[Polyclonal antibody production and immunoassay development for detection of beta-lactamase in milk].

OBJECTIVE: To produce polyclonal antibody with affinity against several types of beta-lactamase and develop an indirect competitive ELISA for detection of beta-lactamase in milk. METHODS: A mixture of beta-lactamase was used as immunogen for animal immunization to produce polyclonal antibody. After purification polyclonal produce animal immunization to characterization, the obtained antibody was employed to establish an ELISA method for beta-lactamase determination. RESULTS: The polyclonal antibody was acquired, with the concentration of 17.9-18.9 mg/ml in antiserum. The molecular weights were 55, 25 and 160 kD for heavy chain, light chain and the whole antibody, respectively. The developed ELISA method showed the LOD 0.2 ng/ml and the linear range of 0.2-200 ng/ml. The recoveries ranged from 80% to 115%, with RSD bellow 20%. CONCLUSION: With the polyclonal antibody, the proposed indirect competitive ELISA method was successfully applied to determine beta-lactamase in milk.