The effect of various treatments of human erythroblasts on the appearance of the conformational form of Bax associated with apoptosis.

Human erythroblasts on day 5 to 7 of culture were treated for 8 hours with medium containing either Epo 2 U/mL and SCF 20 ng/mL, no growth factors, no growth factors and LiCl (20 mM), or no growth factors and zVAD-FMK (100 μM). (A) Cells in cytospin preparations were immunostained with a conformation sensitive anti-Bax* antibody and the mean percentage ± SEM of positive cells after 8 hours is shown (n = 3). (B) Anti-Bax* immunostained cells were mounted in medium containing DAPI to visualize nuclear material. After 8 hours in growth factor–deprived conditions (NIL), apoptotic Bax*-positive cells with condensed nuclei are seen, indicated by A, as well as viable Bax*-negative cells with normal nuclear morphology, indicated by N, (× 100 oil objective). After 8 hours in the zVAD condition, although nuclear morphology remains normal in all cells, many are seen to be Bax* positive, indicated by B, (× 100 oil objective, zoom × 1.5).