X antigen/antibody markers in hepadnavirus infections. Presence and significance of hepadnavirus X gene product(s) in serum

• Published in: Gastroenterology (New York, N.Y. 1943) Vol. 98; no. 4; p. 1071
• Main Authors: Feitelson, M A, Clayton, M M, Blumberg, B S
• Format: Journal Article
• Language: English
• Published: United States 01.04.1990
• Subjects: Animals; Enzyme-Linked Immunosorbent Assay; Hepatitis Antibodies - analysis; Hepatitis B - immunology; Hepatitis B Core Antigens - immunology; Hepatitis B virus - immunology; Hepatitis Viruses - immunology; Hepatitis, Viral, Animal - immunology; Humans; Marmota; Sciuridae; Trans-Activators - analysis; Viral Fusion Proteins - analysis
• ISSN: 0016-5085
• DOI: 10.1016/0016-5085(90)90035-Y

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.