They start with healthy donor fibroblasts, reprogram to create an iPSC pool and engineer using CRISPR (anti-MICA/B CAR, CD38 KO, IL-15RF and hnCD16 KI). After, comes single-cell sorting and screening of individual clones. The latter for extensive characterisation prior to master cell selection.
For that they look at clones with copy number and locus-target verification, maintain pluripotency, free of reprogramming vectors, demonstrate genomic stability, without off-target edits, ideal propensity to become NKs, as well as desired functional activity and specificity.