Figure 1.

Brucella interacts with lipid rafts on the surface of cell membrane to enter macrophages and form Brucella-containing vacuoles (BCV). The early BCV in macrophages is called eBCV, it acquires some host marker molecules. With the maturation of eBCV, eBCV loses the marker of early endosome, and obtains the marker molecules of late endosome and lysosome recognition, so as to promote the fusion of eBCV and lysosome. Part of the eBCV escaped lysosome degradation and reached the ER, and then fused with the ER by Sar1 and Rab2 to form rBCV. Brucella proliferated in rBCV. At the late stage of infection, the rBCV containing a large number of Brucella transformed into aBCV. The aBCV released pathogens through cleavage and noncleavage mechanisms, and the intracellular circulation of Brucella ended.