Polypeptides Related to Natriuretic Peptides and Methods of Their Identification and Use

Abstract

The present invention relates to the identification and use of polypeptides that bind to antibodies directed to a desired polypeptide of interest. Using natriuretic peptides and their precursors, and in particular BNP, as an example, the present invention describes a number of natriuretic peptides fragments produced in biological samples, most preferably blood-derived samples, that bind to antibodies directed to BNP. Because production of such fragments is an ongoing process that may be a function of, inter alia, the elapsed time between onset of an event triggering natriuretic peptide release into the tissues and the time the sample is obtained or analyzed; the elapsed time between sample acquisition and the time the sample is analyzed; the type of tissue sample at issue; the storage conditions; the quantity of proteolytic enzymes present; etc., such fragments may be used when both designing an assay for one or more natriuretic peptides, and when performing such an assay, in order to provide an accurate prognostic or diagnostic result.

1 . A purified antibody that specifically binds to at least one BNP polypeptide selected from the group consisting of BNP79-108, BNP77-106, BNP39-86, BNP53-85, BNP66-98, BNP30-106, BNP11-107, BNP9-106, BNP69-100, BNP76-107, BNP69-108, BNP80-108, BNP81-108, BNP83-108, BNP30-103, BNP3-108 and BNP79-106 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         2 . The antibody of  claim 1 , wherein the antibody is a monoclonal antibody. 
     
     
         3 . The antibody of  claim 1 , wherein the antibody is conjugated to a detectable label. 
     
     
         4 . The antibody of  claim 1 , wherein the antibody specifically binds to BNP79-108 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         5 . The antibody of  claim 1 , wherein the antibody specifically binds to BNP77-106 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         6 . The antibody of  claim 1 , wherein the antibody specifically binds to BNP39-86 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         7 . The antibody of  claim 1 , wherein the antibody specifically binds to BNP53-85 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         8 . The antibody of  claim 1 , wherein the antibody specifically binds to BNP66-98 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         9 . The antibody of  claim 1 , wherein the antibody specifically binds to BNP30-106 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         10 . The antibody of  claim 1 , wherein the antibody specifically binds to BNP11-107 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         11 . The antibody of  claim 1 , wherein the antibody specifically binds to BNP9-106 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         12 . The antibody of  claim 1 , wherein the antibody specifically binds to BNP69-100 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         13 . The antibody of  claim 1 , wherein the antibody specifically binds to BNP76-107 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         14 . The antibody of  claim 1 , wherein the antibody specifically binds to BNP69-108 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         15 . The antibody of  claim 1 , wherein the antibody specifically binds to BNP80-108 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         16 . The antibody of  claim 1 , wherein the antibody specifically binds to BNP81-108 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         17 . The antibody of  claim 1 , wherein the antibody specifically binds to BNP83-108 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         18 . The antibody of  claim 1 , wherein the antibody specifically binds to BNP30-103 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         19 . The antibody of  claim 1 , wherein the antibody specifically binds to BNP3-108 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         20 . The antibody of  claim 1 , wherein the antibody specifically binds to BNP79-106 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         21 . A method of diagnosis or prognosis of a disease, the method comprising
 performing an immunoassay on a human sample, the immunoassay comprising contacting an antibody to the human sample, wherein the antibody specifically binds to at least one BNP polypeptide selected from the group consisting of BNP79-108, BNP77-106, BNP39-86, BNP53-85, BNP66-98, BNP30-106, BNP11-107, BNP9-106, BNP69-100, BNP76-107, BNP69-108, BNP80-108, BNP81-108, BNP83-108, BNP30-103, BNP3-108 and BNP79-106 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP; and   correlating the result of said immunoassay to the presence or absence of said disease or the likelihood of said prognosis in the human from which said sample is obtained.   
     
     
         22 . The method of  claim 21 , wherein the disease is a cardiovascular disease. 
     
     
         23 . The method of  claim 21 , wherein the disease is selected from the group consisting of stroke, congestive heart failure (CHF), cardiac ischemia, systemic hypertension, and acute myocardial infarction 
     
     
         24 . The method of  claim 21 , comprising capturing one or more BNP polypeptides from the sample. 
     
     
         25 . The method of  claim 24 , wherein
 the capturing step comprises:   providing a SELDI probe comprising the antibody attached to a surface of a support;   contacting the antibody with a sample, whereby the antibody captures the at least one polypeptide from the sample; and   specifically measuring the presence or amount of the at least one captured BNP polypeptide by SELDI.   
     
     
         26 . The method of  claim 25 , wherein the SELDI is performed using a SELDI biochip with a chromatographic surface. 
     
     
         27 . The method of  claim 24 , further comprising capturing and measuring a polypeptide interactor of at least one of the one or more captured BNP polypeptides. 
     
     
         28 . The method of  claim 24 , wherein the one or more captured BNP polypeptides is/are measured by mass spectrometry. 
     
     
         29 . The method of  claim 28 , wherein the one or more captured BNP polypeptide is/are measured by SELDI. 
     
     
         30 . The method of  claim 24 , wherein the capturing captures a plurality of BNP polypeptides selected from the group and the specifically measuring a plurality of BNP polypeptides selected from the group. 
     
     
         31 . The method of  claim 21 , wherein the antibody specifically binds to BNP79-108 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         32 . The method of  claim 21 , wherein the antibody specifically binds to BNP77-106 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         33 . The method of  claim 21 , wherein the antibody specifically binds to BNP39-86 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         34 . The method of  claim 21 , wherein the antibody specifically binds to BNP53-85 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         35 . The method of  claim 21 , wherein the antibody specifically binds to BNP66-98 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         36 . The method of  claim 21 , wherein the antibody specifically binds to BNP30-106 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         37 . The method of  claim 21 , wherein the antibody specifically binds to BNP11-107 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         38 . The method of  claim 21 , wherein the antibody specifically binds to BNP9-106 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         39 . The method of  claim 21 , wherein the antibody specifically binds to BNP69-100 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         40 . The method of  claim 21 , wherein the antibody specifically binds to BNP76-107 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         41 . The method of  claim 21 , wherein the antibody specifically binds to BNP69-108 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         42 . The method of  claim 21 , wherein the antibody specifically binds to BNP80-108 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         43 . The method of  claim 21 , wherein the antibody specifically binds to BNP81-108 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         44 . The method of  claim 21 , wherein the antibody specifically binds to BNP83-108 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         45 . The method of  claim 21 , wherein the antibody specifically binds to BNP30-103 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         46 . The method of  claim 21 , wherein the antibody specifically binds to BNP3-108 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP. 
     
     
         47 . The method of  claim 21 , wherein the antibody specifically binds to BNP79-106 but does not bind to BNP1-108, BNP1-76, BNP77-108, or pre-pro-BNP.