FIG. 3.
CARex-Fc-Ad-induced transduction and endocytosis of THP-1 cells are largely independent of cRGD peptides. (A) THP-1 cells (5 × 105 in 0.5 ml) expressing very low levels of αv integrins (42) were preincubated with or without 0.2 mM cRGD or 0.2 mM NLS control peptides for 30 min at 37°C, followed by incubation with Ad5-eGFP CARex-Fc mixtures (0.9 μg of Ad5; 300 dimers/Ad particle) for 60 min in the cold. Under these conditions, about 5% of the input virus was bound, corresponding to an MOT of 35. The cells were washed and incubated in warm medium for 24 h and then subjected to flow cytometry for eGFP measurements. The means of three independent experiments are shown, including standard deviations. (B) THP-1 cells (5 × 105) pretreated with or without 0.5 mM cRGD peptides were incubated with Ad2 (13.5 μg) that had been preloaded with CARex-Fc at a ratio of 120 dimers/Ad particle in the cold for 60 min (MOT = 300). The cells were washed, warmed at 37°C for 5 min, pulsed with dextran-FITC (1 mg/ml) at 37°C for 5 min, and analyzed by flow cytometry. The results are expressed as levels of stimulation of dextran uptake compared to uninfected cells. Results for one of three representative experiments are shown.