title: Murine T cells expressing high activity of prolyl endopeptidase are susceptible to activation-induced cell death.
abstract: Prolyl endopeptidase (PEP) is widely distributed and thought to play an important role in the degradation of peptide hormones and neuropeptides, but its biological role is totally unknown. In this study, we examined PEP activity in subpopulations of murine T cells and found that PEP activity was significantly higher in immature thymocytes than in mature thymocytes or in peripheral T cells. Stimulation of murine peripheral T cells time-dependently increased PEP activity. Although murine T cell hybridomas exhibited high PEP activity, the PEP activity was fully inhibited by treatment with PEP inhibitor. The pretreated T cells were found to be resistant to activation-induced cell death (AICD). Similar results were obtained in murine thymocytes as well as in activated peripheral T cells. PEP activity in T cell hybridomas remained unchanged during AICD. These results suggest that T cells expressing high PEP activity are susceptible to ACID.
authors.affiliation: Department of Bacterial and Blood Products, National Institute of Infectious Diseases, 1-23-1, Toyama, Shinjuku-ku, 162-8640, Tokyo, Japan. odaka@nih.go.jp
authors.forename: Chikako
authors.initials: C
authors.lastname: Odaka
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Mizuochi
authors.forename: Takuo
authors.initials: T
authors.lastname: Shirasawa
authors.forename: Philippe
authors.initials: P
authors.lastname: Morain
authors.forename: Fredéric
authors.initials: F
authors.lastname: Checler
mesh_terms: D000818:Animals; D017209:Apoptosis; D005260:Female; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D000085822:Prolyl Oligopeptidases; D012697:Serine Endopeptidases / Q000096:biosynthesis*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D013601:T-Lymphocytes / Q000201:enzymology*; D013950:Thymus Gland / Q000166:cytology / Q000201:enzymology
chemical_list: D015842:Serine Proteinase Inhibitors; D012697:Serine Endopeptidases; D000085822:Prolyl Oligopeptidases