was 0.520. Of the 89 confirmed COVID-19 patients, 64 (71.9%) showed NAb response. INTERPRETATION & CONCLUSIONS: The results of MNT and PRNT were specific with no cross-reactivity. In the early stages of infection, the NAb response was observed with variable antibody kinetics. The neutralization assays can be used for titration of NAb in recovered/vaccinated or infected COVID-19 patients.
Asunto(s)
Anticuerpos Neutralizantes/aislamiento & purificación , Infecciones por Coronavirus/sangre , Pruebas de Neutralización , Pandemias , Neumonía Viral/sangre , Adolescente , Adulto , Animales , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/sangre , Betacoronavirus/inmunología , Betacoronavirus/patogenicidad , COVID-19 , Niño , Chlorocebus aethiops/inmunología , Infecciones por Coronavirus/epidemiología , Infecciones por Coronavirus/inmunología , Infecciones por Coronavirus/virología , Femenino , Humanos , Inmunoglobulina G/sangre , Masculino , Persona de Mediana Edad , Neumonía Viral/epidemiología , Neumonía Viral/inmunología , Neumonía Viral/virología , SARS-CoV-2 , Células Vero/inmunología , Adulto JovenRESUMEN
We tested a sample of 234 wild long-tailed macaques (Macaca fascicularis) trapped in Peninsular Malaysia in 2009, 2010, and 2016 for Zika virus RNA and antibodies. None were positive for RNA, and only 1.3% were seropositive for neutralizing antibodies. Long-tailed macaques are unlikely to be reservoirs for Zika virus in Malaysia.
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Enfermedades de los Monos/epidemiología , Enfermedades de los Monos/virología , Infección por el Virus Zika/veterinaria , Virus Zika , Animales , Animales Salvajes , Macaca fascicularis , Malasia/epidemiología , ARN Viral , Serogrupo , Virus Zika/clasificación , Virus Zika/genéticaRESUMEN
The increasing risk of Rift Valley fever virus (RVFV) infection as a global veterinary and public health threat demands the development of safe and accurate diagnostic tests. The aim of this study was to assess the suitability of a baculovirus expression system to produce recombinant RVFV nucleoprotein (N) for use as serodiagnostic antigen in an indirect enzyme-linked immunosorbent assay (ELISA). The ability of the recombinant N antigen to detect RVFV antibody responses was evaluated in ELISA format using antisera from sheep and cattle experimentally infected with two genetically distinct wild-type RVFV strains and sera from indigenous sheep and goat populations exposed to natural RVFV field infection in The Gambia. The recombinant N exhibited specific reactivity with the N-specific monoclonal antibody and various hyperimmune serum samples from ruminants. The indirect ELISA detected N-specific antibody responses in animals with 100% sensitivity compared to the plaque reduction neutralization test (6 to 21 days postinfection) and with 97% and 100% specificity in sheep and cattle, respectively. There was a high level of correlation between the indirect N ELISA and the virus neutralization test for sheep sera (R2 = 0.75; 95% confidence interval [CI] = 0.73 to 0.92) and cattle sera (R2 = 0.80; 95% CI = 0.67 to 0.97); in addition, the N-specific ELISA detected RVFV seroprevalence levels of 26.1% and 54.3% in indigenous sheep and goats, respectively, in The Gambia. The high specificity and correlation with the virus neutralization test support the idea of the feasibility of using the recombinant baculovirus-expressed RVFV N-based indirect ELISA to assess RVFV seroprevalence in livestock in areas of endemicity and nonendemicity.
