| Maedi-Visna virus(MVV)is the causative agent of Maedi-Visna disease(MVD)in sheep.MVD is a chronic viral disease.Currently,there is a lack of effective treatment for MVD.And there is no effective vaccine to prevent the sheep infected with the virus.Movement restriction,isolation and culling are the only measures for infected MVV-infected sheep.Therefore,early detection of infected sheep is particularly important.In order to achieve the purpose of early detection,a diagnostic method with high sensitivity,strong specificity,suitable for batch field detection,simple and quick operation is needed.Therefore,the following experiments were carried out in this study :In this study,the prokaryotic expression system containing the recombinant plasmid of p Easy-E1-CA-TM constructed by Chen Sixu in our laboratory was used to obtain the recombinant CA-TM fusion protein through prokaryotic expression and purification,and the recombinant CA-TM fusion protein was used as the detection line coated antigen to establish a rapid detection method of Maedi-Visna virus antibody by colloid gold immunochromatography.The specificity,sensitivity,repeatability and clinical application were evaluated.This experiment successfully expressed,purified and obtained the recombinant CA-TM fusion protein.A colloidal gold immunochromatography method for rapid detection of Medy-Vesna virus antibodies was established.Specificity test results showed that the strip was specific to MVV positive serum,and could specifically identify MVV CA protein antibody and TM protein antibody produced in infected animals.Sensitivity test results showed that the test strip could detect MVV-positive serum at 2400 times dilution.The reproducibility test results showed that the same batch of test strips were used for parallel detection of 7 sera for three times,and the detection results were consistent.Three different batches of test strips were used to detect 5 sera,and the test results were consistent,indicating good repeatability within and between batches of test strips.The stability test results show that the test strip still has good detection performance and stability after being sealed in room temperature and protected from light for 6 months.The colloidal gold detection method established in this study was compared with ID Screen MVV/CAEV Indirect ELISA diagnostic kit to compare the serum samples of 40 suspected cases collected from sick sheep that have been tracked by our research group for a long time.The results showed that the colloidal gold detection method has detected 17 serum samples positive for MVV antibody.There were 23 negative sera,16 positive sera and 24 negative sera detected by the ID Screen MVV/CAEV Indirect kit.By comparison,the colloidal gold immunochromatography method established in this study has an Indirect positive and negative coincidence rate of100%,95.83%,and 97.5% respectively with the ID Screen MVV/CAEV kit.In summary,this experiment successfully established a rapid detection method for the antibody colloidal gold immunochromatography of the Maedi-Visna virus.This method avoids the influence of inaccurate serological detection caused by serum conversion.The test strip developed by this method has good performance and is easy to store.It is suitable for on-site rapid detection and batch detection,and the results can be distinguished by the naked eye without professional instruments.It is of great significance for the monitoring,prevention and control of MVD,and provides a new detection scheme for the purification of MVD in Inner Mongolia. |
