Tyrosine phosphorylation in peripheral T cells of kidney transplant recipients: analyses of baseline levels and response to T cell receptor stimulation.
Impaired immunosurveillance in recipients of organ transplants has been attributed to alleviation of T cell functions. We analyzed the phosphorylation of tyrosine residues in T cells of peripheral blood, and after T cell receptor (TCR) stimulation. The TCR was stimulated by OKT3 monoclonal antibody (mAb) in non-separated heparinized blood specimens of patients (n=64) and healthy controls (n=25). After fixation and red cell lysis, lymphocytes were permeabilized by saponin. Subsequently, intracellular phosphotyrosine residues and surface CD3 antigen were stained simultaneously with specific mAbs. We analyzed transplant recipients and healthy donors for baseline levels of total cellular tyrosine phosphorylation and for increase in phosphotyrosine content following stimulation by OKT3. Phosphotyrosine levels were significantly lower in non-stimulated T cells of kidney transplant recipients compared to controls (p=0.004). There was a marked variability in the levels of tyrosine phosphorylation among transplanted patients (p=0.02). T cell receptor stimulation by OKT3 mAb in vitro led to a strong increase of tyrosine phosphorylation in all specimens of patients and healthy controls. In conclusion, we demonstrated decreased phosphotyrosine levels in T cells of kidney transplant recipients compared to healthy donors. However, increase in tyrosine phosphorylation was not impaired in all patients as a result of TCR stimulation.
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Document Type: Research Article
Affiliations: Department of Internal Medicine, Internal Medicine A, University of Muenster, 48129 Muenster, Germany.
Publication date: August 1, 1999
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- The International Journal of Molecular Medicine is a monthly, peer-reviewed journal devoted to the publication of high quality studies related to the molecular mechanisms of human disease. The journal welcomes research on all aspects of molecular and clinical research, ranging from biochemistry to immunology, pathology, genetics, human genomics, microbiology, molecular pathogenesis, molecular cardiology, molecular surgery and molecular psychology.
The International Journal of Molecular Medicine aims to provide an insight for researchers within the community in regard to developing molecular tools and identifying molecular targets for the diagnosis and treatment of a diverse number of human diseases.
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