Selective proliferation and expansion of B-cell precursors from the embryo cell lines in response to IL-7 signals.

Six embryo cell lines and 2 LFL-derived cell lines harboring different percentages of B cells were used in these studies. The findings shown were obtained at 72 hours after culturing the cell lines in new ST2-coated plates with fresh medium and rIL-7. (A,B) Relative and absolute number of IgM⁺ B cells in embryo (black bars) and LFL (dashed bars) cell lines growing in cultures supplemented with or without rIL-7 at 3 ng/mL. (C) Dose-dependent rIL-7 cell proliferation (mean ± SD of triplicate cultures in each point) and total recovered cells in 4 independent embryo-derived cell lines (circles, continuous lines) and in LFL cell lines (triangles, dotted lines). (D) Total number of CD19⁺IgM⁻ cells recovered from rIL-7–enriched (3 ng/mL)-cultures or from cultures without rIL-7 addition. The total number of CD19⁺IgM⁺ B cells and CD19⁺IgM⁻ cells in both embryo and LFL cell lines was calculated by multiplying the total cells recovered by the frequency of IgM⁺ and IgM⁻ cells obtained in the flow cytometry analysis.