Purification of hepatic progenitors after transduction with integrase-defective apolipoprotein A-II-green fluorescent protein (APOA-II-GFP) lentivectors. (A) Flowchart summarizing protocol for purification of hepatic progenitor cells. (B) Representative GFP fluorescence analyses of the cell population carried out on at day 16 (3 days after transduction on day 13 of differentiation with the APOA-II-GFP integrase-defective lentivector (IDLV) by immunofluorescence microscopy (left panel) and fluorescence-activated cell sorting (FACS) analysis (right panel). (C) Cytokeratin (CK)19 transcript levels in hepatic progenitors were determined immediately before and after sorting (day 13 and 16 of differentiation, respectively) by quantitative reverse transcription (qRT)-PCR analysis. (D). A phase-contrast image of human embryonic stem cells (hESC)-derived hepatic progenitors plated on type I collagen and cultured for 48 hours after sorting (magnification × 100). Immunofluorescence staining of representative fields of sorted hepatic cells treated with α-fetoprotein (AFP) (green) and CK19 (red) antibodies after 48 hours of culture on type 1 collagen.