Detection of platelet-derived shed CD31

摘要

The present invention relates to various soluble forms of CD31, including a novel form which is shed by activated platelets and released into the circulation. Methods for detecting said soluble forms of CD31 are disclosed, as are methods of specifically 1 detecting said platelet-derived shed CD31 and the use of such methods as a diagnostic tool.

主权项

1. A method for detecting a platelet-derived shed ectodomain of a CD31 protein, a lymphocyte-derived shed ectodomain of a CD31 protein, and a soluble splice variant of said CD31 protein in a biological sample, wherein said platelet-derived shed ectodomain of a CD31 protein is a CD31 fragment (i) comprising the 1st to 5th extracellular immunoglobulin (lg)-like domains and the whole or a part of the 6th extracellular lg-like domain of said full-length CD31 protein, said part of the 6th extracellular lg-like domain comprising an amino acid sequence corresponding to residues 494 to 501 of human CD31 protein and (ii) not comprising the intracellular domain of said full-length protein, the method comprising:
a) providing a capture antibody wherein said capture antibody specifically binds to an epitope located in a region that is present on said platelet-derived shed ectodomain, on said lymphocyte-derived shed ectodomain and on said splice variant; b) providing a first discriminating antibody which specifically binds to an epitope located in a region that is present on said platelet-derived shed ectodomain and said splice variant and absent from said lymphocyte-derived shed ectodomain; c) providing a second discriminating antibody which specifically binds to an epitope located in a region that is present on said splice variant and absent from said platelet-derived shed ectodomain and from said lymphocyte-derived shed ectodomain; d) providing a third discriminating antibody which specifically binds to an epitope located in a region that is present on said platelet-derived shed ectodomain, on said lymphocyte-derived shed ectodomain and on said splice variant;wherein said discriminating antibodies are labeled with a detectable label;
e) contacting said antibodies with the biological sample; f) measuring the signal obtained from the label associated with each discriminating antibody;wherein the capture antibody and the third discriminating antibody bind within the region defined by the 1st, 2nd, 3rd, 4th and 5th extracellular domains of said CD31, the first discriminating antibody binds within the 6th Ig-like extracellular domain of said CD31, and the second discriminating antibody binds to the intracellular domain of said CD31.