Table of Contents Author Guidelines Submit a Manuscript
Developmental Immunology
Volume 3, Issue 3, Pages 197-210

Evolution of a CD3+/CD+α/ β T-Cell Receptor+ Mature T-Cell Clone from CD3-CD7+ Sorted Human Bone Marrow Cells

1Medical and Natural Sciences Research Center of the University of Tübingen, Tübingen University Medical Clinic, Tübingen D-7400, Germany
2Section for Transplantation Immunology and Immunohematology, Tübingen University Medical Clinic, Tübingen D-7400, Germany
3Division of Immunopathology, Second Department of Internal Medicine, Tübingen University Medical Clinic, Tübingen D-7400, Germany
4Department of Dermatology, Klinikum Steglitz, Berlin, Germany
5Abt. Innere Medizin II, Medizinische Universitätsklinik und Poliklinik, Tübingen D-7400, Germany

Received 5 August 1992; Accepted 10 December 1992

Copyright © 1993 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In order to study extrathymic differentiation in vitro, CD7+CD3- lymphocytes were sorted from normal human bone marrow and cultured under conditions of limiting dilution together with irradiated pooled allogeneic peripheral blood mononuclear cells (PBMC) and phytohemagglutinin (PHA) in the presence of 1000 U/ml of interleukin-2 (IL-2). One clone was obtained that failed to react with monoclonal antibody (mAb) TCRδ1 (TCRγ/δ-specific) or WT31 (TCR2, α/β-specific). From day 35 through day 74 in culture, the surface phenotype of this clone evolved into CD3+, CD4+, CD8-, TCR2+, TCR1-, and was further characterized as CD2+, CD45RO+, CD16-, and CD56-. The presence of mRNA for TCR α and γ but not ,and γ chains was confirmed by Northern blotting. Accessory cell-dependent autocrine proliferative responses to PHA (most likely driven by IL-2) were initially absent, but became measurable at the same time as the TCR was acquired. However, in the absence of PHA, the clone failed to respond to a panel of homozygous B-cell lines representing the majority of MHC class II alleles. Autoreactivity was also not demonstrable. Cytotoxicity was limited to MHC unrestricted “natural killer (NK)-like” lysis of K562 target cells, with no autocytotoxicity detected. Tle NK-like lysis diminished over time in parallel with the acquisition of surface TCR. The cloned cells were not suppressive for mature lymphocyte proliferation. After stimulation, the cells secreted tumor necrosis factor α and granulocyte/macrophage colony-stimulating factor (GM-CSF) detected by immunoassays, and T-cell growth factors, most likely IL-2, as detected by bioassays. Polymerase chain-reaction methods demonstrated the presence of mRNA for IL-2, IL-3, IL-4, IL-9, interferon-δ, and GM-CSF in these cells after stimulation with PHA and B-LCL.

These results suggest that cells with the phenotype and some functional characteristics of mature T lymphocytes can evolve extrathymically in vitro from T-cell precursors sorted from normal human bone marrow.