title: A pTalpha-negative subpopulation of CD25+ TN thymocytes revealed by a transgenic marker.
abstract: We have recently generated 5'lambda5-huTAC mice, which express the human CD25 (huTAC) gene under the control of the 5'-flanking region of the mouse lambda5-gene. The huTAC-transgene was expressed in pre-B cells but neither in mature B cells nor in T cells of these mice. In this report we demonstrate that the transgene is also transiently expressed by adult CD25+ CD3-CD4-CD8- (triple negative, TN) thymocytes and in fetal thymocytes. The huTAC+, in contrast to the huTAC- subpopulation of the CD44+CD25+ TN cells, was unexpectedly found not to express the pTalpha-gene. Still the huTAC+CD44+CD25+ TN cells reconstituted the development of both alphabeta and gammadelta lineage cells equally efficiently as the pTalpha-expressing huTAC- fraction, demonstrating that this pTalpha-negative subpopulation contained precursors for both T-cell lineages. Single cell reverse transcription-polymerase chain reaction (RT-PCR) experiments demonstrated that also in normal mice only a fraction of CD44+CD25+ and CD44-CD25+ TN cells expressed this gene. Taken together, these data indicate that huTAC transgene expression revealed a truly pTalpha-negative fraction of the CD44+CD25+ TN cells. The observation that not all precursors in the CD25+ TN population express the pTalpha-gene has important implications for the understanding of early T-cell development and T-cell lineage commitment.
authors.affiliation: Section for Immunology, Department of Cell and Molecular Biology, Lund University, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Petersson
authors.forename: A
authors.initials: A
authors.lastname: Mårtensson
authors.forename: E
authors.initials: E
authors.lastname: Mertsching
authors.forename: T
authors.initials: T
authors.lastname: Winkler
authors.forename: R
authors.initials: R
authors.lastname: Ceredig
authors.forename: I-L
authors.initials: IL
authors.lastname: Mårtensson
authors.forename: F
authors.initials: F
authors.lastname: Ivars
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D005333:Fetus / Q000166:cytology / Q000276:immunology; D015870:Gene Expression; D017930:Genes, Reporter; D005819:Genetic Markers; D006412:Hematopoietic Stem Cells / Q000276:immunology; D018960:Hyaluronan Receptors / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000276:immunology; D008562:Membrane Glycoproteins / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000378:metabolism; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000378:metabolism; D015375:Receptors, Interleukin-2 / Q000235:genetics* / Q000378:metabolism*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology
chemical_list: D005819:Genetic Markers; D018960:Hyaluronan Receptors; D008562:Membrane Glycoproteins; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta; D015375:Receptors, Interleukin-2; C090377:pre-T cell receptor alpha