Table 1.

Immunosuppressive role of tumor cell-derived exosomes.

Target Cells	Functional Molecules	Effects	References
T cells	Galectin-9	Apoptosis of EBV-specific CD4 T cells and inhibition on Th1 cell function	[14]
	FasL	Apoptosis of T cells	[15]
	PD-L1	Inhibited proliferation and functions of T cells	[16]
	ULBP/MICA	Inhibition on the NKG2D signaling pathway	[17]
	TGF-β	Downregulation of NKG2D on CD8 T cells	[18]
	MiRNAs	Inhibition on the differentiation of Th cells	[19]
Tregs	TGF-β	Upregulation of Treg-related genes	[20]
	IL-10/IL-2	Increased amount and enhanced function of Tregs	[21]
Bregs	——	Differentiation into TGF-β-producing Bregs	[22]
	HMGB1	Increased TIM-1 Breg cells	[23]
Macrophages	miRNAs	Promotion on the IL-6 secretion of immune cells	[24]
	CSPG4, EGFR, and integrins	Increased M2 macrophages	[25]
	——	Increased proinflammatory factors	[26]
	Wnt5a	Improvement on the invasion ability of tumor	[27,28]
DCs	IL-6, HSP70, and HSP72	Activation of STAT3	[29,30,31]
	HLA-G	Suppression on T cells, NK cells, and DCs	[32]
	Galectin-9	Inhibition on the maturation and failure of activating cytotoxic T cells	[33]
	miRNAs	Inhibited RFXAP and toll-like receptor 4 (TLR4) expression in DCs	[34]
	S100A9	Decreased costimulatory molecules on DCs	[35]
	HSP72 and HSP105	Increased secretion of IL-6 of DCs	[36]
NK cells	TGF-β	Downregulation of NKG2D and reduced cytolytic activity of NK cells	[37]
MDSCs	miRNAs	Activation of STAT1 and STAT3 pathways and expansion of MDSCs	[38,39]
	——	Release of NO from MDSCs	[15]
	HSP72/TLR2	Autocrine production of IL-6	[30]
	PGE2 and TGF-β	Differentiation of MDSCs from myeloid cells	[40]