title: Tyrosine phosphorylation participates in peripheral T-cell activation and programmed cell death in vivo.
abstract: T-cell antigen receptor (TCR), which is not itself a protein tyrosine kinase (PTK), is thought to be associated with at least two SRC-like PTKs, P59fyn and ZAP-70. Activation of these PTKs is required for T-cell signal transduction. The aim of the present study was to determine the roles of PTKs in peripheral T-cell activation, induced by in vivo bacterial superantigen administration. We demonstrated that in vivo staphylococcal enterotoxin B (SEB) administration induced an enhanced tyrosine phosphorylation in peripheral spleen T cells undergoing a programmed cell death. In vitro immunecomplex kinase assay using antibody against P59fyn showed increased fyn kinase activity in SEB-stimulated spleen T cells. We examined the effect of PTK-specific inhibitors on DNA fragmentation and programmed cell death of V beta 8 positive T cells following in vitro culture of SEB-primed spleen T cells. Our results indicated that pretreatment of SEB-activated T cells with PTK inhibitors reduced DNA fragmentation and programmed cell death of V beta 8 positive T cells. These findings suggest that PTK plays an important role in activation and apoptosis of peripheral T cells induced by in vivo SEB administration.
authors.affiliation: First Department of Internal Medicine, Nagasaki University School of Medicine, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Migita
authors.forename: K
authors.initials: K
authors.lastname: Eguchi
authors.forename: Y
authors.initials: Y
authors.lastname: Kawabe
authors.forename: S
authors.initials: S
authors.lastname: Nagataki
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000276:immunology*; D004768:Enterotoxins / Q000276:immunology; D015151:Immunoblotting; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051076:Proto-Oncogene Proteins c-fyn; D013154:Spleen / Q000276:immunology; D018089:Superantigens / Q000276:immunology; D013601:T-Lymphocytes / Q000201:enzymology / Q000276:immunology*
chemical_list: D004768:Enterotoxins; D011518:Proto-Oncogene Proteins; D018089:Superantigens; C031818:enterotoxin B, staphylococcal; D011505:Protein-Tyrosine Kinases; C494960:Fyn protein, mouse; D051076:Proto-Oncogene Proteins c-fyn