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The KCL031 human embryonic stem cell line was derived from a normal healthy blastocyst donated for research. The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment and under current Good Manufacturing Practice (cGMP) standards. Pluripotent state and differentiation potential were confirmed by in vitro and in vivo assays.
We generated KCL031 clinical grade hESC line following protocols, established previously (Ilic, D., et al., 2012, Stephenson, E., et al., 2012), and now adapted to cGMP conditions. The expression of the pluripotency markers was tested after freeze/thaw cycle (Fig. 1). Differentiation potential into three germ layers was verified in vitro (Fig. 2) and in vivo (Fig. 3), as well as targeted differentiation into cardiac myocytes (Fig. 4).
Molecular karyotyping using array comparative genomic hybridization aCGH identified deletion at 7q22.3 (105,465,968–105,516,305). Whole-genome single nucleotide polymorphism (SNP) array analysis detected loss at 8q24.23 (136,718,037–136,837,768) (Canham et al., 2015). The gain contains no genes and it has been also reported previously to occur in healthy individuals from worldwide population (Macdonald et al., 2014). Estimated frequency in the human population is 3.85% (Canham et al., 2015).
Donors were tested negative for Human Immunodeficiency Virus 1 (HIV1), Hepatitis B (HepB, HCB) and C Virus (HepC, HCV). We did not retest the line.
We also generated research grade of KCL031 line that is adapted to feeder-free conditions.
We distribute Patient Information Sheet (PIS) and consent form to the in vitro fertilization (IVF) patients if they opted to donate to research embryos that were stored for 5 or 10 years. They mail signed consent back to us and that might be months after the PIS and consent were mailed to them. If in meantime new versions of PIS/consent are implemented, we do not send these to the patients or ask them to re-sign; the whole process is done with the version that was given them initially. The PIS/consent documents (FRO-V.5) were created on Aug. 10, 2007. HFEA Code of Practice that was in effect at the time of document creation: Edition 7 — R.1 (http://www.hfea.gov.uk/2999.html). The donor couple signed the consent on Nov. 26, 2008. HFEA Code of Practice that was in effect at the time of donor signature: Edition 7 — R.4. HFEA Code of Practice Edition 7 — R.1 was in effect until Dec. 09, 2007, whereas 7 — R.4 was in effect: Oct. 02, 2008–Sep. 30, 2009.
Embryo culture and laser-assisted dissection of inner cell mass (ICM) were carried out as previously described in details (Ilic, D., et al., 2012, Stephenson, E., et al., 2012). The cellular area containing the ICM was then washed and transferred to plates containing mitotically inactivated human neonatal foreskin fibroblasts (HFF).
ICM plated on mitotically inactivated HFF were cultured as described (Ilic, D., et al., 2012, Stephenson, E., et al., 2012). TE cells were removed mechanically from outgrowth (Ilic, D., et al., 2007, Ilic, D., et al., 2010). hESC colonies were expanded and cryopreserved at the third passage.
Straws with the earliest frozen passage (p.2–3) are thawed and new colonies are counted three days later. These colonies are then expanded up to passage 8, at which point cells were part frozen and part subjected to standard battery of tests (pluripotency markers, in vitro and in vivo differentiation capability, genetics, sterility, mycoplasma).
Pluripotency in vitro was assessed using two different techniques: enzymatic activity assay [alkaline phosphatase (AP) assay] and immunostaining as described (Ilic, D., et al., 2012, Stephenson, E., et al., 2012).
Spontaneous differentiation into three germ layers was assessed in vitro and in vivo as described (Stephenson, E., et al., 2012, Petrova, A., et al., 2014). Targeted differentiation in cardiomyocytes followed the protocols described earlier (Laflamme, M. A., et al., 2007, Jacquet, L., et al., 2015).
DNA was extracted from hESC cultures using a Chemagen DNA extraction robot according to the manufacturer's instructions. Amplification of polymorphic microsatellite markers was carried out as described (Ilic et al., 2012). Allele sizes were recorded to give a unique fingerprint of each cell line.
aCGH was performed as described in details (Ilic et al., 2012).
SNP array was performed as described in details (Canham et al., 2015).
HLA-A, -B and -DRB1 typing was performed with a PCR sequence-specific oligonucleotide probe (SSOP; Luminex, Austin, TX, USA) hybridization protocol at the certified Clinical Transplantation Laboratory, Guy's and St Thomas' NHS Foundation Trust and Serco Plc. (GSTS) Pathology (Guy's Hospital, London, UK) as described (Jacquet et al., 2013). HLA typing was also performed independently by other group (Canham et al., 2015).
There are no competing financial interests in this study.
This work was supported by the UK Medical Research Council grants G0701172 and G0801061. We thank Dr. Yacoub Khalaf, Director of the Assisted Conception Unit of Guy's and St Thomas' NHS Foundation Trust and his staff for supporting the research program. We are especially indebted to Prof Peter Braude and patients who donated embryos.