Figure 2.

IPCs and DCs developed in culture from huFlt3-transduced Flt3⁻ progenitors are functional. (A) Contour plots indicate surface markers (closed histogram) and respective isotype controls (open histogram) on CD11c⁺B220⁺ and CD11c⁺B220⁻ cells derived from huFlt3L-Ig– and SCF-cultured huFlt3-transduced Flt3⁻ progenitors. CD11c⁺B220⁺ and CD11c⁺B220⁻ cells show typical phenotypes of IPCs and DCs, respectively. Results are from one representative experiment out of three. (B) Sorted CD11c⁺B220⁺ IPCs but not CD11c⁺B220⁻ DCs, both derived from either huFlt3-transduced Flt3⁻ progenitors or GFP-transduced Flt3⁺ progenitors, produce IFN-α upon influenza virus or CpG stimulation. Culture supernatants were collected after 24 h and analyzed by ELISA. Results are from one representative experiment out of three. (C) About half of day 8 progeny from huFlt3-transduced Flt3⁻ progenitors display typical DC morphology. Giemsa-stained cytospin, photographed at a magnification of 40. (D) In vitro–generated CD11c⁺B220⁻ cells from retrovirus-transduced progenitors are efficient stimulators of allogeneic T cells. Graph depicts thymidine incorporation of 2 × 10⁵ allogeneic BALB/c spleen CD4⁺ T cells incubated with graded numbers (x axis) of sorted CD11c⁺B220⁻ DCs derived from huFlt3-transduced Flt3⁻ progenitors (•), CD11c⁺B220⁺ IPCs derived from huFlt3-transduced Flt3⁻ progenitors (▪), or CD11c⁺B220⁻ DCs derived from GFP-transduced Flt3⁺ progenitors (△), and CD11c⁺B220⁺ IPCs derived from GFP-transduced Flt3⁺ progenitors (⋄). Results are from one representative experiment out of three.