Study Of Fluorescence Labeled Immunochromatographic Strip For The Detection Of Bovine Brucellosis

Brucellosis is a widely prevalent and serious zoonotic disease. In recent years, the number of clinical cases that infected with brucellosis increased obviously worldwide, which brought serious impact on the livestock breeding industry and led to a serious public health problem. The fast and accurate diagnosis of brucellosis can provide early and effective information for the prevention and treatment of disease. In view of this, it is necessary to establish a rapid and effective detection method of brucellosis.In the study, firstly, the OMP19, OMP22 and OMP28 genes of Brucella bovine, were selected for protein expression. Secondly, the pCold-TF/OMP 19, pCold-TF/ OMP22 and pCold-TF/OMP28 recombinant plasmid was transformed into E. coli BL21 (DE3) cOMPetent cells for prokaryotic expression. Finally, three kinds of proteins were obtained after purification by affinity chromatography respectively. The soluble recombinant proteins related to the above mentioned three genes were obtained and purified and the ELISA assay was used to verify their activity. Results showed these recombinant proteins could specifically react with anti-Brucella bovine serum, and had no cross reaction with sera against other diseases. Later, we developed a fluorescent-labeled immunochromatographic strip for rapid detection of bovine brucellosis, on the basis of the selection of various solid materials and the optimization of reaction buffers and reaction conditions.The sensitivity assay indicated that the fluorescent-labeled immunechromatography strip could recognize the 1:100 dilution. It also distinguished bovine brucellosis from other diseases well, such as tuberculosis, bluetongue, viral diarrhea, FMDV, pasteurellosis and leukemia. At last, we tested 200 clinical bovine sera samples with the newly established method and commercial ELISA kit (IDEXX), and the concordance rate for the two different methods was 93.5%.Detection with the fluorescence labeled immunochromatographic strip has an advantages of good specificity, sensitivity, and repeatability, and it has great potential in preliminary detection of the antibody of bovine brucellosis serum quickly in practice.