Fig. 3

IVIG reduce proliferation rates and accelerate growth of cellular protrusions in differentiation competent Schwann cells. a–d Schwann cell proliferation is reduced after 2 days of stimulation with 20 mg/ml dialysed IVIG (gray bars) compared to control buffer (ctrl) preparations (black bars). a BrdU labeling was performed in the last 8 or 24 h (8h, 24h) of the IVIG treatment and evaluation of the percentage of BrdU/DAPI double positive (BrdU+) nuclei compared to total number of DAPI nuclei revealed a significant reduction of proliferating cells. b, c Representative photographs of DAPI (blue) and BrdU (green) labeled nuclei after 8 h BrdU pulse of control buffer b and IVIG c stimulated cells. d Staining against the proliferation markers Ki67 and determination of the percentage of Ki67/DAPI double positive (Ki67+) nuclei in relation to the total number of DAPI positive nuclei. e–g Quantification of the average Schwann cell protrusion lengths revealed significantly accelerated growth of cellular processes in early stages of the differentiation process. e The cell processes of p57kip2 suppressed cells (diff.) were found to be significantly longer after 3 days (3d) IVIG stimulation when compared to control buffer treated cells. However, no difference was observed in non-differentiating (non-diff.) cells. f, g Representative photographs of differentiating citrine positive Schwann cells after 3 days control buffer (f) or IVIG (g) treatment; cell processes are marked by white arrows. t test (ns, not significant, *p < 0.05, ***p < 0.001). Error bars represent SEM. Scale bars, 100 μm in b, c; 200 μm in g. n = 4 for a–c, n = 2 for d, n = 10 for e–g