Humanization of an anti-CCR4 antibody that kills cutaneous T-cell lymphoma cells and abrogates suppression by T-regulatory cells

Mol Cancer Ther. 2012 Nov;11(11):2451-61. doi: 10.1158/1535-7163.MCT-12-0278. Epub 2012 Aug 6.


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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies, Monoclonal / chemistry
  • Antibodies, Monoclonal / immunology
  • Antibodies, Monoclonal / pharmacology*
  • Antibodies, Monoclonal / therapeutic use*
  • Antibody-Dependent Cell Cytotoxicity / drug effects*
  • Cell Line, Tumor
  • Chemotaxis / drug effects
  • Cloning, Molecular
  • Complement System Proteins / immunology
  • Humans
  • Lymphoma, T-Cell, Cutaneous / drug therapy*
  • Lymphoma, T-Cell, Cutaneous / pathology*
  • Mice
  • Mice, SCID
  • Molecular Sequence Data
  • Mutant Proteins / chemistry
  • Mutant Proteins / metabolism
  • Neutrophils / drug effects
  • Neutrophils / immunology
  • Protein Binding / drug effects
  • Receptors, CCR4 / immunology*
  • T-Lymphocytes, Regulatory / drug effects
  • T-Lymphocytes, Regulatory / immunology*


  • Antibodies, Monoclonal
  • Mutant Proteins
  • Receptors, CCR4
  • Complement System Proteins