Preservation and redirection of HPV16E7-specific T cell receptors for immunotherapy of cervical cancer

Abstract

Human papilloma virus (HPV) type 16 infections of the genital tract are associated with the development of cervical cancer (CxCa) in women. HPV16-derived oncoproteins E6 and E7 are expressed constitutively in these lesions and might therefore be attractive candidates for T-cell-mediated adoptive immunotherapy. However, the low precursor frequency of HPV16E7-specific T cells in patients and healthy donors hampers routine isolation of these cells for adoptive transfer. To overcome this problem, we have isolated T cell receptor (TCR) genes from four different HPV16E7-specific healthy donor and patient-derived human cytotoxic T lymphocyte (CTL) clones. We examined whether genetic engineering of peripheral blood-derived CD8 + T cells in order to express HPV16E7 11–20-specific TCRs is feasible for adoptive transfer purposes. Reporter cells (Jurkat/MA) carrying a transgenic TCR were shown to bind relevant but not irrelevant tetramers. Moreover, these TCR-transgenic Jurkat/MA cells showed reactivity towards relevant target cells, indicating proper functional activity of the TCRs isolated from already available T cell clones. We next introduced an HPV16E7 11–20-specific TCR into blood-derived, CD8 + recipient T cells. Transgenic CTL clones stained positive for tetramers presenting the relevant HPV16E7 11–20 epitope and biological activity of the TCR in transduced CTL was confirmed by lytic activity and by interferon (IFN)-γ secretion upon antigen-specific stimulation. Importantly, we show recognition of the endogenously processed and HLA-A2 presented HPV16E7 11–20 CTL epitope by A9-TCR-transgenic T cells. Collectively, our data indicate that HPV16E7 TCR gene transfer is feasible as an alternative strategy to generate human HPV16E7-specific T cells for the treatment of patients suffering from cervical cancer and other HPV16-induced malignancies.