FIGURE 2.

Flow cytometric analysis based on cell size, granularity and viability identified microglia with CD11b^high/CD45^pos expression. (A) Microglia appeared homogeneous in cell size and granularity (R1). (B) Sytox green staining, a DNA-binding dye that is actively taken up by dying cells, distinguished the living cells (R2) from dead cells and debris. (C) Combined selection based on cell size, granularity, and viability (R1 and R2) resulted in a microglial purity of 92.4 ± 0.87% (mean ± SD), as identified by their characteristic CD11b^high/CD45^pos expression. A small fraction of lymphocytes was present to within the viable cells. To obtain a 100% pure microglial population, microglia (R3) were sorted.