Structural, functional, and tissue distribution analysis of human transferrin receptor-2 by murine monoclonal antibodies and a polyclonal antiserum

Silvia Deaglio, Andrea Capobianco, Angelita Calì, Francesca Bellora, Federica Alberti, Luisella Righi, Anna Sapino, Clara Camaschella, Fabio Malavasi

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Abstract

Human transferrin receptor-2 (TFR-2) is a protein highly homologous to TFR-1/CD71 and is endowed with the ability to bind transferrin (TF) with low affinity. High levels of TFR-2 mRNA were found in the liver and in erythroid precursors. Mutations affecting the TFR-2 gene led to hemochromatosis type 3, a form of inherited iron overload. Several issues on distribution and function of the receptor were answered by raising a panel of 9 monoclonal antibodies specific for TFR-2 by immunizing mice with murine fibroblasts transfected with the human TFR-2 cDNA. A polyclonal antiserum was also produced in mice immunized with 3 peptides derived from the TFR-2 sequence, exploiting an innovative technique. The specificity of all the reagents produced was confirmed by reactivity with TFR-2+ target cells and simultaneous negativity with TFR-1+ cells. Western blot analyses showed a dominant chain of approximately 90 kDa in TFR-2 transfectants and HepG2 cell line. Analysis of distribution in normal tissues and in representative cell lines revealed that TFR-2 displays a restricted expression pattern - it is present at high levels in hepatocytes and in the epithelial cells of the small intestine, including the duodenal crypts. Exposure of human TFR-2+ cells to TF-bound iron is followed by a significant up-regulation and relocalization of membrane TFR-2. The tissue distribution pattern, the behavior following exposure to iron-loaded TF, and the features of the disease resulting from TFR-2 inactivation support the hypothesis that TFR-2 contributes to body iron sensing.

Original languageEnglish
Pages (from-to)3782-3789
Number of pages8
JournalBlood
Volume100
Issue number10
DOIs
Publication statusPublished - Nov 15 2002

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ASJC Scopus subject areas

  • Hematology

Cite this

Deaglio, S., Capobianco, A., Calì, A., Bellora, F., Alberti, F., Righi, L., Sapino, A., Camaschella, C., & Malavasi, F. (2002). Structural, functional, and tissue distribution analysis of human transferrin receptor-2 by murine monoclonal antibodies and a polyclonal antiserum. Blood, 100(10), 3782-3789. https://doi.org/10.1182/blood-2002-01-0076