Activation-dependent expression of the insulin-like growth factor binding protein-2 in human lymphocytes.
The expression of the insulin-like growth factor binding protein-2 (IGFBP-2) was assayed in mononuclear cells originating from different organs of the immune system. All mononuclear cells studied did express IGFBP-2, but the expression level was found to be dependent on the cell type and origin of the cell. T cells showed a higher expression of IGFBP-2 mRNA than did B cells, and CD34+ stem cells expressed IGFBP-2 mRNA at a high level. Expression was highest in bone marrow and thymus. Stimulation of peripheral mononuclear cells resulted in a marked increase of IGFBP-2 mRNA and also intracellular IGFBP-2, as analysed by fluorescence staining. This increase parallels the increase of other known T-cell activation markers. Furthermore, the increase of intracellular IGFBP-2 seems to precede T-cell blast formation and all T cells in active phases of the cell cycle have high levels of IGFBP-2. Our results provide a basis for further investigations on the contribution of the IGF-system to the regulation of T-cell proliferation and differentiation. IGFBP-2, in particular, may have an important influence in the regulation of T-cell activation and proliferation.
Föll
J L
JL
Children's University Hospital, Department of Oncology/Hematology, Tübingen, Germany.
Dannecker
L
L
Zehrer
C
C
Hettmer
S
S
Berger
J
J
Elmlinger
M
M
Niethammer
D
D
Ranke
M B
MB
Dannecker
G E
GE
D018929:Cell Culture Techniques; D002453:Cell Cycle / Q000502:physiology; D015870:Gene Expression; D006801:Humans; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000235:genetics / Q000378:metabolism*; D008213:Lymphocyte Activation / Q000502:physiology*; D016131:Lymphocyte Subsets / Q000378:metabolism*; D018613:Microscopy, Confocal; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D013601:T-Lymphocytes / Q000378:metabolism
D018971:Insulin-Like Growth Factor Binding Protein 2; D012333:RNA, Messenger