Heparin and heparan sulfate bind interleukin-10 and modulate its activity

• Published in: Blood 2000-09, Vol.96 (5), p.1879-1888
• Main Authors: Salek-Ardakani, Shahram, Arrand, John R., Shaw, David, Mackett, Mike
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Antigens, CD - drug effects; Antigens, CD - metabolism; Binding, Competitive - drug effects; Biological and medical sciences; Cells, Cultured; Chlorates - pharmacology; Chromatography, Affinity; Dose-Response Relationship, Drug; Flow Cytometry; Glycosaminoglycans - pharmacology; Heparin - metabolism; Heparin - pharmacology; Heparitin Sulfate - metabolism; Heparitin Sulfate - pharmacology; Humans; Immunomodulators; Interleukin-10 - metabolism; Interleukin-10 - pharmacology; Kinetics; Leukocytes, Mononuclear - cytology; Leukocytes, Mononuclear - drug effects; Leukocytes, Mononuclear - metabolism; Macrophages - cytology; Macrophages - drug effects; Macrophages - metabolism; Medical sciences; Molecular Sequence Data; Monocytes - cytology; Monocytes - drug effects; Monocytes - metabolism; Pharmacology. Drug treatments; Receptors, IgG - drug effects; Receptors, IgG - metabolism; Recombinant Proteins - metabolism; Recombinant Proteins - pharmacology; Sepharose - analogs & derivatives
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V96.5.1879

Glycosaminoglycans (GAG) are a group of negatively charged molecules that have been shown to bind and directly regulate the bioactivity of growth factors and cytokines such as basic fibroblast growth factor, transforming growth factor-β, IL-7, and interferon-γ. The ability of GAG to interact with human IL-10 (hIL-10) and the effect of these interactions on its biologic activity were analyzed. It was demonstrated by affinity chromatography that hIL-10 binds strongly to heparin–agarose at physiological pH. Biosensor-based binding kinetic analysis indicated an equilibrium dissociation constant, Kd, of 54 nmol/L for this interaction. Human IL-10 stimulated CD16 and CD64 expression on the monocyte/macrophage population within peripheral blood mononuclear cells, with optimal concentrations between 1 and 10 ng/mL. Soluble heparin, heparan sulfate, chondroitin sulfate, and dermatan sulfate were shown to inhibit the hIL-10–induced expression of CD16 and CD64 in a concentration-dependent manner. Heparin and heparan sulfate were most effective with IC50 values of 100 to 500 μg/mL. Considerably higher concentrations of dermatan sulfate and chondroitin 4-sulfate were required with an IC50 of 2000 to 5000 μg/mL, whereas chondroitin 6-sulfate was essentially inactive. The antagonistic effect of heparin on hIL-10 activity was shown to be dependent on N-sulfation, inasmuch as de-N-sulfated heparin had little or no inhibitory effect on the IL-10– induced expression of CD16, whereas the effect of de-O-sulfated heparin was comparable to that of unmodified heparin. Furthermore, the inhibition of cell-bound proteoglycan sulfation reduced the hIL-10–mediated expression of CD16 molecules on monocytes/macrophages. Taken together, these findings support the hypothesis that soluble and cell-surface GAG and, in particular, their sulfate groups are important in binding and modulation of hIL-10 activity.