Cells expanded in the presence of CD40L.
(A) Cells expanded in the presence of CD40L essentially belong to the myeloid and megakaryocytic lineages. Human CD34+progenitors were cultured 12 days in contact cocultures with ECs with 10% supernatant of nontransfected COS cells (control) or with 10% supernatant of CD40L-CD8α–transfected COS cells (CD40L). Results are expressed as the mean ± SD, of 4 experiments. (B, C) Megakaryocyte progenitors in the CD40L coculture system. Human CD34+progenitors were cultured 12 days in contact cocultures with HUVECs with 10% supernatant of nontransfected COS cells (control) or with 10% supernatant of CD40L-CD8α–transfected COS cells (CD40L) and assayed for colony-forming cells and colony-forming unit–megakaryocytes on a collagen-based system, followed by colony staining with an anti-GP IIb mAb (EDU-3) as described in “Materials and methods”. Center panel (B), noncontact cocultures; bottom panel (C), contact cocultures. Results are expressed as the mean ± SD colony number (for 105 cells), for 3 experiments.
