Fig. 2.

Identification of sequence elements required for inhibition of multiple HPV types. HeLa cells were pretreated with 14 µM indicated peptide for 1 h, followed by infection with HPV16 (blue), HPV18 (green), or HPV5 PsV (orange) at an MOI of 1. Peptides and PsV were left in the medium for the duration of the experiment. As a control, cells were incubated with the solution used to dissolve the peptide. At 48 h.p.i., flow cytometry was used to determine the fraction of cells expressing HcRed. The graph shows average results of three independent experiments, +/− SD, normalized to infection of each PsV type in the absence of the peptide. P16/16, P16/Tat, and P16/31 caused statistically significant (P < 0.01 or lower) inhibition of all three PsV types, which was blocked by the mutations. P values are shown for comparison of P16/16 and no peptide, P16/6A, P16/3R, and PDM/16 for HPV16 PsV. Similar levels of significance were achieved with these peptides and HPV18 and HPV5 PsV.