Brucella outer membrane proteins to control maturation and antigen presentation of mouse dendritic cells

Brucellosis is a highly contagious zoonotic disease, which seriously endangers animal husbandry in China. Bone marrow-derived dendritic cells (DCs) are full-time antigen presenting cells (APC) that play an important role in the interaction between pathogens and host immunity. DCs were stimulated with Brucella major outer membrane proteins (OMPs: OMP10, OMP19, OMP25, BP26 and OMP31) and Brucella mutants (Δ omp10 , Δ omp19 , Δ omp25 , Δ bp26 , Δ omp31 ) to examine effects on DC maturity and antigen presentation. Brucella OMP10, OMP19 and BP26; Brucella mutants Δ omp10 , Δ omp19 , Δ omp25 , Δ bp26 , Δ omp31 and Brucella RB51 induced DC maturation and antigen presentation efficiency in mice, activated proliferation of T lymphocytes, and decreased apoptosis, which helped the host recognize antigens and eliminate pathogens. However, B. abortus 2308 evaded the host immune function and established chronic infection by maintaining a balance between intracellular replication and inducing apoptosis, thus reducing DC maturation and antigen presentation to T cells. Toll-like receptor (TLR) -mediated signaling pathways were involved in the DC maturation and antigen presentation induced by Brucella OMPs. These results enhance understanding of Brucella pathogenesis and the host protective immune response mechanism and lay the foundation for the rational design of Brucella vaccines.