Hepatitis e virus orf2 capsid polypeptides and uses thereof

Abstract

Hepatitis F virus (HEV) is responsible for over 50% of acute viral hepatitis cases worldwide. The inventors have now identified the precise sequence of infectious particle-associated ORF2 capsid protein. Strikingly, their analyses revealed that in infected patients, HEV produces three forms of the ORF2 capsid protein: ORF2i, ORF2g and ORF2c. The ORF2i protein is associated with infectious particles whereas ORF2g and ORF2c proteins are massively produced glycoproteins that are not associated with infectious particles and arc the major antigens present in HEV-infected patient sera. Accordingly, the ORF2i and ORF2g proteins are thus the subject matter of the present invention as well as antibodies specific for the proteins and diagnostic assays (e.g. ELISA) for the diagnosis of Hepatitis E virus infection.

1 . A method for detecting the presence of infectious particles of hepatitis E virus in a sample comprising contacting the sample with an antibody having specificity for the ORF2i polypeptide and/or an antibody having specificity for the ORF2g polypeptide under conditions that allow an immunocomplex of an antibody and the infectious particles to form, wherein detection of the immunocomplex indicates the presence of the infectious particles in the sample. 
     
     
         2 . The method of  claim 1  wherein the sample is selected from the group consisting of blood ascites; urine; saliva; sweat; milk; synovial fluid; peritoneal fluid; amniotic fluid; percerebrospinal fluid;
 lymph fluid; lung embolism; cerebrospinal fluid; pericardial fluid and faeces. 
 
     
     
         3 . A method for diagnosing hepatitis E virus (HEV) infection in a subject in need thereof, comprising contacting the sample with an antibody having specificity for the ORF2i polypeptide under conditions that allow an immunocomplex of an antibody and infectious HEV particles to form, wherein detection of the immunocomplex indicates that the subject has an HEV infection. 
     
     
         4 . The method of  claim 3  wherein the HEV infection is an acute HEV infection, a recent HEV infection, a chronic HEV infection or a weak active HEV infection. 
     
     
         5 . A method for diagnosing a cleared HEV infection in a subject in need thereof, comprising contacting a sample from the subject with an antibody having specificity for the ORF2g polypeptide under conditions that allow an immunocomplex of an antibody and the ORF2g polypeptide to form, wherein detection of the immunocomplex indicates that the subject has cleared an HEV infection.