Leukoreduction system chambers are a reliable cellular source for the manufacturing of T‐cell therapeutics

Abstract

BACKGROUND Following solid organ or hematopoietic cell transplantation, refractory opportunistic viral reactivations are a significant cause of morbidity and mortality but can effectively be controlled by virus‐specific T‐cell transfer. Among effective and safe strategies is the use of “third‐party” (neither from the transplant donor nor recipient) virus‐specific T cells that can be manufactured from healthy donors and used as “off‐the‐shelf” therapies. Leukoreduction system chambers (LRSCs), recovered after routine plateletpheresis, were evaluated as a potential source of peripheral blood mononuclear cells (PBMCs) for the manufacturing of clinical‐scale virus‐specific T cell. STUDY DESIGN AND METHODS PBMCs from the same donors obtained either from LRSCs or peripheral blood were compared, focusing on T‐cell function and phenotype as well as the potential to generate cytomegalovirus (CMV)‐specific T‐cell lines from both CMV seropositive and seronegative donors. RESULTS PBMCs from both sources were comparable except for a transient downregulation of CD62L expression on freshly extracted PBMCs from LRSCs. Both nonspecific stimulation using anti‐CD3/CD28 antibodies and CMV peptides revealed that LRSCs or blood T cells were equivalent in terms of expansion, differentiation, and function. Moreover, PBMCs from LRSCs can be used to generate autologous monocyte‐derived dendritic cells to prime and expand CMV‐specific T cells from seronegative donors. CONCLUSION LRSCs are a reliable source of PBMCs for the generation of virus‐specific T cells for immunotherapy. These findings have implications for the development of third‐party therapeutic T‐cell products from well‐characterized blood product donors.

Total platelet donation count and donation frequency are determinants of plateletpheresis‐associated lymphopenia

“…Investigators have calculated different estimates for the lymphocyte content of LRS chambers, which range from about 0.6 to 1.4 × 10 9 WBC 3, 4, 11, 30, 31 . This wide variation can be explained by differences in anticoagulant ratios, device settings, draw and return management, processed blood volumes, and annual donation frequencies between studies 11, 30 .…”

“…After platelet harvesting, the trapped WBCs are flushed out of the LRS chamber (generally incompletely) and discarded or donated to research. About 1 × 10 9 WBCs can be obtained from one LRS 3, 4 . This has led to the theory that leukocyte trapping may result in leukopenia in plateletpheresis donors.…”

p16INK4a Regulates Cellular Senescence in PD-1-Expressing Human T Cells

“…Peripheral blood mononuclear cells (PBMCs) of healthy donors with the HLA-A0201 allele (for antigen-specific experiments) or various alleles (for anti-CD3/CD28 activation experiments) were obtained after informed consent by venipuncture, apheresis or leukoreduction system chambers (Héma-Québec) ( 29 ) followed by manual (Ficoll-Paque, GE Healthcare, Canada) or automated (Sepax system, Biosafe America Inc., Houston, TX) gradient density separation.…”

Co-culture Systems of Drug-Treated Acute Myeloid Leukemia Cells and T Cells for In Vitro and In Vivo Study

“…LRSCs were the waste products of plateletpheresis procedures. LRSCs are characterized by enrichment of mononuclear cells and depletion of most granulocytes and platelets ( Boudreau et al, 2019 ). The frequency of PBMCs per LRSC is approximately 0.9 × 10 9 to 1.4 × 10 9 cells with more than half are CD3 + lymphocytes ( Neron et al, 2007 ).…”