Fig. 1

Generation of the E7/HPV16-eGFP conditional mouse model. A Schematic drawing of the targeting strategy. Before Cre-mediated recombination, the E7/HPV16-eGFP allele (E7^inv allele) is in antisense from the pCAG promoter. After Cre-mediated recombination, the E7/HPV16-eGFP is expressed (E7⁺ allele). Lox66 and lox71 were used to reduce Cre-mediated reversion from the E7 allele to the E7^inv allele [55]. B The expression of the E7/HPV16-eGFP construct was validated by GFP fluorescence before (E7^inv/wt) and after (E7⁺/wt) Cre recombinase-mediated inversion in mutant ES cells and wild-type ES control cells (wt/wt). C IM injection of Cre LentiFlash^® was performed in E7^inv/wt mice at day 0 to locally induce E7/HPV16-eGFP expression. The detection of the local expression of green fluorescence was realized with the MiniZ probe using the Cellvizio^® system at 488 nm, from day 2 to 7. One image was extracted from each video to visualize the fluorescence expression at the injected point in comparison with the non-injected (NI) point. D The mean fluorescence intensity values (± SD) are shown. The fluorescence intensity was calculated as the mean of the fluorescence intensity of the totality of every point captured during the video for each animal (individual dot). When several mice were tested at the same time, the means of the results for each mouse were calculated. E The mean ± SD of the number of IFN-y SFC per 10⁶ cells is shown for both control and Cre LentiFlash^® Cre mouse groups. Splenocytes were collected from the NI mice (control group) and at 8 days after Cre particle injection (Cre LentiFlash^® group) and were stimulated in triplicate to evaluate the T-cell response against the HPV16 E7 116-2jc peptide by IFN-y ELISpot assay. For each mouse, the number of spot-forming cells (SFC) corresponds to the median of triplicates and was corrected with the negative control. One-tailed Wilcoxon test was used (*p value < 0.05)