The invention relates to the discovery of an HEV strain from a chronically infected patient. The virus grow unusually well in numerous cell cultures. Thus, the invention provides cell cultures, vectors, and vaccine compositions based on the virus.

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.

Hepatitis E 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 are 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.

Hepatitis E 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 are 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.

Polybrene as an additive in cell culture medium is used in methods for the generation of high-titer hepatitis E virus stocks and assays for titration of hepatitis E virus. A cell culture medium containing polybrene is used for high-titer HEV generation, a method for determining the presence and/or the level of HEV in a sample, and an HEV titration assay using polybrene.

A method of purification of non-enveloped or pseudo-enveloped virus produced in vitro uses a composition with at least one detergent. A method of purification can use multiple detergents, and a method of determining the presence and/or level of a non-enveloped or pseudo-enveloped virus in a sample includes treating with at least one detergent.

Polybrene as an additive in cell culture medium is used in methods for the generation of high-titer hepatitis E virus stocks and assays for titration of hepatitis E virus. A cell culture medium containing polybrene is used for high-titer HEV generation, a method for determining the presence and/or the level of HEV in a sample, and an HEV titration assay using polybrene.