Western blot: H4 human neuroglioma cell line coexpressing human alphasyn tagged with either the amino-terminal (SL1) or the carboxyterminal fragments (SL2) of Gaussia princeps luciferase (SL1SL2 cells) were treated with tetracycline to block the expression of SL1 and SL2 and SL1SL2 exosomes were resolved by electrophoresis, transferred to PVDF membrane, and stained with anti-CD9 followed by ARG23710 Goat anti-Mouse IgA + IgG + IgM antibody (HRP) (pre-adsorbed) and chemiluminescent detection.