Immune capture and protein profiling of small extracellular vesicles from human plasma

Extracellular vesicles (EVs), the key players in inter-cellular communication, are produced by all cell types and are present in all body fluids. Analysis of the proteome content is an important approach in structural and functional studies of these vesicles. EVs circulating in human plasma are heterogeneous in size, cellular origin, and functions. This heterogeneity and the potential presence of contamination with plasma components such as lipoprotein particles and soluble plasma proteins represent a challenge in profiling the proteome of EV subsets by mass spectrometry. An immunocapture strategy prior to mass spectrometry may be used to isolate a homogeneous subpopulation of small EVs (sEV) with a specific endocytic origin from plasma or other biofluids. Immunocapture selectively separates EV subpopulations in biofluids based on the presence of a unique protein carried on the vesicle surface. The advantages and disadvantages of EV immune capture as a preparative step for mass spectrometry are discussed.

Automated summary

Extracellular vesicles (EVs) play a key role in intercellular communication and their proteome content is important for studying their structure and function. However, EVs circulating in the human plasma are heterogeneous and can be contaminated with plasma components, making it challenging to profile their proteome using mass spectrometry. An immunocapture strategy can be used to isolate homogeneous subpopulations of small EVs (sEV) with a specific endocytic origin, overcoming this challenge.