iPSC could be classified into two classes: primed and naive. The naive cells represent traits of mouse embryonic stem cells (mESC) derived from inner cell mass (ICM) or blastocyst from preimplantation embryo, contrarily to primed iPSC that resemble cells derived from murine postimplantation epiblasts. Naive pluripotent stem cells possess no tendency towards any lineage and retain an active X chromosome in female-derived iPSC. These cells are easier to maintain and differentiate, due to no prior lineage-commitment bias.

Celther Polska is currently acting to establish naive iPS cell lines for convenience of culture and broad spectrum of applications.