title: The parasitic hematophagous worm Haemonchus contortus inhibits human platelet aggregation and adhesion: partial purification of a platelet inhibitor.
abstract: Blood sucking parasites elaborate mechanisms to counteract the hemostatic system of their victim. Haemonchus contortus worms use several mechanisms directed against the normal platelet hemostatic function. Platelet adhesion onto collagen and fibrinogen, and the ristocetin-mediated interaction of von Willebrand Factor with glycoprotein (GP) Ib were inhibited by the protein extract of adult worms. Also platelet aggregation induced by collagen, thrombin, ADP, ristocetin or A23187 was inhibited. Although we obtained evidence for interference with fibrinogen binding to GPIIb/IIIa, the strongest inhibition was seen when the agonists collagen or thrombin were used. A small multisubunit inhibitor of collagen-induced platelet aggregation was partially purified using anion exchange chromatography, gel filtration and RP-HPLC. The inhibitor has a pI between 4 and 6.5, elutes with a molecular weight of 23,800 Da after gel filtration, and is part of the elaborate broad-spectrum antiplatelet activity that results in the potent synergistic anti-hemostatic cocktail produced by H. contortus.
authors.affiliation: Laboratory for Thrombosis Research, IRC, KU Leuven Campus Kortrijk, Belgium.
authors.forename: Annick
authors.initials: A
authors.lastname: Crab
authors.forename: Wim
authors.initials: W
authors.lastname: Noppe
authors.forename: Conny
authors.initials: C
authors.lastname: Pelicaen
authors.forename: Karen
authors.initials: K
authors.lastname: Van Hoorelbeke
authors.forename: Hans
authors.initials: H
authors.lastname: Deckmyn
mesh_terms: D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003094:Collagen / Q000494:pharmacology; D006189:Haemonchus / Q000737:chemistry*; D006801:Humans; D010973:Platelet Adhesiveness / Q000187:drug effects*; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000302:isolation & purification* / Q000494:pharmacology; D012310:Ristocetin / Q000494:pharmacology; D013917:Thrombin / Q000494:pharmacology; D014020:Tissue Extracts / Q000494:pharmacology
chemical_list: D010975:Platelet Aggregation Inhibitors; D014020:Tissue Extracts; D012310:Ristocetin; D000001:Calcimycin; D003094:Collagen; D013917:Thrombin