title: CD99 activates T cells via a costimulatory function that promotes raft association of TCR complex and tyrosine phosphorylation of TCR zeta.
abstract: We investigated the co-stimulatory role of a cell-surface protein, CD99. Co-ligation of CD99 and suboptimal CD3 induced T-cell activation to a level comparable to that obtained with optimal CD3 or CD3+CD28. We also noted concomitant enhancement of the earliest T-cell receptor (TCR) signaling events. In addition, co-ligation of CD99 and CD3 led to translocation of TCR complexes into the lipid raft, without concomitant migration of CD99 to the raft, and consequent enhancement of TCR zeta-mediated signal 1. These data demonstrate the unique properties of CD99 co-stimulation that distinguish this molecule from CD28 and other raft-resident co-stimulatory factors.
authors.affiliation: Department of Pathology, Hallym University College of Medicine, Chuncheon 200-702, Korea.
authors.forename: Kwon Ik
authors.initials: KI
authors.lastname: Oh
authors.forename: Byoung Kwon
authors.initials: BK
authors.lastname: Kim
authors.forename: Young Larn
authors.initials: YL
authors.lastname: Ban
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Choi
authors.forename: Kyeong Cheon
authors.initials: KC
authors.lastname: Jung
authors.forename: Im-Soon
authors.initials: IS
authors.lastname: Lee
authors.forename: Seong Hoe
authors.initials: SH
authors.lastname: Park
mesh_terms: D000071443:12E7 Antigen; D015703:Antigens, CD / Q000276:immunology*; D017252:CD3 Complex / Q000276:immunology; D015815:Cell Adhesion Molecules / Q000276:immunology*; D015536:Down-Regulation; D006801:Humans; D019169:Jurkat Cells; D008213:Lymphocyte Activation / Q000276:immunology*; D021962:Membrane Microdomains / Q000276:immunology*; D008565:Membrane Proteins / Q000276:immunology*; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism*; D021381:Protein Transport; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000071443:12E7 Antigen; D015703:Antigens, CD; D017252:CD3 Complex; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules; D008565:Membrane Proteins; D011948:Receptors, Antigen, T-Cell; C054979:antigen T cell receptor, zeta chain; D019000:Phosphotyrosine