Fig. 3

a Increased viability of serum-starved A4573 ES cells by repetitive stimulation with rhIL6 (d 0, 2, 4; 10 ng/ml). Fold-change (x) of MTT conversion rates (n = 5; mean ± SD) relative to rates of cells measured 24 h after seeding and set to 1 (100 %) are shown. Statistical significance of IL6 treatment relative to controls is indicated (Mann–Whitney-U-Test; * = p < 0.05). b Serial supply of rhIL6 reduces rate of apoptosis from serum starvation in A4573 ES cells. Serum-starved cells of ES cell line A4573 cells were stimulated repetitively with rhIL6 (10 ng/ml on indicated days) and harvested on day 5. Sub-G1 DNA content was used as a measure of apoptosis. Bars (n = 3; mean ± SD) indicate fraction of cells (%) containing a sub-G1 DNA content. Similar results could be shown in two other independent experiments