Identification of HLA-AI I-restricted CTL epitopes derived from HPV type 18 using DNA immunization

摘要

Identification of the cytotoxic T lymphocyte (CTL) epitopes of tumor antigens is important for effective immunotherapy.We report that a combination of epitope prediction, enzyme-linked immunosorbent assay (ELISA)-based epitope-HLA complex formation, and DNA immunization methods can improve the efficiency and accuracy of CTL epitope studies. In this study, two HLA-AI I-restricted epitopes derived from human papillomavirus (HPV) 18 E6 oncoprotein were identified. HLA-AI I-transgenic mice immunized with these epitopes could specifically induce interferon-y (IFNy) production, cytotoxicity and peptide/HLA-AI I tetramer binding in CD8+T-cells.To study intracellular processing of CTL epitopes, we constructed a DNA plasmid containing an endoplasmic reticulum (ER) targeting sequence as well as the HPV 18 E6 and E7 genes (pEK/HP-V18E6E7). CTL responses against peptide-pulsedT2/AI I cells could be detected after immunizing HLA-A11 -transgenic mice with pEK/HPVI8E6E7. Furthermore, the identified peptides could stimulate T-cells to secrete IFNy from HPVI8-infected patients. Our results demonstrate that the antigenic E6 peptides derived from HPV 18 are potential candidates for the treatment of HPV 18-associated tumors in HLA-AI l+ populations.