A method for diagnosing hepatitis virus infection or a hepatitis disease condition in a subject based on hepatitis virus-associated biomarkers present on exosomes in a bodily fluid sample from the subject is disclosed. Also disclosed are a method for monitoring the course of a hepatitis virus infection or a hepatitis disease condition in a subject and a method for-monitoring effectiveness of treatment to a subject with an anti-hepatitis virus agent based on hepatitis virus-associated biomarkers present on exosomes in bodily fluid samples from the subject, as well as a kit for diagnosing hepatitis virus infection and/or a hepatitis disease condition in a subject based on hepatitis virus-associated biomarkers on exosomes in bodily fluid samples from the subject.

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.

A method for diagnosing hepatitis virus infection or a hepatitis disease condition in a subject based on hepatitis virus-associated biomarkers present on exosomes in a bodily fluid sample from the subject is disclosed. Also disclosed are a method for monitoring the course of a hepatitis virus infection or a hepatitis disease condition in a subject and a method for monitoring effectiveness of treatment to a subject with an anti-hepatitis virus agent based on hepatitis virus-associated biomarkers present on exosomes in bodily fluid samples from the subject, as well as a kit for diagnosing hepatitis virus infection and/or a hepatitis disease condition in a subject based on hepatitis virus-associated biomarkers on exosomes in bodily fluid samples from the subject.

Provided herein are compositions, systems, and methods for assessing and monitoring disease stage and phases, predicting likelihood of disease progression, and predicting and monitoring responses to hepatitis B virus infection.

Provided are a kit for measuring a titer of a human antibody, a humanized antibody, or a human Fc-fusion protein in human plasma or serum, and a method for measuring a titer of a human Fc-containing protein in human plasma or serum using the same, and more specifically, a kit for measuring a titer of human Fc-containing protein in human plasma or serum, the kit including a diluent for sample, a diluent for conjugate, and a cleansing solution and being used in analysis through an indirect enzyme-linked immunosorbent assay (indirect ELISA), and a method for measuring a titer of human Fc-containing protein in human plasma or serum using the same.

Provided herein are, inter alia, antibodies, antigen-binding antibody fragments, cells, polynucleotides, compositions, kits, and methods relating to the detection of HBV protein X (HBx), e.g., in vitro and in vivo. Included are antibodies and fragments thereof that bind HBx, as well as kits, cells, and compositions comprising such antibodies and fragments.

A virus infection model which overcomes the drawbacks of conventional hepatitis virus infection models is provided.

A method for constructing a virus infection model capable of recapitulating a viral life cycle, comprising infecting a cell condensate formed by culturing a tissue or organ cell in vitro with a virus. A virus infection model capable of recapitulating a viral life cycle, comprising a virus-infected cell condensate, wherein the cell condensate is formed by culturing a tissue or organ cell in vitro. A method of screening for substances with antiviral activity, comprising using the virus infection model.

A method for diagnosing hepatitis virus infection or a hepatitis disease condition in a subject based on hepatitis virus-associated biomarkers present on exosomes in a bodily fluid sample from the subject is disclosed. Also disclosed are a method for monitoring the course of a hepatitis virus infection or a hepatitis disease condition in a subject and a method for monitoring effectiveness of treatment to a subject with an anti-hepatitis virus agent based on hepatitis virus-associated biomarkers present on exosomes in bodily fluid samples from the subject, as well as a kit for diagnosing hepatitis virus infection and/or a hepatitis disease condition in a subject based on hepatitis virus-associated biomarkers on exosomes in bodily fluid samples from the subject.

Provided are methods and assays used in the screening and identification of agents in assays that use metabolically active cells.

The present invention relates to a pretreatment method of a sample for detecting HBs antigen, which is a surface antigen of the hepatitis B virus, and a method for detecting HBs antigen utilizing the pretreatment method. The present invention also relates to a pretreatment reagent kit for detecting HBs antigen.