Responsiveness of thymic B cells to exogenous IL-7.

(A) Phenotype of cells harvested 7 days after seeding FTOC with 5 × 10⁴ CD45R⁺sIgM⁻ BM cells in the presence or absence of 50 U/mL of IL-7. (B) Cells harvested 7 days after seeding FTOC with CD45R⁺sIgM⁻ BM cells could establish long-term cultures when seeded on S17 BM stromal cells in the presence of IL-7. Original magnification, × 100. (C) Expression of CD127 and CD45R on CD3⁻CD4⁻CD8⁻ TN thymocytes harvested from the fresh thymus.