Ad is the most efficient vector to transduce DCs. (A) We used Ad, HIV, EIAV, and 3 MMLV constructs to generate replication-deficient Ad, HIV, EIAV, and MMLV viruses encoding (e)GFP. ITR indicates inverted terminal repeat; CMV, cytomegalovirus; LTR, long terminal repeat; cPPT, central polypurine tract cis acitve sequence; VGV, vesicular stomatitis virus; IRES, internal ribosomal entry site; and MCS, multiple cloning site. (B) The DCs were transduced with Ad, EIAV, or HIV at the MOI indicated either as iDCs (top row) or following stimulation with 20 ng/mL TNF-α, 20 ng/mL IL-1β, 20 ng/mL LPS, and 10 ng/mL PGE₂ for 48 hours (bottom row). The transfection efficiency was assessed after 5 days using flow cytometry to measure (e)GFP expression. Results are expressed as the mean ± standard deviation of triplicate determinations. (C) The ability of the 3 MMLV retroviral supernatants to infect iDCs was tested either in the presence (right column) or absence (left column) of polybrene. The transfection efficiency was assessed after 2 to 3 days using flow cytometry to measure (e)GFP expression. Percentages of (e)GFP-positive and -negative cells are shown at the bottom-left corner of each flow cytometry plot.