FIG. 11.

Cells harvested from an 8-mL bioreactor after 16 days in culture were analyzed using immunofluoroesence, scanning electron microscopy (SEM), and FACS. For immunofluorescence the following colors were used for staining: Phalloidin (green) for the presence of actin, CD235a (red) for the characteristic marker present on RBCs, and DAPI for the presence of a nucleus. We were able to capture a nucleus being expelled from a cell (white arrow). Interestingly, the SEM image below also shows a cell that is invaginating in preparation for ejection of the nucleus. FACS results indicate that these cells have lost the CD34⁺ marker, are in a proliferative stage of growth, and possess markers (CD235a and enucleation) characteristic of mature RBCs. The above image was adapted from Benjamin Cummings, an imprint of Addison Wesley Longman, Inc. Color images available online at www.liebertonline.com/tec