title: The costimulation-regulated duration of PKB activation controls T cell longevity.
abstract: A brief antigenic stimulus can promote T cell proliferation, but the duration and nature of intracellular signals required for survival are unclear. Here we show that in the absence of OX40 costimulation, antigen-activated CD4+ cells are short-lived because the activity of protein kinase B (PKB; also known as Akt) is not maintained over time. Activated T cells that express a dominant-negative variant of PKB also undergo apoptosis, reproducing the OX40-deficient phenotype. In contrast, an active form of PKB prevents downregulation of antiapoptotic proteins in OX40-deficient T cells, rescues antigen-induced cell survival in vivo, and controls inflammation in recall responses. Thus, sustained and periodic PKB signaling has an integral role in regulating T cell longevity.
authors.affiliation: Division of Molecular Immunology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121, USA.
authors.forename: Jianxun
authors.initials: J
authors.lastname: Song
authors.forename: Shahram
authors.initials: S
authors.lastname: Salek-Ardakani
authors.forename: Paul R
authors.initials: PR
authors.lastname: Rogers
authors.forename: Mary
authors.initials: M
authors.lastname: Cheng
authors.forename: Luk
authors.initials: L
authors.lastname: Van Parijs
authors.forename: Michael
authors.initials: M
authors.lastname: Croft
mesh_terms: D000818:Animals; D017209:Apoptosis; D002455:Cell Division; D002470:Cell Survival; D007249:Inflammation / Q000201:enzymology / Q000276:immunology; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D011948:Receptors, Antigen, T-Cell / Q000235:genetics; D053262:Receptors, OX40; D018124:Receptors, Tumor Necrosis Factor / Q000172:deficiency / Q000235:genetics; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000166:cytology / Q000201:enzymology* / Q000276:immunology*
chemical_list: D011518:Proto-Oncogene Proteins; D011948:Receptors, Antigen, T-Cell; D053262:Receptors, OX40; D018124:Receptors, Tumor Necrosis Factor; C505717:Tnfrsf4 protein, mouse; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt