Expression of surface antigens on primitive HPCs.

Expression of surface antigens on primitive hematopoietic cells that were generated after 2 weeks' expansion of CB-derived CD34⁺ cells on hTERT-stromal (panel A) or primary stromal cells (panel B). The x-axis indicates CD34 expression labeled with FITC-conjugated monoclonal antibody. The y-axis indicates CD90, CD117, or AC133 expression labeled with PE-conjugated monoclonal antibody. Positivity for a surface antigen was defined by the use of the isotype control monoclonal antibody. Data shown are from 2 independent experiments, each done in quadruplicate.