title: Identification of a committed T cell precursor population in adult human peripheral blood.
abstract: Here, we report data concerning the discovery in adult human peripheral blood of a precursor cell population able to differentiate into CD4+CD3+ alpha beta + mature T cells. These cells, which represent 0.1-0.5% of total peripheral blood mononuclear cells (PBMC), express substantial levels of CD4, but lack CD3 surface expression. At a molecular level, they express the pre-T cell receptor alpha (pT alpha) gene, CD3-gamma, CD-delta and CD-epsilon, and RAG-1 recombination enzyme and have initiated rearrangements in the T cell receptor (TCR)-beta locus (D-J). Moreover, low levels of CD3 epsilon protein, but not of TCR-beta chain, can be detected in their cytoplasm. Our results suggest that CD4+CD3- cells identified in peripheral blood are different from CD3-CD4+CD8- thymocytes and may contain precursors of an extrathymic T cell differentiation pathway.
authors.affiliation: Basel Institute for Immunology, Switzerland.
authors.forename: L
authors.initials: L
authors.lastname: Bruno
authors.forename: P
authors.initials: P
authors.lastname: Res
authors.forename: M
authors.initials: M
authors.lastname: Dessing
authors.forename: M
authors.initials: M
authors.lastname: Cella
authors.forename: H
authors.initials: H
authors.lastname: Spits
mesh_terms: D000328:Adult; D000818:Animals; D015703:Antigens, CD; D000943:Antigens, Differentiation; D001775:Blood Circulation; D002454:Cell Differentiation; D005434:Flow Cytometry; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D018398:Homeodomain Proteins; D006801:Humans; D008297:Male; D051379:Mice; D009924:Organ Culture Techniques; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011506:Proteins; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics / Q000302:isolation & purification*; D016176:T-Lymphocyte Subsets; D013601:T-Lymphocytes / Q000502:physiology*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology; D014158:Transcription, Genetic
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D018398:Homeodomain Proteins; D011506:Proteins; D016693:Receptors, Antigen, T-Cell, alpha-beta; C064658:RAG-1 protein