Flow cytometric analysis of cell surface expression of CD41a and CD42a on starting and migrated cell populations. After migration, cultured cells were labeled with an R-PE–conjugated anti-CD41a MoAb and a FITC-conjugated anti-CD42a MoAb. (A, B, C) An example of double-color fluorescence beween CD41a and CD42a (A) and the respective controls (B, C). The cells within the lymphoid blast window (R1, Fig 7) were analyzed for the expression of CD42a (D) and CD41a (E). The thick line shows the staining of cells that migrated in response to an optimal concentration of SDF-1 (500 ng/mL). Broken lines represent the staining of the starting cell population, and dotted lines represent the staining with control antibodies. In two experiments, CD42a (F) and CD41a (G) staining was compared between the cells that migrated in response to SDF-1 (thick line) and to control media (thin line). (H) Migration of CD41a^low/CD42a^low cells. The mean and SD percentages of CD42a^low/CD41a^low were determined by gating on the entire population of CD41a⁺cells.