Identification of a carcinoembryonic antigen binding protein on monocytes

Biochem Biophys Res Commun. 2003 Nov 14;311(2):319-23. doi: 10.1016/j.bbrc.2003.09.213.


Tumor-associated monocyte/macrophage cells are important stromal components involved in tumor development. A protein on human monocyte is identified that binds to carcinoembryonic antigen (CEA), a glycoprotein overexpressed in colon tumors. This implicates a role for this protein in CEA processing and establishes a link between monocytes and colon tumor cells. In vitro uptake of 125I-labeled CEA with isolated monocytes showed time and temperature dependence. The binding of 125I-CEA was specific and saturable as it could be inhibited by an excess of unlabeled CEA. To identify the binding protein on monocyte, we used a radiolabeled photoactivable heterobifunctional crosslinking agent and demonstrated that CEA reacts with a 115kDa protein as determined by SDS-polyacrylamide gel electrophoresis and autoradiography. Treatment of human monocytes in vitro with CEA resulted in a several fold increase in the production of proinflammatory cytokines TNF-alpha, IL-1 beta, and IL-6 compared to untreated controls. Binding of CEA to the monocyte protein may have implications in colon tumorigenesis.

Publication types

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

MeSH terms

  • Carcinoembryonic Antigen / chemistry*
  • Carcinoembryonic Antigen / immunology
  • Carcinoembryonic Antigen / metabolism*
  • Carrier Proteins / chemistry*
  • Carrier Proteins / immunology
  • Carrier Proteins / metabolism*
  • Cells, Cultured
  • Cytokines / biosynthesis*
  • Cytokines / immunology
  • Humans
  • Molecular Weight
  • Monocytes / chemistry*
  • Monocytes / immunology
  • Monocytes / metabolism*
  • Protein Binding
  • Receptors, Cell Surface*


  • Carcinoembryonic Antigen
  • Carrier Proteins
  • Cytokines
  • Receptors, Cell Surface
  • carcinoembryonic antigen binding protein, human