Lymphocyte lines under iron-depriving conditions: transferrin receptor expression related to various growth responses

The relation of expression of cell surface transferrin receptors to growth responses under defined iron-depriving conditions was studied in mouse B-cell line PLV-01, human T-cell line Jurkat, and human B-cell line Raji. Iron chelator deferoxamine at a concentration of 150 microM, which inhibited completely growth of the cell lines cultured in a serum-free transferrin-containing (5 micrograms/ml) medium, stimulated the surface transferrin receptor number to increase to 150-250% within a 24-h incubation period. The increased number (300%) of transferrin receptors on PLV-01 cells was associated with complete growth inhibition of these cells in counterpart serum-free transferrin-free medium. Only a slight increase in transferrin receptor number on Raji cells corresponded with unaffected growth of these cells in the transferrin-free medium. Jurkat cells increased the number of transferrin receptors to 150-200% and decreased the number of cells grown in the transferrin-free medium to about 60%. The data show that, under limited availability of iron, a significant increase of transferrin receptor expression on lymphoid cells was found only when the growth of the cells was inhibited. However, complete inhibition of growth achieved under different iron-depriving conditions is accompanied by different degrees of increase in transferrin receptor number.