Expansion of AGM- or FL-derived CD34⁺/c-Kit⁺ cells in the FL microenvironment.

CD34⁺/c-Kit⁺ cells were sorted from E11.5 AGM, E14.5 FL, or E18.5 FL and cultured in the E14.5 FL microenvironment. The number of GFP⁺ floating cells generated over the stromal layer was counted by FACS on day 10. Under these culture conditions, 40% to 80% of floating cells were GFP⁺. Results are shown as fold expansion relative to the number of input CD34⁺/c-Kit⁺ cells in each culture condition. (Lane a) Whole AGM cells from 3 embryos containing 1.8 × 10⁴ CD34⁺/c-Kit⁺ cells were cultured in the microenvironment created by the AGM cells. (Lanes b-d) Whole AGM cells (1 × 10⁵) containing 2 × 10³ CD34⁺/c-Kit⁺ cells were cocultured in the FL microenvironment in the presence of various factors, as indicated. (Lanes e-m) CD34⁺/c-Kit⁺cells (2 × 10³) from different sources were cultured in the FL microenvironment under various culture conditions. Data shown are the mean ± SD of at least triplicate experiments.