title: Identification of checkpoints in human T-cell development using severe combined immunodeficiency stem cells.
abstract: BACKGROUND
  Severe combined immunodeficiency (SCID) represents congenital disorders characterized by a deficiency of T cells caused by arrested development in the thymus. Yet the nature of these developmental blocks has remained elusive because of the difficulty of taking thymic biopsy specimens from affected children.
  
  
  OBJECTIVE
  We sought to identify the stages of arrest in human T-cell development caused by various major types of SCID.
  
  
  METHODS
  We performed transplantation of SCID CD34(+) bone marrow stem/progenitor cells into an optimized NSG xenograft mouse model, followed by detailed phenotypic and molecular characterization using flow cytometry, immunoglobulin and T-cell receptor spectratyping, and deep sequencing of immunoglobulin heavy chain (IGH) and T-cell receptor δ (TRD) loci.
  
  
  RESULTS
  Arrests in T-cell development caused by mutations in IL-7 receptor α (IL7RA) and IL-2 receptor γ (IL2RG) were observed at the most immature thymocytes much earlier than expected based on gene expression profiling of human thymocyte subsets and studies with corresponding mouse mutants. T-cell receptor rearrangements were functionally required at the CD4(-)CD8(-)CD7(+)CD5(+) stage given the developmental block and extent of rearrangements in mice transplanted with Artemis-SCID cells. The xenograft model used is not informative for adenosine deaminase-SCID, whereas hypomorphic mutations lead to less severe arrests in development.
  
  
  CONCLUSIONS
  Transplanting CD34(+) stem cells from patients with SCID into a xenograft mouse model provides previously unattainable insight into human T-cell development and functionally identifies the arrest in thymic development caused by several SCID mutations.
authors.affiliation: Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Anna-Sophia
authors.initials: AS
authors.lastname: Wiekmeijer
authors.affiliation: Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Karin
authors.initials: K
authors.lastname: Pike-Overzet
authors.affiliation: Department of Immunology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Hanna
authors.initials: H
authors.lastname: IJspeert
authors.affiliation: Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Martijn H
authors.initials: MH
authors.lastname: Brugman
authors.affiliation: Department of Immunology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Ingrid L M
authors.initials: IL
authors.lastname: Wolvers-Tettero
authors.affiliation: Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Arjan C
authors.initials: AC
authors.lastname: Lankester
authors.affiliation: Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Robbert G M
authors.initials: RG
authors.lastname: Bredius
authors.affiliation: Department of Immunology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Jacques J M
authors.initials: JJ
authors.lastname: van Dongen
authors.affiliation: Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Willem E
authors.initials: WE
authors.lastname: Fibbe
authors.affiliation: Department of Immunology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Anton W
authors.initials: AW
authors.lastname: Langerak
authors.affiliation: Department of Immunology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Mirjam
authors.initials: M
authors.lastname: van der Burg
authors.affiliation: Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: f.j.t.staal@lumc.nl.
authors.forename: Frank J T
authors.initials: FJ
authors.lastname: Staal
mesh_terms: D000818:Animals; D000954:Antigens, Surface / Q000378:metabolism; D001402:B-Lymphocytes / Q000166:cytology / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D005260:Female; D015321:Gene Rearrangement; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology; D064593:Heterografts; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D016130:Immunophenotyping; D054503:Lymphoid Progenitor Cells / Q000166:cytology / Q000378:metabolism; D051379:Mice; D016688:Mice, Inbred NOD; D008822:Mice, Transgenic; D009154:Mutation; D010641:Phenotype; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000378:metabolism; D016511:Severe Combined Immunodeficiency / Q000209:etiology*; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism*; D013601:T-Lymphocytes / Q000166:cytology* / Q000378:metabolism*; D013950:Thymus Gland / Q000196:embryology
chemical_list: D000954:Antigens, Surface; D007143:Immunoglobulin Heavy Chains; D011948:Receptors, Antigen, T-Cell
keywords: Artemis; B-cell development; IL2RG; IL7RA; NSG; SCID; T-cell development; adenosine deaminase; thymus