Development of a Chemiluminescence Immunoassay for the Serological Diagnosis of Sheep and Bovine Brucellosis

Brucellosis, a zoonotic infection caused by the intracellular pathogen <i>Brucella</i>, leads to chronic multi-organ damage. Currently, rapid, accurate, and sensitive diagnostic technologies are crucial for the prevention and control of brucellosis. This study describes the development of a chemiluminescent immunoassay (Bru-CLIA) for sheep and bovine brucellosis antibody detection, utilizing <i>Brucella abortus</i> strain A19 lipopolysaccharide-coated magnetic particles (LPS-MPs) as the serum antigen and acridinium ester-labeled recombinant streptococcal protein G (AE-SPG) for signal generation. After optimizing the assay's parameters, the Bru-CLIA demonstrated a sensitivity of approximately 1 IU/mL and 2 IU/mL for detecting sheep and bovine brucellosis, respectively. No cross-reactivity was observed with sera from animals immunized with <i>Escherichia coli O157:H7</i>, <i>Mycobacterium tuberculosis</i>, <i>Vibrio cholerae</i>, <i>Legionella</i>, <i>Salmonella</i>, <i>Foot and Mouth Disease virus types O and A</i>, <i>Bovine viral diarrhea virus</i>, <i>Sheep contagious pleuropneumonia</i>, <i>Goat pox virus</i>, or <i>Peste des Petits Ruminants virus</i>, indicating strong specificity. The testing of 81 sheep serum samples and 96 bovine serum samples revealed that Bru-CLIA showed 87.65% and 93.75% concordance with the ID-VET commercial kits for sheep and bovine brucellosis detection, respectively. These results demonstrate that Bru-CLIA offers high specificity, sensitivity, repeatability, and reliability, making it a viable rapid diagnostic tool for the epidemiological surveillance of brucellosis.