Biological Activity of Human TPO Isoforms
| TPO Isoforms . | % of Culture Supernants Added . | ||||
|---|---|---|---|---|---|
| 50 . | 10 . | 2 . | 0.40 . | 0.08 . | |
| TPO-1 | 0.953 | 1.155 | 0.871 | 0.489 | 0.260 |
| TPO-5 | 0.243 | 0.292 | 0.248 | 0.250 | 0.248 |
| TPO-6 | 0.232 | 0.258 | 0.252 | 0.250 | 0.254 |
| Medium | 0.236 | ND | ND | ND | ND |
| TPO Isoforms . | % of Culture Supernants Added . | ||||
|---|---|---|---|---|---|
| 50 . | 10 . | 2 . | 0.40 . | 0.08 . | |
| TPO-1 | 0.953 | 1.155 | 0.871 | 0.489 | 0.260 |
| TPO-5 | 0.243 | 0.292 | 0.248 | 0.250 | 0.248 |
| TPO-6 | 0.232 | 0.258 | 0.252 | 0.250 | 0.254 |
| Medium | 0.236 | ND | ND | ND | ND |
Data are shown as the absorbance at 450 nm in a colorimetric assay. Culture supernatants from COS-1 cells that expressed each TPO isoform were added in duplicate to the culture of FDCP-hMp15 cells at varying concentrations and were tested for the ability to stimulate the cell growth as described in Materials and Methods.
Abbreviation: ND, not done.