Effect of a new monoclonal anti-glycoprotein IX antibody, KMP-9, on high shear-induced platelet aggregation.
Human platelet glycoprotein Ib/IX complex acts as a receptor for von Willebrand factor. It is widely accepted that glycoprotein Ib is the essential receptor component, but the role of glycoprotein IX is still unclear. We produced a new monoclonal anti-glycoprotein IX antibody (KMP-9) by the hybridoma technique using platelets from a patient with Glanzmann's thrombasthenia. The epitope of KMP-9 was localized to the C-terminal 8 kD fragment of glycoprotein IX using ELISA analysis of polyethylene-pin-synthesized peptides, as well as Western blot analysis of platelets after digestion with N-glycosidase and Staphylococcus aureus V8 protease. KMP-9 partially inhibited high shear stress-induced platelet aggregation, but had no effect on aggregation induced by ristocetin or low shear stress. Its inhibitory effect on high shear stress-induced aggregation was weaker than that of anti-glycoprotein Ib or anti-glycoprotein IIb/IIIa monoclonal antibodies. A 21-mer synthetic peptide (glycoprotein IX L110-G130) inhibited the binding of KMP-9 to platelets. It also competively inhibited the suppression of high shear stress-induced platelet aggregation by KMP-9, but had no direct effect on this aggregation. KMP-9 may be useful to clarify the physiological role of GPIX.
Miyake
T
T
First Department of Internal Medicine, Kansai Medical University, Osaka, Japan.
Nomura
S
S
Komiyama
Y
Y
Miyazaki
Y
Y
Kagawa
H
H
Masuda
M
M
Takahashi
H
H
Fujimura
Y
Y
Ikeda
Y
Y
Fukuhara
S
S
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D001665:Binding Sites; D006801:Humans; D008969:Molecular Sequence Data; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000276:immunology*; D013314:Stress, Mechanical
D000911:Antibodies, Monoclonal; D010975:Platelet Aggregation Inhibitors; D019038:Platelet Glycoprotein GPIb-IX Complex