title: X antigen/antibody markers in hepadnavirus infections. Presence and significance of hepadnavirus X gene product(s) in serum.
abstract: The finding that X antigen is associated with hepatitis B core antigen particles and that serum hepatitis B e antigen derives from the cleavage of one or more core associated polypeptides raises the question as to whether core associated X antigen could be similarly generated and released into serum. To test this hypothesis, antisera raised to X antigen peptides were used to construct an enzyme-linked solid-phase immunoassay to detect X antigen in sera from patients infected with hepatitis B virus and from woodchucks infected with woodchuck hepatitis virus. X antigen was present in more than half of the individuals tested. There was a significant association between X antigen and markers of viral replication. Most individuals destined to become surface-antigen carriers had X antigen appearing before surface antigen, as did a smaller proportion of individuals transiently positive for surface antigen. A high frequency of X antigen was observed only in sera from human populations with a high frequency of other hepatitis B virus markers. These results suggest that X is a newly identified serum marker of viral replication that often appears before surface antigen in productive infections.
authors.affiliation: Fox Chase Cancer Center, Philadelphia, Pennsylvania.
authors.forename: M A
authors.initials: MA
authors.lastname: Feitelson
authors.forename: M M
authors.initials: MM
authors.lastname: Clayton
authors.forename: B S
authors.initials: BS
authors.lastname: Blumberg
mesh_terms: D000818:Animals; D004797:Enzyme-Linked Immunosorbent Assay; D006508:Hepatitis Antibodies / Q000032:analysis; D006509:Hepatitis B / Q000276:immunology*; D006512:Hepatitis B Core Antigens / Q000276:immunology; D006515:Hepatitis B virus / Q000276:immunology*; D006518:Hepatitis Viruses / Q000276:immunology*; D006524:Hepatitis, Viral, Animal / Q000276:immunology*; D006801:Humans; D008392:Marmota; D012589:Sciuridae; D015534:Trans-Activators / Q000032:analysis*; D014760:Viral Fusion Proteins / Q000032:analysis*; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D006508:Hepatitis Antibodies; D006512:Hepatitis B Core Antigens; D015534:Trans-Activators; D014760:Viral Fusion Proteins; D054334:Viral Regulatory and Accessory Proteins; C063377:X antigen, viral infections; C057628:hepatitis B virus X protein