title: Inhibition of T cell activation and autoimmune diabetes using a B cell surface-linked CTLA-4 agonist.
abstract: CTL-associated antigen 4 (CTLA-4) engagement negatively regulates T cell activation and function and promotes immune tolerance. However, it has been difficult to explore the biology of selective engagement of CTLA-4 in vivo because CTLA-4 shares its ligands, B7-1 and B7-2, with CD28. To address this issue, we developed a Tg mouse expressing a single-chain, membrane-bound anti-CTLA-4 Ab (scFv) on B cells. B and T cells developed normally and exhibited normal phenotype in the steady state and after activation in these mice. However, B cells from scFv Tg+ mice (scalphaCTLA4+) prevented T cell proliferation and cytokine production in mixed lymphocyte reactions. Additionally, mice treated with scalphaCTLA4+ B cells had decreased T cell-dependent B cell Ab production and class switching in vivo after antigen challenge. Furthermore, expression of this CTLA-4 agonist protected NOD mice from spontaneous autoimmune diabetes. Finally, this disease prevention occurred in Treg-deficient NOD.B7-1/B7-2 double-knockout mice, suggesting that the effect of the CTLA-4 agonist directly attenuates autoreactive T cell activation, not Treg activation. Together, results from this study demonstrate that selective ligation of CTLA-4 attenuates in vivo T cell responses, prevents development of autoimmunity, and represents a novel immunotherapeutic approach for the induction and maintenance of peripheral tolerance.
authors.affiliation: UCSF Diabetes Center, Department of Medicine, UCSF, San Francisco, California 94143, and Department of Internal Medicine, Division of Nephrology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Brian T
authors.initials: BT
authors.lastname: Fife
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Griffin
authors.forename: Abul K
authors.initials: AK
authors.lastname: Abbas
authors.forename: Richard M
authors.initials: RM
authors.lastname: Locksley
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Bluestone
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000276:immunology* / Q000502:physiology; D001402:B-Lymphocytes / Q000276:immunology*; D018122:B7-1 Antigen / Q000235:genetics / Q000276:immunology; D051940:B7-2 Antigen / Q000235:genetics / Q000276:immunology; D060908:CTLA-4 Antigen; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology* / Q000517:prevention & control; D008213:Lymphocyte Activation; D051379:Mice; D016688:Mice, Inbred NOD; D018345:Mice, Knockout; D008822:Mice, Transgenic; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D060908:CTLA-4 Antigen; C556707:Ctla4 protein, mouse; D011948:Receptors, Antigen, T-Cell