Isolation of highly suppressive CD25+FoxP3+ T regulatory cells from G-CSF-mobilized donors with retention of cytotoxic anti-viral CTLs: application for multi-functional immunotherapy post stem cell transplantation

• Published in: PloS one Vol. 9; no. 1; p. e85911
• Main Authors: Samuel, Edward R, Beloki, Lorea, Newton, Katy, Mackinnon, Stephen, Lowdell, Mark W
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 17.01.2014; Public Library of Science (PLoS)
• Subjects: Activation; Adoptive immunotherapy; Adoptive transfer; Antiviral agents; Apheresis; Biology; CD25 antigen; CD4 antigen; CD8 antigen; Cell culture; Cell proliferation; Cell Proliferation - drug effects; Cell Separation; Cytokines - secretion; Cytomegalovirus; Cytomegalovirus - drug effects; Cytomegalovirus infections; Cytotoxicity; Data collection; Data processing; Feasibility; Feasibility studies; Forkhead Transcription Factors - metabolism; Foxp3 protein; Good Manufacturing Practice; Graft-versus-host reaction; Granulocyte colony-stimulating factor; Granulocyte Colony-Stimulating Factor - pharmacology; Health aspects; Hematopoietic Stem Cell Mobilization; Hematopoietic Stem Cell Transplantation; Hematopoietic stem cells; Humans; Immunomagnetic Separation; Immunoregulation; Immunotherapy; Interleukin 10; Interleukin-2 Receptor alpha Subunit - metabolism; Leukapheresis; Lymphocytes; Lymphocytes T; Manufacturing; Medicine; Phosphoproteins - metabolism; Procurement; Species Specificity; Stem cell transplantation; Stem cells; Stimulation; T cell receptors; T cells; T-Lymphocytes, Cytotoxic - cytology; T-Lymphocytes, Cytotoxic - drug effects; T-Lymphocytes, Cytotoxic - metabolism; Tissue Donors; Transplantation; Transplantation, Autologous; Viral Matrix Proteins - metabolism; United Kingdom > UK
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0085911

Previous studies have demonstrated the effective control of cytomegalovirus (CMV) infections post haematopoietic stem cell transplant through the adoptive transfer of donor derived CMV-specific T cells (CMV-T). Strategies for manufacturing CMV immunotherapies has involved a second leukapheresis or blood draw from the donor, which in the unrelated donor setting is not always possible. We have investigated the feasibility of using an aliquot of the original G-CSF-mobilized graft as a starting material for manufacture of CMV-T and examined the activation marker CD25 as a targeted approach for identification and isolation following CMVpp65 peptide stimulation. CD25+ cells isolated from G-CSF-mobilized apheresis revealed a significant increase in the proportion of FoxP3 expression when compared with conventional non-mobilized CD25+ cells and showed a superior suppressive capacity in a T cell proliferation assay, demonstrating the emergence of a population of Tregs not present in non-mobilized apheresis collections. The expansion of CD25+ CMV-T in short-term culture resulted in a mixed population of CD4+ and CD8+ T cells with CMV-specificity that secreted cytotoxic effector molecules and lysed CMVpp65 peptide-loaded phytohaemagglutinin-stimulated blasts. Furthermore CD25 expanded cells retained their suppressive capacity but did not maintain FoxP3 expression or secrete IL-10. In summary our data indicates that CD25 enrichment post CMV stimulation in G-CSF-mobilized PBMCs results in the simultaneous generation of both a functional population of anti-viral T cells and Tregs thus illustrating a potential single therapeutic strategy for the treatment of both GvHD and CMV reactivation following allogeneic haematopoietic stem cell transplantation. The use of G-CSF-mobilized cells as a starting material for cell therapy manufacture represents a feasible approach to alleviating the many problems incurred with successive donations and procurement of cells from unrelated donors. This approach may therefore simplify the clinical application of adoptive immunotherapy and broaden the approach for manufacturing multi-functional T cells.