FIG. 2.

DPPC liposomes enhance the infectivity of wild-type Ad2 (wtAd2) and augment the efficiency of rAd-mediated transfection. (A) Serially diluted Ad2 was added to A549 cells together with EYPC or DPPC liposomes (0.62 mM). At the end of a 45-min incubation period at 37°C, the virus-liposome suspension was removed and cells were cultured for an additional 20 h before being processed for indirect immunofluorescence staining. Bars indicate the means ± standard errors (n = 2). Curves representative of three independent experiments are shown. (B and C) A549 cells were transduced with rAd5-βgal (MOI = 50) in the presence of increasing concentrations of liposomes (0.025 to 0.625 mM) for 45 min at 37°C. Virus was removed, and the expression of β-galactosidase was measured 24 h later, either as the optical density of the cell monolayer measured at 630 nm (B) or after in situ X-Gal staining of methanol-fixed cells (C). Bars in panel B indicate the means ± standard errors (n = 2).