Induced pluripotent stem cells (iPSC) were obtained from frozen or fresh PBMC [19] using the integration-free CytoTune-iPS Sendai Reprogramming Kit (Invitrogen, Carlsbad, CA). This protocol utilizes Sendai virus particles to transduce the four Yamanaka factors [20, 21]. Transduced cells were cultured in mouse embryonic fibroblasts feeder (MEF) cultures and fed with iPSC medium complemented with bFGF (Invitrogen, Carlsbad, CA) until small colonies appeared in about two weeks. The small colonies were maintained for two additional weeks before selection for expansion into individual iPSC lines [22].
