title: Thymopoiesis independent of common lymphoid progenitors.
abstract: Early T lineage progenitors (ETPs) in the thymus are thought to develop from common lymphoid progenitors (CLPs) in the bone marrow (BM). We compared thymic ETPs to BM CLPs in mice and found that they differed in several respects. Thymic ETPs were not interleukin 7 (IL-7)-responsive and generated B lineage progeny with delayed kinetics, whereas BM CLPs were IL-7-responsive and rapidly generated B cells. ETPs sustained production of T lineage progeny for longer periods of time than BM CLPs. Analysis of Ikaros-deficient mice that exhibit ongoing thymopoiesis without B lymphopoeisis revealed near-normal frequencies of thymic ETPs, yet undetectable numbers of BM CLPs. We conclude that ETPs can develop via a CLP-independent pathway.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104-6160, USA.
authors.forename: David
authors.initials: D
authors.lastname: Allman
authors.forename: Arivazhagan
authors.initials: A
authors.lastname: Sambandam
authors.forename: Sungjune
authors.initials: S
authors.lastname: Kim
authors.forename: Juli P
authors.initials: JP
authors.lastname: Miller
authors.forename: Antonio
authors.initials: A
authors.lastname: Pagan
authors.forename: David
authors.initials: D
authors.lastname: Well
authors.forename: Anita
authors.initials: A
authors.lastname: Meraz
authors.forename: Avinash
authors.initials: A
authors.lastname: Bhandoola
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology; D001854:Bone Marrow Cells / Q000166:cytology / Q000276:immunology; D004268:DNA-Binding Proteins; D005260:Female; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology*; D051740:Ikaros Transcription Factor; D015851:Interleukin-7 / Q000494:pharmacology; D007700:Kinetics; D038041:Lymphopoiesis / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D013601:T-Lymphocytes / Q000166:cytology* / Q000187:drug effects / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics / Q000276:immunology
chemical_list: D004268:DNA-Binding Proteins; D015851:Interleukin-7; D014157:Transcription Factors; C497238:Zfpn1a1 protein, mouse; D051740:Ikaros Transcription Factor