Figure 2. Flow cytometric analysis of SSEA-4 expression in cultured limbal stromal cells. A: Isolation of SSEA-4⁺ and SSEA-4^- limbal stromal cells at passage (P) 1 by FACS. Cell debris and doublets were discriminated before cell sorting as shown in the first three panels. Gating hierarchy was shown in the table. Percentages of pre- and post-sorted cells are also depicted in histograms. The sorted SSEA-4⁺ and SSEA-4^- cells were cultured separately. B: Propagated cells after cell sorting were re-analyzed for the expression of SSEA-4 at P2 and P4 (C). Expression of SSEA-4 in hESC is also demonstrated. The green line in the histograms represents the isotype control.