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Antígenos Virales/inmunología , Ensayo de Inmunoadsorción Enzimática , Nucleoproteínas/inmunología , Proteínas Recombinantes/inmunología , Fiebre del Valle del Rift/diagnóstico , Fiebre del Valle del Rift/inmunología , Virus de la Fiebre del Valle del Rift/inmunología , Animales , Anticuerpos Antivirales/inmunología , Baculoviridae/genética , Vectores Genéticos/genética , Inmunoglobulina G/inmunología , Ganado , Pruebas de Neutralización , Nucleoproteínas/genética , Proteínas Recombinantes/genética , Sensibilidad y Especificidad , Ovinos , Enfermedades de las Ovejas/diagnóstico , Enfermedades de las Ovejas/inmunologíaRESUMEN
We assessed Zika virus seroprevalence among healthy 1-4-year-old children using a serum sample collection assembled in 2014 representing 30 urban sites across Indonesia. Of 662 samples, 9.1% were Zika virus seropositive, suggesting widespread recent Zika virus transmission and immunity. Larger studies are needed to better determine endemicity in Indonesia.
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Brotes de Enfermedades/prevención & control , Infección por el Virus Zika/epidemiología , Virus Zika/aislamiento & purificación , Anticuerpos Antivirales/sangre , Salud Infantil , Preescolar , Estudios de Cohortes , Estudios Transversales , Femenino , Humanos , Indonesia/epidemiología , Lactante , Masculino , Estudios Seroepidemiológicos , Virus Zika/inmunología , Infección por el Virus Zika/sangre , Infección por el Virus Zika/etiología , Infección por el Virus Zika/virologíaRESUMEN
Recent worldwide outbreaks of Zika virus (ZIKV) infection and the lack of an approved vaccine raise serious concerns regarding preparedness to combat this emerging virus. We used a virus-like particle (VLP)-based approach to develop a vaccine and a microneutralization assay for ZIKV. A synthetic capsid-premembrane-envelope (C-prM-E) gene construct of ZIKV was used to generate reporter virus particles (RVPs) that package a green fluorescent protein (GFP) reporter-expressing West Nile virus (WNV) replicon. The assay was adapted to a 96-well format, similar to the plaque reduction neutralization test (PRNT), and showed high reproducibility with specific detection of ZIKV neutralizing antibodies. Furthermore, C-prM-E and prM-E VLPs were tested as vaccine candidates in mice and compared to DNA vaccination. While the ZIKV prM-E construct alone was sufficient for generating VLPs, efficient VLP production from the C-prM-E construct could be achieved in the presence of the WNV NS2B-3 protease, which cleaves C from prM, allowing virus release. Immunization studies in mice showed that VLPs generated higher neutralizing antibody titers than those with the DNA vaccines, with C-prM-E VLPs giving slightly higher titers than those with prM-E VLPs. The superiority of C-prM-E VLPs suggests that inclusion of capsid may have benefits for ZIKV and other flaviviral VLP vaccines. To facilitate the VLP platform, we generated a stable cell line expressing high levels of ZIKV prM-E proteins that constitutively produce VLPs as well as a cell line expressing ZIKV C-prM-E proteins for RVP production. While several vaccine platforms have been proposed for ZIKV, this study describes a safe, effective, and economical VLP-based vaccine against ZIKV.IMPORTANCE To address the growing Zika virus epidemic, we undertook this study with two objectives: first, to develop a safe, effective, and economical vaccine for ZIKV, and second, to develop a rapid and versatile assay to detect the anti-ZIKV immune response. We generated a cell line stably expressing ZIKV prM-E that produces large amounts of VLPs in the supernatant and a ZIKV C-prM-E cell line that produces reporter virus particles upon transfection with a GFP replicon plasmid. The prM-E VLPs induced a strong neutralizing antibody response in mice that was better when the capsid was included. VLP-based vaccines showed significantly better neutralizing antibody responses than those with their DNA counterparts. The RVP-based microneutralization assay worked similarly to the PRNT assay, with a rapid GFP readout in a 96-well format. Our VLP-based platform provides a source for a ZIKV vaccine and diagnosis that can rapidly be adapted to current outbreaks.
