Analysis of the expression of the transfected vectors in control or induced 18-4s cells. (A). Analysis of the expression of NefG3C-GFP and ΔNGFr in non induced 18-4s cells. Seven days after the last cell sorter purification step, the cells were labeled with unspecific IgG (I) or with anti-human NGFr mAb (II) and analyzed by FACs. Quadrants were set on the basis of the fluorescence levels of 293/RGP cells labeled with anti-NGFr mAb. (B) FACs analysis for the expression of both NefG3C-GFP and HIV-1 CAp24-related products in 18-4s cells treated with: i) 2 μM PonA; ii) 2 μM PonA and 5 mM sodium butyrate for one day and, thereafter, with 2 μM PonA alone, or iii) 2 μM PonA and 5 mM sodium butyrate. The cells harvested two days after the induction were permeabilized and labeled with a 1:100 dilution of the anti-CAp24 KC-57 PE-conjugated mAb. 293/RGP cells were used as control. Both the percentages and the mean fluorescence values referred to CAp24- and, in the case of 18-4s cells, also to the GFP-related fluorescence are reported in the respective quadrants. NaB: sodium butyrate. The results are representative of 3 independent experiments.