Induction of Human Papillomavirus-Specific CD4⁺and CD8⁺Lymphocytes by E7-Pulsed Autologous Dendritic Cells in Patients with Human Papillomavirus Type 16- and 18-Positive Cervical Cancer

Abstract

Human papillomavirus (HPV) type 16 (HPV 16) and HPV type 18 (HPV 18) are implicated in the induction and progression of the majority of cervical cancers. Since the E6 and E7 oncoproteins of these viruses are expressed in these lesions, such proteins might be potential tumor-specific targets for immunotherapy. In this report, we demonstrate that recombinant, full-length E7-pulsed autologous dendritic cells (DC) can elicit a specific CD8+ cytotoxic T-lymphocyte (CTL) response against autologous tumor target cells in three patients with HPV 16- or HPV 18-positive cervical cancer. E7-specific CTL populations expressed strong cytolytic activity against autologous tumor cells, did not lyse autologous concanavalin A-treated lymphoblasts or autologous Epstein-Barr virus-transformed lymphoblastoid cell lines (LCL), and showed low levels of cytotoxicity against natural killer cell-sensitive K562 cells. Cytotoxicity against autologous tumor cells could be significantly blocked by anti-HLA class I (W6/32) and anti-CD11a/LFA-1 antibodies. Phenotypically, all CTL populations were CD3+/CD8+, with variable levels of CD56 expression. CTL induced by E7-pulsed DC were also highly cytotoxic against an allogeneic HLA-A2+ HPV 16-positive matched cell line (CaSki). In addition, we show that specific lymphoproliferative responses by autologous CD4+ T cells can also be induced by E7-pulsed autologus DC. E7-specific CD4+ T cells proliferated in response to E7-pulsed LCL but not unpulsed LCL, and this response could be blocked by anti-HLA class II antibody. Finally, with two-color flow cytometric analysis of intracellular cytokine expression at the single-cell level, a marked Th1-like bias (as determined by the frequency of gamma interferon- and interleukin 4-expressing cells) was observable for both CD8+ and CD4+ E7-specific lymphocyte populations. Taken together, these data demonstrate that full-length E7-pulsed DC can induce both E7-specific CD4+ T-cell proliferative responses and strong CD8+ CTL responses capable of lysing autologous naturally HPV-infected cancer cells in patients with cervical cancer. These results may have important implications for the treatment of cervical cancer patients with active or adoptive immunotherapy.

Human papillomavirus type 16 E6/E7-specific cytotoxic T lymphocytes in women with cervical neoplasia

“…However, our results do not exclude that CTL induced by vaccines or adoptive transfer will be therapeutic. Nevertheless, when designing a vaccine aiming at the induction or boosting of (pre-existing) HPV-specific mCTLp, e.g., using protein pulsed dendritic cells (Santin et al, 1999), one should consider possible local immune evasive factors.…”

Cancer immunotherapy using RNA-loaded dendritic cells

“…Direct use of previously characterized antigenic peptides is a very efficient loading strategy [11], but is restricted to a limited amount of human leucocyte antigen (HLA) type-restricted epitopes. Alternatively, DC can be pulsed with recombinant proteins to induce immune responses to all possibly derived immunogenic epitopes [12]. By using these methods, immune response will be generated to selected proteins.…”

Increase of human papillomavirus‐16 E7‐specific T helper type 1 response in peripheral blood of cervical cancer patients after radiotherapy

“…8,9 In addition, specific cytotoxic T-cell and T helper activity to E6 and E7 from HPV-16 and HPV-18 have been demonstrated in peripheral blood from patients with premalignant cervical neoplasias, and it has been suggested that spontaneous regression of cervical intraepithelial neoplasia lesions might be associated with these immune responses. [10][11][12] Analysis of T helper type 1 (Th1) and type 2 (Th2) cytokine profiles has been used to characterize the immune response in several human diseases, including HPV-associated diseases. 13,14 Some of these studies have shown that, during carcinogenesis in the cervical epithelia, a shift from Th1 to Th2 cytokines is observed.…”