THY1 and teratoma: The 201B7-1A subclone possesses an antigenic profile that is similar to the 201B7 cell line and is characterised by the undifferentiated cell surface markers Tra-1-60, Tra-1-81, Tra-2-54, human stage-specific embryonic antigen (SSEA) 3, SSEA4 and CD90 (Supplementary Fig. S1B) and the ability to differentiate into 3 germ layers, confirmed by teratoma and embryoid body formation assays (Supplementary Fig. S1 and Supplementary Table S2).