Novel hepatitis B virus

Abstract

We isolated and characterized a new surface mutant of the hepatitis B virus surface antigen (HBsAg). The mutant was isolated from a symptomatic patient with Down's syndrome who was found to be persistently positive for both HBsAg and anti-HBs Antibody (Ab) with an equally long-lasting anti-HB core (c) IgM Ab.

1 . (canceled)  
     
     
         2 . (canceled)  
     
     
         3 . A monoclonal antibody raised against a variant hepatitis B surface antigen, the variant hepatitis B surface antigen comprising an amino acid sequence wherein mutations from hepatitis B wild type ayw2 strain having SEQ ID NO:7 appear as follows: at position 103 isoleucine is present instead of methionine, at position 118 lysine is present instead of threonine, at position 120 glutamine is present instead of proline, at position 175 serine is present instead of leucine, and at position 213 serine is present instead of leucine.  
     
     
         4 . A hybridoma cell line which secretes the monoclonal antibody of  claim 3 .  
     
     
         5 . An assay kit for determining the presence of hepatitis B in a test sample, comprising: a container containing at least one monoclonal antibody which specifically binds to hepatitis B surface antigen wherein the monoclonal antibody is a monoclonal antibody secreted by the hybridoma cell line claimed in  claim 4 .  
     
     
         6 . A method for determining the presence of hepatitis B in a test sample, comprising: 
 a. contacting a test sample with at least one monoclonal antibody claimed in  claim 3  attached to a solid phase, to form a mixture,    b. incubating the mixture for a time and under conditions sufficient to form antigen-antibody complexes,    c. contacting the complexes with an antibody conjugated to a signal generating reagent that is specific for the complexes, and    d. determining the presence of hepatitis B present in the test sample by detecting the signal generated.