title: Humanization of an anti-CCR4 antibody that kills cutaneous T-cell lymphoma cells and abrogates suppression by T-regulatory cells.
abstract: Cutaneous T-cell lymphoma (CTCL) is a heterogeneous group of neoplastic disorders characterized by clonally derived and skin-homing malignant T cells that express high level of chemokine receptor CCR4, which is associated with their skin-homing capacity. CCR4 is also highly expressed on T-regulatory cells (Tregs) that can migrate to several different types of chemotactic ligand CCL17- and CCL22-secreting tumors to facilitate tumor cell evasion from immune surveillance. Thus, its high-level expression on CTCL cells and Tregs makes CCR4 a potential ideal target for antibody-based immunotherapy for CTCL and other types of solid tumors. Here, we conducted humanization and affinity optimization of a murine anti-CCR4 monoclonal antibody (mAb), mAb1567, that recognizes both the N-terminal and extracellular domains of CCR4 with high affinity and inhibits chemotaxis of CCR4(+) CTCL cells. In a mouse CTCL tumor model, mAb1567 exhibited a potent antitumor effect and in vitro mechanistic studies showed that both complement-dependent cytotoxicity (CDC) and neutrophil-mediated antibody-dependent cellular cytotoxicity (ADCC) likely mediated this effect. mAb1567 also exerts human NK cell-mediated ADCC activity in vitro. Moreover, mAb1567 also effectively inhibits chemotaxis of CD4(+)CD25(high) Tregs via CCL22 and abrogates Treg suppression activity in vitro. An affinity-optimized variant of humanized mAb1567, mAb2-3, was selected for further preclinical development based on its higher binding affinity and more potent ADCC and CDC activities. Taken together, this high-affinity humanized mAb2-3 with potent antitumor effect and a broad range of mechanisms of action may provide a novel immunotherapy for CTCL and other solid tumors.
authors.affiliation: Dana-Farber Cancer Institute-Harvard Medical School, 450 Brookline Ave., Boston, MA 02215, USA. wayne_marasco@dfci.harvard.edu
authors.forename: De-Kuan
authors.initials: DK
authors.lastname: Chang
authors.forename: Jianhua
authors.initials: J
authors.lastname: Sui
authors.forename: Shusheng
authors.initials: S
authors.lastname: Geng
authors.forename: Asli
authors.initials: A
authors.lastname: Muvaffak
authors.forename: Mei
authors.initials: M
authors.lastname: Bai
authors.forename: Robert C
authors.initials: RC
authors.lastname: Fuhlbrigge
authors.forename: Agnes
authors.initials: A
authors.lastname: Lo
authors.forename: Anuradha
authors.initials: A
authors.lastname: Yammanuru
authors.forename: Luke
authors.initials: L
authors.lastname: Hubbard
authors.forename: Jared
authors.initials: J
authors.lastname: Sheehan
authors.forename: James J
authors.initials: JJ
authors.lastname: Campbell
authors.forename: Quan
authors.initials: Q
authors.lastname: Zhu
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Kupper
authors.forename: Wayne A
authors.initials: WA
authors.lastname: Marasco
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology* / Q000627:therapeutic use*; D000920:Antibody-Dependent Cell Cytotoxicity / Q000187:drug effects*; D045744:Cell Line, Tumor; D002633:Chemotaxis / Q000187:drug effects; D003001:Cloning, Molecular; D003165:Complement System Proteins / Q000276:immunology; D006801:Humans; D016410:Lymphoma, T-Cell, Cutaneous / Q000188:drug therapy* / Q000473:pathology*; D051379:Mice; D016513:Mice, SCID; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects / Q000276:immunology; D011485:Protein Binding / Q000187:drug effects; D054398:Receptors, CCR4 / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D050505:Mutant Proteins; D054398:Receptors, CCR4; D003165:Complement System Proteins