Developmental Immunology, 1993, Vol. 3, pp. 197-210
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Evolution of a CD3/CD4+ o /fl T-Cell Receptor+ Mature
T-Cell Clone from CD3-CD7/ Sorted Human Bone
Marrow Cells
HEIKE POHLA, MEDI ADIBZADEH, HANS-JORG BOHRING, PETRA SIEGELS-HOBENTHAL,
THOMAS DEIKELER, MARTIN OWSIANOWSKY, ANDREA SCHENK, ARNIKA REHBEIN,:
ELKE SCHLOTZ,: KURT SCHAUDT,: and GRAHAM PAWELEC*+:
+Medical and Natural Sciences Research Center of the University of Tibingen,
:Section for Transplantation Immunology and Immunohematology,
Division of Immunopathology, Second Department of Internal Medicine, Tfibingen University Medical Clinic, D-7400 Tibingen, Federal
Republic of Germany
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)
TCR (TCR1, ,/-specific) or WT31 (TCR2, o/fl-specific). From day 35 through day 74
in culture, the surface phenotype of this clone evolved into CD3/, CD4/, CD8-, TCR2/,
TCRI-, and was further characterized as CD2/, CD45RO/, CD16-, and CD56-. The pres-
ence of mRNA for TCR o and ]/but not ,and c chains was confirmed by Northern blot-
ting. 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 unrestric-
ted "natural killer (NK)-like" lysis of K562 target cells, with