Banking Human Pluripotent Stem Cell Lines for Clinical Application?

Abstract

In this month’s issue of the Journal, Tamaoki et al. report the derivation of human pluripotent stem cell lines from dental pulp cells, which can be obtained from extracted teeth. The authors present an interesting possibility for constructing HLAtype banking of human induced pluripotent stem cell (hiPSC) lines from such easily accessible sources. More specifically, they report the presence of 2 donated samples that were homozygous for 3 HLA-loci (HLA-A, B, DR), which are considered to be most valuable for predicting the intensity of immunological rejection after transplantation therapy. The possibility of the HLA-type banking of human embryonic stem cell (hESC) lines was first reported by Taylor et al. (2005), with calculations based on HLA-type distribution in a UK population. Our group later published the supportive potential of banking conventional or parthenogenetic hESC lines (Nakajima et al., 2007), with projections for the Japanese population. After derivation of hiPSC lines was reported (Takahashi et al., 2007), we extended these findings to the banking possibility of hiPSC lines derived from somatic cells donated by individuals homozygous for the 3 HLA loci (Nakatsuji et al., 2008). This extrapolation predicts that banking of ca. 200 hESC lines would provide beneficial matching for 80% of the Japanese population, because one can find the cell line with 2 loci matched (at low-resolution matching level) among the 3 most important HLA-loci. Furthermore, if one could accumulate hESC or hiPSC lines homozygous for the 3 HLA-loci, 50 lines would enable full matching for 80-90% of the population, because homozygous cell lines can give much wider HLA-type matching than heterozygous ones. This new report by Tamaoki et al. (2010) indicates that it is indeed possible to identify homozygous donors for hiPSC lines for the construction of such HLA-type banking. Furthermore, a report was recently published for a Chinese population (Lin et al., 2009), in which ca. 200 hESC lines were derived from donated spare embryos, and analysis of HLA-typing data predicted beneficial matching for the majority of the local population, as projected by these assumptions. Another possibility of deriving parthenogenetic ESC lines was Banking Human Pluripotent Stem Cell Lines for Clinical Application?