Immunochemical identification of a thrombospondin-like structure in an arterial microfibrillar extract.
Arterial microfibrils contain a 128 Kd collagenase and pepsin resistant glycoprotein (GP 128) essential for their ability to induce platelet aggregation. A previous report (Fauvel F. et al, (1984) Biochem. Biophys. Res. Comm., 123, 114-120) showed that GP 128 and thrombospondin (TSP) synthetized by endothelial cells each inhibited the aggregation of platelets by microfibrils and not by collagen. We used a monospecific antiplatelet TSP IgG in an immunoblotting assay for the identification of a TSP-like structure in untreated, collagenase-treated and pepsin-treated arterial microfibrils. The only constituent recognized in the three samples of microfibrils was GP 128. Fab fragments of this IgG provoked a dose dependent inhibition of the microfibril induced platelet aggregation (50% inhibition with 0.25 mg, 100% inhibition with 1 mg); in contrast, they did not affect collagen induced aggregation. The results indicate that a glycoprotein constituent with a thrombospondin-like antigenicity is involved in the thrombogenic properties of arterial microfibrils.
Fauvel-Lafeve
F
F
Unité de Recherches sur la Thrombose et l'Hémostase, U 150 de l'INSERM, UA 334 CNRS, Hôpital Saint-Louis, Paris.
Legrand
Y J
YJ
D008841:Actin Cytoskeleton / Q000032:analysis*; D001792:Blood Platelets / Q000378:metabolism; D003599:Cytoskeleton / Q000032:analysis*; D006023:Glycoproteins / Q000276:immunology / Q000302:isolation & purification*; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D007231:Infant, Newborn; D003012:Microbial Collagenase; D010434:Pepsin A; D010974:Platelet Aggregation; D012701:Serotonin / Q000378:metabolism; D019699:Thrombospondins; D014469:Umbilical Arteries / Q000032:analysis
D006023:Glycoproteins; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D019699:Thrombospondins; D012701:Serotonin; D010434:Pepsin A; D003012:Microbial Collagenase