Clean-Up Human Embryonic Stem Cell Lines Using Humanized Culture Condition.

Human embryonic stem cell (hESC) culture system has been changing culture conditions from conventional to xeno-free for therapeutic cell applications, and -glycolylneuraminic acid (Neu5Gc) could be a useful indicator of xenogeneic contaminations in hESCs because human cells can no longer produce it genetically. We set up the humanized culture condition using commercially available humanized materials and two different adaptation methods: sequential or direct. SNUhES4 and H1 hESC lines, previously established in conventional culture conditions, were maintained using the humanized culture condition and were examined for the presence of Neu5Gc. The hESCs showed the same morphology and character as those of the conventional culture condition. Moreover, they were negative for Neu5Gc within two passages without loss of pluripotency. This study suggested that this method can effectively cleanse previously established hESC lines, bringing them one step closer to being clinical-grade hESCs.