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An abrupt decrease in egg production and quality in laying hens can be brought on by the avian adenovirus known as the egg drop syndrome virus (EDSV). So far, there are no efficient commercial diagnostic approaches for EDSV. In the present study, we first purified two monoclonal antibodies (mAbs 5G4 and 6G6) specifically against the EDSV fibre protein. The mAb 5G4 was then employed as capture antibody. Additionally, the detection antibody 6G6 (HRP-6G6) was conjugated with horseradish peroxidase. Consequently, based on these two mAbs, we developed a sandwich enzyme-linked immunosorbent assay (ELISA) for EDSV detection. Specificity evaluation demonstrated that only EDSV gave a positive result while other avian viruses showed negative results. Sensitivity investigation showed that the limit of detection of EDSV was 102.9 TCID50/ml and the limit of detection of the purified His-Fiber was 5 ng/ml. Furthermore, the screening of samples from infected chickens showed that this method was very effective and could be applied to the detection of EDSV in infected samples. In summary, the sandwich enzyme-linked immunosorbent assay developed here provides an efficient, sensitive, and large-scale method for the specific diagnosis of EDSV. A sandwich ELISA was developed to detect EDSV using the mAbs 5G4 and HRP-6G6. The sandwich ELISA maintained high specificity and sensitivity. The sandwich ELISA had equivalent consistency with real-time PCR assay. [ABSTRACT FROM AUTHOR]

Wheat gliadin is thought to be the main cause of wheat allergy leading to celiac disease. In this study, we reported an electrochemical immunosensor based on AuNPs/Zn/Ni-ZIF-8-800@graphene for simple, efficient, and sensitive detection of gliadin. A monoclonal antibody against gliadin were prepared by hybridoma technique. Zn/Ni-ZIF-8-800 with high stability was prepared by using zinc–nickel bimetallic organic framework MOFs, and graphene and gold nanoparticles with large surface area and excellent conductivity were introduced. Chitosan was used as a binder to fixed the composite on the surface of glassy carbon electrode. The fabricated materials and the corresponding sensors were comprehensively characterized by X-ray diffractometer, scanning electron microscope, transmission electron microscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller, and cyclic voltammetry analyses. Under the optimal conditions, the linear range of the electrochemical immunosensor was 0.1–100 μg mL−1, and the detection limit was 0.950 μg mL−1. In addition, the fabricated sensor exhibited high selectivity and long-term stability. The recovery test showed that the prepared sensor was suitable for the detection of gliadin in real food and feed, exhibiting great promising of the developed sensor in practical application. [ABSTRACT FROM AUTHOR]

Carprofen (CAR) is a non-steroidal anti-inflammatory drug commonly used to treat various musculoskeletal diseases and infections in food animals. While CAR residues in food animal tissues caused by veterinary medicine abuse are a potential danger to human health. In this study, a high-affinity monoclonal antibody (mAb) against CAR was prepared, and then an immunochromatographic strip for rapidly screening CAR in bovine muscle was developed to help enforce regulatory compliance. The visual detection limit (cut-off value) by the naked eye of the fabricated test strip was 12.5 ng g−1. Scanning by the strip reader, the IC50 of the test strip was calculated as 1.743 ng g−1, and the limit of detection (LOD, IC10) was 0.283 ng g−1. The proposed method provided an efficient tool for monitoring CAR in bovine muscle. Meantime, our work suggested great potential for the analysis of CAR residues in other food matrixes. [ABSTRACT FROM AUTHOR]

BACKGROUND: Nitroxynil (NIT) is a veterinary drug against hepatic fluke disease for food‐producing cattle and sheep. NIT has a long half‐life time in animals since it is highly bound to plasma protein. Therefore NIT possibly remains in animal edible tissues or milk due to drug abuse. In this study, a specific murine monoclonal antibody (mAb) against NIT was prepared and an immunochromatographic strip assay based on the mAb was developed for screening NIT in milk. RESULTS: The affinity constant of the anti‐NIT mAb was 2.93 × 1010 and the anti‐NIT mAb had almost no cross‐reactivity with other analogs, so that it showed good specificity. The cutoff value of this test strip was considered to be 50 ng mL−1 by the naked eye. When detected by the strip reader, the half maximum inhibition concentration (IC50) of the immunoassay strip was calculated to be 5.716 ng mL−1 and the limit of detection (LOD) was 1.146 ng mL−1. Intra‐assay recoveries from 88.80 to 97.13% were obtained, with the highest coefficient of variation (CV) at 9.01%; inter‐assay recoveries ranged from 84.60 to 106.87%, with the highest CV at 9.93%. CONCLUSION: The operative procedure of the proposed method can be completed within 10 min. The strip developed in this study was a practical tool for rapid semiquantitative and quantitative detection of NIT in milk. This study suggested great potential for analytically monitoring NIT in other food samples. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The nucleocapsid (N) protein is a suitable candidate for early diagnosis of porcine epidemic diarrhea virus (PEDV). Here, we identified the linear B-cell epitopes of the PEDV N-protein by integrating a computational-experimental framework and constructed three-dimensional (3D) structure model of the N protein using the ColabFold program in Google Colaboratory. Furthermore, we prepared the monoclonal antibodies against the predicted epitopes and recombinant N protein, respectively, and selected pairing mAbs (named 9C4 and 3C5) to develop a double-antibody sandwich immunochromatographic test strip using CdSe/ZnS quantum dots (QDs)-labelled 9C4 and 3C5 as capture and detection antibodies, respectively. This strip can specifically detect PEDV within 10 min with a detection limit of less than 6.25 × 103 TCID 50 /mL. In comparison with RT-PCR for testing 90 clinical samples, the relative sensitivity and specificity of the strip were found to be 98.0% and 100%, respectively, with a concordance rate of 98.9% and a kappa value of 0.978, indicating that QDs-ICTS is a reliable method for the application of PEDV detection in clinical samples. • Discovery of novel B-cell liner epitopes in the N protein of PEDV in silico. • Preparation of mAbs against predicted epitopes and recombination N protein of PEDV. • A quantum dot-based immunochromatographic test strip was developed to detect PEDV. [ABSTRACT FROM AUTHOR]

• A highly sensitive monoclonal antibody (mAb) against bacitracin was produced. • An immunoassay strip was developed for monitoring BAC in milk. • This strip was accurate and reliable based on the results of recovery test. In this study, a murine monoclonal antibody (mAb) of 6D2-G10 against bacitracin zinc (BAC) was produced and applied to an immunochromatographic strip (ICS) for the initial detection of BAC in milk. The ICS with a cut-off value of 25 ng/mL could be perceived by the naked eye within 10 min. With the assist of the strip reader, the limit of detection (LOD) was measured as 0.82 ng/mL, the half-maximal inhibitory concentration (IC 50) was recorded as 3.16 ng/mL, and the linear detection range was from 0.97 to 10.30 ng/mL. The recoveries ranged from 87.7% to 96.0% with the highest coefficient of variation (CV) of 9.1% in the intra-assay and from 84.3% to 90.2% with the highest CV of 10.7% in the inter-assay. In short, the established ICS provided a serviceable analytical tool for qualitatively and quantitatively monitoring BAC in milk. [ABSTRACT FROM AUTHOR]