Therefore, ex vivo expansion of BMSCs is required to obtain a sufficient number of transplantable cells. Since BMSCs require several kinds of supportive factors for their growth, it is standard practice to use fetal bovine serum (FBS), while autologous human serum (HS) and pooled allogeneic HS have also been used. It has been suggested that FBS may not be favorable for clinical applications due to the possible risk of contamination (prions, viruses, zoonosis) or immunological reactions against xenogeneic serum antigens (Agata et al., 2009). Although serious secondary effects of transplanted cells that were cultured in the presence of FBS have not been reported to date, a previous.
