**9. Conclusions**

TEX are rapidly emerging as the major component of immunoinhibitory signaling that prevails in the TME. TEX present in body fluids a subset of circulating EVs. The large quantity and enormous diversity of circulating EVs in plasma of patients with cancer with respect to cellular origin, molecular characteristics, genetic content and functions imposes a need for the isolation of TEX and their separation from non-malignant vesicles. This approach allows for studies of impact TEX exert on cells in the TME and of TEX value as potential cancer biomarkers. To dissect the EV diversity in body fluids, strategies are necessary for their capture, isolation from body fluids and separation of various EV subsets without interference with EV molecular identities and functions. Among various isolation strategies, immune capture with Abs specific for proteins carried on the EV surface has been most frequently utilized with a variable level of success. While in principle, immune capture is the rational strategy for EV pulldown from plasma, its application to nanovesicles requires an understanding of EV characteristics and EV biology. As the latter is still largely lacking, all EV immune capture strategies may backfire, for reasons that may not be anticipated, such as high levels of a soluble target Ag in plasma or the presence on vesicles of a "corona" of contaminating plasma proteins. The set of stringent requirements for vesicle immune capture from plasma that we have discussed allows
