BRUCELLA SPP. ANTIGENS IMPACT IN THE PATHOGENESIS AND DIAGNOSIS OF HUMAN BRUCELLOSIS

Abstract

Introduction. Brucellosis remains one of the most widespread and underdiagnosed zoonotic infections, with over 500,000 new human cases annually and continued endemic circulation in livestock. Brucella melitensis, B. abortus, B. suis, and B. canis are the key pathogenic species causing chronic disease with nonspecific clinical symptoms. Brucella antigens are central to the pathogenesis and immune response, yet current diagnostic tests lack sufficient specificity, and no licensed human vaccine is available. This highlights the urgent need for more accurate antigen-based tools for both diagnosis and prevention. Aim. To review and evaluate the main Brucella antigens with proven or potential diagnostic and vaccine value, focusing on their structural features, immunogenicity, and applicability in translational research. Search strategy: A systematic review was conducted following PRISMA guidelines. Literature searches were performed in PubMed, Scopus, and Web of Science (2018–2025) using predefined keywords related to Brucella antigens, diagnostics, and vaccine development. After multi-stage screening of titles, abstracts, and full texts, 106 studies were included in the final analysis, as illustrated in the PRISMA flow diagram. Results. Outer membrane proteins (Omp16, Omp19, Omp25, Omp31), periplasmic proteins (BP26, Cu/Zn-SOD, L7/L12), heat shock proteins (Hsp60, Hsp70), and Type IV secretion system proteins (VirB) demonstrate distinct immunogenic profiles. Among them, L7/L12, Omp19, and SOD show the highest promise in terms of serological sensitivity and protective immune stimulation. A subset of these antigens is currently being explored as part of recombinant subunit vaccine formulations. Conclusion. Molecularly defined Brucella antigens offer tangible opportunities to improve human brucellosis diagnostics and support the rational development of safer, targeted vaccines. Their documented immunological relevance justifies further preclinical evaluation and standardization in applied immunodiagnostics.