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Characterization of the Insulin‐Like Growth Factor Axis in the Human Thymus
Author(s) -
Ouafae Kecha,
Henri Martens,
Nathalie Franchimont,
Imane Achour,
M. T. Hazee-Hagelstein,
Chantal Charlet-Renard,
Vincent Geenen,
Rose Winkler
Publication year - 1999
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1046/j.1365-2826.1999.00343.x
Subject(s) - jurkat cells , biology , growth factor , insulin like growth factor , medicine , receptor , endocrinology , microbiology and biotechnology , t cell , northern blot , tec , messenger rna , reverse transcriptase , gene , immunology , immune system , polymerase chain reaction , genetics , ionosphere , physics , astronomy
The components of the insulin‐like growth factor (IGF) axis have been investigated in the normal human thymus. Using ribonuclease protection assays (RPA), IGF‐II transcripts were detected in the normal human thymus. By reverse transcriptase polymerase chain reaction (RT‐PCR) analyses, promoters P3 and P4 were found to be active in the transcription of IGF2 gene within human thymic epithelial cells (TEC). No IGF‐II mRNA could be detected in human lymphoid Jurkat T cells with 30 cycles of RT‐PCR. By Northern blot analyses, IGFBP‐2 to ‐6 (but not IGFBP‐1) were found to be expressed in TEC with a predominance of IGFBP‐4. Interestingly, Jurkat T cells only express IGFBP‐2 but at high levels. The type 1 IGF receptor was detected in Jurkat T cells but not in human TEC. The identification of the components of the IGF axis within separate compartments of the human thymus adds further evidence for a role of this axis in the control of T‐cell development. The precise influence of thymic IGF axis upon T‐cell differentiation and immunological self‐tolerance however needs to be further investigated.