Blocking of Ihh by 5E1 monoclonal Ab in coculture with control or Ihh stromal cells. Expanded hematopoietic cells were harvested at 2 weeks and analyzed. The x-axis indicates the concentration of blocking Ab 5E1, and the y-axis indicates the number of cells. Ai and Bi indicate the total number of CFU-Cs; Aii and Bii, the total number of CFU-Mix's. (A) Ex vivo expansion on control stromal cells. (B) Ex vivo expansion on Ihh stromal cells. *P < .05 versus vehicle (0 μg/mL Ab 5E1) (Student t test). Data represent 4 independent experiments, each done in quadruplicate. Results are expressed as means ± SD.