中国生物工程杂志

Mixed anhydride(MA) was used to conjugate ractopamine (RAC) to bovine serum albumin(BSA) and obtained artificial antigen BSA-RAC identified by UV and SDS-PAGE. Balb/c mice were immunized with BSA-RAC and hybridoma lines that secrete RAC monoclonal antibody(mAb) were generated with cell fusion. A ciELISA kit for detection of RAC (RAC-Kit) was developed with RAC mAb and its traits were tested. The results indicated that BSA-RAC was synthesized successfully and its conjugation ratio of RAC to BSA was about 24.5∶1. Three hybridoma lines were filtered and the best one was 4D8, its affinity constant (Ka) was 1.65×1010L/mol. The detection limit of RAC-Kit was 0.5ng/ml and its detection range was 0.5 to 151ng/ml. The recoveries of RAC spiked in feed were 87.2% and in swine urine were 89.4%. The precision and accuracy of the assay as determined by inter-assay and intra-assay coefficient variation were below 15%. It had 22.3% cross-reactivity (CR%) to dobutamine and little or no CR to other compounds. The validity of RAC-Kit in 4℃ was above 180d.