title: Blockade of T cell activation using a surface-linked single-chain antibody to CTLA-4 (CD152).
abstract: CTLA-4 (CD152) engagement can down-regulate T cell activation and promote the induction of immune tolerance. However, the strategy of attenuating T cell activation by engaging CTLA-4 has been limited by sharing of its natural ligands with the costimulatory protein CD28. In the present study, a CTLA-4-specific single-chain Ab (scFv) was developed and expressed on the cell surface to promote selective engagement of this regulatory molecule. Transfectants expressing anti-CTLA-4 scFv at their surface bound soluble CTLA-4 but not soluble CD28. Coexpression of anti-CTLA-4 scFv with anti-CD3epsilon and anti-CD28 scFvs on artificial APCs reduced the proliferation and IL-2 production by resting and preactivated bulk T cells as well as CD4+ and CD8+ T cell subsets. Importantly, expression of anti-CTLA-4 scFv on the same cell surface as the TCR ligand was essential for the inhibitory effects of CTLA-4-specific ligation. CTLA-4-mediated inhibition of tyrosine phosphorylation of components of the proximal TCR signaling apparatus was similarly dependent on coexpression of TCR and CTLA-4 ligands on the same surface. These findings support a predominant role for CTLA-4 function in the modification of the proximal TCR signal. Using T cells from DO11.10 and 2C TCR transgenic mice, negative regulatory effects of selective CTLA-4 ligation were also demonstrated during the stimulation of Ag-specific CD4+ and CD8+ T cells by MHC/peptide complexes. Together these studies demonstrate that selective ligation of CTLA-4 using a membrane-bound scFv results in attenuated T cell responses only when coengaged with the TCR during T cell/APC interaction and define an approach to harnessing the immunomodulatory potential of CTLA-4-specific ligation.
authors.affiliation: The Ben May Institute for Cancer Research and Department of Pathology and Committee on Immunology, University of Chicago, Chicago, IL 60637, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Griffin
authors.forename: D K
authors.initials: DK
authors.lastname: Hong
authors.forename: P O
authors.initials: PO
authors.lastname: Holman
authors.forename: K M
authors.initials: KM
authors.lastname: Lee
authors.forename: M J
authors.initials: MJ
authors.lastname: Whitters
authors.forename: S M
authors.initials: SM
authors.lastname: O'Herrin
authors.forename: F
authors.initials: F
authors.lastname: Fallarino
authors.forename: M
authors.initials: M
authors.lastname: Collins
authors.forename: D M
authors.initials: DM
authors.lastname: Segal
authors.forename: T F
authors.initials: TF
authors.lastname: Gajewski
authors.forename: D M
authors.initials: DM
authors.lastname: Kranz
authors.forename: J A
authors.initials: JA
authors.lastname: Bluestone
mesh_terms: D000069594:Abatacept; D000595:Amino Acid Sequence; D000818:Animals; D019138:Antibodies, Blocking / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D000918:Antibody Specificity / Q000235:genetics; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000276:immunology* / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D060908:CTLA-4 Antigen; D002460:Cell Line; D016207:Cytokines / Q000096:biosynthesis / Q000378:metabolism; D005260:Female; D006801:Humans; D018796:Immunoconjugates; D007135:Immunoglobulin Variable Region / Q000096:biosynthesis / Q000276:immunology* / Q000378:metabolism; D007399:Interphase / Q000235:genetics / Q000276:immunology; D008024:Ligands; D008213:Lymphocyte Activation / Q000235:genetics / Q000276:immunology*; D008285:Major Histocompatibility Complex / Q000235:genetics / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics / Q000276:immunology; D011947:Receptors, Antigen, B-Cell / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D019138:Antibodies, Blocking; D015703:Antigens, CD; D000943:Antigens, Differentiation; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; C556707:Ctla4 protein, mouse; D016207:Cytokines; D018796:Immunoconjugates; D007135:Immunoglobulin Variable Region; D008024:Ligands; D010455:Peptides; D011947:Receptors, Antigen, B-Cell; D011948:Receptors, Antigen, T-Cell; D000069594:Abatacept