Relationship between the intrahepatic expression of 'e' and 'c' epitopes of the nucleocapsid protein of hepatitis B virus and viraemia.

The relationship between hepatitis B viraemia and intrahepatic HBV nucleocapsid proteins (HBcAg and HBeAg) was studied in 18 patients with chronic hepatitis B. Monoclonal antibodies (MoABs) were obtained in BALB/c mice primed with recombinant HBV nucleocapsid proteins. Four MoABs reacting with recombinant proteins gave positive results in competitive assays. Two reacted as anti-HBc and two as anti-HBe. One of them showed a strong affinity for the cytoplasmic, membrane bound antigen (P23e) of infected hepatocytes while the latter showed a higher specificity for serum HBeAg than for the intraheptic antigen. Anti-HBeMoA Bs had a staining capacity for liver cell nuclei comparable with that of polyclonal antibodies. Overall the anti-HBc MoABs stained the liver cell nuclei in 86% of cases, while anti-HBc MoABs stained in 58% of cases. The hepatoeytc cytoplasm was stained by anti-HBc MoABs and anti-HBe MoABs in 64% and 72% of cases respectively. Not one of 12 control liver biopsies was stained. Viraemia (HBV-DNA) was measured by dot blot hybridization and was correlated with the number of hepatocytes containing the nucleocapsid antigen. The highest levels of HBV-DNA (>108 genomes/ml) were detected in patients with prevalent nuclear staining while the lowest ones were observed in those with prevalent eytoplasmic expression of this antigen. The application of anti-HBV-nueleocapsid MoABs in diagnostics requires careful scrutiny since some are specific for the circulating antigen while others show a higher afffinity for the intrahepatic antigen. [ABSTRACT FROM AUTHOR]