title: Inhibitory role of IFN-gamma-inducible lysosomal thiol reductase in T cell activation.
abstract: IFN-gamma-inducible lysosomal thiol reductase (GILT) is a unique thiol reductase with optimal enzymatic activity at low pH. GILT plays a crucial role in unfolding the antigenic proteins in preparation for their proteolytic cleavage and presentation of resulting peptides by MHC class II. In this study, we demonstrate that GILT is expressed in T lymphocytes and that it has an APC-nonrelated role in the regulation of T cell activation. Surprisingly, comparison of wild-type and GILT-deficient T cell activation in vitro revealed stronger responsiveness in the absence of GILT. The effect of GILT in reducing the proliferative and cytotoxic responses was endogenous to T cells and resulted from decreased sensitivity at the individual cell level. Therefore, a molecule with primarily lysosomal localization suppresses T cell activation, a process characterized by signal transmission from plasma membrane to cytoplasm and nucleus.
authors.affiliation: Center for Cancer and Immunology Research, Children's Research Institute, Children's National Medical Center, Washington, DC 20010, USA.
authors.forename: Igor
authors.initials: I
authors.lastname: Barjaktarević
authors.forename: Ayman
authors.initials: A
authors.lastname: Rahman
authors.forename: Sasa
authors.initials: S
authors.lastname: Radoja
authors.forename: Branka
authors.initials: B
authors.lastname: Bogunović
authors.forename: Alison
authors.initials: A
authors.lastname: Vollmer
authors.forename: Stanislav
authors.initials: S
authors.lastname: Vukmanović
authors.forename: Maja
authors.initials: M
authors.lastname: Marić
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism; D015153:Blotting, Western; D017252:CD3 Complex / Q000378:metabolism; D049109:Cell Proliferation; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D037181:Lectins, C-Type; D008213:Lymphocyte Activation / Q000276:immunology* / Q000502:physiology; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010088:Oxidoreductases / Q000378:metabolism*; D050862:Oxidoreductases Acting on Sulfur Group Donors; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D000099192:CD69 Antigens
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D037181:Lectins, C-Type; D010088:Oxidoreductases; D050862:Oxidoreductases Acting on Sulfur Group Donors; D000099192:CD69 Antigens; C483811:Ifi30 protein, mouse