Phenotypic differences between FL and FBM CD34⁺ cells.

Selected FL and FBM cells were analyzed for the expression of CD34 (x-axis) and CD38 (y-axis), as shown in panels A and B, respectively. A larger group of CD34⁺CD38⁻cells was detected among FL than among FBM CD34⁺ cells. In addition, cells expressing higher levels of CD38 (CD38⁺⁺) were more prominent among FBM cells. Most FL CD34⁺CD38⁺ cells coexpressed CD33⁺, whereas most of the corresponding FBM cells were CD19⁺(data not shown). Panels C and D depict Hst (x-axis) and PY (y-axis) staining of FL and FBM CD34⁺ cells, respectively. Percentages of cells in the different phases of the cell cycle (given as percentages in each quadrant under panels C and D) were similar for FL and FBM. The horizontal cursor separating G₀ from G₁ cells was positioned to separate PY staining into the lower one fourth containing G₀ cells and the upper three fourths containing G₁ cells. Data shown in panels A through D were derived from the analysis of FL and FBM cells from one fetus. FL (E-G) and FBM (H-J). CD34⁺ cells were sorted into G₀, G₁, and S/G₂+M cells based on their Hst and PY staining pattern. Sorted cells were stained with propidium iodide and were analyzed on a FACScan for their cell cycle status, shown for G₀ cells in panels E and H, for G₁ cells in panels F and I, and for S/G₂+M cells in panels G and J. Numbers inside panels E through J represent the percentages of cells detected in S/G₂+M in each sorted group based on the positions of the gates to the right in each panel. Gates shown to the left in panels E through J denote the position of cells in G₀/G₁.