Regulation of Macrophage Polarization Mediated by Extracellular Vesicle During Bacterial Infection

Extracellular vesicles (EVs) are nanovesicles secreted by cells with lipid bilayer structure, which play a key role in the communication between bacteria and host cells. This paper reviews the role of EVs, particularly bacterial‐derived EVs (bEVs) and host cell (e.g., macrophage)‐derived exosomes, in the regulation of macrophage polarization during bacterial infection. Macrophages can differentiate into M1 and M2 types with different functions, which is very important in the innate immune response. bEVs and exosomes influence the polarization state of macrophages by carrying a variety of bioactive molecules, such as bacterial effectors, nucleic acids, and lipids, and finally, they are involved in the regulation of host immune and inflammatory responses. In addition, EVs show great potential in early disease diagnosis, vaccine development, and targeted therapy. However, the application of EVs still faces many challenges, including the development of isolation and purification techniques, the establishment of standardized processes, and the clarity of specific mechanisms. In this review, the mechanism of bEVs and exosomes in regulating macrophage polarization is systematically summarized, their potential applications in infectious diseases are explored, and directions for future research are proposed. With a deeper understanding of the function and regulatory mechanisms, EVs are expected to become a new diagnostic marker and a therapeutic tool, providing new strategies for the prevention and treatment of infectious diseases.