TABLE 1.

Types of extracellular vesicles based on their size and biogenesis pathways.

Characteristic	Exosomes	Microvesicles	Apoptotic bodies
Size	40–120 nm	100–1000 nm	50–5000 nm
Morphology	Cup-shaped	Heterogeneous	Heterogeneous
Formation mechanism	Multivesicular body	Plasma membrane	Plasma membrane
Pathways	(1) ESCRT-dependent (2) Tetraspanin-dependent (3) Ceramide-dependent	(1) Ca+2-dependent (2) Stimuli-dependent	Apoptosis-related pathways
Content	Proteins, lipids, and nucleic acids	Proteins, lipids, and nucleic acids	Nuclear fractions, cell organelles
Markers	Alix, Tsg101, tetraspanins (CD81, CD63, CD9), flotillin, heat shock proteins. High acetylcholinesterase activity	Integrins, selectins, CD40	Annexin V, phosphatidylserine
	Definitive markers for the different EV subpopulations do not exist.

CD, cluster of differentiation; ESCRT, endosomal sorting complexes required for transport; EV, extracellular vesicle; TSG101, tumor susceptibility gene 101.