Correlation of replication efficiency and antigen expression of HBV strains in vivo and in transfected cells

Objective To study the correlation of replication efficiency and antigen expression of hepatitis B virus (HBV) strains in patient sera and transfected cells. Methods Quantification of five maternal serum HBV DNA was carried out using dot hybridization and polymerase chain reaction-enzyme linked immunosorbent assay (PCR-ELISA), hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) levels in the sera were determined by ELISA. Full-length genomes of HBV strains cloned from five pregnant women were separately used to transfect HepG2 cells. The levels of HBsAg and HBeAg in the supernatant of transfected cells were determined with Abbott EIA kits, the replication efficiency of intracelluar replicative intermediates and extracellular HBV DNA of viral particles was analyzed by Southern blot and hybridization. Results Intracellular and extracellular HBV replication and antigen expression of cloned HBV strains showed positive correlation tendency with the HBV DNA and antigen levels in serum samples. Conclusions Virus replication efficiency and expression of HBsAg and HBeAg by full-length HBV clones are in relative coincidence with the biological characteristics of HBV strains in patients. Cell transfection can be used to study the biological characteristics of individual isolates.