Fig. 4. Characteristics of HPPL. (A) HPPL strongly expressed a laminin receptor, integrin 6ß1. Expression of integrin 6 and ß1 was analyzed by FACScaliber using FITC-conjugated anti-CD29 (integrinß1) and PE-conjugated anti-CD49f (integrin 6) mAbs (panel 2). As a negative control, HPPL were incubated with FITC-conjugated hamster IgM and PE-conjugated rat IgG (panel 1). (B) HPPL did not express Dlk. HPPL were incubated with anti-Dlk mAb followed by FITC-conjugated anti-hamster IgG (panel 2). As a negative control, HPPL were incubated with hamster IgG and FITC-conjugated anti-hamster IgG (panel 1). (C) HPPL expressed both CK19 and albumin. HPPL detached form plates were mounted on glass slides by cytospinning and incubated with anti-CK19 serum and anti-albumin antibody. The expression of CK19 and albumin were visualized with Alexa 488 anti-rabbit IgG (green in panel 1) and Alexa 555 anti-goat IgG (red in panel 2), respectively. Panel 3 is a merged image of panels 1 and 2. Bar, 10 µm. (D) TGF and p57 were upregulated and downregulated, respectively, in HPPL when compared with expression in E14.5 Dlk⁺ hepatoblasts. Gene expression was examined by RT-PCR. The thermal cycle was repeated 30 times for TGF and GAPDH, and 35 times for p57.