RESUMEN
Currently, foot-and-mouth disease (FMD) vaccine purity is tested in cattle to detect antibodies against the non-structural protein (NSP) after repeated immunization with the final vaccine product. In case of vaccine failure, the manufacturing company would suffer significant economic loss. To prevent such unfortunate losses with the final vaccine product, in vitro testing is required to quantitate an NSP antigen during the manufacturing process prior to animal experiments. A novel lateral-flow assay device was developed using a monoclonal antibody (MAb) against the 3B NSP. To determine the minimal amount of NSP required to elicit antibodies in livestock, goats were immunized several times with various concentrations of either the recombinant 3AB (rec.3AB) protein or FMD virus culture supernatant. Antibodies against 3AB were elicited after a second immunization with 10.6â¯ng to 42.5â¯ng of rec.3AB and a third immunization with a 10-fold diluted FMD virus culture supernatant in goats. The lateral-flow assay device detected the minimal amount of rec.3AB and native NSP in FMD virus culture supernatant required to induce NSP antibodies in goats. The in vitro assay device is simple and economical, provides rapid results, and should be useful for FMD vaccine-manufacturing companies prior to conducting animal experiments to test the vaccine purity.
Asunto(s)
Anticuerpos Antivirales/sangre , Fiebre Aftosa/prevención & control , Vacunación/veterinaria , Proteínas no Estructurales Virales/inmunología , Vacunas Virales/normas , Experimentación Animal , Animales , Anticuerpos Monoclonales/inmunología , Medios de Cultivo , Virus de la Fiebre Aftosa , Cabras , Inmunoensayo , Ganado/inmunología , Masculino , Proteínas Recombinantes/inmunología , Vacunas Virales/inmunologíaRESUMEN
African swine fever is one of the most dangerous diseases of swine. We confirmed the 2019 outbreak in Vietnam by real-time reverse transcription PCR. The causative strain belonged to p72 genotype II and was 100% identical with viruses isolated in China (2018) and Georgia (2007). International prevention and control collaboration is needed.
Asunto(s)
Fiebre Porcina Africana/epidemiología , Fiebre Porcina Africana/historia , Fiebre Porcina Africana/virología , Animales , Asfarviridae/clasificación , Asfarviridae/genética , ADN Viral , Brotes de Enfermedades , Genes Virales , Genotipo , Secuenciación de Nucleótidos de Alto Rendimiento , Historia del Siglo XXI , Filogenia , Análisis de Secuencia de ADN , PorcinosRESUMEN
Porcine reproductive and respiratory syndrome (PRRS) is recognized as one of the most important infectious diseases causing serious economic loss in the swine industry worldwide. Due to its increasing genetic diversity, a rapid and accurate diagnosis is critical for PRRS control. The immunochromatographic strip test (ICST) is a rapid and convenient type of immunoassay. In this study, an on-site immunochromatographic assay-based diagnostic method was developed for detection of PRRS virus (PRRSV)-specific antibodies. The method utilized colloidal gold nanoparticle-labeled dual-type nucleocapsid proteins encoded by open reading frame 7. We evaluated 991 field samples from pig farms and 66 serum samples from experimentally PRRSV-inoculated pigs. Based on true PRRSV-specific antibody-positive or -negative sera determined by immunofluorescence assay and IgM enzyme-linked immunosorbent assay (ELISA), the specificity and sensitivity of the ICST were 97.5% and 91.1%, respectively, similar to those of a commercial ELISA (IDEXX PRRS X3 Ab). More importantly, the ICST was completed within 15 min and could detect the PRRSV-specific antibody at an earlier stage of infection (3-7 days) than that of ELISA (7+ days). The results demonstrate that the developed ICST has great potential as an on-farm diagnostic method, providing excellent diagnostic performance in a quick and convenient manner.
