title: Monovalent antibody scFv fragments selected to modulate T-cell activation by inhibition of CD86-CD28 interaction.
abstract: Beside the interaction of the antigen-presenting major histocompatibility complex with the T-cell receptor, a co-stimulatory signal is required for T-cell activation in an immune response. To reduce immune-mediated graft rejection in corneal transplantation, where topical application of drugs in ointments or eye-drops may be possible, we selected single-chain antibody fragments (scFv) with binding affinity to rat CD86 (B7.2) that inhibit the co-stimulatory signal. We produced the IgV-like domain of rat CD86 as a fusion protein in Escherichia coli by refolding from inclusion bodies. This protein was used as a target for phage display selection of scFv from HuCAL-1, a fully artificial human antibody library. Selected binding molecules were shown to specifically bind to rat CD86 and inhibit the interaction of CD86 with CD28 and CTLA4 (CD152) in flow cytometry experiments. In an assay for CD86-dependent co-stimulation, the selected scFv fragment successfully inhibited the proliferation of T-cells induced by CD86-expressing P815 cells.
authors.affiliation: Department of Biochemistry, University of Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland.
authors.forename: Reto
authors.initials: R
authors.lastname: Kolly
authors.forename: Michael A
authors.initials: MA
authors.lastname: Thiel
authors.forename: Thomas
authors.initials: T
authors.lastname: Herrmann
authors.forename: Andreas
authors.initials: A
authors.lastname: Plückthun
mesh_terms: D000818:Animals; D051940:B7-2 Antigen / Q000276:immunology / Q000378:metabolism*; D018106:CD28 Antigens / Q000276:immunology / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D007128:Immunoglobulin Fragments / Q000276:immunology*; D007135:Immunoglobulin Variable Region / Q000276:immunology*; D008213:Lymphocyte Activation; D034801:Mastocytoma / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D051379:Mice; D019151:Peptide Library; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology*; D014407:Tumor Cells, Cultured
chemical_list: D051940:B7-2 Antigen; D018106:CD28 Antigens; C497966:Cd86 protein, rat; D007128:Immunoglobulin Fragments; D007135:Immunoglobulin Variable Region; D019151:Peptide Library; D011993:Recombinant Fusion Proteins