Microscopy analysis of released vesicles (A) and their cellular generation (B). (A) Cell-free SN obtained from GC B cells cultured for 2 hours was passed through a filter (0.1-μm pore), and the filter was processed for scanning (A.1) and transmission (A.2) EM. Filter pores are seen as black holes in A.1. (B) GC B cells were stained with PKH26-GL and, after 2 hours, were analyzed under fluorescence microscopy (B.1). GC B cells cultured for 2 hours were studied by transmission EM (B.2) and scanning EM (B.3).