Exosomes, your body’s answer to immune health

Mesenchymal stromal cells (MSC) have a profound effect on the regulation of the immune system. MSCs show low expression of major histocompatibility complex (MHC)-II and costimulatory surface molecules that include CD40, CD40L, CD80 and CD86, indicating immunomodulatory properties (1). Interestingly, prior research indicated that MSCs are important immune modulators that exert their biological effects in a paracrine manner, involving secretion of exosomes. Exosomes have emerged as an important means for cellular communication through the transfer of proteins and genetic material between cells. Exosomes are a form of extracellular lipid vesicle that are usually 40–100 nm in diameter, have a density of 1.10–1.18 g/mL on sucrose gradients and contain exosome membrane-specific proteins such as CD9, CD63 and CD81 (2).