Compositions and methods for capturing exosomes

Abstract

Compositions and kits for exosome capture include an antibody specifically binding the human asparagine-linked glycosylation 6 homolog (ALG6). The compositions and kits may be employed in a method for diagnosing a disease or condition in a subject.

What is claimed is: 
     
         1 . A composition comprising an anti-ALG6 antibody specifically binding a human alpha-1,3-glucosyltransferase (ALG6) peptide consisting essentially of the amino acid sequence of YEAQRHWQEIT (SEQ ID NO: 1). 
     
     
         2 . The composition of  claim 1 , wherein the anti-ALG6 antibody is a polyclonal antibody. 
     
     
         3 . The composition of  claim 1 , wherein the anti-ALG6 antibody is a monoclonal antibody. 
     
     
         4 . The composition of  claim 1 , wherein the anti-ALG6 antibody is conjugated to a detectable label. 
     
     
         5 . The composition of  claim 1 , wherein the anti-ALG6 antibody is attached to a solid substrate. 
     
     
         6 . A kit for capturing exosomes and detecting a disease-associated biomarker, comprising:
 an anti-ALG6 antibody; and   at least one disease-associated biomarker binding agent.   
     
     
         7 . The kit of  claim 6 , wherein the anti-ALG6 antibody is attached to a solid substrate. 
     
     
         8 . The kit of  claim 6 , wherein the disease-associated biomarker binding agent comprises a detection antibody or a nucleic acid. 
     
     
         9 . The kit of  claim 6 , wherein the anti-ALG6 antibody specifically binds to a human alpha-1,3-glucosyltransferase (ALG6) peptide comprising amino acid sequence of SEQ ID NO: 1. 
     
     
         10 . The kit of  claim 6 , further comprising a plurality of centrifuge filters having a pore size smaller than 90 nm. 
     
     
         11 . The kit of  claim 6 , further comprising a detectable label selected from the group consisting of radioisotopes, fluorescent compounds, chemiluminescent compounds, bioluminescent compounds, nucleotide chromophores, substrates, enzymes, enzyme substrates luminescent compounds and colloidal gold and secondary antibodies specifically binding to the antibody in  claim 6 . 
     
     
         12 . A method for diagnosing a disease or a condition in a subject, comprising:
 (a) contacting a bodily fluid sample from the subject with an anti-ALG6 antibody under conditions suitable for binding the exosomes to capture agent to form bound exosome-anti-ALG6 complexes;   (b) contacting the complexes with at least one disease- or condition-associated biomarker binding agent suitable for detecting at least one disease- or condition-associated biomarkers present in the exosomes; and   (c) determining whether the exosomes comprise at least one detectable disease- or condition-associated biomarker,   wherein detection of the at least one disease- or condition-associated biomarker in step (c) is indicative of a disease or condition in the subject and wherein lack of detection of the at least one disease- or condition-associated biomarker in step (d) is indicative of the absence of the disease or condition in the subject.   
     
     
         13 . The method of  claim 12 , wherein the anti-ALG6 antibodies in step (a) are attached to a solid substrate. 
     
     
         14 . The method of  claim 12 , wherein prior to step (a) the bodily fluid sample is passed through a centrifuge filter suitable for isolating and concentrating exosomes, wherein the filter has a pore size smaller than 90 nm. 
     
     
         15 . The method of  claim 12 , wherein the at least biomarker binding agent comprises at least one detection antibody specific for a disease- or condition-associated biomarker. 
     
     
         16 . The method of  claim 15 , wherein detection of the at least one disease- or condition-associated biomarker further comprises the step of contacting the detection antibody with a secondary antibody binding to the detection antibody, wherein the secondary antibody comprises a detectable label. 
     
     
         17 . The method of  claim 12 , wherein the anti-ALG6 antibody specifically binds to a human alpha-1,3-glucosyltransferase (ALG6) peptide comprising amino acid sequence of SEQ ID NO: 1. 
     
     
         18 . The method of  claim 12 , wherein the at least one biomarker binding agent comprises at least one nucleic acid specific for a disease- or condition-associated biomarker. 
     
     
         19 . The method of  claim 12 , wherein the bodily fluid sample comprises blood or plasma. 
     
     
         20 . The method of  claim 12 , wherein the bodily fluid sample comprises urine.