Dendritic cells transduced by a rearranged HPV-16 E7 DNA vaccine induces in vitro E7 wildtype-specific human T cells

Objective: An artificial („shuffled“) HPV-16 E7-gene (HPV-16 E7SH) was constructed, providing all potential cytotoxic T-lymphocyte (CTL) epitopes. The E7SH-gene is immunogenic in the murine system and able to induce tumor regression. In soft-agar transformation assays no transforming properties are detectable. To test for its immunogenicity in human initial in vitro studies were performed. Methods: Autologous monocyte-derived dendritic cells (DCs) were transfected by Amaxa nucleofection technology. Expression of the antigen was verified by RT-PCR and Western blotting. T-cell-lines specific for HPV-16 E7 were restimulated or naive T-cells primed with nucleofected DC. Responses were measured by IFN-α ELISpot, proliferation, and cytotoxicity assays. Results: HPV-16 E7WT specific T-cell-lines were restimulated with HPV-16 E7SH-DNA transfected DCs. Cell-lines (3/4) showed a significant specific INF-α release in ELISpot-assays (p<0.01). HPV-16 E7SH primed T-cell-lines could be restimulated by HPV-16 E7WT peptide loaded DCs. In proliferation assays 3/4 T cell lines reacted specifically (p<0.01) and 2/3 T-cell-lines showed specific lysis of target cells. While peptide generated T-cell-lines contained 60–80% CD4+ T-cells, DNA-nucleofection primed T-cell-lines had 50–70% CD8+ T-cells. Discussion: We show that the artificial HPV-16 E7SH-gene may be immunogenic in humans. Induced CTLs recognized E7WT antigen and were functionally active. The DNA-vaccine primarily induces CD8+ T-cells what might be advantageous for a therapeutic vaccine against cervical cancer.

Eingereicht von: Dr. Peter Öhlschläger

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