Brucellosis, a major global zoonosis causing over 2.1 million human infections annually, poses a significant threat to public health and livestock economies. Conventional vaccines face substantial limitations, including residual virulence and diagnostic interference in live attenuated vaccines, and poor immunogenicity in subunit vaccines. To address these issues, we developed BP26-OMP16Es, a self-assembling nanoparticle vaccine constructed by fusing immunodominant B- and T-cell epitopes from OMP16 to the self-assembling antigen BP26 via flexible linkers, yielding single-copy (1×) and double-copy (2×) epitope tandem nanoparticles. These particles formed homogeneous, barrel-shaped structures (14–23 nm) with strong immunoreactivity against Brucella-specific antibodies. In murine models, the vaccine elicited potent humoral and cellular immune responses, characterized by high antibody titers, enhanced IFN-γ+ CD8+ T cell proliferation, a balanced Th1/Th2 profile, and the induction of immunological memory for durable protection. Immune sera also mediated effective clearance of infected macrophages via antibody-dependent cellular cytotoxicity (ADCC). Challenge experiments confirmed that the vaccine significantly reduced splenic Brucella burden and alleviated pathological damage, with the 2× construct offering superior protection. In summary, this study integrates self-assembling nanotechnology with a multiepitope strategy to create a safe and potent vaccine platform. The 2× design enhances epitope density, boosting immunogenicity and conferring solid protection against Brucella infection. This approach provides valuable insights for developing vaccines against brucellosis and other intracellular pathogens.
Yun-Yi Zhai, Kai-Hui Sun, G. WuDong et al.· ACS Nano· 0 citations
BACKGROUND
Brucellosis, a severe zoonotic infectious disease, poses substantial economic and health threats globally. The intracellular survival strategy of Brucella complicates disease control, highlighting the need for novel immunotherapeutic strategies such as antibody-based therapies and multi-epitope vaccines.
RESULTS
This study generated two IgM monoclonal antibodies (D3 and F5) against the conserved outer membrane protein OMP16 of Brucella using hybridoma technology. Peptide scanning and Western blot identified their linear epitopes (D3: 77TLSKQAQW84; F5: 120RDFLASRG127), which are highly conserved among major Brucella species. Integrated approaches-including molecular docking, alanine-scanning mutagenesis, and dot-blot assays-revealed key residues at the epitope interface that form stable bonds with antibody complementarity-determining regions (CDRs). Functionally, both antibodies activated the complement system, with F5 exhibiting significant complement-dependent bacteriolytic activity in vitro. Furthermore, in the presence of complement, D3 and F5 enhanced macrophage-mediated opsonophagocytosis and intracellular killing of Brucella abortus A19. In a mouse infection model, passive immunization with either antibody significantly alleviated infection-induced weight loss and splenomegaly and reduced bacterial load in the spleen.
CONCLUSIONS
Our study underscores the role of IgM antibodies in combating Brucella infection, offers insights for antibody-based immunotherapy, and provides a theoretical foundation for developing multi-epitope vaccines based on the conserved epitopes and critical residues.
Yunyi Zhai, Kaihui Sun, Ye Yuan et al.· BMC Biology· 0 citations
We use cookies to run the site and, with your consent, for analytics and to show ads.
See our Cookie Policy.
