Rapid Generation of Full Clinical-Grade Human Antiadenovirus Cytotoxic T Cells for Adoptive Immunotherapy

Adenovirus (ADV) infections are one of the major causes of morbidity and mortality after hematopoietic stem cell transplantation, despite new antiviral treatment strategies. We describe here a complete clinical-grade generation of human anti-ADV cytotoxic T cells to propose an adoptive immunotherapy. Peripheral blood mononuclear cells (PBMC) from 7 healthy donors, known for their good cellular immunity against ADV, were stimulated for 6 hours with a synthetic peptide pool covering the ADV5 Hexon protein interferon-gamma (IFN-gamma) secreting cells were isolated on a clinical device. After immunoselection, a mean number of 1.01 +/- 0.84 x 10(6) total nucleated cells was obtained. The isolated ADV-specific T cells were mainly CD4+ (mean=56% +/- 20.8%, yield=51% +/- 32.4%) but also CD8+ (mean=42% +/- 27%, yield = 56% +/- 39.3%). Isolated T lymphocytes (CTL) were expanded to carry out functional tests. Ability of the expanded CTL to secrete IFN-gamma and to proliferate after restimulation with the ADV peptide pool was confirmed. A high cytotoxicity against autologous target cells loaded with ADV antigens was observed but not against nonloaded target cells. We observed a decrease of 1.27 log of the allogeneic reaction against non HLA identical healthy donor PBMC with CTL compared with the PBMC before selection. Clinical-grade generation of ADV-specific T cells was achieved with a synthetic antigen. This technology has the advantage of being fast, and is sufficiently reactive to be proposed for immunotherapy if antiviral treatment fails.