Human umbilical cord conditioned medium: a stimulus for human CFU-G.

Segments of human umbilical cord have been used to prepare a highly active conditioned medium (HUCCM) for in vitro human granulopoiesis and have been compared with human placenta conditioned medium (HPCM) and feeder layers. The HUCCM produced more colonies on day 7 than HPCM (P less than 0.001), and colonies consisted almost exclusively (over 98%) of granulocytic cells by both morphological and cytochemical analysis. The HUCCM-stimulated colonies have a short culture life, the number of colonies being maximal on day 7 of culture with few colonies remaining on day 10. The main source of the colony-stimulating activity in the umbilical cord was found in the Wharton's Jelly component.