Figure 3.

Brucella can inhibit the secretion of IL-2 by antigen presenting cells, and then prevent natural killer cells (NK) from secreting inflammatory factors such as IFN-γ and TNF-α. Brucella can also inhibit IFN-γ mediated phagocytosis to escape the killing of immune system. Brucella affects the maturation of DC by blocking TLR2 receptor pathway, and interferes with the establishment of Th1 immune response by inhibiting macrophages to reduce IL-12 secretion and preventing DC from activating T-lymphocytes.