Protein kinase C-dependent up-regulation of CD5 surface expression on normal and lymphoblastoid T cells.
As an approach to study the mechanisms regulating the surface expression of CD5 antigen on T cells, the effects of agents that activate different lymphocyte functions were examined. Active tumour promoter agents (TPA), such as phorbol ester analogues [phorbol 12-myristate 13-acetate (PMA), phorbol 12, 13-dibutyrate (PBu2)] and mezerein, were able to increase the expression of CD5 on the cell surface of all T-cell lines), as deduced from immunofluorescence and immunoprecipitation analysis. The TPA-induced CD5 up-regulation occurred in a dose-and time-dependent manner and was dependent on protein and RNA synthesis. From the other stimuli tested, the T-cell mitogens [phytohaemagglutinin (PHA) and concanavalin A (Con A)], as well as monoclonal antibodies (mAb) against the CD3 complex, also increased CD5 expression, although to a lesser degree. In all cases the increments were shown to be dependent on protein kinase C (PKC), as evidenced by their inhibition with staurosporine, a potent inhibitor of PKC activation. These data suggest that CD5 up-regulation on T cells can be a physiological event that depends on PKC activation.
Servei d'Immunologia, Hospital Clinic i Provincial de Barcelona, Spain.
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Lozano
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Alberola-Ila
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Places
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Gallart
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Vives
D000943:Antigens, Differentiation / Q000032:analysis*; D018956:CD5 Antigens; D002460:Cell Line; D002648:Child; D004306:Dose-Response Relationship, Immunologic; D006801:Humans; D007700:Kinetics; D007942:Leukemia, Experimental / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D008934:Mitogens / Q000276:immunology; D011493:Protein Kinase C / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000943:Antigens, Differentiation; D018956:CD5 Antigens; D008934:Mitogens; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate