Lactoferrin binding by leukemia cell lines

Y. Yamada, T. Amagasaki, D. W. Jacobsen, Ralph Green

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

Monocytes and macrophages have receptors for the iron-binding protein lactoferrin. Lactoferrin acts as a potent inhibitor of granulocyte-macrophage colony stimulating factor production when it binds to these cells. Using a rosette assay and immunofluorescence, we have shown that cultured leukemia cells, including the human erythroid leukemia cell line K562, also have lactoferrin binding sites. The number of binding sites on K562 cells was estimated using soluble 59Fe-lactoferrin. Inhibition studies demonstrate that lactoferrin binding sites are distinct and unrelated to receptors for transferrin or the Fc portion of IgG, which are present on K562 cells. However, electrostatic forces may be important for lactoferrin binding, since other polycationic proteins (eg, protamine) inhibit lactoferrin binding. Prior treatment of K562 cells with trypsin nearly abolishes lactoferrin binding. However, these cells recover their ability to bind lactoferrin when trypsin is removed. Unlike transferrin receptors, the expression of lactoferrin binding sites is not regulated by cellular iron status. Cytosine arabinoside arrests the proliferation of K562 cells and simultaneously leads to a reduction in lactoferrin surface binding, suggesting that lactoferrin binding may be dependent on cell proliferation.

Original languageEnglish (US)
Pages (from-to)264-270
Number of pages7
JournalBlood
Volume70
Issue number1
StatePublished - 1987
Externally publishedYes

ASJC Scopus subject areas

  • Hematology

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    Yamada, Y., Amagasaki, T., Jacobsen, D. W., & Green, R. (1987). Lactoferrin binding by leukemia cell lines. Blood, 70(1), 264-270.