Figure 5.

Wnt3A inhibits the initial phase of stromal supported cell division of BM B progenitors. Highly purified BM CD10⁺CFSE^mean cells were grown on a confluent layer of MS-5 and treated with Wnt3A (25–400 ng/ml) or medium only. After three days, the cells were analyzed on a FACScan flow cytometer for the number of cell divisions of CD19⁺ cells. A) Tracking histograms of cell divisions of CFSE-labeled BM B progenitor cells in the presence or absence of Wnt3A (100 ng/ml) One representative experiment of six is shown. B) Dose dependent inhibition of cell division of CD34⁺ pro-B cells and CD34^- pre-B cells by Wnt3A (closed circles). The inhibitory effect of Wnt3A was blocked by Wnt antagonist sFRP1 (2 μg/ml) (open circle). Data are shown as percentage of cells that had gone through one or more cell divisions, as determined by cell division tracking with CFSE. One representative experiment of two is shown, except for Wnt3A (100 ng/ml) and Wnt3A + FRP1 (2 μg/ml) where one representative experiment of six is shown (*p < 0.05, Wilcoxon Signed Ranks Test, n = 6).