Asunto(s)
Cromatografía de Afinidad/veterinaria , Oro Coloide/química , Nanopartículas del Metal/química , Proteínas de la Nucleocápside/aislamiento & purificación , Síndrome Respiratorio y de la Reproducción Porcina/diagnóstico , Virus del Síndrome Respiratorio y Reproductivo Porcino/aislamiento & purificación , Animales , Síndrome Respiratorio y de la Reproducción Porcina/virología , PorcinosRESUMEN
Two sialylated human milk oligosaccharides (SHMOs) 3'-sialyllactose (3'-SL) and 6'-sialyllactose (6'-SL) were accessed for their possible antiviral activity against six different subtypes of thirteen avian influenza (AI) viruses in vitro. 3'-SL exhibited promising antiviral activity against almost all subtypes of tested AI viruses in hemagglutination inhibition assay, whereas 6'-SL showed activity against few selected H1N1, H1N2, and H3N2 subtype strains. 3'-SL has minimum inhibitory concentration values of 15.62 mM or less in more than half of the viruses examined. 3'-SL also showed effective inactivation of H9N2 Korea isolate (A/Chicken/Korea/MS96/1996) at 12.5 mM concentration in Madin Darby Canine Kidney (MDCK) cell line. Thus, 3'-SL was further studied for in vivo study against H9N2 virus in pathogen free chicken experiment models. In vivo study exhibited improved clinical symptoms on H9N2 infected chickens when treated with 3'-SL. Moreover, treating chickens with 3'-SL resulted in complete elimination of H9N2 viruses within 24 h of virus infection (0.8 HAU of H9N2). Indirect ELISA assay confirmed complete wash-out of H9N2 viruses from the colon after neutralization by 3'-SL without entering the blood stream. These in vivo results open up possible applications of 3'-SL for the prevention of AI virus infections in birds by a simple cleansing mechanism.
Asunto(s)
Antivirales/farmacología , Subtipo H9N2 del Virus de la Influenza A/efectos de los fármacos , Lactosa/análogos & derivados , Leche Humana/química , Oligosacáridos/farmacología , Animales , Pollos , Perros , Humanos , Lactosa/farmacología , Células de Riñón Canino Madin Darby , Modelos Animales , República de CoreaRESUMEN
Infection of cattle with bovine leukemia virus (BLV) has been observed and reported worldwide, including in Korea. The onsite identification of infected cattle would help decreasing and eradicating BLV infections on farms. Here, we present a new immunochromatographic assay that employs monoclonal antibodies (MAbs) for the detection of antibodies against BLV in the field. BLV envelope glycoprotein (gp)51 was expressed in E. coli, and MAbs against recombinant BLV gp51 were generated for the development of an immunochromatographic assay to detect BLV antibodies in cattle. The sensitivity and specificity of the assay were determined by comparing these results with those obtained from a standard enzyme linked immunosorbent assay (ELISA). A total of 160 bovine sera were used to evaluate the new immunochromatographic assay. Using ELISA as a reference standard, the relative specificity and sensitivity of this assay were determined to be 94.7% and 98%, respectively. Because of its high sensitivity and specificity, this BLV antibody detection assay would be suitable for the onsite identification of BLV infection in the field.
Asunto(s)
Anticuerpos Monoclonales/sangre , Anticuerpos Antivirales/sangre , Cromatografía de Afinidad/veterinaria , Leucosis Bovina Enzoótica/diagnóstico , Virus de la Leucemia Bovina/inmunología , Tamizaje Masivo/veterinaria , Animales , Bovinos , Leucosis Bovina Enzoótica/virología , Proyectos Piloto , República de CoreaRESUMEN
Porcine epidemic diarrhea virus (PEDV) causes acute diarrhea and dehydration in sucking piglets and has a high mortality rate. An immunochromatography (IC) assay, known as a lateral flow test, is a simple device intended to detect the presence of target pathogens. Here, we developed an IC assay that detected PEDV antigens with 96.0% (218/227) sensitivity and 98.5% (262/266) specificity when compared with real-time reverse transcriptase (RT)-PCR using FAM-labeled probes based on sequences from nucleocapsid genes. The detection limits of the real-time RT-PCR and IC assays were 1×10(2) and 1×10(3) copies, respectively. The IC assay developed herein did not detect non-specific reactions with other viral or bacterial pathogens, and the assay could be stored at 4°C or room temperature for 15 months without affecting its efficacy. Thus, the IC assay may result in improved PED detection and control on farms, and is a viable alternative to current diagnostic tools for PEDV.