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i-bodies, Human Single Domain Antibodies That Antagonize Chemokine Receptor CXCR4.

Griffiths K, Dolezal O, Cao B, Nilsson SK, See HB, Pfleger KDG, Roche M, Gorry PR, Pow A, Viduka K, Lim K, Lu BGC, Chang DHC, Murray-Rust T, Kvansakul M, Perugini MA, Dogovski C, Doerflinger M, Zhang Y, Parisi K, Casey JL, Nuttall SD, Foley M

  • Journal The Journal of biological chemistry

  • Published 01 Apr 2016

  • Volume 291

  • ISSUE 24

  • Pagination 12641-12657

  • DOI 10.1074/jbc.M116.721050


CXCR4 is a G protein-coupled receptor with excellent potential as a therapeutic target for a range of clinical conditions, including stem cell mobilization, cancer prognosis and treatment, fibrosis therapy, and HIV infection. We report here the development of a fully human single-domain antibody-like scaffold termed an "i-body," the engineering of which produces an i-body library possessing a long complementarity determining region binding loop, and the isolation and characterization of a panel of i-bodies with activity against human CXCR4. The CXCR4-specific i-bodies show antagonistic activity in a range of in vitro and in vivo assays, including inhibition of HIV infection, cell migration, and leukocyte recruitment but, importantly, not the mobilization of hematopoietic stem cells. Epitope mapping of the three CXCR4 i-bodies AM3-114, AM4-272, and AM3-523 revealed binding deep in the binding pocket of the receptor.