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Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , Pruebas de Neutralización , Vacunas de Partículas Similares a Virus/inmunología , Vacunas Virales/inmunología , Infección por el Virus Zika/prevención & control , Virus Zika/inmunología , Animales , Anticuerpos Neutralizantes/biosíntesis , Anticuerpos Antivirales/biosíntesis , Proteínas Fluorescentes Verdes/genética , Ratones , Reproducibilidad de los Resultados , Vacunas de ADN/administración & dosificación , Vacunas de ADN/inmunología , Vacunas de Partículas Similares a Virus/administración & dosificación , Vacunas de Partículas Similares a Virus/efectos adversos , Vacunas de Partículas Similares a Virus/genética , Vacunas Virales/administración & dosificación , Vacunas Virales/efectos adversos , Vacunas Virales/economía , Virus del Nilo Occidental/genética , Virus Zika/aislamiento & purificación , Infección por el Virus Zika/inmunologíaRESUMEN
A collection of 3069 human sera collected in the area of the municipality of Modena, Emilia Romagna, Italy, was retrospectively investigated for specific antibodies against Usutu (USUV) and West Nile viruses (WNV). All the samples resulting positive using a preliminary screening test were analyzed with the plaque reduction neutralization test. Overall, 24 sera were confirmed as positive for USUV (0.78%) and 13 for WNV (0.42%). The results suggest that in 2012, USUV was circulating more than WNV in North-eastern Italy.
Asunto(s)
Anticuerpos Antivirales/sangre , Flavivirus/inmunología , Virus del Nilo Occidental/inmunología , Anticuerpos Neutralizantes/sangre , Donantes de Sangre , Humanos , Italia/epidemiología , Pruebas de Neutralización , Estudios Retrospectivos , Estudios SeroepidemiológicosRESUMEN
BACKGROUND: Zika Virus (ZIKV), member of Flaviviridae family and Flavivirus genus, has recently emerged as international public health emergency after its association with neonatal microcephaly cases. Clinical diagnosis hindrance involves symptom similarities produced by other arbovirus infections, therefore laboratory confirmation is of paramount importance. DISCUSSION: The most reliable test available is based on ZIKV RNA detection from body fluid samples. However, short viremia window periods and asymptomatic infections diminish the success rate for RT-PCR positivity. Beyond molecular detection, all serology tests in areas where other Flavivirus circulates proved to be a difficult task due to the broad range of cross-reactivity, especially with dengue pre-exposed individuals. CONCLUSION: Altogether, lack of serological diagnostic tools brings limitations to any retrospective evaluation. Those studies are central in the context of congenital infection that could occur asymptomatically and mask prevalence and risk rates.
Asunto(s)
Infección por el Virus Zika/diagnóstico , Adulto , Anticuerpos Antivirales/análisis , Líquidos Corporales/química , Humanos , Lactante , Recién Nacido , Microcefalia , Patología Molecular , Infección por el Virus Zika/sangreRESUMEN
Zika virus (ZIKV) is an emerging pathogen that causes congenital infections which may result in birth defects, such as microcephaly. Currently, no approved treatment or vaccination is available. ZIKV can be readily detected in cell culture where virally infected cells are normally stained by specific antibodies. As ZIKV regularly causes a cytopathic effect, we were wondering whether this viral property can be used to quantitatively determine viral infectivity. We here describe the use of an 3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2H-tetrazolium bromide-(MTT)-based cell viability assay that allows to determine ZIKV-induced cell death. We show that this colorimetric assay quantifies ZIKV infection over a broad range of viral dilutions in both monkey and human cells. It allows to determine inhibitory activities of antivirals that block ZIKV or to define the neutralizing antibody titers of ZIKV antisera. This MTT-based ZIKV detection assay can be evaluated by naked eye or computational tools, has a broad linear range, does not require large equipment or costly reagents, and thus represents a promising alternative to antibody-based assays, in particular in resource-poor settings. We propose to use this simple, fast, and cheap method for quantification of ZIKV neutralizing antibodies and testing of antiviral compounds.