Selection of Brucella abortus mimetic epitopes for fast diagnostic purposes in cattle.

Bovine brucellosis is a disease that significantly impacts animal production and human health. Although many sensitive diagnostic tests are used, there is still no ideal fast serological test for all epidemiological situations. In this context, we developed peptides that mimic regions of antigenic proteins of Brucella abortus and can be used in serological diagnosis. RESULTS: From phage display technology, we randomly selected nine clones of phage displaying peptide binders to B. abortus. These clones were sequenced and translated. After molecular docking analysis, two peptides (Ba4 and Ba9) were selected, chemically synthesized, and verified for their potential diagnostic value. By enzyme-linked immunoassay (ELISA), Ba9 showed a sensitivity of up to 97.5% to detect antibodies circulating in animals with brucellosis. We incorporated the peptide Ba9 onto a bioelectrode (graphite modified with poly-3-hydroxyphenylacetic acid). Then, direct serum detection was demonstrated by differential pulse voltammetry, micrographs, and topographic analyses in addition to the average roughness coefficient (Ra) and the value of the mean squared deviation of the roughness (Rms). CONCLUSION: This work shows that the mimetic epitope of B. abortus can be useful for developing new platforms for diagnosing brucellosis. In addition, we propose a fast test based on an electrochemical sensor using graphite modified with poly-3-hydroxyphenylacetic acid.