title: Cutting edge: Regulation of CD8(+) T cell proliferation by 2B4/CD48 interactions.
abstract: The biological function of 2B4, a CD48-binding molecule expressed on T cells with an activation/memory phenotype, is not clear. In this report, we demonstrate that proliferation of CD8(+) T cells is regulated by 2B4. Proliferative responses of CD8(+) T cells were significantly reduced by anti-2B4 Ab. The effects were not potentiated by anti-CD48 Ab, suggesting that the observed responses were driven by 2B4/CD48 interactions. Surprisingly, the 2B4/CD48-dependent proliferative responses were also observed in the absence of APCs. This suggests that 2B4/CD48 interactions can occur directly between T cells. Furthermore, when activated 2B4(+)CD8(+) T cells were mixed with 2B4(-)CD8(+) TCR-transgenic T cells and specific peptide-loaded APC, the proliferation of the latter T cells was inhibited by anti-2B4 Ab. Taken together, this suggests that 2B4 on activated/memory T cells serves as a ligand for CD48, and by its ability to interact with CD48 provides costimulatory-like function for neighboring T cells.
authors.affiliation: Microbiology and Tumor Biology Center, Karolinska Institutet, Stockholm, Sweden.
authors.forename: T
authors.initials: T
authors.lastname: Kambayashi
authors.forename: E
authors.initials: E
authors.lastname: Assarsson
authors.forename: B J
authors.initials: BJ
authors.lastname: Chambers
authors.forename: H G
authors.initials: HG
authors.lastname: Ljunggren
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D000938:Antigen-Presenting Cells / Q000276:immunology; D000941:Antigens / Q000276:immunology; D015703:Antigens, CD / Q000276:immunology / Q000378:metabolism*; D000071178:CD48 Antigen; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D016207:Cytokines / Q000494:pharmacology; D005434:Flow Cytometry; D019672:Genes, T-Cell Receptor; D007156:Immunologic Memory; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D012333:RNA, Messenger / Q000096:biosynthesis; D011971:Receptors, Immunologic; D000071176:Signaling Lymphocytic Activation Molecule Family
chemical_list: D000906:Antibodies; D000941:Antigens; D015703:Antigens, CD; D000071178:CD48 Antigen; C490007:Cd244a protein, mouse; C000604066:Cd48 protein, mouse; D016207:Cytokines; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D000071176:Signaling Lymphocytic Activation Molecule Family