Establishment Of Latex Agglutination Test To Detect Bovine Tuberculosis Antibodies And The Clinic Application

Tuberculosis(TB) is a chronic respiratory infectious disease which imperils the health of human beings. By the estimate of WHO, there are about 2 billion people affected in the whole world, 5%-10% of them develop active pulmonary tuberculosis, the number of new infected people is as high as 8-10 million, about 3 million died one year.Mycobacterium bovis results in bovine Tuberculosis, a chronic consumptive zoonosis which can infect people, domestic animals and wild animals. It is considered as B type infectious disease by OIE. Bovine Tuberculosis, as well as Brucellosis are referred as "Two Disease" of cows, causing great economic loss in cow industry and a continuing threat to public health.China implements a policy of "Quarantine-kill" on cows infected by Mycobacterium bovis. Therefore, sensitive, rapid, and specific detection method is the most important premise to perform the policy effectively. The current authorized detection method tuberculin skin test (TST) often get false positive results caused by the common components from other mycobacterium. This study was aimed to establish a novel method which is more specific and sensative than TST.1. Cloning and expression mpb70 of Mycobacterium bovisWe cloned the coding region of MPB70 gene for Mycobacterium bovis, constructed the prokaryotic expression vector, expressed and purifed the protein.2. Establishment of Latex Agglutination TestThe Latex Agglutination (LAT) Test to detect bovine Tuberculosis was established. The carboxyl polystyrene of latex beads were used to link covalently to the protein MPB70. The coupled beads can detect the specific antibody in sera towards MPB70 of Mycobacterium bovis. By covalently coupling to the target protein and beads, we solve many problems faced by common latex beads, such as the less amount of sensitized protein, unstable, weak connection between the protein and the beads. Meanwhile, taking MPB70 as the coupled antigen instead of the whole bacteria in this LAT has a higher biosafety. It has high sensitivity, specificity and repeatability.3. Clinical application of Latex Agglutination TestA total of 131 sera from Wu Han A and B cattle farms were detected clinically with LAT, as well as other availe methods including TST and ELISA. During the 70 sera from farm A, the agreement between MPB70-LAT with TST, MPB70-IHA and MPB70-ELISA...