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This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Miller, J. L. Articles by Hustad, K. O. Search for Related Content PubMed PubMed Citation Articles by Miller, J. L. Articles by Hustad, K. O. Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  Characterization of a platelet membrane protein of low molecular weight associated with platelet activation following binding by monoclonal antibody AG-1 JL Miller, JM Kupinski and KO Hustad With the exception of the major platelet glycoproteins IIb/IIIa and Ib, which function as receptors for fibrinogen and von Willebrand factor, little is presently known regarding the possible role of other platelet surface proteins in mediating platelet aggregation. We report the production of a murine monoclonal antibody (AG-1) recognizing human platelet membrane surface protein of relatively low molecular weight (mol wt) that may be involved in this process. AG-1 added to human platelet-rich plasma induces dense granule secretion and aggregation, with lag phase and maximal extent of aggregation dependent on antibody concentration. Aggregation induced by AG-1 is inhibited by AG-1 Fab fragments, indicating that the response is not Fc receptor-mediated. Although AG-1 continues to produce platelet shape change in the presence of EDTA, aggregation is fully inhibited and appears to be mediated by fibrinogen binding to glycoproteins IIb/IIIa. AG-1 is a potent stimulus of thromboxane formation, but full inhibition of thromboxane production by 30 mumol/L indomethacin does not significantly inhibit platelet aggregation induced by 25 micrograms/mL AG-1, indicating that aggregation induced by AG-1 may proceed by way of an endoperoxide-independent pathway. Quantitation of AG-1 Fab binding to platelets reveals approximately 65,000 binding sites per platelet. When intact platelets are radioiodinated, immunoprecipitation of NP-40 lysates by AG-1 reveals an intensely labeled protein with an apparent mol wt of approximately 21,000 daltons, and several additional bands in the mol wt range of 22,000 to 28,000 daltons, all sharing the AG-1 epitope. These bands appear to be distinct from glycoprotein IX or from the beta-chains of glycoprotein Ib or IIb. Finally, studies with platelets labeled by the periodate-[3H]borohydride procedure suggest the possibility of complex formation between subpopulations of glycoprotein Ib and the low-mol-wt glycoproteins recognized by AG-1. Volume 68, Issue 3, pp. 743-751, 09/01/1986 Copyright © 1986 by The American Society of Hematology CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? This article has been cited by other articles: M. Yanabu, Y. Ozaki, S. Nomura, T. Miyake, Y. Miyazaki, H. Kagawa, Y. Yamanaka, N. Asazuma, K. Satoh, S. Kume, et al. Tyrosine Phosphorylation and p72syk Activation by an Anti-Glycoprotein Ib Monoclonal Antibody Blood, March 1, 1997; 89(5): 1590 - 1598. [Abstract] [Full Text] [PDF]

	Copyright © 1986 by American Society of Hematology         Online ISSN: 1528-0020