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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1992-3-16
pubmed:abstractText
Platelets contain a pool of endogenous adhesive proteins that can be released and may bind to surface membrane receptors under appropriate conditions. Because the binding of exogenous fibrinogen to platelets was shown previously to be accompanied by a time-dependent decrease in fibrinogen accessibility to antibody and enzymes, studies were performed to evaluate changes in the expression of endogenous fibrinogen released from thrombin-stimulated platelets using monospecific polyclonal and monoclonal antibody F(ab')2 fragments. Parallel studies were performed to compare the expression of released fibronectin and von Willebrand factor (vWF). Binding of polyclonal antibody F(ab')2 fragments directed against individual adhesive proteins was inhibited by EDTA or the 10E5 monoclonal antibody, suggesting that fibrinogen, fibronectin, and vWF expression was mediated, in large part, by divalent cation-dependent interactions with the glycoprotein IIb-IIIa complex. Interestingly, when polyclonal antibody F(ab')2 fragments were added to platelet suspensions at discrete times after thrombin stimulation, antifibrinogen F(ab')2 binding decreased by 72% +/- 15% (mean +/- SD, n = 22) over a 60-minute time course, whereas antifibronectin and anti-vWF antibody F(ab')2 fragment binding changed minimally (6% +/- 23%, n = 22 and 3% +/- 26%, n = 14, respectively). Similar observations were made with monoclonal antibodies. Parallel experiments using 125I-labeled fibrinogen as a marker indicated that the observed decrease in antifibrinogen F(ab')2 binding was not accompanied by fibrinogen dissociation. Moreover, antibody accessibility to platelet-bound fibrinogen could be restored after Triton X-100 platelet lysis. The data suggest that fibrinogen, fibronectin, and vWF are not coordinately expressed on thrombin-stimulated platelets. Rather, fibrinogen expression appears transient compared with the expression of fibronectin and vWF. The ability of platelets to secrete and organize adhesive proteins on their surface is likely to have important implications for hemostasis and thrombosis.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-4971
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
79
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
948-53
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Adhesive protein expression on thrombin-stimulated platelets: time-dependent modulation of anti-fibrinogen, -fibronectin, and -von Willebrand factor antibody binding.
pubmed:affiliation
Department of Pathology, SUNY, Stony Brook.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.