title: Biodistribution of 131I-labeled anti-CK8 monoclonal antibody in HNSCC in xenotransplanted SCID mice.
abstract: BACKGROUND
  A new promising approach to improve the outcome of head and neck squamous cell carcinoma (HNSCC) is the application of radio-labeled antibodies directed against tumor-associated antigens. Cytokeratin 8 (CK8), an intermediate filament forming protein, is shown to be de novo expressed in dysplastic lesions as well as in HNSCC. Therefore like the epithelial cell adhesion molecule CK8 seems to be a suitable anchor molecule for targeted radioimmunotherapy (RIT). The aim of this study was to investigate the biodistribution of a radio-labeled Cytokeratin 8-specific monoclonal antibody (mAb) in a SCID (severe combined immunodeficiency disease) mouse model.
  
  
  METHODS
  The mAb against CK8 was labeled with (131)I and biodistribution was tested in established HNSCC xenografts in SCID mice. The biodistribution of the mAb in the tumor and different organs was determined with a gamma counter and was calculated as % injected dose/gram tissue.
  
  
  RESULTS
  Initially, after systemic administration of (131)I-anti CK8 monoclonal antibody high activity was seen in all the organs. Over time the general activity decreased, whereas activity accumulated in the tumor. This activity decayed compared to the other tissues with a two- to threefold prolonged radioactive half-life.
  
  
  CONCLUSIONS
  Specific antibody-antigen-binding is probably responsible for the prolonged radioactive half-life in the tumor and the resulting cumulative activity due to enrichment of the (131)I-anti CK8 mAb, so that Cytokeratin 8 seems to be a suitable anchor molecule for radioimmunotherapy in HNSCC.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Dachau Medical Center, Krankenhausstrasse 15, 85221 Dachau, Germany. Michaela.Andratschke@amperkliniken.de
authors.forename: Michaela
authors.initials: M
authors.lastname: Andratschke
authors.forename: Christian W
authors.initials: CW
authors.lastname: Luebbers
authors.forename: Veronika
authors.initials: V
authors.lastname: Johannson
authors.forename: Baerbel
authors.initials: B
authors.lastname: Schmitt
authors.forename: Brigitte
authors.initials: B
authors.lastname: Mack
authors.forename: Reinhard
authors.initials: R
authors.lastname: Zeidler
authors.forename: Stephan
authors.initials: S
authors.lastname: Lang
authors.forename: Barbara
authors.initials: B
authors.lastname: Wollenberg
authors.forename: Franz Josef
authors.initials: FJ
authors.lastname: Gildehaus
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D000951:Antigens, Neoplasm / Q000276:immunology; D002294:Carcinoma, Squamous Cell / Q000097:blood / Q000276:immunology / Q000378:metabolism*; D006258:Head and Neck Neoplasms / Q000097:blood / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D007275:Injections, Intravenous; D007457:Iodine Radioisotopes / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D007553:Isotope Labeling; D053533:Keratin-8 / Q000276:immunology*; D020714:Maximum Tolerated Dose; D051379:Mice; D016513:Mice, SCID; D009928:Organ Specificity; D000077195:Squamous Cell Carcinoma of Head and Neck; D014018:Tissue Distribution; D014183:Transplantation, Heterologous; D023041:Xenograft Model Antitumor Assays
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D007457:Iodine Radioisotopes; D053533:Keratin-8