FIG. 1.
Effect of LPS treatment on the production of infectious DV by young monocytes (A) and differentiated macrophages (B) cultured for 1 and 7 days, respectively. For each infection experiment, three comparison groups were included. (i) MO/Mφ were infected with DV without any stimulation (DV alone), (ii) LPS (5 or 10 μg/ml) was added to the cultures and incubated for 22 h before DV infection (LPS-DV), and (iii) LPS (5 μg/ml) was added to the cultures 6 h (A) or 12 h (B) after viral adsorption (DV-LPS). The cells were infected with DV at an MOI of 3 PFU per cell. After 42 to 46 h of infection, cells and culture supernatants were collected and assayed for both intracellular and extracellular infectious virus production. For each experimental point, triplicate wells were performed, and the results are given as the mean ± the standard error (SE).