[Investigation of exosomes secreted by different normal and malignant cells in vitro and in vivo].

Laser correlation spectroscopy, atomic force microscopy, and immunoaffinity chromatography were used to characterize exosomes produced by different human cells. The exosomes secreted into a culture medium by normal fibroblasts, dendritic cells, lymphocytes, as well as malignant cells obtained from tumors of various tissue origins. The similar investigations were made for exosomes detectable in plasma and cerebrospinal fluid. The dynamic light scattering technique has demonstrated that the exosomes from different sources are homogenous and similar in size of the order of 20 and 90 nm. The exceptional homogeneity of exosomes was confirmed by atomic force microscopy. The immunoaffinity method has shown that all the exosomes under study carry antigenic determinants recognizable by antibodies to the major histocompatibility complex of type 1 (HLA-ABC). A method is proposed for evidence-based detection of exosomes in various biological fluids. For this, dynamic light scattering detects 20- and 90-nm particles and whether they can be removed by immunoaffinity chromatography with HLA-ABC antibodies is checked.