Table 1 The role of different sEVs in the tumor microenvironment with corresponding immune cell populations

High expression of miR—203

Dendritic cells

Down-regulation of TLR4 and downstream cytokines, thereby inhibiting the immune response

[57]

High expression of miR-212-3p

Dendritic cells

Inhibit the expression of regulatory factor X-associated protein (RFXAP), reduce the expression of MHC II, and produce immune tolerance

[58]

High expression of CD63

T lymphocyte

Activate p38 mitogen-activated protein kinase (MAPK), induce cell apoptosis, and eventually lead to immunosuppression

[56]

High expression of tumor-associated antigens (TAAs)

B cell

As a bait for complement, it produces cytotoxicity and inhibits specific immune response

[60]

High expression of macrophage migration inhibitory factor (MIF)

Bone marrow-derived macrophages

Immunosuppressive cells are recruited to form an immunosuppressive environment

[40]

High expression of miR153

NK cells

Natural killer group 2 member D (NKG2D) was reduced by upregulation of hypoxia inducible factor 1-α (Hi1FA), and NK cells cleavage

[79]

High expression of miR-338-3p

Neutrophils

At present, the mechanism of action is not clear, biochemistry analysis indicated that it can inhibit the function of immune cells

[80]

High expression of miR-199b-5p

Neutrophils

At present, the mechanism of action is not clear, biochemistry analysis indicated that it can inhibit the function of immune cells

[80]

Lower expression of miR-340

Macrophages

At present, the mechanism of action is not clear, inhibits macrophages from becoming M1-like phenotype polarization in the peripheral and tumor immune microenvironment, and reduces T cells, especially CD8 + T cells

[81]

Lower expression of miR-128

All kinds of immune cells

At present, the mechanism of action is not clear, biochemistry analysis indicated that it can inhibit the function of immune cells

[64]