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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 Siddiqui, F. A. Articles by Lian, E. C. Search for Related Content PubMed PubMed Citation Articles by Siddiqui, F. A. Articles by Lian, E. C. Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  Platelet-agglutinating protein P37 from a thrombotic thrombocytopenic purpura plasma forms a complex with human immunoglobulin G FA Siddiqui and EC Lian Hemophilia and Thrombosis Center, University of Miami School of Medicine, FL. We have previously reported the purification of a 37-kd platelet- agglutinating protein (PAP p37) from the plasma of a patient with thrombotic thrombocytopenic purpura (TTP) that was shown to be present in a subset of TTP patients. The platelet agglutination induced by PAP p37 has been shown to be inhibited by IgG from normal human adults and the same TTP patient after recovery. To elucidate the mechanism of inhibition of IgG, the interaction between PAP p37 and IgG was studied. The complex formation was demonstrated by the binding of fluid-phase IgG from normal adults and the same TTP patient after recovery to adsorbed PAP by using an enzyme-linked immunosorbent assay. The binding was specific, concentration dependent, and saturable. IgG purified from a 5-month-old baby and the same TTP patient during active disease did not form complex with PAP p37. The IgG covalently cross-linked to Sepharose 4B bound 125I-PAP p37 but not 125I-fibrinogen. Sucrose density gradient ultracentrifugation of a mixture of 125I-PAP p37 and IgG also revealed the fluid-phase complex formation with a sedimentation value of 19S. Complexes of molecular weight ranging from 180,000 to over 350,000 daltons were also detected by molecular sieve chromatography. The IgG that was bound to PAP p37 conjugated to Sepharose 4B inhibited the agglutination of washed platelets induced by TTP plasma containing PAP p37, whereas the IgG that was not bound to PAP p37 did not have a significant inhibitory effect. The complex formation between PAP p37 and specific IgG is likely to account for the in vitro inhibition of TTP plasma-induced agglutination and, at least partly, the in vivo successful treatment with specific IgG-containing normal plasma. Volume 71, Issue 2, pp. 299-304, 02/01/1988 Copyright © 1988 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: F. A. Siddiqui, A. Amirkhosravi, M. Amaya, H. Desai, T. Meyer, and J. L. Francis Purification and Properties of Human Melanoma Cell Tissue Factor Clinical and Applied Thrombosis/Hemostasis, October 1, 2001; 7(4): 289 - 295. [Abstract] [PDF]

	Copyright © 1988 by American Society of Hematology         Online ISSN: 1528-0020