Fig 1: Cellular binding and internalization assay using mouse NPC. (a) Cellular dot plot after staining with CD146 and CD45. X axis (Pacific Blue) and Y axis (FITC) shows CD45 and CD146, respectively. CD146 high/CD45 low, CD146 low/CD45 low, and CD146 low/CD45 high population were named as P1, P2, and P3, respectively. (b) Histogram of the FcγRIIB expression in each population. X axis (APC) shows the fluorescence of Alexa Fluor 647. Red shows staining with anti- FcγRIIB antibody and blue shows unstaining. (c) Concentration-dependent binding of the antibody in P2. The antibody was incubated at 4 °C for 60 min, and fluorescence was detected by FCM. The data were fitted with the receptor-ligand binding equation. (d) Concentration-dependent internalization rate of the antibody in P2. The antibody was incubated at 37 °C for 5 min. The data were fitted with the Michaelis–Menten equation. Each point shows the mean ± SD (n = 3).