Loss of sensitivity to TRAIL of erythroid cells at late stages of differentiation.

(A) 14-day viable erythroid cells were detected by either FSC/SSC or PI staining analyses. Representative FSC/SSC (left and right panels) and PI (central panel) staining analyses are shown only for control cultures, since similar profiles were obtained in TRAIL- and anti-CD95-treated cells. The same cluster of dead cells was clearly detectable by both FSC/SSC and PI staining analyses. Viable cells, gated in R1 (region 1), were examined for glycophorin A expression, as shown in (B). (B) Cultures were supplemented with irrelevant IgM mAb and rHis6-tag peptide (CONT), TRAIL, or anti-CD95 (CH 11) IgM mAb for the last 20 hours before glycophorin A staining. X-axis: glycophorin A relative expression. Y-axis: relative cell number. Percentages of glycophorin A⁺ cells are indicated.