Specific binding between human neutrophils and heparin

Heparin binding on polymorphonuclear leucocytes (PMNL) was characterized. Heparin binding was specific, rapid, saturable and reversible. One single class of heparin binding sites was found with a dissociation constant of 1.22 μmol/1 and 7.7×106 sites per PMNL. The binding was independent of the anticoagulant activity of heparin. Heparin affinity chromatography on radio‐iodinated cell lysates followed by polyacrylamide gel electrophoresis in the presence of sodium dodecylsulphate revealed a 130 kD heparin binding protein. Heparin binding was inhibited by disodium salt of ethylenediamine tetraacetic acid. Cell surface bound heparin was functionally inactive and did not affect the inactivation of thrombin by antithrombin III. Our study demonstrates that heparin interacts with PMNL by a cell‐surface binding protein. These instructions could be consistent with the modifications of some PMNL functional properties in the presence of heparin.