Galectin-3 immunoassay

Abstract

The present invention relates to methods and compositions for specifically and quantitatively detecting galectin-3 in a sample. Embodiments of the invention include a detection assay in which a capture binding moiety and a labeled binding moiety specifically recognize non-overlapping epitopes on the N-terminus of galectin-3. Further embodiments are directed to a method for establishing ranges of galectin-3 concentrations indicative of the presence and severity of heart failure in a subject and a method for predicting the clinical outcome of a subject based upon galectin-3 concentration.

1 . A kit for detecting a concentration of galectin-3 in a sample, the kit comprising
 first and second binding moieties, one being labeled with a detectable label, wherein the first binding moiety comprises an M3/38 monoclonal antibody capable of binding to galectin-3, and wherein the second binding moiety comprises an 87B5 monoclonal antibody capable of binding to galectin 3.   
     
     
         2 . The kit of  claim 1  wherein the detectable label is an enzyme, a chemiluminescent compound, or a fluorophore. 
     
     
         3 . The kit of  claim 1 , wherein the first and second binding moieties form a sandwich assay capable of providing a result indicative of a galectin-3 concentration above a threshold. 
     
     
         4 . (canceled) 
     
     
         5 . The kit of  claim 1 , further comprising a human galectin-3 protein standard. 
     
     
         6 . (canceled) 
     
     
         7 . The kit of  claim 1 , wherein the mouse antibody M3/38 monoclonal antibody is immobilized on a solid phase. 
     
     
         8 . A method for detecting the level of human galectin-3 in at least one sample from a subject, the method comprising:
 contacting the at least one sample with a first binding moiety capable of binding to galectin-3 comprising an M3/38 monoclonal antibody immobilized on a solid surface, wherein the first binding moiety captures the human galectin-3 in the at least one sample to form a first complex;   contacting the first complex with a second binding moiety capable of binding to galectin-3 comprising an 87B5 monoclonal antibody and a detectable label, wherein the second binding moiety binds to the first complex to form a second complex comprising the detectable label; and   detecting the detectable label of the second complex, thereby detecting the level of the human galectin-3 in the at least one sample.   
     
     
         9 . The method of  claim 8 , wherein the detecting provides a qualitative result indicative of the level of the human galectin-3 above a threshold galectin-3 concentration. 
     
     
         10 . The method of  claim 9 , wherein the threshold galectin-3 concentration in the at least one sample is in the range of 15-20 ng/ml. 
     
     
         11 . The method of  claim 9 , wherein the threshold galectin-3 concentration in the at least one sample is in the range of 20-25 ng/ml. 
     
     
         12 . The method of  claim 9 , wherein the threshold galectin-3 concentration in the at least one sample is in the range of 25-30 ng/ml. 
     
     
         13 . The method of  claim 9 , wherein the threshold galectin-3 concentration in the at least one sample is in the range of 30-35 ng/ml. 
     
     
         14 . The method of  claim 8 , wherein the method provides a quantitative result indicative of the galectin-3 concentration. 
     
     
         15 . The method of  claim 8 , further comprising the additional step of comparing the result of the method to data correlating the concentration of galectin-3 in the sample with data relating the result with risk of the subject developing symptoms of heart failure (HF) or with severity of diagnosed HF disease of the subject, wherein the sample is a whole blood, serum, or plasma sample. 
     
     
         16 . The method of  claim 8 , wherein the at least one sample includes a first sample from the subject and a second sample taken from the subject at a different time than the first sample. 
     
     
         17 . A method for detecting a risk of development or progression of heart failure in a subject, the method comprising the steps of:
 obtaining from the subject at least one sample comprising whole blood, serum, or plasma;   contacting the at least one sample with a first binding moiety capable of binding to galectin-3 comprising an M3/38 monoclonal antibody immobilized on a solid surface, wherein the first binding moiety captures the human galectin-3 in the at least one sample to form a first complex;   contacting the first complex with a second binding moiety capable of binding to galectin-3 comprising a 87B5 monoclonal antibody and a detectable label, wherein the second binding moiety binds to the first complex to form a second complex comprising the detectable label;   detecting the detectable label of the second complex, thereby detecting the level of the human galectin-3 in the at least one sample; and   determining whether the level of the human galectin 3 exceeds a threshold of at least 15 ng/ml,   thereby detecting the risk of development or progression of heart failure in the subject.   
     
     
         18 . The method of  claim 17 , wherein the threshold is 15-20 ng/ml. 
     
     
         19 . The method of  claim 17 , wherein the threshold is 20-25 ng/ml. 
     
     
         20 . The method of  claim 17 , wherein the threshold is 25-30 ng/ml. 
     
     
         21 . The method of  claim 17 , wherein the threshold is 30-35 ng/ml. 
     
     
         22 . The kit of  claim 1 , wherein the 87B5 monoclonal antibody is immobilized on a solid phase. 
     
     
         23 . The method of  claim 8 , further comprising the step of correlating the level of the human galectin-3 with a severity of diagnosed heart failure of the subject. 
     
     
         24 . The method of  claim 16 , wherein the at least one sample includes a plurality of samples from the subject. 
     
     
         25 . The method of  claim 16 , wherein the at least one sample includes samples taken weekly. 
     
     
         26 . The method of  claim 16 , wherein the at least one sample includes samples taken monthly. 
     
     
         27 . The method of  claim 16 , wherein the at least one sample includes samples taken yearly. 
     
     
         28 . A method for detecting a level of a human galectin-3 in a sample from a subject, the method comprising:
 contacting the sample with a first binding moiety capable of binding to galectin-3 comprising a 87B5 monoclonal antibody immobilized on a solid surface, wherein the first binding moiety captures the human galectin-3 in the sample to form a first complex;   contacting the first complex with a second binding moiety capable of binding to galectin-3 comprising an M3/38 monoclonal antibody and a detectable label, wherein the second binding moiety binds to the first complex to form a second complex comprising the detectable label; and   detecting the detectable label of the second complex, thereby detecting the level of the human galectin-3 in the sample.   
     
     
         29 . The method of  claim 28 , further comprising the steps of providing a calibration curve and plotting the level of the human galectin-3 on the calibration curve.