Abstract: 【Objective】To isolate exosomes （Exos） secreted by RAW264.7 macrophages infected with Listeria monocytogenes （LM）, and to explore their regulatory effects and mechanisms on RAW264.7 macrophages and CD8⁺ T lymphocytes, which could provide theoretical reference for revealing the mechanisms of LM infection, intracellular survival and immune escape.【Method】The exosomes of RAW264.7 macrophages infected with LM （LM-Exos） were extracted by differential ultracentrifugation combined with molecular exclusion method, and the phenotype of LM-Exos was identified by transmission electron microscopy, particle size analyzer and Western blotting. The regulatory effects of different doses of LM-Exos on RAW264.7 macrophages and CD8⁺ T lymphocytes were analyzed by real-time fluorescence quantitative PCR, cell viability detection and ELISA. 【Result】LM-Exos had a double-layered membrane structure, a round-like vesicle with a diameter of approximately 60-80 nm. Western blotting results showed that the surface of LM-Exos contained CD9, CD63 and TSG101 specific marker proteins. The effect of LM-Exos on the morphology and function of RAW264.7 macrophages was obviously concentration-dependent. As the LM-Exos stimulation time increased, the cell morphology gradually differentiated from round to long spindle-shaped, and showed pseudopodia of different shapes. Real-time fluorescence quantitative PCR results showed that with the increase of LM-Exos stimulation concentration, the relative expression of IL-1β, IL-10, IL-6 and TNF-α genes showed increasing trend. Stimulated by high-concentration LM-Exos, the viability of RAW264.7 macrophages slightly decreased but their resistance to LM EGD-e increased. Compared with the low-concentration LM-Exos stimulation group, high-concentration LM-Exos stimulation significantly（P＜0.05） or extremely significantly （P＜0.01） increased the relative secretion levels of TNF-α and IL-10 in CD8⁺ T lymphocytes, and induced morphological changes in CD8⁺ T lymphocytes, and increased levels of apoptosis. 【Conclusion】Different doses of LM-Exos show different regulatory effects on RAW264.7 macrophages and CD8⁺ T lymphocytes. LM-Exos can enhance the resistance of RAW264.7 macrophages to LM EGD-e, and can also induce CD8⁺ T lymphocyte differentiation and apoptosis. LM-Exos can act as an immune activator to enhance the immune function of RAW264.7 macrophages. High doses of LM-Exos may weaken the body’s immune response by inducing T cell apoptosis, thereby achieving LM immune escape. This dual effect may be an important mechanism for LM to achieve immune escape during infection.