Murine long-term repopulating ability is compromised by ex vivo culture in serum-free medium despite preservation of committed progenitors

Hematopoietic progenitor cells can be maintained and expanded ex vivo in standard or serum-free culture medium supplemented with a variety of stimulatory cytokines, The use of serum-free medium allows specification of reproducible and precise growth conditions optimal for various applications and is more acceptable from a safety and regulatory point of view, Human and murine committed progenitor cells have been shown to be equivalently or better supported by serum-free culture conditions in the presence of multicytokine combinations, but there is little information on the effects of such culture conditions on repopulating stem cells, We used a murine competitive repopulation model to assess the effect of serum-free versus serum-containing ex vivo culture on long-term reconstituting cells, Despite equivalent numbers of committed CFU-C and day 12 CFU-S present after 4 days of culture of murine marrow in serum-free or serum-containing conditions in the presence of IL-3, IL-6, and SCF, long-term reconstituting activity was significantly impaired by serum-free culture, These findings may have important implications for transplantation and gene therapy applications.