title: Alterations of protein tyrosine phosphorylation in T cells of immunocompromised patients.
abstract: Activation of the T-cell receptor (TCR) results in recruitment of tyrosine kinases and changes of tyrosine phosphorylation levels. We quantitatively analyzed protein phosphorylation of resting and TCR stimulated T cells for healthy donors and immunocompromised patients using two-colour flow cytometry. Stimulation of T cells of healthy persons by OKT3 antibody led to a biphasic increase of phosphotyrosine levels with the first peak after 15 s and the absolute maximum occurring after 3-5 min. Levels remained high up to 30 min and returned to baseline levels afterwards. Compared to healthy blood donors, the phosphotyrosine baseline levels were 20-30% increased in patients after bone marrow transplantation (BMT). Using OKT3 to stimulate T cells of BMT patients led to strong increases in phosphotyrosine levels comparable to those of controls. In contrast, the response of T cells of human immunodeficiency virus-infected patients with acquired immune deficiency syndrome was severely impaired (P = 0.01). In conclusion, this flow cytometric methodology enables analyses of changes in cellular phosphotyrosine levels following TCR stimulation. The increased baseline levels in BMT patients and the observed unresponsiveness of T cells in AIDS patients could be of interest for the study of predictors of graft-versus-host reactivity and the clinical analysis of immune functions in AIDS patients, respectively.
authors.affiliation: Department of Internal Medicine A, University of Münster, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Müller
authors.forename: J
authors.initials: J
authors.lastname: Patzke
authors.forename: M
authors.initials: M
authors.lastname: Bonmann
authors.forename: M
authors.initials: M
authors.lastname: Kiehl
authors.forename: O M
authors.initials: OM
authors.lastname: Koch
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000097:blood / Q000276:immunology*; D016026:Bone Marrow Transplantation / Q000276:immunology*; D005434:Flow Cytometry; D016027:Heart Transplantation / Q000276:immunology; D006801:Humans; D016867:Immunocompromised Host / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology; D016853:Muromonab-CD3 / Q000276:immunology / Q000494:pharmacology; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*
chemical_list: D016853:Muromonab-CD3; D011506:Proteins; D019000:Phosphotyrosine