Fig. 1. Characterization of purified OPCs. Cells were purified by Percoll gradient centrifugation and cultured in the presence of PDGF (5 ng/ml) and NT3 (10 ng/ml) for 5 days. Immunofluorescence staining shows that most cells exhibit A2B5 (A) and PSA (C) immunoreactivity. (B,D) Phase contrast photographs corresponding to A and C, respectively. Bar, 40 µm.