Method of detecting antibodies to HCV

Abstract

A family of cDNA sequences derived from hepatitis C virus (HCV) are provided. These sequences encode antigens which react immunologically with antibodies present in individuals with non-A non-B hepatitis (NANBV), but which are absent from individuals infected with hepatitis A virus, or hepatitis B virus, and also are absent in control individuals. The HCV cDNA sequences lack substantial homology to the sequences of hepatitis delta virus (HDV) and HBV. A comparison of the sequences of amino acids encoded in the HCV cDNA with the sequences of Flaviviruses indicated that HCV may be related to the Flaviviruses. The HCV cDNA sequences and the polypeptides encoded therein are useful as reagents for the detection and therapy of HCV. The reagents provided in the invention are also useful for the isolation of NANBV agent(s), for the propagation of these agents in tissue culture, and for the screening of antiviral agents for HCV.

1 . An immunoassay method for detecting antibodies directed against a hepatitis C virus (HCV) antigen comprising: 
 (a) incubating a sample suspected of containing anti-HCV antibodies with a polypeptide comprising an epitope of the HCV, under conditions which allow the formation of an antibody-antigen complex; and    (b) detecting the antibody-antigen complex containing the polypeptide, said polypeptide having the amino acid sequence: 
 Gln-Gly-Met-Met-Leu-Ala-Glu-Gln-Phe-Lys-Gln-Lys-Ala-Leu-Gly-Leu-Leu-Gln-Thr-Ala-Ser-Arg-Gln-Ala-Glu-Val-X 
 wherein X is —OH or —NH 2 .  
 
   
   
   
       2 . A method of detecting antibodies to hepatitis C virus (HCV), or diagnosis of HCV infection in a subject comprising: 
 (a) providing a peptide composition comprising a peptide selected from the group consisting of: 
 (i) Gln-Gly-Met-Met-Leu-Ala-Glu-Gln-Phe-Lys-Gln-Lys-Ala-Leu-Gly-Leu-Leu-Gln-Thr-Ala-Ser-Arg-Gln-Ala-Glu-Val-X 
 wherein X is —OH or —NH 2    
 
 (ii) an analog peptide of peptide (i) having an amino acid sequence from a strain/isolate of HCV in a region corresponding to peptide (i) and having specific immunoreactivity to antibodies to HCV;  
 (iii) a segment or truncated sequence of peptide (i) or said analog peptide which has specific immunoreactivity to antibodies to HCV; and  
 (iv) a conjugate or fusion protein of peptide (i), said analog peptide, or said segment or truncated sequence, wherein the conjugate or fusion protein has specific inimunoreactivity to antibodies to HCV;  
   (b) contacting an effective amount of the peptide composition with a sera or body fluid sample from the subject; and    (c) detecting a complex of the peptide composition and antibodies to HCV.    
   
   
       3 . The method according to  claim 2  wherein the peptide composition is coated on a solid substrate.  
   
   
       4 . The method according to  claim 3  wherein the step of detecting the complex of peptide with antibodies to HCV is determined by means of an enzyme linked immunosorbent assay.  
   
   
       5 . The method according to  claim 3  wherein the method of detecting the complex of peptide with antibodies to HCV is determined by using an radioimmunoassay.  
   
   
       6 . The method according to  claim 2  wherein the method of detecting the complex of peptide with antibodies to HCV is determined by a hemagglutination assay.  
   
   
       7 . A method of detecting antibodies to hepatitis C virus (HCV), or diagnosis of HCV infection in a subject comprising: 
 (a) providing a peptide composition comprising a peptide having an amino acid sequence as follows: 
 Gln-Gly-Met-Met-Leu-Ala-Glu-Gln-Phe-Lys-Gln-Lys-Ala-Leu-Gly-Leu-Leu-Gln-Thr-Ala-Ser-Arg-Gln-Ala-Glu-Val-X 
 wherein X is —OH or —NH 2 ;  
 or  
 
 an analog of the above peptide having an amino acid sequence from a strain/isolate of HCV in a region corresponding to the peptide, and having specific imrnmunoreactivity to antibodies to HCV;  
   (b) contacting an effective amount of the peptide composition with a sera or body fluid sample from the subject; and    (c) detecting the presence of a complex of the peptide and antibodies to HCV.