Manufacturing of highly functional and specific T cells for adoptive irnmunotherapy against virus from granulocyte colony-stimulating factor-mobilized donors

Background aims. Cytomegalovirus (CMV) reactivation remains an important risk after hematopoietic stem cell transplantation, which can be effectively controlled through adoptive transfer of donor-derived CMV-specific T cells (CMV-T). CMV-T are usually obtained from donor peripheral blood mononuclear cells (PBMCs) collected before G-CSF mobilization. Despite previous studies that showed impaired T-cell function after granulocyte colony-stimulating factor (G-CSF) mobilization, recent publications suggest that G-CSF-primed PBMCs retain anti-viral function and are a suitable starting material for CMV-T manufacturing. The objective of this study was to assess the feasibility of generating CMV-T from G-CSF mobilized donors by use of the activation marker CD 137 in comparison with conventional non-primed PBMCs. Methods. CMV-T were isolated from G-CSF mobilized and non-mobilized donor PBMCs on the basis of CMVpp65 activation-induced CD 137 expression and expanded during 3 weeks. Functional assays were performed to assess antigen-specific activation, cytokine release, cytotoxic activity and proliferation after anti-genic re-stimulation. Results. We successfully manufactured highly specific, functional and cytotoxic CMV-T from G-CSF mobilized donor PBMCs. Their anti-viral function was equivalent to non-mobilized CMV-T, and memory phenotype would suggest their long-term maintenance after adoptive transfer. Conclusions. We confirm that the use of an aliquot from G-CSF mobilized donor samples is suitable for the manufacturing of CMV cellular therapies and thereby abrogates the need for successive donations and ensures the availability for patients with unrelated donors.