Table 1. The similarities and differences between MVs and OMVs.

	Membrane vesicles (MVs)	Outer membrane vesicles (OMVs)
Origin	Cytoplasmic membrane of Gram positive bacteria	Outer membrane of Gram negative bacteria
Size	∼20–150 nm in diameter	∼10–300 nm in diameter
Components	• Various fatty acids and phospholipids; • Cytoplasmic proteins; • Membrane-associated virulence proteins/enzymes; • lipoteichoic acid (LTA); • Peptidoglycan • DNAs • sRNAs	• Outer membrane proteins; • Periplasmic proteins and virulence factors; • Less cytoplasmic and inner-membrane proteins; • LPSs and phospholipids; • Peptidoglycan • DNAs • sRNAs