Transferrin-Independent Iron Uptake Supports B Lymphocyte Growth

• Published in: Blood 1991-09, Vol.78 (6), p.1526-1531
• Main Authors: Seligman, Paul A., Kovar, Jan, Schleicher, Rhoda B., Gelfand, Erwin W.
• Format: Article
• Language: English
• Subjects: B-Lymphocytes - metabolism; B-Lymphocytes - pathology; Biological and medical sciences; Burkitt Lymphoma - metabolism; Calcium - pharmacology; Cell Division; Ferritins - metabolism; Ferrous Compounds - metabolism; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Immunobiology; Iron - metabolism; Receptors, Transferrin - metabolism; Transferrin - biosynthesis; Tumor Cells, Cultured - metabolism
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V78.6.1526.1526

Raji, a malignant B-lymphocyte cell line containing Epstein-Barr virus genomic elements, has been conditioned to proliferate optimally in transferrin (Tf)-free medium containing a very low concentration of an iron salt. We provide evidence that an Tf-independent iron uptake system is physiologically important for maintaining the growth of these cells. The data show that Raji cells take up iron from iron salts using a relatively high-capacity, low-affinity, temperature- and calcium-dependent uptake system. The apparent capacity of this system increases when: (1) cells are cultured in Tf-free medium containing high concentrations of iron salt as op-posed to medium containing Tf; and (2) when the iron salt concentration of Tf-free medium is lowered to about 1.6 μmol/L. Cellular iron uptake also increases when a maximum number of cells are in S and G2 and M cell phases of the cell cycle. The cells are sensitive to growth inhibition by the addition of deferoxamine. This evidence supports the hypothesis that certain malignant lymphocytes, under iron deplete conditions, fulfill an iron requirement for proliferation by an adaptation such as Tf-independent iron uptake. © 1991 by The American Society of Hematology.