The bispecific immunoligand ULBP2-aCEA redirects natural killer cells to tumor cells and reveals potent anti-tumor activity against colon carcinoma

Int J Cancer. 2014 Jun 15;134(12):2829-40. doi: 10.1002/ijc.28609. Epub 2013 Nov 29.


NKG2D, an activating receptor expressed on NK cells and T cells, is critically involved in tumor immunosurveillance. In this study, we explored the potential therapeutic utility of the NKG2D ligand ULBP2 for the treatment of colon carcinoma. To this end we designed a fusion protein consisting of human ULBP2 and an antibody-derived single chain targeting the tumor carcinoembryonic antigen (CEA). The bispecific recombinant fusion protein re-directed NK cells towards malignant cells by binding to both, tumor cells and NK cells, and triggered NK cell-mediated target cell killing in vitro. Moreover, tumor growth was significantly delayed in a syngeneic colon carcinoma mouse model in response to immunoligand treatment. The anti-tumor activity could be attributed to the stimulation of immune cells with an elevated expression of the activation marker CD69 on NK, T and NKT cells and the infiltration of CD45+ immune cells into the solid tumor. In summary, it was demonstrated that immunoligands provide specific tumor targeting by NK cells and exert anti-tumor activity in vitro and in vivo. This technology represents a novel immunotherapeutic strategy for solid tumors with the potential to be further developed for clinical applications.

Keywords: NK cells; NKG2D; colon carcinoma; immunotherapy.

MeSH terms

  • Adoptive Transfer
  • Animals
  • Antigens, CD / metabolism
  • Antigens, Differentiation, T-Lymphocyte / metabolism
  • Carcinoembryonic Antigen / genetics
  • Carcinoembryonic Antigen / immunology*
  • Cell Line, Tumor
  • Colonic Neoplasms / immunology*
  • Colonic Neoplasms / therapy*
  • Disease Models, Animal
  • GPI-Linked Proteins / therapeutic use
  • HEK293 Cells
  • Humans
  • Immunotherapy, Adoptive
  • Intercellular Signaling Peptides and Proteins / therapeutic use*
  • Killer Cells, Natural / immunology
  • Killer Cells, Natural / transplantation
  • Lectins, C-Type / metabolism
  • Leukocyte Common Antigens / metabolism
  • Mice
  • Mice, Inbred C57BL
  • NK Cell Lectin-Like Receptor Subfamily K / immunology*
  • Natural Killer T-Cells / immunology*
  • Recombinant Fusion Proteins / therapeutic use
  • Single-Chain Antibodies / genetics
  • Single-Chain Antibodies / immunology


  • Antigens, CD
  • Antigens, Differentiation, T-Lymphocyte
  • CD69 antigen
  • Carcinoembryonic Antigen
  • GPI-Linked Proteins
  • Intercellular Signaling Peptides and Proteins
  • KLRK1 protein, human
  • Lectins, C-Type
  • NK Cell Lectin-Like Receptor Subfamily K
  • Recombinant Fusion Proteins
  • Single-Chain Antibodies
  • ULBP2 protein, human
  • Leukocyte Common Antigens
  • PTPRC protein, human