CD34+ Selection: The Basic Component for Graft Engineering.

The hematopoietic system consists of a network of stem and progenitor cells of varying degrees of maturity interacting with other cells that act in supportive and regulatory capacities. Many cell types have been identified by their in vivo or ex vivo growth potential, i.e., colony assays, or by physical characteristics like cell-surface markers which can be identified by monoclonal antibodies. One of the most studied antibody markers is the CD34 antigen which is present on the most primitive hematopoietic progenitor cells.