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Jens Christian Jensenius

Modified cytokeratins expressed on the surface of carcinoma cells undergo endocytosis upon binding of human monoclonal antibody and its recombinant Fab fragment

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

  • H J Ditzel
  • ,
  • U Garrigues
  • ,
  • C B Andersen
  • ,
  • M K Larsen, Denmark
  • H J Garrigues
  • ,
  • Anja Svejgaard
  • ,
  • I Hellström
  • ,
  • K E Hellström
  • ,
  • Jens Christian Jensenius
Previously, we have reported on successful imaging of colon, rectal, and pancreatic carcinomas in patients by using a radiolabeled all-human monoclonal antibody, COU-1, directed against modified cytokeratin. To further develop this antibody for use as an immunoconjugate, COU-1 was cloned by phage display selection and the human Fab fragment was expressed in bacteria. Analysis by confocal laser scanning microscopy demonstrated that COU-1 bound in a uniform punctate pattern to the surface of viable carcinoma cells stained at 4 degrees C, and binding increased significantly when cells were cultured on fibronectin, laminin, or collagen IV. In the case of fibronectin, COU-1 staining was particularly enhanced at intercellular junctions. When carcinoma cells were cultured with COU-1 at 37 degrees C for 6 hr, the antibody was found in large perinuclear vesicles and the punctate surface staining was significantly reduced. Similar results were obtained using intact IgM COU-1 and the recombinant Fab fragment. Immunohistological studies indicated that COU-1, in contrast to murine monoclonal antibodies against normal cytokeratin 8 and 18, could differentiate between malignant and normal colon epithelia, and between colon cancer metastasis in the liver and surrounding normal hepatocytes. Within biopsies of malignant tissue, COU-1 exhibited membrane-associated staining of proliferating cells, while resting cells had a filamentous pattern. Thus, modified cytokeratin at the surface of carcinoma cells may represent a new target for immunoconjugates and may explain the promising results of the phase I/II clinical study.
Original languageEnglish
JournalProceedings of the National Academy of Sciences of the United States of America
Volume94
Issue15
Pages (from-to)8110-5
Number of pages6
ISSN0027-8424
Publication statusPublished - 1997

    Research areas

  • Amino Acid Sequence, Antibodies, Monoclonal, Bacteriophages, Binding Sites, Antibody, Cell Line, Colon, Colonic Neoplasms, Endocytosis, Humans, Immunoglobulin Fab Fragments, Intestinal Mucosa, Keratins, Molecular Sequence Data, Recombinant Proteins

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