Quantification of secreted proteins.

<p>The level of secreted proteins in culture supernatant was measured by enzyme-linked immunosorbent assay. Proteins secreted at (A) 300–8000 pg/ml and (B) lower than 300 pg/ml are indicated. The control is a culture supernatant from CGS expanded cord blood CD34+ cells alone. Conditioned medium was harvested from a starting cell number of 2 x10⁶/ml HS5 and HS27a marrow fibroblast. Mean of three independent measurements are presented. ** less than the lowest detection limit of the assay.