title: CD34-positive early human thymocytes: T cell receptor and cytokine receptor gene expression.
abstract: CD34, a stem cell marker, has been shown to be expressed on human CD3-CD4-CD8- (triple-negative; TN) thymocytes. Phenotypic and functional analyses suggest the following differentiation sequence: CD34+1-3-4-8(-)--> CD34+1+3-4 +/- 8(-)-->CD34-1+3-4+8(+/-)-->CD34-1++3-4+8+. In this report, we examined cytokine receptor gene expression on these subsets by reverse transcription-polymerase chain reaction analysis (RT-PCR). We were able to detect interleukin-7 receptor (IL-7R), c-kit and IL-2R gamma in all CD34+ thymocyte subsets, consistent with previous functional studies. We found IL-1R, granulocyte/macrophage colony-stimulating factor receptor-alpha and IL-4R transcripts in CD3- and CD34+ subsets. Secondly, we investigated T cell receptor (TCR)-delta and -beta gene rearrangement and transcription in CD34+ thymocytes. Our results show that a full-length TCR-delta transcript and the recombination activating genes RAG-1 and RAG-2 mRNA were already expressed in the CD34+1- subset. Mature V beta-containing TCR transcripts were also detected in the CD34+1+ subset, but not in the CD1- fraction. Furthermore, PCR analysis of D-J beta gene rearrangements showed that > or = 70% of CD34+1- cells are in a TCR beta germ-line configuration, although D-J beta recombination had already started in this population.
authors.affiliation: Laboratoire d'Immunologie Cellulaire et Tissulaire, CNRS URA 625, Hôpital de la Pitié-Salpétrière, Paris, France.
authors.forename: S
authors.initials: S
authors.lastname: Ktorza
authors.forename: S
authors.initials: S
authors.lastname: Sarun
authors.forename: F
authors.initials: F
authors.lastname: Rieux-Laucat
authors.forename: J P
authors.initials: JP
authors.lastname: de Villartay
authors.forename: P
authors.initials: P
authors.lastname: Debré
authors.forename: C
authors.initials: C
authors.lastname: Schmitt
mesh_terms: D018952:Antigens, CD34 / Q000096:biosynthesis*; D001483:Base Sequence; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D004247:DNA / Q000032:analysis; D015870:Gene Expression; D006801:Humans; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011948:Receptors, Antigen, T-Cell / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D018121:Receptors, Cytokine / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology* / Q000378:metabolism
chemical_list: D018952:Antigens, CD34; D011948:Receptors, Antigen, T-Cell; D018121:Receptors, Cytokine; D004247:DNA