Surface morphologies of white blood cells. SEMs of a human blood lymphocyte (A), mouse blood lymphocyte (B), 300.19 murine pre-B lymphoma cell (C), human blood monocyte (E), and human blood PMN (F). Scale bars represent 2 μm. (D) Histogram of microvillar lengths for 300.19 cells (▪), mouse blood lymphocytes (▧), and human blood lymphocytes (▦). Bins are 0.05 μm. Numeric data are in Table 1.