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Abstract Background Infection with high risk Human Papilloma Virus (HPV) is associated with cancer of the cervix, vagina, penis, vulva, anus and some cases of head and neck carcinomas. The HPV derived oncoproteins E6 and E7 are constitutively expressed in tumor cells and therefore potential targets for T cell mediated adoptive immunotherapy. Effective immunotherapy is dependent on the presence of both CD4+ and CD8+ T cells. However, low precursor frequencies of HPV16 specific T cells in patients and healthy donors hampers routine isolation of these cells for adoptive transfer purposes. An alternative to generate HPV specific CD4+ and CD8+ T cells is TCR gene transfer. Methods HPV specific CD4+ T cells were generated using either a MHC class I or MHC class II restricted TCR (from clones A9 and 24.101 respectively) directed against HPV16 antigens. Functional analysis was performed by interferon-γ secretion, proliferation and cytokine production assays. Results Introduction of HPV16 specific TCRs into blood derived CD4+ recipient T cells resulted in recognition of the relevant HPV16 epitope as determined by IFN-γ secretion. Importantly, we also show recognition of the endogenously processed and HLA-DP1 presented HPV16E6 epitope by 24.101 TCR transgenic CD4+ T cells and recognition of the HLA-A2 presented HPV16E7 epitope by A9 TCR transgenic CD4+ T cells. Conclusion Our data indicate that TCR transfer is feasible as an alternative strategy to generate human HPV16 specific CD4+ T helper cells for the treatment of patients suffering from cervical cancer and other HPV16 induced malignancies.

Background: T cell receptor gene transfer is a promising strategy to treat patients suffering from HPV induced malignancies. Therefore we isolated the TCRαβ open reading frames of an HPV16E6 specific CTL clone and generated TCR transgenic T cells. In general low level expression of the transgenic TCR in recipient human T cells is observed as well as the formation of mixed TCRs dimers. Here we addressed both issues employing three different expression platforms. Methods: We isolated the HVP16E6 specific TCRα and TCRβ open reading frames and retrovirally transduced human T cells with either wild-type (wt), or codon-modified (cm) chains to achieve enhanced TCR expression levels, or used codon-modification in combination with cysteinization (cmCys) of TCRs to facilitate preferential pairing of the introduced TCRα and TCRβ chains. Results: Careful analysis of recipient T cells carrying the HPV16E6 TCRβ and endogenous TCR chains revealed the transgenic TCRβ chain to behave very promiscuously. Further analysis showed that the percentage of tetramer positive T cells in codon-modified/cysteinized TCR transgenic T cells was four-fold higher compared to wild-type and two-fold higher compared to codon-modification only. Functional activity, as determined by IFN-γ production, was high in cmCysTCR transgenic T cells, where it was low in cm and wt TCR transgenic T cells. Recognition of endogenously processed HPV16E6 antigen by cmCysTCR transgenic T cells was confirmed in a cytotoxicity assay. Conclusion: Promiscuous behavior of the HPV16E6 specific TCRβ chain can in part be forced back into specific action in TCR transgenic T cells by codon modification in combination with the inclusion of an extra cysteine in the TCR chains. [ABSTRACT FROM AUTHOR]

Recombinant adenoviruses (RAd) and recombinant vaccinia viruses (RVV) expressing tumour-associated antigens (TAA) are used as anti-tumour vaccines. It is important that these vaccines deliver the TAA to dendritic cells (DC) for the induction of a strong immune response. Infection of myeloid DC (MDC) with RAd alone is relatively inefficient but CD40 retargeting significantly increases transduction efficiency and DC maturation. Infection with RVV is efficient without DC maturation. Plasmacytoid dendritic cells (PDC) play a role in the innate immune response to viral infections through the secretion of IFNα but may also play a role in specific T-cell induction. The aim of our study was to investigate whether PDC are better targets for RAd and RVV based vaccines. RAd alone hardly infected PDC (2%) while CD40 retargeting did not improve transduction efficiency, but it did increase PDC maturation (25% CD83 positive cells). Accordingly, specific CTL activation by RAd infected PDC was limited (the number of IFNγ producing CTL was reduced by 75% compared to stimulation with peptide loaded PDC). RVV infected PDC specifically stimulated CTL but PDC were not activated. These results indicate that PDC are not ideal targets for RAd and RVV based vaccines. However, PDC induced specific CTL activation after pulsing with recombinant protein, indicating that PDC can also cross-present antigens released from surrounding infected cells. [ABSTRACT FROM AUTHOR]