Effects of ticlopidine on monoclonal anti-CD9 antibody-induced platelet aggregation and microparticle generation.
We analyzed the effects of ticlopidine on platelet aggregation and on microparticle (MP) formation when platelets were exposed to a monoclonal anti-CD9 antibody (NNKY1-19) in vitro. Even when NNKY1-19-induced platelet aggregation was completely inhibited by preincubation with anti-GPIIb/IIIa antibody or Arg-Gly-Asp-Ser, or by using washed platelets from a Glanzmann's thrombasthenia patient, the formation of MP was still observed. Prostaglandin E1 and protein kinase C antagonists (H-7 and staurosporine) inhibited both NNKY1-19-induced aggregation and MP formation. Ticlopidine or aspirin plus apyrase scarcely affected NNKY1-19-induced platelet aggregation, except to prolong the lag time. However, ticlopidine significantly inhibited MP formation (p less than 0.01). These results suggest that ticlopidine inhibits NNKY1-19-induced MP formation by a different mechanism to that of the other antagonists, and that this mechanism is unrelated to the inhibition of platelet aggregation.
Nomura
S
S
First Department of Internal Medicine, Kansai Medical University, Osaka, Japan.
Nagata
H
H
Suzuki
M
M
Iwata
K
K
Kawakatsu
T
T
Kido
H
H
Fukuroi
T
T
Yamaguchi
K
K
Yanabu
M
M
Soga
T
T
D000255:Adenosine Triphosphate / Q000097:blood; D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology*; D015703:Antigens, CD / Q000276:immunology*; D002118:Calcium / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D005434:Flow Cytometry; D005557:Formaldehyde; D006801:Humans; D008562:Membrane Glycoproteins / Q000276:immunology*; D008969:Molecular Sequence Data; D010316:Particle Size; D010974:Platelet Aggregation / Q000187:drug effects* / Q000276:immunology; D011108:Polymers; D060245:Tetraspanin 29; D013988:Ticlopidine / Q000494:pharmacology*
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; C554869:CD9 protein, human; D008562:Membrane Glycoproteins; D011108:Polymers; D060245:Tetraspanin 29; D005557:Formaldehyde; D000255:Adenosine Triphosphate; D013988:Ticlopidine; D002118:Calcium; C003043:paraform