Expression of surface molecules by vesicles derived from cultured GC B cells. GC B cells were stained with PKH26-GL and FITC-conjugated MoAb against several surface molecules present on GC B cells and against an irrelevant antigen (control). After 2 hours, cell-free SN was obtained and analyzed by flow cytometry. (A) Contour plots of FL2 (PKH26-GL staining) versus FL1 (indicated molecule) from one representative example are shown. (B) Values were expressed as the percentage of particles positive for each molecule. Results represent the mean ± SEM of three experiments.