title: Characterization in vitro and engraftment potential in vivo of human progenitor T cells generated from hematopoietic stem cells.
abstract: T-cell development follows a defined set of stage-specific differentiation steps. However, molecular and cellular events occurring at early stages of human T-cell development remain to be fully elucidated. To address this, human umbilical cord blood (UCB) hematopoietic stem cells (HSCs) were induced to differentiate to the T lineage in OP9-DL1 cocultures. A developmental program involving a sequential and temporally discrete expression of key differentiation markers was revealed. Quantitative clonal analyses demonstrated that CD34(+)CD38(-) and CD34(+)CD38(lo) subsets of UCB contain a similarly high T-lineage progenitor frequency, whereas the frequency in CD34(+)CD38(+/hi) cells was 5-fold lower. Delta-like/Notch-induced signals increased the T-cell progenitor frequency of CD34(+)CD38(-/lo) cells differentiated on OP9-DL1, and 2 distinct progenitor subsets, CD34(+)CD45RA(+)CD7(++)CD5(-)CD1a(-) (proT1) and CD34(+)CD45RA(+)CD7(++)CD5(+)CD1a(-) (proT2), were identified and their thymus engrafting capacity was examined, with proT2 cells showing a 3-fold enhanced reconstituting capacity compared with the proT1 subset. Furthermore, in vitro-generated CD34(+)CD7(++) progenitors effectively engrafted the thymus of immunodeficient mice, which was enhanced by the addition of an IL-7/IL-7 antibody complex. Taken together, the identification of T-progenitor subsets readily generated in vitro may offer important avenues to improve cellular-based immune-reconstitution approaches.
authors.affiliation: Department of Immunology, University of Toronto, Toronto, ON, Canada.
authors.forename: Génève
authors.initials: G
authors.lastname: Awong
authors.forename: Elaine
authors.initials: E
authors.lastname: Herer
authors.forename: Charles D
authors.initials: CD
authors.lastname: Surh
authors.forename: John E
authors.initials: JE
authors.lastname: Dick
authors.forename: Ross N
authors.initials: RN
authors.lastname: La Motte-Mohs
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Zúñiga-Pflücker
mesh_terms: D000818:Animals; D000936:Antigen-Antibody Complex / Q000494:pharmacology; D015703:Antigens, CD / Q000032:analysis; D019070:Cell Lineage; D002478:Cells, Cultured / Q000166:cytology / Q000637:transplantation; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics; D005312:Fetal Blood / Q000166:cytology; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000235:genetics / Q000276:immunology / Q000601:surgery; D007231:Infant, Newborn; D053631:Interleukin Receptor Common gamma Subunit / Q000172:deficiency / Q000235:genetics; D015851:Interleukin-7 / Q000276:immunology / Q000494:pharmacology; D038041:Lymphopoiesis; D051379:Mice; D008807:Mice, Inbred BALB C; D016688:Mice, Inbred NOD; D018345:Mice, Knockout; D016513:Mice, SCID; D009924:Organ Culture Techniques; D013047:Specific Pathogen-Free Organisms; D016176:T-Lymphocyte Subsets / Q000737:chemistry / Q000166:cytology* / Q000637:transplantation; D013950:Thymus Gland / Q000166:cytology / Q000196:embryology; D014183:Transplantation, Heterologous
chemical_list: D000936:Antigen-Antibody Complex; D015703:Antigens, CD; D004268:DNA-Binding Proteins; C508605:IL7 protein, human; D053631:Interleukin Receptor Common gamma Subunit; D015851:Interleukin-7; C499308:Rag2 protein, mouse