Structural features in carrageenan that interact with a heparin-binding hematopoietic growth factor and modulate its biological activity

The effects of carrageenans’ structural features on its interaction with granulocyte colony-stimulating factor (G-CSF) and on the growth and differentiation of a G-CSF dependent leukemia cell line (NFS-60) were studied. λ, ι, and κ carrageenans, with decreasing contents of sulfation, bound to G-CSF with binding constants of (6.2 ± 0.6) × 105 M−1, (7.4 ± 0.5) × 105 M−1 and (6.0 ± 0.4) × 105 M−1, and with 27.7 ± 0.2, 17.4 ± 0.1 and 8.4 ± 0.1 binding sites, respectively. However, κ carrageenan oligosaccharide had no affinity for G-CSF. The three carrageenans significantly inhibited G-CSF-induced growth of NFS-60 cells. The high sulfate content λ carrageenan could also induce the maturation of the cells, but relatively low sulfate content ι and κ carrageenans could not. The results suggested that G-CSF–carrageenan bindings were dependent on carrageenans’ sulfate contents and chain lengths, which could also affect the growth and differentiation of NFS-60 cells.