title: PR1-specific cytotoxic T lymphocytes are relatively frequent in umbilical cord blood and can be effectively expanded to target myeloid leukemia.
abstract: PR1 is an HLA-A2 restricted leukemia-associated antigen derived from neutrophil elastase and proteinase 3, both of which are normally stored in the azurophil granules of myeloid cells but overexpressed in myeloid leukemic cells. PR1-specific cytotoxic lymphocytes (PR1-CTLs) have activity against primary myeloid leukemia in vitro and in vivo and thus could have great potential in the setting of adoptive cellular therapy (ACT). Adult peripheral blood-derived PR1-CTLs are infrequent but preferentially lyse myeloid leukemia cells. We sought to examine PR1-CTLs in umbilical cord blood (UCB) because UCB units provide a rapidly available cell source and a lower risk of graft-versus-host disease, even in the setting of mismatched human leukocyte antigen (HLA) loci.
  
  
  
  We first determined the frequency of PR1-CTLs in HLA-A2(+) UCB units and then successfully expanded them ex vivo using repeated stimulation with PR1 peptide-pulsed antigen-presenting cells (APCs). After expansion, we assessed the PR1-CTL phenotype (naive, effector, memory) and function against PR1-expressing target cells.
  
  
  
  PR1-CTLs are detected at an average frequency of 0.14% within the CD8(+) population of fresh UCB units, which is 45 times higher than in healthy adult peripheral blood. UCB PR1-CTLs are phenotypically naive, consistent with the UCB CD8(+) population as a whole. In addition, the cells can be expanded by stimulation with PR1 peptide-pulsed APCs. Expansion results in an increased frequency of PR1-CTLs, up to 4.56%, with an average 20-fold increase in total number. After expansion, UCB PR1-CTLs express markers consistent with effector memory T cells. Expanded UCB PR1-CTLs are functional in vitro as they are able to produce cytokines and lyse PR1-expressing leukemia cell lines.
  
  
  
  This study is the first report to show that T cells specific for a leukemia-associated antigen are found at a significantly higher frequency in UCB than adult blood. Our results also demonstrate specific cytotoxicity of expanded UCB-derived PR1-CTLs against PR1-expressing targets. Together, our data suggest that UCB PR1-CTLs could be useful to prevent or treat leukemia relapse in myeloid leukemia patients.
authors.affiliation: Section of Transplantation Immunology, Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Lisa S
authors.initials: LS
authors.lastname: St John
authors.affiliation: Department of Hematology, Shanghai Jiao Tong University Affiliated First People's Hospital, Shanghai, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Wan
authors.affiliation: Section of Transplantation Immunology, Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: He
authors.affiliation: Section of Transplantation Immunology, Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Haven R
authors.initials: HR
authors.lastname: Garber
authors.affiliation: Section of Transplantation Immunology, Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Clise-Dwyer
authors.affiliation: Section of Transplantation Immunology, Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Gheath
authors.initials: G
authors.lastname: Alatrash
authors.affiliation: Section of Transplantation Immunology, Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Katayoun
authors.initials: K
authors.lastname: Rezvani
authors.affiliation: Section of Transplantation Immunology, Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Shpall
authors.affiliation: Center for Cancer and Immunology Research, Children's Research Institute, Washington, DC, USA.
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Bollard
authors.affiliation: Section of Transplantation Immunology, Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Qing
authors.initials: Q
authors.lastname: Ma
authors.affiliation: Section of Transplantation Immunology, Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA. Electronic address: jmolldre@mdanderson.org.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Molldrem
mesh_terms: D000328:Adult; D000920:Antibody-Dependent Cell Cytotoxicity; D002478:Cells, Cultured; D005312:Fetal Blood / Q000166:cytology* / Q000276:immunology; D015789:HLA-A2 Antigen / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D016219:Immunotherapy, Adoptive; D020014:K562 Cells; D007951:Leukemia, Myeloid / Q000276:immunology / Q000628:therapy*; D018655:Lymphocyte Count; D053146:Myeloblastin / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism; D020298:U937 Cells
chemical_list: D015789:HLA-A2 Antigen; D053146:Myeloblastin
keywords: PR1; antigen specific cytotoxic T lymphocyte; leukemia; umbilical cord blood