Human iPS （induced pluripotent stem） cell line was derived from human foreskin fibroblasts （HFFs） by retroviral expression of OCT4, SOX2, KLF4, and c-MYCgenes. The cells were derived using morphological selection criteria and without the use of fluorescent marker or drug selection. When cultured under standard humanES cell culture conditions, the morphology of human iPS cells is identical to that of human ES cells. The cells also express the pluripotency markers SSEA-3 andNanog, and demonstrate strong endogenous alkaline phosphatase activity. The low passage iPS cells are highly viable and have been pre-adapted to serum-free,feeder-free culture conditions.
