Establishment of a simple and novel method for contact-dependent intercellular interaction analysis using...

Extracellular vesicles (EVs), including exosomes, microvesicles, and apoptotic bodies, are membrane-bound vesicles secreted by cells. They play essential roles in intercellular communications and are involved in numerous physiological processes. Given their functional importance, EVs have emerged as promising tools for diagnosing and treating various diseases. In this study, we focused on the utility of EVs and explored their application in the analysis of contact-dependent cell-cell interactions, which are essential for the control of cell differentiation and induction of immune responses. Although several methods have been developed to evaluate these interactions, they often require complex procedures and advanced optimization, limiting their broad applicability. To overcome these limitations, we developed a novel method utilizing EVs to present membrane proteins in their native conformations. Our strategy involved producing fluorescently labeled EVs with target antigens and quantitatively assessing their binding to target cells via flow cytometry. Using fluorescently labeled EVs presenting with either an N-terminal pro-brain natriuretic peptide or interleukin-2 receptor, we successfully detected specific interactions with corresponding hybridoma B cell receptors. This simpler method requires no advanced optimization and effectively analyzes cell-cell interactions under physiological conditions in a high-throughput and quantitative manner. Our findings highlight the potential of this EV-based system as a valuable tool for studying membrane protein-mediated cell-cell interactions in bioscience research.