Rabbit anti cd81

Liquid-phase EV and MBV, derived from three separate cultures of 3T3 fibroblasts, were respectively pooled and quantified by nanotracking particle analysis. For both immunoblot and silverstain analysis, an equal number of vesicles for both the liquid-phase EV and MBV samples were loaded onto the gel. MBV or liquid-phase EV (21 × 10¹¹) was mixed with 2× Laemmli buffer (R&D Systems) containing 5% β mercaptoethanol (Sigma-Aldrich), resolved on a 4 to 20% gradient SDS–polyacrylamide gel electrophoresis (Bio-Rad), and then transferred onto a polyvinylidene difluoride membrane. Membranes were incubated overnight with the following primary antibodies: rabbit anti-CD63, rabbit anti-CD81, rabbit anti-CD9, and rabbit anti-Hsp70, at 1:1000 dilution (System Biosciences). Membranes were washed three times for 15 min each before and after they were incubated with goat anti-rabbit secondary antibody, at 1:5000 dilution (System Biosciences). The washed membranes were exposed to chemiluminescent substrate (Bio-Rad) and then visualized using a ChemiDoc Touch instrument (Bio-Rad). Silver staining of gels was performed using the Silver Stain Plus Kit (Bio-Rad) according to the manufacturer’s instruction and visualized using a ChemiDoc Touch instrument (Bio-Rad).