Figure 2.

Separation of human lung macrophages by continuous density gradient. Cells (10⁷) were layered on continuous Percoll gradient prepared as described in Materials and Methods and centrifuged (1000 g, 22 °C, 20 min). Density marker beads were layered and centrifuged in a separate tube. Fractions of 0.5 mL were collected and the cells in each fraction were counted. Data are the mean ± SEM of four experiments.