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Adoptive immunotherapy with Epstein-Barr virus (EBV)-specific T cells is an effective treatment for relapsed or refractory EBV-induced post-transplant lymphoproliferative disorders (PTLD) with overall survival rates of up to 69%. EBV-specific T cells have been conventionally made by repeated stimulation with EBV-transformed lymphoblastoid cell lines (LCL), which act as antigenpresenting cells. However, this process is expensive, takes many months, and has practical risks associated with live virus. We have developed a peptide-based, virus-free, serum-free closed system to manufacture a bank of virus-specific T cells (VST) for clinical use. We compared these with standard LCL-derived VST using comprehensive characterization and potency assays to determine differences that might influence clinical benefits. Multi-parameter flow cytometry revealed that peptide-derived VST had an expanded central memory population and less exhaustion marker expression than LCL-derived VST. A quantitative HLA-matched allogeneic cytotoxicity assay demonstrated similar specific killing of EBV-infected targets, though peptide-derived EBV T cells had a significantly higher expression of antiviral cytokines and degranulation markers after antigen recall. High-throughput T cell receptor-beta (TCRb) sequencing demonstrated oligoclonal repertoires, with more matches to known EBV-binding complementary determining region 3 (CDR3) sequences in peptide-derived EBV T cells. Peptide-derived products showed broader and enhanced specificities to EBV nuclear antigens (EBNAs) in both CD8 and CD4 compartments, which may improve the targeting of highly expressed latency antigens in PTLD. Importantly, peptide-based isolation and expansion allows rapid manufacture and significantly increased product yield over conventional LCL-based approaches. [ABSTRACT FROM AUTHOR]

Dendritic cell therapy has been a promising addition to the current armory of therapeutic options in cancer for more than 20 years but has not yet achieved breakthrough success. To successfully initiate immunity, dendritic cells have to enter the lymph nodes. However, experience to date of therapeutic dendritic cell administration indicates that this is frequently an extremely inefficient process. The major regulator of dendritic cell migration to the lymph nodes is the chemokine receptor CCR7 and in vitro generated dendritic cells typically display heterogeneous expression of this receptor. Here we demonstrate that positive selection for the dendritic cell subpopulation expressing CCR7, using a chemically‐synthesized ligand:CCL19, enriches for cells with enhanced lymph node migration and Ag presentation competence as well as a chemokine expression profile indicative of improved interactions with T cells. This enhanced lymph node homing capacity of enriched CCR7+ cells is seen in comparison to a population of unsorted dendritic cells containing an equivalent number of CCR7+ dendritic cells. Importantly, this indicates that separating the CCR7+ dendritic cells from the CCR7− cells, rather than simple CCL19 exposure, is required to affect the enhanced lymph node migration of the CCR7+ cells. In models of both subcutaneous and metastatic melanoma, we demonstrate that the dendritic cells sorted for CCR7 expression trigger enhanced CD8 T‐cell driven antitumor immune responses which correlate with reduced tumor burden and increased survival. Finally, we demonstrate that this approach is directly translatable to human dendritic cell therapy using the same reagents coupled with clinical‐grade flow‐cytometric sorting. [ABSTRACT FROM AUTHOR]

Dendritic cell therapy has been a promising addition to the current armory of therapeutic options in cancer for more than 20 years but has not yet achieved breakthrough success. To successfully initiate immunity, dendritic cells have to enter the lymph nodes. However, experience to date of therapeutic dendritic cell administration indicates that this is frequently an extremely inefficient process. The major regulator of dendritic cell migration to the lymph nodes is the chemokine receptor CCR7 and in vitro generated dendritic cells typically display heterogeneous expression of this receptor. Here we demonstrate that positive selection for the dendritic cell subpopulation expressing CCR7, using a chemically-synthesized ligand:CCL19, enriches for cells with enhanced lymph node migration and Ag presentation competence as well as a chemokine expression profile indicative of improved interactions with T cells. This enhanced lymph node homing capacity of enriched CCR7+ cells is seen in comparison to a population of unsorted dendritic cells containing an equivalent number of CCR7+ dendritic cells. Importantly, this indicates that separating the CCR7+ dendritic cells from the CCR7- cells, rather than simple CCL19 exposure, is required to affect the enhanced lymph node migration of the CCR7+ cells. In models of both subcutaneous and metastatic melanoma, we demonstrate that the dendritic cells sorted for CCR7 expression trigger enhanced CD8 T-cell driven antitumor immune responses which correlate with reduced tumor burden and increased survival. Finally, we demonstrate that this approach is directly translatable to human dendritic cell therapy using the same reagents coupled with clinical-grade flow-cytometric sorting., (© 2021 The Authors. Journal of Leukocyte Biology published by Wiley Periodicals LLC on behalf of Society for Leukocyte Biology.)