title: CMV-specific T cell isolation from G-CSF mobilized peripheral blood: depletion of myeloid progenitors eliminates non-specific binding of MHC-multimers.
abstract: BACKGROUND
  Cytomegalovirus (CMV)-specific T cell infusion to immunocompromised patients following allogeneic Hematopoietic Stem Cell Transplantation (allo-HSCT) is able to induce a successful anti-viral response. These cells have classically been manufactured from steady-state apheresis samples collected from the donor in an additional harvest prior to G-CSF mobilization, treatment that induces hematopoietic stem cell (HSC) mobilization to the periphery. However, two closely-timed cellular collections are not usually available in the unrelated donor setting, which limits the accessibility of anti-viral cells for adoptive immunotherapy. CMV-specific cytotoxic T cell (CTL) manufacture from the same G-CSF mobilized donor stem cell harvest offers great regulatory advantages, but the isolation using MHC-multimers is hampered by the high non-specific binding to myeloid progenitors, which reduces the purity of the cellular product.
  
  
  METHODS
  In the present study we describe an easy and fast method based on plastic adherence to remove myeloid cell subsets from 11 G-CSF mobilized donor samples. CMV-specific CTLs were isolated from the non-adherent fraction using pentamers and purity and yield of the process were compared to products obtained from unmanipulated samples.
  
  
  RESULTS
  After the elimination of unwanted cell subtypes, non-specific binding of pentamers was notably reduced. Accordingly, following the isolation process the purity of the obtained cellular product was significantly improved.
  
  
  CONCLUSIONS
  G-CSF mobilized leukapheresis samples can successfully be used to isolate antigen-specific T cells with MHC-multimers to be adoptively transferred following allo-HSCT, widening the accessibility of this therapy in the unrelated donor setting. The combination of the clinically translatable plastic adherence process to the antigen-specific cell isolation using MHC-multimers improves the quality of the therapeutic cellular product, thereby reducing the clinical negative effects associated with undesired alloreactive cell infusion.
authors.affiliation: Oncohematology Research Group, Navarrabiomed - Miguel Servet Foundation, Irunlarrea 3, 31008, Pamplona, Spain. lorea.beloki@gmail.com.
authors.forename: Lorea
authors.initials: L
authors.lastname: Beloki
authors.affiliation: Oncohematology Research Group, Navarrabiomed - Miguel Servet Foundation, Irunlarrea 3, 31008, Pamplona, Spain. miriam.ciaurriz.gortari@cfnavarra.es.
authors.forename: Miriam
authors.initials: M
authors.lastname: Ciaurriz
authors.affiliation: Oncohematology Research Group, Navarrabiomed - Miguel Servet Foundation, Irunlarrea 3, 31008, Pamplona, Spain. cristina.mansilla.puerta@cfnavarra.es.
authors.forename: Cristina
authors.initials: C
authors.lastname: Mansilla
authors.affiliation: Oncohematology Research Group, Navarrabiomed - Miguel Servet Foundation, Irunlarrea 3, 31008, Pamplona, Spain. amaya.zabalza.sanmartin@cfnavarra.es.
authors.forename: Amaya
authors.initials: A
authors.lastname: Zabalza
authors.affiliation: Oncohematology Research Group, Navarrabiomed - Miguel Servet Foundation, Irunlarrea 3, 31008, Pamplona, Spain. estela.perez.valderrama@cfnavarra.es.
authors.forename: Estela
authors.initials: E
authors.lastname: Perez-Valderrama
authors.affiliation: Department of Haematology, University College London Medical School, University College London, London, UK. edward.samuel@ucl.ac.uk.
authors.forename: Edward R
authors.initials: ER
authors.lastname: Samuel
authors.affiliation: Department of Haematology, University College London Medical School, University College London, London, UK. m.lowdell@ucl.ac.uk.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Lowdell
authors.affiliation: Oncohematology Research Group, Navarrabiomed - Miguel Servet Foundation, Irunlarrea 3, 31008, Pamplona, Spain. nramireh@navarra.es.
authors.forename: Natalia
authors.initials: N
authors.lastname: Ramirez
authors.affiliation: Oncohematology Research Group, Navarrabiomed - Miguel Servet Foundation, Irunlarrea 3, 31008, Pamplona, Spain. eduardo.olavarria.lopez@cfnavarra.es.|Department of Haematology, Complejo Hospitalario de Navarra, Navarra Health Service, Pamplona, Spain. eduardo.olavarria.lopez@cfnavarra.es.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Olavarria
mesh_terms: D003587:Cytomegalovirus / Q000276:immunology*; D005434:Flow Cytometry; D016179:Granulocyte Colony-Stimulating Factor / Q000008:administration & dosage*; D019650:Hematopoietic Stem Cell Mobilization; D006801:Humans; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D016179:Granulocyte Colony-Stimulating Factor