Antibody dependent cellular phagocytosis (ADCP) and antibody dependent cellular cytotoxicity (ADCC) of breast cancer cells mediated by bispecific antibody, MDX-210

Breast Cancer Res Treat. 1999 Feb;53(3):199-207. doi: 10.1023/a:1006145507567.


Background: MDX-210 is a bispecific antibody (BsAb) with specificity for both the proto-oncogene product of HER-2/neu (c-erbB-2) and FcgammaRI (CD64). HER-2/neu is overexpressed in malignant tissue of approximately 30% of patients with breast cancer, and FcgammaRI is expressed on human monocytes, macrophages, and IFN-gamma activated granulocytes. We investigated phagocytosis and cytolysis of cultured human breast cancer cells by human monocyte-derived macrophages (MDM) mediated by BsAb MDX-210, its partially humanized derivative (MDX-H210), and its parent MoAb 520C9 (anti-HER-2/neu) under various conditions.

Materials and methods: Purified monocytes were cultured with GM-CSF, M-CSF, or no cytokine for five or six days. Antibody dependent cellular phagocytosis (ADCP) and cytolysis (ADCC) assays were performed with the MDM and HER-2/neu positive target cells (SK-BR-3). ADCP was measured by two-color fluorescence flow cytometry using PKH2 (green fluorescent dye) and phycoerythrin-conjugated (red) monoclonal antibodies (MoAb) against human CD14 and CD11b. ADCC was measured with a non-radioactive LDH detection kit.

Results: Both BsAb MDX-210 (via FcgammaRI) and MoAb 520C9 (mouse IgG1, via FcgammaRII) mediated similar levels of ADCP and ADCC. ADCP mediated by BsAb MDX-H210 was identical to that mediated by BsAb MDX-210. Confocal microscopy demonstrated that dual-labeled cells represented true phagocytosis. Both ADCP and ADCC were higher when MDM were pre-incubated with GM-CSF than when incubated with M-CSF.

Conclusions: BsAb MDX-210 is as active in vitro as the parent MoAb 520C9 in inducing both phagocytosis and cytolysis of MDM. MDX-210 and its partially humanized derivative, MDX-H210, mediated similar levels of ADCP. GM-CSF appears to superior to M-CSF in inducing MDM-mediated ADCC and ADCP. These studies support the ongoing clinical investigations of BsAb MDX-210 and its partially humanized derivative.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antibodies, Bispecific / metabolism
  • Antibodies, Bispecific / pharmacology*
  • Antibodies, Monoclonal / metabolism
  • Antibodies, Monoclonal / pharmacology*
  • Antibody Specificity
  • Antibody-Dependent Cell Cytotoxicity / drug effects*
  • Antibody-Dependent Cell Cytotoxicity / immunology
  • Breast Neoplasms / immunology*
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology
  • Carcinoma / immunology*
  • Carcinoma / metabolism
  • Carcinoma / pathology
  • Cytokines / pharmacology
  • Cytotoxicity Tests, Immunologic
  • Dose-Response Relationship, Drug
  • Epitopes
  • Female
  • Flow Cytometry
  • Humans
  • Macrophages / cytology
  • Macrophages / drug effects
  • Mice
  • Microscopy, Confocal
  • Phagocytosis / drug effects*
  • Phagocytosis / immunology
  • Receptor, ErbB-2 / immunology*
  • Receptors, IgG / immunology*
  • Tumor Cells, Cultured
  • U937 Cells


  • Antibodies, Bispecific
  • Antibodies, Monoclonal
  • Cytokines
  • Epitopes
  • Receptors, IgG
  • Receptor, ErbB-2