Sequential studies of pre-S2 antigenemia and anti-pre-S2 antibodies in relation to viral replication in acute hepatitis B followed from the early incubation phase

Peptide immunogen mimicry of putative E1 glycoprotein-specific epitopes in hepatitis C virus

Hepatitis C virus (HCV) accounts for most cases of acute and chronic non-A and non-B hepatitis with serious consequences that may lead to hepatocellular carcinoma. The putative envelope glycoproteins (E1 and E2) of HCV probably play a role in the pathophysiology of the virus. In order to map the immunodominant domains of the E1 glycoprotein, two epitopes from amino acid residues 210 to 223 (P1) and 315 to 327 (P2) were predicted from the HCV sequence. Immunization of mice with the synthetic peptides conjugated to bovine serum albumin induced an antibody response, and the antisera immunoprecipitated the E1 glycoprotein (approximately 33 kDa) of HCV expressed by recombinant vaccinia virus. A panel of HCV-infected human sera was also tested with the synthetic peptides by enzyme-linked immunosorbent assay for epitope-specific responses. Of 38 infected serum samples, 35 (92.1%) demonstrated a spectrum of reactivity to the P2 peptide. On the other hand, only 17 of 38 (44.7%) serum samples were reactive to the P1 peptide. Strains of HCV exhibit a striking genomic diversity. The predicted P1 epitope showed localization in the sequence-variable region, and the P2 epitope localized in a highly conserved domain. Results from this study suggest that the E1 glycoprotein of HCV contains at least two potential antigenic epitopes. Synthetic peptides corresponding to these epitopes and antisera to these peptides may serve as the monospecific immunological reagents to further determine the role of E1 glycoprotein in HCV infection.

Hepatitis B pre-S1 and pre-S2 proteins: clinical significance and relation to hepatitis B virus DNA

Pre-S proteins may have an important role in virus assembly and virus entry into the host cell. The presence of pre-S proteins in serum has also been thought to correlate with active viral replication. To investigate whether pre-S proteins in serum might have additional diagnostic and/or predictive value for liver sequelae in HBV infection, sera from six different serological groups of patients with HBV markers (total number 363) and different manifestations of liver histology were examined for the presence of pre-S1 and pre-S2 proteins using micro-ELISAs. Pre-S1 and pre-S2 proteins were detected significantly more often in HBV-DNA-positive than in HBV-DNA-negative sera from HBsAg carriers. However, pre-S1 and pre-S2 proteins were also found in HBV-DNA-negative HBsAg carriers irrespective of serum HBeAg/anti-HBe or liver histologic findings. These results suggest that the presence of the pre-S1 and or pre-S2 proteins in serum either does not seem to reflect the presence of active viral replication and active liver disease or pre-S proteins are more readily detectable than HBeAg and HB-DNA as measured by a dot-blot technique. Furthermore, the presence of pre-S proteins in serum is strongly correlated with that of HBsAg.

Clearance of hepatitis B virus DNA and pre-S surface antigens in patients with markers of acute viral replication

To clarify the relationship between the pre-S antigens and other serological markers of hepatitis B virus (HBV) replication, we followed up 27 patients: 21 presented with symptoms of acute hepatitis (two progressed to chronicity) and six suffered from chronic hepatitis. Pre-S1, pre-S2, HBV DNA, IgM antihepatitis core antigen (HBc), hepatitis B e antigen (HBeAg), and anti-HBe were detected in about 200 sera serially collected at different times for at least 6-12 months from the onset of clinical observation. In the early symptomatic phase of acute hepatitis, the pre-S1 and pre-S2 antigens were present in 95% of the cases and correlated well with high levels of alanine-transferase (ALT) and IgM anti-HBc, while HBV DNA was present in the sera of only six (28.6%) patients (P less than 0.0001). This was the first marker to disappear (1 month after the initial stage). All of the HBV DNA-positive patients were also HBeAg positive, whereas no HBeAg-negative subjects were found with serum HBV DNA. In the six chronic patients, pre-S antigens were always present independently of the HBeAg/anti-HBe status; HBV DNA was detected in three of them, even if transiently, and in two of these it reappeared together with pre-S2 epitope. The follow-up data suggest that, in acute hepatitis, the clearance of pre-S antigens can be considered as a prognostic index of clinical resolution and that, in chronic hepatitis, the persistence of pre-S antigens seems to indicate progression of the disease. In particular, pre-S2, in patients in whom it is intermittent, can be considered as an index of reactivation.