title: Activated human CD4+ T cells express transporters for both cysteine and cystine.
abstract: Because naïve T cells are unable to import cystine due to the absence of cystine transporters, it has been suggested that T cell activation is dependent on cysteine generated by antigen presenting cells. The aim of this study was to determine at which phases during T cell activation exogenous cystine/cysteine is required and how T cells meet this requirement. We found that early activation of T cells is independent of exogenous cystine/cysteine, whereas T cell proliferation is strictly dependent of uptake of exogenous cystine/cysteine. Naïve T cells express no or very low levels of both cystine and cysteine transporters. However, we found that these transporters become strongly up-regulated during T cell activation and provide activated T cells with the required amount of cystine/cysteine needed for T cell proliferation. Thus, T cells are equipped with mechanisms that allow T cell activation and proliferation independently of cysteine generated by antigen presenting cells.
authors.affiliation: Department of International Health, Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3 , Copenhagen DK-2200,  Denmark.
authors.forename: Trine Bøegh
authors.initials: TB
authors.lastname: Levring
authors.forename: Ann Kathrine
authors.initials: AK
authors.lastname: Hansen
authors.forename: Bodil Lisbeth
authors.initials: BL
authors.lastname: Nielsen
authors.forename: Martin
authors.initials: M
authors.lastname: Kongsbak
authors.forename: Marina Rode
authors.initials: MR
authors.lastname: von Essen
authors.forename: Anders
authors.initials: A
authors.lastname: Woetmann
authors.forename: Niels
authors.initials: N
authors.lastname: Odum
authors.forename: Charlotte Menné
authors.initials: CM
authors.lastname: Bonefeld
authors.forename: Carsten
authors.initials: C
authors.lastname: Geisler
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D002478:Cells, Cultured; D003545:Cysteine / Q000378:metabolism*; D003553:Cystine / Q000378:metabolism*; D006801:Humans; D008213:Lymphocyte Activation; D026901:Membrane Transport Proteins / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D015854:Up-Regulation
chemical_list: D026901:Membrane Transport Proteins; D003553:Cystine; D003545:Cysteine