Study Of Competitive ELISA(C-ELISA) Kit For Antibody Of Porcine Respiratory And Productive Syndrome (PRRS)

3 hybridized cell strains are developed by cell fusion technique and screened by indirect ELISA and blocked ELISA with PRRS viral antigen and specific antibody. PRRS N protein gene is cloned into PET30b plasmid and expressed in BL21, C-ELISA system to test PRRS antibody is established by using the monoclonal antibody and expressed protein as main reagent. The cut off value of C-ELISA is determined, Sensitivity and specificity of the system is also studied. The result of this study shows that the cut off value is 30%. The result of the C-ELISA kit and the IDEXX indirect ELISA kit to test samples sera of 5Dpi, 12Dpi, and 29Dpi challenged swine shows that the C-ELISA kit is more sensitive than the IDEXX indirect ELISA, PRRS antibodies were fund in 5dpi sera by this kit, but no positive samples are fund by the indirect ELISA kit in same samples. Test of positive sera of other swine diseases by this C-ELISA kit shows no cross reactivity, The specificity of the C-ELISA is 100%, The consensus between the two ELISA kit for clinical samples is about 93%, The characteristics of the C-ELISA kit to test European PRRS trains related antibody is not studied, and can not separated the antibody of American and European strains. An application for new veterinary drug certification of this Kit has been submitted to the authority competence, and has passed the first stage audition now.