Figure 2

Antiproliferative effect of the anti-E7 scFvs. Proliferation of SiHa cells transduced with the 43M2N, 43M2SD, 51N, 51SD retroviruses and the pLNCX-retrovirus as a control was analyzed by CFA. Twenty-four hours post-transduction, the cells were G418-selected. After 2 weeks the cells were fixed with 20% methanol and stained with crystal violet and the colonies counted for each plate. The number of colonies was determined also for the C33A control cells transduced with the same retroviruses used in SiHa cells. Panel A: colonies obtained in a representative experiment are shown. The number of colonies in each plate was determined and expressed as a percentage of the number of cells transduced with the empty virus. Panel B: the histogram shows the mean percentage of colonies obtained from the recombinant retroviruses, ± standard deviation (SD) with respect to the control. The mean values ± SD were calculated from the results of three independent experiments performed using the HPV16-positive SiHa (in grey) or the HPV-negative C33A cells. Panel C: Analysis of cell viability by EZ4U assay. The assay is based on tetrazolium salts as indicators of cell viability. The reduction of the OD₄₅₀ value, corrected by subtracting the OD₆₂₀ value, is an indicator of cell death. SiHa cells transduced with 43M2N, 43M2SD and pLNCX retroviruses were grown in the wells of a 96-wells plate and the OD values were measured after 3 hours of incubation with the substrate. The percentage of the OD₄₅₀ values of the scFv-expressing cells, corrected for the background, is reported in the figure with respect to the control cells (pLNCX). *Statistically significant data.