Induction of tumor-specific cytotoxicity in tumor infiltrating lymphocytes by HPV16 and HPV18 E7-pulsed autologous dendritic cells in patients with cancer of the uterine cervix

Abstract

Objective To evaluate the potential of autologous dendritic cells (DC) pulsed with HPV16 and HPV18 E7 oncoprotein in restoring tumor-specific cytotoxicity in populations of tumor infiltrating lymphocytes (TIL) for adoptive immunotherapy of cervical cancer patients. Methods Full-length E7-pulsed DC-stimulated CD8 + T cells derived from peripheral blood (PBL) and from tumor tissues (TIL) were tested and compared for their ability to induce a HLA class-I-restricted cytotoxic T lymphocyte (CTL) response against autologous tumor cells. In addition, in order to correlate cytotoxic activity by CTL with a particular lymphoid subset, analysis of surface antigens and intracellular CD3 ζ chain and two-color flow cytometric analysis of intracellular cytokine expression (IFN-γ vs IL-4) at the single cell level were performed. Results DC stimulation induced powerful cytotoxicity against autologous tumor target cells by TIL-derived CD8 + T cells from all three cervical cancer patients, while autologous Epstein–Barr virus-transformed lymphoblastoid cell lines were not lysed. Killing of autologous tumor cells was higher by CD8 + T cells from TIL compared to PBL ( P > 0.01) and was more strongly inhibited by anti-HLA class I MAb ( P > 0.05). Phenotypically, all CTL populations were CD3 +/CD8 +, with higher levels of CD56 expression by TIL-derived CTL. Finally, although a marked Type 1 cytokine bias (i.e., IFN-γ high/IL-4 low) was observable in both PBL- and TIL-derived DC-stimulated CD8 + T cell populations, TIL-derived CD8 + T cells showed a higher percentage of IFN-γ-positive cells compared to PBL. Conclusions Full-length E7-pulsed DC can consistently restore strong CD8 + CTL responses against autologous HPV16- and HPV18-infected cervical cancer cells. DC-stimulated TIL may represent a superior source of tumor-specific CTL compared to PBL for adoptive T cell immunotherapy of patients harboring metastatic or recurrent cervical cancer refractory to standard treatment modalities.