Anti-t. cruzi antibodies and methods of use

Abstract

The present disclosure is directed to reagents and methods of using the reagents to detect epitopes of Trypanosoma cruzi.

1 .- 42 . (canceled) 
     
     
         43 . An immunodiagnostic reagent comprising one or more antibodies that specifically bind to a  T. cruzi  FRA polypeptide, wherein the  T. cruzi  FRA polypeptide comprises an amino acid sequence of SEQ ID NO: 8, and wherein each of the one or more antibodies comprises a variable light chain region (V L ) comprising an amino acid sequence of SEQ ID NO: 26 and a variable heavy chain region (V H ) comprising an amino acid sequence of SEQ ID NO: 28. 
     
     
         44 . The immunodiagnostic reagent according to  claim 43 , which comprises two or more antibodies. 
     
     
         45 . The immunodiagnostic reagent according to  claim 43 , wherein each of the one or more antibodies comprises at least one binding constant selected from: an association rate constant (k a ) between about 2.0×10 5  M −1 s −1  to about 6.0×10 6  M −1 s −1 ; a dissociation rate constant (k d ) between about 2.0×10 −5  s −1  to about 8.0×10 −4  s −1 ; and an equilibrium dissociation constant (K D ) between about 3.3×10 −12  M to about 4.0×10 −9  M. 
     
     
         46 . The immunodiagnostic reagent according to  claim 43 , wherein the one or more antibodies is a chimeric antibody. 
     
     
         47 . The immunodiagnostic reagent of  claim 43 , wherein the one or more antibodies is the antibody expressed by the cell line deposited with the American Type Tissue Collection (ATCC) under accession number PTA-8142. 
     
     
         48 . The immunodiagnostic reagent of  claim 43 , which is a detection reagent, a standardized reagent, or a positive control reagent. 
     
     
         49 . An antibody that specifically binds to a  T. cruzi  FRA polypeptide comprising the amino acid sequence of SEQ ID NO: 8, wherein the antibody comprises a variable light chain region (V L ) comprising an amino acid sequence of SEQ ID NO: 26 and a variable heavy chain region (V H ) comprising an amino acid sequence of SEQ ID NO: 28. 
     
     
         50 . The antibody according to  claim 49 , which comprises at least one binding constant selected from: an association rate constant (k a ) between about 2.0×10 5  M −1 s −1  to about 6.0×10 6  M −1 s −1 ; a dissociation rate constant (k d ) between about 2.0×10 −5  s −1  to about 8.0×10 −4  s −1 ; and an equilibrium dissociation constant (K D ) between about 3.3×10 −12  M to about 4.0×10 −9  M. 
     
     
         51 . The antibody of  claim 49 , which is a chimeric antibody. 
     
     
         52 . The antibody of  claim 49 , which is the antibody expressed by the cell line deposited with the ATCC under accession number PTA-8142. 
     
     
         53 . A cell line deposited with the ATCC under accession number PTA-8142. 
     
     
         54 . A method of standardizing a  T. cruzi  detection assay comprising using the immunodiagnostic reagent of  claim 43  as a sensitivity panel. 
     
     
         55 . A method for detecting a  T. cruzi  FRA antigen comprising the steps of:
 (a) contacting a test sample suspected of containing a  T. cruzi  FRA antigen with the immunodiagnostic reagent of  claim 43  under conditions that allow formation of chimeric antibody:antigen complexes; and   (b) detecting any chimeric antibody:antigen complexes formed as indicating the presence of the  T. cruzi  FRA antigen.   
     
     
         56 . The method of  claim 55 , wherein the chimeric antibody comprises a detectable label, or wherein the antibody:antigen complexes are contacted with a detectably-labeled secondary antibody or fragment thereof. 
     
     
         57 . A method for detecting a  T. cruzi  FRA antibody comprising the steps of:
 (a) contacting a test sample suspected of containing a  T. cruzi  FRA antibody with one or more  T. cruzi  FRA antigens specific for the  T. cruzi  antibody under conditions that allow formation of antigen:antibody complexes; and   (b) detecting any antigen:antibody complexes formed as indicating the presence of a  T. cruzi  FRA antibody, wherein the immunodiagnostic reagent of claim  43  is used as a positive control or standardization reagent, and wherein the  T. cruzi  FRA antigen comprises the amino acid sequence of SEQ ID NO: 8.   
     
     
         58 . A diagnostic kit for the detection of  T. cruzi  comprising the immunodiagnostic reagent  claim 43  and instructions for use. 
     
     
         59 . An isolated polynucleotide encoding the V L  region of the antibody of  claim 49 , which comprises the nucleic acid sequence of SEQ ID NO: 25. 
     
     
         60 . An isolated polynucleotide encoding the V H  region of the antibody of  claim 49 , which comprises the nucleic acid sequence of SEQ ID NO: 27. 
     
     
         61 . A method of purifying a  T. cruzi  FRA antigen having at least 70% sequence identity to the amino acid sequence of SEQ ID NO: 8, which method comprises:
 (a) contacting a sample suspected of containing a  T. cruzi  FRA antigen with the immunodiagnostic reagent of  claim 43  under conditions that allow formation of antibody:antigen complexes;   (b) isolating the antibody:antigen complexes formed; and   (c) separating the FRA antigen from the antibody.