Abstract: Objective To investigate the effects of the intracellular delivery of HPV16E7_49-57 epitope modified by cell-penetrating peptide HIV-Tat_49-57 and its influential factors.Methods The unique HLA-A2+/H-2kb+ limited CTL epitope of HPV16E7 fused with a cell-penetrating sequence (HIV-Tat_49-57) was designed and a 18-mer peptide was synthesized with aid of polypeptide solid phase synthesis technique. The intracellular transport capabilities of these peptides were tested with indirect immunofluorescence assay and laser confocal microscopy.In addition,the CTL epitope and 18-met peptide were used to stimulate PBMC of healthy C57BL/6 mice,and the E7_49-57 specific CTL responses were measured by LDH cytotoxicity detection kit in PBMC of those mice.Results The HIV-Tat_49-57 peptide could efficiently assist HPV 16E7_49-57 peptide in penetrating into BHK cells in a time and dose-dependent manner (P<0.05).Furthermore,the specific CTL activity induced by the 18-mer peptide was much stronger than that induced by the single epitope.Conelusion The results show that HIV-Tat_49-57 can efficiently deliver the exogenous antigenic peptide into the cytoplasm of live cells,and induce specific CTL response.This is a new way to design peptide-based vaccine of HPV.

Key words: Gene products,tat, Epitopes,T-lymphocyte, Protein transport, Vaccines,subunit