Fig. 4. Development of adherent hematopoietic cell clusters. (A,B) An adherent
hematopoietic cell cluster (A) and a cluster with a cobblestone appearance
that grew underneath the OP9 stromal cells (B). (C) Alkaline phosphatase
staining of adherent hematopoietic cell clusters immunolabeled with human CD34
antibody. Scale bars: 100 µm.