Figure 3

B-cell progenitors modulate the behavior of OP9 stromal cells in vitro. Panel (A-B) display pictures of OP-9 cells grown in parallel cultures with either conditioned media (A) or in direct contact with pro-B cells (B) generated by in vitro differentiation of LSK cells. The pictures are taken from the same six well tissue culture plates with 200 times amplification and under the same light conditions (Leica DFC290). The black bar indicates 100 μM. Panel (C) shows a representative sorting experiment where trypsin/EDTA treated co-cultures of OP9S and pro-B cells are separated based on forward scatter and Strawberry expression. Panel (D) display a cluster analysis of RMA normalized gene expression patterns in OP9S cells incubated with either conditioned media or the pre-B cell line 230-238. The analysis displays genes with an expression level above 100 and with at least 5-fold difference in expression in the two experiments with P-value < 0.05. Red indicates high and blue low expression.